Eccentric oscillation type speed reducer

Abstract

To provide an eccentric oscillation type speed reducer in which a carrier is hard to come off from a pin member.SOLUTION: An eccentric oscillation type speed reducer 100 is equipped with a crank shaft 12, external tooth gears 14 and 15 eccentrically oscillating by the crank shaft 12, a first carrier 18 disposed on one side in axial directions of the external tooth gears 14 and 15, a second carrier 20 disposed on the other side in the axial directions of the external tooth gears 14 and 15, and a pin member loosely inserted in the external tooth gears 14 and 15 and coupling the first carrier 18 and the second carrier 20. The second carrier 20 supports an outer peripheral side of a crank shaft bearing 32 externally fitted with the crank shaft 12, and is restricted by the crank shaft bearing 32 in movement in an axial direction opposite to the first carrier 18 side.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an eccentric oscillating type reduction gear device. [Background technology]

[0002] Patent Document 1 describes a differential reduction gear with a carrier connected to an output shaft via a pin member. This reduction gear includes an output shaft supported within a casing, an internal gear, an input shaft that coaxially passes through the output shaft and the internal gear and is supported via a ball bearing, an external gear that inscribes and meshes with the internal gear, and a carrier connected to the output shaft via a pin member into which the external gear is loosely inserted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-155265 A Summary of the Invention [Problem to be solved by the invention]

[0004] The reducer described in Patent Document 1 includes a carrier connected to an output shaft, and the carrier is coupled to a pin member. In this reducer, there is a concern that the carrier may come off the pin member in the axial direction due to the influence of a radial load or the like applied to the pin member.

[0005] In view of the above problems, an object of the present invention is to provide an eccentric oscillating type reduction gear transmission in which the carrier is less likely to come off the pin member. [Means for solving the problem]

[0006] In order to solve the above problems, an eccentric oscillating type reduction gear according to one embodiment of the present invention includes a crankshaft, an external gear that eccentrically oscillates due to the crankshaft, a first carrier arranged on one axial side of the external gear, a second carrier arranged on the other axial side of the external gear, and a pin member that is loosely inserted into the external gear and connects the first carrier and the second carrier. The second carrier supports the outer periphery of a crankshaft bearing that is fitted onto the crankshaft, and its axial movement toward the side opposite the first carrier is restricted by the crankshaft bearing.

[0007] Any combination of the above components, or mutual substitution of the components or expressions of the present invention between methods, systems, etc. are also valid aspects of the present invention. Effect of the Invention

[0008] According to the present invention, it is possible to provide an eccentric oscillating type reduction gear transmission in which the carrier is unlikely to come off the pin member. [Brief description of the drawings]

[0009] [Figure 1] 1 is a side cross-sectional view showing an eccentric oscillating type reduction gear transmission according to a first embodiment. [Diagram 2] FIG. 3 is a side cross-sectional view showing the crankshaft of FIG. 2. [Diagram 3] FIG. 6 is a side cross-sectional view showing an eccentric oscillating type reduction gear transmission according to a second embodiment. [Figure 4] FIG. 4 is a diagram showing the second carrier of FIG. 3; [Diagram 5] FIG. 11 is a side cross-sectional view showing an eccentric oscillating type reduction gear transmission according to a third embodiment. [Figure 6] FIG. 11 is a side cross-sectional view showing an eccentric oscillating type reduction gear transmission according to a fourth embodiment. [Figure 7] FIG. 13 is a side cross-sectional view showing an eccentric oscillating type reduction gear transmission according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described below based on preferred embodiments with reference to the drawings. In the embodiments and modified examples, the same or equivalent components and members are given the same reference numerals, and duplicated descriptions are omitted as appropriate. The dimensions of the members in each drawing are enlarged or reduced as appropriate for ease of understanding. Some of the members that are not important for explaining the embodiments are omitted in each drawing.

[0011] In addition, terms including ordinal numbers such as first, second, etc. are used to describe various components, but these terms are used only for the purpose of distinguishing one component from another component, and the components are not limited by these terms.

[0012] [First embodiment] Hereinafter, the configuration of an eccentric oscillating type reduction gear transmission 100 (hereinafter, sometimes simply referred to as "reduction gear transmission 100") according to a first embodiment of the present disclosure will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a side cross-sectional view that shows a schematic diagram of the reduction gear transmission 100. There is no limitation on the application of the reduction gear transmission 100, and the reduction gear transmission 100 of this example can be used for various applications such as robots.

