JP2005180636A - Bearing for planetary gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and simple bearing for a planetary gear capable of absorbing positioning error of the planetary gear without complicating a structure of a carrier. <P>SOLUTION: This bearing 20 for the planetary gear is used in a planetary gear device wherein a sun gear 12 is mounted on a center of a ring-shaped internal gear 11, a plurality of planetary gears 15 are mounted between the internal gear 11 and the sun gear 12 through the carrier 13, and the plurality of planetary gears 15 are engaged with the internal gear 11 and the sun gear 12, and mounted between a supporting shaft 16 mounted on the carrier 13 and the planetary gear 15. This bearing 20 for the planetary gear comprises an inner ring 25 fitted to the supporting shaft 16, and an outer ring 26 fitted to the planetary gear 15, and at least one of the inner and outer rings is constituted to lower the radial rigidity. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a planetary gear bearing, and more particularly to a planetary gear bearing used in a planetary gear device used in a general industrial machine.

The planetary gear unit can effectively obtain a high gear ratio, the input shaft and the output shaft are coaxial, and can be made more compact than a parallel gear unit. Many are used.
In particular, this planetary gear device is widely known in which a plurality of (usually 3 to 4) planetary gears are connected via a carrier between an internal gear and a sun gear at the center thereof.
A plurality of planetary gears are rotatably supported via bearings on a support shaft provided on the carrier. The planetary gear rotates and revolves while meshing with both the internal gear and the sun gear.

A planetary gear device using planetary gears is shown in FIG. In the planetary gear device 100, the power input from the input shaft 101 and the carrier 102 is transmitted to the planetary gear 104 through the support shaft 103.
Specifically, the planetary gear 104 is rotatably supported with respect to the support shaft 103 by fitting the planetary gear 104 to the support shaft 103 via a bearing (not shown). The power transmitted from the support shaft 103 to the planetary gear 104 acts as a radial load (that is, a force applied in the radial direction of the bearing) on the bearing.

The planetary gear 104 revolves while meshing with the fixed internal gear 105 to transmit power to the sun gear 106. Power is transmitted from the sun gear 106 to the output shaft 107.
Here, the carrier 102 is formed so as to support the support shaft 103 of the planetary gear device 100 at both ends 103A and 103B.
Supporting the support shaft 103 at both ends 103A and 103B prevents the support shaft 103 from elastically deforming obliquely even when large power is transmitted by the planetary gear device 100.

Although the planetary gear device 100 is compact and can provide a high gear ratio, it is difficult to accurately position the planetary gears 104 due to mounting errors and processing errors. For this reason, there is a possibility that force is applied to each planetary gear 104 unevenly.
That is, when the planetary gears 104 are arranged at equal intervals between the internal gear 105 and the sun gear 106 as shown in FIG. 11, the positions of the planetary gears 104 are both the internal gear 105 and the sun gear 106. It is a condition that they mesh at the same time, and is preferably determined at the best position per tooth.

However, the mounting position of each planetary gear 104 is restricted by the support shaft 103 fitted to the carrier 102. If the position accuracy of the support shaft 103 is poor, the contact of the planetary gear 104 may be uneven.
When the planetary gear 104 has uneven teeth, a force is applied to the planetary gear 104 having strong teeth.
For this reason, when the planetary gear 104 having a strong tooth contact is elastically deformed, a force is applied to the other planetary gears 104 for the first time.

FIG. 11 shows a state where all of the three planetary gears 104 are ideally meshed with the internal gear 105.
FIG. 12 shows a state in which the lower two planetary gears 104 out of the three planetary gears 104 mesh with the internal gear 105 in a state where the tooth contact is strong.
FIG. 13 shows a state in which only one upper planetary gear 104 out of the three planetary gears 104 meshes with the internal gear 105 in a state where the tooth contact is strong.

