Shock absorber and method for attaching damping force adjustment device

Abstract

Provided are: a shock absorber of which the degree of freedom in caulking a tubular body is enhanced; and a method for attaching a damping force adjustment device. A slit (weak section) is formed at an end section of a valve case (second tubular body) to reduce the stiffness of the end section of the valve case, and thus caulking is performed with a smaller caulking force, that is, the end section of the valve case can be bent with a smaller pressing force, thereby enhancing the degree of freedom in caulking the valve case (tubular body).

Description

Method for mounting shock absorber and damping force adjusting device

[0001] The present invention relates to a shock absorber equipped with a damping force adjusting device that controls the valve opening pressure of a valve body using an actuator, and a method for installing the damping force adjusting device.

[0002] Patent Document 1 discloses a damping force adjustable shock absorber 1 (hereinafter referred to as a "conventional shock absorber") in which a large diameter portion 50 having a tapered inner surface that gradually widens in diameter toward a solenoid case 42 is formed at one end of a thin wall portion 47 of a valve case 41.

[0003] JP 2019-027460 A

[0004] In conventional shock absorbers, when the valve case and solenoid case are integrated by crimping during the process of installing a damping force adjuster, a crimped portion is formed by using a jig that moves from the open end of the valve case toward the base end (left side in Figure 2) to pressurize one end of the thin wall portion of the valve case perpendicular to the direction of movement of the jig, bending it into the crimping groove of the solenoid case.

[0005] In the conventional method described above, a large crimping force is required to ensure sufficient connection strength (pull-out strength) between the valve case and the solenoid case, but this increases the load on the outer tube (external cylinder), which can cause deformation of the outer tube. As a result, it becomes necessary to increase the thickness of the outer tube, which increases the weight of the outer tube and, ultimately, the shock absorber.

[0006] An object of the present invention is to provide a method for mounting a shock absorber and a damping force adjusting device that improves the degree of freedom in caulking the cylindrical body.

[0007] The shock absorber of the present invention is a shock absorber used in a vehicle, the shock absorber having a damping force adjusting device, the damping force adjusting device having a tubular member that houses a damping force generating means and a solenoid that drives the damping force generating means, the tubular member having a first tubular body, a second tubular body that is arranged outside the first tubular body along the axial direction of the first tubular body, and a crimping portion that crimps and fixes the second tubular body to the first tubular body, the crimping portion comprising a groove portion that is arranged on at least a portion of the outer circumferential surface of the first tubular body in its circumferential direction, and an end portion of the second tubular body that is bent and accommodated within the groove portion, the end portion having a weak portion that is less rigid than other portions of the second tubular body. The method for mounting a damping force adjusting device of the present invention is a method for mounting a damping force adjusting device to a shock absorber used in a vehicle, and includes a pre-step of preparing a first cylindrical body having a groove on its outer peripheral surface and a second cylindrical body having a recess in which a portion of the outer peripheral surface is recessed relative to another portion; a second cylindrical body mounting step of mounting the second cylindrical body that houses a damping force generating means of the damping force adjusting device to the outer peripheral surface of the shock absorber; a damping force generating means accommodating step of accommodating the damping force generating means in the second cylindrical body; and a damping force adjusting step of accommodating the damping force generating means in the second cylindrical body after the damping force generating means accommodating step. The method is characterized by comprising: a first cylinder positioning step of assembling a solenoid for driving a generating means and positioning the first cylinder inside the second cylinder along the axial direction of the second cylinder; a clamping step of engaging a clamping member with the recess and clamping the second cylinder from the radial direction with the clamping member after the first cylinder positioning step; and a crimping step of crimping the second cylinder toward the first cylinder while moving a jig along the axial direction toward the open end of the second cylinder after the clamping step.

[0008] According to one embodiment of the present invention, in a method for attaching a shock absorber and a damping force adjusting device, the degree of freedom in caulking the cylindrical body can be improved.

[0009] FIG. 6 is a longitudinal sectional view of a shock absorber according to a first embodiment. FIG. 7 is an enlarged view of the damping force adjusting device in FIG. 1. FIG. 8 is an explanatory view of the first embodiment, illustrating the shape of the end of the valve case before crimping. FIG. 9 is an explanatory view of the first embodiment, showing a slit formed in the end of the valve case. FIG. 10 is an explanatory view of a method of installing the damping force adjusting device according to the first embodiment. FIG. 11 is an explanatory view of another embodiment of the first embodiment, showing a conceptual diagram of the valve case. FIG. 12 is a view taken in the direction of arrow A in FIG. 6. FIG. 13 is an explanatory view of a method of installing the damping force adjusting device according to a second embodiment. FIG. 14 is an explanatory view of another embodiment of the second embodiment.

