JPH0522889U - Oil lock mechanism of hydraulic shock absorber - Google Patents

Abstract

(57) [Summary] [Objective] A smooth oil lock is applied in the compression stroke of a hydraulic shock absorber, and sliding of a member fitted with a bottomed tubular member is made smooth to improve durability and reliability. [Structure] At the end of the compression stroke of the piston rod 3, a free piston 21 slidably fitted in the bottomed tubular member 17 is pressed by a pressing member 35 and pushed down to lock the oil, and the free piston 21 A center pin 31 having a tapered tip portion 31a facing the through hole 32 is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an oil lock mechanism that prevents bottoming of a hydraulic shock absorber.

[0002]

[Prior Art]

 In the conventional hydraulic shock absorber, a cylinder is erected inside the outer tube, the piston rod is inserted into this cylinder, and the piston that is in sliding contact with the inner peripheral surface of the cylinder is fixed to the lower end of the piston rod. The valves are installed to open and close these oil passages.

As an oil lock mechanism in such a hydraulic shock absorber, a bottom valve mechanism is provided at the bottom of the outer tube (lower part of the cylinder), and a bottomed tubular member facing the inside of the cylinder on the bottom valve mechanism. The collar is provided with an orifice that connects the cylinder lower chamber and the reservoir chamber via the bottom valve mechanism.On the other hand, the extension of the lower end of the piston rod is fitted to the inner surface of the collar. A possible piece is installed, a check valve is arranged in this piece, and some pieces have oil holes.

In the oil lock mechanism of the hydraulic shock absorber described above, when the piece is fitted into the collar at the end of the compression stroke of the piston rod, the working oil is contained between the piece and the collar to lock the oil. Then, at the beginning of the extension stroke, hydraulic fluid flows into the collar from the oil hole in the peas through the check valve.

[0005]

[Problems to be solved by the device]

 However, in the oil lock mechanism of the conventional hydraulic shock absorber described above, it is necessary to secure a fitting length between the pierce and the collar to some extent, and the basic length becomes long. Furthermore, since the piece and the collar slide against each other on the metal, scratches, scratches, abnormal noise, etc. occur, which reduces durability and reliability. Moreover, when the axis of the piece and the collar are misaligned, the operability is reduced. Has the disadvantage of becoming worse.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention slidably fits a free piston that is biased upward by a spring into a bottomed tubular member, and moves upward from the bottom center of the bottomed tubular member. A center pin with a tapered tip is provided, and a through hole is formed in the free piston so that this center pin can be inserted. And a hollow portion capable of accommodating the center pin is formed in the pressing member.

[0007]

[Action]

 At the end of the compression stroke, the pressing member provided on the piston rod abuts against the free piston and presses against the urging force of the spring to lower the free piston, and the tip of the center pin facing the through hole of the free piston is tapered. Since the clearance is gradually reduced, the damping force gradually increases according to the position of the piston rod, and finally the free piston seals the hydraulic oil in the bottomed tubular member. Since the oil lock is applied by the oil lock, the damping force of the oil lock changes smoothly.

[0008]

【Example】

 Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a sectional view of a main part of a hydraulic shock absorber having an oil lock mechanism to which the present invention is applied, FIG. 2 is a sectional view of a main part of the hydraulic shock absorber in an oil-locked state, and FIG. 3 is a schematic view of the present invention. It is a principal part sectional drawing of another Example.

In the hydraulic shock absorber, a cylinder 2 is erected in an outer tube 1 having a cylindrical shape with a bottom, a piston rod 3 is inserted into the cylinder 2 from above, and a lower end portion of the piston rod 3 has a cylinder 2 inside. A piston 4 that is in sliding contact with the peripheral surface is fixed, and a compression side oil passage 5 for generating a damping force and an extension side oil passage (not shown) are formed in this piston 4 to open and close these compression side oil passages 5. A valve 7 and an expansion valve 8 that opens and closes the expansion oil passage are installed.

A bottom valve mechanism 10 is provided at the bottom of the outer tube 1 (lower part of the cylinder 2), and the bottom valve mechanism 10 forms a compression side oil passage and an extension side oil passage 13 in the bottom piece 11. Then, the valve 14 for opening / closing the compression side oil passage and the valve 15 for opening / closing the extension side oil passage 13 are fixedly mounted by bolts 16. A collar 17 which is a bottomed tubular member is provided on the bottom piece 11 of the bottom valve mechanism 10, and an oil for communicating the cylinder lower chamber and the reservoir chamber 18 to the collar 17 through the bottom valve mechanism 10. It forms the path 19.

A free piston 21 is slidably fitted in the collar 17 and is biased upward by a spring 22 provided between the collar 17 and the bottom. A seal ring 23 is fitted on the outer peripheral surface of the free piston 21, an oil hole 25 is formed, and a check valve 26 for opening and closing the oil hole 25 is provided between the spring 28 and a locking ring 27. I am wearing it by pushing it. Further, a stopper ring 30 of the free piston 21 is fitted on the upper part inside the collar 17.