In FIG. 12, the upper two planet gears 104 receive a small force via the sun gear 106 so that the large force received from the internal gear 105 is dispersed. It is preferable to travel to the planetary gear 104 in the direction of the arrow.
In FIG. 13, two lower forces receiving a small force via the sun gear 106 so that one large planetary gear 104 disperses a large force received from the internal gear 105. It is preferable to travel to the planetary gear 104 in the direction of the arrow.

However, since the position of each planetary gear 104 is constrained by the support shaft 103 (see FIG. 1) of the carrier 102, a large force received by a part of the planetary gears 104 is distributed to the other planetary gears 104. Thus, it is difficult to correct the position of the planetary gear 104.
For this reason, during the operation of the planetary gear device 100, the force applied to the planetary gear 104 having a strong tooth contact always increases, which causes damage to the tooth surface 108 (see FIG. 14 described later), the planetary gear 104 and the support shaft. This is a cause of damage to the bearing interposed between them.

There has been proposed a planetary gear device 100 that eliminates damage to the tooth surface 108 and causes of bearing damage (see, for example, Patent Documents 1 to 3).
Japanese Utility Model Publication No. 5-45297 Japanese Utility Model Publication No. 6-67949 Japanese Patent Laid-Open No. 8-170695

Japanese Utility Model Laid-Open No. 5-45297 discloses a technique in which a slight gap is formed between a support shaft of a planetary gear and a bearing, and an oil film made of lubricating oil is formed in the gap.
As a result, the planetary gears can move in the radial direction, and the force applied to each planetary gear is evenly distributed.

However, there is a slight gap between the support shaft and the bearing, and the oil film thickness is as small as 15 to 20 μm.
For this reason, in a large planetary gear device used for an industrial machine, it is difficult to manage the fit between the support shaft and the bearing with a slight gap.

  Furthermore, the large planetary gear device has a large planetary gear backlash of several hundred μm, and even if a slight gap is formed between the support shaft and the bearing, it cannot absorb a large backlash. It is difficult to disperse such force effectively.

Japanese Unexamined Utility Model Publication No. 6-67949 discloses a technique in which an elastic bush is fitted to the outer peripheral portion of a bearing fitted to the inner diameter of the planetary gear.
As a result, the planetary gears can move in the radial direction, and the force applied to each planetary gear is evenly distributed.

However, this technique inserts a bearing into the support shaft and further inserts an elastic bush into the bearing, so that the inner diameter of the planetary gear increases. For this reason, a planetary gear may become thin, and there exists a possibility of increasing a gear deformation.
That is, it is conceivable that a force is applied in the revolution direction (arrow direction) of the planetary gear 104 indicated by the imaginary line in FIG. 14, and the planetary gear 104 is deformed as indicated by the solid line.
As the planetary gear 104 is deformed, the meshing tooth surface 108 of the planetary gear 104 apparently decreases in meshing rate, and the force applied to the toothing surface 108 increases.
For this reason, it is unsuitable for the large planetary gear apparatus 100 which transmits a big motive power.

  Further, the technique disclosed in Japanese Patent Laid-Open No. 817095/1990 discloses an elastic structure for the support portion of the support shaft. Thereby, the position error of the planetary gear is absorbed, the movement of the planetary gear in the radial direction is enabled, and the force applied to each planetary gear is evenly distributed.

However, this technique requires a carrier having a complicated structure such as a notch hole or a pin in order to make the support portion of the support shaft an elastic structure.
For this reason, it takes time to examine the strength of the carrier, which hinders productivity.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to achieve a compact and simple planetary gear that can absorb a positional error of the planetary gear without complicating the structure of the carrier. It is to provide a bearing.

  In order to achieve the above-described object, the present invention provides a sun gear at the center of a ring-shaped internal gear, and a plurality of planetary gears are arranged between the internal gear and the sun gear via a carrier, A planetary gear having a plurality of planetary gears meshed with an internal gear and a sun gear, a planetary gear bearing interposed between the support shaft provided in the carrier and the planetary gear, and fitted to the support shaft The inner ring and the outer ring fitted to the planetary gear are provided, and at least one of the inner and outer rings is configured to have low radial rigidity.