[0013] The overall configuration of the reduction gear 100 will be described. The reduction gear 100 mainly includes a crankshaft 12, external gears 14, 15, an internal gear 16, carriers 18, 20, a casing 22, a main bearing 24, a movement restricting mechanism 25, retaining portions 26, 27, crankshaft bearings 30, 32, eccentric bearings 34, 36, and an inner pin 38. The reduction gear 100 is a center crank type planetary gear device that oscillates the external gears 14, 15 via the eccentric bearings 34, 36 as the crankshaft 12 rotates, and transmits the rotation of the external gears 14, 15 to the carriers 18, 20 via the inner pin 38.

[0014] Hereinafter, the direction along the central axis La of the internal gear 16 will be referred to as the "axial direction," and the circumferential direction and radial direction of a circle centered on the central axis La will be referred to as the "circumferential direction" and the "radial direction," respectively. Also, hereinafter, for convenience, one side in the axial direction (the right side in the figure) will be referred to as the input side, and the other side (the left side in the figure) will be referred to as the anti-input side. Such designations of directions do not limit the usage orientation of the reduction gear 100, and the reduction gear 100 can be used in any orientation.

[0015] The reduction gear 100 of this embodiment functions as a center crank type eccentric oscillating reducer in which the crankshaft 12 is disposed coaxially with the central axis La of the internal gear 16. The reduction gear 100 has a hollow portion H that penetrates the center in the axial direction.

[0016] The crankshaft 12 has a hollow cylindrical shape with a hollow portion H at the center. For example, a motor shaft is connected to the input end of the crankshaft 12 by a connector such as a bolt. The crankshaft 12 has multiple eccentric portions and functions as an eccentric body that oscillates the external gear. In this embodiment, the crankshaft 12 has two eccentric portions 12a and 12b that are 180° out of phase with each other.

[0017] The eccentric parts 12a and 12b include a first eccentric part 12a and a second eccentric part 12b provided on the input side of the first eccentric part 12a. The direction in which the outer peripheral surfaces of the eccentric parts 12a and 12b are radially farthest from the central axis La is called the eccentric direction, and the direction opposite to the eccentric direction is called the anti-eccentric direction. In other words, the outer peripheral surface in the anti-eccentric direction is the part that is radially closest to the central axis La. In FIG. 1, the eccentric direction of the first eccentric part 12a is the upward direction in the figure, and the eccentric direction of the second eccentric part 12b is the downward direction in the figure. The eccentric parts 12a and 12b protrude in the eccentric direction and are recessed in the anti-eccentric direction. The number of eccentric parts is not limited to two, and may be one or three or more.

[0018] Please also refer to Fig. 2. Fig. 2 is a cross-sectional view showing the crankshaft 12. The crankshaft 12 is supported by the carriers 18, 20 and the casing 22 via crankshaft bearings 30, 32. The crankshaft 12 has journal portions 12c, 12d supported by the crankshaft bearings 30, 32. The journal portions 12c, 12d include a first journal portion 12c provided on the anti-input side of the eccentric portion 12a and a second journal portion 12d provided on the input side of the eccentric portion 12b. A first crankshaft bearing 30 (described later) is fitted onto the first journal portion 12c, and a second crankshaft bearing 32 (described later) is fitted onto the second journal portion 12d.

[0019] The crankshaft bearings 30, 32 support the crankshaft 12. The crankshaft bearings 30, 32 include a first crankshaft bearing 30 arranged on the anti-input side of the external gears 14, 15, and a second crankshaft bearing 32 arranged on the input side of the external gears 14, 15. There are no limitations on the configuration of the crankshaft bearings 30, 32, but the rolling elements of the crankshaft bearings 30, 32 in this example are spherical.

[0020] The first crankshaft bearing 30 is fitted onto the crankshaft 12, and its movement towards the anti-input side is restricted by a washer 41 engaged in an outer circumferential groove of the crankshaft 12. The second crankshaft bearing 32 is fitted onto the crankshaft 12, and its movement towards the input side is restricted by a washer 42 engaged in an outer circumferential groove provided in the crankshaft 12, and a washer 43 engaged in an inner circumferential groove provided in a bearing support hole 22h of a fourth casing 22d described later.

[0021] A first oil seal 45 is provided adjacent to the first crankshaft bearing 30 on the anti-input side thereof with a washer 41 sandwiched therebetween. A second oil seal 46 is provided adjacent to the input side of the second crankshaft bearing 32 with washers 42, 43 sandwiched therebetween. The first oil seal 45 is disposed between a radial center hole 18h of a first carrier 18 (described later) and the crankshaft 12. The second oil seal 46 is disposed between a bearing support hole 22h of the fourth casing 22d and the crankshaft 12.

