JPH022514B2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a sliding mechanism consisting of, for example, a cylinder, a piston, a piston ring, etc., and is intended to improve the lubrication conditions between the piston and the piston ring. .

``Prior Art'' Taking as an example a sliding mechanism that includes the cylinder, piston, and piston ring, the piston ring is fitted into and held in an annular structure formed in the piston. However, it is impossible to eliminate a minute axial gap between the piston ring and the annular groove, and when the piston reciprocates with respect to the cylinder, the piston ring also reciprocates with respect to the piston within the annular groove.

``Problem to be Solved by the Invention'' Conventionally, for example, in a shock absorber having this type of sliding mechanism, the sliding part between the piston ring and the cylinder that constitute the shock absorber, and the sliding part between the piston rod and the guide bush that guides it, have been difficult to solve. Abrasion of sliding parts and the like has been considered a problem, and little consideration has been given to the abrasion between the piston ring and the piston. However, as anti-wear measures have been taken for each of the sliding parts, the wear between the piston ring and the piston can no longer be ignored.

Such a problem does not necessarily occur only between the piston ring and the piston, but also occurs between the floating bush and the annular groove of the support member that supports it.

"Means for Solving the Problems" In view of the above-mentioned circumstances, the present invention provides an annular sliding body such as a piston ring or a floating bush in which either the outer circumferential surface or the inner circumferential surface is a sliding surface, and the annular sliding body. comprising a sliding member that contacts and relatively slides on the sliding surface of the moving body, and a support member having an annular groove,
In the sliding mechanism in which the annular sliding body is fitted into the annular groove so as to be movable in the axial direction, a protruding portion whose central portion protrudes along the axial direction is formed on the sliding surface of the annular sliding body; , a recess is formed on the back side of the protrusion, and its axial cross-sectional shape is approximately arcuate, and the shape of the surface of the portion of the recess adjacent to the annular groove is adjusted to the relative shape of the annular sliding body and the annular groove. The shape is such that an oil film can be generated during movement.

"Function" As described above, if the annular sliding body is formed with a protrusion and a recess so that its axial cross-sectional shape is approximately arc-shaped, the annular sliding body has an arc-shaped portion that extends in the axial direction. Therefore, even if a large lateral load is applied to the annular sliding body, the load can be absorbed by the elastic deformation, so the annular sliding body, supporting member, or sliding member damage can be prevented.

Further, when the annular sliding body and the annular groove move relative to each other in the axial direction, an oil film is easily formed on the sliding surface due to the recess provided in the annular sliding body, and therefore, an oil film is easily formed on the sliding surface. , it is possible to effectively prevent the sliding surfaces of these two members from seizing or surface roughening.

"Example" The present invention will be described below with reference to the illustrated example.
In FIG. 1, 1 is a cylinder of a shock absorber used in a front suspension, 2 is a piston rod, and a piston 3 is integrally connected to this piston rod 2 by a nut 4. An annular groove 5 is formed on the outer peripheral surface of the piston 3, into which a piston ring 6 is fitted, and an outer peripheral sliding surface 7 of the piston ring 6 is in sliding contact with the inner surface 8 of the cylinder 1.

As shown in an enlarged and exaggerated manner in FIG. 2, a gap (δ) is formed in the axial direction between the annular groove 5 and the piston ring 6, and the piston 3
and piston ring 6 slide against each other within the range of the gap (δ). In the illustrated embodiment, the piston ring 6
is composed of two layers of bimetallic material, and the original sliding surface 7 side surface of the bimetallic material is an arcuate surface whose central part bulges outward along the axial direction.This allows the piston 3 to move into the cylinder 1. On the other hand, even when the sliding surface 7 is slightly inclined, the contact state between the sliding surface 7 and the inner surface 8 of the cylinder 1 is good.

