CN115030990A

CN115030990A - Eccentric swing type reduction gear

Info

Publication number: CN115030990A
Application number: CN202210186676.9A
Authority: CN
Inventors: 阿部瞬; 大桥拓也
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2021-03-05
Filing date: 2022-02-28
Publication date: 2022-09-09
Also published as: DE102022105024A1; DE102022105024B4; JP2022135326A

Abstract

An object of the present invention is to provide an eccentric oscillating type reduction gear capable of improving the lubricity of an eccentric body bearing. An eccentric oscillation type reduction gear (100) is provided with: an outer gear; an eccentric body shaft (12) for eccentrically oscillating the external gear; and an eccentric body bearing (30) disposed between the external gear and the eccentric body shaft (12), wherein the axial movement of the eccentric body bearing (30) is restricted by a pressing portion (40), and the pressing portion (40) has a cylindrical portion (402) extending in the axial direction and a flange portion (404) extending in the radial direction of the cylindrical portion (402).

Description

Eccentric swing type reduction gear

The present application claims priority based on japanese patent application No. 2021-035065, filed on 3/5/2021. The entire contents of this Japanese application are incorporated by reference into this specification.

Technical Field

The present invention relates to an eccentric oscillating type reduction gear.

Background

An eccentric oscillating type reduction gear device having an eccentric body bearing is known. The present applicant discloses, in patent document 1, an oscillating internally meshing planetary gear device having an external gear that internally meshes with an internal gear, and one of the external gear and the internal gear is oscillated and rotated by an eccentric body formed on an eccentric body shaft. The gear device includes an eccentric body shaft bearing for supporting an eccentric body shaft.

Patent document 1: japanese laid-open patent publication No. 2007-285396

The present inventors have studied an eccentric oscillating type reduction gear, and as a result, have obtained the following findings.

In order to ensure the reliability of the eccentric body bearing disposed between the external gear and the eccentric body shaft of the reduction gear, it is important to stably supply a lubricant to the eccentric body bearing to improve the lubricity. However, the reduction gear of patent document 1 does not sufficiently cope with these points of view, and there is still room for improvement.

Disclosure of Invention

The present invention has been made in view of such circumstances, and an object thereof is to provide an eccentric oscillating type speed reducer capable of improving the lubricating property of an eccentric body bearing.

In order to solve the above problem, an eccentric oscillating type reduction gear device according to an embodiment of the present invention includes: an outer gear; an eccentric body shaft that eccentrically swings the external gear; and an eccentric body bearing disposed between the external gear and the eccentric body shaft, wherein axial movement of the eccentric body bearing is restricted by a pressing portion, and the pressing portion has a cylindrical portion extending in the axial direction and a flange portion extending in the radial direction of the cylindrical portion.

According to the present invention, an eccentric oscillating type reduction gear capable of improving the lubricity of an eccentric body bearing is provided.

Drawings

Fig. 1 is a side sectional view showing an eccentric rocking type reduction gear according to an embodiment.

Fig. 2 is a sectional view of the eccentric oscillation type reduction gear of fig. 1 taken along the line a-a.

Fig. 3 is an enlarged sectional view illustrating the periphery of the eccentric body shaft of fig. 1.

Fig. 4 is an enlarged sectional view showing the periphery of the pressing portion of fig. 3.

Fig. 5 is an enlarged sectional view showing the periphery of the pressing portion of fig. 3.

In the figure: 12-eccentric body shaft, 14-external gear, 30-eccentric body bearing, 40-pressing part, 124-concave part, 126-convex part, 128-eccentric part, 129, 130, 131-outer periphery, 304-retainer, 306-annular part, 308-outer periphery, 335-outer periphery, 402-cylindrical part, 404-flange part, 406-abutment part, 407, 408-outer periphery, W1, W2, W3-axial dimension, 100-eccentric oscillation type reduction gear.

Detailed Description

Preferred embodiments of the present invention will be described below with reference to the drawings. In the embodiment and the modifications, the same or equivalent constituent elements and components are denoted by the same reference numerals, and overlapping description is appropriately omitted. In the drawings, the dimensions of the components are shown enlarged or reduced as appropriate for the convenience of understanding. In the drawings, some parts that are not important in the description of the embodiments are omitted.

