JPH0227702Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a damping force adjustment structure for a hydraulic shock absorber, and in particular to a gas-filled damper that uses a piezoelectric element as an actuator of a mechanism for adjusting the damping force. The present invention relates to a damping force adjustment structure for a hydraulic shock absorber.

[Conventional technology]

For example, a hydraulic shock absorber serving as a shock absorber for a vehicle is formed to provide a uniform, predetermined damping effect depending on the characteristics of the vehicle. However, if the damping function is formed so that only a uniform predetermined damping effect is performed, the ride comfort may be improved depending on the road surface condition on which the vehicle is traveling, or
It is not possible to improve handling stability.

Therefore, in recent years, various proposals have been made for so-called damping force adjustable hydraulic shock absorbers in which the damping force generated by the hydraulic shock absorbers can be made variable in accordance with road surface conditions.

[Problem that the invention attempts to solve]

However, among the various conventional proposals described above, a damping force adjustment mechanism is provided within the hydraulic shock absorber, and an actuator for operating the damping force adjustment mechanism is attached to the outside of the hydraulic shock absorber, for example, at the upper end of the piston rod. In this case, there are disadvantages such as restrictions on the installation position when installing the hydraulic shock absorber in a vehicle, etc., and the possibility of external failures occurring in the actuator portion after installation.

Therefore, in view of the above-mentioned circumstances, the present invention is designed to be installed on vehicles without being subject to restrictions on the installation location.
Another object of the present invention is to provide a new damping force adjustment structure for a hydraulic shock absorber that can greatly reduce the risk of causing an extrinsic failure to the actuator after installation.

[Means for solving problems]

In order to solve the above problems, the structure of the present invention is
The piston rod is slidably inserted into the cylinder via the piston part, and the piston part divides the cylinder into two oil chambers. In a hydraulic shock absorber that communicates with each other via a damping force generating valve, and the damping force of the damping force generating valve is changed by the operation of an actuator, the piston part includes a piston body and a support member screwed to the piston body. It consists of
The actuator consists of a plurality of piezoelectric elements stacked in a piston rod, a damping force generating valve is supported on the upper end surface of the supporting member, a pressing member is in contact with the upper surface of the damping force generating valve, and the piezoelectric element The pressing force applied to the pressing member by applying a voltage to the damping force generating valve is transmitted to the damping force generating valve.

〔Example〕

Hereinafter, the present invention will be explained based on the illustrated embodiments.

FIG. 1 shows a hydraulic shock absorber according to a preferred embodiment of the present invention, which includes:
It is formed as a so-called gas-filled damper, and has a piston part 2 slidably disposed within the cylinder 1, and a piston rod 3 connected to the piston part 2 and having an upper end protruding outside the cylinder 1. I have it.

The interior of the cylinder 1 is divided by the piston portion 2 into a rod-side oil chamber A and a piston-side oil chamber B, which are formed so as to be able to communicate with each other via the piston portion 2. A free piston 4 is provided inside near the lower end of the cylinder 1, that is, inside the piston-side oil chamber B, and the free piston 4 defines a gas chamber C. Note that the cylinder 1 of the free piston 4
An O-ring 5 is interposed on the side sliding surface.

The piston portion 2 has a flow path 7 formed by penetrating the thick portion of the piston body 6 in the axial direction, and has a piston ring 8 on the outer periphery thereof. The upper end opening of the flow path 7 opens toward the rod side oil chamber A, and the lower end opening opens into the lower end of the piston body 6. Furthermore, a damping force generating section 9 is formed inside the lower end of the piston body 6 to generate a damping force on both sides of the expansion. It is designed so that it can be changed to

In this embodiment, the damping force generating section 9 is integrally connected to the lower end of the piston section 2.
is formed as follows.

That is, the damping force generating valves 12 on both sides of the expansion are disposed on the upper end surface of the support member 11 which is screwed into the lower end cylindrical part 10 of the piston body 6 from below. A pressing member 13 is arranged adjacent to the upper surface of the damping force generating valve 12.

The inside of the lower end cylindrical portion 10 communicates with the flow path 7 of the piston body 6. The support member 11 is formed into a cylindrical shape as a whole, and has an annular seat surface 11a formed on its upper end surface. The damping force generating valve 12 is a so-called leaf valve, and is formed into a ring shape with a notch 12a in the center. The thick lower surface of the damping force generating valve 12 is configured to abut against the annular seat surface 11a. Furthermore, the pressing member 13
is formed on its lower surface to close the center notch 12a of the rebound damping force generating valve 12 from the upper surface and to allow it to come into contact with the upper surface of the thick part of the damping force generating valve 12. It has an annular rib 13a.

Therefore, during the extension stroke in which the piston portion 2 moves upward within the cylinder 1, the oil in the rod-side oil chamber A flows into the lower end cylindrical portion 10 of the piston body 6 through the passage 7 of the piston body 6. At the same time, the oil inside the lower end cylindrical part 10 bends the inner circumferential end of the damping force generating valve 12, and the oil inside the support member 12 through the gap formed between it and the annular rib 13a of the pressing member 13.
That is, the oil flows into the piston-side oil chamber B, and at that time, a predetermined extension-side damping force is generated.

