JPH01106719A - Antiroll shock absorber - Google Patents

Abstract

PURPOSE:To give an antiroll function to a shock absorber by communicating an upper oil chamber in a cylinder with an accumulator oil chamber through a through-hole formed in a piston rod, a communication passage and a selector valve which gives a free flow for the accumulator and a restricted flow in the reverse direction. CONSTITUTION:An upper oil chamber A in a cylinder 10 is communicated with an oil chamber Q3 in an accumulator Q through a through-hole 21a formed in a piston rod 21 along the center axis thereof and a communication passage R in which a selector valve V is disposed. This selector valve V is arranged so as to allow hydraulic oil in the passage R to freely flow toward the accumulator Q but to restrict the flow of hydraulic oil toward the cylinder oil chamber A. Accordingly, the oil can flow freely from the cylinder 10 to the accumulator Q. When the hydraulic pressure of the accumulator oil chamber Q3 is increased, the selector valve V is changed over so as to prevent abrupt discharge of hydraulic oil from the accumulator Q. Thus, it is possible to obtain a shock-absorber which surely exhibits antiroll function with a simple arrangement.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an anti-roll shock absorber which normally functions as a shock absorber, but which can exhibit an anti-roll function when desired.

[Conventional technology]

In order to improve the running stability of a vehicle, it is necessary to effectively suppress rolling, pitching, etc. in a running vehicle, and various attitude control devices have been proposed for this purpose.

However, even with this type of conventional proposal, it is not possible to achieve desirable posture control, so the applicant first proposed a solution to the problem.
We proposed a hydraulic shock absorber, or shock absorber, as shown in the figure.

This shock absorber normally functions as a shock absorber, but when the vehicle tends to tilt due to rolling, pitching, etc., its extension is prevented, preventing the tilting described above and ensuring the grounding of the wheels. That is.

Therefore, an upper oil chamber A and a lower oil chamber B, which are partitioned and formed in the cylinder 1 by the piston part 2 that is slidably housed in the cylinder 1, normally communicate with each other via an oil passage. state, and the piston portion 2 is allowed to slide within the cylinder 1.

That is, a check valve 2α is disposed in the piston portion 2, and when the piston portion 2 moves upward in the cylinder 1 during the extension stroke, hydraulic oil from the upper oil chamber A flows into the oil passage. It flows into the lower oil chamber B through the communication position 3α of the provided on-off valve 3 and the expansion-side damping valve 4, and when the hydraulic oil passes through the expansion-side valve 4, it reaches a predetermined expansion side. A damping force is said to be generated.

On the other hand, during the pressure side stroke in which the piston part 2 descends inside the cylinder 1, a part of the hydraulic oil in the lower oil chamber B flows through the pressure side damping valve 6 in the base valve part 5 formed below the cylinder 1. When the hydraulic oil flows into the reservoir chamber C and passes through the pressure damping valve 6, a predetermined pressure damping force is generated.

When the on-off valve 3 is switched to the shutoff position 3h by external pilot pressure P, the hydraulic oil in the upper oil chamber A is transferred to the through hole 7 formed in the axial center of the piston rod 7.
α and through the communication path R connected to the through hole 7α, it is communicated only with the external 7 accumulator Q, and at this time, when the piston part 2 tries to rise inside the cylinder 1, it becomes free in the accumulator Q. The sliding movement, that is, the retraction of the piston Q1 is restricted by the gas pressure in the gas chamber Q2, thereby preventing the hydraulic oil from flowing into the oil chamber Q3 from the upper oil chamber A.

That is, when the upper oil chamber A in the cylinder 1 is communicated with the lower oil chamber B via the oil passage, the shock absorber is allowed to expand and contract, and a predetermined hydraulic shock absorbing function is exhibited, and the oil When the on-off valve 3 in the passage is shut off and the inside of the upper oil chamber A is communicated only with the 7th accumulator Q, large extension of the shock absorber is prevented and functions such as anti-roll are exerted.

[Problem that the invention seeks to solve]

However, in the earlier proposal by the applicant mentioned above, the free piston Q in the accumulator Q
There is a risk that a so-called collision sound will be generated when the actuator 1 moves forward, that is, when it returns, or that the actuator Q will become inoperable.