[0022] The eccentric body bearings 34, 36 are disposed between the eccentric parts 12a, 12b and the external gears 14, 15. The eccentric body bearings 34, 36 include a first eccentric body bearing 34 disposed on the outer periphery of the first eccentric part 12a and a second eccentric body bearing 36 disposed on the outer periphery of the second eccentric part 12b. The eccentric body bearings 34, 36 are full complement bearings having a plurality of rollers 34a, 36a as rolling elements.

[0023] The external gears 14, 15 include a first external gear 14 arranged on the outer periphery of the first eccentric bearing 34, and a second external gear 15 arranged on the outer periphery of the second eccentric bearing 36. The carriers 18, 20 include a first carrier 18 arranged on the anti-input side of the external gears 14, 15, and a second carrier 20 arranged on the input side of the external gears 14, 15.

[0024] The external gears 14, 15 are rotatably supported by the corresponding eccentric parts 12a, 12b via eccentric body bearings 34, 36. The external gears 14, 15 are formed with center holes 14c, 15c and multiple inner pin holes 14h, 15h. The center holes 14c, 15c are through holes provided at the centers of the external gears 14, 15. The multiple inner pin holes 14h, 15h are through holes provided at positions offset from the centers of the external gears 14, 15. In the example of FIG. 1, multiple (e.g., six) inner pin holes 14h, 15h are arranged at predetermined intervals (e.g., 60°) in the circumferential direction. An inner pin 38 is inserted into the inner pin holes 14h, 15h. The teeth formed on the outer periphery of the external gears 14, 15 rotate while meshing with the teeth of the internal gear 16, causing the external gears 14, 15 to oscillate.

[0025] The internal gear 16 meshes with the external gears 14, 15. The internal gear 16 in this embodiment is composed of an internal gear main body 16b integrated with the inner periphery of a casing 22 (a third casing 22c described later) and an outer pin 16a (pin member) rotatably supported by the internal gear main body 16b. The outer pin 16a constitutes the internal teeth of the internal gear 16. The number of internal teeth of the internal gear 16 (the number of outer pins 16a) is slightly more than the number of external teeth of the external gears 14, 15 (by one in this example). The input side end of the outer pin 16a has its axial movement restricted by a side surface of a fourth casing 22d (described later) on the opposite side to the input side.

[0026] The axial movement of the end portion of the outer pin 16a on the non-input side is restricted by the input side surface of the restricting washer 40. The restricting washer 40 is a hollow disk-shaped member whose outer periphery is sandwiched between a second casing 22b and a third casing 22c described below.

[0027] The carriers 18, 20 are annular members. The first carrier 18 supports the end of the crankshaft 12 on the non-input side via a first crankshaft bearing 30. The first carrier 18 has a radial center hole 18h and a plurality of through holes 18p. The radial center hole 18h supports the first crankshaft bearing 30. The plurality of (e.g., six) through holes 18p are provided at positions radially offset from the central axis La at predetermined intervals (e.g., 60°) in the circumferential direction.

[0028] The second carrier 20 supports the input side end of the crankshaft 12 via a second crankshaft bearing 32. The second carrier 20 has a radial center hole 20h and a plurality of through holes 20p. The radial center hole 20h supports the second crankshaft bearing 32. The plurality of (e.g., six) through holes 20p are provided at positions radially offset from the central axis La at predetermined intervals (e.g., 60°) in the circumferential direction.

[0029] The first carrier 18 and the second carrier 20 are connected by an inner pin 38 that is inserted into the through holes 18p, 20p. The second carrier 20 in this example functions as an inner pin support member that supports the input side of the inner pin 38.

[0030] One of the first carrier 18 and the casing 22 functions as an output member that outputs rotational power to a driven device (not shown), and the other functions as a fixed member that is fixed to an external member for supporting the reduction gear transmission 100. In this embodiment, the output member is the first carrier 18, and the fixed member is the casing 22. A bolt hole 18c for connecting a driven device is provided in an end face of the first carrier 18 on the opposite input side.

[0031] The inner pin 38 axially passes through the inner pin holes 14h, 15h of the external gears 14, 15 at a position radially offset from the axis of the external gears 14, 15. In this example, a plurality of (e.g., six) inner pins 38 are arranged at predetermined intervals in the circumferential direction. FIG. 1 shows one inner pin 38. The inner pin 38 is a connecting pin that is inserted into the through hole 18p of the first carrier 18 from the anti-input side, passes through the inner pin holes 14h, 15h, and fits into the through hole 20p of the second carrier 20, thereby connecting the first carrier 18 and the second carrier 20.

