• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a motor spindle (11) for driving a tool that is directly clamped or held in a tool holder with: - a spindle shaft (19) driven by means of a drive unit (17), - a tool interface (21) for the detachable, rotationally fixed coupling of the tool holder to the spindle shaft (19), - a bearing device (23) for rotatably mounting the spindle shaft (19), - a housing (25) in which the spindle shaft (19), the bearing device (23) and the drive unit (17) are accommodated. In order to provide an improved motor spindle (11), it has a control loop which is structurally integrated into the motor spindle and has at least two fiber-reinforced plastic materials that are set differently in terms of rigidity, thermal conductivity and / or thermal expansion coefficient.
    公开号:CH715948A2
    申请号:CH00266/20
    申请日:2020-03-06
    公开日:2020-09-15
    发明作者:Klimach Martin；Brechtel Alexander
    申请人:Carbon Drive Gmbh；
    IPC主号:
    专利说明:

    Field of invention
    The invention relates to a motor spindle for driving a tool or held in a tool holder tool, with a spindle shaft driven by a drive unit, a tool interface for releasably non-rotatable coupling of the tool holder to the spindle shaft, a bearing device for rotatably mounting the spindle shaft and a housing, in which the spindle shaft, the bearing device and the drive unit are accommodated and a method for regulating such a motor spindle.
    State of the art
    [0002] Motor spindles for driving a tool held in a tool holder are known. These are usually used for machining, in particular machining, of materials. For such processing, comparatively high speeds and frequent acceleration and braking processes are required. In addition, the driven tool may also have to be changed several times during the machining of a workpiece. As a result, alternating thermal loads and vibration excitations occur on generic motor spindles in the course of a machining process. Waste heat from the drive unit and frictional losses of the bearing device for mounting the spindle shaft and possibly process heat on the tool occur as heat sources. This heat can be dissipated, for example, by means of compressed air and / or water cooling. Due to the high speeds, dynamic loads such as centrifugal forces occur, in particular on the bearing device, which, in addition to the thermal load, can also lead to changes in operating parameters of the motor spindle. It is known to use a fiber-reinforced plastic material for motor spindles, which is also known as such in principle. EP 3 069 848 A1 shows, for example, from a very distant technical field of the production of sporting goods, a method for shaping a fiber-reinforced composite material structure with the following steps: providing a preform which has at least one layer and an adjoining second layer, each of the Layers comprising a resin matrix and fibers and wherein a direction of the fibers of the first layer differs from a direction of the fibers of the subsequent layer; a helical winding of the preform around a core from a first end region of the core to a second end region of the core and / or from the second end region to the first end region so that the direction of the fibers in the first layer are relative to an axial direction of the core Increase an efficiency. The preparation and winding of the layers is repeated until a three-dimensional specific structure is defined. This is optionally pressurized and solidified by a heat treatment cycle. A hollow shaft can be obtained by removing the core. DE 197 26 341 A1 relates to a shaft of a motor-driven spindle with a rotor connected to it, the shaft being made of reinforced plastic (composite material) and the rotor being integrated into the shaft material. The rotor is wrapped in reinforced plastic material. The rotor can have grooves in which the winding engages. The reinforced plastic is preferably a CFRP material. From DE 40 09 461 A1 a spindle for a machine tool is known. This comprises a cylindrical element for receiving the shank of a tool. It is made by winding carbon or glass fibers, whereby the wound fiber is impregnated with a thermosetting resin. After the resin has hardened, a protective coating layer is applied to the outer surface of the cylindrical member. With this structure, it is possible to reduce the weight and the linear thermal expansion coefficient of the spindle and thereby improve the machining accuracy.
    Presentation of the invention
    The object of the invention is to provide an improved motor spindle for driving a tool held in a tool holder, in particular to improve the service life of the motor spindle, to facilitate a tool change, to reduce the size of the motor spindle, to improve cooling of the motor spindle and / or to enable higher speeds.
    The object is achieved with a motor spindle for driving a tool held in a tool holder according to the preamble of claim 1 in that the motor spindle has a control loop that is structurally integrated into the motor spindle with at least two in terms of rigidity, heat conduction property and / or thermal Has expansion coefficients set differently fiber-reinforced plastic materials. It has been found that fiber-reinforced plastic materials can be adjusted in a comparatively large range in terms of the properties of elasticity and / or stiffness, thermal conductivity properties and the coefficient of thermal expansion due to the composition of the plastic material and the fibers. In particular in comparison to steel, advantageous material properties can be provided for the motor spindle exactly where they positively influence the performance of the motor spindle, in particular a service life, an acceleration and braking behavior, a vibration behavior and / or a speed. In addition, it was found that the different setting of the plastic materials is also possible in an integrally connected component. It is therefore conceivable to adapt an integrally connected component, such as the spindle shaft of the motor spindle, to technical requirements in certain areas, in particular elasticities, in order to have a positive influence on the vibration behavior. The different setting of the fiber-reinforced plastic materials can also be done by a combination of two components, for example in the form of a spacer ring combined with the spindle shaft and / or the like. The setting of the fiber-reinforced plastic material can in particular take place through a combination of different layers, an alignment of fibers and / or the choice of fibers. In particular, it is thereby possible to set a coefficient of thermal expansion of zero or possibly even less than zero. It was also found that these specific properties can also be used to implement control loops that respond to heat. A fiber-reinforced plastic material can in principle be understood to mean a resin and / or substrate, in particular thermosetting, by means of which different layers of fibers are impregnated and cured. In particular, the fibers can be carbon fibers, that is to say a so-called CFRP material. This advantageous combination of differently adjusted fiber-reinforced plastic materials enables speeds of over 30,000, preferably up to 60,000 revolutions per minute to be achieved, with accelerations and decelerations being possible every second. In addition, the result is a comparatively small motor spindle, and any contours of the motor spindle which interfere with the machining of the workpiece can be reduced to a minimum. The reduction of the interfering contour results from the fact that, due to the advantageous fiber-reinforced plastic material (s), in particular CFRP materials, in particular with a thermal coefficient of thermal expansion of zero, the motor spindle, in particular a housing of the motor spindle, can be held at any point without the precision of the Machine to deteriorate. Steel motor spindles known from the prior art are connected to a manipulation device as close as possible to the tool in order to minimize thermally induced offsets, in particular axial offsets, on the tool and thus machining errors. This manipulation device inevitably represents an interfering contour for the machining process. The motor spindle according to the invention minimizes this interfering contour, since it can be connected to the manipulation device at any point, possibly also at an end opposite the tool, without producing thermal machining errors. This is possible because, in particular, by using a fiber-reinforced plastic material with a thermal expansion coefficient of zero or close to zero, the connection between temperature and geometry changes is at least largely eliminated. A novel motor spindle according to the invention can therefore be held on the side facing away from the tool, so that a holding structure of the manipulation device protrudes considerably less into a machining area and therefore interferes less during machining. The new motor spindle can therefore be attached to a manipulation device at any axial distance from the tool without loss of precision. During operation, there is an axial distance between the processing point or the tool and the said fastening point with a minimal interference contour of more than 20%, in particular more than 50%, in particular more than 80%, in particular a total length of the housing, of the novel motor spindle. In addition, the motor spindle itself has a comparatively low weight, so that it can also be positioned more easily and more precisely relative to the workpiece by means of an automated manipulation device.
