JP7129385B2 - damping force adjustable shock absorber - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force adjustable shock absorber that controls the flow of working fluid accompanying the stroke of a piston rod to adjust damping force.

In Patent Document 1, when the expansion and contraction operation is exhibited, the hydraulic oil is always discharged from the inside of the cylinder through the discharge passage (annular passage) to the reservoir, and the hydraulic oil flows into the piston side chamber (cylinder lower chamber) and the rod side chamber (cylinder upper chamber). ), and a uniflow damping force adjustable shock absorber that circulates through the reservoir in a one-way fashion.

Japanese Patent No. 6130684

By the way, in vehicles developed in recent years, the rigidity of the vehicle body and the suspension device is increasing. Furthermore, there is a tendency for the diameter of the wheel to increase and the flatness of the tire to decrease. As a result, minute vibrations that could not be transmitted in the past were input to the damping force adjustable shock absorber at the very initial piston speed in the extremely low speed region when the piston started to move. The vibration generated at the piston speed in such a very low speed region deteriorates the ride comfort of the vehicle. However, the damping force responsiveness to the piston speed in the extremely low speed range was low, and it was difficult to control the damping force in the extremely low speed range.

An object of the present invention is to provide a damping force adjustable shock absorber capable of controlling the damping force in a very low speed range.

The damping force adjustable shock absorber of the present invention comprises an outer cylinder, a cylinder provided inside the outer cylinder and containing a working fluid, a piston slidably fitted in the cylinder, and one end of which is a piston rod connected to the piston and having the other end protruding outside the cylinder; a separator tube provided on the outer periphery of the cylinder; an annular oil passage formed between the separator tube and the cylinder; a reservoir formed between the outer cylinder and the separator tube; an opening provided in the side wall of the separator tube; a mounting hole provided in the outer cylinder so as to face the opening; a damping force adjusting mechanism for adjusting a damping force generated by controlling the flow of the working fluid between the annular oil passage and the reservoir; and an interior provided between the damping force adjusting mechanism and the opening. A damping force adjustable shock absorber comprising: a passage member serving as a passage between the annular oil passage and the damping force adjusting mechanism and having an external portion serving as a passage between the damping force adjusting mechanism and the reservoir The damping force adjustment mechanism includes a main valve that introduces a flow of working fluid accompanying movement of the piston through a main flow path provided in the passage member to generate a damping force; a pilot chamber for applying internal pressure in the valve closing direction; an introduction passage for introducing working fluid into the pilot chamber; a pilot passage for communicating the pilot chamber with a downstream side of the main valve; a pilot valve that discharges the working fluid from the pilot chamber by means of the a cylindrical portion fitted into the opening formed on one end side; and a contact surface provided on the other end side of the cylindrical portion against which the damping force adjusting mechanism contacts, wherein the valve mechanism is , a cylindrical screw having a flange portion at one end and a shaft portion at the other end; a screw communication passage formed in the screw; and a valve body for opening and closing the screw communication passage. In a region, the valve body is opened while the main valve is closed, and in a speed region higher than a low speed, the main valve and the valve body are opened.

According to the present invention, it is possible to provide a damping force adjustable shock absorber capable of controlling damping force in a very low speed range.

1 is a cross-sectional view of a damping force adjustable shock absorber according to a first embodiment; FIG. FIG. 2 is an enlarged view of a damping force adjustment mechanism in FIG. 1; 3 is an enlarged view of the valve mechanism in FIG. 2; FIG. 4 is a diagram showing damping force characteristics of the damping force adjustable shock absorber according to the first embodiment; FIG. It is an explanatory view of the second embodiment, and is a cross-sectional view of the damping force adjustment mechanism. FIG. 6 is an enlarged view of the valve mechanism in FIG. 5; FIG. 11 is an explanatory diagram of the third embodiment, and is a cross-sectional view of the damping force adjustment mechanism; FIG. 8 is an enlarged view of the valve mechanism in FIG. 7;

(First embodiment)
A first embodiment of the present invention will be described with reference to the accompanying drawings. For the sake of convenience, the vertical direction in FIG. 1 will be referred to as the "vertical direction" as it is. Moreover, the left side in FIG. 2 is called "one end side" and the right side is called "the other end side".

