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    • 专利摘要:
    A machine tool for machining gears has: a workpiece spindle (16) to drive a workpiece (18) to rotate about a workpiece axis (C1), and a tool spindle to rotate a tool (12) about a tool axis (B ) to drive. With an infeed slide (5), a radial axial distance between the tool axis (B) and the workpiece axis (C1) can be changed along a radial infeed direction (X), the radial infeed direction (X) at an angle of 60 ° to 120 ° to the workpiece axis ( C1), in particular perpendicular to the workpiece axis (C1). An axial slide (7) is used to change a relative feed position between the tool spindle and the workpiece spindle along the workpiece axis. The axial slide is guided along an axial guidance direction (Z ') which is inclined by an angle of inclination (ψ) with respect to the workpiece axis, the angle of inclination (ψ) being between 0.1 ° and 30 °. The axial guidance direction (Z ') runs in a common plane with the workpiece axis (C1) and the radial infeed direction (X).
    公开号:CH716649B1
    申请号:CH01094/20
    申请日:2020-09-04
    公开日:2021-10-15
    发明作者:Müller Michel
    申请人:Reishauer Ag；
    IPC主号:
    专利说明:

    TECHNICAL AREA
    The present invention relates to a machine tool for machining gears, a method for their operation and a computer program product for executing the method.
    STATE OF THE ART
    In gearing technology, straight or helical gears are often produced, the flank lines of which are modified to be crowned in width. The size of the modifications is often only in the range below a few tens of micrometers. Toothings modified in this way have particular advantages in terms of load behavior and noise generation.
    For the production of broad crowned modified gears, a method has been proposed in the prior art in which the center distance between workpiece and tool is continuously changed along a radial feed direction during a machining stroke. For this purpose, it was proposed in the prior art to execute a movement along the radial feed direction during the machining stroke, which initially increases the center distance, comes to a standstill in the middle of the toothing and then reduces the center distance again while the tool is continuously advanced parallel to the workpiece axis .
    This method is problematic in that a direction reversal of the radial infeed movement takes place in the course of the machining stroke. A large number of components are involved in the radial infeed movement, between which elastic forces and frictional forces occur. When the direction is reversed, there is a transition from sliding friction to static friction, particularly at the seals involved. As a result, after the direction reversal, the static friction must first be overcome before the sliding friction sets in again. As a result, the radial infeed movement at the reversal point cannot completely follow the setpoints and comes to a complete standstill for a certain period of time until the forces that act overcome the static friction force again. This effect can lead to undesired deviations of the flank shape from the specifications.
    In addition, the machining forces may be relatively small, particularly in the case of finishing operations in which only a very small allowance is removed. This can lead to a load change when the direction is reversed along the radial infeed direction, which leads to an additional undesirable reversal effect due to the finite stiffness of the components involved.
    In addition, in the case of very slow radial infeed movements, friction effects can also occur independently of the reversal of direction, which, together with elastic forces, can lead to friction-induced vibrations. Such effects also arise when making modifications other than broad-crowned modifications, e.g. conical modifications.
    These effects can be counteracted by various measures. In particular, particularly low-friction guide and drive components can be used to reduce the frictional effects. To reduce the reverse effects, the rigidity of the guide and drive components can be increased or optimized together with the damping. Finally, these effects can also be counteracted through control technology. However, all these measures only lead to a weakening of the problems mentioned, but cannot completely eliminate the problems.
    DE 10 2012 016515 A1 discloses a gear shaping machine, the shaping head slide of which is attached to a machine frame in an inclined position. In this way, a simultaneous displacement of the slotting tool in the horizontal direction is achieved by a displacement in the vertical direction in order to lift the slotting tool off the workpiece on the return stroke. The generation of modifications is not addressed.
    US 2016/176010 A1 discloses a generating grinding machine with two workpiece spindles and one tool spindle. The tool spindle is mounted displaceably along a linear guide which extends parallel to a horizontal inclined axis. The workpiece spindles are at the same vertical horizontal distance from the horizontal inclined axis. In a horizontal projection, the tool rotation axis forms an acute angle to the horizontal inclined axis. This avoids collisions between the tool spindle and the workpieces. The generation of modifications is not addressed here either.
    DISCLOSURE OF THE INVENTION
    It is an object of the present invention to specify a gear cutting machine which enables the production of modified tooth flanks with greater precision.
    This object is achieved by a machine tool for machining gears according to claim 1. Further embodiments are given in the dependent claims.
    A machine tool for machining gears is proposed. This has: a workpiece spindle to drive a workpiece to rotate about a workpiece axis; a tool spindle to drive a tool (machining tool) to rotate about a tool axis, and an axial slide with which a relative feed position between the tool spindle and the workpiece spindle is variable along the workpiece axis.
    According to the invention, the axial slide is guided along an axial guidance direction which is inclined by an angle of inclination with respect to the workpiece axis. The amount of the angle of inclination assumes a value between 0.1 ° and 30 °, preferably between 0.1 ° and 15 °, particularly preferably between 0.1 ° and 3 °. In some embodiments, the amount of the angle of inclination assumes a value between 0.5 ° and 30 °, between 0.5 ° and 15 °, or between 0.5 ° and 3 °.
