JP2016080064A - Traction power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve concentricity of an internal ring to a second rotor including planetary rollers with a simple structure.SOLUTION: A first rotor 3 comprises a first rotating shaft part 31 and a sun roller 33. A second rotor 4 comprises: plural planetary rollers 43 that are arranged in the circumference direction and have respective outer peripheral surfaces contacting with the outer peripheral surface of the sun gear 33 and the inner peripheral surface of an internal ring 5; a planetary carrier part 42 rotatably supporting the plural planetary rollers 43 around a planetary center axis; and a second rotating shaft part 41 connected to the planetary carrier part 42. Utilizing elastic deformation of the internal ring 5, the plural planetary rollers 43 are pressed toward the sun roller 33. A mounting inner peripheral surface of the internal ring 5 is fixed to the outer peripheral surfaces of ring fixation bearings 24, 25, each of which is either a bearing supporting the first rotor 3 or the second rotor 4 relative to a casing 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a traction power transmission device.

  2. Description of the Related Art Conventionally, there is a traction power transmission device that presses a plurality of planetary rollers against an outer peripheral surface of a sun roller while interposing lubricating oil as a reduction gear or a speed increaser. In the traction power transmission device, vibration and noise due to backlash are reduced as compared with a gear transmission mechanism that meshes a plurality of gears.

In the planetary roller type power transmission device disclosed in the microfilm of Japanese Utility Model Publication No. 56-50309 (Japanese Utility Model Publication No. 57-163044), the plurality of planetary rollers are arranged between the sun roller and the elastic cylinder. . The planetary roller is pressed against the sun roller by the elastic cylinder. One end of the elastic cylinder is fixed to the casing.
Microfilm of Japanese Utility Model No. 56-50309 (Japanese Utility Model Publication No. 57-163044)

  By the way, in the traction power transmission device, high assembly accuracy is required. In particular, if the member that presses the planetary roller against the sun roller deviates from the central axis, the applied pressure fluctuates, causing vibration and fluctuations in the rotational speed. In the apparatus disclosed in the microfilm disclosed in Japanese Utility Model Application No. 56-50309 (Japanese Utility Model Application Publication No. 57-163044), one end of the elastic cylinder is fixed to the casing. Therefore, in order to improve the coaxiality between the elastic cylinder and the assembly including the planetary roller, high-grade processing is required for the casing, and the manufacturing cost of the parts increases.

  An object of the present invention is to improve the coaxiality of a member that presses a planetary roller against a sun roller with respect to an assembly including the planetary roller in a traction power transmission device with a simple structure.

  An exemplary traction power transmission device according to the present invention includes a casing, a first rotating body, a first bearing that rotatably supports the first rotating body with respect to the casing about a central axis, and the first bearing. A second rotating body that transmits power by traction with the rotating body; a second bearing that rotatably supports the second rotating body with respect to the casing about the central axis; and the second rotating body. An annular internal ring disposed on the outer side in the radial direction of the first rotating body, the first rotating body includes a first rotating shaft portion centered on the center axis, and the first rotating shaft within the casing. The second rotating body is disposed in the circumferential direction on the radially outer side of the sun roller in the casing, and each outer peripheral surface is an outer peripheral surface of the sun roller and The inter A plurality of planetary rollers in contact with the inner peripheral surface of the ruling, a planet carrier part that supports the plurality of planetary rollers in the casing so as to be rotatable about a planetary central axis facing the direction along the central axis, and the center A plurality of planetary rollers that are pressed toward the sun roller using elastic deformation of the internal ring, and a second rotating shaft portion connected to the planet carrier portion. The inner peripheral surface of the internal ring is fixed to the outer peripheral surface of a ring fixed bearing that is one of the bearings that supports the first rotating body or the second rotating body with respect to the casing.

  According to the present invention, the coaxiality of the internal ring with respect to the second rotating body including the planetary roller can be improved with a simple structure.

FIG. 1 is a longitudinal sectional view of a traction power transmission device according to one embodiment. FIG. 2 is an enlarged longitudinal sectional view showing the planetary roller and the vicinity thereof. FIG. 3 is an enlarged longitudinal sectional view showing the vicinity of the boundary between the first casing and the second casing. FIG. 4 is a longitudinal sectional view showing another example of the planetary roller. FIG. 5 is a longitudinal sectional view showing another example of attachment of the internal ring.

  FIG. 1 is a longitudinal sectional view showing a configuration of a traction power transmission device 1 according to an exemplary embodiment of the present invention. In FIG. 1, the cross section by the surface containing the central axis J1 of the traction power transmission device 1 is shown. The traction power transmission device 1 is used as a speed reducer or a speed increaser in, for example, a precision machine or a 3D measurement device.

  The traction power transmission device 1 includes a casing 2, a first rotating body 3, a second rotating body 4, and an internal ring 5. The casing 2 has a substantially cylindrical shape centered on the central axis J1. The casing 2 includes a first casing 21 and a second casing 22. The first casing 21 has a substantially cylindrical shape centered on a central axis J1 that faces in the vertical direction in FIG. The second casing 22 has a substantially cylindrical shape centered on the central axis J1. In the following description, for convenience, the first casing 21 side is described as the upper side and the second casing 22 side is the lower side along the central axis J1, but the direction of the central axis J1 does not necessarily coincide with the direction of gravity. In the following description, the vertical direction, which is the direction in which the central axis J1 faces, is also referred to as “axial direction”.

  The first casing 21 is disposed on the upper side of the second casing 22. The lower portion of the first casing 21 and the upper portion of the second casing 22 include a flange portion that extends perpendicularly to the central axis J1. In the cross-sectional position of FIG. 1, both flange parts are not shown. The first casing 21 is connected to the second casing 22 by a plurality of bolts at both flange portions. The plurality of bolts are arranged at substantially equal angular intervals in the circumferential direction around the central axis J1. In the following description, the circumferential direction around the central axis J1 is simply referred to as “circumferential direction”.

