JPH1038007A - Load-sensitive shock absorber - Google Patents

Abstract

(57) [Summary] [Problem] To easily mount a load-sensitive type shock absorber on a vehicle, and at the same time, maintain the damping ratio within a predetermined range for variable control of the damping characteristic, and also secure the riding comfort as a vehicle. I do. SOLUTION: A bypass oil passage 18 provided on the upper and lower surfaces of a piston 4 to bypass a growth-side damping valve 11 and a compression-side damping valve 12, a control valve 17 for variably controlling the passage area of the bypass oil passage 18, and A conduction path 23 for guiding the internal pressure of the air suspension device to the operation surface of the control valve 17
Is installed inside the piston rod 5 and the conduction path 2
3, while controlling the control valve 17 by the internal pressure of the air suspension device applied to the operation surface of the control valve 17, the passage area of the bypass oil passage 18 is variably controlled to control the damping characteristics of the expansion damping valve 11 and the compression damping valve 12. Keep the damping ratio in a predetermined range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a load-sensitive shock absorber that automatically adjusts the damping characteristic automatically by utilizing a change in internal pressure of an air suspension device depending on the presence or absence of a load.

[0002]

2. Description of the Related Art In general, in a vehicle using an air suspension device as a suspension device, the internal pressure of the air suspension device changes depending on the amount of load (spring load) or the presence or absence of the load. Changes the spring constant.

[0003] As a result, if the damping characteristic of the shock absorber used in conjunction with the air suspension device is constant, the vibration damping performance (damping characteristic) of the shock absorber becomes excessive or insufficient depending on the amount and presence or absence of the loaded load. It will be uncomfortable.

[0004] This is particularly apparent in trucks and buses in which the load on the sprung varies remarkably depending on the load and the number of passengers, and it is not possible to maintain the optimum damping characteristics between when the vehicle is empty and when the vehicle is loaded. .

Therefore, conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 158912/1983, the diameter of the adjusting rod inserted through the piston rod is rotated from the outside together with the air suspension device to obtain the diameter. And a variable damping force type shock absorber that can adjust the damping characteristics while selecting different orifices.

A change in the internal pressure of the air suspension device due to the amount of the load is taken out as an expansion / contraction operation of the air cylinder, ie, a linear motion, and this linear motion is converted into a rotary motion by a lever to rotate the adjusting rod of the shock absorber. Thus, there has been proposed a shock absorber in which the damping characteristic of the shock absorber is adjusted in accordance with a change in the internal pressure of the air suspension device.

[0007]

However, in this method, the internal pressure of the air suspension device is taken out as a linear motion by an air cylinder, and this linear motion is converted into a rotary motion by a lever to adjust the damping characteristic of the shock absorber. Therefore, there is a problem that a large space is required for attaching them, and the mounting property is inferior.

In addition, in order to stably absorb the vibration on the spring without damaging the ride comfort of the vehicle by adjusting the damping characteristics, the spring constant of the air suspension device and the damping of the shock absorber must be adjusted. It is necessary to keep the coefficient ratio, that is, the damping ratio, as constant as possible.

On the other hand, in a shock absorber in which damping characteristics are adjusted by selecting orifices having different diameters, the damping characteristics increase in a quadratic curve with an increase in the expansion / contraction speed. In addition, while maintaining the damping ratio in a predetermined range corresponding to the change in the spring constant, it is difficult to adjust the damping characteristics of the shock absorber in accordance therewith, and the ride comfort is reduced. .

Accordingly, an object of the present invention is to provide a load capacity that can be easily mounted on a vehicle, and at the same time, can maintain the damping ratio in a predetermined range and also maintain the riding comfort of the vehicle when performing variable control of the damping characteristics. An object of the present invention is to provide a sensitive shock absorber.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shock absorber having a bypass oil passage bypassing a damping valve, a control valve offset in a direction to open the bypass oil passage, and a control valve externally provided with the control valve. A conduction path for guiding the internal pressure of the air suspension device is provided inside the shock absorber on the operation surface of the air suspension device, and the control valve is operated by changing the internal pressure of the air suspension device to continuously or simultaneously reduce the passage area of the bypass oil passage. Achieved by switching control to stages.

