JPH0642571A - Hydraulic buffer - Google Patents

Abstract

PURPOSE:To provide a hydraulic buffer which contributes to the downsizing and is optimum to improve the mountability on vehicles. CONSTITUTION:A damping force adjusting part 10 is provided with a casing 11, a solenoid valve 20 which is accommodated on the opening end side within the casing 11 and provided with an adjacent magnetic member 23 on its inner circumference, a valve element 30 which is arranged in an elevatable manner on the upper end side of the solenoid 20, and a shaft sealing member 15 which is provided with a bearing member 16 on its inner circumference in an adjacent manner while bringing the valve element 30 into contact with the outer circumference in a slidable manner and covers the upper end of the cylinder 1. When the casing 11 is continuously arranged to the outer cylinder 5, the upper end side of the cylinder 1 is faced on the inner circumference side of the solenoid 20 and the valve element 30 while a piston rod 2 is inserted into the axial core part of the sealing member 15. A passage is formed in the sealing member 15, the valve element 30 and the magnetic member 23 so that communication from the rod side chamber R1 to the reservoir chamber R3 may be possible, and at the same time, the passage may be closed when the valve element 30 is lowered to the bottom.

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 hydraulic shock absorber that adjusts the level of generated damping force using a solenoid.

[0002]

2. Description of the Related Art Conventionally, various hydraulic shock absorbers have been proposed for adjusting the level of generated damping force using a solenoid.

For example, in the uniflow type hydraulic shock absorber shown in FIG. 4, the tip end side of the piston rod 2 is inserted into the cylinder 1 so that the piston rod 2 can be retracted and retracted.
The piston portion 3 slidably accommodated in the cylinder 1 is continuously provided at the tip of the cylinder 1, and the piston portion 3 partitions and forms the rod side chamber R1 and the piston side chamber R2 in the cylinder 1.

The piston part 3 has an extension side damping valve 3a.
Also, a check valve 3b is provided, which enables the rod side chamber R1 to communicate with the piston side chamber R2 via the damping valve 3a and the piston side chamber R2 to communicate with the rod side chamber R1 via the check valve 3b.

In the hydraulic shock absorber, the base valve portion 4 is arranged inside the lower end of the cylinder 1, and the outer cylinder 5 is arranged on the outer periphery of the cylinder 1, and the space between the outer cylinder 5 and the cylinder 1 is arranged. A reservoir chamber R3 is formed in the.

The base valve portion 4 is provided with a compression side damping valve 4a and a check valve 4b, and the piston side chamber R2 communicates with the reservoir chamber R3 via the damping valve 4a and the check valve 4b. The reservoir chamber R3 can communicate with the piston side chamber R2.

On the other hand, the hydraulic shock absorber has a damping force adjusting portion 10 disposed near the upper ends of the cylinder 1 and the outer cylinder 5, and the damping force adjusting portion 10 operates oil from the rod side chamber R1. It is possible to select whether or not the inflow into the reservoir chamber R3 is possible.

The damping force adjusting unit 10 in this conventional example has a casing 11, a solenoid 12, a valve body 13 and a valve guide 14, and the solenoid 12 is provided in the casing 11. Also, the valve body 13 is housed, and the valve guide 14 closes the opening end of the casing 11 to form a so-called cartridge, which allows the piston rod 2 to be inserted into the axial center portion of the shock absorber main body when continuously connected to the shock absorber main body. Is configured to.

Further, in terms of internal structure, the damping force adjusting portion 10 interposes a valve body 13 on the upper end side of a valve guide 14 that closes the opening end of the casing 11 so as to be able to move up and down.
The solenoid 12 is arranged above the valve body 13.

Then, when the solenoid 12 is excited, the valve body 13 rises, the flow passage that allows the rod side chamber R1 to communicate with the reservoir chamber R3 is opened, and the reservoir chamber R3 for the hydraulic oil from the rod side chamber R1 is opened. Is set to allow inflow to.

By the way, the above-mentioned flow path is formed by the valve guide
An annular groove 14a which is formed on the inner circumference of the piston rod 2 to form a gap between the annular groove 14a and the outer circumference of the piston rod 2, and the annular groove 14a.
And an oil hole 14b that is opened in the radial direction on the upper end side of the valve guide 14 and the valve guide 1 that communicates with the oil hole 14b.
4, an annular groove 14c opening to the outer circumference of the upper end of the valve guide 14, and a notch hole 14d vertically formed on the outer circumference of the lower end of the valve guide 14 to allow communication between the valve body 13 side and the reservoir chamber R3 side. There is.