  The first casing 21 includes a bearing holding portion 211, a lid portion 212, and a cylindrical portion 213. The bearing holding portion 211 is substantially cylindrical and protrudes upward. The lid portion 212 extends from the lower portion of the bearing holding portion 211 outward in the radial direction around the central axis J1. In the following description, the radial direction around the central axis J1 is simply referred to as “radial direction”. The cylindrical portion 213 extends downward from the outer edge portion of the lid portion 212. The second casing 22 includes a bearing holding part 221 and a cylindrical part 222. The bearing holding part 221 is a lower part of the second casing 22. The cylindrical portion 222 extends upward from the outer edge portion of the bearing holding portion 221. The inner space of the casing 2 is formed by contacting the upper end of the cylindrical portion 213 and the lower end of the cylindrical portion 222.

  The first rotating body 3 includes a first rotating shaft portion 31 and a sun roller 33. Each of the first rotating shaft portion 31 and the sun roller 33 has a substantially cylindrical shape or a substantially columnar shape with the central axis J1 positioned at the center. In other words, the 1st rotating shaft part 31 and the sun roller 33 are arrange | positioned coaxially. The first rotating shaft portion 31 protrudes upward from the inside of the first casing 21 toward the outside of the casing 2. The sun roller 33 is connected to the lower end portion of the first rotating shaft portion 31. The sun roller 33 is located inside the casing 2. In addition, the sun roller 33 may be indirectly connected to the 1st rotating shaft part 31 through another member.

  A first bearing 24 is provided between the outer peripheral surface of the first rotating shaft portion 31 and the bearing holding portion 211 of the first casing 21. The first bearing 24 is located on the radially outer side with respect to the first rotating shaft portion 31. The first rotating shaft portion 31 is supported by the first bearing 24 so as to be rotatable with respect to the first casing 21. Thereby, the 1st rotary body 3 is rotatably supported by the casing 2 centering on the central axis J1. The first bearing 24 is, for example, a ball bearing. Various bearing mechanisms other than ball bearings may be used as the first bearing 24.

  The second rotating body 4 includes a second rotating shaft portion 41, a planet carrier portion 42, and a plurality of planet rollers 43. The diameter of the second rotation shaft portion 41 is larger than the diameter of the first rotation shaft portion 31. The planet carrier part 42 includes a first carrier 421, a plurality of planet shaft parts 422, and a second carrier 423. The second rotating shaft portion 41 has a substantially cylindrical shape or a substantially columnar shape with the central axis J1 positioned at the center. The second rotating shaft portion 41 projects downward from the inside of the second casing 22 toward the outside of the casing 2. In other words, the second rotating shaft portion 41 protrudes from the casing 2 on the side opposite to the first rotating shaft portion 31 in the axial direction. The planet carrier part 42 is arranged in the casing 2.

  The first carrier 421 has a substantially disk shape with the central axis J1 positioned at the center. The first carrier 421 is located below the plurality of planetary rollers 43. The upper end of the second rotation shaft portion 41 is connected to the first carrier 421. The second carrier 423 is located above the plurality of planetary rollers 43. In other words, the first carrier 421 is located on one side of the plurality of planetary rollers 43 in the axial direction, and the second carrier 423 is located on the other side of the plurality of planetary rollers 43 in the axial direction. The second rotating shaft portion 41, the first carrier 421, and the second carrier 423 are arranged coaxially with the central axis J1 as the center.

  The first carrier 421 supports the plurality of planetary shaft portions 422 from below. The second carrier 423 supports the plurality of planetary shaft portions 422 from above. The plurality of planetary shaft portions 422 are arranged at equiangular intervals in the circumferential direction on the radially outer side of the sun roller 33. In the example shown in FIG. 1, three planetary shaft portions 422 are arranged at intervals of 120 ° in the circumferential direction. In FIG. 1, only one planetary shaft portion 422 is shown among the plurality of planetary shaft portions 422. The same applies to the planetary roller 43.

  Each of the plurality of planetary shaft portions 422 has a substantially cylindrical shape facing the direction along the central axis J1. In the present embodiment, the planetary shaft portion 422 is parallel to the central axis J1. The plurality of planetary shaft portions 422 have the same shape and the same size. The “direction along the central axis J1” means a direction approximately parallel to the axial direction to which the central axis J1 faces and does not have to be strictly parallel to the axial direction. That is, the central axis of each planetary shaft portion 422 may be parallel to the central axis J1, or may be inclined by a small angle with respect to the central axis J1.

  In the traction power transmission device 1, the first carrier 421 is provided with a plurality of holes penetrating in the vertical direction. By inserting the lower portion of the planetary shaft portion 422 into each hole, the plurality of planetary shaft portions 422 are connected to the first carrier 421. Each planetary shaft portion 422 is fixed to the first carrier 421 so as not to rotate. The portion of each planetary shaft portion 422 that protrudes upward from the first carrier 421 is located at approximately the same position as the sun roller 33 in the axial direction.

  The first carrier 421 is provided with a plurality of other holes penetrating in the vertical direction between the planetary shaft portions 422 in the circumferential direction. The connecting shaft portion 424 is fixed to these holes. The connecting shaft portion 424 protrudes upward from the first carrier 421. In the present embodiment, the number of connecting shaft portions 424 is three. The connecting shaft portion 424 is located between the planetary rollers 43 in the circumferential direction. The planetary shaft portion 422 and the connecting shaft portion 424 are located at 60 ° intervals in the circumferential direction.

