JPH10246271A - Damping force adjustable hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To widen an adjusting range of a damping force characteristic, also obtain proper damping force at hard characteristic time, in a damping force adjustable hydraulic shock absorber. SOLUTION: By moving a piston in a cylinder, a flow of oil fluid generated between connection holes 35, 36 and between connection holes 36, 37 is controlled by main damping valves A1 , A2 and variable orifices B1 , B2 , damping force is generated. In accordance with a current flowing in an actuator 30, a spool 74 is moved, a flow path area of the variable orifice B1 , B2 is changed, an orifice characteristic is directly adjusted, also a pressure of pilot chambers 62, 63 is changed, a valve opening characteristic of the main damping valves A1 , A2 is changed, a valve characteristic is adjusted. In disk valves 52, 53, guide parts 64, 65 are formed, a jet flow of oil fluid at valve opening time is jetted at a jet angle so as to be along a peripheral part of valve sets 44, 45 toward a space between the valve seat 44, 45 and the guide part 64, 65, so as to reduce force acting in a valve closing direction, a proper characteristic is obtained at head characteristic time.

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 and a railway vehicle.

2. Description of the Related Art Hydraulic shock absorbers mounted on suspension systems of vehicles such as automobiles and railway vehicles are designed so that damping force can be appropriately adjusted according to road surface conditions, running conditions, etc. in order to improve ride comfort and steering stability. 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.
The piston section is provided with a main oil passage and a bypass passage for communicating the two chambers in the cylinder. The main oil passage is provided with a damping force generating mechanism comprising an orifice and a disc valve. The damping force adjusting valve for adjustment is provided. 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.

[0004] With this configuration, the damping force adjusting valve allows
By opening the bypass passage and reducing the flow resistance of the oil liquid between the two chambers in the cylinder, the damping force is reduced, and by closing the bypass passage and increasing the flow resistance between the two chambers, the damping force is reduced. Can be increased. 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 the passage area of the bypass passage as described above, the damping force greatly changes the damping force characteristic in a low piston speed range because the damping force depends on the orifice of the oil passage. However, in the middle and high speed range of the piston speed, the damping force characteristic cannot be largely changed because the damping force depends on the damping force generation mechanism (disk valve) of the main oil liquid passage.

Therefore, conventionally, for example, Japanese Utility Model Laid-Open No. Sho 62-155
As described in JP-A-242, a pilot chamber is formed at the back of a disk valve as a damping force generating mechanism for a main oil liquid passage provided in a piston portion, and this pilot chamber is connected to a disk valve via a fixed orifice. Is connected to a cylinder chamber on the upstream side of the disk valve and to a cylinder chamber on the downstream side of the disk valve via a variable orifice.

According to this damping force adjusting type hydraulic shock absorber, by opening and closing the variable orifice, the passage area between the two chambers in the cylinder is adjusted, and the pressure in the pilot chamber is changed by the pressure loss generated in the variable orifice. Thus, the valve opening pressure of the disc valve can be adjusted. In this way, the orifice characteristic (the damping force is approximately proportional to the square of the piston speed) and the valve characteristic (the damping force is approximately proportional to the piston speed) can be simultaneously adjusted, and the adjustment range of the damping force characteristic can be adjusted. Can be wider.

[0008]

However, the damping force adjusting type hydraulic shock absorber described in the above publication has the following problems. In this type of damping force adjusting type hydraulic shock absorber, the valve opening pressure of the disc valve is determined by the sum of its spring force and the load in the valve closing direction due to the pressure of the pilot chamber adjusted by the variable orifice. Therefore, when the damping force is adjusted to the hard side by reducing the flow path area of the variable orifice, the opening of the disc valve a decreases as shown in FIG. Since the gap with b becomes small, the flow rate of the oil liquid passing through this gap is increased to become the jet c. As a result, the static pressure in the gap between the disc valve a and the valve seat b decreases, and a force in the valve closing direction acts on the disc valve a to increase the damping force. As shown by a broken line therein, there is a problem that the inclination of the damping force characteristic after opening of the disk valve at the time of the hard characteristic becomes excessively large.

