JP7687595B2 - buffer - Google Patents

Description

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

Patent Document 1 discloses a damping force adjustment hydraulic shock absorber (hereinafter referred to as a "conventional shock absorber") with a side-mounted control valve that is equipped with a baffle plate that controls the flow of hydraulic fluid from an opening in the side wall of the outer cylinder through a damping force adjustment mechanism to a reservoir.

JP 2016-23661 A

In conventional shock absorbers, the axial length of the valve mechanism can be shortened and the damping force adjustment mechanism can be made smaller by connecting the damping force adjustment mechanism (main body) to the separator tube (middle tube) without providing a connecting member. In this case, the diameter of the opening formed in the outer tube becomes larger, which in turn increases the size of the baffle plate. When centering the cylinder relative to the outer tube during assembly of the rod guide, the partition wall of the baffle plate is pressurized (compressed) between the outer tube and the separator tube attached to the cylinder, but centering becomes difficult due to the increased elastic reaction force (assembly load) of the partition wall of the enlarged baffle plate, which reduces assembly ease.

The objective of the present invention is to provide a shock absorber that can prevent the deterioration of assembly ease that occurs when the baffle plate becomes larger.

The shock absorber of the present invention includes a cylinder in which a working fluid is sealed, a piston slidably inserted into the cylinder and dividing the interior of the cylinder into an upper chamber and a lower chamber, a piston rod having one end connected to the piston and the other end extending to the outside of the cylinder, an outer cylinder provided on the outer periphery of the cylinder, a reservoir formed between the cylinder and the outer cylinder, an intermediate cylinder provided on the outer periphery of the cylinder and having both ends fitted into the cylinder, an annular flow passage formed between the cylinder and the intermediate cylinder, a communication passage provided in a side wall of the cylinder and communicating between the upper chamber of the cylinder and the annular flow passage, a connecting pipe provided in a side wall of the intermediate cylinder, and an opening provided in a side wall of the outer cylinder at a position opposite to the connecting pipe. A shock absorber comprising an opening, a damping force adjustment mechanism connected to the connecting pipe, and a partition member provided in the reservoir and having a partition portion that controls the direction of flow of working fluid from the opening to the reservoir via the upper cylinder chamber, the communicating passage, the annular flow path, and the damping force adjustment mechanism, wherein the partition portion is located above the center of the connecting pipe and comprises an upper partition portion that extends in an arc shape when viewed from the front, and a pair of lower partition portions that extend downward from both ends of the upper partition portion, the upper partition portion having a groove formed on the inside, an upper end portion that protrudes outward, an outer surface that slopes from the upper end portion, and an R portion formed between the upper end portion and the outer surface, and the lower partition portion has a notch for adjusting the rigidity of the partition portion .

This invention makes it possible to prevent the deterioration of the assembly ease of the shock absorber caused by the increase in size of the baffle plate.

FIG. 2 is a cross-sectional view of the shock absorber according to the embodiment. FIG. 2 is an enlarged view of the damping force adjustment mechanism in FIG. FIG. 2 is a front view of the baffle plate according to the embodiment. This is a cross-sectional view taken along line AA in FIG. FIG. 4 is a bottom view of the baffle plate according to the embodiment. FIG. 5 is an enlarged view of part C in FIG. FIG. 13 is an explanatory diagram of a baffle plate showing another embodiment, in which a hollowed-out portion is provided on the inside of the upper part of the partition wall. FIG. 13 is an explanatory diagram of a baffle plate showing another embodiment, the figure showing an embodiment of a baffle plate in which a notch (lightening portion) is provided in the lower part of the partition wall.

An embodiment of the present invention will now be described with reference to the accompanying drawings.
As shown in Fig. 1, the shock absorber 1 according to this embodiment is a so-called control valve horizontally-mounted type hydraulic shock absorber with damping force adjustment, in which a damping force adjustment mechanism 30 is mounted horizontally on a side wall of an outer tube 3 (outer cylinder). The shock absorber 1 is disposed vertically on the vehicle. In the following description, the up-down direction in Fig. 1 will be referred to as the up-down direction of the shock absorber 1. For convenience, the left side in Fig. 2 (the side where the cylinder 2 is disposed) will be referred to as one side, and the right side in Fig. 2 (the side opposite to the side where the cylinder 2 is disposed) will be referred to as the other side.