  The second carrier 423 is provided with a plurality of holes recessed upward from the lower surface. These holes do not penetrate the second carrier 423. The upper part of the planetary shaft part 422 and the upper part of the connecting shaft part 424 are inserted into the hole. The first carrier 421 and the second carrier 423 are connected by the planetary shaft portion 422 and the connecting shaft portion 424. The planetary shaft portion 422 and the connecting shaft portion 424 function as a connection portion that connects the first carrier 421 and the second carrier 423 in the axial direction.

  Each of the plurality of planetary rollers 43 is supported in the casing 2 via a plurality of planetary shaft portions 422. The plurality of planetary rollers 43 are arranged in the circumferential direction on the radially outer side of the sun roller 33. In the example shown in FIG. 1, three planetary rollers 43 are supported via three planetary shaft portions 422. Each planetary roller 43 has a substantially cylindrical shape located around the planetary shaft portion 422. The plurality of planetary rollers 43 have the same shape and the same size. A planetary bearing 45 is provided between the inner peripheral surface of the planetary roller 43 and the outer peripheral surface of the planetary shaft portion 422. The planetary bearing 45 is, for example, a needle bearing. As the planetary bearing 45, various bearing mechanisms other than the needle bearing may be used. Each planetary roller 43 is rotatably supported by the planetary shaft portion 422 with the planetary carrier portion 42 around the central axis facing the direction along the central axis J1 via the planetary bearing 45. Hereinafter, the central axis of the planetary shaft portion 422 is referred to as “planet central axis”. Although the central axis of the planetary roller 43 does not coincide with the central axis of the planetary shaft portion 422 in a strict sense, it substantially coincides, so that the central axis of the planetary roller 43 is also referred to as a “planetary central axis”. The planetary shaft 43 422 is accurately determined by the planetary roller 43, the first carrier 421, and the second carrier 423.

  The outer peripheral surfaces of the plurality of planetary rollers 43 are in contact with the outer peripheral surface of the sun roller 33. Specifically, a minute gap exists between each planetary roller 43 and the sun roller 33, and lubricating oil filled in the casing 2 exists in the minute gap. The outer peripheral surface of each planetary roller 43 is indirectly in contact with the outer peripheral surface of the sun roller 33 through an oil film of lubricating oil.

  A second bearing 25 is provided between the outer peripheral surface of the second rotating shaft portion 41 and the bearing holding portion 221 of the second casing 22. The second bearing 25 is located on the radially outer side of the second rotating shaft portion 41. The second rotating shaft portion 41 is rotatably supported with respect to the second casing 22 via the second bearing 25. Thereby, the 2nd rotary body 4 is rotatably supported by the casing 2 centering on the central axis J1. The second bearing 25 is, for example, a ball bearing. Various bearing mechanisms other than the ball bearing may be used as the second bearing 25.

  An inner carrier bearing 26 is disposed between the inner peripheral surface of the second carrier 423 and the outer peripheral surface of the first rotating shaft portion 31. The second carrier 423 is supported by the inner carrier bearing 26 so as to be rotatable with respect to the first rotating body 3. In other words, the inner carrier bearing 26 supports the first rotating body 3 including the sun roller 33 relative to the second carrier 423 so as to be relatively rotatable about the central axis J1. An outer carrier bearing 27 is disposed between the outer peripheral surface of the second carrier 423 and the inner peripheral surface of the cylindrical portion 213 of the first casing 21. The second carrier 423 is supported by the outer carrier bearing 27 so as to be rotatable with respect to the first casing 21. The outer carrier bearing 27 is inserted into the first casing 21 with a clearance fit. This prevents unnecessary force from acting on the second carrier 423. Between the upper end surface of the outer ring of the outer carrier bearing 27 and the lower surface of the first casing 21 facing the outer ring, an O-ring 7 that is an annular elastic body is disposed.

  The outer carrier bearing 27 improves the rigidity of the second rotating body 4 against a radial load. The outer carrier bearing 27 and the inner carrier bearing 26 improve the rigidity of the first rotating body 3 against a load in the radial direction. Further, the inner carrier bearing 26 can easily improve the coaxiality between the first rotating body 3 and the second rotating body 4. The inner carrier bearing 26 and the outer carrier bearing 27 overlap in the radial direction.

  The second carrier 423 has a two-stage cylindrical shape. The second carrier 423 includes a main body portion 461, an upward projecting portion 462, a top plate portion 463, and an upper end cylindrical portion 464. The main body 461 has an annular shape centered on the central axis J <b> 1 and is sandwiched between the inner carrier bearing 26 and the outer carrier bearing 27. The upper protruding portion 462 protrudes upward from the inner peripheral portion of the main body portion 461 and has a substantially cylindrical shape. The top plate portion 463 is an annular substantially flat plate that extends radially inward from the upper end of the upper protruding portion 462. The upward protruding portion 462 protrudes upward from the inner peripheral edge of the top plate portion 463 and has a substantially cylindrical shape.

  The top plate portion 463 covers the upper part of the inner carrier bearing 26. The upper end cylindrical portion 464 is close to the outer peripheral surface of the first rotating shaft portion 31. The upper part of the planetary shaft part 422 is cut away so as to avoid interference with the inner carrier bearing 26. The notched portion is close to or in contact with the outer peripheral surface of the inner carrier bearing 26. In the casing 2, the lubricant oil exists in a space between the inner carrier bearing 26, the outer carrier bearing 27, the second carrier 423, and the second bearing 25.

  FIG. 2 is an enlarged cross-sectional view showing a part of the traction power transmission device 1. The internal ring 5 is a substantially cylindrical member with the central axis J1 positioned at the center. The internal ring is disposed on the radially outer side of the second rotating body 4. The internal ring 5 includes an attachment part 51, a thin part 52, and a pressing part 53. The attachment portion 51 is a lower portion of the internal ring 5. The attachment portion 51 has an annular shape centered on the central axis J1. As shown in FIG. 1, the lower surface of the attachment portion 51 is in contact with the upper surface of the bearing holding portion 221 that is the lower portion of the second casing 22. The upper surface of the attachment portion 51 faces the first carrier 421. As shown in FIG. 2, the outer peripheral portion of the attachment portion 51 extends outward and upward.