    The axial slide carries either the workpiece spindle or the tool spindle. Due to the inclined guidance of the axial slide, the radial distance between the tool axis and the workpiece axis changes when the axial slide moves along the axial guidance direction. This makes it possible to manufacture toothings with tooth trace modifications without the need to reverse the direction of the radial infeed movement while the toothing is being machined. The problems mentioned, which arise when the direction is reversed, are avoided in this way. In addition, it is possible to produce even the smallest tooth trace modifications without causing disruptive friction effects.
    In addition, the machine tool has a feed slide with which the axial distance between the tool axis and the workpiece axis can also be changed along a feed direction. This infeed can take place independently of the movement along the axial guidance direction. It is superimposed on the change in the center distance due to the inclined guidance of the axial slide. Accordingly, simultaneous movements of the axial slide and the feed slide occur during the machining of the tooth flanks.
    The infeed direction can, but does not have to, run perpendicular to the workpiece axis. It is referred to below as the “radial infeed direction”, even if this direction does not necessarily run exactly radially to the workpiece axis, that is, not necessarily exactly perpendicular to the workpiece axis. According to the claim, the radial infeed direction forms an angle with the workpiece axis in the range from 60 ° to 120 °.
    According to the claim, the axial guidance direction runs in a common plane with the workpiece axis and the radial infeed direction. The angle of inclination can be positive or negative in this plane, i.e. the axial guidance direction (viewed from the machine bed) can be away from the workpiece axis or inclined towards it.
    The tool spindle is preferably arranged directly or indirectly (i.e. via further slides and / or swivel bodies) on the axial slide, that is to say the tool spindle executes movements along the inclined axial guide direction with respect to a machine bed of the machine tool. In this case, the axial slide forms a tool carrier. However, it is also conceivable that the workpiece spindle is mounted directly or indirectly on the axial slide, that is to say that the workpiece spindle executes movements along the inclined axial guide direction with respect to the machine bed.
    In particular, the following axis arrangement can be present: the feed slide can be slidably guided along the radial feed direction on the machine bed and form a tool carrier, and the axial slide can then be arranged on the feed slide along the axial guide direction.
    In advantageous embodiments, the tool spindle can be pivoted about a pivot axis with respect to the axial slide. For this purpose, the machine tool can have a swivel body. The swivel body can in particular be arranged on the axial slide. If the tool is a grinding tool, the swivel body is also known as a grinding head. The pivot axis preferably runs parallel to the radial infeed direction or perpendicular to the workpiece axis. However, it can also run at an angle to the radial infeed direction which deviates from 0 °, this angle preferably being between 0 ° and 30 ° in terms of magnitude. The pivot axis can also run at an angle to the workpiece axis which deviates from 90 °, this angle preferably being in the range from 60 ° to 120 °. In particular, the pivot axis can run perpendicular to the axial guidance direction. It is advantageous if the pivot axis lies in a plane that is spanned by the workpiece axis and the axial guidance direction.
    In one embodiment which is particularly suitable for continuous generating grinding, the tool spindle can be displaced relative to the axial slide along a shift direction which runs parallel to the tool axis. For this purpose, the machine tool can have a shift slide. The shift slide can in particular be attached to the swivel body in such a way that it can be displaced relative to the swivel body along the shift direction. The shift direction is preferably perpendicular to the pivot axis about which the tool spindle can be pivoted. In some embodiments, it also runs perpendicular to the radial infeed direction.
    The present invention also provides a method for machining tooth flanks of a workpiece with a machine tool of the type specified above. The method has: Execution of simultaneous movements between the tool spindle and the workpiece spindle along the inclined axial guidance direction (so-called machining stroke) and the radial infeed direction (so-called infeed movement), while a tool clamped on the tool spindle is in a machining engagement with the workpiece clamped on the workpiece spindle is located, the movement taking place along the inclined axial guidance direction with an axial guidance speed and the movement taking place along the radial infeed direction with a radial infeed speed.
    The machine accordingly preferably has a control device which is designed to control the machine tool so that it executes corresponding simultaneous movements between the tool spindle and the workpiece spindle along the inclined axial guidance direction and the radial feed direction.
    The sign of the axial guidance speed preferably does not change during a machining stroke. The sign of the radial infeed speed also preferably does not change during a machining stroke. It is advantageous if the amount of the radial infeed speed does not fall below a predetermined threshold value during a machining stroke (and to this extent during machining of each individual tooth flank). This avoids adverse effects in the radial feed movement. As a result, tooth trace modifications can be manufactured with much greater accuracy than in the prior art.
    Particular advantages arise when the radial feed speed and the axial guide speed are in a time-variable relationship. In particular, these speeds can be in a variable relationship in such a way that the radial infeed speed does not change its sign during a machining stroke (and in so far during the machining of a tooth flank), while a resulting movement between the tool spindle and the workpiece spindle along the radial infeed direction has a speed which changes its sign during the machining of the tooth flanks (or during a machining stroke). As a result, toothing that is modified with a wide crown can be manufactured without the disadvantages of the prior art described above occurring.
    The method can include: measuring position variables along the radial infeed direction and the inclined axial guidance direction; and transforming the measured position variables into transformed position variables along the radial feed direction and an axial feed direction running parallel to the workpiece axis.
    The method can also have: generating control commands for a movement of the tool spindle relative to the workpiece spindle along an axial feed direction running parallel to the workpiece axis; and transforming the generated control commands into transformed control commands for a simultaneous movement of the tool spindle along the inclined axial guidance direction and the radial feed direction.
