JP2010255645A - Radial needle bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radial needle bearing incorporated into the planetary gear mechanism of a vehicular automatic transmission capable of maintaining the strength of columns while reducing wear. <P>SOLUTION: The radial needle bearing 20 is arranged between a supporting shaft 4e and a planetary gear 4c of the planetary gear mechanism 4 of the vehicular automatic transmission. The bearing includes: a cage 10 including a pair of rims 11 provided at both axial ends and the plurality of columns 12 provided intermittently in the peripheral direction in a state of being bridged between both the rims, and having pockets 13 in areas where its four sides are encircled by the peripherally adjacent columns 11, 11 and both the rims 12, 12; a plurality of needles 16 rollingly held in the pockets 13; and a guide member 17 for guiding the cage 10. The rims 11 of the cage 10 have tapered faces 21 guided by the guide member 17. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radial needle bearing.

  Conventionally, a radial needle bearing is incorporated in a portion to which a large radial load is applied in an automobile transmission. For example, in Patent Documents 1 and 2, in a planetary gear mechanism that constitutes an automatic transmission of an automobile, the planetary gear is rotatably supported with respect to the support shaft of the carrier.

  This automobile transmission is required to have low friction and high rotation in order to improve fuel efficiency and to cope with a hybrid vehicle. For this reason, the radial needle bearing used for the planetary gear mechanism that constitutes the automobile transmission has a demand for lower torque and higher rotation.

  Here, in the planetary gear mechanism, the planetary gear revolves around the sun gear while rotating, but at this time, the radial needle bearing supporting the planetary gear also rotates and revolves around the sun gear. Centrifugal force due to revolution is applied to the radial needle bearing. Therefore, the stress generated in the cage is large and the strength is required. In addition, since the cage is pressed against the inner peripheral surface of the planetary gear by centrifugal force based on revolution, sliding occurs between the inner peripheral surface of the planetary gear and the cage, and friction, wear, and heat generation on the outer peripheral surface are caused. The problem is damage and increased torque.

  Patent Document 1 discloses that an oil groove is formed on the outer peripheral surface of an M-type cage used for outer diameter guide, thereby improving the lubricity of the radial needle bearing and suppressing the occurrence of wear.

  Patent Document 2 discloses that the cage is used as an inverted M-shape and is used for inner diameter guidance, and an oil groove is provided on the inner circumferential surface of the cage to improve the lubricity of the inner circumferential surface while reducing the sliding speed. ing.

  On the other hand, in Patent Document 3, as a radial needle bearing used in a planetary gear speed reduction device that constitutes a crawler belt drive device such as a construction machine, a protrusion having a diameter substantially the same as that of a rim portion is provided on a column portion, and a rattling during rotation is provided. In addition to preventing sticking, it is disclosed that an oil groove is formed on the outer peripheral surface of the rim portion to improve lubricity.

JP 2004-324844 A JP 2007-255494 A JP 2001-304270 A

  However, in the radial needle bearing of Patent Document 1, since the cage is used for the outer diameter guide, the sliding speed is large and there is room for improvement in torque reduction.

  Further, in the radial needle bearing described in Patent Document 2, since a large number of oil grooves are formed on the inner peripheral surface of the cage including the column portion, there is a concern that the strength of the cage is reduced. In addition to the stress due to sliding and contact, the pillar portion of the cage, particularly the connecting portion with the rim portion, is subjected to a load due to the pressing of the needle and centrifugal force, and a high stress is generated. Therefore, if there is an oil groove in the vicinity of the connecting portion, it may become a stress concentration source and lead to breakage.

  In addition, the radial needle bearing described in Patent Document 3 is not originally used in a planetary gear mechanism that constitutes an automatic transmission of an automobile, and it is quiet by preventing rattling of the cage against a large torque. This is to improve the durability, and the thickness of the pillar portion and the rim portion of the cage is large, and this cannot be applied to an automatic transmission of an automobile as it is.

  The present invention has been made to eliminate such inconveniences, and an object of the present invention is, in particular, a planetary gear mechanism of an automatic transmission for a vehicle capable of maintaining the strength of a column while reducing friction. It is an object to provide a radial needle bearing suitable for the above.

