JPH1073141A - Damping force adjustable hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand the adjust range of a damping force characteristic and obtain a stable damping force characteristic in a damping force adjustable hydraulic shock absorber. SOLUTION: By moving a spool 68 in response to the flowing current to an actuator 28, the flow passage area of ports 60, 63 are changed and by directly changing the flow passage area between cylinder upper/lower chambers 2a, 2b, an orifice characteristic is adjusted and also as the valve characteristic is adjusted by changing the inner pressure of pilot rooms 58, 59 in response to the pressure loss and changing the valve opening pressure of disc valves 46, 47, the adjust range of the damping force characteristic can be expanded. The pilot chambers 58, 59 are constituted by the side walls of the valve member 26, 27, disc valves 46, 47, seal discs 54, 55 and seal members 28, 29 and as it has no slide part, the leak of an oil liquid is less and a stable damping force characteristic can be obtained and the dispersion of the damping force by a temperature change can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force-adjustable hydraulic shock absorber mounted on a suspension system of a vehicle such as an automobile.

[0002]

2. Description of the Related Art A hydraulic shock absorber mounted on a suspension system of a vehicle such as an automobile is provided with a damping force that can be appropriately adjusted in order to improve riding comfort and steering stability in accordance with road surface conditions, running conditions, and the like. There is a damping force adjustable hydraulic shock absorber.

[0003] In general, a damping force adjusting type hydraulic shock absorber slidably fits a piston having a piston rod connected to a cylinder filled with an oil liquid so as to divide the cylinder into two chambers.
A main oil passage and a bypass passage for communicating the two chambers in the cylinder with the piston portion, and a damping force generating mechanism comprising an orifice and a disc valve in the main oil passage,
The bypass passage is provided with a damping force adjusting valve for adjusting the flow passage area. A reservoir for compensating for a volume change in the cylinder due to expansion and contraction of the piston rod by compression and expansion of gas is connected to one chamber in the cylinder via a base valve.

Then, the bypass passage is opened by the damping force adjusting valve to reduce the flow resistance of the oil fluid between the two chambers in the cylinder to reduce the damping force, and the bypass passage is closed to reduce the flow between the two chambers. The damping force is increased by increasing the resistance. As described above, the damping force characteristic can be appropriately adjusted by opening and closing the damping force adjustment valve.

However, when the damping force is adjusted by changing the flow passage area of the bypass passage as described above, the damping force depends on the orifice area of the bypass passage in a low piston speed range. Although the characteristics can be changed greatly, in the middle and high speed range of the piston speed, the damping force depends on the damping force generation mechanism (disk valve etc.) of the main oil passage, so the damping force characteristics can be changed greatly. Can not.

Therefore, conventionally, for example, Japanese Utility Model Laid-Open No. Sho 62-155
As described in JP-A-242, a pressure chamber is formed at the back of a main valve which is a damping force generating mechanism of a main oil liquid passage provided in a piston portion, and this pressure chamber is connected to a main valve via a fixed orifice. And a cylinder chamber downstream of the main valve through a variable orifice has been proposed.

According to this damping force adjusting type hydraulic shock absorber, by opening and closing the variable orifice, the flow area between the two chambers in the cylinder is adjusted, and the pressure in the pressure chamber is changed to open the main valve. The valve initial pressure can be changed. In this manner, the orifice characteristics (the damping force is approximately proportional to the square of the piston speed) and the valve characteristics (the damping force is approximately proportional to the piston speed) can be adjusted, and the adjustment range of the damping force characteristics can be widened. can do.

[0008]

However, in the damping force adjusting type hydraulic shock absorber described in the above-mentioned publication, the pressure chamber is formed by slidably fitting the main valve to the valve guide. Leakage of the oil liquid occurs in the sliding portion between the guide and the main valve, so that it is difficult to obtain a stable damping force. In particular, since the leakage from the sliding portion is greatly affected by the change in viscosity due to the temperature of the oil liquid, the variation in the damping force due to the temperature change becomes large. Further, the machining of the sliding portion requires high machining accuracy, so that the manufacturing cost increases.

The present invention has been made in view of the above points, and an object of the present invention is to provide a damping force-adjustable hydraulic shock absorber that has a wide adjustment range of damping force characteristics and can obtain a stable damping force. Aim.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention according to claim 1 comprises: a cylinder filled with an oil liquid; a piston slidably fitted in the cylinder;
A piston rod having one end connected to the piston and the other end extending to the outside of the cylinder, a main passage for allowing an oil liquid to flow by sliding the piston, and a flow passage for the main passage provided in the main passage A main damping valve for adjusting an area, a pilot chamber provided on a back portion of a valve body of the main damping valve to apply an internal pressure in a valve closing direction of the valve body, and the main damping valve of the pilot chamber and the main passage An upstream passage communicating with the upstream of the main passage, a fixed orifice provided in the upstream passage, a downstream passage communicating the pilot chamber with the main passage downstream of the main damping valve, and A variable orifice provided in the side passage and comprising a variable orifice for adjusting the flow passage area of the downstream passage, wherein a bottomed cylindrical valve member and a bottom portion of the valve member are axially moved. A penetrating oil passage and the bottom An annular inner seal portion protruding on the inner peripheral side of the oil passage on the inner wall; an annular valve seat protruding on the outer peripheral side of the oil passage on the inner wall; and an annular protrusion protruding on the outer peripheral side of the valve seat on the inner wall. An outer seal portion, a groove portion that opens between the valve seat and the outer seal portion of the inner wall, a disk valve whose inner peripheral portion is fixed to the inner seal portion and whose outer peripheral portion abuts the valve seat, An annular seal disk having an inner peripheral portion abutting on a back surface portion of the disk valve and an outer peripheral portion abutting on the outer seal portion; spring means for pressing the seal disk against the disk valve and the outer seal portion; A sealing member fitted to the opening of the member, and the main passage is constituted by the oil passage and the groove,
The valve body of the main damping valve is constituted by the disk valve, and the pilot chamber is defined by the side wall of the valve member, the disk valve, the seal disk, and the seal member.

[0011] With this configuration, the damping force characteristic (orifice characteristic) is adjusted by directly changing the flow path area between the cylinder upper and lower chambers by changing the flow path area of the downstream passage by the variable orifice. With
The damping force characteristic (valve characteristic) is adjusted by changing the internal pressure of the pilot chamber according to the pressure loss caused by the variable orifice to change the valve opening characteristic of the damping valve. Further, since the pilot chamber is formed without providing the sliding portion, leakage of the oil liquid from the pilot chamber can be reduced. Further, since the inner seal portion, the valve seat, and the outer seal portion of the valve member can be integrally formed, an error in their protruding height can be reduced.

According to a second aspect of the present invention, in the configuration of the first aspect, the spring means is a disc-shaped leaf spring, and the leaf spring is formed by a disc valve, a seal disc, and the leaf spring. An oil passage is provided for communicating the closed space and the pilot chamber with each other.

With this configuration, the space formed by the disk valve, the seal disk, and the leaf spring and the pilot chamber communicate with each other through the oil passage and always have the same pressure. When is increased, the space is not crushed.

According to a third aspect of the present invention, there is provided the first or second aspect.
Is characterized in that a sub damping valve is provided which opens upon receiving the pressure of the oil liquid flowing to the fixed orifice and generates a damping force having valve characteristics in accordance with the opening degree.

With this configuration, a damping force having valve characteristics is generated by the sub damping valve before the main damping valve is opened.

The invention according to claim 4 is the invention according to claims 1 to 3 above.
In any one of the above structures, an annular projection is provided on the back surface of the disk valve along the circumferential direction thereof, and an inner peripheral portion of the seal disk is brought into contact with the projection.