    So it can be very well absorbed process forces with a high machining quality in terms of location, shape tolerances, concentricity and a small displacement of the tool relative to a desired position and high rigidity can be achieved at a large speed range, which has a high metal removal rate or a enable high productivity.
    The precision, as one of the most important criteria for motor spindles, can be significantly improved. Above all, the repeatability is significantly improved, so that the motor spindle according to the invention, in particular with changing temperatures, delivers reproducible milling results at a consistently good level. In comparison to motor spindles made of steel, which expand very strongly under the influence of heat, the repeatability is enormously improved. In addition, an effort known and carried out from the prior art in steel motor spindles for generating the repeat accuracy can be reduced to zero, at least to a minimum, by providing the differently adjusted fiber-reinforced plastic materials. The advantageous embodiment is already structurally specified in the differently adjusted fiber-reinforced plastic materials, in particular any software control loops that may be required are not required or can be reduced to a minimum. Rather, it is even possible to integrate the control loop directly into the motor spindle using the structurally specified hardware in the form of fiber-reinforced plastic materials. This means that, for example, a laminate structure of the motor spindle is designed in such a way that it no longer expands in the axial direction. In particular, a coefficient of thermal expansion of zero can be provided in the fiber-reinforced plastic materials. This makes it possible to dispense with virtually all compensation systems, so that the motor spindle can not only be manufactured more cheaply, but is also more precise at the same time. The rapid acceleration of the motor spindle as a whole, as well as the start-up and shut-down, result in particularly short cycle times. Together with the possibly achievable higher speeds with the same precision, a higher material removal per time, that is a higher metal removal rate, is possible. This is achieved by a higher rigidity of the motor spindle with a reduced weight at the same time. In particular, the fiber-reinforced plastic materials, in particular CFRP materials, have damping properties that are up to 100 times better than conventional materials such as steel, which results in significantly higher dynamic stiffnesses. In particular, critical frequencies can be shifted into a non-disruptive area. This also enables a rigid mounting of the motor spindle which can be manufactured or manufactured from the fiber-reinforced plastic material. A floating bearing, which may otherwise be required and which is known in the prior art to compensate for thermal expansions, can be dispensed with. A possibly required sliding fit inside the motor spindle can therefore be dispensed with. The motor spindle is therefore mounted without a sliding seat or loose bearing by means of a bearing device. In addition, it is known to use the differently adjusted fiber-reinforced plastic materials to adapt the motor spindle at least in certain areas so that it adapts to the requirements of the bearing devices due to centrifugal forces and / or temperature influences. In particular, an expansion caused by centrifugal force can be adapted in such a way that a press fit of roller bearings pressed onto the spindle shaft, in particular ball bearings, has sufficient holding force even at high speeds. Slipping through of the inner bearing rings due to an expansion caused by centrifugal force can thus be reliably prevented. An undesired lifting of the bearing from the spindle shaft at high speeds is thus prevented. In all operating conditions, whether standstill or maximum speed, there is sufficient surface pressure between the bearings or bearing inner rings and the spindle shaft. In comparison to a bearing on steel shafts, a loss of surface pressure can be prevented by an expansion of the centrifugal force. This enables bearings to be placed directly on the spindle shaft, it being possible to dispense with a steel sleeve arranged radially between the bearing and the spindle shaft. The bearing device is thus formed radially without an intermediate sleeve. In addition, the differently adjusted fiber-reinforced plastic materials can provide a very lightweight and high-strength motor spindle. As a result, speeds of up to 30,000, preferably up to 60,000 revolutions per minute can be achieved, with acceleration and deceleration being possible every second. These speeds can be achieved, for example, with bearings that are lubricated for life and a bearing bore diameter of 40 mm in a rigid position. For other bearing designs, there are other speed ranges which, compared to known concepts, enable significantly higher speeds without any loss of quality. This has decisive advantages for the dynamics and energy efficiency of a cutting machine having the motor spindle.
    In a preferred embodiment it is provided that a first of the fiber-reinforced plastic materials is arranged between the storage device and a cooling device. This first of the fiber-reinforced plastic materials has a direction-dependent thermal conductivity that is increased in one direction between the storage device and the cooling device. The direction between the storage device and the cooling device can in particular be understood as an imaginary direct connection between the storage device and the cooling device. However, it can also be understood to mean a curved or otherwise configured heat conduction path between the bearing device and the cooling device. In a further direction running at an angle to the direction, the first fiber-reinforced plastic material has a comparatively lower thermal conductivity. As a result, a heat flow from the storage device to the cooling device can be improved and a desired temperature control of the storage device can thus be achieved.
    Alternatively or additionally, it is possible in this context that the first fiber-reinforced plastic material has aligned heat conducting fibers. It has been found that a directional thermal conductivity can be set by means of the fibers, which are required in any case for fiber-reinforced plastic materials. This can be expanded to values a multiple of conventional materials such as steel, in particular up to a factor of 30. In particular, carbon fibers on a pitch basis with a high thermal conductivity of 100-600 W / mK, in particular 300 to 600 W / mK, have been found to be particularly suitable. The first fiber-reinforced plastic material therefore has, in particular, pitch fibers.
    Alternatively or additionally, it is also conceivable that the heat conducting fibers run essentially between the storage device and the cooling device. This makes it possible for each individual one of the heat-conducting fibers to form a partial heat-conducting path, which add up to form a heat-conducting path that runs from the bearing device to the cooling device.
    It is preferably provided that a bearing plate of the bearing device has the first fiber-reinforced plastic material. The end shield of the bearing device therefore preferably has the aligned heat-conducting fibers and thus the advantageous heat-conducting path. The end shield can be arranged in direct, heat-transferring contact with bearing outer rings of bearings of the bearing device. In this way, heat generated in the bearings, in particular frictional heat, can be transferred directly from the respective bearing outer ring to the end shield and from there to the cooling device via the aligned heat-conducting fibers. For this purpose, the cooling device can likewise be in heat-transferring contact contact with a side of the end shield opposite the outer bearing rings. In particular, it is conceivable that the radially outer side of the end shield is arranged adjacent to a fluid path of the cooling device that carries a cooling medium, for example water. As a result, the heat generated in the outer ring of the respective bearing can be transferred directly to the heat-carrying fluid, in particular the water, via the end shield, ie in particular the aligned heat-conducting fibers. This results in particularly good cooling of the storage device.