    These measures make it possible to control the machine with a control device which is designed for machines whose axial guidance direction runs parallel to the workpiece axis direction.
    The control device of the machine tool can accordingly comprise at least one of the following transformation devices: a first transformation device to convert position variables measured along the radial feed direction and the inclined axial guide direction into transformed position variables along the radial feed direction and an axial feed direction running parallel to the workpiece axis to transform; and a second transformation device to transform control commands for a movement of the tool spindle relative to the workpiece spindle along an axial feed direction running parallel to the workpiece axis into transformed control commands for a simultaneous movement of the tool spindle along the inclined axial guide direction and the radial feed direction.
    The machine tool can in particular be designed for one of the following methods: continuous generating grinding, partial generating grinding, discontinuous or continuous profile grinding, gear honing, hobbing or generating skiving. For this purpose, a corresponding tool can in particular be clamped on the tool spindle. The control device can be designed to control the machine tool in such a way that it executes the respective process-typical movements of the tool spindle and the workpiece spindle.
    The machine tool can have a dressing device with a dressing tool. The control device can then be designed to dress the tool, in particular a grinding worm, with the dressing tool while generating movements along the inclined axial guidance direction. During dressing, relative movements are thus generated between the tool and the dressing tool along the inclined axial guidance direction while the tool is in engagement with the dressing tool. As a result, similar advantages can be achieved when dressing as when machining gears.
    In particular, the control device can be designed to align the tool spindle with its pivot axis relative to the axial slide in such a way that the tool axis runs in or parallel to a plane that is spanned by the axial guidance direction and the radial feed direction. This position of the tool spindle is referred to below as the dressing position. The specified choice of the dressing position is particularly advantageous when the tool is a grinding worm. In this way, during the dressing process, the grinding worm can easily be moved along its longitudinal axis, i.e. along the tool axis, along the inclined axial guidance direction relative to the dressing tool, in order to be able to dress the grinding worm over its entire width. The axial slide can be used for this. If the tool spindle is mounted on a shift slide, the shift slide can also be used as an alternative or in addition, depending on the embodiment.
    The dressing device can have a dressing spindle which is designed to drive the dressing tool to rotate about a dressing spindle axis. The dressing spindle is preferably pivotable about at least one pivot axis in order to bring the dressing tool into engagement with the machining tool when the tool spindle is in the above-specified dressing position. For this purpose, the dressing device can have a corresponding swivel body. The pivot axis of the dressing spindle preferably runs transversely to the axial feed direction, in particular at an angle of 60 ° to 120 ° to the axial feed direction, and transversely to the workpiece axis, preferably at an angle of 60 ° to 120 ° to the workpiece axis, in particular perpendicular to it. If the workpiece axis runs vertically in space, the pivot axis of the dressing spindle preferably runs horizontally.
    The dressing device can be attached together with the at least one workpiece spindle on a movable tool carrier, or it can be arranged in a stationary manner relative to the machine bed.
    The present invention also provides a computer program product with a computer program. The computer program comprises commands which cause a control device in a machine tool of the type explained above, in particular one or more processors of the control device, to execute the method explained above for machining tooth flanks of a workpiece. The computer program can be stored in a suitable storage device.
    The computer program can be stored on a computer-readable medium. The medium can be a non-volatile medium such as flash memory, CD, hard disk, etc.
    BRIEF DESCRIPTION OF THE DRAWINGS
    Preferred embodiments of the invention are described below with reference to the drawings, which are only used for explanation and are not to be interpreted as restrictive. The drawings show: FIG. 1 a schematic perspective view of a generating grinding machine according to a first embodiment; FIG. 2 shows a schematic side view of the generating grinding machine from FIG. 1; FIG. 3 shows a diagram to illustrate a coordinate transformation when machining a cylindrical spur gear; 4 shows a schematic side view of a spur gear with toothing modified to form a broad crown; FIG. 5 shows a diagram to illustrate a coordinate transformation when machining a spur gear according to FIG. 4; FIG. 6 shows a schematic block diagram of functional units for controlling the axial feed movement; 7 shows a schematic side view of a generating grinding machine according to a second embodiment; 8 shows a schematic side view of a generating grinding machine according to a third embodiment; and FIG. 9 shows a schematic side view of a generating grinding machine according to a fourth embodiment.
    DESCRIPTION OF PREFERRED EMBODIMENTS
    Exemplary structure of a generating grinding machine
    In FIGS. 1 and 2, a generating grinding machine 1 according to a first embodiment is shown as an example of a machine tool for machining gears. The machine has a machine bed 4 on which a tool carrier 5 is guided displaceably along a radial infeed direction X by means of linear guides 6. The tool carrier 5 carries an axial slide 7 which is guided along an axial guidance direction Z ′ so as to be displaceable with respect to the tool carrier 5. A grinding head 9 is mounted on the axial slide 7 and can be pivoted about a pivot axis A running parallel to the X direction in order to adapt to the helix angle of the toothing to be machined. The grinding head 9 in turn carries a shift slide on which a tool spindle 11 can be displaced along a shift direction Y. The shift direction Y runs perpendicular to the pivot axis A and thus also perpendicular to the X direction, but not necessarily perpendicular to the Z 'direction. A fine machining tool in the form of a helical profiled grinding wheel (grinding worm) 12 is clamped on the tool spindle 11. The grinding worm 12 is driven by the tool spindle 11 to rotate about a tool axis B. The tool axis B runs parallel to the Y direction.
