JPH05231462A - Damping force regulating type hydraulic shock absorber - Google Patents

Abstract

PURPOSE:To heighten responsiveness by providing a guide cylinder at an oil passage for communicating oil chambers in a cylinder, then providing a spool for changing the opening area of an oil hole slidably in the guide cylinder, and further providing a pair of chambers on both end sides of the guide cylinder. CONSTITUTION:Without applying a current to an electromagnetic proportional solenoid 18, a spool 14 in a guide cylinder 11 is slidingly displaced by a spring 17 until coming in contact with a stopper 12, and an orifice hole 11C is opened large by the land 14A of the spool 14. According to the extension of a piston rod 5, pressure oil in oil chambers A, B flows through the orifice hole 11C of an oil passage 9, in the small resistance state, so that damping force is in the soft state. When the current value of the solenoid 18 is increased, a rod 18A is extended downward so as to press the spool 14 to move it downward against the spring 17. The opening area of the orifice hole 11C thereby becomes small to enable the medium setting of damping force. With the increase of the current value, pressure oil cannot flow through the orifice hole 11C, so that hard damping force can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force adjusting type hydraulic shock absorber which is preferably used to damp vibrations of a vehicle, and more particularly to a damping force adjusting actuator using an electromagnetic proportional solenoid. The present invention relates to a force adjustable hydraulic shock absorber.

[0002]

2. Description of the Related Art In general, a cylinder, a piston slidably inserted into the cylinder and defining two oil chambers in the cylinder, one end of which is fixed to the piston, and the other end of which is the cylinder. It comprises a piston rod projecting outward, an oil passage provided in the piston rod for communicating between the oil chambers, and a damping force adjusting mechanism for adjusting the damping force by changing the flow passage area of the oil passage. Damping force adjustable hydraulic shock absorbers are known.

In this type of hydraulic shock absorber, for example, an orifice cylinder is provided in the piston rod located in the middle of the oil passage, and a shutter rotatably provided in the orifice cylinder is rotated by a rotary actuator or the like. As a result, a shutter rotation type damping force adjusting mechanism is used in which the orifice of the orifice cylinder is opened and closed to adjust the damping force.

As another conventional technique, for example, a poppet valve is provided and an actuator such as a solenoid drives the poppet valve in the axial direction of the piston rod.
There is also known a poppet valve-type damping force adjusting mechanism that adjusts the damping force by opening and closing the poppet valve.

[0005]

By the way, in the prior art using the above-described shutter rotation type damping force adjusting mechanism,
When the shutter provided in the orifice cylinder is rotated by the rotary actuator, a large sliding resistance is generated, and there is a problem that the responsiveness at the time of adjusting the damping force cannot be improved.

On the other hand, in another conventional technique using a poppet valve type damping force adjusting mechanism, since the poppet valve is axially driven by an actuator such as a solenoid,
The responsiveness when opening and closing the poppet valve can be improved. However, in this case, since the hydraulic pressure in the cylinder directly acts on the poppet valve from the axial direction, it is necessary to enlarge the actuator such as the solenoid in order to open and close the poppet valve against the hydraulic pressure. In addition, there is a problem that the poppet valve cannot be moved to an arbitrary axial position to continuously adjust the damping force.

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention is a damping force adjustable hydraulic buffer capable of continuously adjusting the damping force generated when the piston rod expands and contracts with high responsiveness. The purpose is to provide a vessel.

[0008]

In order to solve the above-mentioned problems, the present invention is characterized in that a damping force adjusting mechanism is provided on a piston rod in an axially extending manner, and a part of an oil passage is provided. A cylindrical guide tube having an oil hole bored in the radial direction to form a groove, a spool slidably provided in the guide tube in the axial direction to change the opening area of the oil hole, and the spool. In order to prevent pressure from acting in the axial direction, a pair of chambers located at both ends of the guide cylinder and separated from the oil chambers and the oil passages are provided on one side of the spool. An urging means for constantly urging the spool toward the other side in the axial direction, and an arbitrary axial direction of the spool against the urging means provided on the piston rod in response to an electric signal supplied from the outside. Actuator that adjusts the damping force by pushing it to the position Consisting of.

