JPS594191Y2 - Check valve device in hydraulic shock absorber - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a check valve device in a hydraulic shock absorber suitable for two- and four-wheeled vehicles.

In general, this type of hydraulic shock absorber has an outer tube disposed adjacent to the inner tube, and a piston that divides the upper and lower oil chambers is slidably inserted into the inner tube, and a lower oil chamber is inserted into the outer tube. The chamber and the upper gas chamber are divided, and the two lower chambers are communicated with each other through an orifice bored in the inner tube.

On the other hand, it is known that the piston is provided with damping valves on the expansion side and compression side, and the gas chamber is filled with pressurized gas of about 10 kg/cd.

In such a hydraulic shock absorber, when the piston rod moves toward the pressure side, the oil in the liquid chamber above the piston is throttled by the rebound damping valve of the piston portion and flows into the lower liquid chamber.

At this time, the pressure in the upper liquid chamber increases and a damping force is generated.

Further, as the volume of the lower liquid chamber increases, the hydraulic oil is replenished by the amount flowing from the upper liquid chamber and the amount flowing from the orifice.

During pressure-side operation, the oil in the lower liquid chamber of the piston is throttled by the pressure-side damping valve in the piston section and the orifice in the lower part of the cylinder, and flows into the upper liquid chamber and the liquid chamber below the gas chamber.

At this time, the pressure in the lower liquid chamber increases and a damping force is generated, and the replenishment of hydraulic oil accompanying the increase in the volume of the upper liquid chamber is filled by the amount flowing from the lower liquid chamber.

However, in the above-mentioned conventional hydraulic shock absorber, in order to increase the compression side damping force characteristics, the orifice drilled in the cylinder must also be made smaller.As a result, when the piston speed is high and the excitation cycle is high, the liquid chamber below the gas chamber The time required to send oil to the lower piston liquid chamber becomes shorter, leading to insufficient oil suction and disrupting the waveform of the damping force characteristics.

Furthermore, if the hydraulic shock absorber is left stationary for a long period of time, the oil level in the cylinder will drop and gas will enter.

When the next operation is performed in this state, the gas in this cylinder must be immediately sent to the gas chamber to fill the cylinder with oil.

Considering the process of sending gas here, when the piston rod extends, the gas in the upper piston liquid chamber passes through the communication hole in the bearing and returns to the gas chamber, and as the volume of the lower piston liquid chamber increases, hydraulic oil is replenished at the upper part of the piston. This is done by drawing in from the liquid chamber below the liquid chamber and gas chamber.

However, when the orifice is small or the pressure difference between the piston lower liquid chamber and the gas chamber lower liquid chamber is small, there is a problem that the replenishment flow rate is small and it takes time to return to normal.

In order to solve this problem, it is possible to increase the pressure in the gas chamber and increase the orifice area, but on the other hand, it may cause gas leakage due to defects in gas sealing, problems in handling the shock absorber, or problems at low temperatures. When the gas pressure decreases, the waveform of the damping force characteristic is disturbed due to the influence of this gas pressure.

Therefore, in order to solve the above problem without increasing the gas pressure, a method has been considered in which a check valve is installed at the bottom of the cylinder so that it opens when it is extended and closes when it is on the pressure side, but in the case of a hydraulic shock absorber, the basic length is shortened. If the check valve is provided on the bottom side of the cylinder because one of the purposes is to provide a check valve, not only will the basic length become longer by the bottom, but it will also be undesirable because it will cause processing problems and troublesome installation.

Furthermore, similar problems occur even in hydraulic shock absorbers that do not use a gas chamber and in those that utilize the orifice for generating damping force.

Therefore, the purpose of this invention is to shorten the basic length of the cylinder.
It is an object of the present invention to provide a check valve device for a hydraulic shock absorber that is easy to process and install.

In order to achieve this objective, the configuration of the present invention is such that a check valve made of a C-shaped cylinder is brought into contact with the inner circumferential surface of the inner tube.
The hydraulic shock absorber is characterized in that the inner tube has a communication hole facing the check valve, and the check valve has an orifice facing the communication hole.

An example of implementing the present invention will be described below with reference to the drawings.

When the hydraulic shock absorber according to the present invention is of a pressurized type as shown in FIG. The piston 3 is slidably inserted through the inner tube 1, and defines two upper and lower liquid chambers 4 and 5 within the inner tube 1.

