A self-clearing structure RV reducer

Abstract

The present invention provides a self-clearing structure RV reducer, which relates to the technical field of reducers, including a pin gear housing, an output shaft, an output end cover, an input shaft, and an eccentric shaft. A cycloid wheel is provided on each eccentric shaft cam, and a plurality of needle rollers meshing with the cycloid wheel spur gears are provided in a circumferential array on the inner wall of the pin gear housing. A planetary wheel is installed at one end of the eccentric shaft close to the output shaft, and an input gear meshing with the planetary wheel spur gears is provided at the end of the input shaft, and an input shaft gear meshing with the planetary wheel spur gears is provided on the outer wall of the end of the input shaft; each cycloid wheel includes a first cycloid and a second cycloid, and a cycloid elastic clearing structure driving the circumferential rotation dislocation thereof is provided between the corresponding first cycloid and the second cycloid, and an input elastic clearing structure driving the circumferential rotation dislocation thereof is provided between the input gear and the end of the input shaft. The present invention can eliminate the tooth clearance increased due to wear between the cycloid wheel and the needle roller, and between the input gear and the planetary wheel, so that the reducer can still maintain high precision and high rigidity after a certain amount of wear occurs.

Description

Technical Field

[0001] The invention relates to the technical field of reducers, and in particular to an RV reducer with a self-backlash eliminating structure. Background Art

[0002] There are multiple friction pairs inside the reducer, such as the friction between the rolling element and the inner and outer rings of the bearing, the friction between the inner teeth of the pinion housing and the outer teeth of the cycloid wheel during meshing transmission, etc. After the reducer has been running for a long time, even if it is fully lubricated, some wear and tear will inevitably occur between the components. When the wear value reaches a certain amount, the gear gap of the reducer will increase, especially for the RV reducer used in the robot joint. If the gear gap increases, it will cause the robot origin to drift, thereby reducing the trajectory accuracy of the robot. Summary of the invention

[0003] The purpose of the present invention is to provide a self-clearing structure RV reducer, which can eliminate the tooth clearance that increases due to certain wear of the reducer after long-term operation, so that the reducer can still maintain high precision and high rigidity after certain wear.

[0004] The above technical objectives of the present invention are achieved through the following technical solutions:

[0005] A self-clearing RV reducer comprises a pinion housing, an output shaft, an output end cover, an input shaft, and at least two eccentric shafts arranged in a circumferential array, wherein two cams of the eccentric shaft are respectively provided with cycloid wheels, a plurality of semicircular grooves are arranged in a circumferential array on the inner wall of the pinion housing, a needle roller matching therewith is installed in the semicircular groove, and the outer wall of the cycloid wheel is meshed with the needle roller spur teeth; a planetary gear is installed at one end of the eccentric shaft close to the output shaft, an input gear meshed with the planetary gear spur teeth is arranged at the end of the input shaft, and the outer wall of the end of the input shaft is provided with a gear integrally formed with the planetary gear and meshed with the planetary gear spur teeth. An input shaft gear meshing with the planetary gear spur teeth; the two cycloid wheels are respectively mounted on the cam of the eccentric shaft through needle rollers and retainer bearings, each of the cycloid wheels comprises a first cycloid and a second cycloid, and a cycloid elastic anti-backlash structure is provided between the first cycloid and the second cycloid, the cycloid elastic anti-backlash structure drives the first cycloid and the second cycloid to rotate and misalign along their circumferential direction; an input elastic anti-backlash structure is provided between the input gear and the end of the input shaft, the input elastic anti-backlash structure drives the input gear to rotate and misalign relative to the end of the input shaft along its circumferential direction.

[0006] By adopting the above technical scheme, the two cycloidal wheels on each eccentric shaft are in straight tooth meshing with the needle roller. When wear occurs between the cycloidal wheel and the eccentric shaft and between the needle roller and the retaining frame, a gap will be generated between the cycloidal wheel, the needle roller and the eccentric shaft. In the present invention, each cycloidal wheel is configured as a split type, including a first cycloidal line and a second cycloidal line. The first cycloidal line and the second cycloidal line are driven to rotate and displace by a certain amount along their circumferential direction through a cycloidal elastic gap-eliminating structure. After the first cycloidal line and the second cycloidal line are displaced, the gap between them and the cam on the eccentric shaft is eliminated. After the two clamp the eccentric shaft cam, each has one side offset outward to mesh with the needle roller, thereby eliminating the wear gap between the cycloidal wheel as a whole and the needle roller. Similarly, the input gear and the input shaft gear are equivalent to changing the original integral body meshing with the planetary gear into a split type. Under normal circumstances, the input gear and the input shaft gear are both meshing with the planetary gear. When wear occurs between the input gear, the input shaft gear and the planetary gear and wear clearance is generated, the input elastic anti-backlash structure drives the input gear to rotate and offset a certain amount along its circumferential direction compared to the input shaft, so that the input gear approaches the planetary gear and meshes closely with it, eliminating the wear clearance between the input gear and the planetary gear, and eliminating the reverse clearance between the planetary gear and the input shaft gear during the rotation of the planetary gear.

