JP3832032B2 - Synthetic plastic thrust bearing - Google Patents

Description

[0001]
BACKGROUND 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 suspension (McFarso type) in a four-wheeled vehicle.
[0002]
[Problems to be solved by the invention]
Generally, a strut type suspension used for a front wheel of a four-wheeled vehicle has a structure in which a coil spring is combined with a strut assembly in which a hydraulic shock absorber is incorporated in an outer cylinder integrated with a main shaft.
[0003]
There are two types of suspensions: the type in which the piston rod of the assembly rotates when the strut assembly rotates with the coil spring by the steering operation, and the type in which the piston rod does not rotate. A bearing is used between the mounting member of the vehicle body and the upper spring seat of the coil spring so as to allow it smoothly.
[0004]
Conventionally, a roller bearing or a synthetic resin sliding bearing using a ball has been used for the bearing at this location, and the present applicant uses the synthetic resin sliding bearing as a synthetic resin according to Japanese Utility Model Publication No. 3-39614. Proposed as a thrust bearing.
[0005]
The synthetic resin thrust bearing according to this proposal has a steering force caused by a dust seal made of a rubber elastic body that is mounted between the sliding surfaces so as to prevent intrusion of dust or the like into the sliding surfaces. Can be eliminated, and dust and the like can be prevented from entering the sliding surface as much as possible, and a stable and smooth steering force can be obtained.
[0006]
By the way, since the strut type suspension is attached to a portion where dust, muddy water, etc. directly act while the vehicle is running, the usage environment of the thrust bearing incorporated in the strut type suspension is extremely harsh. The synthetic resin thrust bearing proposed in Japanese Patent Publication No. Gazette is formed by simply elastically mounting a case (upper case) to a bearing body (lower case) on the outer peripheral side thereof. There still remains a risk of intrusion of dust, muddy water, etc., into the sliding surface from the part.
[0007]
Moreover, in the synthetic resin thrust bearing according to the proposal, sliding friction is generated between the case and the bearing body at the elastic mounting portion during steering, and there is a possibility of generating unpleasant noise due to this sliding friction.
[0008]
The present invention has been made in view of the above points, and can prevent dust and the like from entering the sliding surface from the outer peripheral surface side, thereby reducing the sliding characteristics of the bearing caused by the penetration of dust and the like. An object of the present invention is to provide a synthetic resin thrust bearing that can maintain a smooth steering force during a steering operation for a long period of time without generating any unpleasant noise.
[0009]
[Means for Solving the Problems]
The synthetic resin thrust bearing of the present invention is made of a synthetic resin lower case, a synthetic resin upper case rotatably combined with the lower case, and a synthetic resin arranged in an annular space between the upper and lower cases. Each of the outer circumferential side and the inner circumferential side of the annular space is sealed to the outside by labyrinths on the outer circumferential side and the inner circumferential side formed between the upper and lower cases. In the labyrinth on the outer peripheral side, an annular body that closes the labyrinth by its own weight is disposed so as to be slidably supported by the upper and lower cases.
[0010]
In the above-described synthetic resin thrust bearing of the present invention, the lower case is arranged via a circular stepped portion radially outward with respect to the insertion hole and a disk-like lower case base portion having an insertion hole in the center portion. A first inner annular protrusion projecting from the upper surface of the lower case base, a locking portion formed radially inward with respect to the outer peripheral surface of the lower case base, and the locking portion A disc-shaped upper case having a first outer annular protrusion disposed radially inward and projecting from the upper surface of the lower case base, and having an insertion hole in the center. A base part, an annular hanging part that hangs down from the lower surface of the upper case base part and whose tip faces the annular step part of the lower case, and cooperates with the annular hanging part radially outwardly with respect to the annular hanging part So as to form a narrow inner annular recess. An inner annular lip portion, and an outer annular portion that hangs down from the lower surface of the upper case base portion so as to form a wide intermediate annular recess in cooperation with the inner annular lip portion radially outward with respect to the inner annular lip portion. A lip portion and an outer annular suspending portion that hangs down from the lower surface of the upper case base portion so as to form an outer annular recess in cooperation with the outer annular lip portion radially outward with respect to the outer annular lip portion; A locking portion formed on the radially inner surface of the outer annular drooping portion, and the first inner annular protruding portion has a narrow inner side of the upper case so as to form a labyrinth on the inner peripheral side. The first outer annular protrusion is disposed in the annular recess, and is disposed in the outer annular recess of the upper case so as to form an outer peripheral labyrinth. An annular space is arranged It has been made.
