CN110382891B

CN110382891B - Needle roller with retainer and planetary gear mechanism support structure having the same

Info

Publication number: CN110382891B
Application number: CN201880015863.2A
Authority: CN
Inventors: 冨加见理之; 土屋将
Original assignee: NTN Corp
Current assignee: NTN Corp
Priority date: 2017-03-06
Filing date: 2018-03-02
Publication date: 2021-05-25
Anticipated expiration: 2038-03-02
Also published as: KR20190119052A; WO2018164014A1; CN110382891A; KR102508641B1

Abstract

The holder has: outer diameter side roller stoppers provided at both axial end portions on the outer diameter side of the roller pitch circle diameter; and an inner diameter side roller stopper portion provided at an axially central portion on an inner diameter side of the roller pitch circle diameter. The outer diameter side roller stopper and the inner diameter side roller stopper are arranged so as not to overlap in the axial direction. The needle roller is a convex roller having a cylindrical surface portion with a constant diameter in a central region and inclined surface portions on both sides of the cylindrical surface portion. The boundary between the cylindrical surface portion and the inclined surface portion of the needle roller is disposed between the outer diameter side roller stopper portion and the inner diameter side roller stopper portion of the retainer. The boundary between the cylindrical surface portion and the inclined surface portion of the needle roller is not in contact with the retainer.

Description

Needle roller with retainer and planetary gear mechanism support structure having the same

Technical Field

The present invention relates to a needle roller with a retainer and a planetary gear mechanism support structure having the needle roller with a retainer.

Background

The needle roller with the retainer is composed of a plurality of needle rollers and a retainer, and the retainer comprises: a pair of annular portions separated in the axial direction; and a plurality of column portions extending in the axial direction and connecting the annular portions to each other. Further, the needle rollers are held in the concave portions formed between the column portions adjacent in the circumferential direction. In addition, in the needle roller, in order to avoid an edge load (edge load) with the partner member (excessive pressure generated at the end of the contact region when the roller comes into contact with the raceway surface), a crowned roller having a cylindrical surface portion with a constant diameter in the central region and inclined surface portions provided on both sides of the cylindrical surface portion may be used.

Conventionally, as described in patent document 1, Dp < a is satisfied where Dp is a length from an end surface of a roller to a boundary portion between a cylindrical surface portion and an inclined surface portion, and a shortest distance in an axial direction from a wall surface of a recess portion facing the end surface of the roller to a retainer guide surface is a.

By setting in this manner, the length of the inclined surface portion can be adjusted so that the boundary portion between the cylindrical surface portion and the inclined surface portion does not contact the guide surface, thereby providing a long-life roller with a retainer.

Further, conventionally, as described in patent document 2, in a retainer, an inner protrusion and an outer protrusion for preventing a roller from coming off are provided on an inner diameter side and an outer diameter side of both sides in an axial direction of a column portion. In this case, a crowned roller is used which is composed of a central straight portion (cylindrical surface portion) and crowned portions (inclined surface portions) on both sides of the central straight portion. The inner protrusion and the outer protrusion of the pillar portion are provided on the convex portion side of the contact mark (boundary portion) between the straight portion (cylindrical surface portion) and the convex portion (inclined surface portion) on both sides of the straight portion (cylindrical surface portion).

With such a configuration, the gap between the outer peripheral surface of the roller and the inner and outer projecting portions of the pillar portion is increased. Therefore, the inner and outer protrusions do not scrape off the lubricant on the outer surface of the roller, and dust such as metal abrasion powder mixed in the lubricant does not remain on the inner and outer protrusions. This allows the lubricating oil to smoothly flow through the gap between the roller and the recess.

Further, conventionally, as described in patent document 3, in the retainer, oil grooves extending radially inward and outward are provided at 3 locations, i.e., at the axial middle and the axial both ends of each of the column portions between the respective concave portions adjacent in the circumferential direction. In this case, a crowned roller is used which is composed of a cylindrical region (cylindrical surface portion) and crowned regions (inclined surface portions) on both sides of the cylindrical region (cylindrical surface portion). The oil grooves provided at both ends in the axial direction have end edges near the axial center arranged at the following positions: a position corresponding to a connecting portion between a cylindrical region and a convex region on the outer peripheral surface of the roller in a state of being accommodated in the recess; or closer to the axial center of the roller than the connecting portion.

By setting in this manner, it is possible to prevent the oil film on the roller guide surface from being insufficient, and to stabilize the rotational operation of the roller.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2008-215475

Patent document 2: japanese laid-open patent publication No. 2013-87886

Patent document 3: japanese laid-open patent application No. 2001-41250

Disclosure of Invention

Problems to be solved by the invention

In order to facilitate assembly of the roller with the retainer (needle roller with the retainer) to the shaft or the housing, it is desirable that the roller is configured not to fall off the retainer. In the structure described in patent document 1, the roller stopper portion for holding the roller is formed of the 1 st linear portion located on the radially outer side of the pillar portion. In this case, the roller needs to be smaller than the roller diameter so as not to come off. However, when such setting is performed, the gap between the portion where the roller stopper portion exists and the roller becomes small, so that the lubricant is hard to enter, and wear and peeling due to poor lubrication are likely to occur.

In addition, in patent document 1, Dp (the length from the end surface of the roller to the boundary between the cylindrical surface portion and the inclined surface portion) < a (the shortest distance in the axial direction from the wall surface of the recess portion facing the end surface of the roller to the retainer guide surface) is set, and therefore the boundary between the cylindrical surface portion and the inclined surface portion of the roller overlaps the roller stopper at the axial position. Therefore, the boundary portion between the roller cylindrical surface portion and the inclined surface portion, which generates the edge surface pressure in the case where the shaft and the housing to be attached are inclined, is likely to be worn and peeled off due to poor lubrication.

