A zero backlash self-adjusting structure RV reducer

Abstract

The present invention provides a zero-backlash self-adjusting structure RV reducer, which relates to the technical field of reducers, including a pinion gear housing, an output shaft, an output end cover, an input shaft, and an eccentric shaft. A bevel-toothed cycloid wheel is installed on the eccentric cam of the eccentric shaft, a bevel-toothed planetary wheel is installed at one end of the eccentric shaft close to the output end cover, and an input bevel gear meshing with the bevel gear planetary wheel bevel gear is installed at the end of the input shaft; a plurality of conical semicircular grooves are arranged in a circumferential array on the inner wall of the pinion gear housing, needle rollers are installed in the conical semicircular grooves, and a plurality of conical outer teeth meshing with the bevel gear of the needle roller are arranged in a circumferential array on the outer wall of the bevel-toothed cycloid wheel; an output anti-backlash structure is arranged at one end of the eccentric shaft close to the output shaft, and the output anti-backlash structure drives the eccentric shaft as a whole to deviate along its axial direction; an input anti-backlash structure is arranged at one end of the eccentric shaft close to the output end cover, and the input anti-backlash structure drives the bevel gear planetary wheel to deviate relative to the eccentric shaft along its axis. The present invention has the characteristics of elastic anti-backlash capability and zero backlash, high life, high precision, and low vibration.

Description

Technical Field

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

[0002] The gear transmission inside the reducer generally has a certain amount of tooth clearance to prevent errors such as processing and assembly, to avoid the teeth from getting stuck during the transmission process, or to meet lubrication requirements. When the teeth are meshing, the existence of tooth clearance and processing and assembly errors will cause discontinuity in the gear meshing transmission process, thereby causing vibration and transmission deviation.

[0003] In addition, 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

[0004] The purpose of the present invention is to provide a zero-backlash self-adjusting structure RV reducer, which has elastic backlash elimination capability by arranging bevel gear matching and arranging input backlash elimination structure and output backlash elimination structure at both ends of the eccentric shaft. It can not only eliminate the adverse effects of the meshing process caused by processing and assembly errors, but also eliminate the backlash that increases due to a certain amount of wear value after long-term operation of the reducer, so that the reducer can still maintain zero backlash, high precision, high rigidity and low vibration after a certain amount of wear.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions:

[0006] A zero-backlash self-adjusting structure RV reducer comprises a pinion gear housing, an output shaft, an output end cover, an input shaft, and at least two eccentric shafts arranged in a circumferential array, wherein two eccentric cams of the eccentric shaft are respectively mounted with bevel-toothed cycloidal wheels, an end of the eccentric shaft close to the output end cover is limitedly mounted with a bevel-toothed planetary wheel, an input bevel gear is mounted on the end of the input shaft, and bevel teeth of the input bevel gear and the bevel-toothed planetary wheel are meshed; a plurality of conical semicircular grooves are arranged in a circumferential array on the inner wall of the pinion gear housing, needle rollers matching therewith are arranged in the conical semicircular grooves, and a plurality of conical outer teeth meshing with the bevel teeth of the needle rollers are arranged in a circumferential array on the outer wall of the bevel-toothed cycloidal wheel; an output anti-backlash structure is arranged at one end of the eccentric shaft close to the output shaft, and the output anti-backlash structure drives the eccentric shaft to drive the bevel-toothed cycloidal wheel to deviate along its axial direction as a whole; an input anti-backlash structure is arranged at one end of the eccentric shaft close to the output end cover, and the input anti-backlash structure drives the bevel-toothed planetary wheel to deviate relative to the eccentric shaft along its axis.

[0007] By adopting the above technical solution, the conical outer teeth on the outer wall of the bevel cycloid wheel are meshed with the needle roller. When there is a gap between the bevel cycloid wheel and the needle roller, the output clearance elimination structure drives the eccentric shaft to shift along its axial direction as a whole. In the process of the eccentric shaft driving the cycloid wheel to move along its axial direction, the conical outer teeth of the bevel cycloid wheel and the needle roller are tightly meshed under the action of conical meshing, thereby eliminating the meshing gap between the two. Similarly, the bevel gear planetary gear is meshed with the input bevel gear. When there is a gap between the bevel gear planetary gear and the input bevel gear, the input clearance structure drives the bevel gear planetary gear to shift relative to the eccentric shaft along its axis. In the process of the bevel gear planetary gear shifting along the eccentric shaft, the bevel gear planetary gear and the input bevel gear are tightly meshed under the action of conical meshing, thereby eliminating the gap between the two.

