JP2022149822A - Cage and needle roller with cage - Google Patents

Abstract

To provide: a cage which is optimum to a planetary gear; and needle rollers with the cage.SOLUTION: In a state that each of needle rollers (2), which are accommodated respectively in pockets (40) of a cage, has a pair of flat faces (21) constituting both end faces in an axial direction, and angular parts (22) intersecting respectively with the flat faces, and each chamfered into a circular-arc shape with a radius as r1, the cage comprises: circular-arc shaped relief parts (61) each arranged at four corner parts (35) of the pocket within a range of the pocket in the axial direction with a radius r2 set larger than the radius r1; and protrusions (62) each formed at an inside face (34b) of an annular part facing the pocket, and contacting with the flat faces of the needle roller. A protrusion dimension of the protrusion is defined according to a difference between the radius r1 and the radius r2.SELECTED DRAWING: Figure 6

Description

TECHNICAL FIELD The present invention relates to a retainer and needle rollers with retainer, and more particularly to a retainer and needle rollers with retainer used for a planetary gear of a planetary reduction mechanism.

In order to improve the lubricity of the sliding surfaces of the cage and the rollers, there have been conventionally proposed techniques for improving the oil permeability in the pockets of the cage. For example, in Japanese Patent Application Laid-Open No. 2004-144244 (Patent Document 1), concave grooves extending from the inner circumference to the outer circumference are formed on the inner wall surface in the circumferential direction of the pocket at predetermined intervals along the axial direction. A cage is disclosed in which protrusions are formed on the direction inner wall surfaces to contact the central portions of the end surfaces of the rollers.

Further, Japanese Patent Application Laid-Open No. 2011-214702 (Patent Document 2) discloses a retainer in which the axial position of a roller guide surface portion on one circumferential side surface of a pocket and the axial position of a roller guide surface portion on the other circumferential side surface of a pocket are different from each other. is disclosed.

JP 2004-144244 A Japanese Unexamined Patent Application Publication No. 2011-214702

In recent years, in order to reduce torque loss, the viscosity of lubricating oil has been reduced and the amount of lubricating oil has been reduced. In addition, in the case of a planetary gear bearing (planetary bearing) used in a planetary speed reduction mechanism, the planetary gear revolves while rotating, so a centrifugal force is applied to the retainer. Therefore, strength of the retainer is especially required.

If the pocket shape of the cage of the needle roller bearing used in the planetary gear is, for example, the shape disclosed in Patent Document 2 (a shape without recessed portions in the corners), the maximum stress is generated at the corners of the pocket. Analysis revealed that Therefore, in order to apply it to planetary gears, it is necessary to relieve the stress on the pocket corners.

In Patent Document 1, grooves are formed at the corners of the pocket to improve lubricity, but the grooves are formed beyond the axial range of the pocket. In this case, since the width of the annular portion of the retainer is narrow at the portion of the groove, there is concern that the annular portion may be insufficient in strength.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems described above, and an object of the present invention is to provide an optimal cage and needle rollers with cage for planetary gears.

A retainer according to one aspect of the present invention includes a pair of annular portions, a plurality of pillars extending in the axial direction and connecting the pair of annular portions, and a needle roller formed between the pillars adjacent in the circumferential direction. and a pocket in which the The needle roller has a pair of flat surfaces forming both end faces in the axial direction, and corners that intersect the flat surfaces and are chamfered in an arc shape with a radius of r1. The retainers are provided at four corners of the pocket within the axial range of the pocket, and are provided on the inner surface of the annular portion facing the pocket and the circular recess having a radius r2 larger than r1. , and a projection contacting the flat surface of the needle roller, and the projection dimension of the projection is determined according to the difference between the radius r1 and the radius r2.

Preferably, the convex portion is formed in a spherical shape. As a result, the contact area between the needle roller and the flat surface is reduced (point contact), so that the needle roller can rotate smoothly.

Moreover, it is desirable that the convex portion is provided so as to be in contact with the central portion of the flat surface of the needle roller. Thereby, heat generation due to friction between the flat surface of the needle roller and the convex portion can be suppressed.