In this case, the actuator is composed of an electromagnetic proportional solenoid that expands and contracts the rod according to an electric signal supplied from the outside of the piston rod, and the rod of the electromagnetic proportional solenoid pushes the spool at its tip side. It is preferable to provide the spring means so that the tip of the rod is always in contact with the spool.

[0010]

With the above structure, the hydraulic pressure in the cylinder can be prevented from directly acting on the spool in the guide cylinder from the axial direction, and the spool in the guide cylinder can be smoothly pushed to any desired axial position by the actuator. it can.

Therefore, if the actuator is constituted by an electromagnetic proportional solenoid or the like, the opening area of the oil hole formed in the guide cylinder can be continuously changed when the spool is axially pushed in the guide cylinder. The damping force can be continuously adjusted according to the opening area.

Further, if the rod of the electromagnetic proportional solenoid is biased by the spring means so that the rod always contacts the spool, the rod always contacts the spool, so that the response of the operation by the electromagnetic proportional solenoid is improved. Is possible.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

1 and 2 show a first embodiment of the present invention.

In the figure, 1 is a cylindrical cylinder, 2 is a piston slidably fitted in the cylinder 1, and the piston 2 defines the inside of the cylinder 1 into two oil chambers A and B. is doing. Further, the piston 2 is provided with a damping-side damping force valve 3 and an extension-side damping force valve 4 via an auxiliary rod 7, which will be described later, and the damping force valves 3 and 4 are provided with oil holes 2A, A predetermined damping force is generated via 2A ,.

Reference numeral 5 denotes a piston rod inserted in the cylinder 1, and the piston rod 5 is a long main rod 6
And a stepped cylindrical auxiliary rod 7 screwed to the lower end of the main rod 6, to which the piston 2 and damping force valves 3 and 4 are fixed via a nut 8. There is. Here, the main rod 6 is provided with a rod insertion hole 6A and a valve accommodating hole 6B that is located below the rod insertion hole 6A and has a large diameter, and is provided at the lower end side of the valve accommodating hole 6B. The upper end side of the auxiliary rod 7 is screwed on. Further, the main rod 6 is provided with radial oil holes 6C, 6C, ... Which allow the oil chamber A to communicate with the inside of the valve accommodating hole 6B at all times.

On the other hand, the auxiliary rod 7 has a shaft hole 7A extending in the axial direction, and the shaft hole 7A is located on the upper end side of the shaft hole 7A.
Is formed in the upper end of the auxiliary rod 7 so as to communicate with the valve accommodating hole 6B of the main rod 6. Then, the shaft hole 7A of the auxiliary rod 7,
Each oil groove 7B, together with the valve housing hole 6B of the main rod 6, each oil hole 6C, a guide cylinder 11 described later, and the like, constitutes an oil passage 9 for communicating between the oil chambers A and B.

Reference numeral 10 denotes a damping force adjusting valve which constitutes the main body of the damping force adjusting mechanism, 11 denotes a guide cylinder which constitutes the valve casing of the adjusting valve 10, and the guide cylinder 11 is formed in a stepped cylindrical shape, Annular protrusions 11A and 11B are provided on the outer periphery of the upper side so as to be spaced apart in the axial direction. The guide cylinder 11 is fitted into the valve accommodating hole 6B of the main rod 6 via the annular projections 11A and 11B, and the annular stopper 12 is formed.
And the auxiliary rod 7 are positioned in the main rod 6. Further, the guide cylinder 11 has annular projections 11A, 11
Orifice holes 11C, 11C, ... As oil holes, which are located between B and B and are always in communication with the oil holes 6C of the main rod 6, are bored in the radial direction, and below the annular convex portion 11B. Other oil holes 11D, 11D, ... Are bored in the radial direction at a predetermined distance from each of the orifice holes 11C.