As shown in FIG. 1, the first embodiment relates to a so-called control-valve-mounted damping force adjusting hydraulic damping force adjusting shock absorber 1 in which a damping force adjusting mechanism 31 is laterally attached to the side wall of the outer cylinder 3. . The damping force adjustable shock absorber 1 has a double cylinder structure in which a cylinder 2 is provided inside an outer cylinder 3 , and a reservoir 4 is formed between the outer cylinder 3 and the cylinder 2 . A piston 5 that divides the inside of the cylinder 2 into two chambers, a cylinder upper chamber 2A and a cylinder lower chamber 2B, is slidably fitted in the cylinder 2 . A lower end (one end) of a piston rod 6 is connected to the piston 5 . The upper end side (other end) of the piston rod 6 passes through the cylinder upper chamber 2A, is inserted through the outer cylinder 3 and the rod guide 8 and the oil seal 9 attached to the upper end of the cylinder 2, and protrudes outside the cylinder 2. do.

The piston 5 is provided with passages 11 and 12 for communicating the cylinder upper chamber 2A and the cylinder lower chamber 2B. The compression-side passage 12 is provided with a check valve 13 that allows the working fluid to flow from the cylinder lower chamber 2B to the cylinder upper chamber 2A. On the other hand, the expansion-side passage 11 has a disk that opens when the pressure on the side of the cylinder upper chamber 2A reaches a set pressure, and relieves the pressure on the side of the cylinder upper chamber 2A to the side of the cylinder lower chamber 2B. A valve 14 is provided.

A base valve 10 that separates the cylinder lower chamber 2B and the reservoir 4 is provided at the lower end of the cylinder 2 . The base valve 10 is provided with passages 15 and 16 that communicate the cylinder lower chamber 2</b>B and the reservoir 4 . The extension-side passage 15 is provided with an extension-side disk valve 17 that allows the working fluid to flow from the reservoir 4 side to the cylinder lower chamber 2B side. On the other hand, the compression-side passage 16 has a compression-side disk that opens when the pressure on the side of the cylinder lower chamber 2B reaches a set pressure, and relieves the pressure on the side of the cylinder lower chamber 2B to the reservoir 4 side. A valve 18 is provided. As the working fluid, the cylinder 2 is filled with oil, and the reservoir 4 is filled with oil and gas.

As shown in FIG. 1, a separator tube 20 is attached to the outer periphery of the cylinder 2 via a pair of seal members 19,19. An annular oil passage 21 is formed between the separator tube 20 and the cylinder 2 . The annular oil passage 21 communicates with the cylinder upper chamber 2</b>A through a passage 22 provided in the upper end side wall of the cylinder 2 . A side wall of the separator tube 20 on the lower end side is provided with a cylindrical connection port 23 (opening) protruding sideways and having an open end. A side wall of the outer cylinder 3 is provided with a mounting hole 24 at a position facing the connection port 23 . The mounting hole 24 is arranged coaxially with the connection port 23 and has an inner diameter larger than the outer diameter of the connection port 23 . A substantially cylindrical case 25 surrounding the mounting hole 24 is provided on the side wall of the outer cylinder 3 . A damping force adjustment mechanism 31 is housed in the case 25 .

Referring to FIG. 2, the damping force adjustment mechanism 31 includes a back pressure type main valve 32, a pilot valve 33 that controls the valve opening pressure of the main valve 32, and a fail-safe valve 34 provided downstream of the pilot valve 33. A valve block 35 incorporated and integrated, and a solenoid block 40 incorporating a mechanism for operating the pilot valve 33 are provided.

The valve block 35 has a joint member 37 inserted through the mounting hole 24 . The joint member 37 includes a cylindrical cylindrical portion 38 whose one end side is inserted into the connection port 23 (opening), and a flange portion 39 (this part) formed on the other end side of the cylindrical portion 38 and inserted into the case 25. tangent) and The joint member 37 is covered with a seal member, thereby sealing the abutting portion between the connection port 23 and the main body 41 (seat member). The flow path 36 outside the valve block 35 (outside the damping force adjustment mechanism 31) and the reservoir 4 are communicated with each other by a plurality of passages 26 (grooves) provided in the bottom portion (inner flange portion) of the case 25. be. Also, the passage member is composed of the joint member 37 and the main body 41 .

