JP6736222B2 - Speed reducer and heat treatment method for rotating body - Google Patents

Description

The present invention relates to a speed reducer and a heat treatment method for a rotating body used in the speed reducer.

Patent Document 1 describes an eccentric rocking type reduction gear transmission. In this speed reducer, the rolling element is arranged between the eccentric body and the external gear, and the outer peripheral surface of the eccentric body constitutes the rolling surface of the rolling element.

JP, 2015-224707, A

Parts such as the eccentric body of Patent Document 1 that constitute the rolling surface of the rolling element are required to have high hardness on the rolling surface in order to improve fatigue strength. In order to realize this, conventionally, a heat treatment has been adopted for increasing the hardness of the entire work to be heat treated. However, no proposal has been made regarding the use of heat treatment in which both a high hardness region and a low hardness region appear in the work.

The present invention has been made in view of such circumstances, and an object thereof is to provide a technique capable of suitably adopting a heat treatment in which a high hardness region and a low hardness region appear in a work of a speed reducer component.

One aspect of the present invention relates to a speed reducer. The speed reducer includes an oscillating gear, an eccentric body that is a rotating body that oscillates the oscillating gear, and a rolling element that is arranged between the oscillating gear and the eccentric body. Is an eccentric oscillating speed reducer in which an outer peripheral surface of the eccentric body constitutes a rolling surface of the rolling element, and the outer peripheral surface of the eccentric body has a first high hardness region and a surface hardness higher than that of the first high hardness region. A low first low hardness region is provided, and the first low hardness region is within a range of ±90 degrees from a reference line extending in an anti-maximum eccentric direction from the shaft center in a range around the shaft center of the eccentric body. It is provided in.

Another aspect of the present invention also relates to a reduction gear transmission. The speed reducer includes a flexible external gear, a vibration body that is a rotating body that flexibly deforms the external gear and has an elliptical cross section perpendicular to the axis, and between the external gear and the vibration body. And a rolling element disposed on the outer peripheral surface of the vibrating body, the outer peripheral surface of the vibrating body being a rolling surface of the rolling element. A high-hardness region and a first low-hardness region having a surface hardness lower than that of the first high-hardness region are provided, and the first low-hardness region is the rotation center of the range around the rotation center of the vibrator. Further, it is provided within a range of ±45 degrees from the reference line extending along the minor axis direction of the vibrating body.

Another aspect of the present invention relates to a method for heat treating a rotating body. The present method is a method for heat treating a rotating body which is an eccentric body of an eccentric oscillating reduction gear, wherein the eccentric body oscillates an oscillating gear and is arranged between the eccentric body and the oscillating gear. The rolling surface is constituted by the outer peripheral surface, and includes a heat treatment step of heat-treating the outer peripheral surface of the eccentric body by irradiating a laser beam from the head, and in the heat treating step, the irradiation position of the laser light of the outer peripheral surface is By changing along the circumferential direction, after quenching the outer peripheral surface over the entire circumference, re-irradiate the laser light to a part of the range that has been irradiated with the laser light, the laser to the outer peripheral surface The re-irradiation range of light is set so as to be within ±90 degrees from the reference line extending in the direction of the anti-maximum eccentric direction from the axis of the range around the axis of the eccentric body.

Another aspect of the present invention relates to a method for heat treating a rotating body. This method is a method for heat treatment of a rotating body that is a vibrating body of a flexible mesh type speed reducer, wherein the vibrating body rotates an external gear having flexibility and has an elliptical cross section perpendicular to the axis. An outer peripheral surface constitutes a rolling surface of a rolling element arranged between the external gear and the heat treatment step of heat-treating the outer peripheral surface of the vibrating body by irradiating a laser beam from a head, In the heat treatment step, by changing the irradiation position of the laser light with respect to the outer peripheral surface along the circumferential direction of the outer peripheral surface, after quenching the outer peripheral surface over the entire circumference, the range of irradiation of the laser light has been completed. The laser beam is re-irradiated to a part, and the re-irradiation range of the laser beam to the outer peripheral surface is within the range around the rotation center line of the vibration exciter, from the rotation center line to the vibration exciter. It is set to fall within a range of ±45 degrees from the reference line extending along the minor axis direction.

According to the present invention, it is possible to preferably employ a heat treatment in which a high hardness region and a low hardness region appear on a work of a speed reducer component.

It is sectional drawing which shows the reduction gear of 1st Embodiment. It is sectional drawing which expands and shows the eccentric body and eccentric body bearing of 1st Embodiment. It is the perspective view which looked at each eccentric body of a 1st embodiment from the front upper part. It is the perspective view which looked at each eccentric body of a 1st embodiment from the back lower side. It is a side view of each eccentric body of the first embodiment. It is a top view of each eccentric body of the first embodiment. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is a figure for demonstrating the heat processing method of the eccentric body of 1st Embodiment. It is sectional drawing which shows the reduction gear of 2nd Embodiment. It is a figure which shows the outer peripheral surface in the cross section orthogonal to the axial direction of the vibrating body of 2nd Embodiment.

Hereinafter, in the embodiments and the modified examples, the same reference numerals are given to the same components, and the duplicated description will be omitted. Further, in each drawing, for convenience of description, some of the constituent elements are omitted as appropriate, and the dimensions of the constituent elements are appropriately enlarged or reduced. In addition, different constituent elements having common points are distinguished by adding "first and second" or the like at the beginning of the name and adding "-A, -B" or the like at the end of the reference numerals. When these are omitted.

(First embodiment)
FIG. 1 is a sectional view showing a speed reducer 10 of the first embodiment. The speed reducer 10 of the present embodiment is an eccentric rocking type speed reducer that rotates an oscillating gear that meshes with a meshing gear by an eccentric body to rotate the oscillating gear and to output its rotation component. The speed reducer 10 of the present embodiment is an external gear oscillating speed reducer in which the mesh gear is the internal gear 22 and the oscillating gear is the external gear 20.

The reduction gear transmission 10 mainly includes a casing 12, an input shaft 14, an eccentric body 16, an eccentric body bearing 18, an external gear 20, an internal gear 22, and a carrier 24.

Inside the casing 12, the eccentric body 16 and other internal components of the reduction gear transmission 10 are housed.

The input shaft 14 is rotationally driven by a drive shaft of a drive device such as a motor. The input shaft 14 rotates about its own axis. The input shaft 14 of this embodiment is integrated with the drive shaft.