The shock absorber 1 has a twin-cylinder structure with a cylinder 2 provided inside an outer tube 3. A reservoir 4 is formed between the outer tube 3 and the cylinder 2. A piston 5 is slidably inserted into the cylinder 2, dividing the interior of the cylinder 2 into an upper cylinder chamber 2A and a lower cylinder chamber 2B. The lower end of a piston rod 6 is connected to the piston 5. The upper end side of the piston rod 6 passes through the upper cylinder chamber 2A, and is inserted into a rod guide 8 and an oil seal 9 attached to the upper end of the cylinder 2 and the outer tube 3, and protrudes to the outside of the cylinder 2.

The piston 5 is provided with an extension passage 11 and a compression passage 12 that connect the cylinder upper chamber 2A and the cylinder lower chamber 2B. The compression passage 12 is provided with a disk valve 13 (check valve) that allows the flow of hydraulic fluid from the cylinder lower chamber 2B to the cylinder upper chamber 2A. On the other hand, the extension passage 11 is provided with a disk valve 14 (pressure adjustment valve) that opens when the pressure on the cylinder upper chamber 2A side reaches a set pressure and releases the pressure on the cylinder upper chamber 2A side to the cylinder lower chamber 2B side.

At the lower end of the cylinder 2, a base valve 10 is provided to separate the cylinder lower chamber 2B from the reservoir 4. The base valve 10 is provided with an extension side passage 15 and a compression side passage 16 that communicate between the cylinder lower chamber 2B and the reservoir 4. The extension side passage 15 is provided with a disk valve 17 (check valve) that allows the flow of hydraulic fluid from the reservoir 4 to the cylinder lower chamber 2B. On the other hand, the compression side passage 16 is provided with a disk valve 18 (pressure adjustment valve) that opens when the pressure on the cylinder lower chamber 2B side reaches a set pressure and releases the pressure on the cylinder lower chamber 2B side to the reservoir 4 side. The cylinder 2 is filled with hydraulic fluid, and the reservoir 4 is filled with hydraulic fluid and gas.

The outer periphery of the cylinder 2 is fitted with both ends of a separator tube 20 (middle cylinder) via a pair of upper and lower seal members 19, 19 so as to be able to slide. An annular flow passage 21 is formed between the cylinder 2 and the separator tube 20. The annular flow passage 21 is connected to the cylinder upper chamber 2A by a communication passage 22 provided in the side wall of the cylinder 2. A cylindrical connection pipe 23 that protrudes to the side and has an open tip is provided at the lower end side of the side wall of the separator tube 20. An opening 24 that faces the connection pipe 23 is provided in the side wall of the outer tube 3. A substantially cylindrical valve case 25 that is arranged coaxially with the opening 24 is provided in the side wall of the outer tube 3. The valve case 25 houses a damping force adjustment mechanism 30. The inner diameter of the valve case 25 and the hole diameter of the opening 24 are set to be the same.

As shown in FIG. 2, the damping force adjustment mechanism 30 has a back pressure type main valve 51 that generates a damping force. An annular packing 60 (elastic seal member) is joined to the outer peripheral edge of the back surface (other side surface) of the main valve 51. The damping force adjustment mechanism 30 further includes a main body 52 against which the main valve 51 abuts, a back pressure chamber 72 formed on the back of the main valve 51 and whose internal pressure acts on the main valve 51 in the valve closing direction, a pilot case 73 that forms the back pressure chamber 72, a pilot valve 71 that adjusts the internal pressure of the back pressure chamber 72 to control the opening pressure of the main valve 51, a pilot body 74 against which the pilot valve 71 abuts, a fail-safe valve 111 provided downstream of the pilot valve 71, and a solenoid 121 that controls the opening pressure of the pilot valve 71.