    The machine bed 4 also carries a pivotable workpiece carrier 15 in the form of a rotating tower, which can be pivoted about a vertical axis C3 between at least two positions. Two identical workpiece spindles 16, 17 are mounted diametrically opposite one another on the workpiece carrier 15. The workpiece spindle 16 arranged on the left in FIG. 2 is in a machining position in which a workpiece 18 clamped on it can be machined with the grinding worm 12. For this purpose, this workpiece spindle drives the workpiece 18 to rotate about a vertical first workpiece axis C1. The other workpiece spindle 17, offset by 180 °, is located in a workpiece change position, in which a finished workpiece 19 can be removed from this spindle and a new blank can be clamped. The axis of the workpiece spindle in this position is referred to as the second workpiece axis C2.
    In addition, a dressing device 13, only indicated symbolically, with a dressing tool 14 is mounted on the rotating tower. This is used to dress the grinding worm 12.
    All driven linear and rotary axes of the generating grinding machine 1 are digitally controlled by a machine control with control panel 2 and axis modules 3. The axis modules 3 provide control signals at their outputs for one machine axis each (i.e. for at least one actuator that is used to drive the machine axis in question, such as a servo motor).
    Machining a workpiece
    In order to process a still unprocessed, pre-toothed workpiece (blank) 19, the workpiece 19 is clamped by an automatic workpiece changer on that workpiece spindle 17 which is in the workpiece changing position. The workpiece change takes place parallel to the machining of another workpiece 18 on the other workpiece spindle 16, which is in the machining position. When the new workpiece 19 to be machined is clamped and the machining of the other workpiece 18 is completed, the workpiece carrier 15 is pivoted 180 ° about the C3 axis, so that the spindle with the workpiece to be newly machined reaches the machining position. Before and / or during the pivoting process, a centering operation is carried out with the aid of a centering probe, not shown in the drawing and arranged on the workpiece carrier 15. For this purpose, the workpiece spindle 17 is set in rotation, and the position of the tooth gaps of the workpiece 19 is measured with the aid of the centering probe. The rolling angle is determined on this basis.
    When the workpiece spindle 17, which carries the workpiece 19 to be machined, has reached the machining position, the workpiece 19 is brought into engagement with the grinding worm 12 by displacing the tool carrier 5 along the X axis. The workpiece 19 is now machined by the rotating grinding worm 12 in rolling engagement. The machine executes coordinated movements along the axes X, Y and Z '. Machining can take place in one or more axial machining strokes. During each machining stroke, the machine executes a movement along the Z'-axis, the speed of which does not change its sign.
    In parallel with the machining of the workpiece, the finished workpiece 18 is removed from the other workpiece spindle 16, and another blank is clamped onto this spindle.
    Axis directions
    In addition to the directions X, Y and Z 'already mentioned, a further direction Z is defined. By definition, this runs parallel to the workpiece axis C1, i.e. to the axis of rotation of the workpiece that is in the machining position. As a result of the machining stroke along the Z 'axis, the position of the tool relative to the workpiece is continuously changed along the Z direction during machining of the workpiece, in order to machine the toothing over the entire width of the workpiece. This is called the axial feed, and the Z direction is therefore also called the axial feed direction.
    In the prior art, the axial guidance direction Z ', i.e. the direction along which the axial slide 7 is slidably guided, usually coincides with the axial advance direction Z. In the present machine, however, these directions differ from one another. Specifically, the Z 'direction runs within a plane that is spanned by the X direction and the Z direction, and is inclined by an angle ψ with respect to the Z direction. In terms of amount, ψ is between 0.1 ° and 30 °, in particular between 0.1 ° and 30 °, preferably between 0.1 ° and 15 °. A relatively small angle can be sufficient, e.g. between 0.1 ° and 3 °, in particular between 0.5 ° and 3 °.
    For the presently proposed arrangement of the directions X, Y, Z, Z ', A, B and C1, the following applies overall: lies in the X-Z or X-C1 plane
    The symbol “is parallel to”, the symbol “is not parallel to”, the symbol ⊥ “is perpendicular to” and the symbol “is at an angle not equal to 0 ° and not equal to 90 °”.
    Coordinate transformation
    The machine control normally calculates the corresponding control commands in the X, Y, Z coordinate system for a desired flank shape of the toothing. In the present machine, a pure feed movement along the Z direction requires simultaneous movements along the X and Z 'directions. In order to be able to operate the present machine without having to rewrite all machine programs, the machine control is advantageously designed in such a way that it converts the usual feed commands for movements along the Z direction into transformed control commands for simultaneous movements along the X and Z 'directions transformed.
    This is explained below with reference to FIG. It is assumed that the tool should move at a constant speed vZ along the Z direction and with a constant center distance to the workpiece from a starting position with coordinates x = x0, z = z0 to an end position with coordinates x = x0, z = z1. The corresponding movement profile 31 is illustrated in part (a) of FIG. 3. Such a movement profile is selected when a cylindrical spur gear is to be machined without its flanks being modified by additional axis movements.