An annular passage 13 is located below the annular convex portion 11B between the guide cylinder 11 and the valve accommodating hole 6B.
Is formed, and the annular passage 13 has oil holes 11D and oil grooves 7
Always communicating with B, each orifice hole 11C and each oil hole 1
It constitutes a part of the oil passage 9 together with 1D. Also,
On the lower surface side of the stopper 12, oil grooves 12A which are in constant communication with the rod insertion hole 6A of the main rod 6 are radially formed.

Reference numeral 14 denotes a spool which is slidably fitted in the guide cylinder 11 and constitutes the damping force adjusting valve 10 together with the guide cylinder 11, and lands 14A and 14B are formed on the outer peripheral side of the spool 14 so as to project therefrom. The land 14A, 1
4B is each orifice hole 11C of the guide cylinder 11 and each oil hole 1
1D, they are separated from each other by a predetermined dimension in the axial direction.
Further, the spool 14 has an axial hole 14C that always communicates with a later-described spring chamber 16A, and a radial hole that communicates with the upper end side of the axial hole 14C and opens into an annular outer peripheral groove 14D above the land 14A. 14E is formed, and a chamber 16B described later, which is formed by the outer peripheral groove 14D, is formed in each oil groove 1 of the stopper 12.
It is in constant communication with the rod insertion hole 6A via 2A. The spool 14 is an electromagnetic proportional solenoid 1 described later.
When slidingly displaced in the axial direction in the guide cylinder 11 by the eight rods 18A, the opening area of each orifice hole 11C is changed by the land 14A to adjust the damping force.

Reference numeral 15 denotes a lid body which is screwed to the inner periphery of the lower end side of the guide cylinder 11 and closes the lower end side of the guide cylinder 11, and the lid body 15 is provided with oil pressure from the oil chamber B and the oil passage 9. The lower end of the spool 14 in the guide cylinder 11 is prevented from acting in the axial direction, and this pressure oil is passed through the oil grooves 7B to form the annular passage 13.
And it circulates toward each oil hole 11D. Here, the lid 15 forms a spring chamber 16A between the lower end side of the guide cylinder 11 and the spool 14, and a spring 17 as an urging means is arranged in the spring chamber 16A. The spring 17 always biases the spool 14 upward,
Each land hole 11 is formed by the land 14A of the spool 14.
It is designed to open C greatly.

On the other hand, on the upper end side of the guide cylinder 11, the other chamber 16 is located between the outer peripheral groove 14D of the spool 14 and the stopper 12 and constitutes a pair of chambers together with the spring chamber 16A.
B is formed. The chamber 16B is separated from the oil chamber A and the oil passage 9 and prevents pressure oil from the oil chamber A and the oil passage 9 from acting on the spool 14 in the guide cylinder 11 in the axial direction.

Reference numeral 18 denotes an electromagnetic proportional solenoid as an actuator for slidingly displacing the spool 14 in the guide cylinder 11 in the axial direction. The rod 18A of the electromagnetic proportional solenoid 18 is inserted into the rod insertion hole 6A of the main rod 6. ,
Above the rod insertion hole 6A, a coil portion (not shown) of the electromagnetic proportional solenoid 18 is disposed inside the main rod 6, and the like. Then, the electromagnetic proportional solenoid 18 outputs an electric signal from the outside of the piston rod 5 to the coil portion,
For example, by supplying a current signal, the rod 18A is expanded and contracted downward in proportion to the current value, and the spool 14 is pushed axially against the spring 17 at the tip (lower end) side of the rod 18A. To do.

