JPH1038010A - Load sensitive type shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make easy loading of a load sensitive type shock absorber on a vehicle, and ensure riding comfortableness of the vehicle while the damping ratio is kept in a prescribed range when a variable control of the damping characteristics is performed. SOLUTION: The base end sides of respective valve springs 15, 16 provided on the back faces of an extension side damping valve 13 and a pressure side damping valve 14 arranged on a piston 4, are individually supported by adjusting cylinder mechanisms 23, 24, and the internal pressure of an air suspension device is introduced from outside to the adjusting cylinder mechanisms 23, 24 through a conduction passage 29 provided in a piston rod 5. As the internal pressure is changed, the adjusting cylinder mechanisms 23, 24 switch preset loads of the valve springs 15, 16 to adjust the cracking pressure of the extension side- and pressure side damping valves 13, 14, and the generated damping characteristics are variably controlled continuously or in two stages in elevation in accordance with the change in the internal pressure of the air suspension device.

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 pronounced in trucks and buses in which the sprung load changes significantly depending on the load and the number of passengers, and it is not possible to maintain optimal 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 the damping characteristics are adjusted by selecting orifices having different diameters, the damping force increases quadratically as the expansion / contraction speed increases. 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 an adjusting cylinder mechanism for supporting a base end of a valve spring provided on a back surface of a damping valve. It guides the internal pressure of the device, adjusts the cracking pressure of the damping valve while switching the set load of the valve spring with the adjusting cylinder mechanism according to the change of the internal pressure, and variably controls the generated damping characteristic according to the internal pressure change of the air suspension device. Achieved by:

A base end of a valve spring provided on the back of the damping valve is supported by an adjusting cylinder mechanism, and the internal pressure of the air suspension device is guided from the outside to the adjusting cylinder mechanism, and the internal pressure of the air suspension device is adjusted by a change in the internal pressure. This can also be achieved by switching the set load of the valve spring by the cylinder mechanism and changing the cracking pressure of the damping valve to two stages to switch the generated damping characteristics between high and low stages.

That is, with the above-described structure, in the former shock absorber, the rear surface of the damping valve is operated while operating the adjusting cylinder mechanism in accordance with the change in the internal pressure of the air suspension device, that is, the load. The set load of the valve spring provided in the is controlled to be high or low.

Further, in the latter shock absorber, a valve provided on the back surface of the damping valve is operated while operating the adjusting cylinder mechanism in accordance with the presence or absence of a load and a change in the internal pressure of the air suspension device at a predetermined load. The set load of the spring is switched between high and low.

As a result, in either case,
The cracking pressure of the damping valve changes continuously according to the load, or changes according to the presence or absence of the load or a change in the internal pressure of the air suspension device at a predetermined load.

With the change in the cracking pressure, the damping characteristic generated by the damping valve is controlled continuously or in two stages.

Accordingly, the operation amount of the adjusting cylinder mechanism is controlled based on the spring characteristics of the valve spring in accordance with the change in the internal pressure of the air suspension device, that is, the change in the spring constant due to the presence or absence of the load.

Thus, the damping characteristic (orifice characteristic) by the throttle in the low-speed region before and after the adjustment of the generation attenuation characteristic is maintained in a predetermined state, and the attenuation characteristic (valve characteristic) by the damping valve in the middle / high-speed region. ) Can be maintained in a predetermined range to provide a loaded-load-sensitive shock absorber with good riding comfort.

In addition, for the adjusting cylinder mechanism,
It is only necessary to guide the internal pressure of the air suspension device from the outside through a conduction path provided inside the shock absorber.

Therefore, no switching mechanism is required outside the shock absorber. For example, the shock absorber may be connected to the air suspension device by one or two branched pipes or the like. So
The assemblability and mountability of the shock absorber to a vehicle are also significantly improved.

[0021]

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 ends 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. .

On the other hand, the piston 4 is mutually connected to the piston rod 5 by the piston nut 9 with the guide members 7 and 8 sandwiched on both surfaces, and the piston 4
Is partitioned into an upper hydraulic oil chamber A on the piston rod 5 side 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 communicate with each other through an extension port 10 and a compression port 11 which penetrate the piston 4 and are formed obliquely. Communicates with the reservoir chamber R through a bottom orifice 12 formed in a lower portion of the cylinder 2.

Guide members 7, 8 are provided on both sides of the piston 4.
The expansion-side damping valve 13 and the compression-side damping valve 14 are attached so as to sandwich the inner peripheral portion.