An inner diameter side roller stop portion and an outer diameter side roller stop portion are provided on each of the first pocket surface and the second pocket surface of the column facing the pocket. It is desirable that the axial position of the radially outer roller stop portion of the first pocket surface and the axial position of the radially outer roller stop portion of the second pocket surface are different from each other. As a result, it is possible to prevent the oil film from running out due to the outer diameter side roller stop portion.

As one embodiment, the outer diameter side roller stop portion of the first pocket surface is configured by a single projection provided in the axial center portion, and the outer diameter side roller stop portion of the second pocket surface is formed at both ends in the axial direction. It consists of two projections provided on each part.

A needle roller with retainer according to another aspect of the present invention includes the retainer described above and needle rollers housed in pockets of the retainer.

According to the present invention, it is possible to suppress stress concentration on the corners of the pocket while ensuring the strength of the annular portion. Therefore, according to the present invention, it is possible to provide the optimum cage and needle roller with cage for planetary gears.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing a planetary speed reduction mechanism using needle rollers with a retainer according to an embodiment of the present invention, wherein (A) is a schematic diagram of the planetary speed reduction mechanism and (B) is a planetary gear. It is a cross-sectional view. 1 is a perspective view showing a retainer according to an embodiment of the invention; FIG. It is a side view showing a retainer concerning an embodiment of the invention. FIG. 4 is a partial cross-sectional view of the retainer viewed from the IV-IV direction of FIG. 3; FIG. 4 is a partial cross-sectional view of the retainer viewed from the VV direction of FIG. 3; FIG. 4 is an enlarged view of axial end portions of pockets in the retainer according to the embodiment of the present invention; (A) and (B) are diagrams schematically showing the relationship between a recessed portion and a convex portion. FIG. 10 is an enlarged view of the axial end of the pocket in the retainer with no projections;

An embodiment of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

(Overview of planetary speed reduction mechanism)
First, with reference to FIGS. 1(A) and 1(B), an outline of a planetary reduction mechanism 100 using a needle roller with cage 1 according to the present embodiment will be described. Referring to FIG. 1A, a planetary speed reduction mechanism 100 includes an internal gear (ring gear) 101 having internal teeth and surrounding the outer periphery, and a sun gear having external teeth and arranged at the center of the internal gear 101. (sun gear) 102 and a plurality of planetary gears (pinion gears) 103 having external teeth and arranged between the internal gear 101 and the sun gear 102 .

Each planetary gear 103 meshes with one internal gear 101 and one sun gear 102 . A shaft-shaped pinion shaft 105 is passed through the center hole of each planetary gear 103 . A hole wall surface of the central hole constitutes an inner peripheral surface of the planetary gear 103 . In an annular space defined by the inner peripheral surface of the planetary gear 103 and the outer peripheral surface of the pinion shaft 105, the needle roller 1 with retainer is arranged.

With particular reference to FIG. 1B, the end of each pinion shaft 105 is fixed to a common carrier 104 via washers 106 . A plurality of planetary gears 103 are thereby supported by one carrier 104 . Each planetary gear 103 is rotatably supported by the needle rollers 1 with retainer.

For example, when the sun gear 102 rotates clockwise while the internal gear 101 remains stationary, each planetary gear 103 rotates counterclockwise and the sun gear 102 The outer circumference revolves clockwise, and the carrier rotates clockwise.

The planetary speed reduction mechanism 100 is used, for example, in automatic transmissions of automobiles, which are becoming increasingly multi-stage. Needle rollers 1 with cage are used to support the planetary gear 103 in the planetary speed reduction mechanism 100 so as to be able to revolve and rotate.

Needle roller 1 with retainer has the outer peripheral surface of pinion shaft 105 as an inner raceway surface, and the inner peripheral surface of planetary gear 103 as an outer raceway surface. Needle roller 1 with cage is lubricated with lubricating oil supplied from the radially inner side toward the radially outer side through a lubricating oil passage provided in pinion shaft 105, for example.

(Structure of Needle Roller with Cage)
As shown in FIG. 1(B), the retainer-equipped needle roller 1 includes a plurality of needle rollers 2 and a retainer 3 that rotatably retains the plurality of needle rollers 2 . The needle roller 2 material is typically high carbon chromium bearing steel. The retainer 3 is made of resin, and is preferably made of a material containing a polyamide 9T resin and a fibrous filler from the viewpoint of improving strength.

