JPH0653835U - Hydraulic shock absorber and its sub-tank structure - Google Patents

Abstract

(57) [Summary] [Purpose] To generate damping force in a position-dependent manner even at medium and high speeds. [Structure] A valve mechanism 15 for generating a compression side damping force is arranged in a communication passage 14 of the sub-tank 11.
A fixed partition wall member 30 is provided between the movable partition wall member and the outer cylinder 18, which is a movable partition wall member. An orifice hole 31 is formed in the fixed partition wall member 30. A taper rod 32 having a base fixed to the movable partition wall member 18 is provided in the orifice hole 31. The taper rod 32 is inserted so that it can move back and forth, and the taper rod 32 is formed to have a smaller diameter toward the base.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hydraulic shock absorber used in a vehicle or the like and a sub-tank structure thereof, and more particularly to a position-dependent damping force generating mechanism and a sub-tank partition structure.

[0002]

[Prior art]

 Conventionally, as a hydraulic shock absorber used in a vehicle or the like, as described in Japanese Patent Publication No. 61-7393, a sub-tank communicating with an oil chamber in a cylinder of the hydraulic shock absorber is provided, and the inside of the sub-tank is a cylinder by a movable partition member. An oil chamber and a gas chamber that communicate with the oil chamber are defined, and a fixed partition member is provided near the inlet of the communication passage.This fixed partition member is provided with a valve mechanism that generates a compression side damping force at medium and high speeds. An orifice hole is formed in parallel with the mechanism, and a needle is inserted into the movable partition member through the orifice hole of the fixed partition member. The needle is a tapered rod that gradually becomes smaller toward the base. There is something.

[0003]

[Problems to be solved by the device]

 However, in the conventional hydraulic shock absorber described above, the fixed partition member is provided with a valve mechanism that generates a compression side damping force at medium and high speeds, and an orifice hole through which the needle is inserted is formed in parallel with this valve mechanism. Therefore, at low speed, the hydraulic oil flows into the oil chamber in the tank through the gap between the orifice hole and the needle, the movable partition member moves, and the movable partition member moves to move the needle to move between the orifice hole. The clearance changes to obtain the damping force according to the piston position.However, at medium and high speeds, the pressure side valve mechanism operates and the working oil flows directly from the pressure side valve mechanism into the oil chamber in the tank. The position-dependent characteristics due to the change in the gap between and become substantially ineffective.

In addition, the conventional sub-tank described above has a structure in which the movable partition wall member slides in the case, and thus has poor sliding stability.

[0005]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, a hydraulic shock absorber according to the present invention (claim 1) is provided with a valve mechanism for generating a compression side damping force at the time of medium and high speed between the piston and the movable partition member. A fixed partition wall member is provided between the mechanism and the movable partition wall member, an orifice hole is formed in this fixed partition wall member, and a taper rod whose base is fixed to the movable partition wall member can be moved forward and backward to the orifice hole of the fixed partition wall member. Through insertion, the taper rod was formed with a smaller diameter toward the base.

Further, in the sub-tank structure of the hydraulic shock absorber (Claim 2), a fixed inner cylinder whose inside faces the communication passage is provided in the case, and one end of the inner cylinder is closed at the outer peripheral surface thereof. An outer cylinder is slidably fitted in the inner cylinder and the outer cylinder to define an oil chamber and a gas chamber.

[0007]

[Action]

 Since the valve mechanism that generates the compression side damping force and the orifice hole of the fixed partition member are arranged in series, it is possible to generate the position dependent damping force not only at low speed but also at medium and high speeds.

In addition, a movable outer cylinder that slidably contacts the outer circumference of a fixed inner cylinder is provided in the sub-tank to define an in-tank oil chamber and a gas chamber, thereby sliding the outer cylinder serving as a movable partition member. Stability is obtained.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a partially broken sectional view of a hydraulic shock absorber to which the present invention is applied, FIG. 2 is an enlarged sectional view of a main part of a sub tank of the same shock absorber, and FIG. 3 is an enlarged sectional view of a main part of a valve mechanism part of the same sub tank. It is a figure.

A piston rod 3 is inserted into the cylinder 2 of the hydraulic shock absorber body 1 from below, and the upper end portion of the piston rod 3 is slidably contacted with the inner peripheral surface of the cylinder 2 so that two oil chambers in the cylinder are provided. A piston that defines the chamber is installed, and this piston is equipped with a valve mechanism for generating a damping force. Also, the spring seat member 4 provided at the lower end of the piston rod 3 and the outer peripheral surface of the cylinder 2 are mounted so as to be vertically movable. A suspension spring 6 is interposed between the spring seat member 5 and the sub-tank 11 on the upper end side of the cylinder 2.

The sub-tank 11 includes a connecting portion 12 that is connected to the hydraulic shock absorber body 1 and a tank case portion 13 that is integrally formed with the connecting portion 12. A communication passage 14 for communicating with the oil chamber in the cylinder is formed in the connecting portion 12, and a pressure side valve mechanism 15 for generating a compression side damping force is provided in the communication passage 14.