The outer peripheral edge of the other end face of the main body 52 is provided with an annular seat portion 53 against which the outer peripheral edge of the main valve 51 can be seated and released. An annular recess 55 is formed on the inner peripheral side of the seat portion 53 (upstream side of the main valve 51). A connection portion 65 is formed in the center of one end face of the main body 52, which is fitted (inserted) into the connecting pipe 23 of the separator tube 20. A seal ring 58 seals between the connection portion 65 of the main body 52 and the connecting pipe 23 to the separator tube 20.

A recess 66 with a regular hexagonal cross section that opens into the annular flow passage 21 is provided on one end face of the connection portion 65 of the main body 52. The main body 52 has a plurality of passages 67 (six in the second embodiment) that connect the recess 66 to the annular recess 55. A pin portion 85 that is inserted into the shaft hole 105 of the pilot case 73 is provided in the center of the other end face of the main body 52. A passage 93 that is arranged coaxially with the axis of the solenoid 121 opens on the other end face of the pin portion 85. The passage 93 is connected to the annular flow passage 21 via the recess 66 and an introduction orifice 94 provided in the main body 52.

Between the inner periphery 54 of the main body 52 and the inner periphery 76 of the pilot case 73, the main valve 51, the retainer and spacer (reference numbers omitted), and the back pressure introduction valve 81 are interposed. The tip (other side) of the pin portion 85 protrudes into the small inner diameter portion 91 provided at the bottom of the large inner diameter portion 90 that opens to the other end face of the pilot case 73. Then, by tightening the nut 87 screwed onto the threaded portion (reference numbers omitted) formed at the tip of the pin portion 85, an axial force is applied to the annular member interposed between the inner periphery 54 of the main body 52 and the inner periphery 76 of the pilot case 73, and the main body 52 and the pilot case 73 are integrated. When tightening the nut 87, a hexagonal wrench is engaged with the recess 66 (hexagonal hole).

An annular recess 77 is provided on the outer periphery of one end face of the pilot case 73. The annular recess 77 has an inner cylindrical surface 78 against which the packing 60 of the main valve 51 slidably abuts. An annular seat portion 79 is formed on the inner periphery of the annular recess 77. The outer periphery of the back pressure introduction valve 81 abuts against the seat portion 79 so that it can be seated and removed. An annular recess 80 is formed on the inner periphery of the seat portion 79. The annular recess 80 is connected to the space inside the small inner diameter portion 91 by a plurality of passages 92 (only "two" are shown in FIG. 2). In addition, a plurality of orifices (reference numbers omitted) that connect the back pressure chamber 72 to the annular flow passage 21 are provided on the outer periphery of the back pressure introduction valve 81.

The pilot body 74 is formed in a generally bottomed cylindrical shape with the other side open. One side of the pilot body 74 is fitted into the large inner diameter portion 90 of the pilot case 73. The pilot body 74 is positioned in the axial direction relative to the pilot case 73 by abutting against an annular surface 96 (step portion) formed between the large inner diameter portion 90 and the small inner diameter portion 91 of the pilot case 73. The gap between the pilot case 73 and the pilot body 74 is sealed by a seal ring 98.

Inside the pilot body 74, a valve chamber 100 is provided that houses the pilot valve 71 and the fail-safe valve 111. The working fluid is introduced into the valve chamber 100 from the annular flow passage 21 through the inlet orifice 94, the passage 93 formed in the pilot case 73, and the passage 101 formed in the center of the bottom of the pilot body 74. A seat portion 102 is provided on the peripheral edge of the other side opening of the passage 101 of the pilot body 74, against which the valve body 103 of the pilot valve 71 can be seated and released. The valve body 103 is formed in a substantially cylindrical shape, and one end portion is formed in a tapered shape. An outer flange-shaped spring receiving portion 104 is provided on the other side of the valve body 103. The valve body 103 is biased in the valve opening direction (to the other side) by a return spring 112 (nonlinear spring) that is an integrated pilot spring and fail-safe spring.

