• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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  • 优先权
    • 专利摘要:
    Elastic device with variable stiffness. actuator with variable stiffness and coupling with variable stiffness. Elastic device (10) comprising a first group of spiral springs (20a), attached to a shaft (21) and configured to selectively engage and disengage a first housing (22a); and a second group of coiled springs (20b), attached to the shaft (21) and configured to selectively engage and disengage a second housing (22b); in which there is provided at least one coupling means (24a, 24b) configured to selectively couple and uncouple at least one of the springs (20a) of the first group to the first housing (22a) or to selectively couple or uncouple at least one from the springs (20b) of the second group to the second casing (22b). (Machine-translation by Google Translate, not legally binding)
    公开号:ES2797550A1
    申请号:ES202030136
    申请日:2020-02-18
    公开日:2020-12-02
    发明作者:Guijosa Juan Manuel Munoz；Cabello Enrique Navarro；Tanarro Enrique Chacon；Lantada Andres Diaz
    申请人:Universidad Politecnica de Madrid；
    IPC主号:
    专利说明:

    [0004] Object of the invention
    [0006] The present invention belongs, among others, to the technical field of mechanical connections and is useful in many different sectors, such as, for example and without limitation, robotics, exoskeletons, vehicle suspensions, rehabilitation machines, bodybuilding machines, as well as structural systems.
    [0008] More particularly, the present invention has for its object an elastic device with variable stiffness. Said elastic device can be adjusted at will so that - when subjected to the action of a torque - the angular deflection generated in said device as a consequence of the action of said torque, is of greater or lesser magnitude.
    [0010] Likewise, the invention also relates to an actuator with variable stiffness comprising at least one of the elastic devices with variable stiffness mentioned above.
    [0012] Finally, the invention also relates to a coupling with variable stiffness comprising at least one of the elastic devices with variable stiffness mentioned above.
    [0014] Technical problem to solve and background of the invention
    [0016] In mechanical and structural terms, the stiffness of an element is the relationship between the force applied to said element and the deflection that said element experiences due to the action of said force.
    [0018] Thus, for example, torsional stiffness KT is the relationship between the torque dM applied to an element and the angular deflection d0 obtained in it:
    [0019] dM
    [0020] kt He
    [0022] The stiffness of an element is also related to its ability to transmit mechanical stresses, limiting its transmission to increases in force or torque as long as a greater deflection is not achieved in the element.
    [0024] Many engineering systems can see their characteristics improved if they have elements with adjustable stiffness.
    [0026] Thus, for example, the stiffnesses of the elements that constitute a structural system influence the natural frequencies of vibration or critical rotational speeds of said system. The structural design has, among other objectives, to determine the stiffness of the different elements that make up a structural system so that their natural frequencies or critical rotational speeds are far from the frequencies at which the stresses act on the system. The incorporation of elements of variable stiffness to structural systems would therefore be beneficial, since it would make it possible to increase the versatility of said structural systems since it is possible to vary their stiffness, depending on the frequencies at which the stresses act.
    [0028] In the same way, the use of joints with adjustable stiffness in robots would make said robot, as in the case of humans, able to improve positioning and gripping operations, reducing the effect that disturbances in the movements have on its structure. external requests.
    [0030] On the other hand, an adjustable stiffness joint in a robot that works in collaborative environments, capable of reducing its stiffness before one of the connecting elements hits a worker, would reduce the severity of the impact and therefore its consequences. Under normal operating conditions, the joint will have a higher stiffness, so that the effective transmission of forces and mechanical torques between the elements it connects is possible, which would allow the robot to perform its work properly.
    [0032] Another application that benefits from adjustable rigidity connections is robotic exoskeletons. Different biomechanical studies on human gait have shown that the hip, knee and ankle joints allow a different turn when facing the same pair depending on the position of the leg, calf and foot. This stiffness, which varies depending on the position of the joint, also makes it possible to regulate the energy stored in the muscles responsible for walking, so that the excess energy in some phases is recovered in others. The same goes for the shoulder, elbow and wrist or neck joints. The execution of the gait or of other movements or sequences of body movements by means of exoskeletons would be, consequently, more realistic, ergonomic and efficient if connections of variable stiffness are used between the different elements of the exoskeleton.
    [0034] Due to the aforementioned non-linearity of the joints, in training, gym or rehabilitation machines it is also necessary to adjust the rigidity of the system on which the subject to be trained must make an effort, so the incorporation of elements of rigidity variable, it would be beneficial.
