JPH09177862A - Hydraulic buffer with solenoid direct acting valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform operation of a hydraulic buffer at both compression and expansion processes by coupling a poppet valve, controlling a damping force constantly under environment of working oil on the low pressure side, directly to a solenoid. SOLUTION: In a hydraulic buffer 1 formed in such a manner that oil passages 11 and 12 through which two oil chambers 2a and 2b partitioned in a cylinder 2 from each other by a piston 3 are intercommunicated are formed in the two oil chambers 2a and 2b. A poppet valve 9 to regulate the opening of the oil passage 11 is coupled directly to a solenoid 7 for operation, a small oil chamber 13 is formed between the poppet valve 9 and the solenoid 7. The small oil chamber 13 is communicated to the two oil chambers 2a and 2b, partitioned from each other in the cylinder 2, through check valves 15 and 17 so that the small chamber is normally cut off from an oil chamber on the high pressure side and communicated with an oil chamber on the low pressure side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic shock absorber used as a shock absorber for a cushion in a vehicle suspension, and more particularly to a hydraulic shock absorber of a type in which a damping force is automatically adjusted according to changes in the running state of the vehicle. The present invention relates to a hydraulic shock absorber.

[0002]

2. Description of the Related Art In a hydraulic shock absorber used as a shock absorber for a vehicle suspension, the inside of a cylinder is divided into two in order to generate a predetermined damping force according to a running state.
In addition to the throttle provided on the piston itself that defines the two oil chambers,
An oil passage that connects the two oil chambers is separately provided, a valve that changes the opening of the oil passage is installed, and the valve is actuated according to changes in the running state of the vehicle. It has been conventionally practiced to adjust the damping force of the whole by changing the throttle according to the road.

[0003]

By the way, in the above-described variable damping force type hydraulic shock absorber, the two oil chambers are provided so as to communicate with each other so that the damping force can be arbitrarily widened. It is conceivable that a poppet valve is installed to adjust the opening of the oil passage and that the poppet valve is operated by a proportional solenoid that is controlled according to changes in the running state of the vehicle. There is.

In this case, if a hydraulic system for operating the valve is provided between the solenoid and the poppet valve, and the valve is indirectly operated by the hydraulic pressure generated by the movement of the solenoid, the current flowing through the solenoid changes. Since there is a problem in the responsiveness of the valve operation from the above, it is considered that the poppet valve is directly connected to the solenoid to operate without providing a hydraulic system for operating the valve.

However, if the poppet valve is directly connected to the solenoid in this manner, the solenoid and the poppet valve are operated in the hydraulic oil of the hydraulic shock absorber, so that the hydraulic shock absorber operates in the compression stroke in the operating environment of the poppet valve. Although there is no problem as is the low-pressure side operating oil, in the expansion stroke of the hydraulic shock absorber, the operating environment of the poppet valve becomes the high-pressure side operating oil, and the resistance of the operating oil causes the responsiveness of the valve operation by the solenoid to increase. There is a problem of getting worse.

[0006]

In order to solve the above problems, the present invention provides two oil chambers defined by a piston in a cylinder as described in claim 1 above. In a hydraulic shock absorber provided with an oil passage communicating between both oil chambers, a poppet valve for adjusting the opening of the oil passage is provided so as to be directly connected to the solenoid to operate.
A small oil chamber is defined between the poppet valve and the solenoid, and the small oil chamber is defined in the cylinder.
It is characterized in that the three oil chambers are communicated with each other through a check valve so that they are always disconnected from the high pressure side oil chamber and communicated with the low pressure side oil chamber.