[0008] The present invention can eliminate the tooth gap between the bevel gear cycloid wheel and the needle roller and between the bevel gear planetary wheel and the input bevel gear by setting and meshing bevel gears between the bevel gear cycloid wheel and the needle roller and between the bevel gear planetary wheel and the input bevel gear, and respectively setting an output clearance elimination structure and an input clearance elimination structure at both ends of the eccentric shaft, thereby achieving zero tooth gap. After long-term use, the reducer will inevitably produce wear, and wear will cause gaps to be generated between seasonal components. The above structure can eliminate the meshing gap caused by wear, extend the service life of the reducer, and improve the transmission accuracy of the reducer. Moreover, the improvement of the meshing condition can greatly reduce the vibration of the reducer during operation. Therefore, the present invention has the characteristics of zero tooth gap, high life, high precision, and low vibration.

[0009] Furthermore, the output clearance eliminating structure includes a first cover arranged on the output shaft, the first cover is located in the circular hole of the output shaft for mounting the eccentric shaft, and a first butterfly spring piece cooperating with the end of the eccentric shaft is provided on the side of the first cover close to the eccentric shaft.

[0010] By adopting the above technical solution, the first butterfly spring is pre-compressed to a certain deformation amount by locking the first cover, and the elastic force of the first butterfly spring is used to make the eccentric shaft drive the conical outer teeth of the bevel gear cycloid wheel to mesh closely with the needle roller, and the meshing clearance between the bevel gear cycloid wheel and the needle roller is elastically eliminated. Since the first butterfly spring is elastic, one side of the bevel gear cycloid wheel has a certain yielding ability. When the bevel gear cycloid wheel meshes with the needle roller, it will not get stuck during the meshing process due to errors such as processing and assembly. The structure is simple, easy to operate and has obvious effects.

[0011] Furthermore, a first cushion block is provided on a side of the first butterfly-shaped spring piece away from the first cover, a ball is installed on a side of the first cushion block away from the first butterfly-shaped spring piece, and the ball is in rolling cooperation with the end of the eccentric shaft.

[0012] By adopting the above technical solution, the rolling cooperation of the ball and the eccentric shaft is utilized to reduce the wear of the first butterfly spring piece caused by the high-speed rotation of the eccentric shaft. The first pad realizes the installation of the ball and separates the ball and the first butterfly spring piece, thereby ensuring the working effect and service life of the first butterfly spring piece. The structure is simple and the effect is obvious.

[0013] Furthermore, a rolling ring groove coaxial with the eccentric shaft is provided on one side of the first cushion block away from the first butterfly spring piece, and a plurality of balls are provided in an array along the circumference of the rolling ring groove and are all positioned and rollingly installed in the rolling ring groove.

[0014] By adopting the above technical solution, the ball is rolled and installed in the rolling ring groove, so as to realize the positioning rolling installation of the ball, prevent the ball from being separated during the rolling process, and ensure the rolling cooperation between the ball and the end of the eccentric shaft. Among them, there are several balls in the circumferential array of balls, and several balls are arranged to disperse the rolling friction of the eccentric shaft on the ball, so as to improve the use effect and service life of the ball, and the structure is simple and the effect is obvious.

[0015] Furthermore, the first cover locks and pre-presses the first butterfly-shaped spring piece, and the first butterfly-shaped spring piece supports the end of the eccentric shaft through the first gasket and the ball, and the eccentric shaft drives the bevel-toothed cycloidal wheel to move synchronously, and the conical outer teeth of the bevel-toothed cycloidal wheel are tightly engaged with the needle roller, elastically eliminating the tooth gap between the bevel-toothed cycloidal wheel and the needle roller.

[0016] By adopting the above technical solution, the first butterfly spring is pre-compressed to a certain deformation amount by locking the first cover, so that the first cushion block presses the ball against the end of the eccentric shaft, and then the eccentric shaft drives the bevel cycloid wheel to move synchronously, so that the conical outer teeth of the bevel cycloid wheel and the needle roller are tightly meshed, and the meshing clearance between the bevel cycloid wheel and the needle roller is elastically eliminated. In addition, due to the elasticity of the first butterfly spring, one side of the bevel cycloid wheel has a certain yielding ability, and when the bevel cycloid wheel and the needle roller are meshed, there will be no jamming during the meshing process due to errors such as processing and assembly.

[0017] Furthermore, the bevel planetary gear is installed at one end of the eccentric shaft through a spline, the input bevel gear is installed on the input shaft through a spline, and a second gasket is provided on the side of the input bevel gear close to the output end cover; the input anti-backlash structure includes a second butterfly spring piece arranged on the side of the bevel planetary gear away from the bevel cycloid gear, a nut is provided on the side of the second butterfly spring piece away from the bevel planetary gear to lock it on the eccentric shaft, and a shaft retaining ring is provided on the side of the bevel planetary gear away from the second butterfly spring piece.

