Anti-backlash speed reducer

Abstract

The anti-backlash speed reducer comprises an outer wheel and an inner wheel assembly which are coaxially arranged, the inner wheel assembly comprises a driving shaft, the driving shaft is rotationally sleeved with a first gear and a second gear, and the circle center of the first gear and the circle center of the second gear are eccentrically arranged relative to the rotating center of the driving shaft; the fastener is used for selectively fixing the first gear and the second gear to the driving shaft so as to jointly rotate along with the driving shaft, or releasing the first gear and the second gear so as to enable the first gear and the second gear to rotate relative to the driving shaft. According to the anti-backlash speed reducer designed by the invention, the backlash adjuster which can be selectively fixed or rotated relative to the driving shaft is adopted, and the first gear and the second gear are eccentrically arranged on the backlash adjuster, so that a user only needs to release the fixed state of the backlash adjuster when necessary, and the backlash can be eliminated by performing tiny relative rotation adjustment on the backlash adjuster; therefore, the meshing clearance of the first gear and the second gear relative to the inner teeth of the outer wheel can be accurately controlled, and the gear backlash caused by manufacturing tolerance, assembly error or long-term operation abrasion is effectively compensated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of speed reducer, in particular to a backlash elimination speed reducer. BACKGROUND

[0002] In the prior art, as an indispensable key component in the modern industrial field, the speed reducer is widely used in robots, precision machine tools, automation equipment, aerospace and other fields. Its main function is to reduce the speed of the power source such as motor and increase the output torque to meet the needs of different application scenarios. According to the transmission principle and structural characteristics, the common precision speed reducers on the market mainly include planetary reducer, RV reducer and harmonic reducer.

[0003] The planetary reducer is widely used in general industrial fields due to its compact structure, high transmission efficiency and strong carrying capacity. However, the traditional planetary reducer has a problem of large backlash due to the existence of gear meshing gap, which is usually more than 10 arc minutes. In high-precision control applications, such as precision servo systems and robot joints, the backlash will seriously affect the transmission accuracy, positioning accuracy and dynamic response performance, making it difficult to meet the application requirements of high precision and high performance. In addition, when a high-precision planetary reducer is needed, the manufacturing cost and maintenance difficulty will also increase significantly.

[0004] The RV reducer adopts the structure of combining planetary gear pre-reduction with cycloid pin wheel secondary reduction. Compared with the planetary reducer, the RV reducer has significant improvement in rigidity, impact resistance and transmission accuracy, and the backlash can be controlled to be more than 1 arc minute. Therefore, the RV reducer is often applied to fields such as industrial robot joints with high requirements for precision and rigidity. However, the structure of the RV reducer is relatively complex, and the machining precision of the parts is high, resulting in high manufacturing cost and long production cycle, which makes it difficult to meet the needs of large-scale applications.

[0005] The harmonic reducer utilizes the principle of flexible deformation to achieve transmission, and has the advantages of small size, light weight, large transmission ratio and high precision, and the backlash can be controlled to be less than 3 arc minutes, which is particularly suitable for occasions sensitive to size and weight, such as light robots, aerospace aircraft and precision instruments. However, the harmonic reducer also has some inherent shortcomings, such as relatively low rigidity, poor impact resistance, easy fatigue of the flexspline, limited service life, and easy heating during high-speed operation. In addition, the manufacturing cost of the harmonic reducer is also relatively high, and the carrying capacity is limited to a certain extent. INVENTION CONTENTS

[0006] In order to solve the above problems, the present application provides a backlash elimination speed reducer which can actively eliminate backlash.

[0007] In order to achieve the above object, the gap eliminator designed in the application comprises coaxially arranged outer wheel and inner wheel assemblies, wherein the inner wheel assembly comprises:

[0008] a driving shaft, on which a first gear and a second gear are rotatably sleeved, the centers of the first gear and the second gear are arranged in equidistant eccentricity relative to the rotation center of the driving shaft, and the line connecting the centers of the first gear and the second gear passes through the rotation center of the driving shaft;

[0009] a fastener for fixing the first gear and the second gear to the driving shaft to rotate together in the first working state, or releasing the first gear and the second gear to enable the first gear and the second gear to rotate relative to the driving shaft in the second working state;

[0010] wherein the inner periphery of the outer wheel is provided with an inner tooth, the first gear and the second gear jointly constitute a first outer tooth which is in mesh with the inner tooth, and the first outer tooth and the inner tooth have a tooth number difference.