[0017] With such a configuration, the seal disk abuts on the disk valve via the projection, so that even if the disk valve and the seal disk are bent due to an increase in the pressure in the pilot chamber, the disk valve and the seal disk are bent. The diameter of the contact portion with the disk is always constant.

The invention according to claim 5 is the invention according to claims 1 to 3.
In any of the above configurations, a disk-shaped retainer disk having a diameter slightly smaller than that of the disk valve is interposed between the disk valve and the seal disk, and the seal disk is provided near the outer peripheral end of the retainer disk. It is characterized in that the inner peripheral portion is brought into contact.

With this configuration, since the seal disk is in contact with the vicinity of the outer peripheral end of the retainer disk, even if the disk valve and the seal disk bend due to an increase in pressure in the pilot chamber,
The diameter of the contact portion between the seal disk and the retainer disk hardly changes.

[0020] The invention of claim 6 is the first to third aspects of the present invention.
In any one of the above configurations, a positioning projection that contacts the outer peripheral surface of the disk valve is formed on the outer peripheral portion, an annular first protrusion that contacts the disk valve is formed on one surface, and the other surface is formed. An annular seat member formed with a second protrusion contacting the seal disk is interposed between the disk valve and the seal disk.

According to this structure, the seat member abuts on the disc valve via the first protrusion, so that even if the disc valve and the seal disc are bent by the increase in the pressure in the pilot chamber, the seat member can be seated. The diameter of the contact portion between the member and the disc valve is always constant. Further, the pressure in the pilot chamber can be applied to a portion on the inner peripheral side from the inner peripheral end of the seal disk of the disk valve by the first protrusion of the seat member, and
When the disc valve is opened, the seat member moves in parallel along the axial direction, so that when the disc valve is opened, the outer peripheral portion of the disc valve comes into contact with the central portion of the seal disc to seal the seal disc to the outside. No lifting from the part.

Further, the invention of claim 7, in the construction of the claims 1 to 6, the ratio of d _b / d of the inner diameter d _b of the inner diameter d _a and the outer seal portion of the valve seat disk valve _a ≦ 1.
The feature is 2.

With this configuration, the pressure receiving area of the seal disk with respect to the pilot chamber can be appropriately reduced, and the pilot pressure acting on the disk valve can be optimized.

Embodiments of the present invention will be described below in detail with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the damping force-adjusting hydraulic shock absorber 1 has a double-cylinder structure in which an outer cylinder 3 is provided outside a cylinder 2. A reservoir chamber 4 is formed at the bottom. A piston 5 is slidably fitted in the cylinder 2, and the piston 5 defines the inside of the cylinder 2 into two chambers, a cylinder upper chamber 2a and a cylinder lower chamber 2b. One end of a piston rod 6 is connected to the piston 5 by a nut 7, and the other end of the piston rod 6 passes through the cylinder upper chamber 2 a and is mounted on the upper end of the cylinder 2 and the outer cylinder 3. And it is inserted into a seal member (not shown) and extends to the outside of the cylinder 2. At the lower end of the cylinder 2, a base valve 8 for partitioning the cylinder lower chamber 2 b and the reservoir chamber 4 is provided. An oil liquid is sealed in the cylinder 2, and an oil liquid and a gas are sealed in the reservoir chamber 4.

The piston 5 has an oil passage 9 communicating between the cylinder upper and lower chambers 2a and 2b, and a cylinder lower chamber 2b of the oil passage 9.
A check valve 10 is provided to allow the flow of the oil liquid from the side to the cylinder upper chamber 2a side. The base valve 8 is provided with an oil passage 11 for communicating the cylinder lower chamber 2b and the reservoir chamber 4 and a check for permitting the flow of the oil liquid from the reservoir chamber 4 side of the oil passage 11 to the cylinder lower chamber 2b. A valve 12 is provided.

A substantially cylindrical passage member 13 is fitted around the center of the cylinder 2. An upper tube 14 is fitted on the upper outer periphery of the cylinder 2 and connected to the passage member 13 to form an annular oil passage 15 with the cylinder 2. The annular oil passage 15 communicates with the cylinder upper chamber 2a via an oil passage 16 provided on a side wall near the upper end of the cylinder 2. A lower tube 17 is provided on the outer periphery of the lower part of the cylinder 2.
Are fitted and connected to the passage member 13, and the cylinder 2
To form an annular oil passage 18. The annular oil passage 18 communicates with the cylinder lower chamber 2b via an oil passage 19 provided on a side wall near the lower end of the cylinder 2. A connection plate 20 is attached to the outer cylinder 3 so as to face the passage member 13. The connection plate 20 and the passage member 13 include an annular oil passage 1
Connection pipes 21 and 22 communicating with 5 and 18, respectively, are inserted and fitted. Further, the connection plate 20 has a reservoir chamber 4
Is provided with a connection hole 23 communicating with the connection hole. The connection plate 20 is connected to a damping force generating mechanism 24.

The damping force generating mechanism 24 has a bottomed cylindrical case 25.
Two proportional cylindrical actuators 28A (hereinafter referred to as actuators 28A) are screwed into the openings, and the inside of the case 25 is formed by the valve members 26 and 27. Three oil chambers 25a, 25b, 25
It is divided into c. Each of the valve members 26 and 27 has an annular seal member 28 or 29 fitted in an opening thereof, and a substantially cylindrical guide member 30 is inserted into the valve member 26 so that the distal end of the valve member 26 or 27 is actuated.
It is screwed to 28A and fixed together with them. Case
Connection holes 31, 32, 33 communicating with the oil chambers 25a, 25b, 25c are provided on the side wall of the connection hole 31, 25, 25c.
33 is a connecting pipe 21 provided on the connecting plate 20,
The connection pipe 22 is connected to the connection hole 23.

At the bottoms of the valve members 26 and 27, a plurality of (only two are shown) oil passages 34 and 35 (main passages) arranged along the circumferential direction respectively penetrate in the axial direction. Also,
On the inner walls at the bottoms of the valve members 26 and 27, oil passages 34 and
Annular inner seal portions 36 and 37 project from the inner peripheral side of 35, and annular valve seats 38 and 39 project from the outer peripheral side of the oil passages 34 and 35. Further, the valve members 26 and In the vicinity of the side wall 27, annular outer seal portions 40 and 41 are protruded. In addition, valve seat 38,
Annular grooves 42, 43 are provided between the outer seals 40, 41 and 39.
(Main passages) are formed, and the grooves 42, 43 communicate with the oil chambers 25b, 25c via oil passages 44, 45, respectively.

The inner peripheral portions of the valve members 26 and 27 are fixed to the inner seal portions 36 and 37, and the outer peripheral portions thereof are valve seats 38 and 39, respectively.
Disc valves 46 and 47 (a valve element of a main damping valve) that come into contact with are provided. In the valve members 26 and 27, annular seal rings 48 and 49 (outer seal portions) are fitted and abut against the outer seal portions 40 and 41.
Retainer rings 50 and 51 having an inner diameter larger than the seal rings 48 and 49 are laminated thereon (two in the illustrated case), and further, a disc-shaped leaf spring having an inner peripheral portion fixed to the guide member 30.
52, 53 are fixed to the valve members 26, 27 with their outer peripheral portions abutting against the retainer rings 50, 51. The inner peripheral portions of annular seal disks 54 and 55 abut against the back surfaces of the disk valves 46 and 47, respectively.
The outer peripheral portion of 55 is inserted inside the retainer rings 50, 51 and is in contact with the inner peripheral portions of the seal rings 48, 49. That is, the seal disks 54 and 55 are
They are in contact with the outer seal portions 40, 41 via 8, 49.
The seal disks 54 and 55 are in contact with the outer peripheral portions of disk-shaped valve springs 56 and 57 (spring means) whose inner peripheral portions are fixed to the guide member 30 so that the disk valves 46 and 47 and the seal rings 48 and
Pressed to the 49 side. The side walls of the valve members 26 and 27, the disk valves 46 and 47, the seal disks 54 and 55, and the seal members 28 and 29 respectively cause the pilot chamber 5
8,59 have been defined.