[0018] By adopting the above technical solution, the input bevel gear is installed on the input shaft through the spline and fixed by the second pad, the bevel planetary gear is installed on the eccentric wheel through the spline, and the second butterfly spring is pre-compressed by a certain amount by adjusting the nut, and a certain force along the axial direction is applied to the bevel planetary gear, so that the bevel planetary gear and the input bevel gear are closely meshed, thereby eliminating the tooth gap between the two. Since the second butterfly spring is elastic, the bevel planetary gear has a certain yielding ability, and when the bevel planetary gear and the input bevel gear are meshed, it will not get stuck during the meshing process due to errors such as processing and assembly.

[0019] Furthermore, the nut is locked to pre-compress the second butterfly spring piece, and the outer teeth of the bevel planetary gear are tightly meshed with the outer teeth of the input bevel gear under the elastic force of the second butterfly spring piece, so as to elastically eliminate the backlash between the bevel planetary gear and the input bevel gear.

[0020] By adopting the above technical solution, the second butterfly spring piece is pre-compressed by a certain amount by adjusting the nut, and a certain force is applied to the bevel planetary gear along its axial direction, so that the bevel planetary gear and the input bevel gear are closely meshed, thereby eliminating the tooth gap between the two. In addition, due to the elasticity of the second butterfly spring piece, the bevel planetary gear has a certain yielding ability, and when the bevel planetary gear and the input bevel gear are meshed, the bevel planetary gear will not get stuck during the meshing process due to errors such as processing and assembly.

[0021] Furthermore, mounting bearings are respectively 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 mounting bearings are one of tapered roller bearings, angular contact ball bearings or deep groove ball bearings; 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 of the mounting bearing close to it away from the output end cover.

[0022] By adopting the above technical solution, the output shaft and the output end cover are installed on the pinion housing through the mounting bearings. The assembly consisting of the output shaft and the output end cover can make relative rotational motion with the pinion housing. The skeleton sealing ring is installed between the output shaft and the pinion housing to achieve sealing between the two, thereby improving the sealing performance of the reducer.

[0023] Furthermore, each of the bevel-toothed cycloidal wheels is mounted on a corresponding cam on the eccentric shaft through two groups of double-row tapered rollers arranged in a circumferential array, and the outer wall of the cam of the eccentric shaft and the inner wall of the bevel-toothed cycloidal wheel serve as the inner ring and outer ring of the double-row tapered roller limit installation respectively.

[0024] By adopting the above technical solution, the bevel gear cycloid wheel is installed on the cam of the eccentric shaft through double-row tapered rollers, and the outer wall of the cam of the eccentric shaft and the outer inner wall of the bevel gear cycloid wheel are respectively used as the inner ring and outer ring of the double-row tapered roller limit installation, and the double-row tapered roller is limitedly installed between the two, which is equivalent to forming a double-row tapered roller bearing. However, compared with the needle roller and cage bearing used in the existing reducer, the bevel gear cycloid wheel and the eccentric shaft can only rotate relative to each other, and cannot move axially, thereby ensuring that the output anti-backlash structure can drive the eccentric shaft to drive the bevel gear cycloid wheel to move synchronously along its axial direction, and ensure the anti-backlash effect between the bevel gear cycloid wheel and the needle roller. Among them, each bevel gear cycloid wheel corresponds to a double-row tapered roller, one of the double-row tapered rollers is used to realize the installation of the bevel gear cycloid wheel, ensuring that the eccentric shaft can drive the bevel gear cycloid wheel to move synchronously, so that the bevel gear cycloid wheel can be closely meshed with the needle roller, and the other row is used to offset the unilateral force of the bevel gear cycloid wheel to avoid causing instability of the overall structure.

[0025] Furthermore, both ends of the input shaft are respectively installed on the output shaft and the output end cover through first tapered roller bearings, the outer rings of the two first tapered roller bearings are respectively fixed by hole retaining springs, and the two hole retaining springs are located on the side of the two first tapered roller bearings away from each other; a limiting step is provided on the outer wall of the input shaft, and the inner ring of the first tapered roller bearing is clamped on the limiting step.

[0026] By adopting the above technical solution, two first tapered roller bearings are used to realize the rotational installation between the input shaft, the output shaft and the output end cover, and under the limiting and fixing action of the hole retaining spring and the limiting step, the limiting and fixing of the inner rings and outer rings of the two first tapered roller bearings are realized, thereby ensuring the stability of the installation and working effect of the first tapered roller bearings.