[0010] (First embodiment) A first embodiment of the present invention will be described with reference to the accompanying drawings. A shock absorber 1 is mounted to a suspension device of a vehicle (not shown). The shock absorber 1 shown in Fig. 1 is a so-called control valve horizontally mounted damping force adjustable hydraulic shock absorber in which a damping force adjuster 31 is mounted horizontally on the side wall of an outer tube 3 (outer cylinder). For convenience, the up-down direction in Fig. 1 will be referred to as the "up-down direction."

[0011] The shock absorber 1 has a twin-cylinder structure in which a cylinder 2 is provided inside an outer tube 3, and a reservoir 4 is formed between the cylinder 2 and the outer tube 3. A piston 5 is slidably fitted within the cylinder 2, dividing the interior of the cylinder 2 into two chambers, an upper cylinder chamber 2A and a lower cylinder chamber 2B. The shock absorber 1 is equipped with a piston rod 6 whose lower end is connected to the piston 5 and whose upper end passes through the upper cylinder chamber 2A and protrudes to the outside of the cylinder 2. The piston rod 6 is inserted into a rod guide 7 fitted to the upper end of the cylinder 2. An oil seal 9 attached to a washer 8 seals the upper cylinder chamber 2A from the outside.

[0012] 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 extension passage 11 is provided with a disk valve 13 that opens to release pressure from the cylinder upper chamber 2A to the cylinder lower chamber 2B when the pressure in the cylinder upper chamber 2A reaches a set pressure. The compression passage 12 is provided with a check valve 14 that allows the flow of working fluid from the cylinder lower chamber 2B to the cylinder upper chamber 2A.

[0013] A base valve 10 is provided at the lower end of the cylinder 2, separating the cylinder lower chamber 2B from the reservoir 4. The base valve 10 is provided with an extension passage 15 and a compression passage 16 that communicate between the cylinder lower chamber 2B and the reservoir 4. The extension passage 15 is provided with a check valve 17 that allows the flow of working fluid from the reservoir 4 to the cylinder lower chamber 2B. The compression passage 16 is provided with a disc valve 18 that opens to release the pressure in the cylinder lower chamber 2B to the reservoir 4 when the pressure in the cylinder lower chamber 2B reaches a set pressure. Note that hydraulic fluid is sealed in the cylinder 2, and hydraulic fluid and gas are sealed in the reservoir 4 as the working fluid.

[0014] A separator tube 20 is attached to the outer periphery of the cylinder 2 via a pair of upper and lower seal members 19, 19. An annular oil passage 21 is formed between the cylinder 2 and the separator tube 20. A passage 22 is provided in the upper side wall of the cylinder 2, connecting the annular oil passage 21 to the cylinder upper chamber 2A. A cylindrical connection port 23 that protrudes to the right in FIG. 1 (outward in the cylinder radial direction) is provided in the lower side wall of the separator tube 20. A mounting hole 24 is provided in the side wall of the outer tube 3, coaxial with the connection port 23. A cylindrical valve case 121 (first cylinder) is provided in the side wall of the outer tube 3 to surround the mounting hole 24.

[0015] 2, the valve case 121 houses the damping force adjusting device 31. The damping force adjusting device 31 includes a valve block 33 (damping force generating means) integrated with valve components, and a solenoid block 101 (solenoid) integrated with solenoid components. The valve block 33 includes a back-pressure type main valve 41, a pilot valve 61 that controls the valve opening pressure of the main valve 41, and a fail-safe valve 91 provided downstream of the pilot valve 61.

[0016] A joint member 28 is inserted into the mounting hole 24 of the outer tube 3. The joint member 28 has a cylindrical tube portion 29, the left end of which in FIG. 2 is inserted into the connection port 23, and a flange portion 30 (outer flange) provided around the opening of the tube portion 29 on the right side in FIG. 2 and housed within the valve case 121. The tube portion 29 and the flange portion 30 are covered with a sealing material. The left end face (inner side in the cylinder radial direction) of the flange portion 30 in FIG. 2 abuts against the right end face (outer side in the cylinder radial direction) in FIG. 2 of an inner flange portion 122 of the valve case 121, and the right end face (in FIG. 2) abuts against the left annular end face (reference numeral omitted) of the main body 42 in FIG. 2. A flow path 35 on the outer periphery of the valve block 33 and the reservoir 4 are connected by a plurality of grooves 123 provided in the inner flange portion 122 of the valve case 121.

[0017] The valve block 33 includes an annular main body 42, an annular pilot body 62, and a pilot pin 63 that connects the main body 42 and the pilot body 62. An annular seat portion 43 is formed on the outer peripheral edge of the end face of the main body 42 on the right side in FIG. 2. The outer peripheral edge of the main disc 44 abuts against the seat portion 43 so as to be able to seat and separate from it.

