JP2021021437A - Attenuation force adjustment-type shock absorber - Google Patents

Abstract

To provide an attenuation force adjustment-type shock absorber which can control an attenuation force in an extremely-low speed area.SOLUTION: A valve mechanism 101 for limiting the flow-in of a working fluid to a main flow passage and an introduction passage is arranged between a joint member 37 and a main body 41. An extremely-low speed valve 113 which is valve-opened at a piston speed in an extremely-low speed area is arranged at the valve mechanism 101. By this constitution, the responsiveness of an attenuation force in the extremely-low speed area can be enhanced, and the attenuation force of a valve characteristic corresponding to an opening of the extremely-low speed valve 113 can be generated even in the extremely-low speed area. As a result, the attenuation force in the extremely-low speed area can be controlled.SELECTED DRAWING: Figure 3

Description

The present invention relates to a damping force adjusting shock absorber that adjusts the damping force by controlling the flow of the working fluid accompanying the stroke of the piston rod.

According to Patent Document 1, when the expansion and contraction operation is exhibited, the hydraulic oil is always discharged from the cylinder to the reservoir through the discharge passage (annular passage), and the hydraulic oil is discharged to the piston side chamber (cylinder lower chamber) and the rod side chamber (cylinder upper chamber). ), A uniflow type damping force adjustment type shock absorber that circulates the reservoir in one way in order is disclosed.

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. Further, the diameter of the wheel tends to increase and the flatness of the tire tends to decrease. As a result, minute vibrations that have not been transmitted in the past at the piston speed in the extremely early extremely low speed range when the piston starts to move are input to the damping force adjustment type shock absorber. The vibration generated at the piston speed in such a very low speed range deteriorates the riding comfort of the vehicle. However, the damping force response to the piston speed in the extremely low speed range is low, and it is difficult to control the damping force in the extremely low speed range.

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

The damping force adjustment type shock absorber of the present invention has an outer cylinder, a cylinder provided inside the outer cylinder in which a working fluid is sealed, a piston slidably fitted in the cylinder, and one end thereof. A piston rod connected to the piston and the other end projecting to the outside of 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, and the above. 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, and mounting in the mounting hole. A damping force adjusting mechanism that controls the flow of the working fluid between the annular oil passage and the reservoir to adjust the damping force generated, and an internal cylinder provided between the damping force adjusting mechanism and the opening. A damping force adjusting shock absorber comprising a passage member that serves as a flow path between the annular oil passage and the damping force adjusting mechanism and a flow path between the damping force adjusting mechanism and the reservoir on the outside. Therefore, the damping force adjusting mechanism introduces a flow of working fluid accompanying the movement of the piston through a main flow path provided in the passage member to generate a damping force, and the main valve. 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 connecting the pilot chamber and the downstream side of the main valve, and the pilot passage are provided. A piston valve for discharging the working fluid of the pilot chamber is provided, and the passage member is provided with a valve mechanism for limiting the inflow of the working fluid into the main flow path and the introduction passage. The valve mechanism has a cylinder portion fitted to the opening formed on one end side and a contact surface provided on the other end side of the cylinder portion to which the damping force adjusting mechanism abuts. A cylindrical screw having a flange portion at one end and a shaft portion at the other end, a screw passage formed in the screw, and a valve body for opening and closing the screw passage, and the piston speed is low. The region is characterized in that the valve body is opened in a state where the main valve is closed, and the main valve and the valve body are opened in a speed region higher than a low speed.

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

It is sectional drawing of the damping force adjustment type shock absorber which concerns on 1st Embodiment. It is an enlarged view of the damping force adjusting mechanism in FIG. It is an enlarged view of the valve mechanism in FIG. It is a diagram which shows the damping force characteristic of the damping force adjustment type shock absorber which concerns on 1st Embodiment. It is explanatory drawing of 2nd Embodiment, and is sectional drawing of the damping force adjusting mechanism. It is an enlarged view of the valve mechanism in FIG. It is explanatory drawing of 3rd Embodiment, and is sectional drawing of the damping force adjusting mechanism. It is an enlarged view of the valve mechanism in FIG. 7.

(First Embodiment)
This will be described with reference to the figure attached with the first embodiment of the present invention. For convenience, the vertical direction in FIG. 1 is referred to as the "vertical direction" as it is. Further, the left side in FIG. 2 is referred to as "one end side" and the right side is referred to as "other end side".