The above object of the present invention can be achieved by the following constitution.
(1) In a radial needle bearing disposed between a pinion shaft and a pinion gear in a planetary gear mechanism of a vehicle automatic transmission,
A pair of rim portions provided at both ends in the axial direction, and a plurality of pillar portions intermittently provided in the circumferential direction in a state of being spanned between the two rim portions; A cage having a pocket surrounded by four sides by the adjacent column part and the two rim parts;
A plurality of needles that are rotatably held in the pockets;
A guide member for guiding the cage,
The radial needle bearing according to claim 1, wherein the rim portion of the cage has a tapered surface guided by the guide member.
(2) The pinion shaft is supported by support plates provided at both ends in the axial direction,
The radial needle bearing according to (1), wherein the guide member is formed integrally with a washer interposed between an axial end surface of the pinion gear and an inner surface of the support plate.
(3) The needles are arranged in double rows,
The needles in each row are held so as to be freely rollable by the cages provided in the rows,
A spacer is provided between the adjacent cages,
The radial needle bearing according to (1), wherein the guide member is formed integrally with the spacer.
(4) The radial needle bearing according to any one of (1) to (3), wherein the guide member has a tapered surface corresponding to a tapered surface of the rim portion.
(5) If the distance between the outermost diameter part of the cage and the inner peripheral surface of the pinion gear is δo, and the distance between the innermost diameter part of the cage and the outer peripheral surface of the pinion shaft is δi, it relates to the rotation and eccentricity of the pinion gear. The radial needle bearing according to any one of (1) to (4), wherein δo> 0 and δi> 0 are satisfied.

  According to the radial needle bearing of the present invention, the cage is rotationally guided in both radial and axial directions by the tapered surfaces formed at the rim portions at both ends of the cage, so that the contact between the cage outer peripheral surface and the pinion gear inner peripheral surface is prevented. It is avoiding. Thereby, the damage by the friction and abrasion of the outer peripheral surface of the cage and the strength reduction can be suppressed. In addition, the relative sliding speed is smaller than that of the outer diameter guide on the outer peripheral surface of the cage, and wear reduction and torque reduction can be achieved.

  Further, since the guide member is formed integrally with the washer or the spacer, the manufacturing cost can be reduced more inexpensively.

  Further, since the guide member has a tapered surface corresponding to the tapered surface of the rim portion, the surface pressure can be reduced and the durability can be improved.

  Further, if the distance between the outermost diameter portion of the cage and the inner peripheral surface of the pinion gear is δo and the distance between the innermost diameter portion of the cage and the outer peripheral surface of the pinion shaft is δi, regardless of the rotation or eccentricity of the pinion gear, δo> By satisfying 0 and δi> 0, the cage can be prevented from coming into contact with the inner peripheral surface of the pinion gear or the outer peripheral surface of the pinion shaft and being damaged.

It is an exploded view of the planetary gear mechanism in which the radial needle bearing of the present invention is incorporated. It is sectional drawing of 1st Embodiment of the radial needle bearing of this invention. It is a washer incorporated in the radial needle bearing of Drawing 2, (a) is a perspective view of a washer, and (b) is a sectional view of a washer. It is sectional drawing of the 1st modification of the radial needle bearing of FIG. FIG. 5 is a perspective view of a washer incorporated in the radial needle bearing of FIG. 4. It is a fragmentary sectional view of the 2nd modification of the radial needle bearing of FIG. It is a fragmentary sectional view of the 3rd modification of the radial needle bearing of FIG. It is a fragmentary sectional view of the holder | retainer of the 4th modification of the radial needle bearing of FIG. It is a fragmentary sectional view of the 5th modification of the radial needle bearing of FIG. It is sectional drawing of 2nd Embodiment of the radial needle bearing of this invention. It is sectional drawing of 3rd Embodiment of the radial needle bearing of this invention.

Embodiments of a radial needle bearing according to the present invention will be described below with reference to the drawings.
<First Embodiment>
A radial needle bearing 20 of this embodiment is incorporated in a planetary gear mechanism constituting an automatic transmission of an automobile and used for oil lubrication. FIG. 1 shows a planetary gear mechanism in which a radial needle bearing of the present invention is incorporated. FIG.

  As shown in FIG. 1, the planetary gear mechanism 4 includes a ring gear 4a having internal teeth, a sun gear 4b having external teeth, three planetary gears (pinion gears) 4c meshing with the ring gear 4a and the sun gear 4b, and a support. The planetary gear 4c is rotatably supported by three pinion shafts 4e as shafts, and has a carrier 4d that can also rotate itself.

