JP2005351356A - Double row thrust needle roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double row thrust needle roller bearing capable of exhibiting enhanced performance in low noise and low vibration. <P>SOLUTION: In this double row thrust needle roller bearing, a plurality of rollers are arranged along the radial direction of the bearing. The mutual difference between a diameter of the outer side roller 3 positioned on the outer side of the radial direction and a diameter of the inner side roller 2 positioned on an inner side of the radial direction is equal to or less than 2 μm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a double-row thrust needle roller bearing, and more particularly to a double-row thrust needle roller bearing used in a compressor for an air conditioner, an automatic transmission, an electric brake, or the like of an automobile.

  Generally, thrust needle roller bearings are known as being composed of a bearing ring, a plurality of needle rollers, and a cage, and can realize high load capacity and high rigidity with a simple structure. Further, since the thrust needle roller bearing has advantages such as a small axial height (thickness), it is widely used for applications that require space saving, such as compressors.

  In the thrust needle roller bearing, differential slip occurs between the roller and the raceway because of its basic structure. More specifically, in the case of a thrust needle roller bearing, a cylindrical needle roller is arranged as a rolling element on a raceway having a flat raceway surface, and the roller and the raceway surface are in line contact. It has become. The center of rotation of the bearing coincides with the center of revolution of the roller. Although the roller has a predetermined length in the radial direction of the bearing, the peripheral speed on the rolling surface of the roller is the same speed. On the other hand, the circumferential speed of the raceway surface of the race which is in rolling contact with the roller increases from the center of rotation of the bearing toward the outer diameter direction. Therefore, the peripheral speed difference between the roller and the raceway surface of the raceway is maximized at both ends of the roller.

  Theoretically, pure rolling motion is performed only on the pitch circle of the bearing, and the peripheral speed difference between the roller and the raceway surface increases from the point on the pitch circle toward both ends of the roller, and differential slip increases. . This differential slip increases in proportion to the length of the roller.

  The differential sliding in thrust needle roller bearings is large compared to other types of bearings. Therefore, due to differential slip, edge stress is likely to occur between the roller edge and the bearing ring, and surface-origin separation is likely to occur at the edge of the roller rolling part of the bearing ring. .

  As a measure for alleviating the effect of differential slip between the roller and the raceway surface of the raceway, it is conceivable to shorten the length of the roller. However, if the length of the roller is simply shortened, the contact area of the roller becomes small, so that the contact surface pressure of the roller increases and there is a possibility that problems such as early peeling occur on the outer surface of the roller.

  As a means for improving the above problem, a double-row thrust needle roller bearing has been proposed. In the case of this bearing, by arranging a plurality of rollers in the radial direction of the bearing while shortening the length of the rollers, the contact surface pressure acting on the rollers can be kept low while alleviating the effect of differential sliding. it can.

  Double row thrust needle roller bearings are disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-97562 (Patent Document 1), Japanese Patent Application Laid-Open No. 2003-156050 (Patent Document 2), and Japanese Patent Application Laid-Open No. 2004-36849 (Patent Document 3). It is disclosed.

  In the double-row thrust needle roller bearing disclosed in Japanese Patent Laid-Open No. 2003-97562 (Patent Document 1), the differential sliding generated on the rolling element surface is reduced, and the load capacity is lowered and the rolling contact surface pressure is increased. In order to suppress this, crowning is formed on the rolling surface of at least one of the plurality of roller rows.

In the double-row thrust needle roller bearing disclosed in Japanese Patent Laid-Open No. 2003-156050 (Patent Document 2), differential sliding is reduced, an increase in rolling contact surface pressure is suppressed, and wear of the raceway ring is reduced. In order to have excellent surface damage resistance, rollers with crowning and carbides with a particle size of 0.6 μm or more to a depth of at least 0.1 mm of the surface layer are 10,000 / mm ² or more and 40000 / mm per single area. ^{And a} bearing ring having less than ^two .

In the double-row thrust needle roller bearing disclosed in Japanese Patent Application Laid-Open No. 2004-36849 (Patent Document 3), in order to reduce drilling wear and reduce the bearing sound, the roller end surface is an F end surface, The roller end face accuracy is 30 μm or less.
JP 2003-97562 A JP 2003-156050 A JP 2004-36849 A

  In recent years, high output and high speed have been promoted for air conditioner compressors, automatic transmissions, electric brakes and the like of automobiles. Along with this, noise and vibration of thrust needle roller bearings used in these parts are increasing. In recent years, when the quietness and comfort of the interior space of automobiles are strongly demanded, further reduction in noise and vibration of thrust needle roller bearings are desired.

  An object of the present invention is to provide a double-row thrust needle roller bearing that exhibits excellent performance in low noise and low vibration characteristics.

