Speed reduction transmission device, joint module and robot system

Abstract

The invention provides a speed reduction transmission device, a joint module and a robot system.The speed reduction transmission device comprises a driving wheel shaft capable of rotating around the central axis of the driving wheel shaft; the transmission assembly comprises at least one friction wheel capable of rotating, and the at least one friction wheel is arranged in the circumferential direction of the driving wheel shaft and abuts against and makes friction contact with the outer circumferential face of the driving wheel shaft; the fixing part abuts against and is in frictional contact with the peripheral surface of the friction wheel, so that the friction wheel can be driven by the friction force of the driving wheel shaft to revolve around the central axis of the driving wheel shaft; the transmission assembly is in transmission connection with the output part to drive the output part to rotate, and the rotating speed of the output part is smaller than that of the driving wheel shaft. According to the speed reduction transmission device, rotation and revolution of the friction wheel are driven through friction force, a gear tooth meshing structure is omitted, generation of tooth gaps is avoided, theoretical back gaps can reach zero, and the problem of positioning precision attenuation caused by the back gaps is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of reducers, and in particular to a reduction transmission device, a joint module and a robot system. Background Art

[0002] In the field of robot joint drive, the reducer is the core component for achieving deceleration and torque increase. Its performance directly determines the robot's motion accuracy, load capacity and service life. Currently, the mainstream RV reducers, harmonic reducers and planetary reducers for industrial robotic arms and humanoid robots all face backlash, that is, return error. The backlash can only be reduced infinitely. At the same time, smaller and more stable backlash means that parts require higher processing precision, and higher processing precision means higher cost, which is extremely unfriendly to commercial implementation.

[0003] Due to the backlash in the joints, with the long-term use of the product, the wear between the parts will increase, which will increase the backlash and cause the product to deviate from the use position, resulting in inaccurate positioning accuracy and affecting the robot function. Of course, as the algorithm control becomes more and more advanced, backlash compensation can also be performed in the control field, which naturally requires more advanced chips and control programs, and naturally brings about an increase in cost. At the same time, there is no regularity in the deterioration of backlash. During the entire life cycle of the product, it is difficult to compensate in real time through the control algorithm, and ultimately the stability of the overall functional performance of the machine cannot be guaranteed.

[0004] In addition, due to the existence of backlash, impact will inevitably occur when the whole machine is reversed, which will aggravate the damage of the transmission components and reduce the fatigue life. At the same time, the reverse direction also brings great difficulties to the control. The control algorithm must take into account the influence of the reverse backlash on the motion accuracy.

[0005] Therefore, a novel reduction transmission device is needed badly. Summary of the Invention

[0006] In view of this, embodiments of the present invention are directed to providing a reduction transmission device, a joint module, and a robot system to solve the problem of backlash in gear transmission due to tooth clearance in the prior art.

[0007] In a first aspect, the present application proposes a reduction transmission device, comprising:

[0008] The driving wheel shaft is capable of rotating around its central axis;

[0009] a transmission assembly, the transmission assembly comprising at least one rotatable friction wheel, the at least one friction wheel being arranged along the circumference of the driving wheel shaft and being in abutment and frictional contact with the outer circumference of the driving wheel shaft;

[0010] a fixing member, the fixing member abutting and frictionally contacting the outer peripheral surface of the friction wheel, so that the friction wheel can revolve around the central axis of the driving wheel shaft under the drive of the friction force of the driving wheel shaft;

[0011] The output member is connected to the transmission assembly to drive the output member to rotate, wherein the rotation speed of the output member is lower than the rotation speed of the driving wheel shaft.

[0012] The reduction transmission device according to the present application further includes a first support bearing. A pin is provided on the output member, and the first support bearing and the friction wheel are sequentially sleeved on the outer side of the pin along a radial direction.

[0013] The reduction transmission device according to the present application further includes:

[0014] The pre-tightening assembly includes an elastic member and a pressure member. The elastic member is in a compressed state and connected to the pressure member. The pressure member can generate a force on the friction wheel or the fixing member so that the two are pressed against each other along the normal direction of the contact surface.

[0015] Optionally, a guide cavity is provided on the friction wheel, and the axis of the guide cavity has an angle ɑ with the axis of the friction wheel, 0°≤ɑ<90°. The pressure piece is provided in the guide cavity and can move along the axial direction of the guide cavity. The guide cavity has a first guide surface, and the first guide surface is inclined from the inside of the guide cavity to the outside of the guide cavity in a direction gradually away from the axis of the guide cavity. The pressure piece has a second guide surface, and the second guide surface is in contact with the first guide surface. The elastic piece abuts against the outward end surface of the pressure piece.

[0016] Optionally, a hollow groove is further provided on the friction wheel, the opening of the hollow groove is located on one end surface of the friction wheel, and the opening of the guide cavity is located on the other end surface of the friction wheel.

[0017] Optionally, the hollow groove is arranged in an annular shape and is located on a side of the guide cavity away from the driving wheel shaft in the radial direction of the friction wheel.

[0018] Optionally, first radial bearings are respectively provided on both sides of the friction wheel in the axial direction, and the first radial bearings on both sides are respectively in contact with both side end surfaces of the friction wheel.

[0019] Optionally, a first axial hole is provided on the output member, the driving wheel shaft is passed through the first axial hole, a first stop member is also provided in the first axial hole, a second stop member is provided on the driving wheel shaft, the second stop member is located on the side of the first stop member away from the friction wheel, and a second radial bearing is sandwiched between the second stop member and the first stop member.

[0020] Optionally, a second support bearing is further provided in the first shaft hole, and the second radial bearing includes an inner ring, an outer ring and a rolling element, the inner ring abuts against the second stop member, and the outer ring abuts against the first stop member, the inner ring includes a radial end portion and an axial support portion connected to the radial end portion and extending axially along the driving wheel shaft, the radial end portion abuts against one side of the second support bearing, and the axial support portion is clamped between the driving wheel shaft and the second support bearing.

[0021] Optionally, the reduction transmission device further includes:

[0022] A planetary carrier cover plate, the planetary carrier cover plate and the output member are respectively arranged on both sides of the friction wheel, the planetary carrier cover plate is provided with a second axial hole, the driving wheel shaft is passed through the second axial hole, a boss is provided on the output member, the boss and the friction wheel are spaced apart along the circumference of the driving wheel shaft, a connecting member is passed through the planetary carrier cover plate, and the connecting member is threadedly connected to the boss.

[0023] In a second aspect, the present application proposes a joint module comprising the above-mentioned reduction transmission device.

[0024] In a third aspect, the present application proposes a robot system, comprising a moving component and the above-mentioned reduction transmission device, wherein the output member of the reduction transmission device is in transmission connection with the moving component.

