Cage-equipped needle roller

Abstract

To provide a cage-equipped needle roller which achieves excellent durability while in use in which a centrifugal force generated by revolving motion occurs in the needle roller.SOLUTION: A base R section 20 is formed on an axial inner side of a base of a roller stopper piece 10. An inner diameter-side R section 19 is formed at a portion where a radial inner-side surface 17 of a pillar-inclined part 8 and a radial inner-side surface 18 of a pillar edge section 7 intersect. The base R section 20 is formed at a position offset axially outward from the inner diameter-side R section 19 such that an axial range of the base R section 20 and an axial range of the inner diameter-side R section 19 do not overlap.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] This invention relates to a needled roller with a cage and a revolving mechanism using the needled roller with a cage.

Background Art

[0002] As a needled roller with a cage for supporting a planetary gear of a planetary gear mechanism, the applicant of the present application has already proposed the one described in Patent Document 1.

[0003] A planetary gear mechanism includes an external gear sun gear, an internal gear ring gear formed in an annular shape surrounding the sun gear, a plurality of planetary gears incorporated between the outer periphery of the sun gear and the inner periphery of the ring gear so as to mesh with both the sun gear and the ring gear, and a planetary carrier that rotatably and revolvably supports the plurality of planetary gears.

[0004] The planetary carrier has a carrier body that revolves at a fixed position and a plurality of planetary shafts attached at positions radially away from the revolution center of the carrier body. The planetary shafts are fixed to the carrier body so as to revolve integrally with the carrier body. A planetary gear is rotatably attached to the outer periphery of the planetary shaft via a needled roller with a cage.

[0005] Here, the needled roller with a cage for supporting the planetary gear has a plurality of needled rollers arranged at intervals in the circumferential direction and a cage that holds the plurality of needled rollers. The cage has a pair of annular portions facing each other in the axial direction with the plurality of needled rollers therebetween, and a plurality of column portions that connect the pair of annular portions passing between the circumferentially adjacent needled rollers. The pair of annular portions and the circumferentially adjacent column portions form a pocket for accommodating the needled rollers.

[0006] In this planetary gear mechanism, when rotation is input to the sun gear, the planetary gears revolve integrally with the planetary carrier while rotating on their own axes. At this time, unlike the general needle rollers with a cage that rotate at a fixed position, centrifugal force due to the revolving motion is generated in each of the needle rollers of the needle roller with a cage that supports the planetary gears. Then, due to the centrifugal force generated in the needle rollers by this revolving motion, each column portion of the cage is loaded so as to alternately repeat a state of being pressed by the needle rollers located on one side in the circumferential direction with respect to the column portion and a state of being pressed by the needle rollers located on the other side in the circumferential direction with respect to the column portion. Therefore, tensile stress and compressive stress repeatedly act on the corner portions of the pockets that accommodate the needle rollers, and the cage is likely to undergo fatigue failure.

[0007] Therefore, in Patent Document 1, in order to prevent fatigue failure of the cage, an arcuate corner R portion (fillet portion) is formed at the corner portion of the pocket that accommodates the needle rollers when viewed from the radial direction, and by setting the radius of curvature of the corner R portion to be large, stress concentration at the corner portion of the pocket is alleviated.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] The inventors of the present application considered further improving the durability of the cage for the needle roller with a cage that supports the planetary gears of the planetary gear mechanism as in Patent Document 1. As a result, in the cage of Patent Document 1, there are two locations other than the corner portion of the pocket that accommodates the needle rollers where there is a possibility that high stress may be generated in the cage due to the centrifugal force generated in the needle rollers by the revolving motion acting on the column portion of the cage, and due to the proximity of the positions of these two locations, the stress becomes high, and it was noticed that fatigue failure of the cage is likely to occur.

[0010] That is, in the cage of the needle roller with cage of Patent Document 1, each column portion has a pair of column end portions extending axially inward from a pair of annular portions with a constant outer diameter, a pair of column inclined portions extending obliquely so that the outer diameter gradually decreases toward the axially inner side from the pair of column end portions, and a column central portion connecting the pair of column inclined portions. On the column end portion, a rolling element stopper piece protruding in the circumferential direction is formed so as to restrict the outward movement of the needle roller in the radial direction.