A seal cover 6 is fitted above the bearing 2, a seal 7 is disposed within the seal cover 6, and a piston rod 3a passes through the bearing 2 and the seal 7 and projects to the outside.

An outer tube 8 is connected to the lower part of the seal cover 6 concentrically with the inner tube 1.
A lower cap 9 is fixed to the lower end of the tube, and a gas chamber 10 and a liquid chamber 14 below the gas chamber 10 are defined between the inner tube 1 and the outer tube 8.

Through holes 11 and 12 are bored in the bearing 2, and these through holes 11 and 12 communicate the liquid chamber 4 and the gas chamber 10, and the upper end of the gas chamber 10 of the through hole 12 (the left eye end in FIG. 1) A cap body 13 is interposed therein, and oil and gas leaking from the liquid chamber 4 when the piston 3 is extended are discharged from the cap body 13 into the gas chamber 10. It hangs down to the liquid chamber 14.

A passage 15 is vertically bored in the piston 3 to communicate the two liquid chambers 4 and 5, and a plate valve 16 for opening and closing the passage 15 is disposed at the upper end of the piston 3. An orifice bored in the plate valve 16 generates a damping force on the expansion side, and when on the compression side, the plate valve 16 is opened from the passage 15 to supply oil from the liquid chamber 5 to the upper liquid chamber 4.

A gas sealing port 17 is bored in the center of the lower cap 9,
An elastic ball 18 is interposed at the eye end of this filling port, and gas is sealed into the gas chamber 10 from the filling port via this ball 18. After that, the eye 19 is welded to close the filling port 17 and the gas is released. It is designed not to leak.

The liquid chambers 4 and 5 and the lower liquid chamber 14 of the gas chamber 10 are filled with hydraulic oil.

As shown in FIG. 2, a communication hole 21 is formed at the lower end of the inner tube 1 and has a relatively large opening area toward the open end.
The oil from the liquid chamber 14 can be easily sucked into the liquid chamber 5 side.

Further, inside the lower part of the inner tube 1, there is an elastic band-shaped C-shaped spring whose end is fixed by welding, for example, a check valve 23 made of C-shaped elastic thin plate spring steel as shown in FIG.
' is arranged elastically, and this check valve 23' comes into contact with the inner wall of the inner tube 1 by its elastic force, and this check valve 23' itself is opposite to the communication hole 21 and is Orifices 20' having a small inner diameter are bored, and the two liquid chambers 5.14 communicate with each other through these orifices 20' and the communication hole 21.

In Fig. 4, the communication hole is not cut out as in Fig. 2, but a relatively large diameter communication hole 24 is bored in the lower part of the inner tube 1, and the orifice 20' of the check valve 23' is opposed to this hole 24. It is what you use.

An orifice 20' is bored in the check valve 3' itself, and this orifice 20' is connected to the communication hole 21, 24 in FIGS. 2 and 4.
Since the inner diameter of the communicating holes 21 and 24 is larger than the orifice 20', the damping force on the compression side can be applied by the orifice 20', and conversely, on the rebound side, the check valve 23' can be applied. The oil in the liquid chamber 14 is caused to flow out to the liquid chamber 5 side through the communication hole 21 or 24 by bending.

In the above hydraulic shock absorber, when the piston 3 descends on the pressure side, the liquid chamber 5 contracts, and the upper liquid chamber 4 expands accordingly.
At this time, part of the oil in the liquid chamber 5 pushes open the valve 16 through the through hole 15 of the piston 3 and flows out into the liquid chamber 4. At the same time, part of the oil flows through the orifice 20' and the communication hole 21 or 24 into the liquid chamber below the gas chamber. 14, and at this time, a damping force on the compression side is generated due to the flow resistance of the orifice 20'.

On the other hand, on the expansion side, the liquid chamber 5 expands, the upper liquid chamber 4 contracts, and the oil in the liquid chamber 4 flows out to the liquid chamber 5 side through the orifice and through hole 15 of the plate valve 16, and the oil in the liquid chamber 4 flows out from the orifice of the plate valve 16. Generate capital reduction capacity on the growth side.