In the other side opening of the pilot body 74, a return spring 112, a spacer and a retainer (reference numbers omitted), and a washer 110 are stacked. These stacked parts are fixed to the pilot body 74 by a cap 115 attached to the outer periphery of the other side of the pilot body 74. The cap 115 is formed with a notch 116 (communication passage) that connects the valve chamber 100 to an annular passage 117 formed on the outer periphery of the cap 115. The valve chamber 100 is connected to the reservoir 4 via the notch 116 formed in the cap 115, the passage 117 formed on the outer periphery of the cap 115, the passage 118 formed between the two-face width 89 (only one surface is shown in FIG. 2) of the pilot case 73 and the cylindrical portion 123 of the yoke 122, and the annular passage 26 formed on the outer periphery of the main valve 51.

The pilot case 73 and the yoke 122 are fastened together by a fastening portion 124 formed by screwing a threaded portion (male thread) formed on the pilot case 73 into a threaded portion (female thread) formed on the cylindrical portion 123 of the yoke 122. This applies an axial force to the pilot body 74, return spring 112, spacer and retainer, washer 110, and cap 115 provided between the pilot case 73 and the yoke 122. When fastening the pilot case 73 and the yoke 122 together, a tool is engaged with the two-face width 89 formed on the pilot case 73 and the two-face width 138 formed on the yoke 122.

A coil 126, a core 127, a fixed core 128, a movable core 129, and a hollow operating rod 130 are attached to the other side of the yoke 122. The operating rod 130 is integral with the movable core 129, but may be configured separately. The valve body 103 of the pilot valve 71 is fixed to one end of the operating rod 130. A spacer 131 and a cover 132 are inserted into the other end of the yoke 122, and an axial force is applied to the solenoid internal parts in the yoke 122 by plastically processing (crimping) the other opening of the yoke 122.

The cylindrical portion 123 of the yoke 122 is fitted into the other opening of the valve case 25. The yoke 122 is positioned in the axial direction by abutting against the step portion 27 of the valve case 25. The gap between the yoke 122 and the valve case 25 is sealed by a seal ring 134. The yoke 122 is fixed to the valve case 25 by tightening a nut 135 screwed onto the valve case 25 and compressing a retaining ring 137.

When the coil 126 is not energized, the spring force of the return spring 112 biases the valve body 103 in the unseating direction (toward the other side). This causes the spring bearing portion 104 of the valve body 103 to abut (seat) on the fail-safe disk 113, and the fail-safe valve 111 is closed.

On the other hand, when the coil 126 is energized, the thrust of the movable iron core 129 urges the operating rod 130 in the seating direction (to one side) of the valve body 103. This causes the operating rod 130 to move against the spring force of the return spring 112, and the valve body 103 is seated on the seat portion 102. Here, the opening pressure of the valve body 103 is controlled by the value of the current passed through the coil 126. Note that in the soft mode, in which the value of the current passed through the coil 126 is small, the spring force of the return spring 112 and the thrust of the movable iron core 129 (operating rod 130) are balanced, and the valve body 103 is kept at a certain distance from the seat portion 102 (see FIG. 2).

Next, the baffle plate 31 (partition member) will be described.
2, the baffle plate 31 is provided in the reservoir 4 facing the opening 24. The baffle plate 31 controls the flow direction of the hydraulic fluid flowing from the flow path 26 of the damping force adjustment mechanism 30 through the opening 24 to the reservoir 4, and suppresses aeration caused by mixing the hydraulic fluid and gas in the reservoir 4.

The baffle plate 31 is attached to the outer periphery of the separator tube 20 (middle tube) and curved in an arc along the outer periphery 28 (curved surface) of the separator tube 20. As shown in Figures 3 to 5, the baffle plate 31 has a thin plate-shaped base 32 and a partition wall 37 provided on the edge of the base 32 except for the lower edge (lower side edge). The partition wall 37 protrudes from the edge of the base 32 to the other side (the "right side" in Figure 4), and its tip abuts against the inner periphery 7 of the outer tube 3.