[0011] Further, the application also provides a gap eliminator comprising:

[0012] a third gear and a fourth gear, which are connected and fixed on the driving shaft, the centers of the third gear and the fourth gear are arranged in equidistant eccentricity relative to the rotation center of the driving shaft, and the line connecting the centers of the third gear and the fourth gear passes through the rotation center of the driving shaft;

[0013] wherein the third gear and the fourth gear jointly constitute a second outer tooth which is in mesh with the inner tooth, the second outer tooth and the first outer tooth are of the same size; the long axis of the first outer tooth and the long axis of the second outer tooth are arranged in parallel or in a predetermined angle in the normal projection on the driving shaft axial direction.

[0014] Further, the inner wheel assembly further comprises a gap adjuster, which is sleeved on the driving shaft and can rotate relative to the driving shaft; the first gear and the second gear are connected and fixed on the gap adjuster in equidistant eccentricity along the axial direction of the driving shaft; the fastener is arranged on the gap adjuster, and is used to fix the first gear and the second gear to the driving shaft in the first working state or release the first gear and the second gear in the second working state through the gap adjuster.

[0015] Further, the drive shaft has an exposed portion extending out of the spacer, the fastener is threadedly connected with the exposed portion and has a pressing sleeve extending towards the spacer; the inner diameter of the pressing sleeve is unidirectionally increased towards the side away from the fastener in the axial direction of the drive shaft, and a tapered pressing space is formed between the outer periphery of the drive shaft and the inner wall of the pressing sleeve; one end of the spacer extends at least partially into the tapered pressing space; when the fastener is tightened, the pressing sleeve exerts radial pressure on the spacer, so that the spacer is connected and fixed with the drive shaft.

[0016] Further, the end of the spacer extending into the tapered pressing space is provided with a guide inclined surface matched with the inner wall of the pressing sleeve, and a plurality of deformation notches extending in the axial direction of the spacer are formed in the guide inclined surface, so that the end of the spacer can be elastically deformed when subjected to radial pressure.

[0017] Further, the outer surface of the fastener is provided with a first groove structure, and the end of the deformation notch is provided with a second groove structure, both of which are used for the external tool to be screwed.

[0018] Further, the first gear and the second gear are provided with through holes in the overlapping part of the orthographic projection in the axial direction of the drive shaft, and the synchronization rod passes through the through holes, so that the first gear and the second gear can be synchronously rotated.

[0019] Further, the first bearing, the first base and the second base opposite to the first base are further included, one end of the drive shaft passes through the first base and is inserted into the inner ring of the first bearing through the spacer, the outer ring of the first bearing is connected and fixed on the second base, and the first gear and the second gear are located between the first base and the second base; the synchronization rod is provided with a plurality of synchronization rods and has opposite first ends and second ends, the synchronization rod located on the rear side in the circumferential direction of the drive shaft is integrally formed with the first base through the first end, and the synchronization rod located on the front side in the circumferential direction of the drive shaft is integrally formed with the second base through the second end; the first base is provided with a first insertion hole matched with the first end of the synchronization rod on the second base, and the second base is provided with a second insertion hole matched with the second end of the synchronization rod on the first base.

[0020] Further, the second end of the synchronization rod on the first base is provided with a screw hole penetrating through the second base, and the second base is threadedly connected with the screw hole of the synchronization rod on the first base through a fastening screw.

[0021] Further, the first base and the second base are provided with a second bearing coaxial with the outer wheel, and the outer ring of the second bearing is fixed on the inner circumferential surface of the outer wheel.

[0022] The gap-eliminating speed reducer designed in the application adopts a gap adjuster selectively fixed or rotated relative to the driving shaft, and a first gear and a second gear are eccentrically arranged on the gap adjuster, so that the user only needs to release the fixed state of the gap adjuster when necessary, and the meshing gap of the first gear and the second gear relative to the inner teeth of the outer wheel can be accurately controlled by slightly rotating the gap adjuster, thereby effectively compensating for the tooth side gap caused by manufacturing tolerance, assembly error or long-term running wear; at the same time, by directly making the first gear and the second gear as the outer tooth structure meshing with the inner teeth on the inner circumferential surface of the outer wheel, the intermediate link in the traditional multi-stage gear transmission chain is omitted, and the transmission path is more direct, which helps to realize a highly compact overall structure and lightweight design. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a perspective structural schematic diagram of the gap-eliminating speed reducer provided by the application.