That is, when the on-off valve 3 is switched to the cutoff position 36, the inside of the upper oil chamber A in the cylinder 1 is exclusively communicated with the oil chamber Q3 of the accumulator Q, and at this time the piston portion 2
If there is a situation where the free piston Ql is forcibly raised inside the cylinder 1, the free piston Ql in the accumulator Q will move backward so as to compress the gas chamber Q2.

When the above rising situation is resolved, the free piston Q1 returns and the hydraulic oil in the oil chamber Q3 flows into the upper oil chamber A, but at this time, the hydraulic oil suddenly flows into the oil chamber Q.
3, the free piston Q1 will collide with a so-called stopper portion, and there is a risk that a so-called collision sound will be generated.

Therefore, if a throttle 0 is provided in the accumulator Q or a communication path R connected to the accumulator Q, but if the throttle effect of the throttle 0 is made to be a dog, then the upper oil chamber A will be connected to the oil chamber Q3.
Since the flow of hydraulic oil into the oil chamber Q3 cannot be expected and the desired expansion prevention cannot be achieved, priority must be given to the flow of hydraulic oil from the upper oil chamber A side into the oil chamber Q3.As a result, the above-mentioned Therefore, the occurrence of collision noise cannot be avoided.

Therefore, in addition to the above-mentioned collision noise, the free piston Q1 repeatedly collides with the stopper portion, leading to a failure of the accumulator Q itself and the inoperability of the accumulator Q. There is a certain inconvenience.

Therefore, in view of the above-mentioned circumstances, the present invention has been devised to prevent the accumulator from malfunctioning, but also to enable the accumulator to operate as desired and to fully exhibit its desirable anti-roll and other functions. The purpose of this product is to provide a new anti-roll shock absorber.

[Means for solving problems]

In order to achieve the above object, the structure of the anti-roll shock absorber according to the present invention is such that when an upper oil chamber and a lower oil chamber that are divided and formed in a cylinder communicate with each other through an oil passage outside the cylinder. In the anti-roll shock absorber, which is formed to be able to expand and contract and is not allowed to expand when the oil passage is closed, an upper oil chamber in the cylinder is bored in the axial center of the piston rod. The oil chamber is connected to an oil chamber in the accumulator through a through hole and a communication passage connected thereto, and a switching valve is disposed in the passage or in the accumulator,
In addition, the switching valve is formed so that the hydraulic oil flows into the oil chamber in the accumulator in a free flow, and the hydraulic oil flows out from the oil chamber in the upper accumulator in a throttled flow. This is a feature of the system.

[For production]

When the upper oil chamber and the lower oil chamber in the cylinder are communicated via an oil passage, and the piston part slides up and down in the cylinder, the sliding of the piston part in the cylinder is allowed. This allows it to expand and contract, thereby exerting a predetermined damping effect.

Furthermore, when the oil passage is blocked, the hydraulic oil in the upper oil chamber inside the cylinder is allowed to flow only into the accumulator, and its expansion is prevented, so that the desired anti-roll and other functions are not achieved. Demonstrated.

Further, the hydraulic oil in the upper oil chamber inside the cylinder freely flows into the 7 accumulator, but when it returns, a throttling effect is exerted to prevent the free piston in the accumulator from returning rapidly.

〔Example〕

Hereinafter, the present invention will be described in detail based on illustrated embodiments.

Figure 1 shows the principle of an anti-roll shock absorber according to the present invention, and the anti-roll shock absorber is formed to be independently disposed at each of the four wheels of a vehicle.

That is, this shock absorber has an upper oil chamber A and a lower oil chamber B partitioned by the piston part 20 in the cylinder 10.
The upper oil chamber A and the square oil chamber B-
It has a passage L that communicates between and 0.

The base valve section 1 in the lower part of the cylinder 10 is
1 includes an on-off valve 30 and a damping force generating section 40.

The shock absorber has an upper end connected to the vehicle body side and a lower end connected to the axle side of the vehicle.

An outer cylinder 12 and an inner cylinder 13 are disposed outside the cylinder 10, and the gap between the cylinder 10 and the inner cylinder 13 is an annular gap α, and the gap between the inner cylinder 13 and the outer cylinder 12 is The space between them is said to be reservoir room C.