[0027] In summary, the present invention has the following beneficial effects:

[0028] 1. The present invention can eliminate the backlash between the bevel-tooth cycloid wheel and the needle roller and between the bevel-tooth planetary wheel and the input bevel gear by setting and meshing bevel gears between the bevel-tooth cycloid wheel and the needle roller and between the bevel-tooth planetary wheel and the input bevel gear, and respectively setting an output backlash elimination structure and an input backlash elimination structure at both ends of the eccentric shaft, thereby eliminating the backlash between the bevel-tooth cycloid wheel and the needle roller and the backlash between the input bevel-tooth planetary wheel and the input bevel gear, thereby achieving zero backlash;

[0029] 2. After long-term use, the reducer will inevitably wear out, and wear will cause gaps between mechanical parts. The output anti-backlash structure and the input anti-backlash structure in the present invention are both elastic zero-backlash self-adjusting structures, which can eliminate the meshing gap caused by wear and extend the service life of the reducer;

[0030] 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 output anti-backlash structure and the input anti-backlash structure in the present invention are both elastic zero-backlash self-adjusting and have elastic anti-backlash capability, 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;

[0031] 4. A major reason for the vibration of the reducer in motion is due to the inconsistent transmission state of the reducer. The output anti-backlash structure and the input anti-backlash structure in the present invention improve the meshing state between the bevel cycloid wheel and the needle roller, and between the bevel planetary wheel and the input bevel gear, which can greatly reduce the vibration of the reducer during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of a zero-backlash self-adjusting RV reducer;

[0033] Figure 2 yes Figure 1 A magnified view of part A;

[0034] Figure 3 It is a schematic diagram of the overall structure of a zero-backlash self-adjusting RV reducer, which is used to reflect the structure of the ball in another embodiment;

[0035] Figure 4 yes Figure 3 Enlarged view of part B.

[0036] In the figure, 1, needle gear housing; 2, conical semicircular groove; 3, needle roller; 4, output shaft; 5, output end cover; 6, mounting bearing; 7, skeleton sealing ring; 8, input shaft; 9, first tapered roller bearing; 10, hole retaining ring; 11, limiting step; 12, eccentric shaft; 13, retaining rack needle roller bearing; 14, second cover; 15, bevel gear cycloid wheel; 16, double row tapered roller; 17, bevel gear planetary gear; 18, input bevel gear; 19, output anti-backlash structure; 20, first cover; 21, first butterfly spring piece; 22, first gasket; 221, rolling groove; 222, rolling ring groove; 23, ball; 24, input anti-backlash structure; 25, second gasket; 26, second butterfly spring piece; 27, nut; 28, shaft retaining ring. DETAILED DESCRIPTION

[0037] 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.

[0038] A zero backlash self-adjusting structure RV reducer, such as Figure 1As shown, it includes a needle gear housing 1, an output shaft 4, an output end cover 5, an input shaft 8, two or three (three in this embodiment) eccentric shafts 12 arranged in a circumferential array, the output shaft 4 and the output end cover 5 are fixed and assembled into a coaxial assembly with the needle gear housing 1 by screws and pins, and mounting bearings 6 are respectively arranged between the outer circle of the output shaft 4 and the outer circle of the output end cover 5 and the inner circle of the needle gear housing 1, so that the assembly composed of the output shaft 4 and the output end cover 5 can rotate relative to the needle gear housing 1. Among them, the mounting bearing 6 is one of a tapered roller bearing, an angular contact ball bearing or a deep groove ball bearing. In this embodiment, the mounting bearing 6 is a tapered roller bearing. In addition, a skeleton sealing ring 7 is arranged between the output shaft 4 and the needle gear housing 1, and the skeleton sealing ring 7 is located on the side of the mounting bearing 6 close to it away from the output end cover 5, so as to achieve sealing between the output shaft 4 and the needle gear housing 1.

[0039] like Figure 1 As shown, a plurality of circular holes cooperating with a plurality of eccentric shafts 12 are arranged in a circumferential array on the output shaft 4 and the output end cover 5, and both ends of the eccentric shaft 12 are respectively installed in the corresponding circular holes on the output shaft 4 and the output end cover 5 through the retainer needle bearings 13, so that the eccentric shaft 12 can rotate relative to the assembly composed of the output shaft 4 and the output end cover 5 and move axially in a small range. Among them, a second cover 14 cooperating with the eccentric shaft 12 and the retainer needle bearing 13 is arranged on the output end cover 5, and the second cover 14 is used to prevent the retainer needle bearing 13 and the eccentric shaft 12 from slipping out.