[0011] In the cage having this configuration, when centrifugal force due to the revolution movement is generated in the needle roller and the needle roller presses the column portion of the cage by the centrifugal force, a moment load is generated on the column portion such that the needle roller presses the column central portion (or the column inclined portion) in the circumferential direction of the cage and twists the column inclined portion around the column end portion. Then, due to the moment load, high stress is generated at the portion where the radially inner surface of the column inclined portion intersects the radially inner surface of the column end portion, and at the axially inner portion of the base of the rolling element stopper piece protruding in the circumferential direction from the column end portion.

[0012] Here, in a conventional needle roller with cage such as that of Patent Document 1, the axially inner portion of the base of the rolling element stopper piece and the portion where the radially inner surface of the column inclined portion intersects the radially inner surface of the column end portion are in a close positional relationship. Therefore, when a moment load that twists the column inclined portion around the column end portion is generated by the needle roller pressing the column portion of the cage, the high stress generated at the axially inner portion of the base of the rolling element stopper piece and the high stress generated at the portion where the radially inner surface of the column inclined portion intersects the radially inner surface of the column end portion overlap, and it has been noticed that fatigue failure of the cage is likely to occur.

[0013] In addition, in the needle roller with cage of Patent Document 1, an arcuate root R portion is formed on the axially inner portion of the base of the rolling element stopper piece protruding in the circumferential direction from the column end portion, and this root R portion alleviates the stress concentration at the axially inner portion of the base of the rolling element stopper piece. However, since the root R portion and the portion where the radially inner surface of the column inclined portion intersects the radially inner surface of the column end portion are in a close positional relationship, ultimately, the above problem cannot be fundamentally solved.

[0014] The problem to be solved by this invention is to provide a needled roller with a cage having excellent durability when used in applications where centrifugal force generated by revolution motion is generated in the needled rollers.

Means for Solving the Problem

[0015] To solve the above problems, this invention provides a needled roller with a cage having the following configuration. [Configuration 1] A plurality of needled rollers arranged at intervals in the circumferential direction, and a cage that holds the plurality of needled rollers, and the cage has a pair of annular portions facing each other in the axial direction with the plurality of needled rollers therebetween, and a plurality of column portions that connect the pair of annular portions through between the needled rollers adjacent to each other in the circumferential direction, each column portion has a pair of column end portions extending axially inward from the pair of annular portions with a constant outer diameter, a pair of column inclined portions extending inclinedly so that the outer diameter gradually decreases as it goes axially inward from the pair of column end portions, and a column central portion that connects the pair of column inclined portions, in the needled roller with a cage in which a roller stopper piece protruding in the circumferential direction is formed at the column end portion so as to regulate the outward movement of the needled roller in the radial direction, an arc-shaped root R portion is formed on the inner side in the axial direction of the root of the roller stopper piece when viewed in the radial direction, an arc-shaped inner diameter side R portion is formed at a portion where the radially inner side surface of the column inclined portion and the radially inner side surface of the column end portion intersect when viewed in the circumferential direction, The needled roller with a cage is characterized in that the root R portion is formed axially outside the inner diameter side R portion so that the axially formed range where the root R portion is formed and the axially formed range where the inner diameter side R portion is formed do not overlap.

[0016] When this configuration is adopted, an arcuate root R portion is formed on the inner side in the axial direction at the root of the roller stopper piece protruding in the circumferential direction from the column end portion. Also, an inner diameter side R portion that is arcuate when viewed in the circumferential direction is formed at the portion where the inner side surface in the radial direction of the column inclined portion and the inner side surface in the radial direction of the column end portion intersect. Therefore, when a moment load that twists the column inclined portion around the column end portion is generated by the needle roller pressing the column portion of the cage, the stress concentration at the portion on the inner side in the axial direction at the root of the roller stopper piece (root R portion) is alleviated, and the stress concentration at the portion where the inner side surface in the radial direction of the column inclined portion and the inner side surface in the radial direction of the column end portion intersect (inner diameter side R portion) is also alleviated. Furthermore, the root R portion is formed at a position shifted axially outward from the inner diameter side R portion so that the axial range in which the root R portion is formed and the axial range in which the inner diameter side R portion is formed do not overlap. Therefore, when a moment load that twists the column inclined portion around the column end portion is generated by the needle roller pressing the column portion of the cage, it is possible to prevent the high stress generated at the portion on the inner side in the axial direction at the root of the roller stopper piece (root R portion) from overlapping with the high stress generated at the portion where the inner side surface in the radial direction of the column inclined portion and the inner side surface in the radial direction of the column end portion intersect (inner diameter side R portion), and the maximum stress can be suppressed low. Therefore, when used in an application where centrifugal force due to the revolving motion is generated in the needle roller, fatigue failure of the cage is less likely to occur, and it has excellent durability.