The extension side damping valve 13 is pressed against the lower surface of the piston 4 by a combined force of its own flexural rigidity and the set load of the valve spring 15 interposed on the back side. The lower end opening of the port 10 is closed.

Similarly, the compression-side damping valve 14 is also pressed against the upper surface of the piston 4 by a combined force of its own flexural rigidity and the set load of the valve spring 16 interposed on the back side. Similarly, the upper end opening of the pressure side port 11 is closed.

Further, in this embodiment, the outer peripheral surface of the valve seat provided on the upper and lower surfaces of the piston 4 is stamped, and the stamping causes the expansion-side and compression-side damping valves 13 and 14 to be stamped. Restrictors 17 and 18 for generating a damping force in a low speed range are formed between the respective valve seats.

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, one end of the above-mentioned piston nut 9 is enlarged in diameter to the outer periphery to form a cylinder portion 19, and the base portion of the guide member 8 with the piston 4 interposed therebetween is connected to the cylinder portion 19. A cylinder member 20 is sandwiched and fixed opposite to the cylinder member 19.

In this embodiment, the cylinder portion 19 is formed integrally with the piston nut 9, but the cylinder portion 19 is separated from the piston nut 9 to form a separate cylinder member. Similarly to the other cylinder member 20, the guide member 7 and the piston nut 9 may be sandwiched and fixed.

The cylinder portion 19 and the cylinder member 20 are provided with piston members 21 and 22 disposed in sliding contact with the guide members 7 and 8, respectively. The cylinder portion 19 and the piston member 21 and the cylinder member 20 and the piston member The member 22 forms an extension-side adjustment cylinder mechanism 23 and a compression-side adjustment cylinder mechanism 24, respectively.

The base ends of the valve springs 15 and 16 are supported by the piston members 21 and 22, and the distal ends of the valve springs 15 and 16 are respectively supported by the extension damping valve 13 and the compression damping valve 1.
4 is in contact with the rear side through spring guides 25 and 26.

On the other hand, the piston rod 5 is connected to the adjusting cylinder mechanisms 23 and 24 from the outside and the axially
9, a lower end opening of the passage 29 is sealed with a seal member 30 interposed between the piston nut 9 and an air suspension device (not shown) through the passage 29.
Is applied to these working chambers 27 and 28.

Thus, the adjusting cylinder mechanisms 23, 2
The fourth piston members 21 and 22 are pushed in accordance with the pressure receiving area of each of the working chambers 27 and 28 at the level of the load, presence or absence, or a specific load.

In this way, the piston members 21, 22
The set load of the valve springs 15 and 16 is changed continuously or in two stages to extend and compress damping valves 13 and 14.
, And the damping characteristics on the extension side and the compression side are controlled to be high and low in accordance with the magnitude and presence / absence of the load.

In addition to the above, in the present embodiment, constant orifices 31, 32 are formed at the entrances and exits of the working chambers 27, 28, and the air suspension device is formed from the conduction path 29 through the constant orifices 31, 32. The working chambers 27 and 28 are first-order lag pressure chambers so as to guide the internal pressure.

As described above, the working chambers 27 and 28 are first-order lagging pressure chambers, even if the internal pressure of the air suspension device fluctuates due to high-frequency vibration during running of the vehicle, the fluctuations are applied to the working chambers 27 and 28. The transmission is suppressed as much as possible to prevent control instability due to frequent operation of the piston members 21 and 22.

Therefore, the above-mentioned constant orifices 31, 32 need not always be provided at the entrances and exits of the working chambers 27, 28, but are provided in a passage for guiding the internal pressure of the air suspension device to the working chambers 27, 28. It is preferable that the present invention be practiced, but it is not 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 supplied to the extension port 10 of the piston 4.
Through the throttle 17 into the lower hydraulic oil chamber B, and the flow resistance of the hydraulic oil passing through the throttle 17 generates an expansion side damping force having orifice characteristics.

On the other hand, when the expansion 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 13 is pushed open from the expansion side port 10 to open the lower hydraulic oil chamber. The hydraulic oil starts to flow to B, and the expansion resistance of the valve characteristic is generated by the flow resistance of the hydraulic oil when the expansion oil damping valve 13 is pushed open to flow.