[0032] A sleeve 38s is rotatably fitted onto the outer periphery of the inner pin 38. The sleeve 38s is inserted into the inner pin holes 14h, 15h with a gap therebetween. The inner pin 38 abuts against a portion of the inner pin holes 14h, 15h via the sleeve 38s. The inner pin 38 restrains the rotation of the external gears 14, 15 and allows only their oscillation. With this configuration, the carriers 18, 20 move in synchronization with the rotation of the external gears 14, 15 via the inner pin 38.

[0033] The casing 22 constitutes the outer shell of the reduction gear 100. In particular, the casing 22 covers the radial outside of the first carrier 18 and the second carrier 20. The casing 22 includes a first casing 22a, a second casing 22b, a third casing 22c, and a fourth casing 22d that are stacked in this order from the anti-input side toward the input side. The first casing 22a, the second casing 22b, and the third casing 22c are hollow cylindrical members. The fourth casing 22d is a substantially disk-shaped member having a bearing support hole 22h in the radial center.

[0034] The first casing 22a and the second casing 22b mainly surround the first carrier 18. The third casing 22c mainly surrounds the external gears 14, 15. The internal gear 16 is provided on the inner circumferential surface of the third casing 22c. The fourth casing 22d mainly covers the outer circumferential surface and input side surface of the second carrier 20. The bearing support hole 22h of the fourth casing 22d is an axial through hole that supports the outer circumferential side of the second crankshaft bearing 32.

[0035] The first casing 22a, the second casing 22b, and the third casing 22c are fixed by a bolt B1. The bolt B1 passes through the first casing 22a and the second casing 22b from the non-input side and is screwed into a screw hole 22m of the third casing 22c. The fourth casing 22d is fixed to the third casing 22c by a bolt B2. The bolt B2 passes through the fourth casing 22d from the input side and is screwed into a screw hole 22n of the third casing 22c. With this configuration, the casing 22 is integrated.

[0036] The main bearing 24 is disposed on the non-input side of the external gears 14, 15. The main bearing 24 is disposed between the first carrier 18 and the casing 22. There are no limitations on the configuration of the main bearing 24, but the main bearing 24 in this example is a cross roller bearing. An outer ring of the main bearing 24 is formed integrally with the first casing 22a and the second casing 22b. An inner ring of the main bearing 24 is formed integrally with the carrier 18. The main bearing 24 supports the first carrier 18 rotatably relative to the casing 22.

[0037] The configuration around the rollers 34a, 36a will be described with reference to Figs. 1 and 2. Fig. 2 is a cross-sectional view showing the crankshaft 12. In order to increase the strength of the eccentric body bearings 34, 36, it is possible to increase the diameter of the rollers 34a, 36a of the eccentric body bearings 34, 36. However, simply increasing the diameter of the rollers will increase the size of the reduction gear 100 accordingly. Therefore, in this embodiment, the first outer diameter D1 of the eccentric parts 12a, 12b of the crankshaft 12 is smaller than the second outer diameter D2 of the bearing parts 12c, 12d supported by the crankshaft bearings 30, 32 of the crankshaft 12. Since the first outer diameter D1 is small, the size of the device can be suppressed even if the diameter of the rollers 34a, 36a is increased.

[0038] When the diameter of the eccentric portions 12a, 12b is reduced, the strength of the crankshaft 12 may decrease. In particular, stress may be concentrated at the corners of the regions of the eccentric portions 12a, 12b recessed in the anti-eccentric direction (hereinafter referred to as "recessed corners"). In the example of FIG. 2, in order to disperse the stress at the recessed corners, the regions of the eccentric portions 12a, 12b recessed in the anti-eccentric direction have curved portions 12k. The curved portions 12k are portions that connect the first opposing surfaces 12u axially opposing the rollers 34a, 36a to the second opposing surfaces 12v radially opposing the rollers 34a, 36a in the anti-eccentric direction region of the eccentric portions 12a, 12b by a curved line.

[0039] Furthermore, the axial ends of the rollers 34a, 36a are provided with curved surface portions 34k, 36k that avoid interference with the curved portion 12k. The curved portion 12k and the curved surface portions 34k, 36k may have various shapes, such as a curved surface, a flat surface, or a composite surface of a curved surface and a flat surface, in addition to an R shape. The shapes of the curved portion 12k and the curved surface portions 34k, 36k can be set by simulation according to the desired strength.