Further, at the center of the bottom of the collar 17, a center pin 31 having a tapered tip 31a is formed integrally with the collar 17, and a through hole 32 is formed at the center of the free piston 21. Then, the bush 33 is fitted on the inner peripheral surface, and the tip portion 31a of the center pin 31 is exposed in the bush 33.

On the other hand, a lower end portion of the piston rod 3 is extended to form a pressing portion 35 for contacting and pressing the free piston 21 at the end of the compression stroke, and a rubber ring 36 is formed on the outer peripheral surface of the lower end of the pressing portion 35. A hollow portion 37 capable of accommodating and accommodating the center pin 31 is formed in the pressing portion 35, and an oil passage 38 that communicates the inner portion of the hollow portion 37 with the cylinder lower chamber is formed.

The operation of the oil lock mechanism of the shock absorber configured as described above will be described. When the piston rod 3 descends from the state shown in FIG. 1 in the compression stroke, the working oil corresponding to the entering volume of the piston rod 3 flows from the cylinder lower chamber through the oil passage 19 and the compression side oil passage of the bottom valve mechanism 10 to the reservoir. It flows into the chamber 18.

At this time, the pressing portion 35 descends as the piston rod 3 descends, and at the end of the compression stroke of the piston rod 3, the rubber ring 36 of the pressing portion 35 abuts on the upper surface of the free piston 21 and further. As the piston rod 3 descends, the free piston 21 is pushed down against the urging force of the spring 22, while the center pin 31 is housed in the hollow portion 37 of the pressing portion 35, as shown in FIG.

As the free piston 21 descends in this way, initially the hydraulic oil in the collar 17 flows into the cylinder lower chamber from the clearance between the bush 33 of the free piston 21 and the tip portion 31a of the center pin 31, Since the tip portion 31a of the center pin 31 is formed in a tapered shape, the clearance is gradually reduced according to the position of the piston rod 3 and the damping force is gradually increased, and the free piston 21 is tapered in the center pin 31. When descending beyond the tip 31a, the working oil is contained in the collar 17 and becomes in an oil lock state. As a result, the oil lock is not applied suddenly, but the oil lock is applied smoothly and the feeling is improved.

Then, from this state, the piston rod 3 rises in the rebound direction and the pressing portion 35 separates from the free piston 21, the free piston 21 rises by the urging force of the spring 22, and at this time, the check valve 26 opens. The hydraulic oil is replenished into the collar 17 through the oil hole 25.

Next, in another embodiment shown in FIG. 3, the center pin 31 is integrally formed with the bolt 16 of the bottom valve mechanism 10, and the collar 17 is provided so as to extend upward. is there. In this way, the bottom valve mechanism 10 can be made into a cartridge.

[0019]

[Effect of the device]

 As described above, according to the present invention, the free piston is slidably fitted in the bottomed tubular member, and the oil piston is locked by pressing the free piston at the end of the compression stroke. At the same time, since the tapered center pin is inserted into the through hole of the free piston, the damping force gradually increases when the oil is locked, and a sudden rise of the damping force is prevented, improving the feeling.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a hydraulic shock absorber having an oil lock mechanism to which the present invention is applied.

FIG. 2 is a sectional view of an essential part of the hydraulic shock absorber in an oil-locked state.

FIG. 3 is a sectional view showing the main part of another embodiment of the present invention.

[Explanation of symbols]

1 ... Tube, 2 ... Cylinder, 3 ... Piston rod, 4
... Piston, 10 ... Bottom valve mechanism, 11 ... Bottom piece, 17 ... Collar (bottomed cylindrical member), 21 ... Free piston, 22 ... Spring, 31 ... Center pin, 32
... through hole, 35 ... pressing part, 37 ... hollow part.

Claims (2)

[Scope of utility model registration request] 1. A shock in which a bottomed tubular member is disposed at the bottom of a lower chamber of a cylinder, and hydraulic oil is locked in the bottomed tubular member at the end of the compression stroke of the piston rod to lock the oil. In the oil lock mechanism of the absorber, a free piston, which is biased upward by a spring, is slidably fitted in the bottomed tubular member, and the free piston is upwardly moved from the bottom center of the bottomed tubular member. A center pin having a tapered tip is provided, and a free piston is provided with a through hole through which the center pin can be inserted.
Further, at the end of the compression stroke, a pressing member for contacting and pressing the free piston is provided at the lower end of the piston rod,
The oil lock mechanism of the hydraulic shock absorber, wherein the pressing member has a hollow portion capable of accommodating the center pin. 2. The oil lock mechanism for a hydraulic shock absorber according to claim 1, wherein the center pin is integrally formed with a bolt of the bottom valve.