JP2007024195A - Damping force adjustable hydraulic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust dispersion of damping force with simple constitution in a damping force adjustable hydraulic shock absorber. <P>SOLUTION: The damping force adjustable hydraulic shock absorber 10 comprises a damping force adjusting valve 30 partitioning a back pressure chamber 32 allowed to communicate with a main passage 31 by a pilot passage 41, and opening/closing a valve seat 31S provided at the main passage 31; a spring receiver 37 sealing the back pressure chamber 32 of the damping force adjusting valve 30 and clamping a spring 36 between itself and the damping force adjusting valve 30 while being operable to adjust spring load from the outside; an orifice 40 provided in the spring receiver 37 to form a part of the pilot passage 41 which connects the main passage 31 to the back pressure chamber 32 of the damping force adjusting valve 30; and a proportional solenoid relief valve 50 interposed in a passage 51 which connects the back pressure chamber 32 to a reservoir 16 and controlling the relief pressure of oil flow from the back pressure chamber 32 to the reservoir 16 to regulate the back pressure of the damping force adjusting valve 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a damping force adjusting hydraulic shock absorber.

  As a hydraulic shock absorber used for a suspension device of an automobile or the like, there is a damping force adjustment type hydraulic shock absorber capable of appropriately adjusting a damping force in order to improve riding comfort and driving stability in accordance with road surface conditions, traveling conditions, and the like.

The hydraulic shock absorber of Patent Document 1 has a pilot type damping force adjustment valve, and adjusts the back pressure of the damping force adjustment valve with a pilot element.
JP-A-8-61417

  For hydraulic shock absorbers that use a pilot type damping force adjustment valve, variation in damping force due to the processing accuracy of the spring that applies the closing force to the damping force adjustment valve and the processing accuracy of the orifice that leads to the back pressure chamber of the damping force adjustment valve It is conceivable to provide a spring load adjusting means on the damping force adjusting valve. However, in the hydraulic shock absorber of Patent Document 1, a pilot element having a solenoid actuator or the like is arranged in series on the back side of the damping force adjustment valve. For this reason, the spring load adjusting means cannot be provided on the back side of the damping force adjusting valve, etc., and in order to adjust the variation in damping force by the damping force adjusting valve, the protrusion amount of the pilot element such as a solenoid actuator is adjusted. In addition, the solenoid actuator or the like becomes a dedicated part, resulting in high cost.

  An object of the present invention is to adjust variation in damping force with a simple configuration in a damping force adjusting hydraulic shock absorber.

  According to the first aspect of the present invention, a cylinder that contains oil, a piston rod that is inserted into the cylinder, a piston that is connected to the piston rod and defines a rod side chamber and a piston side chamber, and oil and gas are enclosed. In a damping force adjustment type hydraulic shock absorber having a reservoir to perform, a main passage that forms a one-way flow of oil from the rod side chamber to the reservoir, and an extension side allowable check that allows only the oil flow from the reservoir to the piston side chamber An extension side passage having a valve, a pressure side passage having a pressure side allowable check valve that allows only the flow of oil from the piston side to the rod side chamber, and a back pressure chamber that can be communicated by the main passage and the pilot passage are defined. In addition, the damping force adjustment valve that opens and closes the valve seat provided in the main passage and the back pressure chamber of the damping force adjustment valve are sealed, and a spring is sandwiched between the damping force adjustment valve and A spring receiver that enables an adjustment operation of the spring load, an orifice that is provided on the spring receiver and forms a part of a pilot passage that connects the main passage and the back pressure chamber of the damping force adjusting valve, and a passage that connects the back pressure chamber to the reservoir And a proportional solenoid type relief valve that adjusts the back pressure of the damping force adjusting valve by controlling the relief pressure of the oil flow from the back pressure chamber to the reservoir.