Further, in the hydraulic shock absorber with the solenoid direct-acting valve according to the above-mentioned claim 1, the above-mentioned claim 2
As described above, an oil passage that connects the oil chambers to each other is provided in the fixed shaft portion of the piston that defines the inside of the cylinder into two oil chambers, and a poppet valve for adjusting the opening of the oil passage is provided. ,
It is characterized in that it is provided so as to be directly connected to a solenoid to operate.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a hydraulic shock absorber with a solenoid direct acting valve according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a structure around a piston of a hydraulic shock absorber of the present embodiment used as a shock absorber in a suspension of a vehicle such as an automobile or a motorcycle, and shows the entire hydraulic shock absorber 1. Although not shown, the cylinder 2 forming a closed space
A piston rod 4 provided with a piston 3 near the tip is inserted into and out of the cylinder from one end of the cylinder 2, and the other end of the cylinder 2 and the end of the piston rod 4 outside the cylinder are inserted. And a mounting portion to the vehicle body is formed respectively.

In the inside of the cylinder 2 of the hydraulic shock absorber 1, the fluctuation amount of the oil amount in the cylinder 2 due to the change in volume of the piston rod 4 or the temperature change is excluded, or the fluctuation amount of the oil amount is in the cylinder 2. It is filled with hydraulic oil for generating a damping force in a state where it can come in and out from the inside, and the hydraulic oil space in the cylinder 2 is defined by two oil chambers 2a and 2b with the piston 3 as a boundary. .

In such a hydraulic shock absorber 1, as shown in FIG. 1, the piston 3 is formed in the solenoid accommodating portion 5 integrally formed at the tip portion of the piston rod 4 itself and in the solenoid accommodating portion 5. It is fixedly installed to the piston rod 4 via a rod tip member 6 fixed to the housing portion 5 so as to close the housing space.

That is, the solenoid accommodating portion 5 is formed by expanding the diameter of the distal end portion of the piston rod 4 to form a space for accommodating the solenoid 7 therein, and the distal end side is open. A screw is formed on the inner peripheral surface near the end, and the inside of the accommodating portion 5 and the hollow center portion 4a of the piston rod 4 communicate with each other so that the cord 8 for sending an electric current can be connected to the accommodated solenoid 7. ing.

The solenoid 7, which is inserted from the open end of the solenoid housing portion 5 and installed in the housing space, is a proportional solenoid whose movement amount is changed according to the magnitude of the current flowing through the cord 8. Then, the magnitude of the current applied to the solenoid 7 by the code 8 is controlled by the CPU based on the detection of the running state of the vehicle by the vehicle attitude sensor, the throttle sensor, and the like.

The rod tip member 6 is composed of a large-diameter base portion 6a, a medium-diameter intermediate portion 6b, and a small-diameter piston fixing shaft portion 6c, and is fixed to the solenoid accommodating portion 5. Inside the base portion, The poppet valve 9 directly connected to the solenoid 7 is slidably held across 6a and the intermediate portion 6b, and the piston 3 is fitted and fixed to the outer periphery of the piston fixing shaft portion 6c.

For fixing the rod tip member 6 to the solenoid accommodating portion 5, a screw is formed on the outer peripheral surface near the tip of the base portion 6a of the rod tip member 6 and the piston fixing shaft portion 6c. The rod tip member 6 is detachably fixed to the solenoid storage portion 5 in a state in which the solenoid storage portion 5 is closed by screwing the surface screw with the screw on the inner peripheral surface near the tip of the solenoid storage portion 5. .

An oil passage 11 is formed in the rod tip member 6 so as to penetrate in the axial direction from the piston fixing shaft portion 6c to the intermediate portion 6b. The oil passage 11 is laterally extended from the oil passage 11 at the intermediate portion 6b. An oil passage 12 that connects 11 to the oil chamber 2b is formed, and as a result, the oil passage 11 and the oil passage 12 connect the oil chamber 2a and the oil chamber 2b.

A poppet valve 9 for changing the opening degree of the oil passage 11 is provided at a connection portion between the oil passage 11 and the oil passage 12 which connect the oil chamber 2a and the oil chamber 2b to each other. The poppet valve 9 is formed in a stepped shape having a large diameter portion that is in sliding contact with the rod tip member 6 and a small diameter portion that closes the oil passage 11.
It is supported by 0 and is directly pushed by the solenoid 7, and is slidably held over the intermediate portion 6b and the base portion 6a.

