Nut member, buffer device and compression tool

Abstract

To provide a nut member and so on which can seal a spiral passage formed by a male thread and a female thread without applying an adhesive.SOLUTION: A nut member is formed with a female thread with which a male thread is tightened. A tightening part between the male thread and the female thread is connected to a liquid-tight chamber being a portion in which liquid is enclosed. The nut member has a plastic flow part formed by plastic flow in at least a part of a circumference of the female thread.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a nut member, a shock absorber, and a pressure tool. [Background technology]

[0002] For example, the pressure buffer device described in Patent Document 1 includes a rod inserted into a cylinder that contains liquid and movable axially relative to the cylinder, and a piston connected to the rod that divides the space within the cylinder into a first liquid chamber and a second liquid chamber that contain liquid. The pressure buffer device described in Patent Document 1 also includes a flow path forming portion that forms a flow path for liquid between the first liquid chamber and the second liquid chamber, a valve portion that opens and closes the flow path in the flow path forming portion to generate a damping force, and a damping force changing portion that has an inflow portion into which liquid flows and changes the damping force generated by the valve portion depending on the pressure of the liquid in the inflow portion. The damping force changing portion also includes a pressure changing portion that changes the pressure of the liquid in the inflow portion by deforming or displacing, a support portion that supports the pressure changing portion, and an inflow forming portion that holds the support portion with a crimped portion and forms the inflow portion together with the support portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6539009 Summary of the Invention [Problem to be solved by the invention]

[0004] In the pressure damping device described in Patent Document 1, in order to change the damping force generated in the valve unit, oil that flows from the second oil chamber into the bypass passage during the extension stroke passes through an orifice in the throttle member and a communication passage in the piston nut before flowing into the pressure adjustment chamber. Therefore, it is desirable to prevent oil that flows into the bypass passage from the second oil chamber from flowing into the pressure adjustment chamber via a spiral passage formed between the male thread formed in the mounting portion on one end of the rod and the female thread formed in the piston nut. While applying adhesive to seal the spiral passage is considered, applying adhesive requires a long time for the adhesive to dry, lengthening the assembly time. An object of the present invention is to provide a nut member or the like that can seal a spiral passage formed by a male thread and a female thread without applying an adhesive. [Means for solving the problem]

[0005] The present invention, which was completed with this objective in mind, is a nut member having a female thread formed thereon onto which a male thread is tightened, in which the tightening portion between the male thread and the female thread is connected to a liquid-tight chamber in which the liquid is sealed, and in which at least a portion of the periphery of the female thread has a plastic flow portion formed by plastic flow. [Effects of the Invention]

[0006] According to the present invention, the spiral passage formed by the male and female threads can be sealed without applying an adhesive. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a suspension device according to a first embodiment. [Figure 2] 3 is a diagram showing an example of a cross section of a piston portion and a damping force change portion according to the first embodiment. FIG. [Figure 3] FIG. 2 is a diagram illustrating an example of a schematic configuration of a diaphragm member. [Figure 4] FIG. 2 is a diagram illustrating an example of a schematic configuration of a support spring. [Figure 5] FIG. 2 is a perspective view showing an example of an end cap, a float valve, and a pressure adjustment chamber spring. [Figure 6] 4 is a diagram showing an example of a partial cross section of a damping force changing portion; FIG. [Figure 7] 5A to 5C are explanatory diagrams illustrating the operation of the piston portion and the bottom portion during the compression stroke and the extension stroke. [Figure 8] 10A and 10B are diagrams illustrating an example of the operation of the damping force change unit during an extension stroke. [Figure 9] 10A and 10B are diagrams illustrating an example of how the damping force changing unit is assembled. [Figure 10] 9A and 9B are diagrams showing an example of the state of a piston nut before and after it is pressurized with a pressure tool, where (a) is a diagram showing an example of the state before the piston nut is pressurized, and (b) is a diagram showing an example of the state after the piston nut is pressurized. [Figure 11] FIG. 1 is a diagram illustrating an example of a pressure tool. [Figure 12] 10A and 10B are diagrams showing examples of modified cross-sectional shapes of protrusions. [Figure 13] 10A and 10B are diagrams showing examples of modified circumferential shapes of protrusions. [Figure 14] FIG. 10 is a diagram showing an example of a pressure tool according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First Embodiment FIG. 1 is a diagram showing an example of a schematic configuration of a suspension system 1 according to the first embodiment. The suspension system 1 is a suspension used in four-wheeled vehicles such as passenger cars, and as shown in Fig. 1, comprises a hydraulic shock absorber 2 and a coil spring 3 arranged on the outside of the shock absorber 2. The suspension system 1 also comprises a lower spring seat 4 that supports an end of the coil spring 3 on a first axial side (lower side in Fig. 1) of a rod 20 described below, and an upper spring seat 5 that supports an end of the coil spring 3 on a second axial side (upper side in Fig. 1) of the rod 20.