The pilot chamber 5 is provided on the side wall of the guide member 30.
Ports 60, 61 and oil chamber 25b communicating with 8, 59, respectively
, 25c are provided with ports 62 and 63, respectively. Notches 64, 65 (fixed orifices) are provided in the inner seal portions 36, 37 of the valve members 26, 27, respectively, and the notches 64, 65 are provided in grooves 66, 65 provided in the outer peripheral portion of the guide member 30, respectively. Ports 60 and 61 via 67 (upstream passage)
That is, they are communicated with the pilot rooms 58, 59. Also,
In the guide member 30, between the ports 60 and 62 and the ports 61 and
Spools 68 for adjusting respective flow passage areas between 63 are slidably fitted. The spool 68 is urged toward the actuator 28A by a compression spring 69. The spool 68 is moved by the operating rod 70 of the actuator 28A against the urging force of the spring 69, so that the ports 60 and 63 (downstream passage,
The orifice area of the variable orifice can be adjusted.

The operation of the present embodiment having the above-described configuration will now be described. 1 and 2, the solid arrows indicate the flow of the oil liquid during the extension stroke of the piston rod 6, and the broken arrows indicate the flow of the oil liquid during the contraction stroke.

During the extension stroke of the piston rod 6, the piston check valve 10 closes due to the movement of the piston 5, and the oil liquid in the cylinder upper chamber 2a side is pressurized. 16, flows through the annular oil passage 15, the connection pipe 21 to the connection hole 31 of the damping force generating mechanism 24, and further flows from the connection hole 31 to the oil chamber 25a, the oil passage 34, the notch 64, the groove 66, the port 60, the port 62. ,
Oil chamber 25b, connection hole 32, connection pipe 22, annular oil passage 18, and oil passage
It flows through 19 to the cylinder lower chamber 2b. At this time, when the pressure on the cylinder upper chamber 2a side reaches the valve opening pressure of the disc valve 46, the disc valve 46 is opened and the oil liquid flows from the oil chamber 25a through the oil passage 34, the groove 42 and the oil passage 44 to the oil chamber. Flows directly to 25b. On the other hand, the amount of oil that the piston rod 6 has withdrawn from the cylinder 2 is discharged from the reservoir chamber 4 to the check valve of the base valve 8.
12 is opened to flow to the cylinder lower chamber 2b.

Therefore, during the extension stroke, the piston speed is low and before the disc valve 46 is opened, a damping force having an orifice characteristic is generated according to the flow path area of the notch 64, the groove 66 and the port 60, and the piston speed is reduced. When the pressure rises, the pressure on the cylinder upper chamber 2a side increases, and the disc valve 46 opens, a damping force having valve characteristics is generated according to the degree of opening, thereby suppressing an excessive increase in the damping force.

The damping force is adjusted by moving the spool 68 by energizing the actuator 28A to change the flow passage area of the port 60. In this case, the smaller the flow passage area of the port 60, the greater the pressure loss due thereto and the higher the pressure in the pilot chamber 58 on the upstream side, so that the valve opening pressure of the disk valve 46 increases, and The larger the flow path area, the smaller the pressure loss and the lower the pressure in the pilot chamber 58 on the upstream side, so that the valve opening pressure of the disc valve 46 decreases. In this manner, by changing the flow path area of the port 60, the valve opening pressure of the disk valve 46 changes at the same time, and the orifice characteristics and valve characteristics change. Characteristics can be adjusted.

At the time of the contraction stroke, the check valve 10 of the piston 5 is opened with the movement of the piston 5, and the oil liquid in the cylinder lower chamber 2b flows directly into the cylinder upper chamber 2a through the oil passage 9. Since the cylinder upper and lower chambers 2a and 2b have substantially the same pressure, no oil liquid flows between the connection holes 31 and 32 of the damping force generating mechanism 24. On the other hand, as the piston rod 6 enters the cylinder 2, the check valve 12 of the base valve 8 closes, and the oil liquid in the cylinder 2 is pressurized by the amount of the piston rod 6 entering, and the broken line in FIG. As indicated by arrows, the oil flows from the cylinder lower chamber 2b through the oil passage 19, the annular oil passage 18 and the connection pipe 22 to the connection hole 32 of the damping force generating mechanism 24, and further from the connection hole 32 to the oil chamber 25b, the oil passage 35, notch 65, groove 67, port 61,
It flows to the reservoir chamber 4 through the port 63, the oil chamber 25c, the connection hole 33 and the connection hole 23. At this time, when the pressure on the cylinder 2 side reaches the valve opening pressure of the disc valve 47, the disc valve 47 is opened and the oil liquid flows from the oil chamber 25b to the oil chamber 25c through the oil passage 35, the groove 43 and the oil passage 45. Flows directly.

Therefore, during the contraction stroke, the piston speed is low and before the disc valve 47 is opened, a damping force having an orifice characteristic is generated according to the flow path area of the notch 65, the groove 67 and the port 63, and the piston speed is reduced. When the pressure rises, the pressure on the cylinder 2 side increases, and the disk valve 47 opens, a damping force having valve characteristics is generated in accordance with the opening degree, thereby suppressing an excessive increase in the damping force.

Then, as in the above-described extension stroke, the spool
The orifice characteristics are adjusted by moving 68 and changing the flow area of the port 63, and the pressure loss in the pilot chamber 59 is changed to change the valve opening pressure of the disc valve 47 to adjust the valve characteristics. Therefore, the damping force characteristic can be adjusted from a low piston speed range to a high piston speed range.

The movement of the spool 68 causes the port 60 to move.
By changing the flow passage area of the port 63 and the port 63, the damping force characteristics can be adjusted on the extension side and the contraction side, respectively. In this case, for example, according to the position of the spool 68, the flow path areas of the ports 60, 63 on the extension side and the contraction side are such that when one is large, the other is small, and when one is small, the other is large. By arranging the lands of the ports 60, 63 and the spool 68, a combination of damping force characteristics of different sizes on the extension side and the contraction side (for example, the extension side is hard and the contraction side is soft, or the extension side is soft and the contraction side is hard Can be selected at the same time.

Further, since the pilot chambers 58 and 59 are formed without providing a sliding portion, leakage of oil from the pilot chambers 58 and 59 can be reduced and stable damping force characteristics can be obtained. Further, variation in damping force due to temperature change can be reduced. Further, since it is not necessary to process a sliding portion requiring high working accuracy, manufacturing cost can be reduced. In addition, inner seals 36 and 37, valve seat 3
8, 39 and outer seal portions 40, 41 are provided with valve members 26, 27.
Can be formed integrally with the disk valves 46, 47, so that the error of the protrusion height can be reduced.
Of the valve opening pressure can be reduced.

In the above embodiment, the valve member 26,
The seal rings 48 and 49 are brought into contact with the outer seal portions 40 and 41 of the 27, and the seal disks 54 and 55 are brought into contact with the seal rings 48 and 49, but the seal rings 48 and 49 are omitted. The sealing discs 54, 55 may be brought into direct contact with the outer sealing portions 40, 41.

Next, a second embodiment of the present invention will be described with reference to FIGS. It should be noted that the second embodiment is generally the same as the first embodiment except that the seal structure on the bottom side of the valve member of the pilot chamber of the damping force generating mechanism and the structure of the valve spring are different. Therefore, only the damping force generating mechanism is shown in FIG.
The same parts as those shown in FIG. 2 are denoted by the same reference numerals, and only different parts will be described in detail.