    In a further possible embodiment, a spacer sleeve of the bearing device has the first fiber-reinforced plastic material. For spacing purposes, the spacer sleeve can be in heat-transferring contact contact with bearing inner rings of two bearings of the bearing device. The inner bearing rings are preferably fixed directly on the motor spindle, without loose bearings and / or radially without intermediate sleeves, in particular there by means of a press fit. Due to the heat-transferring contact contact, the frictional heat that occurs can be transferred to and from the spacer sleeve. In particular, a heat transfer medium, in particular compressed air, can be applied to the spacer sleeve for this purpose. The heat absorbed by means of the spacer sleeve can therefore be passed on by means of the compressed air and finally transported away. In particular, a surface of the spacer sleeve has a delimitation of a fluid path guiding the heat-conducting medium or the compressed air. The direct wetting means that the heat can be dissipated even better. As a result, the inner bearing rings of the bearing device can also be temperature-controlled or cooled very well.
    It is particularly preferably provided that the heat conducting fibers are cut on a surface of the first fiber-reinforced plastic material or at least run towards this surface. By running towards the surface, it can be understood that the fibers end just below the surface. In the case of direct incision, however, it can also be that these protrude from the surface or are directly exposed on it. As a result, particularly good heat transport or transition from the surface to the heat conducting medium and / or by means of the previously described heat-transferring contact contact can take place.
    According to a further additional or alternative embodiment, the spacer sleeve can have an indentation in which the heat-conducting fibers end, wherein the indentation can be acted upon with a heat-conducting medium in order to carry away heat. It is conceivable to manufacture the spacer sleeve in such a way that the heat conducting fibers run in a longitudinal direction of the motor spindle, in particular in a longitudinal direction of the spindle shaft. As a result, they basically run from a first inner bearing ring to a second inner bearing ring, the spacer sleeve being in heat-transferring contact with the inner rings at both ends and at the same time spacing them apart, in particular transmitting an axial bearing preload force. By means of the indentation, which can be produced, for example, by removing material, the heat-conducting fibers can be exposed in a simple manner. As a result, heat can be transported on both sides in the spacer sleeve from the respective inner bearing ring to a central region of the spacer sleeve. The heat is transported from the two ends of the spacer sleeve to a center of the spacer sleeve which has the indentation. In order to finally transport the heat away, the indentation can be acted upon by the heat-conducting medium, in particular pressure. This construction can also advantageously be used in the case of cooling devices that are already customary, in which compressed air is also introduced between two bearings. In summary, the advantageous heat-conducting fibers or the first fiber-reinforced plastic material with the directionally set thermal conductivity do not have to be provided on the entire motor spindle. Rather, the advantages can already be achieved in that the first fiber-reinforced plastic material is specifically provided on the end shield and / or the bearing sleeve, a customary fiber-reinforced plastic material known as such being used on the rest of the motor spindle, in particular a CFRP material.
    In a likewise possible embodiment, a second of the fiber-reinforced plastic materials is arranged on the tool interface and / or a fifth of the fiber-reinforced plastic materials on the bearing device, each of which, in particular individually adapted, has a comparatively higher rigidity in a longitudinal direction of the motor spindle than in one Circumferential direction of the motor spindle. The tool interface is usually designed so that the motor spindle encompasses the circumference of the tool holder in the assembled state. This creates a self-locking that must be overcome when changing tools, i.e. when removing the tool holder from the spindle shaft. As a result of the rigidity being reduced in the circumferential direction, a surface pressure that occurs during self-locking and thus the ejection force that is required to eject the tool holder can be reduced. A desired centering of the tool holder during coupling, that is, during operation of the motor spindle, is not impaired. In the opposite case, i.e. in the case of the bearings that are located radially outside the spindle shaft, a centrifugal force-related expansion of the spindle shaft can be increased, in particular it can be selected so that a surface pressure between the bearings of the bearing device placed on the spindle shaft and the spindle shaft despite centrifugal force-related expansion of the Bearing or inner rings of the bearing remains as constant as possible, is corrected at least as a result of the speed in such a way that lifting of the bearing from the spindle shaft can be reliably avoided. In this case it is therefore possible to combine the second fiber-reinforced plastic material with the fifth fiber-reinforced plastic material in just one component. With only one integral component, which has two differently adjusted fiber-reinforced plastic materials, the two advantages described above, i.e. easier ejection of the tool holder and preventing the inner rings of the bearing of the bearing device from lifting off, can be achieved. In addition, it is possible to design the entire spindle shaft so that it also has a thermal expansion coefficient of zero or at least almost zero, so that a third advantage, namely a temperature-independent precision or relative position of the tool to the workpiece, can be achieved. In this case, the differently adjusted fiber-reinforced plastic materials of the preferably integral spindle shaft can achieve three advantages. Alternatively, at least one of the fiber-reinforced plastic materials can also be provided for the different tasks described at two points of the integral component.
    [0015] It is preferably provided that a shaft cone of the spindle shaft that interacts with the tool holder has the second fiber-reinforced plastic material 45. The shaft cone is usually used to receive and center a conical hollow shank of the tool holder 13 in a self-locking planar contact contact. As described above, a surface pressure occurring in this case can be reduced by the above-described setting of the second fiber-reinforced plastic material 45, which enables the tool holder and thus the tool to be ejected more easily from the motor spindle.
    In an alternative that is also possible, it is conceivable that the spindle shaft has a flat system that interacts with the tool holder, the flat system and the shaft cone acting as a double fit for the tool holder, with a clamping force for clamping the tool holder being in a ratio of 90 to 70 10 to 30, preferably about 80 to 20, distributed over the planar contact with the shaft cone. It is possible for the tool interface to be designed as a standard part, with the shaft cone and the plane contact usually striking. When the tool holder is inserted into the spindle shaft, the surface pressure for centering is built up within the shaft cone, which in turn can be limited by means of the plane contact. When the tool holder is introduced into the motor spindle, forces act in a longitudinal direction of the spindle shaft or motor spindle. With a standard-compliant (DIN 69063) steel spindle, the force distribution from the face to the cone is, depending on the location of the manufacturing tolerances, from only 60 to 35 to 40 to 65. The proportion that occurs on the shaft cone causes the ejection force required in the opposite direction. It can be seen that by reducing the proportion from 65 to 40 to 10 to 30, preferably 20, a significant reduction in the ejection force is possible. As a result, both an ejection device provided for ejecting the tool holder and a clamping device provided for clamping the tool can be designed to be significantly weaker and therefore smaller. The ejection device can therefore have comparatively smaller means for ejecting and / or clamping the tool holder. In particular, it can be a linear drive, for example a magnetically actuated, pneumatically actuated and / or hydraulically actuated linear drive for applying the force required to the tool holder during ejection and / or clamping.