[0040] like Figure 1 As shown, two bevel gear cycloid wheels 15 are respectively installed on the eccentric shaft 12, and a plurality of conical semicircular grooves 2 are arranged in a circumferential array on the inner wall of the pin gear housing 1. The conical semicircular grooves 2 are arranged in two groups and correspond to the two bevel gear cycloid wheels 15 respectively. The conical semicircular grooves 2 are equipped with needle rollers 3 matched therewith, and a plurality of conical external teeth meshing with the bevel gears of the needle rollers 3 are arranged in a circumferential array on the outer wall of the bevel gear cycloid wheel 15. Among them, the conical semicircular grooves 2 have a certain taper, and the end thereof close to the output end cover 5 is a small head structure. Similarly, the conical external teeth on the outer wall of the bevel gear cycloid wheel 15 are also a small head structure at the end close to the output end cover 5.

[0041] like Figure 1 and Figure 2As shown, an output clearance eliminating structure 19 is provided at one end of the eccentric shaft 12 close to the output shaft 4, and the output clearance eliminating structure 19 drives the eccentric shaft 12 to drive the bevel gear cycloidal wheel 15 to deviate along its axial direction as a whole. In this embodiment, the output clearance eliminating structure 19 includes a first cover 20, a first butterfly spring piece 21, a first cushion block 22 and a ball 23, which are arranged in the circular hole of the output shaft 4 where the eccentric shaft 12 is installed. The ball 23 is rollingly matched with the end of the eccentric shaft 12 close to the output shaft 4, and the ball 23 is rollingly installed on the side wall of the first cushion block 22; the first butterfly spring piece 21 is located on the side of the first cushion block 22 away from the ball 23, and the first cover 20 is located on the side of the first butterfly spring piece 21 away from the first cushion block 22.

[0042] like Figure 1 and Figure 2 As shown, the first butterfly spring piece 21 is pre-compressed to a certain deformation amount by locking the cover, so that the first cushion block 22 presses the ball 23 against the end of the eccentric shaft 12, and then the eccentric shaft 12 drives the bevel cycloid wheel 15 to move synchronously, so that the conical outer teeth of the bevel cycloid wheel 15 are tightly meshed with the needle roller 3, and the meshing clearance between the bevel cycloid wheel 15 and the needle roller 3 is elastically eliminated. When the bevel cycloid wheel 15 and the needle roller 3 are worn after working for a long time, the first butterfly spring piece 21 drives the eccentric shaft 12 to drive the bevel cycloid wheel 15 to move slightly toward the side close to the output end cover 5, so that the conical outer teeth of the bevel cycloid wheel 15 are always tightly meshed with the needle roller 3, avoiding the generation of a gap between the bevel cycloid wheel 15 and the needle roller 3. In addition, due to the elasticity of the first butterfly spring piece 21, one side of the bevel cycloid wheel 15 has a certain yield ability. When the bevel cycloid wheel 15 is meshed with the needle roller 3, no jamming will occur during the meshing process due to errors in processing and assembly.

[0043] The material, structure, pre-compression deformation, etc. of the first butterfly spring piece 21 can be selected according to the meshing force requirements of the bevel gear cycloid wheel 15 and the needle roller 3, the output torque of the output side, etc. The taper range of the conical semicircular groove 2 and the conical outer teeth on the bevel gear cycloid wheel 15 is 1:10-1:200. In addition, in other embodiments, the first butterfly spring piece 21 can also be replaced by a spring.

[0044] like Figure 1 As shown, each bevel gear cycloid wheel 15 is respectively mounted on two cams of the eccentric shaft 12 by double-row tapered rollers 16, and the outer wall of the cam of the eccentric shaft 12 and the inner wall of the bevel gear cycloid wheel 15 are respectively used as the inner ring and outer ring of the double-row tapered rollers 16 for limiting installation. In this way, under the limiting and fixing action of the outer wall of the cam of the eccentric shaft 12 and the inner wall of the bevel gear cycloid wheel 15, the bevel gear cycloid wheel 15 and the eccentric shaft 12 can only rotate relative to each other, and cannot move axially, ensuring that the output clearance elimination structure 19 can drive the bevel gear cycloid wheel 15 to move synchronously by driving the eccentric shaft 12 to move, thereby eliminating the gap between the bevel gear cycloid wheel 15 and the needle roller 3.

[0045] The reason why each bevel cycloid wheel 15 is installed with a double row of tapered rollers 16 is that the bevel cycloid wheel 15 is eccentrically meshed with the needle roller 3, and the tapered meshing will cause the bevel cycloid wheel 15 to bear a unilateral axial force after the meshing side is stressed, and the non-meshing side cannot offset the axial force because there is no meshing. Therefore, in order to offset the axial force, a double row of tapered rollers 16 is set, one row is used for the eccentric shaft 12 to drive the bevel cycloid wheel 15 to move synchronously, so that the bevel cycloid wheel 15 can be tightly meshed with the needle roller 3, and the other row is used to offset the unilateral force of the bevel cycloid wheel 15 to avoid causing instability of the overall structure.