[0024] Figure 2 is a perspective exploded view of Figure 1 .

[0025] Figure 3 is a structural schematic diagram of the gap adjuster provided by the application.

[0026] Figure 4 is a planar structural schematic diagram of the gap-eliminating speed reducer provided by the application Figure 1 .

[0027] Figure 5 is a sectional view of Figure 4 at A-A.

[0028] Figure 6 is a sectional view of Figure 4 at B-B.

[0029] Figure 7 is an enlarged schematic diagram of Figure 5 at C.

[0030] Figure 8 is a planar structural schematic diagram of the gap-eliminating speed reducer provided by the application Figure 2 .

[0031] Figure 9 is an enlarged schematic diagram of Figure 8 at D-D.

[0032] The outer wheel 10, the inner tooth 11, the inner wheel assembly 20, the driving shaft 21, the exposed part 211, the first gear 22, the second gear 23, the fastener 24, the pressing sleeve 241, the conical pressing space 242, the first slot structure, the first external tooth 25, the gap adjuster 26, the guide inclined surface 261, the deformation gap 262, the second slot structure 263, the through hole 27, the synchronous rod 28, the first bearing 31, the first base 32, the first insertion hole 321, the second base 33, the second insertion hole 331, the second bearing 35, the third gear 41, and the fourth gear 42. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings, in which it is understood that the preferred embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0034] As shown in Figures 1 to 9 , the gap-eliminating speed reducer provided by the present embodiment mainly comprises an outer wheel 10 and an inner wheel assembly 20 coaxially arranged.

[0035] As shown in Figure 2 , the outer wheel 10 is in the shape of a circular ring, and the inner periphery of the outer wheel 10 is provided with an inner tooth 11. In the present embodiment, the inner tooth 11 preferably adopts a precisely machined hard tooth surface structure to improve the carrying capacity and transmission accuracy. In another example, to improve the carrying capacity and allow a certain deformation to adapt to the meshing, the outer wheel 10 can be made of a synchronous belt-like material, which has flexibility and wear resistance.

[0036] The inner wheel assembly 20 is mainly used to realize transmission in cooperation with the outer wheel 10. Referring to Figures 3 to 5 , the inner wheel assembly 20 mainly comprises a driving shaft 21, a first gear 22, a second gear 23, and a fastener 24.

[0037] Among them:

[0038] The driving shaft 21 is coaxially arranged with the outer wheel 10, and can be rotated around the central axis under the drive of an external power source, such as a servo motor or a stepper motor. In the present embodiment, the driving shaft 21 is preferably made of high-strength alloy steel material, and the surface is hardened to ensure sufficient strength and wear resistance.

[0039] The first gear 22 and the second gear 23 are rotatably sleeved on the driving shaft 21, and the centers of the two gears are both eccentrically arranged at equal distances relative to the rotation center of the driving shaft 21. Specifically, as shown in Figure 2 and Figure 6 , the line connecting the centers of the first gear 22 and the second gear 23 passes through the rotation center of the driving shaft 21, and the first gear 22 and the second gear 23 have equal eccentric distances, which ensures the dynamic balance of the inner wheel assembly 20 during rotation, effectively reducing vibration and noise.

[0040] Simultaneously, the first gear 22 and the second gear 23 together form the first external tooth 25 that meshes with the internal tooth 11. There is a specific difference in the number of teeth between the first external tooth 25 and the internal tooth 11; for example, in this embodiment, the number of teeth on the first external tooth 25 may be three fewer than the number of teeth on the internal tooth 11. Figure 6 As shown, due to the eccentric setting, the first external tooth 25 is roughly elliptical. Its long axis ends are tightly meshed with the internal tooth 11, while its short axis ends are disengaged from the internal tooth 11 or maintain a large gap. When the drive shaft 21 drives the first external tooth 25 to rotate, the outer wheel 10 will generate a small angular displacement corresponding to the difference in the number of teeth through the meshing of the internal tooth 11 and the first external tooth 25, thereby achieving deceleration.