In addition, together with these, an amount of hydraulic oil corresponding to the integral of the piston rod 5 withdrawn from the cylinder 2 is sucked from the reservoir chamber R into the lower hydraulic oil chamber B through the bottom orifice 12, 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 piston members 21 and 22 in the adjusting cylinder mechanisms 23 and 24 are used to control the change in the internal pressure of the air suspension device and the respective pressure receiving areas when the load is large or small, or when a specific load is used. , The valve springs 15 and 16 move continuously or in two steps to a position where they are balanced while expanding and contracting.

As a result, the cracking pressures of the expansion damping valve 13 and the compression damping valve 14 are switched continuously or in two stages of high and low.
Since the valve 4 does not open, the change in the cracking pressure of the compression side damping valve 14 has no effect on the generated damping characteristic during the extension stroke.

Thus, while changing the cracking pressure of the expansion damping valve 13 between high and low in accordance with the amount of load, presence or absence of the load, or a change in the internal pressure of the air suspension device at a specific load, the latter half of the low speed range is used. During·
The damping action is performed by controlling the extension-side damping characteristic by the valve characteristic over a high-speed range continuously or in two steps.

On the other hand, at the time of the reverse compression stroke, the 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 12. The hydraulic oil pressure in the lower hydraulic oil chamber B is maintained.

In the low-speed range, the hydraulic oil in the lower hydraulic oil chamber B flows from the pressure side port 11 of the piston 4 through the throttle 18 to the upper hydraulic oil chamber A, contrary to the above-described extension stroke. At the same time, the fluid flows into the upper hydraulic oil chamber A while pushing and opening the pressure side damping valve 14 in the middle / high speed range.

As a result, during the compression stroke, only the throttle 18 and the compression damping valve 14 operate compared to the previous expansion stroke, and in a low speed range, the compression resistance of the orifice characteristic is generated by the flow resistance of the throttle 18. Further, in the middle / high speed range, the pressure damping force of the valve characteristic is generated by the flow resistance of the hydraulic oil flowing by pushing and opening the pressure damping valve 14.

Also in this case, the piston members 21 and 22 of the adjusting cylinder mechanisms 23 and 24 are also provided.
The valve springs 15 and 16 can be extended or contracted continuously or two times until the balance is achieved according to the change in the internal pressure of the air suspension device and the respective pressure receiving areas at the boundary of the magnitude and presence or absence of the load or the specific load. Although the stage is switched to a stage, the expansion side damping valve 13 does not open during the compression stroke, so that there is no possibility that this will have any effect.

Therefore, even during the compression stroke, the cracking of the compression damping valve 14 is performed in accordance with the magnitude and presence or absence of the load or the change in the internal pressure of the air suspension device at the boundary of the specific load as in the case of the extension stroke. While the pressure is switched between high and low, the damping action is performed by controlling the extension side damping characteristic by the valve characteristic over the middle and high speed ranges continuously or in two steps of high and low.

In this way, in both the extension and compression strokes, the damping force of the orifice characteristics by the throttles 17 and 18 is ensured, and the valve characteristics over the middle and high speed regions are changed by the change in the internal pressure of the air suspension device. The damping characteristic is controlled to be high or low to perform the vibration damping action.

Therefore, the amount of operation of the adjusting cylinder mechanisms 23 and 24 should be set in accordance with the change in the spring constant caused by the change in the internal pressure of the air suspension device at the level of the presence or absence of the load or the specific load. Thus, while maintaining the damping ratio, which is the ratio between the spring constant and the damping coefficient, in a predetermined range, the load-sensitive shock absorber 1 with a comfortable ride while controlling the extension-side and compression-side damping characteristics in the middle and high speed regions. It becomes possible.

In the above embodiment, the case where the present invention is applied to the double-cylinder type shock absorber 1 having the bottom orifice 12 has been described. However, the present invention is not necessarily limited to this. It can be easily understood that the present invention can be similarly applied to a known single-tube type shock absorber in which a part of the cylinder 2 is partitioned as a gas chamber.

In addition, the present invention can be applied to a double-cylinder shock absorber having a base valve as described below to individually adjust the extension-side and compression-side damping characteristics. .

That is, FIG. 3 shows an embodiment in that case. In the shock absorber 1a, a valve closing the pressure side port 11 of the piston 4 is replaced with a pressure side rear valve 14b having a low cracking pressure. , Or a pressure-side check valve).