  The thin portion 52 extends upward from the outer edge portion of the attachment portion 51. The thin portion 52 has a substantially cylindrical shape centered on the central axis J1. The thin portion 52 is located approximately radially outward of the first carrier 421. The pressing portion 53 extends upward from the upper end of the thin portion 52. The pressing portion 53 is also substantially cylindrical with the central axis J1 as the center. The thickness of the thin portion 52 in the radial direction is smaller than the thickness of the pressing portion 53 in the radial direction. In order to reduce the size of the traction power transmission device 1 in the axial direction, the distance between the lower surface of the first carrier 421 and the upper end of the second bearing 25 is the inner surface of the thin portion 52 and the outer peripheral surface of the first carrier 421. Is less than the distance between.

  As shown in FIG. 1, the attachment portion 51 is provided with a pin hole 511 that is recessed upward from the lower surface. The bearing holding portion 221 of the second casing 22 is also provided with a pin hole 223 that is recessed downward from the upper surface. In the present embodiment, four pin holes 511 and 223 are provided at equal intervals in the circumferential direction. A pin 224 is inserted into the pin holes 223 and 511. Thereby, even if a large circumferential force acts on the internal ring 5, rotation of the internal ring 5 relative to the casing 2 is prevented. The second bearing 25 is loosely fitted in the bearing holding portion 221 of the second casing 22.

  The rotation of the internal ring 5 relative to the casing 2 may be realized by components other than the pin hole 223, the pin 224, and the like. For example, rotation of the internal ring 5 may be prevented by providing a recess in the casing 2 and providing a protrusion on the internal ring 5 so that the recess and the protrusion contact each other in the circumferential direction. Conversely, a protrusion may be provided on the casing 2 and a recess may be provided on the internal ring 5. The detent part which prevents the rotation of the internal ring 5 with respect to the casing 2 in the circumferential direction can be provided in various forms. Preferably, rotation of the internal ring 5 is prevented by the rotation preventing portion of the internal ring 5 contacting the casing 2 or a portion fixed to the casing 2 in the circumferential direction.

  As shown in FIG. 2, the inner peripheral surface of the pressing portion 53 is in contact with the outer peripheral surface of the planetary roller 43. Specifically, the lubricating oil filled in the casing 2 is present in a minute gap existing between each planetary roller 43 and the internal ring 5. The outer peripheral surface of each planetary roller 43 is indirectly in contact with the pressing portion 53 via an oil film of lubricating oil. At the circumferential position where the pressing portion 53 contacts the planetary roller 43, the pressing portion 53 is slightly distorted radially outward. The thin portion 52 is also elastically deformed so as to follow this. Using the restoring force of the thin portion 52 and the pressing portion 53, that is, using the elastic deformation of the internal ring 5, the pressing portion 53 presses the plurality of planetary rollers 43 toward the sun roller 33.

  In order to elastically deform the internal ring 5, the internal ring 5 and the casing 2 are separated in the radial direction on the radially outer side of the plurality of planetary rollers 43. The gap between the internal ring 5 and the casing 2 is very small. Preferably, the radial width of the gap is larger than the radial width of the thin portion 52, that is, the thickness of the thinnest portion of the internal ring 5. small.

  The thin portion 52 may be provided in various modes as long as it is between the first contact point 61 where the internal ring 5 is in contact with the planetary roller 43 and the inner peripheral surface 512 of the mounting portion 51. Hereinafter, the inner peripheral surface 512 is referred to as “attachment inner peripheral surface 512”. The thin portion 52 is thinner in the radial direction than the radial thickness of the pressing portion 53 at the first contact point 61. In addition, the thin part 52 may be provided so that the outer peripheral surface of the internal ring 5 may be depressed. The thin portion 52 may be provided so that the inner peripheral surface and the outer peripheral surface of the internal ring 5 are recessed.

  By providing the thin portion 52, the elastic deformation of the internal ring 5 can be concentrated on the thin portion 52. Thereby, the inclination with respect to the central axis J1 of the press part 53 is suppressed. As a result, the first contact point 61 between the pressing portion 53 and the planetary roller 43 can be easily positioned at a desired position in the axial direction. Further, since the movement of the contact position in the axial direction is reduced when the internal ring 5 is elastically deformed, the length of the planetary roller 43 in the axial direction can be shortened.

  In the traction power transmission device 1, the mounting inner peripheral surface 512 is fixed to the outer peripheral surface 251 of the second bearing 25. The second bearing 25 is a ring fixed bearing to which the internal ring 5 is fixed. Preferably, the attachment portion 51 is fixed to the outer peripheral surface of the second bearing 25 by press fitting or shrink fitting. In these methods, the internal ring 5 can be easily fixed to the second bearing 25 without an additional member. Thereby, the coaxiality of the internal ring 5 with respect to the 2nd rotary body 4 containing the planetary roller 43 can be improved with a simple structure.

  If the internal ring 5 is attached to the casing 2 and the position and orientation of the central axis of the internal ring 5 are determined by the mounting surface of the casing 2, the mounting surface of the casing 2 and the inner peripheral surface of the bearing holding portion 221. A high degree of coaxiality is required between As a result, the manufacturing cost of the casing 2 increases. Further, when the coaxiality between the internal ring 5 and the second rotating body 4 is low, it is difficult to rotate the second rotating body 4 at a constant speed. On the other hand, in the traction power transmission device 1, the position and orientation of the central axis of the internal ring 5 are determined using the outer peripheral surface 251 of the second bearing 25, thereby reducing the manufacturing cost of the traction power transmission device 1. can do.