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

The piston 5 is provided with passages 11 and 12 for communicating the cylinder upper chamber 2A and the cylinder lower chamber 2B. A check valve 13 that allows the flow of working fluid from the cylinder lower chamber 2B to the cylinder upper chamber 2A is provided in the passage 12 on the contraction side. On the other hand, in the extension side passage 11, a valve is opened when the pressure on the cylinder upper chamber 2A side reaches the set pressure, and the pressure on the cylinder upper chamber 2A side is released (released) to the cylinder lower chamber 2B side. A valve 14 is provided.

At the lower end of the cylinder 2, a base valve 10 for partitioning the cylinder lower chamber 2B and the reservoir 4 is provided. The base valve 10 is provided with passages 15 and 16 for communicating the cylinder lower chamber 2B and the reservoir 4. The extension-side passage 15 is provided with an extension-side disc valve 17 that allows the flow of working fluid from the reservoir 4 side to the cylinder lower chamber 2B side. On the other hand, in the passage 16 on the contraction side, a valve is opened when the pressure on the cylinder lower chamber 2B side reaches the set pressure, and the pressure on the cylinder lower chamber 2B side is relieved (missed) to the reservoir 4 side. A valve 18 is provided. As the working fluid, an oil liquid is sealed in the cylinder 2, and an oil liquid and a gas are sealed in the reservoir 4.

As shown in FIG. 1, a separator tube 20 is attached to the outer periphery of the cylinder 2 via a pair of sealing members 19 and 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 2A by a passage 22 provided on the side wall on the upper end side of the cylinder 2. A cylindrical connection port 23 (opening) is provided on the side wall on the lower end side of the separator tube 20 so as to project laterally and open the tip. A mounting hole 24 is provided on the side wall of the outer cylinder 3 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. The damping force adjusting mechanism 31 is housed in the case 25.

Referring to FIG. 2, the damping force adjusting mechanism 31 includes a back pressure type main valve 32, a pilot valve 33 for controlling the valve opening pressure of the main valve 32, and a fail-safe valve 34 provided on the downstream side of the pilot valve 33. It includes a valve block 35 that is incorporated and integrated, and a solenoid block 40 that incorporates a mechanism for operating the pilot valve 33.

The valve block 35 has a joint member 37 that is inserted into the mounting hole 24. The joint member 37 has a cylindrical tubular portion 38 whose one end side is inserted into the connection port 23 (opening) and a flange portion 39 (which is formed on the other end side of the tubular portion 38 and inserted into the case 25). Contact surface) and. The joint member 37 is covered with a sealing member, whereby the contact portion between the connection port 23 and the main body 41 (seat member) is sealed. The flow path 36 on the outside of the valve block 35 (outside the damping force adjusting mechanism 31) and the reservoir 4 are communicated with each other by a plurality of passages 26 (grooves) provided at the bottom (inner flange portion) of the case 25. To. Further, the passage member includes a joint member 37 and a main body 41.

The valve block 35 has an annular main body 41, an annular pilot body 42, and a pilot pin 43 that connects the main body 41 and the pilot body 42. The outer peripheral edge portion on one end side of the main body 41 comes into contact with the outer peripheral edge portion of the flange portion 39 of the joint member 37. An annular seat portion 45 (seat surface of the main valve 32, contact surface with which the damping force adjusting 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 edge of the main disc 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 back surface (“right side surface” in FIG. 2) of the main disc valve 47. An annular recess 52 is provided on the other end side of the main body 41. As a result, the main disc valve 47 is seated on the seat portion 45, so that the annular passage 49 (valve chamber) is formed. On the other hand, a recess 50 is formed on one end side of the main body 41. The recess 50 and the annular recess 52 (annular passage 49) on the other end side are communicated with each other by a plurality of passages 51.

The pilot pin 43 is formed in a bottomed cylindrical shape with the other end 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 side 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 on 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 open. A flexible disc 59 clamped by a 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 on one end side of the pilot body 42. The packing 48 of the main valve 32 is slidably contacted with the inner peripheral surface of the cylindrical portion 60. As a result, the pilot chamber 61 is formed on the back side of the main disc valve 47. The pressure in the pilot chamber 61 acts on the main disc valve 47 (main valve 32) in the valve closing direction.

The pilot body 42 is formed with a plurality of passages 65 that penetrate the bottom portion in the axial direction. An annular seat portion (reference numeral omitted) on which the flexible disc 59 is seated is provided on one end side (end face) of the bottom portion of the pilot body 42. An annular passage (reference numeral omitted) is formed between the bottom of the pilot body 42 and the flexible disc 59 so that one end side of the passage 65 opens. The flexible disk 59 bends under the internal pressure of the pilot chamber 61 to impart volume elasticity to the pilot chamber 61.