In the structure described in patent document 2, both the inner projecting portion and the outer projecting portion as the roller stopper portions are located on both sides of the pillar portion in the axial direction and are located at substantially the same position in the axial direction, and therefore, there is a possibility that the inflow property of the lubricating oil is deteriorated.

In the structure described in patent document 3, if the contact surface pressure between the roller and the bearing ring is to be reduced, for example, when the inclination of the shaft is large, the crowning length may be increased. However, if the crowning length is extended, the roller stopper is moved toward the axial center side. Therefore, the roller is held on the axial center side, and the inclination amount of the roller becomes larger with respect to the retainer. If the inclination of the roller is increased, the following problems are present: when the needle roller with the retainer is assembled to the shaft or the housing, the roller easily interferes with the inside in the radial direction of the shaft or the housing, and the assembly is difficult. In addition, in patent document 3, as in patent document 2, both the inner protrusion and the outer protrusion as the roller stopper are located on both sides of the pillar portion in the axial direction and are located at almost the same position in the axial direction, and therefore, there is a possibility that the inflow property of the lubricating oil is deteriorated.

In view of the above problem, the present invention provides a needle roller with a retainer and a planetary gear mechanism support structure having the needle roller with a retainer as follows: the portion with high edge surface pressure is not easily lubricated badly to inhibit the generation of abrasion and stripping, and can prevent the roller from falling off without damaging the flowing-in property of the lubricating oil.

Means for solving the problems

The needle roller with a retainer of the present invention is constituted by a plurality of needle rollers and a retainer, wherein the retainer comprises: a pair of annular portions separated in the axial direction; and a plurality of column portions extending in the axial direction and connecting the annular portions to each other, the retainer including: outer diameter side roller stoppers provided at both axial end portions on the outer diameter side of the roller pitch circle diameter; and an inner diameter side roller stopper provided at a position closer to an inner diameter side than a roller pitch circle diameter in a central portion in an axial direction, the outer diameter side roller stopper and the inner diameter side roller stopper being arranged so as not to overlap in the axial direction, the needle roller being a convex roller having a cylindrical surface portion with a fixed diameter in a central region and having inclined surface portions on both sides of the cylindrical surface portion, a boundary portion between the cylindrical surface portion and the inclined surface portion of the needle roller being arranged between the outer diameter side roller stopper and the inner diameter side roller stopper of the retainer, and the boundary portion between the cylindrical surface portion and the inclined surface portion of the needle roller not being in contact with the retainer.

According to the needle roller with the retainer of the present invention, the retainer has the outer diameter side roller stopper portion and the inner diameter side roller stopper portion, and therefore, the needle roller can be effectively prevented from falling off. Further, the boundary between the cylindrical surface portion and the inclined surface portion of the roller is disposed closer to the axial center side than the outer diameter side roller stopper portion as follows: the boundary portion does not overlap with a roller stopper portion for preventing the roller from dropping out from the retainer to the outside in the radial direction in the axial direction, and therefore, a lubrication failure is less likely to occur in a portion having a high edge surface pressure. Further, even if the convex surface length is long, assembly is not difficult when assembling to the radial inside of the shaft or the housing to be mounted.

Further, the space between the retainer and the roller is provided so that the inner diameter side roller stopper portion is not disposed on the inner diameter side of the outer diameter side roller stopper portion, and the roller stopper portions are located at the axial positions of both (the inner diameter side and the outer diameter side), whereby deterioration in the inflow property of the lubricating oil can be reduced. Further, since the boundary between the cylindrical surface portion and the inclined surface portion of the roller is disposed on both axial end sides of the inner diameter side roller stopper portion, poor lubrication is less likely to occur in a portion having a high edge surface pressure. The axial position of the boundary between the cylindrical surface portion and the inclined surface portion of the roller is located at a connecting portion (inclined portion) between the outer diameter side roller stopper portion and the inner diameter side roller stopper portion of the retainer, but this portion is configured not to contact the retainer. This makes it difficult for a lubrication failure to occur in a portion having a high edge surface pressure.

Preferably, the retainer has an inclined connecting portion connecting the outer diameter side roller stopper portion and the inner diameter side roller stopper portion, and the inclined connecting portion has a notched shape avoiding interference with the needle rollers.

Preferably, a recessed portion in which the needle rollers are arranged is formed between circumferentially adjacent column portions of the retainer, and the recessed portion radially expands from an inner diameter side to an outer diameter side. The retainer may be a welded joint product of steel plates punched with concave portions.

In addition, the roller bearing has the following advantages: since the rollers as the rolling elements are in line contact with the raceway, the load capacity is high. On the other hand, it is known that a surface pressure concentration called an edge load tends to occur at an end portion of an effective contact portion between the roller and the raceway surface, and when the surface pressure concentration is excessively large, the life of the bearing is reduced. In order to avoid the occurrence of the edge load, in general, when designing a roller bearing, a convex surface having a non-linear generatrix shape is formed on at least one of an outer circumferential surface (rolling surface) of a roller, an outer ring raceway surface, and an inner ring raceway surface. In addition, as the convex surface for suppressing the edge load and making the contact surface pressure uniform, it is preferable to express the generatrix shape of the convex surface by a logarithmic curve. Therefore, the needle roller is preferably a logarithmic convex shape such as a shape approximated by a logarithmic function.

