JP2010255778A - Radial needle bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radial needle bearing capable of reducing friction, and capable of realizing high rotation. <P>SOLUTION: This radial needle bearing 20 is arranged between a support shaft 4e and a planetary gear 4c in the planetary gear mechanism 4 of an automatic transmission for a vehicle, and includes a cage 10 for rollingly holding a plurality of needles 16 arranged at a predetermined interval in the peripheral direction and used for guiding an outer diameter, and a floating bush 17 arranged between the cage 10 and the planetary gear 4c and relatively rotatable to the cage outer peripheral surface 15 and a planetary gear inner peripheral surface 4c1. <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 Document 1, in a planetary gear mechanism that constitutes an automatic transmission for 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, since the cage of the radial needle bearing is pressed against the inner peripheral surface of the planetary gear by the centrifugal force based on the revolution, the sliding occurs between the inner peripheral surface of the planetary gear and the retainer. Such sliding increases the drag resistance of the radial needle bearing.

  In the radial needle bearing described in Patent Document 1, grinding and / or surface treatment is applied to the outer peripheral surface of the cage, which is a guide surface, in order to reduce torque.

JP 2005-76810 A

  However, in the radial needle bearing described in Patent Document 1, grinding and / or surface treatment has a problem that the friction reduction effect gradually decreases as the surface accuracy is improved, and the cost for processing increases. was there.

  The present invention has been made in order to eliminate such inconveniences, and an object of the present invention is to provide a radial needle bearing capable of reducing friction and increasing the rotation speed.

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 plurality of needles arranged at predetermined intervals in the circumferential direction;
A cage that holds the needle in a rollable manner and is used in an outer diameter guide;
A radial needle bearing comprising: a floating bush disposed between the retainer and the pinion gear and capable of rotating relative to the retainer outer peripheral surface and the pinion gear inner peripheral surface.
(2) The pinion shaft is supported by a support plate provided at an axial end,
A washer is provided between the outer end surface of the pinion gear and the inner end surface of the support plate,
The radial needle bearing according to (1), wherein the floating bush is formed integrally with the washer.
(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) or (2), wherein the floating bush is formed integrally with the spacer.

  According to the radial needle bearing of the present invention, since the floating bush arranged between the cage and the pinion gear rotates relative to the cage outer peripheral surface and the pinion gear inner peripheral surface, the sliding speed is reduced, thereby causing the slip. Friction is reduced. In addition, since the sliding speed is reduced, seizure hardly occurs, and thereby high rotation can be achieved. Furthermore, since the floating bush can be manufactured by pressing, the manufacturing cost can be reduced at a low cost.

  In addition, the floating bush is formed integrally with the washer or the spacer, so that the manufacturing cost can be reduced more inexpensively.

It is a disassembled perspective 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 side view of a radial needle bearing provided with a split type floating bush. It is sectional drawing of 2nd Embodiment of the radial needle bearing of this invention. It is a fragmentary sectional view showing the 1st modification of a radial needle bearing of a 2nd embodiment of the present invention. It is a fragmentary sectional view showing the 2nd modification of a radial needle bearing of a 2nd embodiment of the present invention. It is a fragmentary sectional view showing the 3rd modification of a radial needle bearing of a 2nd embodiment of the present 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. The planetary gear 4c is not limited to three.

  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, and a cage used for outer diameter guidance by holding the needles 16, 16 so as to roll. 10 and a cage and roller configured to include floating bushes 17 and 17 disposed on the outer diameter side of the cage 10.

  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. Further, floating washers 9 and 9 are respectively disposed between both end surfaces of the planetary gear 4c in the axial direction and inner side surfaces of both support plates 4f and 4f which are provided at the end of the pinion shaft 4e and constitute the carrier 4d. Thus, the frictional force acting between both axial end surfaces of the planetary gear 4c and the inner side surfaces of the support plates 4f and 4f is reduced.

  The floating bush 17 is a metal member formed in an annular shape, and is a cylindrical space formed between the rim portion 11 of the retainer 10 and the planetary gear 4 c, and in the vicinity of both end faces of the needle 16. Here, it is disposed between the end surface of the needle 16 and the floating washer 9, and is configured to be rotatable relative to the outer peripheral surface of the rim which is the outer peripheral surface 15 of the cage and the inner peripheral surface 4c1 of the planetary gear.

  The planetary gear 4c revolves around the sun gear 4b while rotating, and at this time, the radial needle bearing 20 that supports the planetary gear 4c also rotates and revolves around the sun gear 4b. The centrifugal force due to is applied to the radial needle bearing 20. Therefore, since the cage 10 is pressed against the planetary gear inner circumferential surface 4c1 by the centrifugal force based on the revolution, sliding occurs between the cage outer circumferential surface 15 and the planetary gear inner circumferential surface 4c1.

