JP2022083709A - Eccentric oscillation type speed reducer - Google Patents

Abstract

To provide an eccentric oscillation type speed reducer in which a roller of an eccentric body bearing is hard to come off.SOLUTION: An eccentric oscillation type speed reducer 100 is equipped with a crank shaft 12 having eccentric portions 12a and 12b, crank shaft bearings 30 and 32 supporting the crank shaft 12, and eccentric body bearings 34 and 36 disposed on the outer side in diametrical directions of the eccentric portions 12a and 12b. The eccentric body bearings 34 and 36 are full type roller bearings, and the eccentric portions 12a and 12b are depressed on a counter eccentric direction side. Rollers 34a and 36a of the eccentric bearings 34 and 36 have outer diameters of axial outer end portions that are smaller than outer diameters of axial center portion, and have coming-off preventive portions 26, 27, and 28 disposed on an outer periphery of the crank shaft 12 to restrict the movement in the axial direction of the rollers 34a and 36a. The coming-off preventive portions 26, 27, and 28 are provided separately from the crank shaft 12.SELECTED DRAWING: Figure 1

Description

The present invention relates to an eccentric swing type speed reducer.

Patent Document 1 describes a differential speed reducer that employs a needle bearing of a full roller as a bearing for an eccentric portion. This speed reducer has an output shaft supported in the casing, an internal gear, an input shaft coaxially penetrating the output shaft and the internal gear and supported via a ball bearing, and an eccentric bearing. It includes an external gear that meshes inscribed with the internal gear and a carrier that is connected to the output shaft via a pin member that loosely inserts the external gear.

Japanese Unexamined Patent Publication No. 2018-155264

In the speed reducer described in Patent Document 1, the external gear is mounted on the eccentric portion of the input shaft via the eccentric portion bearing which is the needle bearing of the full roller. Further, the outer diameter of the eccentric portion of the input shaft is smaller than the outer diameter of the shaft support portion provided with the ball bearing. In this way, when the outer diameter of the eccentric portion of the input shaft is smaller than the outer diameter of the shaft support portion, it is necessary to prevent the inner diameter of the external gear from interfering with the crank shaft when incorporating the external gear. The axial regulation part of the roller of the eccentric bearing cannot be made too large in the radial direction. Therefore, the rollers of the eccentric bearing tend to come off toward the shaft support.

In view of such a problem, an object of the present invention is to provide an eccentric swing type speed reducer in which the rollers of an eccentric body bearing are hard to come off.

In order to solve the above problems, the eccentric swing type speed reducer according to an aspect of the present invention is arranged on a crank shaft having an eccentric portion, a crank shaft bearing supporting the crank shaft, and radially outside the eccentric portion. Eccentric bearings and. The eccentric body bearing is a full roller bearing, and the eccentric part is recessed on the anti-eccentric direction side. , It is arranged on the outer periphery of the crank shaft and has a retaining portion that regulates the axial movement of the roller. The retaining portion is provided separately from the crank shaft.

It should be noted that any combination of the above components and those in which the components and expressions of the present invention are mutually replaced between methods, systems and the like are also effective as aspects of the present invention.

According to the present invention, it is possible to provide an eccentric swing type speed reducer in which the rollers of the eccentric body bearing are hard to come off.

It is a side sectional view which shows the eccentric rocking type speed reduction apparatus which concerns on 1st Embodiment. It is a side sectional view which shows the crank shaft of FIG. It is a side sectional view which shows the eccentric rocking type speed reduction apparatus which concerns on 2nd Embodiment. It is a side sectional view which shows the eccentric rocking type speed reduction apparatus which concerns on 3rd Embodiment. It is a side sectional view which shows the eccentric rocking type speed reduction apparatus which concerns on 4th Embodiment.

Hereinafter, the present invention will be described with reference to each drawing based on a preferred embodiment. In the embodiments and modifications, the same or equivalent components and members are designated by the same reference numerals, and duplicate description thereof will be omitted as appropriate. Further, the dimensions of the members in each drawing are shown in an appropriately enlarged or reduced size for easy understanding. In addition, some of the members that are not important for explaining the embodiment in each drawing are omitted and displayed.