The flexible disk 59 is formed by stacking a plurality of disks, and the notch 66 is provided in the disk that contacts the large diameter portion 54 of the pilot pin 43 among the plurality of disks. The notch 66 communicates with a passage 57 between the pilot body 42 and the pilot pin 43. Then, the oil liquid in the annular oil passage 21 is introduced into the damping force adjusting 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. It is introduced into the pilot chamber 61 via the flow path 44, the passage 57, and the notch 66 of the 43.

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) formed on the peripheral edge of the opening on the other end side of the shaft hole 56 is provided. A valve body 71 (pilot valve) provided in the valve chamber 68 is taken off and seated on the seat portion 69. The valve body 71 is formed in a substantially cylindrical shape, and the end portion on the side to be detached and seated on the seat portion 69 is formed in a tapered shape. 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 the pilot spring 73, the fail-safe spring 74, and the fail-safe disc 79 so as to be movable in the axial direction (“horizontal direction” in FIG. 2) facing the seat portion 69. The pilot spring 73 and the fail-safe spring 74 are formed as a single non-linear 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, 77 whose inner diameter gradually increases toward the opening side (the other end side). The outer peripheral edge of the pilot spring 73 is supported by the step 76. The fail-safe spring 74, spacer 78, fail-safe disc 79, retainer 80, spacer 81, and washer 82 are fixed by the cap 83 in a state of being overlapped with the step portion 77. A flow path 84 is formed between the cap 83 and the cylindrical portion 75 of the pilot body 42 to communicate the valve chamber 68 and the flow path 36 outside the valve block 35 (outside the passage member).

The solenoid block 40 is a solenoid case 85 in which a coil 86, cores 87, 88, a plunger 89, and a hollow operating rod 90 connected to the plunger 89 are incorporated and integrated. A spacer 92 and a cover 93 are inserted into the other end side of the solenoid case 85, and an axial force acts on the parts inside the solenoid case 85 by plastic working the other end side peripheral portion of the solenoid case 85. When the plunger 89 energizes the coil 86 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 the opening on the other end side of the case 25, and the solenoid case 85 is sealed between the solenoid case 85 and the case 25 by a sealing member 95. One end side of the operating rod 90 projects into the valve chamber 68, and the valve body 71 is attached to the end portion. When the nut 97 screwed into the case 25 is tightened to compress 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 combined. (Integrated).

When the coil 86 is de-energized (upper half of the axis in FIG. 2), the valve body 71 is subjected to the spring force of the fail-safe spring 74 in the seating direction (“right direction” in FIG. 2). .) Is urged. As a result, the spring receiving portion 72 of the valve body 71 comes into contact (seat) with the fail-safe disc 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 (lower half of the axis in FIG. 2), the operating rod 90 is urged in the seating direction of the valve body 71 (“left direction” in FIG. 2).

As a result, the pilot spring 73 comes into contact with the step portion 76, and the valve body 71 is seated on the seat portion 69 against the spring forces 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 the current applied to the coil 86. In the soft mode in which the current value of energizing the coil 86 is small, the pilot valve 33 is in a state where 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 flow of oil and liquid in the damping force adjusting mechanism 31 is roughly divided into a main flow and a pilot flow. The main flow is a flow of oil and liquid flowing through a main passage (main flow path) that communicates between the upstream side and the downstream side of the main valve 32. The main passage includes a plurality of passages 51 and an annular passage 49 of the main body 41, and oil liquid introduced into the annular passage 49 (valve chamber) from the connection port 23 (opening) via the plurality of passages 51. , Discharge to the flow path 36 (outside the passage member) via the main valve 32.

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

The damping force adjusting type shock absorber 1 enters the main passage (main flow path) and the pilot passage (introduction passage) of the oil liquid (working liquid) introduced from the connection port 23 (opening) and the flow path 63 in the joint member 37. A valve mechanism 101 for limiting the inflow of The valve mechanism 101 is provided on the upstream side of the main flow (passage 51) and the pilot flow (introduction orifice 53). The valve mechanism 101 is an extremely low speed valve 113 capable of adjusting the piston speed in the extremely low speed range, that is, the damping force at the extremely initial piston speed (“0.002 m / s” in the first embodiment) when the piston 5 starts to move. (Valve body) is provided.