  According to a second aspect of the present invention, in addition to the first aspect of the present invention, the damping force adjusting valve and the proportional solenoid relief valve are juxtaposed with a valve housing.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the damping force adjusting valve is a spool valve, and the spool valve includes a disk valve that contacts and separates from a valve seat of the main passage.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, an extension-side relief valve is opened on the piston by a hydraulic pressure higher than a certain level in the rod-side chamber to flow the oil in the rod-side chamber to the piston-side chamber. A pressure relief valve is provided on the partition base provided on the bottom side of the cylinder so as to open the piston side chamber by a hydraulic pressure higher than a certain level and flow the oil in the piston side chamber to the reservoir.

(Claim 1)
(a) The spring bearing for the spring that pressurizes the damping force adjusting valve is a spring load adjusting means that can be operated from the outside. Thereby, it is possible to adjust the variation of the damping force due to the processing accuracy of the spring that applies the closing force to the damping force adjustment valve and the processing accuracy of the orifice connected to the back pressure chamber of the damping force adjustment valve with a simple configuration.

  (b) Since the orifice that forms part of the pilot passage that connects the main passage and the back pressure chamber of the damping force adjusting valve is provided in the spring receiver, the formation of the orifice is facilitated.

(Claim 2)
(c) Since the damping force adjusting valve and the proportional solenoid relief valve are juxtaposed to the valve housing, the spring bearing provided on the back side of the damping force adjusting valve can be used as a spring load adjusting means that can be easily operated from the outside.

(Claim 3)
(d) A spool valve constituting the damping force adjusting valve is provided with a disk valve that contacts and separates from the valve seat of the main passage. The disc valve bends at a constant pressure, opens the valve seat of the main passage even if the spool valve does not open, and generates a high damping force when the piston speed is high.

(Claim 4)
(e) An expansion relief valve is provided on the piston, a compression relief valve is provided on the partition base, and the valve opening pressure is set to be less than the breakdown pressure of the proportional solenoid relief valve. Can protect.

  1 is an overall cross-sectional view showing a hydraulic shock absorber, FIG. 2 is a cross-sectional view of an essential part of FIG. 1, FIG. 3 is a cross-sectional view showing a hydraulic circuit of the hydraulic shock absorber, and FIG. FIG. 5 is a cross-sectional view showing the flow when the back pressure chamber of the damping force adjusting valve is at a low pressure.

  As shown in FIG. 1, the hydraulic shock absorber 10 includes a cylinder 11 for containing oil, a piston rod 12 inserted into the cylinder 11, a rod side chamber 14 </ b> A and a piston side chamber connected to the piston rod 12. And a piston 13 partitioning 14B. Further, the hydraulic shock absorber 10 is provided with an outer tube 15 on the outer periphery of the cylinder 11 via an annular gap, and forms a reservoir 16 that encloses oil and gas in the outer tube 15.

  In the hydraulic shock absorber 10, a cap 17 is attached to the upper end portion of the outer tube 15, and the rod guide 18 is sandwiched between the cap 17 and the upper end portion of the cylinder 11. The rod guide 18 seals the rod side chamber 14A and the reservoir 16, and includes an oil seal and a dust seal, and supports the piston rod 12 so as to be slidable.

  The hydraulic shock absorber 10 includes a main passage 31 that forms a one-way flow of oil from the rod-side chamber 14A to the reservoir 16, and an extension-side allowable check valve 21 that allows only the oil flow from the reservoir 16 to the piston-side chamber 14B. And a pressure side passage 24 having a pressure side allowable check valve 23 that allows only the flow of oil from the piston side chamber 14B to the rod side chamber 14A.

  The hydraulic shock absorber 10 defines a back pressure chamber 32 that can communicate with the main passage 31 and the pilot passage 41, and has a damping force adjustment valve 30 that opens and closes a valve seat 31 </ b> S provided in the main passage 31.

  The hydraulic shock absorber 10 seals the back pressure chamber 32 of the damping force adjustment valve 30, sandwiches a coiled valve spring 36 between the damping force adjustment valve 30, and can adjust the spring load from the outside. A spring receiver 37 is provided.