A communication hole 10α is bored in the upper end of the cylinder 1, and the upper oil chamber A in the cylinder 10 and the annular gap α
It is possible to communicate with

On the other hand, a boat 11α is formed in the base valve portion 11, and one end of the port 11α opens into the lower oil chamber B in the cylinder 1'O, and the other end opens into the annular gap α.
It is said to open inward.

That is, the oil passage described above has a communication hole 10α and an annular gap α.
and port 11α, and the oil passage L(
In this embodiment, the on-off valve 30 is disposed in the port 1ia).

The upper end sides of the cylinder 10, outer cylinder 12, and inner cylinder 13 are closed with a bearing member 14.
The lower end sides of the outer cylinder 12 and the inner cylinder 13 are closed by a bottom member 15 having the base valve portion 11.

The piston part 20 has a piston body 22 connected to the lower end of a piston rod 21 that is inserted through the axial center of the seven-ring member 14, and the piston body 22 moves inside the cylinder 10 into the upper oil chamber A. and a lower oil chamber B.

A port 22α is formed in the piston body 22, and a check valve 2 is inserted into the port 22α.
3, allowing the hydraulic oil in the lower oil chamber B to flow into the upper oil chamber A through the check valve 23.

Also, a relief valve 2 is provided in the piston body 22.
4 is provided, and the relief valve 24 is connected to the upper oil chamber A.
When the oil pressure inside becomes excessive, it becomes open and the excessive oil pressure is released into the lower oil chamber B.

A small diameter through hole 21 is provided in the axial center of the piston rod 21.
α is bored, and the lower end of the through hole 21α is connected to the cylinder 1.
The piston rod 21 opens into the upper oil chamber A in the piston rod 21, and its upper end opens to the outside from near the upper end of the piston rod 21.

An external communication path R is connected to the through hole 21α, and an accumulator Q is connected to the communication path R, and the accumulator q and the upper oil chamber A are connected to the through hole 21α and the communication path R. It is said that they will communicate through it.

A switching valve V, which will be described later, is provided in the communication path R.

The accumulator Q has a free piston Q1 inside, and a gas chamber Q2 on the back side and an oil chamber Q3 on the front side, which are defined by the free piston Q1.

The accumulator Q sets the gas pressure in the gas chamber Q2 quite high, and when the oil pressure in the oil chamber Q3 becomes considerably large, the free piston Q1 is retreated and the gas chamber Q2 is compressed to a certain extent. , are formed to prevent further significant compression.

That is, even if the shock absorber tends to elongate when the hydraulic oil in the upper oil chamber A is prevented from flowing into the lower oil chamber B through the oil passage, the shock absorber will not elongate. It is designed to prevent

The switching valve V has a free position v1 that allows the free flow of hydraulic oil in the communication passage R, and a throttle position ■2 that prevents the free flow of hydraulic oil in the communication passage R. Although the switching valve is in the free position v1, when the oil pressure difference between the upper oil chamber A side that is the upstream side of the switching valve and the oil chamber Q3 side that is the downstream side of the switching valve is larger on the oil chamber Q3 side,
It is formed so that it can be switched to the aperture position v2.

That is, the switching valve V is configured so that when the hydraulic oil that has flowed into the oil chamber Q3 from the upper oil chamber A side via the free flow position (1) attempts to return from the oil chamber Q3 to the upper oil chamber A. , and is switched to the throttle position V2 to prevent the hydraulic oil in the oil chamber Q3 from being suddenly discharged.

As a result, when the free piston Q1 that has retreated within the accumulator Q moves forward to return, the free piston Q1 is prevented from colliding with the so-called stopper portion, preventing the generation of collision noise and preventing the collision from occurring. This will prevent malfunction of the accumulator Q due to damage to the free piston Q1 or stopper portion.

The on-off valve 30 is disposed in the extending portion of the oil passage, that is, in the port 11α in the base valve portion 11, and has a communication position 30α and a shutoff position 30A. Although it is in the communication position 30α, it is formed so that it can be switched to the cutoff position 30A using a pilot pressure P from the outside as the operating pressure.

Therefore, when the on-off valve 30 is in the communication position 30α, the hydraulic oil from the upper oil chamber A flows into the lower oil chamber B through the oil passage, and the expansion of the shock absorber is prevented. It will be allowed.