At this time, the force F acting on the disc valve a by the jet c in the valve closing direction is expressed by the following equation. F = −ρQv · cos θ ρ: density of oil liquid Q: flow rate v: flow velocity θ: jet angle of jet with respect to the axial direction of the disc valve Here, if F <0, the force F is in the valve closing direction. When F> 0, the force F acts in the valve opening direction. In the example shown in FIG. 7, the ejection direction of the jet c is theta ₀ angle with respect to the axial direction of the disk valve _{a (θ 0 <90 °,} co
s θ> 0. That is, F <0. ), The force in the valve closing direction due to the jet flow c acts on the disk valve a, making it difficult to open the valve.

[0010] The present invention has been made in view of the above points, and provides a damping force-adjustable hydraulic shock absorber that has a wide damping force adjustment range and can obtain appropriate damping force characteristics. With the goal.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a cylinder filled with an oil liquid, and two cylinder chambers slidably fitted in the cylinder. A piston, one end of which is connected to the piston and the other end of which extends to the outside of the cylinder, and a main passage through which the oil liquid flows by movement of the piston along with the stroke of the piston rod. A main damping valve that opens upon receiving the pressure of the oil liquid in the main passage to generate a damping force in accordance with the degree of opening, and a valve closing valve provided at the back of the valve body of the main damping valve A pilot chamber for applying an internal pressure in the direction, an upstream passage for communicating the pilot chamber with the main passage upstream of the main damping valve, and a downstream side of the pilot chamber and the main passage of the main damping valve. Downstream passage that communicates A damping force-adjustable hydraulic shock absorber comprising a fixed orifice provided in the upstream passage and a variable orifice provided in the downstream passage, wherein the main damping valve is annularly protruded. A valve seat, and a disc-shaped valve body seated on the valve seat, and an outer peripheral portion of the valve body is extended toward the valve seat to form a gap between the outer peripheral portion of the valve seat. A cylindrical guide portion is formed, and the jet of oil liquid when the valve body is opened is jetted toward a gap between the outer peripheral portion of the valve seat and the guide portion. It is characterized by.

With this configuration, the flow of the oil liquid generated in the main passage, the upstream passage and the downstream passage by the movement of the piston in accordance with the stroke of the piston rod is controlled by the main damping valve, the fixed orifice and the variable orifice. To generate damping force. Before the main damping valve is opened, damping force is generated according to the flow area of the fixed orifices and variable orifices in the upstream passage and the downstream passage. When the valve is opened, a damping force is generated according to the degree of opening. By adjusting the flow area of the variable orifice,
In addition to directly adjusting the flow passage area of the downstream passage, the valve opening characteristic of the main damping valve is adjusted by changing the pressure of the pilot chamber. The jet of the oil liquid when the main damping valve is opened is jetted toward the gap between the guide portion of the valve body and the valve seat at an jet angle along the outer peripheral portion of the valve seat.

[0013]

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 FIG. 2, the damping force-adjustable hydraulic shock absorber 1 according to the first embodiment has a double-cylinder structure in which an outer cylinder 3 is provided outside a cylinder 2. An annular reservoir 4 is formed therebetween. A piston 5 is slidably fitted in the cylinder 2, and the piston 5 defines the inside of the cylinder 2 into two cylinder chambers, an upper cylinder chamber 2a and a lower cylinder 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. 8 and the sealing member 9 extend to the outside of the cylinder 2. At the lower end of the cylinder 2, a base valve 10 that partitions the cylinder lower chamber 2b and the reservoir 4 is provided.
An oil liquid is sealed in the cylinder 2, and an oil liquid and a gas are sealed in the reservoir 4.