    In order that such a movement profile can be generated in the present machine, the drives must be operated simultaneously along the directions X and Z '. This is illustrated in part (b) of FIG. 3. As can be seen from this diagram, the axial slide 7 moves continuously along the positive Z 'direction, while the tool carrier 5 moves continuously in the negative X direction (ie to the right in FIG. 2) in order to incline the axial guidance direction Z 'to compensate. Overall, the tool carrier 5 is moved from one location to a location at a constant speed along the Z 'direction, while it is moved at a constant speed along the X direction from the location x0 to a location x1. The following applies to the start and end positions:
    Correspondingly, the following applies to the speeds along the Z 'direction and vX along the X direction:
    The corresponding movement profile 31 'along the X and Z' directions is illustrated in part (b) of FIG.
    On this basis, it is easily possible to transform feed commands along the Z direction into transformed feed commands along the X and Z 'directions.
    If the tool simultaneously executes a shift movement along the Y-axis, this movement remains unaffected by the transformation into the coordinate system X, Y, Z '. A swivel movement around the A-axis, for example, if it was carried out during machining, or a change in the pitch coupling angle to generate additional rotary movements between the workpiece and the tool remain unaffected.
    Assuming that the coordinate zero points of the Z and Z 'directions coincide, location coordinates x, y, z in the coordinate system X, Y, Z can thus be as follows in location coordinates x', y ', z' in the coordinate system X. 'Y, Z' are transformed:
    The inverse transformation T <-1> is to be used when measurements are made with a measuring system that is arranged along the X and Z 'directions and the X and Z coordinates of the tool carrier 5 on the basis of such measurements should be determined. This inverse transformation may be necessary in order to transfer the measured coordinates to the machine control in the required form. In this case the coordinates x, y, z in the coordinate system X, Y, Z are to be calculated as follows from the coordinates x ', y', z 'in the coordinate system X, Y, Z':
    Creation of a broad-crowned modification
    In the following, the generation of a broad-crowned modification on a cylindrical spur gear is explained with reference to FIGS.
    A spur gear 32 modified to have a crowned width is shown symbolically in FIG. The teeth of the spur gear are thicker in the middle than at the ends along the width direction (this is the Z direction during machining), and the tooth flanks of the tooth flanks are correspondingly curved. Sometimes, for manufacturing reasons, the tip diameter in the center of the spur gear is also larger than at the edges, so that the spur gear also has a barrel-shaped outer contour. In FIG. 4, the barrel-shaped outer contour is drawn in extremely exaggerated in order to be able to explain the principle more simply. In reality, such modifications are usually only in the range of a few micrometers and cannot be seen with the naked eye.
    It is known from the prior art to produce a broadly crowned modified spur gear by superimposing a slow radial feed movement in the X direction during the feed movement along the Z direction. Such a movement profile 33 is illustrated in part (a) of FIG. 5. An infeed movement along the X direction is superimposed on a uniform axial feed movement at constant speed along the Z direction. This initially has a positive speed (coordinate x increases), which continues to decrease until the infeed speed in the middle of the width of the toothing becomes zero and its sign changes (i.e. coordinate x decreases again).
    Very small radial infeed speeds are problematic because of the unavoidable frictional effects. Reversing the direction of the infeed movement is also problematic because the elements involved in the guidance along the X direction show an unavoidable reversal effect.
    In the present machine, a reversal of the infeed movement when generating modifications is avoided, and the infeed speed never falls below a certain minimum speed while the toothing is being machined, provided the required amount of crowning is not too great. This is illustrated in part (b) of FIG. 5, in which the resulting movement profile 33 'is illustrated. The tool carrier 5 moves continuously in the negative X direction in order to compensate for the inclination of the Z 'direction. The movement for generating the modification is superimposed on this continuous basic movement. The amount of the speed of the superimposed movement is always lower than the speed of the basic movement, so that during machining of the toothing there is never a reversal of direction and the speed never falls below a certain minimum.
    Functional units for controlling the axial feed movement and radial feed movement
    FIG. 6 schematically illustrates various functional units that are used in the context of generating the axial feed movement along the Z direction and the radial feed movement along the X direction. Position sensors 41, 42 detect the positions x ', z' of the tool carrier 7 along the X and Z 'directions. A first transformation device 43 transforms these positions in the coordinate system X, Y, Z 'into the positions x and z in the coordinate system X, Y, Z by using the inverse transformation T <-1> and transfers these actual values to a control computer 44 of the machine control . The control computer 44 generates control signals Ax, Az, which correspond to setpoint values for the positions of the tool carrier 7 in the X, Y, Z coordinate system. A second transformation device 45 transforms these control signals into transformed control signals Ax ', Az' in the coordinate system X, Y, Z 'and transfers these transformed control signals to the axis modules 3 of the machine control.
    Use in dressing
    It is known from the prior art to produce modifications on the grinding worm flanks during dressing by means of corresponding axis movements in order to transfer these to the workpiece flanks during the subsequent machining in the diagonal process. For this purpose, it is known to bring a spatially fixed dressing device with a rotating dressing wheel into engagement with the grinding worm and to generate the necessary movements with the machine axes X and Y.
    Another dressing strategy is possible with the present machine. For this dressing strategy, the grinding worm is rotated around the A axis so far that the shift axis Y and the tool axis B are perpendicular, i.e. run along the Z direction. The dressing device is aligned accordingly.