The eccentric body 16 is provided so as to be integrally rotatable with the input shaft 14 via a key or the like. The eccentric body 16 swings the external gear 20 by rotating around the rotation center line Lc passing through the rotation center of the input shaft 14.

FIG. 2 is an enlarged sectional view showing the eccentric body 16 and the eccentric body bearing 18. The eccentric body 16 of the present embodiment includes a first eccentric body 16-A and a second eccentric body 16-B that are adjacent to each other in the axial direction along the rotation center line Lc. The eccentric body bearing 18, the external gear 20, and the internal gear 22 are individually provided corresponding to each of the first eccentric body 16-A and the second eccentric body 16-B. The corresponding components are distinguished by adding "first and second" at the beginning of the name and adding "-A, -B" at the end of the reference numeral. Details of the eccentric body 16 will be described later.

The eccentric body bearing 18 has a plurality of rolling elements 26 and a retainer 28. The eccentric body bearing 18 is axially positioned by a stopper or the like (not shown). The retainer 28 holds the relative positions of the plurality of rolling elements 26 and rotatably supports the plurality of rolling elements 26.

The rolling element 26 is arranged between the external gear 20 and the eccentric body 16, that is, between the oscillating gear and the eccentric body 16. The rolling elements 26 are provided at intervals in the circumferential direction around the rotation center line Lc. The rolling element 26 of this embodiment is a roller. Specifically, the rolling element 26 is a cylindrical roller having a rotation axis parallel to the rotation center line Lc.

The eccentric body bearing 18 of the present embodiment does not have a dedicated inner ring and outer ring. Instead, the outer peripheral surface of the eccentric body 16 functions as an inner ring, and the inner peripheral surface of a through hole 20a (described later) of the external gear 20 functions as an outer ring. That is, the outer peripheral surface of the eccentric body 16 constitutes the inner rolling surface 30 on which the rolling body 26 rolls in the circumferential direction. Further, the inner peripheral surface of the external gear 20 constitutes an outer rolling surface on which the rolling elements 26 roll in the circumferential direction.

Returning to FIG. The external gear 20 is provided so as to be swingable around the rotation center line Lc by the eccentric body 16 via the rolling body 26. The external gear 20 internally meshes with the internal gear 22 while swinging. A through hole 20a penetrating in the axial direction is formed in the external gear 20, and an eccentric body 16 and a rolling element 26 are arranged inside the through hole 20a. A plurality of pin holes 20b are formed in the external gear 20. The pin holes 20b are provided at intervals in the circumferential direction at positions radially offset from the rotation center line Lc. The inner pin 32 is loosely fitted in each pin hole 20b. An inner roller 34 is rotatably attached to the outer peripheral side of the inner pin 32.

The internal gear 22 of the present embodiment is rotatably mounted on the internal gear main body 36 integrated with the casing 12, the external pin 38 supported by the internal gear main body 36, and the outer peripheral side of the external pin 38. And an outer roller 40. The outer roller 40 constitutes the internal teeth of the internal gear 22. The number of internal teeth of the internal gear 22 (the number of outer rollers 40) is one more than the number of external teeth of the external gear 20 in the present embodiment.

The carrier 24 is arranged axially on one side of the external gear 20. The carrier 24 can rotate in synchronization with the rotation component of the external gear 20. In order to realize this, the carrier 24 is formed with a pin holding hole 24a into which the inner pin 32 is press-fitted, and the rotation component of the external gear 20 is transmitted via the inner pin 32. The carrier 24 is integrated with an output shaft 44 rotatably supported by the casing 12 via an output bearing 42.

The operation of the speed reducer 10 described above will be described. When the drive shaft rotates, the input shaft 14 rotates together with the drive shaft. When the input shaft 14 rotates, the eccentric body 16 rotates together with the input shaft 14 around the rotation center line Lc. When the eccentric body 16 rotates about the rotation center line Lc, the external gear 20 swings via the rolling elements 26. When the external gear 20 swings, the meshing positions of the external gear 20 and the internal gear 22 are sequentially displaced. As a result, the external gear 20 rotates relative to the internal gear 22, that is, rotates, by an amount corresponding to the difference in the number of teeth with the internal gear 22 each time the input shaft 14 makes one rotation. The rotation component of the external gear 20 is transmitted to the carrier 24 via the inner roller 34 and the inner pin 32, and is transmitted to the output shaft 44 integrated with the carrier 24. As a result, the rotation of the input shaft 14 is decelerated at a reduction ratio corresponding to the tooth number difference between the external gear 20 and the internal gear 22 and the number of teeth of the oscillating gear, and is output from the output shaft 44.

FIG. 3 is a perspective view of each eccentric body 16 as viewed from the front upper side. FIG. 4 is a perspective view of each eccentric body 16 as viewed from the lower rear side. FIG. 5 is a side view of the eccentric body 16. FIG. 6 is a top view of the eccentric body 16. In this figure, the first low hardness region 50 and the second low hardness region 54, which will be described later, are hatched. As described above, the eccentric body 16 includes the first eccentric body 16-A and the second eccentric body 16-B. The first eccentric body 16-A is a first rotating body that swings the first external gear 20-A, and the second eccentric body 16-B is a second rotating body that swings the second external gear 20-B. It is the body. An eccentric body connecting portion 46 is provided between the first eccentric body 16-A and the second eccentric body 16-B to connect them. The first eccentric body 16-A, the second eccentric body 16-B, and the eccentric body connecting portion 46 are integrally molded products that are integrally molded. This integrally molded product is obtained by cutting or the like. This integrally molded product is made of steel such as high carbon chrome steel, that is, metal.

FIG. 7 is a cross-sectional view taken along the line AA of FIG. In this figure, the eccentric body bearing 18 is also shown. The eccentric body 16 has a cylindrical shape, and the outer peripheral surface thereof has a circular shape in the present embodiment. The outer peripheral surface of the eccentric body 16 is eccentric with respect to the rotation center line Lc by a predetermined eccentric amount e. The maximum eccentric direction Pa of the first eccentric body 16-A and the second eccentric body 16-B is 180 degrees out of phase around the rotation center line Lc. The maximum eccentric direction Pa of the eccentric body 16 here means a direction in which the eccentric amount e is generated from the rotation center line Lc. From another point of view, the maximum eccentric direction Pa means a direction extending from the rotation center line Lc of the eccentric body 16 to the axial center Cp of the eccentric body 16. The axis Cp of the eccentric body 16 here means the center of gravity of the shape formed by the outer peripheral surface of the eccentric body 16 in a cross section orthogonal to the axial direction of the eccentric body 16. In the present embodiment, since the outer peripheral surface of the eccentric body 16 has a circular shape, the center of the circular shape is the axis Cp of the eccentric body 16.