That is, with the above-described structure, the shock absorber allows the hydraulic oil to flow through the bypass oil passage in accordance with the expansion and contraction operation, and the damping valve in parallel with the flow of the hydraulic oil as the expansion and contraction speed increases. Push the hydraulic oil while pushing open.

In this case, the passage area of the bypass oil passage is variably controlled continuously or in two stages by a control valve which is switched in accordance with a change in the internal pressure of the air suspension device, that is, the presence or absence of the load. The orifice characteristic of the hydraulic oil flowing through the oil passage changes between high and low in accordance with the magnitude and presence or absence of the load.

In addition, the higher the orifice characteristic, the lower the expansion / contraction speed of the shock absorber when the damping valve is pushed open to flow the hydraulic oil.

From this, it is possible to adjust the damping characteristic of the orifice characteristic by the throttle in the low-speed range by switching the control valve in accordance with the change in the internal pressure of the air suspension device, that is, the change in the spring constant depending on the amount and presence or absence of the load. In addition to this, the damping characteristics of the valve characteristics by the damping valve in the middle and high speed range are adjusted while maintaining the damping ratio within a predetermined range, and a load-sensitive shock absorber that is comfortable to ride can do.

Further, in the above description, the bypass oil passage, the control valve for varying or on / off controlling the passage area of the bypass oil passage, and the conducting passage for guiding the internal pressure of the air suspension device to the operation surface of the control valve are described. In this case, the internal pressure of the air suspension device may be introduced from the outside to the operation surface of the control valve simply through the conduction path.

This eliminates the need for any switching mechanism outside the shock absorber. For example, the shock absorber may be connected to the air suspension device by one or two branched pipes. Because
The assemblability and mountability of the shock absorber to a vehicle are also significantly improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

The load-sensitive shock absorber 1 illustrated in FIG. 1 includes a cylinder 2 and an outer shell 3 arranged in an inner / outer double cylinder structure, a piston 4 slidably inserted into the cylinder 2, and The piston 4 includes a piston 4 extending from the piston 4 to the cylinder 2 and a sealing rod at the upper end of the outer shell 3 and extending outward.

The lower end portions of the cylinder 2 and the outer shell 3 are closed by bottom caps 6 welded to the outer shell 3, respectively, thereby defining a reservoir chamber R between the cylinder 2 and the outer shell 3. .

The piston 4 and the piston rod 5 are
The interior of the cylinder 2 is interconnected by the piston 4 by a piston rod 5.
And a lower hydraulic oil chamber B on the bottom cap 6 side.

The upper hydraulic oil chamber A and the lower hydraulic oil chamber B
Communicates with each other through an extension side port 8 and a compression side port 9 drilled in the axial direction with respect to the piston 4, and the lower hydraulic oil chamber B is provided with a bottom orifice 1 drilled in the cylinder 2.
0, the reservoir chamber R between the cylinder 2 and the outer shell 3
Is in communication with

On both sides of the piston 4, an extension damping valve 11 and a compression damping valve 12 are respectively mounted so as to sandwich an inner peripheral portion thereof, and the lower end of the extension port 8 of the piston 4 by the extension damping valve 11. And the compression side damping valve 12 pierces the piston 4 with the compression side port 9.
The upper end is closed.

The structure described above is a structure that has been well known in general shock absorbers, and the following structure, which will be described below, forms a structure that is particularly important in practicing the present invention.

That is, on the lower side surface of the piston rod 5, the ports 13, 1
4, and a port 14 communicates with the pressure side port 9 through an oil hole 16 formed in the piston 4 from an annular groove 15 formed in the inner peripheral surface of the piston 4.

A control valve 17 is provided inside the piston rod 5 in correspondence with the ports 13 and 14.
The control valve 17 and the ports 13 and 14, the annular groove 15, the oil hole 16 and the compression-side port 9 bypass the extension-side and compression-side damping valves 11 and 12 of the piston 4, and bypass the upper hydraulic oil chamber A.
And a lower hydraulic oil chamber B, and a bypass oil passage 18 that directly communicates with the lower hydraulic oil chamber B is formed.

The control valve 17 has an air chamber 2 between a lower end surface and a plug 19 fitted to the piston rod 5.
0, and the operating surface on the upper end side is brought into contact with the stopper member 22 by the air pressure in the air chamber 20 and the restoring force of the spring 21 provided therein.
Are offset to an upper position which keeps the passage area of the maximum.