  Here, according to the radial needle bearing 20 of the present embodiment, the floating bush 17 disposed between the cage 10 and the planetary gear 4c rotates relative to the cage outer peripheral surface 15 and the planetary gear inner peripheral surface 4c1. As a result, the sliding speed is reduced, thereby reducing the sliding friction. In addition, since the sliding speed is reduced, seizure hardly occurs, and thereby high rotation can be achieved. Further, since the floating bush 17 can be manufactured by press working, the manufacturing cost can be reduced at a low cost.

  In the present embodiment, an annular floating bush formed continuously in the circumferential direction is illustrated as the floating bush 17; however, the present invention is not limited to this, and as shown in FIG. It is good also as a division | segmentation type floating bush arrange | positioned by predetermined spacing. Thereby, seizure prevention and swinging of the pinion shaft 4e can be prevented.

<Second Embodiment>
FIG. 4 is a cross-sectional view of a second embodiment of the radial needle bearing of the present invention. In FIG. 4, the same or equivalent parts as those in the first embodiment are denoted by the same or corresponding reference numerals, and description thereof is simplified or 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 formed in a substantially inverted U shape so that an inner diameter side of a thin metal plate is opened, and is disposed so as to be relatively rotatable with respect to the adjacent cages 10 and 10. The outer peripheral surface of the spacer 18 may slide with the planetary gear inner peripheral surface 4c1, or may be arranged to face the planetary gear inner peripheral surface 4c1 through a predetermined gap so as not to slide. The spacer 18 is manufactured by various processing methods such as press molding, and the shape of the spacer 18 may be other shapes as long as it functions as a spacer.

  The floating bush 17 is a cylindrical space formed between the rim parts 11 and 11 of the cages 10 and 10 and the planetary gear 4c, in the vicinity of both end faces of the needles 16 and 16, here the needles. 16 and 16 are disposed between the end face of the floating washer 9 and between the end face of the needles 16 and 16 and the spacer 18.

  In the radial needle bearing 20A of the present embodiment configured in a double row as described above, the floating bush 17 is provided on the outer peripheral surface 15 of the cage and the inner peripheral surface 4c1 of the planetary gear, similarly to the radial needle bearing 20 of the first embodiment. Since it rotates relative to the sliding speed, the sliding speed decreases, thereby reducing sliding friction. In addition, since the sliding speed is reduced, seizure hardly occurs, and thereby high rotation can be achieved.

Hereinafter, modified examples of the present embodiment will be described with reference to FIGS. 5 to 7 show only one (left side) row of the double row radial needle bearings, and the same or equivalent parts as those of the second embodiment are denoted by the same or corresponding symbols. Simplify or omit.
FIG. 5 is a partial cross-sectional view of a first modification of the radial needle bearing of the second embodiment.
The radial needle bearing 20B of the present embodiment is configured such that two floating bushes 17 are laminated in the radial direction in the vicinity of both end faces of the needle 16, and slip occurs between the two laminated floating bushes 17A and 17B. Has been.

  Further, a notch 19 is provided on the outer peripheral surface of the rim of the cage 10, and the floating bush 17 </ b> B located on the radially inner side is sandwiched between the floating washer 9 and the notch 19 and is positioned in the axial direction. The notch 19 is mainly for securing a clearance between the outer peripheral surface 15 of the cage and the inner peripheral surface 4c1 of the planetary gear, and is not necessary if there is a sufficient clearance. Not limited to this, it may be provided on the planetary gear inner peripheral surface 4 c 1, or may be provided on both the planetary gear inner peripheral surface 4 c 1 and the cage outer peripheral surface 15.

  According to the radial needle bearing 20B of the present embodiment configured as described above, a further reduction in the sliding speed is expected, and seizure hardly occurs, whereby high rotation can be achieved. In this modification, two floating bushes 17A and 17B are stacked. However, the present invention is not limited to this, and three or more floating bushes may be stacked if there is a gap.

FIG. 6 is a partial cross-sectional view of a second modification of the radial needle bearing of the second embodiment.
In the radial needle bearing 20C of the present embodiment, the washer 9 is formed integrally with the floating bush 17 to form the washer 9A with the floating bush, and the spacer 18 is also formed integrally with the floating bush 17 to form the spacer 18A with the floating bush. ing.

  The washer 9A with a floating bush is configured by press molding so that a substantially middle portion of a thin metal plate is bent inward in the axial direction, and the bent portion 91 is disposed between the cage 10 and the planetary gear 4c. The cage rotates relative to the outer peripheral surface 15 of the cage and the inner peripheral surface 4c1 of the planetary gear and functions as a floating bush. Further, a notch 4c2 is provided at the outer end of the planetary gear inner peripheral surface 4c1, and a bent portion 91 is partially accommodated in the notch 4c2.

  The notch 4c2 is mainly for securing a clearance between the outer peripheral surface 15 of the cage and the inner peripheral surface 4c1 of the planetary gear, and it is not necessary to provide a sufficient clearance, and the inner peripheral surface of the planetary gear. It is not limited to 4c1 and may be provided on the outer peripheral surface 15 of the cage, or may be provided on both the inner peripheral surface 4c1 of the planetary gear and the outer peripheral surface 15 of the cage.