FIG. 8 is a sectional view taken along line BB of FIG. As shown in FIGS. 5 and 8, the eccentric body connecting portion 46 has a tubular shape having an outer shape different from that of the first eccentric body 16-A and the second eccentric body 16-B. The eccentric body connecting portion 46 includes a first outer peripheral surface portion 46a axially continuous with the outer peripheral surface of the first eccentric body 16-A, and a second outer peripheral surface portion axially continuous with the outer peripheral surface of the second eccentric body 16-B. 46b. The first outer peripheral surface portion 46a constitutes one half peripheral surface portion of the two half peripheral surface portions constituting the entire outer peripheral surface of the eccentric body connecting portion 46, and the second outer peripheral surface portion 46b constitutes the other half peripheral surface portion. The outer peripheral surface of the eccentric body connecting portion 46 is constituted by a combination of the first outer peripheral surface portion 46a and the second outer peripheral surface portion 46b over the entire circumference.

A curvature changing portion 46c is provided at a boundary portion between the first outer peripheral surface portion 46a and the second outer peripheral surface portion 46b. The curvature changing portion 46c is a boundary where the curvature of the first outer peripheral surface portion 46a changes to the curvature of the second outer peripheral surface portion 46b in the cross section orthogonal to the axial direction of the eccentric body connecting portion 46. The curvature changing portion 46c has an angular shape that is convex outward. The curvature changing portion 46c extends from the second eccentric body 16-B toward the first eccentric body 16-A from the first outer peripheral surface portion 46a toward the second outer peripheral surface portion 46b.

Here, a first high hardness region 48 and a first low hardness region 50 are provided on the outer peripheral surface of each eccentric body 16. In FIGS. 3 to 6, the non-hatched portion of the outer peripheral surface of the eccentric body 16 is the first high hardness region 48, and the hatched portion is the first low hardness region 50. In this embodiment, one eccentric body 16 is provided with one first high-hardness region 48, and other eccentric bodies 16 are provided with a first low-hardness region 50. The first low hardness region 50 is a region whose surface hardness is lower than that of the first high hardness region 48. The surface hardness here means the hardness of the surface layer portion including the outer peripheral surface of the eccentric body 16. Specifically, the total hardness measured for each predetermined unit depth (for example, 0.1 mm) with respect to a predetermined range (for example, 1.0 mm) in the depth direction (normal direction) from the outer peripheral surface of the eccentric body 16. The average value of The hardness difference between the first high hardness region 48 and the first low hardness region 50 is, for example, a range of at least 50 Hv or more in Vickers hardness. This hardness difference is usually in the range of 150 Hv or more when the heat treatment by laser hardening described later is performed as in the present embodiment.

The first high hardness region 48 is obtained by quenching the material of the eccentric body 16 by laser quenching or the like, as described later. In the surface layer portion of the first high hardness region 48, for example, a quenched structure having martensite or the like as a main phase is provided. The first low hardness region 50 is obtained by quenching the same portion when quenching the material of the eccentric body 16 by laser quenching or the like, as described later. In the surface layer portion of the first low hardness region 50, for example, a tempered structure having a mixed structure of ferrite and austenite as a main phase is provided.

In the present embodiment, as shown in FIG. 7, the non-load range Sa is defined as the range in which the first low hardness region 50 should be provided. The non-load range Sa is a range of ±90 degrees from the first reference line Lb1 extending in the anti-maximum eccentric direction Pb from the axis Cp of the eccentric body 16 in the range around the axis Cp of the eccentric body 16. Here, the anti-maximum eccentric direction Pb means a direction that extends diametrically opposite to the maximum eccentric direction Pa across the rotation center line Lc. The non-load range Sa is individually set for each of the first eccentric body 16-A and the second eccentric body 16-B. Since the first eccentric body 16-A and the second eccentric body 16-B are out of phase with each other by 180 degrees, the non-load range Sa of the second eccentric body 16-B is not shown, but the first eccentric body 16-A is not shown. It is provided at a position 180 degrees out of phase with the non-load range Sa of −A. The first low hardness region 50 is provided so as to be entirely within this non-load range Sa. The reason for this will be explained.

When the eccentric body 16 is rotated in the positive direction (clockwise direction in the drawing), the eccentric body 16 has the maximum distance from the rolling element 26 to any position within a range Sb of −90 degrees from the second reference line Lb2 extending in the maximum eccentric direction Pa. Load is added, and almost no load is applied to other areas. Further, when the eccentric body 16 rotates in the opposite direction (counterclockwise direction in the drawing), the rolling element 26 is located at any position within the range Sc of +90 degrees from the second reference line Lb2 extending in the maximum eccentric direction Pa. The maximum load is applied from, and almost no load is applied to other ranges. That is, the eccentric body 16 receives almost no load in the non-load range Sa of ±90 degrees from the first reference line Lb1 extending in the anti-maximum eccentric direction Pb regardless of the rotation direction of the eccentric body 16.

If the first low hardness region 50 is provided in the non-load range Sa, a large load is not applied to the first low hardness region 50, and the life of the eccentric body 16 is shortened due to the first low hardness region 50. It can be prevented. Therefore, even if the heat treatment (for example, laser hardening) in which the high hardness region and the low hardness region appear in the work of the rotating body (eccentric body 16) which is a component for the speed reducer, the service life is shortened due to the low hardness region. The effect can be eliminated. Therefore, according to the present embodiment, it is possible to preferably adopt the heat treatment in which the high hardness region and the low hardness region appear in the work of the speed reducer component.

The first low hardness region 50 is preferably provided in the range Sd in the vicinity of the first reference line Lb1 on the outer peripheral surface of the eccentric body 16. The range Sd is a range of ±30 degrees from the first reference line Lb1. In this range Sd, when the eccentric body 16 rotates, it is difficult for a load to be particularly applied to the eccentric body 16 from the rolling elements 26. Therefore, by providing the first low hardness region 50 in this range Sd, it is possible to more effectively prevent the reduction in the life due to the first low hardness region 50.