The operation surface, which is the upper end surface of the control valve 17, is guided to the outside through an axial passage 23 formed in the piston rod 5, and the internal pressure of the air suspension device (not shown) is controlled through the passage 23. It is added to the operation surface of the valve 17.

In this manner, the control valve 17 is pushed downward while the port 13 is being pushed in accordance with the load.
To reduce the passage area of the bypass oil passage 18 as a sliding type spool valve.

In addition to the above, in the present embodiment, the constant orifice 24
Is provided, and the constant orifice 2 is
The first-order lag pressure chamber 25 is provided on the operation surface portion of the control valve 17 so as to guide the internal pressure of the air suspension device through the pressure valve 4.
Is formed.

The first-order lag pressure chamber 25 minimizes transmission of the fluctuation to the operating surface of the control valve 17 even if the internal pressure of the air suspension device fluctuates due to high-frequency vibration during running of the vehicle. This is to prevent instability of control due to frequent switching of the seventeen.

Accordingly, the above-mentioned constant orifice 24 does not necessarily need to be provided on the stopper member 22, but may be provided in a passage for guiding the internal pressure of the air suspension device to the operation surface of the control valve 17. In addition, although it is preferable for practicing the present invention, it is not always essential.

Thus, the shock absorber 1 embodying the present invention operates as follows to dampen the vibration of the vehicle.

That is, during the extension stroke in the low speed range, the hydraulic oil in the upper hydraulic oil chamber A is pushed out from the bypass oil passage 18 to the lower hydraulic oil chamber B through the control valve 17 by the piston 4, and passes through the bypass oil passage 18. An extension-side damping force with orifice characteristics is generated by the flow resistance of the hydraulic oil.

When the extension speed of the piston 4 increases and enters the middle / high speed range from the latter half of the low speed range, the expansion side damping valve 11 is also pushed open from the expansion side port 8 in addition to the above, and the lower hydraulic oil is opened. The hydraulic oil starts to flow into the chamber B, and the expansion-side damping valve 11 is pushed open to generate the expansion-side damping force of the valve characteristic by the flow resistance of the hydraulic oil flowing.

In addition, together with these, an amount of hydraulic oil corresponding to the rejected volume of the piston rod 5 from the cylinder 2 is sucked from the reservoir chamber R through the bottom orifice 10 into the lower hydraulic oil chamber B, and the hydraulic oil absorbs the hydraulic oil. The occasional shortage of hydraulic oil in the lower hydraulic oil chamber B is compensated for.

On the other hand, in this case, the control valve 17
Is switched continuously or in two stages to a position that balances the return force on the air chamber 20 side in response to changes in the internal pressure of the air suspension device due to the presence or absence of the load.

By switching the control valve 17, the degree of restriction of the port 13 is changed, and the passage area of the bypass oil passage 18 is continuously or variably controlled in two stages. If necessary, the port 13 is finally closed. Bypass oil passage 1
Block 8

In this manner, the passage area of the bypass oil passage 18 is reduced or increased or made zero according to the amount and presence or absence of the load, and the flow resistance of the working oil flowing therethrough is changed to increase the orifice characteristic in the low speed region. The side damping force is controlled to be high or low.

In addition, the higher the orifice characteristic, the lower the expansion / contraction speed of the shock absorber 1 when the hydraulic oil flows by pushing the extension side damping valve 11 open.

Thus, from the latter half of the low speed range to the middle and high speed ranges, the expansion side damping valve 11 generates the expansion side damping force of the valve characteristic having the damping coefficient controlled to be high and low, thereby performing the vibration damping action.

Conversely, during the compression stroke, an amount of hydraulic oil corresponding to the volume of the penetrating piston rod 5 is pushed out from the lower hydraulic oil chamber B to the reservoir chamber R through the bottom orifice 10. The hydraulic oil pressure in the lower hydraulic oil chamber B is maintained.

As a result, the operating oil in the lower operating oil chamber B flows from the bypass oil passage 18 to the control valve 1 in the low speed range.
7 flows into the upper hydraulic oil chamber A, and flows into the upper hydraulic oil chamber A through the pressure side port 9 by pushing and opening the compression side damping valve 12 also in the middle and high speed regions.