Also, terms including ordinal numbers such as 1st and 2nd are used to describe various components, but this term is used only for the purpose of distinguishing one component from other components, and this term is used. The components are not limited by.

[First Embodiment]
Hereinafter, the configuration of the eccentric swing type speed reducer 100 (hereinafter, may be simply referred to as “speed reduction device 100”) according to the first embodiment of the present disclosure will be described with reference to FIGS. 1 and 2. FIG. 1 is a side sectional view schematically showing the speed reducing device 100. The use of the speed reducer 100 is not limited, and the speed reducer 100 of this example can be used for various purposes such as a robot.

The overall configuration of the speed reducer 100 will be described. The reduction gear 100 includes a crank shaft 12, external gears 14, 15, internal gears 16, carriers 18, 20, a casing 22, a main bearing 24, a retaining portion 26, 27, 28, and a crank shaft. The bearings 30 and 32, the eccentric body bearings 34 and 36, and the inner pin 38 are mainly provided. The speed reducing device 100 swings the external gears 14 and 15 via the eccentric bearings 34 and 36 by the rotation of the crank shaft 12, and rotates the external gears 14 and 15 via the inner pin 38. It is a center crank type planetary gear device that transmits to 20.

Hereinafter, the direction along the central axis La of the internal gear 16 is referred to as "axial direction", and the circumferential direction and the radial direction of the circle centered on the central axis La are referred to as "circumferential direction" and "diameter direction", respectively. do. Hereinafter, for convenience, one side in the axial direction (right side in the figure) is referred to as an input side, and the other side (left side in the figure) is referred to as a non-input side. The notation in such a direction does not limit the posture in which the speed reducer 100 is used, and the speed reducer 100 can be used in any posture.

The speed reducer 100 of the present embodiment functions as a center crank type eccentric swing type speed reducer in which the crank shaft 12 is provided on the coaxial line with the central axis La of the internal gear 16. The speed reducing device 100 has a hollow portion H penetrating in the axial direction in the central portion.

The crank shaft 12 has a hollow cylindrical shape having a hollow portion H in the center. For example, the motor shaft is connected to the end of the crank shaft 12 on the input side by a connecting tool such as a bolt. The crank shaft 12 has a plurality of eccentric portions and functions as an eccentric body that swings the external gear. In this embodiment, the crank shaft 12 has two eccentric portions 12a and 12b that are 180 ° out of phase.

The eccentric portions 12a and 12b include a first eccentric portion 12a and a second eccentric portion 12b provided on the input side of the first eccentric portion 12a. The direction in which the outer peripheral surfaces of the eccentric portions 12a and 12b are most distant from the central axis La in the radial direction is called the eccentric direction, and the direction opposite to the eccentric direction is called the anti-eccentric direction. That is, the outer peripheral surfaces of the eccentric portions 12a and 12b in the anti-eccentric direction are the portions closest to the central axis La in the radial direction. In FIG. 1, the eccentric direction of the first eccentric portion 12a is the upward direction in the figure, and the eccentric direction of the second eccentric portion 12b is the downward direction in the figure. The eccentric portions 12a and 12b protrude in the eccentric direction side and are recessed in the anti-eccentric direction side. The number of eccentric portions is not limited to 2, and may be 1 or 3 or more. Here, "recessed on the anti-eccentric direction side" means that a predetermined range including the anti-eccentric direction position (position 180 degrees from the maximum eccentric direction position) is recessed (distance from the adjacent shaft branch to the central axis La). However, the recessed range is not particularly limited, but in the present embodiment, for example, the recessed range is ± 45 degrees from the anti-eccentric direction.

See also FIG. FIG. 2 is a cross-sectional view showing the crank shaft 12. The crank shaft 12 is supported by the carriers 18 and 20 and the casing 22 via the crank shaft bearings 30 and 32. The crank shaft 12 has shaft support portions 12c and 12d supported by the crank shaft bearings 30 and 32. The shaft support portions 12c and 12d include a first shaft support portion 12c provided on the opposite side of the eccentric portion 12a and a second shaft support portion 12d provided on the input side of the eccentric portion 12b. A first crank shaft bearing 30, which will be described later, is externally fitted to the first shaft support portion 12c, and a second crank shaft bearing 32, which will be described later, is externally fitted to the second shaft support portion 12d.