The base valve 33 is provided at the lower end of the cylinder 2 without providing an adjusting cylinder mechanism for the pressure-side rear valve 14b, and also eliminating the bottom orifice 12 provided on the lower side surface of the cylinder 2. It is arranged.

The configuration of the adjusting cylinder mechanism 23 of the extension-side damping valve 13 and the conduction path 29 for applying the internal pressure of the air suspension device to the adjusting cylinder mechanism 23 are shown in FIG. It has the same structure as the embodiment.

Accordingly, the description of these components will be omitted by assigning the same reference numerals to the same portions, and only the configuration of the base valve 33 will be described below.

The base valve 33 is formed by fitting the outer peripheral surface of the upper end of the valve case 34 to the lower end of the cylinder 2 and pressing the lower end of the cylinder 2 through the valve case 34 against the inner bottom surface of the bottom cap 6. Are centered with respect to the outer shell 3.

An extension port 10a and a compression port 11a are bored in the valve case 34 in the axial direction, and the lower hydraulic oil chamber B and the reservoir chamber R are interconnected through the extension and compression ports 10a, 11a. Is in communication with

An extension-side check valve 13a is provided on the upper surface of the valve case 34 and guided by a center pin 35. The extension-side check valve 13a is connected to the extension-side port 10a.
The upper end is closed.

Further, on the lower surface of the valve case 34, the compression side damping valve 14a and the compression side adjusting cylinder mechanism 24a are attached by clamping the inner peripheral portion by the center pin 35 with the guide member 8a interposed therebetween. The lower end of the pressure-side port 11a is closed by the damping valve 14a, and the diaphragm 18a is formed by stamping the valve seat surface.

In this case, the pressure-side adjusting cylinder mechanism 24a is different from the pressure-side adjusting cylinder mechanism in the previous embodiment in that the cylinder 20a and the piston member 22a constituting the adjusting cylinder mechanism 24a are formed by a bottom cap. It is greatly different in that it is arranged on the 6 side.

For this purpose, the valve spring 16a is
The distal end side has a spring guide 26 as in the previous embodiment.
a, the base end side is supported by a receiving plate 36 slidably fitted to the guide member 8a.

On the other hand, an adjusting cylinder 20a is formed in the bottom cap 6 so as to face the receiving plate 36, and a piston member 22a having a dish-shaped pressing portion 37 is inserted into the adjusting cylinder 20a to operate the working chamber. 28a are formed.

Then, the working chamber 28a is guided to the outside through a conduction path 29a formed in the bottom cap 6, and the internal pressure of the air suspension device is applied to the piston member 22a through the conduction path 29a.

In this way, the pressing portion 37 pushes the receiving plate 36 while pushing the piston member 22a at the boundary of the amount or presence or absence of the loaded load or a specific loaded load, and the set load of the valve spring 16a is passed through the receiving plate 37. Are controlled continuously or in two stages.

It should be noted that even in this case, the above-described conduction path 2
A constant orifice 32a is provided in the middle of 9a, and the working chamber 28a is formed as a first-order lag pressure chamber by the constant orifice 32a.

Thus, in the low speed range during the extension stroke of the shock absorber 1a shown in FIG. 3, the hydraulic oil in the upper hydraulic oil chamber A is passed from the expansion port 10 of the piston 4 through the throttle 17 to the lower hydraulic oil chamber B. And the flow resistance of the throttle 17 generates an extension side damping force having orifice characteristics.

In the latter half of the low speed range to the middle and high speed ranges, the expansion side damping valve 13 is pushed open from the expansion side port 10 to flow the hydraulic oil to the lower hydraulic oil chamber B. The extensional damping force of the valve characteristic by the flow resistance of the hydraulic oil when flowing while pushing and opening against the combined force of its own flexural rigidity and the set load of the valve spring 15 controlled by the extension side adjusting cylinder mechanism 23. Occurs.

Then, in addition to the above, the piston rod 5
An amount of hydraulic oil corresponding to the rejection volume of the lower hydraulic oil chamber B is supplied from the reservoir chamber R through the expansion port 10a of the base valve 33 to open the expansion check valve 13a, and through the throttle 18a of the compression damping valve 14a. To make up for the shortage of the hydraulic oil in the lower hydraulic oil chamber B generated by the hydraulic oil at that time.