    [0036] The possibility of varying the stiffness at will is also useful in many different machines, for example in machines provided with several transmission shafts connected to each other by means of couplings. In nominal working conditions, a high rigidity is necessary in the coupling, so that efficient transmission of torque between the connecting shafts is possible, simultaneously absorbing radial and angular misalignments between them. However, in the event of a sudden rise in the resistive torque, a substantial reduction in stiffness is beneficial, so that the connected elements are protected from mechanical overloads, thanks to a greater angular deflection in the coupling. This stress limitation can also be used in, for example, torque wrenches, so that the tightening torque obtainable with the wrench can be adjusted.
    [0038] Vehicles, machines and structures can also benefit from a suspension with adjustable stiffness. For example, in automobile and railway vehicles a suspension with high stiffness at high speeds is necessary so that it is possible to meet the requirements of dynamic stability. However, at low speeds, -for example, in sections with curves with a small radius of curvature, or with bumps- it is important that the stiffness of the suspension is lower, so that the transmission of efforts and accelerations to the driver or passengers can be limited. , as well as the suspended structure. Similar characteristics are required in automobile and rail vehicle torsion bars. In the same way, regulating the rigidity of the suspension of a machine can significantly reduce the transmission of vibrations towards its support if the rigidity of said Suspension is modified by changes in the frequency of the forces generated in the machine. Similarly, it is possible to isolate a structure from excitations from its support by modifying the stiffness of the suspension that joins the structure to the support, so that the natural frequencies of the structure are far from the frequencies of the excitation through the support. .
    [0040] Different methods are currently known to obtain a variable stiffness. For example, patent application W02014 / 001585 presents a system based on the preload of a rectilinear spring. However, the stiffness of the connection is very high up to the value of the spring preload. If the force exerted exceeds this value, the stiffness of the connection drops to that of the spring.
    [0042] Applications US2016082603 and TW201350095 present a connection of variable torsional stiffness, the variable stiffness being achieved by varying the free length of a beam on the center of which a torque is applied.
    [0044] Application US2015123417 obtains a joint with variable stiffness by modifying the shape of a beam by means of buckling it. Application US9366323 obtains a variable stiffness by modifying the useful length of an elastic element. Applications W02013025510 and KR20160033340 obtain a variable torsional stiffness connection by modifying the lever arm on which springs are actuated. The application EP1731336A1 presents an element with variable torsional stiffness through the variation of the flexural inertia of a beam, by modifying its axes of inertia with respect to the torsion plane. Application W02014033603A1 presents an adjustable stiffness system by preloading two non-linear elastic systems, in turn composed of springs with linear behavior.
    [0046] Some of the already known variable stiffness devices mentioned above achieve torsional stiffness by using rectilinear elastic elements. However, in such devices it is necessary to employ means for converting a linear movement into a rotational movement. Said means involve an increase in weight, size and cost.
    [0048] Other of the aforementioned variable stiffness devices achieve variable stiffness using elastic elements with constant stiffness, which also implies the need for means to modify the apparent stiffness of said constant stiffness springs, such as cables, pulleys, tensioners, cams, levers. variable arm, etc., or a combination of these. This also means additional weight, size and cost. The weight gain associated with the use of these peripheral systems may also imply a worsening of the dynamic response of the system and reaction time. The increase in size is especially problematic in systems such as robots, exoskeletons or cars. On the other hand, the increase in the number of components of the system reduces its reliability and raises the cost of maintenance.
    [0050] Description of the invention
    [0052] The present invention seeks to remedy or reduce the problems and disadvantages of the prior art, mentioned above.
    [0054] To this end, a first object of the present invention refers to an elastic device with variable stiffness, comprising:
    [0055] - A first group of torsion springs formed by at least one first spiral-shaped torsion spring, which defines a plurality of turns, said first spring being joined at one of its ends to a rotation shaft, its opposite end being configured to selectively engage and disengage a first housing;
    [0056] - A second group of torsion springs formed by at least one second spiral-shaped torsion spring, which defines a plurality of turns, said second spring being joined at one of its ends to the rotation shaft, its opposite end being configured to engage and selectively decoupled to a second housing;
    [0058] characterized in that it is provided with:
    [0059] - at least one means for fixing the relative position of one of the shells with respect to the other shell;
    [0060] - at least one coupling means configured to selectively couple and uncouple at least one of the torsion springs of the first group to the first casing, and / or configured to selectively couple and uncouple at least one of the springs of the second group to the second casing, such that the springs attached to the housings contribute to the stiffness of the elastic device and the uncoupled springs do not contribute to the stiffness of the elastic device.