Further, the terms including the numbers 1, 2, and the like are used to describe various constituent elements, but the terms are only used for the purpose of distinguishing one constituent element from other constituent elements, and the terms are not used to limit the constituent elements.

[ embodiment ]

Hereinafter, a structure of an eccentric rocking type reduction gear device 100 (hereinafter, may be referred to as "reduction gear device 100") according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a side sectional view schematically showing a reduction gear transmission 100 according to the present embodiment. Fig. 2 is a sectional view taken along line a-a of fig. 1. Fig. 3 is an enlarged sectional view showing the periphery of the eccentric body shaft 12. The purpose of the reduction gear transmission 100 is not limited, and in this example, the reduction gear transmission 100 may be used for joints of a multi-joint robot, for example.

Next, the overall structure of the reduction gear transmission 100 will be described. The reduction gear 100 mainly includes the eccentric body shaft 12, the external gear 14, the internal gear 16, the carriers 18, 20, the housing 22, the

main bearings

24, 26, the eccentric body bearing 30, the inner pin 32, the eccentric

body shaft bearings

33, 34, and the pressing part 40.

Hereinafter, a direction along the central axis La of the internal gear 16 is referred to as an "axial direction", and a circumferential direction and a radial direction of a circle centered on the central axis La are referred to as a "circumferential direction" and a "radial direction", respectively. For convenience, hereinafter, one side in the axial direction (right side in the drawing) is referred to as an input side, and the other side in the axial direction (left side in the drawing) is referred to as an opposite-to-input side. Such directional marks are not intended to limit the posture of use of the reduction gear transmission 100, and the reduction gear transmission 100 may be used in any posture.

The carriers 18, 20 include a 1 st carrier 18 disposed on the input-side opposite side of the external gear 14 and a 2 nd carrier 20 disposed on the input side of the external gear 14. The

main bearings

24 and 26 include a 1 st main bearing 24 disposed on the input-side opposite to the external gear 14 and a 2 nd main bearing 26 disposed on the input side of the external gear 14. The eccentric

body shaft bearings

33, 34 include a 1 st eccentric body shaft bearing 33 disposed on the input-side opposite to the external gear 14, and a 2 nd eccentric body shaft bearing 34 disposed on the input side of the external gear 14.

The reduction gear transmission 100 of the present embodiment is a center crank type reduction gear transmission in which the eccentric body shaft 12 and the central axis La of the internal gear 16 are disposed on the same axis. The reduction gear transmission 100 has a hollow portion H penetrating a central portion in the axial direction. The hollow portion H is provided to the eccentric body shaft 12.

The housing 22 constitutes a casing of the reduction gear transmission 100. The carriers 18, 20 are disposed inside the casing 22, and rotate relative to the casing 22. The eccentric body shaft 12 has a hollow cylindrical shape with a hollow portion H at the center. For example, a motor shaft is coupled to an input-side end of the eccentric body shaft 12 by a coupling such as a bolt.

The eccentric body shaft 12 has a plurality of eccentric portions 128, and the eccentric portions 128 function as eccentric bodies for oscillating the external gear 14. In this example, the eccentric body shaft 12 has two eccentric portions 128 that are shifted from each other by a phase difference of 180 °. Both ends of the eccentric body shaft 12 are supported by the wheel carriers 18 and 20 via eccentric

body shaft bearings

33 and 34. The number of the eccentric portions 128 is not limited to two, and may be one, three, or more.

As shown in fig. 3, the eccentric body shaft 12 has a recess 124 recessed inward in the radial direction at a position near the input-opposite side of the eccentric body bearing 30. The eccentric body shaft 12 has a convex portion 126 protruding radially outward at a position adjacent to the concave portion 124 on the opposite side of the eccentric body bearing 30. The concave portion 124 and the convex portion 126 are left to be described later. A lubricant G is sealed inside the housing 22 (particularly, in the vicinity of the eccentric body bearing 30).