On the other hand, during the compression stroke, the hydraulic oil in the lower hydraulic oil chamber B flows from the pressure side port 11 of the piston 4 to the upper hydraulic oil chamber A by opening the pressure side rear valve 14b. The shortage of hydraulic oil generated in the upper hydraulic oil chamber A is compensated for while maintaining the hydraulic oil pressure in the hydraulic oil chamber B at a predetermined pressure.

In addition, in the low-speed range, an amount of hydraulic oil corresponding to the volume of the penetrating piston rod 5 is supplied from the lower hydraulic oil chamber B to the throttle 18a of the base valve 33.
Through the reservoir chamber R to generate a pressure-side damping force having orifice characteristics by the flow resistance of the throttle 18a.

In the middle / high speed range, the pressure side damping valve 14a is pushed open from the pressure side port 11a of the base valve 33 to flow into the reservoir chamber R.
4a is a cylinder mechanism 2 for adjusting its own flexural rigidity and pressure side.
A pressure-side damping force of the valve characteristic is generated by the flow resistance of the hydraulic oil when the valve spring 16a is pushed open and flows against the combined force with the set load of the valve spring 16a controlled in 4a.

Therefore, the shock absorber 1 shown in FIG.
a also has a throttle 17,1 in both the extension and compression strokes, similar to the shock absorber 1 shown in FIG.
While the damping force of the orifice characteristics by 8a is ensured, the damping characteristics of the valve characteristics over the middle and high speed ranges are controlled to be high and low by the change in the internal pressure of the air suspension device to perform the vibration damping action.

From this, the amount of operation of the adjusting cylinder mechanisms 23 and 24a is set in accordance with the change in the spring constant due to the change in the internal pressure of the air suspension device at the level of the presence or absence of the load or the specific load. By doing this, the damping ratio, which is the ratio of the spring constant to the damping coefficient, is kept within a predetermined range, and while controlling the extension side and compression side damping characteristics in the middle and high speed regions, the load-sensitive shock with a good riding comfort is obtained. It can be the absorber 1a.

However, in the above-described embodiments, the air pressure, which is the internal pressure of the air suspension device, is guided to the adjusting cylinder mechanism 23, 24 or 24a to control the damping characteristics of the valve characteristics. I've been.

This means that the upper or lower hydraulic oil chamber A,
When the pressure becomes high due to the operating side of B, the adjusting cylinder mechanisms 23, 2 provided on the piston 4 for the configurational reasons.
Since the inside of the working chambers 27, 28 of 4 is air, the working chambers 27, 28 are easily compressed, and the set loads of the valve springs 15, 16 of the extension side or compression side damping valves 13, 14 become the minimum value. .

For this reason, the initial rise characteristic of the generated damping force at the time of the next reversing operation may be delayed, and the vibration absorbing effect may be insufficient to achieve the desired damping effect.

FIG. 4 and FIG. 5 show an embodiment in which measures are taken in that case. In FIG.
9, a free piston 38 is interposed in the working chamber 27,
28 and filled with oil, constant orifice 3
The working chambers 27 and 28 are prevented from being compressed by utilizing the throttle resistances 1 and 32.

Also, in FIG.
The space between the working chambers 27 and 28 is filled with oil by interposing a bellows 39 in the middle of the process, and the same effect is achieved by utilizing the throttle resistance of the constant orifices 31 and 32.

In each of the embodiments described above, the extension-side and compression-side damping valves 13, 14, or 14a are provided with adjusting cylinder mechanisms 23, 24, or 24a, respectively, so that the expansion stroke and the compression stroke can be reduced. Both damping characteristics in the middle and high speed ranges during the stroke have been controlled.

However, these adjusting cylinder mechanisms 23,
24 or 24a is connected to the extension side and compression side damping valves 13, 1
It is needless to say that the damping characteristic may be provided only in one of the first and fourth control circuits 14 and 14a to control one of the attenuation characteristics in the middle and high speed regions during the expansion stroke or the compression stroke.

[0086]

As described above, according to the first aspect of the present invention, while operating the control cylinder mechanism provided on the back side of the damping valve in accordance with the change in the internal pressure of the air suspension device due to the amount of the loaded load, By changing the set load of the valve spring and continuously variably controlling the cracking pressure of the damping valve, not only can the damping characteristic of the shock absorber be variably controlled in accordance with the amount of the loaded load, but also the spring constant of the air suspension device can be controlled. It is possible to improve the ride comfort of the vehicle by maintaining the damping ratio in a predetermined range while changing the damping coefficient according to the change.