  As shown in FIG. 2, the radial needle bearing 20 includes a plurality of needles 16, 16 arranged at a predetermined interval in the circumferential direction, a holder 10 that holds the needles 16, 16 in a rollable manner, and a holder 10. And a guide member 17 that guides the cage.

  The retainer 10 is a so-called M-shaped retainer, and is arranged with a pair of rim portions 11 and 11 each having an annular shape (cylindrical shape or annular shape) and spaced apart from each other in the axial direction. Column parts 12, 12. These column parts 12 and 12 are intermittently arranged in the circumferential direction, and both end parts thereof are connected to outer diameter end parts of the inner side surfaces of the rim parts 11 and 11 facing each other. . Moreover, each said pillar part 12 and 12 has the shape where the axial direction intermediate part bent in the trapezoid shape toward radial inside. And the space part enclosed by four sides by the circumferential direction both sides edge of these each pillar parts 12 and 12 adjacent to the circumferential direction, and the mutually opposing inner surface of both said rim parts 11 and 11, respectively, each needle 16, Pockets 13 and 13 are provided for holding 16 in a rollable manner.

  The radial needle bearing 20 has the pinion shaft outer peripheral surface 4e1 of the pinion shaft 4e as an inner ring raceway, and the planetary gear inner peripheral surface (pinion gear inner peripheral surface) 4c1 of the planetary gear 4c as an outer ring raceway. The 16 rolling surfaces are in rolling contact with the inner ring raceway and the outer ring raceway. In addition, floating washers 9 and 9 are disposed between both axial end surfaces of the planetary gear 4c and the inner side surfaces of both support plates 4f and 4f provided on the end of the pinion shaft 4e and constituting the carrier 4d, respectively. Thus, the frictional force acting between the axial end surfaces of the planetary gear 4 and the inner side surfaces of the support plates 4f and 4f is reduced.

  Here, the cage 10 of the present embodiment is configured to have a tapered surface 21 in which the rim portions 11, 11 are formed in a substantially linear shape extending outward in the axial direction while inclining radially inward.

  The floating washer 9 is manufactured by press-molding a thin metal plate, and as shown in FIG. 3, a protruding portion 91 protruding inward in the axial direction is provided between the outer diameter side end portion and the inner diameter side end portion. The projecting portion 91 has an outer peripheral surface 92 that is substantially perpendicular to the inner end surface of the floating washer 9 and is always positioned on the outer diameter side of the outer peripheral surface of the column portion. The taper surface 93 is formed so as to correspond to a substantially straight line. That is, in this embodiment, the guide member 17 is formed integrally with the floating washer 9.

  The planetary gear 4c revolves around the sun gear 4b while rotating, and at this time, the radial needle bearing 20 supporting the planetary gear 4c also rotates and revolves around the sun gear 4b, and the cage 10 Is pressed against the floating washer 9 by the centrifugal force based on the revolution, so that sliding occurs between the tapered surface 93 of the floating washer 9 and the tapered surface 21 of the rim portion 11. The taper surface 93 is rotated and guided in both radial and axial directions.

  At this time, the distance between the outer peripheral surface of the pillar portion, which is the outermost diameter portion of the cage 10, and the inner peripheral surface 4c1 of the planetary gear is δo (see FIG. 2), and the tip end portion of the tapered surface, which is the innermost diameter portion of the cage 10, and the pinion Assuming that the distance from the shaft outer peripheral surface 4e1 is δi (see FIG. 2), it is set to satisfy δo> 0 and δi> 0 regardless of the rotation and eccentricity of the planetary gear 4c. In the present embodiment, the innermost diameter portion of the cage 10 is the rim tip portion, but the innermost diameter portion may be the inner peripheral surface of the column portion.

  As described above, according to the radial needle bearing 20 of the present embodiment, the retainer 10 is rotatably guided in both the radial and axial directions by the tapered surfaces 21 formed on the rim portions 11 at both ends of the retainer. The contact between the outer peripheral surface of the vessel and the inner peripheral surface 4c1 of the planetary gear is avoided. Thereby, the damage by the friction and abrasion of the outer peripheral surface of the cage and the strength reduction can be suppressed. In addition, the relative sliding speed is smaller than that of the outer diameter guide on the outer peripheral surface of the cage, and wear reduction and torque reduction can be achieved.

  Further, since the guide member 17 is formed integrally with the floating washer 9, the manufacturing cost can be reduced more inexpensively.

  Further, since the floating washer 9 as the guide member 17 has the tapered surface 93 corresponding to the tapered surface 21 of the rim portion 11, the surface pressure can be reduced and the durability can be improved.

