JP2008133904A - Thrust bearing made of resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thrust bearing made of resin with more surely reduced frictional resistance and improved manufacturability. <P>SOLUTION: The resin thrust bearing 1 is mounted across a stepped surface of a shaft and a stepped surface of a shaft hole of a housing into which the shaft is inserted, so as to support the shaft. The resin thrust bearing 1 includes sliding surfaces that make sliding contact with the stepped surface of the shaft, concaved parts 12 for defining gaps between the step surface of the shaft and the thrust bearing, and inclined surfaces 13 arranged between the sliding surfaces and the concaved parts 12 so as to define wedge-shaped gaps between the stepped surface of the shaft and the thrust bearing. The inclined surfaces 13 are so inclined that the gaps between the step surface of the shaft and the thrust bearing become narrower toward the sliding surfaces in a direction of rotation of the shaft. A dynamic pressure acting in a direction in which the resin thrust bearing 1 separates from the stepped surface of the shaft is generated due to a flow of the lubricating oil in the wedge-shaped gaps caused by relative rotation of the shaft and the housing. Due to the generation of the dynamic pressure, when the resin thrust bearing 1 in which lubricating oil films are deposited across the stepped surface of the shaft and the sliding surfaces is loaded axially, the angle of inclination of the inclined surfaces 13 becomes appropriate for forming the lubricating oil films. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thrust bearing that supports a shaft by receiving a load in an axial direction, and particularly relates to a resin-made thrust bearing used in a torque converter and a power train of an automatic transmission for an automobile.

  Various sliding plates are used in the automatic transmission for automobiles in order to reduce sliding resistance during movement, and metal needle bearings are the most widely used. However, although a metal needle bearing is excellent as a component for reducing sliding resistance between metal members, there is a limit to saving space in the axial direction. In addition, since the material / manufacturing cost is high, it is difficult to provide at low cost.

  Therefore, what is used as a substitute for a metal needle bearing is a plastic thrust bearing that is low in material cost and excellent in workability. Plastic thrust bearings can be reduced in weight as well as at low cost. However, since the plastic thrust bearing has a higher frictional resistance than the metal needle bearing, when a low frictional resistance is required, a groove shape that generates dynamic pressure by the wedge effect is formed on the sliding surface. It is necessary to reduce the surface pressure of the sliding surface to form an appropriate lubricating oil film on the bearing sliding surface.

  For example, a step shape having an inclined surface as shown in FIGS. 9 and 10 is generally known as a shape that effectively generates dynamic pressure. FIG. 9 is a front view of a resin thrust bearing according to the prior art, and FIG. 10 is a CC cross-sectional view of FIG.

  A resin thrust bearing 100 according to the prior art has a groove 101 that forms a gap with a sliding partner, and an inclination that gradually reduces the gap between the sliding partner in the direction of rotation of the shaft that is the sliding partner. The surface 102 and the sliding surface 103 that is in sliding contact with the sliding partner are sequentially and repeatedly formed in the rotation direction of the shaft that is the sliding partner.

  With such a stepped shape, a wedge-shaped space that becomes narrower in the rotational direction of the shaft is formed between the end face of the resin thrust bearing 100 and the sliding partner. Then, the flow of the lubricating oil in the wedge-shaped space generated by the rotation of the shaft generates a dynamic pressure that acts in a direction in which the resin thrust bearing 100 is separated from the sliding partner.

  Due to the generation of the dynamic pressure, the surface pressure of the sliding surface 103 decreases, and an appropriate lubricating oil film can be formed between the sliding surface 103 and the sliding partner. As a result, the frictional resistance with the sliding partner can be reduced.

Related techniques include those disclosed in the following documents.
Japanese Utility Model Publication No. 3-123118 Japanese Patent Laid-Open No. 10-68413 JP-A-6-300028 Japanese Utility Model Publication No. 2-66718 JP 2001-221232 A WO2002 / 077473 JP 2004-293684 A

  However, when the inclination angle β of the inclined surface 102 is large, dynamic pressure cannot be generated effectively, and a lubricating oil film cannot be formed on the sliding surface 103. Therefore, it is desirable to set the inclination angle of the inclined surface 103 to a certain minute angle. However, such a minute angle setting makes it extremely difficult to manufacture and requires high accuracy. .

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a resin thrust bearing capable of forming a lubrication state more reliably and improving manufacturability. It is to provide.