[0040] Providing curved surface portions 34k, 36k on the rollers 34a, 36a increases the possibility that the rollers 34a, 36a will come off toward the crankshaft bearings 30, 32. In addition, the roller end faces will slide against different rollers, such as the external gear, the eccentric portion, and the adjacent roller, which is detrimental to the roller's lifespan. To prevent the rollers from coming off, it is possible to provide a flange portion that is integral with the crankshaft and has a larger diameter than the eccentric portion, all around the outer periphery. However, in this case, since the flange portion is integral with the crankshaft, if the outer diameter of the flange portion is made larger, it will interfere with the center hole of the external gear, making assembly difficult.

[0041] Therefore, in this embodiment, in order to restrict axial movement of the rollers 34a, 36a, hollow disk-shaped retaining portions 26, 27 are disposed separately from the crankshaft 12 on the outer periphery of the crankshaft 12. This configuration makes it possible to increase the diameter of the retaining portions 26, 27 while maintaining ease of assembly, and effectively prevents the rollers 34a, 36a from coming off.

[0042] In this embodiment, the anti-slip portions 26, 27 include a first anti-slip portion 26 arranged between the first crankshaft bearing 30 and the first roller 34a, and an intermediate anti-slip portion 27 arranged between the first eccentric bearing 34 and the second eccentric bearing 36.

[0043] The presence of the first retaining portion 26 makes it possible to restrict movement of the first roller 34a towards the first crankshaft bearing 30. The presence of the intermediate retaining portion 27 makes it possible to prevent mutual interference between the first roller 34a and the second roller 36a. As shown in Fig. 1, the intermediate retaining portion 27 abuts against the external gears 14, 15 when it is positioned in the anti-eccentric direction and when it is positioned in the eccentric direction. In this case, the intermediate retaining portion 27 comes into contact with the external gears 14, 15 regardless of the pivot position of the external gears 14, 15, and can also restrict axial movement of the external gears 14, 15.

[0044] 1, in this embodiment, the outer shape of the retaining portions 26, 27 extends radially outward from the center lines L34, L36 of the rollers 34a, 36a located in the eccentric direction. In this case, the rollers 34a, 36a can be more effectively prevented from coming off.

[0045] 2, in this embodiment, the first retaining portion 26 is adjacent to the anti-input side of the first eccentric portion 12a and fits into an extension of the first journal portion 12c toward the input side. The intermediate retaining portion 27 fits into an area in the eccentric direction of the first eccentric portion 12a and an area in the eccentric direction of the second eccentric portion 12b.

[0046] A characteristic configuration of the reduction gear 100 of this embodiment will be described with reference to Figs. 1 and 2. As described above, in the reduction gear 100, the second carrier 20 is coupled to the inner pin 38. In the reduction gear 100, when a radial load is applied to the inner pin 38 from the driven device via the first carrier 18, the inner pin 38 may bend due to the load. When the inner pin 38 is bent, there is a concern that the second carrier 20 may come off the inner pin 38 in the axial direction. Therefore, this embodiment has a movement restriction mechanism 25 for restricting the axial movement of the second carrier 20 to the side opposite the first carrier 18 by the second crankshaft bearing 32.

[0047] As the movement restriction mechanism 25, various configurations are applicable, but in the example of FIG. 1, an extension portion 20c provided on the second carrier 20 is adopted. Specifically, the second carrier 20 has a carrier body portion 20b and an extension portion 20c extending radially from the carrier body portion 20b. The carrier body portion 20b is a hollow disk-shaped portion having a radial center hole 20h and a plurality of through holes 20p into which the inner pin 38 is fitted and fixed. The extension portion 20c is a hollow disk-shaped portion extending radially inward from the inner peripheral surface of the carrier body portion 20b. The axial thickness of the extension portion 20c is thinner than the axial thickness of the carrier body portion 20b. The extension portion 20c blocks a part of the radial center hole 20h.

[0048] The extending portion 20c has a shape that overlaps with the second crankshaft bearing 32 when viewed in the axial direction. That is, the inner peripheral shape of the extending portion 20c is smaller than the outer peripheral shape of the second crankshaft bearing 32. More specifically, the extending portion 20c directly or indirectly abuts against the outer ring 32e of the second crankshaft bearing 32 in the axial direction, but does not abut against the inner ring 32j. With this configuration, the extending portion 20c restricts axial movement of the second carrier 20 to the side opposite the first carrier 18 (the input side).

[0049] It is desirable to be able to adjust the axial position of the second carrier 20. For this reason, in the example of FIG. 1, a shim 44 for adjusting the axial position of the second carrier 20 is disposed between the extension portion 20c and the second crankshaft bearing 32. The shim 44 is a washer for adjusting a gap. A plurality of types of shims 44 with different thicknesses are prepared, and the shim 44 with a thickness corresponding to a desired position of the second carrier 20 is selected and incorporated, thereby making it possible to adjust the axial position of the second carrier 20. The shim 44 can be similarly applied to other embodiments of this specification.