In the planetary gear bearing configured as described above, the planetary gear is supported by the planetary gear bearing, and at least one of the inner ring and the outer ring of the planetary gear bearing is configured to have low radial rigidity.
As a result, the planetary gear can be moved in the radial direction, and the position error of the planetary gear is absorbed.

Further, by providing the planetary gear bearing itself with a portion that absorbs the position error of the planetary gear, a gap for absorbing the error between the planetary gear bearing and the planetary gear inner diameter as in the prior art, There is no need to provide them separately.
In addition, the damping effect by the elastic structure can contribute to the reduction of vibration and noise generated when the planetary gear is engaged.

  The present invention is characterized in that a circumferential groove is provided on the inner peripheral surface of the inner ring and the outer peripheral surface of the outer ring so that the thickness of at least one of the inner ring and the outer ring is reduced in the center in the axial direction. Yes.

By reducing the thickness of the inner ring and the outer ring at the center in the axial direction, the inner ring and the outer ring are configured as both end support beams. By using both-end support beams, elastic deformation at the center in the axial direction of the inner ring and the outer ring is facilitated.
As a result, the planetary gear can be moved in the radial direction, and the position error of the planetary gear is absorbed.

In addition, the strength is studied in a short time because it is a simple structure in which a groove is formed on the inner peripheral surface of the inner ring and the outer peripheral surface of the outer ring to make it thinner. Productivity can be increased by conducting a strength study in a short time.
Furthermore, since it is a simple structure which only forms a groove part in the inner peripheral surface of an inner ring | wheel or the outer peripheral surface of an outer ring | wheel, the compactness and simplification of the planetary gear bearing can be achieved.

  In the present invention, an elastic body is provided in the groove, and the elastic body is brought into contact with an outer peripheral surface of the support shaft to which the bearing is fitted or an inner peripheral surface of the planetary gear to which the bearing is fitted. It is characterized by that.

An elastic body was provided in the groove. Therefore, it is possible to easily deform the inner ring and the outer ring in the radial direction by elastically deforming the elastic body only by providing a slight gap between the outer peripheral surface of the support shaft and the inner ring or between the inner peripheral surface of the planetary gear and the outer ring. It can be moved.
As a result, the planetary gear can be moved in the radial direction, and the position error of the planetary gear is absorbed.
It is possible to absorb the position error of the planetary gear by simply making the outer peripheral surface of the support shaft slightly smaller and the inner peripheral surface of the planetary gear slightly larger.
Thereby, the compactness and simplification of the planetary gear bearing can be achieved.

According to the present invention, by providing the bearing itself with a portion that absorbs the positional error of the planetary gear, the inner diameter of the planetary gear can be suppressed, the thinning of the planetary gear can be prevented, and the life can be extended. can get.
Furthermore, by providing the bearing itself with a portion that absorbs the positional error of the planetary gear, when the present invention is applied to a conventional planetary gear device, only the planetary gear bearing needs to be replaced. This eliminates the need for design changes and additional processing of the peripheral members, and allows the present invention to be easily applied to conventional planetary gear devices without cost.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. 1A is a schematic diagram of a planetary gear device provided with a planetary gear bearing according to the present invention, FIG. 1B is a front view of the planetary gear device, and FIGS. 2 to 9 are planetary gear bearings according to the present invention. It is sectional drawing which shows 1st-8th embodiment of this.

As shown in FIGS. 1A and 1B, the planetary gear device 10 includes a ring-shaped internal gear 11, a sun gear 12 provided at the center thereof, and the internal gear 11 and the sun gear 12. And a plurality of (three as an example) planetary gears 15 provided via a carrier 13.
The planetary gear 15 is rotatably fitted to a support shaft 16 provided on the carrier 13 via a planetary gear bearing 20.