When the on-off valve 30 is switched to the cutoff position 30h, the hydraulic oil in the upper oil chamber A is prevented from flowing into the lower oil chamber B through the oil passage, and the accumulator Q is activated. As a result, the shock absorber is prevented from expanding.

In the illustrated embodiment, the switching valve V is arranged in the communication path R, but instead of this, it is assumed that the switching valve V is arranged in the 7-cumulator Q. Of course, it is also a good thing.

The damping force generating section 40 includes an expansion side valve 41 and a compression side valve 42 which are formed independently, and a check valve 43 is arranged in parallel with the compression side valve 42.

The extension valve 41 is disposed in the port 11α, and when the hydraulic oil from the upper oil chamber A flows into the lower oil chamber B via the oil passage, the expansion side valve 41 is arranged in the port 11α. It is formed to allow circulation and generate a predetermined rebound damping force.

The pressure side valve 42 is disposed in the boat IIA that communicates the lower oil chamber B and the reservoir chamber C, and when hydraulic oil from the lower oil chamber B flows into the reservoir chamber C. In addition, it is formed to allow the flow of the hydraulic oil and to generate a predetermined compression damping force.

The check valve 43 is formed to allow hydraulic oil from the reservoir chamber C to flow into the lower oil chamber B.

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

First, when this shock absorber is to function as a normal so-called shock absorber, the pilot pressure P is released so that the on-off valve 30 is in the communication position 30α.

At this time, when the piston part 20 moves up inside the cylinder 10, the hydraulic oil in the upper oil chamber A flows through the oil passage, that is, the on-off valve 30 and the extension valve 41 in the oil passage. The hydraulic oil corresponding to the volume of the piston rod 21 withdrawn from the reservoir chamber C flows into the lower oil chamber B through the check valve 43.
The lower oil chamber B is replenished via.

When the hydraulic oil passes through the expansion valve 41, a predetermined expansion damping force is generated.

On the other hand, contrary to the above, when the piston part 20 is to descend within the cylinder 10, a part of the hydraulic oil in the lower oil chamber B flows into the upper oil chamber A via the check valve 23, and at the same time, In the lower oil chamber B, an amount of hydraulic oil corresponding to the entering volume of the piston rod 21 flows out into the reservoir chamber C via the pressure side valve 42.

Then, when the hydraulic oil passes through the pressure side valve 42, a predetermined pressure side damping force is generated.

That is, when the on-off valve 30 is in the communication position 30α, the present shock absorber is freely expanded and contracted to exhibit a predetermined damping function, and functions as a normal so-called shock absorber.

Next, when the present shock absorber is to exhibit an anti-roll function, the on-off valve 30 is switched to the cutoff position 30h.

As a result, the oil passage becomes blocked and the upper oil chamber A
The hydraulic oil inside is allowed to flow only into the oil chamber Q3 inside the accumulator q.

Therefore, when the piston portion 20 moves up within the cylinder 10, the hydraulic oil in the upper oil chamber A flows into the oil chamber Q3 via the free position 1 of the switching valve V.

However, the gas pressure in the gas chamber Q2 in the accumulator Q is set to be quite large as described above, and although a small amount of hydraulic oil is allowed to flow into the oil chamber Q2, a large amount of hydraulic fluid is allowed to flow into the oil chamber Q2. will be blocked.

In other words, the hydraulic oil in the upper oil chamber A cannot flow out to other parts, and the so-called extension side oil lock state is caused when the upper oil chamber A
As a result, the shock absorber is prevented from expanding.

Therefore, when rolling or pitching occurs in the vehicle, the extension of the shock absorber that is about to be extended is prevented, and therefore, the rolling or pitching is prevented in advance. It turns out.

By the way, when the above-mentioned rolling or pitching is canceled, the pilot pressure P to the on-off valve 30 is also released, and at this time, the high pressure in the oil chamber Q3 in the accumulator Q is also released. That will happen.

At this time, due to the return of the above-mentioned shutoff valve 30 to the communication position 30α, the hydraulic oil trapped in the upper oil chamber A will flow into the lower oil B side via the oil passage. , the oil pressure in the upper oil chamber A decreases. Therefore, there is a difference in oil pressure between the upstream side of the switching valve V communicating with the upper oil chamber A and the oil chamber Q3 downstream of the switching valve V. occurs, and the switching valve V moves to the throttle position v2 due to the oil pressure difference.
It will be switched to.