[0011]
Further, in the synthetic resin thrust bearing of the present invention, the lower case has a narrow inner annular recess in cooperation with the first inner annular projecting portion radially outward with respect to the first inner annular projecting portion. As further formed, it further comprises a second inner annular protrusion protruding from the upper surface of the lower case base portion, and the inner annular lip portion of the upper case forms an inner labyrinth, Arranged in the inner annular recess of the lower case.
[0012]
Further, the lower case base is formed radially inward with respect to the first outer annular protrusion so as to form a narrow outer annular recess in cooperation with the first outer annular protrusion. A second outer annular protrusion projecting from the upper surface of the upper portion, and the outer annular lip portion of the upper case is disposed in the outer annular recess of the lower case so as to form an outer labyrinth. Has been. In this case, the second outer annular protrusion protrudes from the upper surface of the lower case base portion so as to form an intermediate annular recess in the lower case in cooperation with the second inner annular protrusion. An annular space in which the bearing body is disposed is formed by the intermediate annular recess of the case.
[0013]
In the present invention, the bearing body is slidably in contact with at least one of the lower and upper surfaces of the upper and lower case base portions, and in a preferred example, both the lower and upper surfaces of the upper and lower case base portions. In a case where only one of the lower surface and the upper surface of the case base portion is slidably contacted, the bearing body may be integrally fixed to the upper or lower case base portion on the other side.
[0014]
The annular body in the present invention is made of a synthetic resin or metal plate-shaped ring, circular cross-section or elliptical ring.
[0015]
The synthetic resin constituting the upper and lower cases in the synthetic resin last bearing of the present invention is preferably excellent in sliding properties and mechanical properties such as wear resistance, impact resistance, creep resistance, etc. The synthetic resin constituting the bearing body disposed between the lower cases is particularly preferably self-lubricating, for example, polyacetal resin, polyamide resin, polyester resin such as polybutylene terephthalate (PBT), polyolefin such as polyethylene and polypropylene Resins and the like are used favorably, and polycarbonate resins and the like can also be used.
[0016]
The upper and lower cases can be made of the same synthetic resin as the synthetic resin that constitutes the bearing body, but it has a particularly good combination of the synthetic resin used in the bearing body and the friction characteristics and is relatively rigid. It is desirable that the synthetic resin is high. Examples of desirable combinations are shown in the following table.
[0017]
【table】
Bearing piece Upper and lower cases Friction coefficient Wear amount (mm)
Polyacetal Polyamide 0.05 0.020
Polyamide polyacetal 0.04 0.021
Polyethylene polyacetal 0.04 0.038
Polyacetal PBT 0.07 0.045
Polyacetal Polyacetal 0.06 0.025
Polyacetal steel (steel) 0.11 0.095
[0018]
In the table, the friction characteristics are the results obtained under the following test conditions.
[0019]
[Test conditions]
Thrust load 350kg / cm ² Swing angle ± 35 degrees Swing speed 60cpm
Lubrication method Apply grease to sliding surface during start-up. [0020]
The amount of wear indicates the amount of dimensional change (mm) of the bearing piece after the above test was performed 1,000,000 times.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention and the embodiments of the present invention will be described in more detail based on preferred embodiments shown in the drawings. The present invention is not limited to these examples.
[0022]
【Example】
1 and 2, a synthetic resin thrust bearing 1 of this example includes a lower case 2 made of synthetic resin, an upper case 3 made of synthetic resin rotatably combined with the lower case 2, and upper and lower cases 2. In order to close the annular bearing body 5 made of synthetic resin and the labyrinth 6 on the outer peripheral side, which will be described later, by its own weight, slide relative to the upper and lower cases 2 and 3. And an annular body 7 that is freely supported and arranged.
