JP2006200672A - Thrust roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce manufacturing cost, and to restrain rotational torque small. <P>SOLUTION: In this thrust roller bearing, a plurality of rollers 16 are rollingly arranged between raceway surfaces of both bearing rings 12 and 14, and a rollingly traveling surface of the rollers 16 is formed in a taper shape of substantially equalizing a rollingly traveling speed on the inner diameter side and the outer diameter side of the rollers 16, and both raceway surfaces are formed in a taper shape corresponding to the roller rollingly traveling surface. While forming outer diameter side end parts 12b and 14b continuing with the raceway surfaces of the bearing rings 12 and 14 as a collarless structure, the rollers 16 are held by a cage 18, and the axial cross-sectional area of an outer diameter side side plate 18b of the cage 18 is formed larger than the axial cross-sectional area of an inner diameter side side plate 18c. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thrust roller bearing, and more particularly, to a thrust roller bearing incorporated in mechanical equipment of various industries such as automobiles and machine tools.

  Thrust roller bearings are mainly bearings for thrust loads, and have various advantages such as high load capacity and high rigidity while being simple in structure and low in section height and space saving. It is a bearing provided. In such a thrust roller bearing, the rollers are arranged between the raceway surfaces of both bearing rings in a state of linear line contact with the bearing center axis, so the difference in the circumferential speed between the roller and the raceway surface is the difference between the rollers. Needle rollers that are maximum at both ends and have a longer roller length than the outer diameter of the roller have a greater tendency, and differential slip (roller skew) also increases. If differential slip occurs in the rolling motion, the torque will increase, and the oil film may be cut off, resulting in the possibility of seizure from metal contact.

On the other hand, in recent machines and devices, with a tendency to reduce friction, thrust roller bearings incorporated therein are also required to have a reduced rotational torque. Examples of such machines and devices include, for example, automobile air compressors and automatic transmissions. In order to reduce the increase in rotational torque due to such differential sliding of the rollers, as shown in FIG. 8, the rolling surface of the roller 16 is tapered, and the raceway surfaces of both race rings 12 and 14 are made into the roller 16. A thrust roller bearing having a tapered shape corresponding to the rolling surface is proposed (see Patent Document 1). In this thrust roller bearing, in order to prevent the roller 16 from being pushed out by the thrust load acting on the roller 16 and falling off, the outer side of the roller 16 is moved to the outer diameter side of the race rings 12 and 14. Since the flanges 12c and 14c that are in contact with the radial side end surface are provided, the shape of the races 12 and 14 is complicated, and the manufacturing cost is high.
JP 2002-89568 A

  Therefore, the problem to be solved by the present invention is to be able to suppress an increase in rotational torque due to differential sliding of the rollers with a structure that can be manufactured at low cost.

  The thrust roller bearing according to the present invention is a thrust roller bearing in which a plurality of rollers are arranged between the raceway surfaces of both race rings, and these rollers are rotatably held by a cage. In order to eliminate the difference in peripheral speed on the radial side, correspondingly, at least one of the raceway surfaces is tapered, and the outer diameter side end of the raceway is made wrinkled. The axial sectional area of the outer diameter side plate is made larger than the axial sectional area of the inner diameter side plate.

  According to the present invention, since the outer diameter side end portions of both race rings have a wrinkle-free structure, the race rings can be manufactured at low cost. In addition, the roller is held in the cage, and the axial cross-sectional area of the outer diameter side plate of the cage is made larger than the axial cross sectional area of the inner diameter side plate. Even if it is not, the roller can secure a sufficiently high cage strength that can hold the roller even if it is pushed to the outer diameter side by the component force of the thrust load by the outer diameter side plate of the cage.

  In the above case, the roller is pushed in the outer diameter side direction by subjecting the rolling surface of the roller to full crowning and setting the taper angle of the rolling surface smaller than the taper angle of the raceway surface of the raceway. It is possible to reduce the rotational torque by reducing the component force of the thrust load and reducing the contact frictional force between the outer diameter side end surface of the roller and the inner surface of the outer diameter side end portion of the cage.

  The full crowning is preferably set so that the position where the crowning depth is 0.5 μm from the outermost diameter position of the roller is within 10% of the entire roller length.

