JPS609476Y2 - hydraulic shock absorber - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of hydraulic shock absorbers such as front forks installed on two-wheeled vehicles and four-wheeled vehicles. This invention relates to a hydraulic shock absorber which is slidably inserted into the hydraulic shock absorber.

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 an inner tube at the tip of the hollow pipe. An auxiliary piston that slides in the tube, and a piston that slides on the hollow pipe below the inner tube, are provided, and these outer tube, inner tube, hollow pipe, auxiliary piston, and piston are used when the hydraulic shock absorber is extended. An upper chamber and a lower chamber are formed that generate a damping force.

During the compression operation in which the inner tube descends against the spring, oil is sucked into the upper chamber from the lower chamber through the check valve disposed on the piston, and oil is sucked into the upper chamber by the volume of the inner tube entering the lower chamber. The oil is discharged from the hole through the hollow pipe into the oil sump chamber.

In addition, during the extension operation in which the inner tube rises, a damping force is generated by discharging the oil in the upper chamber into the hollow pipe through the orifice, and at the same time, the insufficient oil amount corresponding to the protruding volume of the inner tube in the lower chamber is absorbed into the oil sump chamber. more compensated in hollow pipes and through through holes.

Furthermore, when the inner tube is at its maximum extension, the piston passes through the orifice and the upper chamber is in a hydraulically locked state to alleviate the shock, and even at its maximum compression, the hollow body at the lower end of the inner tube fits into the oil hole rod. This puts the lower chamber into a hydraulically locked state and cushions the impact.

In a hydraulic shock absorber configured in this way, the flow rate of oil from the hollow pipe to the oil reservoir during compression operation is extremely high, causing the oil to blow up into the air chamber above the oil reservoir, causing the oil to resist the spring. This can cause the oil level to fall below the bottom, and conversely, when the extension is activated, the oil in the oil reservoir chamber is rapidly sucked into the hollow pipe. This causes air to be drawn into the oil, and oil and air to mix.

As a result of the oil mixed with air flowing into the upper and lower chambers during expansion, the resistance through the orifice decreases, making it impossible to obtain the desired damping force, or compressing the air in the pond, causing the hydraulic shock absorber to reach its maximum level. It had drawbacks such as a decrease in shock-absorbing ability during expansion and contraction.

The present invention focuses on the fact that the oil volume change due to the large protrusion of the inner tube is compensated for in the oil sump chamber. To provide a hydraulic shock absorber which prevents air from entering.

The embodiment shown in FIGS. 1 and 2 will be described below.

In the embodiment shown in FIG. 1, the main body has an inner tube 2 slidably inserted into an outer tube 1 as in the conventional case, and a hollow pipe 3 extending from the bottom of the outer tube 1 into the inner tube 2. In addition, an auxiliary piston 4 is provided at the tip of the hollow pipe 3 to slide into the inner tube 2, and a piston 5 is provided below the inner tube 2 to slide into the hollow pipe 3. 1. Inner tube 2. Hollow pipe 3
, the auxiliary piston 4 and the piston 5 define a chamber A and a chamber B that generate damping force when the hydraulic shock absorber is extended, and above the auxiliary piston 4 there is an oil reservoir chamber C and an air chamber that communicate with the inside of the hollow pipe 3. is divided.

A spring 6 is interposed in the liquid chamber A, which acts against the extension when the inner tube 2 is extended and the piston 5 reaches its maximum extension. is built in to generate damping force during extension.

An orifice 7 is bored in the lower part of the hollow pipe 3 to communicate the liquid chamber B with the inside of the hollow pipe 3, and this orifice 7 generates a damping force on the pressure side when the main body is used alone. .

A bracket 8 is provided on the lower outer side of the outer tube 1, and the outer tube 1
can be fixed to the wheel side.

A hole 9 is bored in the lower part of the outer tube 1, a pipe joint 10 is connected to this hole, and an accumulator 12 is connected to this pipe joint 10 via a hose 11, and this accumulator 12 is connected to the outer tube 1. It is held in a detachable manner by a fixing band 13.

The accumulator 12 can be used as a hydraulic shock absorber without being attached, and if the accumulator 12 is not connected, a plug may be sealed in the hole 9.

In the above buffer, when the inner tube is compressed, the liquid chamber B contracts and the liquid chamber A expands.

At this time, the oil in the liquid chamber B flows into the expanding liquid chamber A through the valve provided in the heavy stone 5, and the oil corresponding to the plunge volume of the inner tube 2 flows into the internal air chamber of the accumulator 12 and into the air chamber above the oil reservoir chamber C. In particular, the amount of oil flowing into the oil sump chamber C through the orifice 7 is significantly reduced compared to conventional models of this type. Mixing with air is prevented without blowing up into the air chamber.