According to the planetary gear device 10, the power in the direction of arrow A is transmitted from the input shaft 21 to the carrier 13, and the power transmitted to the carrier 13 is transmitted to the planetary gear 15 via the support shaft 16.
By transmitting power to the planetary gear 15, the planetary gear 15 revolves in the direction of arrow B while meshing with the fixed internal gear 11, rotates in the direction of arrow C, and transmits power to the sun gear 12. Thus, power is transmitted from the sun gear 12 to the output shaft 22 in the direction of arrow D.

Here, considering that large power is transmitted by the planetary gear device 10, the carrier 13 is formed so as to support the support shaft 16 at both ends 16A and 16B as shown in FIG.
By supporting the ends 16A and 16B of the support shaft 16 with the carrier 13, the support shaft 16 is prevented from being tilted by the force in the revolution direction acting on the support shaft 16.

A planetary gear bearing 20 according to the first embodiment shown in FIG. 2 has a rolling element 28 disposed between an inner ring 25 and an outer ring 26 via a cage 27, and is curved on an inner peripheral surface 29 of the inner ring 25. A groove portion 29A is formed in the circumferential direction.
The wall thickness T1 of the axial center portion 25A of the inner ring 25 is reduced, and the inner ring 25 is configured as a both-end support beam. By using the inner ring 25 as a support beam at both ends, the elastic deformation of the axial central portion 25A of the inner ring 25 is facilitated.

That is, the rigidity of the inner ring 25 in the radial direction (the radial direction of the support shaft 16) is reduced.
By reducing the rigidity, the inner ring 25 can be elastically deformed in the radial direction. Thereby, the planetary gear 15 shown in FIG. 1 can move in the radial direction, and the position error of the planetary gear 15 is absorbed.

Therefore, for example, when the lower two planetary gears 15 among the three planetary gears 15 shown in FIG. 1B receive a large force from the internal gear 11, this large force is reduced to a small force. This is transmitted to the upper planetary gear 15 that is being received and is evenly distributed to the three planetary gears 15.
Therefore, all the three planetary gears 15 can be meshed with the internal gear 11 evenly.

Also, as shown in FIG. 2, by forming a curved groove 29A on the inner peripheral surface 29 of the inner ring 25, it is possible to provide the planetary gear bearing 20 itself with a portion that absorbs the positional error of the planetary gear 15. become.
Therefore, the inner diameter of the planetary gear 15 can be kept small, the planetary gear 15 can be prevented from being thinned, and the life can be extended.

In addition, by adjusting the depth and width of the groove 29A, the amount of elastic deformation per unit, that is, radial rigidity can be adjusted, and appropriate rigidity can be obtained according to use conditions.
In addition, the damping effect by the elastic structure can contribute to the reduction of vibration and noise generated when the planetary gear 15 is engaged.

  Hereinafter, the planetary gear bearings of the second to eighth embodiments will be described with reference to FIGS. In the planetary gear bearings of the second to eighth embodiments, the same members as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

A planetary gear bearing 30 according to the second embodiment shown in FIG. 3 has a rolling element 28 disposed between an inner ring 31 and an outer ring 26 via a cage 27, and a groove portion is formed on an inner peripheral surface 32 of the inner ring 31. 32A is formed in the circumferential direction, and the inner ring cross-sectional shape is substantially U-shaped.
The axial center portion 31A of the inner ring 31, specifically, the thickness T2 in the range H of the axial center portion 31A is reduced, and the inner ring 31 is configured as a support beam at both ends. By using the inner ring 31 as both-end support beams, the rigidity of the inner ring 31 in the radial direction is reduced as in the first embodiment.

By reducing the rigidity, the inner ring 31 can be elastically deformed in the radial direction. Thereby, the planetary gear 15 shown in FIG. 1 can move in the radial direction, and the position error of the planetary gear 15 is absorbed.
Therefore, according to the planetary gear bearing 30 of the second embodiment, the same effect as that of the first embodiment can be obtained.