With reference 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). The end face 104 on the other end side of the screw 102 is in contact with the 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 103 of the screw 102. In other words, the flow path 63 in the joint member 37 and the recess 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 103 of the screw 102. In the first embodiment, the inner diameter of the opening 106 is smaller than the outer diameter of the flange 103, but 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 that is press-fitted into the shaft hole 55 of the main body 41 is 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 is referred to as a non-press-fit portion 112. Refer to.

The ultrafine low speed valve 113 comprises an annular disc valve. The non-press-fitted portion 112 of the screw 102 is slidably inserted into the shaft hole 114 of the ultrafine low-speed valve 113. The outer peripheral edge of the ultrafine low speed valve 113 is supported by an annular valve support portion 115 formed on the bottom surface 110 of the recess 50 of the main body 41. On the other hand, the inner peripheral edge of the ultra-fine low-speed valve 113 abuts on the seat surface 109 of the screw 102 so as to be able to take off and seat. When the ultra-micro low-speed valve 113 is closed, that is, when the inner peripheral edge of the ultra-micro low-speed valve 113 is seated on the seat surface 109, an annular shape in which the other end side of the passage 51 opens on the inner peripheral side of the valve support portion 115. A passage 116 is formed. In other words, the passage 51 communicates with the annular passage 116 on one end side of the main body 41 and the annular passage 49 on the other end side.

A plurality of notches 117 provided at intervals in the circumferential direction are formed on the inner peripheral edge of the ultrafine low-speed valve 113. When the ultra-fine low-speed valve 113 is closed, that is, when the inner peripheral edge portion of the ultra-fine low-speed valve 113 abuts (closely adheres) to the seat surface 109, the annular passage 118 (annular passage 118) formed on the outer periphery of the flange portion 103 of the screw 102. The communication between 107) and the annular passage 116 formed on the inner circumference of the valve support portion 115 is cut off. On the other hand, when the ultra-micro low-speed valve 113 is opened, that is, when the inner peripheral edge of the ultra-micro low-speed valve 113 is separated from the seat surface 109, the annular passage 118 (annular aisle 107) on the upstream side and the downstream side are passed through the notch 117. It communicates with the annular passage 116 on the side.

The screw 102 is formed with a notch 119 (screw continuous passage) extending in the axial direction (“left direction” in FIG. 3) from the end face 104. The notch 119 opens on the outer peripheral surface of the non-press-fitted portion 112 and communicates the annular passage 116 with the introduction orifice 53. A groove 120 extending in the radial direction is provided on the bottom surface 110 of the main body 41. The inner peripheral side of the groove 120 opens in the notch 119 of the screw 102, and the outer peripheral side opens in the passage 51 of the main valve 41. That is, the groove 120 communicates the notch 119 and the passage 51. In other words, the valve mechanism 101 serves as a valve body that opens and closes a cylindrical screw 102 having a flange portion 103 at one end and a shaft portion at the other end, a screw passage 119 formed in the screw 102, and a screw passage 119. It has a very low speed valve 113 and.

When the ultra-micro low-speed valve 113 is opened, the annular passage 118 on the upstream side is a flow path 121 (annular gap) formed between the seat surface 109 and the inner peripheral edge of the ultra-micro low-speed valve 113, and the ultra-micro low-speed valve. It is communicated with the passage 51 (main passage) of the main body 41 through the notch 117 of 113 and the groove 120 of the main body 41, and also through the notch 119 of the flow path 121, the notch 117, and the screw 102. It is communicated with the introduction orifice 53 (introduction passage). In other words, the valve mechanism 101 controls the inflow of oil liquid from the annular passage 118 (flow path 63 and annular passage 107) to the main passage (main passage) and the introduction passage.

Next, the operation of the first embodiment will be described with reference to FIG.
FIG. 4 is a diagram showing the damping force characteristics of the damping force adjusting buffer 1 according to the first embodiment in the soft mode. In the soft mode, the valve body 71 is separated from the seat portion 69.

In the soft mode in which the damping force of the soft characteristic is generated, the damping force (axial force) due to the frictional force of the sliding portion is generated 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 ultra-micro low-speed valve 113 in the damping force adjusting mechanism 31 is the micro-low speed valve. When the valve opening pressure of 113 is reached, the inner peripheral edge of the ultra-micro low-speed valve 113 separates from the seat surface 109 of the screw 102, and the ultra-micro low-speed valve 113 opens. As a result, in the extremely low speed range of the piston speed, a damping force of valve characteristics corresponding to the opening degree of the extremely low speed valve 113 is generated.

