JPH0238112Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention relates to shock absorbers used in suspension systems of automobiles, etc., and specifically changes the damping force depending on the driving condition to improve ride comfort and handling stability. Selectable damping force adjustable shock
It is related to absorbers.

BACKGROUND TECHNOLOGY Conventionally, in a shock absorber that generates damping force by the hydraulic pressure difference between compartments in a cylinder separated by a piston, the orifice area of the passage in the piston rod that communicates the two compartments is defined as:
The damping force is made variable by controlling it with an actuator built into the piston rod. As the actuator built into the piston rod, there is one that uses a solenoid (for example, Japanese Utility Model Application No. 58-9537).

Problems to be solved by the invention A damping force adjustable shock absorber using a solenoid uses two solenoids to adjust the damping force in three or more steps. In this case, the basic configuration is to install a spool valve in the center, place separate solenoids on both sides, and switch the suction force of the solenoid by turning the power on and off.The spool valve can be placed in three or more positions in the center. There is one that is set to . This configuration requires two solenoids, which poses a problem of increased cost.

The object of this invention is to provide a damping force adjustable shock absorber that can switch the damping force in three stages using one solenoid and two spool valves.

Means for Solving the Problems and Their Effects This invention comprises: a cylinder filled with hydraulic fluid; a piston fitted externally to the end of a piston rod and slidably inserted into said cylinder; A hydraulic fluid passage that passes through the axis of the end of the piston rod and communicates both compartments in the cylinder, an on-off valve that controls the area of the hydraulic fluid passage, and an actuator that drives the on-off valve. The damping force adjustable shock absorber is provided with a hollow portion at the end of the piston rod in contact with the piston, a shaft member provided along the axis of the hollow portion, and the hydraulic fluid passageway at one end. an extension part drilled in the axial center of the shaft member; a through hole provided in the radial direction of the shaft member from both ends of the extension part; a side wall through hole provided in a side wall of the rod; the actuator is a solenoid attached to the outer periphery of the central portion of the shaft member; a spool valve that is slidably fitted onto a shaft member and has an orifice hole that communicates or blocks communication between the through hole and the side wall through hole by sliding, each of the spool valves facing the solenoid; This damping force adjustable shock absorber is characterized by having a permanent magnet on its end face and a coil spring that contacts each spool valve and biases them in the same direction.

When the polarity of the magnetic pole is switched, the spool
The valve occupies three positions, and the damping force changes in three stages accordingly.

Embodiments This invention will be described below based on drawings showing embodiments. FIG. 1 is a longitudinal cross-sectional view of the piston rod end 2 in contact with the piston 1 of the damping force adjustable shock absorber according to this invention. The cylinder is not shown. The rod end 2 is formed hollow and is fitted and fixed into an end mounting hole of the piston rod body 3. A shaft member 5 in which an extension of the hydraulic fluid passage 4 is bored is provided at the axial center of the hollow portion 2a. A solenoid 6 is attached to the outer periphery of the central portion of the shaft member 5, and magnetic poles 7a and 7b at both ends thereof are covered with a non-magnetic metal 8. A seal 9 is inserted between the non-magnetic metal 8 and the wall surface of the hollow portion 2a and between the non-magnetic metal 8 and the outer peripheral surface of the shaft member 5. Spool valves 11 and 12 are slidably inserted into the outer periphery of the shaft member 5 on both sides of the solenoid 6. Spool valve 1 facing magnetic poles 7a and 7b of solenoid 6
Permanent magnets 13 are attached to the end faces of magnets 1 and 12. Through holes 15a and 16a are provided in the radial direction from the hydraulic fluid passage 4 at both ends of the shaft member 5. Through holes 15a, 1 are provided across the space of the hollow portion 2a.
6a, a side wall through hole 15c, which passes through the piston rod end 2 and the piston rod body 3.
16c is provided. Spool valve 1
1 and 12 have through holes 15a and 16a and side wall through hole 1 at the position where the solenoid 6 is attracted.
Orifice holes 15b and 16b are provided which are coaxial with 5c and 16c, respectively. A lid 10 is fitted into the open end of the hollow portion 2a, and the end of the shaft member 5 is fixed at the center. Cylindrical wall portion 1 of lid 10
0a is inserted between the outer peripheral surface of the spool valve 12 and the inner wall surface of the hollow portion 2a, and is provided with a hole that forms part of the side wall through hole 16c of the rod end portion 2. Coil springs 17 are inserted into contact with the end faces of the spool valves 11 and 12 on the same side, respectively.