When viewed from the front (see FIG. 3), the upper portion of the base 32 is formed in a substantially semicircular shape, and the lower portion is formed in a rectangular shape. Two seats 34, 34 (see FIG. 5) that come into contact with the reduced diameter portion 29 of the separator tube 20 are provided at a distance in the circumferential direction on the back surface 33 of the base 32. A connection port 35 that protrudes to the other side is provided in the center of the base 32. The connection port 35 is fitted to the outer periphery of the connection tube 23 of the separator tube 20 with a certain tightening margin. The baffle plate 31 of this embodiment is an integrally molded product made of a single material, and is made of a flexible elastic body such as NBR (nitrile rubber), but the material of the base 32 can be metal or plastic.

Here, the part of the partition wall 37 above the center of the connection port 35 (the part located above the connection pipe 23), i.e., the part above the line segment B-B in Figure 3 and shaped like a semicircular arch when viewed from the front, is referred to as the partition wall upper part 38.

As shown in FIG. 6, the partition upper portion 38 has a right-angled triangle in cross section taken along the axial plane of the connecting tube 23. The partition upper portion 38 has an inner surface 39 that is perpendicular to the base 32 and faces the opening 24 (see FIG. 2) of the outer tube 3, and an outer surface 40 (corresponding to the hypotenuse of the right-angled triangle) formed on the back surface of the inner surface 39. A groove 36 that is concave toward the back surface 33 of the base 32 (the "left side" in FIG. 6) is provided on the ridge between the inner surface 39 and the base 32. The groove 36 is provided over the entire length of the partition portion 37, and acts to cause the partition portion 37 to fall inward when the partition portion 37 is pressed between the outer tube 3 and the separator tube 20.

The dashed line 42 in FIG. 6 indicates the outer surface of a baffle plate in a conventional shock absorber, in other words, the outer surface of a baffle plate in a conventional shock absorber in which the opening diameter of the outer tube is smaller than the inner diameter of the valve case (hereinafter referred to as a "conventional baffle plate"). As shown in FIG. 6, the baffle plate 31 is hollowed out in the diagonal line portion between the dashed line 42 and the outer surface 40. For convenience, this diagonal line portion is referred to as the hollowed out portion 41. In this embodiment, the hollowed out portion 41 is provided on the outside of the upper partition wall portion 38.

The tip angle θ1 of the partition upper part 38 in the baffle plate 31, i.e., the angle θ1 between the inner surface 39 and the outer surface 40 of the partition upper part 38, is set to be smaller than 50 degrees, and is 40 degrees in this embodiment. In contrast, the tip angle θ2 of the partition upper part in a conventional baffle plate, i.e., the angle θ2 between the inner surface and the outer surface of the partition upper part, is generally 50 degrees or more, for example, 54 degrees. Note that the tip angle θ1 of the partition upper part 38 is not limited to 40 degrees, and by adjusting the tip angle θ1 within a range that does not impair the function of the baffle plate 31, the amount of removal of the partition upper part 38 by the removal part 41, and therefore the volume of the partition upper part 38, can be adjusted.

In this embodiment, the tip angle θ1 is used to adjust the volume of the partition upper part 38 to be equivalent to the volume of the partition upper part in a conventional baffle plate, thereby controlling the deformation (assembly load) of the partition upper part 38 when it is pressed between the outer tube 3 and the separator tube 20 during assembly. An R portion 43 (outer R) is formed at the tip of the partition upper part 38, i.e., the ridge between the inner surface 39 and the outer surface 40. In addition, the upper end part 44 of the base part 32 protrudes above (outside) the partition upper part 38. Furthermore, an R portion 45 (inner R) is formed between the partition upper part 38 and the upper end part 44 of the base part 32.

On the other hand, the partition portion 37 has partition lower portions 46, 46 that extend downward from both ends of the partition upper portion 38 along both end edges of the base portion 32 (both left and right side edges in FIG. 3). The partition lower portions 46, 46 have the same cross-sectional shape as the partition upper portion 38 (see FIG. 6), and thus smoothly connect to the partition upper portion 38. The tip angle of the partition lower portions 46, 46 is set to be the same as the tip angle θ1 of the partition upper portion 38. Furthermore, no protruding portion like the upper end portion 44 is formed on the outside of the partition lower portions 46, 46.