The cutout hole 14d is formed in the valve guide 14
Is formed thickly on the outer peripheral side of the lower end of the cylinder 1 and is opened at a portion that closes the upper end of the cylinder 1 and the upper end of the outer cylinder 5.

On the other hand, the valve body 13 has the annular groove 1
4c are adjacent to each other so as to close from the outer periphery on the upper end side of the valve guide 14, and the annular groove 1
4c is closed, and the annular groove 14c is opened when it is raised.

Therefore, according to this conventional hydraulic shock absorber,
Since the damping force adjusting unit 10 is formed into a cartridge by accommodating predetermined components in the casing 11, the product test of the cartridge-shaped damping force adjusting unit 10 is separate from the product test of the shock absorber body. It is possible to reduce the risk of production of defective hydraulic shock absorbers after the damping force adjusting section 10 is connected in series, and it is possible to improve the economical efficiency in the production of the hydraulic shock absorbers. .

On the other hand, according to this conventional hydraulic shock absorber, as long as the solenoid 12 is excited and the flow path in the damping force adjusting section 10 is opened, the piston rod 2 is retracted into the cylinder 1 on the pressure side stroke. At times, the piston portion 3 descends in the cylinder 1, and at this time, operating oil that is deficient in the rod side chamber R1 flows from the piston side chamber R2 through the check valve 3b on the extension side, and excess operation occurs in the piston side chamber R2. Oil also flows into the rod side chamber R1 via the check valve 3b.

The surplus oil that has flowed into the rod-side chamber R1 from the piston-side chamber R2 flows out into the reservoir chamber R3 via the damping force adjusting section 10 in the so-called open state.

Further, from the inside of the cylinder 1 to the piston rod 2
The piston portion 2 rises in the cylinder 1 during the extension side stroke, in which the piston side chamber R
2 is replenished from the reservoir chamber R3 via the pressure-side check valve 4a, and excess hydraulic oil in the rod-side chamber R1 is supplied to the reservoir chamber R3 via the damping force adjusting unit 10 in the open state. It will be leaked.

Therefore, as long as the solenoid 12 is excited, the rod-side chamber R1 is not affected by any of the strokes.
The hydraulic oil from each side will flow out to the reservoir chamber R3 via the damping force adjusting unit 10 in the open state, and at this time, the damping valves 3a and 4a on each side are placed in an inoperative state,
The damping force adjusting unit 10, that is, the low damping force set by the valve body 13 is generated.

On the other hand, in the damping force adjusting section 10, when the excitation of the solenoid 12 is released and the valve body 13 descends, the annular groove 14c formed in the valve guide 14 is closed by the valve body 13. As a result, the flow path that connects the rod side chamber R1 and the reservoir chamber R3 is closed.

Therefore, during the extension side stroke, the rod side chamber R1
From the piston side chamber R2 is released under a high cracking pressure during the pressure side stroke, and flows into the piston side chamber R2 through the expansion side damping valve 3a that is released under a high cracking pressure. Will flow into the reservoir chamber R3 via the compression side damping valve 4a.

Then, the damping valves 3a, 4a on each side are opened under a high cracking pressure to allow the working oil to flow, so that a high damping force is generated.

Therefore, according to the above conventional hydraulic shock absorber,
By releasing the excitation to the solenoid 12 when required, the generated damping force can be increased. For example, when the hydraulic shock absorber is mounted on a vehicle, a low damping force is normally generated and the ride comfort is soft. It becomes possible to change to a state in which a high damping force is generated at the time of attitude control during sudden braking, sudden start or roll while improving the running stability of the vehicle. .

[0023]

However, it has been pointed out that the conventional hydraulic shock absorber described above has a disadvantage in that the expansion / contraction stroke cannot be made large.

That is, in the above conventional hydraulic shock absorber,
The damping force adjusting unit 10 is made into a cartridge so that the opening end of the casing 11 is closed by a valve guide 14, and the valve body 13 and the solenoid 12 are housed in series in a space defined by the inside thereof. I am trying.

When the damping force adjusting section 10 is connected to the shock absorber main body, the valve guide 14 is connected to the cylinder 1.
Is set to be a shaft sealing member that closes the upper end of the.

