KR20220135316A - A Thrust Roller Bearing - Google Patents

Abstract

The present invention relates to a thrust roller bearing (1) which comprises: a plurality of rollers (2) arranged in a circumferential direction; and a cage (3) having a plurality of pockets formed in the circumferential direction to store the rollers (2). Chamfering units (2a) are formed on both sides in a longitudinal direction of the roller in at least one of the rollers (2), and a Teflon coating layer (2b) is formed in the chamfering unit (2a).

Description

Thrust Roller Bearing {A Thrust Roller Bearing }

The present invention relates to thrust roller bearings (including thrust needle-shaped roller bearings), and more specifically, to automobile transmissions (manual and automatic), transfers, or compressors of automobile air conditioners. , relates to a thrust bearing used to support the thrust load applied to this rotating part.

Thrust roller bearings include a plurality of rollers arranged radially at equal times in a circumferential direction; It consists of raceways located on both sides of the axial direction, that is, a first raceway and a second raceway. Each of these first and second raceways is made into a ring shape by a metal plate having sufficient hardness. Among them, the first raceway has a ring-shaped first raceway raceway surface, and the second raceway has a ring-shaped second raceway raceway surface.

Thrust roller bearings are bearings with various advantages such as high load capacity and high rigidity with a simple structure. Moreover, there is a case where the above-mentioned raceway is not used and only a cage and a roller structure are used. In this case, the shaft or housing, which becomes the relative raceway of the raceway of the roller, has functions equivalent to the bearing raceway, such as roughness and hardness, and the shaft or housing is used as the raceway, so that the raceway is unnecessary. and compactness is possible. In particular, thrust needle roller bearings using needle-shaped rollers (needle rollers) as rollers can reduce the cross-sectional height of the bearing, and are particularly suitable for compact mechanical design.

In a general type of bearing (for example, a ball bearing, etc.), differential slip occurs between a rolling element and a raceway. It depends on the circumferential speed difference in the interior. That is, in the case of point contact of a ball bearing or the like, since the contact area is small, it can be said that the circumferential speed difference between them in the contact surface is small and the differential slip is small.

In addition, the thrust roller bearing has a structure in which a cylindrical roller as a rolling element is disposed on a raceway having a flat raceway surface, the roller and the raceway are in linear contact, and the rotational center of the bearing is the revolution of the roller. It has a basic structure that coincides with the center. In this case, the circumferential speed on the rolling surface of the roller is the same speed, but on the other hand, as the raceway that is in rolling contact with the roller moves from the center of rotation of the bearing toward the outer diameter (in proportion to the radius of rotation of the raceway), speed is increased Therefore, the circumferential speed difference between the roller and the raceway becomes maximum at both ends of the roller. Theoretically, pure rolling motion is performed only on the circular pitch of the bearing, and from the point on the circular pitch of the roller toward both ends of the roller, the circumferential speed difference between the roller and the raceway increases, and the differential slip increases. This differential slip is proportional to the length of the rollers.

As described above, the differential slippage within the bearing in the thrust roller bearing is large compared to that of other types of bearings. For this reason, differential sliding between the roller and the raceway is a factor, and in the edge portion of the roller, edge stress between the raceway and the raceway is likely to occur, and the surface of the edge portion of the front periphery of the raceway is It becomes easy to generate|occur|produce the peeling of a starting point type.

As a solution to the above problem, countermeasures such as forming a chamfer on the roller have been implemented for a problem in which a stress (edge rod) is generated at the end of the roller (Japanese Patent Application Laid-Open No. 9-14131). Thrust roller bearings are required to reduce the size of the bearing in response to demands such as energy saving, space saving, and weight reduction (reducing friction loss). Therefore, the bearing usage conditions are more severe in terms of load capacity. As described above, in thrust roller bearings, the differential slip between the roller and the raceway is the cause, and the oil film formation state on the contact surface is deteriorated. and the surface origin-type peeling tends to occur at the edge portion of the front periphery of the raceway. In order to suppress differential slippage, it is considered to simply shorten the roller length, but since the contact area of the rollers becomes small, the contact surface pressure increases. For this reason, the contact surface pressure at the contact surface increases, the oil film formation state deteriorates, and abnormalities, such as peeling generate|occur|produces on the outer diameter side of a roller, generate|occur|produce. Therefore, it is proposed to increase the lubricity between the rolling element and the raceway by coating a solid lubricant such as molybdenum disulfide on the raceway surface of the rolling element and the raceway surface of the raceway by using the mechanical energy obtained from ball mill barrel processing, shot peening, etc. .