As a result, during the compression stroke, the compression damping valve 12 acts in place of the expansion damping valve 11 as compared with the preceding expansion stroke, and the same effect is obtained. The flow resistance of the hydraulic oil passing through the pipe generates an extension damping force having an orifice characteristic, and in the middle and high speed ranges, the compression resistance damping valve 12 is pushed open to reduce the compression damping force of the valve characteristic by the flow resistance of the hydraulic oil flowing. Occur.

In this case as well, the control valve 17 switches to a position that balances the return force on the air chamber 20 side in response to the change in the internal pressure of the air suspension device due to the presence or absence of the loading load. Bypass oil passage 18
Is continuously or variably controlled in two stages, and if necessary, the port 13 is finally closed to close the bypass oil passage 18.

Thus, even during the compression stroke, the flow resistance of the hydraulic oil passing through the bypass oil passage 18 is changed in accordance with the amount of the load and the presence or absence of the orifice in the same manner as during the expansion stroke. The compression / decompression damping force of the characteristic is controlled to be high and low, and in the middle / high speed range, the expansion side damping force of the valve characteristic having the damping coefficient controlled to be high and low by the expansion side damping valve 11 is generated to perform the vibration damping action. .

In this way, in both the extension and compression strokes, the damping characteristics of the orifice characteristics in the low speed range are adjusted by changing the internal pressure of the air suspension device.
Accordingly, the damping characteristics of the valve characteristics in the middle and high speed regions are controlled to be high and low to perform the vibration damping action.

Therefore, by setting the switching amount of the control valve 17 in accordance with the change in the spring constant caused by the change in the internal pressure of the air suspension device due to the presence or absence of the load, the ratio between the spring constant and the damping coefficient is obtained. A load-capacity-sensitive shock absorber 1 that is comfortable to ride while controlling the extension-side and compression-side damping characteristics while maintaining the damping ratio within a predetermined range.
It can be.

In the above, the case where the present invention is applied to the double-cylinder type shock absorber 1 of the bottom orifice type has been described. However, the present invention is not necessarily limited thereto, and a part of the cylinder 2 may be partially used. It can be easily understood from the above description that the present invention can be similarly applied to a known single-cylinder type shock absorber which is partitioned as a gas chamber and provided with the extension side and compression side damping valves provided on the piston.

In addition, the present invention is also applied to a shock absorber of the type having a base valve as described below, and the extension side and compression side damping characteristics are individually adjusted by the respective control valves. Further, finer control can be performed.

FIG. 2 shows an embodiment in that case. In the shock absorber 1a, the valve closing the pressure side port 9 of the piston 4 is replaced with a pressure side rear valve 12b having a low cracking pressure. , Or a pressure side check valve), and the base valve 26 is disposed at the lower end of the cylinder 2 without the bottom orifice 10.

The other parts except for the base valve 26 have the same structure as that of the embodiment shown in FIG. 1, and the same parts are denoted by the same reference numerals and their description is omitted. Hereinafter, only the configuration of the base valve 26 will be described.

The base valve 26 is formed by fitting the outer peripheral surface of the upper end of the valve case 27 to the lower end of the cylinder 2 and pressing the lower end of the cylinder 2 through the valve case 27 against the inner bottom surface of the bottom cap 6. Are centered with respect to the outer shell 3.

An extension port 28 and a compression port 29 are formed in the valve case 27 in the axial direction. The lower hydraulic oil chamber B and the reservoir chamber R are formed through the extension port 28 and the compression port 29. Communicate with each other.

An extension check valve 30 guided by a center pin 31 is provided on the upper surface of the valve case 27, and the upper end of the extension port 28 is closed by the extension check valve 30.

Further, on the lower surface of the valve case 27, the inner peripheral portion is sandwiched by the center pin 31, and the pressure-side damping valve 1 is held.
2a is attached, and the lower end of the compression side port 29 is closed by the compression side attenuation valve 12a.

On the other hand, the center pin 31 has a bypass oil passage 18a which extends in parallel with the extension-side and pressure-side ports 28, 29, and penetrates therethrough. The bypass oil passage 18a also allows the lower hydraulic oil chamber B and the reservoir chamber to be connected. R communicate with each other.