In order to achieve the above object, the resin thrust bearing in the present invention is:
A step surface between the large diameter portion and the small diameter portion concentrically formed on the shaft, and a step surface between the large diameter portion and the small diameter portion formed concentrically in the shaft hole of the housing into which the shaft is inserted. A plastic thrust bearing mounted between and supporting the shaft,
A sliding surface in sliding contact with the stepped surface of the shaft;
A recess that forms a gap with the stepped surface of the shaft;
Provided between the sliding surface and the recess, and inclined so as to narrow a gap between the stepped surface of the shaft in the rotational direction of the shaft and approach the sliding surface. An inclined surface that forms a wedge-shaped gap between the step surface and
Due to the relative rotation between the shaft and the housing, the flow of lubricating oil generated in the wedge-shaped gap generates a dynamic pressure that acts in a direction in which the resin thrust bearing moves away from the stepped surface of the shaft,
In the resin thrust bearing in which a lubricating oil film is formed between the stepped surface of the shaft and the sliding surface by the generation of the dynamic pressure,
When receiving an axial load, the inclined angle of the inclined surface is an angle suitable for forming the lubricating oil film.

  Thus, when the axial load is received, the inclination angle of the inclined surface becomes an angle suitable for the formation of the lubricating oil film, so that the lubricating state can be more reliably formed during use. In addition, the inclination angle of the inclined surface only needs to be an angle suitable for the formation of the lubricating oil film during use, and therefore, it may not be an angle suitable for the formation of the lubricating oil film during manufacture. Therefore, the manufacturing accuracy required for forming the inclined surface suitable for forming the lubricating oil film at the time of manufacturing is not required, and the manufacturing becomes easy.

The resin thrust bearing is
Providing a protruding part protruding in the axial direction,
The convex part and the concave part have a wavy shape in the circumferential direction in which a plurality of the convex parts and the concave parts are alternately formed in the circumferential direction,
The tip surface of the convex portion pressed against the stepped surface of the shaft by an axial load forms the sliding surface, and
When the waviness is reduced by contraction in the axial direction due to the axial load, the inclination angle of the inclined surface may be an angle suitable for forming the lubricating oil film.

  Thus, when the wavy shape in the circumferential direction contracts in the axial direction due to the axial load, the inclination angle of the inclined surface becomes an angle suitable for the formation of the lubricating oil film. Formation is possible. Further, since the inclined surface may be formed at an inclination angle before being contracted in the axial direction, the manufacturing accuracy required for forming an ideal inclined shape is not required, and the manufacturing is facilitated.

  An angle suitable for forming an appropriate lubricating oil film on the sliding surface may be larger than 0 ° and not larger than 5 °.

  As described above, according to the present invention, the lubrication state can be more reliably formed and the manufacturability is improved.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

(Example)
With reference to FIGS. 1-5, the resin-made thrust bearing which concerns on the Example of this invention is demonstrated. 1A and 1B are views showing the configuration of a resin thrust bearing according to the present embodiment, in which FIG. 1A is a front view seen from the axial direction, FIG. 1B is a perspective view, and FIG. 2A and 2B are cross-sectional views taken along line AA in FIG. 1A. FIG. 2A shows a state where no axial load is applied to the resin thrust bearing according to this embodiment, and FIG. 2B shows a state where the axial load is applied. A cross-sectional view is shown. FIG. 3 is a schematic cross-sectional view showing a mounted state of the resin thrust bearing according to the present embodiment. FIG. 4 is a schematic cross-sectional view showing a specific usage mode of the resin thrust bearing according to the present embodiment. FIG. 5 is a cross-sectional view taken along the line BB in FIG. 3 and shows how dynamic pressure is generated by the rotation of the shaft.

<Configuration and outline of plastic thrust bearing>
First, with reference to FIG. 1, the structure of the resin thrust bearing which concerns on the Example of this invention is demonstrated.

  As shown in FIG. 1, the resin thrust bearing 1 according to the present embodiment is an annular member made of a resin material, and has a shape that undulates in the circumferential direction.

  Specifically, the resin thrust bearing 1 according to the present embodiment has a configuration in which convex portions 11 protruding in the axial direction and concave portions 12 recessed in the opposite direction to the convex portions 11 are alternately formed. . An inclined surface 13 that generates dynamic pressure when the resin thrust bearing 1 is used is formed between the convex portion 11 and the concave portion 12 as described later.