[0025] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0026] The reduction transmission device provided by the present application has a structure in which, when the driving wheel shaft rotates about its central axis, its outer peripheral surface and the outer peripheral surface of the friction wheel come into frictional contact, thereby generating tangential friction. The rotational power of the driving wheel shaft is transmitted to the friction wheel through the frictional force, driving the friction wheel to rotate about its own axis. At this time, the rotation direction of the friction wheel is opposite to that of the driving wheel shaft. The fixed member abuts and maintains frictional contact with the outer peripheral surface of the friction wheel. Because the fixed member remains stationary, when the friction wheel rotates, friction generates resistance at the contact point between its outer peripheral surface and the fixed member, exerting a tangential constraint on the friction wheel. As the friction wheel rotates, it is forced to orbit around the central axis of the driving wheel shaft due to the combined effects of the friction force of the driving wheel shaft and the resistance of the fixed member. Because the friction wheel is in transmission connection with the output member, the linear velocity of the friction wheel's orbit is less than the linear velocity of the driving wheel shaft's rotation, thereby achieving a reduction effect in which the output member's rotational speed is less than the driving wheel shaft's rotational speed.

[0027] The friction wheel is in friction contact with the driving wheel shaft and the fixed parts. The rotation and revolution of the friction wheel are both transmitted by friction force. There is no gear tooth meshing structure to avoid the generation of tooth gap. The theoretical backlash can reach zero, avoiding the problem of positioning accuracy degradation caused by backlash. There is no tooth gap and backlash during the transmission process. During switching, the friction force changes synchronously with the rotation direction of the driving wheel shaft, which has faster response, greatly reduces impact load, and extends the fatigue life of the transmission components. It can maintain stable friction force and reduction ratio without relying on complex algorithms to compensate for backlash in real time. In addition, there is no need to deal with the phase lag caused by meshing gap, which reduces dependence on high-computing power chips and simplifies control system design and cost.

[0028] In addition, since the transmission of power relies on the friction between the friction wheel and the driving wheel shaft, the allowable output torque needs to be less than the friction resistance torque generated by the friction between the friction wheels. If the torque at the load end is greater than the friction resistance torque, slippage will occur between the friction wheels, and there will be no power output, thus preventing the transmission components from bearing destructive loads due to overload. At the same time, the power transmission can be automatically restored. When the load torque falls below the friction resistance torque, the friction force can automatically restore the power transmission without the need for additional clutch or sensor intervention, which simplifies the structural design and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Shown is a front view of a reduction transmission device according to an embodiment of the present application.

[0030] Figure 2 Shown Figure 1 Cross-section at AA in the middle.

[0031] Figure 3 Shown is a side view of a reduction transmission device according to an embodiment of the present application.

[0032] Figure 4 Shown Figure 3Cross-section at BB.

[0033] Figure 5 Shown is a three-dimensional view of a reduction transmission device according to an embodiment of the present application.

[0034] Figure 6 Shown is a three-dimensional view of the friction wheel of the reduction transmission device according to an embodiment of the present application, wherein a pre-tightening assembly is shown.

[0035] Figure 7 Shown is a three-dimensional view of the friction wheel of the reduction transmission device according to an embodiment of the present application from another angle.

[0036] Figure 8 Shown is a three-dimensional view of a pressure member of a reduction transmission device according to an embodiment of the present application.

[0037] Reference numerals:

[0038] Driving wheel shaft 10, transmission assembly 20, friction wheel 21, guide cavity 211, first guide surface 212, hollow groove 213, first shaft hole 214, fixing member 30, output member 40, first stop member 41, boss 42, second limiting groove 43, gasket 44, pin 45, first support bearing 50, preload assembly 60, elastic member 61, pressure member 62, first sub-section 621, second sub-section 622, third sub-section 623, second guide surface 624, first radial bearing 70, second stop member 71, second radial bearing 72, axial support portion 721, second support bearing 73, planetary carrier cover plate 74, connecting member 741, fastening pin 75, rotor 76, sleeve portion 761, housing 80, rear end cover 81. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0040] The disclosure below provides many different embodiments or examples for implementing different configurations of the present invention. To simplify the disclosure of the present invention, the components and configurations of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations discussed.

[0041] For ease of description, spatially relative terms may be used herein to describe the relative position or movement of one element or feature relative to another element or feature as shown in the figures, such as "inside," "outside," "inside," "outside," "below," "beneath," "above," "above," "front," "back," and the like. Such spatially relative terms are intended to include different orientations of the device in use or operation other than the orientation depicted in the figures. For example, if the device in the figures undergoes a positional flip or a change in posture or a change in motion, then these directional indications will also change accordingly. For example, an element described as "below" or "below" another element or feature will subsequently be oriented as "above" or "above" another element or feature. Thus, the example term "below" can include both above and below orientations. The device may be oriented otherwise (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein will be interpreted accordingly.

[0042] like Figures 1-4 As shown, the reduction transmission device according to an embodiment of the present application includes: a driving wheel shaft 10, a transmission assembly 20, a fixing member 30 and an output member 40.

[0043] Specifically, the driving wheel shaft 10 is capable of rotating around its central axis; the transmission assembly 20 includes at least one rotatable friction wheel 21, and the at least one friction wheel 21 is arranged along the circumference of the driving wheel shaft 10 and abuts and frictionally contacts the outer peripheral surface of the driving wheel shaft 10; the fixing member 30 abuts and frictionally contacts the outer peripheral surface of the friction wheel 21, so that the friction wheel 21 can revolve around the central axis of the driving wheel shaft 10 driven by the friction force of the driving wheel shaft 10; the transmission assembly 20 is connected to the output member 40 to drive the output member 40 to rotate, wherein the rotation speed of the output member 40 is less than the rotation speed of the driving wheel shaft 10.

[0044] To elaborate, when the driving wheel shaft 10 rotates around the central axis, its outer peripheral surface contacts the outer peripheral surface of the friction wheel 21 through friction, thereby generating tangential friction force. The rotational power of the driving wheel shaft 10 is transmitted to the friction wheel 21 through friction force, driving the friction wheel 21 to rotate around its own axis. At this time, the rotation direction of the friction wheel 21 is opposite to the rotation direction of the driving wheel shaft 10, and the fixing part 30 abuts against and maintains friction contact with the outer peripheral surface of the friction wheel 21. Since the fixing part 30 remains stationary, when the friction wheel 21 rotates, the contact point between its outer peripheral surface and the fixing part 30 generates resistance due to friction, which applies tangential constraint to the friction wheel 21. At the same time, the friction wheel 21 is subjected to the combined action of the friction force of the driving wheel shaft 10 and the resistance of the fixing part 30 while rotating, and is forced to revolve around the central axis of the driving wheel shaft 10. Since the friction wheel 21 is transmission-connected to the output part 40, the linear velocity of the friction wheel 21's revolution is less than the linear velocity of the driving wheel shaft 10's rotation, thereby achieving a deceleration effect in which the rotation speed of the output part 40 is less than the rotation speed of the driving wheel shaft 10.