[0007] The present invention provides an input elastic clearance eliminating structure to elastically eliminate the wear clearance between the input gear on the input side and the planetary gear, and provides a cycloid elastic clearance eliminating structure to elastically eliminate the wear clearance between the cycloid wheel and the needle roller, thereby realizing self-elimination of the wear clearance generated after the reducer has been running for a long time, improving the meshing accuracy between the cycloid wheel and the needle roller, the input gear and the planetary gear, and improving the service life of the reducer, reducing the meshing error caused by processing and assembly, and improving the transmission accuracy. The improvement of the meshing condition greatly reduces the vibration of the reducer during operation, so the present invention has the characteristics of self-elimination of clearance, long service life, high precision, low vibration, and the like.

[0008] Furthermore, the cycloid elastic gap-eliminating structure includes a plurality of first gap-eliminating semi-arc grooves arranged in a circumferential array on the side of the first cycloid close to the second cycloid, and a plurality of second gap-eliminating semi-arc grooves corresponding to the first gap-eliminating semi-arc grooves are arranged in a circumferential array on the side of the second cycloid close to the first cycloid; the ends of the first gap-eliminating semi-arc groove and the second gap-eliminating semi-arc groove corresponding to each other are staggered, the overlapping part of the first gap-eliminating semi-arc groove and the second gap-eliminating semi-arc groove constitutes a circular hole and a cycloid gap-eliminating spring is arranged in the circular hole, one end of the cycloid gap-eliminating spring is abutted against the end of the first gap-eliminating semi-arc groove, and the other end is abutted against the end of the second gap-eliminating semi-arc groove.

[0009] By adopting the above technical scheme, the first clearance-eliminating semicircular groove and the second clearance-eliminating semicircular groove are staggered, and the projection parts on the fitting surfaces thereof intersect, and the intersecting parts are combined to form a circular hole, and the cycloid clearance-eliminating spring is arranged in the circular hole, that is, the cycloid clearance-eliminating spring is located in both the first clearance-eliminating semicircular arc groove and the second clearance-eliminating semicircular arc groove, and its two ends are respectively abutted against the two ends of the intersecting part of the projection of the first clearance-eliminating semicircular arc groove and the second clearance-eliminating semicircular arc groove, so that the two ends of the cycloid clearance-eliminating spring respectively apply force to the first cycloid and the second cycloid through the ends of the first clearance-eliminating semicircular arc groove and the second clearance-eliminating semicircular arc groove, so that the relative first cycloid and the second cycloid can rotate relative to each other along their circumferential direction. When wear and tear occurs between the cycloid wheel and the eccentric shaft and between the needle roller and the cage bearing, and a gap is generated, the first cycloid and the second cycloid will rotate relative to each other, eliminating the gap between the cycloid wheel and the eccentric shaft and clamping the eccentric shaft, and one side of the first cycloid and the second cycloid will deviate outward to engage with the needle roller, thereby eliminating the wear gap between the cycloid wheel and the needle roller and ensuring the meshing accuracy between the cycloid wheel and the needle roller.

[0010] Furthermore, the circumferential arrays on the first cycloid and the second cycloid are provided with a plurality of eccentric shaft holes corresponding to the eccentric shafts respectively, and the number and positions of the first anti-backlash semi-circular arc grooves and the second anti-backlash semi-circular arc grooves correspond one-to-one to the eccentric shaft holes.

[0011] By adopting the above technical scheme, the number and position of the first anti-backlash semicircular arc groove and the second anti-backlash semicircular arc groove correspond one by one to the eccentric shaft hole, so that the cycloid elastic anti-backlash structure can evenly drive the first cycloid and the second cycloid to rotate and misalign, accurately eliminate the wear gap between the cycloid wheel and multiple eccentric shafts and several roller needles, and ensure the wear gap elimination effect. The structure is simple and the effect is obvious.

[0012] Furthermore, the cycloid anti-backlash spring is pre-compressed by the first anti-backlash semicircular arc groove and the second anti-backlash semicircular arc groove, providing relative rotation force for the first cycloid and the second cycloid. When wear occurs between the cycloid wheel, the eccentric shaft, the needle roller and the retainer bearing, the cycloid anti-backlash spring causes the first cycloid and the second cycloid to rotate out of place, eliminating the wear gap between the cycloid wheel, the needle roller and the eccentric shaft.

[0013] By adopting the above technical scheme, the cycloid anti-backlash spring is installed in a pair of first anti-backlash semicircular arc grooves and a second anti-backlash semicircular arc groove and is in a certain compression state, so that after a wear gap is generated between the cycloid wheel and the eccentric shaft and between the needle roller and the retainer bearing, the elastic force of the cycloid anti-backlash spring drives the first cycloid and the second cycloid to rotate relative to each other by a certain amount, thereby eliminating the wear gap between the cycloid wheel and the eccentric shaft and the needle roller, ensuring the meshing accuracy of the cycloid wheel and the needle roller, and allowing the reducer to maintain high precision and high rigidity after a certain wear occurs.