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

In the very low speed region from the opening (saturation) of the extremely low speed valve 133 of the damping force adjusting mechanism 31 to the opening of the main valve 32, the damping force of the orifice characteristic by the introduction orifice 53 is generated. Then, in the low speed region 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 damping force of the valve characteristics by the main valve 32 is generated. In the medium speed range of the piston speed, the check valve 13 (contraction side) or the disc valve 14 (extension side) of the piston 5 opens to generate a damping force of valve characteristics.

Here, in the conventional uniflow type damping force adjustment type shock absorber, the damping force response to the piston speed in the extremely low speed range is low, and it is difficult to control the damping force in the extremely low speed range. For this reason, minute vibrations input to the damping force adjustment type shock absorber are transmitted to the driver, which causes deterioration of riding comfort.

On the other hand, in the first embodiment, one end side of the tubular 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) adjusts the damping force. It comes into contact with the main valve 32 of the mechanism 31. A valve mechanism 101 that limits the inflow of oil (working fluid) into the main passage (main flow path) and the introduction passage is provided between the joint member 37 and the main body 41. The valve mechanism 101 is provided with an extremely low speed valve 113 that opens at a piston speed in the extremely low speed range (for example, "0.002 m / s").

When the ultra-low speed valve 113 is closed, the connection port 23 (opening) on the upstream side, a plurality of passages 51 (main passage) formed in the main valve 41 on the downstream side, and an introduction orifice formed in the pilot pin 43 are provided. The communication with the 53 (introduction passage) is cut off, 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 enhance the damping force responsiveness in the extremely low speed region, and it is possible to generate the damping force of the valve characteristics according to the opening degree of the extremely small low speed valve 113 even in the extremely low speed region. As a result, the damping force in the extremely low speed range can be controlled, and the riding comfort of the vehicle in the extremely low speed range can be improved.

In the first embodiment, when the piston speed is 0.002 m / s, the ultrafine low speed valve 113 is opened, but depending on the tuning, the valve is opened at 0.001 m / s or 0.005 m / s. To do. In short, it means that the valve is opened in the piston speed range lower than the very low speed range of the piston speed.

(Second Embodiment)
Next, the second embodiment will be described with reference to FIGS. 5 and 6. Here, the differences from the first embodiment will be described. For the parts common to the first embodiment, the same names and symbols will be used, and duplicate description will be omitted.

In the first embodiment, the outer peripheral edge portion of the ultrafine low speed valve 113 is supported by the annular valve support portion 115 formed on the main body 41 (seat member), and the inner peripheral edge portion of the ultrafine low speed valve 113 is supported by the screw 102. The valve mechanism 101 was formed by abutting the seat surface 109 formed on the flange portion 130 so as to be able to take off and seat.

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

The outer peripheral end surface of the flange portion 103 of the screw 102 is liquid-tightly contacted with the recess 50 of the main body 41. The flange portion 103 of the screw 102 and the flange portion 39 of the joint member 37 face each other with a constant gap 139 in the axial direction. When the ultra-fine low-speed valve 113 is closed, that is, when the ultra-fine 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) via 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 on the downstream side of the ultrafine low speed valve 113. One end side of a plurality of passages 51 (main passages) opens in the annular passage 135. Further, the annular flow path 135 communicates with the introduction orifice 53 (introduction passage) through the notch 136 formed in the valve support portion 115 and the notch 119 of the screw 102. The outer diameter of the ultrafine 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 end face on the outer peripheral side of the ultrafine low-speed valve 113 and the recess 50.

When the microlow speed valve 113 is opened, the annular passage 133 on the upstream side has a gap 137 between the microlow 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. In addition to being communicated with the passage 51 (main passage) of the main body 41, the introduction is made through the gap 137, a plurality of grooves 138, the annular flow path 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 liquid from the annular passage 133 (connection port 23 and flow path 63) to the main passage (main passage) and the introduction passage.

According to the second embodiment, it is possible to obtain the same effect as that of the first embodiment described above.

(Third Embodiment)
Next, the third embodiment will be described with reference to FIGS. 7 and 8. Here, the differences from the first embodiment will be described. For the parts common to the first embodiment, the same names and symbols will be used, and duplicate description will be 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-fit portion 112 of the screw 102 is slidably fitted into the shaft hole 114 of the ultra-fine low-speed valve 113 to slidably fit the non-press-fit portion 112 of the ultra-fine low-speed valve 113. The outer peripheral edge of the valve 113 is supported by the annular valve support 115 formed on the main body 41 (seat member), and the inner peripheral edge of the ultrafine low-speed valve 113 is supported by the seat surface 109 formed on the flange 130 of the screw 102. The valve mechanism 101 was configured so as to be able to take off and sit on the valve.