The crank shaft bearings 30 and 32 support the crank shaft 12. The crank shaft bearings 30 and 32 include a first crank shaft bearing 30 arranged on the opposite side of the external gears 14 and 15 and a second crank shaft bearing 32 arranged on the input side of the external gears 14 and 15. including. The configuration of the crank shaft bearings 30 and 32 is not limited, but the rolling element of the crank shaft bearings 30 and 32 in this example is a sphere.

The first crank shaft bearing 30 is fitted onto the crank shaft 12 and is restricted from moving to the counter-input side by a washer 41 locked in the outer peripheral groove of the crank shaft 12. The second crank shaft bearing 32 is fitted in the crank shaft 12 and is locked in the outer peripheral groove provided in the crank shaft 12, and is provided in the bearing support hole 22h of the fourth casing 22d, which will be described later. The washer 43 locked in the peripheral groove restricts the movement to the input side.

A first oil seal 45 adjacent to the washer 41 is provided on the opposite side of the first crank shaft bearing 30. A second oil seal 46 adjacent to the washer 42, 43 is provided on the input side of the second crank shaft bearing 32. The first oil seal 45 is arranged between the radial center hole 18h of the first carrier 18, which will be described later, and the crank shaft 12. The second oil seal 46 is arranged between the bearing support hole 22h of the fourth casing 22d and the crank shaft 12.

The eccentric body bearings 34 and 36 are arranged between the eccentric portions 12a and 12b and the external gears 14 and 15. The eccentric body bearings 34 and 36 include a first eccentric body bearing 34 arranged on the outer circumference of the first eccentric body portion 12a and a second eccentric body bearing 36 arranged on the outer periphery of the second eccentric body portion 12b. The eccentric body bearings 34 and 36 are full roller bearings having a plurality of rollers 34a and 36a as rolling elements. Here, the total roller bearing refers to a bearing that does not have a cage (retainer) that regulates the contact in the circumferential direction of the rollers adjacent to the circumferential direction (regulates the position in the circumferential direction of each roller).

The external gears 14 and 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 and 20 include a first carrier 18 arranged on the opposite side of the external gears 14 and 15 and a second carrier 20 arranged on the input side of the external gears 14 and 15.

The external gears 14 and 15 are rotatably supported by the corresponding eccentric portions 12a and 12b via the eccentric body bearings 34 and 36. The external gears 14 and 15 are formed with central holes 14c and 15c and a plurality of internal pin holes 14h and 15h. The central holes 14c and 15c are through holes provided at the centers of the external gears 14 and 15. The plurality of inner pin holes 14h and 15h are through holes provided at positions offset from the centers of the external gears 14 and 15. In the example of FIG. 1, a plurality of (for example, six) inner pin holes 14h and 15h are arranged at predetermined intervals (for example, 60 °) in the circumferential direction. The inner pin 38 is inserted through the inner pin holes 14h and 15h. The teeth formed on the outer periphery of the external gears 14 and 15 rotate while meshing with the teeth of the internal gears 16, so that the external gears 14 and 15 swing.

The internal gear 16 meshes with the external gears 14 and 15. The internal gear 16 of the present embodiment has an internal gear body 16b integrated on the inner peripheral side of the casing 22 (a third casing 22c described later) and an external pin rotatably supported by the internal gear body 16b. It is composed of 16a (pin member). The outer pin 16a constitutes the internal tooth of the internal gear 16. The number of internal teeth (the number of external pins 16a) of the internal gear 16 is slightly larger than the number of external teeth of the external gears 14 and 15 (only 1 in this example).
The end of the outer pin 16a on the input side is restricted from moving in the axial direction by the side surface on the opposite side of the fourth casing 22d, which will be described later.

