Large-transmission-ratio precision transmission device for robot joints

Abstract

The utility model relates to the field of transmission devices, in particular to a robot joint large-transmission-ratio precision transmission device which comprises a transmission system part and a shell part. The transmission system part comprises a gear ring seat assembly, a planet carrier assembly, a plurality of planet wheel parts, a gear ring output gear fixed to the gear ring seat assembly, a movable gear ring, a first variable-thickness gear fixedly connected to the planet carrier assembly, a fixed gear meshed with the first variable-thickness gear, and a second variable-thickness gear meshed with the fixed gear. A first elastic assembly making contact with the shaft end of the sun gear shaft is arranged on the first variable-thickness gear, a second elastic assembly making contact with the shell B is arranged on the second variable-thickness gear, and a third elastic assembly is arranged between the gear ring base assembly and the movable gear ring. According to the utility model, the backlash of the gear pair is greatly reduced and the transmission precision is ensured through the backlash elimination application of the three thickened gears; different transmission ratios can be obtained by changing the tooth number ratio of the gear ring output gear to the second variable-thickness gear, and a large transmission ratio coverage range is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of transmission devices, and particularly to a high transmission ratio precision transmission device for a robot joint. Background Art

[0002] The robot joint is one of the core components of a robot. In order to achieve a smaller spatial layout size, obtain a larger transmission ratio, and at the same time achieve precise transmission, the current robot joint transmission mainly relies on RV reducers and harmonic reducers for transmission. The RV reducer is a two-stage reduction device composed of a planetary reducer and a cycloidal reducer in series, and the harmonic reducer is a reduction device based on the principle of less tooth difference transmission. However, the above two reduction devices are relatively expensive and have a relatively high processing difficulty. In particular, the RV reducer highly depends on imports, which further increases the use cost. At the same time, although domestic RV reducers have made remarkable progress in technical breakthroughs and industrialization, large-scale manufacturing is still difficult. Moreover, due to structural limitations, the reduction ratio span of a single model of RV reducer and harmonic reducer is relatively large, which increases the selection difficulty. Summary of the Invention

[0003] In order to solve the above problems, the utility model provides a high transmission ratio precision transmission device for a robot joint.

[0004] A high transmission ratio precision transmission device for a robot joint includes a transmission system part and a housing part, wherein:

[0005] The housing part includes a base and a housing assembly;

[0006] The transmission system part includes a ring gear seat assembly rotatably installed in the housing assembly, a planet carrier assembly rotatably installed in the corresponding shaft hole on the ring gear seat assembly, a plurality of planet wheel parts rotatably installed on the planet carrier assembly and evenly arranged, a sun gear shaft meshing with all the planet wheel parts, a ring gear output gear fixed on the ring gear seat assembly, a moving ring gear meshing with the gear on the planet wheel part, a first variable thickness gear fixedly connected to the planet carrier assembly, a fixed gear meshing with the first variable thickness gear, and a second variable thickness gear meshing with the fixed gear and the ring gear output gear;

[0007] A first elastic component in contact with the shaft end of the sun gear shaft is provided on the first variable thickness gear, a second elastic component in contact with the housing B of the housing assembly is provided on the second variable thickness gear, and a third elastic component is provided between the ring gear seat assembly and the moving ring gear.

[0008] Further, the housing assembly includes a housing A, a housing B, and a housing C connected by housing fastening screws.

[0009] Further, the fixed gear is fixedly connected to a fixed shaft by a large gear fastening screw. One side of the fixed shaft is fixedly connected to the base, and the fixed shaft is connected to housing A through a main bearing.

[0010] Further, the first elastic component includes a first spring disposed inside the first variable-thickness gear and a first compression rod inserted into the first spring and cooperating with the first spring. Under the action of the first spring, the first compression rod axially contacts the sun gear shaft through a first steel ball.