Therefore, in the hydraulic shock absorber, the damping force adjusting portion 10 is arranged outside the shock absorber main body in the axial direction, and the hydraulic shock absorber is arranged, for example, in a vehicle. From the perspective of the mounting space in
Since it is necessary to shorten the cylinder 1, the extension and contraction stroke of the hydraulic shock absorber is limited by the shortened length of the cylinder 1, and there is a concern that effective damping characteristics may not be obtained.

The present invention was made in view of the above-mentioned circumstances, and an object thereof is to ensure a predetermined expansion / contraction stroke and realize an effective damping characteristic as desired, for example, Of course, the present invention is to provide a hydraulic shock absorber which is optimal not only for mounting on a vehicle but also for shortening its size and for improving mountability on a vehicle.

[0028]

In order to achieve the above-mentioned object, the structure of the present invention has a structure in which a rod side chamber and a piston side chamber are provided continuously in the cylinder, which are connected to the tip of a piston rod which is inserted into and retractable from the cylinder. To the reservoir chamber formed outside the cylinder of the rod side chamber via the damping force adjusting unit by the excitation of the solenoid in the damping force adjusting unit distributed outside the cylinder when the piston unit that forms It is formed to select whether or not to communicate with each other, and a low damping force is generated in the damping force adjusting unit, while the damping valve provided in the piston unit and the base valve unit inside the lower end of the cylinder are arranged. In a hydraulic shock absorber formed so that a high damping force is generated in the damping valve installed, the damping force adjusting portion has an opening end that is located above the outer cylinder arranged outside the cylinder. A casing formed so as to be continuously connected to the inner circumference, a solenoid that is housed on the opening end side in the casing and has a magnetic member adjacent to the inner circumference, and a solenoid that is vertically movable on the upper end side of the solenoid. And a shaft sealing member that closes the upper end of the cylinder by providing a bearing member adjacent to the inner periphery of the valve body while slidingly contacting the outer periphery of the valve body. At the time of continuous installation, the upper end side of the cylinder is made to face the inner peripheral side of the solenoid and the valve body while the piston rod is inserted through the shaft core portion of the shaft sealing member. In addition, a flow path is formed which allows the rod side chamber to communicate with the reservoir chamber, and the flow path is formed so as to be closed when the valve body is at the lowest position.

[0029]

Therefore, the damping force adjusting portion in the form of a cartridge is integrated with the shock absorber main body by connecting the open end of the casing constituting the cartridge to the outer cylinder forming the shock absorber main body by welding or the like. At the same time, the upper end of the cylinder is exposed to the solenoid and the inner peripheral side of the valve body. Therefore, even if the damping force adjusting portion is provided outside the cylinder, the entire length of the hydraulic shock absorber is reduced. Do not make them big.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following description will be given based on the illustrated embodiment, but even in the hydraulic shock absorber according to one embodiment of the present invention,
As shown in FIG. 1, it is formed in a uniflow type, and has the same configuration as the above-described conventional example (see FIG. 4) except that the configuration of the damping force adjusting unit 10 is different.

Therefore, the same reference numerals are given to the same portions in the configuration and detailed description thereof will be omitted, and the structure of the damping force adjusting portion 10 in the present invention will be described below.

That is, as shown in FIG. 2, the damping force adjusting section 10 includes a casing 11, a solenoid 20, and a valve body 30.
The shaft sealing member 15 is included, and the damping force adjusting unit 10 is configured as a so-called cartridge by housing the components such as the solenoid 20 and below in the casing 11.

In the illustrated example, the casing 11 has a body portion 11a which is formed in a substantially cylindrical shape and is located at the lower end side in the figure, and a cap portion 11b which is continuously provided at the upper end of the body portion 11a.
The main body 11a is formed such that the outer periphery of its opening end, which is the lower end in the figure, is connected to the inner periphery of the upper end of the outer cylinder 5 by welding or the like, and the solenoid is provided on the inner periphery of the opening end side. It is formed so as to accommodate 20.

A seal 11c, the inner periphery of which is in sliding contact with the outer periphery of the piston rod 2, is housed in the cap portion 11b on the upper end side.

In the illustrated example, the main body 11a forming the casing 11 is made of a magnetic material.