The end of the outer pin 16a on the non-input side is restricted from moving in the axial direction by the side surface of the restricting washer 40 on the input side. The regulation washer 40 is a hollow disk-shaped member whose outer peripheral portion is sandwiched between the second casing 22b and the third casing 22c, which will be described later.

The carriers 18 and 20 are circular members. The first carrier 18 supports the end portion of the crank shaft 12 on the opposite side of the crank shaft 12 via the first crank shaft bearing 30. The first carrier 18 has a radial central hole 18h and a plurality of through holes 18p. The radial center hole 18h supports the first crank shaft bearing 30. A plurality of (for example, six) through holes 18p are provided at positions offset in the radial direction from the central axis La at predetermined intervals (for example, 60 °) in the circumferential direction.

The second carrier 20 supports the input-side end of the crank shaft 12 via the second crank shaft bearing 32. The second carrier 20 has a radial central hole 20h and a plurality of through holes 20p. The radial center hole 20h supports the second crank shaft bearing 32. A plurality of (for example, six) through holes 20p are provided at positions offset in the radial direction from the central axis La at predetermined intervals (for example, 60 °) in the circumferential direction.

The first carrier 18 and the second carrier 20 are connected by an inner pin 38 inserted through the through holes 18p and 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.

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 is a fixed member fixed to an external member for supporting the speed reducing device 100. Function. In the present 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 on the end face on the opposite side of the first carrier 18.

The inner pin 38 penetrates the inner pin holes 14h and 15h of the outer gears 14 and 15 in the axial direction at a position offset in the radial direction from the axis of the outer gears 14 and 15. In this example, a plurality of (for example, 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 inserted into the through hole 18p of the first carrier 18 from the counter-input side, passes through the inner pin holes 14h and 15h, and is fitted into the through hole 20p of the second carrier 20 to fit the first carrier 18 It is a connecting pin that connects the second carrier 20 and the second carrier 20.

A sleeve 38s is rotatably fitted to the outer periphery of the inner pin 38. The sleeve 38s is inserted with a gap in the inner pin holes 14h and 15h. The inner pin 38 comes into contact with a part of the inner pin holes 14h and 15h via the sleeve 38s. The inner pin 38 restrains the rotation of the external gears 14 and 15 and allows only the swing thereof. With this configuration, the carriers 18 and 20 move in synchronization with the rotation of the external gears 14 and 15 via the inner pin 38.

The casing 22 constitutes the outer shell of the speed reducer 100. The casing 22 includes a first casing 22a, a second casing 22b, a third casing 22c and a fourth casing 22d that are laminated in this order from the non-input side to 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 center in the radial direction.

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 and 15. An internal gear 16 is provided on the inner peripheral surface of the third casing 22c. The fourth casing 22d mainly covers the outer peripheral surface and the input side 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 second crank shaft bearing 32.

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

The main bearing 24 is arranged on the opposite side of the external gears 14 and 15. The main bearing 24 is arranged between the first carrier 18 and the casing 22. The configuration of the main bearing 24 is not limited, but the main bearing 24 in this example is a cross roller bearing. The outer ring of the main bearing 24 is integrally formed with the first casing 22a and the second casing 22b. The inner ring of the main bearing 24 is integrally formed with the carrier 18. The main bearing 24 rotatably supports the first carrier 18 with respect to the casing 22.

A characteristic configuration of the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 2 is a cross-sectional view showing the crank shaft 12. In order to increase the strength of the eccentric body bearings 34 and 36, it is conceivable to increase the diameter of the rollers 34a and 36a of the eccentric body bearings 34 and 36. However, if the diameter of the roller is simply increased, the size of the speed reducing device 100 is increased accordingly. Therefore, in the present embodiment, the first outer diameter D1 of the eccentric portions 12a and 12b of the crank shaft 12 is from the second outer diameter D2 of the shaft support portions 12c and 12d supported by the crank shaft bearings 30 and 32 of the crank shaft 12. Is also small. Since the first outer diameter D1 is small, it is possible to suppress the increase in size of the apparatus even if the rollers 34a and 36a are increased in diameter.