Other features of the speed reducer 10 will be described.
As shown in FIG. 6, the first low hardness region 50 is provided in a range over the entire axial length of each eccentric body 16. The first low hardness region 50 extends in the axial direction of the eccentric body 16 and has a strip shape that is inclined with respect to the axial direction of the eccentric body 16.

Consider a contact line Ld between the rolling surface 30 of the eccentric body 16 and the rolling body 26. The contact line Ld is a portion where the rolling surface 30 and the rolling element 26 linearly contact each other when the rolling element 26 rolls on the rolling surface 30 of the eccentric body 16. At this time, the width and inclination angle of the strip formed by the first low hardness region 50 are such that when the contact line Ld passes over the first low hardness region 50, the contact line Ld also passes over the first high hardness region 48. Is set. That is, the contact line Ld is set so as not to pass over only the first low hardness region 50 but pass through both the first high hardness region 48 and the first low hardness region 50.

This condition is satisfied in all circumferential ranges in which the contact line Ld can pass over the first low hardness region 50, in the circumferential range of the rolling surface 30. This condition becomes easier to satisfy as the width of the band becomes narrower or the inclination angle of the band becomes larger. The width of this band does not need to be constant over the entire length of the eccentric body 16 in the axial direction, and may vary depending on the position in the axial direction. The width here means a dimension along the circumferential direction of the eccentric body 16. The inclination angle here means an inclination formed by the longitudinal direction of the strip with respect to the axial direction of the eccentric body 16 when the strip formed by the first low hardness region 50 is developed on the flat surface on the outer peripheral surface of the eccentric body 16. Says the angle.

Thereby, when the rolling element 26 contacts the first low hardness area 50 of the eccentric body 16, the rolling element 26 can also contact the first high hardness area 48. Therefore, compared with the case where the rolling elements 26 contact only the first low hardness region 50 of the eccentric body 16, the load on the first low hardness region 50 of the eccentric body 16 can be suppressed and the life of the eccentric body 16 can be extended. You can

Please refer to FIG. 3 to FIG. A second high hardness region 52 and a second low hardness region 54 are provided on the outer peripheral surface of the eccentric body connecting portion 46. 3 to 6, the non-hatched portion of the outer peripheral surface of the eccentric body connecting portion 46 is the second high hardness region 52, and the hatched portion is the second low hardness region 54. The relationship between the second high hardness region 52 and the second low hardness region 54 is the same as the relationship between the first high hardness region 48 and the first low hardness region 50. That is, the second low hardness region 54 is a region having a lower surface hardness than the second high hardness region 52. The surface hardness here means the hardness of the surface layer portion including the outer peripheral surface of the eccentric body connecting portion 46, and is as described above. The hardness difference between the second high hardness region 52 and the second low hardness region 54 is, for example, a range of at least 50 Hv or more in Vickers hardness. This hardness difference is usually in the range of 150 Hv or more when the heat treatment by laser hardening described later is performed as in the present embodiment.

The second low hardness region 54 includes a first region portion 54a, a second region portion 54b, and a third region portion 54c. The first region portion 54a is axially continuous with the first low hardness region 50 of the first eccentric body 16-A. The first region portion 54a is provided in the central portion in the circumferential direction of the first outer peripheral surface portion 46a of the eccentric body connecting portion 46, that is, in the intermediate portion in the circumferential direction. The second region portion 54b is axially continuous with the first low hardness region 50 of the second eccentric body 16-B. The second region portion 54b is provided in the central portion in the circumferential direction of the second outer peripheral surface portion 46b of the eccentric body connecting portion 46, that is, in the intermediate portion in the circumferential direction.

The third region portion 54c is provided at a boundary portion between the first outer peripheral surface portion 46a and the second outer peripheral surface portion 46b of the eccentric body connecting portion 46. Specifically, the third region portion 54c is provided in each of the one boundary portion between the first outer peripheral surface portion 46a and the second outer peripheral surface portion 46b of the eccentric body connecting portion 46 and the other boundary portion. The curvature changing portion 46c is provided at this boundary portion, and the third region portion 54c is provided along the curvature changing portion 46c.

Such an eccentric body connecting portion 46 is, as described later, a heat treatment step for providing the first high hardness region 48 on the outer peripheral surface of the first eccentric body 16-A, and the outer peripheral surface of the second eccentric body 16-B. It can be obtained by going through two steps including a heat treatment step for providing the first high hardness region 48. That is, the heat treatment step for increasing the hardness of the eccentric body connecting portion 46 does not have to be performed separately from the heat treatment step for the first eccentric body 16-A and the second eccentric body 16-B. Therefore, with respect to the component having the plurality of eccentric bodies 16, it is possible to use a component having a high hardness in at least the number of heat treatment steps.

Please refer to FIG. A hollow portion 56 and a first lubricating oil passage 58 are provided inside the eccentric body 16. The hollow portion 56 extends in the axial direction, and the input shaft 14 is inserted into the hollow portion 56. A part of the hollow portion 56 of the eccentric body 16 is arranged at a position lower than the oil level of the lubricating oil sealed in the casing 12 in a stationary state. This lubricating oil may be oil or grease.

The first lubricating oil passage 58 extends in the radial direction from the hollow portion 56 and has a blowout port 58 a that opens to the outer peripheral surface of the eccentric body 16. When the eccentric body 16 rotates, the lubricating oil enters the first lubricating oil passage 58 through the inside of the hollow portion 56 of the eccentric body 16. The lubricating oil flows between the hollow portion 56 of the eccentric body 16 and the input shaft 14 or through a second lubricating oil passage (not shown) formed in the input shaft 14 and extending in the axial direction. Enter the road 58. When the eccentric body 16 rotates in this state, centrifugal force acts on the lubricating oil in the first lubricating oil passage 58. As a result, the lubricating oil in the hollow portion 56 of the eccentric body 16 is sucked into the first lubricating oil passage 58, and the lubricating oil is blown out from the outlet 58a of the first lubricating oil passage 58, so that the eccentric body bearing 18 and surrounding parts Are lubricated with lubricating oil.