    In FIG. 2, the dressing device 13, which is only shown symbolically, is indicated by the dashed line. The dressing device is mounted on the workpiece carrier (rotating tower) 15. By pivoting the turret through 90 °, it can be brought into a position in which it faces the grinding worm 12. The dressing device 13 comprises a dressing spindle with a dressing disk 14 mounted on it and driven to rotate. The dressing spindle is mounted on a swivel body 21. This is pivotably connected to the workpiece carrier in such a way that the dressing wheel 14 can be aligned in the direction of the worm flights and relative to the grinding worm profile. The corresponding pivot axis runs perpendicular to the workpiece axes C1, C2 and horizontally in space. In FIG. 2, the corresponding pivot axis runs perpendicular to the plane of the drawing. In addition, the dressing spindle can be pivoted about a further pivot axis, which also runs horizontally in space and is perpendicular to the aforementioned pivot axis. In FIG. 2, this additional pivot axis runs horizontally in the plane of the drawing. With this additional pivot axis, for example, the profile angle can be changed when dressing.
    The necessary dressing movements along the tool axis B are now not generated with the shift slide along the Y-axis as usual, but with the axial slide 7. Similar considerations apply to the considerations set out above for machining the workpiece. In particular, it can be avoided in this way that a direction reversal takes place along the X direction when modifications are generated on the grinding worm flank.
    The present invention is also advantageous when the dressing takes place with a gear-shaped dressing wheel clamped on the workpiece spindle.
    Other uses
    The advantages of the present invention have been explained above using the example of the production of broad-crowned modified spur gears. However, the invention is not limited to this application, but can also be used advantageously in the manufacture of other tooth systems or gearwheels. In particular, the invention also has advantages in the production of gearings modified in other ways, e.g., conically modified gearings, since disruptive frictional effects can also be avoided there with the invention.
    Second embodiment
    In FIG. 7, a generating grinding machine according to a second embodiment is shown schematically. This differs from the first embodiment in that the A-axis does not run perpendicular to the Z-direction and parallel to the X-direction, but perpendicular to the Z'-direction and accordingly at an angle ψ to the X-direction. As a result, the Y-axis and the tool axis B are no longer perpendicular to the X-direction as soon as the pivoting angle about the A-axis deviates from the position shown in FIG. 7. Nevertheless, the advantages mentioned above can also be achieved with this arrangement. This embodiment is particularly suitable for small angles of inclination between 0.1 ° and 3 °.
    Overall, in this embodiment, the following applies to the arrangement of the directions X, Y, Z, Z ', A, B and C1: A lies in the X-C1 plane lies in the X-C1 plane
    Because of the inclined A-axis, compared to the first embodiment, further coordinate transformations are necessary in order to convert from a coordinate system defined by the machine axes X, Y, Z ', A, B, C1 into an orthogonal coordinate system or into a conventional coordinate system of the machine control and vice versa. However, the corresponding transformations can easily be derived from simple trigonometric considerations.
    Third embodiment
    In FIG. 8, a generating grinding machine according to a third embodiment is shown schematically. In this embodiment, the entire tool carrier 5 including the axial slide 7, shift slide and grinding head 9 is conventionally constructed. In particular, the axial guidance direction Z ′ here runs perpendicular to the infeed direction X. Instead, the workpiece carrier (rotating tower) 15 is inclined here with respect to the vertical. As a result, in particular the workpiece axis C1 and thus also the axial feed direction Z, which by definition runs parallel to the workpiece axis C1, no longer runs perpendicular to the X direction.
    For this embodiment, too, further coordinate transformations are necessary compared to the first embodiment in order to convert from a coordinate system defined by the machine axes X, Y, Z ', A, B, C1 into an orthogonal coordinate system or into a conventional coordinate system Machine control and vice versa. The corresponding transformations can in turn be derived without any problems through simple trigonometric considerations.
    Fourth embodiment
    In FIG. 9, a generating grinding machine according to a fourth embodiment is shown schematically. As in the first and second embodiment, the turret with the axes C1 and C3 stands vertically in space, and the axial slide 7 is guided with respect to the tool carrier 5 along an axial guide direction Z 'which is at an angle of inclination ψ with respect to the workpiece axis C1 running vertically in space Vertical inclined. In contrast to the first and second embodiment, however, the entire tool carrier 5 including the axial slide 7, shift slide and grinding head 9 is not guided exactly horizontally on the machine bed 4, but along a direction that is inclined by the angle of inclination ψ to the horizontal. As in the embodiments discussed above, this guidance direction is again referred to as the X direction. The X direction is therefore not perpendicular to the Z direction here, but perpendicular to the Z 'direction. As in the first embodiment, the A-axis runs horizontally in space and thus perpendicular to the Z-direction. Because of the inclined X-guide, however, the A-axis does not run parallel to the X-direction.
    Overall, in this embodiment, the following applies to the arrangement of the directions X, Y, Z, Z ', A, B and C1: A lies in the X-C1 plane Z' lies in the X-C1 plane
    For this embodiment, too, further coordinate transformations are necessary compared to the first embodiment in order to convert from a coordinate system that is defined by the machine axes X, Y, Z ', A, B, C1, into an orthogonal coordinate system or into a conventional coordinate system Machine control and vice versa. The corresponding transformations can in turn be derived without any problems through simple trigonometric considerations.