  The resin thrust bearing 1 according to the present embodiment is manufactured by molding, and examples thereof include nylon-based resin, PEEK, and the like. However, any resin material having elasticity can be used as appropriate. it can.

<When installing a plastic thrust bearing>
With reference to FIGS. 2-4, the mode at the time of use of the resin-made thrust bearing which concerns on a present Example is demonstrated.

  As shown in FIG. 3, the resin thrust bearing 1 according to this embodiment includes a stepped portion 22 of a shaft hole 21 provided in the housing 2 and a stepped portion 32 of the shaft 3 inserted into the shaft hole 21. It is mounted between and supports the shaft 3.

  Specifically, a step surface 22a between the large diameter portion 21a and the small diameter portion 21b concentrically formed in the shaft hole 21, and a space between the large diameter portion 31a and the small diameter portion 31b concentric with the shaft 3 are formed. It is sandwiched in the axial direction by the step surface 32a, and receives an axial load from the shaft 3. And the clearance gap between the resin-made thrust bearings 1 and the level | step-difference parts 22 and 32 is filled with lubricating oil in order to reduce frictional resistance.

  Here, with reference to FIG. 4, the specific usage aspect of the resin thrust bearing 1 which concerns on a present Example is demonstrated. FIG. 4 shows an example in which the resin thrust bearing 1 according to this embodiment is applied to an assembly mechanism of a housing 121 and a solenoid valve 130 provided in a torque converter or a power train of an automatic transmission for automobiles.

  Here, the solenoid valve 130 is a valve that is arranged in the hydraulic path and performs conduction control of the hydraulic path. In the solenoid valve 130, when a predetermined current flows through the coil 132 housed in the outer cylinder 131, the needle 133 is displaced in the axial direction by the electromagnetic force generated at that time. Then, using the displacement, the hydraulic oil passage 134 communicating between the hydraulic passages 122 and 123 is turned on or off.

  For example, when high-pressure hydraulic oil is supplied to the hydraulic passage 123 and low-pressure hydraulic oil is supplied to the hydraulic passage 122, when a predetermined current is passed through the coil 132 and the hydraulic oil passage 134 is conducted, the hydraulic passage 123 is connected to the hydraulic passage 123. A hydraulic oil having a flow rate corresponding to the differential pressure and the diameter of the orifice 135 flows toward 122. At this time, the solenoid valve 130 receives a stress corresponding to the flow resistance when the hydraulic oil flows through the orifice 135 in the axial direction thereof.

  On the other hand, when the current flowing through the coil 132 is appropriately switched to block the hydraulic oil passage 134, the hydraulic fluid is blocked from flowing, and the hydraulic pressure generated in the hydraulic passage 123 is directly connected to the solenoid via the ball valve 136 and the needle 133. It is transmitted to the valve 130. Therefore, in this case, the differential pressure between the hydraulic passages 123 and 122 acts on the solenoid valve 130 in the axial direction.

  That is, in the solenoid valve 130 of the present embodiment, the hydraulic pressure applied in the axial direction greatly varies every time the hydraulic oil passage 134 is turned on or off. For this reason, the assembly mechanism of the solenoid valve 130 and the housing 121 is required to be easy to assemble and to have a configuration capable of ensuring sufficient stability against such axial stress fluctuations. .

  Here, O-rings 137 and 138 are disposed between the housing 121 and the solenoid valve 130 in order to ensure sealing performance against hydraulic oil, and a C-ring 139 is used as a mechanism for preventing the solenoid valve 130 from coming off. Yes.

  In this case, as shown in FIG. 4, the C ring 139 is sandwiched between a groove 121 a provided in the housing 121 and a flange 131 a provided in the outer cylinder 131 of the solenoid valve 130, and acts on the solenoid valve 130. It is possible to stably receive the stress in the axial direction. At this time, the resin thrust bearing 1 of this embodiment mounted between the step portion 22 ′ of the housing 121 and the step portion 32 ′ of the outer cylinder 131 urges the solenoid valve 130 upward in FIG. Thus, the C ring 139 acts to secure the clamping force.

  In this case, the operating temperature is assumed to be -40 ° C to 140 ° C (maximum instantaneous temperature 160 ° C), the amount of lubricating oil supplied is 300 cc or more per minute, and the maximum bearing load is 3000 N or less. The

  Next, with reference to FIG. 2, a state when the resin thrust bearing 1 according to the present embodiment is deformed by the axial load L will be described.