The lower end opening of the tank case portion 13 is closed by fitting a cap member 16, and a hollow shaft portion 13a communicating with the communication passage 14 is integrally formed at the upper end portion inside the tank case portion 13. A fixed inner cylinder 17 is screwed onto the outer peripheral portion of the hollow shaft portion 13a, and an outer cylinder 18 serving as a movable partition wall member having one end closed is slidably fitted on the outer peripheral surface of the inner cylinder 17. An in-tank oil chamber 20 communicating with the in-cylinder oil chamber through a communication passage 14 in the tank case portion 13 and a gas chamber 21 for enclosing high-pressure gas are defined.

A slide bush 22 is fitted to the outer peripheral surface of the lower end of the inner cylinder 17, a guide bush 23 is fitted to the inner peripheral surface of the upper end of the outer cylinder 18, and an air vent hole 24 is formed in the outer cylinder 18. Further, a spring seat stopper 25 is fitted on the outer peripheral surface of the upper end of the outer cylinder 18, and a spring 28 is interposed between a spring seat 26 provided on the lower surface of the spring seat 25 and a thrust washer 27 provided on the upper surface of the cap member 16. I have set up.

Then, the fixed partition wall member 30 is fixed to the inner peripheral surface of the lower end portion of the inner cylinder 17, the orifice hole 31 is formed in the fixed partition wall member 30, and the base portion is fixed to the bottom portion of the outer cylinder 18 which is the movable partition wall member. The taper rod 32 is inserted into the orifice hole 31 of the fixed partition member 30 so as to be able to move forward and backward, and the taper rod 32 is formed to have a small diameter according to the base.

Next, in the pressure side valve mechanism 15, as shown in FIG. 3, the pressure side piston 36 sandwiched between the collars 34 and 35 is fitted into the connecting portion 12, and the housing 37 is screwed into the opening portion of the connecting portion 12. Then, the collars 34 and 35 and the pressure side piston 36 are fixed, and the piston holder 38 is inserted in the pressure side piston 36.

A pressure side oil passage 40 and a pulling side oil passage 41 for medium and high speeds are formed in the pressure side piston 36, and a medium and high speed valve 42 composed of a plurality of disc valves for opening and closing the pressure side oil passage 40 is provided. A valve 43 consisting of one disc valve for opening and closing the side oil passage 41 is provided, and a low speed oil passage 44 is formed in the piston holder 38. These piston holder 38 and valves 42, 43 are provided in the piston holder 38. It is fixed to the pressure side piston 36 by a nut 45 screwed, and a valve support 46 for pressing the outer peripheral surface of the valve 42 is slidably fitted on the outer peripheral surface of the nut 45.

On the other hand, a preset adjuster 47 is rotatably fitted in the housing 37, a knob 48 is fixed to the preset adjuster 47, and a seat adjuster 50 is screwed forward and backward on the outer peripheral surface of the tip end of the preset adjuster 47. Then, the pin 51 embedded in the seat adjuster 50 is slidably fitted in the groove 37a formed in the housing 37, and the spring seat 52 provided on the front surface of the seat adjuster 50 and the rear surface of the valve support 46 described above. A spring 54 is provided between the spring seat 53 and the spring seat 53. A click mechanism 55 is provided between the flange portion 47 a of the preset adjuster 47 and the housing 37.

Further, a needle adjuster 57 is rotatably fitted in the preset adjuster 47, a click mechanism 58 is interposed between the two, and a needle holder 59 is screwed on the inner peripheral surface of the tip end of the preset adjuster 47. The needle 60 is screwed in the needle holder 59 so that the needle 60 can move back and forth, and the rear end portion 60a of the needle 60 fits in a groove 57a formed in the needle adjuster 57 and can move forward and backward. The front end portion of 0 faces the low speed oil passage 44 of the piston holder 38.

In the pressure side valve mechanism 15, when hydraulic oil flows from the in-cylinder oil chamber through the communication passage 14 in the compression stroke of the hydraulic shock absorber body 1, a gap between the needle 60 and the oil passage 44 of the piston holder 38 is generated at low speed. Through the pressure side oil passage 40 of the pressure side piston 36 to open the pressure side valve 42 at the middle and high speeds to flow into the sub tank 11 through the gap to generate a damping force. In the pulling stroke of 1, the working oil flowing from the sub-tank 11 opens the pulling side valve 43 from the pulling side oil passage 41 of the pressure side piston 36 and returns the working oil into the cylinder oil chamber through the communication passage 14.

Here, since the seat adjuster 50 is restricted from rotating by the pin 51 by rotating the knob 48 to rotate the preset adjuster 47, the seat adjuster 50 advances and retreats, so that the seat adjuster 50 moves toward the valve support 46. Since the preset load of the spring 54 changes and the pressing force of the valve support 46 on the compression side valve 42 changes, the compression side damping force at the middle and high speeds can be adjusted.