The end face shape of needle roller 2 in the present embodiment is flat. That is, the needle roller 2 has a pair of flat surfaces 21 located at both ends in the axial direction. Such a needle roller 2 can have a longer straight portion (shaft portion) (longer effective length) than a needle roller having a round (spherical) end face shape, so that the contact surface pressure is reduced and planetary Suitable for gear 103.

A configuration example of the retainer 3 will be described with further reference to FIGS. 2 and 3. FIG. 2 and 3 are a perspective view and a side view, respectively, showing retainer 3 according to this embodiment. In the following description, the direction along the central axis C1 of the retainer 3 will be referred to as the "axial direction," the direction perpendicular to the central axis C1 as the "radial direction," and the circumferential direction around the central axis C1 as the "circumferential direction." It says.

Cage 3 has a plurality of pockets 40 that hold needle rollers 2 . The retainer 3 is of a cage type and has a pair of annular portions 30 located at both axial ends of the pocket 40 and a plurality of pillars 31 connecting the pair of annular portions 30 to each other. The column portion 31 extends along the axial direction of the retainer 3 and is coupled to the pair of annular portions 30 at both end portions 32 , 32 thereof. The columnar portion 31 has a constant thickness and extends linearly along the axial direction. The cross-sectional shape of the column portion 31 when the column portion 31 is cut along the radial direction is a trapezoidal shape in which the outer diameter side is larger than the inner diameter side.

The pocket 40 is defined between the pillars 31, 31 adjacent in the circumferential direction. Specifically, the pocket 40 includes pocket surfaces 33a and 33b formed on the adjacent column portions 31 and 31 and facing each other in the circumferential direction, and inner sides formed on the pair of annular portions 30 and facing each other in the axial direction. It is bounded by end faces 34a, 34b and four corners 35 located at the intersections of pocket faces 33a, 33b and inner end faces 34a, 34b. The shape of the pocket 40 is substantially rectangular when viewed from the outer diameter side of the retainer 3, but recessed portions 61 are provided at the four corners 35, as will be described later.

Each pocket surface 33a, 33b extends from one end portion 32 of the column portion 31 to the other end portion 32 and faces the rolling surface of the needle roller 2 (the outer peripheral surface of the straight portion). Each inner end surface 34a, 34b faces the flat surface 21 (FIG. 1(B)) that is both end surfaces of the needle roller 2. As shown in FIG. A distance L1 between the facing inner end faces 34a, 34b is greater than the total length of the needle roller 2, and a distance L2 between the facing pocket surfaces 33a, 33b is greater than the needle roller 2 diameter. The interval L1 corresponds to the axial length of the pocket 40 (the interval in the longitudinal direction), and the interval L2 corresponds to the interval in the lateral direction of the pocket 40 (the circumferential direction of the retainer 3).

(Example of configuration and arrangement of roller stoppers)
The pocket surfaces 33a and 33b of the retainer 3 are provided with roller stop portions 51 to 54 for restricting radial movement of the needle rollers 2. As shown in FIG. Specific configuration and arrangement examples of the roller stop portions 51 to 54 will be described with further reference to FIGS. 4 and 5. FIG. FIG. 4 is a partial cross-sectional view of the retainer 3 seen from the IV-IV direction of FIG. 3, showing one pocket surface 33a. FIG. 5 is a partial cross-sectional view of the retainer 3 viewed from the direction VV of FIG. 3, showing the other pocket surface 33b.

As shown in FIG. 4, roller stop portions 51 and 52 are provided on the inner diameter side and the outer diameter side of one pocket surface (hereinafter referred to as "first pocket surface") 33a, respectively. The roller stop portion 51 on the inner diameter side is composed of two protrusions 51a and 51b arranged symmetrically with respect to the axial centerline C2 of the retainer 3. As shown in FIG. The protrusions 51a and 51b are arranged at both ends of the first pocket surface 33a in the axial direction. The outer diameter side roller stop portion 52 is composed of one protrusion 52a arranged on the axial centerline C2.