[0050] The operation of the reduction gear 100 will be described. When rotation is transmitted from the motor to the crankshaft 12, the eccentric parts 12a and 12b of the crankshaft 12 rotate around a rotation center line passing through the crankshaft 12, and the external gears 14 and 15 oscillate via the eccentric bearings 34 and 36. When the external gears 14 and 15 oscillate, the meshing positions of the external gears 14 and 15 and the internal gear 16 are shifted sequentially. As a result, each time the crankshaft 12 rotates once, one of the external gears 14 and 15 and the internal gear 16 rotates by an amount corresponding to the difference in the number of teeth between the external gears 14 and 15 and the internal gear 16. In this embodiment, reduced rotation is output from the first carrier 18, which is synchronized with the rotation of the external gears 14 and 15, via the inner pin 38.

[0051] The characteristics of the reduction gear 100 configured as described above will be described below. In the reduction gear 100, the second carrier 20 is restricted from axial movement toward the side opposite the first carrier 18 by the second crankshaft bearing 32, so that the possibility of the second carrier 20 coming out of the inner pin 38 in the axial direction can be reduced.

[0052] Second to fifth embodiments of the present disclosure will be described below. In the drawings and description of the second to fifth embodiments, the same reference numerals are used for components and members that are the same as or equivalent to those of the first embodiment. Descriptions that overlap with the first embodiment will be omitted as appropriate, and the description will focus on configurations that differ from the first embodiment. Therefore, the description of the first embodiment applies to components and members in the second to fifth embodiments that are the same as or equivalent to those of the first embodiment.

[0053] [Second embodiment] The configuration of an eccentric oscillating type reduction gear transmission 100 according to a second embodiment of the present disclosure will be described with reference to Figs. 3 and 4. Fig. 3 is a cross-sectional view showing the overall configuration of the reduction gear transmission 100 according to this embodiment. Fig. 4 is a diagram showing the second carrier 20 as viewed from the input direction. As shown in these figures, this embodiment differs from the first embodiment in that the shape of the second carrier 20 is different, and other configurations are the same as those of the first embodiment. Therefore, the shape of the second carrier 20 will be mainly described.

[0054] When the outer peripheral edge 20q of the carrier body 20b of the second carrier 20 is an acute angle, the end face of the carrier body 20b on the non-input side and the end face of the second external gear 15 on the input side may wear. Therefore, in this embodiment, a chamfered portion is provided on the outer peripheral edge 20q of the end face on the non-input side of the carrier body 20b of the second carrier 20, which is chamfered with a C surface, an R surface, or the like. The size of the chamfered portion can be set by experiment or simulation based on the desired wear level. In the example of FIG. 3, the chamfered portion is set to approximately 40% of the thickness dimension of the carrier body 20b.

[0055] When the volume of the second carrier 20 including the extension portion 20c becomes large and the internal space becomes narrow, the circulation of the lubricant such as grease may be hindered, and the lubrication performance between the inner pin 38 and the rollers 34a, 36a may be reduced. Therefore, in this embodiment, the carrier body portion 20b and the extension portion 20c are provided with a notch 20g recessed radially outward. The notch 20g may include a bottomed groove 20v and a bottomless groove 20w. In the example of FIG. 4, the notch 20g has a groove shape extending in the radial direction, but is not limited to a shape extending in the radial direction. In the example of FIG. 4, the longitudinal direction of the notch 20g is along the radial direction, but the longitudinal direction of the notch 20g is not limited to the radial direction.

[0056] In the example of FIG. 4, the notches 20g are six grooves extending axially inward from the six through holes 20p. The notches 20g form a circulation path for the lubricant, smoothing the circulation of the lubricant and improving the lubrication performance between the inner pin 38 and the rollers 34a, 36a. The groove width of the notches 20g can be set by experiment or simulation based on the desired lubrication performance. In the example of FIG. 4, the groove width of the notches 20g is set to approximately 40% of the diameter of the through hole 20p.

[0057] If the inner peripheral edge 20k or the edge 20r of the notch 20g has an acute angle, this can cause wear of the second external gear 15. Therefore, in this embodiment, chamfers are provided also on the inner peripheral edge 20k and the edge 20r of the notch 20g.

[0058] This embodiment provides the same functions and effects as those of the first embodiment. In addition, this embodiment can suppress wear between the carrier body 20b and the second external gear 15, and can improve the lubrication performance between the inner pin 38 and the rollers 34a, 36a.