  As described above, in the thrust roller bearing according to the present invention, an increase in rotational torque caused by differential slip of the roller can be suppressed at a low production cost. Can respond.

  According to the present invention, the rotational torque caused by differential slip can be reduced by a structure that can be manufactured at low cost.

  Hereinafter, a thrust roller bearing according to Embodiment 1 of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view showing the thrust roller bearing, and FIG. 2 is a plan view showing the cage of FIG. FIG. 3 is an enlarged cross-sectional view showing a main part of FIG. First, referring to FIG. 1 to FIG. 3, the pair of bearing rings 12, 14 of the thrust roller bearing 10 has an annular shape extending inward and outward in the radial direction with the bearing central axis S as the center, and is mutually in the direction of the bearing central axis S. Opposite. The raceway surfaces 12a and 14a of both raceways 12 and 14 are provided with raceway surfaces 12a and 14a that are tapered in the radial direction. Both the raceway surfaces 12a and 14a have a frustoconical shape in the radial cross section between them. The cone apex is indicated by C. The cone apex C coincides with the bearing center axis S. The outer diameter side end portions 12b, 14b connected to the raceway surfaces 12a, 14a of the raceways 12, 14 have a flat structure in the radial direction without wrinkles. The outer diameter side ends 12b and 14b are not flat in the radial direction but can be tapered.

  A plurality of rollers 16 are arranged between both raceway surfaces 12a and 14a. In the roller 16, the rolling surface 16a is a tapered rolling surface with respect to the radial direction. The rolling surface 16a has a frustoconical radial cross-sectional shape. The taper angles of the raceway surfaces 12a and 14a and the rolling surface 16a are substantially the same.

  The cage 18 has an annular shape extending inward and outward in the radial direction centered on the bearing center axis S, and includes a plurality of pocket holes 18a at equal intervals in the circumferential direction, and the rollers 16 are rotatably held in the pocket holes 18a. is doing. The cage 18 includes annular inner and outer side plates 18b and 18c, and a plurality of cage columns 18d that connect opposite sides of the side plates 18b and 18c at equal intervals in the circumferential direction. A pocket hole 18a is provided between the cage posts 18c. The pocket hole 18a has a truncated cone shape similar in shape to the roller rolling surface 17a.

  In the cage 18 described above, the axial sectional area of the outer diameter side plate 18c is larger than the axial sectional area of the inner diameter side plate 18b. The cage 18 is formed of a material containing carbon fibers and has improved strength.

  As described above, since the outer diameter side ends 12b and 14b of the race rings 12 and 14 are free of wrinkles, the race rings 12 and 14 can be manufactured at low cost. Further, since the axial sectional area of the outer diameter side plate 18b of the cage 18 is made larger than that of the inner diameter side plate 18c, the strength of the cage 18 can be ensured.

  The form of increasing the cross-sectional area of the outer diameter side plate 18b can be determined by variously setting the ratio between the length in the radial direction and the length in the bearing central axis C direction.

  In addition, as shown in FIG. 4, the inner diameter side surface 18b1 of the outer diameter side plate 18b of the cage 18 is formed in a radially inwardly curved shape and is in contact with the outer diameter side end surface 16b of the roller 16. The contact friction between the cages 18 and 16 can be reduced, and the rotational torque can be reduced. The outer diameter side end face 16b of the roller 16 is formed in a radially outwardly curved shape, so that the contact friction between the cage 18 and 16 can be reduced, and the rotational torque can be reduced.

  As shown in FIG. 5, as the second embodiment of the present invention, the raceway surface 12a of one raceway ring 12 out of the raceway ring 12 and the raceway ring 14 is a flat surface that is substantially orthogonal to the rotation center axis S. The raceway surface 14a of the other raceway ring 14 is set so that the relative inclination angle formed with the raceway surface 12a is substantially the same as the taper angle of the roller 16 which is a tapered roller. Yes. In such a configuration, the cage 18 is also set so that the cross-sectional area of the outer-diameter side plate 18d is larger than the cross-sectional area of the inner-diameter side plate 18c. The effect by this structure is the same as that of Embodiment 1.