Therefore, due to the throttling effect at the throttling position v2, the hydraulic oil in the oil chamber Q3 is not suddenly discharged to the lower pressure side of the upper oil chamber A, thereby preventing the free piston Q1 from returning rapidly. and the free piston Q1
Collision with the so-called stopper portion is avoided.

That is, in the accumulator Q, the free piston Q1
Collision noise is not generated, and the free piston Q1 is prevented from being damaged due to collision, and the accumulator is prevented from becoming inoperable.

Note that when the above-mentioned expansion side oil is locked in the upper oil chamber A, when abnormally high pressure is generated in the upper oil chamber A, the relief valve 24 disposed in the piston body 22 of the piston portion 2 is opened. Therefore, the upper oil chamber A
The hydraulic oil inside will flow out into the lower oil chamber B.

Fig. 2 shows a specific embodiment of the present shock absorber shown in principle in Fig. 1, but since the basic structure is the same, it is particularly difficult to compare the implementation shown in Fig. 1 above. The following description focuses on parts that are different from those in the example.

First, the bearing member 14, which is disposed so as to close the upper end sides of the cylinder 10, the outer cylinder 12, and the inner cylinder 13, has a communication hole 10α formed in the upper end of the cylinder 10 in FIG. It is assumed that a replacement notch 14α is formed.

Also, above the bearing member 14, the outer cylinder 1
A gasket case 16 housing an oil seal 17 is screwed onto the inner periphery of the upper end of 2.

In this embodiment, the base valve 11 includes a bottom member 1
The valve housing 18 is formed separately so as to be supported from below by the inner cylinder 13 and the valve housing 18 which is disposed to be fitted inside the lower end of the inner tube 13 and the cylinder 10.

The valve housing 18 has a horizontal hole 18α drilled in the radial direction and a vertical hole 18h bored in the solid shaft core. It has an opening/closing valve 30 in the flow path formed (corresponding to the boat 11α in FIG. 1), and an extension valve 41 in the damping force generating section 40.

Note that the tip of the horizontal hole 18α is connected to the cylinder 10 and the inner cylinder 1.
Of course, the tip of the vertical hole 18h opens into the lower oil chamber B in the cylinder 10.

The on-off valve 30 is formed in the form of a poppet valve that allows communication and isolation between the horizontal hole 18α and the vertical hole 18A, and a poppet 31 that is slidably housed in the vertical hole 18b. I have it.

The poppet 31 has a spring 3 adjacent to its upper end.
2, the free piston 33 is energized downward and is adjacent to the lower end of the free piston 33.
It is formed so that it is raised together when the is raised.

Note that there is a port 1 on the back side of the free piston 33.
Pilot pressure P acts through 5α.

Therefore, in this embodiment, when the poppet 31 rises, communication between the horizontal hole 18α and the vertical hole 186 is cut off, and the cutoff position 30h (see Figure 1) K is reached, and the poppet 31 is moved upward. When descending, the horizontal hole 18α and the vertical hole 1
8h is enabled, and the communication position 30α (see FIG. 1) is established.

The expansion side valve 41 includes a valve seat 41α disposed across the vertical hole 18h, and a valve seat 41α disposed across the vertical hole 18h.
An annular leaf valve 41A set to α and a spring 4 backing up the annular leaf valve 41A from the rear side.
1C, and a stopper 41d that locks the rear end of the spring 41C.

When the poppet 31 is lowered, the hydraulic oil flows through the horizontal hole 18α into the lower oil chamber B by opening the annular leaf valve 41h (pushing it up in the figure). At this time, a predetermined rebound damping force is generated.

On the other hand, the central rod portion 18C of the valve housing 18
The pressure side valve 42 in the damping force generating section 40 is disposed on the outer periphery of the damping force generating section 40.
is installed.

The pressure side valve 42 has a port 18d bored on the outer peripheral side of the valve housing 18 along the axial direction of the portion.
An annular leaf valve 42α disposed so as to close the upper end opening (corresponding to the port 11b in Figure 1)
and a disk 426 disposed in contact with the upper surface of the annular leaf valve 42α so as to be slidable in the vertical direction;
A spring 4 that urges the disk 42h downward.
2C, and a stopper 42d that locks the rear end of the spring 42C.