Between the base portion 6a of the rod tip member 6 and the solenoid 7, a small oil chamber 13 is defined by the base portion 6a, the solenoid 7 and the poppet valve 9 and also communicates with the moving space of the solenoid 7. The small oil chamber 13 and the oil chamber 2b
An oil passage 14 for communicating with the base 6a is formed in the base portion 6a, and an oil passage 16 for communicating with the small oil chamber 13 and the oil passage 11 includes a base portion 6a, an intermediate portion 6b, an interposed member 24, and a piston fixing shaft portion 6c. It is formed across

A check valve 15 acting as an equalizer is installed in the oil passage 14 for connecting the small oil chamber 13 and the oil chamber 2b, and an oil passage 16 for connecting the small oil chamber 13 and the oil passage 11 is provided. Also, a check valve 17 that works as an equalizer is installed.

The piston 3 is provided with a plurality of oil passages 3a and 3b, which serve as throttles, on the periphery of the piston fixing shaft portion 6c of the rod tip member 6, and plate valves 21 and 22 are arranged on both sides thereof. In this state, the piston fixing shaft portion 6c is fitted and inserted so as to be positioned at the step portion of the piston fixing shaft portion 6b and the intermediate portion 6b via the ring-shaped interposed members 23 and 24 on both sides. , Are fixed by tightening the bolts 25 by screwing.

In the hydraulic shock absorber 1 as described above, during the compression stroke, the piston 3 moves in the direction of arrow A with respect to the cylinder 2, as shown in FIG. The hydraulic oil on the side of the oil chamber 2a that has flowed flows to the side of the oil chamber 2b through the oil passage 3a of the piston 3, and from the oil passage 11 provided on the rod tip member 6 to the oil passage 1
Through 2 to the oil chamber 2b side.

During the extension stroke, as shown in FIG. 3, the piston 3 moves in the direction of arrow B with respect to the cylinder 2, so that the operation of the oil chamber 2b, which is compressed by the piston 3 and has a high pressure, is performed. The oil flows to the oil chamber 2a side through the oil passage 3b of the piston 3, and also flows from the oil passage 12 provided in the rod tip member 6 to the oil chamber 2a side through the oil passage 11.

In either compression or expansion stroke, the current flowing through the cord 8 is changed by the control of the CPU based on the detection of the running state of the vehicle, so that the magnitude of the current is changed. Actuating solenoid 7
Since the opening degree of the oil passage 11 is changed via the poppet valve 9 that is directly pushed by, the damping force of the entire hydraulic shock absorber 1 becomes suitable for the running state of the vehicle.

At this time, the oil passage 14 and the oil passage 16 are provided to the small oil chamber 13, and the check valves 15 and 17 that act as equalizers are provided to the oil passages 14 and 16, respectively. During the compression stroke, the oil passage 16 that communicates with the oil passage 11 that communicates with the oil chamber 2a where the working oil has a high pressure.
Check valve 17 is closed, and the check valve 15 of the oil passage 14 communicating with the oil chamber 2b on the side where the hydraulic oil has a low pressure is opened. The operating oil constantly flows into and out of the low pressure side oil chamber 2b.

Also, during the extension stroke, the check valve 1 of the oil passage 14 communicating with the oil chamber 2b on the side where the working oil has a high pressure.
5 is closed, and the oil passage 1 is connected to the oil chamber 2a where the working oil has a low pressure.
The check valve 17 of the oil passage 16 communicating with 1 opens,
When the poppet valve 9 is operated by the solenoid 7, the hydraulic oil that has entered the small oil chamber 13 is always in the low pressure side oil chamber 2
It goes in and out of the oil passage 11 connected to a.