[0009] The suspension device 1 also includes a vehicle body side bracket 6 for attaching the suspension device 1 to a vehicle, a wheel side bracket 7 for attaching the suspension device 1 to a wheel, and a dust cover 8 that covers at least a portion of the cylinder portion 10 and the rod 20. Hereinafter, the axial direction of the rod 20 may be simply referred to as the "axial direction." Furthermore, the first axial side (lower side in FIG. 1) and the second axial side (upper side in FIG. 1) may be simply referred to as the "first side" and the "second side," respectively. Furthermore, the direction intersecting the axial direction (for example, the perpendicular direction) may be simply referred to as the "radial direction." In the radial direction, the side of the center line of the cylinder 11 may be simply referred to as the "inner side," and the side away from the center line may be simply referred to as the "outer side."

[0010] The shock absorber 2 will be described in detail below. The shock absorber 2 includes a cylinder portion 10 that stores oil, and a rod 20 whose second end protrudes from the cylinder portion 10 and whose first end is inserted into the cylinder portion 10. The shock absorber 2 also includes a piston portion 30 that is provided at the first end of the rod 20, a damping force changing portion 40 that adjusts the damping force generated by the piston portion 30, and a bottom portion 60 that is provided at the first end of the cylinder portion 10.

[0011] [Cylinder part 10] The cylinder section 10 includes a thin-walled cylindrical cylinder 11, a thin-walled cylindrical outer cylinder 12 provided on the outside of the cylinder 11, and a bottom cover 13 that closes a first end of the outer cylinder 12. The cylinder 11 and the outer cylinder 12 are arranged so that the center line direction of the cylinder coincides with the axial direction. The cylinder section 10 forms a reservoir chamber R between the outer peripheral surface of the cylinder 11 and the inner peripheral surface of the outer cylinder 12. The reservoir chamber R is filled with oil on the first side and gas on the second side.

[0012] The cylinder portion 10 also includes a rod guide 14 that movably supports the rod 20, a bump stopper cap 15 attached to the second end of the outer tube 12, and a sealing member 16 that prevents oil from leaking from within the cylinder portion 10 and prevents foreign matter from entering the cylinder portion 10.

[0013] [Rod 20] The rod 20 is a solid or hollow rod-shaped member. The rod 20 has a first-side mounting portion 21 provided on a first side, a second-side mounting portion 22 provided on a second side, and a shaft portion 23 between the first-side mounting portion 21 and the second-side mounting portion 22. The first-side mounting portion 21 and the second-side mounting portion 22 each have a spiral groove cut into their outer surface and function as a bolt. A male thread 213 (see FIG. 2) is formed at the first-side end of the first-side mounting portion 21, and the first-side mounting portion 21 holds the piston portion 30 and an adjustment valve 41 and a piston nut 43 (described later) of the damping force changer 40. The second-side mounting portion 22 holds a vehicle-side bracket 6, and the vehicle-side bracket 6 is connected to, for example, the vehicle body.

[0014] 2, the rod 20 is provided with a bypass passage 25 that allows oil to circulate between the second chamber Y2 and the first chamber Y1, bypassing the extension-side oil passage 341 of the piston portion 30. The bypass passage 25 is composed of a groove extending in the radial direction formed at the first-side end of the shaft portion 23, and a groove extending in the axial direction formed on the second side of the spiral groove in the first-side mounting portion 21 (in other words, the male thread 213 (see FIG. 2)).

[0015] [Bottom part 60] As shown in FIG. 1, the bottom portion 60 includes a valve body 61 having a plurality of oil passages passing through in the axial direction, a valve 62 provided on a first side of the valve body 61, and a valve 63 provided on a second side of the valve body 61. The valve body 61 of the bottom portion 60 separates the first chamber Y1 and the reservoir chamber R.