  The hydraulic shock absorber 10 is provided in a spring receiver 37 and has an orifice 40 that forms a part of a pilot passage 41 that connects the main passage 31 and the back pressure chamber 32 of the damping force adjusting valve 30.

  The hydraulic shock absorber 10 is interposed in a passage 51 that connects the back pressure chamber 32 to the reservoir 16, and controls the relief pressure of the oil flow from the back pressure chamber 32 to the reservoir 16 to control the back pressure of the damping force adjustment valve 30. A proportional solenoid relief valve 50 for adjustment is provided.

  Hereinafter, a specific configuration in which the hydraulic shock absorber 10 is provided with the extension-side allowable check valve 21, the pressure-side allowable check valve 23, the damping force adjustment valve 30, the orifice 40, and the proportional solenoid relief valve 50 will be described.

  2 and 3, the hydraulic shock absorber 10 has a bottom piece 61 seated on the bottom of the outer tube 15, and is located in the inner circumferential space at the lower end of the outer tube 15 (reservoir 16). The spacer tube 62 and the partition base 63 are sandwiched between the lower end of the spacer 11, and the inner and outer spaces of the spacer tube 62 are always conducted by the connecting path 61A provided in the bottom piece 61. Part of the reservoir 16. The outer tube 15 is divided into three parts: an upper outer tube 15A, an intermediate outer tube 15B, and a lower outer tube 15C. The lower outer tube 15C is constituted by a part of a valve housing 70 described later.

  The hydraulic shock absorber 10 is provided with a connecting tube 64 on the outer periphery of the cylinder 11 via a small annular gap, a separator 65 on the outer periphery of the lower end of the cylinder 11, and a main passage connected to the rod side chamber 14 </ b> A on the outer periphery of the cylinder 11. 31 is extended. That is, the hydraulic shock absorber 10 is provided with a connecting tube 64 and a separator 65 outside the cylinder 11, and the main passage 31 is formed on the outer periphery of the cylinder 11 surrounded by the connecting tube 64 and the separator 65. The connecting tube 64 is fitted to the lower outer periphery, the lower inner periphery of the separator 65 is fitted to the lower outer periphery of the cylinder 11 via the O-ring 66A, and the main passage 31 on the outer periphery of the cylinder 11 surrounded by the connecting tube 64 is separated into the separator. The main passage 31 on the outer periphery of the cylinder 11 communicated with the first main communication path 31A provided at a plurality of circumferential positions (for example, four positions) of 65 and surrounded by the separator 65 is disposed at a plurality of circumferential positions (for example, four positions) of the separator 65. To the first pilot communication path 41A provided in The upper end portion of the connecting tube 64 is fitted to the outer periphery of the rod guide 18, the lower end portion of the separator 65 is fitted to the outer periphery of the partition base 63, and the connecting tube 64 and the separator 65 are connected to the rod guide 18. It is sandwiched between the partition bases 63.

  When the reservoir 16 is formed by the outer tube 15 provided on the outer periphery of the cylinder 11, the hydraulic shock absorber 10 is provided with the separator 65 on the outer periphery of the cylinder 11, so that the reservoir 16 is moved to the upper and lower reservoirs 16 </ b> A and 16 </ b> B by the separator 65. The upper and lower reservoirs 16A and 16B can be communicated by a reservoir communication channel 72 provided in a valve housing 70 described later.

  In the hydraulic shock absorber 10, a valve housing 70 is fitted to the outer periphery of the cylinder 11 and the separator 65. The valve housing 70 is integrally formed with a bottomed cylindrical lower outer tube 15 </ b> C, and is arranged around the partition base 63, the spacer tube 62, and the bottom piece 61 connected to the cylinder 11 and the separator 65 as described above. While covering the tube 15C, the inner periphery of the lower outer tube 15C is fitted to the outer periphery of the separator 65 provided on the outer periphery of the cylinder 11 via O-rings 66B, 66C, 66D, and the upper end of the lower outer tube 15C is fitted to the intermediate outer While fitting to the outer periphery of the lower end of the tube 15B, the bottom piece 61 seated on the bottom of the lower outer tube 15C is brought into contact with the lower end of the spacer tube 62.