On the other hand, in the third embodiment, the valve mechanism 141 is provided on the inner circumference of the joint member 37 (the tubular portion of the passage member). The screw 142 is press-fitted into the opening on one end side of the tubular portion 38 of the joint member 37. The screw 142 is positioned in the axial direction with respect to the joint member 37 by bringing the flange portion 145 formed at the end portion on one end side into contact with the opening edge portion 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 peripheral edge of the shaft hole 146 opened on the other end surface of the screw 142 so that the disc-shaped ultrafine low-speed valve 143 can be detached and seated. A valve chamber 148 is formed inside the seat portion 147 with the ultra-fine low-speed valve 143 seated on the seat portion 147. The outer diameter of the ultrafine 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 end surface on the outer peripheral side of the ultrafine low-speed valve 143 and the tubular portion 38. The ultrafine low speed valve 143 is pressed against the seat portion 147 by a valve spring 150 provided in the tubular portion 38. The other end of the valve spring 150 is received by a spring receiving portion 151 formed at the opening edge of the shaft hole 55 that opens in the bottom surface 110 of the recess 50 of the main body 41.

The ultra-fine 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 microlow speed valve 143 is opened, the valve chamber 148 on the upstream side of the main body 41 passes through the gap 149 between the microlow speed valve 143 and the tubular portion 38, the flow path 63, and the recess 50 of the main valve 41. It communicates with the passage 51 (main passage) and also 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 liquid from the connection port 23 into the main passage (main passage) and the introduction passage.

According to the third embodiment, it is possible to obtain the same effect as that of the first embodiment described above.

1 Damping force adjustment type 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 adjustment mechanism , 32 Main valve, 33 Piston valve, 37 Joint member (passage member, cylinder part), 41 Main body (passage member, seating member), 45 Seat part (contact surface), 51 Passage (main flow path), 53 Introduction orifice (Introduction passage) 61 Piston chamber, 101 Valve mechanism

Claims (4)

With the outer cylinder
A cylinder provided inside the outer cylinder and filled with a working fluid,
A piston that is slidably fitted in the cylinder,
A piston rod with one end connected to the piston and the other end protruding outside the cylinder.
A separator tube provided on the outer circumference of the cylinder and
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 on the side wall of the separator tube and
A mounting hole provided in the outer cylinder so as to face the opening,
A damping force adjusting mechanism that is attached to the mounting hole and controls the flow of the working fluid between the annular oil passage and the reservoir to adjust the damping force generated.
Provided between the damping force adjusting mechanism and the opening, the inside becomes a flow path between the annular oil passage and the damping force adjusting mechanism, and the outside is between the damping force adjusting mechanism and the reservoir. A damping force-adjustable shock absorber provided with a passage member serving as a flow path.
The damping force adjusting mechanism is
A main valve that generates a damping force by introducing the flow of the working fluid accompanying the movement of the piston through the main flow path provided in the passage member.
A pilot chamber that applies internal pressure to the main valve in the valve closing direction,
An introduction passage for introducing the working fluid into the pilot chamber and
A pilot passage connecting the pilot chamber and the downstream side of the main valve,
A pilot valve provided in the pilot passage to discharge the working fluid of the pilot chamber is provided.
The passage member is provided with a valve mechanism that limits the inflow of working fluid into the main flow path and the introduction passage.
The passage member has a tubular portion fitted to the opening formed on one end side, and a contact surface provided on the other end side of the tubular portion and with which the damping force adjusting mechanism abuts.
The valve mechanism has a cylindrical screw having a flange portion at one end and a shaft portion at the other end, a screw passage formed in the screw, and a valve body for opening and closing the screw passage.
In a region where the piston speed is low, the valve body opens with the main valve closed, and in a speed region higher than the low speed, the main valve and the valve body open. Force-adjustable shock absorber. The damping force adjusting shock absorber according to claim 1, wherein the valve mechanism is provided on the inner circumference of the tubular portion. The passage member is provided with a seating member forming a seating surface of the main valve, a tubular portion fitted to the opening formed on one end side, and the seating member on the other end side of the tubular portion. The damping force adjusting type shock absorber according to claim 1 or 2, further comprising a joint member having a contact surface in contact with the contact surface. The damping force adjusting shock absorber according to claim 3, wherein the valve mechanism is provided between the joint member and the seating member.

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