    [0061] As will be explained in detail later, in the description of the examples of possible embodiments of the present invention, the coupling means (or alternatively the coupling means) between springs and housings with which the elastic device according to the invention is provided, allow vary at will the torsional stiffness of said device, that is, the relationship between the torque exerted and the rotation obtained between the shaft and the housings. Thus, if at a certain moment it is desired to increase the torsional stiffness of the elastic device, it is enough to couple at least one additional spring from the first group of springs to the first housing and / or to couple at least one additional spring from the second group to the second housing. springs, taking advantage of one or more coupling means.
    [0063] In one embodiment of the invention, the springs of the first group of torsion springs and the springs of the second group of torsion springs are mounted antagonistically to each other, that is, they are arranged so that the first group of springs runs in the direction contrary to the second group of springs (in other words, the turns of the springs of the first group run in the opposite direction to the turns of the springs of the second group).
    [0065] In said embodiment of the invention, the elastic device of variable stiffness is provided with at least one coupling means between springs and housings in the form of a projection that protrudes from an inner surface of the first housing being, in addition, at least one of the torsion springs of the first group of torsion springs provided with a recess delimited by two staggered edges, said staggered edges being configured to engage by contact with the projection upon reaching a predetermined angle of rotation of the first casing relative to the rotation shaft and for disengaging from said projection, upon loss of said contact when the first casing rotates again relative to the rotation shaft.
    [0067] The stiffness of the elastic device is thus determined by fixing the relative position of one of the casings with respect to the other casing, rotating one in the opposite direction to the other by the required angle, and then preventing relative movement between them. . Determining the widths of the recesses of each of the springs of each group allows a greater or lesser number of springs to be coupled to each casing at different relative positions of one casing relative to the other. This configuration also makes it possible to achieve zero stiffness if the relative position of one casing with respect to the other is such that none of the springs is coupled to its corresponding casing.
    [0068] In another embodiment of the invention, the elastic device of variable stiffness is provided with at least one coupling means between springs and housings in the form of a projection that protrudes from an inner surface of the second housing being, in addition, at least one of the springs of torsion of the second group provided with a recess delimited by two stepped edges, said stepped edges being configured to engage by contact with the projection upon reaching a predetermined angle of rotation of the second casing relative to the rotation shaft and to disengage from said projection as the second housing rotates again relative to the rotation shaft.
    [0070] In a second embodiment of the present invention, the two housings are rigidly and permanently attached and the outer perimeter of at least one spring of the first group and / or of at least one spring of the second group of torsion springs is provided with a toothing, at least one tooth-shaped coupling means being further provided, configured to selectively extend and retract by means of an actuator - for example, electromagnetic-, such that when the tooth-shaped coupling means extends, it meshes with the teeth of the outer perimeter of the spring, coupling said spring to the corresponding casing and when the tooth-shaped coupling means is retracted, it disengages from the toothing of the spring disengaging said spring from the corresponding casing.
    [0072] The springs of the first and / or of the second group can be made from a composite material, or by means of an additive manufacturing process, which also allows that, if desired, said springs have a variable stiffness along their length. length.
    [0074] Likewise, the springs of the first group and the springs of the second group are preferably provided with a keyway intended to house a key provided in the rotation shaft.
    [0076] The elastic device with variable stiffness, according to any of the embodiments described above, can optionally be made by an additive manufacturing process, such as three-dimensional printing.
    [0078] A second object of the present invention refers to an actuator with variable stiffness useful, without limitation, in robots, exoskeletons, weight training machines, rehabilitation machines or suspensions of vehicles and machines.
    [0079] Said actuator with variable stiffness comprises at least one elastic device with variable stiffness, according to any of the embodiments described above, and is configured to connect and allow relative movement, overcoming mechanical stresses, between two elements of a kinematic chain, one of said being elements of the kinematic chain connected to the shaft and the other element connected to at least one of the housings.