The piston 5 has an oil passage 11 communicating between the cylinder upper and lower chambers 2a and 2b, and a cylinder lower chamber 2b of the oil passage 11.
A check valve 12 is provided to allow the flow of the oil liquid from the side to the cylinder upper chamber 2a side. The base valve 10 has an oil passage 13 for communicating the cylinder lower chamber 2b with the reservoir 4, and a check valve 14 for permitting the flow of oil from the reservoir 4 side of the oil passage 13 to the cylinder lower chamber 2b. Is provided.

A substantially cylindrical passage member 15 is fitted around the outer periphery of the central portion of the cylinder 2. An upper tube 16 is fitted on the upper outer periphery of the cylinder 2 and connected to the passage member 15 to form an annular oil passage 17 with the cylinder 2. The annular oil passage 17 communicates with the cylinder upper chamber 2a via an oil passage 18 provided on a side wall near the upper end of the cylinder 2. A lower tube 19 is provided on the outer periphery of the lower part of the cylinder 2.
Are fitted and connected to the passage member 15, and the cylinder 2
To form an annular oil passage 20. The annular oil passage 20 communicates with the cylinder lower chamber 2b via an oil passage 21 provided on a side wall near the lower end of the cylinder 2.

A connection plate 22 is attached to the outer cylinder 3 so as to face the passage member 15. Connection pipes 23 and 24 communicating with the annular oil passages 17 and 20 are inserted and fitted into the connection plate 22 and the passage member 15, respectively. The connection plate 22 has a connection hole 25 communicating with the reservoir 4. The connecting plate 22 has a damping force generating mechanism 26
Is installed.

As shown in detail in FIG. 1, a damping force generating mechanism
Reference numeral 26 denotes a bottomed cylindrical case 27 in which two bottomed cylindrical valve members 28 and 29 are fitted, and a proportional solenoid actuator 30 (hereinafter, referred to as an actuator 30) is screwed into an opening of the case 27. The inside of the case 27 is partitioned into three oil chambers 27a, 27b, and 27c by valve members 28 and 29. The valve members 28 and 29 are fitted with annular fixing members 31 and 32 respectively in their openings, and a substantially cylindrical guide member 33 screwed to the actuator 30 is inserted therethrough. And are fixed together with them. Oil chambers 27a, 27b, 27c and connecting pipes 23, 24 are provided on the side wall of the case 27.
And oil passages 35, 36, and 37 that communicate with connection holes 25, respectively.
Is provided.

At the bottom of the valve members 28 and 29, a plurality (only two are shown) of oil passages 38 and 39 which are arranged along the circumferential direction respectively penetrate in the axial direction. Valve member 28, 29
Sub-disks having notches (orifices) 40a, 41a for controlling damping force by controlling the flow of the oil from the oil chambers 27a, 27b to the oil passages 38, 39, respectively, are provided at the outer ends of the bottom of the disk. Valves 40 and 41 are provided. Secondary disk valve 4
Numerals 0 and 41 are such that the inner peripheral side is opened. The auxiliary disc valves 40 and 41 are for obtaining an appropriate damping force in a low piston speed range, that is, in an orifice characteristic range.

Inside the bottoms of the valve members 28 and 29, annular inner seal portions are formed on the inner peripheral sides of the oil passages 38 and 39, respectively.
An annular valve seat 4 is provided on the outer peripheral side of the oil passages 38, 39.
4 and 45 are protruded, and the valve member 2 on the outer peripheral side is further provided.
Annular outer seal portions 46, 47 protrude near the side walls of 8, 29, respectively. Annular grooves 48, 49 are formed between the valve seats 44, 45 and the outer seals 46, 47, and the annular grooves 48, 49 are provided in oil passages 50 provided in the valve members 28, 29, respectively. , 51 to oil chambers 27b, 27c.