Also, when the inner tube 2 is extended, the liquid chamber A contracts, a damping force is generated by the valve in the piston 5, and the liquid chamber B
is enlarged due to the volume change when the inner tube 2 is expanded, but oil is sucked in from the accumulator 12 side through this gap 9, and the oil level is prevented from falling below the bottom without affecting the oil reservoir chamber C.

As described above, the change in oil amount due to the change in volume of the inner tube 2 during expansion and contraction is compensated for by the accumulator 12, thereby preventing air from entering the pond and causing the oil level to drop below the bottom.

In addition, if a reduction in damping force due to air intrusion is acceptable, the accumulator 12 can be removed and the hole 9 plugged to allow it to be used alone.

FIG. 2 shows another embodiment in which a side tank is fixed instead of the accumulator 12.

That is, the inner tube 16 is slidably inserted into the outer tube 14 via the piston 15, the hollow pipe 18 is inserted into the inner tube 16 from the lower partition member 17 of the outer tube 14, and the piston 15 is inserted into the upper and lower parts. Two liquid chambers E.

A liquid chamber G is defined below the partition member 17.

A through hole 19 is provided in the partition member 17 to communicate the liquid chambers F and G, and a plate valve 20 having an orifice is provided at the end of the through hole 19 so as to be openable and closable.

A sleeve 21 is screwed onto the hollow pipe 18, and a through hole 22 is formed in the sleeve 21 to communicate the liquid chamber G with the oil reservoir chamber above the hollow pipe.

A bracket 23 and a side tank 24 are connected to the outside of the outer tube 14, and the outer tube 14 is connected to the wheel side via the bracket 23.

A free piston 25 is slidably fitted into the side tank 24, and the free piston 25 partitions an air or gas chamber H and a liquid chamber I, and the liquid chamber 2 is connected to the outer tube 14.
They communicate through a through hole 26 bored downward.

In the above buffer, when the inner tube 16 is compressed, the liquid chamber F
The oil flows out into the liquid chamber G through the orifice of the plate valve 20, and at this time a damping force on the pressure side is obtained.

Further, the oil introduced into the liquid chamber G flows out from the through hole 26 into the liquid chamber 2, and moves the free piston 25 toward the air chamber H side.

For this reason, the change in oil amount due to the plunge volume caused by the descent of the inner tube 16 is compensated for in the air chamber above the oil reservoir chamber of the inner tube 16 and the air chamber H via the free piston 25, as described above. , especially the hollow pipe 18
The amount of hydraulic oil passing through the chamber is reduced, and no oil is blown up from the oil sump chamber to the air chamber.

Also, when the inner tube 16 extends, the oil in the liquid chamber E flows out into the liquid chamber F through the valve in the piston 15, and at this time, a damping force on the extension side is generated. The oil I pushes open the plate valve 20 and flows out, and at this time the free piston 25 moves to the liquid chamber (2) side.

Since the liquid chamber (2) is isolated from the air chamber (H) by the free piston 25, even if oil is suddenly sucked in, air will not be mixed into the pond.

As described above, the present invention has an oil reservoir chamber and an air chamber in the upper part of the inner tube, and a tank having an air chamber independent from the air chamber of the inner tube is provided on the outside of the outer tube. The volume of oil is compensated by the two air chambers mentioned above, and since the amount of oil flowing into the oil reservoir is small, the oil in the oil reservoir does not blow up into the air chamber in the inner tube, thus reducing the oil level mixed with air. In addition, the air chamber on the tank side only compensates for the wall thickness of the inner tube, so it can be small, and the air chamber of the inner tube can also be small, so the length of the inner tube and The diameter can be made smaller.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of a hydraulic shock absorber according to one embodiment of the present invention, and FIG. 2 is a longitudinal sectional side view, partially cut away, of a hydraulic shock absorber according to another embodiment. 1.14...Outer tube, 2,16...
...Inner tube, 3,18...Hollow pipe, 12...Accumulator, 24...
... Tank, 25 ... Free piston, G,
■...Liquid chamber, H...Air chamber.

Claims (3)

[Scope of utility model registration request] (1) Insert the inner tube, which has an oil reservoir chamber and an air chamber at the top, into the outer tube so that it can slide freely.
In a hydraulic shock absorber in which a hollow pipe is inserted from the lower part of the outer tube toward the inner tube, a tank is provided with an air chamber formed outside the outer tube independent of the air chamber inside the inner tube. The air chamber in this tank is connected to the liquid chamber in the outer tube,
A hydraulic shock absorber in which each air chamber compensates for changes in volume due to the entry and exit of the inner tube. (2) The hydraulic shock absorber according to claim (1) of the utility model registration, in which an accumulator is detachably disposed as a tank. (3) Utility model registration claim No. 1 in which a free piston is slidably fitted into a tank, the free piston partitions an air chamber and a liquid chamber, and the liquid chamber is communicated with a liquid chamber in an outer tube. The hydraulic shock absorber described in (1).