[0017] [Configuration 2] The needle roller with cage according to Configuration 1, wherein an end portion on the outer side in the axial direction of the roller stopper piece and the annular portion are connected via an arcuate corner R portion when viewed in the radial direction.

[0018] When this configuration is adopted, when a moment load that twists the column inclined portion around the column end portion is generated by the needle roller pressing the column portion of the cage, the stress concentration at the portion where the end portion on the outer side in the axial direction of the roller stopper piece and the annular portion are connected (corner R portion) can be alleviated.

[0019] [Configuration 3] The annular portion has a cylindrical outer peripheral surface, The column end portion has a partial cylindrical outer side surface in the radial direction having the same outer diameter as the outer peripheral surface of the annular portion, The roller stopper piece has a partial cylindrical radially outer surface continuously formed on the radially outer surface of the column end portion. The needle roller with cage according to Configuration 1 or 2, wherein an outer peripheral surface of the annular portion, a radially outer surface of the column end portion, and a radially outer surface of the roller stopper piece are defined as a guided surface of the cage.

[0020] When this configuration is adopted, the cage becomes an outer diameter guiding type.

[0021] [Configuration 4] The needle roller with cage according to any one of Configurations 1 to 3, wherein each of the annular portions has a welded portion joined in the circumferential direction by welding.

[0022] When this configuration is adopted, the cage becomes a welded cage. In this case, since the strip steel is bent into a ring shape and both ends of the strip steel are welded to manufacture the cage, the manufacturing cost of the cage can be kept low.

[0023] [Configuration 5] Each of the annular portions has a cylindrical portion and an inward flange portion extending radially inward from an axially outer end of the cylindrical portion. The needle roller with cage according to Configuration 4, wherein a radial thickness of a central portion of the column is 0.5 mm to 1.5 mm.

[0024] When this configuration is adopted, the cage becomes an M-shaped cage. In this case, when the radial thickness of the central portion of the column is set to 0.5 mm or more, the strength of the cage can be ensured, and when the radial thickness of the central portion of the column is set to 1.5 mm or less, when manufacturing the cage, it is easy to bend the strip steel, which is a material of the cage, into a ring shape, and it is easy to ensure the dimensional accuracy of the cage.

[0025] Further, in the present invention, as a revolving mechanism using the above-described needle roller with cage, the following configurations are also provided. [Configuration 6] A revolving member that revolves at a fixed position, A planetary shaft that is arranged at a position radially away from a revolving center of the revolving member and revolves integrally with the revolving member, A revolving mechanism having a rotating member rotatably attached to the outer periphery of the planetary shaft via a needled roller with a cage according to any one of Configurations 1 to 5.

Advantages of the Invention

[0026] In the needled roller with a cage of this invention, since the root R portion is formed at a position axially offset outward from the inner diameter side R portion so that the axially formed range of the root R portion and the axially formed range of the inner diameter side R portion do not overlap, when a moment load that twists the column inclination portion around the column end portion is generated by the needled roller pressing the column portion of the cage, it is possible to prevent the high stress generated in the portion axially inside the root of the anti-rolling piece (root R portion) from overlapping with the high stress generated at the portion where the radially inner surface of the column inclination portion intersects the radially inner surface of the column end portion (inner diameter side R portion), and the maximum stress can be kept low. Therefore, when used in applications where centrifugal force due to revolving motion is generated in the needled roller, fatigue failure of the cage is less likely to occur, and it has excellent durability.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0028] Figures 1 and 2 show the needle roller 1 with a cage according to an embodiment of the present invention. The needle roller 1 with a cage has a plurality of needle rollers 2 and a cage 3 that holds the plurality of needle rollers 2.