The valve block 35 has an annular main body 41 , an annular pilot body 42 , and a pilot pin 43 connecting the main body 41 and the pilot body 42 together. The outer peripheral edge portion of the main body 41 on one end side contacts the outer peripheral edge portion of the flange portion 39 of the joint member 37 . An annular seat portion 45 (a seat surface of the main valve 32, a contact surface with which the damping force adjustment mechanism 31 abuts) is formed on the outer peripheral edge portion of the other end side (end surface) of the main body 41 . The outer peripheral portion of the main disk valve 47 (main valve 32 ) is seated on the seat portion 45 .

The inner peripheral edge of the main disc valve 47 is clamped between the large diameter portion 54 of the pilot pin 43 and the clamp portion 46 of the main body 41 . An annular packing 48 is fixed to the outer peripheral edge of the rear surface (the "right side" in FIG. 2) of the main disk valve 47 . An annular recess 52 is provided on the other end side of the main body 41 . As a result, the main disk valve 47 is seated on the seat portion 45 to form an annular passage 49 (valve chamber). On the other hand, a concave portion 50 is formed on one end side of the main body 41 . The recessed portion 50 and the annular recessed portion 52 (annular passage 49 ) on the other end side are communicated by a plurality of passages 51 .

The pilot pin 43 is formed in a bottomed cylindrical shape with the other end side open. An introduction orifice 53 is formed at the bottom of the pilot pin 43 on one end side. A large-diameter portion 54 is formed at an axially intermediate position of the pilot pin 43 . One end of the pilot pin 43 is press-fitted into the shaft hole 55 of the main body 41 . On the other hand, the other end side of the pilot pin 43 is press-fitted into the shaft hole 56 of the pilot body 42 . A plurality of grooves 58 extending in the axial direction (“horizontal direction” in FIG. 2) are formed in the outer peripheral surface of the pilot pin 43 on the other end side. A plurality of passages 57 (introduction passages) are formed between the pilot pin 43 and the pilot body 42 .

The pilot body 42 is formed in a substantially bottomed cylindrical shape with the other end side open. A flexible disk 59 clamped by the large diameter portion 54 of the pilot pin 43 is provided on one end side of the pilot body 42 . A cylindrical portion 60 coaxial with the pilot body 42 is formed on the outer peripheral edge portion of the pilot body 42 on one end side. The packing 48 of the main valve 32 is slidably brought into contact with the inner peripheral surface of the cylindrical portion 60 . Thereby, a pilot chamber 61 is formed on the back side of the main disk valve 47 . The pressure in the pilot chamber 61 acts on the main disk valve 47 (main valve 32) in the valve closing direction.

The pilot body 42 is formed with a plurality of passages 65 axially penetrating the bottom portion thereof. One end side (end surface) of the bottom portion of the pilot body 42 is provided with an annular seat portion (reference numeral omitted) on which the flexible disk 59 is seated. Between the bottom of the pilot body 42 and the flexible disk 59, an annular passageway (not numbered) is formed in which one end side of the passageway 65 is open. The flexible disk 59 bends under the internal pressure of the pilot chamber 61 to impart bulk elasticity to the pilot chamber 61 .

The flexible disc 59 is formed by laminating a plurality of discs, and a notch 66 is provided in the disc that contacts the large diameter portion 54 of the pilot pin 43 among the plurality of discs. The notch 66 communicates with the passage 57 between the pilot body 42 and the pilot pin 43 . The oil in the annular oil passage 21 is introduced into the damping force adjustment mechanism 31 via the connection port 23 (opening) and the flow path 63 in the joint member 37, and is introduced into the introduction passage, that is, the introduction orifice 53, the pilot pin, and the like. It is introduced into pilot chamber 61 via channel 44 of 43 , passage 57 and notch 66 .

A valve chamber 68 is formed inside the pilot body 42 . At the center of the bottom of the pilot body 42, an annular seat portion 69 (pilot valve) is provided at the opening peripheral edge of the shaft hole 56 on the other end side. A valve body 71 (pilot valve) provided in the valve chamber 68 is seated and separated from the seat portion 69 . The valve body 71 is formed in a substantially cylindrical shape, and has a tapered end portion on the side where the valve body 71 is seated and separated from the seat portion 69 . An outer flange-shaped spring receiving portion 72 is formed on the other end side of the valve body 71 . The valve body 71 is elastically supported by a pilot spring 73 , a fail-safe spring 74 and a fail-safe disk 79 so as to be axially movable (“horizontal direction” in FIG. 2 ) facing the seat portion 69 . Note that the pilot spring 73 and the failsafe spring 74 are formed as a single nonlinear spring.