[0011] Further, the second elastic component includes a second spring installed inside the second variable-thickness gear and a second compression rod inserted into the second spring and fitting with the end face of the second spring. An internal hexagonal set screw is provided on housing B of the housing assembly. Under the action of the second spring, the second compression rod contacts the internal hexagonal set screw through a second steel ball.

[0012] Further, the third elastic component includes a third spring disposed between the ring gear seat assembly and the moving ring gear.

[0013] Further, the internal teeth on the moving ring gear mesh with the teeth of the gears on the planetary gear part, and the meshing teeth are variable-thickness teeth.

[0014] Further, there are several sliders filled between the moving ring gear and the ring gear seat assembly, so that the moving ring gear can move axially while restricting its rotation together with the ring gear seat assembly.

[0015] Further, the second variable-thickness gear is installed in the housing assembly through an idle wheel bearing.

[0016] As another improvement of the present utility model, the planetary gear part is any one of a double planetary gear shaft assembly and a single planetary gear. The double planetary gear shaft assembly includes a double planetary large gear and a double planetary small gear.

[0017] The beneficial effects of the present utility model are as follows: By applying the clearance elimination of three variable-thickness gears, the side clearance of the gear pair is greatly reduced, ensuring the transmission accuracy; By changing the tooth number ratio of the ring gear output gear and the second variable-thickness gear, different transmission ratios can be obtained, realizing a large transmission ratio coverage range. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present utility model will be further described below with reference to the drawings and embodiments.

[0019] Figure 1 is the transmission principle of the present utility model Figure 1 ;

[0020] Figure 2 is the transmission principle of the present utility model Figure 2 ;

[0021] Figure 3 Device assembly of the present utility model Figure 1 ;

[0022] Figure 4 Device assembly of the present utility model Figure 2 ;

[0023] Figure 5 For the present utility model Figure 4 Schematic diagram of a partially enlarged structure;

[0024] Figure 6 Schematic diagram of the structure of the double planetary gear shaft assembly of the present utility model;

[0025] Figure 7 Schematic diagram of the structure of the moving gear ring, slider and gear ring seat assembly of the present utility model;

[0026] Figure 8 Schematic diagram of the structure of the second variable-thickness gear of the present utility model;

[0027] Figure 9 Example effect of the present utility model when applied to a one-axis joint Figure 1 ;

[0028] Figure 10 Example effect of the present utility model when applied to a one-axis joint Figure 2 ;

[0029] Figure 11 Schematic diagram of the structure of the variable-thickness gear of the present utility model Figure 1 ;

[0030] Figure 12 Schematic diagram of the structure of the variable-thickness gear of the present utility model Figure 2 ;

[0031] Figure 13 Principle of another embodiment of the present utility model Figure 1 ;

[0032] Figure 14 Principle of another embodiment of the present utility model Figure 2 ;

[0033] Reference Numerals: 1, double planetary gear shaft assembly; 1b, large double planetary gear; 1a, small double planetary gear; 2, planetary gear needle roller bearing; 3, planetary gear thrust needle roller bearing; 4, planet carrier assembly; 5, planet carrier needle roller bearing; 6, ring gear seat assembly; 6a, upper cover of ring gear seat; 6b, lower cover of ring gear seat; 7, moving ring gear; 8, third spring; 9, slider; 10, ring gear output gear; 11, ring gear output gear screw; 12, angular contact bearing; 13, first variable-thickness gear; 14, planet carrier roller bearing; 15, first spring; 16, first compression rod; 17, first steel ball; 18, sun gear shaft; 19, motor; 20, fixed shaft; 21, main bearing; 22, large gear fastening screw; 23, fixed gear; 24, second variable-thickness gear; 24a, second variable-thickness gear shaft; 24b, intermediate idler gear; 25, idler gear bearing; 26, second spring; 27, second compression rod; 28, second steel ball; 29, hexagon socket set screw; 30, base; 31, housing A; 32, housing B; 33, housing C. Detailed Implementation Manner

[0034] In order to make the technical means, creative features, achieved purposes and effects realized by the present utility model easy to understand, the present utility model will be further described below.

