A reducer with high rigidity and long service life

Abstract

The present invention provides a high-rigidity, long-life reducer, relating to the technical field of reducers. The RV reducer comprises a pinion housing and a main bearing. The pinion housing is provided with a first mating portion at the main bearing mounting location; the outer ring of the main bearing is provided with a second mating portion at the lower end surface of its raceway, which is configured to mate with the first mating portion. Based on the technical solution of the present invention, by modifying the structure of the main bearing outer ring and the main bearing mounting location on the pinion housing, the connection strength between the main bearing and the pinion housing is enhanced, and the contact force area between the main bearing outer ring and the inner wall of the pinion housing is increased. This helps reduce deformation of the main bearing outer ring, thereby effectively enhancing the load-bearing capacity of the main bearing and improving the bending moment stiffness of the entire machine.

Description

Technical Field

[0001] The present invention relates to the technical field of reducers, and in particular to a reducer with high rigidity and long service life. Background Art

[0002] The RV reducer is a new type of cycloid planetary transmission consisting of a primary planetary gear drive and a secondary cycloid pinwheel drive. It is primarily used in the joints of industrial robots, requiring high transmission accuracy, low backlash, high rigidity, strong impact resistance, compact structure, and high transmission efficiency. As the application scope of industrial robots expands, higher requirements are placed on the bending moment stiffness and lifespan of RV reducers.

[0003] The existing RV reducer structure includes components such as a pinion housing, planetary carrier, eccentric shaft, planetary gears, main bearing, rigid plate, and cycloid gear. For existing RV reducers, bending moment stiffness is primarily provided by the main bearing. The main bearing's support stiffness is related to its raceway design dimensions, main bearing mounting method, and main bearing axial preload.

[0004] The existing patent with authorization announcement number CN107575469B provides a new structural design of the main bearing, which converts the original angular contact ball bearing into a tapered roller bearing and controls the parameters therein to improve the bending moment stiffness and life.

[0005] Separately, a prior patent application with application publication number CN111881529A provides a method for adjusting the design parameters of angular contact ball bearings based on a force analysis of the RV reducer's main bearing. Both of these prior patents optimize the bearing raceway dimensions within spatial constraints, but fail to optimize other structural parameters.

[0006] However, in reality, under certain working conditions and space, slight changes in the raceway design dimensions and the axial preload of the main bearing have a great impact on the life of the main bearing. On the basis of ensuring the life, the range of improving the stiffness by optimizing the design of the raceway parameters and the axial preload of the main bearing is relatively small. Therefore, it is necessary to improve the bending moment stiffness from other structural designs and at the same time extend the life of the entire machine. Summary of the Invention

[0007] The present invention provides a high-rigidity and long-life reducer, which is used to solve the problem of the contradiction between the main bearing installation space of the existing RV reducer and the bending moment stiffness of the whole machine, while ensuring the service life of the whole machine and improving its bending moment stiffness.

[0008] The present invention provides a high-rigidity and long-life reducer, comprising a pinion housing and a main bearing, wherein the pinion housing is provided with a first mating portion at the installation position of the main bearing; the outer ring of the main bearing is provided with a second mating portion for mating with the first mating portion at the position of the lower end face of its raceway.

[0009] In one embodiment, the first mating portion is an annular groove extending along the inner circumference of the pinion housing; the second mating portion is embedded in the first mating portion during installation. In this embodiment, the main bearing mates with the annular groove on the pinion housing via the second mating portion, enhancing the connection strength between the main bearing and the pinion housing, increasing the contact area between the main bearing outer ring and the inner wall of the pinion housing, and helping to reduce deformation of the main bearing outer ring, thereby enhancing the load-bearing capacity of the main bearing and improving the bending moment stiffness of the entire machine.

[0010] In one embodiment, the second fitting portion is an annular groove extending along the circumferential direction of the inner side of the outer ring of the main bearing; and the first fitting portion is embedded in the second fitting portion during installation.

[0011] In one embodiment, the second matching portion is a wedge-shaped structure or a conical structure.

[0012] In one embodiment, the distance between the groove of the first matching portion and the bottom of the needle hole on the needle housing is 2 mm to 3 mm. This embodiment ensures that the processing of the needle hole in the needle housing is not affected and that the structural strength of the needle hole meets the load operation requirements.

[0013] In one embodiment, the first mating portions are provided on the upper and lower sides of the pinion housing; the main bearings are arranged in pairs, with the second mating portions on each main bearing mating with the first mating portions on the corresponding side. This embodiment allows both main bearings to be subjected to force simultaneously, further evenly distributing the force and improving the bending moment stiffness of the RV reducer.

[0014] In one embodiment, a needle roller is embedded in the needle tooth hole on the needle tooth housing, and the upper and lower ends of the needle roller respectively abut against the main bearings arranged in pairs.

[0015] In one embodiment, the main bearing is a thin-walled bearing. Through this embodiment, the RV reducer structure can be made more compact.