    An additional embodiment provides that a clamping tube of the tool interface has a third of the fiber-reinforced plastic materials, the third fiber-reinforced plastic material having a comparatively high internal damping. When the motor spindle is operated, vibrations that stimulate vibrations or pulsating forces are transmitted from the tool. When the tool interface is clamped, these also act on the clamping tube. Due to the comparatively high internal damping, the longitudinal and / or radial vibrations of the clamping tube can be reduced to a minimum. In particular, corresponding resonance frequencies can be increased, preferably shifted into a non-critical range. This effect occurs through the combination of the differently adjusted fiber-reinforced plastic materials, with the comparatively high internal damping only having to be provided on the components that are particularly susceptible to vibration. The comparatively high internal damping can, however, also be provided in areas at other points on the motor spindle that are particularly susceptible to vibration.
    A preferred embodiment is designed so that a fourth of the fiber-reinforced plastic materials has a coefficient of thermal expansion different from another component of the motor spindle and / or an intermediate ring of the bearing device has the fourth fiber-reinforced plastic material. In particular, the intermediate ring has a coefficient of expansion, in particular with a coefficient of thermal expansion of zero or at least close to zero. This results in a different thermal expansion of the spindle shaft and the intermediate ring placed on it. This enables a temperature-dependent spacing of two roller bearings, in particular ball bearings, in particular two bearing inner rings of the two ball bearings of the drive unit 17. The intermediate ring is preferably in force-transmitting contact contact with the inner rings of the ball bearings of the bearing device. It has been found that a kinematic displacement of rolling elements and / or bearing rings of the bearings of the bearing devices occurring at high speeds can shift or increase a preload force of the bearings into an undesired range. This results in increased friction and consequently increased heating of the bearings. This heating is transferred to the spacer sleeve, so that it is smaller than the spindle shaft. This automatically reduces the bearing preload and thus the amount of heat generated. The specially adjusted fourth fiber-reinforced plastic material in combination with the fiber-reinforced plastic material of the spindle shaft thus forms a control loop for adjusting the axial preload of the bearings of the bearing device. This results in a speed-independent or speed-independent mounting of the spindle shaft, which leads to a longer service life of the bearing device due to the reduced friction that can be achieved therewith. In principle, the fourth fiber-reinforced plastic material can be provided on at least any component of the bearing device located in the force flow of the axial preload force, in particular on a rotor carrier arranged between the bearing pairs, on the end shields, on the spindle shaft and / or on the inner and / or outer intermediate ring .
    Alternatively or additionally, it is possible that the fourth fiber-reinforced plastic material and / or the intermediate ring is arranged between two bearings of the bearing device, with an axial preload force being transferable to the bearing and a heat flow from the bearings into the intermediate ring , whereby an increase in temperature of the intermediate ring causes a reduction in the axial preload force. As a result, a control loop is formed, the axial preload force representing the control variable of the control loop. The bearings themselves serve as measuring elements, which indirectly absorb or measure the axial preload force via the increased friction and the resulting increased heat flow. The intermediate ring serves as a controller and as an actuator at the same time. Due to the negative thermal expansion coefficient, this reduces the axial preload force when the temperature rises. The speed and thus the kinematic displacement, which increases the axial pre-tensioning force, acts as a disturbance variable in this control loop. Other disturbance variables can also be changes in the length of spacer sleeves, shafts or other parts that are in the force flow of the bearings. The disturbance variables are counteracted by the use of reinforced plastic materials, which at the same time leads to a desired temperature reduction at the bearings.
    It is therefore alternatively or additionally possible that the motor spindle has a control loop for regulating the axial preload force, the fourth fiber-reinforced plastic material being acted upon by the axial preload force and, in combination with the further component, forms a measuring element and / or actuator of the control loop . The control loop is an integral part of the components of the motor spindle, which enables a motor spindle that is more simply constructed and operable.
    The object is also achieved by a method for regulating a storage device, in particular a storage device of a motor spindle described above for driving a tool that is directly clamped or held in a tool holder. First, a heat flow that occurs during operation is generated in a bearing device of the motor spindle. The heat flow is then introduced into an intermediate ring of the bearing device. A change in the shape of the intermediate ring, preferably a shortening of the intermediate ring, takes place by means of a temperature increase generated by the introduced heat flow. In addition, an axial preload force of the bearing device is reduced by shortening the intermediate ring. In principle, the structural design of the bearing device can be selected in such a way that any temperature-related change in shape leads to a reduction in the axial pretensioning force of the bearing device or is used. The method can thus preferably represent a negative feedback and thus a control loop for setting the axial preload force. This then takes place, as described above, by combining two differently adjusted fiber-reinforced plastic materials or a correspondingly adjusted fiber-reinforced plastic material and a further differently adjusted fiber-reinforced plastic material. A kinematic displacement of rolling elements and / or bearing rings of bearings of the bearing device causes an increase in the axial preload force. This increases the heat flow and the temperature of the intermediate ring increases. This reacts to the temperature increase by reducing its axial length, in particular relative to a corresponding axial length of the spindle shaft on which it is applied. This shortens a distance between the inner rings of the bearings of the bearing device, as a result of which the axial preload force is reduced. The lowering of the axial preload force caused by the contraction of the intermediate ring cannot prevent the kinematic displacement, but creates a free space that the corresponding bearing or the rolling elements can occupy, whereby this advantageously counteracts an otherwise forced tension and the associated increase in bearing friction can be. The control loop implemented in this way can be viewed as a proportional controller, with a control deviation remaining, however, compared to the non-controlled state, significantly lower temperatures and / or a significantly lower increase in the axial preload force despite very high speeds of up to 30,000, in particular 30,000 to 60,000, in particular about 60,000 revolutions per minute are possible. The regulation means that a sliding seat can be dispensed with and all bearings can be adjusted rigidly. With a bearing bore diameter of 40mm and bearings that are grease-lubricated for life in a rigid position, speeds of 40,000 rpm and more can be achieved, for example. In addition, the time behavior of the controller implemented in this way can be influenced by applying a cooling medium to the intermediate ring. The intermediate ring is therefore optionally cooled. The better the cooling of the intermediate ring, the shorter the time behavior of the heat flow from the bearings in the intermediate rings, which can be understood as a measuring section. As a result, the bearing device can be designed particularly advantageously without loose bearings and radially without intermediate sleeves. The first component lies in a force flow of the axial preload force. In one embodiment, the rotor arm, the spindle shaft and the outer intermediate ring are in the force flow of the axial preload force. The introduction of the heat flow thus takes place in at least one, preferably in several components to which the axial pretensioning force is applied. Alternatively, it can also be the intermediate ring, the rotor arm, the bearing shield, the spindle shaft and / or the outer intermediate ring.