[0045] In the above-described embodiment, the driving wheel shaft 10 is typically cylindrical or stub-shaped, with a central axial hole for fixed connection to a drive motor, or directly connected to the drive motor via a sleeve. The drive motor is used to drive the driving wheel shaft 10 to rotate about its own axis. The outer circumference of the driving wheel shaft 10 can be a smooth cylindrical surface, or can be provided with evenly distributed protrusions to increase the coefficient of friction with the friction wheel 21. The driving wheel shaft 10 is typically located at the center of the reduction gear transmission, and its central axis can be the main rotation axis of the reduction gear transmission. For example, the rotational axis of the output member 40 is collinear with the central axis of the driving wheel shaft 10.

[0046] The transmission assembly 20 includes at least one friction wheel 21. The number of friction wheels 21 can be one, two, three, four, five, or six. Each friction wheel 21 is an independent rotating body, typically in the shape of a short cylinder. The outer surface of the friction wheel 21 is also a smooth cylindrical surface, or it may be provided with raised points that match the outer surface of the driving wheel shaft 10 to increase the friction coefficient between the friction wheel 21 and the driving wheel shaft 10, or the outer surface of the friction wheel 21 may be provided with a polyurethane elastic layer to increase the friction coefficient between the friction wheel 21, the driving wheel shaft 10, and the fixed member 30.

[0047] When the number of friction wheels 21 is greater than one, the multiple friction wheels 21 are evenly distributed around the driving wheel shaft 10. For example, when the transmission assembly 20 includes three friction wheels 21, the central angles between the three friction wheels 21 are 120°.

[0048] The central axis of the friction wheel 21 is parallel to the central axis of the driving wheel shaft 10 and maintains a fixed distance therebetween. The outer circumference of each friction wheel 21 is in tangential contact with the outer circumference of the driving wheel shaft 10, and the other side of its outer circumference is in tangential contact with the inner circumference of the fixing member 30.

[0049] The diameter of the friction wheel 21 can be smaller than the diameter of the driving wheel shaft 10, or equal to the diameter of the driving wheel shaft 10, or larger than the diameter of the driving wheel shaft 10. Figure 2 and Figure 4 As shown, in a specific embodiment of the present application, the diameter of the friction wheel 21 is larger than the diameter of the driving wheel shaft 10. When the driving wheel shaft 10 is in friction contact with the outer circumference of the friction wheel 21, the linear speed of the contact points is equal. Due to the larger diameter of the friction wheel 21, its rotation speed will be lower than the driving wheel shaft 10. At the same time, the trajectory radius of the friction wheel 21 revolving around the central axis of the driving wheel shaft 10 is correspondingly increased, and the linear speed of the revolution is further lower than the linear speed of the rotation of the driving wheel shaft 10, thereby significantly increasing the reduction ratio. At the same time, the large diameter of the friction wheel 21 increases the contact radius of its outer circumference with the fixed part 30. Under the same positive pressure, the friction resistance torque increases accordingly, and the upper limit of the tolerable output torque is increased, reducing the probability of slipping during overload, and improving the load-bearing capacity of the transmission assembly 20. In addition, the stability of the revolution of the friction wheel 21 can be further enhanced to avoid swinging or offset caused by too small a diameter, especially under high load conditions, a more accurate reduction ratio can be maintained.

[0050] like Figure 2 and Figure 4 As shown, the fixing member 30 is an annular frame structure or an annular shell. The central axis of the fixing member 30 is coaxial with the central axis of the driving wheel shaft 10, and its inner circumference is a smooth cylindrical surface or is provided with evenly distributed protrusions that match the outer circumference of the friction wheel 21, thereby increasing the friction coefficient between the fixing member 30 and the friction wheel 21.

[0051] The fixing part 30 is sleeved on the outside of the friction wheel 21, and its inner circumference is in tangential contact with the outer circumference of each friction wheel 21, and together with the outer circumference of the driving wheel shaft 10, it forms constraints on both sides of the friction wheel 21. The driving wheel shaft 10 drives the friction wheel 21 to rotate, and the fixing part 30 limits the radial separation of the friction wheel 21 through friction force, thereby forcing the friction wheel 21 to revolve along the central axis of the driving wheel shaft 10.

[0052] like Figure 1 and Figure 2 As shown, the output member 40 is a disc-shaped or annular plate-shaped structure. The output member 40 is located on one or both axial sides of the driving wheel shaft 10, and its central axis coincides with the central axis of the driving wheel shaft 10. The revolution of the friction wheel 21 drives the output member 40 to rotate synchronously around the central axis of the driving wheel shaft 10.

[0053] The reduction transmission device further includes a housing 80 , and the fixing member 30 can be fixedly connected to the housing 80 by means of bolts or welding, so as to remain stationary.

[0054] According to the reduction transmission device of the embodiment of the present application, the friction wheel 21 is in friction contact with the driving wheel shaft 10 and the fixing part 30. The rotation and revolution of the friction wheel 21 are both transmitted by friction force. There is no gear tooth meshing structure, which avoids the generation of tooth gap. The theoretical backlash can reach zero, avoiding the problem of positioning accuracy attenuation caused by backlash. There is no tooth gap and backlash during the transmission process. During reversing, the friction force changes synchronously with the rotation direction of the driving wheel shaft 10, which has faster response, greatly reduces impact load, and extends the fatigue life of the transmission component 20. It can maintain stable friction force and reduction ratio, and there is no need to rely on complex algorithms to compensate for backlash in real time. In addition, there is no need to deal with the phase lag caused by meshing gap, which reduces the dependence on high-computing power chips and simplifies the control system design and cost.

[0055] In addition, since the transmission of power relies on the friction between the friction wheel 21 and the driving wheel shaft 10, the allowable output torque needs to be less than the friction resistance torque generated by the friction between the friction wheels 21. If the torque at the load end is greater than the friction resistance torque, slippage will occur between the friction wheels 21, and then there will be no power output, thereby preventing the transmission component 20 from bearing destructive loads due to overload. At the same time, the power transmission can be automatically restored. When the load torque falls below the friction resistance torque, the friction force can automatically restore the power transmission without the need for additional clutch or sensor intervention, thereby simplifying the structural design and reducing costs.

[0056] like Figure 2 As shown, the reduction transmission device according to the embodiment of the present application further includes a first support bearing 50, a pin shaft 45 is provided on the output member 40, and the first support bearing 50 and the friction wheel 21 are sequentially sleeved on the outer side of the pin shaft 45 along the radial direction.