[0014] Furthermore, the input elastic clearance eliminating structure includes a plurality of third clearance eliminating semi-circular arc grooves arranged in a circumferential array on the side of the input gear close to the input shaft, and a plurality of fourth clearance eliminating semi-circular arc grooves corresponding to the third clearance eliminating semi-circular arc grooves are arranged in a circumferential array at the end of the input shaft; the third clearance eliminating semi-circular arc grooves and the fourth clearance eliminating semi-circular arc groove ends corresponding to each other are staggered, the overlapping parts of the third clearance eliminating semi-circular arc groove and the fourth clearance eliminating semi-circular arc groove constitute a circular hole and an input clearance eliminating spring is arranged in the circular hole, one end of the input clearance eliminating spring abuts against the end of the third clearance eliminating semi-circular arc groove, and the other end abuts against the end of the fourth clearance eliminating semi-circular arc groove.

[0015] By adopting the above technical solution, the third clearance-eliminating semicircular arc groove and the fourth clearance-eliminating semicircular arc groove are staggered, and the projections of the two on the plane where the input shaft and the input gear fit together intersect to form a circular hole, and the input clearance-eliminating spring is arranged in the circular hole, that is, the input clearance-eliminating spring is located in both the third clearance-eliminating semicircular arc groove and the fourth clearance-eliminating semicircular arc groove, and its two ends are respectively abutted against the two ends of the intersection of the projections of the third clearance-eliminating semicircular arc groove and the fourth clearance-eliminating semicircular arc groove, so that the two ends of the input clearance-eliminating spring respectively apply force to the input gear and the input shaft through the ends of the third clearance-eliminating semicircular arc groove and the fourth clearance-eliminating semicircular arc groove, so that the input gear can rotate relative to the input shaft along its circumferential direction. When the input gear, the input shaft gear and the planetary gear are worn, the input gear can rotate relative to the input shaft by a certain amount, eliminating the gap between the input gear and the planetary gear, so that the input gear and the planetary gear are tightly meshed, and the meshing accuracy between the input gear and the planetary gear is ensured.

[0016] Furthermore, the input backlash eliminating spring is pre-compressed by the third backlash eliminating semicircular arc groove and the fourth backlash eliminating semicircular arc groove to provide relative rotation force for the input gear and the input shaft. When wear occurs between the input gear, the input shaft gear and the planetary gear, the input backlash eliminating spring causes the input gear to rotate out of position relative to the input shaft to eliminate the wear gap between the input gear and the planetary gear, and eliminates the reverse gap between the planetary gear and the input shaft gear during the rotation of the planetary gear.

[0017] By adopting the above technical solution, the input backlash eliminating spring is installed in a pair of third backlash eliminating semicircular arc grooves and a fourth backlash eliminating semicircular arc groove and is in a certain compression state, so that after the wear gap is generated between the input gear, the input shaft gear and the planetary gear, the elastic force of the input backlash eliminating spring drives the input gear to rotate relative to the input shaft to be staggered by a certain amount, thereby eliminating the wear gap between the input gear and the planetary gear, ensuring the meshing accuracy between the input gear and the planetary gear, and eliminating the reverse gap between the planetary gear and the input shaft gear during the rotation of the planetary gear, so that the reducer can still maintain high precision and high rigidity after a certain wear occurs.

[0018] Furthermore, a cap is provided on a side of the input gear away from the input shaft, and a rotation gap is provided between the cap and the input gear.

[0019] By adopting the above technical solution, the input gear is limited by the retaining cap to prevent the input gear from being separated from the input shaft, thereby ensuring the stability of the input anti-backlash spring installation and the elastic anti-backlash working effect. A rotation gap is provided between the retaining cap and the input gear to prevent the retaining cap from locking the input gear and affecting the rotation of the input gear. The structure is simple and the effect is obvious.

[0020] Furthermore, an installation bearing is provided between the outer circle of the output shaft and the outer circle of the output end cover and the inner circle of the pin gear housing, and the installation bearing is one of a tapered roller bearing, a deep groove ball bearing, and an angular contact ball bearing; a skeleton sealing ring is provided between the output shaft and the pin gear housing, and the skeleton sealing ring is located on the side where the two installation bearings are away from each other.

[0021] By adopting the above technical solution, the output shaft and the output end cover are installed on the pinion housing through the installation bearing, and the assembly composed of the output shaft and the output end cover can make relative rotational motion with the pinion housing, thereby ensuring the stability of the installation and operation of the output shaft and the output end cover. The skeleton sealing ring is installed between the output shaft and the pinion housing to achieve sealing between the two and improve the sealing performance of the reducer.

[0022] Furthermore, the two ends of the eccentric shaft are respectively positioned and rotatably mounted on the output shaft and the output end cover through first tapered roller bearings, and a cushion block is provided on the side of the first tapered roller bearing close to the cam on the eccentric shaft, and a first axial retaining ring is provided on the side of the two first tapered roller bearings away from each other.