Preferably, the needle roller is a needle roller as a crowning roller having a logarithmic crowning shape approximated by a logarithmic function, wherein a contour line of the crowning surface in a cross section in an axial direction is expressed by equation 1 using a y-z coordinate system having a generatrix of any one of an inner ring raceway surface, an outer ring raceway surface and a roller rolling surface as a y-axis and a generatrix vertical direction as a z-axis, and an axial length of the cylindrical surface portion is 40% to 70% of a total length of the roller,

[ equation 1]

Wherein, in equation 1, a is expressed by equation 2 below, a is a length from an origin taken on a generatrix of any one of the inner race raceway surface, the outer race raceway surface, and the roller rolling surface to an end of the effective contact portion,

[ equation 2]

A＝2K₁Q/πLE’，

Q is the load, and Q is the load,

l is the length of the effective contact part of the roller and the inner ring or the outer ring in the generatrix direction,

e' is the equivalent elastic modulus.

With the needle roller configured as described above, even when the inclination of the bearing is small, the contact surface pressure does not become excessively large, and even when the inclination of the bearing is large, edge loading does not easily occur.

The retainer may be M-shaped having an inwardly facing flange at an outer end of the annular portion, or V-shaped having no inwardly facing flange at an outer end of the annular portion.

The planetary gear mechanism support structure of the present invention is a support structure for supporting a planetary gear mechanism, the planetary gear mechanism having: an internal gear; a sun gear disposed at the center of the internal gear; a plurality of planetary gears that mesh with the internal gear and the sun gear; and a carrier that supports the planetary gear, wherein the planetary gear is rotatably supported by a pinion shaft via a rolling bearing, the pinion shaft is provided to the carrier, and the rolling bearing is formed by the needle roller with the retainer.

The planetary gear mechanism support structure of the present invention uses the needle roller with the retainer for the rolling bearing, and therefore can effectively prevent the needle roller from falling off. Further, even if the length of the convex surface is long, it is not difficult to assemble the housing when the housing is assembled to the inside in the axial or radial direction of the housing. In addition, deterioration of the inflow property of the lubricating oil can be reduced. Further, lubrication failure is less likely to occur in portions of high edge surface pressure.

The outer diameter surface of the pinion shaft may be an inner raceway surface, the inner diameter surface of the planetary gear may be an outer raceway surface, retainers used for the needle rollers with the retainers may be in contact with the outer raceway surface formed by the inner diameter surfaces of the planetary gear at both end portions in the axial direction, and an oil passage hole may be provided in the pinion shaft, the oil passage hole being opened in the inner raceway surface formed by the outer diameter surface of the pinion shaft.

By providing the oil passage hole in this manner, the retainer needle roller can be lubricated. As the cage guide form, from the viewpoint of safety of the cage movement under high speed movement, the cage guide is desired to be the cage guide as compared with the roller guide, and from the viewpoint of lubricating oil operation by the centrifugal force, the outer ring guide is preferred to be the inner ring guide.

The planetary gear mechanism support structure can be used for a transmission for an automobile.

When used in an automobile transmission as described above, the amount of lubricating oil is small because the structure is such that the lubricating oil enters the oil hole of the pinion shaft (support shaft) by spraying. Therefore, the planetary gear mechanism support structure is most suitably used for a transmission of an automobile.

ADVANTAGEOUS EFFECTS OF INVENTION

In the present invention, poor lubrication is less likely to occur in portions with high edge surface pressure, and the occurrence of wear and separation can be suppressed, and deterioration in the inflow of lubricating oil can be effectively prevented. Therefore, the needle roller with the retainer can be provided with excellent durability. Moreover, the roller can be effectively prevented from dropping off. In addition, even if the roller has a long crowning length, the roller is excellent in assembling property when assembled to the inside in the radial direction of the shaft or the housing.

Drawings

Fig. 1 is a sectional view of a needle roller with a retainer according to the present invention.

Fig. 2 is an enlarged sectional view of a main portion of the retainer of the needle roller with the retainer shown in fig. 1.

Fig. 3 is an enlarged view of the recess of the retainer.

Fig. 4 is an enlarged sectional view taken along line a-a of fig. 2.

Fig. 5 is a side view of a needle roller with a retainer of the present invention.

Fig. 6 is an enlarged sectional view of a main portion of another embodiment of the retainer.

Fig. 7 is a schematic diagram of the planetary gear mechanism.

Fig. 8 is a sectional view of a support structure of the planetary gear mechanism.

Fig. 9 is a main part sectional view of a transmission for an automobile.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to fig. 1 to 9. Fig. 1 shows a needle roller 30 with a retainer, and the needle roller 30 with a retainer is configured by assembling a plurality of needle rollers 1 to a retainer 2. In the following description, a direction along the center axis of the needle roller 30 with the retainer is referred to as an "axial direction", a direction perpendicular to the center axis is referred to as a "radial direction", and a direction along an arc centered on the center axis is referred to as a "circumferential direction".

The holder 2 has: a pair of

annular portions

3, 3 separated in the axial direction; and a plurality of column parts 4 extending in the axial direction and connecting the

annular parts

3, 3 to each other. A plurality of recesses 5 having the shape shown in fig. 3 are formed between the

column parts

4 and 4 adjacent to each other in the circumferential direction, and the needle rollers 1 are disposed in the recesses 5. As shown in fig. 2, the cross-sectional shape of the retainer 2 is substantially M-shaped, and the retainer 2 of the present embodiment is referred to as an M-shaped retainer because of such a cross-sectional shape. The M-shaped retainer has an inwardly facing flange 3a at the outer end of the annular portion 3.