According to the hydraulic shock absorber 1 of the present embodiment as described above, the poppet valve 9 for changing the damping force by the oil passage 11 is supported by the set spring 10 and directly pushed by the solenoid 7. Since it is provided in such a state that the thrust force of the solenoid 7 is changed in proportion to the magnitude of the electric current flowing through the solenoid 7, the damping force is gradually changed like the conventional orifice passage variable type hydraulic shock absorber. Instead of changing the damping force, it is possible to arbitrarily change the damping force widely.

Moreover, the solenoid 7 and the poppet valve 9
The small oil chamber 13 defined between the two is disconnected from the oil chamber on the high pressure side and communicated with the oil chamber on the low pressure side in any case of the compression / expansion stroke, so that the solenoid 7 or Since the operating environment of the poppet valve 9 can be maintained on the low pressure side, the responsiveness of the poppet valve 9 can always be made good.

Further, since the poppet valve 9 is supported by the set spring 10, the solenoid 7
A constant damping force can be secured even if the current to the device is cut off, and it is not necessary to provide a special compensation mechanism.

Further, in the present embodiment, since the poppet valve 9 has the stepped shape having the large diameter portion and the small diameter portion, the characteristic ratio of the damping force change on each side of the compression / extension stroke should be constant. Therefore, the performance suitable for the shock absorber can be easily obtained.

Although one embodiment of the hydraulic shock absorber with a solenoid direct acting valve of the present invention has been described above, the present invention provides the oil passage 11 in the fixed shaft portion 6c of the piston 3 as described above, and the solenoid 7 is provided. And poppet valve 9 to cylinder 2
The present invention is not limited to the embodiment for a hydraulic shock absorber of a type built in the inside, but an oil passage that connects two oil chambers defined by the piston to the cylinder is provided in the outer cylinder outside the cylinder, and It is also applicable to a hydraulic shock absorber of external cylinder mounting type in which a damping force adjusting mechanism is installed.

[0031]

According to the hydraulic shock absorber with a solenoid direct-acting valve of the present invention as described above, the damping force is always kept in the environment of the hydraulic oil on the low pressure side in both compression and extension strokes of the hydraulic shock absorber. Since the poppet valve for controlling the valve can be operated by directly connecting it to the solenoid, the damping force can be changed over a wide range and the responsiveness when the damping force is changed is always good. It can be anything.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of a hydraulic shock absorber with a solenoid direct acting valve according to the present invention.

2 is a cross-sectional explanatory view showing a flow of hydraulic oil in a compression stroke of the hydraulic shock absorber with a solenoid direct acting valve shown in FIG.

3 is a cross-sectional explanatory view showing a flow of hydraulic oil in an extension stroke of the hydraulic shock absorber with a solenoid direct-acting valve shown in FIG.

[Explanation of symbols]

 1 Hydraulic shock absorber 2 Cylinder 2a Oil chamber 2b Oil chamber 3 Piston 6c Fixed shaft part of piston 7 Solenoid 9 Poppet valve 11 Oil passage 12 Oil passage 13 Small oil chamber 15 Check valve 17 Check valve

Claims (2)

[Claims] 1. A two-oil chamber defined by a piston in a cylinder is provided with an oil passage communicating between the two oil chambers, and a poppet valve for adjusting the opening of the oil passage is provided.
In the hydraulic shock absorber provided so as to be directly connected to the solenoid, a small oil chamber is defined between the poppet valve and the solenoid, and the small oil chamber is defined in the cylinder. A solenoid direct-acting valve, which is connected to each of the two oil chambers via a check valve so that the two oil chambers are always disconnected from the high-pressure side oil chamber and communicated with the low-pressure side oil chamber. Hydraulic shock absorber. 2. A fixed shaft portion of a piston which defines the inside of a cylinder into two oil chambers is provided with an oil passage communicating between the oil chambers.
The hydraulic shock absorber with a solenoid direct-acting valve according to claim 1, wherein a poppet valve for adjusting the opening of the oil passage is provided so as to be directly connected to the solenoid to operate.