  The present invention relates to a double row thrust needle roller bearing in which a plurality of rollers are arranged in the radial direction of the bearing, and the diameter of the outer roller located outside in the radial direction and the diameter of the inner roller located inside in the radial direction. The difference between the two is 2 μm or less. According to such a configuration, the load on the outer roller and the inner roller located on the outer and inner sides in the radial direction of the bearing is equalized, so that the behavior of the outer roller and the inner roller is stabilized, and the vibration of the bearing is reduced. In addition, low noise can be realized.

  In one embodiment, a cage for holding a plurality of rollers includes a plurality of pockets provided at intervals in the circumferential direction, and an outer roller and an inner roller are accommodated in each of the plurality of pockets. By making the difference between the diameters of the inner and outer rollers arranged in one pocket 2 μm or less, the load applied to both rollers can be made uniform.

  In another embodiment, the cage for holding the plurality of rollers is provided at a position radially outside the bearing at a plurality of outer pockets spaced in the circumferential direction and at a position radially inside the bearing. A plurality of inner pockets provided at intervals in the circumferential direction, each of the plurality of outer pockets accommodating an outer roller, and each of the plurality of inner pockets accommodating an inner roller.

  Preferably, the difference between the diameters of the plurality of outer rollers arranged in the circumferential direction is 2 μm or less, and the difference between the diameters of the plurality of inner rollers arranged in the circumferential direction is 2 μm or less.

  Paying attention to the end face shape of the roller, the outer roller has an F end face (plane) or an A end face (round face), and the inner roller has an F end face or an A end face. Therefore, there are four types of combinations of the end face of the outer roller and the end face of the inner roller: F end face and F end face, A end face and A end face, A end face and F end face, and F end face and A end face.

  1 to 3 each show an embodiment of a double-row thrust needle roller bearing according to the present invention. Moreover, FIGS. 4-6 has each shown the arrangement | positioning form of a different roller. In these drawings, the same reference numerals indicate the same or corresponding elements. Further, in these drawings, the bearing race of the bearing is not shown.

  First, the basic structure of a double row thrust needle roller bearing will be described with reference to FIG. The double-row thrust needle roller bearing includes a fixed-side bearing ring (not shown), a rotating-side bearing ring (not shown), and a plurality of rollers 2, which are disposed between the two bearing rings and held by the cage 1. 3. A plurality of rollers 2 and 3 are arranged in the radial direction of the bearing. The roller 2 is disposed inside as viewed in the radial direction, and the roller 3 is disposed outside as viewed in the radial direction. Therefore, in the following description, they are called the inner roller 2 and the outer roller 3.

  There are basically three types of arrangements of the inner roller 2 and the outer roller 3 as shown in FIGS.

  The cage 1 shown in FIG. 4 includes a plurality of pockets 11 provided at intervals in the circumferential direction, and an inner roller 2 and an outer roller 3 are disposed in each pocket 11.

  The cage 1 shown in FIG. 5 has a plurality of outer pockets 12 provided at intervals in the circumferential direction at positions outside the bearing in the radial direction, and a gap in the circumferential direction at positions inside the bearing in the radial direction. A plurality of inner pockets 13, the outer rollers 3 are accommodated in each of the plurality of outer pockets 12, and the inner rollers 2 are accommodated in each of the plurality of inner pockets 13. In the form shown in FIG. 5, the number of inner rollers 2 and the number of outer rollers 3 are the same.

  As in the cage shown in FIG. 5, the cage 1 shown in FIG. 6 has a plurality of outer pockets 12 provided at intervals in the circumferential direction at positions outside the radial direction of the bearing, and the radial direction of the bearing. A plurality of inner pockets 13 that are spaced apart in the circumferential direction at the inner position of each of the plurality of outer pockets. Is housed. In the form shown in FIG. 6, the number of the inner rollers 2 and the number of the outer rollers 3 are different. Specifically, in the illustrated form, the number of outer rollers 3 is greater than that of inner rollers 2.

  4 to 6, two rollers are arranged in the radial direction, but three or more rollers may be arranged in the radial direction.

  In each embodiment shown in FIGS. 1 to 3, the only difference is the form of the cage 1. In the embodiment shown in FIGS. 1 and 3, the cage 1 is composed of a plate-like first member 1 a and a second member 1 b that are joined one above the other. In the case of the cage 1 shown in FIG. 1, the outer peripheral portion of the first member 1a is bent and clamped to the outer peripheral portion of the second member 1b, and the inner peripheral portion of the second member 1b is bent and the first member 1a is bent. It is clamped and clamped to the inner periphery of the.

  In the case of the cage 1 shown in FIG. 3, the outer peripheral portion and the inner peripheral portion of the ring-shaped first member 1a are bent toward the second member 1b side, and the outer peripheral portion and the inner peripheral portion of the second member 1b are bent to the first member. It is bent toward the 1a side. The bent outer peripheral portion and the inner peripheral portion of the first member 1a are fitted into the bent outer peripheral portion and the inner peripheral portion of the second member 1b.

  The cage 1 shown in FIG. 2 is a single part made of, for example, resin.