As shown in FIGS. 3 and 4, the damping force generating mechanism 71 according to the second embodiment differs from the damping force generating mechanism 24 of the first embodiment shown in FIGS. Rings 48, 49, retainer rings 50, 51 and leaf spring 5
The seal disks 54 and 55 are brought into direct contact with the outer seal portions 40 and 41 by omitting the seals 2 and 53. Notches 56a, 57 are formed in the outer peripheral portions of the disc-shaped valve springs 56, 57 (leaf springs).
a and (oil passage) is formed, the notch 56a, by 57a, a space S _1, S _2, which is formed between the disc valve 46, 47 and the seal disc 54, 55 and the valve spring 56, 57, The pilot chambers 58 and 59 are in communication with each other.

With this configuration, the spaces S ₁ , S ₂ and the pilot chambers 58, 59 are communicated through the notches 56 a, 57 a and always have the same pressure, so that the pressure in the pilot chambers 58, 59 increases. Since the spaces S ₁ and S ₂ are not crushed,
It is possible to suppress an increase in the frictional force of the contact portion between the space S _1, S valve spring 56 associated with the compression of ₂ and the seal discs 54, 55 and disk valve 46, the disk valve 46, 47 The operation is smooth, and a stable damping force can be obtained.
Also, when assembling the damping force adjustable hydraulic shock absorber, the notch 56
Since the air in the spaces S ₁ and S ₂ can be discharged by the a and 57a, the air can be easily removed. The valve springs 56 and 57 have spaces S ₁ and S ₂ and pilot chambers 58 and 57, respectively.
A through hole may be provided instead of the cutouts 56a and 57a as an oil passage communicating with 59.

Next, a third embodiment of the present invention will be described with reference to FIGS. Note that the third embodiment is generally the same as the second embodiment except that the structure of an oil passage constituting an upstream passage communicating with the pilot chambers 58 and 59 of the damping force generating mechanism is different. Since it is configured, only the damping force generating mechanism is shown, and the same parts as those shown in FIGS. 3 and 4 are denoted by the same reference numerals, and only the different parts will be described in detail.

As shown in FIGS. 5 and 6, the damping force generating mechanism 72 according to the third embodiment differs from the damping force generating mechanism 71 of the second embodiment shown in FIGS. Notches 64, 65 provided in the inner seal portions 36, 37 of the member and grooves 66, 67 provided in the guide member 30 are omitted, and instead, the oil passages 34, 35 are provided in the disc valves 46, 47. Orifice passages 73 and 74 (fixed orifices) communicating the spaces S ₁ and S ₂ are provided. The notches 56a, 57a of the valve spring 56, the space S _1, S ₂ and the orifice passage 73,
74, the pilot chambers 58, 59 and the disc valves 46,
An upstream side passage communicating with the upstream side of 47 is formed.

With this configuration, the oil liquid can be circulated from the oil passages 34 and 35 to the pilot chambers 58 and 59 through the orifice passages 73 and 74, and the same operation and effect as those of the first and second embodiments can be obtained. Can be played. Further, the spaces S ₁ and S ₂ and the pilot chamber 5 are formed by the orifice passages 73 and 74.
Since the 8,59 direct hydraulic fluid to flow, it is possible to facilitate the flow of hydraulic fluid in the space S _1, S ₂ and the pilot chamber 58, 59, during assembly of the damping force adjustable hydraulic shock absorber The air bleeding operation can be easily performed. Furthermore, compared to the case where the notch and the groove are formed in the valve member and the guide member to provide the upstream passage and the fixed orifice, the upstream passage and the fixed orifice can be easily formed only by punching out the disk valve, Orifice passage 73, 74
By changing the diameter, the setting of the damping force characteristic can be easily changed.

In this embodiment, the disc valve 4
The orifice passages 73, 74 of 6, 47 are fixed orifices of the upstream passage, but the cutouts 56a, 57a of the valve springs 56, 57 may be fixed orifices, or both of them may be used as fixed orifices. .

Next, a fourth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. The fourth embodiment is generally similar to the configuration of the third embodiment except that a sub damping valve is provided upstream of the fixed orifice of the damping force generating mechanism. Only the damping force generating mechanism is shown, and the same parts as those shown in FIGS. 5 and 6 are denoted by the same reference numerals, and only different parts will be described in detail.

As shown in FIGS. 7 and 8, in the damping force generating mechanism 75 according to the fourth embodiment, the inner walls of the bottoms of the valve members 26 and 27 are provided on the inner peripheral sides of the valve seats 38 and 39, respectively. ,valve seat
Annular valve seats 76 and 77 having a projecting height smaller than 38 and 39 are protruded, and the inner peripheral portion is fixed to the inner seal portions 36 and 37 together with the disc valves 46 and 47, and the outer peripheral portion is Valve seat 7
Sub disc valves 78, 79 seated on 6, 77 (sub damping valve)
Is provided. The auxiliary disc valves 78 and 79 are
The valve opens and flexes in response to the pressure of the oil chambers 25a and 25b on the sides 4 and 35, and generates a damping force having valve characteristics according to the opening degree. 78a,
The 79a forms an orifice passage that always allows the oil passages 34 and 35 to flow. The auxiliary disk valve 78,
The valve opening pressure of 79 is set sufficiently lower than the valve opening pressure of the disc valves 46 and 47.

With this configuration, in addition to the operation and effect of the third embodiment, during the extension and retraction stroke of the piston rod 6,
Before opening the disc valves 46 and 47 (low-speed range of piston speed), in the extremely low-speed range of piston speed, the damping force of the orifice characteristic is formed by the orifice passages formed by the notches 78a and 79a of the sub-disk valves 78 and 79. When this occurs and the piston speed increases, the sub-disk valves 78 and 79 open, and a damping force of valve characteristics is generated according to the degree of opening.

Therefore, as shown by the solid line in FIG. 9, the damping force characteristic is not changed until the valve opening point A of the sub-disk valves 78, 79 is reached.
The orifice passage formed by the notches 78a and 79a has orifice characteristics.
The valve characteristics correspond to the opening degrees of 78 and 79, and after the opening point B of the disc valves 46 and 47, the disc valve 4
Valve characteristics according to 6, 47 opening. In this way, by setting the bending point (valve opening point A) in the damping force characteristic in the low speed region of the piston speed by the sub-disk valves 78 and 79, the damping force characteristic in the low speed region is optimized,
It is possible to sufficiently secure the damping force in an extremely low speed range. The dashed line in FIG. 9 indicates the first disk having no auxiliary disk valve.
13 shows the damping force characteristics of the third to third embodiments.

The dimensions of the main parts of the damping force generating mechanisms 24, 71, 72, 75 of the above-described embodiments will be described with reference to FIG. If the diameter D ₁ was 28.7 mm, the inner diameter of the seal disc 54, 55
D ₂ is set to about 24.0 to 26.0 mm, and valve springs (spring means) 56, 57
Outer diameter D ₃ of about 26.0 to 30.0 mm, and outer seal portions 40 and 41
An inner diameter D ₄ is about 31.0～33.0Mm, also desirably in achieving optimization be about 0.2 to 0.5 mm the step H between the valve seat 38, 39 and the outer seal portion 40, 41, these It has been experimentally obtained that the numerical values (D ₂ , D ₃ , D ₄ ) are in a proportional relationship.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. The damping force-adjustable hydraulic shock absorber of the fifth embodiment has substantially the same structure as that of the first embodiment shown in FIG. 1 with respect to the cylinder portion and the reservoir. The same parts as those of the first embodiment are denoted by the same reference numerals, and only different parts will be described in detail.