[0041] like Figure 5 and Figure 7 As shown, fastener 24 is mounted on drive shaft 21 to achieve precise control over the positions of the first gear 22 and the second gear 23. Specifically, fastener 24 has a dual function: on the one hand, fastener 24 is used to fix the first gear 22 and the second gear 23 to the drive shaft 21 in the first working state so that they rotate together with the drive shaft 21, at which time the inner gear assembly 20 is working in the normal transmission state; on the other hand, fastener 24 is used to release the first gear 22 and the second gear 23 in the second working state so that the first gear 22 and the second gear 23 can rotate relative to the drive shaft 21. That is, when it is necessary to adjust the backlash, fastener 24 can release the first gear 22 and the second gear 23 so that they can rotate freely around the drive shaft 21, thereby fine-tuning the position of the first external tooth 25 in the circumferential direction of the outer gear 10 to eliminate the backlash when meshing with the inner tooth 11. In this embodiment, the fastener 24 can be implemented in various forms, such as a pin fixing structure or a threaded locking device. That is, the first gear 22 and the second gear 23 can be easily locked or released through simple plugging or unplugging or screwing operations without disassembling the entire reducer, which greatly simplifies the maintenance process.

[0042] In practical applications, when increased backlash, decreased transmission accuracy, or reverse backlash is detected in the reducer after prolonged use, the following steps can be taken: First, loosen the fastener 24 to release the first gear 22 and the second gear 23; second, slightly rotate the first gear 22 and the second gear 23 using a tool to change the relative position angle between the long axis of the first external tooth 25 and the drive shaft 21, so that the tooth surfaces at both ends of the long axis of the first external tooth 25 can more tightly abut against the tooth surfaces of the corresponding teeth on the internal tooth 11; finally, while maintaining this optimal meshing state, re-tighten the fastener 24. This simple adjustment method effectively eliminates backlash caused by gear wear due to long-term operation, maintaining the high precision and stability of the transmission system.

[0043] In another embodiment, as shown in Figure 2 , Figure 3 , Figure 5 , Figure 9 , the third gear 41 and the fourth gear 42 are also included, which are fixedly connected to the drive shaft 21, the centers of the third gear 41 and the fourth gear 42 are eccentrically arranged relative to the rotation center of the drive shaft 21, and the line connecting the centers of the third gear 41 and the fourth gear 42 passes through the rotation center of the drive shaft 21 to ensure balance; at the same time, the third gear 41 and the fourth gear 42 jointly constitute a second external gear meshing with the internal gear 11, and the size of the second external gear is the same as that of the first external gear 25, that is, the number and size of the teeth of the second external gear are completely the same as those of the first external gear 25, ensuring consistency of the transmission characteristics, and the difference between the two is that the third gear 41 and the fourth gear 42 are directly fixed on the drive shaft 21 and cannot rotate relative to the drive shaft 21, but rotate together with the drive shaft 21. In addition, the normal projection of the long axis of the first external gear 25 and the long axis of the second external gear on the axial direction of the drive shaft 21 is arranged in parallel or at a predetermined angle.

[0044] With this structure design, on the one hand, the first external gear 25 and the second external gear jointly act on the internal gear 11 during work to disperse the load, so that the force borne by each gear is reduced, and it can bear greater torque; on the other hand, in the initial state, the normal projection of the long axis of the first external gear 25 and the long axis of the second external gear on the axial direction of the drive shaft 21 is arranged in parallel, when the first gear 22 and the second gear 23 are released by the fastener 24, and they are rotated clockwise to change the relative position angle of the long axis of the first external gear 25 and the drive shaft 21, the outer wheel 10 will rotate clockwise by a corresponding angle in response to this adjustment, and in the counterclockwise direction, the rotation of the outer wheel 10 will be limited by the second external gear, because the tooth surfaces at both ends of the long axis of the second external gear can tightly abut against the counterclockwise tooth surfaces of the corresponding teeth on the internal gear 11. It should be noted that the first external gear 25 rotates a certain angle in the circumferential direction of the drive shaft 21, and this angle of adjustment is i times the backlash angle of the internal gear assembly 20 and the outer wheel 10, where i is the reduction ratio of the reducer. Exemplarily: if the output backlash of the reducer is 0.5 degrees, i = 50, then the first external gear 25 rotates 25 degrees relative to the second external gear in the circumferential direction of the drive shaft 21 to complete the backlash elimination.

