JPS61290249A - Oil hydraulic shock absorber - Google Patents

Abstract

PURPOSE:To obtain an oil hydraulic shock absorber equipped with an anti roll function, by providing a selector valve, which switches a passage in a base valve part to be opened and closed, while connecting an upper chamber in a cylinder with an external accumulator when the selector valve is closed. CONSTITUTION:A shock absorber provides a selector valve 31, which switches a passage (a) to be opened and closed by a supply pressure P from the outside, to be arranged in the passage (a) in a base valve part 30 while a passage (b), through which an upper chamber a in a cylinder 10 communicates with an accumulator 50 in the outside when the selector valve 31 is closed, in a piston rod 21. Consequently, the shock absorber, placing inside the upper chamber A in the cylinder under an extension side oil lock condition according to repulsive force in the accumulator 50 by controlling the selector valve 31 to be shut off, enables a roll phenomenon in a vehicle to be effectively suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic shock absorber, and more particularly to a hydraulic shock absorber capable of exhibiting an anti-roll function and capable of controlling the attitude of a vehicle.

[Conventional technology]

2. Description of the Related Art It is well known that a vehicle is equipped with an attitude control device in order to improve the running stability of the vehicle, and various attitude control devices have been proposed in the past. In order to prevent the roll phenomenon in which the outside of the vehicle sinks significantly when the vehicle makes a sharp turn, these conventional attitude control devices generate a large reaction force on the vehicle height adjuster that is subjected to the sinking effect. It has been proposed as an anti-roll function.

For example, an attitude control device as shown in Figure 5 has been proposed. The attitude control device according to this proposal has a pair of left and right vehicle height adjusters 1.1, and an upper chamber A defined by a piston portion 3 in a cylinder 2 constituting each vehicle height adjuster 1. It has a lower chamber B, and one upper chamber A communicates with the other lower chamber B, and one lower chamber B communicates with the other upper chamber A through passages H, H, respectively, in a so-called swivel shape. It is something that and,
Each cylinder 2 has a gas chamber G at its upper end, and each vehicle height adjuster 1 has its upper end connected to the main body side and its lower end connected to the axle side.

As a result, for example, when the left and right vehicle height adjusters 1°1 contract in the same phase, each upper chamber A compresses the gas chamber G by the volume of entry of the piston rod 4. At this time, the gas chamber G is compressed by the amount of the intrusion volume of the piston rod 4, so the reaction force generated on each piston rod 4 is small, and the ride comfort is reduced during normal driving of the vehicle. It won't make things worse.

On the other hand, when the left and right vehicle height adjusters 1, 1 expand and contract in opposite phases, that is, when the vehicle makes a sharp turn and a roll phenomenon occurs, for example, the right vehicle height adjuster 1 in the figure When the left vehicle height adjuster 1 contracts and extends, the right upper chamber A
In addition to its own compression, it also receives hydraulic pressure from the left lower chamber B, and at this time, the right gas chamber G receives an extremely large pressure. Can generate a large reaction force,
This provides an anti-roll function that prevents the vehicle from rolling, resulting in improved vehicle running stability.

[Problem that the invention seeks to solve]

However, when using the above conventional example, the passages H and H must be formed in a so-called sash shape, which has the disadvantage that installation space is easily constrained when installing it on a vehicle. The attitude control system in this example is installed on a vehicle solely for the purpose of demonstrating the anti-roll function, so a shock absorber to improve vehicle ride comfort must be installed separately on the vehicle. First, the number of parts increases and the installation space is also restricted.

Since the upper chamber A and the lower chamber B in each vehicle height adjuster 1 are formed independently of each other, if oil leaks from the piston portion 3 or to the outside of the cylinder 2, the upper chamber A and the lower chamber B are formed independently of each other. This will cause a change in the amount of oil in A and the lower chamber B or a change in the volume in the gas chamber G, and as a result, there is a risk that the characteristics of the repulsion force will change.

Furthermore, when even a slight roll phenomenon occurs, that is, an opposite phase occurs, the gas chamber G is made smaller in order to generate a large reaction force, so a large reaction force is likely to occur even when the phases are the same. There are also inconveniences such as deterioration of the ride comfort of the vehicle and deterioration of the durability of the gas chamber G and the like.