[0016] [Piston part 30] FIG. 2 is a diagram showing an example of a cross section of the piston portion 30 and the damping force change portion 40 according to the first embodiment. FIG. 3 is a diagram showing an example of a schematic configuration of the diaphragm member 42. As shown in FIG. FIG. 4 is a diagram showing an example of a schematic configuration of the support spring 46. As shown in FIG. FIG. 5 is a perspective view showing an example of the end cap 51, the float valve 52, and the pressure adjustment chamber spring 53. FIG. 6 is a diagram showing an example of a partial cross section of the damping force changing section 40. As shown in FIG.

[0017] 2, the piston portion 30 includes a piston 31, an extension side damping valve portion 321 provided on a first side of a cylindrical portion 311 (described later) of the piston 31, and a compression side damping valve portion 322 provided on a second side of the piston 31. The piston portion 30 also includes a first valve stopper 351 and a second valve stopper 353.

[0018] Piston 31 has a columnar portion 311 formed in a substantially cylindrical shape and having a plurality of oil passages, which will be described later, formed therein, and a cylindrical portion 312 provided on a first side of columnar portion 311. The piston 31 contacts the cylinder 11 via a sliding portion provided on the radially outer side to reduce frictional resistance. The piston portion 30 divides the space in the cylinder 11 filled with oil into a first chamber Y1 on the first side and a second chamber Y2 on the second side.

[0019] Furthermore, the piston 31 has a mounting hole 33R through which the rod 20 passes, and an extension-side oil passage 341 and a compression-side oil passage 342 formed radially outward from the mounting hole 33R. A plurality of extension-side oil passages 341 and a plurality of compression-side oil passages 342 are provided at approximately equal intervals in the circumferential direction. The extension-side oil passage 341 and the compression-side oil passage 342 each enable oil to flow between the first chamber Y1 and the second chamber Y2.

[0020] The extension side damping valve portion 321 can be configured by a plurality of elastic, substantially disk-shaped plates. The extension side damping valve portion 321 always opens the first side of the compression side oil passage 342, and opens and closes the first side of the extension side oil passage 341. The compression side damping valve portion 322 can be configured by a plurality of elastic, substantially disk-shaped plates. The compression side damping valve portion 322 always opens the second side of the extension side oil passage 341, and opens and closes the second side of the compression side oil passage 342.

[0021] The first valve stopper 351 has a mounting hole 351R through which the rod 20 passes. The second valve stopper 353 has a first outer diameter portion 353a having a predetermined outer diameter and a second outer diameter portion 353b having an outer diameter larger than that of the first outer diameter portion 353a. The second valve stopper 353 is provided so that the first outer diameter portion 353a fits inside the cylindrical portion 312 of the piston 31. When the extension side damping valve portion 321 deforms, the second valve stopper 353 prevents the extension side damping valve portion 321 from deforming more than a certain amount. The second valve stopper 353 also functions as a valve seat for the adjustment valve 41, which will be described later.

[0022] The second valve stopper 353 also has an attachment hole 353R that extends in the axial direction and has an inner diameter that allows the first-side attachment portion 21 of the rod 20 to pass through. The second valve stopper 353 also has a recess 353c that opens toward the adjustment valve 41, which will be described later. The first side mounting portion 21 of the second valve stopper 353 is fitted into the mounting hole 353R, and the extension side damping valve portion 321 is sandwiched between the first side mounting portion 21 and the piston 31. The recess 353c of the second valve stopper 353 is a space that communicates with the bypass passage 25.

[0023] [Damping force changing unit 40] 2, the damping force change unit 40 has an adjustment valve 41 that controls the flow of oil in the bypass path 25, a throttle member 42 that throttles the flow of oil in the bypass path 25, and a piston nut 43 that connects to the rod 20. Furthermore, the damping force change unit 40 has a spool 44 that is provided movably with respect to the piston nut 43, an O-ring 45 that seals the gap between the piston nut 43 and the spool 44, and a support spring 46 that applies a spring force to the spool 44. Furthermore, the damping force changer 40 has an end cap 51 that forms a pressure adjustment chamber 500 together with the piston nut 43 , a float valve 52 that changes the oil pressure in the pressure adjustment chamber 500 , and a pressure adjustment chamber spring 53 .

[0024] The adjusting valve 41 covers the recessed portion 353c of the second valve stopper 353. When the adjusting valve 41 is deformed and no longer covers the recessed portion 353c, the adjusting valve 41 opens the recessed portion 353c and allows oil in the second chamber Y2 to flow to the first chamber Y1 side through the bypass path 25 and the recessed portion 353c.