  The valve housing 70 includes a first housing 70A and a second housing 70B, which are integrally provided with a lower outer tube 15C, and includes a damping force adjusting valve 30, a main passage 31, a back pressure chamber 32, an orifice 40, a pilot passage 41, and a proportional ratio. A solenoid relief valve 50 is provided.

  The valve housing 70 (lower outer tube 15C) passes through the second main communication path 31B for the main passage 31 and the second pilot communication path 41B for the pilot passage 41 to the separator 65 on the inner periphery of the lower outer tube 15C. Open to the fitting surface. When the valve housing 70 (lower outer tube 15C) is fitted to the outer periphery of the separator 65 and the outer periphery of the lower end of the intermediate outer tube 15B, the first main communication passage 31A and the main passage 31 for the main passage 31 included in the separator 65 are provided. Each of the first pilot communication paths 41A, the second main communication path 31B for the main path 31 provided in the valve housing 70, and the second pilot communication paths 41B for the pilot path 41 are arranged on the outer periphery of the separator 65. And at least one of the inner peripheries of the valve housing 70 (lower outer tube 15C), in this embodiment, the annular passages 31C and 31D and the annular passages 41C and 41D that are continuously recessed on the entire circumference of both are connected.

  The valve housing 70 (lower outer tube 15C) includes an upper connection port 71A with the upper reservoir 16A, a lower connection port 71B with the lower reservoir 16B, and a reservoir communication channel 72 that connects the upper and lower connection ports 71A and 71B. Upper and lower connection ports 71A and 71B are provided to be opened on the upper and lower sides of the inner periphery of the lower outer tube 15C with respect to the fitting surface to the separator 65. When the valve housing 70 (lower outer tube 15C) is fitted to the outer periphery of the separator 65 and the outer periphery of the lower end of the intermediate outer tube 15B, the upper connection port 71A provided in the valve housing 70 is directly opened to the upper reservoir 16A for lower connection. The mouth 71B opens directly into the lower reservoir 16B.

  The hydraulic shock absorber 10 houses the damping force adjustment valve unit 30 </ b> A in the valve housing 70 and the relief valve unit 50 </ b> A in the valve housing 70.

  The damping force adjusting valve unit 30A forms a spool valve 33 that constitutes the damping force adjusting valve 30, a disk valve 34 that sits on a flat surface around the tip convex portion 33A of the spool valve 33, and a valve seat 31S of the main passage 31. A valve block 70C that forms the valve chamber 33B of the spool valve 33, the disk valve 34 contacts and separates from the valve seat 31S, and the spool valve 33 slides in the valve chamber 33B. The valve block 70C is fitted into the mounting hole 73A of the second housing 70B, and the valve block 70D is inserted into the mounting hole 73B of the second housing 70B via the O-ring 35A. The disk valve 34 is bent at a constant hydraulic pressure and is separated from the valve seat 31 </ b> S, and the main passage 31 communicates with the reservoir communication passage 72. When the second housing 70B incorporating the spool valve 33 and the valve blocks 70C and 70D is mounted on the mounting mating surface of the first housing 70A, the valve block 70C is held in contact with the mounting mating surface of the first housing 70A. The valve blocks 70C and 70D and the second housing 70B form a reservoir communication flow path 72 around the spool valve 33. The disk valve 34 of the spool valve 33 is seated on the valve seat 31S of the main passage 31, and the main passage 31 and the reservoir The communication channel 72 is partitioned. The spool valve 33 slides on the outer periphery of the bottomed cylinder into the valve chamber 33B of the valve block 70D and linearly strokes, and a coil spring-like valve spring 36 is loaded into the cylinder and is screwed into the second housing 70B. The valve spring 36 is pressurized by a receiving (adjusting bolt) 37 so that the spring load can be adjusted. A space in the cylinder of the spool valve 33 is a back pressure chamber 32, and a pilot passage 41 communicates therewith. The spring receiver 37 seals the back pressure chamber 32, clamps the valve spring 36 with the spool valve 33, and allows the spring load to be adjusted from the outside.