As shown in FIGS. 10 to 12, in the damping force adjustable hydraulic shock absorber 80 of the fifth embodiment, the cylinder 2
The tube 81 is externally fitted to form an annular passage 82 between the cylinder 2 and the tube 81. The annular passage 82 is communicated with the cylinder upper chamber 2a by an oil passage 16 provided on a side wall near the upper end of the cylinder 2. An opening 83 is provided on a side wall of the tube 81. In the damping force adjusting type hydraulic shock absorber 80, the oil passage 19 of the cylinder 2 shown in FIG. 1 is not provided.

A damping force generating mechanism 84 is mounted on the side surface of the outer cylinder 3. In the damping force generating mechanism 84, one end opening having a flange portion 85 a of a cylindrical case 85 is welded to the side wall of the outer cylinder 3. The case 85 has a flange 85a
A passage member 86, a valve member main body 87, a cylindrical member 88, and a guide member 89 (seal member) are inserted so as to contact each other in order from the side. A proportional solenoid 90 is fitted into the opening at the other end of the case 85, and is fixed by being screwed into a retainer 91.When the proportional solenoid 90 is brought into contact with the guide member 89, the passage member 86, the valve The member main body 87, the cylindrical member 88, and the guide member 89 are fixed.

The passage member 86 has a small-diameter opening 86a at one end thereof fitted in the opening 83 of the tube 81, and an oil chamber 92 formed in the passage member 86 communicates with the annular passage 82. An annular oil passage 93 is formed between the passage member 86 and the cylindrical member 88 and the case 85, and the annular oil passage 93 is connected to the reservoir chamber via an oil passage 94 provided in a flange portion 85a of the case 85. 4
Is communicated to.

The valve member main body 87 is a substantially disk-shaped member.
The cylindrical member 88 is connected to form a bottomed cylindrical valve member. A plurality of (only two are shown) oil passages 95 arranged along the circumferential direction are passed through the bottom of the valve member, that is, the valve member main body 87 in the axial direction. At one end of the valve member body 87, an annular inner seal portion 96 is protruded on the inner peripheral side of the plurality of oil passages 95, and an annular valve seat 97 is protruded on the outer peripheral side of the plurality of oil passages 95, An annular groove 98 (groove portion) is formed on the outer peripheral side of the valve seat 97, and an annular outer seal portion 122 is protrudingly provided on the outer peripheral side of the annular groove 98. The outer peripheral portion of the outer seal portion 99 is in contact with the side wall of the valve member, that is, the inner peripheral surface of the cylindrical member 88. Further, the annular groove 98 is communicated with the annular oil passage 93 by an oil passage 100.

The valve member body 87 is provided with a disk valve 101 whose inner peripheral portion is fixed to the inner seal portion 96 and whose outer peripheral portion is seated on the valve seat 97. The inner peripheral portion of the annular seal disk 102 is in contact with the back surface of the disk valve 101, and the outer peripheral portion of the seal disk 102 is in contact with the outer seal portion 99. The outer periphery of a disc-shaped valve spring 103 (spring means) whose inner periphery is fixed to the valve member main body 87 is brought into contact with the seal disk 102, and is pressed toward the disc valve 101 and the outer seal portion 99. I have. Disc valve 10
1 and the valve spring 103 are attached to the valve member main body 87 by screwing a nut 105 to a pin 104 inserted into the central opening of the valve member main body 87.

An annular projection 107 is formed on the rear surface of the disk valve 101 along the circumferential direction thereof, and the inner peripheral portion of the seal disk 102 is in contact with the tip of the projection 107.

A pilot chamber 106 is defined by the disk valve 101, the seal disk 102, the cylindrical member 88 and the guide member 89.
An oil passage 104a (upstream passage) provided in the pin 104 communicates with the oil chamber 92 via a fixed orifice 104b.

The valve member body 87, the disc valve 101,
A main damping valve A (pilot type main damping valve) is constituted by the seal disk 102 and the pilot chamber 106,
The main damping valve A is opened when the disc valve 101 receives the pressure of the oil liquid from the oil passage 95 to generate a damping force corresponding to the opening degree, and acts on the internal pressure of the pilot chamber 106 in the valve closing direction. The valve opening pressure is adjusted as the pilot pressure to be adjusted.

The guide member 89 is provided with a bore 109 communicating with the pilot chamber 106 so as to face the solenoid 108 of the proportional solenoid 90. On the inner surface of bore 109,
An annular groove 110 is formed, and the annular groove 110 is
(Downstream passage) communicates with the annular oil passage 93.
A spool 112 is slidably fitted in the bore 109. The flow control valve B is connected between the bore 109 and the spool 112.
(Variable orifice), and a proportional solenoid 90
The spool 112 moves against the urging force of the springs 113 and 114 to open and close the annular groove 110 in response to the current supplied to the solenoid 108, thereby increasing the flow passage area between the bore 109 and the oil passage 111. Adjustments are made. The proportional solenoid 90 is provided with an adjusting screw 115 for adjusting the initial load of the spring 113 on the spool 112.

In the above configuration, the oil passage 16 and the annular passage 8
2, small-diameter opening 86a, oil chamber 92, oil passage 95, annular groove 98, oil passage 1
00, the cylinder upper chamber 2 by the annular oil passage 93 and the oil passage 94.
It forms a main passage for communicating a with the reservoir chamber 4.

The operation of the present embodiment configured as described above will now be described.

During the extension stroke of the piston rod 6, the check valve of the piston 5 closes as the piston 5 moves,
The oil liquid in the cylinder upper chamber 2a is pressurized and flows through the oil passage 16, the annular passage 82 and the small-diameter opening 86a to the oil chamber 92 of the damping force generating mechanism 84, and further, the oil passage 104a and the fixed orifice 104.
b, pilot chamber 106, bore 109, annular groove 110, oil passage 111
Flows through the annular oil passage 93 and the oil passage 94 to the reservoir chamber 4. At this time, the pressure on the cylinder upper chamber 2a side becomes the main damping valve A
When the valve opening pressure is reached, the main damping valve A opens and the oil liquid
From 92, the oil flows through the oil passage 95, the annular groove 98 and the oil passage 100 to the annular oil passage 93. On the other hand, the amount of oil that has been moved by the piston 3 flows from the reservoir chamber 4 to the cylinder lower chamber 2b by opening the check valve 12 of the base valve 8.

Before the main damping valve A is opened, damping force is generated due to the flow passage area of the fixed orifice 104b and the flow control valve B before the main damping valve A is opened. When the piston speed increases and the pressure in the cylinder upper chamber 2a increases to open the main damping valve A, a damping force corresponding to the opening degree is generated. At this time, the smaller the flow passage area of the flow control valve B, the greater the pressure loss and the higher the pressure in the pilot chamber 106 on the upstream side, so the pilot pressure of the main damping valve A increases, and this pilot pressure becomes , Acting in the direction to close the disc valve 101, the valve opening pressure of the main damping valve A increases. Therefore, by changing the flow area of the flow control valve B by the current flowing through the solenoid 108, the orifice characteristics can be directly adjusted and the pilot chamber 106 can be controlled.
, The valve characteristics can be adjusted by changing the opening pressure of the main damping valve A, so that the damping force characteristics can be adjusted from a low piston speed range to a high piston speed range.

During the compression stroke of the piston rod 6, the check valve 12 of the base valve 8 closes and the oil in the cylinder lower chamber 2b opens the check valve 10 of the piston 5 with the movement of the piston 5. The oil fluid that flows into the upper chamber 2a and intrudes into the cylinder 2 by the piston rod 6 flows from the cylinder upper chamber 2a through the same flow path as in the above-described extension stroke.
It flows to the reservoir 4 side.

Therefore, as in the case of the above-described extension stroke, the piston speed is low and before the main damping valve A is opened, the fixed orifice 10
When the damping force of the orifice characteristic is generated by the flow path area of the flow control valve 4b and the flow control valve B, the piston speed increases, the pressure on the cylinder upper chamber 2a side increases, and the main damping valve A is opened. Accordingly, a damping force having valve characteristics is generated to suppress an excessive increase in the damping force.

