JP2009243677A - Planetary roller type rotation transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To substantially eliminate gaps related to a bearing member of a planetary roller, and to suppress rotation unevenness by improving rigidity of the planetary roller. <P>SOLUTION: The planetary roller 41 has a pair of shaft parts 41b, 41b for carrying out two edge support of a cylinder rolling part 41a via a bearing member 31. The bearing member 31 is a tapered roller bearing or an angular bearing, and it has an inner side bearing ring 31a fitted on the shaft part 41b, an outer side bearing ring 31b mounted to a planetary frame 61, and rolling elements 31c rolling between the bearing rings 31a, 31b. A pushing member 67 for pushing the outer side bearing ring 31b toward the inner side bearing ring 31a is screwed to the planetary frame 61 by holding a pair of the bearing members 31, 31 in a direction along a rotary shaft C41 by predetermined portions 63a of the planetary frame 61 while mounting the bearing members 31, 31 in correspondence to the pair of shaft parts 41b, 41b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a planetary roller type rotation transmission device that shifts and outputs input rotation.

  In recent years, there are increasing cases of using servo motors, which have been able to obtain highly accurate rotational output due to advances in servo technology, as drive sources for various devices. In use, a transmission is generally interposed between the servo motor and the device for the purpose of adapting to the required rotational speed (rpm) and required torque of the device to be applied. For this reason, in order to finally supply high-accuracy rotation to the device, the transmission also requires high-accuracy rotation, that is, a transmission with small rotation unevenness (rotational speed fluctuation) is awaited. Has been.

  On the other hand, a planetary roller type rotation transmission device 101 as shown in Patent Document 1 is conventionally known as one of transmissions. FIG. 1 shows a cross-sectional view of the device 101. The device 101 rolls while being pressed against the outer surface of the solar shaft body 121 and the solar shaft body 121 with a predetermined pressure contact force. A plurality of planetary rollers 141 revolving around the planetary frame 141, and a planetary frame 161 capable of rotating based on the revolving operation of the planetary roller 141 while holding the planetary roller 141 rotatably through the bearing member 131. Configured. Then, when rotation is input to the solar shaft 121, the planetary roller 141 pressed against the outer peripheral surface of the solar shaft 121 revolves while rolling on the outer peripheral surface of the solar shaft 121, and based on this revolving operation. Since the planetary frame 161 also rotates, the decelerated rotation is output using the planetary frame 161 as an output shaft.

  Here, Patent Document 1 shows an example in which a cylindrical body 143 is used as a main body of the planetary roller 141 and a ball bearing as a bearing member 131 is built in together with a support shaft 145 on the inner peripheral side thereof.

Similarly, Patent Document 2 (not shown) similarly shows an example in which a cylindrical body is used as the main body of the planetary roller, and a needle bearing as a bearing member is built in together with a support shaft on the inner peripheral side thereof.
Shokai 57-163044 JP-A-5-157149

  However, when a ball bearing or a needle bearing is used as the bearing member 131 of the planetary roller 141 in this way, there is a risk of causing uneven rotation due to a gap between components of the bearing member 131. That is, the bearing member 131 generally includes (1) an inner race ring 133 provided on the support shaft 145 side, (2) an outer race ring 135 provided on the planetary roller side, and (3) these orbits. A rolling body 137 such as a sphere or a needle that rolls between the wheels, but between the races 133 and 135 and the rolling body 137, a direction along the support shaft 145 and a radial direction are provided. Although it is small, there is a gap, and the gap may induce uneven rotation. Therefore, in order to eliminate the rotation unevenness, it is necessary to eliminate such a small gap almost completely.

  In order to suppress the rotation unevenness, it is effective to increase the rigidity of the planetary roller 141 itself. However, in the configuration in which the bearing member 131 and the support shaft 145 are incorporated in the planetary roller 141 as in Patent Documents 1 and 2, As described above, the hollow cylindrical body 143 must be used as the main body of the planetary roller 141, and as a result, the planetary roller 141 itself may have low rigidity.

  Furthermore, in the planetary roller 141 of Patent Document 1, the support method of the planetary roller 141 is cantilevered, and therefore the support shaft 145 of the planetary roller 141 is unidirectionally caused by the pressure contact force acting on the planetary roller 141. And the planetary roller 141 comes into contact with the sun shaft 121. That is, contact between the planetary roller 141 and the sun shaft 121 is not uniform over the entire surface of the planetary roller 141. Then, the planetary roller 141 moves in the direction along the support shaft 145, and when the moved planetary roller 141 suddenly returns to its original position due to some cause, the movement induces uneven rotation. End up.

  The present invention has been made in view of such conventional problems, and is a planetary roller type rotation transmission device that can substantially eliminate a gap related to a bearing member of a planetary roller, improve the rigidity of the planetary roller, and suppress rotation unevenness. The purpose is to provide.