The column portion 4 includes a pair of outer diameter portions 4a, an inner diameter portion 4b, and an inclined portion 4 c. The outer diameter portion 4a extends axially inward from the outer diameter portion of each of the pair of annular portions 3. The inner diameter portion 4b is disposed between the pair of annular portions 3 and on the inner diameter side of the outer diameter portion 4 a. The inclined portion 4c connects the outer diameter portion 4a and the inner diameter portion 4 b.

As shown in fig. 2 and 4, an outer diameter side retaining portion (hereinafter, also referred to as an outer diameter side roller stopper) 6 is formed in the outer diameter portion 4a, and an inner diameter side retaining portion (hereinafter, also referred to as an inner diameter side roller stopper) 7 is formed in the inner diameter portion 4 b. The outer diameter side retaining portion 6 includes: an inner diameter side tapered portion 6a protruding from the inner diameter side toward the outer diameter side into the recess 5; and an outer diameter side tapered portion 6b that protrudes from the outer diameter side toward the inner diameter side into the recess 5. The needle roller 1 disposed in the recess 5 is received by the inner diameter side tapered portion 6 a. The inner diameter side retaining portion 7 includes: an outer diameter side tapered portion 7a protruding from the outer diameter side toward the inner diameter side into the recess 5; and an end surface portion 7b extending radially inward from the inner diameter end of the outer diameter side tapered portion 7 a. The needle roller 1 disposed in the recess 5 is received by the inner diameter side tapered portion 6a and the outer diameter side tapered portion 7 a. Further, if the amount of movement of the roller 1 with respect to the cage 5 can be secured, the inner diameter side tapered portion 6a and the outer diameter side tapered portion 7a may not be provided.

As shown in fig. 5, the needle roller 1 is a crowned roller having a cylindrical surface portion 10 with a constant diameter in a central region and inclined surface portions (hereinafter, also referred to as "crowned surface portions") 11 provided on both sides of the cylindrical surface portion 10.

Generally, roller bearings have the following advantages: since the rollers as the rolling elements are in line contact with the raceway, the load capacity is high. On the other hand, it is noted that surface pressure concentration called edge loading is liable to occur at the end of the effective contact portion of the roller with the raceway surface, and if the surface pressure concentration is excessively large, the bearing life is lowered. In order to avoid the occurrence of the edge load, in general, when designing a roller bearing, a convex surface having a non-linear generatrix shape is formed on at least one of an outer circumferential surface (rolling surface) of a roller, an outer ring raceway surface, and an inner ring raceway surface. As the convex surface for suppressing the edge load to make the contact surface pressure uniform, it is preferable to express the generatrix shape of the convex surface by a logarithmic curve. Therefore, the needle roller 1 of the needle roller with retainer 30 of the present embodiment is preferably a logarithmic convex shape which is approximated by a logarithmic function, for example.

Here, the logarithmic crowning applied to the needle roller 1 will be explained. The generatrix of the convex portions 11b and 11b of the rolling surface 1a of the needle roller 1 is determined from a logarithmic curve of logarithmic convexity represented by the following equation (equation 1). The logarithmic convexity calculation is described in japanese patent No. 4429842 of the present applicant. In this case, the outline of the crowning surface on the cross section in the axial direction of the roller bearing is expressed by equation 1 using a y-z coordinate system in which the generatrix of any one of the inner ring raceway surface, the outer ring raceway surface, and the roller rolling surface is the y-axis and the generatrix vertical direction is the z-axis.

[ equation 1]

In equation 1, a is expressed by equation 2 below, and a is a length from an origin point taken on a generatrix of any one of the inner race raceway surface, the outer race raceway surface, and the roller rolling surface to an end of the effective contact portion.

[ equation 2]

A＝2K₁Q/πLE’

Q: the load is applied to the workpiece to be processed,

l: the length of the effective contact part of the roller and the inner ring or the outer ring in the generatrix direction,

e': equivalent elastic coefficient.

Design parameter K in the above logarithmic convex arithmetic expression₁、K₂And z_mIs the object of the design. The mathematical optimization method of the logarithmic convexity is explained. In determining design parameters K₂By appropriately selecting K in the functional expression representing the logarithmic convexity₁、z_mAn optimal logarithmic convexity can be designed. With regard to the convex surface, it is generally designed to reduce the maximum value of the surface pressure or stress of the contact portion. Here, considering that the rolling fatigue life is generated according to the yield condition of Mises, so that Mises' sK is selected in such a way that the maximum value of the equivalent stress is minimal₁、z_m. K can be selected using a suitable mathematical optimization method₁、z_m. As for the algorithm of the mathematical optimization method, various algorithms have been proposed, one of which is a direct heuristic capable of performing optimization without using a derivative of a function, and is useful in a case where an objective function and a variable cannot be directly expressed by an equation. Here, K is determined by the Rosenbrock method which is one of the direct search methods₁、z_m。

The shape of the

convex portions

11 and 11 of the needle roller 1 of the present embodiment is a logarithmic curve convex surface obtained by the above equation. By setting in this manner, even when the shaft of the needle roller 30 to which the tape holder is attached is inclined, the contact surface pressure can be suppressed to be small, and the life can be prolonged. However, the logarithmic shape is not limited to the above formula, and other logarithmic convex surface formula may be used to obtain the logarithmic curve.

