JPH02286931A - Shock absorber - Google Patents

Abstract

PURPOSE:To make the expansion/contraction quantity minutely controllable by providing a displacement detection means that detects the relative variation quantity of a movable member against a fixed member. CONSTITUTION:A suspension 17 is provided with a shock absorber 1 and a coil spring 18, absorbs impulsive force given to a wheel by expansion/contraction of the spring 18, and soften the vibration transmitted to a frame. When the spring 18 expands, a piston rod 3 moved to the direction of rod expansion, and the valve 10 of first oriffice 8 is opened and oil 7 on the side of first room S1 flows into a second room S2. Expansion of the spring 18 is damped by the resistance of oil when passing through this oriffice 8, and the other valve 11 is in the state of blockade. When the spring 18 contracts, the piston 3 moved to the direction of rod contraction, the valve 10 of the oriffice 8 is closed, the valve 11 of a second orifice 9 is opened, oil 7 flows from the room S2 to the room S1, and contraction of a rod 4 is disturbed by the passage resistance of this orifice 9. The reciprocating movement of the piston 3 is fetched as electric signal of change in voltage, and controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a shock absorber used, for example, in automobile suspensions.

(Prior art) Shock absorbers conventionally used in automobile suspensions dampen the vertical movement and vibration of the vehicle body.
For example, it has an important influence on the driving characteristics and riding comfort, such as the dive and squat during acceleration and deceleration of the car, and the roll of the car body during steering.

In other words, if the damping force is too large, it will resist the action of the spring, making it possible to reduce dives and squats, but the ride will feel rough. On the other hand, if the damping force is too small, it will not be able to fully suppress the action of the springs, resulting in a large amount of dive and squat, resulting in a bouncy ride.

Therefore, shock absorbers have been proposed in which the damping force can be changed step by step between softer and harder depending on road conditions and driving conditions.

(Problem to be Solved by the Invention) However, the damping force of the above-mentioned shock absorber changes depending on its expansion/contraction speed, etc., and even if the damping force is changed stepwise as in the past, the amount of expansion/contraction of the shock absorber will vary depending on the road surface. It varied depending on the situation and driving situation. Therefore, it has not been possible to obtain a sufficient effect of reducing the amount of dive or squat when accelerating or decelerating the vehicle, or the amount of roll when steering the vehicle.

The present invention has been made to solve the problems of the prior art described above, and its purpose is as follows.

It is an object of the present invention to provide a shock absorber that can detect the amount of displacement of a movable member, and to enable fine control of the amount of expansion and contraction of the shock absorber.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a fixed member and a movable member supported so as to be movable relative to the fixed member, and the movable member absorbing the shock applied to the fixed member and the movable member by a buffer means interposed between the fixed member and the movable member;
The Tsuku absorber is characterized in that it is provided with displacement detection means for detecting a relative displacement amount of the movable member with respect to the fixed member.

(Function) The shock absorber configured as described above can detect the amount of displacement Ih of the movable member by detecting the amount of displacement of the movable member using the displacement detection means.

(Embodiment) The present invention will be explained below based on the illustrated embodiment. In FIG. It consists of a cylinder tube 2 and a piston 3 as a movable member. The piston 3 is inserted into the cylinder tube 2 so as to be able to move back and forth, and is fixed to one end of the piston rod 4. The piston rod 4 is guided through a rod guide 5 sealed at one end of the cylinder tube 2, and its rod end is fixed to an outer cylinder 6 that is slidably fitted to the outer periphery of the cylinder tube 2.

The cylinder tube 2 is a cylindrical member with one end closed.
Its open end is sealed by a rod guide 4. This cylinder tube 2 is filled with, for example, oil 7, and the piston 3 causes two chambers 31, 32.
The oil in the two chambers St and S2 is divided into two chambers St and S2, and the oil in the first chamber St and S2 is divided into two chambers St and S2. 2nd orifice 8, 9
Each orifice 8.9 is provided with a respective valve 10.11.

A differential transformer 12 is provided on the first chamber S1 side of the cylinder tube 2 as a displacement detection means for detecting the amount of displacement of the piston 3 with respect to the cylinder tube 2. The differential transformer 12 is composed of a core 13 fixed to the piston rod 4, and a primary coil 14 and secondary coils 15 and 16 attached to the inner peripheral wall surface of the cylinder tube 2.

As shown in FIGS. 4 and 5, the basic configuration and structure of the differential transformer 12 is that the secondary coils 15 and 16 are connected in series with opposite polarity to the primary coil 14, which is excited by an AC power source. The voltage induced in the secondary coils 15 and 16 by the movement of the core 13 is differentially extracted.

Namely.

If the center of the core 13 and the center of the coil 15.16 match, the voltages generated between the coils 15.16 will equally cancel each other out, so the output voltage will be O, and the core 13 will be 2.
When the secondary coils 15, 16 are shifted to either side, a difference occurs in the voltage induced in each coil 15, 16, and this potential difference is extracted.

The differential transformer 12 is non-contact, has a simple structure, has excellent linearity and high resolution, and generally has a detection range of ±
Since it has a wide range of 0.05 to ±200 mm, the amount of displacement of the piston 3 can be easily detected.

FIG. 3 shows an example of an automobile suspension to which the shock absorber of the present invention is applied. That is,
This suspension 17 is
and a coil spring 18, which absorbs the impact force applied to the wheel by the expansion and contraction of the coil spring 1B, and alleviates the vibration transmitted to the frame.The vibration of the coil spring 18 is damped by the shock absorber l. It has become. When the coil spring 18 extends, the piston 3 moves in the rod extension direction as shown in FIG. 1, the valve 10 of the first orifice 8 opens, and the oil 7 on the first chamber S1 side flows into the second chamber S2. flows into. The expansion of the coil spring 18 is attenuated by the flow path resistance of the oil when it passes through the orifice 8. At this time, the other valve 11 is in a closed state.