Japanese Patent Laid-Open No. Hei 6-159373

The present invention has been proposed to solve the above problems, and an object of the present invention is to provide a thrust roller bearing with excellent lubricity between a chamfered portion of a roller and a raceway and a long bearing life.

For the above purpose, the present invention provides a thrust roller bearing having a plurality of rollers arranged in a circumferential direction and a cage having a plurality of pockets formed along the circumferential direction to accommodate the rollers, wherein at least one of the rollers is provided. Provided is a thrust roller bearing in which one roller has chamfered portions formed on both sides in the longitudinal direction of the roller, and a Teflon coating layer is formed on the chamfered portions.

In the above, the radially outer end of the Teflon coating layer coincides with the radially outer end of the roller, and the end of the Teflon coating layer in the longitudinal direction of the roller coincides with the end of the roller.

In the above, the stacked thickness of the techron coating layer is characterized in that less than 0.1㎛.

In the above, it is characterized in that a Teflon coating layer is formed inside the pocket of the cage.

According to the present invention, the lubricity between the chamfered portion of the roller and the raceway is excellent, so that the bearing life is prolonged. In addition, by forming the Teflon coating layer on the chamfered portions formed on both sides in the longitudinal direction of the roller, the lubricity of the chamfered portion and the raceway is increased, the edge stress is reduced, and the Teflon coating layer is prevented from falling off due to roller sliding due to excessive coating.

1A is a longitudinal cross-sectional view showing a thrust roller bearing of the present invention,
Fig. 1B is a plan view of the upper half of the roller and cage in Fig. 1A,
2 is a view showing a roller in a thrust roller bearing according to an embodiment of the present invention;
Fig. 3 is an enlarged longitudinal sectional view of a roller and a cage surface in still another thrust roller bearing according to the embodiment of the present invention.

All technical and scientific terms used in the description of the present invention, unless otherwise defined, have the meanings commonly understood by one of ordinary skill in the art to which this disclosure belongs. All terms used in the present disclosure are selected for the purpose of more clearly describing the present disclosure and not to limit the scope of the present disclosure.

As used in the description of the present invention, expressions such as "comprising", "including", "having", etc., contain the possibility of including other embodiments, unless otherwise stated in the phrase or sentence in which the expression is included. It should be understood in open-ended terms.

Expressions in the singular used in the description of the present invention may include the meaning of the plural unless otherwise indicated, and the same applies to expressions in the singular in the claims.

Expressions such as “first” and “second” used in the description of the present invention are used to distinguish a plurality of components from each other, and do not limit the order or importance of the components.

In the description of the present invention, when a component is referred to as being “connected” or “coupled” to another component, the component can be directly connected to or coupled to another component, or a new other component. It should be understood that the components may be connected or coupled via the medium.

Hereinafter, a preferred embodiment of a thrust roller bearing according to the present invention will be described in detail with reference to the drawings.

As shown in Figs. 1A and 1B, the thrust roller bearing 1 includes a plurality of rollers 2 arranged in an equal number radially in the circumferential direction, and the plurality of rollers 2 are formed in a ring shape. A cage (3) for freely supporting the roller (2), and a first raceway (4) and a second raceway (4) provided on both sides of the cage (3) in the axial direction and contacting the roller (2) 5) consists of These 1st raceway 4 and 2nd raceway 5 are made into a ring shape by the metal plate which has sufficient hardness.