    The features listed individually in the patent claims can be combined with one another in a technologically sensible manner and can be supplemented by explanatory facts from the description and by details from the figures, with further variants of the invention being shown. Further advantages emerge from the subclaims and the following description of a preferred exemplary embodiment.
    Brief description of the figures
    In the following, the invention is explained in more detail using an exemplary embodiment shown in the figures. Show it:<tb> <SEP> FIG. 1 is a longitudinal sectional view of a partially illustrated motor spindle;<tb> <SEP> FIG. 2 shows a detailed view of a partially illustrated motor spindle analogous to that illustrated in FIG. 1, in contrast to attachment parts integrated into a spindle shaft;<tb> <SEP> FIG. 3 shows a detailed view of a bearing device and a cooling device for cooling the bearing device of the motor spindle shown in FIG. 1;<tb> <SEP> FIG. 4 shows different detailed views of a partially illustrated tool interface of the motor spindle shown in FIG. 1;<tb> <SEP> FIG. 5 shows a basic illustration of a bearing device of a motor spindle analogous to the previously shown motor spindles to illustrate a speed-dependent regulation of an axial preload of the bearing device; and<tb> <SEP> FIG. 6 shows a longitudinal sectional view of a partially illustrated motor spindle according to the prior art.
    Description of preferred exemplary embodiments
    Before the invention is described in detail, it should be pointed out that it is not limited to the respective components of the device and the respective method steps, since these components and methods can vary. The terms used here are only intended to describe particular embodiments and are not used in a restrictive manner. If the singular or indefinite articles are used in the description or in the claims, this also refers to the majority of these elements, unless the overall context clearly indicates otherwise.
    Figure 6 shows a partially shown motor spindle 11 in a longitudinal sectional view. First, the mode of operation of a motor spindle 11 known as such is explained in more detail with reference to FIG. The known motor spindle 11 has a spindle shaft 19 made of a metallic material. Spindle shaft 19 is rotatably supported in a housing 25 by means of bearings 61 to 67 of a bearing device 23. The housing 25 also has a metallic material. A sliding seat 107 is provided on a third bearing 65 and a fourth bearing 67 and is supported on a metallic bearing plate 33 by means of a spring 105. As a result, a thermal linear expansion of the metallic material of the spindle shaft 19 can be compensated. The sliding seat 107 thus slides along the bearing plate 33 relative to the housing 25, depending on the change in length of the spindle shaft 19. For this purpose, O-rings 109 are provided for sealing between the sliding seat 107 and the bearing plate 33.
    The main difference to the motor spindles 11 according to the invention described below is that, compared to the metallic materials used in Figure 6, they have at least one specially adjusted fiber-reinforced plastic material, for example carbon fiber-reinforced plastic fiber material (CFRP material). At least two such materials can be provided particularly advantageously. In addition to further advantages explained in more detail with reference to FIGS. 1 to 5, in particular the floating bearing realized in the prior art by means of the sliding seat 107 can be omitted. Instead, a fixed bearing can be provided at a front end and a rear end of the spindle shaft 19. Due to the advantageous and / or differently adjusted fiber-reinforced plastic materials, precise and low-wear mounting of the spindle shaft 19 relative to the housing 25 is nevertheless possible.
    Figure 1 shows a partially shown motor spindle 11 according to the invention in a longitudinal sectional view. The motor spindle 11 has a spindle shaft 19. The spindle shaft 19 is rotatably supported in a housing 25 by means of a bearing device. For this purpose, the bearing device 23 has two bearing pairs with a first bearing 61, a second bearing 63, a third bearing 65 and a fourth bearing 67 between a front end and a rear end of the spindle shaft 19. The bearing pairs of the bearing device 23 are each spaced apart and prestressed by means of a spacer sleeve 35 seated on the spindle shaft 19 and an outer intermediate ring 81 arranged radially outside of the spacer sleeve 35.
    The spindle shaft 19 can be driven by means of a drive unit 17. The drive unit 17 is an electric machine with a stator 113, magnets 91 and sheet iron 93. The magnets 91 and sheet iron 93 are received on a rotor support 97 radially outside. The rotor arm 97 in turn sits directly on the spindle shaft 19. In addition, a cover in the form of a sleeve 95 is provided radially outside of the magnets 91. The bearing device 23 has two bearing plates 33 radially above the bearings 61 to 67. A cooling sleeve 79 is arranged radially above the end shields 33 and, together with the housing 25, provides a fluid path for guiding a second heat-conducting medium 43. The second heat-conducting medium 43 can be a liquid such as water. The second heat-conducting medium 43 circulates through the fluid path and serves to cool the motor spindle 11, in particular via the end shields 33 to cool the bearings 61 to 67 of the bearing device 23. In addition, one of these can be via the fluid path, which also runs radially above the drive unit 17 generated waste heat can be dissipated.
    The water fluid path, the cooling sleeve 79 and the housing 25 are part of a cooling device 29 of the motor spindle 11.
    To preload the bearing device 23 and to close the housing 25, the motor spindle 11 has a centrifugal disk 101 and a front cover 103 at a front end. The centrifugal disk 101 is mounted radially outside with the spindle shaft 19, for example by means of a press fit, a screw connection to the spindle shaft and / or another connection technology such as gluing, bonding and / or the like. The front cover 103 is mounted with a front one of the end shields 33. At a rear end of the motor spindle, a rear clamping cap 85 is similarly mounted on the spindle shaft 19. In addition, a rear cover 83 provided on a rear one of the end shields 33 is mounted. The fourth bearing 67 is supported on the rear cover 83 and the rear clamping cap 85. The first bearing 61 of the bearing device 23 is supported on the centrifugal disk 101 and the front cover 103.
    The motor spindle 11 also has a tool holder 13, shown only in FIGS. 4 a and b, for connecting a tool, indicated only by the reference number 15, to the spindle shaft 19 of the motor spindle 11. The tool holder 13 can be introduced into a shaft cone 47 in the spindle shaft 19 and coupled therewith there. For this purpose, a tool clamping device 115, which is partially shown and only indicated in FIGS. 4 a and b, is arranged within the spindle shaft 19. The motor spindle 11 thus has, with the tool clamping device 115 and the shaft cone 47, a tool interface 21 for the detachable, non-rotatable coupling of the tool holder 13 to the spindle shaft 19.
    As can also be seen in FIG. 1, a temperature sensor 99 is integrated into the spindle shaft 19 radially below the first bearing 61. Due to the integrated arrangement of the temperature sensor 99, a temperature of the bearing device 23, in particular an inner bearing ring 87 of the first bearing 61, can be measured particularly precisely and quickly. In addition, a further temperature sensor 99 is arranged in the front cover 103. This serves to measure a temperature of a first heat-conducting medium, in particular air, which can be pressed into the motor spindle 11 to cool the bearing device 23.