Next, the operation of the shock absorber 1 will be described.
The shock absorber 1 is disposed vertically between the sprung portion (vehicle body) and the unsprung portion (wheels) of a suspension device (not shown) of a vehicle. In a normal operating state, an on-vehicle controller (not shown) adjusts the opening pressure of the pilot valve 71 by controlling the current supplied to the coil 126 of the solenoid 121 of the damping force adjusting mechanism 30.

During the extension stroke of the piston rod 6, the disk valve 13 of the piston 5 closes due to the pressure rise in the cylinder upper chamber 2A, and the hydraulic fluid on the cylinder upper chamber 2A side is pressurized before the disk valve 14 opens. As a result, the hydraulic fluid is introduced into the damping force adjustment mechanism 30 through the communication passage 22, the annular flow passage 21, and the connection pipe 23. At this time, the hydraulic fluid moved by the piston 5 opens the disk valve 17 of the base valve 10 and flows from the reservoir 4 to the cylinder lower chamber 2B. When the pressure in the cylinder upper chamber 2A reaches the opening pressure of the disk valve 14 of the piston 5 and the disk valve 14 opens, the pressure in the cylinder upper chamber 2A is relieved to the cylinder lower chamber 2B, and an excessive pressure rise in the cylinder upper chamber 2A is avoided.

On the other hand, during the compression stroke of the piston rod 6, the pressure rises in the cylinder lower chamber 2B, opening the disc valve 13 of the piston 5, and closing the disc valve 17 of the passage 15 of the base valve 10. Before the disc valve 18 opens, hydraulic fluid flows from the piston lower chamber 2B to the cylinder upper chamber 2A. At this time, the hydraulic fluid of the volume that the piston rod 6 has entered into the cylinder 2 is introduced from the cylinder upper chamber 2A through the communication passage 22, the annular passage 21, and the connection pipe 23 to the damping force adjustment mechanism 30. When the pressure in the cylinder lower chamber 2B reaches the opening pressure of the disc valve 18 of the base valve 10 and the disc valve 18 opens, the pressure in the cylinder lower chamber 2B is relieved to the reservoir 4, and an excessive pressure rise in the cylinder lower chamber 2B is avoided.

The hydraulic fluid introduced into the damping force adjustment mechanism 30 is introduced into the annular recess 80 via the inlet orifice 94, a passage 93 provided in the main body 52, the small inner diameter portion 91 of the pilot case 73, and a passage 92 provided in the pilot case 73. When the pressure in the annular recess 80 reaches the opening pressure of the back pressure introduction valve 81, the back pressure introduction valve 81 opens, and the hydraulic fluid is introduced into the back pressure chamber 72.

Before the main valve 51 opens (low piston speed range), when the pressure upstream of the pilot valve 71 reaches the opening pressure of the valve body 103, the pilot valve 71 (valve body 103) opens, and the hydraulic fluid is introduced into the valve chamber 100 in the pilot body 74 through the introduction orifice 94, the passage 93, the small inner diameter portion 91, and the passage 101 provided in the pilot case 73.

The hydraulic fluid introduced into the valve chamber 100 flows through the notch 116 in the cap 115, the flow passage 117 on the outer periphery of the cap 115, the passage 118, and the flow passage 26 on the outer periphery of the main valve 51, and then flows from the opening 24 formed in the outer tube 3 to the reservoir 4. Then, when the piston speed increases and the pressure upstream of the main valve 51 (i.e., the pressure of the annular recess 55 connected to the annular flow passage 21 via the multiple passages 67) reaches the opening pressure of the main valve 51, the main valve 51 opens, and the hydraulic fluid in the annular flow passage 21 flows (is released) from the opening 24 of the outer tube 3 to the reservoir 4 through the recess 66, the multiple passages 67, the annular recess 55, the main valve 51, and the flow passage 26 on the outer periphery of the main valve 51.