The main invention for achieving this object is:
A planetary roller type rotation transmission device that shifts and outputs input rotation,
A solar shaft body housed in a housing and rotatable about an axis;
A plurality of planetary rollers that revolve around the solar shaft while rotating by rolling while being pressed against the outer peripheral surface of the solar shaft by a predetermined pressure contact force,
A planetary frame supported by the housing so as to be able to rotate based on a revolving operation of the planetary roller while holding the planetary roller so as to be capable of rotating about a rotation axis via a bearing member;
The planetary roller is provided so as to cover the planetary roller from the outside while being supported by the housing, and the planetary roller rolls on the inner peripheral surface while applying the pressing force to the planetary roller by pressing the planetary roller against the solar shaft body. An elastic ring body,
The planetary roller integrally protrudes in a direction along the rotation axis from a cylindrical rolling part that rolls on the outer peripheral surface of the solar shaft body and the inner peripheral surface of the elastic ring body, and from both end faces of the cylindrical rolling part. And a pair of shaft portions for supporting both ends of the cylindrical rolling portion via the bearing member,
The bearing member is a tapered roller bearing or an angular bearing,
The bearing member includes an inner race that is fitted to the shaft portion of the planetary roller, an outer race that is disposed to face the outer peripheral surface of the inner race, and a space between the races. A plurality of rolling elements that roll in the annular space of
The rolling element is regulated to move inward in the radial direction and in one direction along the rotation axis by the inner raceway, and to move outward in the radial direction by the outer raceway. And movement in the direction opposite to the one direction along the rotation axis is restricted,
In a state where the bearing members are attached to correspond to the pair of shaft portions, the pair of the bearing members are sandwiched in a direction along the rotation axis by a predetermined portion of the planetary frame, and the outer race ring is The planetary roller type rotation transmission device is characterized in that a pushing member for pushing toward the inner raceway is screwed to the planetary frame.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  ADVANTAGE OF THE INVENTION According to this invention, while eliminating the clearance gap concerning the bearing member of a planetary roller substantially, the rigidity of a planetary roller can be improved and the planetary roller type rotation transmission apparatus which can suppress rotation unevenness can be provided.

  At least the following matters will become apparent from the description of the present specification and the accompanying drawings.

A planetary roller type rotation transmission device that shifts and outputs input rotation,
A solar shaft body housed in a housing and rotatable about an axis;
A plurality of planetary rollers that revolve around the solar shaft while rotating by rolling while being pressed against the outer peripheral surface of the solar shaft by a predetermined pressure contact force,
A planetary frame supported by the housing so as to be able to rotate based on a revolving operation of the planetary roller while holding the planetary roller so as to be capable of rotating about a rotation axis via a bearing member;
The planetary roller is provided so as to cover the planetary roller from the outside while being supported by the housing, and the planetary roller rolls on the inner peripheral surface while applying the pressing force to the planetary roller by pressing the planetary roller against the solar shaft body. An elastic ring body,
The planetary roller integrally protrudes in a direction along the rotation axis from a cylindrical rolling part that rolls on the outer peripheral surface of the solar shaft body and the inner peripheral surface of the elastic ring body, and from both end faces of the cylindrical rolling part. And a pair of shaft portions for supporting both ends of the cylindrical rolling portion via the bearing member,
The bearing member is a tapered roller bearing or an angular bearing,
The bearing member includes an inner race that is fitted to the shaft portion of the planetary roller, an outer race that is disposed to face the outer peripheral surface of the inner race, and a space between the races. A plurality of rolling elements that roll in the annular space of
The rolling element is regulated to move inward in the radial direction and in one direction along the rotation axis by the inner raceway, and to move outward in the radial direction by the outer raceway. And movement in the direction opposite to the one direction along the rotation axis is restricted,
In a state where the bearing members are attached to correspond to the pair of shaft portions, respectively, the pair of the bearing members are sandwiched in a direction along the rotation axis by a predetermined portion of the planetary frame, and the outer race ring is A planetary roller type rotation transmission device, wherein a pushing member for pushing toward the inner raceway is screwed to the planetary frame.

  According to such a planetary roller type rotation transmission device, a tapered roller bearing or an angular bearing is used as a bearing member of the planetary roller. Therefore, when the outer race ring is pushed toward the inner race ring along the rotation axis by the pushing member, the rolling element is not only in the direction along the rotation axis by the outer race ring. It is also pushed in the radial direction, and finally the rolling element comes into pressure contact with both the inner raceway and the outer raceway. Accordingly, the clearance between the raceway and the rolling element can be substantially eliminated both in the direction along the rotation axis and in the radial direction, thereby eliminating the rattling associated with the planetary roller. Uneven rotation can be suppressed.

  Moreover, since the cylindrical body is used as the main body of the planetary roller, it is possible to increase the rigidity of the planetary roller itself, and as a result, it is possible to suppress uneven rotation.

  Furthermore, since the planetary roller is supported at both ends, the pressure contact force between the planetary roller and the sun shaft body is applied almost uniformly without contact with each other. Therefore, the displacement of the planetary roller in the direction along the rotation axis is suppressed, and as a result, the rotation unevenness can be suppressed.

Such a planetary roller type rotation transmission device,
The solar shaft body is a cylindrical body that is flat across the range in which the outer peripheral surface is pressed by the planetary roller with a circular cross-section.
The planetary roller rolling portion of the planetary roller is a cylindrical body having a circular cross section and a flat outer circumferential surface along the rotation axis.
It is desirable that annular recesses around the rotation axis are formed on both end faces of the cylindrical rolling part of the planetary roller.

  According to such a planetary roller type rotation transmission device, since the annular recesses are formed on both end faces of the cylindrical rolling part, both end parts in the direction along the rotation axis of the cylindrical rolling part are provided. It becomes easier to elastically deform than the central part. Therefore, the stress distribution of Hertz stress that can occur on the contact surface between the planetary roller and the solar shaft body by the pressure contact force is formed in a mountain shape in which the center is high and the both ends are low in the direction along the rotation axis. This allows the outer periphery of the planetary roller to be maintained in a flat shape while the outer periphery of the planetary roller is crowned (the roll profile is changed to a drum shape, that is, the radius of the planetary roller is changed from the center to the end. It is possible to achieve the same effect as the process of gradually reducing the size as it goes. That is, at the time of rolling, the centripetal force toward the center in the direction along the rotation axis can be increased, and the rolling position of the planetary roller in the direction along the rotation axis can be stabilized.

Such a planetary roller type rotation transmission device,
The cylindrical rolling part of the planetary roller is a solid cylindrical body,
The solar shaft body is preferably a solid cylindrical body.

  According to such a planetary roller type rotation transmission device, the cylindrical roller portion of the planetary roller and the solar shaft body are configured as a solid cylindrical body having no through hole. As a result, the rotation unevenness can be effectively suppressed.