[0029] The needle roller 2 is a roller having a cylindrical outer periphery. Each needle roller 2 is arranged at intervals in the circumferential direction in a posture where the axis of the needle roller 2 is parallel to the axis of the cage 3. The diameter of the needle roller 2 is 6 mm or less, and the axial length of the needle roller 2 is 3 times or more and 10 times or less the diameter of the needle roller 2. Clawing (making the generatrix shape of the outer periphery of the needle roller 2 a convex curve with a slight curvature) may be applied to the outer periphery of the needle roller 2 to prevent stress concentration from occurring on the outer periphery of the end of the needle roller 2 due to mounting errors or the like.

[0030] The cage 3 has a pair of annular portions 4 that face each other in the axial direction with a plurality of needle rollers 2 therebetween, and a plurality of column portions 5 that connect the pair of annular portions 4 through between the circumferentially adjacent needle rollers 2. The pair of annular portions 4 and the column portions 5 adjacent to each other in the circumferential direction form a pocket 6 for accommodating the needle rollers 2.

[0031] As shown in FIGS. 1 and 3, the column portion 5 has a pair of column end portions 7 that extend axially inward from the pair of annular portions 4 with a constant outer diameter, a pair of column inclined portions 8 that extend obliquely so that the outer diameter gradually decreases as they extend axially inward from the pair of column end portions 7, and a column central portion 9 that connects the pair of column inclined portions 8. Axially inward is the direction from the annular portion 4 toward the column portion 5, and axially outward is the direction from the column portion 5 toward the annular portion 4.

[0032] As shown in FIG. 3, the outer diameter D2 of the column central portion 9 is smaller than the outer diameter D1 of the column end portion 7. Also, the inner diameter of the column end portion 7 is larger than the diameter of the circle connecting the centers of the respective needle rollers 2 (pitch circle diameter of the needle rollers 2). The radial thickness t of the column central portion 9 is set in the range of 0.5 mm to 1.5 mm. As shown in FIG. 2, the column central portion 9 has a circumferential width larger than the circumferential width of the column inclined portion 8, and by guiding the needle rollers 2 at both circumferential ends of the column central portion 9, the circumferential interval of the needle rollers 2 is maintained.

[0033] As shown in Fig. 6, a roller stop piece 10 protruding in the circumferential direction is formed at the column end 7. As shown in Fig. 2, the roller stop piece 10 is formed to extend in the circumferential direction on the radially outer side of the diameter of the circle connecting the centers of the respective needle rollers 2 (pitch circle diameter of the needle rollers 2) so as to regulate the outward movement of the needle rollers 2 in the radial direction and prevent the needle rollers 2 from falling off radially outward from the pocket 6.

[0034] As shown in Fig. 3, one of the pair of annular portions 4 extends in the circumferential direction along one end surface of both end surfaces of the plurality of needle rollers 2, and the other annular portion 4 extends in the circumferential direction along the other end surface of the plurality of needle rollers 2. Each annular portion 4 has a cylindrical portion 11 and an inward flange portion 12 extending radially inward from the axially outer end of the cylindrical portion 11. As shown in Fig. 1, each annular portion 4 has a welded portion 13 joined in the circumferential direction by welding.

[0035] As shown in Fig. 6, the annular portion 4 has a cylindrical outer peripheral surface 14. The column end 7 has a partial cylindrical radially outer surface 15 having the same outer diameter as the outer peripheral surface 14 of the annular portion 4. The roller stop piece 10 has a partial cylindrical radially outer surface 16 formed continuously in the circumferential direction on the radially outer surface 15 of the column end 7. The outer peripheral surface 14 of the annular portion 4, the radially outer surface 15 of the column end 7, and the radially outer surface 16 of the roller stop piece 10 are guided surfaces guided by the inner circumference of a member (such as the planetary gear 31 in Fig. 8) attached to the radially outer side of the needle roller bearing 1. The guided surface is a ground finish surface having a surface roughness of Ra 1.0 μm or less.

