JPH049932B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a damping force adjustment structure for a hydraulic shock absorber, and in particular to a hydraulic shock absorber that is optimal for use in a hydraulic shock absorber that allows changing and adjusting the damping force. This invention relates to a damping force adjustment structure for a device.

[Conventional technology]

A proposal for a damping force adjustment structure for a hydraulic shock absorber that allows the damping force generated when the piston inside the cylinder slides to be changed continuously without steps is as follows:
Although various methods are possible, as a method for directly changing the deflection rigidity of a damping valve without using a control valve or the like, a method may be proposed in which a magnetic field is formed using a solenoid and a damping valve is interposed within the magnetic field. .

According to this proposal, by continuously changing the excitation to the solenoid, the flexural rigidity of the damping valve can be changed continuously, making it possible to continuously adjust the damping force as desired.

[Problem that the invention seeks to solve]

However, when using a solenoid as proposed above, if the solenoid is housed in the piston part of the cylinder or in the vicinity of the cylinder, the internal volume of the cylinder will increase. However, there is a problem in that the overall length of the hydraulic shock absorber itself is significantly increased and its diameter is significantly increased.

Therefore, a proposal may be made to arrange the solenoid outside the hydraulic shock absorber, but if such a solenoid is disposed outside the hydraulic shock absorber, it is necessary to form a magnetic path inside the hydraulic shock absorber. There is a problem in that the selection of materials for the hydraulic shock absorber affects all parts constituting the hydraulic shock absorber, and the room for selecting materials in consideration of the durability of the hydraulic shock absorber is extremely limited.

Therefore, in view of the above-mentioned circumstances, the present invention eliminates the use of a solenoid, and has a simple structure that enables effective continuous or stepwise change and adjustment of the damping force of a hydraulic shock absorber. The purpose is to provide a new structure.

[Means for solving problems]

In order to solve the above problems, the structure of the present invention includes a damping valve that can generate a desired damping force when the piston inside the cylinder slides, and a damping valve that is adjacent to the valve seat so that it can come into contact with the valve seat. The supporting member has an insulating case and a piezoelectric element housed in the insulating case, and the above-mentioned effect is achieved by applying a voltage to the piezoelectric element. The damping valve is characterized by being formed so that the damping force generated by the damping valve can be adjusted by changing the bending rigidity of the damping valve.

〔Example〕

The present invention will be explained below based on the illustrated embodiments.

FIG. 1 shows an embodiment of a hydraulic shock absorber according to the present invention, which has a piston portion 3 disposed on a piston rod 2 inserted into a cylinder 1.

Although not shown, the cylinder 1 has a connecting member such as a bracket at its lower end, so that it can be connected to the axle side of a vehicle. Further, the piston rod 2 projects from the upper end of the cylinder 1, and the projecting end of the piston rod 2 is formed so as to be connectable to the body of a vehicle.

The piston part 3 is disposed on the outer periphery of the spigot part 20 of the piston rod 2, and has an upper oil chamber A and a lower oil chamber B inside the cylinder 1.
It is divided into It is formed so as to generate a desired damping force when sliding within the cylinder 1.

In this embodiment, the piston portion 3 is formed so that a desired extension damping force is generated during the extension stroke when the piston portion 3 moves upward within the cylinder 1.

That is, the piston part 3 has an expansion side oil passage 32 and a compression side oil passage 33 in the thick part in the axial direction of the piston body 31, which has a piston ring 30 on the outer periphery that is in sliding contact with the inner peripheral surface of the cylinder 1. There is. and,
The lower end of the expansion side oil passage 32 opens into a valve seat portion 34 on the lower surface of the piston body 31, and a damping valve 35, which is a growth side valve, is arranged adjacent to the valve seat portion 34. The upper end of the pressure side oil passage 33 opens into a valve seat portion 36 on the upper surface of the piston body 31, and a check valve 37 is disposed adjacent to the valve seat portion 36. Note that the check valve 37 has a notch 37a at a portion opposite to the upper end opening of the expansion side oil passage 32, so that oil in the upper oil chamber A can flow into the expansion side oil passage 32. It is formed like this. Also, the check valve 37 is connected to the non-return spring 3.
7, and the non-returning spring 38 is locked to a stopper 39 disposed on the stepped portion 21 of the piston rod 2.

In the piston portion 3 formed as described above, the damping valve 35 is supported by the annularly formed support member 4 such that its inner end is connected to the piston body 3.
1 and the support member 4
The upper ends of the damping valve 35 are uniformly adjacent to each other, so that the outer end of the damping valve 35 is uniformly abutted against the valve seat part 34.

The support member 4 is formed to be fixed in a predetermined position by a nut 23 screwed onto the threaded end portion 22 of the piston rod 2. That is, when the nut 23 is tightened, it is brought into contact with the stepped portion 24 formed in the spigot part 20, and the support member 4 is fixed in a predetermined position by the nut 23. is fixed in a state in which it is not deformed under pressure when the nut 23 is tightened, and the adjacent damping valve 35 is brought into contact with the valve seat portion 34.

The support member 4 includes a pair of insulating cases 40 and 41 formed in a cap shape, and a piezoelectric element 42 arranged so as to be held between the insulating cases 40 and 41. It is. Further, a lead wire 43 is connected to the piezoelectric element 42, and the lead wire 43 is housed in a through hole 25 formed in the axial center of the piston rod 2, and its end Although not shown, the piston rod 2 extends outside the piston rod 2 and is connected to a suitable voltage supply source.