Furthermore, in vehicles such as double-decker buses, which have a high center of gravity and are at high risk of overturning due to roll phenomena, the so-called oil lock state may be set to the extension side in order to exhibit a more effective anti-roll function. It is preferable and necessary to have a relief effect, but in the conventional proposal mentioned above, it is not possible to achieve an oil lock state on the extension side, and also,
There is an inconvenience that a relief effect cannot be exerted.

[Purpose of the invention]

Therefore, in view of the above-mentioned circumstances, the present invention is convenient for mounting on a vehicle without being limited by the installation space, is economical due to the small number of parts, and furthermore, does not cause changes in repulsion force characteristics. We offer a new hydraulic shock absorber that not only provides a desirable anti-roll function to control the vehicle's attitude, but also provides a damping function as a shock absorber to improve the ride comfort and handling stability of the vehicle. The purpose is to

[Means for solving problems]

In order to solve the above-mentioned problems, the structure of the present invention has a passage outside the cylinder that allows communication between an upper chamber and a lower chamber defined by a piston part inside the cylinder, and
A hydraulic shock absorber including a damping valve in the passage in the base valve section in the lower part of the cylinder,
A switching valve is disposed in the passage in the base valve section to enable the passage to be opened and closed by supply pressure from the outside, and the damping valve is configured to enable generation of damping force on both sides of expansion. Firstly, when the switching valve is closed, the upper chamber in the cylinder is communicated with an external accumulator, and the oil in the upper chamber in the cylinder can leak into the lower chamber in the cylinder. Oni is characterized by being formed,
When the switching valve is closed, the upper chamber in the cylinder is communicated with the external accumulator, and the lower chamber in the cylinder is in an oil lock state.Furthermore, when the switching valve is closed, the oil in the upper chamber in the cylinder is transferred to the lower chamber in the cylinder. It is characterized by being formed so as to allow relief to the chamber and relief of oil in the lower chamber in the cylinder to the reservoir chamber.

〔Example〕

The present invention will be explained below based on the illustrated embodiments.

,! Figure 1 is an embodiment showing the principle of the hydraulic shock absorber according to the present invention, and the same applies to the cases shown in Figures 2 to 4 below. They are arranged independently in each part.

As shown in FIG. 1, the hydraulic shock absorber according to the present invention has an upper chamber A and a lower chamber B partitioned by a piston part 20 inside the cylinder 10, and a reservoir chamber C outside the cylinder 10. It has a passage α. The cylinder 10 has a base valve section 30 in its lower part. Note that the upper end of this device is connected to the vehicle body side of the vehicle, and the lower end is connected to the axle side of the vehicle.

An outer cylinder 11 and an inner cylinder 12 are disposed outside the cylinder 10, the passage α is formed between the cylinder 10 and the inner cylinder 12, and the outer cylinder 11 and the inner cylinder 1
2 is the reservoir chamber C. A bearing member 13 is disposed at the upper ends of the cylinder 10, the outer cylinder 11, and the inner cylinder 12, and closes the upper ends of the cylinder 10, the outer cylinder 11, and the inner cylinder 12.

Note that the base valve section 30 closes the lower end sides of the cylinder 10, the outer cylinder 11, and the inner cylinder 12.

The passage α communicates with the upper chamber A in the cylinder through a through hole 1°4 formed at the upper end of the cylinder 10 on the one hand, and communicates with the upper chamber A in the cylinder through the base valve portion 30 on the other hand. It communicates with room B.

The piston portion 20 includes a piston body 22 attached to the lower end of a piston rod 21 that passes through the bearing member 13 and is inserted into the cylinder 10 . The piston part 20 prevents the oil in the cylinder upper chamber A from flowing into the cylinder lower chamber B through the piston part 20 during the extension stroke when the piston main body 22 moves up inside the cylinder 10. and a relief valve 24 that allows oil in the upper cylinder chamber A to leak into the lower cylinder chamber B via the piston portion 20.

A passage is formed in the piston rod 21, and the lower end of the passage communicates with the relief valve 24 and the upper chamber A in the cylinder, and the upper end of the passage communicates with the piston rod 21. It exits from the vicinity of the upper end and communicates with an accumulator 50 disposed outside.

The base valve section 30 is provided with a damping valve 4o and a switching valve 31.