[0059] [Third embodiment] The configuration of an eccentric oscillating type reduction gear transmission 100 according to a third embodiment of the present disclosure will be described with reference to Fig. 5. Fig. 5 is a cross-sectional view showing the overall configuration of the reduction gear transmission 100 according to this embodiment. As shown in Fig. 5, this embodiment differs from the first embodiment in that the second carrier 20 does not have an extension portion and includes an annular member 29 formed separately from the second carrier 20 as a movement restricting mechanism 25, but the other configurations are the same as those of the first embodiment. Therefore, the annular member 29 will be mainly described.

[0060] In this embodiment, an inner circumferential groove 20s is provided in a radial central hole 20h of the second carrier 20, and an annular member 29, which is a hollow disk-shaped washer, is fitted in this inner circumferential groove 20s. The annular member 29 extends radially inward from the second carrier 20 and has a shape that overlaps with the second crankshaft bearing 32 when viewed in the axial direction. In other words, the inner diameter of the annular member 29 is smaller than the outer diameter of the second crankshaft bearing 32.

[0061] Specifically, the annular member 29 directly or indirectly contacts the outer ring 32e of the second crankshaft bearing 32 in the axial direction, but does not contact the inner ring 32j. With this configuration, the annular member 29 restricts the axial movement of the second carrier 20.

[0062] This embodiment has the same functions and effects as those of the first embodiment. In addition, in this embodiment, the movement restriction mechanism 25 (annular member 29) is formed separately from the carrier body 20b, so that the shapes of the respective members are simplified and processing is easy.

[0063] [Fourth embodiment] The configuration of an eccentric oscillating type reduction gear transmission 100 according to a fourth embodiment of the present disclosure will be described with reference to Fig. 6. Fig. 6 is a cross-sectional view showing the overall configuration of the reduction gear transmission 100 according to this embodiment. As shown in Fig. 6, this embodiment differs from the first embodiment in that the second carrier 20 does not have an extension portion, but has a protruding portion 47 that protrudes radially outward from the second crankshaft bearing 32 as a movement restricting mechanism 25, but the other configurations are the same as those of the first embodiment. Therefore, the protruding portion 47 will be mainly described.

[0064] In this embodiment, the second crankshaft bearing 32 has a protruding portion 47 that protrudes radially outward from the outer ring 32e, and the protruding portion 47 overlaps with the second carrier 20 when viewed in the axial direction, thereby restricting the axial movement of the second carrier 20. The protruding portion 47 may be formed integrally with the outer ring 32e or may be formed separately. In the example of Fig. 6, an outer peripheral groove 32s is provided in the outer ring 32e of the second crankshaft bearing 32, and the protruding portion 47, which is a hollow disk-shaped washer, is attached to this outer peripheral groove 32s.

[0065] The overhanging portion 47 has a shape that overlaps with the second carrier 20 when viewed in the axial direction. In other words, the outer diameter of the overhanging portion 47 is larger than the inner diameter of the second carrier 20 and does not reach the through hole 20p. Specifically, the overhanging portion 47 abuts directly or indirectly on the input side end face of the second carrier 20 in the axial direction. With this configuration, the overhanging portion 47 restricts the axial movement of the second carrier 20.

[0066] In this embodiment, a hollow disk-shaped second retaining portion 28 is disposed between the second crankshaft bearing 32 and the second roller 36a. The presence of the second retaining portion 28 makes it possible to restrict movement of the second roller 36a toward the second crankshaft bearing 32.

[0067] This embodiment provides the same functions and effects as those of the first embodiment. In addition, in this embodiment, the movement restriction mechanism 25 (the protruding portion 47) is formed separately from the outer ring 32e, so that the shapes of the respective members are simplified and processing is easy.

[0068] [Fifth embodiment] The configuration of an eccentric oscillating type reduction gear 100 according to a fifth embodiment of the present disclosure will be described with reference to Fig. 7. Fig. 7 is a cross-sectional view showing the overall configuration of the reduction gear 100 according to this embodiment. As shown in Fig. 7, this embodiment differs from the first embodiment in that it does not have oil seals 44, 45, and instead uses sealed ball bearings for the crankshaft bearings 30, 32. The other configurations are the same as those of the first embodiment.

[0069] In this embodiment, the first crankshaft bearing 30 is provided with a shield plate 30p at its end on the non-input side, and the second crankshaft bearing 32 is provided with a shield plate 32p at its end on the input side.