[0023] By adopting the above technical solution, two first tapered roller bearings are used to realize the installation between the eccentric shaft and the output shaft and the output end cover, thereby ensuring the stability of the eccentric shaft. Among them, a cushion block is provided to reduce the wear between the first tapered roller bearing and the eccentric shaft cam, thereby avoiding affecting the normal operation of the cycloid wheel and improving the service life. In addition, the first axial retaining ring axially limits the eccentric shaft to avoid the eccentric shaft driving the cycloid wheel to move along its axial direction, thereby affecting the elastic clearance elimination effect of the cycloid elastic clearance elimination structure on the cycloid wheel and the needle roller.

[0024] Furthermore, the planetary gear is mounted on one end of the eccentric shaft close to the output shaft through a spline, and second axial retaining rings are provided on both sides of the planetary gear.

[0025] By adopting the above technical solution, the second axial retaining rings on both sides of the planetary gear limit the axial position of the planetary gear to prevent the planetary gear from moving axially along the cycloid gear, thereby affecting the elastic clearance eliminating effect of the input elastic clearance eliminating structure on the planetary gear and the input gear. The structure is simple and the effect is obvious.

[0026] In summary, the present invention has the following beneficial effects:

[0027] 1. The present invention provides a cycloid wheel as a split type including a first cycloid and a second cycloid, and provides a cycloid elastic clearance-eliminating structure between the first cycloid and the second cycloid, thereby eliminating the wear clearance between the cycloid wheel and the eccentric shaft and between the needle roller and the retaining frame, thereby ensuring close meshing between the cycloid wheel and the needle roller; by providing an input shaft gear on the outer wall of the input shaft, providing an input gear at the end, and providing an input elastic clearance-eliminating structure between the input shaft and the input gear, thereby eliminating the wear clearance between the input gear and the planetary gear, thereby ensuring close meshing between the input gear and the planetary gear; the cycloid elastic clearance-eliminating structure and the input elastic clearance-eliminating structure can eliminate the wear clearance generated by the reducer due to long-term operation, so that the reducer can still maintain high precision and high rigidity after a certain amount of wear occurs;

[0028] 2. After long-term use, the reducer will inevitably wear out, and the wear will cause gaps between mechanical parts. The cycloid elastic gap-eliminating structure and the input elastic gap-eliminating structure in the present invention can eliminate the meshing gap caused by wear, thereby extending the service life of the reducer;

[0029] 3. The transmission accuracy of the reducer depends largely on the dynamic meshing condition of the gears. There are many factors in the processing and assembly that cause the dynamic meshing condition of the gears to fail to reach the theoretical state. The cycloid elastic anti-backlash structure and the input elastic anti-backlash structure in the present invention have elastic anti-backlash capabilities, so the meshing error caused by factors such as processing and assembly can be reduced, and the transmission accuracy of the reducer can be improved;

[0030] 4. A major reason for the vibration of the reducer in motion is due to the inconsistent transmission state of the reducer. The cycloid elastic anti-backlash structure and the input elastic anti-backlash structure in the present invention improve the meshing state between the cycloid wheel and the needle roller, and between the planetary wheel and the input gear, which can greatly reduce the vibration of the reducer during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of a self-clearing RV reducer;

[0032] Figure 2 It is a longitudinal cross-sectional view of the cycloid wheel in the RV reducer with self-backlash elimination structure;

[0033] Figure 3 It is a transverse cross-sectional diagram of the cycloid wheel in the RV reducer with self-backlash elimination structure;

[0034] Figure 4 It is a schematic diagram of the structure in which the cycloid wheel in the RV reducer with self-clearing structure has no wear clearance;

[0035] Figure 5It is a schematic diagram of the structure of the cycloid wheel in the RV reducer with a self-clearing structure when the cycloid elastic clearance-eliminating structure works to eliminate the wear clearance;

[0036] Figure 6 It is a structural diagram of the input shaft stage input gear in a self-backlash-eliminating RV reducer;

[0037] Figure 7 It is a schematic diagram of the structure in which the input gear of the RV reducer with self-clearing structure has no wear clearance;

[0038] Figure 8 It is a structural diagram of the input gear and the input shaft when the input elastic backlash-eliminating structure in the self-backlash-eliminating RV reducer works to eliminate the wear gap.