[0057] The inner ring of the first support bearing 50 has an interference fit with the pin 45, and the outer ring has a clearance fit with the central axis hole of the friction wheel 21, so that the friction wheel 21 can rotate freely around the pin 45 and bear the radial load through the outer ring of the bearing. When the driving wheel shaft 10 rotates around the central axis, its outer peripheral surface and the outer peripheral surface of the friction wheel 21 frictionally contact to generate tangential friction force, driving the friction wheel 21 to rotate around the pin 45. At this time, the rolling element of the first support bearing 50 rolls between the inner and outer rings, converting the sliding friction of the friction wheel 21 into rolling friction. Friction significantly reduces rotational resistance and wear; when the friction wheel 21 revolves, the friction wheel 21 sleeved on the pin 45 generates a circumferential thrust on the pin 45 through the outer ring of the first support bearing 50. Because the friction wheel 21 tries to drive the pin 45 to move together when revolving, and since the pin 45 is fixed to the output member 40, the thrust pushes the output member 40 to rotate synchronously around the central axis of the driving wheel shaft 10. At the same time, the rotation of the friction wheel 21 around the pin 45 is driven by the friction force of the driving wheel shaft 10, and is independent of the revolving motion.

[0058] In the above embodiment, the pin 45 may be a solid cylindrical rod, the length of which is greater than the axial thickness of the friction wheel 21 , and one end of the pin 45 may be welded and fixed to the output member 40 , while the other end may be suspended.

[0059] The inner ring of the first support bearing 50 is sleeved over the pin 45 and has an interference fit with the pin 45. The outer ring has a clearance fit with the central axis hole of the friction wheel 21. The rolling elements are filled between the inner and outer rings to support the radial load of the friction wheel 21 and reduce the rotational resistance. The first support bearing 50 can be a deep groove ball bearing or a needle roller bearing.

[0060] In a specific embodiment of the present application, the first support bearing 50 is a needle roller bearing. The radial cross-section of the needle roller bearing is small, which reduces the diameter of the central axis hole of the friction wheel 21 accordingly, thereby shortening the cantilever bending moment of the friction wheel 21 during revolution, thereby improving the structural deformation resistance. At the same time, compared with deep groove ball bearings, the needle roller bearing has a stronger radial load-bearing capacity and is more suitable for structures such as the friction wheel 21 that transmit power through friction.

[0061] The reduction transmission device according to the embodiment of the present application ensures that the revolution power of the friction wheel 21 is transmitted to the output member 40 while preventing interference between the rotation and revolution of the friction wheel 21, ultimately achieving zero or low backlash reduction transmission. The fixed connection of the pin 45 ensures the rigid linkage between the output member 40 and the revolution of the friction wheel 21, improving transmission accuracy and load-bearing capacity. The provision of the first support bearing 50 replaces sliding friction with rolling friction, reducing the rotational resistance torque of the friction wheel 21, reducing energy loss and improving transmission efficiency. At the same time, the radial support of the first support bearing 50 ensures the stability of the axis position of the friction wheel 21 during revolution, avoiding uneven contact pressure caused by radial offset, and maintaining a constant friction force between the driving wheel shaft 10 and the friction wheel 21, thereby ensuring a stable reduction ratio and zero or low backlash.

[0062] like Figure 2 and Figure 6 As shown, the reduction transmission device according to the embodiment of the present application further includes a pre-tightening assembly 60 .

[0063] Specifically, the preload assembly 60 includes an elastic member 61 and a pressure member 62. The elastic member 61 is in a compressed state and connected to the pressure member 62. The pressure member 62 can generate a force on the friction wheel 21 or the fixing member 30 to press the two against each other along the normal direction of the contact surface.

[0064] To elaborate, the compressive force of the elastic member 61 acts on the friction wheel 21 or the fixed member 30 through the pressure member 62, so that the two are pressed against each other along the normal direction of the contact surface. When the driving wheel shaft 10 rotates, the friction force generated by the pre-tightening between its outer peripheral surface and the outer peripheral surface of the friction wheel 21 drives the friction wheel 21 to rotate, and at the same time, the fixed member 30 is kept in contact with the outer peripheral surface of the friction wheel 21 under the action of the pre-tightening force; when the friction wheel 21 has a radial offset due to processing errors, or as the surfaces of the friction wheel 21, the driving wheel shaft 10 and the fixed member 30 wear, the elastic member 61 is released and automatically extends, pushing the pressure member 62 to continuously apply a pressing force to the friction wheel 21 or the fixed member 30, compensating for the increase in the gap caused by wear, maintaining a constant positive pressure on the contact surface, ensuring that the friction force is always greater than the transmission torque without slipping, and making the contact pressure between the friction wheel 21 and the driving wheel shaft 10 and the fixed member 30 always in an adaptive adjustment state during the transmission process.

[0065] In the above-mentioned embodiment, the elastic member 61 can be a helical cylindrical compression spring, or other spring structures such as a butterfly spring, a diaphragm spring, a wave spring, etc. The free length of the elastic member 61 is greater than the installation length, which makes the elastic member 61 always in a compressed state. One end of the elastic member 61 can be fixed on the housing 80, or fixed on the end face of the output member 40, and the other end is in contact with the pressure member 62, which can be arranged on the radial outside of the fixing member 30.

[0066] The pressure member 62 can be a cylindrical push rod or an L-shaped pressure plate, the end of which is flat, which is convenient for fitting with the surface of the friction wheel 21 or the fixing member 30. A spring mounting groove can be set in the pressure member 62. The pressure member 62 is installed between the friction wheel 21 and the output member 40, or between the fixing member 30 and the housing 80. The axis of the pressure member 62 is radially aligned with the friction wheel 21 or has a certain angle, and can move radially or along a straight line at a certain angle to the radial direction.

[0067] Exemplarily, the pressure member 62 is a cylindrical push rod, which abuts against the fixing member 30 . The axis of the elastic member 61 coincides with the radial direction of the friction wheel 21 , and one end thereof abuts against the housing 80 .

[0068] like Figure 2 and Figure 8As shown, in some embodiments, a guide cavity 211 is provided on the friction wheel 21, and the axis of the guide cavity 211 has an angle ɑ with the axis of the friction wheel 21, 0°≤ɑ<90°, and the pressure piece 62 is provided in the guide cavity 211 and can move along the axial direction of the guide cavity 211, and the guide cavity 211 has a first guide surface 212, and the first guide surface 212 is inclined from the inside of the guide cavity 211 to the outside of the guide cavity 211 in a direction gradually away from the axis of the guide cavity 211, and the pressure piece 62 has a second guide surface 624, and the second guide surface 624 is in contact with the first guide surface 212, and the elastic piece 61 abuts against the outward end surface of the pressure piece 62.