The convex portion 11 of the needle roller 1 is subjected to convex surface processing by machining or barreling. In the tumbling process, a needle roller and an abrasive are put in a barrel to form convex portions at both ends of the needle roller. When the convex portion 11 of the needle roller 1 is crowned by barreling, a position where the amount of reduction from the outer peripheral surface of the cylindrical surface portion 10 (the radially outermost end of the cylindrical surface portion 10) is reduced by, for example, 0.5 μm is preferably set as the boundary portion 12. In addition, when the convex surface portion is formed by barreling, the linear portion (the cylindrical surface portion 10) of the needle roller 1 is also slightly reduced in processing, and it is difficult to define the linear portion. Therefore, it is preferable to define a position reduced by 0.5 μm from the outermost diameter portion of the needle roller 1 as a convex starting point (boundary portion between the cylindrical surface portion 10 and the inclined surface portion 11).

As shown in fig. 5, the axial length L1 of the cylindrical surface portion 10 in the central region of the needle roller 1 is 40% to 70% of the entire length L (roller axial length) of the needle roller 1. When the shape of the convex surface of the needle roller 1 is logarithmic, it has the following characteristics: the amount of initial decrease in convexity is small, and the amount of decrease increases significantly as the end is approached. Therefore, if the straight line passing portion (cylindrical surface portion) 10 is too short, that is, the convex surface length is too long, the amount of decrease in the side close to the end portion becomes large. Therefore, the processing requires a long time and the cost becomes high. On the other hand, if the line crossing part (cylindrical surface part) 10 is too long, that is, the convex surface length is too short, the amount of decrease becomes small. Therefore, in the case where the bearing is inclined, edge loading easily occurs. Here, the amount of decrease refers to the amount of decrease in the radial direction due to the convexity.

Therefore, by setting the axial length L1 of the cylindrical surface portion 10 in the central region to 40% to 70% of the entire length (roller axial length) L of the needle roller 1, the contact surface pressure is not excessively increased even when the inclination of the bearing is small, and edge loading is not easily generated even when the inclination of the bearing is large.

That is, as shown in table 1 below, when the straight length of the straight portion (cylindrical surface portion) 10 is less than 40%, the contact surface pressure is not excessively large when the inclination of the bearing is small, but edge loading is likely to occur when the inclination of the bearing is large. Further, if the straight length of the straight portion (cylindrical surface portion) 10 is greater than 70%, the contact surface pressure does not become excessively large when the inclination of the bearing is large, but tends to become excessively large when the inclination of the bearing is small.

[ Table 1]

Straight length	～40％	40～70％	70％～
				Small inclination	◎	○	△
The inclination is large	△	○	◎

However, in the needle roller 30 with a retainer, a welded retainer is used as the retainer 2 in order to increase the load capacity (to increase the roller length as much as possible and the number of rollers). The manufacturing process of the welded holder is roughly as follows.

(a) As the billet, a strip-shaped steel material obtained by shearing a cold-rolled steel sheet such as SPC having good formability by a shear or the like to a predetermined width is used.

(b) The basic cross-sectional shape (M-shape or V-shape) of the retainer is formed by press working a strip-shaped steel material.

(c) The recesses are punched out at a predetermined pitch in the longitudinal direction of the strip steel material. Then, the strip-shaped steel material is cut into a predetermined length at both ends in consideration of the welding margin.

(d) The strip-shaped steel material is bent into a ring shape.

(e) The two ends are butted and welded together.

Thereafter, heat treatment such as soft nitriding or carburizing and quenching is performed to remove strain caused by welding and form a hardened layer on the surface of the retainer.

The welded holder manufactured in this manner is formed of a thin strip-shaped steel material for bending into a ring shape. Therefore, the width of the punched-out remaining portion to be the pillar portion formed between the adjacent concave portions can be made small, and the length of the concave portion corresponding to the roller length can be made large. Therefore, if the weld holder is used, the roller length can be made longer and the number of rollers can be made larger. Further, by using the retainer 2 as a welded retainer, the recess 5 radially expands from the inner diameter side toward the outer diameter side, and the needle roller 1 can be effectively prevented from contacting the connection portion of the recess 5.

In the retainer of the embodiment, the outer diameter side roller stopper 6 and the inner diameter side roller stopper 7 are arranged so as not to overlap in the axial direction, and the boundary portion 12 between the cylindrical surface portion 10 and the inclined surface portion 11 of the needle roller 1 is arranged so as not to overlap in the axial direction with the outer diameter side roller stopper 6 and the inner diameter side roller stopper 7. Therefore, when the bearing is tilted, an oil film can be secured near the convex starting point (the boundary portion 12 between the cylindrical surface portion 10 and the inclined surface portion 11) at which the contact stress becomes maximum, and the wear, the separation, and the like at the convex starting point can be suppressed, and the life can be extended.

The convex starting point (boundary portion 12 between the cylindrical surface portion 10 and the inclined surface portion 11) of the needle roller 1 is not in contact with the retainer 2. Thus, an oil film at the starting point of the convex surface can be secured, and the wear, peeling, and the like at the starting point of the convex surface can be suppressed, thereby extending the life.

By preventing the start point of the convex surface of the needle roller 1 (the boundary 12 between the cylindrical surface portion 10 and the inclined surface portion 11) from contacting the cage 2, the roundness of the convex surface portion (the inclined surface portion 11) does not need to be excessively small, and abrasion or the like of the start point (the boundary 12 between the cylindrical surface portion 10 and the inclined surface portion 11) can be prevented. Specifically, the roundness of the convex surface portion (inclined surface portion 11) of the needle roller 1 may be set to 0.6 μm to 2.0 μm.

Further, by adopting the logarithmic shape for the convex shape of the needle roller 1, the contact surface pressure can be suppressed to be small even when the shaft is inclined, and the life can be further extended.