Reference numeral 19 denotes a check valve provided on the lid body 15. The check valve 19 opens when the pressure inside the spring chamber 16A becomes higher than that on the oil chamber B side, and inside the spring chamber 16A. The oil liquid is circulated into the shaft hole 7A while blocking the reverse flow. Further, reference numeral 20 denotes another check valve provided on the main rod 6, and the check valve 20 opens when the inside of the rod insertion hole 6A or the like becomes higher in pressure than the oil chamber A side,
The oil liquid in the rod insertion hole 6A or the like is circulated toward the oil chamber A to prevent the reverse flow. In addition,
The chambers 16A and 16B are formed in the axial hole 14 of the spool 14.
C, because it is always communicating through the radial hole 14E,
Both check valves 19 and 20 are not necessarily required, and at least one check valve 19 (20) can compensate for smooth sliding displacement of the spool 14 in the guide cylinder 11.

The damping force adjusting type hydraulic shock absorber according to the present embodiment has the above-mentioned structure, and its operation will be described below.

First, without applying a current to the electromagnetic proportional solenoid 18, the spool 14 in the guide cylinder 11 is slid upward by the spring 17 to a position where it abuts against the stopper 12 as shown in FIG. When the orifice holes 11C are largely opened by the land 14A (normally open), the pressure oil in the oil chambers A and B forms the orifice holes 11C forming part of the oil passage 9 in accordance with the expansion and contraction of the piston rod 5. Since the fluid flows in a state where the resistance is relatively small, the damping force generated at this time is in a soft state in which the rising characteristics are relatively small as shown by the characteristic lines 21 and 22 in FIG. Then, when the sliding speed of the piston 2 increases in this state, the damping force valve 3 opens on the reduction side and a damping force characteristic corresponding to the piston speed is obtained as indicated by the characteristic line 21, and on the extension side the damping force valve 3 is obtained. 4 opens and characteristic line 2
Damping force characteristics such as 2 are obtained.

Next, when the value of the current applied to the electromagnetic proportional solenoid 18 is gradually increased, the rod 18A extends downward, and the spool 14 in the guide cylinder 11 springs the spool 17.
Since it is pushed downward against the above, the opening area of each orifice hole 11C is continuously reduced by the land 14A of the spool 14. When this opening area is reduced from the state shown in FIG. 1 to about half, the pressure oil flowing between the oil chambers A and B in accordance with the expansion and contraction of the piston rod 5 causes a gap between each orifice hole 11C and the land 14A. As shown by the characteristic lines 23 and 24 in FIG. 2, it is possible to generate a damping force having a relatively large rising characteristic on the contracting side and the expanding side of the piston rod 5, respectively. The damping force at this time is set to an intermediate medium state. Can be set.

Further, when the current value applied to the electromagnetic proportional solenoid 18 is increased and, for example, the rod 18A is extended to the maximum stroke position, each orifice hole 11C is substantially closed by the land 14A of the spool 14. Therefore, when the piston rod 5 expands and contracts, the pressure oil in the oil chambers A and B cannot substantially flow through the orifice holes 11C and the like, and the damping force at this time is the characteristic line 2 shown in FIG.
5 and 26, with a large rising characteristic, the sliding speed of the piston 2 increases and the damping force valve 3 increases.
When the valve 4 is opened, a predetermined damping force is generated, and a hard damping force characteristic can be obtained.

Thus, according to this embodiment, the damping force adjusting valve 10 is provided with the guide cylinder 11, the stopper 12, and the spool 1.
4, lid 15, chambers 16A, 16B and spring 17
In order to change the opening area of each orifice hole 11C formed in the guide cylinder 11 in the radial direction by the land 14A of the spool 14, the spool 14 is connected to the spring 17 by the rod 18A of the electromagnetic proportional solenoid 18. While pushing in the axial direction against the pressure, the both ends of the guide cylinder 11 form chambers 16A and 16B, and the pressure oil in the oil chambers A and B and the oil passage 9 is axially transferred to the spool 14 in the guide cylinder 11. Since it is configured to prevent the action from the direction, the following action and effects are obtained.