[0018] The inner periphery of the main disc 44 is clamped between the inner periphery 45 of the main body 42 and the large diameter portion 64 of the pilot pin 63. An annular packing 46 is provided on the outer periphery of the main disc 44 on the right side in FIG. 2. An annular recess 47 is provided on the right end face of the main body 42 in FIG. 2. When the main disc 44 is seated on the seat portion 43, an annular passage 48 is formed between the main body 42 and the main disc 44. The annular passage 48 is connected to the flow path 35 on the outer periphery of the main body 42 via an orifice (reference numeral omitted) formed in the main disc 44. A recess 49 is formed in the center of the left end face of the main body 42 in FIG. 2. The recess 49 and the annular recess 47 (annular passage 48) are connected by multiple passages 50 (only two are shown in FIG. 2) formed in the main body 42.

[0019] The pilot pin 63 is formed in a cylindrical shape with a bottom that is open on the right side in Figure 2. An introduction orifice 65 is formed in the bottom of the left side of the pilot pin 63 in Figure 2. The left side of the pilot pin 63 in Figure 2 is press-fitted into the axial hole 51 of the main body 42. The right side of the pilot pin 63 in Figure 2 is press-fitted into the axial hole 66 of the pilot body 62. A plurality of grooves extending in the axial direction (the "left-right direction" in Figure 2) are formed in the outer peripheral surface of the right side of the pilot pin 63 in Figure 2, thereby forming a plurality of passages 67 (only one is shown in Figure 2) between the pilot body 62 and the pilot pin 63.

[0020] The pilot body 62 is formed in a generally cylindrical shape with a bottom that is open on the right side in FIG. 2. A flexible disk 69 is provided on the left side of the pilot body 62 in FIG. 2, and is clamped by the inner periphery of the pilot body 62 and the large diameter portion 64 of the pilot pin 63. A cylindrical portion 70 that is coaxial with the pilot body 62 is formed on the outer periphery of the left side of the pilot body 62 in FIG. 2. The packing 46 of the main valve 41 slidably abuts against the inner periphery of the cylindrical portion 70. As a result, a pilot chamber 71 is formed on the right side (back side) of the main disk 44 in FIG. 2. The pressure in the pilot chamber 71 acts on the main disk 44 in the valve closing direction (direction pressing against the seat portion 43).

[0021] A plurality of axially extending passages 72 (only two are shown in FIG. 2 ) are provided at the bottom of the pilot body 62 at equal intervals in the circumferential direction. A flexible disk 69 is seated on an annular seat portion 73 provided on the left end face of the pilot body 62 in FIG. 2 , thereby forming an annular passage (reference numeral omitted) inside (the inner periphery of) the seat portion 73. The left side of the passage 72 in FIG. 2 opens into the annular passage inside the seat portion 73. The flexible disk 69 bends when subjected to the internal pressure of the pilot chamber 71, thereby imparting volumetric elasticity to the pilot chamber 71.

[0022] The flexible disc 69 is formed by stacking multiple discs. A notch 75 that connects the passage 67 and the pilot chamber 71 is provided on the inner periphery of the disc that abuts against the large diameter portion 64 of the pilot pin 63. As a result, the oil in the annular oil passage 21 is introduced into the damping force adjuster 31 via the flow path 36 (axial hole) of the joint member 28, and then introduced into the pilot chamber 71 via the introduction passage, i.e., the introduction orifice 65, the axial hole 76 of the pilot pin 63, the passage 67, and the notch 75.

[0023] A recess 77 is formed on the right side of the pilot body 62 in FIG. 2. An annular seat portion 79 (valve seat) is provided at the bottom of the recess 77, against which the valve element 78 is removably seated. The seat portion 79 is provided on the periphery of the opening of the axial hole 66 of the pilot body 62, through which the working fluid passes. The valve element 78 is formed in a substantially cylindrical shape, and the end portion on the left side in FIG. 2 is tapered. An outer flange-shaped flange portion 80 is provided on the right side of the valve element 78 in FIG. 2. The valve element 78 is urged by the pilot spring 74 in a direction away from the seat portion 79 (to the right in FIG. 2).

[0024] A cylindrical portion 81 is formed on the right side of the pilot body 62 in Figure 2. The cylindrical portion 81 is provided with stacked components including the pilot spring 74, the failsafe disk 94, a retainer, a spacer, a washer, etc. These stacked components are fixed in place by a cap 98 fitted onto the outer periphery of the cylindrical portion 81. A passage 99 is formed between the cap 98 and the cylindrical portion 81 of the pilot body 62, connecting the recess 77 (valve chamber) with the flow path 35 on the outer periphery of the valve block 33.