The damping valve 40 and the switching valve 31 are located in a passage α positioned in a portion of the base valve portion 30 in the passage α that allows communication between the cylinder internal upper chamber A and the cylinder internal lower chamber B. When the switching valve 31 is switched to the cutoff state due to the action of the supply pressure P consisting of hydraulic pressure or pneumatic pressure from the outside via the supply passage 32, the passage α is closed. The passage α is formed so that the flow of oil is blocked, and when the action of the supply pressure P is released, it is switched to the communication state, and the passage α is formed so that the oil can flow through the passage α. ing. The damping valve 40 generates a desired damping force on both sides of the expansion pressure when oil flows through the passage α.

In addition, in this embodiment, the damping valve 40 is -
It has a throttle valve 41 and another throttle valve 42, and the - throttle valve 41 is used when oil flows in the passage α in the direction from the upper cylinder chamber A to the lower cylinder chamber B. The other throttle valve 42 is formed so as to be able to generate a damping force when oil flows in the direction from the lower chamber in the cylinder to the passage α.

The passage a in the base valve section 30 communicates with the reservoir chamber C and also with a check valve 43 that is parallel to the other throttle valve 42 . Note that the check valve 43 is formed to allow oil to flow from the passage a to the cylinder inner lower chamber B, and to prevent the oil from flowing backward.

The accumulator 50 has a free piston 51 inside.
It also has a gas chamber 52 and an oil chamber 53 defined by the free piston 51, and the oil chamber 53 communicates with the upper chamber A in the cylinder via the passage. be. And the above accumulator 5
0, the gas pressure in the gas chamber 52 is set to a predetermined value, and the oil in the upper chamber A in the cylinder is in the oil chamber 53.
In other words, when the switching valve 3
1 is in a cutoff state, the gas chamber 52 is compressed as the free piston 51 moves, and air pressure is generated in the gas chamber 52 to prevent oil from flowing out in the upper chamber A of the cylinder, The accumulator 50 is formed so that the extension side oil lock state of the present hydraulic shock absorber is exerted. In addition, the above accumulator 5
A throttle h is arranged in the passage communicating with 0,
Care is taken to prevent the oil that has flowed into the oil chamber 53 from flowing out suddenly when it returns to the passage.

The operation of the hydraulic shock absorber according to the present invention formed as described above will be briefly explained.

First, when functioning as a normal shock absorber, the external supply pressure P acting on the switching valve 31 is released and the passage a is placed in a communicating state as shown in the figure.

Then, during the extension stroke in which the piston portion 20 ascends within the cylinder 10, the oil in the upper chamber A- in the cylinder is drained through the through hole 14,
Passage α, - switching valve 31. - flows into the cylinder inner lower chamber B via the throttle valve 41 and check valve 43, and oil corresponding to the amount of withdrawal of the piston rod 21 flows from the reservoir chamber C to the inner cylinder lower chamber B via the passage α and the check valve 43. Flows into room B. At this time, a desired expansion-side damping force is generated by the throttle valve 41 of the damping valve 40.

Next, during the pressure side stroke in which the piston part 20 descends within the cylinder 10, the oil in the lower chamber B in the cylinder flows into the upper chamber A in the cylinder, and at the same time, the oil in the cylinder inner chamber A flows into the passage α, the switching valve 31, and the throttle valve 41 into the reservoir chamber C and, on the other hand, through another throttle valve 42 into the reservoir chamber C. At this time, a desired compression side damping force is generated by the throttle valves 41 and 42, which are the damping valve 40.

During either the expansion side or compression side stroke, the oil in the cylinder upper chamber A does not flow out to the accumulator 50 side through the passage in the piston rod 21.

In addition, when this device is greatly compressed due to the roll phenomenon of the vehicle, etc., and when it is decided to perform the anti-roll function and prevent the large compression, the external A predetermined supply pressure P is supplied to the switching valve 3 through the pressure supply passage 32, and the switching valve 31 is switched to the cutoff state to close the communication in the passage α.

By the shutoff operation of the switching valve 31, the passage a in the base valve portion 30 is closed, and therefore, the oil in the upper cylinder chamber A is prevented from flowing into the lower cylinder chamber B, but the piston rod 21 The oil flows into the oil chamber 53 in the accumulator 50 through the passageway and the restriction b. When oil flows into the oil chamber 53 from the upper chamber A in the cylinder, the free piston 51 moves and compresses the gas chamber 52. The reaction force at this time puts the inside of the cylinder upper chamber A into an oil lock state, that is, the extension side oil lock state occurs during the extension stroke when the piston portion 20 moves up inside the cylinder 10.