[0039] In the figure, 1, pin gear housing; 2, needle roller; 3, output shaft; 4, output end cover; 5, mounting bearing; 6, skeleton sealing ring; 7, input shaft; 8, input gear; 9, input shaft gear; 10, input elastic backlash elimination structure; 11, third backlash elimination semicircular arc groove; 12, fourth backlash elimination semicircular arc groove; 13, input backlash elimination spring; 14, cap; 15, rotational gap; 16, eccentric shaft; 17, eccentric shaft hole; 18, first tapered roller bearing; 19, cushion block; 20, first axial retaining ring; 21, planetary gear; 22, second axial retaining ring; 23, needle roller and cage bearing; 24, cycloid wheel; 25, first cycloid; 26, second cycloid; 27, cycloid elastic backlash elimination structure; 28, first backlash elimination semicircular arc groove; 29, second backlash elimination semicircular arc groove; 30, cycloid backlash elimination spring. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] A self-clearing structure RV reducer, such as Figure 1 As shown, it includes a needle gear housing 1, an output shaft 3, an output end cover 4, an input shaft 7, two or three (three in this embodiment) eccentric shafts 16 arranged in a circumferential array, the output shaft 3 and the output end cover 4 are fixed and assembled into a coaxial assembly with the needle gear housing 1 by screws and threaded pins, and a mounting bearing 5 is arranged between the outer circle of the output shaft 3 and the outer circle of the output end cover 4 and the inner circle of the needle gear housing 1, so that the assembly composed of the output shaft 3 and the output end cover 4 can rotate relative to the needle gear housing 1. Among them, the mounting bearing 5 is one of a tapered roller bearing, a deep groove ball bearing, and an angular contact ball bearing. In this embodiment, the mounting bearing 5 is a deep groove ball bearing. In addition, a skeleton sealing ring 6 is arranged between the output shaft 3 and the needle gear housing 1, and the skeleton sealing ring 6 is located on the side of the skeleton bearing close to it away from the output end cover 4, so as to achieve sealing between the output shaft 3 and the needle gear housing 1.

[0042] like Figure 1 As shown, both ends of each eccentric shaft 16 are respectively positioned and rotatably mounted on the output shaft 3 and the output end cover 4 through the first tapered roller bearings 18, so that the eccentric shaft 16 can rotate relative to the assembly formed by the output shaft 3 and the output end cover 4. A cushion block 19 is provided on the side of the two first tapered roller bearings 18 on each eccentric shaft 16 close to the cam on the eccentric shaft 16, and a first axial retaining ring 20 is provided on the side of the two first tapered roller bearings 18 away from each other. The cushion block 19 is used to reduce the wear between the first tapered roller bearings 18 and the cam of the eccentric shaft 16, avoid affecting the normal operation of the cycloidal wheel 24, and increase the service life. At the same time, the first axial retaining ring 20 is used to limit the eccentric shaft 16 in the axial direction to prevent the eccentric shaft 16 from driving the cycloidal wheel 24 to move along its axial direction.

[0043] like Figure 1 As shown, cycloid wheels 24 are respectively installed on the two cams of the eccentric shaft 16, and a plurality of eccentric shaft holes 17 cooperating with the cams on the eccentric shaft 16 are arranged in a circumferential array on the two cycloid wheels 24, and a plurality of eccentric shafts 16 are respectively installed in the corresponding eccentric shaft holes 17, and needle rollers and cage bearings 23 are arranged between the outer wall of the cam of the eccentric shaft 16 and the inner wall of the eccentric shaft hole 17 on the cycloid wheel 24, and the cycloid wheel 24 and the cam on the eccentric shaft 16 are installed by the needle rollers and cage bearings 23. A plurality of semicircular grooves are arranged in a circumferential array on the inner wall of the pin gear housing 1, and needle rollers 2 cooperating therewith are assembled in the semicircular grooves, and the outer teeth on the outer wall of the cycloid wheel 24 and the needle rollers 2 are in spur meshing.

[0044] like Figure 1 As shown, after the reducer is used for a long time, wear will inevitably occur between the cycloid wheel 24 and the eccentric shaft 16 and between the needle roller and the cage bearing 23. The gap caused by the wear will cause the meshing between the outer teeth of the cycloid wheel 24 and the needle roller 2 to be not tight enough, affecting the meshing transmission between the cycloid wheel 24 and the needle roller 2. In order to eliminate the influence of the wear gap on the meshing of the cycloid wheel 24 and the needle roller 2, in this embodiment, as shown in FIG. Figure 2 As shown, each cycloid wheel 24 is configured to be a split structure including a first cycloid 25 and a second cycloid 26 respectively. The first cycloid 25 and the second cycloid 26 are coaxially arranged and their mutually adjacent sides are in contact with each other. A cycloid elastic anti-backlash structure 27 is provided between the first cycloid 25 and the second cycloid 26 that cooperate with each other. The cycloid elastic anti-backlash structure 27 drives the first cycloid 25 and the second cycloid 26 to rotate and dislocate along their circumferential direction.

[0045] like Figure 2 , Figure 3 and Figure 4As shown, in this embodiment, the cycloid elastic backlash elimination structure 27 includes a plurality of first backlash elimination semi-circular arc grooves 28 arranged in a circumferential array on the side of the first cycloid 25 close to the second cycloid 26, and a plurality of second backlash elimination semi-circular arc grooves 29 corresponding to the first backlash elimination semi-circular arc grooves 28 are arranged in a circumferential array on the side of the second cycloid 26 close to the first cycloid 25, and the number and position of the first backlash elimination semi-circular arc grooves 28 and the second backlash elimination semi-circular arc grooves 29 correspond to the number and position of the eccentric shaft holes 17 on the cycloid wheel 24. The ends of the first backlash elimination semi-circular arc grooves 28 and the second backlash elimination semi-circular arc grooves 29 corresponding to each other are staggered, and the projections of the first backlash elimination semi-circular arc grooves 28 and the second backlash elimination semi-circular arc grooves 29 matching each other on their mating surfaces intersect, and the intersecting parts constitute a circular hole coaxial therewith. A cycloid anti-backlash spring 30 is provided in the circular hole formed by the first anti-backlash semicircular groove 28 and the second anti-backlash semicircular groove 29 . One end of the cycloid anti-backlash spring 30 abuts against the end of the first anti-backlash semicircular groove 28 , and the other end abuts against the end of the second anti-backlash semicircular groove 29 .