    Modifications
    In the examples shown above, the angle of inclination ψ is positive, i.e. the Z 'axis is inclined towards the positive X direction or away from the workpiece axis C1. However, this angle can also be negative. The transformations mentioned retain their validity in this situation as well. A negative angle of inclination ψ can be particularly advantageous if the last finishing stroke takes place along the negative Z direction (ie from top to bottom in FIG. 2), since the tool carrier 5 then moves along the negative X direction to generate the compensation movement is, ie towards the workpiece. This is advantageous because in this way the radial machining forces counteract the compensation movement, which leads to defined force relationships in the components that are involved in generating the X movement.
    The present invention is not limited to a specific machining method. The advantages of the invention were explained above on the basis of continuous generating grinding. However, the invention also shows its advantages in other methods for producing toothings, including methods with a geometrically undefined cutting edge and methods with a geometrically defined cutting edge. Examples include indexing hobbing, discontinuous or continuous profile grinding, gear honing, hobbing or hob skiving. The invention can be used to manufacture both externally toothed workpieces and internally toothed workpieces. The invention is used particularly advantageously in the fine machining of pre-toothed workpieces, in particular in hard fine machining.
    The present invention is not limited to a specific axis sequence. Depending on the type of machine, it can also be advantageous, for example, to arrange the axial slide directly on the machine bed and to arrange the workpiece spindle on a radial slide in order to achieve the radial infeed by moving the workpiece spindle.
    The present invention is also not restricted to the fact that the radial infeed direction X runs perpendicular to the workpiece axis C1. In the third and fourth embodiment, the radial infeed direction X runs at an angle not equal to 90 ° to the workpiece axis C1. However, it is also advantageous in this situation if the axial guidance direction Z ′ runs in a common plane with the radial infeed direction X and the workpiece axis C1.
    Instead of two workpiece spindles, there can also be three or more workpiece spindles or only a single workpiece spindle. The at least one workpiece spindle does not need to be arranged on a movable workpiece carrier, but can be arranged directly on the machine bed. In other embodiments, the at least one workpiece spindle is arranged on a movable workpiece carrier which realizes the radial infeed movement along the X direction. The A-axis can also be implemented on the workpiece side instead of the tool side.
    The dressing device 13 can also be attached to the machine bed instead of a movable workpiece carrier. The tool carrier 5 can in this case be pivotable with respect to the machine bed in order to move the machining tool to the dressing tool, as is known per se, e.g. from US5857894B.
    It can be seen from the above that a very large number of relative arrangements of the axes involved is possible.
    The present invention is also not limited to specific types of drive for the various linear guides. It can be driven in any manner known in the art, such as ball screws or linear motors.
    权利要求:
    Claims (18)
    [1]
    1. Machine tool (1) for machining gears, having:a workpiece spindle (16) for driving a workpiece (18) to rotate about a workpiece axis (C1);a tool spindle (11) to drive a tool (12) to rotate about a tool axis (B);a feed slide (5) with which a radial axial distance between the tool axis (B) and the workpiece axis (C1) can be changed along a radial feed direction (X), and the radial feed direction (X) at an angle of 60 ° to 120 ° to The workpiece axis (C1), in particular perpendicular to the workpiece axis (C1); andan axial slide (7) with which a relative feed position between the tool spindle (11) and the workpiece spindle (16) can be changed along the workpiece axis (C1),characterized in that the axial slide (7) is guided along an axial guide direction (Z ') which runs in a common plane with the workpiece axis (C1) and the radial infeed direction (X) and by an angle of inclination (ψ) with respect to the workpiece axis (C1) ) is inclined, the amount of the angle of inclination (ψ) assuming a value between 0.1 ° and 30 °, in particular between 0.5 ° and 30 °.
    [2]
    2. Machine tool (1) according to claim 1, comprising:a machine bed (4);wherein the feed slide (5) is guided on the machine bed (4) so as to be displaceable along the radial feed direction (X) and forms a tool carrier;wherein the axial slide (7) is guided on the feed slide (5) along the axial guidance direction (Z ').
    [3]
    3. Machine tool (1) according to claim 1 or 2, wherein the tool spindle (11) is pivotable about a pivot axis (A) relative to the axial slide (7), and wherein the pivot axis (A) is in a common plane with the workpiece axis (C1) and the radial infeed direction (X) runs at an angle to the radial infeed direction (X) which, in terms of amount, assumes a value between 0 ° and 30 °, in particular parallel to the radial infeed direction (X).
    [4]
    4. Machine tool (1) according to claim 3, wherein the tool spindle (11) is displaceable relative to the axial slide (7) along a shift direction (Y) which runs parallel to the tool axis (B), the shift direction (Y) being perpendicular to the pivot axis (A) runs.
    [5]
    5. Machine tool (1) according to one of the preceding claims, having a control device (2, 3) which is designed to control the machine tool (1) in such a way that it has simultaneous movements between the tool spindle (11) and the workpiece spindle (16 ) executes along the inclined axial guide direction (Z ') and the radial feed direction (X).