  The spring receiver 37 includes an adjusting operation portion 37A, a screw portion 37B, an O-ring loading portion 37C, and a spring receiving portion 37D, which are continuously provided in the axial direction, and an insertion hole 74 (coaxially arranged with the valve chamber 33B) of the second housing 70B. The screw portion 37B is screwed with respect to the second housing 70B by an external operation force applied to the adjustment operation portion 37A, and the O-ring loading portion 37C and the spring receiving portion 37D slide within the insertion hole 74. The O-ring loading unit 37 </ b> C includes an O-ring 74 </ b> A that is in sliding contact with the insertion hole 74. The spring receiver 37 has a pilot passage 41 that has an O-ring loading portion 37C having a smaller diameter than the spring receiving portion 37D and extends from the outer periphery of the O-ring loading portion 37C near the spring receiving portion 37D to the end surface of the spring receiving portion 37D. The pilot passage 41 provided in the valve housing 70 (70B) and the pilot passage 41 provided in the spring receiver 37 are connected to each other by an annular gap formed around the O-ring loading portion 37C in the insertion hole 74. A part of the provided pilot passage 41 forms an orifice 40 and opens into the back pressure chamber 32 of the damping force adjusting valve 30. The pressure in the main passage 31 is introduced into the back pressure chamber 32 by the orifice 40 (pilot passage 41).

  The damping force adjusting valve 30 has a closing force, which is the sum of the force exerted by the back pressure of the back pressure chamber 32 on the spool valve 33 and the spring load of the valve spring 36, and the hydraulic pressure of the main passage 31 (rod side chamber 14 </ b> A). It closes when it exceeds the opening force that is the force exerted on the. Here, the pressure receiving area where the back pressure of the back pressure chamber 32 reaches the spool valve 33 is larger than the pressure receiving area where the oil pressure of the main passage 31 reaches the spool valve 33. Thus, when the proportional solenoid relief valve 40 is closed and the back pressure in the back pressure chamber 32 becomes high, the spool valve 33 is reliably closed.

  The relief valve unit 50A is juxtaposed with the damping force adjusting valve unit 30A in the valve housing 70, and the valve box 52 of the proportional solenoid relief valve 50 is connected to the valve chamber 75 of the second housing 70B of the valve housing 70 (parallel to the valve chamber 33B). The valve box 52 is retained by the retaining ring 53 in the second housing 70B. The valve box 52 inserted into the valve chamber 75 is divided into the front and rear so as to cross the intermediate portion of the above-described passage 51 provided in the second housing 70B, and the passage allowing the passages 51 and 51 separated in the front and rear to be conductive. The valve seat 54 provided with 54A is provided. The proportional solenoid relief valve 50 allows the valve element 57 connected to the operating rod 56 of the solenoid actuator 55 to contact and separate from the valve seat 54 so that the passage 54A can be opened and closed, and the relief valve 50 determined by the set current of the solenoid actuator 55. When the pressure exceeding the relief pressure is applied to the valve body 57, the valve body 57 opens the passage 54 </ b> A and allows the passage 51 to conduct so that the pressure in the back pressure chamber 32 is blown to the reservoir 16. The relief pressure of the relief valve 50 and thus the back pressure of the back pressure chamber 32 are controlled by changing the set current of the solenoid actuator 55.

  The hydraulic shock absorber 10 is provided with a disk-shaped pressure-side allowable check valve 23 and a pressure-side passage 24 in the piston 13.

  The hydraulic shock absorber 10 includes an extension-side allowable check valve 21 and an extension-side passage 22 in a partition base 63 provided on the bottom side of the cylinder 11. The valve spring 21A is supported by a bolt 25 fastened to the partition base 63, and the extension side passage 22 is opened and closed by the disk-like extension side allowable check valve 21 backed up by the valve spring 21A.