[0046] like Figure 4 and Figure 5 As shown, the cycloid anti-backlash spring 30 is pre-compressed by the first anti-backlash semi-circular groove 28 and the second anti-backlash semi-circular groove 29, and the two ends of the cycloid anti-backlash spring 30 apply force to the first cycloid 25 and the second cycloid 26 through the ends of the first anti-backlash semi-circular groove 28 and the second anti-backlash semi-circular groove 29, respectively, and the cycloid anti-backlash spring 30 provides the first cycloid 25 and the second cycloid 26 with force to make them rotate relative to each other. When the cycloid wheel 24 and the eccentric shaft 16 and the needle roller and the retainer bearing 23 are worn and gaps are generated, the first cycloid 25 and the second cycloid 26 will rotate relative to each other under the elastic force of the cycloid anti-backlash spring 30, eliminating the gap between the cycloid wheel 24 and the eccentric shaft 16 and clamping the eccentric shaft 16, and the first cycloid 25 and the second cycloid 26 each have one side offset outward to mesh with the needle roller 2, thereby eliminating the wear gap between the cycloid wheel 24 and the needle roller 2, and ensuring the meshing accuracy between the cycloid wheel 24 and the needle roller 2.

[0047] like Figure 1 and Figure 6As shown, the end of the eccentric shaft 16 close to the output shaft 3 is equipped with a planetary gear 21 through a spline, and the two sides of the planetary gear 21 are provided with a second axial retaining ring 22 for axially limiting the planetary gear 21. The end of the input shaft 7 is equipped with an input gear 8 that meshes with the planetary gear 21, and the outer wall of the end of the input shaft 7 close to the input gear 8 is provided with an input shaft gear 9 that is integrally formed with the input gear 8 and meshes with the planetary gear 21. An input elastic clearance elimination structure 10 is provided between the input gear 8 and the end of the input shaft 7, and the input elastic clearance elimination structure 10 drives the input gear 8 to rotate displaced relative to the end of the input shaft 7 along its circumferential direction. Among them, the side of the input gear 8 away from the input shaft 7 is provided with a cap 14 that limits the axial position of the input gear 8 and is installed on the input shaft 7, and a rotation gap 15 is provided between the cap 14 and the input gear 8 to prevent the cap 14 from locking the input gear 8 and affecting the rotation of the input gear 8 relative to the input shaft 7. Among them, the input shaft 7 is installed on the motor (not shown in the figure) through a long pin, and the input shaft 7 is driven by the motor to drive the input gear 8 and the input shaft gear 9 to mesh with the planetary gear 21.

[0048] like Figure 6 and Figure 7 As shown, in this embodiment, the input elastic clearance eliminating structure 10 includes a plurality of third clearance eliminating semi-circular arc grooves 11 arranged in a circumferential array on the side of the input gear 8 close to the input shaft 7, and a plurality of fourth clearance eliminating semi-circular arc grooves 12 corresponding to the third clearance eliminating semi-circular arc grooves 11 are arranged in a circumferential array at the end of the input shaft 7, and the third clearance eliminating semi-circular arc grooves 11 and the fourth clearance eliminating semi-circular arc grooves 12 are matched one by one. The ends of the third clearance eliminating semi-circular arc grooves 11 and the fourth clearance eliminating semi-circular arc grooves 12 corresponding to each other are staggered, and their projected parts on the plane where the input shaft 7 and the input gear 8 fit each other intersect, and the intersecting parts constitute a circular hole coaxial with them. An input clearance eliminating spring 13 is arranged in the circular hole formed by each group of the third clearance eliminating semi-circular arc grooves 11 and the fourth clearance eliminating semi-circular arc grooves 12, and one end of the input clearance eliminating spring 13 abuts against the end of the third clearance eliminating semi-circular arc groove 11, and the other end abuts against the end of the fourth clearance eliminating semi-circular arc groove 12.

