JPS5912439Y2 - hydraulic shock absorber - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a hydraulic shock absorber mounted on two-wheeled vehicles, four-wheeled vehicles, etc.

Conventionally, this type of hydraulic shock absorber has an inner tube slidably inserted into an outer tube, a hollow pipe protruding from the bottom of the outer tube into the inner tube, and a tip of the hollow pipe. An auxiliary piston that slides on the inner circumference of the inner tube, and a piston that slides on the outer periphery of the hollow pipe are provided below the inner tube, and these outer tube, inner tube, hollow pipe, auxiliary piston, and piston act as a hydraulic shock absorber. It features an annular chamber that generates a damping force during extension.

Moreover, in conventional shock absorbers of this type, the annular chamber is filled with hydraulic oil by using a hollow rod and flowing the hydraulic oil through the damping hole bored inside the hollow rod and at the time of assembling the front fork. .

In the conventional hydraulic shock absorber constructed in this way, when the amount of oil discharged during compression operation that is equivalent to the volume that entered the inner tube passes through the hollow pipe and returns to the oil reservoir chamber, the oil is removed. The air is blown up into the air chamber above the oil sump chamber at an extremely high speed, or the stirring action within the oil sump chamber draws air into the hydraulic oil, causing the oil and air to mix.

As a result of the hydraulic oil mixed with air flowing into the annular chamber during extension, the passage resistance of the orifice decreases and the desired damping force cannot be obtained, or the hydraulic shock absorber is compressed due to the air mixture in the hydraulic oil. However, it has disadvantages such as a decrease in shock-absorbing ability at the time of maximum expansion and contraction.

For this reason, the present applicant has already provided another compensation chamber in addition to the internal oil reservoir chamber to compensate for the change in oil amount due to the protrusion of the inner tube, and has also installed a blind rod or solid rod instead of the conventional hollow rod. A hydraulic shock absorber was developed that uses rods to prevent oil from blowing up and to prevent mixture of oil and air. Since the inside cannot be used as an oil passage, it is extremely difficult to fill and supply oil to the annular oil chamber etc. when assembling the shock absorber.

Therefore, the purpose of the present invention is to improve a hydraulic shock absorber using this type of blind rod, which is advantageous in terms of its structure to prevent oil from blowing up, and to provide a front fork that allows oil to be easily filled and supplied to the annular oil chamber or separate chamber during assembly. Our purpose is to provide hydraulic shock absorbers such as:

The embodiment will be described below with reference to the drawings.

In the hydraulic shock absorber of the present invention, an inner tube 2 is slidably inserted into an outer tube 1 as in the conventional case, and a blind rod 3 is provided protruding from the bottom of the outer tube 1 into the inner tube 2. .

Further, below the inner tube 2, a piston 4 in contact with the inner circumferential surface of the outer tube 1 and a check valve 5 for restricting the flow in one direction between the chambers above and below the piston 4 are provided, respectively.
These outer tube 1, inner tube 2, rod 3, and check valve 5 define chambers 6 and 7 that generate the damping force of the hydraulic shock absorber.

Next, an air chamber 10 and an oil chamber 11 are partitioned by a slidable partition member 9 in a case 8 fixedly installed below the outer tube 1.
The chamber 10 is isolated from oil to compensate for changes in oil amount due to the protruding volume of the inner tube 2.

An oil reservoir air chamber 12 is provided above the inner tube 2, and lubricating oil is contained in the lower portion of this chamber 12.

Furthermore, a suspension spring is interposed within the chamber 12 to constantly push the inner tube 2 upward.

In the compression operation of the hydraulic shock absorber, oil corresponding to the volume of the inner tube enters into the chamber 11 from the hole 13, and in the extension operation, the oil flows into the chamber 1 side.
1 of oil is supplied to chamber 7 without resistance.

As the oil flows in and out of the chamber 11, the partition wall member 9 moves within the case 8 to compensate for the change in oil amount corresponding to the volume of the protruding inner tube 2.