    [0081] A first embodiment of the actuator is based on the use of the first embodiment of the elastic device, in which the means for fixing the relative position between the shells (to modify the rigidity of the elastic element) and between them and the first member of the kinematic chain (to achieve the relative movement between both members of the kinematic chain) are, for example, two electric motors. In a first configuration of this first embodiment, the stator of each of the two electric motors is connected to the first element of the kinematic chain, while the rotor of each of the two motors transmits the rotational movement to the two casings at through the peripheral teeth of these. In a second configuration of this first embodiment, one of the electric motors is connected by its stator to one of the casings, its rotor transmitting the rotational movement to the other casing through its peripheral teeth; and the other motor is connected by its stator to the first member of the kinematic chain and transmits the rotational movement through its rotor to one of the casings through its peripheral teeth.
    [0083] A second embodiment of the actuator is based on the use of the second embodiment of the elastic device, in which the means for modifying the position between the first and second housings, rigidly and permanently attached, and the first member of the kinematic chain are, for example, an electric motor whose stator is attached to the first member of the kinematic chain, and whose rotor transmits the rotational movement to the housings through their peripheral teeth.
    [0085] A third aspect of the present invention refers to a coupling with variable stiffness useful, without limitation, in rehabilitation machines, bodybuilding machines, vehicle and machine suspension systems, or couplings between transmission shafts. Said coupling comprises at least one elastic device with variable stiffness, according to any of the embodiments described above, and is configured to connect and allow relative movement, overcoming mechanical stresses, between two elements of a kinematic chain, one of said elements being of the kinematic chain connected to the shaft and the other element connected to at least one of the housings.
    [0086] A first embodiment of the variable stiffness coupling is based on the use of the first embodiment of the elastic device, in which the means for fixing the relative position between the first and second shells are, for example, an electric motor, the stator of which is attached to one of the casings, its rotor transmitting the rotational movement to the other casing through its peripheral teeth. It also has means for fixing the position of the casings with respect to the first member of the kinematic chain, such as, for example, reversible and lockable freewheels, thus allowing rotation in a specific and selectable direction, but preventing it in the opposite direction, or preventing rotation in any direction.
    [0088] A second embodiment of the variable stiffness coupling is based on the use of the first embodiment of the elastic device, in which the means for fixing the relative position between the first and second shells are manual. For example, a bolt can be used which, coupled between the peripheral teeth of each housing, prevents their relative movement. It also has means for fixing the position of the casings with respect to the first member of the kinematic chain, such as, for example, reversible and lockable freewheels, thus allowing rotation in a specific and selectable direction, but preventing it in the opposite direction, or preventing rotation in any direction.
    [0090] A third embodiment of the variable stiffness coupling is based on the use of the second embodiment of the elastic device, in which the means for fixing the relative position between the first and second casings and the first member of the kinematic chain are, for example, Reversible and lockable freewheels, thus allowing rotation in a specific and selectable direction, but preventing it in the opposite direction, or preventing rotation in any direction.
    [0092] A fourth aspect of the present invention refers to the use of at least one variable stiffness actuator, according to any of the previously described embodiments, in a suspension of a vehicle or a machine, a torsion bar, an exoskeleton, a robot, a torque wrench, a weight training machine, or a rehab machine.
    [0094] Finally, a fifth aspect of the present invention refers to the use of at least one variable stiffness coupling, according to any of the previously described embodiments, in a suspension of a vehicle or a machine, a torsion bar, an exoskeleton, a robot, a torque wrench, a weight training machine or a rehabilitation machine.