[0025] The solenoid block 101 is formed by assembling a coil 103, cores 104 and 105, a plunger 106, and a hollow operating rod 107 connected to the plunger 106 into a solenoid case 102 (first cylindrical body). A spacer 108 and a cover 109 are inserted into the right side of the solenoid case 102 in FIG. 2. An axial force is applied to the components inside the solenoid case 102 by plastically processing the right edge of the solenoid case 102 in FIG. 2. When current is applied to the coil 103, the plunger 106 generates a thrust corresponding to the current value. The thrust generated by the plunger 106 acts to move the valve element 78 toward the seat portion 79 (leftward in FIG. 2) against the biasing force of the pilot spring 74.

[0026] The left end of the solenoid case 102 in FIG. 2 is inserted into the opening of the valve case 121 on the right side in FIG. 2. A seal member 110 seals the gap between the solenoid case 102 and the valve case 121. The left side of the actuation rod 107 in FIG. 2 protrudes into the recess 77 (valve chamber). A valve body 78 is attached to the left end of the actuation rod 107 in FIG. 2. In the first embodiment, the valve case 121 (second cylindrical body) is crimped toward the solenoid case 102 (first cylindrical body), thereby fixing the solenoid case 102 and the valve case 121 together, forming the cylindrical member 100 in which the solenoid case 102 and the valve case 121 are integrated, and also joining (integrating) the valve block 33 and the solenoid block 101. The crimped portion 118 (see FIG. 3) between the solenoid case 102 and the valve case 121 is covered with a cylindrical cover 111 (cover member).

[0027] When the coil 103 shown in FIG. 2 is not energized, the pilot spring 74 urges the valve element 78 in a direction away from the seat 79, causing the flange 80 of the valve element 78 to abut (seat) on the fail-safe disk 94. On the other hand, when the coil 103 is energized, a thrust force is generated on the plunger 106 in the leftward direction in FIG. 2, causing the operating rod 107 to move leftward in FIG. 2 against the urging force of the pilot spring 74, causing the valve element 78 to seat on the seat 79. The valve opening pressure of the valve element 78 is controlled by changing the value of the current energized through the coil 103. In the soft mode, when the current value energized through the coil 103 is small, the biasing force of the pilot spring 74 and the thrust of the plunger 106 are balanced, causing the pilot valve 61 to open by a constant valve opening amount (soft characteristic valve opening amount).

[0028] In the shock absorber 1, during the extension stroke of the piston rod 6, the pressure rises in the cylinder upper chamber 2A, causing the check valve 14 of the piston 5 to close, and before the disc valve 13 opens, the hydraulic fluid in the cylinder upper chamber 2A is pressurized. The pressurized hydraulic fluid passes through the passage 22 and the annular flow path 21, and is introduced into the damping force adjuster 31 from the connection port 23 of the separator tube 20 via the joint member 28. At this time, the hydraulic fluid equivalent to the amount of hydraulic fluid displaced by the piston 5 flows from the reservoir 4 into the cylinder lower chamber 2B, opening the check valve 17 of the base valve 10. When the pressure in the cylinder upper chamber 2A reaches the opening pressure of the disc valve 13 of the piston 5 and the disc valve 13 opens, the pressure in the cylinder upper chamber 2A is relieved to the cylinder lower chamber 2B. This prevents an excessive pressure rise in the cylinder upper chamber 2A.

[0029] On the other hand, during the compression stroke of the piston rod 6, the pressure rises in the cylinder lower chamber 2B, opening the check valve 14 of the piston 5 and closing the check valve 17 in the extension passage 15 of the base valve 10. Before the disc valve 18 opens, hydraulic fluid in the piston lower chamber 2B flows into the cylinder upper chamber 2A, and the volume of hydraulic fluid that has entered the cylinder 2 by the piston rod 6 is introduced from the cylinder upper chamber 2A through the passage 22, the annular passage 21, the connection port 23 of the separator tube 20, and the passage 36 of the joint member 28 to the damping force adjuster 31. When the pressure in the cylinder lower chamber 2B reaches the valve 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. This prevents an excessive pressure rise in the cylinder lower chamber 2B.

[0030] The hydraulic fluid introduced into the damping force adjuster 31 is introduced into the pilot chamber 71 via the inlet orifice 65 of the pilot pin 63, the axial hole 76, the recess 77 of the pilot body 62, the passage 72, and the flexible disc 69. Before the main valve 41 opens (when the piston speed is in the low-speed range), the hydraulic fluid that has flowed into the recess 77 passes through the pilot spring 74, the axial hole of the failsafe disc 94, the passage 99 between the cap 98 and the pilot body 62, the flow passage 35 on the outer periphery of the valve block 33, and the plurality of grooves 123 formed in the inner flange portion 122 of the valve case 121, and flows to the reservoir 4.