In the embodiment, a free piston movable within the case 8 is used as the partition wall member 9, but a bellows made of a rubber material or the like may also be used.

Next, in the case of the present invention, a stocker 14 consisting of a nut or the like is fixed to the upper end of the rod 3 in place of the conventional auxiliary piston, and below this stopper 14 there are two upper and lower chambers 6,
A valve body 15 that partitions the valve body 12 is fitted loosely so as to be vertically movable, and this valve body 15 is always pressed against the lower surface of the upper stopper 14 by a lower spring 18 fixed to the rod 3, and is held in the valve closed state.

Also, there is a slight gap 1 between the inner circumference of the valve body 15 and the rod 3.
6 is shaped so that chambers 6 and 12 can be opened and closed.

A piston ring 17 having a check function is loosely fitted on the outer periphery of the valve body 15, and this piston ring 17 comes into sliding contact with the inner wall of the outer tube 1.

Two springs 19 and 20 are loosely fitted in series below the valve body 15, and one spring 20
acts as a negative spring.

Note that when the two springs 19 and 20 are arranged in series, the other spring 19 may be fixed to the valve body 15 and one spring 20 may be fixed to the other spring 19.

Also, two springs 19. 20 may be disposed in parallel in a loosely fitted state or in a state fixed to the valve body 15.

Furthermore, a hole 21 is bored in the inner tube 2, and this hole 2
1 communicates a chamber 22 provided between the inner tube 2 and outer tube 1 with the chamber 6 so that lubricating oil can be supplied.

In the hydraulic shock absorber of the present invention, chambers 6 and 7 are
When assembling the hydraulic shock absorber, remove the cap from the upper end of the inner tube, insert a tool, and forcefully press down the valve body 15 against the spring 18 to supply the specified amount of hydraulic oil. By injecting oil, the annular chamber 6 side can be filled with oil from the gap 16, and after being filled in this way, if the shock absorber is expanded and contracted several times, it will flow through the inner circumference of the check valve 5 into the chambers 6 and 7. Air and oil can be replaced to fill the tank with oil.

Note that the damping effect during operation is the same as that of the conventional one, so the details will be omitted.

Further, since the valve body 15 of the present invention is simply loosely fitted and supported on the outer periphery of the upper end of the blind rod, it is movable in the radial direction to follow the eccentricity of the rod 3, and the valve body 15 is able to move in the radial direction to accommodate the eccentricity of the rod 3. It is possible to prevent the so-called galling phenomenon from occurring between the parts.

As described above, in the hydraulic shock absorber of the present invention, since the valve body 15 is movably loosely fitted, even if the rod 3 is blind or solid, it is possible to easily fill and supply oil when assembling the rod 3. Furthermore, in terms of the damping function, it is possible to always exert a stable damping force, since the disadvantages caused by air intrusion, such as in conventional hollow rod type hydraulic shock absorbers, can be overcome.

[Brief explanation of the drawing]

The accompanying drawing is a partially cutaway vertical side view of a hydraulic shock absorber according to an embodiment of the present invention. 1... Outer tube, 2... Inner tube, 3... Rod, 14...
・Stopper, 15... Valve body, 16...
・Gap, 18...Spring.

Claims (2)

[Scope of utility model registration request] (1) An inner tube is inserted into the outer tube, and a separate chamber is provided at the bottom of the outer tube to compensate for changes in oil level due to the protrusion of the inner tube. A blind rod is erected, and above the rod a valve body that divides two upper and lower chambers is movably fitted loosely, and this valve body is constantly pressed against a stopper on the rod side by a lower spring. A hydraulic shock absorber configured such that a gap is formed between the valve body and the rod to communicate the two chambers only when the valve body is pressed down. (2) The hydraulic shock absorber according to claim 1, in which a nut is fixed to the tip of the rod as a stopper.