[0036] As shown in Fig. 4, an inner diameter side R portion 19 is formed at a portion where the radially inner surface 17 of the column inclined portion 8 and the radially inner surface 18 of the column end portion 7 intersect. The inner diameter side R portion 19 has a shape curved in a concave arc shape when viewed from the circumferential direction. Also, a root R portion 20 is formed on the axially inner side (right side in the figure) of the base of the roller stop piece 10. The root R portion 20 has a shape curved in a concave arc shape when viewed from the radial direction, and smoothly connects between the axially inner surface 21 of the roller stop piece 10 and the circumferential end surface 22 of the column end portion 7. The radius of curvature of the root R portion 20 is set to be 1 / 4 or more (preferably 1 / 3 or more) of the circumferential length of the roller stop piece 10. Also, the end portion on the axially outer side (left side in the figure) of the roller stop piece 10 and the annular portion 4 are connected via an arc-shaped corner R portion 23 when viewed from the radial direction.

[0037] The root R portion 20 is formed at a position shifted axially outward (left side in the figure) from the inner diameter side R portion 19 so that the axially formed range of the root R portion 20 and the axially formed range of the inner diameter side R portion 19 do not overlap. That is, with the axially end surface of the pocket 6 as the reference point O, when measuring the axial distance L1 from the reference point O to the start position of the root R portion 20 and the axial distance L2 from the reference point O to the start position of the inner diameter side R portion 19, the positional relationship between the root R portion 20 and the inner diameter side R portion 19 is set such that the axial distance L1 is smaller than the axial distance L2.

[0038] Here, when measuring the axial distance L1, as shown in Fig. 5, assume a straight line in contact with the root R portion 20 (a straight line along the circumferential end surface 22 of the column end portion 7), and set the start position S of the root R portion 20 at a position 10 μm away from that straight line in the circumferential direction. In the figure, for clarity, the 10 μm distance is exaggeratedly shown, but the actual 10 μm is extremely smaller than the distance shown in the figure. Similarly, when measuring the axial distance L2, assume a straight line in contact with the inner diameter side R portion 19 (a straight line along the radially inner surface 18 of the column end portion 7), and set the start position of the inner diameter side R portion 19 at a position 10 μm away from that straight line in the radially inner direction.

[0039] As shown in Fig. 2, the rolling stop piece 10 has a radially inner surface 24 that extends circumferentially and is continuously formed on the radially inner surface 18 of the column end portion 7, and a rolling stop surface 25 that inclines radially outward in the circumferential direction from the radially inner surface 24.

[0040] This cage 3 can be manufactured as follows. That is, first, a flat strip-shaped steel strip is formed into an M-shaped cross-section (forming process), pockets 6 for accommodating the needle rollers 2 are formed in the steel strip with the M-shaped cross-section (pocket punching process), the steel strip with the pockets 6 formed is cut to a length corresponding to the circumferential length of the cage 3 (cutting process), the cut steel strip is bent into a cylindrical shape (bending process), both ends of the steel strip bent into a cylindrical shape are joined by welding (welding process), and then it can be manufactured by performing outer peripheral grinding, heat treatment, etc.

[0041] This needle roller 1 with a cage can be used as a needle roller with a cage that supports the planet gear 31 of the planetary gear mechanism 30 shown in Fig. 7. The planetary gear mechanism 30 is, for example, a part of a transmission that changes the rotation of a prime mover (engine, electric motor, etc.) for vehicle running.

[0042] The planetary gear mechanism 30 has an external gear sun gear 32, an internal gear ring gear 33 formed in an annular shape surrounding the sun gear 32, a plurality of planet gears 31 incorporated between the outer periphery of the sun gear 32 and the inner periphery of the ring gear 33 so as to mesh with both the sun gear 32 and the ring gear 33, and a planet carrier 34 that supports the plurality of planet gears 31 so as to be rotatable about its own axis and revolvable.

[0043] The planet carrier 34 has a carrier body 35 that revolves at a fixed position, and a plurality of planet shafts 36 attached at positions radially away from the revolution center of the carrier body 35. The planet shafts 36 are fixed to the carrier body 35 so as to revolve integrally with the carrier body 35. The planet gear 31 is rotatably attached to the outer periphery of the planet shaft 36 via the needle roller 1 with a cage.

[0044] As shown in FIG. 8, the needle roller 2 that constitutes the needle roller 1 with a cage rolls in contact with the outer periphery of the planet shaft 36 and the inner periphery of the planet gear 31. Further, the cage 3 that constitutes the needle roller 1 with a cage is positioned radially by being guided on the inner periphery of the planet gear 31.