[0045] Thus, after the adjustment is completed, the long axis of the first outer tooth 25 and the long axis of the second outer tooth are no longer parallel in the axial direction of the drive shaft 21, but are staggered in the axial direction of the drive shaft 21, that is, the long axis of the first outer tooth 25 and the long axis of the second outer tooth are arranged at a predetermined angle in the orthogonal projection in the axial direction of the drive shaft 21, which ensures that after the tooth gap elimination operation is completed, no matter whether the drive shaft 21 is output in forward rotation or reverse rotation, the first outer tooth 25 formed by the first gear 22 and the second gear 23 and the second outer tooth formed by the third gear 41 and the fourth gear 42 can be closely engaged with the inner tooth 11, completely eliminating the idling stroke of each gear, ensuring that there is no gap in the forward and reverse rotation directions of the first gear 22, the second gear 23, the third gear 41 and the fourth gear 42, achieving zero backlash transmission.

[0046] In a specific embodiment, as shown in Figure 2 、 Figure 3 、 Figure 5 、 Figure 9 The inner wheel assembly 20 also includes a gap adjuster 26, which is sleeved on the drive shaft 21 and can rotate relative to the drive shaft 21. In this embodiment, the gap adjuster 26 is a shaft sleeve structure sleeved on the drive shaft 21, and eccentric cams for mounting the first gear 22 and the second gear 23 are provided on the shaft sleeve structure, and the first gear 22 and the second gear 23 are fixedly connected to the gap adjuster 26 in sequence along the axial direction of the drive shaft 21, that is, on the eccentric cams, so that the first gear 22 and the second gear 23 form an integral structure with the gap adjuster 26; the fastener 24 is arranged on the gap adjuster 26 and is used to fix the first gear 22 and the second gear 23 to the drive shaft 21 through the gap adjuster 26 in the first working state, or release the first gear 22 and the second gear 23 in the second working state. When the fastener 24 locks the gap adjuster 26 on the drive shaft 21, the first gear 22 and the second gear 23 are also fixed at a specific position and rotate together with the drive shaft 21; when it is necessary to adjust the tooth gap, the fastener 24 is loosened, and the gap adjuster 26 can rotate freely relative to the drive shaft 21, and at this time the engagement position of the first gear 22 and the second gear 23 with the inner tooth 11 can be accurately adjusted. In this way, the position of the two gears can be adjusted at the same time by controlling the gap adjuster 26 during adjustment, and the adjustment operation is simple.

[0047] It can be understood that the first gear 22 and the second gear 23 and the third gear 41 and the fourth gear 42 can be fixed on the drive shaft 21 in the form of an eccentric shaft sleeve, and in other examples, they can also be fixed by internal expansion or automatic adjustment by strong springs, and the fundamental purpose is to adjust the relative angle of the first outer tooth 25 relative to the second outer tooth after adjustment and fixing, so that the first gear 22 and the second gear 23 and the third gear 41 and the fourth gear 42 rotate together.

[0048] In some embodiments, as shown in Figure 2 , Figure 3 , Figure 5 , Figure 9 the drive shaft 21 has an exposed part 211 extending out of the gap adjuster 26, the fastener 24 is threadedly connected with the exposed part 211 and has a pressing sleeve 241 extending towards the gap adjuster 26; the inner diameter of the pressing sleeve 241 unidirectionally increases towards the side away from the fastener 24 in the axial direction of the drive shaft 21, and forms a tapered pressing space 242 with the outer circumferential surface of the drive shaft 21; one end of the gap adjuster 26 at least partially extends into the tapered pressing space 242; when the fastener 24 is tightened, the pressing sleeve 241 applies radial pressure to the gap adjuster 26, so that the gap adjuster 26 is connected and fixed with the drive shaft 21. In actual operation, when it is necessary to adjust the gear backlash, the radial pressure of the pressing sleeve 241 on the gap adjuster 26 can be released by loosening the fastener 24, such as a locking nut, so that the gap adjuster 26 can freely rotate relative to the drive shaft 21 to adjust the gear backlash; after the adjustment is completed, the fastener 24 is tightened again to firmly fix the gap adjuster 26 on the drive shaft 21, and the normal working state of the speed reducer is restored. This tapered pressing sleeve fastening structure makes the gear backlash adjustment operation more convenient and reliable, and can maintain stable connection performance for a long time.