As shown in fig. 1, in the retainer 2, the outer diameter side retaining portion 6 is disposed on the outer diameter side of the pitch circle diameter PCD of the roller, and the inner diameter side retaining portion 7 is disposed on the inner diameter side of the pitch circle diameter PCD. Thus, the outer diameter side retaining part 6 and the inner diameter side retaining part 7 are set so as not to overlap in the axial direction. That is, the outer diameter side retaining portion 6 is offset axially outward relative to the inner diameter side retaining portion 7.

As shown in fig. 1, in a state where the needle roller 1 is disposed in the recess 5 of the retainer 2, a boundary portion 12 between the cylindrical surface portion 10 and the inclined surface portion 11 of the needle roller 1 corresponds to the inclined portion 4c connecting the outer diameter portion 4a and the inner diameter portion 4 b. Therefore, the boundary portion 12 of the needle roller 1 is not overlapped with the outer diameter side retaining portion 6 and the inner diameter side retaining portion 7 in the axial direction. That is, the boundary portion 12 is offset with respect to the outer diameter side retaining portion 6 and the inner diameter side retaining portion 7.

In this case, the inclined portion 4c connecting the outer diameter portion 4a and the inner diameter portion 4b constitutes a connecting portion 8 connecting the outer diameter side retaining portion 6 and the inner diameter side retaining portion 7, and the connecting portion 8 has a notched shape as shown in fig. 3. That is, the inclined portion 4c is provided with a notch portion (cutout portion) 9 having an inequilateral triangular shape. The boundary portion 12 between the cylindrical surface portion 10 and the inclined surface portion 11 of the needle roller is set to be disposed between the outer diameter side roller stopper portion 6 and the inner diameter side roller stopper portion 7 of the retainer 2 (i.e., a position corresponding to the connecting portion 8), and the boundary portion 12 is set not to contact the connecting portion 8.

As described above, the retainer 2 of the needle roller with retainer 30 shown in fig. 2 is configured as an M-shaped retainer as described above, but may be a retainer called a V-shaped retainer as shown in fig. 6. The M-shaped retainer shown in fig. 2 has a flange 3a facing inward at the outer end of the annular portion 3, whereas a structure called a V-shaped retainer does not have such a flange as shown in fig. 6. Therefore, in the present embodiment, the M-shaped retainer shown in fig. 2 may be used, or the V-shaped retainer shown in fig. 6 may be used.

The needle roller with cage 30 of the present embodiment can be used for a support structure for supporting the planetary gear mechanism S as shown in fig. 7. The planetary gear mechanism S has: an internal gear (ring gear) 15; a sun gear (sun) 16 disposed at the center of the internal gear 15; and a plurality of planetary gears (pinions) 17 that mesh with the internal gear 15 and the sun gear 16.

That is, the sun gear 16 is located at the center of the large internal-tooth gear 15, and the plurality of planetary gears 17 are interposed between the internal-tooth gear 15 and the sun gear 16. As shown in fig. 8, each planetary gear 17 is rotatably supported by a pinion shaft 18a of the carrier 18.

In this case, the needle rollers 30 with the cage are disposed between the pinion shaft 18a and the planetary gear 17, and the needle rollers 30 with the cage can constitute a support structure for supporting the planetary gear mechanism S by rotatably supporting the planetary gear 17 on the pinion shaft 18 a.

The cage 2 of the needle roller with cage 30 has the outer diameter surface of the pinion shaft 18a as the inner raceway surface and the inner diameter surface of the planetary gear 17 as the outer raceway surface. The cage 2 has outer diameter guide surfaces 20 (see fig. 1) at both axial ends thereof, which contact outer raceway surfaces formed by inner diameter surfaces of the planetary gears 17. Here, as shown in fig. 1, the outer diameter guide surface 20 is a range H from the annular portion 3 to a part of the column portion in the outer peripheral surface of the retainer 2. When rotating, the cage 2 is guided by the outer diameter guide surface 20 to contact the inner peripheral surface (inner diameter surface) of the pinion (planet gear) 17. Thus, the holder 2 is of the so-called outer ring guide type.

However, as the cage guide form, from the viewpoint of safety of the cage movement at high speed, the cage guide is desired to be the cage guide as compared with the roller guide, and from the viewpoint of lubricating oil operation by centrifugal force, the outer ring guide form is preferred to be the inner ring guide form.

Further, an oil passage hole 18b for supplying lubricating oil is formed inside the pinion shaft 18 a. The oil passage hole 18b includes: a 1 st oil passage hole 18ba extending in the axial direction of the pinion shaft 18 a; and a 2 nd oil passing hole 18bb extending from the 1 st oil passing hole 18ba in the radial direction of the pinion shaft 18 a. The 2 nd oil passing hole 18bb communicates the 1 st oil passing hole 18ba with the outer peripheral surface of the pinion shaft 18 a. Further, the 2 nd oil passage hole 18bb is provided at a position axially overlapping the needle roller 30 with the retainer. Accordingly, the lubricating oil is introduced through the oil passage hole 18b formed in the pinion shaft 18a and guided to the outer peripheral surface of the pinion shaft 18a, thereby lubricating the needle roller 30 with the retainer.

Since the retainer 2 has the outer diameter side roller stopper 6 and the inner diameter side roller stopper 7, the needle rollers 1 can be effectively prevented from falling off. Further, the boundary portion 12 between the cylindrical surface portion 10 and the inclined surface portion 11 of the roller 1 is arranged closer to the axial center side than the outer diameter side roller stopper portion 6 as follows: the boundary portion 12 does not overlap with a roller stopper portion for preventing the roller 1 from dropping out from the cage 2 to the outside in the radial direction in the axial direction, and therefore, a lubrication failure is less likely to occur in a portion having a high edge surface pressure. Further, since the boundary portion between the cylindrical surface portion and the inclined surface portion of the roller is arranged so as not to overlap the outer diameter side roller stopper portion and the inner diameter side roller stopper portion in the axial direction, when the bearing is inclined, an oil film can be secured in the vicinity of the start point of the convex surface where the contact stress is the largest (in the vicinity of the boundary portion between the cylindrical surface portion and the inclined surface portion), and the occurrence of abrasion, separation, and the like at the start point of the convex surface can be suppressed, whereby the life of the bearing can be prolonged. Further, even if the convex surface length is long, it does not become difficult to assemble when assembling to the inside in the radial direction of the shaft or the housing.