  Further, assuming that the distance between the outermost diameter portion of the cage 10 and the planetary gear inner peripheral surface 4c1 is δo and the distance between the innermost diameter portion of the cage and the pinion shaft outer peripheral surface 4e1 is δi, the rotation and eccentricity of the planetary gear 4c. Regardless, by satisfying δo> 0 and δi> 0, the cage 10 can be prevented from coming into contact with the planetary gear inner peripheral surface 4c1 or the pinion shaft outer peripheral surface 4e1 and being damaged.

  Next, a modification of this embodiment will be described. In addition, the same code | symbol or an equivalent code | symbol is attached | subjected to the same or equivalent part as 1st Embodiment, and description is simplified or abbreviate | omitted.

FIG. 4 is a partial cross-sectional view of a radial needle bearing according to a first modification of the present embodiment, and FIG. 5 is a perspective view of a floating washer incorporated in the radial needle bearing of FIG.
In this modification, a plurality of oil grooves 95 are linearly provided at predetermined intervals in the circumferential direction on the outer peripheral surface 92 and the tapered surface 93 of the protrusion 91 provided on the floating washer 9.
As a result, as indicated by the arrows in the figure, the lubricating oil supplied from the oil hole 4e2 of the pinion shaft 4e to the bearing space is supplied to the gear end via the oil groove 95, and the lubricating oil stays in the bearing space. An increase in stirring resistance can be suppressed. Moreover, since sufficient lubricating oil can be spread over the contact surface and the sliding surface, it is possible to reduce the wear and friction of the contact portion and the torque.
In this modification, the oil groove 95 is provided on both the outer peripheral surface 92 and the tapered surface 93 of the protruding portion 91, but the oil groove 95 is provided on at least one of the outer peripheral surface 92 and the tapered surface 93 of the protruding portion 91. The oil groove 95 may be linear or curved, and may be formed so as to be inclined with respect to the central axis of the pinion shaft 4e to promote oil discharge by rotation.

FIG. 6 is a partial sectional view of a radial needle bearing according to a second modification of the present embodiment.
In this modified example, the floating washer 9A is formed in a substantially disc shape, and the guide member 17 having the tapered surface 93 corresponding to the tapered surface 21 of the rim portion 11 is provided between the inner end surface of the floating washer 9A and the planetary gear. It is disposed in an annular space formed by the peripheral surface 4 c 1 and the tapered surface 21 of the rim portion 11.
Thereby, since the guide member 17 for rotating and guiding the cage 10 can be rotated independently, the sliding speed of the cage 10 and the guide member 17 may be further reduced. A general purpose floating washer can be used as the floating washer 9A.
The shape of the guide member 17 is not limited to this, and it is only necessary to have a tapered surface 93 corresponding to the tapered surface 21 of the rim portion 11.

FIG. 7 is a partial sectional view of a radial needle bearing according to a third modification of the present embodiment.
In this modification, the tapered surface 21 of the rim portion 11 is formed in a crowning shape. As a result, even when the cage 10 is eccentric with respect to the pinion shaft 4e and the rotation axis of the cage 10 is inclined with respect to the pinion shaft 4e, contact with the tapered surface 21 is ensured and the edge of the rim portion 11 is secured. Thus, damage to the guide member 17 and the like can be suppressed.
In the present modification, the tapered surface 21 of the rim portion 11 has a crowning shape. However, the present invention is not limited to this. Or an arcuate convex curved surface having a relatively large diameter. Further, one of the tapered surface 93 of the guide member 17 and the tapered surface 21 of the rim portion 11 may be a convex curved surface having a relatively large diameter, and the other may be a concave curved surface.

FIG. 8 is a partial cross-sectional view of a cage used in a radial needle bearing of a fourth modification of the present embodiment.
In this modification, the rim portion 11 of the cage 10 is subjected to surface treatment such as heat treatment, shot peening, a resin coating, a fixed lubricating film, and a hard film to improve lubricity and wear resistance. In addition, you may perform the surface treatment mentioned above not only on the rim | limb part 11, but the holder | retainer 10 whole.