Note that the excessive load in the upper cylinder chamber A, that is, the excessive load on the expansion side, is released by opening the relief valve 24 provided in the piston body 22.

FIG. 2 shows the principle of a hydraulic shock absorber according to another embodiment of the present invention in the same way as in FIG. The only difference is in the configuration, and the other configurations are the same as in FIG. 1.

That is, the relief valve 44 is connected to the lower chamber B in the cylinder.
This device is designed to release the overload on the pressure side, that is, the overload on the pressure side.As a result of installing the relief valve 44 in place of the throttle valve 42, this device has the following features: In addition to the extension side oil lock state, the compression side oil lock state can also be obtained.

In the operation of the embodiment shown in FIG.
1. The oil in the cylinder lower chamber B passes through the damping valve 40 and flows into the cylinder lower chamber B during the pressure side process. The oil flows into the upper chamber A and passes through the passage α, the switching valve 31, and the damping valve 40, resulting in a different flow of oil from that in the embodiment shown in FIG.

As a result, when this device operates as a shock absorber, the damping force in both the expansion side and the compression side is generated by the throttle valve 41, which is the damping valve 40, and when the oil is locked, the damping force is generated in the upper part of the cylinder. Both the expansion side, which is the side of the chamber A, and the compression side, which is the side of the lower chamber B in the cylinder, are in an oil lock state, and in this embodiment, the oil lock state is realized on both expansion and compression sides.

In addition, when the oil is in the above-mentioned oil lock state and an excessive load is caused in the upper cylinder chamber A and the lower cylinder chamber B, the respective relief valves 24 and 44 are activated to remove the overload. will be cancelled.

Figure 3 shows an embodiment of the embodiment shown in Fig. 1, and Figure 4 shows an embodiment of the embodiment shown in Fig. 2.

The embodiment shown in Fig. 3 and Fig. 4 will be briefly explained.

As shown in Figures 3 and 4, the hydraulic shock absorber according to this embodiment has a piston part 20 in a cylinder 10, and a base valve part 30 in a lower part of the cylinder 10.

Outside the cylinder IO, an outer cylinder 11 and an inner cylinder 12 are provided.
The inside of the cylinder 10 is divided into an upper chamber A and a lower chamber B by the piston part 20. A passage a is formed between the cylinder 10 and the inner cylinder 12, and a reservoir chamber C is formed between the inner cylinder 12 and the outer cylinder 11. Further, a bearing member 13 is disposed at the upper ends of the cylinder 10, outer cylinder 11, and inner cylinder 12, and closes the upper ends of the cylinder 10, outer cylinder 11, and inner cylinder 12.

Note that the lower end sides of the cylinder 10, outer cylinder 11, and inner cylinder 12 are arranged so that the base valve part 3o is in contact with the cylinder 10 and the inner cylinder 12, and the lower end bracket 15 is attached to the outer cylinder 11. They are each formed to be closed when brought into contact with each other.

Furthermore, in place of the through hole 14 in the embodiment shown in FIGS. 1 and 2, a notch 13α is formed in the bearing member 13, so that the upper chamber A in the cylinder communicates with the passage α. Above the bearing member 13 and inside the upper end of the outer cylinder 11, a packing case 16 housing an oil seal 16α is screwed.

The piston part 20 has a piston body 22 fixed to a part of the lower end pilot of the piston rod 21 which is inserted through the center part of the bearing member 13, and the inside of the cylinder 10 is connected to the upper chamber A by the piston body 22. Lower chamber B
It is divided into The piston body 22 is formed with an oil passage 22α that is perforated in the axial direction.
The upper chamber A and the lower chamber B are formed to communicate with each other via the oil passage 22α. Furthermore, a check valve 23 consisting of a leaf valve is disposed at the mouth end of the upper chamber A side of the oil passage 22α, and the oil on the lower chamber B side flows through the oil passage 22α, and the check valve 23 It is formed so that it opens and flows into the upper chamber A, and the opposite flow is blocked.

A passage is formed in the axial center of the piston rod 21, which communicates the upper chamber A in the cylinder with the accumulator 50 outside the hydraulic shock absorber, and the lower end of the passage is located near the lower end of the piston rod 21. The passage opens into the upper chamber A within the cylinder, and the upper end of the passage opens into an upper end bracket 25 screwed onto the upper end of the piston rod 21. The passageway is connected to the upper end bracket 25.
The external accumulator 5
Connected to 0.