The structure of the

eccentric body bearings

33, 34 is not limited. In this example, the 1 st eccentric body bearing 33 disposed on the input-side opposite side is a deep groove ball bearing in which the rolling elements 332 are balls (spheres). The rolling bodies 332 roll between the inner race 334 and the outer race 336. The 2 nd eccentric body shaft bearing 34 disposed on the input side is a roller bearing in which the rolling elements 342 are rollers (cylindrical bodies). The 2 nd eccentric body shaft bearing 34 does not have an inner ring and an outer ring, and the rolling elements 342 roll between the outer peripheral surface 132 of the eccentric body shaft 12 and the inner peripheral surface 202 of the 2 nd carrier 20.

In the present embodiment, the eccentric body bearing 30 includes a cylindrical roller-shaped rolling element 302 and a cage 304. A plurality of rolling elements 302 (for example, 38) are arranged at predetermined intervals around the eccentric portion 128. The cage 304 rotatably holds the plurality of rolling elements 302 at predetermined positions. The cage 304 has annular ring portions 306 provided on side portions of both ends in the axial direction of the rolling elements 302, and pocket portions (not shown) for accommodating the rolling elements 302. The eccentric body bearing 30 does not have an inner ring and an outer ring, and the rolling elements 302 roll between the outer peripheral surface of the eccentric portion 128 and the inner peripheral surface of the center hole 14c of the external gear 14. As shown in fig. 3, the pressing portion 40 restricts the eccentric body bearing 30 from moving toward the opposite-input side in the axial direction. The retainer ring 352 and the washer 354 restrict the eccentric body bearing 30 from moving toward the input side in the axial direction via the 2 nd eccentric body shaft bearing 34. The pressing portion 40 is left to be described later.

As shown in fig. 2, the external gear 14 is rotatably supported by the corresponding eccentric portion 128 via the eccentric body bearing 30. The external gear 14 is formed with a central hole 14c and a plurality of internal pin holes 14 h. The center hole 14c is a through hole provided in the center of the external gear 14. The plurality of inner pin holes 14h are through holes provided at positions offset from the center of the external gear 14. In the example of fig. 2, 10 inner pin holes 14h are arranged at intervals of 36 ° in the circumferential direction. The inner pin 32 is inserted through the inner pin hole 14 h. The teeth formed on the outer periphery of the external gear 14 rotate while meshing with the teeth of the internal gear 16, whereby the external gear 14 oscillates.

As shown in fig. 2, the internal gear 16 meshes with the external gear 14. The internal gear 16 of the present embodiment is composed of an internal gear main body integrated with the case 22, and an outer pin 16p (pin member) rotatably supported by the internal gear main body. The outer pins 16p constitute internal teeth of the internal gear 16. The number of internal teeth of the internal gear 16 (the number of the outer pins 16 p) is slightly larger than the number of external teeth of the external gear 14 (in this example, there is only one more).

As shown in fig. 1, the 1 st carrier 18 and the 2 nd carrier 20 are rotatably supported by the casing 22 via

main bearings

24 and 26. The 1 st carrier 18 supports the eccentric body shaft 12 via the 1 st eccentric body shaft bearing 33. The 2 nd carrier 20 supports the eccentric body shaft 12 via the 2 nd eccentric body shaft bearing 34.

The 1 st carrier 18 and the 2 nd carrier 20 are coupled together via inner pins 32. The inner pin 32 axially penetrates the inner pin hole 14h of the external gear 14 at a position of the external gear 14 deviated in the radial direction from the axis center.

One of the carriers 18, 20 and the casing 22 functions as an output member that outputs rotational power to a driven device, and the other functions as a fixed member that is fixed to an external member for supporting the reduction gear transmission 100. In the present embodiment, the output member is the 1 st carrier 18 and the 2 nd carrier 20, and the fixed member is the casing 22.

In the example of fig. 2, 10 inner pins 32 are arranged at 36 ° intervals in the circumferential direction. In fig. 1, only one inner pin 32 is shown. The inner pin 32 is fixed to the 1 st carrier 18 on the opposite side to the input side and to the 2 nd carrier 20 on the input side. The inner pin 32 couples the 1 st and 2 nd wheel carriers 18, 20. In the example of fig. 1, the inner pin 32 is formed integrally with the 1 st carrier 18, and the input side is fixed to the 2 nd carrier 20 by a bolt B1. A sleeve 32s is provided on the outer periphery of the inner pin 32. The inner pin 32 is inserted into the inner pin hole 14h with a gap from the inner pin hole 14 h. The inner pin 32 abuts a part of the inner pin hole 14h via the sleeve 32 s. The inner pin 32 restricts the rotation of the outer gear 14 and allows only the oscillation thereof.