  The hydraulic shock absorber 10 opens the piston 13 with a hydraulic pressure higher than a certain level in the rod side chamber 14A (hydraulic pressure less than the breaking pressure of the relief valve 50), and causes the oil in the rod side chamber 14A to flow to the piston side chamber 14B. Is provided. The extension side relief valve 81 opens and closes an extension side passage 81 </ b> A provided in the piston 13.

  The hydraulic shock absorber 10 is opened to the partition base 63 by a hydraulic pressure higher than a certain level in the piston side chamber 14B (hydraulic pressure less than the breaking pressure of the relief valve 50) to flow the oil in the piston side chamber 14B to the rod side chamber 14A. Is provided. The pressure side relief valve 82 opens and closes a pressure side passage 82 </ b> A provided in the partition base 63.

The hydraulic shock absorber 10 operates as follows.
As the hydraulic shock absorber 10 expands and contracts, the cylinder 11 and the piston rod 12 expand and contract relatively, and a suspension spring (not shown) expands and contracts.

  (1) The oil in the cylinder 11 is discharged from the rod side chamber 14 </ b> A to the main passage 31 and attempts to open the damping force adjustment valve 30.

  (2) The hydraulic pressure in the cylinder 11 is discharged from the rod side chamber 14A to the main passage 31, passes through the orifice 40 from the pilot passage 41 and reaches the back pressure chamber 32, and the back pressure in the back pressure chamber 32 is proportional solenoid relief. When the pressure exceeds the relief pressure set for the valve 50, the relief valve 50 opens. As a result, the back pressure in the back pressure chamber 32 is released to the reservoir 16 (reservoir communication flow path 72) to reduce the pressure, and the damping force adjustment valve 30 (spool valve 33) is opened (FIG. 4).

  Next, when the back pressure in the back pressure chamber 32 is released to the reservoir 16 (reservoir communication channel 72) and becomes lower than the relief pressure of the proportional solenoid relief valve 50, the relief valve 50 is closed. Thus, when the back pressure in the back pressure chamber 32 is increased by receiving the pressure in the main passage 31, the damping force adjusting valve 30 (spool valve 33) is closed (FIG. 5).

  When the piston speed is high, oil flowing out from the rod side chamber 14A to the main passage 31 and passing through the orifice 40 from the pilot passage 41 becomes high speed, and the throttle action of the orifice 40 works. The response of the damping force adjusting valve 30 (relief valve 33) becomes dull with a delay in the increase in pressure.

  (3) When the piston speed is high, even if the proportional solenoid relief valve 50 is opened and the spool valve 33 of the damping force adjusting valve 30 is closed, the disk valve 34 is caused by the high-pressure oil discharged from the rod side chamber 14A to the main passage 31. Opens and generates a high damping force.

  According to the above (2), the back pressure of the back pressure chamber 32 for controlling the opening / closing of the damping force adjusting valve 30 (spool valve 33) can be adjusted by setting the relief pressure of the proportional solenoid type relief valve 50, and consequently the damping force adjusting valve 30. The damping force generated by the (spool valve 33) can be adjusted. The expansion / contraction speed of the suspension spring is controlled by the expansion / contraction damping force.

According to the present embodiment, the following operational effects can be obtained.
(a) The spring receiver 37 for the valve spring 36 that pressurizes the damping force adjusting valve 30 is a spring load adjusting means that can be operated from the outside. Thereby, the variation of the damping force due to the processing accuracy of the valve spring 36 that applies the closing force to the damping force adjusting valve 30 and the processing accuracy of the orifice 40 connected to the back pressure chamber 32 of the damping force adjusting valve 30 is simplified. Can be adjusted.

  (b) Since the orifice 40 that forms a part of the pilot passage 41 that connects the main passage 31 and the back pressure chamber 32 of the damping force adjusting valve 30 is provided in the spring receiver 37, the formation of the orifice 40 is facilitated.