  The diameter of the inner periphery of the internal ring 5 at the first contact point 61 where the planetary rollers 43 and the internal ring 5 are in contact with each other is larger than the diameter of the outer peripheral surface of the second bearing 25. Thereby, size reduction of the outer diameter of the lower part of the traction power transmission device 1 becomes easy.

  In FIG. 2, the first contact point 61 between each planetary roller 43 and the internal ring 5 and the second contact point 62 between each planetary roller 43 and the sun roller 33 are indicated by solid circles. The first contact point 61 and the second contact point 62 actually have a certain size. Further, the first pressing force vector V1 indicating the first pressing force acting on each planetary roller 43 from the internal ring 5 at the first contact point 61 and the sun roller 33 acting on each planetary roller 43 at the second contact point 62. A second pressing force vector V2 indicating the second pressing force is indicated by an arrow.

  The first contact point 61 and the second contact point 62 of each planetary roller 43 are located at different positions in the axial direction. Note that when the planetary shaft portion 422 is inclined with respect to the central axis J1, in the following description of the force, the axial direction accurately corresponds to a direction parallel to the planetary central axis J2 of the planetary shaft portion 422. However, since the inclination of the planetary shaft part 422 is slight, these do not need to be strictly distinguished. In the example shown in FIG. 1, the second contact point 62 is closer to the first carrier 421 than the first contact point 61 in the axial direction. The second contact point 62 substantially coincides with the center of the planetary roller 43 in the axial direction. The first contact point 61 is located between the center of the planetary roller 43 in the axial direction and the upper end of the planetary roller 43 with respect to the axial direction.

  At the first contact point 61 and the second contact point 62, the cross-sectional shape of the outer peripheral surface of each planetary roller 43 by the surface including the central axis J1 is convex. In other words, in each planetary roller 43, the cross-sectional shape at the first contact point 61 of the outer peripheral surface of each planetary roller 43 by the surface including the first contact point 61 and the central axis J1 is centered on the planetary central axis J2. It is convex outward in the radial direction. The cross-sectional shape at the second contact point 62 of the outer peripheral surface by the surface including the second contact point 62 and the central axis J1 is convex outward in the radial direction centered on the planetary central axis J2. Actually, since the longitudinal section of the outer peripheral surface is slightly convex in an arc shape at the first contact point 61 and the second contact point 62, the convex shape is not shown in FIG.

  The outer diameter of the planetary roller 43 is maximum at the approximate center in the axial direction of the planetary roller 43. The outer diameter of the planetary roller 43 is the distance between the outer peripheral surface of each planetary roller 43 and the planetary central axis J2 in the radial direction centered on the planetary central axis J2. The outer diameter of the planetary roller 43 gradually decreases with increasing distance from the substantial center of the planetary roller 43 in the planetary axis direction.

  In the internal ring 5, the diameter of the inner peripheral surface of the pressing portion 53 gradually decreases upward. Since the amount of decrease is small, it is not shown in FIG. By making the inner peripheral surface of the pressing portion 53 an inclined surface, the axial position of the first contact point 61 and the axial position of the second contact point 62 can be easily made different. Furthermore, the axial distance between the first contact point 61 and the second contact point 62 can be changed only by changing the inclination angle of the inner peripheral surface of the pressing portion 53 in terms of design. Further, the direction of the force acting on the planetary roller 43 from the internal ring 5 at the first contact point 61 can also be changed. That is, the magnitude of the force for inclining the planetary roller 43 can be easily changed in design. Thereby, the balance between torque transmission efficiency and backlash can be easily adjusted.

  The diameter of the inner peripheral surface of the pressing portion 53 does not need to be gradually changed over the entire axial length of the pressing portion 53. Moreover, the diameter of the inner peripheral surface of the pressing portion 53 may gradually decrease upward. Generally speaking, at the first contact point 61, the diameter of the inner peripheral surface of the internal ring 5 gradually decreases or increases toward one side in the axial direction. It is also possible to design such that the axial positions of the first contact point 61 and the second contact point 62 are substantially matched in a state where the inner ring 5 is not inclined and the internal ring 5 is elastically deformed.

  When the traction power transmission device 1 is used as a speed reducer, the sun roller 33 rotates around the central axis J1 together with the first rotary shaft portion 31 that is a high-speed shaft. In other words, the first rotating body 3 rotates around the central axis J1. Due to the rotation of the sun roller 33, traction is generated in the lubricating oil existing in the minute gap between the sun roller 33 and each planetary roller 43. Due to the traction, each planetary roller 43 rotates around the planetary central axis J2. Due to the rotation of each planetary roller 43, traction is generated in the lubricating oil present in the minute gap between each planetary roller 43 and the internal ring 5. Since the internal ring 5 is indirectly fixed to the casing 2, the plurality of planetary rollers 43 rotate around the central axis J <b> 1 by the traction.

  In the following description, the rotation of each planetary roller 43 around the planetary central axis J2 is called “spinning”, and the rotation of the plurality of planetary rollers 43 around the central axis J1 is called “revolution”. As described above, the first carrier 421 and the second carrier 423 are connected to the plurality of planetary rollers 43 via the plurality of planetary shaft portions 422, and the second rotating shaft portion 41, which is a low-speed shaft, is connected to the first carrier 421. Connected. For this reason, with the revolution of the plurality of planetary rollers 43, the first carrier 421, the second carrier 423, and the second rotating shaft portion 41 also rotate around the central axis J1. That is, the second rotating body 4 rotates about the central axis J1.

  When the traction power transmission device 1 is used as a speed increaser, the second rotation shaft portion 41 of the second rotating body 4, the first carrier 421, and a plurality of planetary rollers, contrary to the case where it is used as a speed reducer. 43 and the second carrier 423 rotate around the central axis J1. Each planetary roller 43 rotates by traction generated between the planetary roller 43 and the internal ring 5 during revolution. Due to the rotation of each planetary roller 43, traction is generated between each planetary roller 43 and the sun roller 33. And by the said traction, the sun roller 33 and the 1st rotating shaft part 31 of the 1st rotary body 3 rotate centering on the central axis J1.