Such a planetary roller type rotation transmission device,
The solar shaft body is supported by the planetary frame by a bearing member disposed in the planetary frame so as to be capable of rotating about the axis.
The bearing member is a tapered roller bearing or an angular bearing,
The bearing member includes an inner race ring fitted to the sun shaft, an outer race ring disposed to face the outer peripheral surface of the inner race ring, and an annular space between the race rings. A plurality of rolling elements that roll
The rolling element is regulated to move inward in the radial direction and in one direction along the axis by the inner race, and to move radially outward by the outer race. And movement in the direction opposite to the one direction along the axis is restricted,
A second push-in member for sandwiching the bearing member in a direction along the shaft core by a predetermined portion of the planetary frame and pushing the inner raceway toward the outer raceway is screwed to the planetary frame. It is desirable that

  According to such a planetary roller type rotation transmission device, a tapered roller bearing or an angular bearing is used as a bearing member of the sun shaft body. Accordingly, when the inner raceway is pushed toward the outer raceway by the second pushing member, the rolling element is not only in the direction along the axis but also in the radial direction by the inner raceway. In the final state, the rolling element is brought into pressure contact with both the inner raceway and the outer raceway. Accordingly, the gap between the race and the rolling element can be substantially eliminated both in the direction along the axis and in the radial direction, thereby eliminating the rattling associated with the solar axis. Rotational unevenness can be suppressed.

Such a planetary roller type rotation transmission device,
The elastic ring body is supported by the housing so as not to move relative to each other via a sleeve member arranged around the entire circumference with a predetermined gap from the outer peripheral surface of the elastic ring body,
It is desirable that the position of the elastic ring body supported by the sleeve member is only the end surface of the elastic ring body in the direction along the rotation axis.

  According to such a planetary roller type rotation transmission device, the support position of the elastic ring body by the sleeve member is set not on the outer peripheral surface of the elastic ring body but on the end face. Therefore, even if the elastic ring body expands or contracts in the radial direction according to the rotation of the planetary frame, the elastic ring body is not given a restraining force from the outer peripheral surface, and according to the rotation of the planetary frame. Thus, the expansion / contraction deformation can be performed freely. As a result, even if the sleeve member is attached to the housing through the sleeve member, the influence of the sleeve member on the pressure contact force is reduced, and uneven rotation due to the sleeve member can be suppressed.

Such a planetary roller type rotation transmission device,
The elastic ring body is a single member integrally formed with a fixing portion that is fixed to the housing while supporting the elastic ring body so as not to move relative to the housing.
The planetary frame is supported by the housing so as to be rotatable by a cross roller bearing interposed between the planetary frame and the housing.
It is desirable that the rolling surface of the rolling element of the cross roller bearing is formed across the fixed portion and the housing.

  According to such a planetary roller type rotation transmission device, since the fixed portion is a part of the elastic ring body, the inner peripheral surface of the elastic ring body and the rolling surface of the fixed portion are simultaneously processed. , Mutual concentricity can be highly enhanced. And here, the inner peripheral surface of the elastic ring body functions as a rolling surface of the planetary roller, while the rolling surface of the fixed part is a rolling member of a cross roller bearing that supports the rotation of the planetary frame. It is a rolling surface. Therefore, by the above simultaneous processing, the concentricity between the rolling surface of the planetary roller and the rotation center of the planetary frame is highly enhanced, and the misalignment between them can be effectively reduced. As a result, it is possible to suppress fluctuations in the preload between the planetary roller and the elastic ring body that may occur due to this misalignment, and to suppress uneven rotation of the planetary frame.

Such a planetary roller type rotation transmission device,
The solar shaft is an input shaft for rotation;
It is desirable that the planetary frame is an output shaft of a rotated rotation.
According to such a planetary roller type rotation transmission device, it can function as a speed reducer.

=== Planet Roller Type Rotation Transmission Device 1 According to First Embodiment ===
2A and 2B are internal structural views of the planetary roller type rotation transmission device 1 according to the first embodiment. 2A shows a cross-sectional view at the center position of the planetary roller 41, and FIG. 2B shows a cross-sectional view along B-C21-B in FIG. 2A. 2A is also a cross-sectional view taken along the line AA in FIG. 2B. Moreover, below, as shown to FIG. 2B, the direction along the axial center C21 of the solar shaft body 21 is also called the front-back direction.

  The planetary roller type rotation transmission device 1 is housed in a cylindrical housing 11 and is press-contacted to the outer peripheral surface of the solar shaft body 21 with a predetermined pressing force, and the solar shaft body 21 is rotatable around an axis C21. While rotating, the four planetary rollers 41 revolving around the sun shaft 21 while rotating, and the planetary rollers 41 are held around the rotation axis C41 via the bearing member 31 so as to be rotatable. A planetary frame 61 supported by the housing 11 so as to be able to rotate based on the revolving operation of the planetary roller 41, and the planetary roller 41 covered from the outside while being supported by the housing 11. An elastic ring body in which the planetary roller 41 rolls on the inner peripheral surface while applying the pressing force to the planetary roller 41 by being pressed against the solar shaft body 21. And a 1, a.

  Here, in order to make this planetary roller type rotation transmission device 1 function as a speed reducer, the rotation input shaft is set to the sun shaft body 21, while the rotation output shaft is set to the planetary frame 61. That is, when rotation is input to the solar shaft body 21, each planetary roller 41 brought into pressure contact with the outer peripheral surface of the solar shaft body 21 changes the outer peripheral surface of the solar shaft body 21 based on rolling friction with the solar shaft body 21. By rolling, it revolves around the solar shaft body 21. At this time, the planetary frame 61 also rotates based on the revolving operation, so that a decelerated rotation is output using the planetary frame 61 as an output shaft. The Incidentally, contrary to the above, if the planetary frame 61 is the rotation input shaft and the rotation output shaft is the sun shaft body 21, the planetary roller type rotation transmission device 1 can also function as a speed increaser.