  (c) Since the damping force adjusting valve 30 and the proportional solenoid relief valve 50 are juxtaposed to the valve housing 70, the spring receiver 37 provided on the back side of the damping force adjusting valve 30 is used as a spring load adjusting means that can be easily operated from the outside. it can.

  (d) A spool valve 33 constituting the damping force adjusting valve 30 is provided with a disk valve 34 that contacts and separates from the valve seat 31S of the main passage 31. The disc valve 34 bends at a constant pressure, opens the valve seat 31S of the main passage 31 even when the spool valve 33 does not open and strokes, and generates a high damping force when the piston speed is high.

  (e) The piston 13 is provided with the expansion side relief valve 81, the partition base 63 is provided with the pressure side relief valve 82, and the valve opening pressure is set to be less than the breaking pressure of the proportional solenoid relief valve 50. The solenoid type relief valve 50 can be protected.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention.

FIG. 1 is an overall cross-sectional view showing a hydraulic shock absorber. FIG. 2 is a cross-sectional view of the main part of FIG. FIG. 3 is a sectional view showing a hydraulic circuit of the hydraulic shock absorber. FIG. 4 is a cross-sectional view showing a flow when the back pressure chamber of the damping force adjusting valve is at a high pressure. FIG. 5 is a cross-sectional view showing a flow when the back pressure chamber of the damping force adjusting valve is at a low pressure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hydraulic buffer 11 Cylinder 12 Piston rod 13 Piston 14A Rod side chamber 14B Piston side chamber 16 Reservoir 21 Extension side allowable check valve 22 Extension side passage 23 Pressure side allowable check valve 24 Pressure side passage 30 Damping force adjustment valve 31 Main passage 31S Valve seat 32 Back pressure chamber 33 Spool valve 34 Disc valve 40 Orifice 41 Pilot passage 50 Proportional solenoid type relief valve 51 Orifice 63 Partition base 81 Extension side relief valve 82 Pressure side relief valve

Claims (4)

Damping force having a cylinder that contains oil, a piston rod that is inserted into the cylinder, a piston that is connected to the piston rod and defines the rod-side chamber and the piston-side chamber inside the cylinder, and a reservoir that encloses oil and gas In the adjustable hydraulic shock absorber,
A main passage that forms a one-way flow of oil from the rod side chamber to the reservoir;
An extension side passage having an extension side allowable check valve that allows only the flow of oil from the reservoir to the piston side chamber;
A pressure side passage having a pressure side allowable check valve that allows only the flow of oil from the piston side to the rod side chamber;
A damping pressure adjusting valve that defines a back pressure chamber that can communicate with the main passage and the pilot passage, and that opens and closes a valve seat provided in the main passage;
A spring receiver that seals the back pressure chamber of the damping force adjustment valve, clamps the spring between the damping force adjustment valve, and adjusts the spring load from the outside; and
An orifice which is provided in the spring support and forms a part of a pilot passage connecting the main passage and the back pressure chamber of the damping force adjusting valve;
A proportional solenoid-type relief valve that is interposed in a passage connecting the back pressure chamber to the reservoir and controls the relief pressure of the oil flow from the back pressure chamber to the reservoir to adjust the back pressure of the damping force adjusting valve; A damping force adjustment type hydraulic shock absorber.   The damping force adjusting type hydraulic shock absorber according to claim 1, wherein the damping force adjusting valve and the proportional solenoid type relief valve are juxtaposed on a valve housing.   The damping force adjusting type hydraulic shock absorber according to claim 1 or 2, wherein the damping force adjusting valve is a spool valve, and the spool valve includes a disk valve that contacts and separates from a valve seat of the main passage. The piston is provided with an expansion-side relief valve that opens by the oil pressure of the rod-side chamber above a certain level and flows the oil in the rod-side chamber to the piston-side chamber,
4. The pressure relief valve according to claim 1, wherein a pressure relief valve is provided in the partition base provided on the bottom side of the cylinder to open the piston side chamber with a hydraulic pressure higher than a certain level and flow the oil in the piston side chamber to the reservoir. Damping force adjustable hydraulic shock absorber.

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