The projections 51a and 51b on the inner diameter side and the projection 52a on the outer diameter side are arranged so that their axial positions do not overlap. The axial length of the inner diameter side roller stop portion 51, that is, the length obtained by adding the axial length L11 of the two projections 51a and 51b (dimension L11×2) is 25% of the axial length L1 of the pocket 40. % or more and 40% or less. Further, the axial length of the outer diameter side roller stop portion 52, that is, the axial dimension L12 of the projection 52a is preferably 20% or more and 30% or less of the axial length L1 of the pocket 40. FIG.

As shown in FIG. 5, roller stop portions 53 and 54 are provided on the inner diameter side and the outer diameter side of the other pocket surface (hereinafter referred to as "second pocket surface") 33b, respectively. The inner diameter side roller stop portion 53 is composed of two protrusions 53a and 53b arranged symmetrically about the axial center line C2. The protrusions 53a and 53b are arranged at both ends of the second pocket surface 33b in the axial direction. The outer diameter side roller stop portion 54 is also composed of two projections 54a and 54b arranged symmetrically about the axial centerline C2. Similarly, the projections 54a and 54b are arranged at both ends of the second pocket surface 33b in the axial direction.

Regarding the axial position, the projections 53a, 53b on the inner diameter side and the projections 54a, 54b on the outer diameter side are arranged so as to overlap each other. The axial dimension L21 of each of the projections 53a and 53b on the inner diameter side may be smaller than the axial dimension L22 of each of the projections 54a and 54b on the outer diameter side. , preferably the same as above. That is, the axial length of the inner diameter side roller stop portion 53, that is, the length obtained by adding the axial length L21 of the two projections 53a and 53b (dimension L21×2) is the axial length L1 of the pocket 40. is preferably 25% or more and 40% or less, and the axial length of the outer diameter side roller stop portion 54, that is, the length obtained by adding the axial dimension L22 of the two projections 54a and 54b (dimension L22 x 2) is preferably 20% or more and 30% or less of the axial length L1 of the pocket 40 .

As can be seen from the above numerical range, in the caged roller 1, the axial length of the roller stop portions 51 and 53 on the inner diameter side is greater than the axial length of the roller stop portions 52 and 54 on the outer diameter side. It may be longer than the length. As a result, it is possible to more reliably prevent the needle rollers 2 from falling off toward the inner diameter side.

4 and 5, the projections 51a and 51b on the inner diameter side of the first pocket surface 33a and the projections 53a and 53b on the inner diameter side of the second pocket surface 33b are arranged to face each other. It is That is, the axial positions of the protrusions 51a and 51b and the axial positions of the protrusions 53a and 53b completely overlap.

On the other hand, the projection 52a on the outer diameter side of the first pocket surface 33a and the projections 54a and 54b on the outer diameter side of the second pocket surface 33b do not face each other. That is, the axial position of the roller stopper portion 52 (projection 52a) on the outer diameter side of the first pocket surface 33a and the axial position of the roller stopper portion 54 (projections 54a, 54b) on the outer diameter side of the second pocket surface 33b are different from each other without overlapping.

In the present embodiment, the inner diameter side roller stop portions 51 and 53 have the same structure, but the invention is not limited to such an example. The number of protrusions of 51 and 53 may be varied, or the axial positions of the protrusions may be varied.

In addition, although the number of projections of the roller stop portions 52 and 54 on the outer diameter side is different (one for one and two for the other), the same number may be used if the axial positions are different. , and the number thereof is not limited.

(Pocket edge shape)
As shown in FIG. 2, retainer 3 according to the present embodiment is provided with relatively large relief portions 61 at four corners 35 of pocket 40 . In addition, convex portions 62 are provided on the inner end surfaces 34 a and 34 b of the pocket 40 .

FIG. 6 is an enlarged view of the axial end of the pocket 40 of the retainer 3. As shown in FIG. FIG. 6 shows the axial ends of the needle rollers 2 accommodated in the pockets 40 .

The needle roller 2 of the present embodiment has a pair of flat surfaces 21 forming both end surfaces in the axial direction, and corners 22 that intersect the flat surfaces 21 and are chamfered in an arc shape. The chamfering R of the corner 22 is, for example, 0.1 to 0.3 mm, for example 0.2 mm. The chamfering R (radius of the arc) of the corner portion 22 is hereinafter referred to as "radius r1". The center of the arc of the corner portion 22 is equidistant from the flat surface 21 and the outer peripheral surface 20 of the straight portion.