[0069] The axis of the guide cavity 211 forms an angle ɑ with the axis of the friction wheel 21, where 0°≤ɑ<90°, where ɑ can be 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, and 85°, etc. By setting different ɑ values, the guide cavity 211 can be reasonably arranged even when the axial space of the friction wheel 21 is different.

[0070] The guide cavity 211 is a blind hole structure. The outer opening of the guide cavity 211 is located on one end face of the friction wheel 21. The inner end of the guide cavity 211 is closed to limit the axial movement range of the pressure member 62. Its axis is parallel to the axis of the friction wheel 21 itself or at a certain tilt angle. For example, if it is located on the end face of the side close to the output member 40, the other end of the elastic member 61 abuts against the output member 40. The first guide surface 212 of the inner wall of the guide cavity 211 is inclined from the inside to the outside toward the direction away from the axis of the guide cavity 211, and the pressure member 62 is embedded in the guide cavity 21. 1, the second guide surface 624 is in contact with the first guide surface 212, and the elastic member 61 abuts against one end of the outer side of the pressure-applying member 62 and applies a compressive force along the axial direction of the guide cavity 211. This force is decomposed by the inclined first guide surface 212 into a radial pressing force perpendicular to the outer circumference of the friction wheel 21 and a force along the axis of the guide cavity 211. The radial pressing force causes the friction wheel 21 to expand and deform radially, forcing the contact area between the outer circumference of the friction wheel 21 and the driving wheel shaft 10 and the fixing member 30 to increase, making the contact pressure more evenly distributed, and significantly improving the stability of the friction force and the smoothness of the transmission.

[0071] When the friction surface wears and causes the gap to increase, the elastic member 61 stretches due to the release of compression, pushing the pressure member 62 to slide further along the axial direction of the cavity toward the closed end. The outward-expanding second guide surface 624 of the pressure member 62 forces the first guide surface 212 of the friction wheel 21 to move synchronously toward the outer peripheral surface of the friction wheel 21, driving the radial expansion deformation of the friction wheel 21 to increase accordingly, thereby compensating for the gap.

[0072] In addition, the first guide surface 212 and the second guide surface 624 are provided to fit each other so that the friction wheel 21 and the fixing member 30 are pressed tightly together, so that a smaller axial elastic compression amount can produce a larger radial pressing effect, thereby amplifying the thrust of the elastic member 61. At the same time, since the contact surface between the pressure member 62 and the friction wheel 21 is larger, the radial force on the friction wheel 21 can be made more uniform.

[0073] The following example is taken when the axis of the guide cavity 211 is parallel to the axis of the friction wheel 21, that is, ɑ=0°. The axis of the friction wheel 21 is the horizontal x-axis, the axial force Fa points to the left along the x-axis, and the angle between the first guide surface 212 or the second guide surface 624 and the X-axis is β. The axial force Fa pushes the pressure member 62 to squeeze the first guide surface 212. The first guide surface 212 will generate a reaction force N perpendicular to itself. At this time, N can be decomposed into an x-axis component, which is balanced with Fa and has a magnitude of N·cosβ, and a y-axis component, which is perpendicular to the x-axis and has a magnitude of N·sinβ. Since the pressure member 62 is subjected to balanced force in the x-axis direction, Fa=N·cosα. Substituting it into the conversion Fr=Fa·tanα, it can be seen intuitively that the radial force Fr is amplified compared to Fa.

[0074] In the above embodiment, the guide cavity 211 is a cylindrical blind hole provided on one side of the pin 45 , or an annular blind hole provided around the pin 45 .

[0075] The first guide surface 212 is a conical surface, and the pressure piece 62 is a truncated cone, which is hollow inside for the installation of the elastic piece 61. The diameter of the small end of the pressure piece 62 is not equal to 0, and the diameter of the large end of the pressure piece 62 is the same as the maximum inner diameter of the guide cavity 211. The outer surface of the pressure piece 62 is provided with a second guide surface 624, and the second guide surface 624 is a conical surface that is completely in contact with the first guide surface 212.

[0076] The guide cavity 211 is an annular blind hole, disposed around the pin 45. The pressure member 62 can also be formed into an annular thin plate, comprising a first sub-portion 621, a second sub-portion 622, and a third sub-portion 623, which are sequentially bent and connected. The first sub-portion 621 is perpendicular to the axial direction of the friction wheel 21. The outer wall of the second sub-portion 622 is provided with a second guide surface 624. The third sub-portion 623 extends along the wall of the guide cavity 211 and is parallel to the axial direction of the friction wheel 21. The first sub-portion 621 is located further inward of the guide cavity 211 than the third sub-portion 623. The elastic member 61 presses against the outer side of the first sub-portion 621. The physical structure of the friction wheel 21 defining one side of the annular wall of the guide cavity 211 is formed as a guide column, with a central axial hole provided in the middle of the guide column. The elastic member 61 is sleeved outside the guide column.

[0077] In some embodiments, the pressure member 62 also includes a fourth sub-portion, which is connected to the end of the first sub-portion 621 away from the second sub-portion 622, and extends along the axial direction of the guide cavity 211 and also the axial direction of the friction wheel 21. The fourth sub-portion is in the shape of a sleeve and is sleeved on the guide column, and the elastic member 61 is sleeved outside the fourth sub-portion.

[0078] like Figure 7 As shown, in some embodiments, a hollow groove 213 is further provided on the friction wheel 21 , the opening of the hollow groove 213 is located on one end surface of the friction wheel 21 , and the opening of the guide cavity 211 is located on the other end surface of the friction wheel 21 .

[0079] The opening of the hollow groove 213 and the opening of the guide cavity 211 are respectively located on the end faces on both sides of the axial direction of the friction wheel 21. The opening of the hollow groove 213 faces the side away from the input member and is in the shape of a fan or annular groove. The hollow groove 213 extends to the middle of the friction wheel 21 but does not pass through. The hollow groove 213 can extend along the axial direction of the friction wheel 21 or be inclined at a certain angle to the axial direction. The reduced material of the hollow groove 213 reduces the overall weight of the friction wheel 21 and reduces the moment of inertia. When the speed of the input member changes, the friction wheel 21 responds faster due to the reduced inertia. The pressure member 62 in the guide cavity 211 slides along the axial direction of the guide cavity 21 and amplifies the radial force through the second guide surface 624, causing the friction wheel 21 to expand and deform radially. Due to the reduction of material in the hollow groove 213 area, the radial stiffness of the friction wheel 21 on this side is relatively reduced, and the deformation is increased, so that the overall expansion of the friction wheel 21 is increased and more uniform, thereby improving the expansion effect of the pressure member 62 on the friction wheel 21.