    [6]
    6. Machine tool according to claim 5, wherein the control device (2, 3) is designed to carry out the following method:Execution of simultaneous movements between the tool spindle (11) and the workpiece spindle (16) along the inclined axial guide direction (Z ') and the radial feed direction (X), while a tool (12) clamped on the tool spindle (11) is engaged in machining the workpiece (18) clamped on the workpiece spindle is located,wherein the movement along the inclined axial guide direction (Z ') takes place at an axial guide speed and the movement along the radial feed direction (X) takes place at a radial feed speed,wherein the amount of the radial infeed speed does not fall below a predetermined threshold value during the machining of each individual tooth flank.
    [7]
    7. Machine tool (1) according to claim 6, wherein the control device (2, 3) is designed to control the radial infeed speed and the axial guide speed in such a way that the radial infeed speed and the axial guide speed are in a relationship that is different during machining the tooth flank changes.
    [8]
    8. Machine tool (1) according to claim 6 or 7, wherein the control device (2, 3) is designed to control the radial feed speed and the axial guide speed such that the radial feed speed does not change its sign during the machining of a tooth flank, while a resulting movement between the tool spindle (11) and the workpiece spindle (16) along the radial feed direction (X) has a speed (vX) which changes its sign during the machining of the tooth flank.
    [9]
    9. Machine tool (1) according to one of claims 5 to 8, having a dressing device (13) with a dressing tool (14), wherein the control device (2, 3) is designed to connect the tool (12) with the dressing tool (14) to dress while generating movements along the inclined axial guide direction (Z ') and, for this purpose, preferably to bring the tool spindle (11) into a dressing position in which the tool axis (B) runs in or parallel to a plane that is separated from the axial guide direction (Z') and the radial infeed direction (X) is spanned.
    [10]
    10. Machine tool (1) according to one of the preceding claims, wherein the machine tool is designed for one of the following methods: continuous generating grinding, partial generating grinding, discontinuous or continuous profile grinding, gear honing, hobbing or generating skiving.
    [11]
    11. A method for machining tooth flanks of a workpiece (18) with a machine tool (1) according to one of the preceding claims, comprising:Execution of simultaneous movements between the tool spindle (11) and the workpiece spindle (16) along the inclined axial guide direction (Z ') and the radial feed direction (X), while a tool (12) clamped on the tool spindle (11) is engaged in machining the workpiece (18) clamped on the workpiece spindle, the movement along the inclined axial guide direction (Z ') taking place at an axial guide speed and the movement along the radial feed direction (X) taking place at a radial feed speed.
    [12]
    12. The method according to claim 11, wherein the amount of the radial infeed speed does not fall below a predetermined threshold value during the machining of each individual tooth flank.
    [13]
    13. The method according to claim 11 or 12, wherein the radial infeed speed and the axial guide speed are in a ratio to one another which changes during the machining of a tooth flank.
    [14]
    14. The method according to claim 13, wherein the radial infeed speed and the axial guide speed are in a temporally variable relationship such that the radial infeed speed does not change its sign during the machining of a tooth flank, while a resulting movement between the tool spindle (11) and the workpiece spindle ( 16) has a speed (vX) along the radial infeed direction (X) which changes its sign during the machining of the tooth flanks.
    [15]
    15. The method according to any one of claims 11 to 14, wherein the method is one of the following methods: continuous generating grinding, partial generating grinding, discontinuous or continuous profile grinding, gear honing, hobbing or skiving.
    [16]
    16. A method for dressing a tool (12) for machining gears with a machine according to claim 9 or 10, comprising:Generating relative movements between the tool (12) and a dressing device (13) with a dressing tool (14) along the inclined axial guidance direction (Z '), while the tool (12) is in engagement with the dressing tool (14) in order to move the tool ( 12), whereby the tool spindle (11) is preferably brought into a dressing position before the dressing, in which the tool axis (B) runs in or parallel to a plane that is defined by the axial guidance direction (Z ') and the radial infeed direction (X) is stretched.
    [17]
    17. Computer program product, comprising a computer program with instructions which cause a control device (2, 3) of a machine tool (1) according to one of claims 5 to 9 to carry out a method according to one of claims 11 to 15.
    [18]
    18. Computer program product, comprising a computer program with instructions which cause a control device (2, 3) of a machine tool (1) according to claim 9 to carry out a method according to claim 16.
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    同族专利:
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    WO2021052787A1|2021-03-25|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    CH452322A|1965-02-04|1968-05-31|Reishauer Ag|Gear grinding machine|
    DE19625370C1|1996-06-25|1997-04-30|Reishauer Ag|Grinding machine for continuous roller grinding of spur wheel gears|
    DE19857592A1|1998-12-14|2000-06-15|Reishauer Ag|Machine for processing pre-toothed workpieces|
    DE102012016515B4|2012-08-20|2016-02-25|Liebherr-Verzahntechnik Gmbh|Gear shaping machine and associated method for the production of gears and profiles|
    EP3034221A1|2014-12-17|2016-06-22|Klingelnberg AG|Grinding machine with a grinding tool for roller grinding two workpieces|
    CH713798A1|2017-05-19|2018-11-30|Reishauer Ag|Machine for fine machining of toothed workpieces and method for measuring parameters of a finishing tool.|
    DE102018001103A1|2018-02-09|2019-08-14|Rheinisch-Westfälische Technische Hochschule Aachen|Device for toothing workpieces|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    CH11692019|2019-09-16|
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