On the other hand, when the coil spring 18 contracts, the piston 3 moves in the rod contraction direction as shown in FIG. 2, the valve 10 of the first orifice 8 closes and the valve 11 of the second orifice 9 opens, causing 7 flows into the first chamber S1 from the second chamber S2. This flow path resistance of the second orifice 9 prevents the rod 4 from contracting.

Here, along with the reciprocating movement of the piston 3, the core 13 fixed to the piston rod 4 moves in the axial direction, and the secondary coil 1
A voltage is induced at 5.16, and the amount of displacement can be extracted as an electrical signal of voltage change.

If the amount of displacement of the piston 3 can be directly detected in this way, the moving speed and damping force of the piston 3 can be calculated by a microcomputer, and the damping force can be precisely controlled according to road surface conditions and driving conditions. becomes possible.

In the above embodiment, the differential transformer 12 is placed inside the cylinder tube 2, but the differential transformer 12 may be placed outside the cylinder tube 2 as shown in FIG.
That is, a transformer rod 19 is attached parallel to the piston rod 4 to the outer cylinder 6 to which the piston rod 4 is fixed, and the core 13 is fixed to the tip of this rod 19.

On the other hand, the above-mentioned transformer rod 1 is attached to the cylinder tube 2.
A coil housing section 20 is attached to which the cores 13 of 9 can be freely retracted and retracted, and primary and secondary coils 14, 15, and 16 are housed in the inner periphery of this coil housing section 20. A rod 19 is attached to the outer cylinder 6 as the piston 3 reciprocates.
reciprocates, the core 13 moves and the secondary coil 15.16
A voltage is induced in

Further, the displacement detecting means is not limited to the differential transformer 12 described above, but a potentiometer 21 as shown in FIG. 7 may be used.

The button yometer 21 is configured such that, for example, a linearly sliding resistance track 22 is provided on the piston rod 4 along its axial direction, and a slider 23 that slidably contacts the resistance track 22 is fixed to the cylinder tube 2. configured. Then, the amount of displacement of the piston 3 is converted into electrical resistance between a terminal 24 connected to one end of the resistance track 22 and a terminal 25 connected to the slider 23 and extracted.

If such a potentiometer 21 is used, a highly accurate and relatively large analog output can be obtained, and since it can be easily linked with a mechanical quantity, displacement of the suspension can be easily detected.

Regarding the mounting location of this potentiometer 21, the sixth
It may be installed on the outside of the cylinder tube 2 like the differential transformer shown in the figure, or it may be installed on the sliding part between the outer cylinder 6 and the cylinder tube 2, in other words, between the piston 3 and the cylinder. Any position may be used as long as the relative displacement with the tube 2 can be converted into a change in electrical resistance.

In addition to the above-mentioned differential transformer and potentiometer J meter, various means such as a Tftft upper type sensor and electric sensor can be used as the displacement detecting means.

Furthermore, in the above embodiment, the basic structure of a shock absorber is shown in which the cylinder tube is filled with oil and the flow path resistance of the orifice provided in the piston is used. However, the present invention is not limited to this. There are twin-tube types with a reservoir chamber between the inner and outer cylinders, and so-called seven-tube types with a free piston under the piston of a single cylinder tube, which is filled with high-pressure gas.
It can be applied to various types of shock absorbers such as tube type shock absorbers.

Further, in this example, a case has been described in which the shock absorber is used as a damper for an automobile suspension, but the present invention can be widely applied to various control devices in which the shock absorber is used.

(Effects of the Invention) The present invention has the above-described configuration and operation, and since the displacement of the movable member is detected by the displacement detection means, it is possible to detect the amount of movement of the movable member when an impact is applied. This makes it possible to finely control the damping force of the shock absorber depending on the impact.

[Brief explanation of the drawing]

1 and 2 show a shock absorber according to an embodiment of the present invention, in which FIG. 1 is a longitudinal cross-sectional view showing an extended state, FIG. 2 is a longitudinal cross-sectional view of a contracted state, and FIG. Fig. 1 is a schematic front view showing an example of a car suspension to which the shock absorber is applied, Fig. 4 is a circuit diagram showing the basic configuration of the differential transformer shown in Fig. 1, and Fig. 5 is a differential transformer. FIG. 6 is a longitudinal sectional view of a shock absorber with the differential transformer shown in FIG. 1 provided outside, and FIG. 7 is a longitudinal sectional view of a shock absorber according to another embodiment of the present invention. be. Explanation of symbols 1... Shock absorber 2... Cylinder tube (fixed member) 3... Piston (movable member) 4... Piston rod 7... Oil 8.9...
1st. Second oriice (M impact means) 10.11...Valve 12...Differential transformer (displacement detection means) 13...Primary coil 14.15...Secondary coil 17...Suspension 18 ...Coil spring 19...Transformer rod 2
0... Coil storage section 21... Potentiometer (displacement detection means) 22...
・Resistance track 23...Slider Figure 4

Claims (1)

[Scope of Claims] It has a fixed member and a movable member supported so as to be movable relative to the fixed member, and a shock applied to the movable member is absorbed by a buffer means interposed between the fixed member and the movable member. A shock absorber comprising: displacement detection means for detecting a relative displacement amount of the movable member with respect to the fixed member.