[0035] Embodiment 1:

[0036] As Figures 1 to 12 shown, a high transmission ratio precision transmission device for a robot joint includes a transmission system part and a housing part, wherein:

[0037] The housing part includes a base 30 and a housing assembly, and the housing assembly includes a housing A 31, a housing B 32 and a housing C 33 connected by housing fastening screws.

[0038] As Figures 3 to 5 shown, the transmission system part includes a ring gear seat assembly 6 rotatably installed in the housing assembly, a planet carrier assembly 4 installed on corresponding shaft holes of the ring gear seat assembly 6 through planet carrier needle roller bearings 5 on both sides, a plurality of planetary gear parts evenly arranged on the planet carrier assembly 4 through two planetary gear needle roller bearings 2 and a planetary gear thrust needle roller bearing 3, a sun gear shaft 18 meshing with all the planetary gear parts, a ring gear output gear 10 fastened to the ring gear seat assembly 6 by ring gear output gear screws 11, a moving ring gear 7 meshing with the gears on the planetary gear parts, a first variable-thickness gear 13 fixedly connected to the planet carrier assembly 4, a fixed gear 23 meshing with the first variable-thickness gear 13, and a second variable-thickness gear 24 meshing with the fixed gear 23 and the ring gear output gear 10.

[0039] As Figure 5 shown, the ring gear seat assembly 6 is installed in the housing assembly through a pair of angular contact bearings 12;

[0040] A first elastic component that contacts the end of the sun gear shaft 18 is provided on the first thickened gear 13, a second elastic component that contacts the housing B32 of the housing assembly is provided on the second thickened gear 24, and a third elastic component is provided between the ring gear seat assembly 6 and the moving ring gear 7.

[0041] Specifically, the sun gear shaft 18 is connected with a motor 19 in an interference fit manner.

[0042] In this embodiment, the planetary gear part adopts a double-row planetary gear shaft assembly 1. The double-row planetary gear shaft assembly 1 includes a double-row planetary pinion 1a and a double-row planetary gear 1b, and their gear teeth numbers are Zc and Zd respectively; the gear teeth number on the moving ring gear 7 is Zb; the gear teeth number on the ring gear output gear 10 is Z2; the gear teeth number of the first thickened gear 13 is Z1; the gear teeth number of the sun gear shaft 18 is Za; the gear teeth number of the fixed gear 23 is Z3; the second thickened gear 24 is composed of a second thickened gear shaft 24a and an intermediate idler gear 24b, and their gear teeth numbers are Z5 and Z4 respectively. By changing the tooth number ratio between the ring gear output gear 10 and the second thickened gear 24, the present utility model can obtain different transmission ratios and achieve a large transmission ratio coverage range.

[0043] As Figure 1 shown, according to the gear meshing relationship of the epicyclic gear train, when the power enters from Za and is output from Z3, its transmission ratio:

[0044]

[0045] Among them,

[0046]

[0047] When obtaining a suitable tooth number ratio, a large transmission ratio value can be obtained.

[0048] For example: when Za = 21, Zb = 90, Zc = 26, Zd = 43, Z1 = 17, Z2 = 47, Z3 = 144, Z4 = 47, Z5 = 17, the calculated transmission ratio is 128.5. At the same time, according to the actual space size, the K value or Z1 - Z5 can be appropriately adjusted, and it is easy to obtain different transmission ratios to achieve a wide range of transmission ratio coverage.

[0049] The present utility model realizes high reduction ratio transmission through the combination of the closed double-row planetary gear shaft assembly 1 and the thickened gear structure design.

[0050] As Figure 4 shown, the fixed gear 23 is fixedly connected with a fixed shaft 20 through a large gear fastening screw 22. One side of the fixed shaft 20 is fixedly connected with the base 30, and the fixed shaft 20 is connected with the housing A31 through a main bearing 21.