FIG. 9 is a partial cross-sectional view of a radial needle bearing of a fifth modification of the present embodiment.
In this modification, heat treatment, shot peening, a resin coating, a vicinity of the end of the planetary gear inner peripheral surface 4c1 of the planetary gear 4c facing the outer peripheral surface 92 of the guide member 17, that is, a region surrounded by an ellipse in FIG. Surface treatment such as fixed lubricating film and hard film is applied to improve lubricity and wear resistance.
Thereby, even when the pressing force of the cage 10 is applied to the planetary gear inner peripheral surface 4c1 via the guide member 17 by centrifugal force, the lubricity and wear resistance can be improved.

Next, a radial needle bearing according to a second embodiment of the present invention will be described.
<Second Embodiment>
FIG. 10 is a cross-sectional view of a second embodiment of the radial needle bearing of the present invention. In addition, the same code | symbol or an equivalent code | symbol is attached | subjected to the same or equivalent part as 1st Embodiment, and description is simplified or abbreviate | omitted.
The radial needle bearing 20A of the present embodiment is a double row radial needle bearing in which needles are arranged in a double row, and the needles 16 and 16 in each row are rollable to the cages 10 and 10 provided in the respective rows. A spacer 18 is provided between the cages 10 and 10 which are held and adjacent to each other.

  The spacer 18 is a metallic cylindrical member whose inner peripheral surface slides on the pinion shaft outer peripheral surface 4e1 and whose outer peripheral surface slides on the planetary gear inner peripheral surface 4c1, and protrudes to both sides in the axial direction at the outer diameter side edge. Projecting portions 35, 35 are provided, and the projecting portion 35 is formed in a substantially straight shape so that the inner peripheral surface thereof corresponds to the tapered surface 21 formed on the rim portion 11, and forms a tapered surface 36 that acts as a guide surface. ing. That is, in this embodiment, the guide member 17 is also formed integrally with the spacer 18.

  The planetary gear 4c revolves around the sun gear 4b while rotating, but at this time, the radial needle bearing 20A supporting the planetary gear 4c also rotates and revolves around the sun gear 4b, and the cage 10 10 is pressed against the floating washer 9 and the spacer 18 by the centrifugal force based on the revolution, and therefore, the sliding surface between the tapered surface 93 of the floating washer 9 and the tapered surface 36 of the spacer 18 and the tapered surface 21 of the rim portion 11 is slid. As a result, the cage 10 is rotatably guided in both radial and axial directions by the tapered surface 93 of the floating washer 9 and the tapered surface 36 of the spacer 18.

  In the radial needle bearing 20A of the present embodiment configured in a double row in this way as well as the radial needle bearing 20 of the first embodiment, the taper surfaces 21 formed on the rim portions 11 at both ends of the cage are used for the radial needle bearing 20A. Since it is rotated and guided in both axial directions, damage and strength reduction due to friction and wear on the outer peripheral surface of the cage can be suppressed. In addition, the relative sliding speed is smaller than that of the outer diameter guide on the outer peripheral surface of the cage, and wear reduction and torque reduction can be achieved.

  Further, since the guide member 17 is formed integrally with the floating washer 9 and the spacer 18, the manufacturing cost can be suppressed at a lower cost, and the washer 9 and the spacer 18 are tapered surfaces corresponding to the tapered surface 21 of the rim portion 11. By having 93 and 36, the surface pressure can be reduced and the durability can be improved.

Next, a radial needle bearing according to a third embodiment of the present invention will be described.
<Third Embodiment>
FIG. 11 is a cross-sectional view of a third embodiment of the radial needle bearing of the present invention.

  As shown in FIG. 11, the radial needle bearing 20 </ b> B includes a plurality of needles 56, 56 arranged at predetermined intervals in the circumferential direction, a holder 50 that holds the needles 56, 56 in a rollable manner, and a holder 50. And a guide member 17 that guides the cage.

  The cage 50 includes a pair of rim portions 51 and 51 each having an annular shape (cylindrical shape or annular shape) and a plurality of column portions 52 and 52 which are arranged at intervals in the axial direction. . These column portions 52 and 52 are intermittently arranged in the circumferential direction, and both end portions thereof are connected to inner diameter end portions of the inner side surfaces of the rim portions 51 and 51 facing each other. Each of the column parts 52, 52 has a shape in which an axially intermediate part is bent in a trapezoidal shape outward in the radial direction. And the space part surrounded by four sides by the circumferential direction both sides edge of each of these pillar parts 52 and 52 adjacent to the circumference direction and the inner side surface which said rim parts 51 and 51 mutually oppose is each needle 56, respectively. Pockets 53 and 53 are provided for holding 56 in a freely rotatable manner.