  A planetary gear bearing 35 according to the third embodiment shown in FIG. 4 includes a rolling element 28 disposed between an inner ring 36 and an outer ring 26 via a retainer 27. A groove portion is formed on an inner peripheral surface 37 of the inner ring 36. 37A is formed in the circumferential direction, the inner ring cross-sectional shape is substantially U-shaped, and a plurality of narrow groove portions 38 are formed in the groove portion 37A at regular intervals in the circumferential direction.

Thereby, the thickness T3 of the narrow groove portion 38 in the groove portion 37A is particularly thin, and the radial rigidity of the inner ring 36 is reduced.
By providing a plurality of narrow grooves 39 in the groove 37A, the amount of elastic deformation per unit, that is, radial rigidity can be adjusted, and appropriate rigidity can be obtained according to the use conditions.

By reducing the rigidity, the ring 36 can be elastically deformed in the radial direction as in the first embodiment. Accordingly, the planetary gear 15 shown in FIG. 1 can move in the radial direction, and the position error of the planetary gear 15 is absorbed.
Therefore, according to the planetary gear bearing 35 of the third embodiment, the same effect as that of the first embodiment can be obtained.

The planetary gear bearing 40 of the fourth embodiment shown in FIG. 5 has a rolling element 28 disposed between an inner ring 44 and an outer ring 41 via a cage 27, and is curved on the outer peripheral surface 42 of the outer ring 41. The groove portion 42A is formed in the circumferential direction.
The wall thickness T4 of the central portion 41A in the axial direction of the outer ring 41 is reduced, and the outer ring 41 is configured as a both-end support beam. By using the outer ring 41 as a support beam at both ends, the elastic deformation of the central portion 41A in the axial direction of the outer ring 41 is facilitated.

That is, the radial rigidity of the outer ring 41 is reduced. By reducing the rigidity, the outer ring 41 can be elastically deformed in the radial direction.
Accordingly, the planetary gear 15 shown in FIG. 1 can move in the radial direction, and the position error of the planetary gear 15 is absorbed.

  A planetary gear bearing 45 according to the fifth embodiment shown in FIG. 6 has a rolling element 28 disposed between an inner ring 46 and an outer ring 26 via a cage 27, and a groove portion is formed on an inner peripheral surface 47 of the inner ring 46. 47A is formed in the circumferential direction, and a spring material (elastic body) 48 is provided in the groove portion 47A in the circumferential direction.

The spring material 48 is brought into contact with the outer peripheral surface 16C of the support shaft 16 (see also FIG. 1) to which the planetary gear bearing 45 is fitted.
Here, a slight gap is provided between the outer peripheral surface 16 </ b> C of the support shaft 16 and the inner peripheral surface 47 of the inner ring 46.

The thickness T5 of the groove 47A of the inner ring 46 is reduced, and the radial rigidity of the inner ring 46 is reduced.
In addition, since the spring material (elastic body) 48 is provided in the groove 47 </ b> A, the gap between the inner ring 46 and the support shaft 16 can be substantially evenly secured by the spring force of the spring material (elastic body) 48.
Since two types of elastic deformation are possible by elastic deformation of the inner ring 46 and elastic deformation of the spring material (elastic body) 48, a large amount of movement in the radial direction can be secured.

  Thereby, the positional error of the planetary gear 15 shown in FIG. 1 is more reliably absorbed, and the planetary gear 15 can be moved in the radial direction.

  A planetary gear bearing 50 according to the sixth embodiment shown in FIG. 7 has a rolling element 28 disposed between an inner ring 51 and an outer ring 26 via a retainer 27, and is substantially connected to an inner peripheral surface 52 of the inner ring 51. A circumferential groove 52A is formed in a letter shape, and a rubber material or a synthetic resin material (elastic body) 53 is provided in the circumferential groove 52A.

The rubber material or the synthetic resin material 53 is brought into contact with the outer peripheral surface 16C of the support shaft 16 (see also FIG. 1) to which the planetary gear bearing 50 is fitted.
Here, a slight gap is provided between the outer peripheral surface 16 </ b> C of the support shaft 16 and the inner peripheral surface 52 of the inner ring 51.