    The motor spindle 11 shown in Figure 1 has at least two differently adjusted with regard to a thermal conductivity property and / or a thermal expansion coefficient and / or a stiffness fiber-reinforced plastic materials, in particular CFRP. In particular, the spindle shaft 19, the housing 25, the end shields 33, the spacer sleeve 35, the shaft cone 47, a clamping tube 53 of the tool interface 21, a further intermediate ring 57 (not shown in FIG. 1) of a further bearing device 23, the outer intermediate ring 81 of the bearing device 23 , the sleeve 95 of the drive unit 17, the rotor arm 97 of the drive unit 17 made of a fiber-reinforced plastic material. At least two of them are set differently.
    FIG. 2 shows a further partially illustrated motor spindle 11 in a sectional view analogous to FIG. 1. Only the differences are discussed below. As an essential difference, components mounted on the spindle shaft such as the rotor carrier 97 and a holder 77 arranged radially inside the spindle shaft 19 are designed as integral components of the spindle shaft 19 in FIG. The holder 77 serves to support and mount the tool clamping device 115, not shown in detail. It can be seen that the first bearing 61 and the second bearing 63 from the front and the third bearing 65 and the fourth bearing 67 from the rear onto the spindle shaft 19, that is, can be mounted on both sides of the integrated rotor arm 97. In contrast to this, all four bearings 61 to 67 in the motor spindle 11 according to FIG. 1 are attached to the spindle shaft 19 from the rear.
    FIG. 3 shows a detailed view of the bearing device 23 on the first bearing 61 and the second bearing 63. The bearing device 23 can be cooled by means of a cooling device 29. The cooling device 29 has a first fiber-reinforced plastic material 27. This has direction-dependent thermal conductivity properties. More precisely, the spacer sleeve 35 and the end shield 33 have the first fiber-reinforced plastic material 27. The other components described above have a different fiber-reinforced plastic material. The cooling device 29 has two cooling circuits in which a first heat-conducting medium 41, here air, and the second heat-conducting medium, 43, here water, circulate. The flow of the first heat-conducting medium 41 and corresponding air fluid paths are symbolized by means of first arrows 117. The water fluid path and thus the flow of the second heat conducting medium 43 is symbolized by means of second arrows 119.
    As shown in Figure 3, 23 air fluid paths are introduced both in the end shield 33 and in the outer intermediate ring 81 of the bearing device. The first heat-conducting medium 41 flows in through a central fluid path and is thereby blown into a cavity remaining radially above the spacer sleeve 35 and correspondingly radially below the outer intermediate ring 81. As a result, the first heat-conducting medium 41 wets a surface 37 of the spacer sleeve 35. As can also be seen in FIG. 3, the surface 37 of the spacer sleeve 35 has an indentation 39 in the longitudinal sectional view. The indentation 39 is accordingly acted upon by the first heat-conducting medium 41.
    The spacer sleeve 35 is on both sides with the bearing inner rings 87 of the first bearing 61 and the second bearing 63 in a heat-transferring and force-transferring abutment contact. As symbolized by means of third arrows 121 in FIG. 3, a heat flow or heat transfer takes place from the inner bearing rings 87 to the spacer sleeve 35. The heat flow is conducted by means of heat-conducting fibers 31 introduced into the motor spindle 11 or the spacer sleeve 35 in a longitudinal direction. The heat-conducting fibers 31 can be made on a pitch basis and thus have particularly good thermal conductivity.
    Through the optionally provided indentation 39, the heat conducting fibers 31 are cut on a surface 37 or lead to this, in particular end just below the surface 37. This allows the heat transport symbolized by the third arrows 121 from the bearing inner rings 87 via the heat conducting fibers 31 to the surface 37 of the spacer sleeve 35 take place. On the surface 37, the frictional heat that occurs in the bearings 61 and 63 and is conducted there is absorbed by the first heat-conducting medium 41 and passed out of the motor spindle 11 via two exhaust air ducts.
    As can also be seen in FIG. 3, the end shield 33 also has the heat-conducting fibers 31. These enable a heat flow, which is also symbolized by third arrows 121, starting from bearing outer rings 89 of the first bearing 61 and the second bearing 63, which are arranged radially below the end shield 33, via the preferably metallic cooling sleeve 79 to the water fluid path, i.e. into the second heat-conducting medium 43.
    As a further optional special feature, the bearing plate 33 itself has two differently adjusted fiber-reinforced plastic materials. The heat conducting fibers 31 are arranged obliquely radially upwards between the water fluid path and the bearing outer ring 89 of the first bearing 61. Between the bearing outer ring 89 of the second bearing 63 and the water fluid path, these are aligned radially vertically upwards. As a result, the heat flow can be introduced more uniformly and directed or guided via the second heat-conducting medium 43. The advantages described above can be achieved in that at least two differently adjusted fiber-reinforced plastic materials, i.e. the first fiber-reinforced plastic material 27 of the end shield 33 and / or the spacer sleeve 35 and at least one further fiber-reinforced plastic material are provided.
    FIG. 4 shows, in four views A to D, a highly schematic detail of the tool clamping device 115 as well as a force distribution when clamping and unclamping the tool 15.
    In addition to components not shown in detail, the tool clamping device 115 has an ejecting device 75 for ejecting the tool holder in the form of the clamping tube 53.
    In Figure 4A, the tool holder 13 is shown in a clamped state. A hollow tapered shank of the tool holder 13 is seated in the shaft cone 47. The shaft cone 47 has a second fiber-reinforced plastic material 45. This has a comparatively higher rigidity in a longitudinal direction of the motor spindle than in a circumferential direction of the shaft cone 47 or the spindle shaft 19. This leads to a surface pressure of the hollow conical shaft of the tool holder 13 in the shaft cone 47, as shown in FIG. 4A, is comparatively smaller.
    FIG. 4B shows a state of the tool interface 21 in which the clamping tube 53 is displaced in the direction of the tool holder 13 and strikes within the hollow tapered shank. As a result, an ejection force 123 is introduced into the tool holder 13, which induces a counterforce 125 on the shaft cone 47. Due to the second fiber-reinforced plastic material 47, the induced counterforce is advantageously comparatively low, so that the ejection device 75 can be designed to be comparatively weaker. As a result, it can work with lower forces, in particular have comparatively smaller linear drives such as a hydraulic ram. As a result, a comparatively smaller motor spindle 11 can be provided. The ejection force 123 and the counter force 125 are shown in FIG. 4B.