Here, the air outlet 58a of the first lubricating oil passage 58 is open to the first low hardness region 50 of the eccentric body 16, as shown in FIGS. 3, 4, and 6. The blowout port 58a has a shape that entirely fits in the first low hardness region 50 and is not formed in the first high hardness region 48. Therefore, the opening edge of the air outlet 58a has a low hardness, so that it is easier to ensure durability than the opening of the air outlet 58a in the first high hardness region 48. Further, the work for providing the air outlet 58a on the outer peripheral surface of the eccentric body 16 is easier than the air outlet 58a opening in the first high hardness region 48, and good workability can be obtained.

Next, a method of heat-treating the eccentric body 16 described above will be described.
FIG. 9 is a diagram for explaining a heat treatment method for the eccentric body 16. In this embodiment, heat treatment is performed by laser hardening using laser light. When laser quenching is used, there are advantages such that cooling equipment for quenching is unnecessary, environmental load is small, and heat treatment distortion is small.

The eccentric body 16 that is the workpiece to be heat-treated is supported by a rotating jig (not shown) so as to be rotatable around the axis Cp. In this state, the outer peripheral surface of the eccentric body 16 is quenched by irradiating the laser light 62 from the head 60.

The eccentric body 16 is heat-treated separately in the first heat treatment step of the first eccentric body 16-A and the second heat treatment step of the second eccentric body 16-B. In the first heat treatment step, as shown in FIG. 9A, the range over the entire axial length of the outer peripheral surface of the first eccentric body 16-A and the axial direction of the first outer peripheral surface portion 46 a of the eccentric body connecting portion 46. The laser light 62 is applied to the range over the entire length of the. In the same process, by changing the irradiation position of the laser beam to the first eccentric body 16-A along the circumferential direction of the first eccentric body 16-A, the outer peripheral surface of the first eccentric body 16-A is made to be the entire circumference. Quench in one process. In order to realize this, the radial direction position of the head 60 with respect to the first eccentric body 16-A is not changed, and the first eccentric body 16-A is rotated around its own axis Cp by a rotating jig. As a result, the laser beam is emitted while the distance from the head 60 to the irradiation position on the first eccentric body 16-A (hereinafter referred to as the irradiation distance) is substantially constant. By this one-process quenching, not only the outer peripheral surface of the first eccentric body 16-A but also the first outer peripheral surface portion 46a of the eccentric body connecting portion 46 is quenched.

In the second heat treatment step, as shown in FIG. 9B, the range over the entire axial length of the outer peripheral surface of the second eccentric body 16-B and the total length of the second outer peripheral surface portion 46b of the eccentric body connecting portion 46 are determined. The laser beam 62 is applied to the range. Also in the same process, by changing the irradiation position of the laser beam to the second eccentric body 16-B along the circumferential direction of the second eccentric body 16-B, the outer peripheral surface of the second eccentric body 16-B is made to be the entire circumference. Quench in one process. In order to realize this, the second eccentric body 16-B is rotated around its own axis Cp by a rotating jig. This one-process quenching quenches not only the outer peripheral surface of the second eccentric body 16-B but also the second outer peripheral surface portion 46b of the eccentric body connecting portion 46.

In both cases of the first heat treatment step and the second heat treatment step, by changing the irradiation position of the laser light on the eccentric body 16 along the circumferential direction, after quenching the outer peripheral surface of the eccentric body 16 over the entire circumference, The laser light is irradiated again to a part of the area which has been irradiated with the laser light. As a result, the first low hardness region 50 called a soft zone is provided in the re-irradiation range of the laser light by tempering.

The re-irradiation range of the laser light on the outer peripheral surface of the eccentric body 16 is, for example, a range of several mm from the irradiation start position of the laser light on the eccentric body 16. This re-irradiation range is set so as to be within the non-load range Sa of the eccentric body 16 described above. That is, the re-irradiation range falls within ±90 degrees from the first reference line Lb1 extending in the anti-maximum eccentric direction Pa from the axis Cp of the eccentric body 16 in the range around the axis Cp of the eccentric body 16. Is set to. As a result, the first low hardness region 50 is provided in the non-load range Sa of the eccentric body 16, and the first high hardness region 48 is provided in the other range of the outer peripheral surface of the eccentric body 16.

In any of the first heat treatment step and the second heat treatment step, the position of the head 60 and the laser irradiation angle from the head 60 are set so that the above-mentioned soft zone has a strip shape inclined with respect to the axial direction of the eccentric body 16. Has been adjusted. Thereby, the first low-hardness region 50 in the form of a band is provided which is inclined with respect to the axial direction of the eccentric body 16.

When the first eccentric body 16-A is rotated around the axis Cp in the first heat treatment step, the irradiation distance from the head 60 to the first eccentric body 16-A and the first distance from the head 60 to the eccentric body connecting portion 46 are determined. The irradiation distance to the outer peripheral surface portion 46a is equal regardless of the rotational position of the first eccentric body 16-A. On the other hand, the irradiation distance from the head 60 to the second outer peripheral surface portion 46b of the eccentric body connecting portion 46 is the irradiation distance to the above-mentioned first eccentric body 16-A or the first outer peripheral surface portion 46a of the eccentric body connecting portion 46. It is smaller than the irradiation distance. As a result, in the eccentric body connecting portion 46, the entire first outer peripheral surface portion 46a is quenched and the second outer peripheral surface portion 46b is not quenched. At this time, the first outer peripheral surface portion 46a is quenched in a range including the curvature changing portions 46c on both sides in the circumferential direction.

When the second heat treatment step is performed on the intermediate processed product thus obtained, the entire second outer peripheral surface portion 46b of the eccentric body connecting portion 46 is quenched. At this time, the curvature changing portion 46c of the second outer peripheral surface portion 46b is re-irradiated. As a result, the third region portion 54c of the second low hardness region 54 is provided in the curvature changing portion 46c of the eccentric body connecting portion 46 and the peripheral portion.

(Second embodiment)
FIG. 10 is a cross-sectional view showing the reduction gear transmission 10 of the second embodiment. The speed reducer 10 of the present embodiment is a flexural engagement type speed reducer that rotates the external gear 120 that meshes with the internal gear 122 while flexibly deforming the external gear 120 to rotate and output the rotation component thereof.

The reduction gear transmission 10 mainly has a casing 112, a pair of carriers 114, a vibrating body 116, a vibrating body bearing 118, an external gear 120, and an internal gear 122.