  Thus, even when the traction power transmission device 1 is used as a speed reducer or a speed increaser, power transmission by traction is transmitted between the first rotating body 3 and the second rotating body 4. Done.

  As shown in FIG. 2, the first contact point 61 and the second contact point 62 of each planetary roller 43 are located at different positions with respect to the axial direction. Thereby, the central axis of each planetary roller 43 is slightly inclined with respect to the central axis of the planetary shaft portion 422 in a strict sense. As a result, the upper end portion of the inner peripheral surface of the planetary roller 43 is pressed through the planetary bearing 45 to a portion of the outer peripheral surface of the planetary shaft portion 422 in the radial direction centered on the central axis J1. Further, the lower end portion of the inner peripheral surface of the planetary roller 43 is pressed through a planetary bearing 45 to a radially inner portion centering on the central axis J <b> 1 in the outer peripheral surface of the planetary shaft portion 422.

  The vertical relationship between the first contact point 61 and the second contact point 62 may be reversed. Generally speaking, one of the upper end portion and the lower end portion of the inner peripheral surface of the planetary roller 43 is arranged on a portion of the outer peripheral surface of the planetary shaft portion 422 on the outer side in the radial direction centered on the central axis J1. It is pressed through the bearing 45. Further, the other of the upper end portion and the lower end portion of the inner peripheral surface of the planetary roller 43 is disposed on the radially inner side centered on the central axis J1 on the outer peripheral surface of the planetary shaft portion 422 via the planetary bearing 45. Pressed. As a result, in the traction power transmission device 1, the planetary roller 43 is inclined with respect to the planetary shaft portion 422, and backlash between the planetary shaft portion 422 and the rotating planetary roller 43 can be reduced.

  As shown in FIG. 2, in the cross section of each planetary roller 43 by a plane including the planetary central axis J2, the first contact point 61, and the second contact point 62, the first pressing force vector V1 is It inclines to one side with respect to a virtual straight line L1 connecting the second contact point 62. The second pressing force vector V2 is inclined to the other side with respect to the straight line L1. In the example shown in FIG. 2, the first pressing force vector V1 is inclined upward with respect to the straight line L1, and the second pressing force vector V2 is inclined downward with respect to the straight line L1. The first pressing force vector V1 and the second pressing force vector V2 are substantially parallel.

  Thus, in each planetary roller 43, the first pressing force vector V1 and the second pressing force vector V2 are inclined in opposite directions with respect to the straight line L1. As a result, the component of the first pressing force vector V1 in the direction perpendicular to the planetary central axis J2 and the component of the second pressing force vector V2 in the direction perpendicular to the planetary central axis J2 can be increased.

  As described above, at the first contact point 61 of each planetary roller 43, the cross-sectional shape of the outer peripheral surface of each planetary roller 43 by the surface including the central axis J1 is convex. At the first contact point 61, the cross-sectional shape of the outer peripheral surface of the planetary roller 43 is not necessarily convex, and the cross-sectional shape of the inner peripheral surface of the pressing portion 53 of the internal ring 5 by the surface including the central axis J1 is convex. There may be. In other words, at the first contact point 61 of each planetary roller 43, the cross-sectional shape of the outer peripheral surface of each planetary roller 43 by the surface including the central axis J1 and the inner peripheral surface of the pressing portion 53 by the surface including the central axis J1. Of these cross-sectional shapes, at least one of the cross-sectional shapes is convex. Accordingly, the position of the first contact point 61 can be smoothly changed when the planetary roller 43 slightly moves in the planetary axis direction.

  Further, in the traction power transmission device 1, the cross-sectional shape of the outer peripheral surface of each planetary roller 43 by the surface including the central axis J1 is convex at the second contact point 62 of each planetary roller 43. At the second contact point 62, the cross-sectional shape of the outer peripheral surface of the planetary roller 43 is not necessarily convex, and the cross-sectional shape of the outer peripheral surface of the sun roller 33 by the surface including the central axis J1 may be convex. In other words, at the second contact point 62 of each planetary roller 43, the cross-sectional shape of the outer peripheral surface of each planetary roller 43 by the surface including the central axis J1 and the outer peripheral surface of the sun roller 33 by the surface including the central axis J1. Of the cross-sectional shapes, at least one of the cross-sectional shapes is convex. Thereby, the position of the second contact point 62 can be smoothly changed when the planetary roller 43 slightly moves in the planetary axis direction.

  FIG. 3 is an enlarged longitudinal sectional view showing the vicinity of the boundary between the first casing 21 and the second casing 22. The first casing 21 is a part of the casing 2 on the first rotating body 3 side, and the second casing 22 is a part of the casing 2 on the second rotating body 4 side. The first casing 21 and the second casing 22 are in contact with each other in the axial direction. The upper end of the internal ring 5 is located below the upper end of the second casing 22. Therefore, the upper end of the internal ring 5 is located in the second casing 22. The upper end of the internal ring 5 is the end of the internal ring 5 on the opposite side to the mounting inner peripheral surface 512 shown in FIG.

  In the final process of assembling the traction power transmission device 1, the first casing 21 and the second casing 22 are fastened. At this time, since the upper end of the internal ring 5 is located in the second casing 22, it is reliably avoided that the first casing 21 and the internal ring 5 come into contact with each other. In the fastening operation between the first casing 21 and the second casing 22, the operator finally adjusts so that the central axis of the first rotating body 3 and the central axis of the second rotating body 4 accurately coincide with each other. Is called. At this time, the radial gap of the second bearing 25 that supports the second rotating body 4 is reduced by the pressurizing effect that the O-ring 7 shown in FIG. 1 pushes the outer ring of the outer carrier bearing 27 downward. Thereby, the freedom degree of the axial center of the 2nd rotary body 4 is lose | eliminated. As a result, the central axis of the first casing 21 and the central axis of the second casing 22 are aligned, and the central axis of the first rotating body 3 and the central axis of the second rotating body 4 can be easily matched. it can.