The flow area of the flow control valve B is changed by the current flowing through the solenoid 108,
Adjust the orifice characteristics directly, and
The valve characteristics can be adjusted by changing the pressure of 106, and the damping force characteristics can be adjusted from a low speed range to a high speed range of the piston speed. In the contraction stroke, the pressure receiving area of the piston rod 6 is smaller than that in the extension stroke, and accordingly, the damping force is smaller than that in the extension stroke.

As in the first to fourth embodiments, since the pilot chamber 106 is formed without providing a sliding portion, the leakage of the oil liquid from the pilot chamber 106 is reduced, and a stable damping force characteristic is obtained. Can be obtained, and variation in the damping force due to a temperature change can be reduced. Further, since it is not necessary to process a sliding portion requiring high working accuracy, manufacturing cost can be reduced. further,
Since the inner seal portion 96, the valve seat 97, and the outer seal portion 99 can be formed integrally with the valve member body 87, errors in their protruding heights can be reduced, and the valve opening pressure of the disc valve 101 can be reduced. Can be reduced.

Here, as shown in FIG. 13, when the disk valve 101 is not provided with the projection 107, the diameter of the contact portion between the seal disk 102 and the disk valve 101 becomes the normal diameter d _1. When the pressure in the pilot chamber 106 causes the disc valve 101 and the seal disc 102 to bend toward the valve member body 87 due to the increase in the pressure in the pilot chamber 106, the diameter d ₂ (see the upper part of FIG. 13). ), and becomes larger than the diameter d ₁ of the normal state. As a result, the outer peripheral side of the disc valve 102 is pressed in the valve closing direction, and as a result, the pressure receiving area of the disc valve 102 against the internal pressure of the pilot chamber 106 increases.
102 becomes difficult to open. Thus, the pilot room 10
Due to the bending of the disk valve 101 and the seal disk 102 due to the internal pressure of 6, the valve opening pressure of the disk valve 101 varies, making it difficult to obtain a stable damping force.

On the other hand, in the present embodiment, in the main damping valve A, the inner peripheral portion of the seal disk 102 comes into contact with the distal end of the annular projection 107 provided on the back surface of the disk valve 101. Therefore, even if the pressure in the pilot chamber 106 rises and the disk valve 101 and the seal disk 102 bend toward the valve member body 87 due to the pressure, the contact between the seal disk 102 and the disk valve 101 can occur. Part, ie, the diameter d ₁ of the tip of the protrusion 101 (see FIG.
12) does not change and remains constant.
Thus, a stable damping force can be obtained by preventing a variation in the valve opening pressure of the disc valve 101 with respect to the internal pressure.

The protrusion 107 of the fifth embodiment is
Each of the disk valves 46, 47 of the first to fourth embodiments
May be provided.

Further, in the fifth embodiment, an example in which the disk valve 101 is constituted by one disk has been described. However, the present invention is not limited to this, and the disk valve 101 may be constituted by a plurality of disks, and the seal disk 102 may be constituted. The protrusion 107 may be provided only on the disk facing the disk. Thus, when the disk valve 101 is composed of a plurality of disks, the thickness of each disk can be reduced, and the processing of the projection 107 can be facilitated. Further, the disk facing the valve seat 79 may be formed as a disk having a notch in the outer peripheral portion to form an orifice.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. The sixth embodiment is different from the second embodiment in that a retainer disk is interposed between a disk valve and a seal disk constituting a main damping valve of a damping force generating mechanism. Are generally similar in construction, so only the main damping valve and pilot chamber parts are shown, and parts similar to those shown in FIGS. 3 and 4 are given the same numbers and detailed only in different parts. Will be described.

As shown in FIG. 14, in the damping force-adjustable hydraulic shock absorber according to the sixth embodiment, a disk-shaped retainer having a slightly smaller diameter than the disk valves 46, 47 is provided on the disk valves 46, 47. Disks 120 and 121 are stacked. The inner circumference of the retainer disks 120 and 121 has a disk valve 4
Clamped together with 6, 47, disc valve 46, 4
It bends with 7. The inner peripheral ends of the seal disks 54, 55 are in contact with the outer peripheral ends of the retainer disks 120, 121. That is, the sealing disk
54 and 55 are in contact with disk valves 46 and 47 via retainer disks 120 and 121.

Here, the overlap margin W of the contact portions between the retainer disks 120, 121 and the seal disks 54, 55 is set sufficiently small. Also, retainer discs 120, 12
(1) The contact part between the seal discs 54 and 55 and the outer seal part
The step h with respect to 40 and 41 is set to be larger than the maximum lift amount of the disc valves 46 and 47, and the lower ends of the inner peripheral edges of the seal discs 54 and 55 are always kept at the retainer discs 120 and 121.
To come into contact with the upper surface.

In the sixth embodiment, the pilot chamber 5
Fixed orifices 123, 124 in the upstream passage communicating with 8, 59
However, it is provided separately from the notches 64 and 65.

With this configuration, in addition to the operation and effect of the second embodiment, the retainer disks 120 and 121 are interposed between the disk valves 46 and 47 and the seal disks 54 and 55, and the seal disks 54 and 55 and retainer disk 12
Since the overlap margin W between 0 and 121 is sufficiently small,
The pressure in the pilot chambers 58 and 59 increases, and the pressure causes the disc valves 46 and 47 and the retainer discs 120 and 12 to move.
1 and the seal disks 54 and 55 are bent toward the bottom of the valve members 26 and 27, and the seal disks 54 and 55 and the retainer disks are opened by opening (lifting) the disk valves 46 and 47.
Even when the contact angle between 120 and 121 is reduced, it is possible to suppress sufficiently reduce the change in diameter D ₂ of the contact portion between the seal disc 54, 55 and the retainer disc 120 and 121.
As a result, similar to the fifth embodiment, the pilot chamber 5
Variations in the valve opening pressures of the disc valves 46 and 47 with respect to the pressures of 8, 59 can be reduced, and a stable damping force can be obtained.

In this case, the retainer disks 120, 121
Is a disk-shaped member, so that it can be easily processed with desired accuracy and sufficient strength can be obtained.
The manufacturing cost is low, the deterioration with time is small, and the durability is high.

Next, a seventh embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. The seventh embodiment is different from the second embodiment in that a seat member is interposed between a disk valve and a seal disk constituting a main damping valve of a damping force generating mechanism, and an outer seal portion and a seal ring are provided. 3 and 4 except that a seal ring is interposed between the main damping valve and the pilot chamber. Portions are assigned the same numbers and only different portions will be described in detail.

As shown in FIG. 15, in the damping force adjusting type hydraulic shock absorber according to the seventh embodiment, between the disk valves 46, 47 and the sealing disks 54, 55, the annular seat members 125,
An annular seal ring 127, 128 is provided between the outer seal portions 40, 41 and the seal discs 54, 55.
Is interposed.

The outer peripheral edges of the seat members 125 and 126 are projected downward to form annular positioning convex portions 129 and 130, and the inner peripheral portions of the positioning convex portions 129 and 130 are connected to the disc valve.
By being brought into contact with the outer peripheral surfaces of 46 and 47, they are positioned on the disc valves 46 and 47. Seat member 125,
On the inner peripheral side of the lower surface of 126, annular projections 131 and 132 (first projections) that contact the disk valves 46 and 47 are formed. On the upper surfaces of the sheet members 125 and 126, annular projections 13 abutting on the seal disks 54 and 55 are provided at positions intermediate the positioning projections 129 and 130 and the projections 131 and 132.
3,134 (second protrusions) are formed. That is,
The seal disks 54, 55 are in contact with the disk valves 46, 47 via seat members 125, 126.