A cutout hole is formed in each of the stopper 42d and the disc 42h, so that the hydraulic oil from the lower oil chamber B above flexes the inner peripheral end of the annular leaf valve 42α into the boat 1Bd. When the hydraulic oil flows into the lower oil chamber B, the hydraulic oil flows into the lower oil chamber B when a predetermined pressure-side damping force is generated and the hydraulic oil from the port 18d raises the disc 42b. It is formed in such a way that it becomes

That is, in this embodiment, the pressure side valve 42 also serves as a check valve 43 (see FIG. 1).

Note that a cutout hole 1 is provided in the lower leg of the valve case 18.
8g is formed to allow communication between the port 18d and the reservoir chamber C.

Next, the check valve 23 in the piston portion 20 is an annular leaf valve disposed to close the upper end opening of the port 22α bored in the piston body 22, and the check valve 23, which is the annular leaf valve, The non-return spring 23α is energized from above, and the non-return spring 23α is applied to the upper valve stopper 23h.
The rear end side is said to be locked.

Furthermore, the relief valve 24 in the piston part 20 is formed in a part of the lower end spigot of the piston rod 21, and the relief valve 24 communicates with a through hole 21α bored in the axial center of the piston rod 21. A steel ball 2475 arranged to close the passage 24α from the lower oil chamber B side
, a spring 24C that urges the steel ball 24b in the closing direction, and a stopper 24d that locks the rear end of the spring 24C. When the ball 24h overcomes the repulsive force of the spring 24C and is retreated, hydraulic oil is allowed to flow.

The piston body 22 of the piston portion 20 is fixed by a nut 25 screwed onto the lower end of the piston rod 21, and a cap 2 is attached to the upper end of the piston rod 21.
6 is fixed to the cap 26, and a cover 27 is provided vertically on the cap 26.

The switching valve V located in the communication path R that communicates the through hole 21α in the piston rod 21 with the external 7-cumulator Q is as follows:
In this embodiment, it is formed as shown in Figure 3.

That is, a spool 51 is slidably housed within the valve body 50, and the spool 51 is biased by a spring 52 adjacent to one end.

The valve body 50 also includes a pilot port 5.
3 and 54 are drilled, and one pilot port 5
3 communicates with the oil chamber Q3 of the accumulator Q via the communication path R, and also connects to the tip of the front P spool 51 (the right end in the figure).
It is open on the side.

The other pilot port 54 communicates with the upper oil chamber A in the cylinder 10 via the communication path R, and opens at the rear end (left end in the figure) of the spool 51.

Further, a land portion 50α is formed at the center of the inner circumference of the valve body 50, and annular groove portions 50A and 50C are formed to sandwich the land portion 50α.

Note that the spool 51 has an annular recess 51 in the center of its outer periphery.
α is formed, and the annular recess 51α substantially faces the land portion 50α and the annular grooves 50b and 500.

Therefore, when the hydraulic oil flows from the upper oil chamber A side in the cylinder +10 to the oil chamber Q3 side of the 7th cumulator Q, the spool 51 is stabilized in the state shown in the figure, and the free flow of the hydraulic oil is allowed. Become.

On the other hand, when the hydraulic oil from the oil chamber Q3 side returns to the upper oil chamber A side, the hydraulic pressure at that time acts on the front end side of the spool 51 via the pilot port 53, causing the spool 51 to retreat ( As the spool 51 retreats, the annular recess 51α, the land 50α, and the recessed groove 50. ? The gap formed by this is restricted to a small size, and the flow of hydraulic oil becomes a restricted flow.

Figure 4 shows another embodiment of the switching valve V of the present invention, which is formed into a so-called poppet type.

That is, a poppet 55 is slidably housed in the valve body 50, and is biased in the backward direction (rightward direction in the figure) by a spring 52 adjacent to the tip of the poppet 55.

The rear end side of the poppet 55 is communicated with the accumulator Q3 side, and the front end side of the poppet 55 is communicated with the upper oil chamber A side.

An oil hole 55α is formed in the rear end side of the poppet 55, and a core oil hole 55α is formed in the center of the poppet 55 in the diametrical direction.
It is connected to h.

In addition, the kernel oil hole 55A has an orifice 55 that is bored at the tip side of the poppet 55 and opens at the tip of the poppet 55.
C is formed.