[0023]
The lower case 2 is arranged via a circular lower step portion 13 radially outward with respect to the insertion hole 11 through a disc-shaped lower case base portion 12 having an insertion hole 11 at the center, and the lower case base portion 12. An inner annular protrusion 15 projecting from the upper surface 14 of the lower case base 12 and a latching portion formed radially inward with respect to the outer peripheral surface 16 of the lower case base 12 and comprising an annular step portion having a flat surface 17, an outer annular protrusion 18 disposed radially inward with respect to the locking portion 17 and projecting from the upper surface 14 of the lower case base 12, and a radially outward direction with respect to the inner annular protrusion 15. The inner annular protrusion 20 projecting from the upper surface 14 of the lower case base 12 and the outer annular protrusion 18 so as to form a narrow inner annular recess 19 in cooperation with the inner annular protrusion 15. Inwardly in the radial direction, in cooperation with the outer annular protrusion 18, the narrow outer side The lower case base portion 12 is formed so as to form a wide intermediate annular recess 22 in cooperation with the inner annular protrusion 20 and radially outwardly with respect to the inner annular protrusion 20. The lower annular surface 23 of the lower case base 12 is communicated with the insertion hole 11 and the insertion hole 24 concentric with the insertion hole 11 is defined by the inner peripheral surface. And a cylindrical portion 26 projecting from the head.
[0024]
The upper case 3 hangs down from a disk-like upper case base portion 32 having an insertion hole 31 concentric with the same diameter at the center and the lower surface 33 of the upper case base portion 32, and the tip 34 is a lower case. An annular hanging portion 35 facing the two annular step portions 13, and an upper portion so as to form a narrow inner annular recessed portion 36 in cooperation with the annular hanging portion 35 radially outward with respect to the annular hanging portion 35. An inner annular lip portion 37 depending from the lower surface 33 of the case base portion 32 and a wide intermediate annular recess 38 in cooperation with the inner annular lip portion 37 radially outward from the inner annular lip portion 37. Further, an outer annular lip portion 39 hanging from the lower surface 33 of the upper case base portion 32 and an outer annular recess 40 are formed in cooperation with the outer annular lip portion 39 radially outward with respect to the outer annular lip portion 39. So that the top The outer annular hanging portion 41 suspended from the lower surface 33 of the support base portion 32 and the engaging portion 42 formed of an inwardly inclined annular inclined surface formed on the radially inner surface of the outer annular hanging portion 41 are provided. . An inner peripheral surface of the annular hanging portion 35 communicates with the insertion hole 31 and defines an insertion hole 43 having the same diameter and concentricity as the insertion hole 31.
[0025]
In the synthetic resin thrust bearing 1, the outer annular protrusion 18 of the lower case 2 is arranged in the outer annular recess 40 of the upper case 2 so as to form the labyrinth 6 on the outer peripheral side, and the annular protrusion 23 of the lower case 2. Is arranged on the outer peripheral side of the intermediate annular recess 38 of the upper case, and the outer annular lip 39 of the upper case 3 is arranged in the outer annular recess 21 of the lower case 2.
[0026]
Thus, the labyrinth 6 on the outer circumferential side communicates with the annular space 4 formed by the intermediate annular recesses 22 and 38 on the inner circumferential side, and the inner circumferential surface of the outer annular hanging portion 41 and the lower case base on the outer circumferential side. It extends to the annular opening 51 between the outer peripheral surface of the part 12 and seals the annular space 4 to the outside by a labyrinth action.
[0027]
On the other hand, in the synthetic resin thrust bearing 1, the inner annular protrusion 15 of the lower case 2 is arranged in the inner annular recess 36 of the upper case 3 so as to form an inner peripheral labyrinth 55. The inner annular protrusion 20 is disposed on the inner peripheral side of the intermediate annular recess 38 of the upper case 3, and the inner annular lip portion 37 of the upper case 3 is disposed in the inner annular recess 19 of the lower case 2. .