    [0095] Description of the figures
    [0097] To complement the present description and in order to help a better understanding of the technical characteristics of the invention, according to preferred examples of practical embodiments thereof, a set of drawings is attached as an integral part of said description where, For illustrative and non-limiting purposes, the following has been represented:
    [0099] Fig. 1A.- Is a perspective view of a first embodiment of an elastic device with variable stiffness according to the present invention, duly assembled;
    [0101] Fig. 1B.- Is a perspective view, partially exploded, of an elastic device of variable stiffness similar to that of Fig. 1A;
    [0103] Fig. 1C is an exploded view of the elastic device shown in 1B;
    [0105] Fig. 2A.- Is a perspective view of a second embodiment of an elastic device with variable stiffness according to the present invention, properly assembled;
    [0107] Fig. 2B.- Is an exploded perspective view of the elastic device of variable stiffness of Fig. 2A;
    [0109] Fig. 3A.- Is a perspective view of a first embodiment of a variable stiffness actuator according to the present invention;
    [0111] Fig. 3B.- Is a perspective view of a second embodiment of a variable stiffness actuator according to the present invention;
    [0113] Fig. 3C.- Is a perspective view of a first embodiment of a variable stiffness coupling according to the present invention;
    [0115] Fig. 3D.- Is a perspective view of a third embodiment of a variable stiffness coupling according to the present invention;
    [0116] Numerical references of the figures
    [0118] (10) Elastic device of the invention;
    [0119] (20a) Springs of the first group of coil springs;
    [0120] (20b) Springs of the second group of coil springs;
    [0121] (21) Rotation tree;
    [0122] (22a) First shell;
    [0123] (22b) Second housing;
    [0124] (22a ') Cover of the first casing;
    [0125] (22b ') Cover of the second housing;
    [0126] (23) Key;
    [0127] (24a) Projection-shaped coupling means;
    [0128] (24b) Tooth-shaped coupling means;
    [0129] (25) Keyway provided in the springs (of the first and second groups);
    [0130] (26) Lowering the springs (of the first and second groups);
    [0131] (27) Actuator;
    [0132] (28) Toothing of the springs (of the first and second groups);
    [0133] (29) Washer;
    [0134] (30) Staggered edge of the recesses;
    [0135] (31) Means for fixing the relative position of one casing with respect to the other;
    [0136] (71) Fastening element;
    [0137] (73) Swing motor;
    [0138] (74) Fixed support;
    [0139] (100) Variable stiffness actuator;
    [0140] (200) Variable stiffness coupling; and
    [0141] (221) Toothed crowns of the housings.
    [0143] Description of an embodiment of the invention
    [0145] A detailed description of two preferred embodiments of the present invention is provided below, with the aid of the attached Figures 1A to 3D.
    [0147] Throughout the present description, as well as in the attached figures, elements with the same or similar functions will be designated with the same reference numbers.
    [0148] Figure 1A shows a first embodiment of an elastic device 10 with variable stiffness according to the present invention. Figures 1B and 1C show a second elastic device 10 very similar to the elastic device 10 of Figure 1A and that it only differs from it in that, in this second embodiment, the toothed rings 221 occupy the entire lateral surface of the housings 22a and 22b, and not just a part of it.
    [0150] As can be seen especially in Fig. 1C, in these particular embodiments of the invention the first group of torsion springs is formed by three different torsion springs 20a, with a spiral shape, while the second group of torsion springs is formed by three different torsion springs 20b, also spiral shaped.
    [0152] All springs 20a and all springs 20b are attached to the same rotary shaft 21.
    [0154] To facilitate the integral fixing of springs 20a and springs 20b to shaft 21, each of said springs 20a and springs 20b has a central hole through which it is inserted into shaft 21. Springs 20a and springs 20b are furthermore provided with a keyway 25 intended to house a key 23 provided in the shaft 21.
    [0156] The device 10 is also provided with a first housing 22a that surrounds the first group of torsion springs 20a and a second housing 22b that surrounds the second group of torsion springs 20b. Furthermore, the housings 22a and 22b are provided with a central hole that allows them to be positioned relative to the shaft 21.
    [0158] Also, as shown in Fig. 1A, means 31 are provided for fixing the relative position of one of the casings 22a with respect to the other casing 22b. In this embodiment of the invention the means 31 is a wedge or manual latch that is inserted between the teeth of the toothed rings 221 of the housings 22a and 22b.
    [0160] However, the present invention also expressly contemplates the possibility that said means 31 is part of an electric motor provided with a mechanical transmission, a hydraulic system, etc. (as shown for example, in Fig. 3A).
    [0162] The inner surface of the housing 22a and the inner surface of the housing 22b are provided with a projection-shaped coupling means 24a (although in Figures 1B and 1C only the coupling means 24a corresponding to the housing 22a) is visible. Said coupling means 24a are configured to engage with stepped edges 30 that delimit a recess 26 provided in each of the springs 20a and in each of the springs 20b.
    [0164] In this way, by rotating the casing 22a and depending on the direction of rotation, the width of each projection and the magnitude of said rotation, it is possible to couple to or uncouple from the casing 22a each of the springs 20a. Similarly, by rotating the casing 22b and depending on the direction of rotation, the width of each projection and the magnitude of said rotation, it is possible to couple each of the springs 20b from said casing 22b.