  A thrust roller bearing according to Embodiment 3 of the present invention will be described with reference to FIGS. FIG. 6 is a cross-sectional view showing the main part of the thrust roller bearing 10, and FIG. 7 is a diagram for explaining the component force of the thrust load. In the second embodiment, the taper angle of the rolling surface 16a of the roller 16 is made smaller than the taper angle of the raceway surfaces 12a, 14a of the race rings 12, 14, and full rolling is applied to the rolling surface 16a of the roller 16. It is characterized by that. Here, the taper angle of the roller 16 is θ1, the taper angle of the raceway surfaces 12a and 14a is θ2, and θ1 <θ2. The taper angle θ1 is an angle formed by the extended line L1 connecting the ends A and B of the full crowning excluding the chamfers at both ends of the roller 16 and the radial line L2, and the taper angle θ2 is the track surface 12a. This is the angle formed by the extended line of the raceway surface 12a and the radial line L3. P and Q are contact portions with the raceway surfaces 12a and 14a, that is, the rolling surface 16a due to the full crowning on the rolling surface 16a of the roller 16.

  When a thrust load W in the direction of the bearing center axis S is applied to the roller rolling surface 16a, the contact force P1 between the roller rolling surface 16a and the raceway surfaces 12a and 14a has a normal component W1. The component force W2 in the direction to push 16 is applied. In this case, by setting the taper angles θ1 and θ2 to the relationship θ1 <θ2, the component force W2 in the direction of pushing the roller 16 toward the outer diameter side is reduced, and the outer diameter side end face 16b of the roller 16 and the cage 18 are reduced. As a result, the contact friction with the outer diameter side inner surface 18a1 of the pocket hole 18a is reduced. The reason why the roller rolling surface 16a is fully crowned is to enable the relationship of the taper angle θ1 <θ2 to be set.

  In the third embodiment, as in the first embodiment, since the outer diameter side ends 12b and 14b of the race rings 12 and 14 are free of wrinkles, the race rings 12 and 14 can be manufactured at low cost. Moreover, since the cross-sectional area of the outer diameter side plate 18b of the cage 18 is made larger than that of the inner diameter side plate 18c, the strength of the cage 18 can be ensured. In addition, in the second embodiment, since the taper angle θ1 of the roller 16 is set to be equal to or smaller than the taper angle θ2 of the raceway surfaces 12a and 14a, the roller 16 is deformed by the roller pushed to the outer diameter side by the thrust load component W2. The fear can be reduced, and the roller 16 can be held freely rolling.

2 is a cross-sectional view of a thrust roller bearing according to Embodiment 1. FIG. It is a top view of the holder | retainer of FIG. It is sectional drawing which expands and shows the principal part of the thrust roller bearing of FIG. It is a half sectional view which shows the modification of a holder | retainer. 6 is an enlarged cross-sectional view of a main part of a thrust roller bearing according to Embodiment 2. FIG. 6 is an enlarged cross-sectional view of a main part of a thrust roller bearing according to Embodiment 3. FIG. It is a figure where it uses for description of the component force of thrust load in FIG. It is a half sectional view of the conventional thrust roller bearing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Thrust roller bearing 12 Raceway 12a Raceway 14 Raceway 14a Raceway 16 Roller 16a Rolling surface 18 Cage 18a Pocket hole 18b Outer diameter side plate 18c Inner diameter side plate

Claims (2)

  In a thrust roller bearing in which a plurality of rollers are arranged between the raceway surfaces of both raceways and these rollers are held in a cage so as to be able to roll freely, the circumferential speed difference between the inner diameter side and the outer diameter side of the roller rolling surface is determined. Tapered to eliminate, correspondingly at least one of the raceway surfaces is tapered, and the outer diameter side end of the race is free of wrinkles, and in addition, the axial direction of the outer diameter side plate of the cage A thrust roller bearing characterized in that the cross-sectional area is larger than the axial cross-sectional area of the inner diameter side plate. The thrust roller bearing according to claim 1, wherein the rolling surface of the roller is subjected to full crowning, and the taper angle of the rolling surface is set smaller than the taper angle of the raceway surface of the raceway. .

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