The casing 112 is a cylindrical member, and a pair of carriers 114 are arranged inside thereof. The pair of carriers 114 are rigid cylindrical members, and the vibrating body 116 is arranged inside thereof. The pair of carriers 114 are arranged at intervals in the axial direction of the vibrating body 116. One carrier 114-A (the carrier on the right side in the figure; hereinafter referred to as the input-side carrier 114-A) is non-rotatably assembled to the casing 112, and a bolt (not shown) screwed into the bolt hole 114a causes a motor or the like to rotate. Connected to a drive. The other carrier 114-B (the left carrier in the figure; hereinafter referred to as the output carrier 114-B) is rotatably supported by the casing 112 via a main bearing 124. The output side carrier 114-B functions as an output unit for outputting the rotation input from the drive device.

The vibrating body 116 is a tubular member, and its cross-sectional shape perpendicular to the axis is formed in an elliptical shape. In the present application, the ellipse is not limited to a geometrically strict elliptical shape and includes a substantially elliptical shape having a major axis and a minor axis. The vibrating body 116 is rotatably supported by the pair of carriers 114 via bearings 126. The drive shaft of the drive device is connected to the vibrating body 116. The vibrating body 116 functions as an input shaft that is rotationally driven by its drive shaft about its own axis. The vibrating body 116 also functions as a rotating body that flexibly deforms the external gear 120.

The vibration body bearing 118 is arranged between the vibration body 116 and the external gear 120. The vibrating body bearing 118 includes a first vibrating body bearing 118-A that rotatably supports a first external tooth portion 120b (described later) of the external gear 120, and a second external tooth portion 120c of the external gear 120. A second vibrator bearing 118-B that rotatably supports (described later) is included.

The vibration element bearing 118 has a plurality of rolling elements 128, a retainer 130, and an outer ring 132. The retainer 130 holds the relative positions of the rolling elements 128 and rotatably supports the rolling elements 128. The outer ring 132 is arranged on the outer peripheral side of the plurality of rolling elements 128. The outer ring 132 has flexibility and, like the external gear 120, is flexibly deformed into an elliptical shape by the vibrating body 116 via the plurality of rolling elements 128.

The rolling element 128 is arranged between the vibration generator 116 and the external gear 120. The rolling elements 128 are provided at intervals in the circumferential direction around the rotation center line Le extending along the rotation center of the vibration generating body 116. The rolling element 128 of this embodiment is a roller. Specifically, the rolling element 128 is a cylindrical roller having a rotation axis parallel to the rotation center line Le.

The vibrating body bearing 118 of this embodiment does not have a dedicated inner ring. Instead, the outer peripheral surface of the vibrating body 116 functions as an inner ring. The outer peripheral surface of the vibrating body 116 constitutes an inner rolling surface 134 on which the rolling body 128 rolls. Specifically, the outer peripheral surface of the vibrating body 116 has a first inner rolling surface 134-A on which the first rolling element 128-A of the first vibrating body bearing 118-A rolls, and a second vibrating body bearing. 118-B has a second inner rolling surface 134-B on which the second rolling element 128-B rolls. The first inner rolling surface 134-A and the second inner rolling surface 134-B are continuous in the axial direction and have the same sectional shape.

The external gear 120 is arranged on the outer peripheral side of the vibrator 116. The external gear 120 is a flexible annular member. The external gear 120 is bent and deformed into an elliptical shape by the vibrating body 116 via the plurality of rolling elements 128. The external gear 120 is internally meshed with the internal gear 122 on both sides of the vibrating body 116 in the long axis direction. The external gear 120 has a cylindrical base portion 120a, and a first external tooth portion 120b and a second external tooth portion 120c that are integrally formed on the outer peripheral side of the base portion 120a. The first outer tooth portion 120b is arranged on one side in the axial direction, and the second outer tooth portion 120c is arranged on the other side in the axial direction. When the vibrator 116 rotates, the external gear 120 is flexibly deformed so as to match the shape of the vibrator 116 while changing the meshing position with the internal gear 122 in the circumferential direction.

The internal gear 122 is an annular member having rigidity. The internal gear 122 is arranged on the outer peripheral side of the external gear 120. The internal gear 122 has a first internal gear 122-A in which the first external gear 120b of the external gear 120 internally meshes, and a second external gear 120c of the external gear 120 internally meshes. 2 Internal gear 122-B is included. The first internal gear 122-A has more internal teeth by 2i (i is a natural number of 1 or more) than the number of external teeth of the first external gear 120b, and the second internal gear 122-B has the second external gear 122-B. The number of internal teeth is the same as the number of external teeth of the tooth portion 120c. The first internal gear 122-A is integrally formed with the input side carrier 114-A, and the second internal gear 122-B is integrally formed with the output side carrier 114-B.

The operation of the speed reducer 10 described above will be described.
When the drive shaft rotates, the vibrating body 116 rotates together with the drive shaft. When the vibrating body 116 rotates, the external gear 120 is continuously flexibly deformed so as to match the shape of the vibrating body 116 while changing the meshing position with the internal gear 122 in the circumferential direction. The first external tooth portion 120b rotates relative to the first internal gear 122-A by an amount corresponding to the difference in the number of teeth with the first internal gear 122-A every time the vibrator 116 makes one rotation. (Rotate). At this time, the rotation of the vibrating body 116 is reduced at a reduction ratio according to the difference in the number of teeth with the first internal gear 122-A, and the external gear 120 rotates.

The first outer tooth portion 120b rotates integrally with the second outer tooth portion 120c in the same phase. Since the second internal gear 122-B has the same number of teeth as the second external tooth part 120c, the relative meshing position with the second external tooth part 120c changes before and after the oscillator 116 makes one rotation. Without being present, the first external tooth portion 120b rotates in synchronization with the same rotation component. The rotation component of the first external tooth portion 120b is transmitted to the output side carrier 114-B via the second internal gear 122-B. As a result, the rotation of the input shaft 14 is decelerated and output from the output side carrier 114-B.

FIG. 11 is a diagram showing an outer peripheral surface of the vibrator 116 in a cross section orthogonal to the axial direction. Similarly to the outer peripheral surface of the eccentric body 16 of the first embodiment, the outer peripheral surface of the vibrating body 116 of the present embodiment is also provided with the first high hardness region 48 and the first low hardness region 50. In this figure, the unhatched portion of the outer peripheral surface of the vibrator 116 is the first high hardness region 48, and the hatched portion is the first low hardness region 50. In the present embodiment, the vibrating body 116 is provided with one first low hardness region 50. These relationships are the same as those of the first high hardness region 48 and the first low hardness region 50 of the first embodiment.