A cylindrical portion 75 is formed on the other end side of the pilot body 42 , that is, on the side opposite to the cylindrical portion 60 side. The cylindrical portion 75 is formed with stepped portions 76 and 77 whose inner diameter increases stepwise toward the opening side (the other end side). An outer peripheral edge of the pilot spring 73 is supported by a stepped portion 76 . Fail-safe spring 74 , spacer 78 , fail-safe disk 79 , retainer 80 , spacer 81 , and washer 82 are fixed by cap 83 while overlapping stepped portion 77 . Between the cap 83 and the cylindrical portion 75 of the pilot body 42, a passage 84 is formed that communicates the valve chamber 68 with the passage 36 outside the valve block 35 (outside the passage member).

The solenoid block 40 is integrated with a coil 86 , cores 87 and 88 , a plunger 89 , and a hollow operating rod 90 connected to the plunger 89 in a solenoid case 85 . A spacer 92 and a cover 93 are inserted into the other end side of the solenoid case 85 , and axial force acts on the parts inside the solenoid case 85 by plastically working the periphery of the other end side of the solenoid case 85 . When the coil 86 is energized via the lead wire 94, the plunger 89 generates an axial thrust corresponding to the current value.

One end side of the solenoid case 85 is inserted through an opening on the other end side of the case 25 , and a seal member 95 seals between the solenoid case 85 and the case 25 . One end of the operating rod 90 protrudes into the valve chamber 68 and has a valve body 71 attached to the end. By tightening the nut 97 screwed to the case 25 and compressing the retaining ring 96 mounted in the annular groove, the solenoid case 85 and the case 25 are fixed, and the valve block 35 and the solenoid block 40 are coupled. be (unified).

When the coil 86 is not energized (the upper half of the axis in FIG. 2), the spring force of the fail-safe spring 74 causes the valve body 71 to move in the direction in which the valve body 71 leaves the seat ("rightward direction" in FIG. 2). .). As a result, the spring receiving portion 72 of the valve body 71 abuts (seats) on the fail-safe disk 79 . At this time, the pilot spring 73 is separated from the step portion 76 . On the other hand, when the coil 86 is energized (the lower half of the axis in FIG. 2), the operating rod 90 is biased in the seating direction of the valve body 71 ("leftward" in FIG. 2).

As a result, the pilot spring 73 contacts the stepped portion 76 and the valve body 71 is seated on the seat portion 69 against the spring force of the pilot spring 73 and the fail-safe spring 74 . The valve-opening pressure of the valve body 71 is controlled by changing the value of current applied to the coil 86 . When the pilot valve 33 is in the soft mode in which the current applied to the coil 86 is small, the spring force of the pilot spring 73 and the thrust of the plunger 89 are balanced, and the valve body 71 is separated from the seat portion 69 .

For convenience, the oil flow in the damping force adjustment mechanism 31 is roughly divided into a main flow and a pilot flow. The main flow is the flow of oil that flows through a main passage (main flow passage) that communicates the upstream side and the downstream side of the main valve 32 . The main passage includes a plurality of passages 51 of the main body 41 and an annular passage 49, and the oil introduced from the connection port 23 (opening) through the plurality of passages 51 into the annular passage 49 (valve chamber). , through the main valve 32 to the flow path 36 (outside the passage member).

On the other hand, the pilot flow includes the oil flowing through the introduction passage and the oil flowing through the pilot passage that communicates between the pilot chamber 61 and the flow path 36 on the downstream side of the main valve 32 (outside the valve block 35). liquid flow. The pilot passage includes the notch 66 of the flexible disk 59, the passage 57, the passage 44 of the pilot pin 43, the valve chamber 68, and the passage 84 of the cap 83, and is introduced into the pilot chamber 61 through the introduction passage. The resulting oil is discharged to the flow path 36 (outside the passage member).

The damping force adjustable shock absorber 1 allows oil (working fluid) introduced from the connection port 23 (opening) and the flow path 63 in the joint member 37 to flow into the main passage (main flow passage) and the pilot passage (introduction passage). It has a valve mechanism 101 that restricts the inflow of The valve mechanism 101 is provided upstream of the main flow (passage 51) and the pilot flow (introduction orifice 53). The valve mechanism 101 includes a very low speed valve 113 that can adjust the damping force at the piston speed in the very low speed region, that is, the piston speed at the very initial stage when the piston 5 starts to move ("0.002 m/s" in the first embodiment). (valve body).