[0051] As Figure 5 shown, the first elastic component includes a first spring 15 disposed inside the first variable-thickness gear 13 and a first compression rod 16 inserted into and cooperating with the first spring 15. Under the action of the first spring 15, the first compression rod 16 axially contacts the sun gear shaft 18 through a first steel ball 17.

[0052] The sun gear shaft 18 of the present utility model forces the first variable-thickness gear 13 to have a downward movement tendency under the action of the first spring 15 through the first steel ball 17 and the first compression rod 16. At the same time, the first variable-thickness gear 13 is fixedly connected to the planet carrier assembly 4 by an interference fit, so the double planetary gear shaft assembly 1 is also driven to move downward through the planet carrier assembly 4. The first variable-thickness gear 13 of the present utility model and the fixed gear 23 are also a pair of meshing variable-thickness gears, and the side clearance is eliminated during meshing under the action of the first spring 15.

[0053] As Figure 3 shown, the second elastic component includes a second spring 26 installed inside the second variable-thickness gear 24 and a second compression rod 27 inserted into the second spring 26 and fitting with the end face of the second spring 26. An internal hexagon set screw 29 is provided on the housing B32 of the housing assembly. Under the action of the second spring 26, the second compression rod 27 contacts the internal hexagon set screw 29 through a second steel ball 28. The second variable-thickness gear 24 is composed of a second variable-thickness gear shaft 24a and an intermediate idler gear 24b. The second variable-thickness gear shaft 24a and the fixed gear 23 are a pair of meshing variable-thickness gears, and the side clearance is eliminated during meshing under the action of the second spring 26, the second compression rod 27, the second steel ball 28, and the internal hexagon set screw 29; that is, a backlash elimination structure is adopted at the end of the transmission device, effectively reducing the gear meshing side clearance and reducing the backlash.

[0054] Specifically, the internal hexagon set screw 29 is screwed into the corresponding threaded hole of the housing B32 through an external thread.

[0055] As Figure 5 shown, the third elastic component includes a third spring 8 disposed between the ring gear seat assembly 6 and the moving ring gear 7.

[0056] The internal teeth on the moving ring gear 7 mesh with the teeth of the gears on the planet gear part, and the meshing teeth are variable-thickness teeth. The moving ring gear 7 and the double planetary pinion 1a are a pair of meshing variable-thickness gears, and the side clearance is eliminated during meshing through the first spring 15.

[0057] Furthermore, there are several sliders 9 filled between the moving ring gear 7 and the ring gear seat assembly 6, so that the moving ring gear 7 can move axially while restricting its rotation together with the ring gear seat assembly 6.

[0058] The second thickened gear 24 is mounted in the housing assembly through an idle gear bearing 25.

[0059] Specifically, as Figure 5 and Figure 7 shown, the moving gear ring 7 and the third spring 8 are mounted in a groove at the bottom of the gear ring seat assembly 6. One end face of the third spring 8 abuts against the bottom end face of the gear ring seat assembly 6, and the other end face of the third spring 8 abuts against the end face of the moving gear ring 7. The gear ring seat assembly 6 includes an upper cover 6a of the gear ring seat and a lower cover 6b of the gear ring seat; a plurality of outer arc-shaped grooves are provided on the outer cylindrical surface of the moving gear ring 7, and inner arc-shaped grooves corresponding to the positions of the outer arc-shaped grooves are provided on the inner wall of the lower cover 6b of the gear ring seat assembly 6, and the slider 9 is located between the corresponding outer arc-shaped groove and the inner arc-shaped groove.

[0060] As Figure 5 shown, one end of the first thickened gear 13 is mounted on the housing A31 through a planet carrier roller bearing 14, and the other end of the first thickened gear 13 is mounted on the planet carrier assembly 4 in an interference fit manner.