In a state where the axial load (axial load) L is not acting (that is, when the plastic thrust bearing 1 is manufactured), the swell height (axial height) of the resin thrust bearing 1 is H1. It has become.

  When the axial load L is received from the shaft 3, the resin thrust bearing 1 is elastically compressed in the axial direction, and the undulation height is reduced from H1 to H2. At this time, the inclination angle α2 of the inclined surface 13 is such that a dynamic pressure is generated between the stepped surface 32a of the shaft 3 and the resin thrust bearing 1 during use, and a lubricating oil film is formed on the sliding surface with the stepped surface 32a. An angle suitable for the above (greater than 0 ° and not more than 5 °).

  Therefore, since the inclination angle α1 of the inclined surface 13 in a state where the axial load L is not acting is naturally larger than the inclination angle α2 when the axial load L is applied, high production accuracy is required in the production stage. The inclined surface 13 may be formed at an inclination angle α1 that is larger than the minute inclination angle α2.

  When the resin thrust bearing 1 according to the present embodiment is manufactured, dimension settings such as the angle of the inclined surface in a state where no axial load is applied (the axial thickness t of the resin thrust bearing 1, the swell height) (H1 etc.) is appropriately set depending on the specifications and usage environment of the resin thrust bearing, the type of material selected, and the like. That is, what is necessary is just to set so that the inclination angle of the inclined surface 13 finally becomes the minute angle α2 when the axial load is applied and compressed in the axial direction.

  Next, with reference to FIG. 5, the state of dynamic pressure generation by the inclined surface 13 of the resin thrust bearing 1 according to the present embodiment will be described.

  As shown in FIG. 5, the resin thrust bearing 1 is compressed in the axial direction by an axial load, whereby the tip portion of the convex portion 11 is pressed against the stepped surface 32a of the shaft 3 to form the sliding surface 11a. The inclined surface 13 of the resin thrust bearing 1 forms a wedge-shaped gap with the step surface 32 a of the shaft 3. The inclination angle of the inclined surface 13 at this time is an angle (greater than 0 ° and not more than 5 °) suitable for forming a lubricating oil film between the step surface 32a and the sliding surface 11a.

  The wedge-shaped gap is formed by the inclined surface 13 of the resin thrust bearing 1, the inner peripheral surface of the large-diameter portion 21a of the housing 2, the outer peripheral surface of the small-diameter portion 31b of the shaft 3, and the step surface 32a of the shaft 3. Thus, the width of the axial direction becomes narrower toward the rotation direction (R direction) of the shaft 3.

  When the shaft 3 rotates in the R direction with respect to the housing 2, a part of the lubricating oil filled between the resin thrust bearing 1 and the step portions 22 and 32 is dragged by the rotation of the shaft 3 in the R direction. A flow F heading toward is generated.

  Since the wedge-shaped gap between the inclined surface 13 and the step surface 32a becomes narrower toward the rotation direction (R direction) of the shaft 3, the lubricating oil flows toward a narrower space. Then, in the vicinity of the tip of the wedge-shaped gap (near the boundary with the sliding surface 11 a), the pressure is locally increased by the flowing lubricating oil, and as a result, the resin thrust bearing 1 is moved from the step surface 32 a of the shaft 3. A dynamic pressure P acting in the direction of separating is generated (wedge effect).

  Due to this dynamic pressure P, the surface pressure between the step surface 32a and the sliding surface 11a decreases, and the lubricating oil easily enters between the step surface 32a and the sliding surface 11a. As a result, an oil film made of lubricating oil is formed between the step surface 32a and the sliding surface 11a, and the sliding resistance between the step surface 32a and the sliding surface 11a is reduced.

<Reason why the inclination angle is greater than 0 ° and less than 5 °>
Here, it will be described based on the analysis results shown in FIGS. 6 to 8 that an appropriate oil film can be formed when the inclination angle of the inclined surface is greater than 0 ° and not more than 5 °.

  FIG. 6 is a schematic diagram showing a schematic configuration of an inclined shape used in this analysis. FIG. 7 is a chart showing the relationship between the height (hi-ho) of the inclined surface and the inclination (m) of the inclined surface when the circumferential length of the inclined surface is 5 mm. It is a graph which shows the relationship between the length (B1) of the circumferential direction of an inclined surface, and the thickness of a lubricating oil film.

  From the results shown in FIG. 8, when m is up to 10, a certain amount of oil film thickness can be secured, but when m is 100, the oil film thickness is drastically decreased. I understand. Therefore, it can be seen that the inclination angle must be set to be larger than 0 ° and not larger than 5 ° in order to make the sliding surface in an appropriate lubricating state.