[0016] In one embodiment, a transition fit or slight interference fit is employed between the main bearing and the pinion housing. This embodiment, due to structural changes in the main bearing's outer ring and the main bearing's mounting position on the pinion housing, allows the main bearing to be installed using a transition fit to achieve the same moment stiffness as a conventional interference fit installation. This significantly reduces installation difficulty, improves installation efficiency, and significantly enhances overall reliability.

[0017] Compared with the prior art, the advantages of the present invention are:

[0018] (1) By changing the structure of the main bearing outer ring and the main bearing installation position on the pinion housing, the connection strength between the main bearing and the pinion housing is enhanced, and the contact force area between the main bearing outer ring and the inner wall of the pinion housing is increased, which helps to reduce the deformation of the main bearing outer ring, thereby effectively enhancing the load-bearing capacity of the main bearing and improving the bending moment stiffness of the entire machine;

[0019] (2) The cooperation between the second matching portion on the main bearing and the first matching portion on the pinion housing can effectively reduce the overturning angle of the outer ring of the main bearing under heavy load, thereby ensuring the bending moment stiffness of the entire machine during load-bearing operation and improving the stability of the entire machine transmission;

[0020] (3) Through the cooperation of the second matching part on the main bearing and the first matching part on the pinion housing, the large end face and the inner end face of the outer ring of the main bearing are in contact with the pinion housing at the same time. When the whole machine is subjected to impact load, the two contact surfaces of inner and outer sizes work together to evenly distribute the force, which can reduce the impact damage to the main bearing and internal mechanisms, thereby further improving the service life of the whole machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0022] Figure 1 This is a schematic diagram of the overall structure of an RV reducer in one embodiment of the present invention;

[0023] Figure 2 2 is a schematic structural diagram of a pin gear housing according to an embodiment of the present invention;

[0024] Figure 3 Schematic diagram of the structure of the main bearing outer ring in one embodiment of the present invention.

[0025] Reference numerals:

[0026] 1. Pin gear housing; 101. First mating part; 102. Pin gear hole; 2. Eccentric shaft; 3. Planet carrier; 4. Rigid disk; 5. Main bearing; 51. Main bearing outer ring; 511. Second mating part; 512. Large end face of the main bearing outer ring; 513. Inner wedge-shaped end face; 6. Cycloid wheel; 7. Roller bearing; 8. Needle roller; 9. Planetary gear. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings.

[0028] See attached Figure 1The present invention provides a high-rigidity, long-life reducer comprising a pinion housing 1, within which at least two eccentric shafts 2 are evenly distributed around the circumference. A planetary carrier 3 is disposed within the pinion housing 1, adjacent to the upper ends of the eccentric shafts 2, while a rigid disk 4 is disposed adjacent to the lower ends of the eccentric shafts 2. Both the planetary carrier 3 and the rigid disk 4 are rotationally coupled to the eccentric shafts 2 via tapered roller bearings. A planetary gear 9 is fixedly mounted on the end of the eccentric shaft 2 closest to the planetary carrier 3.

[0029] Main bearings 5 ​​are installed between the inner wall of the pinion housing 1 and the outer wall of the planetary carrier 3, and between the inner wall of the pinion housing 1 and the outer wall of the rigid plate 4. The two main bearings 5 ​​are paired and can be installed back-to-back. The rigid plate 4 and the planetary carrier 3 respectively act as axial limiters for the main bearings 5 ​​on the corresponding side. It should be noted that to make the RV reducer more compact, thin-walled bearings are generally used for the main bearings 5, but tapered roller bearings or other commonly used bearings are also possible.

[0030] A cycloid wheel 6 is also sleeved on the outside of the eccentric shaft 2. A roller bearing 7 can be set between the cycloid wheel 6 and the eccentric shaft 2. The cycloid wheel 6 can be set in pairs up and down. The cycloid wheel 6 and the needle tooth hole 102 on the inner side of the needle tooth housing 1 can form a rotational fit through a needle roller 8, and when installed, the upper and lower ends of the needle roller 8 respectively abut against the two main bearings 5.

[0031] Combined with attachment Figure 2-3 The pinion housing 1 has a first mating portion 101 formed at the main bearing mounting location. Correspondingly, the main bearing outer ring 51 has a second mating portion 511 formed on the lower end surface of its raceway. During installation, the second mating portion 511 on the main bearing 5 forms a nested fit with the first mating portion 101 on the pinion housing 1.

[0032] In this embodiment, the above-mentioned first matching part 101 can be set as a groove-type groove structure, which is an annular groove extending along the inner circumferential direction of the needle tooth housing 1; correspondingly, the second matching part 511 is set as a protruding structure so as to be embedded in the groove of the first matching part 101.

[0033] In this embodiment, due to the presence of the annular groove on the needle tooth housing 1, in order to ensure that the processing of the needle tooth hole 102 in the needle tooth housing 1 is not affected and that the structural strength of the needle tooth hole 102 meets the load operation requirements, the distance between the groove surface of the first mating part 101 and the bottom of the needle tooth hole 102 should meet the requirements of 2mm to 3mm or larger, and the specific design can be optimized according to the main bearing installation position size and strength requirements.