The

main bearings

24 and 26 are disposed between the 1 st carrier 18 and the casing 22 and between the 2 nd carrier 20 and the casing 22. The structure of the

main bearings

24 and 26 is not limited, and in this example, the

main bearings

24 and 26 are roller bearings in which the rolling bodies 24e and 26e are cylindrical rollers. In fig. 1, the cage holding the rolling elements 24e, 26e is omitted. The outer races of

main bearings

24, 26 are supported by housing 22. The inner race of the 1 st main bearing 24 is formed integrally with the carrier 18. The inner race of the 2 nd main bearing 26 is formed integrally with the carrier 20.

The housing 22 is a hollow cylindrical member that surrounds the wheel carriers 18, 20. As shown in fig. 1, an oil seal 28 that seals lubricant from the main bearing 24 is provided between the casing 22 and the 1 st wheel carrier 18.

Hereinafter, a characteristic structure of the present embodiment will be described.

The present inventors have studied a reduction gear transmission and as a result, have obtained the following findings.

In order to achieve reduction in size and weight of the reduction gear, it is necessary to reduce the size of the rolling elements of the eccentric body bearing disposed between the external gear and the eccentric body shaft. For example, when the reduction gear transmission 100 is applied to a joint of a robot hand or the like, it is preferable to increase the hollow diameter of the hollow portion H of the eccentric body shaft 12 in order to pass wiring or piping. In order to increase the hollow diameter without changing the overall size, it is conceivable to reduce the roller diameter of the rollers (rolling elements 302) of the eccentric body bearing 30. However, if the roller diameter is reduced, the life of the bearing tends to be shortened.

In order to ensure the bearing life while reducing the roller diameter, it is effective to improve the lubricity. In order to improve lubricity, it is conceivable to fill the inside of the reduction gear with a lubricant. At this time, the periphery of the eccentric body shaft 12 rotating at a high speed is filled with the lubricant, and the stirring resistance of the lubricant increases, resulting in an increase in loss. Further, when the amount of the lubricant filled is reduced, the lubricant is biased to the outer peripheral side by the centrifugal force during rotation, and the lubricant contributing to lubrication of the rolling elements 302 is reduced, which leads to a reduction in the life.

Accordingly, the present inventors have made extensive studies from the viewpoint of providing a lubricant storage space around the rolling elements 302. As a result, they found that: by pressing the rolling element 302 with a pressing portion having a predetermined shape, a lubricant storage space can be secured in the vicinity of the rolling element 302. With this configuration, the influence of the centrifugal force can be reduced while suppressing an increase in the stirring resistance of the lubricant. This will be specifically described below.

The pressing portion 40 is explained with reference to fig. 3 to 5. Fig. 4 and 5 are enlarged cross-sectional views showing the periphery (the range of the broken line E) of the pressing portion 40. Fig. 5 shows a state in which the eccentric body shaft 12 is rotated by 180 ° with respect to the state of fig. 4. The pressing part 40 is configured to reduce the escape of the lubricant G due to the centrifugal force by restricting the eccentric body bearing 30 from moving toward the opposite input side in the axial direction and securing a storage space for the lubricant G around the rolling elements 302.

As shown in fig. 3 to 5, the pressing portion 40 includes a cylindrical portion 402, a flange portion 404, and an abutting portion 406. The pressing portion 40 is a hollow annular member, and is made of metal or resin. The cylindrical portion 402, the flange portion 404, and the abutting portion 406 of the pressing portion 40 may be uniform in the circumferential direction and may not have holes, convex portions, concave portions, and the like, or may be non-uniform in the circumferential direction and may have holes, convex portions, concave portions, and the like in a part of the circumferential direction.

The cylindrical portion 402 is a cylindrical portion extending in the axial direction, and the outer diameter thereof may be constant or may vary in the axial direction. The flange portion 404 is a flange-like portion extending in the radial direction of the cylindrical portion 402. In this example, the flange portion 404 extends radially outward from the input-side end of the cylindrical portion 402. The outer shape of the flange portion 404 may be circular or non-circular when viewed in the axial direction. As shown in fig. 3 to 5, the flange portion 404 abuts on the opposite side of the input side of the annular portion 306 of the holder 304 of the eccentric body bearing 30.