The solenoid 20 is housed in the casing 11 so as to prevent it from rattling, and is housed in a liquid-tight structure by the distribution of the seal members 21 and 22.
A cylindrical magnetic member 23 is provided adjacent to the inner periphery of the magnetic member 23.

The inner periphery of the magnetic member 23 is said to be adjacent to the outer periphery on the upper end side of the cylinder 1 when the damping force adjusting portion 10 is connected to the shock absorber main body.
Is a kerf 23a opened along the axial direction thereof.
And the kerf 23a has the damping force adjusting portion 10a.
Flow path, that is, the reservoir chamber R3 of the rod-side chamber R1
A flow path that enables communication with the.

Incidentally, the magnetic member 23 has a flange portion 23b extending horizontally on the outer periphery of the upper end thereof.
The b also has a kerf 23c communicating with the kerf 23a.

Further, the upper end of the magnetic member 23, that is, the upper end on the inner peripheral side of the collar portion 23b is in contact with the lower end of a shaft sealing member 15 which will be described above and which is arranged above.

By the way, the solenoid 20 is arranged so as to be interposed on the outer periphery of the magnetic member 23, and the cylindrical bobbin member 24 made of a non-magnetic material is housed in the cylindrical bobbin member 24. And the coil 25 that is disposed.

Further, at the upper end of the solenoid 20, that is, at the upper end of the cylindrical bobbin member 24, the upper end of the magnetic member 23 is fixed to the predetermined position of the seal member 21 by the lower end surface thereof. That is, the annular core member 26, which is positioned so as to be flush with the upper end of the collar portion 23b, is adjacently provided.

Incidentally, the lower end of the valve body 30 described later is seated on the upper end of the annular core member 26 and the upper end of the flange portion 23b.

Then, the annular core member 26 and the collar portion 2 are
A space (not shown) is formed between the return spring 3 and 3b, and a return spring 27, which is a leaf spring for urging a valve body 30 described later in an upward direction, is disposed in the space.

Therefore, in the solenoid 20, since the magnetic member 23 and the annular core member 26 are distributed when the solenoid 20 is excited, the valve body 30 is attracted to the solenoid 20 side. Further, since the return spring 27 is provided when the excitation is released, it is possible to promptly allow the detachment from the magnetic member 23 and the annular core member 26 of the valve body 30.

The valve body 30 is provided adjacent to the upper end of the solenoid 20 and moves so as to descend in the figure when the solenoid 20 is excited, and its lower end is seated on the upper ends of the magnetic member 23 and the annular core member 26. The shaft sealing member 15 described later is slidably interposed.

That is, the valve body 30 has a tubular portion 31 which is vertically movably interposed on the outer periphery of the shaft sealing member 15, and the tubular portion 31.
Is formed so as to have a flange portion 32 that extends horizontally on the outer periphery of the lower end of the cylindrical portion 31, and the stopper 33 and the annular core member that protrude horizontally in the outer periphery on the upper end side of the tubular portion 31. It is supposed that the spring 34, which is provided between the spring 26 and the spring 26, urges the spring 26 in the upward direction.

The valve body 30 has the flange portion 3
2 is a kerf 23 formed on the collar portion 23b of the magnetic member 23.
The cylindrical portion 3 has a kerf 32a communicating with a.
1 has a kerf 31a communicating with the kerf 32a.

Therefore, in the valve body 30, when the solenoid 20 is excited, it is lowered against the urging force of the spring 34 and its lower end is seated on the upper ends of the magnetic member 23 and the annular core member 26. In addition, when the excitation of the solenoid 20 is released, the lower end of the solenoid 34 is lifted by the urging force of the spring 34 and is separated from the upper ends of the magnetic member 23 and the annular core member 26.

The shaft sealing member 15 is made of a non-magnetic material,
The inner periphery of the cylinder 1 is formed so as to close the upper end of the cylinder 1 and to form a flow path that allows the rod-side chamber R1 and the reservoir chamber R3 to communicate with each other, and to allow the piston rod 2 to be inserted into the axial core portion. In addition, a bearing member 16 that slidably contacts the outer circumference of the piston rod 2 is provided.

The shaft sealing member 15 includes the bearing member 16, and the inner peripheral upper end of the seal 11c is arranged upward.
The annular plate 17 made of a non-magnetic material is arranged between the upper end on the outer peripheral side of the shaft sealing member 15 and the seal 11c.