Referring to FIGS. 2 and 3, the valve mechanism 101 has a substantially cylindrical screw 102 . A flange portion 103 is formed at one end of the screw 102 . The other end of the screw 102 is press-fitted into the shaft hole 55 of the main body 41 (seat member). An end face 104 on the other end side of the screw 102 contacts an end face 105 on the one end side of the pilot pin 43 . In this state, a gap is formed in the axial direction between the opening 106 of the joint member 37 (passage member) and the flange portion 103 of the screw 102 . In other words, the flow path 63 in the joint member 37 and the recessed portion 50 of the main body 41 communicate with each other via the annular flow path 107 formed by the gap. The inner diameter of the opening 106 of the joint member 37 is smaller than the outer diameter of the flange portion 103 of the screw 102 . Although the inner diameter of the opening 106 is smaller than the outer diameter of the flange 103 in the first embodiment, the outer diameter of the flange 103 may be smaller than the inner diameter of the opening 106. good.

An annular seat surface 109 is formed on the other end surface of the flange portion 103 of the screw 102 . A gap is formed in the axial direction between the seat surface 109 and the bottom surface 110 of the recess 50 of the main body 41 . For convenience, the cylindrical portion of the screw 102 press-fitted into the shaft hole 55 of the main body 41 will be referred to as a press-fit portion 111, and the cylindrical portion from the seat surface 109 of the flange portion 103 to the bottom surface 110 of the main body 41 will be referred to as a non-press-fit portion 112. called.

The extremely low-speed valve 113 consists of an annular disk valve. The non-press-fit portion 112 of the screw 102 is slidably inserted into the shaft hole 114 of the extremely low-speed valve 113 . The outer periphery of the very low speed valve 113 is supported by an annular valve support 115 formed on the bottom surface 110 of the recess 50 of the main body 41 . On the other hand, the inner peripheral edge portion of the extremely low-speed valve 113 abuts on the seat surface 109 of the screw 102 so as to be separable and seatable. When the extremely low-speed valve 113 is closed, that is, when the inner peripheral edge of the extremely low-speed valve 113 is seated on the seat surface 109 , the other end of the passage 51 opens to the inner peripheral side of the valve support portion 115 . A passageway 116 is formed. In other words, the passage 51 communicates the annular passage 116 on one end side of the main body 41 with the annular passage 49 on the other end side.

A plurality of notches 117 are formed in the inner periphery of the very low speed valve 113 at intervals in the circumferential direction. When the extremely low-speed valve 113 is closed, that is, when the inner peripheral edge of the extremely low-speed valve 113 abuts (closely contacts) the seat surface 109, an annular passage 118 (annular flow path) formed on the outer periphery of the flange portion 103 of the screw 102 107) and the annular passage 116 formed in the inner periphery of the valve support portion 115 are blocked. On the other hand, when the extremely low-speed valve 113 is opened, that is, when the inner peripheral edge of the extremely low-speed valve 113 separates from the seat surface 109 , the upstream annular passage 118 (annular flow passage 107 ) and the downstream The annular passage 116 on the side is communicated with.

The screw 102 is formed with a notch 119 (screw communication path) extending axially (“leftward” in FIG. 3) from the end face 104 . The notch 119 opens in the outer peripheral surface of the non-press-fitting portion 112 and communicates the annular passage 116 with the introduction orifice 53 . A bottom surface 110 of the main body 41 is provided with a radially extending groove 120 . The groove 120 opens to the notch 119 of the screw 102 on the inner peripheral side and opens to the passage 51 of the main valve 41 on the outer peripheral side. That is, the groove 120 communicates the notch 119 and the passage 51 . In other words, the valve mechanism 101 includes a cylindrical screw 102 having a flange portion 103 at one end and a shaft portion at the other end, a screw communication passage 119 formed in the screw 102, and a valve body for opening and closing the screw communication passage 119. and a very low speed valve 113 of .

When the extremely low-speed valve 113 is opened, the upstream annular passage 118 is formed between the seat surface 109 and the inner peripheral edge of the extremely low-speed valve 113 (annular gap), and the extremely low-speed valve Through the notch 117 of 113 and the groove 120 of the main body 41, it communicates with the passage 51 (main passage) of the main body 41, and through the passage 121, the notch 117, and the notch 119 of the screw 102. , and communicates with the introduction orifice 53 (introduction passage). In other words, the valve mechanism 101 controls the inflow of oil from the annular passage 118 (the flow path 63 and the annular flow path 107) into the main passage (main passage) and the introduction passage.