[0034] At the same time, in this embodiment, the second matching portion 511 can be configured as a wedge-shaped structure, and the length and angle of the wedge-shaped structure can be optimized according to the size of its installation position, without specific limitation.

[0035] During actual operation, the second matching portion 511 of the wedge-shaped structure is embedded in the groove of the first matching portion 101, so that the large end face 512 of the main bearing outer ring and the inner wedge-shaped end face 513 are in contact with the pinion housing 1 and bear the force together. When the entire machine is subjected to an impact load, the inner and outer contact surfaces work together to evenly distribute the force. Therefore, the second matching portion 511 on the main bearing 5 is designed to be a wedge-shaped structure, which can increase the contact force area between the main bearing outer ring 51 and the inner wall of the pinion housing 1, and evenly distribute the force, thereby reducing the influence of the external load on the deformation of the main bearing outer ring 51, helping to reduce the deformation of the main bearing outer ring 51, thereby enhancing the load-bearing capacity of the main bearing 5 and improving the bending moment stiffness of the entire machine.

[0036] It should be noted that in order to ensure that the main bearing 5 has sufficient bending moment stiffness, its outer ring is generally installed on the main bearing mounting position of the pinion housing 1 through radial interference fit. The radial interference fit of thin-walled bearings requires very high installation accuracy. In this embodiment, the new structural outer ring of the main bearing 5 has a greatly increased bearing mating surface and is designed with a wedge-shaped structure to perform high-precision fit with the bearing mounting position of the pinion housing 1, which has the effect of fixing and strengthening the fit. Therefore, the main bearing outer ring 51 with a new structure in this embodiment is adopted, and a transition fit or a small interference fit is used to achieve the bending moment stiffness after the traditional structure interference fit installation, which greatly reduces the installation difficulty, improves the installation efficiency, and significantly improves the reliability of the whole machine.

[0037] In another embodiment, the second matching portion 511 may be configured as a conical structure, or the inclined surface of the second matching portion 511 may be further configured as a serrated structure, and a corresponding serrated groove may be formed on the inclined surface of the first matching portion 101 to match it. That is, it is only necessary to ensure that the first matching portion 101 can form an embedded fit with the second matching portion 511. The specific reinforcement structure is also not limited and can be optimized according to actual needs.

[0038] At the same time, in another embodiment, the second matching portion 511 can also be set as an annular groove extending along the inner circumferential direction of the outer ring of the main bearing 5; in this case, it is only necessary to set the first matching portion 101 as a protruding structure that can be embedded in the second matching portion 511.

[0039] In the description of the present invention, it should be understood that terms such as "upper", "lower", "bottom", "top", "front", "back", "inside", "outside", "left", and "right" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0040] While the present invention has been described with reference to preferred embodiments, various modifications may be made and equivalent components may be substituted without departing from the scope of the present invention. In particular, the various technical features described in the various embodiments may be combined in any manner, provided no structural conflicts exist. The present invention is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A high-rigidity and high-life speed reducer, comprising a pinion housing (1) and a main bearing (5), characterized in that: The pinion housing (1) is provided with a first matching portion (101) at the main bearing installation position; the outer ring of the main bearing (5) is provided with a second matching portion (511) for matching with the first matching portion (101) at the position of the lower end surface of the raceway thereof; at least two eccentric shafts are provided on the inner side of the pinion housing in a uniformly distributed manner, wherein: The first matching portion (101) is an annular groove extending along the inner circumferential direction of the needle gear housing (1); the second matching portion (511) is embedded in the first matching portion (101) during installation; or The second matching portion (511) is an annular groove extending along the inner circumferential direction of the outer ring of the main bearing (5); the first matching portion (101) is embedded in the second matching portion (511) during installation.

2. A high-rigidity and long-life reducer according to claim 1, characterized in that: The second matching portion (511) is a wedge-shaped structure or a conical structure.

3. The high-rigidity and long-life reducer according to claim 1, characterized in that: The distance between the groove of the first matching portion (101) and the bottom of the needle tooth hole (102) on the needle tooth housing (1) is 2 mm to 3 mm.

4. A high-rigidity and long-life reducer according to claim 3, characterized in that: The first matching portions (101) are respectively arranged on the upper and lower sides of the pinion housing (1); the main bearings (5) are arranged in pairs, and the two main bearings (5) respectively match with the first matching portions (101) on the corresponding sides through the second matching portions (511) thereon.

5. A high-rigidity and long-life reducer according to claim 4, characterized in that: A needle roller (8) is embedded in the needle tooth hole (102) on the needle tooth housing (1), and the upper and lower ends of the needle roller (8) respectively abut against the main bearings (5) arranged in pairs.

6. A high-rigidity and long-life reducer according to any one of claims 1 to 5, characterized in that: The main bearing (5) adopts a thin-walled bearing.

7. A high-rigidity and long-life reducer according to any one of claims 1 to 5, characterized in that: A transition fit or a small interference fit is adopted between the main bearing (5) and the pinion housing (1).

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