    In the opposite case, that is, when clamping the tool holder 13 in the shaft cone 47 of the spindle shaft 19, a clamping force 127 is transmitted from the clamping tube 53 to the hollow cone shaft of the tool holder 13 by means of the tool clamping device 115. This is divided into a conical force 129 of the shaft cone 47 and a stop force 131 which occurs on a flat contact 49 at a front end of the spindle shaft 19. The plane contact 49 and the shaft cone 47 of the spindle shaft 19 form a double fit for the tool holder 13, the conical force 129 and the stop force 131 being induced at the double fit 51 or being introduced into the tool holder 13 as a counterforce to the clamping force 127. The ratio of the stop force 131 to the conical force 129 is preferably 70 to 90 to 10 to 30, preferably approximately 80 to 20. It can be seen that the conical force due to the second fiber-reinforced plastic material 45 of the shaft cone 47 is comparatively low, since this is a has comparatively low rigidity. As a result, the ejection force 123 is also lower, although good longitudinal vibration properties can still be achieved due to the comparatively higher rigidity in the longitudinal direction. Simultaneous optimization of both properties would not be possible with conventional metallic materials.
    The tensioning tube 53 has a third fiber-reinforced plastic material 55 with a comparatively high internal damping. As can be seen schematically in FIG. 4A, vibrations can be transmitted from the tool 15 via the tool holder 13 to the clamping tube 53. These can be reduced by the third fiber-reinforced plastic material 55, in particular by the comparatively high internal damping and the good density to rigidity ratio, and / or shifted in a natural frequency into a less disruptive higher frequency range.
    Figure 5 shows a greatly exaggerated in the longitudinal direction of the bearing device 23 with the bearings 61 to 67 to illustrate a device for regulating a preload 69 for preloading the bearings 61 to 67. The preload is in Figure 5 by means of arrows and their effect by means symbolized by dash-dotted lines. The bearing outer rings 89 of the second bearing 63 and of the third bearing 65 strike steps 71 of the respective end shields 33. As a result, the prestressing force 69 is introduced into this. The bearing outer rings 89 of the bearings 61 and 63 and the bearings 65 and 67 are each spaced apart from one another by an outer intermediate ring 81. The outer intermediate rings 81 are each arranged radially inside the end shields 33 between the respective bearing pairs. The inner bearing rings 87 of the respective bearing pairs are each spaced apart from one another by an intermediate ring 57 seated on the spindle shaft 19. In addition, the inner bearing rings 87 of the second bearing 63 and of the third bearing 65 each strike one side of the rotor arm 97.
    In order to set the axial pretensioning force 69, a distance between the steps 71 is less than a length of the rotor arm 97. The difference can be, for example, 30 μm, optionally between 25 and 35 μm. In addition, the intermediate rings 57 are each shorter than the outer intermediate rings 81. The difference can be approximately 10 μm, in particular between 8 and 12 μm. During operation of the motor spindle 11, i.e. with the spindle shaft 19 rotating at high speed, the rolling elements 111 of the bearings 61 to 67 tend radially outwards, which increases the preload force 69. This effect, known as kinematic displacement, has a comparatively higher effect at high speeds Bearing friction and thus a comparatively high heat flow, which is symbolized in FIG. 3 by means of the third arrows 121. As a result, the intermediate ring 57 heats up comparatively strongly.
    The respective intermediate ring 57 advantageously has a fourth fiber-reinforced plastic material 59. This has a coefficient of thermal expansion that differs from the other components and is, for example, less than zero. This means that a length of the intermediate rings 57 changes, in particular shortened, when the temperature increases relative to the other components. The other components, in particular the respective outer intermediate rings 81, the spindle shaft 19 and / or the rotor arm 97 have a different material, in particular fiber-reinforced plastic material, in particular with a thermal expansion coefficient of zero or approximately zero. As a result, the difference in length between the respective outer intermediate ring 81 and the intermediate ring 57 can be increased. This leads to a reduction in the preload force 69. The rotor arm 97 can also be understood as a spacer sleeve between the bearings 61 and 63 and the bearings 65 and 67. This can optionally additionally or alone have the fourth fiber-reinforced plastic material 59, in particular CFRP. As a result, it can also be used by setting the thermal expansion coefficient differently in order to set, control and / or regulate the preload or the axial preload force 69.
    The arrangement of the bearing device 23 shown in FIG. 5 therefore provides a controller for adjusting the preload force 69 of the bearings 61 to 67 as a function of the speed.
    Specifically, a speed-dependent heat flow is initially generated in the bearings 61 to 67 through the operation of the motor spindle 11. The heat flow is not only dependent on the speed, but also on the increase in the prestressing force 69 brought about by the kinematic displacement of the rolling elements 111. The pretensioning force 69 can therefore be viewed as the controlled variable of the control loop. This is measured indirectly by the heat flow symbolized by means of the third arrows 121 from the intermediate ring as the measuring element. In addition to the measuring element, this also represents the control element of the control loop. The intermediate ring 57 is shortened due to the properties of the fourth fiber-reinforced plastic material 59 by means of the temperature increase generated by the introduced heat flow relative to the other parts in the power flow. The shortening of the intermediate ring 57 causes a reduction in the axial pretensioning force 69 of the bearing device 23. The bearing device 23 shown in FIG. 5 is free of loose bearings and placed directly on the spindle shaft 19. In particular, the inner bearing rings 87 are held directly on the spindle shaft 19, in particular by means of a press fit. This is made possible by the advantageous different fiber-reinforced plastic materials, in particular by the regulation of the pretensioning force 69 explained in more detail in FIG.
    As shown in Figure 3, it is possible to cool the intermediate rings 57, which improves the timing of the control loop. In particular, this makes the measuring section of the control loop faster.
    According to a further aspect of the invention, the spindle shaft 19 has a fifth fiber-reinforced plastic material 73 radially below the bearings 61 to 67, more precisely radially below the bearing inner rings 87. This has a reduced rigidity in the circumferential direction of the spindle shaft 19 than in the longitudinal direction of the spindle shaft 19. This leads to a greater expansion of the spindle shaft 19 at high speeds. This is preferably increased to such an extent that the bearing inner rings 87 of the bearings 61 to 67 can be prevented from lifting off the spindle shaft 19. In addition, this effect can also be used to influence the pretensioning force 69 in addition to the influence by the control loop described above directly as a function of centrifugal force and thus as a function of the speed. The setting of the fifth fiber-reinforced plastic material 73 thus tensions the bearings 61 to 67 from radially below, optionally additionally depending on the speed. As a result, a pretensioning force 69 that is virtually constant over the entire speed range of the motor spindle can be brought about.
    The invention is not limited to the individual exemplary embodiments. Rather, the individual exemplary embodiments can be combined to form new designs. In particular, the advantages of the cooling and regulation described above can be combined with one another in one component, for example.