That is, for example, when the pressure in the oil chamber B becomes high during the contraction stroke of the piston rod 6 and this pressure oil flows through the shaft hole 7A of the auxiliary rod 7 toward the oil chamber A,
This pressure oil is guided in the radial direction from the oil holes 11D into the guide cylinder 11 by the lid 15 via the oil grooves 7B, the annular passage 13 and the like.
14B and the like, the oil flows into the oil chamber A from each orifice hole 11C through each oil hole 6C while the spool 14 in the guide cylinder 11 is actuated by the pressure oil. It is possible to reliably prevent sliding displacement in the direction.

Therefore, in this embodiment, the spool 1 in the guide cylinder 11 is driven by the rod 18A of the electromagnetic proportional solenoid 18.
4 can be smoothly slid in the axial direction only against the spring 17, and the responsiveness at the time of adjusting the damping force can be greatly improved. The expansion / contraction amount of the rod 18A of the electromagnetic proportional solenoid 18 continuously changes according to the current value of the electric signal applied from the outside, so that the land 14 of the spool 14
The opening area of each orifice hole 11C can be continuously changed by A, and the damping force characteristics at the time of contraction and extension of the piston rod 5 are in the range of characteristic lines 21 and 25 illustrated in FIG.
It can be continuously adjusted within the range of the characteristic lines 22 and 26.

Further, since the opening area of each orifice hole 11C is continuously changed, each orifice hole 11C is not suddenly blocked, and each orifice hole 1
When 1C is blocked by the land 14A of the spool 14,
It is possible to effectively prevent the generation of abnormal noise due to the action of an oil hammer or the like. Further, a non-return valve 19 is provided on the lid body 15, and the main rod 6
Since the check valve 20 is provided in the spring, the displacement of the spool 14 is not obstructed by the oil liquid in the spring chamber 16 and the spool 14 is smoothly slid by the rod 18A of the electromagnetic proportional solenoid 18 and the like. Various effects are exhibited such that the electromagnetic proportional solenoid 18 and the like can be displaced and the size can be reduced as much as possible.

Next, FIG. 3 shows a second embodiment of the present invention. The feature of this embodiment is that the damping force adjusting valve is housed in the auxiliary rod which constitutes a part of the piston rod. It is in. In this embodiment, the same components as those in the first embodiment shown in FIG. 1 described above are designated by the same reference numerals and the description thereof will be omitted.

In the figure, reference numeral 31 designates a piston rod. The piston rod 31 is composed of a main rod 32 and an auxiliary rod 33, which are similar to the piston rod 31 described in the first embodiment. The rod 33 is relatively long. The auxiliary rod 33 has a shaft hole 33A, and the piston 2 and the damping force valves 3, 4 are provided.
Etc. are fixed to the stepped portion 33B via the nut 8 and a small diameter tubular portion 33C, and the stepped portion 33 is provided on the upper end side of the small diameter tubular portion 33C.
It is integrally formed via B, and the upper end side is composed of a large-diameter cylindrical portion 33D screwed to the outer circumference of the lower end side of the main rod 32.

Also, the large diameter cylindrical portion 33D of the auxiliary rod 33.
A valve housing hole 33E for the damping force adjusting valve 10 is formed therein, and the valve housing hole 33E communicates with a rod insertion hole 32A in the main rod 32. The large-diameter cylindrical portion 33D has oil holes 33F, 33F, which communicate with the inside of the oil chamber A,
Are bored in the radial direction, and each of the oil holes 33F constitutes an oil passage 34 for communicating between the oil chambers A and B through the damping force adjusting valve 10 together with the shaft hole 33A and the like.

Reference numeral 35 denotes a guide cylinder which constitutes the valve casing of the damping force adjusting valve 10. The guide cylinder 35 is substantially the same as the guide cylinder 11 described in the first embodiment and has annular projections 35A and 35B. Although the guide cylinder 35 has the orifice holes 35C and the oil holes 35D, oil grooves 35E, 35E, ... Are radially formed on the lower end side of the guide cylinder 35, and the guide cylinder 35 has an axial direction corresponding to the depth dimension of the oil grooves 35E. The dimensions are long. Further, the guide cylinder 35 forms an annular passage 36 between it and the valve accommodating hole 33E, and the annular passage 36 communicates with each oil hole 35D at the upper end side and also has an axial hole through each oil groove 35E at the lower end side. It communicates with 33A.