Next, operation of the first embodiment will be described with reference to FIG.
FIG. 4 is a diagram showing damping force characteristics in the soft mode of the damping force adjustable shock absorber 1 according to the first embodiment. It should be noted that the valve body 71 is separated from the seat portion 69 in the soft mode.

In the soft mode that generates damping force with soft characteristics, damping force (axial force) is generated due to the frictional force of the sliding portion in the friction region where the piston speed is from 0 to 0.002 m/s. When the piston speed reaches 0.002 m/s, the differential pressure between the upstream side (annular passage 118) and the downstream side (annular passage 116) of the extremely low-speed valve 113 in the damping force adjustment mechanism 31 becomes When the valve opening pressure 113 is reached, the inner peripheral edge of the very low speed valve 113 is separated from the seat surface 109 of the screw 102 and the very low speed valve 113 opens. As a result, in the extremely low speed region of the piston speed, a damping force with valve characteristics corresponding to the opening of the extremely low speed valve 113 is generated.

When the extremely low-speed valve 113 is opened, the oil that has flowed into the annular passage 118 through the connection port 23 (opening) and the annular passage 107 flows through the flow path 121, the notch 117 of the extremely low-speed valve 113, and the groove 120. It flows to the main passage (main flow path) through. That is, oil is introduced into the annular passage 49 via the passage 51 . On the other hand, the oil that has flowed into the annular passage 118 flows through the passage 121, the notch 117, and the notch 119 of the screw 102 into the introduction passage. That is, the oil is introduced into the pilot chamber 61 through the introduction orifice 53 .

In a very low speed range from when the extremely low speed valve 133 of the damping force adjustment mechanism 31 opens (saturates) until the main valve 32 opens, the introduction orifice 53 generates a damping force with orifice characteristics. In the low speed range after the main valve 32 of the damping force adjusting mechanism 31 is opened due to the pressure difference generated at the introduction orifice 53 of the damping force adjusting mechanism 31, the main valve 32 generates a damping force with valve characteristics. In the medium speed range of the piston speed, the check valve 13 (compression side) or the disk valve 14 (extension side) of the piston 5 opens to generate a damping force of valve characteristics.

Here, in the conventional uniflow damping force adjustable shock absorber, the damping force responsiveness to the piston speed in the extremely low speed region is low, and it is difficult to control the damping force in the extremely low speed region. For this reason, minute vibrations input to the damping force adjustable shock absorber are transmitted to the driver, causing deterioration in ride comfort.

On the other hand, in the first embodiment, one end side of the cylindrical portion 38 of the joint member 37 is fitted into the connection port 23 (opening), and the seat portion 45 on the other end side of the main body 41 (seat member) is used for damping force adjustment. It abuts against the main valve 32 of the mechanism 31 . A valve mechanism 101 is provided between the joint member 37 and the main body 41 to limit the inflow of oil (working fluid) into the main passage (main passage) and the introduction passage. The valve mechanism 101 is provided with a very low speed valve 113 that opens at a piston speed in a very low speed range (for example, "0.002 m/s").

When closed, the extremely low-speed valve 113 has an upstream connection port 23 (opening), a plurality of passages 51 (main passages) formed in the downstream main valve 41, and an introduction orifice formed in the pilot pin 43. 53 (introduction passage) is blocked, and when the valve is opened, the connection port 23 is communicated with the plurality of passages 51 and the introduction orifice 53 . As a result, it is possible to improve the damping force responsiveness in the very low speed region, and it is possible to generate a damping force with valve characteristics according to the opening of the very low speed valve 113 even in the very low speed region. As a result, it becomes possible to control the damping force in the extremely low speed range, and the ride comfort of the vehicle in the extremely low speed range can be improved.

In the first embodiment, the extremely low-speed valve 113 opens when the piston speed is 0.002 m/s. do. In short, it means that the valve opens in a piston speed range lower than a very low piston speed range.

(Second embodiment)
Next, a second embodiment will be described with reference to FIGS. 5 and 6. FIG. Here, differences from the first embodiment will be described. Note that the same designations and reference numerals are used for common parts with the first embodiment, and redundant explanations are omitted.