The operation of the damping force adjustable shock absorber constructed as described above will be explained with reference to FIG. In FIG. 2, the solenoid 6 is energized, and the magnetic poles 7a and 7b have the polarity to attract the permanent magnet 13. Therefore, the orifice holes 15b, 16b of the spool valves 11, 12 are connected to the shaft member 5, respectively.
The damping force is minimized because the hydraulic fluid pressure difference is minimized by aligning with the through holes 15a, 16a of the rod end 2 and the side wall through holes 15c, 16c of the rod end 2. FIG. 2 shows the state in which the solenoid 6 is de-energized, and the spool valves 11 and 12 are connected to the coil spring 17.
Only the orifice hole 15b of the spool valve 11 communicates with the through hole 15a and the side wall through hole 15c. The damping force will be of intermediate magnitude. Figure 2 and 3 show the state in which the solenoid 6 is energized so that the polarity is opposite to the case of 1.
Both spool valves 11 and 12 are repelled and separated from the magnetic poles. Through hole 15 of hydraulic fluid passage 4
a, 16a are the side wall through holes 15 of the rod end portion 2;
c and 16c. Therefore piston 1
The hydraulic fluid in the compartments on both sides of the piston 1 is communicated only through auxiliary orifices (not shown) with the smallest hole diameter provided in the piston 1, and the damping force is maximized. The auxiliary orifice may be provided in the spool valve 11 so as to communicate the through holes 15a, 16a and the side wall through holes 15c, 16c, respectively, in the state shown in FIG. 2.

Effects of the invention This invention has the structure explained above, and has one solenoid and two spools.
The effect is that a low-cost damping force adjustable shock absorber that can switch the damping force in three stages can be obtained simply by using a valve.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a main part of an embodiment of this invention, Fig. 2 1 to 3 are explanatory diagrams of the operation of the embodiment, and Fig. 3 is a partial longitudinal cross-section of a conventional general damping force adjustable shock absorber. It is a diagram. DESCRIPTION OF SYMBOLS 1... Piston, 2... Rod end, 4... Hydraulic fluid passage, 5... Shaft member, 6... Solenoid, 1
1, 12...Spool valve, 15a, 16a
...through hole, 15b, 16b...orifice hole,
15c, 16c...Side wall through hole, 17...Coil spring.

Claims (1)

[Scope of utility model registration request] A cylinder filled with hydraulic fluid and a piston
A piston that is externally fixed to the end of the rod and slidably inserted into the cylinder, and a hydraulic fluid passage that passes through the axis of the end of the piston rod and communicates both compartments in the cylinder. a damping force adjustable shock absorber comprising an on-off valve that controls the area of the hydraulic fluid passage, and an actuator that drives the on-off valve, the end of the piston rod in contact with the piston having a hollow portion; A shaft member is provided along the axis of the hollow portion, and the hydraulic fluid passage includes an extension portion bored at one end at the axis of the shaft member, and a passageway extending from both ends of the extension portion to the shaft member. The piston is coaxial with the through hole and is spaced from the through hole provided in the radial direction and the hollow portion.
It has a side wall through hole provided in the side wall of the rod,
The actuator includes a solenoid attached to the outer periphery of the central portion of the shaft member, and the on-off valve is slidably fitted onto the shaft member so as to cover the through hole on both sides of the solenoid.
A spool having an orifice hole that communicates or blocks the through hole and the side wall through hole by sliding.
A damping force comprising a valve, each spool valve having a permanent magnet on an end face facing the solenoid, and a coil spring contacting each spool valve and biasing in the same direction. Adjustable shock absorber.