<Excellent point of resin thrust bearing according to this embodiment>
According to the resin thrust bearing 1 according to the present embodiment, the inclination angle of the inclined surface 13 is small enough to form a lubricating oil film on the sliding surface 11a when compressed in the axial direction (0 °). Therefore, in the manufacturing stage of the resin thrust bearing 1, it is necessary to form the inclination angle of the inclined surface 13 at a minute inclination angle that requires high manufacturing accuracy. , And the productivity is improved.

  That is, since the inclination angle α1 of the inclined surface 13 at the time of manufacture (when the axial load is not applied) can be set larger than the inclination angle α2 at the time of use (when the axial load is applied), the manufacture is facilitated.

  In the case of a resin thrust bearing manufactured by molding, 5 is greater than 0 °, which is a fine tilt angle suitable for forming a lubricant film on the inclined surface 13 on the sliding surface 11a by molding in advance. Although it is very difficult to mold at an angle of less than or equal to °, according to the resin thrust bearing 1 according to the present embodiment, the resin-made thrust bearing 1 is provided with the inclined surface 13 having such a small inclination angle (when an axial load is applied) The thrust bearing 1 can be easily manufactured by molding.

  Further, when the resin thrust bearing 1 is compressed in the axial direction in use, the inclination angle of the inclined surface 13 becomes an inclination angle suitable for forming a lubricating oil film on the sliding surface 11a. The lubricating oil film can be reliably formed by 11a, and the frictional resistance can be more reliably reduced.

The block diagram of the resin-made thrust bearing which concerns on a present Example. The figure which shows the mode at the time of the effect | action of the axial load of the resin-made thrust bearing which concerns on a present Example. Sectional drawing which shows the mounting state of the resin thrust bearing which concerns on a present Example. The typical sectional view showing the concrete usage mode of the resin thrust bearing concerning this example. The figure which shows the mode of generation | occurrence | production of dynamic pressure. The schematic diagram of the inclination shape used for the analysis. The chart which shows the relationship between the height of an inclined surface, and inclination. The chart which shows the relationship between an inclination angle and the thickness of a lubricating oil film. The front view of the resin-made thrust bearing which concerns on a prior art. Sectional drawing of the resin thrust bearing which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plastic thrust bearing 11 Convex part 11a Sliding surface 12 Concave part 13 Inclined surface 2 Housing 21 Shaft hole 22 Step part 22a Step surface 3 Shaft 32 Step part 32a Step surface

Claims (3)

A step surface between the large diameter portion and the small diameter portion concentrically formed on the shaft, and a step surface between the large diameter portion and the small diameter portion formed concentrically in the shaft hole of the housing into which the shaft is inserted. A plastic thrust bearing mounted between and supporting the shaft,
A sliding surface in sliding contact with the stepped surface of the shaft;
A recess that forms a gap with the stepped surface of the shaft;
Provided between the sliding surface and the recess, and inclined so as to narrow a gap between the stepped surface of the shaft in the rotational direction of the shaft and approach the sliding surface. An inclined surface that forms a wedge-shaped gap between the step surface and
Due to the relative rotation between the shaft and the housing, the flow of lubricating oil generated in the wedge-shaped gap generates a dynamic pressure that acts in a direction in which the resin thrust bearing moves away from the stepped surface of the shaft,
In the resin thrust bearing in which a lubricating oil film is formed between the stepped surface of the shaft and the sliding surface by the generation of the dynamic pressure,
A resin thrust bearing characterized in that, when an axial load is applied, the inclined angle of the inclined surface is an angle suitable for forming the lubricating oil film. The resin thrust bearing is
Providing a protruding part protruding in the axial direction,
The convex part and the concave part have a wavy shape in the circumferential direction in which a plurality of the convex parts and the concave parts are alternately formed in the circumferential direction,
The tip surface of the convex portion pressed against the stepped surface of the shaft by an axial load forms the sliding surface, and
2. The resin thrust bearing according to claim 1, wherein an inclination angle of the inclined surface becomes an angle suitable for formation of the lubricating oil film when the undulation is reduced due to contraction in an axial direction due to an axial load. .   3. The resin thrust bearing according to claim 1, wherein an angle suitable for forming an appropriate lubricating oil film on the sliding surface is greater than 0 ° and 5 ° or less. 4.

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