If the diameters of the eccentric portions 12a and 12b are reduced, the strength of the crank shaft 12 may decrease. In particular, there is a possibility that stress is concentrated on the corners (hereinafter referred to as “concave corners”) of the regions of the eccentric portions 12a and 12b that are recessed in the anti-eccentric direction. In the example of FIG. 2, in order to disperse the stress of the concave angle portion, the curved portion 12k is provided in the region of the eccentric portions 12a and 12b recessed in the anti-eccentric direction. In the region of the eccentric portions 12a and 12b in the anti-eccentric direction, the curved portion 12k has a first facing surface 12u facing the rollers 34a and 36a in the axial direction and a second facing surface 12v facing the rollers 34a and 36a in the radial direction. Is the part connected by a curve.

Further, curved surface portions 34k and 36k are provided at the axial end portions of the rollers 34a and 36a to avoid interference with the curved portion 12k. In addition to the R shape, the curved portion 12k and the curved surface portions 34k and 36k may have various shapes including a curved surface, a flat surface, and a composite surface of a curved surface and a flat surface. The shapes of the curved portion 12k and the curved surface portions 34k and 36k can be set by simulation according to the desired strength.

As shown in FIG. 2, in the rollers 34a and 36a of the eccentric body bearings 34 and 36, the outer diameter De at the axial end portion is smaller than the outer diameter Dc at the axial center portion. In this case, the rollers 34a and 36a can avoid interference with the curved portion 12k.

Preferably, the outer diameter De of the axial end portion of the rollers 34a, 36a may be 20% or less of the outer diameter Dc of the axial center portion of the rollers 34a, 36a. In this case, even when the radius of curvature of the curved portion 12k is large, it is possible to avoid interference with the curved portion 12k. Further, the axial end portions of the rollers 34a and 36a may not have a flat surface perpendicular to the axial direction (outer diameter De is zero). As an example, the axial end portions of the rollers 34a and 36a may be a spherical surface having a constant radius of curvature, a hemispherical surface, or a curved surface having a non-constant radius of curvature. In this case, the sliding resistance of the rollers 34a and 36a with the retaining portions 26, 27 and 28 can be reduced.

When the curved surfaces 34k and 36k are provided on the rollers 34a and 36a, there is a high possibility that the rollers 34a and 36a will come off to the crank shaft bearings 30 and 32. Further, since the sliding partner of the roller end face changes to the external gear, the eccentric portion, and the adjacent roller, it is disadvantageous in terms of life. In order to prevent the rollers from coming off, it is conceivable to integrally provide a flange portion having a diameter larger than the eccentric portion over the entire circumference of the outer circumference of the crank shaft. However, in this case, since the flange portion is integrated with the crank shaft, if the outer diameter of the flange portion is increased, it interferes with the center hole of the external gear and becomes difficult to assemble.

Therefore, in the present embodiment, in order to restrict the movement of the rollers 34a and 36a in the axial direction, the hollow disk-shaped retaining portions 26, 27, and 28 are separated from the crank shaft 12 and have an outer circumference of the crank shaft 12. Is placed in. With this configuration, it is possible to increase the diameter of the retaining portions 26, 27, and 28 while maintaining the assembling property, and it is possible to effectively prevent the rollers 34a and 36a from coming off.

In the present embodiment, the retaining portions 26, 27, and 28 are the first retaining portion 26 arranged between the first crank shaft bearing 30 and the first roller 34a, and the second crank shaft bearing 32 and the second roller 36a. It includes a second retaining portion 28 arranged between the first retaining portion 28 and an intermediate retaining portion 27 arranged between the first eccentric body bearing 34 and the second eccentric body bearing 36.

By having the first retaining portion 26, it is possible to restrict the movement of the first roller 34a to the first crank shaft bearing 30 side. By having the second retaining portion 28, it is possible to restrict the movement of the second roller 36a to the second crank shaft bearing 32 side. By having the intermediate retaining portion 27, mutual interference between the first roller 34a and the second roller 36a can be prevented. As shown in FIG. 1, the intermediate retaining portion 27 abuts on the external gears 14 and 15 when it is located in the anti-eccentric direction and when it is located in the eccentric direction. In this case, the intermediate retaining portion 27 comes into contact with the external gears 14 and 15 regardless of the swing position of the external gears 14 and 15, and the axial movement of the external gears 14 and 15 can also be restricted.