The relief portion 61 is formed in an arc shape with a radius of r2. The recessed portion 61 cuts out the end portion 32 of the column portion 31 in the same shape along the thickness direction. The radius r2 of the relief portion 61 is larger than the chamfer R (radius r1) of the needle roller 2 . The relief portion 61 is provided within the axial range of the pocket 40 (the range of the axial length L1 shown in FIG. 3). That is, it is provided without protruding to the annular portion 30 side. Therefore, the width of the portion of the annular portion 30 adjacent to the pocket 40 is greater than or equal to the specified dimension W. As shown in FIG.

Here, referring to FIG. 8, when the inner end surface 34b (and 34a) of the pocket 40 is not provided with the convex portion 62, the corner portion 22 of the needle roller 2 is recessed as schematically shown by hatching. It interferes with the part 61. On the other hand, in the present embodiment, since the convex portion 62 is provided on the inner end surface 34b (and 34a) of the pocket 40, the corner portion 22 of the needle roller 2 does not interfere with the relief portion 61. FIG. In other words, the convex portion 62 is provided so that the corner portion 22 of the needle roller 2 does not interfere with the relief portion 61 .

The protrusion 62 is provided at the center of the inner end surface 34b. The convex portion 62 protrudes spherically from the inner end surface 34b toward the axial center of the pocket 40 (toward the center line C2). In this case, the tip of the projection 62 (the apex of the sphere) is positioned on the circumferential centerline C3 of the pocket 40 when viewed from the radially outer side. As a result, the tip of the convex portion 62 comes into contact with the central portion of the flat surface 21 of the needle roller 2 . Since the central portion of the flat surface 21 of the needle roller 2 has a lower peripheral speed than the outer peripheral portion, heat generation due to friction between the flat surface 21 of the needle roller 2 and the convex portion 62 can be suppressed.

The protrusion height H of the convex portion 62 is determined according to the size of the relief portion 61 . That is, it is determined according to the difference between the chamfer R (radius r1) of the corner portion 22 of the needle roller 2 and the arc radius r2 of the relief portion 61 (hereinafter referred to as "radius difference").

Table 1 below shows the relationship between the radius difference (r2-r1) and the projection height H of the projection 62. The projection height H in the present embodiment represents the axial dimension from the inner end surface 34b (34a) of the pocket 40 to the tip of the projection 62 (apex of the sphere).

In Table 1, the case where the radius difference is 0 is described as a comparative example. In this case, the radius r2 of the relief portion 61 is equal to the chamfering R of the corner portion 22 of the needle roller 2, and interference as shown in FIG. 8 does not occur. Therefore, although it is possible in terms of design, it is not desirable from the viewpoint of mitigation of stress concentration on the corner 35 .

In this embodiment, as shown in Examples 1 to 4 in Table 1, the radius difference is determined to be greater than 0, that is, r2>r1. The radius difference in Example 1 corresponds to 1/2 of the chamfer R of the needle roller 2 , and the radius difference in Example 2 is equal to the chamfer R of the needle roller 2 . The radius difference in Example 3 corresponds to 3/2 of the chamfer R of the needle roller 2 , and the radius difference in Example 4 is twice the chamfer R of the needle roller 2 .

The protrusion height H of the protrusion 62 is designed to be higher as the radius difference is larger. FIG. 7A schematically shows the relationship between the relief portion 61a and the projection 62b in the first embodiment, and FIG. 7B shows the relief portion 61a and the projection in the fourth embodiment. A relationship with the portion 62b is schematically shown.

It is envisioned that a radius difference of 0.1-0.4 mm is used, as shown in Examples 1-4. Expressing the difference in radius with respect to the chamfer R of the needle roller 2, the difference in radius may be, for example, within the range of 1/2 to 2 times the chamfer R of the needle roller 2. The shape of the projection 62 is preferably spherical as shown, and the tip of the projection 62 is desirably rounded, but the tip of the projection 62 may be flat.