[0045] In the planetary gear mechanism 30 shown in FIG. 7, when the rotation of a prime mover (not shown) is input to the sun gear 32, the planet gear 31 rotates while revolving integrally with the planet carrier 34. At this time, different from a general needle roller with a cage that rotates at a fixed position, a centrifugal force due to the revolving motion is generated in each needle roller 2 shown in FIG. 2. Then, due to the centrifugal force generated in the needle roller 2 by this revolving motion, each column portion 5 of the cage 3 is in a state of being pressed by the needle roller 2 located on one side in the circumferential direction with respect to the column portion 5 and a state of being pressed by the needle roller 2 located on the other side in the circumferential direction with respect to the column portion 5, and receives a load so as to alternately repeat these states. At this time, a moment load that twists the column inclined portion 8 around the column end portion 7 is generated in the column portion 5 when the needle roller 2 presses the center portion 9 of the column in the circumferential direction. Then, due to that moment load, high stress is generated at the portion where the radially inner surface 17 of the column inclined portion 8 shown in FIG. 4 intersects with the radially inner surface 18 of the column end portion 7, and at the portion axially inner of the base of the roller stopper piece 10 that protrudes in the circumferential direction from the column end portion 7.

[0046] Here, in a conventional needle roller with a cage, a positional relationship where the portion axially inner of the base of the roller stopper piece 10 and the portion where the radially inner surface 17 of the column inclined portion 8 intersects with the radially inner surface 18 of the column end portion 7 are close (a positional relationship where their axial positions are substantially the same) exists. Therefore, when a moment load that twists the column inclined portion 8 around the column end portion 7 is generated by the needle roller 2 pressing the column portion 5 of the cage 3, the high stress generated at the portion axially inner of the base of the roller stopper piece 10 and the high stress generated at the portion where the radially inner surface 17 of the column inclined portion 8 intersects with the radially inner surface 18 of the column end portion 7 overlap, and there is a problem that fatigue failure of the cage 3 is likely to occur.

[0047] In response to this problem, in the needle roller 1 with a cage of the above-described embodiment, as shown in FIG. 4, an arcuate base R portion 20 is formed on the inner side in the axial direction at the base of the anti-rotation piece 10 when viewed radially. Also, an inner-diameter side R portion 19 that is arcuate when viewed in the circumferential direction is formed at the portion where the radially inner surface 17 of the column inclination portion 8 and the radially inner surface 18 of the column end portion 7 intersect. Therefore, when the needle roller 2 presses against the column portion 5 of the cage 3 and a moment load that twists the column inclination portion 8 around the column end portion 7 is generated, stress concentration at the portion on the inner side in the axial direction at the base of the anti-rotation piece 10 (base R portion 20) is alleviated, and stress concentration at the portion where the radially inner surface 17 of the column inclination portion 8 and the radially inner surface 18 of the column end portion 7 intersect (inner-diameter side R portion 19) is also alleviated. Furthermore, the base R portion 20 is formed at a position shifted axially outward (left side in the figure) from the inner-diameter side R portion 19 so that the axially formed range of the base R portion 20 and the axially formed range of the inner-diameter side R portion 19 do not overlap. Therefore, when the needle roller 2 presses against the column portion 5 of the cage 3 and a moment load that twists the column inclination portion 8 around the column end portion 7 is generated, it is possible to prevent the high stress generated at the portion on the inner side in the axial direction at the base of the anti-rotation piece 10 (base R portion 20) from overlapping with the high stress generated at the portion where the radially inner surface 17 of the column inclination portion 8 and the radially inner surface 18 of the column end portion 7 intersect (inner-diameter side R portion 19), and the maximum stress can be suppressed to a low level. Therefore, as shown in FIGS. 7 and 8, when used in an application where centrifugal force due to the revolution motion is generated in the needle roller 2, fatigue failure of the cage 3 is less likely to occur, and it has excellent durability.

[0048] Also, as shown in FIG. 6, in this needle roller 1 with a cage, the end portion on the outer side in the axial direction (left side in the figure) of the anti-rotation piece 10 and the annular portion 4 are connected via an arcuate corner R portion 23 when viewed radially. Therefore, when the needle roller 2 presses against the column portion 5 of the cage 3 and a moment load that twists the column inclination portion 8 around the column end portion 7 is generated, it is possible to alleviate stress concentration at the portion where the end portion on the outer side in the axial direction of the anti-rotation piece 10 and the annular portion 4 are connected (corner R portion 23).