[0031] When the piston speed increases and the pressure of the working fluid introduced into the annular passage 48 via the annular oil passage 21, the flow path 36 of the joint member 28, and the passage 50 of the main body 42 reaches the opening pressure of the main valve 41 and the main valve 41 opens, the working fluid in the annular passage 48 flows to the reservoir 4 through the flow path 35 on the outer periphery of the valve block 33 and multiple grooves 123 formed in the inner flange portion 122 of the valve case 121.

[0032] In this way, during both the extension stroke and compression stroke of the piston rod 6, before the main valve 41 opens (when the piston speed is in the low-speed range), the damping force adjusting device 31 generates a damping force by passing the hydraulic fluid through the inlet orifice 65 and the pilot valve 61. After the main valve 41 opens (when the piston speed is in the medium-speed range), the damping force adjusting device 31 generates a damping force according to the opening degree of the main valve 41. Then, by controlling the energization of the coil 103 to adjust the valve opening pressure of the pilot valve 61, the damping force generated by the damping force adjusting device 31 can be directly controlled.

[0033] Furthermore, if the thrust of the plunger 106 is lost due to a failure such as a broken coil 103 or a malfunction of the on-board controller, the force of the pilot spring 74 (which also serves as a fail-safe spring) moves the valve body 78 in the direction opposite to the cylinder, opening the pilot valve 61, and causing the flange portion 80 of the valve body 78 to abut against the fail-safe disk 94, blocking communication between the inner flow path (reference number omitted) of the valve block 33 and the outer flow path 35.

[0034] This adjusts the valve opening pressure of the fail-safe valve 91, and controls the flow of hydraulic fluid from the annular oil passage 21 through the flow path 36 of the joint member 28, the inlet orifice 65 of the pilot pin 63, the axial hole 76, the recess 77 of the pilot body 62, the passage 99 between the cap 98 and the pilot body 62, the flow path 35 on the outer periphery of the valve block 33, and the plurality of grooves 123 formed in the inner flange portion 122 of the valve case 121 to the reservoir 4, thereby generating a constant damping force in the event of a failure. At the same time, it is possible to adjust the internal pressure of the pilot chamber 71, and therefore the valve opening pressure of the main valve 41, so that a constant damping force can be obtained even in the event of a failure.

[0035] 3 shows a state in which the solenoid case 102 (first cylindrical body) is arranged inside the valve case 121 (second cylindrical body) along the axial direction of the valve case 121 (arranged coaxially), and before the open end 125 on the right side (diametrically outer side of the cylinder) of the valve case 121 in FIG. 3 is crimped. The valve case 121 houses an internal component 32.

[0036] As shown in Figure 3, the end 125 of the valve case 121 is formed to have a smaller outer diameter than the other portions (the left portion in Figure 3, i.e., the portion radially inward of the cylinder). In other words, the end 125 of the valve case 121 is formed to be thinner than the other portions. An expanded diameter portion 126 is provided at the opening edge of the end 125 of the valve case 121, and the diameter expands so as to slope radially outward of the valve case 121 (the "upper side" in Figure 3) toward the open end of the valve case 121.

[0037] As shown in Figure 4, an end 125 of the valve case 121 is provided with a slit 127 (weak portion) that extends from the open end of the valve case 121 (expanded diameter portion 126) along the axial direction of the valve case 121 to the left in Figure 4 (diametrically inward in the cylinder direction) with a constant width W. The slit 127 reduces the rigidity of the end 125, and when the end 125 of the valve case 121 is crimped, it is possible to bend the end 125 of the valve case 121 radially inward of the valve case 121 ("downward" in Figure 3) with a smaller crimping force.

[0038] As shown in Figure 3, an annular crimping groove 112 (groove portion) that receives an end 125 of the valve case 121 bent by crimping is provided on the outer peripheral surface 117 of the solenoid case 102. The crimping groove 112 includes a bottom portion 113 having a constant outer diameter, a tapered portion 114 whose diameter increases from the right end of the bottom portion 113 in Figure 3 toward the right in Figure 3 (outward in the cylinder radial direction), a tapered portion 115 whose diameter increases from the left end of the bottom portion 113 in Figure 3 toward the left in Figure 3 (inward in the cylinder radial direction), and a flange surface 116 provided between the tapered portion 115 and the outer peripheral surface 117. Note that the crimping groove 112 does not need to be annular, i.e., formed around the entire circumference of the outer peripheral surface 117, and may be formed by providing a plurality of grooves intermittently.

[0039] Next, a method for installing the damping force adjuster 31 according to the first embodiment will be described with reference to Fig. 5. (Preliminary Process) First, the solenoid case 102 (first cylindrical body) and the valve case 121 (second cylindrical body) are prepared.