Further, in the illustrated example, the shaft sealing member 15 is set so as to also function as a valve guide as described above. Therefore, the shaft sealing member 15 is cylindrically extended at the lower end on the outer peripheral side. The drooping part 15a
While fitting the upper end of the cylinder 1 on the inner circumference of a, the lower end side inner circumference of the cylindrical portion 31 and the inner circumference of the flange portion 32 of the valve body 30 are slidably contacted with the outer circumference of the hanging portion 15a.

The upper end of the magnetic member 23, that is, the upper end on the inner peripheral side of the collar portion 23b is in contact with the lower end of the hanging portion 15a.

By the way, the rod side chamber R1 and the reservoir chamber R
The flow passage that allows communication with the oil passage 3 is formed by an oil hole 15b radially opened in the hanging portion 15a so as to connect the inner peripheral side and the outer peripheral side of the hanging portion 15a, and the oil hole 15b. And an annular groove 15c formed so as to be open to the outer periphery of the hanging portion 15a while being communicated with each other.

The annular groove 15c is provided in the valve body 3
It is set so that when 0 is raised, it is placed in an open state, and when the valve body 30 is raised, it is placed in a closed state by its tubular portion 31.

When the annular groove 15c is opened by raising the valve body 30, the annular groove 15c communicates with the cut groove 31a formed in the cylindrical portion 31 of the valve body 30 and the cut groove 31a. Cut groove 3 formed on flange 32 of valve body 30
Of course, it will be connected to 2a.

Therefore, in the shaft sealing member 15, the structure of the flow path that enables the rod side chamber R1 and the reservoir chamber R3 to communicate with each other is extended in a cylindrical shape at the lower end on the outer peripheral side of the shaft sealing member 15. Oil hole 15b and annular groove 15c formed in the hanging portion 15a provided
Therefore, the structure is simplified, and it becomes possible to prevent the hydraulic fluid passing through the flow passage from causing an unnecessary flow passage resistance.

Therefore, in the hydraulic shock absorber according to this embodiment formed as described above, the damping force adjusting unit 10 includes predetermined components such as the solenoid 20 and the valve body 30 in the casing 11. Therefore, the damping force adjusting unit 10 is made into a cartridge.
It becomes possible to carry out the product test about the product separately from the product test of the shock absorber body.

Further, the damping force adjusting portion 10 in the form of a cartridge is connected to the shock absorber main body by connecting the open end of the casing 11 constituting the cartridge to the outer cylinder 5 constituting the shock absorber main body by welding or the like. Will be integrated.

At this time, since the upper end side of the cylinder 1 is largely fitted to the inner peripheral side of the solenoid 20 constituting the damping force adjusting section 10 via the magnetic member 23, the shock absorber main body Even if the damping force adjusting unit 10 is provided outside the upper end side, it is not necessary to unnecessarily increase the length of the entire hydraulic shock absorber.

In the hydraulic shock absorber according to this embodiment, when the damping force adjusting unit 10 deenergizes the solenoid 20 and the valve body 30 is raised, the rod-side chamber in the cylinder 1 is closed. The communication between R1 and the reservoir chamber R3 becomes possible.

At this time, during the compression side stroke in which the piston rod 2 is immersed in the cylinder 1, the piston portion 3 descends in the cylinder 1. At this time, the rod side chamber R
1 runs short of hydraulic oil from the piston side chamber R2 via a check valve 3b on the extension side provided in the piston portion 3, and excess hydraulic oil in the piston side chamber R2 also passes through the check valve 3b. It flows into the side chamber R1.

The surplus oil that has flowed into the rod-side chamber R1 from the piston-side chamber R2 flows out into the reservoir chamber R3 via the damping force adjusting section 10 in the so-called open state.

Further, from the inside of the cylinder 1 to the piston rod 2
The piston portion 2 rises in the cylinder 1 during the extension side stroke, in which the piston side chamber R
2 is replenished from the reservoir chamber R3 via the pressure side check valve 4a provided in the base valve portion 4, and excess hydraulic oil in the rod side chamber R1 is passed through the damping force adjusting portion 10. Out into the reservoir chamber R3.

Therefore, when the excitation of the solenoid 20 is released, the hydraulic oil from the rod side chamber R1 side is released through the damping force adjusting section 10 in any of the expansion strokes. It will flow out into the chamber R3, and at this time, the damping valves 3a, 4a on each side will be in an inoperative state, and the damping force adjusting section 10, that is, the low damping force set by the valve body 30 will be generated. Stop.