The seal rings 127 and 128 are
With the provision of 25 and 126, the outer peripheral portions of the seal disks 54 and 55 whose inner peripheral portions have been lifted are lifted to optimize the mounting angle of the seal disks 54 and 55. Therefore, the height of the outer seal portions 40 and 41 is set according to the seat members 125 and 126, that is,
By forming the seal ring integrally with the outer seal portion, the seal rings 127 and 128 can be omitted.

With this structure, in addition to the operation and effect of the second embodiment, the seal disks 54 and 55
Disc valve through 125, 126 projections 131, 132
Since they are in contact with 46, 47, the pressure in pilot chambers 58, 59 rises, and due to the pressure, the disc valves 46, 47
Even when the seal disks 54 and 55 are bent toward the bottom of the valve members 26 and 27, the contact portions between the seal disks 54 and 55 and the seat members 125 and 126, that is, the protrusions 131 and 132
The diameter D ₅ of the tip portion of a constant unchanged. as a result,
As in the fifth embodiment, the variation in the valve opening pressure of the disc valves 46, 47 with respect to the pressure of the pilot chambers 58, 59 can be reduced, and a stable damping force can be obtained.

The projections 13 of the sheet members 125, 126
The pressure of the pilot chambers 58 and 59 is applied to a portion on the inner peripheral side of the inner peripheral ends (diameter D ₆ ) of the seal disks 54 and 55 of the disk valves 46 and 47 by the diameters 1 and 132 (diameter D ₅ ). When the disc valves 46 and 47 are opened (lifted), the seat members 125 and 126 move in parallel along the axial direction of the disc valves 46 and 47. Therefore, when the disc valves 46 and 47 are opened (lifted), The outer peripheral portions of the valves 46 and 47 abut against the central portions of the seal disks 54 and 55,
4 and 55 to the outer seals 40 and 41 (seal rings 127 and 128)
Pilot room 5)
The valve opening pressures of the disc valves 46 and 47 with respect to the pressures of 8 and 59 can be set small, and the degree of freedom in setting the damping force characteristics can be increased.

When the inner peripheral ends of the seal disks 54 and 55 are brought into direct contact with the inner peripheral portions of the disk valves 46 and 47, when the disk valves 46 and 47 are opened (lifted), The outer peripheral portions of the disc valves 46 and 47 abut the center portions of the seal discs 54 and 55,
55 is lifted from the outer seal portions 40 and 41 (seal rings 127 and 128), and the pilot chambers 58 and 59 and the downstream side of the main passage are in communication with each other. Will decrease.

Next, an eighth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. The eighth embodiment is different from the fifth embodiment in that a retainer ring is interposed between an outer seal portion and a seal ring constituting a main damping valve of a damping force generating mechanism. Since they are generally configured in the same manner, only the main damping valve and the pilot chamber are shown, and the same parts as those shown in FIGS. 10 to 12 are denoted by the same reference numerals and only different parts are described in detail. explain.

As shown in FIG. 16, in the damping force-adjustable hydraulic shock absorber according to the eighth embodiment, an annular retainer ring 135 is interposed between the outer seal portion 99 and the seal disk 102. The outer circumference of the retainer ring 135 is a cylindrical member 88.
Fitted in, and the inside diameter d _b (diameter of the inner tangent with the valve seat 97 and the disk valve 101) the inner diameter d _a of the valve seat 97 (inner tangential diameter of the seal disc 102) and the disc valve 101 ratio is in such a d _b / d _a ≦ 1.2.

With this configuration, the pressure receiving area of the seal disk 102 can be reduced to a substantially appropriate level by the retainer ring 135, the pilot pressure acting on the disk valve 101 is optimized, and the damping force characteristic at the time of hardware is improved. Can be optimized.

[0091] In the above eighth embodiment, but so as to set the inner diameter d ₃ of the outer sealing portion by a retainer ring 135 separate, so as to form a retainer ring 135 integral with the outer seal portion 99 You may. Also in addition to the first to seventh embodiment, the eighth embodiment as well as the ratio of the inner diameter D ₄ of the inner diameter D ₁ and the outer seal portion of the valve seat disk valve of the main damping valve D ₄ By setting / D ₁ ≦ 1.2 (see FIG. 4), it is possible to optimize the damping force characteristics at the time of hardware.

[0092]

As described above in detail, according to the damping force adjusting type hydraulic shock absorber of the first aspect, the flow path area between the cylinder upper and lower chambers is changed by changing the flow path area of the downstream passage by the variable orifice. The damping force characteristic (orifice characteristic) is adjusted by directly changing the area, and the internal pressure of the pilot chamber is changed according to the pressure loss due to the variable orifice to change the damping valve opening characteristic. Characteristic), the adjustment range of the damping force characteristic can be widened. Further, since the pilot chamber is formed without providing the sliding portion, it is possible to obtain a stable damping force characteristic by reducing leakage of the oil liquid from the pilot chamber, and to reduce variation in the damping force due to a temperature change. can do. Further, since it is not necessary to process a sliding portion requiring high working accuracy, manufacturing cost can be reduced. Further, since the inner seal portion, the valve seat, and the outer seal portion of the valve member can be integrally formed, errors in the protruding heights thereof are reduced, and variations in the valve opening pressure of the disc valve are reduced. Can be.

According to the damping force adjusting type hydraulic shock absorber of the second aspect, the space formed by the disc valve, the seal disc and the leaf spring and the pilot chamber are communicated via the oil passage so that the same pressure is always maintained. Therefore, when the pressure in the pilot chamber increases, the space is not crushed. As a result, it is possible to suppress an increase in the frictional force at the contact portion between the leaf spring, the seal disk and the disk valve due to the compression of the space, and to obtain a stable damping force by smoothing the operation of the disk valve. it can. Further, at the time of assembling the damping force adjusting type hydraulic shock absorber, the air in the space can be discharged by the oil passage, so that the air bleeding operation can be easily performed.

According to the damping force adjusting type hydraulic shock absorber of the third aspect, before the main damping valve is opened, the damping force of the valve characteristic can be generated by the sub damping valve, and the damping force characteristic in the low speed range can be improved. In addition to the optimization, it is possible to sufficiently secure the damping force in an extremely low speed range.

According to the damping force adjusting type hydraulic shock absorber of the fourth aspect, since the projection is provided on the back surface of the disc valve, the disc valve and the seal disc are bent by the rise of the pressure in the pilot chamber. However, since the seal disc contacts the disc valve via the projection, the diameter of the contact portion between the disc valve and the seal disc is always constant, preventing variations in the valve opening pressure of the disc valve due to the internal pressure of the pilot chamber. And a stable damping force can be obtained.

According to the damping force adjusting type hydraulic shock absorber of the fifth aspect, the retainer disk is interposed between the disk valve and the seal disk, and the seal disk is provided near the outer peripheral end of the retainer disk. Even when the disk valve and the seal disk are bent due to an increase in the pressure in the pilot chamber due to the contact of the peripheral portion,
Since the diameter of the contact portion between the seal disk and the retainer disk hardly changes, a variation in the valve opening pressure of the disk valve with respect to the internal pressure of the pilot chamber can be prevented, and a stable damping force can be obtained.