Thus, also in this embodiment having such a configuration, the spool 14 provided in the guide cylinder 35 is resisted against the spring 17 and the rod 18A of the electromagnetic proportional solenoid 18 is provided.
By pushing in the axial direction with, the damping force can be continuously adjusted, and substantially the same action and effect as in the first embodiment can be obtained.

Next, FIG. 4 shows a third embodiment of the present invention, which is characterized in that an extra load is applied to an electromagnetic proportional solenoid as an actuator by the action of gas pressure or the like enclosed in a cylinder. In order to prevent the constant operation of the valve, spring means for canceling the gas charging pressure is provided on the rod tip side of the electromagnetic proportional solenoid. In this embodiment, the same components as those of the first embodiment are designated by the same reference numerals,
The description will be omitted.

In the figure, reference numeral 41 denotes a main rod which constitutes the piston rod 5 together with the auxiliary rod 7. The main rod 41 is formed in substantially the same manner as the main rod 6 described in the first embodiment, and has a rod insertion hole 41A. Although the valve accommodating hole 41B and each oil hole 41C are provided, a seal groove 41D is formed in the main rod 41 in the middle of the rod insertion hole 41A,
The valve housing hole 41B is formed relatively long.

Reference numeral 42 denotes a guide cylinder provided in the valve accommodating hole 41B of the main rod 41 via the stopper 12, and the guide cylinder 42 is formed in substantially the same manner as the guide cylinder 11 described in the first embodiment. The guide cylinder 42 has the annular protrusions 42A, 42B, the orifice holes 42C as oil holes, the other oil holes 42D, etc.
The annular convex portion 42A side is formed to extend relatively long in the axial direction to accommodate the above.

Reference numeral 43 indicates an electromagnetic proportional solenoid as an actuator for slidingly displacing the spool 14 in the guide cylinder 42 in the axial direction. The electromagnetic proportional solenoid 43 is substantially the same as the electromagnetic proportional solenoid 18 described in the first embodiment. However, in the electromagnetic proportional solenoid 43, a spring receiving portion 43B is integrally provided on the tip end side of the rod 43A. The spring receiving portion 43B is arranged in the guide cylinder 42 and is constantly pressed against the upper end surface of the spool 14 by the spring 44.

Reference numeral 44 denotes a spring which is located in the guide cylinder 42 and is arranged between the spring receiving portion 43B of the electromagnetic proportional solenoid 43 and the stopper 12 as a spring means.
Always biases the rod 43A of the electromagnetic proportional solenoid 43 downward, so that the gas filling pressure in the cylinder 1 that always acts upward on the rod 43A is offset by its spring force.

Further, 45 is a seal groove 4 of the main rod 41.
1D shows an O-ring mounted in the 1D, the O-ring 45 slidingly contacting the outer circumference of the rod 43A of the electromagnetic proportional solenoid 43,
The pressure oil (oil liquid) in the cylinder 1 is prevented from leaking outside from the rod insertion hole 41A.

Thus, in this embodiment having the above-mentioned structure, it is possible to obtain substantially the same effects as the first embodiment, but especially in this embodiment, the gas charging pressure in the cylinder 1 is electromagnetic. Since the action of the rod 43A of the proportional solenoid 43 is canceled by the spring 44, it is possible to prevent an excessive load from acting on the electromagnetic proportional solenoid 43, and to reduce the electromagnetic force to be generated by the electromagnetic proportional solenoid 43. It becomes possible.