Further, by providing a space between the cage 2 and the roller 1 so that the inner diameter side roller stopper 7 is not disposed on the inner diameter side of the outer diameter side roller stopper 6 and by positioning the

roller stoppers

6 and 7 at both (inner diameter side and outer diameter side) axial positions, it is possible to reduce deterioration in the inflow property of the lubricating oil. In particular, in the planetary gear mechanism support structure, when the retainer 2 is of the outer ring guide type, since the area of the contact guide portion between the outer diameter guide surface of the retainer 2 and the inner peripheral surface of the pinion shaft 18 is large, the oil permeability toward the end portion of the needle roller 1 and the oil permeability toward the lubricating oil between the outer diameter guide surface of the retainer 2 and the inner peripheral surface of the pinion shaft 18 are important. Therefore, it is effective to use the needle roller 30 with the retainer. In the above embodiment, the outer diameter guide surface and the boundary 12 between the cylindrical surface portion 10 and the inclined surface portion 11 of the needle roller 1 are arranged so as not to overlap in the axial direction position. By setting in this manner, when the bearing is inclined, an oil film can be secured near the convex start point (near the boundary between the cylindrical surface portion and the inclined surface portion) where the contact stress is maximum, and the occurrence of abrasion, separation, and the like at the convex start point can be suppressed, thereby enabling the life to be prolonged.

Further, the boundary portions 12 between the cylindrical surface portion 10 and the inclined surface portion 11 of the roller 1 are arranged on both axial end sides of the inner diameter side roller stopper 7, so that lubrication failure is less likely to occur in a portion having a high edge surface pressure. The axial position of the boundary 12 between the cylindrical surface portion 10 and the inclined surface portion 11 of the roller 1 is at the connecting portion (inclined portion) 8 between the outer diameter side roller stopper 6 and the inner diameter side roller stopper 7 of the retainer 2, but this portion 8 is configured not to contact the retainer 2. This ensures an oil film at the starting point of the convex surface, and can suppress the occurrence of abrasion, peeling, and the like at the starting point of the convex surface, thereby extending the life of the device. Further, it is not necessary to make the roundness of the convex surface portion (inclined surface portion) too small, and abrasion or the like at the start point of the convex surface can be prevented. By preventing the start point of the convex surface of the needle roller 1 (the boundary 12 between the cylindrical surface portion 10 and the inclined surface portion 11) from contacting the cage 2, the roundness of the convex surface portion (the inclined surface portion 11) does not need to be excessively small, and abrasion or the like of the start point (the boundary 12 between the cylindrical surface portion 10 and the inclined surface portion 11) can be prevented. Specifically, the roundness of the convex surface portion (inclined surface portion 11) of the needle roller 1 may be set to 0.6 μm to 2.0 μm.

Therefore, in the present embodiment, lubrication failure is less likely to occur in a portion with a high edge surface pressure, and occurrence of wear and separation can be suppressed, and deterioration in the inflow property of the lubricating oil can be effectively prevented. Therefore, the needle roller 30 with the retainer can be provided appropriately and with excellent durability. Further, even if the roller 1 has a long crowning length, the roller is excellent in assembling property when assembled to the inside in the radial direction of the shaft or the housing.

In addition, since the cutout portion 9 is provided in the holder 2, the lubricating oil is guided between the outer diameter guide surface 20 and the inner peripheral surface of the planetary gear 17 through the cutout portion 9. Thereby, an oil film can be formed between the outer peripheral surface (the outer diameter guide surface 20) of the retainer 2 and the inner peripheral surface of the planetary gear 17, and friction can be reduced, which also contributes to an increase in the life of the needle roller 30 with the retainer.

The retainer 2 is formed by rolling up a steel plate punched with a hole to be the recess 5 and integrating the joint portions by welding. That is, the holder 2 is formed of a welded joint product of steel plates punched with the concave portions 5. If formed in this way, the recessed portions 5 radially expand from the inner diameter side toward the outer diameter side, and the rollers 1 can be effectively prevented from contacting the connecting portions of the recessed portions 5 of the cage 2.

As shown in fig. 9, the needle roller with cage 30 of the present embodiment may be used as a support bearing for the transmission T. That is, the needle roller with holder 30 is a needle roller with holder for an automobile. The transmission T is provided with two planetary gear mechanisms S, S, which in turn transmit rotation. In each planetary gear mechanism S, S, a planetary gear 26 is provided on the support shaft 25 via a needle roller 30 with a holder. In this case, the outer diameter surface of the support shaft 25 is an inner raceway surface, and the inner diameter surface of the planetary gear 26 is an outer raceway surface. The cage 2 has outer diameter guide surfaces 20 (see fig. 1) at both axial ends thereof, which contact outer raceway surfaces formed by inner diameter surfaces of the planetary gears 26.

In the case where the planetary gear mechanism is used for a transmission of an automobile, a configuration is adopted in which the oil hole 27 of the support shaft (pinion shaft) 25 is entered by spraying, and therefore the amount of lubricating oil is small. In addition, the needle roller with a cage used in the transmission is used under an excessive environment such as an edge stress due to a centrifugal force or an offset load. Therefore, the needle roller with retainer 30 of the present embodiment is most suitable for use in a transmission of an automobile.