In the damping force adjusting section 10, when the solenoid 20 is excited, the valve body 30 descends to close the flow passage that connects the rod side chamber R1 and the reservoir chamber R3 (FIG. 2). reference).

Therefore, during the expansion side stroke in this case, the hydraulic oil in the rod side chamber R1 flows into the piston side chamber R2 via the expansion side damping valve 3a arranged in the piston portion 3, and During the pressure side stroke, the hydraulic oil in the piston side chamber R2 is disposed in the base valve portion 4 and the pressure side damping valve 4a.
Will flow into the reservoir chamber R3.

The damping valves 3a and 4a on each side are opened under a high cracking pressure to allow the working oil to flow, so that a high damping force is generated.

Therefore, in the hydraulic shock absorber according to the present invention, it is possible to increase the generated damping force by exciting the solenoid 20 when required. For example, the hydraulic shock absorber is mounted on a vehicle. In this case, it is possible to change to a high damping force generation state at the time of attitude control during sudden braking, sudden start or roll, while normally obtaining a low riding force to obtain a soft ride comfort. Therefore, the running stability of the vehicle can be improved.

FIG. 3 shows another embodiment of the damping force adjusting section 10. However, the damping force adjusting section 10 is partially different from the embodiment shown in FIG. Alone,
The basic structure is the same.

Therefore, in the following, only different parts of the configuration will be described.

First, in the solenoid 20 portion, the cylindrical magnetic member 23 adjacent to the outer periphery on the upper end side of the cylinder 1 is different from the case of the above-described embodiment in that the flange portion 23b (FIG. 2) is provided at the upper end. (See) is not provided.

However, the magnetic member 23 is not the groove 23a.
Of course, it must have

The upper end of the solenoid 20, that is, the upper end of the cylindrical bobbin member 24 forming the solenoid 20 on the inner peripheral side is hollowed to form a recess, and
The annular core member 26 arranged so that the seal member 21 is fixed to the upper end on the outer peripheral side of the solenoid 20 is formed to be thicker than that in the above-described embodiment.

Further, in the recess, the return spring 27 (FIG. 2) which is the leaf spring in the above-mentioned embodiment is formed.
Instead of the above, a return spring 28 composed of a coil spring is housed and biases the valve element 30 in the upward direction.

Next, in the valve body 30 portion, the valve body 3
0 is composed of a cylindrical slider 33 that slidably contacts the outer periphery of the shaft sealing member 15 so as to be vertically movable, and a ring seat 34 fitted to the outer periphery of the lower end of the cylindrical slider 33.

Incidentally, the upper end of the return spring 28 is in contact with the lower end of the ring seat 34 on the inner peripheral side.

On the lower end side of the cylindrical slider 33, a cut groove 33a which may communicate with an annular groove 15c formed in the shaft sealing member 15 is formed.

The cut groove 33a communicates with the annular groove 15c with a slight opening when the valve body 30 is lowered by a small stroke due to the excitation of the solenoid 20. It is set so that when it is greatly lowered by excitation to 20, the communication with the annular groove 15c is cut off.

In the illustrated example, the ring seat 34 is not formed with a kerf.

In the portion of the valve element 30, an annular plate 35 made of a non-magnetic material is arranged at the lower end on the outer peripheral side of the annular seat 34 so that the outer peripheral side is seated on the upper end surface of the annular core member 26. The inner circumference is present.

The lower end of a cylindrical guide 36 made of a non-magnetic material is in contact with the upper end on the outer peripheral side of the annular plate 35, and the upper end of the guide 36 is made of a non-magnetic leaf spring. The return spring 37 is in contact therewith.

The return spring 37 is sandwiched between the lower end of the cap portion 11b of the casing 11.

The outer circumference of the guide 36 is adjacent to the inner circumference of the main body 11a constituting the casing 11, and the ring seat 34 is present on the inner circumference side.

Therefore, in the portion of the valve body 30, the excitation of the solenoid 20 lowers the valve body 30, that is, the ring seat 34. However, when the magnetic force from the solenoid 20 is small, The descending amount of the ring seat 34 is limited by the annular plate 35 and is suppressed to a small stroke amount.