  The rotation input to the planetary roller type rotation transmission device 1 is made using, for example, a servo motor as a drive source. However, even if high-precision rotation with small rotation unevenness (rotational speed fluctuation) is input by the servo motor, the planetary roller type rotation transmission device 1 has problems in mechanical accuracy such as rattling. In the case where there is rotation, the rotation with uneven rotation is finally output. Therefore, in the planetary roller type rotation transmission device 1 according to the first embodiment, a device for eliminating the cause of the rotation unevenness is applied to each component. Hereinafter, each component will be described.

<Planet frame 61>
The planetary frame 61 has as its main body a cylindrical body in which four accommodation holes 63 for accommodating the four planetary rollers 41 are formed. The planetary frame 61 is housed in the housing 11, and the shaft center C <b> 21, which is the rotation center of the solar shaft body 21, is received by the bearing member 13 provided on the inner peripheral surface of the front end portion of the housing 11. It is supported so that it can rotate on the same axis.

  A so-called cross roller bearing is used as the bearing member 13 and can support a thrust load and a radial load all at once. A cylindrical rolling element 13a used for the cross roller bearing 13 includes a V-shaped groove 13b formed directly on the outer peripheral surface of the planetary frame 61 along the rotation direction of the planetary frame 61, and the V-shaped groove. It rolls by using the V-shaped groove 13c directly formed in the member on the housing 11 and the housing 11 as opposed to 13b as a rolling surface. Therefore, the inner raceway and the outer raceway, which are usually provided as separate members for the purpose of forming the rolling surface, can be omitted, and the problems related to the mounting tolerances associated with the mounting and fixing of these raceways can be eliminated. Uneven rotation is suppressed.

  In addition, from the viewpoint of assembling the planetary roller 41 to the planetary frame 61, the planetary frame 61 has a two-body structure that can be separated into a front half 61a and a rear half 61b. In the frame 61, the accommodation hole 63 for accommodating the planetary roller 41 is formed across the front half 61a and the rear half 61b. When the front half 61a and the rear half 61b are connected and integrated by a fastening member 65 such as a bolt, the portion of the accommodation hole 63 of the front half 61a and the accommodation hole 63 of the rear half 61b opposite to this portion. The parts are integrated into one accommodation hole 63.

  Here, the coaxiality between the portion of the accommodation hole 63 present in the front half portion 61a and the portion of the accommodation hole 63 present in the rear half portion 61b is the same as that of the front half portion 61a and the rear half portion 61b. Is secured in a connected and integrated state, and this coaxiality can be reproduced in subsequent assembly, so that the positioning pin is intruded across the front half 61a and the rear half 61b. A hole (not shown) is formed.

  Further, the front end portion 61c of the planetary frame 61 protrudes forward from the front end edge of the housing 11, so that the planetary frame 61 as the output shaft is connected to the input end of the device to be driven on the front end side. I can do it.

<Planet roller 41>
The planetary rollers 41 are respectively accommodated in the four accommodation holes 63 formed in the planetary frame 61, and the four planetary rollers 41 are arranged point-symmetrically with respect to the axis C <b> 21 of the solar shaft body 21. Yes. Each planetary roller 41 is rotatably supported around a rotation axis C41 parallel to the axis C21 of the solar shaft body 21 via a bearing member 31 provided in the corresponding accommodation hole 63. .

  The planetary roller 41 has a solid cylindrical body 41a (corresponding to a cylindrical rolling part, hereinafter also referred to as a cylindrical body 41a) as a main body in order to increase its rigidity, and the rotation axis C41 of the cylindrical body 41a. From both end surfaces in the direction along the axis (hereinafter also referred to as the rotation axis C41 direction), small-diameter columnar shaft portions 41b and 41b are formed so as to be integral and concentric. One shaft portion 41 b is fitted concentrically to the front bearing member 31 disposed in the accommodation hole 63 of the front half portion 61 a of the planetary frame 61, and the other shaft portion 41 b is the latter half of the planetary frame 61. The rear bearing member 31 disposed in the receiving hole 63 of the portion 61b is fitted concentrically, and the planetary roller 41 is supported at both ends by these bearing members 31 and 31.

  Here, as the bearing member 31, a so-called taper roller bearing is applied. The tapered roller bearing 31 includes an inner race 31a (corresponding to the inner raceway) fitted concentrically with the shaft portion 41b of the planetary roller 41, and the planetary frame 61 while facing the outer peripheral surface of the inner race 31a. Outer race 31b (corresponding to the outer race) and a plurality of tapered rollers 31c (rollers) as rolling elements that roll in an annular space between the pair of races 31a and 31b. And a conical roller). In the inner race 31a, an annular convex portion 31d is formed on the inner edge in the direction of the rotation axis C41 from the rolling surface thereof, whereby the taper roller 31c is arranged in the direction of the rotation axis C41. Inward movement (equivalent to movement in one direction) is restricted. On the other hand, the rolling surface of the outer race 31b is formed as a tapered circumferential surface having a diameter reduced toward the outer side in the direction of the rotation axis C41. Due to this taper gradient, the outer surface of the taper roller 31c in the direction of the rotation axis C41. Movement in the direction (corresponding to movement opposite to the one direction) is restricted.

  In addition, the annular space between the inner race 31a and the outer race 31b has a substantially tapered cylindrical shape that substantially matches the taper gradient of the tapered roller 31c. Therefore, when the outer race 31b is pushed inward in the direction of the rotation axis C41, the outer race 31b is pushed and the taper roller 31c moves inward in the direction of the rotation axis C41. In this case, the taper roller 31c is moved. Is also pushed in the radial direction, and finally the taper roller 31c is pressed against both the inner race 31a and the outer race 31b. Therefore, by pushing the outer race 31b inward in the direction of the rotation axis C41, the gap between the pair of races 31a, 31b and the rolling elements 31c is almost eliminated in both the rotation axis C41 direction and the radial direction. With this, it is possible to eliminate the rattling associated with the planetary roller 41 and to suppress the rotation unevenness.