In the present embodiment, the non-load range Sa is set as the range in which the first low hardness region 50 should be provided. This non-load range Sa is within ±45 degrees from the third reference line Lb3 extending along the minor axis direction Pe of the vibrator 116 from the rotation center line Le in the range around the rotation center line Le of the vibrator 116. It is a range. The minor axis direction Pe here refers to the minor axis direction of an ellipse formed by the cross-sectional shape of the vibrator 116. When the position where the distance from the rotation center line Le of the vibrator 116 to the outer peripheral surface is the minimum is called the short axis position, the short axis direction Pe is also understood as the direction in which the straight line connecting the two short axis positions extends. The first low hardness region 50 is provided so as to be entirely within this non-load range Sa. The reason for this will be explained.

When the vibrating body 116 rotates in the positive direction (clockwise direction in the figure), the vibrating body 116 is located within a range Se of −45 degrees from the fourth reference line Lb4 extending along the major axis direction Pf from the rotation center line Le. The maximum load is added to the area, and almost no load is added to other areas. Further, when the vibrator 116 rotates in the opposite direction (counterclockwise direction in the drawing), the maximum load is applied to any part within the range Sf of +45 degrees from the fourth reference line Lb4 extending in the long axis direction Pf. Is added, and almost no load is applied to other areas. That is, almost no load is applied to the vibrating body 116 in the non-load range Sa of ±45 degrees from the third reference line Lb3 extending along the minor axis direction Pe from the rotation center line Le.

If the first low hardness region 50 is provided in the non-load range Sa, a large load is not applied to the first low hardness region 50, and the life of the vibrating body 116 is reduced due to the first low hardness region 50. Can be prevented. Therefore, even if the heat treatment in which the high hardness region and the low hardness region appear in the work of the rotating body (oscillating body 116) that is a component for the speed reducer, the influence of the shortened life due to the low hardness region can be eliminated. Therefore, according to the present embodiment, it is possible to preferably adopt the heat treatment in which the high hardness region and the low hardness region appear in the work of the speed reducer component.

Although not shown, the first low hardness region 50 has a strip shape extending in the axial direction of the vibrating body 116 and inclined with respect to the axial direction, as in the first embodiment. Although the width and the inclination angle of the band formed by the first low hardness region 50 are not shown, the contact line Ld between the rolling surface 134 of the vibrating body 116 and the rolling body 128 is the first as in the first embodiment. When passing over the low hardness region 50, the contact line Ld is set so as to pass over the first high hardness region 48 as well. Thereby, when the rolling element 128 contacts the first low hardness region 50 of the vibration generator 116, the rolling element 128 can also contact the first high hardness region 48.

The vibrating body 116, which is the workpiece to be heat-treated in this embodiment, is also heat-treated by laser hardening using laser light, as in the first embodiment. The vibrating body 116 simultaneously heat-treats a range including the first inner rolling surface 134-A and the second inner rolling surface 134-B. In this heat treatment step, laser light is applied to the axial range including the inner rolling surfaces 134-A and 134-B of the vibrating body 116. In the same step, by changing the irradiation position of the laser beam to the vibrator 116 along the circumferential direction of the vibrator 116, the outer peripheral surface of the vibrator 116 is quenched in one process over the entire circumference.

At this time, similarly to the first embodiment, by changing the irradiation position of the laser light to the vibration generator 116 along the circumferential direction, after quenching the outer peripheral surface of the vibration generator 116 over the entire circumference, the laser light is emitted. The laser light is irradiated again to a part of the irradiated area. As a result, the first low hardness region 50 serving as a soft zone is provided by tempering in the laser beam re-irradiation range.

The re-irradiation range of the laser beam on the outer peripheral surface of the vibrator 116 is set so as to be within the non-load range Sa of the vibrator 116 described above. That is, the re-irradiation range is within ±45 degrees from the third reference line Lb3 extending along the minor axis direction Pe of the oscillator 116 in the range around the rotation center line Le of the oscillator 116 from the rotation center line Le. It is set to fit within the range. As a result, the first low hardness region 50 is provided in the non-load range Sa of the vibrator 116, and the first high hardness region 48 is provided in the other range of the outer peripheral surface of the vibrator 116.

The example of the embodiment of the present invention has been described above in detail. The embodiments described above are merely specific examples for implementing the present invention. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes such as modification of components, addition, deletion, etc. are possible within a range not departing from the idea of the invention defined in the claims. It is possible. In the above-described embodiment, the contents such as the design change are described with the notations such as “of the embodiment” and “in the embodiment”, but the contents without such notation are designed. Change is not unacceptable. Further, the hatching attached to the cross section of the drawing does not limit the material to which the hatching is attached.

The example in which the first high hardness region 48 and the first low hardness region 50 of the rotating body (the eccentric body 16 and the vibrating body 116) are obtained by laser hardening has been described. The heat treatment is not limited to this, and may be any heat treatment in which a high hardness region and a low hardness region appear on the work, and may be obtained, for example, by induction hardening.

In the first embodiment, the external gear oscillating speed reducer in which the mesh gear is the internal gear 22 and the oscillating gear is the external gear 20 has been described. In addition to this, the meshing gear may be used in the external gear 20, and the oscillating gear may be used in the internal oscillating speed reducer in which the internal gear 22 is used.

Although the eccentric body 16 of the first embodiment is described as an example in which it is configured separately from the input shaft 14, it may be configured integrally with the input shaft 14.

Although the eccentric body 16 of the first embodiment has been described as an example that also serves as the inner ring of the eccentric body bearing 18, it does not have to serve as the inner ring. In this case, the inner ring of the eccentric body bearing 18 constitutes a part of the eccentric body 16, and the outer peripheral surface of the inner ring constitutes the outer peripheral surface of the eccentric body 16.

The internal teeth of the internal gear 22 of the first embodiment have been described by way of the example of the outer roller 40, but the present invention is not limited to this, and may be formed on the inner peripheral surface of the casing 12, for example.

Although the example in which the input shaft 14 is inserted into the hollow portion 56 of the eccentric body 16 of the first embodiment has been described, the input shaft 14 may not be inserted. In this case, the hollow portion 56 of the eccentric body 16 may function as an oil passage dedicated for flowing the lubricating oil, and the inner diameter thereof may be smaller than that in the example of the embodiment.