According to the damping force adjusting hydraulic shock absorber of the sixth aspect, the seat member having the positioning projection, the first projection, and the second projection is interposed between the disk valve and the seal disk. Since the seat member abuts on the disc valve via the first protrusion, even if the disc valve and the seal disc are bent due to an increase in the pressure in the pilot chamber, the contact portion between the seat member and the disc valve is disturbed. Since the diameter is always constant, it is possible to prevent a variation in the valve opening pressure of the disc valve with respect to the internal pressure of the pilot chamber and to obtain a stable damping force. Further, the pressure in the pilot chamber can be applied to a portion on the inner peripheral side from the inner peripheral end of the seal disk of the disk valve by the first protrusion of the seat member, and the seat member has:
When the disc valve is opened, it moves in parallel along the axial direction. Therefore, when the disc valve is opened, the outer peripheral portion of the disc valve comes into contact with the center portion of the seal disc, and the seal disc is lifted from the outer seal portion. Therefore, the opening pressure of the disc valve with respect to the pressure of the pilot chamber can be set small, and the degree of freedom in setting the damping force characteristic can be increased.

[0098] Further, according to the damping force adjustable hydraulic shock absorber according to claim 7, the ratio of the inner diameter d _b of the inner diameter d _a and the outer seal portion of the valve seat disc valve was d _b / d _b ≦ 1.2 Thereby, the pressure receiving area of the seal disk with respect to the pilot chamber can be appropriately reduced, the pilot pressure acting on the disk valve can be optimized, and the damping force characteristics can be optimized.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a first embodiment of the present invention.

FIG. 2 is an enlarged view of the damping force generating mechanism of FIG.

FIG. 3 is a longitudinal sectional view of a damping force generation mechanism of a damping force adjusting type hydraulic shock absorber according to a second embodiment of the present invention.

FIG. 4 is an enlarged view showing a main damping valve and a pilot chamber of FIG. 3;

FIG. 5 is a longitudinal sectional view of a damping force generation mechanism of a damping force adjusting hydraulic shock absorber according to a third embodiment of the present invention.

FIG. 6 is an enlarged view showing a main damping valve and a pilot chamber in FIG. 5;

FIG. 7 is a longitudinal sectional view of a damping force generating mechanism of a damping force adjusting type hydraulic shock absorber according to a fourth embodiment of the present invention.

FIG. 8 is an enlarged view showing a main damping valve, a sub damping valve, and a pilot chamber in FIG. 7;

FIG. 9 is a view showing a damping force characteristic of a damping force adjustable hydraulic shock absorber according to a fourth embodiment of the present invention.

FIG. 10 is a longitudinal sectional view of a damping force adjusting type hydraulic shock absorber according to a fifth embodiment of the present invention.

11 is a longitudinal sectional view of a main part of the device of FIG.

FIG. 12 is an enlarged view of the main damping valve of the device of FIG.

FIG. 13 is a view showing deformation of the disc valve and the seal disc due to the internal pressure of the pilot chamber in the case where no projection is provided on the disc valve in the main damping valve of FIG. 12;

FIG. 14 is an enlarged longitudinal sectional view showing a main damping valve and a pilot chamber of a damping force adjusting type hydraulic shock absorber according to a sixth embodiment of the present invention.

FIG. 15 is an enlarged longitudinal sectional view showing a main damping valve and a pilot chamber of a damping force adjustable hydraulic shock absorber according to a seventh embodiment of the present invention.

FIG. 16 is an enlarged longitudinal sectional view showing a main damping valve and a pilot chamber of a damping force-adjustable hydraulic shock absorber according to an eighth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Damping force adjustable hydraulic shock absorber 2 Cylinder 5 Piston 6 Piston rod 26,27 Valve member 28,29 Seal member 34,35 Oil passage (main passage) 36,37 Inner seal part 38,39 Valve seat 40,41 Outer seal Part 42,43 Groove 46,47 Disc valve 48,49 Seal ring (outer seal part) 54,55 Seal disc 56,57 Valve spring (spring means, leaf spring) 56a, 57a Notch (oil passage) 58,59 Pilot chamber 64,65 Notch (fixed orifice) 66,67 Groove (upstream passage) 60,63 Port (downstream passage, variable orifice) 78,79 Sub disc valve (sub damping valve) 107 Projection 120,121 Retainer disc 125,126 Seat member 129,130 inner diameter S _1, S ₂ space positioning protrusions 131 and 132 protruding portions (first protruding portions) 133 and 134 projections (second projections) d _a disc inner diameter d _b retainer ring of the valve seat of the valve (the outer seal portion)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naoki Makita 1116 Koen, Ayase-shi, Kanagawa Inside Tokiko Sagami Plant

Claims (7)

[Claims] 1. A cylinder filled with an oil liquid, a piston slidably fitted in the cylinder, and a piston rod having one end connected to the piston and the other end extending to the outside of the cylinder. A main passage through which oil fluid flows by sliding of the piston; a main damping valve provided in the main passage to adjust a flow passage area of the main passage; and a main damping valve provided on a back surface of a valve element of the main damping valve. A pilot chamber for applying an internal pressure in the valve closing direction of the valve body, an upstream passage communicating the pilot chamber with the main passage upstream of the main damping valve, and a fixed member provided in the upstream passage. An orifice, a downstream passage for communicating the pilot chamber with a downstream side of the main damping valve of the main passage, and a variable orifice provided in the downstream passage and adjusting a flow passage area of the downstream passage. Damping force adjustable hydraulic shock absorber In the above, a bottomed cylindrical valve member, an oil passage penetrating the bottom of the valve member in the axial direction, an annular inner seal portion protruding from the inner wall of the bottom to the inner peripheral side of the oil passage, and the inner wall An annular valve seat protruding to the outer peripheral side of the oil passage, an annular outer seal part protruding to the outer peripheral side of the valve seat on the inner wall, and between the valve seat and the outer seal part on the inner wall. A groove to open,
A disk valve having an inner peripheral portion fixed to the inner seal portion and an outer peripheral portion abutting on the valve seat; and an annular seal having an inner peripheral portion abutting on a back surface portion of the disk valve and an outer peripheral portion abutting on the outer seal portion. A disc, a spring means for pressing the seal disc against the disc valve and the outer seal portion, and a seal member fitted into an opening of the valve member, wherein the oil passage and the groove constitute the main passage. And the disc valve constitutes a valve element of the main damping valve,
A damping force-adjustable hydraulic shock absorber, wherein the pilot chamber is defined by the side wall of the valve member, the disc valve, the seal disc, and the seal member. 2. The spring means is a disc-shaped leaf spring. The leaf spring has an oil passage for communicating a space formed by a disc valve, a seal disc and the leaf spring, and a pilot chamber with each other. The damping force adjustable hydraulic shock absorber according to claim 1, wherein the hydraulic shock absorber is provided. 3. A sub-attenuation valve, which opens upon receiving a pressure of an oil liquid flowing to a fixed orifice and generates a damping force having valve characteristics according to the opening degree.
Or the damping force adjustable hydraulic shock absorber according to 2. 4. The disk valve according to claim 1, wherein an annular projection is provided on a rear surface of the disk valve along a circumferential direction thereof, and an inner peripheral portion of the seal disk is brought into contact with the projection. The damping force adjustable hydraulic shock absorber according to any one of the above. 5. A disk-shaped retainer disk having a diameter slightly smaller than that of the disk valve is interposed between the disk valve and the seal disk, and the inner periphery of the seal disk is provided near an outer peripheral end of the retainer disk. The damping force-adjustable hydraulic shock absorber according to any one of claims 1 to 3, wherein the portions are in contact with each other. 6. An outer peripheral portion is formed with a positioning convex portion abutting on an outer peripheral surface of the disk valve, an annular first projection abutting on the disk valve is formed on one surface, and a seal is formed on the other surface. The damping force adjustment according to any one of claims 1 to 3, wherein an annular seat member having a second protrusion contacting the disk is interposed between the disk valve and the seal disk. Type hydraulic shock absorber. 7. claims 1, characterized in that the ratio of the inner diameter d _b of the inner diameter d _a and the outer seal portion of the valve seat disc valve was d _b / d _a ≦ 1.2 according to any one of 6 Hydraulic shock absorber with adjustable damping force.