Inside the lower end of the bypass oil passage 18a,
A valve seat 32 is fitted and fixed by means of press-fitting or the like, and a poppet 33 is mounted on the bottom cap 6 so as to face the valve seat 32.
The valve seat 32 is offset in a direction to open the valve seat 32 to the maximum by a spring 34 interposed between the valve seat 32 and the center pin 31.

In this manner, the control valve 17a is constituted by the valve seat 32 and the poppet 33, and the control valve 17a is used to extend the expansion-side check valve 30 and the compression-side damping valve 1.
The passage area of the bypass oil passage 18a that directly connects the lower working oil chamber B and the reservoir chamber R while bypassing the 2a is controlled continuously or in two stages.

Then, the operation surface, which is the lower end surface of the poppet 33, is guided to the outside by a conduction path 23a formed in the bottom cap 6, and the internal pressure of the air suspension device is applied to the operation surface of the poppet 33 through the conduction path 23a. The passage area of the bypass oil passage 18a is reduced while pushing the poppet 33 in accordance with the load.

In this case, the conduction path 2
A constant orifice 24a is provided in the middle of 3a to guide the internal pressure of the air suspension device, whereby a portion of the conduction path 23a facing the operation surface of the poppet 33 is formed as a first-order lag pressure chamber 25a.

Thus, the shock absorber 1a
Also, in the low-speed range during the extension stroke, the hydraulic fluid in the upper hydraulic fluid chamber A is caused to flow from the bypass hydraulic fluid passage 18 to the lower hydraulic fluid chamber B through the control valve 17 by the piston 4, and the flow resistance of the bypass hydraulic fluid passage 18 causes the fluid to flow. Generates extension side damping force with orifice characteristics.

From the latter half of the low-speed range to the middle and high-speed ranges, the expansion-side damping valve 11 is also pushed open from the expansion-side port 8 and flows to the lower hydraulic oil chamber B. An expansion damping force of the valve characteristic is generated by the flow resistance of the hydraulic oil when the push-pull 11 is pushed open to flow.

At the same time, an amount of hydraulic oil equivalent to the integral of the piston rod 5 withdrawing from the cylinder 2 is added
While opening the extension-side check valve 30 through the extension-side port 28 of the base valve 26, and also through the bypass oil passage 18a of the center pin 31, the suction from the reservoir chamber R to the lower hydraulic oil chamber B is performed. To compensate for the shortage of hydraulic oil in the lower hydraulic oil chamber B caused by the above.

In addition, the lower hydraulic oil chamber B at this time
The operation of sucking the hydraulic oil into the oil supply is sufficient with the flow rate of the hydraulic oil supplied by opening the expansion side check valve 30 from the expansion side port 28, so that the variable control of the passage area of the bypass oil passage 18a by the control valve 17a is performed. It has no effect on the extension side damping characteristics at that time.

Therefore, the shock absorber 1a shown in FIG. 2 also reduces or increases the passage area of the bypass oil passage 18 depending on the amount of load and the presence or absence of the load, and changes the flow resistance of the hydraulic oil flowing therethrough to reduce the flow resistance in the low speed region. The extension damping force of the orifice characteristic is controlled to be high and low, and the expansion damping characteristic of the valve characteristic of the extension damping valve 11 from the latter half of the low speed range to the middle and high speed regions is also controlled to be high and low to perform the vibration damping action. .

On the other hand, during the compression stroke, the hydraulic oil in the lower hydraulic oil chamber B is caused to flow from the pressure side port 9 to the upper hydraulic oil chamber A by opening the compression side rear valve 12 b by the piston 4.
The shortage of hydraulic oil generated in the upper hydraulic oil chamber A is compensated for while maintaining the hydraulic oil pressure in the lower hydraulic oil chamber B at a predetermined pressure by the rear valve 12b.

As a result, the operation of sucking hydraulic oil into the upper hydraulic oil chamber A is also sufficient at the flow rate of hydraulic oil supplied by opening the pressure side rear valve 12b. Port 1 by 17
There is no fear that the variable control of the passage area 3 will affect the compression-side damping characteristics.