The thickness T6 of the groove 52A of the inner ring 51 is reduced, and the radial rigidity of the inner ring 51 is reduced.
In addition, since the rubber material or synthetic resin material (elastic body) 53 is provided in the groove 52A, a gap is formed between the inner ring 51 and the support shaft 16 by the spring force of the rubber material or synthetic resin material (elastic body) 53. It can be secured almost evenly.

Therefore, two types of elastic deformation are possible by elastic deformation of the inner ring 51 and elastic deformation of the rubber material or the synthetic resin material (elastic body) 53, so that a large amount of movement in the radial direction can be secured.
Thereby, the positional error of the planetary gear 15 shown in FIG. 1 is more reliably absorbed, and the planetary gear 15 can be moved in the radial direction.
Therefore, according to the planetary gear bearing 50 of the sixth embodiment, the same effect as that of the fifth embodiment can be obtained.

  A planetary gear bearing 55 according to the seventh embodiment shown in FIG. 8 has a rolling element 28 disposed between an inner ring 56 and an outer ring 26 via a retainer 27. Circumferential grooves 57A are formed at predetermined intervals, and a rubber material or a synthetic resin material (elastic body) 58 is provided in the pair of grooves 57A.

The rubber material or the synthetic resin material 58 is brought into contact with the outer peripheral surface 16C of the support shaft 16 (see also FIG. 1) to which the planetary gear bearing 55 is fitted.
Here, a slight gap is provided between the outer peripheral surface 16 </ b> C of the support shaft 16 and the inner peripheral surface 57 of the inner ring 56.

By providing a rubber material or a synthetic resin material 58 in the gap between the support shaft 16 and the inner ring 56, the rubber material or the synthetic resin material 58 can be elastically deformed to move the inner ring 56 in the radial direction. Become.
Accordingly, the planetary gear 15 shown in FIG. 1 can move in the radial direction, and the position error of the planetary gear 15 is absorbed.
Therefore, according to the planetary gear bearing 55 of the seventh embodiment, the same effect as that of the fifth embodiment can be obtained.

  The planetary gear bearing 60 according to the eighth embodiment shown in FIG. 9 has a rolling element 28 disposed between an inner ring 44 and an outer ring 62 via a cage 27, and is arranged on the outer circumferential surface 63 of the outer ring 62 in the circumferential direction. 63A is formed, and a rubber material or a synthetic resin material (elastic body) 64 is provided in the circumferential groove 63A.

The rubber material or the synthetic resin material 64 is brought into contact with the inner peripheral surface 15A of the planetary gear 15 (see also FIG. 1) to which the planetary gear bearing 60 is fitted.
Here, a slight gap is provided between the inner peripheral surface 15 </ b> A of the planetary gear 15 and the outer peripheral surface 63 of the outer ring 62.

The thickness T8 of the groove 63A of the outer ring 62 is reduced, and the radial rigidity of the outer ring 62 is reduced.
In addition, since a rubber material or synthetic resin material (elastic body) 64 is provided in the groove 63A, a gap is formed between the outer ring 62 and the planetary gear 15 by the spring force of the rubber material or synthetic resin material (elastic body) 64. It can be secured almost evenly.

Therefore, since two types of elastic deformation are possible by elastic deformation of the outer ring 62 and elastic deformation of the rubber material or synthetic resin material (elastic body) 64, a large amount of movement in the radial direction can be ensured.
Accordingly, the planetary gear 15 shown in FIG. 1 can move in the radial direction, and the position error of the planetary gear 15 is more reliably absorbed.

In the above-described embodiment, an example in which the number of planetary gears 15 is three has been described. However, the number of planetary gears 15 is not limited to this.
Moreover, in the said embodiment, although the spring material 48, the rubber material, and the synthetic resin materials 53, 58, and 64 were illustrated as an elastic body, it is not restricted to this, It is also possible to use another elastic body.