As shown in FIG. 1, in the present embodiment, the outer shapes of the retaining portions 26, 27, and 28 extend radially outward from the center lines L34 and L36 of the rollers 34a and 36a located in the eccentric direction. In this case, it is possible to more effectively prevent the rollers 34a and 36a from coming off.

As shown in FIG. 2, in the present embodiment, the first retaining portion 26 is fitted to the extension portion of the first shaft support portion 12c to the input side adjacent to the anti-input side of the first eccentric portion 12a, and is the second. 2 The retaining portion 28 is fitted to the extension portion of the shaft support portion 12d to the opposite input side adjacent to the input side of the second eccentric portion 12b. The intermediate retaining portion 27 fits into the eccentric region of the first eccentric portion 12a and the eccentric region of the second eccentric portion 12b.

The operation of the speed reducer 100 will be described. When the rotation is transmitted from the motor to the crank shaft 12, the eccentric portions 12a and 12b of the crank shaft 12 rotate around the rotation center line passing through the crank shaft 12, and the external gear 14 via the eccentric body bearings 34 and 36. 15 swings. When the external gears 14 and 15 swing, the meshing positions of the external gears 14 and 15 and the internal gear 16 are sequentially displaced. As a result, each time the crank shaft 12 makes one rotation, one of the external gears 14 and 15 and the internal gear 16 rotates by the amount corresponding to the difference in the number of teeth between the external gears 14 and 15 and the internal gear 16. Occur. In the present embodiment, the deceleration rotation is output from the first carrier 18 synchronized with the rotation of the external gears 14 and 15 via the inner pin 38.

The features of the speed reducer 100 configured in this way will be described. Since the speed reducing device 100 has a curved portion 12k in a region recessed in the anti-eccentric direction of the eccentric portion, stress concentration on this portion can be relaxed. Further, since the outer shape of the retaining portion can be enlarged, the axial movement of the rollers 34a and 36a can be restricted, and the lubricant of the eccentric portions 12a and 12b can be suppressed from leaking to the main bearing 24 side. Further, since the intermediate retaining portion 27 is provided, the sliding partner of the end faces of the rollers 34a and 36a does not change, which is advantageous in terms of life, and the lubricant of the eccentric portions 12a and 12b is the central hole 14c of the external gears 14 and 15. It is possible to suppress leakage from 15c.

Hereinafter, the second to fifth embodiments of the present disclosure will be described. In the drawings and description of the second to fifth embodiments, the same or equivalent components and members as those of the first embodiment are designated by the same reference numerals. The description overlapping with the first embodiment will be omitted as appropriate, and the configuration different from the first embodiment will be mainly described. Therefore, the description of the first embodiment is applied to the same or equivalent components and members as those of the first embodiment in the second to fifth embodiments.

[Second Embodiment]
The configuration of the eccentric swing type speed reducer 100 according to the second embodiment of the present disclosure will be described with reference to FIG. FIG. 3 is a cross-sectional view showing the overall configuration of the speed reducing device 100 according to the present embodiment.

The present embodiment is different from the first embodiment in that the second retaining portion 28 is integrally formed with the second carrier 20 and the crank shaft 12 is provided with the protrusion 12p corresponding to the second retaining portion 28. The configuration is common. Therefore, the protrusion 12p of the second retaining portion 28 and the crank shaft 12 will be mainly described.

In the example of FIG. 3, the second carrier 20 has a carrier main body portion 20b that supports the input side of the inner pin 38 and a hollow disk-shaped extension extending radially inward from the inner peripheral portion of the carrier main body portion 20b. It has a retaining portion 20c. The carrier main body portion 20b and the extension / removal stop portion 20c are integrally formed. The extension retaining portion 20c does not overlap with the center line L36 of the roller 36a (upper roller in the figure) located in the anti-eccentric direction when viewed from the axial direction, and is located in the eccentric direction 36a (lower side in the figure). It has an inner shape that overlaps with the center line L36 of the roller).