An outer peripheral portion of one end surface of each of annular disk valves 52, 53 (valve body) is seated on the valve seats 44, 45, and an annular seal is provided on an inner peripheral portion of the other end surface of each of the disk valves 52, 53. The inner peripheral portions of the disks 54 and 55 are in liquid-tight contact with each other, and the outer peripheral portions of the seal disks 54 and 55 are in liquid-tight contact with the outer seal portions 46 and 47 via spacer rings 56 and 57. . Further, the inner peripheral portion is provided with spacer rings 58,
The outer peripheral portions of the disc-shaped leaf springs 60 and 61 fixed via 59 are in contact with the inner peripheral portions of the seal discs 54 and 55 in a liquid-tight manner. Disc valve 5
2, 53 and seal disks 54, 55 are pressed toward the valve seats 44, 45. Then, the fixing members in the valve members 28 and 29
Pilot chambers 62, 63 are formed between 31, 31 and seal rings 54, 55 and leaf springs 60, 61, respectively.

The valve seats 44, 45, the disc valve 52,
53, seal disks 54 and 55, leaf springs 60 and 61, and pilot chambers 62 and 63 constitute extension-side and contraction-side main damping valves A ₁ and A ₂ , respectively.
The internal pressures of the pilot chambers 62 and 63 provided on the back of the disc valves 52 and 53 act in the valve closing directions of the disc valves 52 and 53.

As shown in detail in FIG.
52 and 53 have cylindrical guide portions 64 and 65 formed with their outer peripheral portions extending toward the valve members 28 and 29, respectively.
A gap is formed between the inner peripheral surfaces of the valve seats 64 and 65 and the outer peripheral surfaces of the valve seats 44 and 45. The inner peripheral surfaces of the guide portions 64 and 65 are formed in a tapered shape, and cooperate with the chamfered portions 66 and 67 on the outer peripheral portions of the valve seats 44 and 45, as shown in FIG. , 53 is directed between the valve seats 44, 45 and the guide portions 64, 65, that is, the outer peripheral portions of the valve seats 44, 45 with respect to the axial direction of the disc valves 52, 53. Spout angle θ ₁ along
It is designed to squirt. Also, disc valve
The inner peripheral portions of the 52 and 53 are extended to the opposite side to the guide portions 64 and 65 to form cylindrical positioning convex portions 68 and 69, respectively.
The positioning projections 68, 69 are fitted to the inner peripheral portions of the seal disks 54, 55, and are positioned in the radial direction.

A plurality of leaf springs 60 and 61 (3
Sheet springs are laminated, and notches 60a, 60a,
61a is provided. The oil passages 38, 39 of the valve members 28, 29 and the pilot chambers 62,
An upstream passage and a fixed orifice communicating with 63 are formed.

The pilot chamber 6 is provided on the side wall of the guide member 33.
Ports 70 and 71 and oil chamber 27b communicating with 2 and 63, respectively
, 27c are provided with ports 72, 73, respectively. The ports 70 and 72 allow the pilot chamber 62
Downstream of the oil chamber 27b of the extension-side main damping valve A ₁ a and the downstream side passage of the extension-side for communicating are formed, also port 71,
By 73, downstream passage of the compression-side communicating the downstream side of the oil chamber 27c of the compression-side main damping valve A ₂ pilot chamber 63 is formed. A spool 74 is slidably fitted in the guide member 33. The spool 74 and the port 70 constitute an extension-side variable orifice B ₁ , and the port 73 constitutes a contraction-side variable orifice B _2. The communication passage area between the ports 71 and 73 is adjusted simultaneously.

In the above configuration, the oil passage 18, the annular oil passage 1
7, connecting pipe 23, oil passage 35, oil chamber 27a, oil passage 38, annular groove 4
8, oil passage 50, oil chamber 27b, oil passage 36, connecting pipe 24, annular oil passage 20
The oil passage 21 forms an extension-side main passage that communicates between the cylinder upper and lower chambers 2a and 2b. In addition, oil passage 21,
The cylinder lower chamber 2b and the reservoir 4 are formed by the annular oil passage 20, the connection pipe 24, the oil passage 36, the oil chamber 27b, the oil passage 39, the annular groove 49, the oil passage 51, the oil chamber 27c, the oil passage 37, and the connection hole 25. A main passage on the contraction side is formed to communicate between the two.