    [0166] This specific configuration of the elastic device 10 of the invention, described in the previous paragraphs, allows to selectively vary its torsional stiffness, including zero stiffness, since any spring 20a, 20b that is coupled to its respective housing 22a, 22b thanks to the position The relative relationship between the casing and the inner shaft will contribute to increasing the rigidity of the device, while the springs 20a, 20b that are uncoupled from their respective casing 22a, 22b will not affect the rigidity, as they do not exert an appreciable resistance to torsion.
    [0168] A second embodiment of an elastic device 10 with variable stiffness according to the present invention is shown in Figures 2A and 2B.
    [0170] As can be seen in Fig. 2B, in this particular embodiment of the invention, the shells are rigidly attached. Furthermore, the first group of torsion springs is formed by a single torsion spring 20a, with a spiral shape, while the second group of torsion springs is formed by a single torsion spring 20b, also with a spiral shape. Spring 20a and spring 20b are attached to the same rotation shaft 21.
    [0172] As in the previous embodiment, described in relation to Figures 1A-1C, to facilitate the integral fixing of springs 20a and 20b to shaft 21, each of said springs 20a and 20b has a central hole through which it is inserted into the shaft 21, said springs 20a and 20b being also provided with a keyway 25 intended to house a key 23 provided in the shaft 21.
    [0173] On the other hand, the outer perimeter of the springs 20a and 20b is provided with a toothed edge 28. Also, two actuators 27 are provided on the housing 22a, two other actuators 27 being provided on the housing 22b. The number of actuators will depend on the torque to be transmitted and the resistance of the teeth 28 and the coupling means 24b. Each of said actuators 27 is configured to selectively extend or retract a tooth-shaped coupling means 24b, such that when one of said coupling means 24b is extended, said coupling means 24b engages with the toothed edge 28 of the corresponding spring 20a or 20b, coupling said spring to the corresponding housing 22a, 22b.
    [0175] Also, when one of the tooth-shaped coupling means 24b is retracted, said coupling means 24b disengages from the toothed edge 28 of the spring by disengaging said spring 20a or 20b from the corresponding housing 22a, 22b.
    [0177] In this particular embodiment of the invention, illustrated in Figures 2A and 2B, the elastic device 10 can adopt four different torsional stiffness values, namely:
    [0179] 1) essentially zero stiffness in the case where both spring 20a and spring 20b are uncoupled;
    [0181] 2) a stiffness due exclusively to spring 20a when it is coupled to housing 22a, as the actuators 24b provided in housing 22a have extended and spring 20b is uncoupled;
    [0183] 3) a stiffness due exclusively to spring 20b when it is coupled to housing 22b, as the actuators 24b provided in housing 22b have extended and spring 20a is disengaged; and
    [0185] 4) a maximum value of the stiffness, which appears when the spring 20a is coupled to the casing 22b and - simultaneously - the spring 20b is coupled to the casing 22b.
    [0187] In this particular embodiment of the invention each of the housings 22a, 22b is provided with a respective cover 22a 'and 22b' that includes a washer 29. The present invention is not limited, in any way, to the embodiments disclosed herein.
    [0189] In Figure 3A a first embodiment of a variable stiffness actuator 100 is shown, comprising an elastic device 10 of variable stiffness, similar to that shown in Fig. 1A.
    [0191] The elastic device 10 of variable stiffness is arranged between two clamping elements 71, perpendicular to a fixed horizontal support 74 and rigidly attached thereto.
    [0193] In this particular embodiment of the invention, the means 31 for fixing the relative position between the casings 22a, 22b (to modify the rigidity of the elastic element 10) and between them and the first member of the kinematic chain (to achieve the movement relative between both members of the kinematic chain) are the rotors of two electric motors 73. In a first configuration of this first embodiment, the stator of each of the two electric motors 73 is connected to the first element of the kinematic chain, while the rotor 31 of each of the two motors 73 transmits the rotational movement to the two housings 22a, 22b through the peripheral teeth 221 of the latter.
    [0195] The second element of the kinematic chain is in turn connected to shaft 21. For this, shaft 21 can optionally be provided, at at least one of its ends, with a coupling.
    [0197] In Figure 3B a second embodiment of a variable stiffness actuator 100 is shown which, in this particular embodiment of the invention, comprises an elastic device 10 of variable stiffness similar to that shown in Figures 2A and 2B. The actuator 100 connects with variable rigidity two elements of a kinematic chain (the first member joined to the horizontal support 74 and the second not shown in the figure), the second member of the kinematic chain being connected to the shaft 21 and the first member being of the kinematic chain connected to the stator of the electric motor 73. The rotor of the electric motor drives the peripheral teeth of the housings and therefore allows the determination of their relative position with respect to the member 1 of the kinematic chain. If the transmission between the rotor of the electric motor and the teeth is carried out by means of a self-retaining element (for example, certain types of augers), it is possible to fix the relative position of the casings with respect to the first member of the kinematic chain without necessity to supply power to the electric motor.