[0080] In the above embodiment, the hollow grooves 213 are fan-shaped and multiple in number. They are centered around the axis of the friction wheel 21 and evenly distributed along the circumference. A certain wall thickness is maintained between the hollow grooves 213 and the outer circumference of the friction wheel 21 to ensure that the friction wheel 21 does not break when subjected to radial force. The multiple walls of the hollow grooves 213 have smooth transitions to reduce stress concentration.

[0081] In the above embodiment, the hollow groove 213 can also be arranged in an annular shape, forming a continuous annular groove, and the solid structure between the hollow groove 213 and the outer peripheral surface of the friction wheel 21 has a uniform axial wall thickness along the hollow groove 213.

[0082] The hollow groove 213 and the guide cavity 211 are staggered by a certain distance in the axial direction, and the two are not connected.

[0083] like Figure 2 and Figure 7 As shown, in some embodiments, the hollow groove 213 is arranged in an annular shape and is located on a side of the guide cavity 211 away from the driving wheel shaft 10 in the radial direction of the friction wheel 21 .

[0084] The hollow groove 213 is annular and arranged around the axis of the friction wheel 21. It is radially located on the side of the guide cavity 211 away from the driving wheel shaft 10. This makes the material on the side of the friction wheel 21 close to the driving wheel shaft 10 denser and has higher radial stiffness, ensuring effective transmission of the clamping force. On the side of the hollow groove 213 away from the driving wheel shaft 10, due to the reduced material, the radial stiffness is relatively low, allowing the friction wheel 21 to undergo moderate elastic deformation in this area, making the overall radial expansion more uniform, avoiding local stress concentration, and effectively clamping the friction wheel 21 and the fixing member 30, eliminating the formation of gaps. At the same time, the hollow groove 213 and the guide cavity 211 are located on opposite sides of the axial space of the friction wheel 21, which can also balance the weight of the friction wheel 21, avoid eccentricity caused by unbalanced loading, and improve transmission smoothness.

[0085] like Figure 2 As shown, in some embodiments, first radial bearings 70 are respectively provided on both sides of the friction wheel 21 in the axial direction, and the first radial bearings 70 on both sides abut against both side end surfaces of the friction wheel 21 respectively.

[0086] When the elastic member 61 applies axial pressure along the guide cavity 211, the force is decomposed by the inclined first guide surface 212, and the axial component force is transmitted to the end face of the friction wheel 21. The inner ring or outer ring of the first radial bearings 70 on both sides directly abuts the end faces of the friction wheel 21 on both sides. The first radial bearings 70 will bear the axial load without causing significant wear. At the same time, since the first radial bearings 70 are symmetrically arranged in the axial direction of the friction wheel 21, the axial component force is balanced on both sides of the friction wheel 21, avoiding the friction wheel 21 from being skewed due to unidirectional force. When the friction wheel 21 rotates, the radial displacement and axial movement are restricted by the first radial bearings 70 on both sides, so that the contact position between the friction wheel 21 and the driving wheel shaft 10 remains stable in the axial direction.

[0087] In the above embodiment, the first radial bearing 70 can be a deep groove ball bearing or a cylindrical roller bearing. The first radial bearing 70 is annular in shape and consists of an inner ring, an outer ring, rolling elements and a cage.

[0088] like Figure 2 As shown, in some embodiments, a planetary carrier cover plate 74 is further provided in the reduction transmission device, and the planetary carrier cover plate 74 and the output member 40 are respectively located on both sides of the axial direction of the friction wheel 21, and the output member 40 is connected to the planetary carrier cover plate 74 through a connecting member 741. A first limiting groove is provided on the planetary carrier cover plate 74 on the side close to the friction wheel 21. The first limiting groove is annular, and one of the first radial bearings 70 is clamped in the first limiting groove. A second limiting groove 43 is provided on the side of the output member 40 close to the friction wheel 21. The second limiting groove 43 is annular and is symmetrically arranged with the first limiting groove. Another first radial bearing 70 is clamped in the second limiting groove 43.

[0089] like Figure 2 As shown, the planetary carrier cover plate 74 is located on the left side of the friction wheel 21, the inner ring end face of the first radial bearing 70 on the left side abuts the bottom plane of the first limiting groove, and its outer ring end face abuts the end face of the friction wheel 21, and the output member 40 is located on the right side of the friction wheel 21, the inner ring of the first radial bearing 70 on the right side abuts the bottom plane of the second limiting groove 43, and its outer ring end face abuts the end face of the friction wheel 21. The outer rings of the first radial bearings 70 on the left and right sides are not fixedly connected to the friction wheel 21 but can maintain close contact, allowing the friction wheel 21 to rotate synchronously with the outer ring. When the pressure member 62 decomposes to generate axial force, the force is transmitted to the outer ring of the first radial bearing 70 through the end face of the friction wheel 21, and is transmitted to the inner ring of the first radial bearing 70 after dispersion by the rolling body, and finally transmitted to the planetary carrier cover plate 74 and the output member 40 by the inner ring end face. Under this cooperation, the inner ring of the first radial bearing 70 is rigidly fixed by the planetary carrier cover plate 74 through the first limiting groove, and is rigidly fixed by the output member 40 through the second limiting groove 43. The outer rings of the first radial bearings 70 on the left and right sides only generate rolling friction when rotating with the friction wheel 21, and the friction coefficient is extremely low. It not only bears the axial force to avoid its direct effect on the friction wheel 21 body, maintains the stability of the axial position, but also ensures the flexibility of the rotation of the friction wheel 21, ensuring the transmission accuracy and efficiency.

[0090] In the above-mentioned embodiment, the inner ring of the first radial bearing 70 includes a main body portion abutting against the bottom plane of the limiting groove (the first limiting groove or the second limiting groove 43) and a limiting portion connected to the main body portion. The limiting portion is arranged in a ring shape and extends along the circumferential direction of the limiting groove and abuts against the circumferential side wall of the limiting groove. The limiting portion is clamped at the radial outer end of the outer ring of the first radial bearing 70.

[0091] like Figure 2 As shown, in the above embodiment, the depth of the first limiting groove in the axial direction of the friction wheel 21 is slightly smaller than the thickness of the first radial bearing 70 in the axial direction.