[0049] In some embodiments, as shown in Figure 2 , Figure 3 , Figure 7 the end of the gap adjuster 26 extending into the tapered pressing space 242 is provided with a guide inclined surface 261 adapted to the inner wall of the pressing sleeve 241, which can well fit the inner wall of the pressing sleeve 241 and provide assembly guidance during assembly. A plurality of deformation notches 262 extending in the axial direction of the gap adjuster 26 are formed on the guide inclined surface 261, which enables the end of the gap adjuster 26 to elastically deform when subjected to radial pressure. In this embodiment, it is preferred to provide three or four deformation notches 262, which are evenly distributed in the circumferential direction, so as to reduce the local stiffness of the end of the gap adjuster 26 and make it a weak area of elastic deformation. When the fastener 24 is tightened and the pressing sleeve 241 applies radial pressure to the gap adjuster 26, the end of the gap adjuster 26 elastically deforms under the action of the radial pressure due to the presence of the deformation notches 262, which enables the end of the gap adjuster 26 to better fit the outer circumferential surface of the drive shaft 21, increases the actual contact area, and realizes more uniform radial pressure distribution, thereby significantly improving the clamping effect and connection reliability.

[0050] In some embodiments, as shown in Figure 3 , Figure 7As shown, the outer surface of the fastener 24 is provided with a first slot structure, which can be in the form of an outer hexagon provided on the outer surface of the fastener 24, or other applicable tool interface form for external tools to be screwed. The end of the deformation gap 262 is provided with a second slot structure 263, which in this embodiment is specifically a through hole provided at the axial end of the deformation gap 262, which can be matched with a tool such as a pin wrench or a pin wrench to realize fine adjustment of the gap adjuster 26 relative to the drive shaft 21.

[0051] In some embodiments, as Figure 2 、 Figure 6 、 Figure 9 As shown, a synchronization rod 28 is further included, the overlapping part of the orthographic projection of the first gear 22 and the second gear 23 on the drive shaft 21 is provided with a through hole 27, and the synchronization rod 28 passes through the through hole 27, so that the first gear 22 and the second gear 23 can be synchronously rotated. In specific implementation, the number of through holes 27 can be adjusted according to the size of the gear, and in this embodiment, six circumferentially uniformly distributed through holes 27 are preferably provided, and at the same time, the synchronization rod 28 provides a synchronous constraint force for the first gear 22 and the second gear 23, thereby improving the overall strength and rigidity. In other examples, similarly, the third gear 41 and the fourth gear 42 are also provided with through holes 27 corresponding to those on the first gear 22 and the second gear 23, and when the first gear 22, the second gear 23, the third gear 41 and the fourth gear 42 are assembled along the axial direction of the drive shaft 21, the through holes 27 on each gear overlap with each other in the axial direction of the drive shaft 21, and together form a channel for the synchronization rod 28 to be inserted into, and in this embodiment, the inner diameter of the channel is set to be slightly larger than the diameter of the synchronization rod 28, so as to allow the first gear 22 and the second gear 23 and the gap adjuster 26 to have a certain positional change relative to the third gear 41 and the fourth gear 42 fixed on the drive shaft 21 when the gap adjuster 26 is used to adjust the tooth gap, i.e., to allow the first external tooth 25 and the second external tooth to have a relative angular displacement within a certain angle range to complete the gap elimination, while avoiding the long axis of the first external tooth 25 and the long axis of the second external tooth being misaligned by too large an angle in the axial direction of the drive shaft 21.

[0052] In some embodiments, as Figure 2 、 Figure 6 、 Figure 9The first bearing 31, the first base 32 and the second base 33 are also shown, one end of the drive shaft 21 passes through the first base 32 and is connected and fixed by the inner ring of the first bearing 31 through the gap adjuster 26, the outer ring of the first bearing 31 is connected and fixed on the second base 33, and the first gear 22 and the second gear 23 are located between the first base 32 and the second base 33; the synchronization rod 28 is provided with a plurality of and has opposite first and second ends, wherein the synchronization rod 28 located on the circumferential rear side of the drive shaft 21 is integrally formed with the first base 32 through its first end, and the synchronization rod 28 located on the circumferential front side of the drive shaft 21 is integrally formed with the second base 33 through its second end; the first base 32 is provided with a first insertion hole 321 matched with the first end of the synchronization rod 28 on the second base 33, and the second base 33 is provided with a second insertion hole 331 matched with the second end of the synchronization rod 28 on the first base 32. Specifically, six synchronization rods 28 are provided, a plurality of first insertion holes 321 are provided on the first base 32, and a plurality of second insertion holes 331 are provided on the second base 33, and the positions and sizes of the insertion holes are matched with the shapes and sizes of the two ends of the synchronization rod 28. In the assembly process, due to the guiding effect of the first insertion hole 321 and the second insertion hole 331, the two ends of the synchronization rod 28 can be accurately inserted into the corresponding insertion holes, thereby forming a stable wheel frame, which is good in rigidity, compact in structure and also helps to save installation space, and is beneficial to the miniaturization of the whole speed reducer.