In the first embodiment, the center crank type eccentric rocking type reduction gear device in which the eccentric body 16 is arranged at the axial center position of the internal gear 22 has been described as an example, but the present invention is not limited to this. For example, it may be applied to a distribution type eccentric oscillating reduction device in which a plurality of eccentric bodies are arranged at positions offset from the axis of the internal gear 22.

In the second embodiment, the cylindrical flexible mesh type reduction gear having the plurality of internal gears 122 has been described as an example. The type of the flexible mesh type speed reducer is not particularly limited, and may be applied to a so-called cup type or top hat type flexible mesh type speed reducer having one internal gear, for example.

The vibrating body 116 of the second embodiment has been described as an example that also serves as the inner ring of the vibrating body bearing 118, but it does not have to serve as the inner ring. In this case, the inner ring of the vibrating body bearing 118 constitutes a part of the vibrating body 116, and the outer peripheral surface of the inner ring constitutes the outer peripheral surface of the vibrating body 116.

An example of rotating the rotating body around the axis of the rotating body with respect to the head 60 in order to change the irradiation position of the laser light on the rotating body (the eccentric body 16, the vibrating body 116) along the circumferential direction of the rotating body. Explained. The present invention is not limited to this, and the head 60 may be rotated with respect to the rotating body around the axis of the rotating body.

10... Reduction gear, 16-A... 1st eccentric body, 16-B... 2nd eccentric body, 20... External gear, 26... Rolling body, 46... Eccentric body connection part, 46a... 1st outer peripheral surface part, 46b... 2nd outer peripheral surface part, 48... 1st high hardness region, 50... 1st low hardness region, 52... 2nd high hardness region, 54... 2nd low hardness region, 56... Hollow part, 116... Exciter, 120... External gear, 128... rolling element.

Claims (9)

An oscillating gear, an eccentric body that is a rotating body that oscillates the oscillating gear, and a rolling element that is arranged between the oscillating gear and the eccentric body. An eccentric oscillating speed reducer that constitutes a rolling surface of the rolling element,
The outer peripheral surface of the eccentric body is provided with a first high hardness region and a first low hardness region having a surface hardness lower than that of the first high hardness region,
The first low-hardness region is a reduction gear device that is provided within a range of about 90 degrees from a reference line extending in an anti-maximum eccentric direction from the axis, within a range around the axis of the eccentric body. Inside the eccentric body, a hollow portion extending in the axial direction, and a lubricating oil passage extending in the radial direction from the hollow portion and opening to the outer peripheral surface of the eccentric body are provided,
The speed reducer according to claim 1, wherein the lubricating oil passage opens in the first low hardness region. The eccentric body includes a first eccentric body and a second eccentric body which are adjacent to each other in the axial direction,
An eccentric body connecting portion is provided between the first eccentric body and the second eccentric body,
A second high hardness region and a second low hardness region having a surface hardness lower than that of the second high hardness region are provided on the outer peripheral surface of the eccentric body connecting portion,
The second low hardness region includes a first region portion that is continuous with the first low hardness region of the first eccentric body and a second region portion that is continuous with the first low hardness region of the second eccentric body. The reduction gear transmission according to claim 1 or 2 including. The eccentric body connecting portion has a first outer peripheral surface portion axially continuous with the outer peripheral surface of the first eccentric body, and a second outer peripheral surface portion axially continuous with the outer peripheral surface of the second eccentric body,
The speed reducer according to claim 3, wherein the second low hardness region includes a third region portion provided at a boundary portion between the first outer peripheral surface portion and the second outer peripheral surface portion. A flexible external gear, a vibrator that is a rotating body that bends and deforms the external gear and has an elliptical cross section perpendicular to the axis, and is arranged between the external gear and the vibrator. A rolling mesh type speed reducer, comprising: a rolling element, wherein the outer peripheral surface of the vibrating body constitutes a rolling surface of the rolling element,
A first high hardness region and a first low hardness region having a surface hardness lower than that of the first high hardness region are provided on an outer peripheral surface of the vibrating body,
The first low hardness region is provided within a range of about ±45 degrees from a reference line extending along the minor axis direction of the vibrator from the rotation center line in the range around the rotation center line of the vibrator. Reducer used. The reduction gear according to any one of claims 1 to 5, wherein the first low-hardness region has a strip shape that extends in the axial direction of the rotating body and is inclined with respect to the axial direction. The width and the inclination angle of the band formed by the first low hardness region are such that when the contact line between the rolling element and the rolling surface passes over the first low hardness region, the contact line is the first high hardness region. The speed reducer according to claim 6, wherein the speed reducer is set so as to pass above. A heat treatment method for a rotating body which is an eccentric body of an eccentric oscillating reduction gear,
The eccentric body oscillates an oscillating gear, and an outer peripheral surface constitutes a rolling surface of a rolling element arranged between the eccentric body and the oscillating gear,
Including a heat treatment step of heat treating the outer peripheral surface of the eccentric body by irradiating a laser beam from the head,
In the heat treatment step, by changing the irradiation position of the laser light along the circumferential direction of the outer peripheral surface, after quenching the outer peripheral surface over the entire circumference, the laser light is partially irradiated. Again, re-irradiate the laser light,
The re-irradiation range of the laser beam on the outer peripheral surface is set so as to be within ±90 degrees from a reference line extending in the direction of the anti-maximum eccentric direction from the axis of the range around the axis of the eccentric body. Method of heat treatment of rotating body. A heat treatment method for a rotating body which is a vibrating body of a flexible mesh type speed reducer, comprising:
The vibrating body rotates an external gear having flexibility and has an elliptical cross section perpendicular to the axis, and the outer peripheral surface constitutes a rolling surface of a rolling element arranged between the external gear and the external gear. ,
Including a heat treatment step of heat treating the outer peripheral surface of the vibrator by irradiating a laser beam from the head,
In the heat treatment step, by changing the irradiation position of the laser light along the circumferential direction of the outer peripheral surface, after quenching the outer peripheral surface over the entire circumference, the laser light is partially irradiated. Again, re-irradiate the laser light,
The re-irradiation range of the laser beam on the outer peripheral surface is ±45 degrees from the reference line extending along the minor axis direction of the vibrator from the rotation center line in the range around the rotation center line of the vibrator. The heat treatment method for the rotating body set to fall within the range.

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