Further, since the needle 60 moves forward and backward by rotating the needle adjuster 57, the clearance between the oil passage 44 of the piston holder 38 and the needle 60 changes, and the compression side damping force at low speed changes. As described above, in the compression side valve mechanism 15, the compression side damping force generating mechanism at the middle and high speeds and the compression side damping force generating mechanism at the low speeds are arranged in parallel.

The operation of the hydraulic shock absorber and the sub-tank configured as described above will be described. When the hydraulic oil flowing from the in-cylinder oil chamber into the communication passage 14 in the compression stroke of the hydraulic shock absorber main body 1 is at a low speed, it is as described above. After the pressure side damping force is generated by the oil passage 44 and the needle 60 of the pressure side valve mechanism 15, and after the pressure side damping force is generated by the oil passage 40 and the valve 42 at medium and high speeds, the sub tank passes through the communication passage on the tank side. It flows into 11.

Then, the hydraulic oil that has flowed into the sub tank 11 flows into the tank internal oil chamber 20 inside the inner cylinder 17, and is further connected to the outer cylinder 18 through the gap between the orifice hole 31 and the taper rod 32 of the fixed partition member 30. Since it flows into the oil chamber between them, the outer cylinder 18 slides on the outer peripheral surface of the inner cylinder 17 and descends.

At this time, since the outer cylinder 18 is urged by the spring 28, the working oil in the tank internal oil chamber 20 is pressurized, so the pressure is low at the beginning of the stroke, and as the stroke proceeds, At high pressure, large cavitation occurs in the early stages to give a soft ride comfort, and as the stroke progresses, the cavitation decreases and a firm ride comfort is obtained.

Since the taper rod 32 provided on the outer cylinder 18 is formed so as to have a smaller diameter toward the base, the gap with the orifice hole 31 becomes large at the beginning of the stroke, and a soft damping force is generated. As the stroke increases, the gap decreases and the damping force increases, and the damping force according to the stroke position is obtained. Moreover, as described above, this position-dependent mechanism is installed in series with the pressure valve. Therefore, the position-dependent characteristics can be obtained not only at low speed but also at medium and high speed.

In the above embodiment, the mechanism for generating the position-dependent damping force is provided in the sub tank, but it may be provided in the hydraulic shock absorber body. In this case, a fixed partition member may be provided between the movable partition member and the piston, and a valve mechanism that generates a compression side damping force at medium and high speeds may be provided between the fixed partition member and the piston.

[0027]

As described above, according to the present invention, since the valve mechanism that generates the compression side damping force at the time of medium and high speed and the orifice hole of the fixed partition member are arranged in series, only at the time of low speed. Position-dependent damping force can be generated even at medium and high speeds. In addition, since a movable outer cylinder that slidably contacts the outer circumference of the fixed inner cylinder is provided in the sub tank to define the tank oil chamber and the gas chamber, the sliding stability of the outer cylinder, which is the movable partition member, is obtained. To be

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional view of a hydraulic shock absorber to which the present invention is applied.

FIG. 2 is an enlarged sectional view of a main part of a sub tank of the shock absorber.

FIG. 3 is an enlarged cross-sectional view of a main part of a valve mechanism portion of the sub tank.

[Explanation of symbols]

1 ... Hydraulic shock absorber main body, 2 ... Cylinder, 3 ... Piston rod, 11 ... Sub tank, 13 ... Tank case part, 14 ...
Communication passage, 15 ... Pressure side valve mechanism, 17 ... Inner cylinder, 18 ... Outer cylinder, 30 ... Fixed partition member, 31
... Orifice hole, 32 ... Tapered rod, 36 ... Piston, 42 ... Pressure side valve, 60 ... Needle.

Claims (2)

[Scope of utility model registration request] 1. A hydraulic shock absorber in which an interior of a cylinder is divided into an oil chamber and a gas chamber by a movable partition member, and a piston sliding in the oil chamber is fitted in the cylinder. A valve mechanism for generating a compression side damping force is disposed between the movable partition wall and the movable partition wall, and a fixed partition wall member is provided between the valve mechanism and the movable partition wall member. A hydraulic shock absorber, wherein a taper rod having a base fixed to a member is inserted into an orifice hole of the fixed partition member so as to be able to move forward and backward, and the taper rod is formed to have a smaller diameter toward the base. 2. A sub-tank of a hydraulic shock absorber, which is defined by an oil chamber and a gas chamber that communicate with the in-cylinder oil chamber through a communication passage by a movable partition member in the case, wherein the inside of the case is connected to the sub-tank. A fixed inner cylinder facing the passage is provided, and an outer cylinder whose one end is closed is slidably fitted on the outer peripheral surface of the inner cylinder, and the oil chamber and the gas chamber are connected by these inner cylinder and outer cylinder. The sub-tank structure of the hydraulic shock absorber, characterized in that and are defined.