In this way, during both the extension stroke and compression stroke of the piston rod 6, the damping force adjustment mechanism 30 generates a soft damping force according to the opening pressure of the inlet orifice 94 and the pilot valve 71 (valve body 103) before the main valve 51 opens (low piston speed range), and generates a hard damping force according to the opening degree of the main valve 51 after the main valve 51 opens (medium piston speed range).

Then, by controlling the current supply to the coil 126 to adjust the opening pressure of the pilot valve 71, it is possible to directly control the damping force regardless of the piston speed. In addition, by controlling the current supply to the coil 126 to adjust the opening pressure of the pilot valve 71, it is possible to open the back pressure introduction valve 81 and adjust the pressure of the hydraulic fluid introduced into the back pressure chamber 72, and the damping force characteristics can be adjusted over a wide range.

In addition, if the thrust of the movable core 129 (operating rod 130) is lost due to a failure such as a broken coil 126 or a malfunction of the on-board controller, the spring force of the return spring 112 causes the valve body 103 to move backwards to open the pilot valve 71, and the spring receiving portion 104 of the valve body 103 is brought into contact with the fail-safe disk 113, thereby blocking communication between the valve chamber 100 and the flow path 26 inside the valve case 25.

In this way, the fail-safe valve 111 controls the flow of hydraulic fluid from the annular passage 21 through the inlet orifice 94, the passage 93, the small inner diameter portion 91, the passage 101, the valve chamber 100, the notch 116, the passage 117, the passage 118, the passage 26, and the opening 24 to the reservoir 4. By varying the opening pressure of the fail-safe valve 111, it is possible to obtain a damping force according to the opening pressure, and at the same time, the internal pressure of the back pressure chamber 72 and therefore the opening pressure of the main valve 51 can be adjusted, so that a constant damping force can be obtained even when a failure occurs.

The working fluid flowing from the opening 24 to the reservoir 4 is sealed in the space inside the partition 37 of the baffle plate 31 (partition member), and is therefore isolated from the liquid surface of the working fluid in the reservoir 4. Furthermore, the baffle plate 31 prevents the working fluid flowing from the opening 24 to the reservoir 4 from moving upward and in the circumferential direction of the separator tube 20, and therefore prevents the jet of working fluid flowing from the opening 24 to the reservoir 4 from generating vortices or bubbles near the liquid surface of the working fluid in the reservoir 4.

In this way, the baffle plate 31 prevents the occurrence of aeration caused by the mixing of the gas and the hydraulic fluid, making it possible to obtain a stable damping force. In addition, the baffle plate 31 mitigates the sudden expansion of the flow path area of the hydraulic fluid flowing from the damping force adjustment mechanism 30 to the reservoir 4, thereby suppressing a sudden increase in the flow rate of the hydraulic fluid flowing to the reservoir 4 and preventing the occurrence of vortices. This also suppresses the occurrence of cavitation due to the generation of vortices, making it possible to obtain a stable damping force.

In conventional shock absorbers, the axial length of the valve mechanism can be shortened and the damping force adjustment mechanism can be made smaller by connecting the main body of the damping force adjustment mechanism to the separator tube (middle tube) without using a connecting member. In this case, the diameter of the opening formed in the outer tube is increased to avoid interference between the main body and the outer tube, which results in a larger baffle plate. When centering the cylinder relative to the outer tube during assembly of the rod guide, the partition wall of the baffle plate is pressurized (compressed) between the outer tube and the separator tube attached to the cylinder, but centering becomes difficult due to the increased elastic reaction force (assembly load) of the partition wall of the larger baffle plate, which reduces assembly ease.

In contrast, in the present embodiment, by providing hollowed-out portions 41 on the outside of the partition upper portion 38, which is located above the center of the connecting tube 23 of the separator tube 20 and which generates the majority of the elastic reaction force of the partition member 37, and in a pair of partition lower portions 46 extending downward from both ends of the partition upper portion 38, the volume of the partition upper portion 38 is set to be equivalent to the volume of the partition upper portion in a conventional baffle plate.
According to this embodiment, when the outer tube is centered relative to the cylinder 2 to which the separator tube 20 (intermediate tube) is attached during assembly of the rod guide 8, an increase in the elastic reaction force of the partition portion 37 of the baffle plate 31 is prevented, so that the assembly load (elastic reaction force) can be made equivalent to that of a conventional shock absorber, and the ease of assembly of the shock absorber 1 can be ensured without impairing the performance of the baffle plate 31.