While the present embodiment has been described above, the present embodiment is not limited to the above-described embodiment, and various modifications are possible, and the shapes of the outer diameter side roller stopper 6 and the inner diameter side roller stopper 7 may be different from those shown in fig. 4 as long as there is a range satisfying the roller diameter > the size between the roller stopper 6, the roller stopper 7, and the roller stopper 7 adjacent in the circumferential direction in a part thereof. The outer diameter side roller stopper 6 may be provided on the entire outer diameter portion 4a of the pillar portion 4, or may be provided on a part of the outer diameter portion 4a of the pillar portion 4. The inner diameter side roller stopper 7 may be provided on the entire inner diameter portion 4b of the column portion 4, or may be provided on a part of the inner diameter portion of the column portion. The needle rollers 30 with retainers may be single-row or multi-row.

Industrial applicability

As the needle roller with the retainer, a crowned roller is used which has a cylindrical surface portion with a constant diameter in a central region and inclined surface portions provided on both sides of the cylindrical surface portion, and the needle roller with the retainer may be single row or multiple rows.

Description of the reference symbols

1: a needle-like roller; 2: a holder; 3: an annular portion; 3 a: a flange; 4: a pillar portion; 5: a recess; 6: an outer diameter side roller stopper portion; 7: an inner diameter side roller stopper portion; 8: a connecting portion; 10: a cylindrical surface portion; 11: an inclined surface portion; 12: a boundary location; 15: an internal gear; 16: a sun gear; 17: a planet wheel; 18: a planet carrier; 18 a: a pinion shaft; 20: an outer diameter guide surface; 30: a needle roller with a retainer; s: a planetary wheel mechanism; PCD: pitch circle diameter.

Claims

1. A needle roller with a retainer comprising a plurality of needle rollers and a retainer,

the holder has:

a pair of annular portions separated in the axial direction; and

a plurality of column portions extending in the axial direction and connecting the annular portions to each other,

the holder has:

outer diameter side roller stoppers provided at both ends of the retainer in the axial direction on the outer diameter side of the roller pitch circle diameter;

an inner diameter side roller stopper portion provided at a central portion in an axial direction of the retainer on an inner diameter side with respect to a roller pitch circle diameter; and

an inclined connecting portion connecting the outer diameter side roller stopper portion and the inner diameter side roller stopper portion,

the outer diameter side roller stopper portion and the inner diameter side roller stopper portion are arranged so as not to overlap in the axial direction,

the needle roller is a crowned roller having a cylindrical surface portion with a fixed diameter at a central region thereof and inclined surface portions at both sides of the cylindrical surface portion,

the cylindrical surface portion corresponds to a boundary portion of the inclined surface portion and the inclined connecting portion, and the inclined connecting portion has a notch shape avoiding contact with the needle roller, and even when the inclination occurs, the boundary portion, which is a portion where the edge surface pressure may occur, does not contact the inclined connecting portion.

2. The needle roller with holder as set forth in claim 1,

a recess in which the needle roller is disposed is formed between circumferentially adjacent column portions of the retainer,

the recess radially expands from the inner diameter side to the outer diameter side.

3. The needle roller with holder as set forth in claim 2,

the retainer is a welded joint product of steel plates from which the concave portion is punched.

4. The needle roller with holder as claimed in claim 1 or 2,

the needle roller is a logarithmic convex shape that is approximated by a logarithmic function.

5. The retainer-equipped needle roller as claimed in claim 4,

the needle roller is a needle roller as a crowning roller, wherein the crowning roller is a logarithmic crowning shape of a shape approximated by a logarithmic function,

a contour line of the convex surface in the axial direction cross section is expressed by equation 1 using a y-z coordinate system in which a generatrix of any one of the inner ring raceway surface, the outer ring raceway surface, and the roller rolling surface is a y-axis and a generatrix vertical direction is a z-axis,

and the axial length of the cylindrical surface part is 40 to 70 percent of the total length of the roller,

equation 1

equation 2

A＝2K₁Q/πLE'，

Q is the load, and Q is the load,

e' is the equivalent elastic modulus.

6. The needle roller with holder as claimed in claim 1 or 2,

the retainer is M-shaped having an inwardly facing flange at an outer end of the annular portion, or V-shaped having no inwardly facing flange at an outer end of the annular portion.

7. A planetary gear mechanism supporting structure which supports a planetary gear mechanism,

this planet wheel mechanism has:

an internal gear;

a sun gear disposed at the center of the internal gear;

a plurality of planetary gears that mesh with the internal gear and the sun gear; and

a planet carrier that supports the planet gear,

it is characterized in that the preparation method is characterized in that,

the planetary gear is rotatably supported by a pinion shaft provided to the carrier via a rolling bearing constituted by the needle roller with a retainer according to any one of claims 1 to 6.

8. The planetary-gear-mechanism support structure according to claim 7,

the outer diameter surface of the pinion shaft is defined as an inner raceway surface, and the inner diameter surface of the planetary gear is defined as an outer raceway surface, and the retainers used in the needle rollers with the retainers are in contact with the outer raceway surface defined by the inner diameter surfaces of the planetary gear at both ends in the axial direction, and an oil passage hole that opens in the inner raceway surface defined by the outer diameter surface of the pinion shaft is provided inside the pinion shaft.

9. The planetary-gear-mechanism support structure according to claim 7 or 8,

the planetary gear mechanism support structure is used for a transmission for an automobile.