[0092] like Figure 2As shown, there is an axial gap between the output member 40 and the friction wheel 21 to prevent interference between them. The depth of the second limiting groove 43 in the axial direction of the friction wheel 21 is greater than the axial thickness of the first radial bearing 70 on the right side. A gasket 44 is sandwiched between the bottom plane of the second limiting groove 43 and the inner ring of the first radial bearing 70. One end of the elastic member 61 extending out of the guide cavity 211 abuts the outer ring of the first radial bearing 70 on the right side. This allows the outer ring of the first radial bearing 70 on the right side to both withstand axial force transmission and allow slight axial displacement of the friction wheel 21 due to speed fluctuations or thermal expansion, thereby avoiding jamming caused by rigid contact. At the same time, the elastic member 61 can buffer and absorb fluctuations in the axial force of the pressure member 62, reducing the impact load between the first radial bearing 70 and the friction wheel 21. The elastic force can maintain the contact stiffness between the friction wheel 21 and the outer ring of the first radial bearing 70 on the right side, ensuring that the outer ring of the first radial bearing 70 on the right side rotates synchronously with the friction wheel 21, while also relieving radial runout stress through the gap between the outer ring of the first radial bearing 70 and the friction wheel 21.

[0093] Among them, the thickness of the gasket 44 can be set to different specifications as needed, thereby changing the compression amount of the elastic member 61, thereby adjusting the preload force of the elastic member 61 and adjusting the friction force between the friction wheel 21 and the driving wheel shaft 10 and the fixing member 30.

[0094] In the above embodiment, the first radial bearing 70 may be a deep groove ball bearing or a needle roller bearing. Figure 2 In the embodiment shown, the first radial bearing 70 is a needle roller bearing. The rolling elements of the needle roller bearing are slender needle rollers with a smaller radial cross-section. In scenarios where the installation space on both sides of the friction wheel 21 is limited, axial support can be achieved with a more compact structure to avoid interference with surrounding structures. The needle rollers are in line contact with the inner and outer rings. Compared with the point contact of deep groove ball bearings, the axial force decomposed by the pressure member 62 can be dispersed and transmitted through a larger contact area, reducing the extrusion deformation of the outer ring and the end face of the friction wheel 21, improving the load-bearing stiffness and service life of the first radial bearing 70, and can more accurately limit the axial movement of the friction wheel 21, especially keeping the axial position of the friction wheel 21 stable during high-speed rotation.

[0095] like Figure 2 and Figure 7 As shown, in some embodiments, a first axial hole 214 is provided on the output member 40, the driving wheel shaft 10 is passed through the first axial hole 214, a first stop member 41 is further provided in the first axial hole 214, a second stop member 71 is provided on the driving wheel shaft 10, the second stop member 71 is located on the side of the first stop member 41 away from the friction wheel 21, and a second radial bearing 72 is sandwiched between the second stop member 71 and the first stop member 41.

[0096] The first stop member 41 is provided in the first shaft hole 214 of the output member 40, the driving wheel shaft 10 is passed through the first shaft hole 214 and a second stop member 71 is fixed on the driving wheel shaft 10. When the axial component of the pressure member 62 acts on the friction wheel 21 to push the driving wheel back, the direction of the force is away from the friction wheel 21, that is, toward the side away from the friction wheel 21. Therefore, the second stop member 71 is provided on the side of the first stop member 41 away from the friction wheel 21. The inner ring of the second radial bearing 72 is interference fit with the driving wheel shaft 10 and abuts the end surface of the second stop member 71. When the axial component of the pressure member 62 acts on the friction wheel 21 and reacts to the driving wheel shaft 10 through friction contact, the force pushes the inner ring of the second radial bearing 72 through the second stop member 71, and the load is dispersed to the outer ring through the rolling element and is borne by the first stop member 41, so as to prevent the driving wheel from moving or deforming due to the axial force, and ensure that the driving wheel maintains a stable position under the action of the axial component of the force.

[0097] The first stopper 41 may be an annular retaining ring or a step structure, and the second stopper 71 may be a shaft shoulder or a retaining ring. In some embodiments, the first stopper 41 is formed as a step structure and is fixedly connected to the output member 40 .

[0098] like Figure 2 As shown, in some embodiments, a second support bearing 73 is further provided in the first shaft hole 214, and the second radial bearing 72 includes an inner ring, an outer ring and a rolling element, the inner ring abuts against the second stop member 71, and the outer ring abuts against the first stop member 41, the inner ring includes a radial end and an axial support portion 721 connected to the radial end and extending along the axial direction of the driving wheel shaft 10, the radial end abuts against one side of the second support bearing 73, and the axial support portion 721 is clamped between the driving wheel shaft 10 and the second support bearing 73.

[0099] The axial support portion 721 is an annular cylindrical structure that extends from the radial end of the inner ring of the second radial bearing 72 along the axial direction of the driving shaft 10. Its inner wall maintains a clearance fit with the outer circumference of the driving shaft 10. The cylindrical extension direction of the axial support portion 721 is parallel to the axis of the driving shaft 10, with a uniform radial thickness. Its end face transitions perpendicularly to the radial end, forming an L-shaped structure with the radial end. The axial support portion 721 of the inner ring of the second radial bearing 72 is inserted into the gap between the inner ring of the second support bearing 73 and the driving shaft 10.

[0100] When the axial component of the force exerted by the pressure member 62 on the driving wheel is transmitted to the inner ring of the second radial bearing 72 via the second stop member 71, the force pushes the inner ring of the second support bearing 73 through the radial end, and is then transmitted to the inner wall of the first shaft hole 214 via the rolling element of the second support bearing 73, thereby dispersing the axial load. This can not only suppress the movement caused by the axial force, but also jointly limit the radial deviation of the driving wheel shaft 10, thereby reducing radial runout during rotation.

[0101] like Figure 1 and Figure 2 As shown, in some embodiments, the second stop member 71 also serves as a dustproof end cover, and a fastening hole extending along the axial direction of the driving wheel shaft 10 is provided at one end of the driving wheel shaft 10 close to the output member 40, and a fastening pin 75 is provided in the fastening hole, which fixes the second stop member 71 to the driving wheel shaft 10.

[0102] like Figure 2 and Figure 4 As shown, in some embodiments, the reduction transmission device further includes a planet carrier cover plate 74 .

[0103] Specifically, the planetary carrier cover plate 74 and the output member 40 are respectively arranged on both sides of the friction wheel 21. The planetary carrier cover plate 74 is provided with a second axial hole, and the driving wheel shaft 10 is passed through the second axial hole. The output member 40 is provided with a boss 42, and the boss 42 and the friction wheel 21 are spaced apart along the circumference of the driving wheel shaft 10. A connecting member 741 is passed through the planetary carrier cover plate 74, and the connecting member 741 is threadedly connected to the boss 42.