    List of reference symbols
    11 motor spindle 13 tool holder 15 tool 17 drive unit 19 spindle shaft 21 tool interface 23 bearing device 25 housing 27 first fiber-reinforced plastic material 29 cooling device 31 thermal fiber 33 bearing shield 35 spacer sleeve 37 surface 39 indentation 41 first thermal conductive medium 43 second thermal conductive medium 45 second fiber-reinforced plastic material 47 wave cone 49 plane contact 51 Double fit 53 clamping tube 55 third fiber-reinforced plastic material 57 intermediate ring 59 fourth fiber-reinforced plastic material 61 first bearing 63 second bearing 65 third bearing 67 fourth bearing 69 preload force 71 step 73 fifth fiber-reinforced plastic material 75 ejector 77 holder 79 cooling sleeve 81 outer intermediate ring 83 rear cover 85 rear clamping cap 87 bearing inner ring 89 outer bearing ring 91 magnets 93 sheet iron 95 sleeve 97 rotor arm 99 temperature sensor 101 flinger 103 front cover 105 spring 107 sliding seat 109 O-ring 111 W älzkörper 113 Stator 115 Tool clamping device 117 first arrow 119 second arrow 121 third arrow 123 ejection force 125 counterforce 127 clamping force 129 cone force 131 stop force
    权利要求:
    Claims (11)
    [1]
    1. Motor spindle (11) for driving a tool (15) clamped directly or held in a tool holder (13), with:- a spindle shaft (19) driven by a drive unit (17),- A tool interface (21) for the detachable, rotationally fixed coupling of the tool holder (13) to the spindle shaft (19),- a bearing device (23) for rotatably mounting the spindle shaft (19),- A housing (25) in which the spindle shaft (19), the bearing device (23) and the drive unit (17) are received,characterized in that the motor spindle (11) has a control loop which is structurally integrated into the motor spindle and has at least two fiber-reinforced plastic materials set differently in terms of stiffness, thermal conductivity and / or coefficient of thermal expansion.
    [2]
    2. Motor spindle according to claim 1, characterized in that a first (27) of the fiber-reinforced plastic materials is arranged between the bearing device (23) and a cooling device (29) which has a direction-dependent thermal conductivity which occurs in a direction between the bearing device ( 23) and the cooling device (29) is increased.
    [3]
    3. Motor spindle according to claim 2, characterized in that the first fiber-reinforced plastic material (27) has aligned heat-conducting fibers (31), the heat-conducting fibers (31) running essentially between the bearing device (23) and the cooling device (29).
    [4]
    4. Motor spindle according to one of claims 2 or 3, characterized in that a bearing plate (33) and / or a spacer sleeve (35) of the bearing device (23) comprises the first fiber-reinforced plastic material (27), wherein the heat conducting fibers (31) are cut on a surface (37) or at least run towards the surface (37), the spacer sleeve (35) having an indentation (39) in which the heat-conducting fibers end, the indentation (39) for the removal of heat with a Heat conducting medium (41) can be acted upon.
    [5]
    5. Motor spindle according to one of the preceding claims, characterized in that a second (45) and / or fifth (73) of the fiber-reinforced plastic materials is / are arranged at the tool interface (21) and / or radially below the bearing device (23), which have a comparatively higher rigidity in a longitudinal direction of the spindle shaft (19) of the motor spindle (11) than in a circumferential direction of the spindle shaft (19).
    [6]
    6. Motor spindle according to claim 5, characterized in that a shaft cone (47) of the spindle shaft (19) which cooperates with the tool holder (13) has the second fiber-reinforced plastic material (45), the spindle shaft (19) having one with the tool holder (13) co-operating planar system (49), the planar system (49) and the shaft cone (47) acting as a double fit (51) for the tool holder (13), with a clamping force (127) for clamping the tool holder (13) in a ratio of 90 to 70 to 10 to 30, preferably about 80 to 20, distributed over the planar system (49) to the wave cone (47).
    [7]
    7. Motor spindle according to one of the preceding claims, characterized in that a clamping tube (53) of the tool interface (21) has a third (55) of the fiber-reinforced plastic materials, the third fiber-reinforced plastic material (55) having a comparatively high internal damping.
    [8]
    8. Motor spindle according to one of the preceding claims, characterized in that a fourth (59) of the fiber-reinforced plastic materials has a thermal expansion coefficient different from another component of the motor spindle (11) and / or an intermediate ring (57) of the bearing device (23) the fourth fiber-reinforced Comprises plastic material (59).
    [9]
    9. Motor spindle according to claim 8, characterized in that the fourth fiber-reinforced plastic material (59) and / or the intermediate ring (57) is arranged between two bearings (61, 63; 65, 67) of the bearing device (23), via this / an axial preload force (69) can be transmitted to the bearings (61, 63; 65, 67) and a heat flow from the bearings (61, 63; 65, 67) into the fourth fiber-reinforced plastic material (59) and / or into the intermediate ring (57) can be introduced, an increase in temperature of the fourth fiber-reinforced plastic material (59) and / or of the intermediate ring (57) causing a reduction in the axial pretensioning force (69).
    [10]
    10. Motor spindle according to claim 8 or 9, characterized in that the motor spindle has a control loop for regulating the axial prestressing force (69), the fourth fiber-reinforced plastic material (59) being acted upon by the axial prestressing force (69) and in combination with the other Component forms a measuring element and / or actuator of the control loop.
    [11]
    11. The method for regulating a storage device (23), in particular a storage device of a motor spindle (11) according to one of the preceding claims, characterized by:- Generating a heat flow (121) of a bearing device (23) of the motor spindle (11) occurring during operation,Introducing the heat flow (121) into at least one first component of the bearing device (23) which is subjected to an axial pretensioning force and has a fiber-reinforced plastic material, in particular into at least one component of the bearing device (23) from the group: the intermediate ring (57), a rotor carrier (97), the end shield (33), the spindle shaft (19), an outer intermediate ring (81),- changing a length or shape of the first component by means of a temperature increase generated by the introduced heat flow (121) relative to a further component of the bearing device (23) having a further fiber-reinforced plastic material,- Controlling the axial prestressing force (69) by means of changing the length or shape of the first component relative to the further component.
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    同族专利:
    公开号 | 公开日
    DE102019203078A1|2020-09-10|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US5018915A|1989-09-08|1991-05-28|Toshiba Kikai Kabushiki Kaisha|Spindles of machine tools|
    DE19726341A1|1997-06-20|1999-01-07|Paul Mueller Gmbh & Co Kg|Shaft of a motor driven spindle|
    EP3100805B1|2011-07-20|2018-09-26|NSK Ltd.|Spindle device|
    DE102013109947B4|2013-09-11|2020-05-14|FISCHER Präzisionsspindeln GmbH|spindle|
    EP3069848B1|2015-03-20|2019-11-20|North Thin Ply Technology Sarl|Method for forming a fiber-reinforced composite structure|
    DE102017120523A1|2017-09-06|2019-03-07|Technische Universität Darmstadt|Spindle and a method for producing a spindle|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE102019203078.5A|DE102019203078A1|2019-03-06|2019-03-06|Motor spindle with differently adjusted fiber-reinforced plastic materials and method for controlling a motor spindle|
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