The abutting portion 406 is a portion that restricts the axial movement of the pressing portion 40. In this example, the abutting portion 406 is provided on the opposite side (the input-opposite side) of the cylindrical portion 402 from the flange portion 404, and extends radially inward from the end portion of the cylindrical portion 402. The inner shape of the abutment portion 406 may be circular or non-circular when viewed in the axial direction. As shown in fig. 3 to 5, the abutment portion 406 is inserted into the axial gap between the protrusion 126 of the eccentric body shaft 12 and the inner ring 334 of the 1 st eccentric body shaft bearing 33. The abutment portion 406 abuts against the inner race 334 of the 1 st eccentric body shaft bearing 33.

As shown in fig. 3, the eccentric body shaft 12 has an outer peripheral surface 132 fitted to the 2 nd eccentric body shaft bearing 34 and an outer peripheral surface 133 on which the 1 st eccentric body shaft bearing 33 is provided. The direction in which the eccentric portion 128 of the eccentric body shaft 12 in the radial direction is eccentric to the outermost side is referred to as a maximum eccentric direction, and the direction in which the eccentric portion is eccentric to the opposite side is referred to as a maximum reverse eccentric direction. In fig. 4 and 5, the eccentric portion 128-a of the eccentric body shaft 12 indicates the maximum eccentric direction, and the eccentric portion 128-B indicates the maximum reverse eccentric direction. The symbol 129 represents the outer circumference in the maximum eccentric direction of the eccentric portion 128-A, and the symbol 130 represents the outer circumference in the maximum anti-eccentric direction of the eccentric portion 128-B. The outer peripheral line a is a line extending the outer peripheral position in the maximum eccentricity direction of the eccentric portion 128-a in the axial direction, and the outer peripheral line B is a line extending the outer peripheral position in the maximum anti-eccentricity direction of the eccentric portion 128-B in the axial direction.

In the present embodiment, the axial movement of the eccentric body bearing 30 is restricted by the pressing portion 40, and the pressing portion 40 has a cylindrical portion 402 extending in the axial direction and a flange portion 404 extending in the radial direction of the cylindrical portion 402. At this time, the lubricant G can be stored in the space inside the cylindrical portion 402.

From the viewpoint of ensuring a space for storing lubricant G around rolling elements 302, it is preferable that axial dimension W1 of cylindrical portion 402 is large. Therefore, in the present embodiment, the axial dimension W1 of the cylindrical portion 402 is larger than the axial dimension W2 of the annular portion 306 of the holder 304 of the eccentric body bearing 30. In this case, the storage space for lubricant G can be enlarged with the overall axial dimension fixed.

Similarly, in the present embodiment, from the viewpoint of securing a space for storing the lubricant G, the axial dimension W1 of the cylindrical portion 402 is larger than the axial dimension W3 of the flange portion 404. In this case, the storage space for the lubricant G can be enlarged with the overall axial dimension of the pressing portion 40 fixed.

Similarly, in the present embodiment, the eccentric body shaft 12 has a recess 124 recessed inward in the radial direction at a position overlapping the pressing portion 40 when viewed in the radial direction, from the viewpoint of securing a space for storing the lubricant G. By having the concave portion 124, the holding space of the lubricant G becomes large accordingly. The recess 124 may be opposed to the annular portion 306 of the retainer 304 in the radial direction (overlap when viewed in the radial direction). In this case, the lubricant G in the recess 124 is easily wound around the eccentric body bearing 30, which is advantageous for improving the lubricity.

If the recess 124 is far from the lubricant G storage space, the lubricant G in the recess 124 is less likely to be wound around the eccentric body bearing 30. Therefore, in the present embodiment, the recess 124 overlaps with (faces in the radial direction) the flange 404 when viewed in the radial direction. At this time, the lubricant G in the recess 124 effectively contributes to lubrication of the eccentric body bearing 30.

