JP2003130118A - Friction ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permanently suppress oscillation of micro amplitude, when a piston speed is within a very low-speed range. SOLUTION: A friction ring 7 slides on a piston rod 2, while being held by a rod guide 3, otherwise it slides on a cylinder 1 and being held by a piston 9. The friction ring 7 is formed to be annular with a single slit 7a, and comprises partial slits 7b, connected at an end, at a plurality of points in the circumferential direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a friction ring used when forming a bearing portion and a piston portion in a hydraulic shock absorber.

[0002]

2. Description of the Related Art For example, a bearing portion of a hydraulic shock absorber shown in FIG. 6 is arranged at an opening end 1a of a cylinder 1 and seals the opening end 1a of the cylinder 1 while penetrating a piston rod 2 into a shaft core portion. The rod guide 3 is provided with a rod guide 3 and a bush 4 held on the inner circumference of the rod guide 3 and in sliding contact with the outer circumference of the piston rod 2. Further, the bush 4 is positioned above the bush 4 and the inner circumference thereof is a piston. The rod 5 has a seal 5 which is in sliding contact with the outer periphery of the rod 2.

Incidentally, the outer peripheral portion of the rod guide 3 is
A so-called reservoir is formed between the cylinder 1 and the outer cylinder 6 in which the notch groove 3a is formed and the outer cylinder 6 is adjacently provided, and the lubricant oil that may collect in the upper end of the rod guide 3 is formed between the cylinder 1 and the outer cylinder 6. It is going to return to R.

Further, the bush 4 is made of, for example, copper so as to have excellent slidability with respect to the piston rod 2.

Therefore, in this bearing portion, although the bush 4 is distributed by the rod guide 3,
The concentricity and slidability of the piston rod 2 with respect to the cylinder 1 are guaranteed.

The seal 5 prevents external dust from entering the inside, and prevents the lubricating oil from leaking from the sliding gap S between the bush 4 and the piston rod 2 to the outside. It will be.

At this time, the seal 5 has a predetermined tightening margin,
That is, the sliding contact is made with the piston rod 2 while having a friction that is a predetermined dynamic frictional force. Therefore, as long as the friction here is properly controlled, the piston rod 2 appears and disappears in the cylinder 1, that is, the hydraulic shock absorber. The expansion and contraction operation in the above will be smoothly realized.

[0008]

However, in the above bearing portion, the piston speed is 0.01 m / s.
It may be pointed out that a slight vibration of 1 to 2 mm or less with respect to the cylinder 1 in the piston rod 2 in the very low speed region of ec or less cannot be properly suppressed with time.

That is, at the time of assembling the hydraulic shock absorber, the tightening allowance is set in the seal 5 so as to generate an appropriate friction against the above vibration, but since the hydraulic shock absorber is used, the seal 5 may be worn, and in this case, the set friction may not be generated from the beginning.

As a result, when a running vehicle mounted on the hydraulic shock absorber slowly crosses a large swell on the road surface, the hydraulic shock absorber expands and contracts forever after that even though the small swell is not crossed. Will continue to occur.

The present invention was devised in view of the above-mentioned circumstances, and an object thereof is to utilize a hydraulic shock absorber to cause a slight vibration when the piston speed is in a very low speed region. It is to provide a friction ring which can be suppressed permanently and is optimal for expecting improvement in versatility in the hydraulic shock absorber.

[0012]

In order to achieve the above-mentioned object, the structure of the present invention is applied to a friction ring which is slidably contacted with a piston rod while being held by a rod guide or slidably contacted with a cylinder while being held by a piston. Then, in the first configuration, while being formed in an annular shape having a slit in a direction along the axial core line at one location in the circumferential direction, there are partial slits connected at the ends in the direction along the axial core line at a plurality of locations in the circumferential direction. I will do it.

Further, in the second structure, slits are formed at a plurality of locations which are annularly formed at equal intervals in the circumferential direction, and have slits in the direction along the axial core line. It is assumed that the annular portions are connected in series.