The bottom surface 9 in the annular groove 5 is formed as a cylindrical surface parallel to the axial direction of the piston 3, and on the other hand, the inner circumferential surface of the piston ring 6 that contacts the bottom surface 9, that is, the surface on the back metal side of the bimetallic material has a circular shape. An annular recess 10 along the circumferential direction is formed and used as an oil reservoir. In the illustrated embodiment, the axial cross-sectional shape of the inner circumferential surface of the piston ring 6 is a shape in which two chevron-shaped arcuate surfaces bulging toward the bottom surface 9 of the annular groove 5 are smoothly continued; The middle portion of the recess 10 serves as the recess 10, and each top portion serves as a contact surface 11 with the bottom surface 9. By keeping the angle (θ) between the surface near both sides of each contact surface 11 in the axial direction and the bottom surface 9 small, when the piston ring 6 slides against the piston 3, the contact surface The shape is set so that an oil film can be easily formed on the surface.

In the above-mentioned configuration, since the recess 10 is formed on the inner circumferential surface of the piston ring 6, this portion can easily elastically deform itself in the radial direction compared to a flat piston ring, and the outer circumferential sliding surface 7 Coupled with the fact that 7 is an arcuate surface, the sliding surface 7 remains constant even when irregular loads are applied when the shock absorber operates.
and the inner surface 8 of the cylinder 1 is maintained in good condition. The recess 10 becomes an oil reservoir and oil is stored there, and when the piston 3 and the piston ring 6 slide relative to each other, the bottom surface of the annular groove 5 and the piston ring 6 come into contact due to the shape having the minute angle (θ). An oil film can be easily formed between the surface 11 and the surface 11, thereby preventing wear of that part.

FIG. 3 shows an embodiment in which the present invention is applied to a floating bushing.
An annular groove 18 is formed between the large diameter portion of the upper inner peripheral surface of the housing 16 and the presser member 17. 19 is a floating bush whose original sliding surface 20 side is the inner side,
While fitting the back metal side into the annular groove 18,
The sliding surface 20 is brought into sliding contact with the outer peripheral surface of a shaft 21 that reciprocates. This floating bush 19
The shape of the sliding surface 2 with respect to the piston ring 6 is
The only difference is that 0 is inside, and the sliding surface 2
The structure is similar to that of the piston ring 6, such as making 0 an arcuate surface with a central portion bulging inward and forming a recess 22 on the outer peripheral surface of the floating bush 19.

It is clear that the same effects as those of the above-mentioned embodiments can be obtained in this embodiment as well.

In the above embodiment, the depth of the recesses 10 and 22 is desirably set to about 100 μm or less, preferably about 50 μm.

"Effects of the Invention" As described above, according to the present invention, even when a large lateral load is applied to the annular sliding body, the load is absorbed by the elastic deformation of the annular sliding body, and the annular sliding body and the support To improve the wear resistance of the annular sliding body and the annular groove by preventing damage to the members or sliding members and making it easy to maintain an oil film between the annular sliding body and the annular groove. This has the effect of being able to.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is an enlarged view of the main part of FIG. 1, and FIG. 3 is a sectional view showing another embodiment of the present invention. 1...Cylinder, 3...Piston, 5, 18...
...Annular groove, 6...Piston ring, 7,20...
Sliding surface, 10, 22... recess, 11... contact surface,
15... Support member, 19... Floating bush, 21... Shaft.

Claims (1)

[Scope of Claims] 1. An annular sliding body with either an outer peripheral surface or an inner peripheral surface as a sliding surface, and a sliding member that contacts and relatively slides on the sliding surface of this annular sliding body, a support member having an annular groove, and the annular sliding body is fitted into the annular groove so as to be movable in the axial direction; A concave portion is formed on the back side of the concave portion so that its axial cross-sectional shape is approximately arcuate, and the shape of the surface of the portion adjacent to the annular groove of the concave portion is formed. , a sliding mechanism characterized by being formed in a shape capable of generating an oil film during relative movement between an annular sliding body and an annular groove.