  Further, in the above-described embodiment, the example in which power is input from the input shaft 21 of the planetary gear device 10 and the power is output from the output shaft 22 has been described, but the present invention is not limited to this. It is also possible to use the planetary gear unit 10 as a speed reducer by inputting power from the shaft 22 and outputting power from the input shaft 21.

  Furthermore, in the above-described embodiment, the content of the inner ring or the outer ring of the planetary gear bearing being configured so that the rigidity in the radial direction is low is illustrated, but the present invention is not limited thereto, and both the inner ring and the outer ring are in the radial direction. It is also possible to configure so as to reduce the rigidity.

  In addition, the internal gear, the sun gear, the carrier, the planetary gear, the support shaft, the planetary gear bearing, the inner ring, the outer ring, the inner peripheral surface of the inner ring, the groove, the outer peripheral surface of the outer ring, the spring material, and the rubber exemplified in the above-described embodiments. The material, shape, size, form, number, location, etc. of the material and synthetic resin material are arbitrary and are not limited as long as the present invention can be achieved.

FIG. 1A is a schematic view of a planetary gear device provided with a planetary gear bearing according to the present invention, and FIG. 1B is a front view of the planetary gear device. It is sectional drawing which shows 1st Embodiment of the planetary gear bearing which concerns on this invention. It is sectional drawing which shows 2nd Embodiment of the planetary gear bearing which concerns on this invention. It is sectional drawing which shows 3rd Embodiment of the planetary gear bearing which concerns on this invention. It is sectional drawing which shows 4th Embodiment of the planetary gear bearing which concerns on this invention. It is sectional drawing which shows 5th Embodiment of the planetary gear bearing which concerns on this invention. It is sectional drawing which shows 6th Embodiment of the planetary gear bearing which concerns on this invention. It is sectional drawing which shows 7th Embodiment of the planetary gear bearing which concerns on this invention. It is sectional drawing which shows 8th Embodiment of the planetary gear bearing which concerns on this invention. It is the schematic which shows the conventional planetary gear apparatus. It is a front view which shows the conventional planetary gear apparatus. It is a front view which shows the effect | action of the conventional planetary gear apparatus. It is a front view which shows another effect | action of the conventional planetary gear apparatus. It is a principal part enlarged view which shows the effect | action of the conventional planetary gear apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bearing for planetary gears 11 Internal gear 12 Sun gear 13 Carrier 15 Planetary gear 15A Planetary gear 15A Inner peripheral surface 16 Support shaft 16C Outer peripheral surface of support shaft 20, 30, 35, 40, 45, 50, 55, 60 Planetary gear Bearings 25, 31, 36, 44, 46, 51, 56 Inner rings 26, 28, 41, 62 Outer rings 29, 32, 37, 47, 52, 57 Inner ring inner peripheral surfaces 29A, 32A, 37A, 3842A, 47A, 52A, 57A, 63A Groove 42, 63 Outer ring outer peripheral surface 48 Spring material (elastic body)
53, 58, 64 Rubber material or synthetic resin material (elastic body)

Claims (3)

A sun gear is provided in the center of the ring-shaped internal gear, and a plurality of planetary gears are arranged via a carrier between the internal gear and the sun gear, and the plurality of planetary gears mesh with the internal gear and the sun gear. In the planetary gear, the planetary gear bearing interposed between the support shaft provided in the carrier and the planetary gear,
A planetary gear bearing comprising an inner ring fitted to the support shaft and an outer ring fitted to the planetary gear, wherein at least one of the inner and outer rings is configured to have low radial rigidity.   2. A circumferential groove portion is provided on an inner peripheral surface of the inner ring and an outer peripheral surface of the outer ring so that a thickness of at least one of the inner ring and the outer ring becomes thin at an axial center. The planetary gear bearing described.   An elastic body is provided in the groove, and the elastic body is applied to the outer peripheral surface of the support shaft to which the planetary gear bearing is fitted or the inner peripheral surface of the planetary gear to which the planetary gear bearing is fitted. The planetary gear bearing according to claim 2, wherein the planetary gear bearing is in contact with the planetary gear.

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