If the lubricant G in the recess 124 escapes to the opposite input side, lubrication of the eccentric body bearing 30 is not facilitated. Therefore, in the present embodiment, the eccentric body shaft 12 has a convex portion 126 that protrudes outward in the radial direction at a position adjacent to the concave portion 124 on the opposite side from the eccentric body bearing 30. At this time, the lubricant G in the concave portion 124 can be blocked, and the escape toward the opposite input side can be reduced. In the present embodiment, the axial dimensions of the concave portion 124 and the convex portion 126 are substantially the same.

If the positional relationship between the pressing portion 40 and the recess 124 is unstable, the lubricating property improving effect of the eccentric body bearing 30 by the lubricant G in the recess 124 becomes unstable. Therefore, in the present embodiment, the pressing portion 40 has an abutting portion 406 that is provided on the opposite side of the cylindrical portion 402 from the flange portion 404 and abuts against the convex portion 126 to restrict the axial movement of the pressing portion 40. At this time, by making the convex portion 126 axially face the abutting portion 406, the position of the pressing portion 40 with respect to the eccentric body shaft 12 can be stabilized, and the lubricity improving effect by the lubricant G can be stabilized. The abutment portion 406 exists in the axial gap between the inner race 334 of the 1 st eccentric body shaft bearing 33 and the projection 126, and abuts against both in the axial direction.

From the viewpoint of securing the storage space for the lubricant G, in the present embodiment, as shown in fig. 4, the outer periphery 407 of the cylindrical portion 402 is located radially outward of the outer periphery 129 of the eccentric portion 128 of the eccentric body shaft 12 in the maximum eccentric direction of the eccentric body shaft 12. By increasing the outer circumference 407, the storage space for the lubricant G can be increased. In the present embodiment, the entire axial range of the outer periphery 407 of the cylindrical portion 402 is located radially outward of the eccentric portion 128 in the maximum eccentric direction of the eccentric body shaft 12.

In the present embodiment, the outer periphery 407 of the cylindrical portion 402 is located radially inward of the outer periphery 335 of the inner ring 334 of the 1 st eccentric body bearing 33. In other words, the outer diameter of the outer periphery 407 is smaller than the outer diameter of the outer periphery 335. In this case, the pressing portion 40 can reduce the possibility of interference with the holder (not shown) of the 1 st eccentric body bearing 33.

In the present embodiment, as shown in fig. 5, the outer periphery 130 (outer peripheral line B) of the eccentric portion 128 of the eccentric body shaft 12 is located radially inward of the outer periphery 131 of the convex portion 126 in the maximum anti-eccentric direction of the eccentric body shaft 12. In the present embodiment, as shown in fig. 4, the outer periphery 129 (outer peripheral line a) of the eccentric portion 128 of the eccentric body shaft 12 is located radially outward of the outer periphery 131 of the convex portion 126 in the maximum eccentric direction of the eccentric body shaft 12.

In the present embodiment, as shown in fig. 4 and 5, the cylindrical portion 402 has a shape whose diameter increases toward the eccentric body bearing 30 side in the axial direction, and the outline of the outer periphery is inclined with respect to the axial direction. The cylindrical portion 402 may have, for example, a conical shape, and the contour line of the outer periphery may be a straight line or a curved line. At this time, by increasing the diameter of the eccentric body bearing 30 side, the storage space of the lubricant G can be enlarged as compared with the case where the diameter of the eccentric body bearing 30 side is small.

In the present embodiment, as shown in fig. 4, the outer periphery 408 of the flange portion 404 is positioned radially outward of the outer periphery 308 of the holder 304 in the maximum eccentric direction of the eccentric body shaft 12. At this time, the outer periphery 408 of the flange portion 404 blocks the lubricant G near the cage 304, thereby reducing the escape of the lubricant G.

In the present embodiment, as shown in fig. 5, the inner periphery 409 of the flange portion 404 is positioned radially inward of the outer periphery 308 of the retainer 304 in the maximum anti-eccentric direction of the eccentric body shaft 12. In this case, since the contact area between the flange portion 404 and the annular portion 306 of the retainer 304 can be ensured, the possibility of the retainer 304 falling off during the manufacturing process can be reduced.