[0028]
In this way, the labyrinth 55 on the inner circumferential side opens into the annular space 4 on the outer circumferential side, and on the inner circumferential side, an annular shape between the tip 34 of the annular hanging portion 35 and the flat surface of the annular step portion 13 is formed. It extends to the opening 56 and seals the annular space 4 to the outside by a labyrinth action.
[0029]
In this example, the bearing body 5 is formed separately from the upper and lower cases 3 and 2, and the upper surface 61 and the lower surface 33 and the upper surface 14 of the upper and lower base portions 32 and 12 are slidably in contact with each other. The upper surface 61 has a plurality of radially extending grooves 63 and an annular groove 64 communicating with the grooves 63 as a lubricating grease reservoir. The lower surface 62 is also lubricated in the same manner. As a grease reservoir, a plurality of radially extending grooves 65 and an annular groove 66 communicating with the grooves 65 are formed.
[0030]
In this example, the annular body 7 is made of a metal plate-like ring, and the outer peripheral side thereof is seated on a locking portion 42 formed of an annular inclined surface, and is supported by the upper case 3 so as to be relatively slidable. The inner peripheral side is seated on the flat surface of the locking portion 17 formed of an annular step portion, and is supported by the lower case 2 so as to be relatively slidable.
[0031]
The annular space 4 and the labyrinths 6 and 55 are filled with lubricating grease as necessary.
[0032]
The synthetic resin thrust bearing 1 is used by being mounted via a seat 74 between a spring receiver 72 of a strut assembly 71 and a vehicle body side mounting member 73 as shown in FIG. 3, for example. In this case, the piston rod 75 of the strut assembly 71 has an outer case whose outer peripheral surface defines the lower case base 12 and the cylindrical portion 26 that define the insertion holes 11 and 24, and an upper case that defines the insertion holes 31 and 43. They are arranged in the insertion holes 11 and 24 and the insertion holes 31 and 43 so as to have bearing clearances (clearances) with respect to the inner peripheral surfaces of the base portion 32 and the annular hanging portion 35. 3, 76 is a coil spring, 77 is a bump stopper (rubber) disposed on the lower surface of the spring receiver 72 so as to surround the outer peripheral surface of the piston rod 75, and 78 is a strut.
[0033]
In the synthetic resin thrust bearing 1 used for the strut assembly 71, the bearing body 5 supports the thrust load of the vehicle body and allows the spring receiver 72 to smoothly rotate relative to the vehicle body side mounting member 73.
[0034]
In the synthetic resin thrust bearing 1, the annular body 7 is supported by the upper and lower cases 3 and 2 so as to be relatively slidable so that the labyrinth 6 on the outer peripheral side is closed by its own weight on the annular opening 51 side. Since the annular body 7 is arranged on the opening 51 side, dust or the like can be prevented from entering the labyrinth 6, and thus dust or the like can be prevented from entering the sliding surface of the bearing body 5. In addition, since the annular body 7 is simply placed and supported on the upper and lower cases 3 and 2, there is almost no unpleasant noise during sliding.
[0035]
In the above, an example in which the lower casing base 12 is provided with the inner annular protrusion 20, the outer annular protrusion 23, and the cylindrical part 26 is shown, but the synthetic resin thrust bearing 1 is configured by omitting at least one of these. As an example, a synthetic resin thrust bearing 1 that does not include the inner annular protrusion 20, the outer annular protrusion 23, and the cylindrical portion 26 is shown in FIG. Further, in the synthetic resin thrust bearing 1 shown in FIG. 4, a plurality of protrusions 81 protrude from the lower surface 25 of the lower case base 12, and the protrusions 81 are formed in the through holes 82 formed in the spring receiver 72. The lower case 2 cannot be rotated relative to the spring receiver 72 by being fitted.
[0036]
Furthermore, as shown in FIG. 4, the annular body 7 may be formed of a circular ring in cross section. It may be configured from a surface.
[0037]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent dust and the like from entering the sliding surface from the outer peripheral surface side, and at the time of steering operation without deteriorating the sliding characteristics of the bearing due to the penetration of dust and the like. It is possible to provide a synthetic resin thrust bearing that can maintain a smooth steering force over a long period of time and can prevent generation of unpleasant noise.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a preferred embodiment of the present invention.