[0040] (Second Cylinder Attachment Process) Next, the valve case 121 is joined to the outer tube 3 (outer cylinder) by welding (fillet welding). As a result, a bead 128 having a substantially isosceles triangular cross section is formed along the edge between the valve case 121 and the outer tube 3. (Damping Force Generator Accommodation Process) Next, the valve block 33 (damping force generator) of the damping force adjuster 31 is assembled inside the valve case 121.

[0041] (First Cylinder Arrangement Process) After accommodating the valve block 33 in the valve case 121, the solenoid block 101 (excluding the coil 103, etc.) is assembled to the valve block 33. Next, the end of the solenoid case 102 on the inner side in the cylinder radial direction (the "upper side" in FIG. 5 ) is inserted into the inside of the end 125 of the valve case 121. As a result, the solenoid case 102 is arranged coaxially (along the axial direction) with respect to the valve case 121.

[0042] (Clamping Process) Next, as shown in Fig. 5 , the side wall of the outer tube 3 opposite to the side to which the valve case 121 is fixed is supported by a support member 130, and the cylindrical portion of the solenoid case 102 (the portion accommodating the coil 103) is supported by a guide member 131. In this state, the internal parts 32 (the valve block 33 and the solenoid block 101) inside the cylindrical member in which the solenoid case 102 and the valve case 121 are integrated are pressed toward the support member 130 in the cylinder radial direction (the "upward direction" in Fig. 5 ) by a pressing member 132, thereby applying an axial force to the internal parts 32. Furthermore, with the solenoid case 102 coaxially overlapping the valve case 121 by the amount of the crimping allowance, the outer peripheral surface 124 of the valve case 121 is clamped in the radial direction of the valve case 121 by a pair of clamping members 133, 133.

[0043] (Crimping process) Next, the end 125 of the valve case 121 is crimped with a crimping jig 135 to form a crimped portion 118 (see FIG. 3) at the overlapping portion of the solenoid case 102 and the valve case 121. Here, the jig 135 has a pair of rod-shaped link portions 137, 137 that are relatively rotatable about a hinge 136 (fulcrum), and pressure portions 138, 138 provided at one end of each link portion 137, 137 so as to face each other. The link portion 137 and the pressure portion 138 form an L-shape.

[0044] Then, in the crimping process, by applying pressure to the other ends (points of force) of the link portions 137, 137 of the crimping jig 135 in the closing direction, the tips (points of action) of the pressure applying portions 138, 138 of the crimping jig 135 bend (fall) the end 125 of the valve case 121 toward the crimping groove 112 (groove portion) of the solenoid case 102. At this time, pressure is applied to the end 125 of the valve case 121 while moving the crimping jig 135 at a constant speed in the axial direction of the solenoid case 102 and the valve case 121 (cylindrical member) and in a direction away from the outer tube 3 (the "downward direction" in FIG. 5 , the direction toward the open end of the second cylindrical body).

[0045] In Figure 5, for convenience, one of the pressure application portions 138, 138 of the crimping jig 135 (the pressure application portion 138 on the left side in Figure 5) is shown to be applying pressure to the portion of the end 125 of the valve case 121 where the slit 127 is formed, but in reality, both pressure application portions 138, 138 apply pressure to other portions of the end 125 of the valve case 121 (portions where the slit 127 is not formed).

[0046] Here, in the past, to ensure the connection strength (pull-out strength) between the valve case and the solenoid case, a large crimping force corresponding to that strength was required, which resulted in a large load being placed on the outer tube (external cylinder), causing the outer tube to deform.

[0047] In contrast, in the first embodiment, the rigidity of the end 125 of the valve case 121 (second cylindrical body) is reduced by forming a slit 127 (weak portion) in the end 125. This allows the end 125 of the valve case 121 to be crimped with a smaller crimping force, i.e., the end 125 of the valve case 121 can be bent with a smaller pressure, thereby improving the degree of freedom in crimping the cylindrical body (valve case 121). This reduces the load on the outer tube 3 and prevents deformation of the outer tube 3. Furthermore, because the rigidity of the end 125 of the valve case 121 is reduced by the slit 127, it is not necessary to increase the thickness of the outer tube 3 to withstand a large crimping force, so it is possible to prevent the outer tube 3 from becoming thicker and, therefore, the shock absorber 1 from becoming heavier. In the first embodiment, before crimping, the opening edge of the end 125 of the valve case 125 is provided with the expanded diameter portion 12 that slopes radially outward of the valve case 121 toward the open end of the valve case 121, so that in the first cylindrical body arrangement step described above, it is possible to easily center the solenoid case 102 (first cylindrical body) with respect to the valve case 121 (second cylindrical body). Also, by providing the expanded diameter portion 126 at the end 125 of the valve case 121, it is possible to prevent damage to the seal member 110 (O-ring) attached to the solenoid case 121 when inserting the solenoid case 102 into the valve case 121, thereby suppressing the occurrence of contamination and improving the reliability of the shock absorber 1. In the first embodiment, in the above-mentioned crimping process, the crimping jig 135 is moved at a constant speed in the axial direction of the solenoid case 102 and the valve case 121 (cylindrical member) and away from the outer tube 3, while applying pressure to the end 125 of the valve case 121. This makes it possible to release the crimping force acting on the outer tube 3 (a force acting to deform the cross-sectional shape of the outer tube 3), and more reliably prevents deformation of the outer tube 3.In the first embodiment, the slit 127 (weak portion) extends from the opening end of the valve case 121 in the axial direction of the valve case 121 toward the outer tube 3. Therefore, for example, when the shock absorber 1 is attached to a vehicle, by positioning at least one of the slits 127 (only one in the first embodiment) in a semi-circumferential region on the side closer to the road surface of the end 125 of the valve case 121, water that has penetrated inside the cover 111 (cover member) can be discharged to the outside of the cover 111 through the slit 127, thereby improving the water drainage ability within the cover 111.