In addition, in the low-speed range, an amount of hydraulic oil equivalent to the volume of the piston rod 5 penetrating from the lower hydraulic oil chamber B is supplied from the bypass oil passage 18a in the base valve 26 to the control valve 17a. And generates a pressure-side damping force having an orifice characteristic by the flow resistance of the bypass oil passage 18a.

In the middle / high speed range, the compression damping valve 12a is also pushed open from the compression side port 29 to flow into the reservoir chamber R together with the above.
A pressure-side damping force of the valve characteristic is generated by the flow resistance of the hydraulic oil when the fluid is pushed and opened.

Therefore, even during the compression stroke, the passage area of the bypass oil passage 18a is reduced or increased depending on the amount or presence of the loaded load, and the flow resistance of the hydraulic oil flowing therethrough is changed to change the pressure side of the orifice characteristic in the low speed range. In addition to controlling the damping force to be high and low, the vibration damping action is performed while controlling the pressure-side damping force in the middle and high speed ranges to be high and low.

As described above, the shock absorber 1a in FIG. 2 also has a control valve corresponding to the change in the spring constant of the air suspension system due to the amount of load and the presence or absence of the load, similarly to the shock absorber 1 in FIG. By setting the switching amounts of 17, 17a, while appropriately controlling the damping characteristics in accordance with the magnitude and presence or absence of the load, the load-sensitive type having a comfortable ride while maintaining the damping ratio within a predetermined range. The shock absorber 1a can be used.

However, in the embodiment of FIG. 2, the control valve 17a on the base valve 26 side is
2, the poppet 33 and the spring 34 are configured as a spring offset poppet valve.
This may be configured as a spring offset type rotary valve as in the embodiment shown in FIG.

That is, in the embodiment shown in FIG. 3, a rotary control valve 17b is mounted on the bottom cap 6.
And the tip of the control valve 17b is connected to the bypass oil passage 1 of the center pin 31 of the base valve 26.
8a.

The control valve 17b has a vertical hole 35 opening at the tip and a horizontal hole 36 for guiding the vertical hole 35 to the side wall. The horizontal hole 36 has a slit 37 formed in the inner bottom of the bottom cap 6. The passage area of the bypass oil passage 18b is variably controlled by the vertical hole 35, the horizontal hole 36, and the slit 37.

On the other hand, the base end of the control valve 17b is
As shown in FIG. 5, the fan-shaped portion 38 is fitted into the fan-shaped chamber 39 of the bottom cap 6, and the spring 40 disposed in the fan-shaped chamber 39 allows the lateral hole 36 of the control valve 17 b to be maximally formed in the slit 37 on the bottom cap 6 side. It is offset so as to maintain communication with the passage area.

Then, the internal pressure of the air suspension device is guided from the outside toward the operation surface of the fan-shaped portion 38 through the constant orifice 24a and the first-order lag pressure chamber 25a by the conduction path 23a. The opening 41 is opened to the outside through the through hole 41.

As a result, the control valve 17b rotates in response to the internal pressure of the air suspension device, and accordingly,
Since the lateral hole 36 shifts in the circumferential direction with respect to the slit 37 to change the degree of communication, even in this case, the passage area of the bypass oil passage 18b is controlled while adapting to the change in the spring constant of the air suspension device. Therefore, the same operation as the embodiment of FIG. 2 can be achieved.

[0079]

As described above, according to the first aspect of the present invention, the passage area of the bypass oil passage bypassing the damping valve is variably controlled by the control valve by the change in the internal pressure of the air suspension device due to the amount of the load. Not only can the damping characteristics of the shock absorber be variably controlled in accordance with the amount of the loaded load, but also the damping ratio is kept within a predetermined range while changing the damping coefficient according to the change in the spring constant of the air suspension device. Riding comfort can be improved.

Further, in the above, since the bypass oil passage, the control valve, and the conduction path for guiding the internal pressure of the air suspension device to the operation surface of the control valve can be respectively provided inside the shock absorber, the outside of the shock absorber can be provided. No switching mechanism is required, and therefore the assemblability and mountability of the shock absorber to a vehicle can be significantly improved.

According to the second aspect of the present invention, as the internal pressure of the air suspension device changes due to the presence or absence of the loaded load, the control valve controls the passage area of the bypass oil passage bypassing the damping valve in two stages, and is equivalent to the above. The effect of can be exhibited.