Incidentally, in each of the above-mentioned configurations, the friction ring may be formed in a tubular shape instead of being formed in an annular shape.

In the second construction, the wall thickness of the annular portion is preferably set thinner than the wall thickness of the main body portion.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the illustrated embodiments. First, as shown in FIG. 1, the friction ring according to the present invention is used for a bearing portion in a hydraulic shock absorber. The case is shown.

Therefore, even though it is illustrated below, it basically has the same structure as the above-mentioned conventional bearing portion, and therefore the structure becomes the same as the conventional case. The same reference numerals are allotted in the drawings, and detailed description thereof will be omitted unless necessary.

That is, in the present invention, as shown in FIG. 1, the friction ring 7 is accommodated in the annular groove 3b formed on the inner peripheral side of the rod guide 3 while being held by the rod guide 3. While piston rod 2
It is supposed to slide.

At this time, the friction ring 7 is
The inner circumference of the piston rod 2 is slidably contacted with the outer circumference of the piston rod 2, and the tightening ring 8 made of an elastic material is also housed in the annular groove 3b and is interposed between the outer circumference of the friction ring 7 and the piston rod 2. It is said that the tightening margin for will be set.

The friction ring 7 is shown in FIG.
As shown in FIG. 3, a slit 7a is formed in one direction in the circumferential direction and has a slit 7a in the direction along the shaft core line, while a plurality of circumferential slits have partial slits 7b connected at the ends in the direction along the shaft core line. There is.

Incidentally, in FIG. 2, the slit 7a shown in FIG. 2A is formed by opposing both ends 7c shown in FIG.

By the way, in the present invention, the friction ring 7 is formed so as to generate friction with the piston rod 2 by the elastic force of the tightening ring 8. For example, PTFE (tetrafluoroethylene resin) is used. ),
Alternatively, a thermoplastic polyimide resin, and further NBR
It is said to be composed of a composite material of (rubber) and a thermoplastic polyimide resin.

When the friction ring 7 is made of a thermoplastic polyimide resin, it can be formed by injection molding such as fluid immersion, and compared with the case where it is made of PTFE, the lubricity of the piston rod 2 is improved. Is advantageous when priority is given to.

On the other hand, the tightening ring 8 is an O-ring or a square ring made of an elastic material such as rubber.
When the friction ring 7 is housed together with the friction ring 7 in the annular groove 3b described above, the friction ring 7 is provided adjacent to the outer circumference which is the back surface of the friction ring 7.
Is said to be pressed against the piston rod 2 side.

Incidentally, in the place shown in FIG. 3, the friction ring 7 has a ring-interposed groove 7d on the outer periphery which is the back surface thereof.
In this case, the tightening ring 8 is housed in the ring insertion groove 7d. In this case, it is easy to ensure the integrity of the friction ring 7 and the tightening ring 8 during the assembling work. Become.

Therefore, in the present invention, by appropriately setting the biasing force of the tightening ring 8 to the friction ring 7, the tightening allowance, that is, the tightening allowance of the friction ring 7 to the piston rod 2 is appropriate. Will be set to.

Although not shown, when the friction ring is formed in an annular shape by aligning a plurality of divided bodies in the circumferential direction, the urging force of the tightening ring acts on the friction ring in a well-balanced manner.

When the friction ring is formed in an annular shape by aligning a plurality of divided bodies in the circumferential direction, the tightening margin is set as compared with the case where the friction ring is simply formed in an annular shape. It is advantageous in that the precise ring size control is not required and the tightening margin can be set by the tightening ring.

From this fact, according to the present invention, the friction ring 7 is a single component, which is advantageous in reducing the number of components, but the urging force of the fastening ring 8 is balanced. Good friction ring 7
It can be pointed out that it becomes difficult to act on.