Further, in the above, since the control cylinder mechanism and the conduction path for guiding the internal pressure of the air suspension device to the control cylinder mechanism can be provided inside the shock absorber, any switching can be provided outside the shock absorber. A mechanism is not 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, the control provided on the rear side of the damping valve at the boundary of the presence or absence of a load or a specific load while ensuring good assemblability and mountability to the vehicle. The same effect as described above can be exerted while controlling the pressure on the cylinder mechanism for use in two stages, high and low.

According to the third aspect of the present invention, the present invention is 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 type shock absorber of a base valve type,
Each of the above-described effects can be provided while finely controlling the extension side and compression side attenuation characteristics individually.

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.

Further, according to the invention of claim 6, in addition to the above-mentioned respective effects, it is possible to prevent a delay in the initial rise characteristic of the generated damping force at the time of the reversing operation, thereby exhibiting a sufficient vibration absorbing effect. Thus, it is possible to achieve a desired vibration damping action.

[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 vertical cross-sectional front view showing an enlarged main part of the same.

FIG. 3 is an enlarged longitudinal sectional front view of a main part showing an embodiment in which the present invention is applied to a base valve type double-cylinder shock absorber.

FIG. 4 is an enlarged longitudinal sectional front view of a main part showing another embodiment of a conduction path for guiding an internal pressure of an air suspension device to an adjusting cylinder mechanism.

FIG. 5 is an enlarged vertical sectional front view of a main part showing still another embodiment of the conduction path.

[Explanation of symbols]

 1, 1a Shock absorber 2 Cylinder 3 Outer shell 4 Piston 5 Piston rod 6 Bottom cap 10, 10a Extension port 11, 11a Compression port 13 Extension damping valve 13a Extension check valve 14, 14a Compression damping valve 14b Compression rear valve 15, 16, 16a Valve spring 17, 18, 18a Restrictor 19 Cylinder part of piston nut 20 Cylinder member 20a Adjustment cylinder 21, 22, 22a Adjustment piston member provided on bottom cap 23 Extension side adjustment cylinder mechanism 24, 24a Cylinder mechanism for pressure side adjustment 27, 28, 28a Working chamber 29, 29a Conduction path 31, 32, 32a Constant orifice 33 Base valve 38 Free piston 29 Bellows

Claims (6)

[Claims] 1. A base end side of a valve spring provided on a back surface of a damping valve is supported by an adjusting cylinder mechanism, and an internal pressure of an air suspension device is externally guided to the adjusting cylinder mechanism, and the internal pressure is adjusted according to a change in the internal pressure. A load-sensitive shock absorber characterized by adjusting the cracking pressure of a damping valve while switching the set load of a valve spring by a cylinder mechanism for use, and variably controlling the generated damping characteristics in accordance with changes in the internal pressure of an air suspension device. 2. A base end of a valve spring provided on a back surface of a damping valve is supported by an adjusting cylinder mechanism, and an internal pressure of an air suspension device is guided from the outside to the adjusting cylinder mechanism, and the internal pressure is changed by a change in the internal pressure. A load-sensitive shock absorber characterized in that a cylinder mechanism switches a set load of a valve spring and adjusts a cracking pressure of a damping valve to a high level and a two-step switching control of a generated damping characteristic. 3. An adjusting cylinder mechanism independently supports a base end side of each of a valve spring disposed on a back surface of an extension-side damping valve and a compression-side damping valve disposed on a piston, and
3. A load-sensitive shock absorber according to claim 1 or 2, wherein a conduction path for guiding the internal pressure of the air suspension device to each adjusting cylinder mechanism through a piston rod from outside is formed. 4. A base end side of a valve spring provided on a back side of an extension side damping valve provided on a piston and a rear side of a compression side damping valve provided on a base valve, respectively supported by an adjusting cylinder mechanism. 3. The load-sensitive shock absorber according to claim 1, wherein respective conduction paths for guiding the internal pressure of the air suspension device to the adjusting cylinder mechanism through the rod and the bottom cap are formed. 5. The shock absorber according to claim 3, wherein a constant orifice for a first-order delay is interposed in the conduction path to guide the internal pressure of the air suspension device to the adjusting cylinder mechanism. 6. The load-sensitive shock absorber according to claim 5, wherein a free piston or a bellows is interposed in the conduction path to convert the internal pressure of the air suspension device into a hydraulic pressure and to guide the hydraulic pressure to the adjusting cylinder mechanism.