[0061] Embodiment 2:

[0062] As Figure 13 and Figure 14 shown, as another simple deformation application of the present invention, on the basis of Embodiment 1, the double planetary gear shaft assembly 1 of the planetary gear part is replaced with a single planetary gear, and the rest of the structure is the same as that of Embodiment 1. After the motor 19 drives the sun gear shaft 18 to rotate, it drives the single planetary gear to rotate around the moving gear ring 7, and the rest of the working process refers to Embodiment 1.

[0063] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A robot joint high transmission ratio precision transmission device, characterized in that: It includes a transmission system part and a housing part, wherein: The housing portion comprises a base (30) and a housing assembly; The transmission system comprises a ring gear seat assembly (6) rotatably mounted in a housing assembly, a planetary carrier assembly (4) rotatably mounted in a corresponding shaft hole on the ring gear seat assembly (6), a plurality of planetary gear parts rotatably mounted on the planetary carrier assembly (4) and evenly arranged, a sun gear shaft (18) meshed with the planetary gear parts, a ring gear output gear (10) fixed on the ring gear seat assembly (6), a moving ring gear (7) meshed with the gears on the planetary gear parts, a first thickened gear (13) fixedly connected to the planetary carrier assembly (4), a fixed gear (23) meshed with the first thickened gear (13), and a second thickened gear (24) meshed with the fixed gear (23) and the ring gear output gear (10); A first elastic component in contact with the shaft end of the sun gear shaft (18) is provided on the first thickened gear (13), a second elastic component in contact with the housing component is provided on the second thickened gear (24), and a third elastic component is provided between the gear ring seat component (6) and the movable gear ring (7).

2. A robot joint large transmission ratio precision transmission device according to claim 1, characterized in that: The housing assembly comprises a housing A (31), a housing B (32) and a housing C (33) connected by housing fastening screws.

3. A robot joint large transmission ratio precision transmission device according to claim 2, characterized in that: The fixed gear (23) is fixedly connected to the fixed shaft (20) via a large gear fastening screw (22); one side of the fixed shaft (20) is fixedly connected to the base (30); and the fixed shaft (20) is connected to the housing A (31) via a main bearing (21).

4. A robot joint large transmission ratio precision transmission device according to claim 1, characterized in that: The first elastic component comprises a first spring (15) arranged inside the first thickened gear (13), and a first compression rod (16) inserted into the first spring (15) and matched with the first spring (15); under the action of the first spring (15), the first compression rod (16) is in axial contact with the sun gear shaft (18) through the first steel ball (17).

5. The robot joint large transmission ratio precision transmission device according to claim 2, characterized in that: The second elastic component comprises a second spring (26) installed inside the second thickening gear (24), a second compression rod (27) inserted into the second spring (26) and abutting against the end surface of the second spring (26), and a hexagonal screw (29) is provided on the housing B (32). Under the action of the second spring (26), the second compression rod (27) contacts the hexagonal screw (29) through the second steel ball (28).

6. The robot joint large transmission ratio precision transmission device according to claim 1, characterized in that: The third elastic component comprises a third spring (8) arranged between the gear ring seat component (6) and the movable gear ring (7).

7. The robot joint large transmission ratio precision transmission device according to claim 1, characterized in that: The internal teeth on the moving gear ring (7) mesh with the teeth of the gear on the planetary gear part, and the teeth meshing with each other are thickened teeth.

8. The robot joint high transmission ratio precision transmission device according to claim 1, characterized in that: A plurality of slide blocks (9) are provided between the movable gear ring (7) and the gear ring seat assembly (6), so that the movable gear ring (7) can move axially while limiting the movable gear ring (7) from rotating together with the gear ring seat assembly (6).

9. The robot joint large transmission ratio precision transmission device according to claim 1, characterized in that: The second thickened gear (24) is mounted in the housing assembly via an idler bearing (25).

10. A robot joint high transmission ratio precision transmission device according to any one of claims 1 to 9, characterized in that: The planetary gear part is any one of a double planetary gear shaft assembly (1) and a single planetary gear.

Images