At this time, the cut groove 33a formed on the cylindrical slider 33 communicates with the annular groove 15c forming the flow path with a slight opening, and the cut groove 33a is relatively large to the annular groove 15c. Compared with the case of communicating by opening,
A large flow resistance is generated, and a slightly high damping force can be generated.

In the valve body 30, when the magnetic force from the solenoid 20 is large, the ring seat 34 descends with a stroke amount large enough to bend the annular plate 35. The cut groove 33a formed in the cylindrical slider 33 is not communicated with the annular groove 15c, and the flow path that allows the rod side chamber R1 and the reservoir chamber R3 to communicate with each other is closed. At the time of sliding of the piston portion 3 at, the high damping force is generated by the operation of the damping valves 3a and 4a.

In each of the embodiments shown in FIGS. 2 and 3, the damping force adjusting section 1 in the hydraulic shock absorber according to the present invention is used.
It is assumed that 0 is set so that a high damping force is generated when the solenoid 20 is excited, but instead, a high damping force is generated when the damping force adjusting unit 10 releases the excitation of the solenoid 20. Of course, it may be set as follows.

[0088]

As described above, according to the present invention, the damping force adjusting portion of the hydraulic shock absorber is made into a cartridge by housing the predetermined constituent parts in the casing which constitutes the damping force adjusting portion. Therefore, there is an advantage that it is possible to carry out a product test on the damping force adjusting portion made into a cartridge separately from the product test on the shock absorber body.

Further, the damping force adjusting portion made into a cartridge is so arranged that the upper end side of the cylinder is inserted deeply when it is connected to the shock absorber main body, so that it is connected to the shock absorber main body. However, there is an advantage that the entire length of the hydraulic shock absorber can be prevented from being unnecessarily increased.

Since the effective length of the cylinder constituting the shock absorber main body is not reduced, it is possible to generate damping force having a predetermined characteristic and adjust its height, which is optimal for mounting on a vehicle, for example. There are advantages.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a hydraulic shock absorber according to an embodiment of the present invention.

FIG. 2 is a partially enlarged vertical cross-sectional view showing an enlarged damping force adjusting portion in the hydraulic shock absorber shown in FIG.

FIG. 3 is a partially enlarged vertical sectional view showing a damping force adjusting portion according to another embodiment of the present invention, similar to FIG.

FIG. 4 is a vertical sectional view showing a hydraulic shock absorber as a conventional example.

[Explanation of symbols]

 1 Cylinder 2 Piston Rod 3 Piston Part 3a, 4a Damping Valve 4 Base Valve Part 5 Outer Cylinder 10 Damping Force Adjusting Part 11 Casing 15 Shaft Sealing Member 16 Bearing Member 20 Solenoid 23 Magnetic Member 30 Valve Body R1 Rod Side Chamber R2 Piston Side Chamber R3 Reservoir Room

Claims (1)

[Claims] 1. A piston portion, which is continuously provided at the tip of a piston rod that is inserted into and retractable from the cylinder and defines a rod side chamber and a piston side chamber inside the cylinder, is arranged outside the cylinder when sliding inside the cylinder. Excitation of the solenoid in the existing damping force adjusting unit selects whether or not communication with the reservoir chamber formed outside the cylinder of the rod side chamber via the damping force adjusting unit is selected. Hydraulic pressure formed so that a low damping force is generated in the adjusting part, while a high damping force is generated in the damping valve arranged in the piston part and the damping valve arranged in the base valve part inside the lower end of the cylinder. In the shock absorber,
The damping force adjusting portion includes a casing formed such that its open end is connected to the inner circumference of the upper end of an outer cylinder arranged outside the cylinder, and the damping end adjuster is housed inside the casing on the open end side and A solenoid having a magnetic member adjacent to it, a valve body that is vertically movable on the upper end side of the solenoid, and a bearing member adjacent to the inner circumference of the valve body while slidingly contacting the outer circumference of the valve body and the upper end of the cylinder. A shaft sealing member that closes the cylinder, and when the casing is connected to the outer cylinder, the upper end side of the cylinder is made to exist on the inner peripheral side of the solenoid and the valve body while the piston is attached to the shaft core of the shaft sealing member. It is set to insert the rod,
The shaft sealing member, the valve body, and the magnetic member are formed with a flow path that enables the rod side chamber to communicate with the reservoir chamber, and the flow path is formed so as to be closed when the valve body is at the lowest position. Hydraulic shock absorber characterized in that