Next, FIG. 5 shows a fourth embodiment of the present invention. The feature of this embodiment is that spring means is provided in the casing of the actuator for adjusting the damping force so that the gas charging pressure in the cylinder is the actuator. It is configured to prevent the action of the rod from being applied by the urging force of the spring means. In this embodiment, the same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the figure, reference numeral 51 denotes an electromagnetic proportional solenoid as an actuator provided on the projecting end of the main rod 6, which is fitted and fixed to the projecting end of the main rod 6 via a boss portion 52A. A bottomed cylindrical case 52, a coil portion 53 disposed in the case 52 for generating an electromagnetic force proportional to a current value of an electric signal supplied from the outside, and a radial direction of the coil portion 53. A movable shaft 54, which is provided inside the case 52 and is driven in the axial direction by the electromagnetic force from the coil portion 53, contacts the lower end side of the movable shaft 54 with its upper end side. In order to push the spool 14 in the axial direction based on the displacement, the lower end side of the rod 55 inserted into the rod insertion hole 6A and the case 52
And a cover 56 whose upper end is covered, and a flange-shaped spring receiving portion 54A is provided on the upper end of the movable shaft 54.

Reference numeral 57 denotes a spring which is disposed between the spring receiving portion 54A of the movable shaft 54 and the cover 56 and which constantly urges the rod 55 downward. The spring 57 is the tip side of the rod 55. A predetermined spring load is set so as to cancel out the gas charging pressure in the cylinder 1 that acts on the electromagnetic force so that the electromagnetic force generated from the coil portion 53 of the electromagnetic proportional solenoid 51 can be minimized.

Further, 58 denotes an O-ring for sealing between the rod insertion hole 6A of the main rod 6 and the rod 55,
The O-ring 58 is in sliding contact with the outer circumference of the rod 55 and prevents the pressure oil (oil liquid) in the cylinder 1 from leaking to the outside from the rod insertion hole 6A.

Thus, in this embodiment having the above-described structure, it is possible to obtain substantially the same effects as those of the third embodiment, but especially in this embodiment, the case 52 of the electromagnetic proportional solenoid 51 is provided. The spring bearing 5 of the movable shaft 54 located
Since the spring 57 is arranged between the 4A and the cover 56, the lower end side of the movable shaft 54 can be always brought into contact with the upper end of the rod 54 by the spring 57, and a gap is generated between the two, so that the responsiveness is improved. Can be prevented from deteriorating.

That is, when the movable shaft 54 is driven upward in the opposite direction while the movable shaft 54 is pressed downward by the electromagnetic force from the coil portion 53, the rod 55 is moved by the O-ring 58. Because sliding resistance works,
A gap is likely to be formed between the movable shaft 54 and the rod 55. However, since the movable shaft 54 is always urged downward by the spring 57, it is possible to prevent a gap from being generated between the movable shaft 54 and the movable shaft 54, and the rod 55 is made to follow the movable shaft 54 to be slidably displaced with high responsiveness. You can This is the same whether the hydraulic shock absorber is used upright so that the electromagnetic proportional solenoid 51 is on the upper side, or when it is used upside down.

In each of the above embodiments, the rod 18A (43A, 5) of the electromagnetic proportional solenoid 18 (43, 51) is used.
5) and the spool 14 are described as being formed separately, but instead of this, the spool 14 is integrally provided on the lower end side of the rod 18A (43A, 55), and both are integrally formed in the axial direction. It may be configured to be displaced.

Further, in each of the above-described embodiments, the spool 17 is always biased upward by the spring 17 provided in the spring chamber 16A, but instead of this, for example, compressed air is supplied into the spring chamber 16A. Encapsulation may be performed to constitute the urging means, and in this case, the axial hole 14C of the spool 14 and the check valve 19 of the lid 15 may be eliminated. Further, the biasing means may be configured by an elastic member such as rubber.

Furthermore, in each of the above embodiments, the electromagnetic proportional solenoid 18 (4
3, 51) is used as an example, the present invention is not limited to this. For example, an electric motor such as a stepping motor is used as an actuator to convert the rotary motion into a linear motion and the spool 14 in the axial direction. It may be pushed to.