  The application of the pushing force in the direction of the rotation axis C41 is performed by screwing and rotating the pushing member 67 screwed into the mouth of the accommodation hole 63 of the rear half 61b of the planetary frame 61. That is, when the pushing member 67 is turned in a state where the planetary rollers 41 supported at both ends by the front bearing member 31 and the rear bearing member 31 are arranged in the accommodation hole 63, the pushing member 67 is fed forward like a feed screw mechanism. The outer race 31b of the rear bearing member 31 comes into contact with the outer race 31b, but when further rotated, the outer race 31b, the tapered roller 31c, the inner race 31a, and the planetary roller 41 of the rear bearing member 31 are fed forward by the push-in member 67 Then, the inner race 31a, the taper roller 31c, and the outer race 31b of the front bearing member 31 are pushed forward and finally sent, and the outer race 31b of the front bearing member 31 is finally sent to the bottom 63a of the receiving hole 63. (Corresponding to a predetermined part of the planetary frame) As a result, the pair of bearing members 31, 31 are sandwiched between the push-in member 67 and the bottom 63a of the receiving hole 63, whereby a push-in force in the direction of the rotation axis C41 is applied.

<Solar shaft body 21>
The solar shaft body 21 is a solid cylindrical body whose main body is flat (that is, has the same outer diameter) over the range in which the outer circumferential surface is in pressure contact with the planetary roller 41. Then, in a state of being accommodated in an accommodation hole 69 formed concentrically with the rotation center axis C61 of the planetary frame 61, it is fitted to a pair of bearing members 25, 25 provided in the front half 61a of the planetary frame 61, Thus, the planetary frame 61 is supported so as to be rotatable about the same axis as the rotation center axis C61.

  Specifically, a small-diameter columnar shaft portion 21b is integrally and concentrically formed on the front end portion of the solar shaft body 21 via a step portion 21a. In addition, a rib 69a protruding in an annular shape from the inner peripheral surface is integrally formed in the portion of the accommodation hole 69 facing the shaft portion 21b. And when inserting the said solar shaft body 21 from the back to the front of the accommodation hole 69, while the rear side bearing member 25 is pinched | interposed and fixed between the said level | step-difference part 21a and the said rib 69a, a front side bearing member 25 is fixed by being sandwiched between a fastening member 27 (corresponding to a second pushing member) screwed to the front end of the shaft portion 21b and the rib 69a (corresponding to a predetermined portion of the planetary frame). Needless to say, when the tightening member 27 is screwed and rotated, a pinching force along the direction of the axis C21 is applied to the front bearing member 25, but as a reaction force of the pinching force, the solar shaft 21 Since a tensile axial force acts on the shaft portion 21b, this axial force is transmitted to the step portion 21a, whereby the rear bearing member 25 is also given a pinching force from the step portion 21a.

  Here, a tapered roller bearing is used as the bearing member 25 as in the case of the planetary roller 41. Therefore, when the clamping force acts on the bearing member 25 by the tightening member 27, the taper roller 25c of the bearing member 25 has the inner race 25a (on the inner raceway) based on the same reason as that of the planetary roller 41 described above. Equivalent) and the outer race 25b (corresponding to the outer raceway), whereby a gap between the pair of races 25a, 25b and the rolling element 25c is formed in both the axial center C21 direction and the radial direction. About almost nothing can be done. As a result, the rattling associated with the solar shaft body 21 can be eliminated, and the rotation unevenness can be suppressed.

<Elastic ring body 81>
The elastic ring body 81 is a member for pressing the planetary roller 41 against the solar shaft body 21 with a predetermined pressure contact force for the purpose of stabilizing the rolling of the planetary roller 41 around the solar shaft body 21. The main body is a cylindrical body having a circular cross section. Then, the four planetary rollers are arranged such that the inner peripheral surface of the elastic ring body 81 comes into contact with the outer peripheral surfaces of the four planetary rollers 41 partially protruding outward from the outer peripheral surface of the planetary frame 61. 41 is arranged so as to surround from the outside in the radial direction.

  The inner diameter of the elastic ring body 81 is slightly smaller than the diameter of one perfect circle in which all four planetary rollers 41 of the planetary frame 61 are inscribed in a state where no external force acts on the elastic ring body 81. Is set. Therefore, when the elastic ring body 81 is fitted from the outside of the four planetary rollers 41, a hoop stress is generated in the elastic ring body 81. Based on the hoop stress, each planetary roller 41 has a sun. The shaft body 21 is reliably pressed against the outer peripheral surface and preloaded.

  Further, the elastic ring body 81 is supported by the housing 11 so as not to move relative to the housing 11, whereby each planetary roller 41 rolls on the inner peripheral surface of the elastic ring body 81 based on rolling friction. Move. And with this rolling, the elastic ring body 81 partially repeats the diameter expansion deformation and the diameter reduction deformation. That is, when the planetary roller 41 passes through a predetermined portion of the elastic ring body 81, the predetermined portion undergoes a diameter expansion deformation, and when it passes, the diameter reduction deformation occurs. However, if these deformations are constrained from the outside, this may affect the pressure contact force and cause uneven rotation. Therefore, here, a thin sleeve member 83 with low rigidity is used as a support structure for supporting the elastic ring body 81 on the housing 11, and the support position is set not on the outer peripheral surface of the elastic ring body 81 but on the rear end surface 81 a. is doing.