    [0199] The elastic device 10 of variable stiffness is provided with actuators 27. Each of said actuators 27 is configured to selectively extend or retract a tooth-shaped coupling means (not visible in Fig. 3B), such that when it is extends one of said teeth, it meshes with a toothed edge of a spring, coupling it to the corresponding housing 22a, 22b.
    [0200] Also and as in other embodiments, in this particular embodiment of the actuator 100 according to the invention shown in Figure 3B, the elastic device 10 of variable stiffness is arranged between two clamping elements 71, belonging to the first member of the kinematic chain.
    [0202] An embodiment of a variable stiffness coupling 200 is shown in Figure 3C, comprising an elastic device 10 of variable stiffness as shown in Figure 1A. Coupling 200 connects two elements of a kinematic chain with variable rigidity (not shown in the figures), one of said elements of the kinematic chain being connected to shaft 21 and the other element of the kinematic chain being connected to at least one of the housings 22a, 22b.
    [0204] In this particular embodiment of the coupling 200 according to the invention, the elastic device 10 of variable stiffness is arranged between two clamping elements 71, perpendicular to a horizontal fixed support 74 and rigidly connected thereto. Likewise, the element 31 for fixing the relative position of the housings 22a and 22b is a wedge 31 that is inserted between the teeth of the toothed rings 221 of the housings 22a and 22b.
    [0206] In this particular embodiment of the coupling 200 according to the invention shown, the elastic device 10 of variable stiffness is also arranged between two fastening elements 71 to the first member of the kinematic chain, which can be, for example, reversible and lockable free wheels, allowing in this way the rotation in a specific and selectable direction, but preventing it in the opposite, or preventing the rotation in any direction.
    [0208] An alternative embodiment of a variable stiffness coupling 200 is shown in Figure 3D which, in this particular embodiment of the invention, comprises an elastic device 10 of variable stiffness equal to that shown in Figures 2A and 2B. Coupling 200 connects with variable rigidity a first member attached to horizontal support 74 and a second member (not shown in the figure) of a kinematic chain, the second member of the kinematic chain being connected to shaft 21 and the first member of the kinematic chain connected to at least one of the housings 22a, 22b.
    [0210] The elastic stiffening device 10 is provided with actuators 27. Each of said actuators 27 is configured to selectively extend or retract a tooth-shaped coupling means (not visible in Fig. 3D), such that when it is extends one of said teeth, it meshes with a toothed edge of a spring, coupling it to the corresponding housing 22a, 22b.
    [0212] In this particular embodiment of the coupling 200 according to the invention shown, the elastic device 10 of variable stiffness is also arranged between two fastening elements 71 to the first member of the kinematic chain, which can be, for example, reversible and lockable free wheels, allowing in this way the rotation in a specific and selectable direction, but preventing it in the opposite, or preventing the rotation in any direction.
    [0214] Other possible embodiments of this invention will be apparent to the person skilled in the art in light of the present disclosure. Consequently, the scope of protection of the present invention is defined exclusively by the claims that follow.
    权利要求:
    Claims (12)
    [1]
    1. Elastic device (10) with variable stiffness, comprising:
    - a first group of torsion springs (20a) formed by at least one first torsion spring (20a), with a spiral shape, defining a plurality of turns, said first spring (20a) being joined at one of its ends to a rotation shaft (21), its opposite end being configured to selectively engage and disengage a first housing (22a);
    - a second group of torsion springs (20b) formed by at least one second torsion spring (20b), with a spiral shape, defining a plurality of turns, said second spring (20b) being joined at one of its ends to the shaft rotation (21) with its opposite end configured to selectively engage and disengage a second housing (22b);
    characterized in that it is provided with:
    - at least one means (31) for fixing the relative position of one of the shells (22a; 22b) with respect to the other shell (22b; 22a);
    - at least one coupling means (24a, 24b) configured to selectively couple and uncouple at least one of the springs (20a) of the first group to the first housing (22a) or configured to selectively couple and uncouple at least one of the springs (20b) of the second group to the second casing (22b), in such a way that the springs (20a, 20b) coupled to the casings (22a, 22b) contribute to the rigidity of the elastic device (10) and the springs (20a , 20b) uncoupled do not contribute to the rigidity of the device (10).