[0048] The first embodiment is not limited to the above-described configuration, and can be configured, for example, as follows: In the first embodiment, the end 125 of the valve case 121 is provided with a slit 127 (weak portion) extending with a constant width W from the open end of the valve case 121 along the axial direction of the valve case 121, thereby reducing the rigidity (bending strength) of the end 125 of the valve case 121. However, instead of providing the slit 127, as shown in Figures 6 and 7 , a plurality of recesses 129 (weak portions) extending axially (to the left in Figure 6 ) from the open end of the end 125 may be provided on the outer circumferential surface of the end 125 of the valve case 121 at equal intervals around the circumferential direction of the valve case 121.

[0049] Second Embodiment Next, a second embodiment will be described with reference to Fig. 8. Here, differences from the first embodiment will be described. Note that the same names and symbols will be used for parts common to the first embodiment, and duplicate descriptions will be omitted.

[0050] In the first embodiment, in the clamping step of the method for attaching the damping force adjuster 31, the outer peripheral surface 124 of the valve case 121 (first cylindrical body) is clamped in the radial direction of the valve case 121 by a pair of clamping members 133, 133 to guide the valve case 121 in the axial direction. Also, in the first embodiment, the pressing force (axial force of the internal machine part 32) by the pressing member 132 and the axial component of the crimping force acting on the valve case 121 (force acting to press the valve case 121 against the outer tube 3 (outer tube)) are received by the support member 130 abutting against the side wall of the outer tube 3 on the side opposite to the side to which the valve case 121 is fixed.

[0051] In contrast to this, in the second embodiment, a two-sided width portion 141 (a recessed portion recessed relative to other portions of the outer peripheral surface 124) having a constant width in the axial direction (a width corresponding to the plate thickness of the clamping member 133) is provided on the outer peripheral surface 124 of the valve case 121, and during the clamping process, a pair of clamping members 133, 133 are engaged (hooked) with the two-sided width portion 141.

[0052] According to the second embodiment, the force that was received by the outer tube 3 (support member 130) in the first embodiment, i.e., the pressing force by the pressing member 132 and the axial component of the crimping force acting on the valve case 121, can be received by the pair of clamping members 133, 133, thereby reliably preventing deformation of the outer tube 3 during the crimping process. Furthermore, in the second embodiment, it is possible to omit the support member 130 from the manufacturing equipment of the first embodiment, thereby simplifying the equipment.

[0053] The second embodiment is not limited to the above-described configuration, and may be configured, for example, as follows: In the second embodiment, a two-flat portion 141 is provided on the outer peripheral surface 124 of the valve case 121 to form a recess that is recessed relative to the other portions of the outer peripheral surface 124. However, for example, an annular groove (141) may be provided on the outer peripheral surface 124 of the valve case 121 to form the recess. Also, as shown in Fig. 9 , a recess 143 (a portion recessed relative to the other portions) having a height (axial length) H from the outer tube 3 and extending circumferentially along the ridge between the outer tube 3 and the valve case 121 may be provided on the end of the valve case 121 on the outer tube 3 side (the "upper side" in Fig. 9 ). The ridge between the recess 143 and the outer tube 3 may be welded to form a bead 128, and a pair of clamping members 133, 133 may be engaged (hooked) on the side of the recess 143 opposite the outer tube 3 side (the "lower side" in Fig. 9 ). In this case, the weld bead 128 is housed inside the recess 143, thereby improving the design of the shock absorber 1. Furthermore, because the outer diameter of the bead 128 can be reduced, it is possible to reduce the size of the hole formed in the bracket (not shown) for passing the damping force adjuster 31 through, thereby improving the rigidity of the bracket and, ultimately, the mounting strength of the shock absorber 1.