However, in the present invention, the friction ring 7 not only has the slit 7a at one location, but also has the partial slits 7b connected to the circumferential direction at a plurality of locations at the ends in the axial direction.

Therefore, from this fact, the friction ring 7 is a single component in appearance, but functionally functions almost the same as when a plurality of divided bodies are aligned in the circumferential direction. Will be done.

As a result, even in the friction ring 7 according to the present invention, it is possible to apply the biasing force of the tightening ring 8 in a well-balanced manner.

In view of the above, according to the present invention, the friction ring 7 is brought into sliding contact with the outer circumference of the piston rod 2 under the urging force from the tightening ring 8, and therefore the friction ring 7 produces the friction as set. It will be in a state of exerting.

Therefore, in the case where the hydraulic shock absorber is used for a long period of time and the seal 5 is worn so that proper friction cannot be set in the seal 5 from the beginning, the friction ring 7 can be used. Thus, the friction on the piston rod 2 is guaranteed.

As a result, for example, if the piston speed is 0.
It is possible to properly suppress a slight vibration of 1 to 2 mm or less with respect to the cylinder 1 in the piston rod 2 in the very low speed region of 01 m / sec or less.

This means that, when a running vehicle equipped with a hydraulic shock absorber embodying this bearing portion slowly travels over a large swell on the road surface and then travels on a flat road, the hydraulic shock absorber is indefinite. Will not cause the problem of continuous expansion and contraction.

From the above, the friction ring 7
Of course, the rubber or the thermoplastic polyimide resin described above, or a composite material of the rubber and the thermoplastic polyimide resin, further, it may be made of any material other than tetrafluoroethylene resin, the point is The material may be selected in consideration of the size and application of the hydraulic shock absorber in which the bearing portion is embodied, and the usage situation.

FIG. 4 shows an embodiment in which the friction ring 7 according to the present invention is embodied in the piston portion of the hydraulic shock absorber. In this embodiment, the friction ring 7 is adjacent to the inner circumference which is the back surface. It is supposed that the friction for the cylinder 1 is set by the backup ring 9 provided.

At this time, it is assumed that the friction ring 7 and the backup ring 9 are housed in the annular groove 10a formed in the piston 10, and the annular groove 10b formed separately in the piston 10 has a piston. The ring 11 is said to be housed.

By the way, in the piston ring 11, the rod side chamber R1 and the piston side chamber R1 in the cylinder 1 by the piston 10 are brought into sliding contact with the cylinder 1.
The definition of 2 has been realized.

By the way, the friction ring 7 is made of the same material as the friction ring 7 shown in FIG. 1, so a further description thereof will be omitted, but as shown in FIG. 5, it is formed in an annular shape. A main body portion 7f having slits 7e in a direction along the shaft core line at a plurality of locations at equal intervals in the circumferential direction, and an annular portion 7g having no slits continuously provided at one end of the main body portion 7f in the direction along the shaft core line. It is supposed to have.

As a result, the friction ring 7 arranged in the piston portion is, as a whole, compared with the friction ring 7 arranged in the bearing portion, the slit 7a corresponding to the abutment (see FIG. 2). ), But the main body portion 7f has a slit 7e corresponding to the abutment.

Therefore, from this fact, the friction ring 7 can be brought into sliding contact with the cylinder 1 in good balance by the urging force from the backup ring 9 described later.

Incidentally, the annular portion 7g is set to be thinner than the main body portion 7f so as not to prevent the main body portion 7f from slidingly contacting the cylinder 1 in a well-balanced manner. When the inner diameter is the same as the inner diameter of the portion 7f, the outer diameter is designed to be smaller than the outer diameter of the main body portion 7f.

On the other hand, the backup ring 9 is composed of an O-ring or a square ring formed of an elastic body such as rubber, like the tightening ring 8 described above.

Therefore, even in the case of the backup ring 9, the tightening margin, that is, the tightening margin of the friction ring 7 with respect to the cylinder 1 is properly set by appropriately setting the biasing force with respect to the friction ring 7. It will be.