[0053] It should be noted that in the present embodiment, one of the outer wheel 10 or the wheel frame formed by the synchronization rods 28, the first base 32 and the second base 33 is taken as the fixed end (connected to the external support structure or base) of the speed reducer, and the other is taken as the output end (connected to the external load or actuator). This means that the output end and the fixed end of the speed reducer can be the outer wheel and the wheel group frame which are interchangeable.

[0054] In a preferred embodiment, the reducer is fixedly connected to the external support structure through the wheel carrier: in this configuration, the wheel carrier is fixed as the support base of the inner wheel assembly 20 and the outer wheel 10, the drive shaft 21 is rotatably mounted on the wheel carrier and configured to receive power input from an external driving device (such as a motor) to realize rotation relative to the fixed wheel carrier; at this time, the outer wheel 10 serves as the output end of the reducer for connecting external loads or other transmission mechanisms. In another embodiment, the reducer can also be achieved by fixing the outer wheel 10 to the external support structure: in this configuration, the outer wheel 10 acts as the fixed end of the reducer, while the drive shaft 21 continues to act as the input end, receiving power from an external driving device to realize rotation relative to the fixed outer wheel 10; at this time, the wheel carrier becomes the output end of the reducer for connecting external loads or other components that need to be driven, i.e. through the meshing transmission of the inner wheel assembly and the fixed outer wheel, the input rotation of the drive shaft will cause the wheel carrier to produce a decelerated rotation relative to the outer wheel, thereby achieving power output. This configuration of interchanging the fixed end and the output end greatly improves the flexibility and application range of the design of the reducer, making it able to adapt to a variety of different installation and transmission requirements.

[0055] In some embodiments, as shown in Figure 2 、 Figure 9 the second end of the synchronization rod 28 on the first base 32 is provided with a threaded hole that penetrates the second base 33, and the second base 33 is threadedly connected to the threaded hole of the synchronization rod 28 on the first base 32 through a fastening screw. Threaded connection can provide sufficient connection strength to ensure stable connection between the first base 32 and the second base 33, and it is not easy to loosen even in the case of impact or vibration of the entire reducer.

[0056] In some embodiments, as shown in Figure 2 、 Figure 5 、 Figure 9 the first base 32 and the second base 33 are both provided with a second bearing 35 coaxial with the outer wheel 10, and the outer ring of the second bearing 35 is fixed on the inner circumferential surface of the outer wheel 10. In this embodiment, the outer wheel 10 constitutes the output end, on which a flange or other connecting mechanism can be provided for easy connection with other components, such as the joints of a robot, the worktable of a machine tool, etc. When the reducer is working, the first outer tooth 25 cooperates with the second outer tooth to drive the outer wheel 10 to rotate, and the outer wheel 10 transmits the decelerated rotary motion to the external load stably and accurately through the support of the second bearing 90.

[0057] The gap eliminator designed in the application adopts an adjustment gap device which can be selectively fixed or rotated relative to the driving shaft, and a first gear and a second gear are eccentrically arranged on the adjustment gap device, so that the user only needs to release the fixed state of the adjustment gap device when necessary, and the meshing gap of the first gear and the second gear relative to the inner teeth of the outer wheel can be accurately controlled by slightly rotating the adjustment gap device, thereby effectively compensating for the tooth side gap caused by manufacturing tolerances, assembly errors or long-term running wear; at the same time, by directly using the first gear and the second gear as the external tooth structure meshing with the inner teeth on the inner circumferential surface of the outer wheel, the intermediate link in the traditional multi-stage gear transmission chain is omitted, and the transmission path is more direct, which helps to realize a highly compact overall structure and lightweight design.