  The common point in each embodiment is that the mutual difference between the diameter of the outer roller 3 located outside in the radial direction and the diameter of the inner roller 2 located inside in the radial direction is 2 μm or less. is there. If the difference between the diameters of the inner and outer rollers is 2 μm or less, the load applied to the inner and outer rollers becomes uniform, so that the behavior of the rollers is stabilized and the bearing can be reduced in vibration and noise.

  If the difference in diameter is 2 μm or less, either the inner or outer roller may be larger. In the best state, the difference between the inner and outer roller diameters is zero. When three or more rollers are arranged in the radial direction, the difference between the diameters of the entire rollers arranged in the radial direction is set to 2 μm or less.

  Even if the mutual difference in diameter is strictly controlled only for a plurality of rollers arranged in the circumferential direction, if the mutual difference in the diameters of the inner and outer rollers arranged in the radial direction is not strictly managed, contact between the inner and outer rollers may occur. As a result, vibration and sound are deteriorated, which may lead to heat generation of the bearing and further shorten the life of the bearing.

  In addition to setting the difference between the diameters of the plurality of rollers arranged in the radial direction to 2 μm or less, preferably, the difference between the diameters of the plurality of rollers arranged in the circumferential direction is also set to 2 μm or less.

  When attention is paid to the end face shapes of the outer roller 3 and the inner roller 2, the outer roller has an F end face (plane) or an A end face (round face), and the inner roller has an F end face or an A end face. Therefore, there are the following four combinations of the end face of the outer roller and the end face of the inner roller.

  (1) The outer roller 3 is an F end surface, and the inner roller 2 is an F end surface.

  (2) The outer roller 3 is an F end surface, and the inner roller 2 is an A end surface.

  (3) The outer roller 3 is an A end surface, and the inner roller 2 is an F end surface.

  (4) The outer roller 3 is an A end surface, and the inner roller 2 is an A end surface.

  When attention is paid to the lengths of the outer roller 3 and the inner roller 2, they are usually set to the same length. However, depending on the use conditions, the lengths of both may be different. Specifically, the length of the inner roller 2 may be longer than that of the outer roller 3 under use conditions in which the surface pressure increases. Moreover, the length of the outer roller 3 may be longer than that of the inner roller 2 under use conditions in which the roller slip increases. Even when the lengths of the inner and outer rollers are made different, the difference between the diameters of the inner and outer rollers must be 2 μm or less.

  The inventors measured the relationship between the length of the inner and outer rollers and the torque. The results are as follows.

[Test conditions]
Rotational speed: 1000r. p. m.
Load: 7000N
Lubricating oil: Spindle oil [Test results]
When inner and outer roller lengths are the same: 39 N · cm
When outer roller is long: 35 N · cm
When inner rollers are long: 42 N · cm
As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of illustrated embodiment. Various modifications and changes can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  In addition, the thrust needle roller bearing does not necessarily have the fixed-side bearing ring and the rotating-side bearing ring, and may have a structure having a rolling surface directly on the other side of the member to be incorporated.

  The present invention can be advantageously applied particularly to a double-row thrust needle roller bearing used for a compressor for an air conditioner of an automobile, an automatic transmission, an electric brake or the like.

It is sectional drawing which shows one Embodiment of this invention. It is sectional drawing which shows other embodiment of this invention. It is sectional drawing which shows other embodiment of this invention. It is a top view which shows an example of the arrangement | positioning form of a some roller. It is a top view which shows the other example of the arrangement | positioning form of a some roller. It is a top view which shows the further another example of the arrangement | positioning form of a some roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cage, 1a 1st member, 1b 2nd member, 2 inside roller, 3 outside roller, 11 pocket, 12 outside pocket, 13 inside pocket

Claims (5)

In the double row thrust needle roller bearing in which a plurality of rollers are arranged in the radial direction of the bearing,
A double row thrust needle roller bearing, characterized in that the difference between the diameter of the outer roller located outside in the radial direction and the diameter of the inner roller located inside in the radial direction is 2 μm or less. A cage for holding the plurality of rollers;
The retainer includes a plurality of pockets spaced in the circumferential direction,
The double row thrust needle roller bearing according to claim 1, wherein the outer roller and the inner roller are accommodated in each of the plurality of pockets. A cage for holding the plurality of rollers;
The cage includes a plurality of outer pockets spaced circumferentially at positions radially outside the bearing and a plurality spaced circumferentially at positions radially inside the bearing. Including the inside pocket,
The outer rollers are accommodated in each of the plurality of outer pockets,
The double-row thrust needle roller bearing according to claim 1, wherein the inner roller is accommodated in each of the plurality of inner pockets. The difference between the diameters of the plurality of outer rollers arranged in the circumferential direction is 2 μm or less,
The double row thrust needle roller bearing according to any one of claims 1 to 3, wherein a difference in diameter between the plurality of inner rollers arranged in the circumferential direction is 2 µm or less. The double row thrust needle roller bearing according to any one of claims 1 to 4, wherein the outer roller has an F end surface or an A end surface, and the inner roller has an F end surface or an A end surface.

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