The present embodiment is not limited to the above-described embodiment, and can be configured as follows, for example.
In the embodiment described above, the cutouts 41 are provided on the outside (outer surface 40) of the upper partition wall 38 and the lower partition wall 46, but as shown in Fig. 7, the baffle plate 31 may be configured so that the cutouts 41 are provided on the inside (inner surface 39) of the upper partition wall 38 and the lower partition wall 46, and the volumes of the upper partition wall 38 and the lower partition wall 46 are set to be equivalent to the volumes of the upper partition wall 38 and the lower partition wall 46 in a conventional baffle plate. Note that the dashed line 42 in Fig. 7 indicates the inner surface of the baffle plate in a conventional shock absorber.
Furthermore, the baffle plate 31 may be configured to provide the hollowed-out portions 41 on both the outer and inner sides of the partition upper portion 38 and the partition lower portion 46 to adjust the volume of the partition upper portion 38 .
In addition, in this embodiment, the cutouts 41 are provided in the upper partition wall 38 and the lower partition wall 46, but the baffle plate 31 may be configured by providing the cutouts 41 in either the upper partition wall 38 or the lower partition wall 46.
Either aspect can provide the above-mentioned advantageous effects.
8, the baffle plate 31 may be configured so as to provide notches 48 (lightweight portions) in the partition lower portion 46 to adjust the rigidity (elastic reaction force) of the entire partition portion 37. The number, shape, and position of the notches 48 may be set as appropriate.

1 Shock absorber, 2 Cylinder, 2A Cylinder upper chamber, 2B Cylinder lower chamber, 3 Outer tube (outer cylinder), 4 Reservoir, 5 Piston, 20 Separator tube (middle cylinder), 21 Annular flow passage, 22 Communication passage, 23 Connection pipe, 24 Opening, 30 Damping force adjustment mechanism, 31 Baffle plate (partition member), 38 Partition upper part, 41 Lightening part, 46 Partition lower part

Claims (2)

A cylinder in which a working fluid is sealed;
a piston that is slidably inserted into the cylinder and divides the inside of the cylinder into an upper cylinder chamber and a lower cylinder chamber;
a piston rod having one end connected to the piston and the other end extending to the outside of the cylinder;
An outer cylinder provided on the outer periphery of the cylinder;
a reservoir formed between the cylinder and the outer tube;
an intermediate cylinder provided on the outer periphery of the cylinder and having both ends fitted to the cylinder;
an annular flow passage formed between the cylinder and the intermediate tube;
a communication passage provided in a side wall of the cylinder, the communication passage connecting the upper cylinder chamber and the annular flow passage;
a connecting pipe provided on a side wall of the intermediate cylinder;
an opening provided in a side wall of the outer cylinder and opening at a position facing the connecting pipe;
a damping force adjustment mechanism connected to the connecting pipe;
a partition member provided within the reservoir, the partition member having a partition portion that controls a flow direction of hydraulic fluid that flows from the opening to the reservoir through the upper cylinder chamber, the communication passage, the annular flow passage, and the damping force adjustment mechanism;
A shock absorber comprising:
the partition wall portion is located above the center of the connecting pipe and includes an upper partition wall portion extending in an arc shape in a front view, and a pair of lower partition wall portions extending downward from both ends of the upper partition wall portion,
the partition upper portion has a groove formed on the inside, an upper end portion protruding outward, an outer side surface inclined from the upper end portion, and an R portion formed between the upper end portion and the outer side surface ,
A shock absorber , wherein a lower portion of the partition has a notch for adjusting the rigidity of the partition . 2. The shock absorber according to claim 1,
The shock absorber according to claim 1, wherein the groove is provided on an inner side of a lower portion of the partition wall.

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