  Specifically, the sleeve member 83 extends rearward from the housing 11 to the elastic ring body 81, and the inner peripheral surface thereof is located with a predetermined gap between the outer peripheral surface of the elastic ring body 81. Then, from the rear end surface 81a of the elastic ring body 81, a convex portion 81b protruding outward in the radial direction is integrally formed over the entire circumference of the elastic ring body 81 to form a flange portion 81b. The rear end surface of the sleeve member 83 is abutted against the portion 81b and screwed. According to this support structure, since the sleeve member 83 does not contact the outer peripheral surface of the elastic ring body 81, the elastic ring body 81 is not restrained from the sleeve member 83 when the elastic ring body 81 is expanded or contracted. The influence of the sleeve member 83 on the pressure contact force is reduced, and uneven rotation due to the sleeve member 83 is suppressed.

=== Modification of First Embodiment ===
FIG. 3A and FIG. 3B are explanatory views of a modification of the first embodiment, and both drawings show a pressure contact state between the planetary roller 41 and the solar shaft body 21. In these drawings, a part is shown in a broken view.

  As shown in FIG. 3A, in the planetary roller 41 of the first embodiment, both end surfaces in the direction of the rotation axis C41 of the columnar body 41a that is the main body are formed as flat surfaces except for the shaft portion 41b. As shown in FIG. 3B, in this modification, annular recesses 45 having the same shape are formed on both end surfaces of the cylindrical body 41a of the planetary roller 41 for the purpose of stabilizing the rolling position of the planetary roller 41 in the direction of the rotation axis C41. Is different.

  As shown in FIG. 3B, the annular recess 45 has a pair of large and small circular side wall surfaces 45a and 45b centering on the rotation axis C41 of the planetary roller 41, and a bottom wall surface connecting these side wall surfaces 45a and 45b at the bottom. 45c. And the depth of each annular recessed part 45 and 45 is the depth which does not reach the center of the rotating shaft C41 direction, that is, the annular recessed part 45 is not formed in the center part of the rotating shaft C41 direction in the cylindrical main body 41a. The solid part remains.

  Therefore, since both ends of the cylindrical body 41a in the direction of the rotation axis C41 are more easily elastically deformed than the center portion, the Hertz that can be generated on the contact surface between the planetary roller 41 and the solar shaft body 21 by the pressure contact force. From the distribution in which both ends in the direction of the rotation axis C41 as shown in FIG. 3A are increased in a square shape as shown in FIG. 3A, the peak shape in which the center is high in the direction of the rotation axis C41 as shown in FIG. As a result, the planetary roller 41 is maintained in a flat shape (that is, a shape having the same outer diameter) over the entire width in the direction of the rotation axis C41. The outer peripheral surface of 41 is crowned (the roll profile is made into a drum shape, that is, the radius of the planetary roller 41 is gradually decreased from the center toward the end. That processing) can provide the same effect as subjected to. That is, the centripetal force toward the center in the direction of the rotation axis C41 during rolling can be increased, and as a result, the rolling position of the planetary roller 41 with respect to the direction of the rotation axis C41 can be stabilized. It is possible to suppress the rolling direction of the roller 41 from swinging in the direction of the rotation axis C41.

  Incidentally, in general, when the crowning process is performed on the planetary roller 41 of the planetary roller type rotation transmission device 1, a high-precision machining is required in which the diameter difference between the central part and both ends in the direction of the rotation axis C41 is several microns. However, with respect to the processing of the annular recess 45, such high-precision processing is not necessary, and the configuration in which the annular recess 45 is provided has an advantage that the processing accuracy can be reduced and reduced.

=== Planet Roller Type Rotation Transmission Device 1a According to Second Embodiment ===
FIG. 4 is an explanatory diagram of the planetary roller type rotation transmission device 1a according to the second embodiment.
In the first embodiment described above, the solar shaft body 21 is cantilevered by the planetary frame 61 by the bearing members 25 and 25 provided at the front end side of the contact portion of the planetary roller 41 ( In this second embodiment, a bearing member 26 is additionally provided in a portion of the solar shaft body 21 on the rear end side of the contact portion of the planetary roller 41 so that both ends are supported. The main difference is that Other than this, the second embodiment is generally the same as the first embodiment. Therefore, the same components are denoted by the same reference numerals in the drawing, and the description thereof is omitted.

  The bearing member 26 on the rear end side is, for example, a needle bearing, and a plurality of needles 26a that roll in contact with the outer peripheral surface of the sun shaft body 21, and the shaft core C21 of the needle 26a while being in contact with the needles 26a. An outer race 26b provided in the accommodation hole 69 of the planetary frame 61 is provided to restrict the movement in the direction. The solar shaft body 21 is supported at both ends by the bearing member 26 on the rear end side and the bearing member 25 on the front end side at two positions straddling the contact portion of the planetary roller 41 on which the pressing force acts. Further, the rotation of the solar shaft body 21 can be further stabilized.

  According to this configuration, the solar shaft body 21 and the planetary frame 61 are structured to support each other via the bearing member 26 on the rear end side. That is, the planetary frame 61 is also supported by the solar shaft body 21 via the bearing member 26 on the rear end side. Therefore, the bearing member 26 on the rear end side is additionally provided on the bearing member 25 on the front end side described in the first embodiment, so that the planetary frame 61 also has the bearing members 31, 31 of the planetary roller 41. Both ends are supported outside the position 31 in the direction of the rotation axis C41. As a result, the rotation of the planetary frame 61 is stabilized.

  Further, the additional installation of the bearing member 26 on the rear end side stabilizes the rotation of the rear end portion 61d of the planetary frame 61 in particular, and suppresses uneven rotation. Therefore, according to this configuration, the sensor member 71 such as an encoder for detecting the rotation speed of the planetary frame 61 can be attached not only to the front end portion 61c of the planetary frame 61 but also to the rear end portion 61d. Accordingly, the degree of freedom of the attachment position of the sensor member 71 can be improved.

