JP2006322529A - Thrust bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thrust bearing whose wear is avoided by preventing the entry of muddy water from a gap between race portions or between cases into the bearing. <P>SOLUTION: A rolling element storage space 25 in which polymer lubricant 35 is filled serves as a cage. The polymer lubricant 35 is filled in part of an inside gap portion 20 in the form of exposing a surface 35a to the inside gap portion 20. The polymer lubricant 35 is also filled in part of an outside gap portion 21 in the form of exposing a surface 35b to the outside gap portion 21. The polymer lubricant 35 filled in the inside gap portion 20 and the outside gap portion 21 serves as a seal portion to prevent the passage of muddy water or dust from a space outside the bearing to the rolling element storage space 25. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thrust bearing used in a strut suspension device for a vehicle.

  2. Description of the Related Art In a strut suspension of a vehicle, a thrust bearing is provided to hold wheels on both sides while following the swinging motion of a strut piston rod between a strut and a vehicle body during steering (for example, Patent Literature 1, 2).

  In a thrust bearing used for a strut suspension, a plurality of balls are interposed between two pairs of annular races, and a gap is formed between end portions of both races. There is a problem that muddy water or the like enters the rolling elements from the gap between the cases, and in order to solve this problem, the elastic sealing material directly bonded to one race is sealed by bringing it into contact with the other race. There is what I did.

  FIG. 6 shows a thrust bearing 101 provided with an elastic seal material. The thrust bearing 101 includes a first race 103, a second race 104, a plurality of balls 102 disposed between the first race 103 and the second race 104, a first race 103, An elastic sealing material 105 that seals a gap between the second race 104 and the second race 104 is provided. The elastic sealing material 105 includes an inner seal portion 106 that seals the inner gap and an outer seal portion 107 that seals the outer gap, and prevents liquid infiltrates such as muddy water from entering the ball 102 from both gaps. It is out.

JP 2001-140903 A JP 2002-227861 A

  However, the one using the elastic sealing material 105 has a problem in durability because the elastic sealing material 105 is worn with sliding. In addition, there is a problem that the region where the elastic sealing material 105 is bonded is also restricted by the structure of the race.

  A plurality of balls are interposed between the two ring-shaped race rings, and a gap between cases is formed between the upper case supporting the first race ring and the lower case supporting the second race ring. Similarly, the thrust ball bearing used has a problem that liquid infiltrates such as muddy water enter from the gaps between the cases.

  An object of the present invention is to provide a thrust bearing that prevents muddy water and the like from entering the inside of the bearing from the gap between the race portion and the race portion, or the gap between the case and the case, and does not cause wear.

Means for Solving the Problems and Effects of the Invention

The thrust bearing of the present invention for solving the above problems is
A thrust bearing supported by a coil spring seat and an upper portion of a strut piston rod, wherein one of the race rings is fixed to the strut piston rod;
A first rolling element housing space forming section that has a first raceway surface forming section that supports a plurality of rolling elements from an axial direction, and that forms a rolling element housing space that houses the rolling element;
A second rolling element housing space that has a second raceway surface forming section that supports the rolling elements in the axial direction opposite to the first raceway surface forming section, and forms a rolling element housing space together with the first rolling element housing space forming section. A forming part,
The first rolling element housing space forming portion and the second rolling element housing space forming portion are arranged to face each other in the form of forming an external gap communicating with the rolling element housing space outside the rolling element housing space,
The rolling element housing space is filled with a polymer lubricant containing a lubricant in the polymer, and the polymer lubricant is filled in such a manner that the outermost surface is exposed to the external gap, and the polymer lubricant is filled with the rolling element. The retainer is also used as a seal portion for preventing the liquid infiltrated from entering the rolling element housing space from the external gap.

  According to the above configuration, the outermost surface of the polymer lubricant filled in the rolling element housing space is exposed in the external gap, and the polymer lubricant closes a part of the external gap, so that the bearing outer space enters the bearing inside. It is possible to prevent muddy water and dust from entering.

  A thermoplastic resin may be used as the polymer of the polymer lubricant. According to this, the polymer lubricant can be heated to be in a molten state and filled in the rolling element housing space. Thereafter, by cooling, the polymer lubricant is solidified and serves as a seal portion.

  The first rolling element housing space forming portion is a first race ring member in which the first raceway surface forming portion and the outer gap forming portion are integrated, and the second rolling element housing space forming portion is the second raceway surface. It is a 2nd ring member with which the formation part and the formation part of the said external clearance were integrated.

  By forming an external gap between the first race ring member and the second race ring member, the first race ring member and the second race ring member can be rotated relative to each other via the rolling elements. Since the outermost surface of the polymer lubricant is exposed and filled in the external gap, it is possible to prevent muddy water and dust from entering the bearing from the outer space.

  Alternatively, the first rolling element housing space forming portion includes a first raceway having a first raceway surface and a first case formed as a separate body from the first raceway and coupled to the first raceway ring. And a second rolling element housing space forming portion includes a second raceway having a second raceway surface, and a second case formed as a separate body from the second raceway and coupled to the second raceway ring; And a thrust bearing in which an external gap is formed between the cases. In other words, the first case and the second case may be made of resin, and the first and second race rings may be made of steel and integrated by mount molding. In this case as well, the outermost surface of the polymer lubricant is exposed and filled in the external gap, so that muddy water, dust, and the like can be prevented from entering the bearing from the outer space.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the thrust ball bearing 1, and FIG. 2 is a cross-sectional view of a main part of the thrust ball bearing 1. The thrust ball bearing 1 is a first race ring member 3 including a first race ring member including a first rolling element housing space forming portion 5 and a second race ring member including a second rolling element housing space forming portion 15. The 2nd race part 4 and the some ball | bowl 2 as a rolling element arrange | positioned between the 1st race part 3 and the 2nd race part 4 are provided.

  The outer periphery of the first race portion 3 includes a first raceway surface forming portion 5a whose inner surface contacts the ball 2, and a first cylindrical portion extending from the first raceway surface forming portion 5a toward the second race portion 4 side. 6 is formed.

  On the inner side of the ball 2 side of the second race portion 4, a second raceway surface forming portion 15 a that is the raceway surface of the ball 2, and radially inward from the second raceway surface portion 15 a toward the first race portion 3 side. A second cylindrical portion 16 extending in a bent manner, bent toward the first race portion 3 side from the second raceway surface portion 15a to the outer peripheral portion of the second race portion 4, and restricts the movement of the ball 2 outward in the radial direction. A portion 17 is formed.

  The 1st race part 3 and the 2nd race part 4 are formed in an annular shape with steel materials. The plurality of balls 2 are arranged in a rolling element accommodation space 25 formed by the first race part 3 and the second race part 4 so as to be able to roll.

  The end surface 16s of the second cylindrical portion 16 of the second race portion 4 and the inner side surface 7s of the annular plate portion 7 of the first race portion 3 form an inner gap portion 20 as an outer gap.

  The rolling element housing space 25 is filled with a polymer lubricant 35 and serves as a cage. Further, the polymer lubricant 35 is also filled in a part of the inner gap 20 such that the outermost surface 35 a is exposed in the inner gap 20. Since the inner gap portion 20 is filled with the polymer lubricant 35, the solid polymer lubricant 35 functions as a seal portion that replaces the conventional elastic sealing material and the like, and the rolling element housing space 25 extends from the inner gap portion 20. It is possible to prevent muddy water and dust from passing to the side.

  Further, the inner diameter of the first cylindrical portion 6 is formed larger than the outer diameter of the bent portion 17 of the second race, and the inner peripheral surface 6s of the first cylindrical portion 6 end of the first race portion 3 and the second race portion. The outer peripheral surface 17s of the four bent portions 17 forms an outer clearance 21 as an external clearance.

  The polymer lubricant 35 is also filled in a part of the outer clearance 21 such that the outermost surface 35 b is exposed in the outer clearance 21. Since the outer gap portion 21 is filled with the polymer lubricant 35, the solid polymer lubricant functions as a seal portion that replaces the conventional elastic seal material and the like, and muddy water, dust, etc. It can prevent passing through the part 21 and entering the ball 2 side.

  The polymer lubricant 35 filled in the rolling element housing space, the inner gap and the outer gap contains a thermoplastic resin and 50 to 80% by weight of a lubricating oil (base oil) in the thermoplastic resin. It is. When the mixture of the thermoplastic resin and the lubricating oil is heated to a temperature equal to or higher than the melting point of the thermoplastic resin and then cooled, it becomes a solid lubricating composition. That is, it heats more than melting | fusing point of the said thermoplastic resin, fills the rolling element accommodation space 25 of a thrust bearing with the mixture in a fluid state, and cools. The solidified polymer lubricant 35 exhibits lubricity as a result of the lubricating component gradually oozing out due to heat or the like during use of the thrust ball bearing 1.

  As the thermoplastic resin, for example, ultrahigh molecular weight polyethylene, polyolefin, polypropylene, polymethylpentene, polyurethane and the like are used.

As the lubricating oil, any of synthetic oils such as poly-α-olefins, diesters, perfluoropolyethers, synthetic hydrocarbons, ether oils, ester oils, silicon oils, fluorine oils, and mineral oils can be used. The kinematic viscosity of these lubricating oil components is desirably 8 to 30 mm ² / S (stock) or more at 40 ° C.

  In addition, an extreme pressure additive and / or an antiwear agent is used in order to avoid a very heavy steering feeling and to prevent seizure of the friction surface in the bearing. Extreme pressure additives and / or antiwear agents include general organometallic complexes such as Mo dithiocarbamate and Zn dithiophosphate, sulfur compounds such as diester sulfide and benzyl sulfide, phosphorus such as tricresyl phosphate and phosphate ester. All extreme pressure additives and antiwear agents can be used, such as those based on halogenated systems such as chlorobenzene and alkylbenzene.

  Then, as described above, these fluid lubricants are mixed with powdered thermoplastic resin, further, an extreme pressure additive and an antiwear agent at a predetermined ratio, and heated to the melting point or higher to be plasticized. After being sealed in the gap in a state, it is cooled and solidified. The component of the thermoplastic resin is 10 to 90% by weight, and the lubricating oil composition is 90 to 10% by weight. This is because when the thermoplastic resin is 10% by weight or less, it does not solidify, and when the lubricating oil composition is 10 or less, the lubricating oil component does not sufficiently exude when solidified, resulting in poor lubricity. is there. The mixing ratio of the thermoplastic resin and the lubricating oil component is preferably 20 to 40% by weight for the thermoplastic resin and 80 to 60% by weight for the lubricating oil component. The extreme pressure additive and / or the antiwear agent is preferably blended in the range of 2 to 30% by weight (preferably 5 to 15% by weight) in the lubricating oil.

  When the polymer lubricant 7 is prepared, it can be melted and solidified using a combination of the above-mentioned various thermoplastic resins and lubricating oils. For example, the average molecular weight is about 1 million to 6 million, and the melting point is 100 ° C. A lubricating composition containing 20 to 80% by weight of ultrahigh molecular weight polyethylene at 140 ° C. (therefore, the lubricating oil is 80 to 20% by weight of any of the above) is melted, poured, and solidified by cooling. Can do.

  When the amount is less than 20% by weight, the lubricating composition is too soft and does not become a solid lubricant. On the other hand, if it exceeds 60% by weight, the lubricating composition is too hard and close to a resin, and the lubricating oil is less likely to ooze out and tends to cause poor lubrication.

  FIG. 3 shows an example of a strut suspension that is one of the suspension types of a vehicle in which the thrust ball bearing 1 of the present invention is incorporated. As shown in FIG. 3, the strut suspension is mounted on a support member 81 to support a part of the vehicle body, and is incorporated in the strut piston rod 83 to absorb vibrations and shocks from the tire side. A coil spring 82 and a stabilizer support 84 fixed to the upper part of the vehicle body are included.

  The strut type suspension is attached to a support member 81 on the vehicle body side and has a role of supporting the entire vehicle body in a floating manner with respect to an axle or the like. Around the support member 81, there are an axle 89, a hub 90 fixed to the axle 89 and mounted with wheels, a brake disc 91 fixed to the hub 90, and a pad that presses against the brake disc 91 by hydraulic pressure. A caliper body 92 provided inside is disposed.

  FIG. 4 shows an internal structure of an upper portion of a strut suspension (see FIG. 3) using the thrust ball bearing 1 having the above-described configuration. The strut suspension includes a coil spring seat 88 that holds a spring seat 87 of a coil spring 82, a thrust ball bearing 1 that is fitted to the upper end portion of a strut piston rod 83, and the thrust ball bearing at the upper portion of the thrust ball bearing 1. 1, a nut 86 for fixing 1, a stabilizer support 84 for holding the thrust ball bearing 1 so as to surround the thrust ball bearing 1, and the like. The stabilizer support 84 includes an elastic material 84a and an outer cylinder portion 84b that covers the periphery of the elastic material 84a.

  The thrust ball bearing 1 is disposed between the stabilizer support 84 and the coil spring seat 88. The coil spring seat 88 is an annular plate-like support that is supported on the lower surface of the outer peripheral portion 88a by the upper end portion of the spring seat 87 of the coil spring 82 of the suspension, and the thrust ball bearing 1 on the upper surface of the inner peripheral portion 88b. The second race portion 4 is supported. The first race portion 3 and the second race portion 4 rotate relative to each other.

  FIG. 5 shows another embodiment of the present invention. The thrust ball bearing 51 includes an upper case 53 that is a first case and a lower case 54 that is a second case. The upper case 53 and the lower case 54 are respectively formed with an annular upper race ring 55 and a lower race ring 56, and the upper case 53 is respectively provided above and below the balls 52, which are a plurality of rolling elements made of steel balls. An annular upper race 55 and a lower race 56 of the lower case 54 are supported. The upper case 53 and the lower case 54 are each formed of synthetic resin, and are formed by integrating an upper race ring 55 and a lower race ring 56 made of steel by mount molding.

  The upper and lower portions of the plurality of rolling elements 52 are supported by annular race portions 55 and 56 of the upper cover 53 and the lower cover 54, respectively. In the thrust ball bearing 51, protrusions 53a and 53b are formed on the inner peripheral edge and the outer peripheral edge of the upper cover 53 so as to project from the upper side to the lower side, and the inner peripheral edge and the outer peripheral edge of the lower cover 54 are formed. Projections 54a and 54b projecting in a cylindrical shape from the bottom to the top are also formed in the part. And the protrusion part 54a of the inner peripheral part of the lower cover 54 fits in the outer peripheral side from the protrusion part 53a of the inner peripheral part of the upper cover 53 with a gap 57, and from the protrusion part 53b of the outer peripheral part of the upper cover 3. A protrusion 54b at the outer peripheral edge of the lower cover 54 is fitted on the inner peripheral side with a gap 58 therebetween.

The rolling element housing space 59 is filled with the polymer lubricant 35, and the polymer lubricant 35 has its outermost surfaces 55 a and 55 b exposed in the gaps 57 and 58. Thereby, like the above-mentioned Example, it can prevent that liquid infiltrates, such as muddy water, permeate into the rolling element accommodation space 59 from the bearing outer space by the polymer lubricant.

  The present invention is not limited to thrust ball bearings, and can be applied to general thrust bearings used for strut suspensions.

Sectional drawing of a thrust ball bearing. The principal part expanded sectional view of the thrust ball bearing of FIG. The perspective view which shows the strut type suspension of a vehicle. Sectional drawing of the principal part of a strut type suspension. Sectional drawing of the thrust ball bearing as another Example. Sectional drawing of the conventional thrust ball bearing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thrust ball bearing 2 Ball 3 1st race part 4 2nd race part 5 1st rolling element accommodation space formation part 15 2nd rolling element accommodation space formation part 20 Inner clearance part 21 Outer clearance part 25 Rolling element accommodation space 35 Polymer lubrication Agents 35a, 35b Outermost surface 51 Thrust ball bearing 52 Ball 53 Upper case 54 Lower case 57, 58 Clearance

Claims (2)

A thrust bearing supported by a coil spring seat and an upper portion of a strut piston rod, wherein one of the race rings is fixed to the strut piston rod;
A first rolling element housing space forming section that has a first raceway surface forming section that supports a plurality of rolling elements from an axial direction, and that forms a rolling element housing space that houses the rolling elements;
A second raceway surface forming portion that supports the rolling element facing the first raceway surface forming portion in an axial direction, and forms the rolling body housing space together with the first rolling body housing space forming portion; A rolling element housing space forming part,
The first rolling element accommodation space forming portion and the second rolling element accommodation space forming portion are arranged to face each other in a form that forms an external gap communicating with the rolling element accommodation space outside the rolling element accommodation space,
The rolling element housing space is filled with a polymer lubricant containing a lubricant in a polymer, and the polymer lubricant is filled such that the outermost surface is exposed in the external gap, and the polymer lubricant is A thrust bearing characterized by being used both as a rolling element retainer and a seal portion for preventing liquid intrusion from entering the rolling element housing space from the external gap. The thrust bearing according to claim 1, wherein the polymer of the polymer lubricant is a thermoplastic resin.

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