The operation of the present embodiment having the above-described structure will be described below.

During the extension stroke of the piston rod 6, the check valve 12 of the piston 5 is closed with the movement of the piston 5, and the oil liquid in the cylinder upper chamber 2a is pressurized.
The oil flows to the oil passage 35 of the damping force generating mechanism 26 through the connection pipe 17 and the connecting pipe 23, and further flows from the oil passage 35 to the oil chamber 27 a, the notch 40 a (sub disc valve 40), the oil passage 38, the notch 60 a of the leaf spring 60, Cylinder lower chamber through pilot chamber 62, port 70, port 72, oil chamber 27b, oil passage 36, connection pipe 24, annular oil passage 20 and oil passage 21
Flow to 2b. At this time, the pressure in the cylinder upper chamber 2a side reaches the extension-side main valve opening pressure of the damping valve A _1, the extension-side main damping valve A ₁
Is opened, and the oil liquid flows from the oil passage 38 to the oil chamber 27b through the annular groove 48 and the oil passage 50. On the other hand, the amount of oil liquid that the piston rod 6 has withdrawn from inside the cylinder 2 flows from the reservoir 4 to the cylinder lower chamber 2b by opening the check valve 14 of the base valve 10.

[0029] Thus, during the extension stroke, the piston speed is low, before the opening extension-side main damping valve A ₁ is cutout 40a and the secondary disk flow passage area of the valve 40 and the notch 60a and the extension-side variable orifice B ₁ depending damping force of orifice characteristics is generated by the piston speed increases, the pressure in the upper cylinder chamber 2a side to open extension-side main damping valve a ₁ rises, the damping force of valve characteristics according to the degree of opening Occurs. Then, by adjusting the flow passage area of the extension-side variable orifice B ₁ by moving the spool 74 by the actuator 30, and at the same time adjusting the orifice characteristics directly, the pressure in the pilot chamber 62 (the extension-side main damping valve A ₁ disc The valve characteristic can be adjusted by changing the back pressure of the valve 52, and the adjustment range of the damping force characteristic can be widened.

During the contraction stroke of the piston rod 6, the check valve of the piston 5 is moved with the movement of the piston 5.
12 is opened and the oil liquid in the lower cylinder chamber 2b flows directly into the upper cylinder chamber 2a through the oil passage 11 so that the cylinder upper and lower chambers 2b are opened.
Since the pressures at 2a and 2b are substantially the same, no oil liquid flows between the oil passages 35 and 36 of the damping force generating mechanism 26. On the other hand, as the piston rod 6 enters the cylinder 2, the check valve 14 of the base valve 10 closes, and the oil liquid in the cylinder 2 is pressurized to the extent that the piston rod 6 enters, and the cylinder lower chamber 2 b
Through the oil passage 21, the annular oil passage 20, and the connection pipe 24 to the oil passage 36 of the damping force generating mechanism 26, and further from the oil passage 36 to the oil chamber 27.
b, notch 41a (sub disc valve 41), oil passage 39, leaf spring
61 notch 61a, pilot room 63, port 71, port 73,
The oil flows to the reservoir 4 through the oil chamber 27c, the oil passage 37, and the connection hole 25. At this time, the cylinder upper and lower chambers 2a, the pressure of 2b side reaches a valve opening pressure of the compression-side main damping valve A _2, compression-side main damping valve
A ₂ is open, flows annular groove 49 from the oil passage 39 through the oil passage 51 directly to the oil chamber 27c.