[0070] This embodiment provides the same functions and effects as those of the first embodiment. In addition, since this embodiment does not have the oil seals 44, 45, it is possible to shorten the axial length of the crankshaft 12 and reduce the thickness of the fourth casing 22d, which is advantageous for reducing the thickness of the reduction gear transmission 100.

[0071] The above describes in detail the examples of the embodiments of the present invention. The above-mentioned embodiments are merely examples of the implementation of the present invention. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes such as changes, additions, and deletions of components are possible within the scope of the invention as defined in the claims. In the above-mentioned embodiments, the contents for which such design changes are possible are described with notations such as "of the embodiment" and "in the embodiment", but this does not mean that design changes are not allowed for contents without such notations. In addition, hatching on the cross sections of the drawings does not limit the material of the objects to which the hatching is applied.

[0072] The following describes the modified examples. In the drawings and description of the modified examples, the same or equivalent components and members as those in the embodiment are denoted by the same reference numerals. Descriptions that overlap with the embodiment will be omitted as appropriate, and the description will focus on configurations that differ from the embodiment.

[0073] [Variations] In the description of the embodiment, an example in which the casing 22 is made up of four members has been shown, but the casing may be made up of three or less or five or more members.

[0074] In the description of the embodiment, an example in which the number of external gears is two has been shown, but the number of external gears may be one or three or more.

[0075] As a pin member for connecting the carriers 18, 20, a carrier pin that does not contribute to the transmission of driving force may be provided in addition to the inner pin 38.

[0076] In the description of the embodiment, an example has been shown in which the inner pin 38 is separate from the first carrier 18, but the inner pin 38 may be formed integrally with the first carrier 18.

[0077] In the description of the embodiment, an example has been shown in which the inner ring of the main bearing 24 is formed integrally with the carrier 18, and the outer ring of the main bearing 24 is formed integrally with the casing 22, but the inner ring or the outer ring of the main bearing may be separate from the carrier or the casing.

[0078] Each of the above-described modified examples provides the same functions and effects as the embodiment.

[0079] Any combination of the components and modifications of the above-described embodiments is also useful as an embodiment of the present invention. A new embodiment resulting from the combination has the combined effects of the respective embodiments and modifications. [Explanation of symbols]

[0080] DESCRIPTION OF SYMBOLS 12 crankshaft, 12a first eccentric portion, 12b second eccentric portion, 12c first journal portion, 12d second journal portion, 14 first external gear, 15 second external gear, 18 first carrier, 20 second carrier, 20b carrier main body portion, 20c extension portion, 22 casing, 25 movement restricting mechanism, 29 annular member, 30 first crankshaft bearing, 32 second crankshaft bearing, 34 first eccentric body bearing, 36 second eccentric body bearing, 47 extension portion, 100 eccentric oscillating type reduction gear device.

Claims

1. A crankshaft, an external gear that eccentrically oscillates due to the crankshaft; A first carrier disposed on one axial side of the external gear; A second carrier disposed on the other axial side of the external gear; a pin member that is loosely inserted into the external gear and connects the first carrier and the second carrier; Equipped with the second carrier supports an outer circumferential side of a crankshaft bearing fitted onto the crankshaft, and axial movement of the second carrier toward the opposite side to the first carrier is restricted by the crankshaft bearing.

2. The second carrier has a carrier body portion and an extension portion extending radially inward from the carrier body portion, 2. The eccentric oscillating reduction gear device according to claim 1, wherein the extension portion overlaps with the crankshaft bearing when viewed in the axial direction, thereby restricting axial movement of the second carrier toward the side opposite to the first carrier.

3. 3. The eccentric oscillating type reduction gear device according to claim 2, wherein the extension portion has a notch recessed radially outward.

4. 4. The eccentric oscillating type reduction gear device according to claim 3, wherein the notch forms a circulation path for a lubricant.

5. 5. The eccentric oscillating type reduction gear transmission according to claim 2, further comprising a shim for adjusting an axial position of the second carrier disposed between the extension and the crankshaft bearing.

6. a ring-shaped member formed separately from the second carrier and extending radially inward from the second carrier; 2. The eccentric oscillating type reduction gear device according to claim 1, wherein the annular member overlaps with the crankshaft bearing when viewed in the axial direction, thereby restricting axial movement of the second carrier.

7. A protrusion extending radially outward from the crankshaft bearing, 2. The eccentric oscillating reduction gear device according to claim 1, wherein the protruding portion overlaps with the second carrier when viewed in the axial direction, thereby restricting axial movement of the second carrier.

8. a casing that covers the radial outside of the first carrier and the second carrier; 8. The eccentric oscillating type reduction gear transmission according to claim 1, wherein an outer periphery of the crankshaft bearing is supported by the casing.

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