[0046] like Figure 1 and Figure 2 As shown, in this embodiment, a ball 23 is provided and located on the axis of the eccentric shaft 12, and a rolling groove 221 is provided on the first cushion block 22 to cooperate with the ball 23. The rolling cooperation between the ball 23 and the eccentric shaft 12 is utilized to reduce the wear of the first butterfly spring piece 21 caused by the high-speed rotation of the eccentric shaft 12, thereby ensuring the working effect and service life of the first butterfly spring piece 21. Figure 3 and Figure 4 As shown, in another embodiment, the balls 23 are arranged in a circular array around the axis of the eccentric shaft 12, and the first cushion block 22 is provided with a rolling ring groove 222 coaxial with the eccentric shaft 12, and the balls 23 are positioned and rolled in the rolling ring groove 222. In this way, the balls 23 are arranged to increase the rolling contact points, disperse the rolling friction of the eccentric shaft 12 on the balls 23, and improve the use effect and service life of the balls 23. Of course, in order to avoid friction between adjacent balls 23, a retainer (not shown in the figure) that cooperates with the balls 23 can be arranged in the rolling ring groove 222 to limit the installation of the balls 23, thereby further improving the service life of the balls 23.

[0047] like Figure 1 As shown, both ends of the input shaft 8 are respectively installed in the center hole of the assembly consisting of the output shaft 4 and the output end cover 5 through the first tapered roller bearings 9, and the outer rings of the two first tapered roller bearings 9 are respectively fixed to the center holes of the output shaft and the output end cover 5 through the hole retaining rings 10, and the two hole retaining rings 10 are located on the side away from each other of the two first tapered roller bearings 9. A limiting step 11 is provided on the outer wall of the input shaft 8, and the inner ring of the first tapered roller bearing 9 is clamped on the limiting step 11. Of course, in other embodiments, the input shaft 8 can also be fixed directly on the motor instead of being fixed inside the reducer.

[0048] like Figure 1As shown, a bevel planetary gear 17 is installed through a spline at one end of the eccentric shaft 12 close to the output end cover 5, and an input bevel gear 18 is installed through a spline at the end of the input shaft 8, and the bevel gears of the input bevel gear 18 and the bevel planetary gear 17 are meshed, and the bevel teeth of the outer wall of the bevel planetary gear 17 close to the bevel cycloidal gear 15 are of a small head structure, and the side of the input bevel gear 18 close to the bevel cycloidal gear 15 is of a large head structure. A second cushion block 25 is sleeved on the input shaft 8, and the second cushion block 25 is located between the input bevel gear 18 and the inner ring of the first tapered roller bearing 9 close to it.

[0049] like Figure 1 As shown, an input clearance-eliminating structure 24 is provided at one end of the eccentric shaft 12 close to the output end cover 5, and the input clearance-eliminating structure 24 drives the bevel gear planetary gear 17 to deviate along its axis relative to the eccentric shaft 12. In this embodiment, the input clearance-eliminating structure 24 includes a second butterfly spring piece 26 provided on the side of the bevel gear planetary gear 17 away from the bevel gear cycloidal gear 15, a nut 27 for locking the second butterfly spring piece 26 on the eccentric shaft 12 is provided on the side of the bevel gear planetary gear 17 away from the bevel gear planetary gear 17, and a shaft retaining ring 28 is provided on the side of the bevel gear planetary gear 17 away from the second butterfly spring piece 26.

[0050] like Figure 1 As shown, by adjusting the nut 27 to pre-compress the second butterfly spring piece 26 to a certain amount, a certain force is applied to the bevel planetary gear 17 along its axial direction, so that the bevel planetary gear 17 is closely meshed with the input bevel gear 18, thereby eliminating the backlash between the two. When the bevel planetary gear 17 and the input bevel gear 18 are worn after working for a long time, the bevel planetary gear 17 is driven to move slightly toward the bevel cycloidal gear 15 under the elastic force of the second butterfly spring piece 26, so as to avoid the generation of a gap between the bevel cycloidal gear 15 and the input bevel gear 18. In addition, due to the elasticity of the second butterfly spring piece 26, the bevel planetary gear 17 has a certain yielding ability, and when the bevel planetary gear 17 is meshed with the input bevel gear 18, it will not get stuck during the meshing process due to errors such as processing and assembly.