[0025] As shown in Fig. 3, the throttle member 42 is elastic and has an annular shape. The throttle member 42 has an opening 42H on the radially inner side, through which the first-side mounting portion 21 of the rod 20 passes, and an orifice 42S cut outward from the opening 42H. The throttle member 42, together with the adjustment valve 41, is provided between the second valve stopper 353 and the piston nut 43. As shown in Fig. 6, the orifice 42S extends to a pressure chamber 47 (described later). The orifice 42S is connected to the first end of the bypass path 25. In this embodiment, two orifices 42S are provided in the circumferential direction, but the number, length, slit width, etc. can be set as appropriate.

[0026] (Piston nut 43) The piston nut 43 has a columnar portion 431, an annular protruding portion 432 provided on the second side of the columnar portion 431, and a cylindrical portion 433 provided on the first side. The columnar portion 431 has an internal thread 43R that extends in the axial direction and is fastened to an external thread 213 formed in the first-side mounting portion 21 of the rod 20, and a communication passage 43H that is formed on the outside of the internal thread 43R and penetrates in the axial direction from the annular protrusion 432 side to the cylindrical portion 433. In this embodiment, a plurality of communication passages 43H are provided in the circumferential direction of the piston nut 43.

[0027] 6, the cylindrical portion 433 has a nut tapered portion 433T on the inside. The nut tapered portion 433T is inclined toward the first side with respect to the axial direction. That is, the nut tapered portion 433T is formed so that the inner diameter gradually decreases from the first side toward the second side. The nut tapered portion 433T corresponds to the inclination angle of the cap tapered portion 513, which will be described later. The nut tapered portion 433T faces the cap tapered portion 513.

[0028] The piston nut 43 is supported by the rod 20 by fixing the female thread 43R to the male thread 213 of the rod 20. The piston nut 43 also has a crimped portion 43K at the first end of the cylindrical portion 433. The crimped portion 43K is formed by plastically deforming the end of the cylindrical portion 433, which was formed in a straight shape, by roll crimping. The piston nut 43 of this embodiment holds the various members that make up the damping force change portion 40 and the piston portion 30 to the rod 20. Furthermore, the communication passage 43H connects the pressure chamber 47 (described later) and the pressure adjustment chamber 500, and forms an oil flow path between the pressure chamber 47 and the pressure adjustment chamber 500.

[0029] The spool 44 has a generally cylindrical shape. The second side of the spool 44 protrudes radially inward, and the columnar portion 431 of the piston nut 43 is inserted into the first side. The spool 44 is formed so as to be able to come into contact with the adjusting valve 41 on the second side, and is biased on the second side by a support spring 46. The spool 44 applies a force to the adjusting valve 41 to press the adjusting valve 41 against the end of the second valve stopper 353 on the first side. The spool 44 forms a pressure chamber 47 together with the piston nut 43 and the adjusting valve 41 .

[0030] The O-ring 45 is attached to the piston nut 43 and supports the spool 44 so that it can move in the axial direction. As shown in Fig. 4, the support spring 46 is formed in a ring shape and has a plurality of protrusions 46a that protrude outward from the outer periphery. The inner periphery of the support spring 46 is supported by the annular protrusion 432 of the piston nut 43. As shown in Fig. 6, the support spring 46 biases the spool 44 toward the second side.

[0031] (End Cap 51) The end cap 51 is formed with an outer diameter slightly smaller than the inner diameter of the cylindrical portion 433 of the piston nut 43. The end cap 51 is inserted into the cylindrical portion 433 of the piston nut 43. When the end cap 51 is inserted into the cylindrical portion 433 of the piston nut 43, a pressure adjustment chamber 500, which is a cylindrical space, is formed between the end cap 51 and the cylindrical portion 433. A float valve 52 and a pressure adjustment chamber spring 53 are housed in this pressure adjustment chamber 500.

[0032] The end cap 51 has a valve facing portion 511 provided on the second side and facing the float valve 52, and a cap tapered portion 513 provided on the second side.

[0033] The valve facing portion 511 has an annular protrusion 51C formed on the second side, a deformation restricting portion 51G formed on the second side, and a through hole 51H formed to extend in the axial direction. As shown in FIG. 6, the valve facing portion 511 supports the float valve 52. The annular protrusion 51C protrudes in an annular shape toward the second axial side. The main body 56 of the float valve 52 is sandwiched between the annular protrusion 51C and the pressure adjustment chamber spring 53.