That is, the upper cylinder chamber A is formed so as to communicate with the external accumulator 50 via the passage within the piston rod 21.

A relief valve 24 is disposed within a portion of the lower end pilot of the piston rod 21 constituting the piston portion 20 . That is, a passage 24α that allows communication with the passage 6 is formed inside a part of the lower end of the piston rod 21, and the relief valve 24 closes the passage 24α from the lower chamber B side. The disposed steel ball 24b, the spring 24C that urges the steel ball 24b in the closing direction, and the -spring 24
A stopper 24d is press-fitted into the oil passage 24a to lock the rear end of the steel ball 24b against the repulsive force of the spring 24C when the oil pressure in the upper chamber A becomes excessive. The oil in the upper chamber A is caused to flow out into the lower chamber B by moving the oil in the upper chamber A to the lower chamber B.

The piston body 22 is fixed by a nut 26 screwed onto the lower end of the piston rod 21, and the check valve 23 is energized by a non-return spring 23α, which is connected to a valve stopper. 23hK is locked. Further, a cap 27 is fixed to the upper end of the piston rod 21, and a cover 27α is vertically provided on the cap 27.

The base valve section 30 has a switching valve 31 inside,
and a damping valve 40.

The switching valve 31 is supported from below by the bracket 15 and is shaped like a poppet valve so as to be housed in a valve housing 33 disposed to be fitted inside the lower end of the inner cylinder 12. It has a poppet 31α. The poppet 31α is urged downward by a spring 31b from above, and a free piston 31C is brought into contact with the lower end of the poppet 31α from below.

The free piston 31C is slidably housed in a back pressure chamber 31d that communicates with a supply path 32 for the external supply pressure P formed in the bracket 15, and supplies the external supply pressure P. , the poppet 31α is pushed against the valve housing 3 against the repulsive force of the spring 31h.
It is formed to rise within 3. The poppet 31α is held in sliding contact with a bush 31g disposed within the valve housing 33.

The valve housing 33 that accommodates the switching valve 31 made of the poppet valve includes a passage 33α that communicates between the passage α formed between the cylinder 10 and the inner cylinder 12 and the switching valve 31; A passage 33b and a notch 33c are formed to communicate the reservoir chamber formed between the outer cylinder 11 and the inner cylinder 12 and the upper end side of the valve housing 33, that is, the lower chamber B side. When the poppet 31α rises to close the opening of the passage 33a, the oil is prevented from flowing out from the passage α.

The damping valve 40 is formed in the form of a plate valve, and in the embodiment shown in FIG.
and another damping valve 42.

That is, the valve housing 33 has a valve disc 34 disposed on the outer peripheral side of the upper end thereof and the lower end of the cylinder IO, and a lower end thereof is located in the center of the valve disc 34. It has a rod seat 35 supported at the center of the upper end. The - damping valve 41 includes a leaf valve 41α that is bored in the rod seat 35 and closes the upper end opening of the oil passage 35α that allows communication between the front side of the poppet 31α and the lower chamber B side; It consists of a plate valve 41j that abuts from the back side (upper surface in the figure) of the leaf valve 41α, and a spring 41C that biases the plate valves 41, 6 from above to below, and the lower chamber is connected to the poppet 31α from the front side of the poppet 31α. It is opened when oil toward the B side flows through the oil passage 35α, and is formed so as to generate a predetermined damping force.

On the other hand, the other damping valve 42 is
an inner oil passage 34α that is bored in the inner thick part of 4 and enables communication between the lower chamber B side and the front side of the poppet 31α;
A leaf valve 42α that closes the lower end opening of the leaf valve 42α, a plate valve 426 that comes into contact with the leaf valve 42α from the back side (bottom surface in the figure), and the spring 41C that biases the plate valve 42h from below to above. The oil flowing from the lower chamber B side to the front side of the poppet 31α flows through the inner oil passage 34.
It is formed to generate a predetermined damping force when flowing through α.

In addition to the inner oil passage 34α, an outer oil passage 345 is formed in the valve disc 34.
A check valve 43 is arranged to close the upper end opening of 4b. The check valve 43 is energized by a non-return spring 43a, and the non-return spring 43α is stopped by a valve stopper 43A. A notch 43 facing the upper end opening of the inner oil passage 34 (Z) is formed on the inner peripheral side of the check valve 43.