[0051] The material, structure, pre-compression deformation, etc. of the second butterfly spring piece 26 can be selected according to the meshing force requirements and rated torque of the bevel planetary gear 17 and the input bevel gear 18, and the taper range of the conical outer teeth of the bevel planetary gear 17 and the input bevel gear 18 is 1:10-1:200. In addition, in other embodiments, the second butterfly spring piece 26 can also be replaced by a spring.

[0052] Working principle and use method of the present invention:

[0053] Output side anti-backlash:The first butterfly spring 21 is pre-compressed to a certain deformation amount by locking the cover, so that the first cushion block 22 presses the ball 23 against the end of the eccentric shaft 12, and then the eccentric shaft 12 drives the bevel cycloid wheel 15 to move synchronously, so that the conical outer teeth of the bevel cycloid wheel 15 are tightly meshed with the needle roller 3, and the meshing clearance between the bevel cycloid wheel 15 and the needle roller 3 is elastically eliminated. When the bevel cycloid wheel 15 and the needle roller 3 are worn after working for a long time, the first butterfly spring 21 drives the eccentric shaft 12 to drive the bevel cycloid wheel 15 to move slightly toward the side close to the output end cover 5, so that the conical outer teeth of the bevel cycloid wheel 15 are always tightly meshed with the needle roller 3, avoiding the generation of a gap between the bevel cycloid wheel 15 and the needle roller 3.

[0054] Input side anti-backlash: By adjusting the nut 27 to pre-compress the second butterfly spring piece 26 to a certain amount, a certain force is applied to the bevel planetary gear 17 along its axial direction, so that the bevel planetary gear 17 is closely meshed with the input bevel gear 18, thereby eliminating the backlash between the two. When the bevel planetary gear 17 and the input bevel gear 18 are worn after working for a long time, the bevel planetary gear 17 is driven to move slightly toward the bevel cycloidal gear 15 under the elastic force of the second butterfly spring piece 26, thereby avoiding the generation of a gap between the bevel cycloidal gear 15 and the input bevel gear 18.

[0055] High lifespan: After long-term use, the reducer will inevitably wear out, and wear will cause gaps to form between mechanical parts. The output anti-backlash structure 19 and the input anti-backlash structure 24 in the present invention are both elastic zero-backlash self-adjusting structures, which can eliminate the meshing gap caused by wear and extend the service life of the reducer.

[0056] High precision: Due to the elasticity of the first butterfly spring piece 21 and the second butterfly spring piece 26, the side of the bevel gear cycloid wheel 15 close to the output anti-backlash structure 19 and the side of the bevel gear planetary wheel 17 close to the input anti-backlash structure 24 have a certain yield ability. When the bevel gear cycloid wheel 15 is meshed with the needle roller 3 and the bevel gear planetary wheel 17 is meshed with the input bevel gear 18, no jamming will occur during the meshing process due to errors such as processing and assembly, thereby reducing the meshing errors caused by factors such as processing and assembly and improving the transmission accuracy.

[0057] Low Vibration: A major reason for the vibration of the reducer in motion is due to the inconsistent transmission state of the reducer. The output anti-backlash structure 19 and the input anti-backlash structure 24 in the present invention improve the meshing state between the bevel cycloid wheel 15 and the needle roller 3, and between the bevel planetary wheel 17 and the input bevel gear 18, which can greatly reduce the vibration of the reducer during operation.