An enlarged diameter portion 50d is formed on the central inner periphery of the valve body 50, and the enlarged diameter portion 50d is separated from the enlarged diameter portion 50d so that the distal end of the poppet 55 faces the annular seat portion. It is said to have a weight of 50g.

Note that the tip of the spring 52 is said to be stopped by a stopper 56, but the stopper 56 has a communication hole 56.
α allows the flow of hydraulic oil.

Therefore, when hydraulic oil is introduced from the upper oil chamber A side, the poppet 55 enters the stable state shown in the figure, and the hydraulic oil flows through the oil holes 55h and 55α of the poppet 55.
It will freely flow to the oil chamber Q3 side of the cumulator Q.

On the other hand, when hydraulic oil flows in from the oil chamber Q3 side, hydraulic oil flows into the oil holes 55α and 55b of the poppet 55, and due to the influence of the orifice 55C, the front end and rear end of the poppet 55 are raised. A hydraulic pressure difference is generated between the poppet 55 and the poppet 55 to move forward (to the left in the figure), thereby narrowing the annular gap formed between the tip of the poppet 55 and the annular seat portion 50g. Therefore, the flow of hydraulic oil from the oil chamber Q3 side becomes a restricted flow.

Of course, the operation of the anti-roll shock absorber in the embodiment shown in FIG. 2 is not different from the operation shown in FIG. 1 described above.

〔Effect of the invention〕

As described above, according to the present invention, when the vehicle is normally running, it not only generates a predetermined damping force and functions as a so-called shock absorber, but also exhibits an anti-roll function when the vehicle rolls, and controls the vehicle's attitude. also works, so
There is no need to separately provide a shock absorber and a posture control device, and there are advantages in that costs can be reduced and installation work can be simplified when equipping a vehicle.

Further, since each anti-roll 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.

Even if an accumulator with a free piston is used to exert the anti-roll function, the switching valve allows free flow when the hydraulic oil flows into the accumulator, and vice versa. When flowing out, the flow is restricted, thereby preventing the free piston from colliding with the stopper portion, preventing collision noise, and preventing inoperability due to damage to the accumulator.

Furthermore, the oil lock state when the anti-roll function is activated is the oil lock on the extension side, which is extremely effective in preventing rolls of vehicles with high centers of gravity such as double-decker buses. This 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 the drawing]

Fig. 1 is a longitudinal sectional front view of an embodiment showing the principle of the present invention, and Fig. 2 is a longitudinal sectional front view partially broken away of an embodiment specifically showing the parts related to Fig. 1. Figures 1 and 83 and Figure 4 are sectional views showing respective embodiments of the switching valve according to the present invention, and Figure 5 is a diagram showing the principle of a conventional hydraulic shock absorber. [Explanation of the attached numbers] 10...Cylinder, 20...Piston part, 21...
・Piston rod, 21α...Through hole, A...Upper oil chamber, B...Lower oil chamber, L...Oil passage, Q...Accumulator, Ql...Free piston, Ql...・Gas chamber, Q3...Oil chamber, R...Communication passage, ■...Switching valve. Q3

Claims (3)

[Claims] (1) The upper oil chamber and the lower oil chamber, which are defined in the cylinder by a piston that slides inside the cylinder, can expand and contract when they communicate with each other via an oil passage outside the cylinder. In addition, in the anti-roll shock absorber that is formed so that the oil passage cannot be extended when the oil passage is closed, the upper oil chamber in the cylinder has a through hole bored in the axial center of the piston rod and a through hole formed in the axial center of the piston rod. It communicates with the oil chamber in the accumulator through a connected communication passage, and a switching valve is disposed in the communication passage or in the accumulator, and the switching valve communicates with the oil chamber in the accumulator. An anti-roll shock absorber characterized in that it is formed so that the inflow of hydraulic oil is a free flow, and the outflow of the hydraulic oil from the oil chamber in the accumulator is a throttle flow. (2) The anti-roll shock absorber according to claim 1, wherein the switching valve is configured to be operated to switch using the hydraulic pressure in the communication passage as a pilot to allow a restricted flow of the hydraulic fluid. (3) The anti-roll shock absorber according to claim 1, wherein the accumulator has a free piston, the front side of the free piston is an oil chamber, and the rear side of the free piston is a gas chamber. .