As mentioned above, the support member 4 is the insulating case 40,
The reason for having the piezoelectric element 42 held by the piezoelectric element 41 is that the piezoelectric element 42 causes a voltage change when pressure is applied to it. By applying the voltage, it is possible to make the piezoelectric element 42 have a stress corresponding to the voltage. That is, if the stress is reflected in the damping valve 35, the bending rigidity of the damping valve 35 is increased. This is because it becomes possible to do so.

Therefore, as a result of being formed as described above, during the extension stroke in which the piston portion 3 moves upward within the cylinder 1, the oil in the upper oil chamber A flows into the extension side oil passage 32, and the oil in the outer circumference of the damping valve 35 flows into the extension side oil passage 32. The end is bent by pressing down, and oil flows into the lower oil chamber B through the gap formed between the damping valve 35 and the valve seat part 34.

Then, when the oil flows into the lower oil chamber B,
When there is no stress in the piezoelectric element 42 of the support member 4 disposed adjacent to the damping valve 35, the rebound damping force is equal to the damping force preset by the flexural rigidity of the damping valve 35 before the change. In addition, if a voltage is applied to the piezoelectric element 42 and there is stress, the flexural rigidity of the damping valve 35 will be increased, and the damping force generated will also be increased. Become. Furthermore, when the applied voltage is changed continuously or stepwise, the flexural rigidity of the damping valve 35 changes in accordance with the voltage displacement, and the generated damping force is also changed continuously or stepwise. It will be adjusted.

FIG. 2 shows another embodiment of the invention similar to FIG. 1, in which a support member 4 and a damping valve 3 are shown.
In the form of fixation to the piston body 31 of No. 5,
This is different from the embodiment shown in FIG. Note that the same symbols used in FIG. 2 as in FIG. 1 indicate that the configuration is the same.

In another embodiment shown in FIG. 2, the damping valve 35 is fixed to the piston body 31 by a fixing member 26 prepared separately from the support member 4. This fixing member 26 is a so-called collar, and by tightening the nut 23 to the threaded portion 22 of the piston rod 2 and pressing the fixing member 26 in the direction of the piston body 31, the inner periphery of the damping valve 35 is fixed. The ends are fixed.

When the nut 23 is tightened, the upper end of the support member 4 is brought into contact with the damping valve 35 without being deformed under pressure, and due to this adjacency, the damping valve 35 is brought into contact with the valve seat 34. In this respect, there is no difference from the embodiment shown in FIG. 1.

However, among the cap-shaped insulating cases 40 and 41 arranged above and below to hold the piezoelectric element 42 constituting the support member 4, the upper insulating case 40 adjacent to the damping valve is on its adjacent side. It has a rib-like projection 40a at the upper end, and the rib-like projection 40a is connected to the damping valve 35.
It is said that it will be adjacent to.

According to the embodiment shown in FIG. 2, the damping valve 35 can be fixed to the piston body 31 more reliably than in the embodiment shown in FIG.
Since the adjoining portion between the support member 4 and the damping valve 35 is linear, there is an advantage that a stable adjoining state can be easily obtained compared to the band-like adjoining state in the embodiment shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, since the use of a solenoid is eliminated, there is no problem of a significant increase in the overall length of the hydraulic shock absorber itself or a significant increase in its diameter, which reduces its versatility. There is no advantage.

Additionally, since the use of solenoids has been eliminated, there are no significant restrictions on material selection for forming magnetic paths within the cylinder, which has the advantage of eliminating concerns about reduced durability of the hydraulic shock absorber itself or increased costs. be.

Further, since the flexural rigidity of the damping valve is changed by the supporting member adjacent to the damping valve, there is an advantage that the structure is simple and effective damping force adjustment is possible.

Furthermore, since the bending rigidity of the damping valve can be changed easily and continuously, it is possible to obtain a hydraulic shock absorber in which the damping force can be easily and continuously adjusted.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view partially showing a hydraulic shock absorber according to an embodiment of the present invention, and FIG. 2 is a longitudinal cross-sectional view showing another embodiment similar to FIG. 1. 1...Cylinder, 2...Piston rod, 3...
... Piston part, 4 ... Support member, 26 ... Fixing member, 34 ... Valve seat part, 35 ... Damping valve, 40, 41 ... Insulation case, 40a ... Rib-like projection, 42 ... Piezoelectric element, A...Upper oil chamber, B
...Lower oil chamber.

Claims (1)

[Claims] 1. A damping valve that can generate a desired damping force when a piston inside the cylinder slides, and a support member that is arranged adjacent to the damping valve so that the damping valve can come into contact with a valve seat. In addition, the support member includes a piezoelectric element housed in an insulating case, and the bending rigidity of the damping valve is changed by applying a voltage to the piezoelectric element. A damping force adjustment structure for a hydraulic shock absorber, characterized in that it is formed so as to be able to adjust the generated damping force. 2. The damping force adjustment structure for a hydraulic shock absorber according to claim 1, wherein the support member is formed in an annular shape so that it is uniformly adjacent to the damping valve. 3. The damping force adjustment structure for a hydraulic shock absorber according to claim 1, wherein the support member is formed to also serve as a fixing member to the valve seat of the damping valve. 4. The damping of the hydraulic shock absorber according to claim 1, wherein the support member has a rib-like protrusion formed on the end surface adjacent to the damping valve, and the end of the rib-like protrusion is adjacent to the damping valve. Force adjustment structure.