[0031] Thus, during the compression stroke, the piston speed is low, before the compression-side main damping valve A ₂ opening, the damping force of orifice characteristics is generated depending on the flow passage area of the compression-side variable orifice B _2, The piston speed increases, and the cylinder upper and lower chambers 2a,
When the pressure of 2b side to the contraction side main damping valve A ₂ opens rise, the damping force of valve characteristics is generated depending on the degree of opening. And
By adjusting the flow passage area of the compression-side variable orifice B ₂ by moving the spool 74 by the actuator 30, and at the same time adjusting the orifice characteristics directly, the pressure in the pilot chamber 63 (the compression-side main damping valve A ₂ disk valve 53 The back pressure) to adjust the valve characteristics.
The adjustment range of the damping force characteristic can be widened.

In this case, depending on the position of the spool 74, the flow path area between the ports 70 and 72 on the extension side and between the ports 71 and 73 on the contraction side is small when one is large and small when one is small. By arranging the lands of each port and the spool so that the other becomes larger at the time of the above, a combination of types 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 (Combination of the expansion side is soft and the compression side is hard).

The expansion-side and compression-side main damping valves A ₁ , A ₂
When the valve is opened, the valve seats 44, 45 and the disc valves 52, 53
As shown in FIG. 4, the jets of the oil liquid passing between the disc valves 52, 53 are guided by the guide portions 64, 65 of the disc valves 52, 53 and the chamfered portions 66, 67 of the valve seats 44, 45. A jet angle θ ₁ along the outer periphery of the valve seats 44 and 45 with respect to the axial direction of
(Almost θ ₁ = 180 °). Here, in the above equation, when the ejection angle θ exceeds 90 ° and approaches 180 °, cos θ approaches −1, so that cos θ <0, and the force F acting on the disc valves 52 and 53 increases. (F>
0). As a result, the force F acts in the valve opening direction, so that the force F acting in the valve closing direction of the disk valves 52 and 53 by the jet can be reduced. Therefore, the main damping valves A ₁ and A ₂ on the extension side and the contraction side at the time of the hard characteristic are easily opened particularly in a high-speed region of the piston speed.
Excessive increase in the slope of the damping force characteristic can be prevented,
Appropriate damping force characteristics as shown by the solid line in FIG. 8 can be obtained.

Next, a second embodiment of the present invention will be described with reference to FIGS. It should be noted that the second embodiment has the same configuration as that of the first embodiment except that the structures of the disc valves of the expansion-side and compression-side main damping valves A ₁ and A ₂ are different. Hereinafter, the same portions as those of the first embodiment are denoted by the same reference numerals, and only different portions will be described in detail.

In the damping force-adjustable hydraulic shock absorber of the second embodiment, as shown in FIG.
The disc valves 75 and 76 of A ₁ and A ₂ are provided with guide portions 64 and
On the side opposite to 65, the positioning protrusions 68 of the first embodiment,
Instead of 69, the thick part that comes into contact with the sealing disks 54 and 55
77 and 78 are formed extending. The inner peripheral portions of the disc-shaped positioning disks 79, 80 having a plurality of (four in the drawing) cutout portions 79a, 80a on the outer peripheral portion are formed by the inner sealing portions 42, 43 and the spacer rings 58, 59. The disc valve is fixed on the outer circumference of the positioning discs 79 and 80.
The disc valves 75 and 76 are positioned in the radial direction by slidably fitting the inner peripheral portions of the discs 75 and 76.

With this configuration, the oil liquid that has passed through the valve members 28 and 29 is supplied to the notches 79a and 80 of the positioning disks 79 and 80.
a, and can flow into the notches 60a, 61a of the leaf springs 60, 61 and the pilot chambers 62, 63, and the same operation and effect as in the first embodiment can be obtained.

The projection height of the positioning projections 68, 69 in the first embodiment is set lower than the thickness of the seal disks 54, 55, and processing accuracy is required. Since the seal disks 54 and 55 abut on the meat portions 77 and 78, the thickness control (processing) of the disk valves 75 and 76 is facilitated.