The filter plate valve 41J of the - damping valve 41 and the plate valve 42b of the other damping valve 42 are held in sliding contact with the spacer 36 interposed in the rod seat 35, and the valve stopper 43b is , is fixed in a predetermined position by a nut 37 screwed onto the upper end of the rod seat 35.

On the other hand, in the embodiment shown in FIG. 4, the damping valve 40 is only a negative damping valve 41, and the other damping valves 41 are omitted in the base valve part 30, and In place of this omission, a relief valve 44 is provided in the base valve section 30. By omitting the other damping valve 42 and providing the relief valve 44, this embodiment is slightly modified compared to the embodiment shown in FIG. 3.

That is, the valve housing 33 in FIG. 4 that accommodates the poppet 31α that extends over the switching valve 3 has a rod portion 33 that extends through the center of the valve disc 34 disposed between the upper end of the outer peripheral side and the cylinder 10. It has
The rod seat 35 in the previous embodiment is replaced. The valve housing 33 has an oil passage 33 in place of the oil passage 35α in the rod seat 35 of the embodiment.
d is bored, and the damping valve 41 of the damping valve 40 is arranged so as to close the upper end opening of the oil passage 33d.
is installed. The negative damping valve 41 includes a leaf valve 41α, a plate valve 41j, and a spring 4.
1C, and the spring 41C is locked to the valve disc 34.

On the other hand, in the valve disc 34, the arrangement of the inner oil passage 34α in the embodiment shown in FIG. 3 is omitted, and an oil passage 34C corresponding to the outer oil passage 34b is bored. check valve 4 to close the upper end opening of
3 is arranged. The check valve 43 is energized by a non-return spring 43α, and the non-return spring 43α is energized by a valve stopper 43A fixed by a nut 37 screwed onto the rod portion 33.
It is locked to.

The rod portion 33 is formed with an oil passage 44α that allows communication between the cylinder inner lower chamber B and the front side of the poppet 31α, and the relief valve 44 is provided in the oil passage 44α.
A spring 44C that urges the steel ball 44A; and a stopper 44d press-fitted into the oil passage 44α to lock the lower end of the spring 44c. and,
The steel ball 446 closes the oil passage 44α from the poppet 31α side, and retreats against the repulsive force of the spring 44C when the oil pressure in the lower chamber B in the cylinder becomes excessive, thereby closing the oil passage 44α. When opened, the oil in the lower chamber B is allowed to flow out to the poppet 31a side through the opened oil passage 44α.

The stopper 44d that locks the lower end of the spring 44C also locks at its lower end the upper end of the spring 31A that biases the poppet 31α downward.

The accumulator 50 that communicates with the passage in the piston rod 21 has a free piston 51 therein, as well as a gas chamber 52 and an oil chamber 53 defined by the free piston 51. In the accumulator 50, when the gas pressure in the gas chamber 52 is set to a predetermined value and oil from the cylinder upper chamber A flows into the oil chamber 53, As the free piston 51 moves, the gas chamber 52 is compressed,
The generation of air pressure in the gas chamber 52 prevents the oil in the upper chamber A in the cylinder from flowing toward the actuator 50, thereby preventing the accumulator 50 from locking the oil in the extension side of the hydraulic shock absorber. It is designed to be able to perform effectively.

The operation of the hydraulic shock absorber in the embodiment shown in Figures 3 and 4 formed as described above is not different in principle from the operation shown in Figures 1 and 2 described above. .

That is, in the embodiment shown in Fig. 3, when the external supply pressure P is supplied due to the rolling phenomenon of the vehicle, the poppet 31a rises and the switching valve 31 is in the closed state as shown in the figure. The inside of the cylinder 10 is the piston part 20
Even if the oil in the upper chamber A rises, the oil in the upper chamber A flows through the notch 13tZ of the bearing member 13, the passage α, and the passage 33α of the valve housing 330 to the outside, that is, the lower chamber B side in the cylinder and the reservoir chamber. The oil will no longer flow out to the C side, and will only flow into the oil chamber 53 in the external accumulator 50 via the passage in the piston rod 21. In the accumulator 50, the air pressure in the gas chamber 52 increases as oil flows into the oil chamber 53, thereby preventing the oil from flowing into the oil chamber 53. An oil lock state is brought about in the upper cylinder internal chamber A, and a so-called extension side oil lock state is exhibited.