In the first embodiment, the outer peripheral edge of the extremely low speed valve 113 is supported by an annular valve support portion 115 formed in the main body 41 (seat member), and the inner peripheral edge of the extremely low speed valve 113 is supported by the screw 102. The valve mechanism 101 is configured by contacting the seat surface 109 formed on the flange portion 130 so as to be separable and seatable.

On the other hand, in the second embodiment, the inner peripheral edge of the extremely low speed valve 113 is supported by an annular valve support portion 115 formed on the inner peripheral edge of the main body (seat member), and the outer peripheral edge of the extremely low speed valve 113 is supported. A valve mechanism 131 is configured by bringing the peripheral portion into contact with an annular seat portion 132 formed on the outer peripheral portion of the flange portion 103 of the screw 102 so as to be separable and seatable.

The end surface of the screw 102 on the outer peripheral side of the flange portion 103 abuts on the recessed portion 50 of the main body 41 in a liquid-tight manner. The flange portion 103 of the screw 102 and the flange portion 39 of the joint member 37 face each other with a certain gap 139 in the axial direction. When the extremely low speed valve 113 is closed, that is, when the extremely low speed valve 113 is seated on the seat portion 132 , an annular passage 133 is formed on the inner peripheral side of the seat portion 132 . The annular passage 133 communicates with the flow path 63 inside the joint member 37 and the connection port 23 (opening) through a plurality of notches 134 provided in the flange portion 103 .

An annular flow path 135 is formed inside the recess 50 of the main body 41 and downstream of the extremely low-speed valve 113 . One end sides of a plurality of passages 51 (main passages) are opened to the annular flow passage 135 . Also, the annular flow path 135 communicates with the introduction orifice 53 (introduction passage) through a notch 136 formed in the valve support portion 115 and a notch 119 of the screw 102 . The outer diameter of the extremely low speed valve 113 is larger than the outer diameter of the annular seat portion 132 (seat surface) and smaller than the inner diameter of the recess 50 of the main body 41 . That is, a gap 137 is formed in the radial direction (“vertical direction” in FIG. 6) between the outer peripheral end surface of the extremely low-speed valve 113 and the recess 50 .

When the extremely low-speed valve 113 is opened, the upstream annular passage 133 includes a gap 137 between the extremely low-speed valve 113 and the recess 50 and a plurality of grooves 138 formed in the outer peripheral edge of the bottom surface 110 of the recess 50. and communicated with the passage 51 (main passage) of the main body 41 through the gap 137, the plurality of grooves 138, the annular passage 135, the notch 136, and the notch 119 of the screw 102. It communicates with the orifice 53 (introduction passage). In other words, the valve mechanism 131 controls the inflow of oil from the annular passage 133 (the connection port 23 and the flow path 63) into the main passage (main passage) and the introduction passage.

According to the second embodiment, effects equivalent to those of the first embodiment can be obtained.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS. 7 and 8. FIG. Here, differences from the first embodiment will be described. Note that the same designations and reference numerals are used for common parts with the first embodiment, and redundant explanations are omitted.

In the first embodiment, the screw 102 is press-fitted into the shaft hole 55 of the main body 41 and the non-press-fitting portion 112 of the screw 102 is slidably fitted into the shaft hole 114 of the extremely low-speed valve 113. is supported by an annular valve support portion 115 formed on the main body 41 (seat member), and the inner peripheral edge of the extremely low-speed valve 113 is supported by the seat surface 109 formed on the flange portion 130 of the screw 102. The valve mechanism 101 is constructed by contacting the valve mechanism 101 so that it can be seated and detached.

On the other hand, in the third embodiment, the valve mechanism 141 is provided on the inner periphery of the joint member 37 (cylindrical portion of the passage member). A screw 142 is press-fitted into an opening on one end side of the tubular portion 38 of the joint member 37 . The screw 142 is axially positioned with respect to the joint member 37 by bringing a flange portion 145 formed at one end thereof into contact with the opening edge of the joint member 37 . The screw 142 is formed with a shaft hole 146 that communicates the connection port 23 (opening) with the flow path 63 in the joint member 37 .

An annular seat portion 147 is formed on the periphery of the shaft hole 146 that opens to the end face of the screw 142 on the other end side. A valve chamber 148 is formed inside the seat portion 147 with the extremely low-speed valve 143 seated on the seat portion 147 . The outer diameter of the extremely low speed valve 143 is smaller than the inner diameter of the tubular portion 38 of the joint member 37 . That is, a gap 149 is formed in the radial direction (“vertical direction” in FIG. 8) between the outer peripheral side end surface of the extremely low-speed valve 143 and the cylindrical portion 38 . The extremely low-speed valve 143 is pressed against the seat portion 147 by a valve spring 150 provided inside the cylindrical portion 38 . The other end side of the valve spring 150 is received by a spring receiving portion 151 formed at the opening edge of the shaft hole 55 opening to the bottom surface 110 of the recess 50 of the main body 41 .