[0034] The deformation restricting portion 51G is provided more inward than the annular protruding portion 51C and is recessed toward the first side relative to the annular protruding portion 51C. When the float valve 52 is flexibly deformed, the deformation restricting portion 51G allows the float valve 52 to deform by a certain amount, and restricts deformation beyond the certain amount.

[0035] The through-hole 51H is provided so as to penetrate through the valve opposing portion 511. A plurality of (for example, two) through-holes 51H are provided. The second side of the through-hole 51H opens at the deformation restricting portion 51G, and the first side opens at the first chamber Y1. The through-hole 51H allows oil to circulate between the pressure adjusting chamber 500 and the first chamber Y1.

[0036] The cap tapered portion 513 is formed radially outward of the annular protrusion 51C. The cap tapered portion 513 is inclined toward the second side with respect to the axial direction. That is, the cap tapered portion 513 is formed so that the outer diameter gradually decreases from the first side toward the second side. The cap tapered portion 513 corresponds to the inclination angle of the nut tapered portion 433T. The cap tapered portion 513 faces the nut tapered portion 433T.

[0037] (Float valve 52) The float valve 52 has a circular metal main body 56 and a rubber part 57 made of rubber and attached to the outer periphery of the main body 56. The float valve 52 is biased toward the end cap 51 by a pressure adjustment chamber spring 53. However, the float valve 52 can move against the biasing force of the pressure adjustment chamber spring 53, and can be displaced in the axial direction and in a direction perpendicular to the axial direction.

[0038] The diameter of the main body 56 is larger than the diameter of the annular protrusion 51C of the end cap 51 and smaller than the diameter of the inner circumferential surface of the cylindrical portion 433 of the piston nut 43. The main body 56 is a thin, plate-like member that is easily elastically deformed. Therefore, when the main body 56 receives pressure from the pressure adjustment chamber 500 while in contact with the annular protrusion 51C of the end cap 51, it can deform until it comes into contact with the deformation restriction portion 51G of the end cap 51.

[0039] The rubber portion 57 has an annular base end portion 571 baked onto the outer periphery of the main body portion 56, and a protruding portion 572 that protrudes cylindrically from the outer periphery of the base end portion 571 to the second side. The diameter of the outer periphery of the protruding portion 572 is equal to or larger than the diameter of the inner periphery of the cylindrical portion 433 of the piston nut 43. The thickness of the rubber portion 57 can be set as appropriate. When the pressure in the pressure adjustment chamber 500 is higher than the pressure in the first chamber Y1, the protruding portion 572 of the rubber portion 57 comes into contact with the inner circumferential surface of the cylindrical portion 433 of the piston nut 43, sealing the pressure adjustment chamber 500. On the other hand, when the pressure in the first chamber Y1 is higher than the pressure in the pressure adjustment chamber 500, the protruding portion 572 bends inward, allowing oil to flow from the first chamber Y1 to the pressure adjustment chamber 500.

[0040] The float valve 52 configured as described above deforms or displaces during the extension stroke or compression stroke, thereby changing the volume of the pressure adjustment chamber 500. Also, by closing or opening the through-hole 51H of the end cap 51, the float valve 52 blocks or allows the flow of oil between the pressure adjustment chamber 500 and the first chamber Y1 side.

[0041] As shown in FIG. 5, the pressure adjustment chamber spring 53 has a plate-shaped annular portion 53a, and a plurality of upward spring legs 53b and downward spring legs 53c that are provided radially. As shown in FIG. 6, the pressure adjustment chamber spring 53 has its upward spring leg 53b attached to face the first end face of the cylindrical portion 431 of the piston nut 43, and its downward spring leg 53c biases the float valve 52 toward the annular protrusion 51C.

[0042] As shown in FIG. 6, the end cap 51, the float valve 52, and the pressure adjustment chamber spring 53 are held by the piston nut 43 by a crimped portion 43K formed on the first side of the piston nut 43.

[0043] The crimped portion 43K presses the end cap 51 toward the second side. The axial force generated by this crimped portion 43K presses the cap tapered portion 513 of the end cap 51 against the nut tapered portion 433T of the piston nut 43. This secures the end cap 51 to the piston nut 43 without rattle, improving the sealing performance at the contact points between the end cap 51 and the piston nut 43.

[0044] When the piston portion 30 and the damping force changer 40 are viewed from the first side, the crimped portion 43K is formed over the entire circumferential area and presses the end cap 51 against the piston nut 43 side.