    [2]
    Elastic device (10) according to claim 1, in which the first group of springs (20a) runs in the opposite direction to the second group of springs (20b).
    [3]
    Elastic device (10) according to any of the preceding claims, in which at least one coupling means (24a) is provided in the form of a projection projecting from an inner surface of the first housing (22a) being, in addition, at the minus one of the torsion springs (20a) of the first group provided with a recess (26) delimited by two staggered edges (30), said staggered edges (30) being configured to engage by contact with the projection (24a) upon reaching an angle rotation of the first casing (22a) relative to the rotation shaft (21) and to disengage from said projection (24a) upon loss of said contact, when the first casing (22a) further rotates relative to the rotation shaft (21).
    [4]
    Elastic device (10) according to any of the preceding claims, further provided with at least one coupling means (24a) in the form of a projection projecting from an inner surface of the second casing (22b) being, in addition, at least one of the torsion springs (20b) of the second group provided with a recess (26) delimited by two staggered edges (30), said staggered edges (30) being configured to engage by contact with the projection (24a) upon reaching an angle of predetermined rotation rotation of the second housing (22b) relative to the rotation shaft (21) and to disengage from said shoulder (24a) by further rotating the second housing (22b) relative to the rotation shaft (21).
    [5]
    Elastic device (10) according to claim 1, in which the two shells (22a, 22b) are rigidly and permanently joined and the outer perimeter of at least one spring (20a) of the first group and / or of at least one Spring (20b) of the second group is provided with an edge (28), at least one coupling means (24b) in the form of a tooth being further provided configured to selectively extend and retract by means of an actuator (27), such that when the tooth-shaped coupling means (24b) extends, meshes with the teeth (28) of the spring (20a, 20b), coupling said spring to the corresponding housing (22a, 22b) and when the actuator (24b) in The tooth retracts, the actuator (24b) disengages from the edge (28) of the spring disengaging said spring (20a, 20b) from the corresponding housing (22a, 22b).
    [6]
    Elastic device (10) according to any of the preceding claims, in which the springs (20a) of the first group and the springs (20b) of the second group are provided with a keyway (25) intended to house a provided key (23 ) on the rotation shaft (21).
    [7]
    7. Elastic device (10) with variable stiffness, according to any of claims 1 to 6, characterized in that it is made by means of an additive manufacturing process.
    [8]
    8. Elastic device (10) with variable stiffness, according to claim 7, characterized in that the additive manufacturing process is three-dimensional printing.
    [9]
    9. Variable stiffness actuator (100), characterized in that it comprises at least one elastic device (10) with variable stiffness, according to any of claims 1 to 8, said actuator being configured to connect and allow relative movement, overcoming mechanical stresses, between two elements of a kinematic chain, one of said elements of the kinematic chain being connected to the shaft (21) and the other element of the kinematic chain connected to, at least one of the housings (22a, 22b).
    [10]
    10. Variable stiffness coupling (200), characterized in that it comprises at least one elastic device (10) with variable stiffness, according to any of claims 1 to 8, said coupling (200) being configured to connect and allow relative movement, overcoming mechanical stresses, between two elements of a kinematic chain, one of said elements of the kinematic chain being connected to the shaft (21) and the other element of the kinematic chain connected to at least one of the housings (22a, 22b) .
    [11]
    11. Use of at least one variable stiffness actuator (100) according to claim 9, in a suspension of a vehicle or a machine, a torsion bar, an exoskeleton, a robot, a torque wrench, a weight training machine or a rehabilitation machine.
    [12]
    Use of at least one variable stiffness coupling (200) according to claim 10, in a suspension of a vehicle or a machine, a torsion bar, an exoskeleton, a robot, a torque wrench, a weight training machine or a rehabilitation machine.
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    同族专利:
    公开号 | 公开日
    ES2797550B2|2021-04-08|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    GB1189800A|1969-02-24|1970-04-29|John Robert Ramsey|Drum Beater Device.|
    DE102012112084A1|2012-12-11|2014-06-12|Dorma Gmbh & Co. Kg|Door fastener for operating door leaf of door, has spring unit that is formed from several spiral springs which are extended in respective planes around door shaft|
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