[0049] like Figure 7 and Figure 8As shown, the input clearance eliminating spring 13 is pre-compressed by the third clearance eliminating semi-circular arc groove 11 and the fourth clearance eliminating semi-circular arc groove 12, and the two ends of the input clearance eliminating spring 13 apply force to the input gear 8 and the input shaft 7 through the ends of the third clearance eliminating semi-circular arc groove 11 and the fourth clearance eliminating semi-circular arc groove 12, respectively, and the input clearance eliminating spring 13 provides the input gear 8 with a force to rotate relative to the input shaft 7 along its circumferential direction. In normal state, the input gear 8 and the input shaft gear 9 are meshed with the planetary gear 21 for transmission. When the input gear 8, the input shaft gear 9 and the planetary gear 21 are worn, and the input gear 8 and the input shaft 7 are worn, the input gear 8 can rotate relative to the input shaft 7 and stagger a certain amount, eliminating the gap between the input gear 8 and the planetary gear 21, so that the input gear 8 and the planetary gear 21 are closely meshed, and the meshing accuracy between the input gear 8 and the planetary gear 21 is ensured. At the same time, during the rotation of the planetary gear 21, the reverse clearance between the planetary gear 21 and the input shaft gear 9 is eliminated.

[0050] Working principle and use method of the present invention:

[0051] Cycloid elastic backlash elimination: The pre-compressed cycloid anti-backlash spring 30 provides the first cycloid 25 and the second cycloid 26 with a force to make them rotate relative to each other. Once the cycloid wheel 24, the eccentric shaft 16 and the needle roller and the retainer bearing 23 are worn, the cycloid anti-backlash spring 30 will cause the first cycloid 25 and the second cycloid 26 to rotate relative to each other by a certain amount, thereby eliminating the gap between the cycloid wheel 24 and the eccentric shaft 16 and clamping the eccentric shaft 16. In addition, one side of the first cycloid 25 and the second cycloid 26 is offset outward to mesh with the needle roller 2, thereby eliminating the wear gap between the cycloid wheel 24 and the needle roller 2 and ensuring the meshing accuracy between the cycloid wheel 24 and the needle roller 2.

[0052] Input elastic anti-backlash: The pre-compressed input backlash eliminating spring 13 provides the input gear 8 and the input shaft 7 with a force to rotate the input gear 8 relative to the input shaft 7. When the input gear 8, the input shaft gear 9 and the planetary gear 21 are worn, the input gear 8 can rotate relative to the input shaft 7 by a certain amount to eliminate the gap between the input gear 8 and the planetary gear 21, so that the input gear 8 and the planetary gear 21 are closely meshed, ensuring the meshing accuracy between the input gear 8 and the planetary gear 21. At the same time, during the rotation of the planetary gear 21, the reverse clearance between the planetary gear 21 and the input shaft gear 9 is eliminated.

[0053] High lifespan: After long-term use, the reducer will inevitably wear out, and the wear will cause gaps to form between mechanical parts. The cycloid elastic backlash elimination mechanism and the input elastic backlash elimination structure 10 in the present invention are both elastic self-backlash elimination mechanisms, which can eliminate the meshing gap caused by wear and extend the service life of the reducer.

[0054] High precision:The cycloid elastic backlash elimination mechanism and the input elastic backlash elimination structure 10 have elastic backlash elimination capabilities, which can reduce the meshing error caused by factors such as processing and assembly to a certain extent and improve the transmission accuracy.

[0055] Low Vibration: A major reason for the vibration of the reducer in its motion state is the inconsistency of the transmission state of the reducer. The cycloid elastic anti-backlash mechanism and the input elastic anti-backlash structure 10 in the present invention improve the meshing state between the cycloid wheel 24 and the needle roller 2, and between the planetary wheel 21 and the input gear 8, which can greatly reduce the vibration of the reducer during operation.

[0056] The above description shows and describes the preferred embodiments of the present invention. As mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the invention concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not depart from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A self-clearing RV reducer, characterized in that: The invention comprises a pinion housing (1), an output shaft (3), an output end cover (4), an input shaft (7), and at least two eccentric shafts (16) arranged in a circumferential array, wherein two cams of the eccentric shaft (16) are respectively provided with cycloidal wheels (24), a plurality of semicircular grooves are arranged in a circumferential array on the inner wall of the pinion housing (1), a needle roller (2) matching the needle roller is installed in the semicircular groove, and the outer wall of the cycloidal wheel (24) is in spur meshing with the needle roller (2); a planetary wheel (21) is installed at one end of the eccentric shaft (16) close to the output shaft (3), an input gear (8) in spur meshing with the planetary wheel (21) is provided at the end of the input shaft (7), and an input gear (8) in spur meshing with the planetary wheel (21) is provided on the outer wall of the end of the input shaft (7). An input shaft gear (9); two cycloid wheels (24) are respectively mounted on the cam of the eccentric shaft (16) via needle rollers and cage bearings (23); each cycloid wheel (24) comprises a first cycloid (25) and a second cycloid (26); a cycloid elastic clearance-eliminating structure (27) is provided between the first cycloid (25) and the second cycloid (26); the cycloid elastic clearance-eliminating structure (27) drives the first cycloid (25) and the second cycloid (26) to rotate and displace along their circumferential direction; an input elastic clearance-eliminating structure (10) is provided between the input gear (8) and the end of the input shaft (7); the input elastic clearance-eliminating structure (10) drives the input gear (8) to rotate and displace relative to the end of the input shaft (7) along its circumferential direction; The cycloid elastic backlash elimination structure (27) comprises a plurality of first backlash elimination semicircular arc grooves (28) arranged in a circumferential array on a side of the first cycloid (25) close to the second cycloid (26); a plurality of second backlash elimination semicircular arc grooves (29) corresponding to the first backlash elimination semicircular arc grooves (28) are arranged in a circumferential array on a side of the second cycloid (26) close to the first cycloid (25); the ends of the first backlash elimination semicircular arc grooves (28) and the second backlash elimination semicircular arc grooves (29) corresponding to each other are arranged in a staggered manner; the overlapping portion of the first backlash elimination semicircular arc groove (28) and the second backlash elimination semicircular arc groove (29) forms a circular hole, and a cycloid backlash elimination spring (30) is arranged in the circular hole; one end of the cycloid backlash elimination spring (30) abuts against the end of the first backlash elimination semicircular arc groove (28), and the other end abuts against the end of the second backlash elimination semicircular arc groove (29); The input elastic backlash elimination structure (10) comprises a plurality of third backlash elimination semicircular arc grooves (11) arranged in a circumferential array on a side of the input gear (8) close to the input shaft (7); a plurality of fourth backlash elimination semicircular arc grooves (12) corresponding to the third backlash elimination semicircular arc grooves (11) are arranged in a circumferential array at the end of the input shaft (7); the ends of the third backlash elimination semicircular arc grooves (11) and the fourth backlash elimination semicircular arc grooves (12) corresponding to each other are arranged in a staggered manner; the overlapping parts of the third backlash elimination semicircular arc grooves (11) and the fourth backlash elimination semicircular arc grooves (12) form a circular hole, and an input backlash elimination spring (13) is arranged in the circular hole; one end of the input backlash elimination spring (13) abuts against the end of the third backlash elimination semicircular arc groove (11), and the other end abuts against the end of the fourth backlash elimination semicircular arc groove (12).