[0104] The second axial hole provided on the planet carrier cover plate 74 is for the driving wheel shaft 10 to pass through, so that the axis of the driving wheel shaft 10 is parallel to the axis of the friction wheel 21, ensuring that the radial force of the driving wheel shaft 10 and the friction wheel 21 are uniform when they contact. The boss 42 and the friction wheel 21 are spaced apart in the circumferential direction of the driving wheel shaft 10 to avoid direct contact and interference between the two. After the planet carrier cover plate 74 and the output member 40 are fixed by the connecting member 741, they cooperate with the first radial bearings 70 on both sides to form an axial clamping for the friction wheel 21, stably constraining the friction wheel 21 in the middle position.

[0105] When the connecting member 741 is assembled with the boss 42 , the compression amount of the elastic member 61 can be accurately controlled by continuously adjusting the screw-in depth, thereby adjusting the force of the pressure member 62 acting on the friction wheel 21 .

[0106] like Figure 2 As shown, in some embodiments, the reduction transmission device further includes a rotor 76 and a rear end cover 81. The rotor 76 includes a sleeve portion that is sleeved on and fixedly connected to the driving wheel shaft 10. The sleeve portion is located on the side of the planet carrier cover plate 74 facing away from the friction wheel 21. Two third support bearings are provided on the sleeve portion. The rear end cover 81 and the planet carrier cover plate 74 are located on either side of the sleeve portion and sleeved outside the third support bearings. The rear end cover 81 and the planet carrier cover plate 74 are fixedly connected to the housing 80 via fasteners.

[0107] The joint module according to the embodiment of the present application includes the above-mentioned reduction transmission device.

[0108] The joint module according to the embodiment of the present application has all the advantages of the above-mentioned reduction transmission device, which will not be described in detail here. The joint module includes a drive motor, which is connected to the driving wheel shaft in a transmission manner.

[0109] The robot system according to the embodiment of the present application includes a moving component and the above-mentioned reduction transmission device, and the output member 40 of the reduction transmission device is in transmission connection with the moving component.

[0110] According to the robot system of the embodiment of the present application, during the transmission process of the reduction transmission device, the transmission of power relies on the friction between the friction wheel and the driving wheel shaft. The allowable output torque needs to be less than the friction resistance torque generated by the friction force between the friction wheels. If the torque at the load end is greater than the friction resistance torque, slippage will occur between the friction wheels, and then there will be no power output, thereby preventing the transmission component from bearing destructive loads due to overload. At the same time, the power transmission can be automatically restored. When the load torque falls below the friction resistance torque, the friction force can automatically restore the power transmission without the need for additional clutch or sensor intervention, thereby simplifying the structural design and reducing costs.

[0111] It should be understood that the terms used in the text are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an", etc. as used in the text may also be represented to include plural forms. The terms "comprise", "include", "contain", and "have" are inclusive and therefore specify the existence of the stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps can be used.

[0112] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0113] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A reduction transmission device, characterized in that: include: The driving wheel shaft is capable of rotating around its central axis; a transmission assembly, the transmission assembly comprising at least one rotatable friction wheel, the at least one friction wheel being arranged along the circumference of the driving wheel shaft and being in abutment and frictional contact with the outer circumference of the driving wheel shaft; a fixing member, the fixing member abutting and frictionally contacting the outer peripheral surface of the friction wheel, so that the friction wheel can revolve around the central axis of the driving wheel shaft under the drive of the friction force of the driving wheel shaft; The output member is connected to the transmission assembly to drive the output member to rotate, wherein the rotation speed of the output member is lower than the rotation speed of the driving wheel shaft.

2. The reduction transmission device according to claim 1, characterized in that: It also includes a first support bearing. The output member is provided with a pin shaft. The first support bearing and the friction wheel are sequentially sleeved on the outer side of the pin shaft along the radial direction.

3. The reduction transmission device according to claim 1, characterized in that: Also includes: The pre-tightening assembly includes an elastic member and a pressure member. The elastic member is in a compressed state and connected to the pressure member. The pressure member can generate a force on the friction wheel or the fixing member so that the two are pressed against each other along the normal direction of the contact surface.

4. The reduction transmission device according to claim 3, characterized in that: A guide cavity is provided on the friction wheel, and the axis of the guide cavity has an angle ɑ with the axis of the friction wheel, 0°≤ɑ<90°. The pressure piece is provided in the guide cavity and can move along the axial direction of the guide cavity. The guide cavity has a first guide surface, and the first guide surface is inclined in a direction from inside the guide cavity to outside the guide cavity in a direction gradually away from the axis of the guide cavity. The pressure piece has a second guide surface, and the second guide surface is in contact with the first guide surface. The elastic piece abuts against the outward end surface of the pressure piece.

5. The reduction transmission device according to claim 4, characterized in that: The friction wheel is further provided with a hollow groove, the opening of the hollow groove is located on one end surface of the friction wheel, and the opening of the guide cavity is located on the other end surface of the friction wheel.

6. The reduction transmission device according to claim 5, characterized in that: The hollow groove is arranged in an annular shape and is located on a side of the guide cavity away from the driving wheel shaft in the radial direction of the friction wheel.

7. The reduction transmission device according to claim 4, characterized in that: First radial bearings are respectively provided on both sides of the friction wheel in the axial direction, and the first radial bearings on both sides are respectively in contact with both side end surfaces of the friction wheel.

8. The reduction transmission device according to claim 4, characterized in that: A first axial hole is provided on the output member, the driving wheel shaft is passed through the first axial hole, a first stop member is also provided in the first axial hole, a second stop member is provided on the driving wheel shaft, the second stop member is located on the side of the first stop member away from the friction wheel, and a second radial bearing is sandwiched between the second stop member and the first stop member.

9. The reduction transmission device according to claim 8, characterized in that: A second support bearing is also provided in the first shaft hole. The second radial bearing includes an inner ring, an outer ring and a rolling element. The inner ring abuts against the second stopper, and the outer ring abuts against the first stopper. The inner ring includes a radial end and an axial support portion connected to the radial end and extending along the axial direction of the driving wheel shaft. The radial end abuts against one side of the second support bearing, and the axial support portion is clamped between the driving wheel shaft and the second support bearing.

10. The reduction transmission device according to claim 4, characterized in that: Also includes: A planetary carrier cover plate, the planetary carrier cover plate and the output member are respectively arranged on both sides of the friction wheel, the planetary carrier cover plate is provided with a second axial hole, the driving wheel shaft is passed through the second axial hole, a boss is provided on the output member, the boss and the friction wheel are spaced apart along the circumference of the driving wheel shaft, a connecting member is passed through the planetary carrier cover plate, and the connecting member is threadedly connected to the boss.

11. A joint module, characterized in that: The invention comprises a reduction transmission device as claimed in any one of claims 1 to 10.

12. A robot system, characterized in that: It comprises a moving component and the reduction transmission device according to any one of claims 1 to 10, wherein the output member of the reduction transmission device is in driving connection with the moving component.

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