Next, the operation of the reduction gear transmission 100 configured as above will be described. When the rotation is transmitted from the motor to the eccentric body shaft 12, the eccentric portion 128 of the eccentric body shaft 12 rotates around the rotation center line passing through the eccentric body shaft 12, and the external gear 14 oscillates via the eccentric body bearing 30. When the external gear 14 oscillates, the meshing positions of the external gear 14 and the internal gear 16 are sequentially shifted. As a result, one of the external gear 14 and the internal gear 16 rotates by the number of teeth difference between the external gear 14 and the internal gear 16 for each rotation of the eccentric body shaft 12. In the present embodiment, the external gear 14 rotates and the decelerated rotation is output from the 1 st carrier 18 and the 2 nd carrier 20 via the inner pin 32.

Next, the characteristics of the reduction gear transmission 100 configured as described above will be described. The reduction gear transmission 100 includes: an outer gear 14; an eccentric body shaft 12 that eccentrically swings an external gear 14; and an eccentric body bearing 30 disposed between the external gear 14 and the eccentric body shaft 12, wherein axial movement of the eccentric body bearing 30 is restricted by a pressing portion 40, and the pressing portion 40 has a cylindrical portion 402 extending in the axial direction and a flange portion 404 extending in the radial direction of the cylindrical portion 402.

With this configuration, the pressing portion 40 can secure a space in which the lubricant can be stored in the vicinity of the rolling element 302. In addition, this configuration can reduce the influence of the centrifugal force while suppressing an increase in the stirring resistance of the lubricant G. As a result, the lubricity of the eccentric body bearing 30 can be improved.

The above description explains an example of the embodiment of the present invention in detail. The above embodiments are merely specific examples for carrying out the present invention. The contents of the embodiment are not intended to limit the technical scope of the present invention, and various design changes such as changes, additions, deletions, and the like of the constituent elements can be made without departing from the scope of the invention defined in the claims. In the above-described embodiments, the description has been given by giving the words "in the embodiments" and "in the embodiments" to the contents in which such a design change is possible, but this does not mean that the design change is not permitted without the contents of such words. In the drawings, the hatching marked on the cross section is not used to limit the material of the hatched object.

Hereinafter, a modified example will be described. In the drawings and the description of the modified examples, the same or equivalent constituent elements and components as those of the embodiment are denoted by the same reference numerals. The description overlapping with the embodiment is appropriately omitted, and the description will be given with emphasis on the structure different from the embodiment.

[ modified examples ]

In the description of the embodiment, the example of the eccentric oscillating type reduction gear device in which the reduction gear device 100 is a center crank type is shown, but the present invention is not limited to this. The type of the speed reduction mechanism is not particularly limited as long as the speed reduction device is provided with an eccentric body bearing disposed between the external gear and the eccentric body shaft, and for example, a so-called distributed eccentric oscillating type speed reduction device in which a plurality of crankshafts are disposed at positions offset from the center may be employed.

In the description of the embodiment, the example in which the number of the external gears 14 is two is shown, but the number of the external gears may be one or three or more.

In the description of the embodiment, an example in which the inner pins 32 contributing to transmission of the driving force of the external gear 14 are provided as pin members for connecting the carriers 18, 20 is shown. As the pin member for connecting the carriers 18 and 20, a carrier pin that does not contribute to transmission of the driving force, which is different from the inner pin 32, may be provided.

In the description of the embodiment, the example in which the inner pin 32 is formed integrally with the 1 st carrier 18 is shown, but the inner pin 32 may be formed separately from the 1 st carrier 18 and coupled by a fixing member such as a bolt.

In the description of the embodiment, the eccentric body bearing 30 does not have the inner ring and the outer ring, but the eccentric body bearing 30 may have the inner ring or the outer ring.

In the description of the embodiment, the inner rings of the

main bearings

24 and 26 are integrally formed with the wheel carriers 18 and 20, but the inner rings of the main bearings may be formed separately from the wheel carriers.