  In the traction power transmission device 1, it is preferable to reduce the axial gap between the internal ring 5 and the outer carrier bearing 27 as much as possible in order to reduce the size in the axial direction. Therefore, the boundary between the first casing 21 and the second casing 22 overlaps with the outer carrier bearing 27 in the radial direction. On the other hand, a clearance for adjusting the relative position in the radial direction is required between the first casing 21 and the second casing 22. Therefore, the inner diameter of the upper end of the second casing 22 is the diameter of the outer peripheral surface of the outer carrier bearing 27 so that a gap exists between the outer peripheral surface of the outer carrier bearing 27 and the inner peripheral surface of the second casing 22. Slightly larger than.

  FIG. 4 is a longitudinal sectional view showing another example of the planetary roller 43, and shows only the same parts as in FIG. The planetary roller 43 has an upper diameter smaller than a lower diameter. The upper portion of the planetary roller 43 is in contact with the pressing portion 53 of the internal ring 5, and the lower portion is in contact with the sun roller 33. In the planetary roller 43, the upper diameter may be larger than the lower diameter. Moreover, it can be arbitrarily designed whether the pressing part 53 and the sun roller 33 are in contact with the upper part or the lower part of the planetary roller 43.

  The other structure of the traction power transmission device 1 of FIG. 4 is the same as that of FIG. The diameter of the inner peripheral surface of the pressing portion 53 gradually increases or decreases toward one side in the axial direction. Furthermore, the relationship between the first pressing force vector and the second pressing force vector at the first contact point and the second contact point is the same as in FIG.

  FIG. 5 is a longitudinal sectional view showing another example of attachment of the internal ring 5. In the internal ring 5 of FIG. 5, the attachment portion 51, the thin portion 52, and the pressing portion 53 are arranged from the top in the reverse order of FIG. 1. The mounting inner peripheral surface 512 of the mounting portion 51 is fixed to the outer peripheral surface of the first bearing 24. Further, the second carrier 423, the inner carrier bearing 26 and the outer carrier bearing 27 of FIG. 1 are omitted. The other structure is the same as that of the traction power transmission device 1 of FIG.

  In the traction power transmission device 1 of FIG. 5, high coaxiality between the first rotating body 3 and the internal ring 5 can be easily obtained by using the outer peripheral surface of the first bearing 24. Since the center axis of the first rotator 3 and the center axis of the second rotator 4 exactly coincide with each other due to the adjustment at the time of assembly, it is high between the second rotator 4 and the internal ring 5 after assembly. Coaxiality is obtained.

  As shown in FIG. 5, the ring fixed bearing including the outer peripheral surface to which the mounting inner peripheral surface 512 of the internal ring 5 is fixed may be the first bearing 24. Furthermore, the outer carrier bearing 27 of FIG. 1 may be used as a ring fixed bearing. Generally speaking, the outer peripheral surface of a ring fixed bearing in which the inner peripheral surface 512 of the internal ring 5 is one of the bearings that supports the first rotating body 3 or the second rotating body 4 with respect to the casing 2. As a result, the high degree of coaxiality between the second rotating body 4 and the internal ring 5 can be easily obtained.

  Also in the example shown in FIG. 5, the internal ring 5 is fixed to the first bearing 24 by press fitting or shrink fitting. It is preferable that a rotation stopper is provided between the internal ring 5 and the first casing 21. The diameter of the inner peripheral surface of the pressing portion 53 gradually increases or decreases toward one side in the axial direction. Furthermore, the relationship between the first pressing force vector and the second pressing force vector at the first contact point and the second contact point is the same as in FIG. The diameter of the inner circumference of the internal ring 5 at the first contact point is larger than the diameter of the inner circumference surface of the attachment portion 51.

  In the traction power transmission device 1, various changes are possible.

  The casing 2 may be composed of three or more parts. The number of the first bearings 24 and the second bearings 25 may be changed as appropriate. Another bearing that supports the first rotating body 3 or the second rotating body 4 may be provided.

  The internal ring 5 may be annular and is not limited to a cylindrical shape. If the internal ring 5 is elastically deformed, the thin portion 52 may not be provided in the internal ring 5. The mounting portion 51 of the internal ring 5 need not be fixed to the entire circumference of the outer peripheral surface of the ring fixed bearing. For example, a groove extending in the axial direction may be provided in the inner peripheral portion of the attachment portion 51 and may partially contact the ring fixed bearing. An adhesive may be used for fixing the internal ring 5 and the ring fixed bearing. For example, the internal ring 5 may be fixed to the ring fixed bearing by press-fitting and an adhesive.

  In the planet carrier part 42, the connection part for connecting the first carrier 421 and the second carrier 423 in the axial direction may be only the planetary shaft part 422 or only the connecting shaft part 424. The number of planetary rollers is not limited to three. In the planet carrier part 42, the first carrier 421 or the second carrier 423 may be omitted. When the first carrier 421 is omitted, for example, the second rotation shaft portion 41 is connected to the second carrier 423.

  In the traction power transmission device described above, the first rotating shaft portion 31 and the second rotating shaft portion 41 may be disposed in the casing 2. The first rotating shaft portion 31 and the second rotating shaft portion 41 do not necessarily protrude from the casing 2 in opposite directions. For example, one of the first rotating shaft portion 31 and the second rotating shaft portion 41 is not required. A member may be hollow and the other member may be located in the radial inside of the one member.