According to the third aspect of the present invention, the present invention can be applied to a single-cylinder type shock absorber provided with an extension damping valve and a compression-side damping valve for a piston, or a double-cylinder shock absorber of a bottom orifice type. The above-described effects can be provided easily by implementing the present invention.

According to the fourth aspect of the present invention, the present invention is applied to a double-cylinder shock absorber of a base valve type, and the above-mentioned effects can be obtained while finely controlling the extension side and compression side damping characteristics individually. be able to.

According to the fifth aspect of the present invention, in addition to the above-described effects, when the internal pressure of the air suspension device changes at a high frequency during running of the vehicle, the control valve is frequently switched in response thereto. While preventing control instability.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing an embodiment in which the present invention is applied to a bottom orifice type double cylinder type shock absorber.

FIG. 2 is a longitudinal sectional front view showing an embodiment in which the present invention is applied to a base valve type double-cylinder shock absorber.

FIG. 3 is a vertical sectional front view showing another embodiment of the control mechanism in the base valve.

FIG. 4 is a partial plan view showing an operation portion of the control mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shock absorber 2 Cylinder 3 Outer shell 4 Piston 5 Piston rod 6 Bottom cap 11 Extension damping valve 12,12a Compression damping valve 12b Compression back valve 13,14 Port 15 Annular groove 16 Oil hole 17,17a, 17b Control valve 18,18a , 18b Bypass oil passage 20 Air chamber 21, 34, 40 Spring 22 Stopper member 23, 23a Conduction path 24, 24a Constant orifice 25, 25a Primary delay pressure chamber 26 Base valve 27 Valve case 30 Extension side check valve 32 Valve seat 33 Poppet 35 Vertical hole 36 Horizontal hole 37 Slit 38 Sector 38 Sector 39 Sector 41 Outer hole A Upper hydraulic oil chamber B Lower hydraulic oil chamber R Reservoir chamber

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhiko Yonezawa 2-4-1 Hamamatsucho, Minato-ku, Tokyo World Trade Center Building Kayaba Industry Co., Ltd. (72) Inventor Shingo Hattori 2-chome, Hamamatsucho, Minato-ku, Tokyo No. 4-1 World Trade Center Building Kayaba Industry Co., Ltd.

Claims (5)

[Claims] A bypass oil passage bypassing the damping valve;
A control valve offset in the direction in which the bypass oil passage is opened and a conduction path for guiding the internal pressure of the air suspension device from the outside to the operation surface of the control valve are provided inside the shock absorber, and the internal pressure change of the air suspension device is provided. A load-sensitive shock absorber characterized in that the control valve is operated to variably control the passage area of the bypass oil passage. 2. A bypass oil passage bypassing the damping valve;
A control valve offset in the direction in which the bypass oil passage opens and a conduction path for guiding the internal pressure of the air suspension device from the outside to the operation surface of the control valve are arranged inside the shock absorber, and the internal pressure of the air suspension device is reduced. A load-sensitive shock absorber characterized in that the control valve is operated in accordance with a change in height to control the passage area of the bypass oil passage in two stages. 3. A bypass oil passage which simultaneously bypasses the extension damping valve and the compression damping valve provided on the piston through the piston rod, and a control valve for controlling the passage area of the bypass oil passage is provided in the piston rod. 3. The load-sensitive shock absorber according to claim 1 or 2, wherein a conduction path is arranged and externally formed to guide the internal pressure of the air suspension device to the operation surface of the control valve through the piston rod from outside. 4. A bypass oil passage which bypasses an expansion damping valve provided on a piston and a compression damping valve provided on a base valve through a piston rod and a valve case is individually formed, and a passage area of the bypass oil passage is reduced. Each of the control valves to be controlled is disposed inside the piston rod and the bottom cap, and a conduction path is formed from the outside through the piston rod and the bottom cap to simultaneously guide the internal pressure of the air suspension device to the operation surfaces of these control valves. 1 or 2 payload-sensitive shock absorbers. 5. The load-sensitive shock absorber according to claim 3, wherein the internal pressure of the air suspension device is applied to the operation surface of the control valve by a conduction path through a constant orifice for a primary delay.