[0058] 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 zero backlash self-adjusting structure RV reducer, characterized in that: The invention comprises a pinion gear housing (1), an output shaft (4), an output end cover (5), an input shaft (8), and at least two eccentric shafts (12) arranged in a circumferential array, wherein two eccentric cams of the eccentric shaft (12) are respectively provided with bevel gear cycloid wheels (15) in a limited manner, an end of the eccentric shaft (12) close to the output end cover (5) is provided with a bevel gear planetary wheel (17), an input bevel gear (18) is provided at the end of the input shaft (8), and bevel gears of the input bevel gear (18) and the bevel gear planetary wheel (17) are meshed with each other; a plurality of conical semicircular grooves (2) are provided in a circumferential array on the inner wall of the pinion gear housing (1), and the conical semicircular grooves (2) are provided in a circumferential array on the inner wall of the pinion gear housing (1). A needle roller (3) matched with the needle roller (3) is installed in the groove (2); a plurality of conical external teeth meshing with the conical teeth of the needle roller (3) are arranged in a circumferential array on the outer wall of the bevel gear cycloid wheel (15); an output clearance-eliminating structure (19) is arranged at one end of the eccentric shaft (12) close to the output shaft (4); the output clearance-eliminating structure (19) drives the eccentric shaft (12) to drive the bevel gear cycloid wheel (15) to deviate along its axial direction as a whole; an input clearance-eliminating structure (24) is arranged at one end of the eccentric shaft (12) close to the output end cover (5); the input clearance-eliminating structure (24) drives the bevel gear planetary wheel (17) to deviate along its axis relative to the eccentric shaft (12); The output clearance-eliminating structure (19) comprises a first cover (20) arranged on the output shaft (4), the first cover (20) being located in a circular hole of the output shaft (4) for mounting the eccentric shaft (12), and a first butterfly-shaped spring piece (21) cooperating with an end of the eccentric shaft (12) is provided on a side of the first cover (20) close to the eccentric shaft (12); A first cushion block (22) is provided on a side of the first butterfly-shaped spring piece (21) away from the first cover (20), a ball (23) is installed on a side of the first cushion block (22) away from the first butterfly-shaped spring piece (21), and the ball (23) is in rolling engagement with the end of the eccentric shaft (12); The bevel gear planetary wheel (17) is mounted on one end of the eccentric shaft (12) via a spline, the input bevel gear (18) is mounted on the input shaft (8) via a spline, and a second gasket (25) is provided on a side of the input bevel gear (18) close to the output end cover (5); the input clearance eliminating structure (24) comprises a second butterfly spring piece (26) arranged on a side of the bevel gear planetary wheel (17) away from the bevel gear cycloid wheel (15), a nut (27) for locking the second butterfly spring piece (26) on the eccentric shaft (12) is provided on a side of the bevel gear planetary wheel (17) away from the second butterfly spring piece (26), and a shaft retaining ring (28) is provided on a side of the bevel gear planetary wheel (17) away from the second butterfly spring piece (26).

2. The zero backlash self-adjusting structure RV reducer according to claim 1, characterized in that: A rolling ring groove (222) coaxial with the eccentric shaft (12) is provided on one side of the first cushion block (22) away from the first butterfly spring piece (21), and a plurality of balls (23) are arranged in an array along the circumference of the rolling ring groove (222) and are all positioned and rollingly mounted in the rolling ring groove (222).

3. A zero backlash self-adjusting structure RV reducer according to claim 1 or 2, characterized in that: The first sealing cover (20) locks and pre-presses the first butterfly-shaped spring sheet (21), and the first butterfly-shaped spring sheet (21) supports the end of the eccentric shaft (12) through the first cushion block (22) and the ball (23). The eccentric shaft (12) drives the bevel-toothed cycloidal wheel (15) to move synchronously. The conical outer teeth of the bevel-toothed cycloidal wheel (15) are tightly meshed with the needle roller (3), and the tooth clearance between the bevel-toothed cycloidal wheel (15) and the needle roller (3) is elastically eliminated.

4. The zero backlash self-adjusting structure RV reducer according to claim 1, characterized in that: The nut (27) locks and pre-compresses the second butterfly-shaped spring piece (26), and the outer teeth of the bevel-toothed planetary gear (17) are tightly meshed with the outer teeth of the input bevel gear (18) under the elastic force of the second butterfly-shaped spring piece (26), thereby elastically eliminating the tooth clearance between the bevel-toothed planetary gear (17) and the input bevel gear (18).

5. The zero backlash self-adjusting structure RV reducer according to claim 1, characterized in that: Mounting bearings (6) are respectively arranged between the outer circle of the output shaft (4), the outer circle of the output end cover (5) and the inner circle of the pinion housing (1), and the mounting bearing (6) is one of a tapered roller bearing, an angular contact ball bearing or a deep groove ball bearing; a skeleton sealing ring (7) is arranged between the output shaft (4) and the pinion housing (1), and the skeleton sealing ring (7) is located on a side of the mounting bearing (6) close to the mounting bearing (6) and away from the output end cover (5).

6. The zero backlash self-adjusting structure RV reducer according to claim 1, characterized in that: Each of the bevel-toothed cycloid wheels (15) is mounted on a corresponding cam on the eccentric shaft (12) via a plurality of double-row tapered rollers (16) arranged in a circumferential array, and the outer wall of the cam of the eccentric shaft (12) and the inner wall of the bevel-toothed cycloid wheel (15) respectively serve as the inner ring and outer ring of the double-row tapered rollers (16) for position limiting installation.

7. The zero backlash self-adjusting structure RV reducer according to claim 1, characterized in that: The two ends of the input shaft (8) are respectively mounted on the output shaft (4) and the output end cover (5) via first tapered roller bearings (9); the outer rings of the two first tapered roller bearings (9) are respectively fixed via hole retaining rings (10); and the two hole retaining rings (10) are located on the sides of the two first tapered roller bearings (9) that are away from each other; a limiting step (11) is provided on the outer wall of the input shaft (8), and the inner ring of the first tapered roller bearing (9) is clamped on the limiting step (11).

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