  In the second rotating body 4, the planetary roller 43 may be fixed to the planetary shaft portion 422, and the planetary bearing 45 may be provided between the planetary shaft portion 422 and the first carrier 421 or the second carrier 423. In other words, the planetary roller 43 is rotatably supported by the planetary carrier part 42 via the planetary shaft part 422 and the planetary bearing 45. The planetary roller 43 rotates with the planetary shaft portion 422.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

  The traction power transmission device according to the present invention can be used as a speed reducer or speed increaser in various devices such as precision processing machines and 3D measuring devices. The traction power transmission device according to the present invention can also be used for other purposes.

DESCRIPTION OF SYMBOLS 1 Traction power transmission device 2 Casing 3 1st rotary body 4 2nd rotary body 5 Internal ring 21 1st casing 22 2nd casing 24 1st bearing (ring fixed bearing)
25 Second bearing (ring fixed bearing)
26 Inner carrier bearing 27 Outer carrier bearing 31 First rotating shaft portion 33 Sun roller 41 Second rotating shaft portion 42 Planet carrier portion 43 Planet roller 52 Thin portion 61 First contact point 62 Second contact point 223 Pin hole (rotating portion) )
421 First carrier 422 Planetary shaft part (connection part)
423 Second carrier 424 Connection shaft portion (connection portion)
512 mounting inner peripheral surface J1 central axis J2 planet central axis L1 straight line V1 first pressing force vector V2 second pressing force vector

Claims (12)

A casing,
A first rotating body;
A first bearing that rotatably supports the first rotating body with respect to the casing about a central axis;
A second rotating body that transmits power by traction with the first rotating body;
A second bearing that rotatably supports the second rotating body with respect to the casing about the central axis;
An annular internal ring disposed on the radially outer side of the second rotating body;
With
The first rotating body includes:
A first rotating shaft portion having the center axis positioned at the center;
A sun roller that rotates with the first rotating shaft in the casing;
With
The second rotating body is
A plurality of planetary rollers disposed in a circumferential direction on the radially outer side of the sun roller in the casing, each outer peripheral surface being in contact with the outer peripheral surface of the sun roller and the inner peripheral surface of the internal ring,
A planet carrier portion that supports the plurality of planetary rollers in the casing so as to be rotatable about the planetary central axis facing the direction along the central axis;
A second rotating shaft portion that is located at the center and connected to the planet carrier portion;
With
Using the elastic deformation of the internal ring, the plurality of planetary rollers are pressed toward the sun roller,
A traction power transmission in which an inner peripheral surface of the internal ring is fixed to an outer peripheral surface of a ring fixed bearing that is one of the bearings that supports the first rotating body or the second rotating body with respect to the casing. apparatus.   The traction power transmission device according to claim 1, wherein the internal ring is fixed to the outer peripheral surface of the ring fixed bearing by press fitting or shrink fitting.   The traction power transmission device according to claim 1, wherein the internal ring includes a rotation preventing portion that prevents circumferential rotation with respect to the casing.   The internal ring includes a thin portion between a contact point in contact with the plurality of planetary rollers and the inner peripheral surface of the attachment, with a thin portion having a radial thickness smaller than a radial thickness at the contact point. Item 4. The traction power transmission device according to any one of Items 1 to 3. At a first contact point between each planetary roller of the plurality of planetary rollers and the internal ring, the diameter of the inner peripheral surface of the internal ring gradually decreases or increases toward one side in the axial direction,
The traction power transmission device according to any one of claims 1 to 4, wherein the first contact point and the second contact point between each planetary roller and the sun roller are located at different positions in the axial direction. The first contact point between each planetary roller of the plurality of planetary rollers and the internal ring and the second contact point between each planetary roller and the sun roller are located at different positions in the axial direction,
For each planetary roller, a first pressing force that acts on each planetary roller from the internal ring in a cross section by a plane including the planetary central axis of the planetary roller, the first contact point, and the second contact point. The first pressing force vector shown is inclined to one side with respect to a straight line connecting the first contact point and the second contact point, and indicates a second pressing force acting on each planetary roller from the sun roller. The traction power transmission device according to claim 1, wherein the two pressing force vectors are inclined to the other side with respect to the straight line. The casing is
A first casing on the first rotating body side;
A second casing on the second rotating body side that is in axial contact with the first casing;
With
The second bearing is the ring fixed bearing,
The traction power transmission device according to any one of claims 1 to 6, wherein an end of the internal ring opposite to the mounting inner peripheral surface in the axial direction is located in the second casing. The planet carrier part is
A first carrier located on one axial side of the plurality of planetary rollers and connected to the second rotating shaft;
A second carrier located on the other axial side of the plurality of planetary rollers;
A connecting portion for connecting the first carrier and the second carrier in the axial direction;
With
The traction power according to any one of claims 1 to 7, further comprising an outer carrier bearing that rotatably supports the second carrier about the central axis between the second carrier and the casing. Transmission device. The second bearing is the ring fixed bearing,
The traction power transmission device according to claim 8, wherein the internal ring and the casing are radially separated from each other on a radially outer side of the plurality of planetary rollers. The casing is
A first casing on the first rotating body side;
A second casing on the second rotating body side that is in axial contact with the first casing;
With
The boundary between the first casing and the second casing overlaps the outer carrier bearing in the radial direction,
The traction power transmission device according to claim 9, wherein a gap exists between an outer peripheral surface of the outer carrier bearing and an inner peripheral surface of the second casing.   11. The traction power transmission device according to claim 8, further comprising an inner carrier bearing that rotatably supports the sun roller relative to the second carrier about the central axis.   The diameter of the inner periphery of the internal ring at a contact point where the plurality of planetary rollers and the internal ring are in contact is larger than the diameter of the outer peripheral surface of the ring fixed bearing. The traction power transmission device described in 1.

Images