And also, when in the above-mentioned extension side oil lock state,
When the oil pressure in the upper chamber A in the cylinder becomes excessive, the relief valve 24 in the piston portion 20 is opened and the oil in the upper chamber A flows into the lower chamber B, thereby eliminating the overload. That will happen.

In addition, in the above-mentioned extension side oil lock state, that is,
Even when the switching valve 31 is in the closed state, during the pressure side stroke in which the piston part 20 descends within the cylinder 10, a predetermined amount of oil in the lower chamber B flows into the upper chamber A, and other damping in the base valve part 30 occurs. It is possible to flow into the valve disk 34 through the valve 42 and into the reservoir chamber C through the oil passage 336 and the notch 33C of the valve housing 33.

In addition, in the embodiment shown in Fig. 3, when the supply of external supply pressure P is released and the switching valve 31 is in the open state, during the extension stroke, the oil in the upper chamber A in the cylinder flows through the passage α, Passage 33α of valve housing 33, switching valve 3
1 poppet 31α front side, rod seat 35 oil passage 35α,
- flows into the valve disc 34 through the damping valve 41, and the outer oil passage 34 of the valve disc 34
z, the oil flows into the lower chamber in the cylinder via the check valve 43, and the insufficient oil corresponding to the withdrawal of the piston rod 21 flows from the reservoir chamber C into the notch 3 of the valve housing 33.
It flows into the valve disk 34 via the 3C1 passage 336, merges with the above-mentioned inflow, and is replenished into the lower chamber B' in the cylinder. At this time, oil passes through the - damping valve 41, thereby generating a predetermined extension-side damping force.

Further, during the pressure side stroke, the oil in the lower cylinder chamber B flows into the cylinder upper chamber A through the check valve 23 of the piston part 20, and the oil corresponding to the intrusion volume of the piston rod 21 flows into the base cylinder. Flows into the inner oil passage 34α of the valve disc 34 through the notch 43 of the check valve 43 in the valve portion 30, and flows into the inner oil passage 34α of the valve disc 34, and the other damping valve 42
is pushed open and flows into the valve disk, and at the same time flows into the reservoir chamber C through the oil passage 33b and notch 33C of the valve housing 33. At this time, as oil passes through the other damping valve 42, a predetermined pressure side damping force is generated.

Note that when the switching valve 31 is in the communicating state, the oil in the upper chamber A in the cylinder does not flow into the actuator 50 through the passage in the piston rod 21, and the oil in the above-mentioned expansion side and compression side does not flow into the actuator 50 through the passage in the piston rod 21. A desired amount of damping force is generated during each stroke.

In addition, in the embodiment shown in Figure 4, as illustrated,
When the external supply pressure P is released, the poppet 31α is lowered, and the switching valve 31 is in the open state, the oil in the upper chamber A inside the cylinder is drained during the extension stroke in which the piston portion 20 moves up inside the cylinder 10. , through the notch 13α of the bearing member 13 and the passage 33α of the valve housing 330 to the front side of the poppet 31d. On the other hand, it flows into the lower chamber B via the check valve 43, and
It flows into the reservoir chamber C via the valve housing 330 oil passage 33A and notch 33C. Then, when the oil passes through the - damping valve 41, a predetermined expansion-side damping force is generated.

Furthermore, during the pressure side stroke in which the piston portion 20 descends within the cylinder 10, the oil in the lower chamber B flows into the upper chamber A via the check valve 23, and the oil that has flowed into the upper chamber A is The oil flows into the reservoir chamber C through the same route as in the case of the side oil, and when the oil passes through the negative damping valve 41, a predetermined pressure side damping force is generated.

In the embodiment shown in FIG. 4, when the switching valve 31 is closed due to the supply of the external supply pressure P, the oil in the upper chamber A in the cylinder is transferred to the outside through the passage α, that is, to the reservoir chamber. Since the oil in the upper chamber A side is prevented from flowing out to the C side, the oil in the upper chamber A side flows into the external accumulator 50 through the passage in the piston rod 21. Then, due to the inflow of oil into the accumulator 50, an oil lock state is brought about in the upper chamber A,
The interior of the upper chamber A enters the extension side oil lock state, and
The lower chamber B side is also in an oil lock state, and both expansion and compression sides are in an oil lock state. When an overload is generated in the lower chamber B under the condition of oil lock in the cylinder inner lower chamber B, the relief valve 44 is opened to transfer the oil pressure to the outside, that is, to the reservoir chamber C side. will be released.