The first raceway 4 is provided with a ring-shaped first raceway raceway surface 6 , and the second raceway 5 is provided with a ring-shaped second raceway raceway surface 7 .

The roller 2 is made of metal, and chamfered portions 2a are formed on the inner and outer sides of the radius, which are both sides in the longitudinal direction, and a Teflon coating layer 2b is formed on the chamfered portions 2a.

A Teflon coating layer (2b) is provided on the chamfered portion (2a) to increase lubricity, thereby increasing the circumferential speed difference between the roller (2) and the raceway (4, 5), and the differential slippage is increased on both sides of the roller (2) in the longitudinal direction The edge stress that is likely to occur between the raceways 4 and 5 is reduced, and Delamination is reduced and bearing life is improved.

The outer diameter surface of the Teflon coating layer (2b) is continuous to the outer diameter surface of the roller (2). That is, the radially outer end of the Teflon coating layer (2b) coincides with the radially outer end of the roller (2). The radially outer end of the Teflon coating layer (2b) coincides with the radially outer end of the roller (2) so that the outer diameter of the roller (2) is continuously formed with the techron coating layer (2b), and the roller (2) No step is formed between the outer diameter surface of the Teflon coating layer (2b).

The end of the Teflon coating layer 2b in the longitudinal direction of the roller 2 coincides with the end of the roller 2 . The end of the Teflon coating layer (2b) in the longitudinal direction of the roller (2) coincides with the end of the roller (2), so that in the longitudinal direction of the roller (2), the techron coating (2b) is separated from the roller (2). does not protrude

The maximum thickness of the techron coating layer (2b) is preferably formed to be 0.1 micrometers or less. The maximum thickness of the techron coating layer (2b) is formed to be 0.1 micrometers or less, thereby preventing the Teflon coating layer from falling off due to roller sliding due to the formation of an excessively thick coating layer.

The cage 3 is spaced apart along the circumferential direction in an annular shape to form a plurality of pockets in which the roller 2 is accommodated. Each of the rollers 2 is accommodated in a pocket of the cage 3 so that the circumferential spacing of the rollers 2 is maintained. The cage 3 has an annular shape having the same diameter, and is spaced apart in the axial direction, with a pair of ring portions arranged concentrically with each other, and a state placed between the pair of ring portions at equal intervals in the circumferential direction. It may be formed by a plurality of pillar portions provided as a, and a portion surrounding the four circumferences by a pair of ring portions and a pillar portion adjacent to each other in the circumferential direction.

As shown in FIG. 3 , a Teflon coating layer 3a is formed inside the pocket of the cage 3 . As the Teflon coating layer 3a is formed inside the pocket of the cage 3, the roller 2 accommodated in the pocket rolls in contact with the Teflon coating layer 3a. Even if sufficient lubricating oil is not supplied between the cage 3 and the roller 2, the roller 2 rolls in contact with the Teflon coating layer 3a. Lifespan is improved.

2: rolling element 3: cage
4: 2nd track wheel 5: 1st track wheel
6, 7: Orbital surface

Claims (4)

A thrust roller bearing (1) having a plurality of rollers (2) arranged along a circumferential direction and a cage (3) having a plurality of pockets formed along the circumferential direction to accommodate the roller (2), the roller At least one roller in (2) has chamfered portions (2a) formed on both sides in the longitudinal direction of the roller, and a Teflon coating layer (2b) is formed on the chamfered portion (2a). According to claim 1, wherein the radially outer end of the Teflon coating layer (2b) coincides with the radially outer end of the roller (2) and the end of the Teflon coating layer (2b) in the longitudinal direction of the roller (2) ), which coincides with the end of the thrust roller bearing. The thrust roller bearing according to claim 2, wherein the stacked thickness of the techron coating layer (2b) is 0.1 μm or less. The thrust roller bearing according to claim 1, wherein a Teflon coating layer (3a) is formed inside the pocket of the cage (3).

Images