Also, at this time, the amount of oil is compensated for as the volume of the liquid chamber 5 increases by causing the oil in the liquid chamber 14 to push open the check valve 23' through the communication hole 21 or 24 and flow into the liquid chamber 5.

Therefore, in the above-mentioned shock absorber, since the damping force on the pressure side is obtained at the orifice 20', the damping force is generated without being influenced by the gas pressure in the gas chamber 10, and the check valve 23' is built in the inner tube 1. Moreover, the orifice is 20'
Since it is drilled in the check valve 3' itself, it requires less space than the conventional compression side damping force generator, which allows for a sufficient stroke of the hydraulic shock absorber and increases the dimensions of the hydraulic shock absorber. It's not necessary.

FIG. 5 shows another embodiment in which a plurality of communication holes 25.2B are bored in the inner tube 1, and C-shaped holes 25.2B are formed inside and outside the lower part of the inner tube 1, such as a C-shaped hole.
The elastic plate-shaped check valves 27 and 2B of the mold are brought into elastic contact, and the ends of these check valves 27 and 28 are fixed with rivets 29.
, fixed to the inner tube 1 side by other methods, and an orifice 30 facing the communicating hole 26 is bored in the inner check valve 27, and communicating holes 25.2 on each inner tube 1 side are formed.
6 is normally closed by two check valves 27, 28, respectively.

Therefore, when the internal pressure of the liquid chamber 5 increases on the pressure side, the check valve 28 outside the orifice 30 and the communication hole 26
is pushed open and flows out to the liquid chamber 14 side, and the orifice 30
The damping force on the compression side is generated by the action of

Further, as the volume of the liquid chamber 5 increases during extension, oil in the liquid chamber 14 pushes open the inner check valve 27 and is sucked into the liquid chamber 5 side through the communication hole 25.

As described above, in the present invention, orifices for generating damping force are bored in the check valves 23' and 27, and these orifices are arranged to face the communicating holes bored in the inner tube 1 side. Since the orifice generates the compression damping force and the check valve is opened during the rebound side to facilitate oil suction through the communication hole, the valve device such as the base valve that generates the compression damping force is installed at the bottom of the inner tube. There is no need to provide it in the axial direction, the basic length of the inner tube is shortened by the length of the valve device omitted, and the damping force characteristic of the orifice is obtained by the orifice, so the damping force characteristic can be improved and stabilized.

Furthermore, since the check valve provided with the orifice is simply brought into contact with the inner circumferential surface of the cylinder, the number of parts is small, the structure is simple, workability and installation are improved, and it is advantageous in terms of cost.

[Brief explanation of the drawing]

The attached drawings relate to embodiments of the present invention, and FIG. 1 is a longitudinal side view of a hydraulic shock absorber, FIG. 2 is a partially cutaway longitudinal side view of an inner tube, FIG. 3 is a cross-sectional plan view of a check valve, and FIG. 4
The figure is a partially cutaway vertical side view of another embodiment of the inner tube, and FIG. 5 is a cross-sectional plan view of another embodiment of the check valve. 1...Inner tube, 3...Piston, 4゜5...Liquid chamber, 8...Outer tube, 20', 30...・Orifice,
21.24...Communication hole, 23', 27...
... Check valve.

Claims (5)

[Scope of utility model registration request] (1) The damping force is exerted at each time by the expansion and contraction movement of the piston that separates the two liquid chambers, and consists of an elastic band-shaped C-shaped ring on the inner circumferential surface of the inner tube, which is disposed alongside the outer tube. An orifice that generates a damping force when the check valve is operated on the compression side in a hydraulic shock absorber in which a check valve is brought into contact with the inner tube and a communication hole is bored in the inner tube facing the check valve to allow oil to be sucked in when the oil is sucked in when the check valve is on the compression side. 1. A check valve device for a hydraulic shock absorber, which is provided with a hole facing the communication hole. (2) A check valve device in a hydraulic shock absorber according to claim 1, wherein the inner diameter of the orifice is smaller than the communication hole. (3) A check valve device in a hydraulic shock absorber according to claim 1, wherein the communication hole is a notch. (4) A check valve device in a hydraulic shock absorber according to claim 1, wherein one end of the check valve is individually welded to the inner tube. (5) A check valve device in a hydraulic shock absorber according to claim 1, wherein one end of the check valve is fixed to the inner tube with a rivet.