The extremely low-speed valve 143 opens when the differential pressure between the upstream side (valve chamber 148) and the downstream side (flow path 63) reaches the valve opening pressure. When the extremely low-speed valve 143 is opened, the upstream valve chamber 148 moves from the main body 41 through the gap 149 between the extremely low-speed valve 143 and the cylindrical portion 38 , the flow path 63 , and the recess 50 of the main valve 41 . It communicates with the passage 51 (main passage) and communicates with the introduction orifice 53 (introduction passage) through the gap 149 , the flow path 63 , the recess 50 , and the shaft hole 55 of the main valve 41 . In other words, the valve mechanism 141 controls the inflow of oil from the connection port 23 to the main passage (main passage) and the introduction passage.

According to 3rd Embodiment, the effect equivalent to 1st Embodiment mentioned above can be obtained.

1 damping force adjustable shock absorber, 2 cylinder, 3 outer cylinder, 4 reservoir, 5 piston, 6 piston rod, 20 separator tube, 21 annular oil passage, 23 opening (connection port), 24 mounting hole, 31 damping force adjusting mechanism , 32 main valve, 33 pilot valve, 37 joint member (passage member, cylindrical portion), 41 main body (passage member, seating member), 45 seat portion (contact surface), 51 passage (main flow passage), 53 introduction orifice (Introduction passage) 61 pilot chamber, 101 valve mechanism

Claims (4)

an outer cylinder;
a cylinder provided inside the outer cylinder and sealed with a working fluid;
a piston slidably fitted within the cylinder;
a piston rod having one end connected to the piston and the other end protruding outside the cylinder;
a separator tube provided on the outer periphery of the cylinder;
an annular oil passage formed between the separator tube and the cylinder;
a reservoir formed between the outer cylinder and the separator tube;
an opening provided in the side wall of the separator tube;
a mounting hole provided in the outer cylinder so as to face the opening;
a damping force adjustment mechanism attached to the mounting hole for adjusting a damping force generated by controlling the flow of the working fluid between the annular oil passage and the reservoir;
Provided between the damping force adjusting mechanism and the opening, the inside serves as a flow path between the annular oil passage and the damping force adjusting mechanism, and the outside serves as a passage between the damping force adjusting mechanism and the reservoir. A damping force adjustable shock absorber comprising a passage member serving as a flow passage,
The damping force adjustment mechanism is
a main valve that introduces a flow of working fluid accompanying movement of the piston through a main flow path provided in the passage member to generate a damping force;
a pilot chamber that applies internal pressure to the main valve in a valve closing direction;
an introduction passage for introducing working fluid into the pilot chamber;
a pilot passage communicating between the pilot chamber and the downstream side of the main valve;
a pilot valve provided in the pilot passage for discharging working fluid from the pilot chamber;
The passage member is provided with a valve mechanism that restricts the inflow of the working fluid into the main flow passage and the introduction passage,
The passage member has a cylindrical portion that is fitted into the opening formed on one end side, and a contact surface that is provided on the other end side of the cylindrical portion and contacts the damping force adjustment mechanism,
The valve mechanism has a cylindrical screw having a flange portion at one end and a shaft portion at the other end, a screw communication passage formed in the screw, and a valve body for opening and closing the screw communication passage,
A damping characterized in that in a region where the piston speed is low, the valve body is opened while the main valve is closed, and in a speed region greater than the low speed, the main valve and the valve body are opened. Force adjustable buffer. 2. The damping force adjustable shock absorber according to claim 1, wherein the valve mechanism is provided on the inner periphery of the tubular portion. The passage member includes a seat member forming a seat surface of the main valve, a cylindrical portion fitted into the opening formed at one end, and a seat member provided at the other end of the cylindrical portion. 3. The damping force adjustable shock absorber according to claim 1 or 2, further comprising a joint member having an abutment surface that makes contact with the joint member. 4. The damping force adjustable shock absorber according to claim 3, wherein the valve mechanism is provided between the joint member and the seat member.

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