  Here, the cage 50 of the present embodiment has a tapered surface 61 that is formed in a substantially linear shape with the rim portions 51, 51 extending radially outward while being inclined radially outward, and the tapered surface 61 is a guide member. 17 is opposed to the guide surface of the floating washer 9B.

  The washer 9B is manufactured by press-molding a thin metal plate, and is provided with a protruding portion 96 protruding inward in the axial direction at the inner diameter side end portion, and the inner peripheral surface 97 of the protruding portion 96 is substantially orthogonal to the outer end surface. The outer peripheral surface is formed in a substantially linear shape so as to correspond to the tapered surface 61 formed on the rim portion 11, and forms a tapered surface 98 that functions as a guide surface.

  The planetary gear 4c revolves around the sun gear 4b while rotating. At this time, the radial needle bearing 20B supporting the planetary gear 4c also rotates and revolves around the sun gear 4b together with the floating washer 9B. Since the floating washer 9B is pressed against the retainer 50 by the centrifugal force based on the revolution, sliding occurs between the tapered surface 98 of the floating washer 9B and the tapered surface 61 of the rim portion 51. It is rotationally guided in both radial and axial directions by the tapered surface 98 of the floating washer 9B.

  At this time, the distance between the rim tip portion that is the outermost diameter portion of the cage 50 and the planetary gear inner circumferential surface 4c1 is δo, and the inner circumferential surface of the column portion that is the innermost diameter portion of the cage 50 and the outer peripheral surface 4e1 of the pinion shaft. When the interval is δi, δo> 0 and δi> 0 are set regardless of the rotation and eccentricity of the planetary gear 4c. In the present embodiment, the outermost diameter portion is the tip portion of the rim portion, but the outermost diameter portion may be the outer peripheral surface of the column portion.

  As described above, according to the radial needle bearing 20B of the present embodiment, since the rotation is guided in both radial and axial directions by the tapered surfaces 61 formed on the rim portions 51 at both ends of the cage, the outer circumferential surface of the cage and the planet Contact with the gear inner peripheral surface 4e1 is avoided. Thereby, the damage by the friction and abrasion of the outer peripheral surface of the cage and the strength reduction can be suppressed.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. Although the said 1st-5th modification was described as a modification of 1st Embodiment of the radial needle bearing 20, not only this but the radial needle bearing 20A, 20B of 2nd and 3rd embodiment is corrected suitably. Can be applied.

4 Planetary gear mechanism 4e Support shaft (pinion shaft)
4c Planetary gear (pinion gear)
4c1 Planetary gear inner peripheral surface (pinion gear inner peripheral surface)
4f Support plate 9, 9B Floating washer (guide member)
9A Floating washer 10, 50 Cage 11, 51 Rim part 21, 61 Tapered surface 12, 52 Pillar part 13, 53 Pocket 16, 56 Needle 17 Guide member 18 Spacer (guide member)
36, 93, 98 Tapered surface 20, 20A, 20B Radial needle bearing

Claims (5)

In a radial needle bearing disposed between a pinion shaft and a pinion gear in a planetary gear mechanism of a vehicle automatic transmission,
A pair of rim portions provided at both ends in the axial direction, and a plurality of pillar portions intermittently provided in the circumferential direction in a state of being spanned between the two rim portions; A cage having a pocket surrounded by four sides by the adjacent column part and the two rim parts;
A plurality of needles that are rotatably held in the pockets;
A guide member for guiding the cage,
The radial needle bearing according to claim 1, wherein the rim portion of the cage has a tapered surface guided by the guide member. The pinion shaft is supported by support plates provided at both axial ends,
The radial needle bearing according to claim 1, wherein the guide member is integrally formed with a washer interposed between an axial end surface of the pinion gear and an inner surface of the support plate. The needles are arranged in double rows,
The needles in each row are held so as to be freely rollable by the cages provided in the rows,
A spacer is provided between the adjacent cages,
The radial needle bearing according to claim 1, wherein the guide member is formed integrally with the spacer.   The radial needle bearing according to claim 1, wherein the guide member has a tapered surface corresponding to a tapered surface of the rim portion.   If the distance between the outermost diameter part of the cage and the inner peripheral surface of the pinion gear is δo and the distance between the innermost diameter part of the cage and the outer peripheral surface of the pinion shaft is δi, δo regardless of the rotation or eccentricity of the pinion gear. The radial needle bearing according to claim 1, wherein> 0 and δi> 0 are satisfied.

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