Although not shown, even in this backup ring 9, as in the case shown in FIG.
The friction ring 7 may be housed in a ring insertion groove formed on the inner periphery of the back surface of the friction ring 7.

The above-mentioned point is the friction ring 7
However, from the intent of the present invention, instead of being formed in a ring, it may be formed in a tubular shape, the operation effect in this case Of course this is not different.

[0049]

As described above, claim 1 and claim 2 are as follows.
In the invention, since the friction ring is formed as a single component as compared with the case where the friction ring is formed in an annular shape by aligning a plurality of divided bodies in the circumferential direction, the workability of assembling in the hydraulic shock absorber is improved. There is an advantage that

Not only is the friction ring slidably contacting the piston rod or cylinder while having a predetermined friction, there is no friction ring,
Compared to the case where the bush only makes sliding contact with the piston rod and the case where the piston ring only makes sliding contact with the cylinder, a predetermined friction can be permanently ensured.

Therefore, even if the hydraulic shock absorber is used for a long period of time and the seal is worn so that proper friction due to the seal cannot be set from the beginning, the friction ring causes the piston to move. Friction on the rod or on the cylinder is guaranteed.

As a result, for example, when the piston speed is 0.
It is possible to properly suppress the minute vibration of 1 to 2 mm or less with respect to the cylinder in the piston rod in the very low speed region of 01 m / sec or less. For example, a hydraulic shock absorber embodying this bearing portion. When the traveling vehicle mounted on the vehicle travels on a flat road after slowly passing over a large swell on the road surface, the hydraulic shock absorber will not continue to expand and contract forever.

As a result, according to the present invention, it is optimal for expecting an improvement in versatility in the hydraulic shock absorber embodying the present invention.

[Brief description of drawings]

FIG. 1 is a partial vertical cross-sectional view showing a state in which a friction ring according to the present invention is used as a shaft sealing portion in a hydraulic shock absorber.

FIG. 2 shows a friction ring, in which (A) is
In the upper end view, (B) is a partially broken development view.

FIG. 3 is a partial vertical cross-sectional view showing another connection state of the tightening ring with the friction ring.

FIG. 4 is a partial vertical cross-sectional view showing a state in which a friction ring is used for a piston portion of a hydraulic shock absorber.

5A and 5B show a friction ring according to another embodiment, where FIG. 5A is a top view of a half section and FIG. 5B is a partially broken development view.

FIG. 6 is a view showing a conventional bearing portion of the hydraulic shock absorber, as in FIG. 1.

[Explanation of symbols]

1 cylinder 1a Open end 2 piston rod 3 Rod guide 3a Notch groove 3b, 10a, 10b annular groove 4 bush 5 seals 6 outer cylinder 7 friction ring 7a, 7e slit 7b Partial slit 7c Both ends forming a slit 7d ring insertion groove 7f body 7g annular part 8 Tightening ring 9 backup ring 10 pistons 11 piston ring R reservoir R1 Rod side chamber R2 piston side chamber

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Etsuro Nakata             2-4-1, Hamamatsucho, Minato-ku, Tokyo World Trade             Yasu Center Building Kayaba Industry Co., Ltd. F-term (reference) 3J069 AA50 CC18

Claims (2)

[Claims] 1. A friction ring, which is held by a rod guide and is slidably contacted with a piston rod, or is slidably contacted with a cylinder while held by a piston, and which has a slit at one circumferential position along a shaft core line. The friction ring, which is formed in a plurality of positions and has partial slits connected to each other at the ends in the direction along the axis line while being formed in the circumferential direction. 2. A friction ring, which is held by a rod guide and is in sliding contact with a piston rod, or is held by a piston and is in sliding contact with a cylinder. A friction ring characterized in that an annular portion having no slit is continuously provided at one end of a main body portion having a slit along a core line in a direction along an axial core line.