Further, during the pressure stroke in which the piston portion 2 moves downward within the cylinder 1, oil in the piston-side oil chamber B flows into the support member 12, and oil in the support member 12 flows into the damping force generating valve 12. The outer circumferential side of the rod is bent upward, and the oil flows into the lower end cylindrical portion 10 of the piston body 6 through the gap formed there, and also flows through the flow path 7 of the piston body 6 into the rod side oil chamber A. This results in an inflow into the interior. Then, when the outer peripheral end of the damping force generating valve 12 is bent and the oil flows out, a predetermined pressure side damping force is generated.

On the other hand, when the damping force generated by the damping force generating valve 12 is affected by the pressing force from the pressing member 13, the initial load of the damping force generating valve 12 is changed, so that the damping force generated by the damping force generating valve 12 is adjusted to the desired level. The damping force will be adjusted according to the size. In this embodiment, the central shaft portion 13b of the pressing member 13 is
When a pressing force from above acts on the damping force generating valve 12, the initial load of the damping force generating valve 12 is changed, and this axial pressing force is applied by the actuator according to the present invention. It is said that

That is, the piston part 2 is attached to the lower end spigot part.
An actuator 14 according to the present invention is housed inside near the lower end of the piston rod 3 where the piston rod 3 is provided. The actuator 14 includes a large number of laminated piezoelectric elements, and is configured to transmit the displacement generated when a voltage is applied to the piezoelectric elements as an axial pressing force to the pressing member 13. It is formed in The piezoelectric element serving as the actuator 14 is inserted through a through hole 3a formed in the axial center of the piston rod 3 and connected to an appropriate external power source.
When a voltage is applied to the piezoelectric element through the lead wire 16, the lower end of the actuator 14 is moved downward.

Therefore, the damping force on both sides of the expansion force generated by the damping force generating valve 12 is attenuated by transmitting the pressing force generated by applying voltage to the piezoelectric element to the pressing member 13. The initial load of the force generating valve 12 is changed, and as a result, it is possible to adjust the damping force to a desired desired damping force different from the initially predetermined damping force. Further, if the applied voltage is made variable, the pressing force by the pressing member 13 is made variable, and the initial load of the damping force generating valve 12 can be adjusted as desired.

Note that a steel ball 17 is disposed between the actuator 14 and the shaft portion 13b of the lower pressing member 13, and the piezoelectric element is damaged by the bending reaction force from the direction of the pressing member 13. It has a flexible connection structure to prevent this. In addition, the above-mentioned rod inserted into the lower end of the piston rod 3,
Although not shown, an O-ring or the like is interposed on the outer periphery of the shaft portion 13b to prevent hydraulic oil from entering the actuator portion. Furthermore, a bearing 18 is interposed inside the upper end of the cylinder 1 to ensure sliding properties of the piston rod 3, and a seal 19 is interposed to prevent leakage of hydraulic oil from inside the cylinder 1 to the outside. ing.

[Effect of idea]

As described above, the present invention has the following effects.

Since the actuator is housed within the piston rod, the structure is compact, and when installing a so-called damping force adjustable hydraulic shock absorber on a vehicle, there are fewer restrictions on the installation position. After the actuator is installed in a vehicle, external failures are less likely to occur.

Since the actuator is composed of a piezoelectric element, the damping force can be easily adjusted using only electrical operations.

The piezoelectric element has good responsiveness and generates a large pressing force despite its small size, so the pressing force is immediately transmitted to the damping force generating valve, and the initial load of the damping force adjusting valve can be quickly adjusted. , almost no electromagnetic noise.

Since the support member is screwed to the piston body, the gap between the pressing member and the damping force generation valve and the gap between the damping force generation valve and the support member can be reduced to zero when the support member is attached. It is possible to give the damping force generating valve an initial deflection according to its position.

Since the support member and the damping force generating valve are incorporated into the piston body, the length and diameter of the piston portion can be reduced.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view of a hydraulic shock absorber according to a preferred embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Cylinder, 2... Piston part, 3... Piston rod, 4... Free piston, 6... Piston body, 7... Channel, 9... Damping force generating part,
10... Lower end cylindrical part, 11... Support member, 11a
... Seat surface, 12 ... Damping force generating valve, 13 ...
Pressing member, 13a... annular rib, 14... actuator, 16... steel ball, A... rod side oil chamber, B... piston side oil chamber, C... gas chamber.

Claims (1)

[Claims for Utility Model Registration] (1) A piston rod is slidably inserted into a cylinder via a piston part, the piston part partitions two oil chambers in the cylinder, and the two oil chambers are in the piston part. In a hydraulic shock absorber that communicates with a flow path provided through a damping force generation valve provided in the flow path, and in which the damping force of the damping force generation valve is changed by the operation of an actuator, the piston portion is connected to the piston. It consists of a main body and a support member screwed into the piston body, and the actuator consists of a plurality of piezoelectric elements stacked inside the piston rod. A damping force generation valve is supported on the upper end surface of the support member, and the actuator is configured to generate a damping force. A damping of a hydraulic shock absorber, characterized in that a pressing member is brought into contact with the upper surface of the valve, and the pressing force applied to the pressing member by applying a voltage to the piezoelectric element is transmitted to the damping force generating valve. Force adjustment structure. (2) The damping force adjustment structure for a hydraulic shock absorber according to claim 1, wherein a steel ball is interposed between the actuator and the pressing member. (3) The damping force adjustment structure for a hydraulic shock absorber according to claim 1, wherein the damping force generating valve is a leaf valve having a notch in the center.