[0038]

As described above in detail, according to the damping force adjusting type hydraulic shock absorber of the present invention, the orifice characteristics are directly adjusted by adjusting the flow area of the variable orifice, and the internal pressure of the pilot chamber is adjusted. , The valve characteristics can be adjusted by adjusting the valve opening characteristics of the main damping valve, so that the adjustment range of the damping force characteristics can be widened. In addition, since the guide portion is formed on the valve body of the main damping valve, the jet of the oil liquid when the main damping valve is opened is directed to the outer peripheral portion of the valve seat toward the gap between the guide portion of the valve body and the valve seat. Since the jet is ejected at a jetting angle that follows, the force acting on the valve body in the valve closing direction by the jet can be reduced, and the damping force characteristic at the time of the hard characteristic is prevented from excessively increasing, and appropriate damping is prevented. Force characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged longitudinal sectional view showing a damping force generation mechanism of a damping force adjustable hydraulic shock absorber according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing the overall configuration of the damping force adjusting type hydraulic shock absorber according to the first embodiment of the present invention.

FIG. 3 is an enlarged view of a main damping valve on an extension side and a contraction side, which is a main part of FIG. 2;

FIG. 4 is a view showing a jet direction of a jet of oil liquid when the extension-side and contraction-side main damping valves of the apparatus shown in FIGS. 1 to 3 are opened.

FIG. 5 is an enlarged view of an expansion-side and compression-side main damping valve, which is a main part of a damping force-adjustable hydraulic shock absorber according to a second embodiment of the present invention.

FIG. 6 is a perspective view of a positioning disk of the extension-side and compression-side main damping valves of FIG. 5;

FIG. 7 is a view showing a jet direction of a jet of oil liquid when a conventional disc valve is opened.

FIG. 8 is a diagram showing a damping force characteristic on a hardware side of the damping force adjusting type hydraulic shock absorber of the related art and the present invention.

[Explanation of symbols]

1 damping force adjustable hydraulic shock absorber 2 cylinder 2a upper cylinder chamber 2b lower cylinder chamber 5 piston 6 piston rod 44,45 valve seat 52,53 disk valve (valve element) 60a, 61a notch (upstream passage, fixed orifice) 62 , 63 Pilot chamber 64,65 Guide 70,71,72,73 Port (downstream passage) A ₁ Retraction-side main damping valve A ₂ Retraction-side main damping valve B ₁ Retraction-side variable orifice B ₂ Retraction-side variable orifice θ ₁ Spout angle

Claims (1)

[Claims] 1. A cylinder filled with an oil liquid, a piston slidably fitted in the cylinder and defining two cylinder chambers in the cylinder, one end connected to the piston and the other end connected to the piston. A piston rod extended to the outside of the cylinder, and a main passage through which an oil liquid flows by movement of the piston with a stroke of the piston rod;
A main damping valve that is opened by receiving the pressure of the oil liquid in the main passage and generates a damping force according to the degree of opening, and a valve closing direction of the valve body provided at a back of the valve body of the main damping valve A pilot chamber for applying an internal pressure to an upstream passage for communicating the pilot chamber with the upstream of the main damping valve of the main passage, and a downstream side of the main damping valve of the pilot chamber and the main passage. A downstream passage to be communicated, a fixed orifice provided in the upstream passage, and a damping force-adjustable hydraulic shock absorber including a variable orifice provided in the downstream passage, wherein the main damping valve is An annularly protruding valve seat, and a disc-shaped valve body seated on the valve seat, wherein an outer peripheral portion of the valve body extends to the valve seat side and is connected to an outer peripheral portion of the valve seat. A cylindrical guide portion that forms a gap therebetween is formed, and the jet flow of the oil liquid when the valve body is opened is formed. A damping force-adjustable hydraulic shock absorber, which is configured to blow out toward a gap between an outer peripheral portion of the valve seat and the guide portion.