[0054] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0055] This application claims priority based on Japanese Patent Application No. 2022-167233, filed October 18, 2022. The entire disclosure of Japanese Patent Application No. 2022-167233, filed October 18, 2022, including the specification, claims, drawings, and abstract, is incorporated herein by reference in its entirety.

[0056] 1 shock absorber, 31 damping force adjusting device, 101 solenoid block (solenoid), 102 solenoid case (first cylindrical body), 112 crimping groove (groove portion), 117 outer peripheral surface (outer peripheral surface of first cylindrical body), 118 crimping portion, 121 valve case (second cylindrical body), 125 end (end portion of first cylindrical body)

Claims

1. A shock absorber for use in a vehicle, comprising: The shock absorber has a damping force adjusting device, The damping force adjusting device is a cylindrical member that accommodates therein a damping force generating means and a solenoid that drives the damping force generating means; The cylindrical member is A first cylinder; a second cylindrical body provided outside the first cylindrical body and along an axial direction of the first cylindrical body; a crimping portion that crimps and fixes the second cylindrical body to the first cylindrical body, The crimping portion is A groove portion is provided on at least a part of the outer circumferential surface of the first cylindrical body in the circumferential direction; an end portion of the second cylindrical body that is bent and accommodated in the groove; It consists of: the end portion has a weak portion having a lower rigidity than the other portion of the second cylindrical body, The fragile portion is a plurality of recesses extending in the axial direction from an open end of the end portion on an outer peripheral surface of the end portion of the second cylindrical body. A shock absorber characterized by:

2. A shock absorber for use in a vehicle, comprising: The shock absorber has a damping force adjusting device, The damping force adjusting device is a cylindrical member that accommodates therein a damping force generating means and a solenoid that drives the damping force generating means; The cylindrical member is A first cylinder; a second cylindrical body provided outside the first cylindrical body and along an axial direction of the first cylindrical body; a crimping portion that crimps and fixes the second cylindrical body to the first cylindrical body, The crimping portion is A groove portion is provided on at least a part of the outer circumferential surface of the first cylindrical body in the circumferential direction; an end portion of the second cylindrical body that is bent and accommodated in the groove; It consists of: the end portion has a weak portion having a lower rigidity than the other portion of the second cylindrical body, The fragile portion is at least one slit formed in the end portion and extending in the axial direction of the tubular member. A shock absorber characterized by:

3. 3. The shock absorber according to claim 2, The end portion is expanded in diameter so as to be inclined radially outward of the cylindrical member before being crimped. A shock absorber characterized by:

4. The shock absorber according to claim 2 or 3, The damping force adjusting device is A cover member for covering an outer circumferential side of the crimping portion is further provided. The at least one slit is provided at an arbitrary location of a half circumference located on a side closer to a road surface of the end portion when the shock absorber is attached to the vehicle. A shock absorber characterized by:

5. A shock absorber for use in a vehicle, comprising: The shock absorber has a damping force adjusting device actuated by a solenoid, The damping force adjusting device is a cylindrical member that accommodates therein a damping force generating means and the solenoid that drives the damping force generating means; The cylindrical member is A first cylinder; a second cylindrical body provided on the outside of the first cylindrical body along the axial direction of the first cylindrical body, the second cylindrical body having a recess in which a part of an outer circumferential surface is recessed relative to another part, and the first cylindrical body is fixed to the second cylindrical body; A shock absorber characterized by:

6. 6. The shock absorber according to claim 5, The damping force adjusting device is attached to an outer cylinder of the shock absorber by welding, The recess is provided at a position facing the outer cylinder, The recessed portion accommodates the weld bead. A shock absorber characterized by:

7. A method for attaching a damping force adjusting device to a shock absorber used in a vehicle, comprising the steps of: a front-end process of preparing a first cylindrical body having a groove on an outer peripheral surface thereof and a second cylindrical body having a plurality of recesses on an outer peripheral surface of an end portion of the second cylindrical body, the recesses extending in an axial direction from an open end of the end portion; a second cylinder attachment step of attaching the second cylinder, which houses a damping force generating means of the damping force adjusting device, to an outer peripheral surface of the shock absorber; a damping force generating means accommodating step of accommodating the damping force generating means in the second cylindrical body; a first cylinder arrangement step of assembling a solenoid for driving the damping force generating means and arranging the first cylinder inside the second cylinder along an axial direction of the second cylinder after the damping force generating means accommodation step; a clamping step of engaging a clamping member with the recess and clamping the second cylindrical body from a radial direction by the clamping member, which is performed after the first cylindrical body placement step; and a crimping step of crimping the second cylindrical body toward the first cylindrical body while moving a jig toward an open end of the second cylindrical body along the axial direction after the clamping step. A method for mounting a damping force adjusting device, comprising: