JPH08159160A - Synthetic resin thrust bearing - Google Patents

Abstract

PURPOSE: To properly maintain a clearance between a fitting part, overlapped part and a piston rod, by elastically fitting a cylinder engaging suspension part of an upper bearing case to a cylinder engaging protruded part of a lower bearing case, overlapping the cylnder suspension part with the cylinder protruded part, and forming bearing piece both end faces into a truncated cone surface. CONSTITUTION: In an upper bearing case C, engaging surface 59, 60 of a cylinder engaging suspension part 61 are elastically fitted to engaging surfaces 44, 45 of a cylinder engaging protruded part 46 of a lower bearing case B, and a cylinder suspension part 57 is engaged with an annular shoulder part 38 of the lower bearing case B, to overlap an end part of the cylinder suspension part 57 in a diametric direction with an end part of a cylinder protruded part 40 of the lower bearing case B, so as to form a seal part of performing labyrinth action in an elastic fitting part and an overlapped part. End faces 71, 72 of a bearing piece D are formed in a truncated cone surface provided with an ascending gradient of the same slope to bottom surfaces 47, 64 which are a truncated cone surface of annular recessed parts 42, 63. In this way, force of tending to move with a piston rod serving as the center acts in a bearing, to automatically perform centering, and a clearance between the elastic fitting part, overlapped part and the pision rod in maintained in a proper value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin thrust bearing, and more particularly to a synthetic resin thrust bearing suitable for being incorporated in a strut thrust type suspension (McPherson type) in a four-wheeled vehicle.

[0002]

2. Description of the Related Art Generally, strut suspensions are
This suspension is mainly used for the front wheels of four-wheeled vehicles, and is a suspension that combines a coil spring with a strut assembly that incorporates a hydraulic shock absorber in an outer cylinder that is integrated with the main shaft. In this suspension, when the strut assembly rotates with the coil spring by steering operation, the piston rod of the assembly,
In some types, a bearing is arranged between the mounting member of the vehicle body and the upper spring seat of the coil spring in order to allow the rotation of the strut assembly smoothly.

Conventionally, as the bearing at this location, a rolling bearing using balls or a sliding bearing made of synthetic resin has been used. However, the roller bearing has a problem that it is difficult to maintain a smooth steering operation for a long period of time because there is a possibility that the ball may be fatigue-damaged by a minute vibration, a vibration load, or the like. Further, the sliding bearing made of a synthetic resin has a higher friction coefficient than the roller bearing, which causes a problem of making the steering operation heavy. Furthermore, in all bearings, a dust seal made of a rubber elastic body is mounted between the relative rotating surfaces in order to prevent foreign matter such as dust from entering the sliding surface. Therefore, there is a problem that the sliding frictional force is high at the time of steering operation and the steering becomes heavy, and particularly the sliding bearing made of synthetic resin has a problem that the steering becomes heavier.

In order to solve the above-mentioned problems of the plain bearing made of synthetic resin in the prior art, the present applicant has previously
For example, Japanese Patent Application No. 61-196803 (Japanese Utility Model 2-153)
No. 2), Japanese Utility Model Application No. 61-196804 (Actual Fairness 2-62)
63), Jpn. App. No. 1-16171 (Jpn. Pat. Appl. 2-107)
No. 823), a synthetic resin thrust bearing that can prevent foreign matter such as dust from entering the sliding surface without using a dust seal made of a rubber elastic body and prevent an increase in steering force during steering operation is proposed.

The technique proposed in Japanese Utility Model Application No. 61-196804 (Japanese Utility Model Publication No. 2-6263) will be described with reference to FIG. The synthetic resin thrust bearing A shown in FIG.
It is composed of a synthetic resin lower case B, a synthetic resin upper case C, and an annular plate-shaped synthetic resin bearing piece D, and the synthetic resin lower case B has an annular plate-shaped base portion having an insertion hole 1 in the center. 2, a cylindrical portion 4 projecting from the lower surface of the base portion 2 and having an insertion hole 3 coaxial with the insertion hole 1 and having the same diameter, and a base portion having an annular shoulder portion 5 radially outward of the insertion hole 1. 2, a cylindrical protrusion 6 protruding from the upper surface, an annular lower lip portion 8 which cooperates with the cylindrical protrusion 6 to form an annular recess 7 on the radially outer side and protrudes from the upper surface of the base portion 2, and an annular lower lip portion. 8 has an annular groove 9 in cooperation with it, has an engaging surface 11 on the outer peripheral surface, and is provided with an annular engaging protrusion 10 formed on the outer peripheral edge of the base portion 2. C is the insertion hole 1 in the center
An annular plate-shaped base portion 13 that has an insertion hole 12 that is coaxial with and has the same diameter, and an annular hanging portion 14 that is provided on a lower surface of the base portion 13 and that has an insertion hole 12a that is coaxial with and has the same diameter as the insertion hole 12.
And the annular concave groove 15 radially outward with respect to the annular hanging portion 14.
An annular upper lip portion 16 that forms and hangs down, and an annular groove 17 is formed radially outward in cooperation with the annular upper lip portion 16.
Further, it has an engaging hook surface 19 on the inner peripheral surface and an annular engaging hanging portion 18 formed on the outer peripheral edge of the base portion 13, and the synthetic resin bearing piece D is a cylindrical protrusion of the lower case B. Part 6
Having an inner diameter larger than the outer diameter of the lower case B and an outer diameter smaller than the inner diameter of the lower annular lip portion 8 of the lower case B, the lower surface of the annular recess 7 of the lower case B is the bottom surface of the recess 7 and the upper surface thereof is the upper case. The upper case C is slidably disposed on the bottom surface of the annular recess 15 of the C, and the upper case C has the engaging hook surface 19 of the annular engaging hanging portion 18 on the engaging surface 11 of the annular engaging protrusion 10 of the lower case B. It is elastically fitted and has an annular hanging portion 14 of the upper case C.
To the annular shoulder portion 5 of the lower case B, the annular upper lip portion 16 to the annular groove 9 of the lower case B, and the end portions of the annular hanging portion 14 and the annular upper lip portion 16 to the cylindrical protrusion 6 and the annular portion of the lower case B, respectively. The elastic fitting portion and both overlapping portions are formed with a sealing portion by a labyrinth action so as to be overlapped with each other at the end portion of the lower lip portion 8 in the radial direction so as to be relatively rotatable.

[0006]

As shown in FIG. 11, the synthetic resin thrust bearing A having the above-mentioned structure has a lower case in which the piston rod R of the strut is inserted into the insertion holes 1, 3, 12 and 12a. B and the upper case C are attached to the outer peripheral surface of the piston rod R, and the cylindrical portion 4 of the lower case B is attached.
The outer peripheral surface is fitted and fixed to the hole S1 of the upper spring seat S, the lower surface of the base portion 2 of the lower case B is brought into contact with the flat surface portion S2 of the spring seat S, and the upper surface of the base portion 13 of the upper case C is attached to the vehicle body side. It is placed between the upper spring seat S and the vehicle body mounting member F while being brought into contact with the lower surface of the mounting member F. As described above, in the synthetic resin thrust bearing A arranged between the upper spring seat S and the vehicle body side mounting member F, in order to maintain a smooth steering operation, upper and lower cases C and B are provided.
It is preferable that an appropriate gap be maintained between the elastic fitting portion, each overlapping portion, and the piston rod R.

However, one member on which the synthetic resin thrust bearing A is arranged, that is, the upper spring seat S is unstable because it is supported by the coil spring D, and as shown in FIG. During assembly,
When relative displacement occurs in the horizontal direction between the upper spring seat S and the vehicle body side mounting member F, in the synthetic resin thrust bearing A disposed between the two, the upper case C and the lower case B are separated from each other. A relative displacement is generated in the horizontal direction, and the elastic fitting portions of the upper and lower cases C and B, the overlapping portions, and the piston rod R
A proper gap cannot be maintained between the elastic fitting portion, the overlapping portions and the piston rod R, or a large gap is generated in the elastic fitting portion, resulting in a bearing. This causes problems such as hindering smooth relative rotation between the upper and lower cases C and B via the piece D and facilitating entry of foreign matter such as dust into the sliding surface. Even if the synthetic resin thrust bearing A is assembled in the normal position between the upper spring seat S and the vehicle-side mounting member F, such a problem is caused by a lateral load (side hose) on the strut assembly during use. ), There is still a relative displacement between the upper spring seat S and the vehicle body side mounting member F in the horizontal direction,
It appears as a problem similar to the above.

The present invention has been made in view of the above problems, and an object of the present invention is to obtain a synthetic resin thrust bearing which can always maintain a proper gap between the elastic fitting portion, each overlapping portion and the piston rod. It is a thing.

[0009]

According to the present invention, the above-mentioned object is to provide an upper bearing base portion, a cylindrical hanging portion that hangs from the lower surface of the upper bearing base portion on the annular inner peripheral side, and an upper portion in cooperation with the cylindrical hanging portion. An upper bearing made of synthetic resin, which has a cylindrical engaging hanging portion that hangs with an engaging surface from an annular outer peripheral lower surface of the upper bearing base portion to an inner peripheral surface so as to define an annular recess on the lower surface side of the upper bearing base portion. A cylindrical protrusion that projects from the upper surface of the lower bearing base by forming an annular shoulder on the upper surface of the lower bearing base between the case, the lower bearing base, and the annular inner peripheral surface of the lower bearing base. And a cylindrical engaging member projecting with an engaging surface from the annular outer peripheral surface of the lower bearing base portion so as to define the lower annular recess on the upper surface side of the lower bearing base portion in cooperation with the outer peripheral surface of the cylindrical protruding portion. Synthetic resin lower bearing case with mating protrusion and upper part And a synthetic resin bearing piece disposed in the lower annular recess, and the upper bearing case has an engaging surface of a cylindrical engaging hanging portion elastically fitted to an engaging surface of a cylindrical engaging protrusion of the lower bearing case. Then, the cylindrical hanging part is engaged with the annular shoulder part of the lower bearing case, and the end of the cylindrical hanging part is radially overlapped with the end of the cylindrical protruding part so that a labyrinth action is exerted on the elastic fitting part and the overlapping part. And a bottom face of the upper and lower annular recesses and both end faces of the bearing piece slidably in contact with the bottom face are each formed into a truncated cone surface. It is achieved by a synthetic resin thrust bearing.

Further, in the above structure, the lower surface of the upper bearing base portion in the upper annular recess is provided with an annular groove on the one hand in cooperation with the cylindrical engaging hanging portion, and on the other hand, an upper inner annular recess in cooperation with the cylindrical hanging portion. Outer annular hanging parts that respectively define and hang down are further formed, and in the lower annular concave portion, on the upper surface of the lower bearing base portion, on the one hand, an annular groove in cooperation with the cylindrical engaging protrusion, and on the other hand, Outer annular protrusions are further formed that cooperate with the cylindrical protrusions to define and protrude lower inner annular recesses, respectively, and the upper bearing case has an end of the outer annular hanging portion and an outer annular protrusion of the lower bearing case. It is also possible to form a synthetic resin thrust bearing which is formed by being overlapped with the end portion of the protruding portion in the radial direction and forming a sealing portion by a labyrinth action in the overlapping portion so as to be combined with the lower bearing case.

Further, in the above-mentioned structure, the lower surface of the upper bearing base portion in the upper annular recess is provided with an outer annular hanging portion that cooperates with the cylindrical engaging hanging portion to define an upper outer annular groove and hangs down. Further, an inner inner hanging portion is further formed which cooperates with the hanging portion to define an upper inner annular groove and, on the other hand, cooperates with the outer annular hanging portion to define and hang down an upper intermediate annular recess, respectively. On the upper surface of the lower bearing base portion in the recess, an outer annular protrusion that cooperates with the cylindrical engagement protrusion to define and protrudes a lower outer annular groove, and on the other hand, cooperates with the cylindrical protrusion to form a lower inner annular groove. On the other hand, an inner ring-shaped protrusion that cooperates with the outer ring-shaped protrusion and defines and projects a lower intermediate ring-shaped recess is further formed, and the upper bearing case includes an end portion of the inner ring-shaped hanging part and an outer side. Each end of the circular hanging part The end portion of the side annular protrusion and the end portion of the outer annular protrusion are radially overlapped with each other to form a sealing portion by a labyrinth action in the overlapping portion, and the sealing portion is combined with the lower bearing case. It is also possible to use the described synthetic resin thrust bearing.

In any of the above-mentioned configurations, the bottom surfaces of the upper and lower annular recesses and the both end surfaces of the bearing piece slidably contacting the bottom surfaces each have an upward slope from the inner diameter side to the outer diameter side. It may be formed on the frusto-conical surface or on the frusto-conical surface having a downward slope from the inner diameter side to the outer diameter side, respectively.

In the synthetic resin thrust bearing having the above structure, the synthetic resin forming the upper and lower bearing cases preferably has excellent mechanical properties such as wear resistance, impact resistance, and creep resistance. Further, the synthetic resin bearing pieces arranged on the upper and lower bearing case sides are particularly preferably those having self-lubricating properties, such as polyacetal resin,
Polyamide resin, polybutylene terephthalate (PB
A thermoplastic polyester resin such as T) or a polyolefin resin such as polyethylene or polypropylene is preferably used.

For the upper and lower bearing cases, the same synthetic resin as the above bearing piece is used. In particular, it is a combination of the synthetic resin used for the bearing piece and good friction characteristics, and a comparison is made. It is desirable that the synthetic resin has a high mechanical rigidity,
A polyacetal resin or a polyamide resin is preferably used.

[0015]

In the synthetic resin thrust bearing of the present invention,
Since the mutual sliding surface between the upper and lower bearing cases and the bearing piece is formed as a frusto-conical surface, it is also used during assembly between the upper spring seat and the vehicle body side mounting member. Also in the above, the synthetic resin thrust bearing is subjected to a force to move to the center of the piston rod, and the centering of the synthetic resin thrust bearing is automatically performed. Therefore, the gap between the elastic fitting portion of the upper bearing case and the lower bearing case, each overlapping portion, and the piston rod is always maintained at an appropriate gap.

The present invention will be described below in detail with reference to the accompanying drawings showing specific examples thereof. The present invention is not limited to these specific examples.

[0017]

SPECIFIC EXAMPLE In FIG. 1, a synthetic resin thrust bearing A of this example is a synthetic resin lower bearing case B, a synthetic resin upper bearing case C, and a synthetic resin bearing piece D arranged between upper and lower bearing cases C and B. It consists of and.

The bearing case B has an annular plate-shaped base portion 3 having an annular inner peripheral surface 32 defining an insertion hole 31 at the center thereof.
3 and the bottom surface 34 of the base portion 33 so as to project from the insertion hole 31.
A cylindrical portion 37 having an annular inner peripheral surface 36 which is continuous with the inner peripheral surface 32 and defines an insertion hole 35 having the same diameter and the same diameter as that of the inner peripheral surface 32; A cylindrical protrusion 40 that is formed from the upper surface 39 of the base 33 to form an annular shoulder 38 between the cylindrical protrusion 40 and the outer peripheral surface 41 of the cylindrical protrusion 40.
And a cylindrical engaging protrusion 46 protruding from the annular outer peripheral surface of the base portion 33 to the outer peripheral surface 43 with engaging surfaces 44 and 45 so as to define the lower annular recess 42 on the upper surface 39 side of the base portion 33 in cooperation with And the outer peripheral surface 41 of the cylindrical protrusion 40.
The bottom surface 47 of the annular recess 42 defined by the upper surface 39 of the base portion 33 and the inner peripheral surface 48 of the cylindrical engaging protrusion 46 extends from the base of the cylindrical protruding portion 40 toward the base of the cylindrical engaging protrusion 46. It is formed on a frusto-conical surface that makes an upward slope. The bottom surface 47 forming the truncated conical surface of the annular recess 42 serves as the sliding surface of the lower bearing case B. The outer peripheral surface 41 of the cylindrical protruding portion 40 formed so as to protrude from the upper surface 39 of the base portion 33 has an annular recess 42.
Is formed as a wall surface orthogonal to the bottom surface 47 that is a truncated cone surface, and the inner peripheral surface 48 of the cylindrical engagement protrusion 46 is also formed as a wall surface that is orthogonal to the bottom surface 47 that is a truncated cone surface of the annular recess 42. Has been done. The engagement surface 44 formed on the outer peripheral surface 43 of the cylindrical engagement protruding portion 46 is an inclined surface that extends downward from the end of the outer peripheral surface 43, and the engagement surface 45 is the engagement surface 44.
And the engaging surface 44 and the annular convex corner portion are connected to the base portion 33.
Are connected to the outer peripheral surface of.

The upper bearing case C has an annular plate-like base portion 53 having an inner peripheral surface 52 defining a through hole 51 having the same diameter as the through holes 31 and 35 of the lower bearing case B in the center portion, and a base portion. 53, and the insertion hole 51.
A cylindrical hanging portion 57 having an annular inner peripheral surface 56 that is continuous with the inner peripheral surface 52 and defines an insertion hole 55 that is coaxial with and has the same diameter, and an engaging surface 59 from the lower surface 54 of the base portion 53 to the inner peripheral surface 58. And 6
It is provided with a cylindrical engaging hanging portion 61 which hangs at 0 and cooperates with the outer peripheral surface 62 of the cylindrical hanging portion 57 to define an annular recess 63. The outer peripheral surface 62 of the cylindrical hanging portion 57 and the base portion 5 are provided.
The bottom surface 64 of the annular concave portion 63 defined by the lower surface 54 of the cylindrical engagement hanging portion 61 and the inner peripheral surface 58 of the cylindrical engagement hanging portion 61 extends from the base portion of the cylindrical hanging portion 57 toward the base portion of the cylindrical engaging hanging portion 61. It is formed in a frusto-conical surface which has the same inclination as the bottom surface 47 which is the frusto-conical surface of the annular recess 42 of B and which has the same inclination. The frusto-conical surface of the bottom surface 64 of the annular recess 63 is the upper bearing case C.
It becomes the sliding surface of. The engagement surface 59 formed on the inner peripheral surface 58 of the cylindrical engagement hanging portion 61 is an inclined surface corresponding to the engagement surface 44 of the cylindrical engagement protrusion 46 of the lower bearing case B, and the engagement surface 60 is Is an inclined surface corresponding to the engagement surface 45 of the cylindrical engagement protrusion 46, which forms an annular angular recess in succession to the engagement surface 59.

The upper bearing case C includes a cylindrical engaging hanging portion 61.
Engagement surfaces 59 and 60 of the lower bearing case B are elastically fitted (snap-fitted) to the engagement surfaces 44 and 45 of the cylindrical engagement protrusion 46 of the lower bearing case B, and the cylindrical hanging portion 57 is formed into the annular shoulder portion 38 of the lower bearing case B. And the end portion of the cylindrical hanging portion 57 is radially overlapped with the end portion of the cylindrical protruding portion 40 of the lower bearing case B, and is rotatably combined with the lower bearing case B. With this combination, the upper bearing case C
The elastic fitting portions of the engaging surfaces 59 and 60 of the cylindrical engaging hanging portion 61 and the engaging surfaces 44 and 45 of the cylindrical engaging protruding portion 46 of the lower bearing case B, the cylindrical hanging portion 57 and the cylindrical protruding portion 40. A sealing portion having a labyrinth action is formed in the overlapping portion with the.

Between the upper and lower bearing cases C and B, the synthetic resin bearing piece D disposed in the annular recesses 42 and 63 has an inner diameter larger than the outer diameter of the cylindrical protrusion 40 of the lower bearing case B. And has a ring shape having an outer diameter smaller than the inner diameter of the cylindrical engaging protrusion 46, and both end surfaces 7 of the bearing piece D.
Nos. 1 and 72 are formed from the inner diameter side to the outer diameter side on the frustoconical surface having the same slope as the bottom surfaces 47 and 64 which are the frustoconical surfaces of the annular recesses 42 and 63, and both end surfaces 71 As shown in FIG. 2, the ring grooves 73 and 74 and the one ends have ring grooves 73 and
4, a plurality of grooves 7 that communicate with each other and open at the other end to the outer diameter side.
5 are radially formed with a phase difference of 30 degrees in the circumferential direction. The ring grooves 73 and 74 and the radial grooves 75 and 76 serve as a reservoir for a lubricant such as grease. Bearing piece D
The upper and lower bearing cases C and B by slidably abutting both end surfaces 71 and 72 which are frusto-conical surfaces to the bottom surfaces 47 and 64 which are frusto-conical surfaces of the annular recesses 42 and 63, respectively. Both end surfaces 71 and 72 and the bottom surfaces 47 and 64 of the bearing piece D, which are arranged between the two, serve as sliding surfaces.

The synthetic resin thrust bearing A thus constructed is incorporated in the strut assembly shown in FIG. That is, the bearing A has the insertion holes 31, 35, 51 and 55.
The piston rod R of the strut assembly is inserted through the outer peripheral surface of the piston rod R and the inner peripheral surfaces 32, 36, 52 and 56 while maintaining a bearing clearance (clearance). The outer peripheral surface 81 of 37 is fitted and fixed to the hole S1 of the upper spring seat S, and the lower surface 34 of the base portion 33 is fixed to the flat surface S2 of the upper spring seat S.
The upper surface 82 of the base portion 53 of the upper bearing case C.
Is brought into contact with the lower surface of the vehicle body side mounting member F, and is disposed between the upper spring seat S and the vehicle body side mounting member F.

When arranging the bearing A between the upper spring seat S and the vehicle body side mounting member F, the upper spring seat S
Even if horizontal relative displacement occurs between the vehicle body side mounting member F and the vehicle body side mounting member F, in the bearing A, the sliding surfaces of the upper and lower bearing cases C and B and the bearing piece D have annular recesses. Bottom surfaces 47 and 64 which are truncated cone surfaces of 42 and 63
And both end surfaces 71 and 72 which are frustoconical surfaces of the bearing piece D, the fastening force of the nut N acts on the bearing A toward the center of the piston rod R, and the centering of the bearing A is performed. Is done automatically. Therefore, the displacement between the upper bearing case C and the lower bearing case B caused by the relative displacement between the upper spring seat S and the vehicle body side mounting member F is corrected, and the elastic fitting between the upper and lower bearing cases C and B is corrected. Since an appropriate gap is secured between the fitting portion, the overlapping portion and the piston rod, the upper bearing case C via the bearing piece D is provided.
The relative rotation between the lower bearing case B and the lower bearing case B is smoothly performed. Further, when a lateral load is applied in a state where the bearing A is assembled between the upper spring seat S and the vehicle body side mounting member F in a normal positional relationship, the upper spring seat seat S and the vehicle side mounting member F are connected to each other. However, as described above, the bearing A acts to move to the center of the piston rod R, and the centering of the bearing A is automatically performed. An appropriate gap is secured between the elastic fitting portion with the cases C and B, the overlapping portion, and the piston rod.

Next, another embodiment of the present invention will be described with reference to FIG. 4, in the synthetic resin thrust bearing A of the present example, the upper surface 3 of the base portion 33 in the annular recess 42 of the lower bearing case B is the same as the synthetic resin thrust bearing described above.
9, on the one hand, an outer annular groove 92 which cooperates with the cylindrical engagement projection 46 to define an outer annular groove 91 and, on the other hand, with the cylindrical projection 40 to define and project a lower inner annular recess 42a. Is further formed, and the bottom surface 47a of the annular recess 42a extends from the base of the cylindrical protrusion 40 to the outer annular protrusion 9a.
It is formed on a truncated cone surface that has an upward slope toward the base of 2. Bottom surface 47a which is a truncated cone surface of the annular recess 42a
Is the sliding surface of the lower bearing case B. The outer peripheral surface 41 of the cylindrical protrusion 40 is a wall surface orthogonal to the bottom surface 47a of the annular recess 42a, and the outer annular protrusion 9 as in the specific example.
Similarly, the inner peripheral surface 93 of No. 2 has a bottom surface 47 of the annular recess 42a.
It is formed as a wall surface orthogonal to a.

In the annular recess 63 of the upper bearing case C, on the lower surface 54 of the base portion 53, on the one hand, the annular groove 100 is cooperated with the cylindrical engaging hanging portion 61, and on the other hand, the cylindrical hanging portion 57 is cooperated. Further, outer annular hanging portions 101 that respectively define and hang down the upper inner annular concave portions 63a are further formed, and the bottom surface 64a of the annular concave portions 63a has a cylindrical hanging portion 57.
From the base portion of the outer circular hanging portion 101 to the base portion of the outer circular hanging portion 101 is formed into a truncated conical surface. Annular recess 63a
The bottom surface 64a forming the truncated cone surface of the upper bearing case C
It becomes the sliding surface of.

The upper bearing case C configured as described above
Are the engaging surfaces 59 and 60 of the cylindrical engaging hanging portion 61 and the engaging surfaces 44 and 45 of the cylindrical engaging protrusion 46 of the lower bearing case B.
And the cylindrical hanging part 57 is engaged with the annular shoulder 38 of the lower bearing case B, and the end of the cylindrical hanging part 57 and the end of the outer annular hanging part 101 are respectively projected into the cylindrical shape of the lower bearing case B. End of portion 40 and outer annular protrusion 92
Is superposed in the radial direction with the end of the above, and a sealing portion by a labyrinth action is formed in the elastic fitting portion and each overlapping portion, and is combined with the lower bearing case B.

The bearing piece D has a ring shape having an inner diameter larger than the outer diameter of the cylindrical protrusion 40 of the lower bearing case B and an outer diameter smaller than the inner diameter of the outer annular protrusion 92. Both end surfaces 71 and 72 are formed in a frusto-conical surface having the same inclination as the bottom surfaces 47a and 64a forming the frusto-conical surfaces of the annular recesses 42a and 63a from the inner diameter side toward the outer diameter side. ing. The bearing piece D is disposed between the upper and lower bearing cases C and B by slidably abutting both end surfaces 71 and 72 thereof on the bottom surfaces 47a and 64a of the annular recesses 42a and 63a, respectively. Both end surfaces 71 and 72 of D and the bottom surfaces 47a and 64a are sliding surfaces. In this example, the synthetic resin thrust bearing in the above-mentioned specific example has a double sealing portion by the labyrinth action on the outer peripheral surface side, and the sealing performance against foreign matter such as dust entering from the outer peripheral surface side to the sliding surface. It is a heightened one.

FIG. 5 shows still another embodiment of the present invention. 5, in the synthetic resin thrust bearing A of the present example, in the synthetic resin thrust bearing having the above-described configuration, the upper surface 39 of the annular recess 42 of the base portion 33 of the lower bearing case B is
An outer annular protrusion 92b that cooperates with the cylindrical engagement protrusion 41 to define and protrude a lower outer annular groove 91b;
Further formed is a lower inner annular groove 110 in cooperation with the cylindrical protrusion 40 and, on the other hand, an inner annular protrusion 111 which cooperates with the outer annular protrusion 92b to define and protrude a lower intermediate annular recess 42b. , The bottom surface 47b of the annular recess 42b
Is the outer annular protrusion 9 from the base of the inner annular protrusion 111.
It is formed into a truncated cone surface that has an upward slope toward the base of 2b. A bottom surface 47 which is a truncated cone surface of the annular recess 42b.
b is the sliding surface of the lower bearing case B. The outer peripheral surface 112 of the inner annular protruding portion 111 formed so as to protrude from the upper surface 39 of the base portion 33 serves as a wall surface orthogonal to the bottom surface 47b of the annular recess 42b, and the inner peripheral surface 93b of the outer annular protruding portion 92b.
Are similarly formed as wall surfaces orthogonal to the bottom surface 47b of the annular recess 42b.

On the lower surface 54 of the upper annular recess 63 of the base portion 53 of the upper bearing case C, an outer annular hanging portion 101b which cooperates with the cylindrical engaging hanging portion 61 to define an upper outer annular groove 100b and hangs down. On the one hand, in cooperation with the cylindrical hanging part 57, the upper inner annular groove 121, and on the other hand, cooperating with the outer annular hanging part 101b, the upper intermediate annular recess 63.
And a bottom surface 64b of the annular recess 63b has a truncated conical surface that has an upward slope from the base of the inner annular hanging portion 122 to the base of the outer annular hanging portion 101b. Is formed in. The bottom surface 64b of the annular recess 63b serves as the sliding surface of the upper bearing case C.

The upper bearing case C configured as described above
Are the engaging surfaces 59 and 60 of the cylindrical engaging hanging portion 61 and the engaging surfaces 44 and 45 of the cylindrical engaging protrusion 46 of the lower bearing case B.
And the cylindrical hanging part 57 is engaged with the annular shoulder portion 38 of the lower bearing case B, and the end of the cylindrical hanging part 57, the end of the inner annular hanging part 122 and the outer annular hanging part 1 are fitted.
01b of the lower bearing case B is radially overlapped with the end of the cylindrical protrusion 40, the end of the inner annular protrusion 111, and the end of the outer annular protrusion 92b, respectively, and the elastic fitting portion and each overlap are overlapped. A sealing portion by a labyrinth action is formed in the portion and is combined with the lower bearing case B.

The bearing piece D has a ring shape having an inner diameter larger than the outer diameter of the inner annular protrusion 111 of the lower bearing case B and an outer diameter smaller than the inner diameter of the outer annular protrusion 92b. Both end faces 71 and 72 of D are formed into a truncated conical surface that has the same upward slope as the bottom faces 47b and 64b from the inner diameter side toward the outer diameter side. The bearing piece D has bottom surfaces 47b and 64 on both end surfaces 71 and 72 thereof.
b is slidably brought into contact with each other and is arranged between the upper and lower bearing cases C and B.
And 72 and the bottom surfaces 47b and 64b serve as sliding surfaces. In this specific example, the synthetic resin thrust bearing in the above-described specific example has double sealed portions by labyrinth action on the inner peripheral surface side and the outer peripheral surface side, respectively. It has improved sealing performance against foreign matter such as dust.

FIGS. 6, 7 and 8 further show another embodiment of the present invention. The synthetic resin thrust bearing A of FIG. 6 is the same as the synthetic resin thrust bearing shown in FIG. 1 described above, except that the bottom surface 47 of the annular recess 42 of the lower bearing case B extends from the base of the cylindrical protrusion 40 to the cylindrical engagement protrusion 46. It is formed on the frusto-conical surface that has a downward slope toward the base, and the upper bearing case C
The bottom surface 64 of the annular recess 63 is formed as a truncated conical surface having a downward slope from the base portion of the cylindrical hanging portion 57 toward the base portion of the cylindrical engaging hanging portion 61. In the bearing piece D, both end surfaces 71 and 72 are formed into a truncated conical surface having a downward slope of the same inclination as the bottom surfaces 47 and 64 from the inner diameter side to the outer diameter side, respectively. Then, the bearing piece D has both end faces 7
1 and 72 are slidably brought into contact with the bottom surfaces 47 and 64, respectively, and are arranged between the upper and lower bearing cases C and B, and both end surfaces 71 and 72 of the bearing piece D and the bottom surfaces 47 and 64 are provided. Is the sliding surface.

The synthetic resin thrust bearing A shown in FIG. 7 is the same as the synthetic resin thrust bearing shown in FIG. 4, except that the bottom surface 47a of the annular recess 42a of the lower bearing case B extends from the base of the cylindrical projection 40 to the outer annular projection. It is formed in a truncated conical surface that has a downward slope toward the base of 92, and the bottom surface 64a of the annular recess 63a of the upper bearing case C descends from the base of the cylindrical hanging part 57 toward the base of the outer annular hanging part 101. It is formed on a frusto-conical surface that forms a slope. In the bearing piece D, the end surfaces 71 and 72 are formed into a truncated conical surface having a downward slope with the same inclination as the bottom surfaces 47a and 64a from the inner diameter side toward the outer diameter side, respectively. And the bearing piece D is
Both end faces 71 and 72 are slidably brought into contact with the bottom faces 47a and 64a, respectively, and are arranged between the upper and lower bearing cases C and B. And 64a serve as sliding surfaces.

The synthetic resin thrust bearing A shown in FIG. 8 is the same as the synthetic resin thrust bearing shown in FIG. 5, except that the bottom surface 47b of the annular recess 42b of the lower bearing case B projects from the base of the inner annular projection 111 to the outer annular projection. The frusto-conical surface that forms a downward slope toward the base of the portion 92b, and the bottom surface 64b of the annular recess 63b of the upper bearing case C is directed from the base of the inner annular hanging portion 122 to the base of the outer annular hanging portion 101b. It is formed on the frusto-conical surface that forms a downward slope.

In the bearing piece D, both end surfaces 71 and 72 are bottom surfaces 47b and 64 from the inner diameter side to the outer diameter side, respectively.
It is formed on a frusto-conical surface having the same downward slope as b. Then, the bearing piece D has its both end surfaces 71 and 72,
The bottom surfaces 47b and 64b are slidably brought into contact with each other and arranged between the upper and lower bearing cases C and B, and both end surfaces 71 and 72 of the bearing piece D and the bottom surfaces 47b and 64b serve as sliding surfaces. .

In the synthetic resin thrust bearing shown in FIGS. 1 and 4 to 8 described above, the inner peripheral surface defining the insertion hole 35 having the same diameter as the insertion hole 31 on the lower surface of the base portion 33 of the lower bearing case B. Although the example in which the cylindrical portion 37 having the protrusion 36 is provided is shown, as shown in FIG. 9, the base portion 3 of the lower bearing case B is shown.
The lower surface of the lower bearing case B may have a flat shape without projecting the cylindrical portion 37 on the lower surface of 3.

[0037]

As described above, according to the synthetic resin thrust bearing of the present invention, the sliding surfaces of the upper and lower bearing cases and the bearing pieces have a truncated slope with an upward slope from the inner diameter side to the outer diameter side. Since it is formed on the conical surface or on the frusto-conical surface with a downward slope from the inner diameter side to the outer diameter side, it can be used even when assembled between the upper spring seat and the vehicle body side mounting member. Also, in the synthetic resin thrust bearing, the force to move to the center of the piston rod acts,
Centering of synthetic resin thrust bearings is performed automatically. Therefore, the gap between the elastic fitting portion of the upper bearing case and the lower bearing case, each overlapping portion, and the piston rod is always maintained at an appropriate gap.

[Brief description of drawings]

FIG. 1 is a sectional view of a synthetic resin thrust bearing of the present invention.

FIG. 2 is a plan view of a bearing piece in the synthetic resin thrust bearing shown in FIG.

FIG. 3 is a cross-sectional view showing a state in which the synthetic resin thrust bearing shown in FIG. 1 is incorporated in a strut assembly.

FIG. 4 is a cross-sectional view of another specific example of the synthetic resin thrust bearing of the present invention.

FIG. 5 is a sectional view of still another specific example of the synthetic resin thrust bearing of the present invention.

FIG. 6 is a cross-sectional view of another specific example of the synthetic resin thrust bearing of the present invention.

FIG. 7 is a sectional view of another specific example of the synthetic resin thrust bearing of the present invention.

FIG. 8 is a sectional view of another specific example of the synthetic resin thrust bearing of the present invention.

FIG. 9 is a sectional view of still another specific example of the synthetic resin thrust bearing of the present invention.

FIG. 10 is a sectional view of a conventional synthetic resin thrust bearing.

11 is a cross-sectional view showing a state in which the synthetic resin thrust bearing shown in FIG. 10 is incorporated in a strut assembly.

[Explanation of symbols]

 A Synthetic resin thrust bearing B Synthetic resin lower bearing case C Synthetic resin upper bearing case D Synthetic resin bearing piece 33 Base portion 40 Cylindrical protrusion 46 Cylindrical engaging protrusion 42 Annular recess 47 Bottom 53 Base 57 57 Cylindrical hanging 61 Cylindrical engagement Lower part 63 Annular recess 64 Bottom

Claims (5)

[Claims] 1. An upper bearing base portion, a cylindrical hanging portion that hangs from a lower surface of an annular inner peripheral side of the upper bearing base portion, and an upper annular recessed portion on the lower surface side of the upper bearing base portion in cooperation with the cylindrical hanging portion. As described above, a synthetic resin upper bearing case having a cylindrical engaging hanging portion that hangs from the lower surface of the outer peripheral side of the upper bearing base portion to the inner peripheral surface with an engaging surface, a lower bearing base portion, and the lower bearing base portion. An annular shoulder portion is formed on the upper surface of the lower bearing base portion between the cylindrical inner peripheral surface of the lower bearing base portion and the outer peripheral surface of the cylindrical protruding portion. A lower bearing case made of synthetic resin, comprising a cylindrical engaging protrusion protruding from the annular outer peripheral surface of the lower bearing base portion with an engaging surface on the outer peripheral surface so as to define an annular recess on the upper surface side of the lower bearing base portion. , Synthetic resin bearing pieces arranged in upper and lower annular recesses And the upper bearing case is
The engaging surface of the cylindrical engaging hanging portion is elastically fitted to the engaging surface of the cylindrical engaging protruding portion of the lower bearing case, the cylindrical hanging portion is engaged with the annular shoulder portion of the lower bearing case, and the end of the cylindrical hanging portion is engaged. Part is radially overlapped with the end of the cylindrical protrusion, and a sealing part by a labyrinth action is formed in the elastic fitting part and the overlap part to be combined with the lower bearing case. And a bottom surface of the bearing piece slidably in contact with the bottom surface of the bearing piece are each formed into a truncated cone surface. 2. In the upper annular recess, on the lower surface of the upper bearing base portion, on the one hand, an annular groove is formed in cooperation with the cylindrical engaging hanging part, and on the other hand, an upper inner annular recess is formed in cooperation with the cylindrical hanging part. An outer annular hanging portion is further formed, and in the lower annular concave portion, an annular groove is formed on the upper surface of the lower bearing base portion on the one hand in cooperation with the cylindrical engaging protrusion, and on the other hand, the cylindrical protruding portion. An outer annular protrusion which further defines and projects a lower inner annular recess in cooperation with the upper bearing case, wherein the upper bearing case has an end of the outer annular hanging part of the outer annular protrusion of the lower bearing case. 2. The synthetic resin thrust bearing according to claim 1, wherein the synthetic resin thrust bearing is formed so as to be overlapped with the end portion in the radial direction, a sealing portion formed by a labyrinth action is formed in the overlapped portion, and is combined with the lower bearing case. 3. An outer annular hanging part, which cooperates with a cylindrical engaging hanging part to define an upper outer annular groove and hangs on the lower surface of the upper bearing base portion in the upper annular recess, and on the other hand, the cylindrical hanging part. Cooperatively forming an upper inner annular groove and, on the other hand, an inner annular hanging portion that cooperates with the outer annular hanging portion to define and hang down an upper intermediate annular recessed portion, respectively. On the upper surface of the bearing base portion, an outer annular protrusion that cooperates with the cylindrical engaging protrusion to define and protrudes a lower outer annular groove, on the one hand, a lower inner annular groove in cooperation with the cylindrical protrusion, and on the other hand, , An inner annular protrusion that cooperates with the outer annular protrusion to define and protrude lower intermediate annular recesses, respectively, and the upper bearing case includes an end of the inner annular hanging portion and an outer annular hanging portion. End of the inner annular protrusion The synthetic resin thrust bearing according to claim 1, wherein the synthetic resin thrust bearing is formed so as to be radially overlapped with an end portion of the outer annular projection and a sealing portion by a labyrinth action is formed in the overlapping portion and is combined with the lower bearing case. 4. The bottom surfaces of the upper and lower annular recesses and both end surfaces of the bearing piece slidably contacting the bottom surfaces are each formed into a frustoconical surface having an upward slope from the inner diameter side to the outer diameter side. Item 5. The synthetic resin thrust bearing according to any one of items 1 to 3. 5. The bottom surfaces of the upper and lower annular recesses and both end surfaces of the bearing piece slidably contacting the bottom surfaces are each formed into a frustoconical surface having an upward slope from the inner diameter side to the outer diameter side. Item 5. The synthetic resin thrust bearing according to any one of items 1 to 3.