[0049] Furthermore, in this needle roller and cage assembly 1, the radial thickness t of the column center portion 9 shown in Figure 3 is set to 0.5 mm or more, which results in high strength of the cage 3. Furthermore, because the radial thickness t of the column center portion 9 is set to 1.5 mm or less, when manufacturing the cage 3, it is easy to bend the strip steel that is the material for the cage 3 into a ring shape, making it easy to ensure the dimensional precision of the cage 3.

[0050] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0051] 1 Needle roller and cage assembly 2 needle rollers 3 Cage 4 Annular section 5 Pillar part 7 Column end 8 Column slope 9 Pillar center 10 Roller stopper 11 Cylindrical part 12 Inward flange 13 Welding points 14 Outer surface 15 Radial outer surface 16 Radial outer surface 19 Inner diameter side R section 20 Base R 23 Corner R 30 Planetary gear mechanism (revolution mechanism) 31 Planetary gear (rotating member) 34 Planet carrier (revolving member) 36 Planetary shaft t Radial thickness

Claims

1. A plurality of needle rollers (2) arranged at intervals in the circumferential direction, and a cage (3) for holding the plurality of needle rollers (2), wherein the cage (3) has a pair of annular portions (4) facing each other in the axial direction with the plurality of needle rollers (2) therebetween, and a plurality of column portions (5) connecting the pair of annular portions (4) passing between the circumferentially adjacent needle rollers (2), each of the column portions (5) has a pair of column end portions (7) extending axially inward from the pair of annular portions (4) with a constant outer diameter, a pair of column inclined portions (8) extending obliquely so that the outer diameter gradually decreases toward the axially inward direction from the pair of column end portions (7), and a column central portion (9) connecting the pair of column inclined portions (8), in the needle roller with cage in which a roller stopper piece (10) protruding in the circumferential direction is formed on the column end portion (7) so as to restrict the radially outward movement of the needle roller (2), an arc-shaped root R portion (20) is formed on the axially inner side of the root of the roller stopper piece (10) when viewed in the radial direction, an arc-shaped inner diameter side R portion (19) is formed at the portion where the radially inner side surface (17) of the column inclined portion (8) and the radially inner side surface (18) of the column end portion (7) intersect when viewed in the circumferential direction, the needle roller with cage is characterized in that the root R portion (20) is formed axially outside the inner diameter side R portion (19) so that the axially formed range of the root R portion (20) and the axially formed range of the inner diameter side R portion (19) do not overlap.

2. The needle roller with cage according to claim 1, wherein an axially outer end portion of the roller stopper piece (10) and the annular portion (4) are connected via an arc-shaped corner R portion (23) when viewed in the radial direction.

3. The annular portion (4) has a cylindrical outer peripheral surface (14), the column end portion (7) has a partial cylindrical radially outer side surface (15) having the same outer diameter as the outer peripheral surface (14) of the annular portion (4), the roller stopper piece (10) has a partial cylindrical radially outer side surface (16) continuously formed on the radially outer side surface (15) of the column end portion (7), The needle roller with cage according to claim 1 or 2, wherein the outer peripheral surface (14) of the annular portion (4), the radially outer side surface (15) of the column end portion (7), and the radially outer side surface (16) of the roller stopper piece (10) are used as the guided surface of the cage (3).

4. The needle roller with cage according to claim 1 or 2, wherein each of the annular portions (4) has a welded portion (13) joined in the circumferential direction by welding.

5. Each of the annular portions (4) has a cylindrical portion (11) and an inward flange portion (12) extending radially inward from an axially outer end of the cylindrical portion (11). The needle roller with cage according to claim 4, wherein the radial thickness (t) of the central portion (9) of the column is 0.5 mm to 1.5 mm.

6. A revolving member (34) revolving at a fixed position, A planet shaft (36) disposed at a position radially away from the center of revolution of the revolving member (34) and revolving integrally with the revolving member (34), A revolving mechanism having a rotating member (31) rotatably attached to the outer periphery of the planet shaft (36) via the needle roller with cage (1) according to claim 1 or 2.

Images