[0058] In the description of the present application, it should be noted that the terms "vertical", "upper", "lower", "horizontal" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0059] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0060] Finally, it should be pointed out that: the above only describes the preferred embodiments of the present application, and is not intended to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A backlash elimination reducer comprising an outer wheel and an inner wheel assembly arranged coaxially, characterized in that, The inner wheel assembly comprises: a drive shaft, a first gear and a second gear rotatably sleeved on the drive shaft, the centers of the first gear and the second gear being eccentrically arranged at equal distances from the rotation center of the drive shaft, and the line connecting the centers of the first gear and the second gear passing through the rotation center of the drive shaft; a fastener for fixing the first gear and the second gear to the drive shaft to rotate together in a first working state, or releasing the first gear and the second gear to enable the first gear and the second gear to rotate relative to the drive shaft in a second working state; wherein the inner periphery of the outer wheel is provided with internal teeth, the first gear and the second gear jointly constitute first external teeth meshing with the internal teeth, and the first external teeth and the internal teeth have a difference in the number of teeth.

2. The lost motion reducer of claim 1, wherein Further comprising: a third gear and a fourth gear fixedly connected to the drive shaft, the centers of the third gear and the fourth gear being eccentrically arranged at equal distances from the rotation center of the drive shaft, and the line connecting the centers of the third gear and the fourth gear passing through the rotation center of the drive shaft; wherein the third gear and the fourth gear jointly constitute second external teeth meshing with the internal teeth, and the second external teeth and the first external teeth are of the same size; the long axis of the first external teeth and the long axis of the second external teeth are arranged in parallel or at a predetermined angle in the normal projection of the drive shaft in the axial direction.

3. A lost motion reducer according to claim 1 or 2, characterized in that The inner wheel assembly further comprises a gap adjuster, the gap adjuster being sleeved on the drive shaft and capable of rotating relative to the drive shaft; the first gear and the second gear are fixedly connected to the gap adjuster in sequence in the axial direction of the drive shaft; the fastener is arranged on the gap adjuster and is used to fix the first gear and the second gear to the drive shaft in the first working state or release the first gear and the second gear in the second working state through the gap adjuster.

4. The lost motion reducer of claim 3, wherein The drive shaft has an exposed part protruding out of the gap adjuster, the fastener is threadedly connected with the exposed part and has a pressing sleeve extending towards the gap adjuster; the inner diameter of the pressing sleeve unidirectionally increases towards the side away from the fastener in the axial direction of the drive shaft, and forms a tapered pressing space with the outer periphery of the drive shaft; one end of the gap adjuster at least partially extends into the tapered pressing space; when the fastener is screwed, the pressing sleeve exerts radial pressure on the gap adjuster, so that the gap adjuster is fixedly connected with the drive shaft.

5. The lost motion decelerator of claim 4, wherein, The end of the gap adjuster extending into the tapered pressing space is provided with a guide slope matched with the inner wall of the pressing sleeve, a plurality of deformation notches extending in the axial direction of the gap adjuster are formed on the guide slope, and the deformation notches enable the end of the gap adjuster to elastically deform when subjected to radial pressure.

6. The lost motion reducer of claim 5, wherein The outer surface of the fastener is provided with a first groove structure, and the end of the deformation notch is provided with a second groove structure, both the first groove structure and the second groove structure being used for being screwed by an external tool.

7. The lost motion decelerator of claim 3, wherein The synchronous rod is further provided with a through hole in the overlapping part of the axial projection of the first gear and the second gear, and the synchronous rod passes through the through hole, so that the first gear and the second gear can rotate synchronously.

8. The lost motion decelerator of claim 7, wherein, The first bearing, the first base and the second base opposite to the first base are further included, one end of the driving shaft passes through the first base and is connected and fixed in the inner ring of the first bearing through the pitch adjuster, the outer ring of the first bearing is connected and fixed on the second base, and the first gear and the second gear are located between the first base and the second base; the synchronous rod is provided with a plurality of first ends and second ends opposite to each other, the synchronous rod located on the circumferential back side of the driving shaft is integrally formed with the first base through the first end, and the synchronous rod located on the circumferential front side of the driving shaft is integrally formed with the second base through the second end; the first base is provided with a first insertion hole matched with the first end of the synchronous rod on the second base, and the second base is provided with a second insertion hole matched with the second end of the synchronous rod on the first base.

9. The lost motion decelerator of claim 8, wherein, The second end of the synchronous rod on the first base is provided with a screw hole penetrating the second base, and the second base is threadedly connected with the screw hole of the synchronous rod on the first base through a fastening screw.

10. The lost motion decelerator of claim 8, wherein, The first base and the second base are both provided with a second bearing coaxial with the outer wheel, and the outer ring of the second bearing is fixed on the inner circumferential surface of the outer wheel.

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