In the embodiment shown in Figure 3 and Figure 4 above,
The throttle h arranged in the passage in the piston rod 21 is supposed to be formed in the upper end bracket 25, but instead of this, the throttle h arranged in the passage in the oil chamber 53 in the accumulator 50 and the passage can be formed in the upper end bracket 25. The communication hole 54 forming the communication portion may be set as a substitute for the aperture h.

〔Effect of the invention〕

As described above, according to the present invention, it not only functions as a shock absorber by generating a predetermined damping force when the vehicle is running normally, but also functions as an anti-roll function when the vehicle rolls, thereby controlling the vehicle's attitude. Since it is functional, there is no need to separately provide a hydraulic shock absorber and an attitude control device, which has the advantage of reducing costs and simplifying installation work when equipping a vehicle.

Moreover, since each hydraulic shock absorber can be independently disposed at each part of the four wheels, there is an advantage that there is no fear of space constraints in the equipment of the vehicle.

In addition, since it is possible to prevent oil leaks from the piston, repulsive force characteristics due to changes in oil amount will not occur, which would worsen the ride comfort of the vehicle or impede the running stability of the vehicle. It has the advantage of being free from any danger.

Also, the oil lock state when the anti-roll function is activated is considered to be oil lock, so it is useful for preventing rolls in vehicles with a high center of gravity such as a double-decker bus. Moreover, it is extremely effective and also has the advantage of being able to prevent a situation in which the vehicle tilts only to one side due to a change in the load when the vehicle is stopped.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of one embodiment showing the principle of the present invention, Fig. 2 is a cross-sectional view of another embodiment similar to Fig. 1, and Fig. 3 is a section related to Fig. 1. Fig. 4 is a partially cutaway front view of the embodiment specifically showing the parts related to Fig. 2, and Fig. 5 is a partially cutaway front view of the embodiment specifically showing the parts related to Fig. 2. FIG. 10...Cylinder, 20...Piston part, 30・e
・Base valve part, 31- ・Switching valve, 40@e・
Damping valve, 50...accumulator, A...upper chamber, B...lower chamber, α, 6...passage.

Claims (5)

[Claims] (1) The cylinder has a passage outside the cylinder that allows communication between an upper chamber and a lower chamber defined by the piston part inside the cylinder, and a damping valve is installed in the passage in the base valve part in the lower part of the cylinder. In the hydraulic shock absorbing device, a switching valve is disposed in the passage in the base valve portion to enable the passage to be opened and closed by external supply pressure, and the damping valve is extendable. It is formed to enable generation of damping force on the pressure side,
The hydraulic pressure is characterized in that when the switching valve is closed, the upper chamber in the cylinder is communicated with an external accumulator, and the oil in the upper chamber in the cylinder can be relieved to the lower chamber in the cylinder. Buffer device. (2) There is a passage outside the cylinder that allows communication between the upper chamber and the lower chamber defined by the piston part inside the cylinder, and a damping valve is installed in the passage in the base valve part in the lower part of the cylinder. In the hydraulic shock absorbing device, a switching valve is disposed in the passage in the base valve portion to enable the passage to be opened and closed by external supply pressure, and the damping valve is extendable. It is formed to enable generation of damping force on the pressure side,
Further, when the switching valve is closed, the upper chamber in the cylinder is communicated with an external accumulator, and the lower chamber in the cylinder is in an oil lock state, and furthermore, when the switching valve is closed, the oil cylinder in the upper chamber in the cylinder is communicated with the external accumulator. A hydraulic shock absorber characterized in that it is formed to allow relief to an inner lower chamber and relief of oil in the cylinder inner lower chamber to a reservoir chamber. (3) The hydraulic shock absorber according to claims 1 and 2, wherein the switching valve is a poppet valve. (4) The hydraulic shock absorber according to claims 1 and 2, wherein the external supply pressure is hydraulic pressure or pneumatic pressure. (5) The external accumulator and the upper chamber in the cylinder communicate with each other through a passage bored in the piston rod, and a throttle is disposed in the passage. The hydraulic shock absorber according to item 2.