In the example of FIG. 3, the protrusion 12p is a substantially disk-shaped portion that protrudes outward in the radial direction from the extension portion of the second shaft support portion 12d to the opposite input side at the axial position corresponding to the extension / removal stop portion 20c. Is. When viewed from the axial direction, the protrusion 12p overlaps with the center line L36 of the roller 36a (upper roller in the figure) located in the anti-eccentric direction, and the center line of the roller 36a (lower roller in the figure) located in the eccentric direction. It does not overlap with L36.

This embodiment has the same effects and effects as those of the first embodiment.

[Third Embodiment]
With reference to FIG. 4, the configuration of the eccentric swing type speed reducer 100 according to the third embodiment of the present disclosure will be described. FIG. 4 is a cross-sectional view showing the overall configuration of the speed reducing device 100 according to the present embodiment.

This embodiment is different from the first embodiment in that the crank shaft 12 is provided with protrusions 12q and 12r corresponding to the first retaining portion 26, and other configurations are common. Therefore, the protrusions 12q and 12r of the crank shaft 12 will be mainly described.

In the example of FIG. 4, the protrusion 12q is a substantially disk-shaped portion that protrudes outward in the radial direction from the extension portion of the first shaft support portion 12c toward the input side at the axial position corresponding to the first retaining portion 26. be. The protrusion 12r is a substantially disk-shaped portion that protrudes outward in the radial direction from the extension portion of the second shaft support portion 12d to the counter-input side at the axial position corresponding to the second retaining portion 28. The outer shape of the protrusion 12q does not overlap with the center line L34 of the roller 34a located in the eccentric direction when viewed from the axial direction. Further, the inner shape of the first retaining portion 26 overlaps with the outer side of the protrusion 12q when viewed from the axial direction. The outer shape of the protrusion 12r does not overlap with the center line L36 of the roller 36a located in the eccentric direction when viewed from the axial direction. Further, the inner shape of the second retaining portion 28 overlaps with the outer side of the protrusion 12r when viewed from the axial direction.

This embodiment has the same effects and effects as those of the first embodiment.

[Fourth Embodiment]
With reference to FIG. 5, the configuration of the eccentric swing type speed reducer 100 according to the fourth embodiment of the present disclosure will be described. FIG. 5 is a cross-sectional view showing the overall configuration of the speed reducing device 100 according to the present embodiment.

The present embodiment is different from the first embodiment in that the inner diameter of the first retaining portion 26 is increased and the crank shaft 12 is provided with the protrusions 12s corresponding to the first retaining portion 26, and the other configurations are common. be. Therefore, the protrusion 12s of the crank shaft 12 will be mainly described.

In the example of FIG. 5, the protrusion 12s is a substantially disk-shaped portion that protrudes outward in the radial direction from the extension portion of the first shaft support portion 12c toward the input side at the axial position corresponding to the first retaining portion 26. be. The outer shape of the protrusion 12s of the present embodiment is larger than the outer shape of the protrusion 12q of the first embodiment. Further, the inner shape of the first retaining portion 26 of the present embodiment does not overlap with the protrusion 12s when viewed from the axial direction. Therefore, the first retaining portion 26 surrounds the outer periphery of the protrusion 12s with a gap.

This embodiment has the same effects and effects as those of the first embodiment.

The examples of the embodiments of the present invention have been described in detail above. All of the above-described embodiments are merely specific examples for carrying out the present invention. The contents of the embodiment do not limit the technical scope of the present invention, and many design changes such as changes, additions, and deletions of components are made within the range not deviating from the idea of the invention defined in the claims. It is possible. In the above-described embodiment, the contents that can be changed in design are described with the notations such as "in the embodiment" and "in the embodiment", but the design change is made to the contents without such notation. It's not unacceptable. Further, the hatching attached to the cross section of the drawing does not limit the material of the object to which the hatching is attached.