Furthermore, in each of the above embodiments, the case where the damping force adjusting valve 10 is configured as a normally open type valve has been described as an example, but the present invention is not limited to this, and for example, a normally closed type valve. , And in this case, for example, the land 1 of the spool 14
Each oil hole 11D of the guide cylinder 11 (35, 42) by 4B
The land 14A, so as to block (35D, 42D)
Electromagnetic proportional solenoid 1
When the spool 14 is pushed downward against the spring 17 by the 8 (43, 51) rod 18A (43A, 55) or the like, the oil holes 11D (35D, 42D) are moved to the land 1 respectively.
4B may be used to gradually open the opening.

[0055]

As described in detail above, according to the present invention, a guide cylinder having an oil hole in the radial direction is provided in the piston rod, which is located in the middle of the oil passage for communicating the oil chambers in the cylinder. A spool for changing the opening area of the oil hole is provided in the guide cylinder so as to be slidable in the axial direction, and a pair of chambers is provided on both end sides of the guide cylinder to prevent pressure from acting on the spool in the axial direction. Since the actuator pushes the spool to an arbitrary position in the axial direction, the damping force can be adjusted with high responsiveness according to the sliding displacement of the spool, and the actuator and the like can be downsized. Further, by using an electromagnetic proportional solenoid or the like, it is possible to continuously adjust the damping force, and it is possible to effectively prevent generation of abnormal noise due to oil hammer.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of essential parts showing a damping force adjusting hydraulic shock absorber according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing damping force characteristics.

FIG. 3 is a longitudinal sectional view of an essential part showing a damping force adjustable hydraulic shock absorber according to a second embodiment.

FIG. 4 is a longitudinal sectional view of an essential part showing a damping force adjustable hydraulic shock absorber according to a third embodiment.

FIG. 5 is a longitudinal sectional view of essential parts showing a piston rod, an electromagnetic proportional solenoid and the like of a damping force adjusting hydraulic shock absorber according to a fourth embodiment.

[Explanation of symbols]

1 Cylinder 2 Piston 3,4 Damping Force Valve 5,31 Piston Rod 6,32,41 Main Rod 7,33 Auxiliary Rod 9,34 Oil Passage 10 Damping Force Adjusting Valve 11,35,42 Guide Tube 14 Spool 15 Lid 16A Spring chamber (chamber) 16B chamber 17 Spring (biasing means) 18, 43, 51 Electromagnetic proportional solenoid (actuator) 18A, 43A, 55 Rod A, B Oil chamber

Claims (2)

[Claims] 1. A cylinder, a piston slidably inserted into the cylinder, and defining the inside of the cylinder into two oil chambers, one end of which is fixed to the piston, and the other end of which is outside the cylinder. Damping force consisting of a protruding piston rod, an oil passage provided in the piston rod for communicating between the oil chambers, and a damping force adjusting mechanism for adjusting the damping force by changing the flow passage area of the oil passage. In the adjustable hydraulic shock absorber, the damping force adjusting mechanism is provided in the piston rod so as to extend in the axial direction, and has a cylindrical shape in which an oil hole is bored in a radial direction to form a part of the oil passage. A guide tube, a spool slidably provided in the guide tube in the axial direction and changing the opening area of the oil hole, and a guide tube for preventing the pressure from acting on the spool from the axial direction. Located on both ends, each of the oil chambers And a pair of chambers separated from the oil passage, a biasing means provided on one side of the spool for constantly biasing the spool toward the other side in the axial direction, and provided on the piston rod, and from the outside. A damping force adjusting hydraulic pressure, which comprises an actuator that adjusts the damping force by pushing the spool to an arbitrary position in the axial direction against the biasing means in response to an electric signal supplied. Shock absorber. 2. The actuator comprises an electromagnetic proportional solenoid that expands and contracts the rod in response to an electric signal supplied from the outside of the piston rod, and the rod of the electromagnetic proportional solenoid pushes the spool at its tip side. The damping force adjusting hydraulic shock absorber according to claim 1, wherein the damping force adjusting type hydraulic shock absorber is provided in the above-mentioned manner, and spring means is provided so that the tip of the rod is always in contact with the spool.