In the description of the embodiment, the rolling elements 24e and 26e of the

main bearings

24 and 26 are shown as cylindrical rollers, but the rolling elements of the main bearings may have a shape different from that of the cylindrical rollers, such as tapered rollers and balls. The main bearing is not limited to a main bearing formed by a pair of bearings, and may be, for example, a cross roller bearing. In the description of the embodiment, the example in which the rolling elements 332 of the

eccentric body bearings

33 and 34 are balls is shown, but the rolling elements of the eccentric body bearings may have a shape different from a ball (for example, a cylindrical roller shape). In the description of the embodiment, the example in which the rolling elements 302 of the eccentric body bearing 30 are cylindrical rollers is shown, but the rolling elements of the eccentric body bearing may have a shape different from that of the cylindrical rollers (for example, a spherical body or the like).

In the description of the embodiment, the convex portion 126 of the eccentric body shaft 12 is disposed in close proximity to the concave portion 124 as an adjacent example, but a flat portion or the like may be provided between the convex portion and the concave portion of the eccentric body shaft.

In the description of the embodiment, the example in which the entire axial range of the outer periphery 407 of the cylindrical portion 402 is located radially outward of the eccentric portion 128 in the maximum eccentric direction of the eccentric body shaft 12 is shown as an example in which the outer periphery is located radially outward of the eccentric portion 128 in the maximum eccentric direction of the eccentric body shaft 12, but the outer periphery may be located radially outward of the eccentric portion 128 in which a part of the axial range of the outer periphery of the cylindrical portion is located radially outward of the eccentric portion.

The above modifications also have the same operational effects as the embodiment.

Any combination of the constituent elements and the modified examples of the above embodiments is also effective as an embodiment of the present invention. The new embodiment which is produced by the combination has the effects of both the combined embodiment and the modified example.

Claims

1. An eccentric oscillating type reduction gear device, comprising:

an outer gear;

an eccentric body shaft that eccentrically swings the external gear; and

an eccentric body bearing disposed between the external gear and the eccentric body shaft, the eccentric oscillating type reduction gear being characterized in that,

the axial movement of the eccentric body bearing is limited by the pressing part,

the pressing portion has a cylindrical portion extending in an axial direction and a flange portion extending in a radial direction of the cylindrical portion.

2. The eccentric oscillating type reduction gear according to claim 1,

the cylindrical portion has an axial dimension larger than an axial dimension of an annular portion of a retainer of the eccentric bearing.

3. The eccentric oscillating type reduction gear according to claim 1 or 2,

the cylindrical portion has an axial dimension larger than an axial dimension of the flange portion.

4. The eccentric oscillating type reduction gear according to any one of claims 1 to 3,

the eccentric body shaft has a recess that is recessed inward in the radial direction at a position that overlaps the pressing portion when viewed in the radial direction.

5. The eccentric oscillating type reduction gear according to claim 4,

the recessed portion overlaps with the flange portion when viewed in a radial direction.

6. The eccentric oscillating type reduction gear according to claim 4 or 5,

the eccentric body shaft has a convex portion protruding outward in the radial direction at a position adjacent to a side of the concave portion opposite to the eccentric body bearing.

7. The eccentric oscillating type reduction gear according to claim 6,

the pressing portion has an abutting portion provided on a side of the cylindrical portion opposite to the flange portion, and the abutting portion abuts against the convex portion to restrict the pressing portion from moving in the axial direction.

8. The eccentric oscillating-type reduction gear according to any one of claims 1 to 7,

the outer periphery of the cylindrical portion is located radially outward of the outer periphery of the eccentric portion of the eccentric body shaft in a maximum eccentric direction of the eccentric body shaft.

9. The eccentric oscillating type reduction gear according to claim 6 or 7,

the outer periphery of the eccentric portion of the eccentric body shaft is located radially inward of the outer periphery of the convex portion in a maximum anti-eccentric direction of the eccentric body shaft.

10. The eccentric oscillating-type reduction gear according to any one of claims 1 to 9,

the cylindrical portion has a shape in which the diameter of the eccentric body bearing side in the axial direction becomes larger.

11. The eccentric oscillating-type reduction gear according to any one of claims 1 to 10,

the outer periphery of the flange portion is located radially outward of the outer periphery of the retainer of the eccentric body bearing in a maximum eccentric direction of the eccentric body shaft.

12. The eccentric oscillating-type reduction gear according to any one of claims 1 to 11,

the inner periphery of the flange portion is positioned radially inward of the outer periphery of the retainer of the eccentric body bearing in a maximum anti-eccentric direction of the eccentric body shaft.