2. The self-backlash eliminating structure RV reducer according to claim 1, characterized in that: A plurality of eccentric shaft holes (17) corresponding to the eccentric shaft (16) are arranged in a circular array on the first cycloid (25) and the second cycloid (26), and the number and positions of the first anti-backlash semi-circular arc grooves (28) and the second anti-backlash semi-circular arc grooves (29) correspond one-to-one to the eccentric shaft holes (17).

3. A self-backlash eliminating structure RV reducer according to claim 1 or 2, characterized in that: The cycloid anti-backlash spring (30) is pre-compressed by the first anti-backlash semi-circular arc groove (28) and the second anti-backlash semi-circular arc groove (29), providing relative rotation force for the first cycloid (25) and the second cycloid (26); when wear occurs between the cycloid wheel (24), the eccentric shaft (16), the needle roller and the retaining frame bearing (23), the cycloid anti-backlash spring (30) causes the first cycloid (25) and the second cycloid (26) to rotate and misalign, thereby eliminating the wear gap between the cycloid wheel (24) and the needle roller (2) and the eccentric shaft (16).

4. The self-backlash eliminating structure RV reducer according to claim 1, characterized in that: The input backlash eliminating spring (13) is pre-compressed by the third backlash eliminating semicircular arc groove (11) and the fourth backlash eliminating semicircular arc groove (12) to provide relative rotational force for the input gear (8) and the input shaft (7). When wear occurs between the input gear (8), the input shaft gear (9) and the planetary gear (21), the input backlash eliminating spring (13) causes the input gear (8) to rotate relative to the input shaft (7) to eliminate the wear clearance between the input gear (8) and the planetary gear (21), and eliminates the reverse clearance between the planetary gear (21) and the input shaft gear (9) during the rotation of the planetary gear (21).

5. A self-backlash eliminating structure RV reducer according to claim 1 or 4, characterized in that: A retaining cap (14) is provided on a side of the input gear (8) away from the input shaft (7), and a rotation gap (15) is provided between the retaining cap (14) and the input gear (8).

6. The self-backlash eliminating structure RV reducer according to claim 1, characterized in that: A mounting bearing (5) is provided between the outer circle of the output shaft (3) and the outer circle of the output end cover (4) and the inner circle of the pin gear housing (1), and the mounting bearing (5) is one of a tapered roller bearing, a deep groove ball bearing, and an angular contact ball bearing; a skeleton sealing ring (6) is provided between the output shaft (3) and the pin gear housing (1), and the skeleton sealing ring (6) is located on a side of the two mounting bearings (5) that are away from each other.

7. The self-backlash eliminating structure RV reducer according to claim 1, characterized in that: The two ends of the eccentric shaft (16) are respectively positioned and rotatably mounted on the output shaft (3) and the output end cover (4) via first tapered roller bearings (18), and a cushion block (19) is provided on a side of the first tapered roller bearing (18) close to the cam on the eccentric shaft (16), and a first axial retaining ring (20) is provided on a side of the two first tapered roller bearings (18) away from each other.

8. The self-backlash eliminating structure RV reducer according to claim 1, characterized in that: The planetary gear (21) is mounted on one end of the eccentric shaft (16) close to the output shaft (3) via a spline, and second axial retaining rings (22) are provided on both sides of the planetary gear (21).

Images