  The spacer 18A with a floating bush is configured by press-molding a thin metal plate into a substantially U shape so that the outer diameter side opens, and further extends outward in the axial direction from the outer diameter end. An extending portion 81 is provided. The extending portion 81 is disposed between the cage 10 and the planetary gear 4c, rotates relative to the cage outer peripheral surface 15 and the planetary gear inner peripheral surface 4c1, and functions as a floating bush.

According to the radial needle bearing 20C of the present embodiment configured as described above, the floating bush can be manufactured integrally with the washer and the spacer, so that the manufacturing cost can be reduced and the number of parts can be reduced. be able to.
In this modification, the washer and the spacer are the washer 9A with the floating bush and the spacer 18A with the floating bush, respectively, but only one of the washer and the spacer may be integrated with the floating bush.

FIG. 7 is a partial cross-sectional view of a third modification of the radial needle bearing of the second embodiment.
In the radial needle bearing 20D of this embodiment, the washer 9 is composed of two members, the floating bush 17 is formed integrally with one of them to form a washer 9B with a floating bush, and the spacer 18 is also integrated with the floating bush. The spacer 18A with the floating bush is formed.

  More specifically, the washer 9 has an outer diameter side washer 9B having an outer end face facing the support plate 4f and an inner end face facing the planetary gear 4c, and a smaller diameter than the outer diameter side washer 9B, and the outer end face is supported. The inner diameter side washer 9C is opposed to the plate 4f and the inner end surface is opposed to the cage 10. The outer diameter side washer 9B is provided with an extending portion 93 extending inward in the axial direction from the inner diameter end portion. ing. The extending portion 93 is disposed between the cage 10 and the planetary gear 4c, rotates relative to the cage outer peripheral surface 15 and the planetary gear inner peripheral surface 4c1, and functions as a floating bush.

  The spacer 18A with the floating bush is the same as the spacer 18A with the floating bush of the second modification described above.

According to the radial needle bearing 20D of the present embodiment configured as described above, the floating bush 17 can be manufactured integrally with the washer 9 and the spacer 18, so that the manufacturing cost can be reduced at a low cost. Further, a general-purpose one can be used as the inner diameter side washer 9C. Furthermore, when it is difficult to secure a space for arranging the washer 9A with the floating bush described in the second modification, for example, the notch 19 (see FIG. 5) or the notch 4c2 (see FIG. 6) cannot be provided. Etc.
In the present embodiment, the outer diameter side washer 9B and the spacer 18A are integrated with the floating bush 17, respectively. However, the present invention is not limited to this, and the floating bush 17 and the outer diameter side washer 9B, and the floating bush 17 and the inner diameter side washer 9C. It is sufficient that at least one of the floating bush 17 and the spacer 18 is formed integrally.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. For example, the following improvements can be made to the above embodiment.
(1) Grind at least one of the outer peripheral surface of the cage and the inner peripheral surface of the planetary gear. Thereby, sliding friction can be reduced.
(2) For the same purpose, a surface treatment layer capable of reducing friction is provided on at least one of the outer peripheral surface of the cage and the inner peripheral surface of the planetary gear. As the surface treatment layer for reducing such friction, for example, those shown in the following (i) to (vi) can be used.
(I). Reaction layer of a compound of sulfur and iron.
(Ii). A reaction layer of a compound of sulfur and iron containing nitrogen.
(Iii). Reaction layer of phosphate compound of phosphorus and iron.
(Iv). A treatment layer obtained by firing a simple substance or a mixture of molybdenum disulfide (MoS ₂ ) and polytetrafluoroethylene (PTFE) together with a thermosetting synthetic resin.
(V). A layer obtained by firing a single or mixture of MoS ₂ and PTFE together with a thermosetting synthetic resin on the surface of any one of the reaction layers (i) to (iii) above.
(Vi). Surface treatment layer with diamond-like carbon (DLC).

  Moreover, although the said 1st-3rd modification was described as a modification of 2nd Embodiment of a radial needle bearing, it is not restricted to this, In the radial needle bearing of 1st Embodiment, a floating washer is attached with these floating bushes. It may be a washer.

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 Washer 9A, 9B Washer with floating bush (floating bush)
DESCRIPTION OF SYMBOLS 10 Cage 15 Cage outer peripheral surface 16 Needle 17 Floating bush 18 Spacer 18A Spacer with floating bush (floating bush)
20, 20A, 20B, 20C, 20D Radial needle bearings

Claims (3)

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 plurality of needles arranged at predetermined intervals in the circumferential direction;
A cage that holds the needle in a rollable manner and is used in an outer diameter guide;
A radial needle bearing comprising: a floating bush disposed between the retainer and the pinion gear and capable of rotating relative to the retainer outer peripheral surface and the pinion gear inner peripheral surface. The pinion shaft is supported by a support plate provided at an axial end,
A washer is provided between the outer end surface of the pinion gear and the inner end surface of the support plate,
The radial needle bearing according to claim 1, wherein the floating bush is formed integrally with the washer. 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 floating bush is formed integrally with the spacer.

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