Hereinafter, a modified example will be described. In the drawings and description of the modified examples, the same or equivalent components and members as those in the embodiment are designated by the same reference numerals. The description that overlaps with the embodiment will be omitted as appropriate, and the configuration different from the embodiment will be mainly described.

[Modification example]
In the description of the embodiment, the example in which the casing 22 is composed of four members is shown, but the casing may be composed of three or less or five or more members.

In the description of the embodiment, an example in which the number of external gears is 2, but the number of external gears may be 1 or 3 or more.

As a pin member for connecting the carriers 18 and 20, a carrier pin that does not contribute to the transmission of the driving force may be provided separately from the inner pin 38.

Although the description of the embodiment shows an example in which the inner pin 38 is separate from the first carrier 18, the inner pin 38 may be formed integrally with the first carrier 18.

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

In the description of the embodiment, an example in which the speed reducing device 100 is a so-called center crank type planetary gear device is shown, but the present invention is not limited to this. The present invention can also be applied to, for example, an eccentric swing type speed reducer such as a distribution type.

Each of the above-mentioned modifications has the same operation and effect as that of the embodiment.

Any combination of the components of the embodiments described above and any of the modifications is also useful as embodiments of the present invention. The new embodiments resulting from the combination have the effects of the combined embodiments and variants.

12 Crank shaft, 12a 1st eccentric part, 12b 2nd eccentric part, 12c 1st shaft branch, 12d 2nd shaft branch, 12k curved part, 12p protrusion, 12u 1st facing surface, 12v 2nd facing surface, 14 1st External gear, 15 2nd external gear, 18 1st carrier, 20 2nd carrier, 22 Casing, 26 1st retaining part, 27 Intermediate retaining part, 28 2nd retaining part, 30 1st crank shaft bearing, 32nd 2 Crank shaft bearing, 34 1st eccentric body bearing, 34k curved surface part, 36 2nd eccentric body bearing, 34a, 36a roller, 100 eccentric swing type speed reducer.

Claims (8)

A crank shaft with an eccentric part and
A crank shaft bearing that supports the crank shaft and
An eccentric body bearing arranged radially outside the eccentric portion,
Equipped with
The eccentric body bearing is a full roller bearing.
The eccentric portion is recessed on the anti-eccentric direction side.
In the roller of the eccentric body bearing, the outer diameter of the outer end portion in the axial direction is smaller than the outer diameter of the central portion in the axial direction.
It has a retaining portion that is arranged on the outer circumference of the crank shaft and regulates the axial movement of the roller.
The eccentric swing type speed reducer, characterized in that the retaining portion is provided separately from the crank shaft. The crank shaft is a curved portion connected by a curve from a first facing surface facing the roller in the axial direction to a second facing surface facing the roller in the radial direction in a region in the anti-eccentric direction of the eccentric portion. The eccentric swing type speed reducer according to claim 1, further comprising. The eccentric swing type speed reducer according to claim 1 or 2, wherein the outer shape of the retaining portion extends radially outward from the center line of the roller located in the eccentric direction. The eccentric swing type speed reducer according to any one of claims 1 to 3, wherein the outer diameter of the axial end portion of the roller is 20% or less of the outer diameter of the axial center portion of the roller. .. The eccentric swing type speed reducer according to claim 4, wherein the axial end portion of the roller is a spherical surface. It has a carrier that synchronizes with the rotation of the external gear that swings with the rotation of the crank shaft.
The eccentric swing type speed reducing device according to any one of claims 1 to 5, wherein the retaining portion includes an extending retaining portion extending radially inward from the inner peripheral portion of the carrier. The eccentric body bearing includes a first eccentric body bearing and a second eccentric body bearing arranged apart from each other in the axial direction.
The eccentric swing type according to any one of claims 1 to 6, wherein the retaining portion includes an intermediate retaining portion arranged between the first eccentric body bearing and the second eccentric body bearing. Deceleration device. It has an external gear that swings with the rotation of the crank shaft.
The eccentric swing type speed reducing device according to claim 7, wherein the intermediate retaining portion regulates the axial movement of the external gear when it is located in the anti-eccentric direction and when it is located in the eccentric direction.

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