As described above, the retainer 3 of the present embodiment includes the relief portions 61 provided at the four corner portions 35 of the pocket 40 and the inner end surfaces 34a and 34b provided at the inner end surfaces 34a and 34b of the annular portion 30. and a convex portion 62 . As a result, a radially penetrating gap (lubricating oil flow path) can be secured between the needle roller 2 and the annular portion 30 , so that the oil permeability in the pocket 40 can be improved.

Further, the roller stop portions 52 and 54 on the outer diameter side of the first and second pocket surfaces 33a and 33b of the pocket 40 are provided so as not to face each other so as to shift their axial positions. A roller stop portion 52 on the outer diameter side of one pocket surface 3a is provided in the axially central portion. Therefore, in the roller stop portion 52 on the outer diameter side, it is possible to suppress oil film breakage around the joint between the straight portion of the needle roller 2 and the chamfer R(r1) of the corner portion 22, where peeling is likely to occur. The lubricating performance of the outer peripheral surface of the shaped roller 2 can be improved.

Also, the arc radius r2 of the relief portion 61 is made larger than the chamfering R of the corner portion 22 of the needle roller 2, and the corner portion 22 of the needle roller 2 and the corner portion 35 of the pocket 40 do not interfere ( The projection dimension of the convex portion 62 is determined according to the radius difference so that a gap is generated. Therefore, stress concentration on the corner 35 of the pocket 40 can be alleviated during use.

Further, since the relief portion 61 is provided (only) within the axial range of the pocket, the strength of the annular portion 30 of the retainer 3 can be ensured. Therefore, the caged roller 1 of the present embodiment is suitable for the planetary gear 103 that revolves while rotating.

Needle roller 1 with cage according to the present embodiment is used together with a shaft (pinion shaft 105 in FIG. 1) that is inserted through the center hole of cage 3 and constitutes the inner raceway surface of needle roller 2 to form a planetary gear. It can also be provided as a needle roller bearing for 103.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and range of equivalents of the scope of the claims.

1 Needle Roller with Cage 2 Needle Roller 3 Cage 21 Flat Surface 22 Corner 30 Annular Part 31 Column 33a, 33b Pocket Surface 34a, 34b Inner End Face 35 Corner 40 Pocket 51, 52, 53, 54 Roller Stopper 51a, 51b, 52a, 53a, 53b, 54a, 54b Projection 61, 61a, 61b Relief Part 62, 62a, 62b Protrusion 100 Planetary Reduction Mechanism 101 internal gear, 102 sun gear, 103 planetary gear, 105 pinion shaft, r1, r2 radius.

Claims (6)

A pair of annular portions, a plurality of pillars extending in the axial direction and connecting the pair of annular portions, and pockets formed between the pillars adjacent in the circumferential direction and accommodating needle rollers a retainer,
The needle roller has a pair of flat surfaces forming both end faces in the axial direction, and corners that intersect the flat surfaces and are chamfered in an arc shape with a radius of r1,
arc-shaped relief portions provided at four corners of the pocket within the axial range of the pocket and having a radius r2 larger than the r1;
a convex portion provided on the inner surface of the annular portion facing the pocket and in contact with the flat surface of the needle roller;
The retainer, wherein the projecting dimension of the convex portion is determined according to the difference between the radius r1 and the radius r2. 2. The retainer according to claim 1, wherein said convex portion is formed in a spherical shape. 3. The retainer according to claim 1, wherein said convex portion is provided so as to contact a central portion of said flat surface of said needle roller. A first pocket surface and a second pocket surface of the column facing the pocket are provided with an inner diameter side roller stop portion and an outer diameter side roller stop portion,
The axial position of the outer diameter side roller stop portion of the first pocket surface and the axial position of the outer diameter side roller stop portion of the second pocket surface are different from each other. A retainer according to any one of the preceding claims. The outer diameter side roller stop portion of the first pocket surface is configured by one projection provided in the axial center portion, and the outer diameter side roller stop portion of the second pocket surface is formed at both axial end portions. 5. A retainer according to claim 4, constituted by two protrusions each provided. a retainer according to any one of claims 1 to 5;
needle rollers with a retainer, comprising the needle rollers housed in the pockets of the retainer.

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