FIG. 2 is a plan view of the bearing body of the embodiment shown in FIG.
FIG. 3 is an explanatory diagram of an example in which the embodiment shown in FIG. 1 is used in a strut assembly.
FIG. 4 is a cross-sectional view of another preferred embodiment of the present invention.
[Explanation of symbols]
1 Synthetic plastic thrust bearing 2 Lower case 3 Upper case 4 Annular space 5 Bearing body 6 Labyrinth 7 Annular body

Claims (10)

A synthetic resin lower case, a synthetic resin upper case rotatably combined with the lower case, and a synthetic resin annular bearing body disposed in an annular space between the upper and lower cases. Each of the outer peripheral side and inner peripheral side of the annular space is sealed to the outside by an outer peripheral side and inner peripheral side labyrinth formed between the upper and lower cases. A synthetic resin thrust bearing in which an annular body that closes the labyrinth by its own weight is arranged so as to be slidable relative to the upper and lower cases. The lower case has a disk-like lower case base portion having an insertion hole in the center portion, and is arranged on the upper surface of the lower case base portion with an annular step portion radially outward from the insertion hole. A first inner annular protrusion, a locking portion formed radially inward with respect to the outer peripheral surface of the lower case base portion, and a lower case disposed radially inward with respect to the locking portion A first outer annular projecting portion projecting from the upper surface of the base portion, and the upper case includes a disk-like upper case base portion having an insertion hole in the center portion, and the upper case base portion. An annular hanging portion that hangs down from the lower surface and whose tip faces the annular step portion of the lower case, and forms a narrow inner annular concave portion in cooperation with the annular hanging portion radially outward with respect to the annular hanging portion. The inner annular lip portion hanging from the lower surface of the upper case base portion and the inner annular lip portion On the other hand, the outer annular lip portion hanging from the lower surface of the upper case base portion and the outer annular lip portion so as to form a wide intermediate annular concave portion in cooperation with the inner annular lip portion radially outward. It is formed on the outer annular drooping portion that hangs down from the lower surface of the upper case base portion and the radially inner surface of the outer annular drooping portion so as to form an outer annular recess in cooperation with the outer annular lip portion radially outward. And the first inner annular protrusion is disposed in the narrow inner annular recess of the upper case so as to form an inner peripheral labyrinth, and the first outer The synthetic resin thrust bearing according to claim 1, wherein the annular protrusion is disposed in an outer annular recess of the upper case so as to form an outer peripheral side labyrinth. The synthetic resin thrust bearing according to claim 2, wherein an annular space in which the bearing body is disposed is formed by the intermediate annular recess. The lower case has an upper surface of the lower case base portion so as to form a narrow inner annular recess in cooperation with the first inner annular projection radially outward with respect to the first inner annular projection. The inner annular lip of the upper case is disposed in the inner annular recess of the lower case so as to form an inner circumferential labyrinth. The synthetic resin thrust bearing according to claim 2 or 3. The lower case is radially inward with respect to the first outer annular protrusion so as to form a narrow outer annular recess in cooperation with the first outer annular protrusion. A second outer annular protrusion projecting from the upper surface is further provided, and the outer annular lip portion of the upper case is disposed in the outer annular recess of the lower case so as to form an outer labyrinth. The synthetic resin thrust bearing according to any one of claims 2 to 4. The second outer annular protrusion is dependent on the upper surface of the lower case base so as to form an intermediate annular recess in the lower case in cooperation with the second inner annular protrusion. The synthetic resin thrust bearing according to claim 5, as long as it does. The synthetic resin thrust bearing according to claim 6, wherein an annular space in which the bearing body is disposed is formed by an intermediate annular recess of the lower case. The synthetic resin thrust bearing according to any one of claims 1 to 7, wherein the bearing body is slidably in contact with at least one of a lower surface and an upper surface of the upper and lower case base portions. The synthetic resin thrust bearing according to any one of claims 1 to 8, wherein the annular body includes a plate ring made of synthetic resin or metal. The synthetic resin thrust bearing according to any one of claims 1 to 8, wherein the annular body is made of a synthetic resin or metal-made circular cross-section or elliptical ring.

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