  By the way, in this 2nd Embodiment, although the output rotating shaft 93 of the servomotor 91 is directly connected to the rear-end part of the solar shaft body 21, in the case of the attachment to the housing 11 of the servomotor 91 in this case, If the output rotation shaft 93 is attached with an inclination, the sun shaft body 21 is also inclined following the output rotation shaft 93, which may cause uneven rotation. Therefore, preferably, as shown in FIG. 4, for example, the output rotation shaft 93 of the servo motor 91 and the sun shaft body 21 may be connected by a diaphragm type coupling 95, and then the coupling 95 is connected to the servo motor. It is possible to effectively prevent the solar shaft body 21 from being inclined by absorbing the influence of the inclination of the output rotation shaft 93 of 91.

=== Other Embodiments ===
As mentioned above, although embodiment of this invention was described, this invention is not limited to this embodiment, The deformation | transformation as shown below is possible.

(A) In the above-described embodiment, the tapered roller bearing is exemplified as the bearing member 31 of the planetary roller 41. However, an angular bearing may be used. This angular bearing is a type of ball bearing that uses a sphere as a rolling element, and the rolling surface of the outer race and the rolling surface of the inner race each have a gradient with respect to the rotational axis direction of the planetary roller. It is formed by attaching. Therefore, even with this angular bearing, the same operational effects as those of the above-described tapered roller bearing can be achieved.

(B) In the above-described embodiment, the tapered roller bearing is exemplified as the bearing member 25 of the solar shaft body 21; however, an angular bearing may be used, and this angular bearing is the same as the above-described tapered roller bearing. An effect can be produced.

(C) In the above-described embodiment, the solid cylindrical body 41a and the solid cylindrical body are illustrated as the main body of the planetary roller 41 and the main body of the solar shaft body 21, respectively. For example, a thin through hole may be formed in the cylindrical body 41a of the planetary roller 41 and the cylindrical body that is the main body of the solar shaft body as a supply path for supplying lubricating oil to the bearing members 31, 25 and the like.

(D) In the first embodiment described above (FIGS. 2A and 2B), the sleeve member 83 for supporting the elastic ring body 81 on the housing 11 is formed separately from the elastic ring body 81, However, the present invention is not limited to this, and the elastic ring body 81 and the sleeve member 83 are combined into a single member 181 (single member) as shown in FIGS. 5A and 5B. It may be configured.

  That is, the elastic ring body 181 shown in FIGS. 5A and 5B includes an elastic ring body equivalent portion 181a that functions as the elastic ring body 81 located at the rear, and an elastic ring body equivalent portion 181a located at the front. 11 and a cylindrical fixing portion 181b provided concentrically with the elastic ring body equivalent portion 181a and a thin-walled portion connecting between the elastic ring body equivalent portion 181a and the cylindrical fixing portion 181b. And a sleeve portion 181c. The cylindrical fixing portion 181 b is bolted to the housing 11 in a state where the elastic ring body equivalent portion 181 a is fitted from the outside of the four planetary rollers 41.

  At this time, the front end portion of the inner peripheral surface of the cylindrical fixing portion 181b functions as a part of the V-shaped groove 13c on the housing 11 side related to the cross roller bearing as the bearing member 13 of the planetary frame 61. That is, one rolling surface 13d of the V-shaped groove 13c is formed in the housing 11, while the other rolling surface 13e is formed at the front end portion of the inner peripheral surface of the cylindrical fixing portion 181b. Has been. In a state where the cylindrical fixing portion 181b is bolted to the housing 11, the rolling surfaces 13d and 13e are connected to form a V-shaped groove 13c.

  According to such a configuration, the misalignment between the rolling surface of the planetary roller 41 and the rotation center axis C61 of the planetary frame 61 in the elastic ring body 181 is effectively reduced, thereby causing the misalignment. Thus, fluctuations in the preload between the planetary roller 61 and the elastic ring body 181 that can occur can be suppressed, and as a result, rotation unevenness of the planetary frame 61 as the output shaft can be effectively suppressed.

  Details are as follows. First, according to the above configuration, since the elastic ring body equivalent portion 181a and the cylindrical fixing portion 181b are inseparable members, the inner peripheral surface 181d of the elastic ring body equivalent portion 181a and the V-shape of the cylindrical fixing portion 181b. The rolling surface 13e of the groove 13c can be simultaneously processed by a lathe or the like, and thereby the concentricity thereof can be highly enhanced. The former inner peripheral surface 181d is a rolling surface of the planetary roller 41, and the latter rolling surface 13e of the latter V-shaped groove 13c is a cross roller that supports the planetary frame 61 so that it can rotate. It is a part of the bearing 13. Therefore, the misalignment between the rolling surface of the planetary roller 41 and the rotation center axis C61 of the planetary frame 61 can be effectively reduced. Further, according to the above configuration, since the assembly itself of the elastic ring body 81 and the sleeve member 83 required in the first embodiment (FIGS. 2A and 2B) is eliminated, these assembly errors are eliminated, and as a result, The above misalignment is further reduced.

It is sectional drawing which shows the conventional planetary roller type rotation transmission apparatus 101 by a partial side view. 2A and 2B are internal structural views of the planetary roller type rotation transmission device 1 according to the first embodiment. FIG. 2A shows a cross-sectional view at the center position of the planetary roller 41, and FIG. FIG. 2B is a cross-sectional view taken along line B-C21-B in FIG. 2A. FIG. 3A and FIG. 3B are explanatory views of a modification of the first embodiment, and both drawings show a pressure contact state between the planetary roller 41 and the solar shaft body 21. It is explanatory drawing of the planetary roller type rotation transmission apparatus 1a which concerns on 2nd Embodiment. 5A and 5B are internal structural views of a planetary roller type rotation transmission device 1b according to another embodiment. FIG. 5A shows a cross-sectional view at the center position of the planetary roller 41, and FIG. , B-C21-B sectional view in FIG. 5 is shown.

Explanation of symbols

1 planetary roller type rotation transmission device, 1a planetary roller type rotation transmission device,
1b Planetary roller type rotation transmission device, 11 housing,
13 bearing member, 13a rolling element, 13b V-shaped groove, 13c V-shaped groove,
13d rolling surface, 13e rolling surface, 21 solar shaft body, 21a stepped portion, 21b shaft portion,
25 bearing members, 25a inner race (inner race),
25b outer race (outer raceway), 25c taper roller (rolling element),
26 bearing member, 26a needle, 26b outer race,
27 Tightening member (second pushing member), 31 Bearing member,
31a inner race (inner race), 31b outer race (outer race), 31c taper roller (rolling element), 31d annular convex part,
41 planetary roller, 41a cylindrical body (cylindrical rolling part), 41b shaft part,
45 annular recess, 45a side wall surface, 45b side wall surface, 45c bottom wall surface,
61 planetary frame, 61a first half, 61b second half, 61c front end,
61d rear end portion, 63 receiving hole, 63a bottom portion (predetermined portion), 65 fastening member,
67 pushing member, 69 accommodation hole, 69a rib (predetermined part),
71 sensor member, 81 elastic ring body, 81a rear end surface,
81b Convex part (flange part), 83 sleeve member, 91 servo motor,
93 Output rotating shaft, 95 coupling, 181 elastic ring body,
181a elastic ring body equivalent part, 181b cylindrical fixing part (fixing part),
181c sleeve portion, 181d inner peripheral surface,
C21 axis, C41 rotation axis, C61 rotation center axis

Claims (7)

A planetary roller type rotation transmission device that shifts and outputs input rotation,
A solar shaft body housed in a housing and rotatable about an axis;
A plurality of planetary rollers that revolve around the solar shaft while rotating by rolling while being pressed against the outer peripheral surface of the solar shaft by a predetermined pressure contact force,
A planetary frame supported by the housing so as to be able to rotate based on a revolving operation of the planetary roller while holding the planetary roller so as to be capable of rotating about a rotation axis via a bearing member;
The planetary roller is provided so as to cover the planetary roller from the outside while being supported by the housing, and the planetary roller rolls on the inner peripheral surface while applying the pressing force to the planetary roller by pressing the planetary roller against the solar shaft body. An elastic ring body,
The planetary roller integrally protrudes in a direction along the rotation axis from a cylindrical rolling portion that rolls on the outer peripheral surface of the solar shaft body and the inner peripheral surface of the elastic ring body, and from both end surfaces of the cylindrical rolling portion. And a pair of shaft portions for supporting both ends of the cylindrical rolling portion via the bearing member,
The bearing member is a tapered roller bearing or an angular bearing,
The bearing member includes an inner race that is fitted to the shaft portion of the planetary roller, an outer race that is disposed to face the outer peripheral surface of the inner race, and a space between the races. A plurality of rolling elements that roll in the annular space of
The rolling element is regulated to move inward in the radial direction and in one direction along the rotation axis by the inner raceway, and to move outward in the radial direction by the outer raceway. And movement in the direction opposite to the one direction along the rotation axis is restricted,
In a state where the bearing members are attached to correspond to the pair of shaft portions, the pair of the bearing members are sandwiched in a direction along the rotation axis by a predetermined portion of the planetary frame, and the outer race ring is A planetary roller type rotation transmission device, wherein a pushing member for pushing toward the inner raceway is screwed to the planetary frame. The planetary roller type rotation transmission device according to claim 1,
The solar shaft body is a cylindrical body that is flat across the range in which the outer peripheral surface is pressed by the planetary roller with a circular cross-section.
The planetary roller rolling portion of the planetary roller is a cylindrical body having a circular cross section and a flat outer circumferential surface along the rotation axis.
The planetary roller type rotation transmission device characterized in that annular recesses around the rotation axis are formed on both end faces of the cylindrical rolling part of the planetary roller. The planetary roller type rotation transmission device according to claim 2,
The cylindrical rolling part of the planetary roller is a solid cylindrical body,
The planetary roller type rotation transmission device, wherein the solar shaft body is a solid cylindrical body. The planetary roller type rotation transmission device according to any one of claims 1 to 3,
The solar shaft body is supported by the planetary frame by a bearing member disposed in the planetary frame so as to be capable of rotating about the axis.
The bearing member is a tapered roller bearing or an angular bearing,
The bearing member includes an inner race ring fitted to the sun shaft, an outer race ring disposed to face the outer peripheral surface of the inner race ring, and an annular space between the race rings. A plurality of rolling elements that roll
The rolling element is regulated to move inward in the radial direction and in one direction along the axis by the inner race, and to move radially outward by the outer race. And movement in the direction opposite to the one direction along the axis is restricted,
A second push-in member for sandwiching the bearing member in a direction along the shaft core by a predetermined portion of the planetary frame and pushing the inner raceway toward the outer raceway is screwed to the planetary frame. Planetary roller type rotation transmission device characterized by being made. The planetary roller type rotation transmission device according to any one of claims 1 to 4,
The elastic ring body is supported by the housing so as not to move relative to each other via a sleeve member arranged around the entire circumference with a predetermined gap from the outer peripheral surface of the elastic ring body,
A planetary roller type rotation transmission device, wherein the elastic ring body is supported by the sleeve member only on an end surface of the elastic ring body in a direction along the rotation axis. The planetary roller type rotation transmission device according to any one of claims 1 to 4,
The elastic ring body is a single member integrally formed with a fixing portion that is fixed to the housing while supporting the elastic ring body so as not to move relative to the housing.
The planetary frame is supported by the housing so as to be rotatable by a cross roller bearing interposed between the planetary frame and the housing.
A planetary roller type rotation transmission device, wherein a rolling surface of a rolling element of the cross roller bearing is formed across the fixed portion and the housing. The planetary roller type rotation transmission device according to any one of claims 1 to 6,
The solar shaft is an input shaft for rotation;
A planetary roller type rotation transmission device, wherein the planetary frame is an output shaft of a rotated rotation.

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