[0045] Next, the operation of the shock absorber 2 will be described. FIG. 7 is a diagram illustrating the operation of the piston portion 30 and the bottom portion 60 during the compression stroke and the extension stroke.

[0046] 7, during the compression stroke in which the rod 20 moves toward the first side relative to the cylinder 11 as indicated by the white arrow, the oil pressure in the first chamber Y1 rises. This opens the compression side damping valve portion 322 that blocks the compression side oil passage 342, and oil flows into the second chamber Y2 through the compression side oil passage 342 as indicated by arrow A. This flow of oil from the first chamber Y1 to the second chamber Y2 is throttled by the compression side damping valve portion 322, and damping force during the compression stroke of the shock absorber 2 is obtained. Furthermore, the oil in the first chamber Y1, whose pressure has increased due to the axial movement of the piston 31 toward the first side, opens the valve 62 in the bottom portion 60. Then, the oil in the first chamber Y1 flows out into the reservoir chamber R, as shown by arrow B.

[0047] 7, during the extension stroke in which the rod 20 moves toward the second side relative to the cylinder 11 as indicated by the white arrow, the first chamber Y1 becomes short of oil by that volume, resulting in negative pressure. As a result, the oil in the second chamber Y2 passes through the extension-side oil passage 341 of the piston portion 30, opens the extension-side damping valve portion 321 that closes this extension-side oil passage 341, and flows into the first chamber Y1 as indicated by arrow C. The flow of oil from the second chamber Y2 to the first chamber Y1 is throttled by the extension-side damping valve portion 321 of the piston portion 30, and the damping force during the extension stroke of the shock absorber 2 is obtained. Furthermore, when the piston 31 moves to the second side, the oil in the reservoir chamber R opens the valve 63 as shown by the arrow D and flows into the first chamber Y1.

[0048] FIG. 8 is a diagram showing an example of the operation of the damping force changing unit 40 during the extension stroke. When the rod 20 moves with a small amplitude, during the extension stroke, oil that has flowed into the bypass passage 25 from the second chamber Y2 (see FIG. 7) passes through the orifice 42S of the throttle member 42 and the communication passage 43H of the piston nut 43 and flows into the pressure adjustment chamber 500. At this time, in the pressure adjustment chamber 500, the main body 56 of the float valve 52 bends toward the deformation restriction portion 51G, increasing the volume of oil that can be accommodated, making it difficult for the oil pressure in the pressure adjustment chamber 500 to increase. Therefore, the force that the spool 44 provided on the pressure adjustment chamber 500 applies to press the adjustment valve 41 toward the second valve stopper 353 also decreases. Then, the adjustment valve 41 opens the recess 353c of the second valve stopper 353. The oil flowing through the bypass passage 25 flows out from the recess 353c of the second valve stopper 353 into the first chamber Y1. In this way, when the rod 20 moves with a small amplitude, a flow of oil occurs that bypasses the extension-side oil passage 341 (see FIG. 7) of the piston portion 30 (see FIG. 7). Therefore, when the rod 20 moves with a small amplitude, during the extension stroke, in addition to the oil flow in the extension-side oil passage 341 of the piston portion 30 (see Figure 7), oil also flows through the bypass passage 25, and the damping force generated in the piston portion 30 becomes smaller.

[0049] On the other hand, when the rod 20 moves with a large amplitude, during the extension stroke, oil that has flowed from the second chamber Y2 (see FIG. 7) into the bypass passage 25 passes through the orifice 42S of the throttle member 42 and the communication passage 43H of the piston nut 43 and flows into the pressure adjustment chamber 500. When the rod 20 moves with a large amplitude, the main body 56 of the float valve 52 immediately bends up to the deformation restriction portion 51G in the pressure adjustment chamber 500, and the contact pressure of the rubber portion 57 against the inner circumferential surface of the cylindrical portion 433 increases, causing the oil in the pressure adjustment chamber 500 to become pressurized. Therefore, the force of the spool 44 provided on the pressure adjustment chamber 500 side pressing the adjustment valve 41 toward the second valve stopper 353 increases. Then, the adjustment valve 41 blocks the recess 353c of the second valve stopper 353. Therefore, when the rod 20 moves with a large amplitude, during the extension stroke, oil does not flow from the second chamber Y2 to the first chamber Y1 via the bypass path 25, and only oil flows through the extension-side oil path 341 of the piston portion 30 (see Figure 7), so the damping force generated in the piston portion 30 becomes large.

[0050] On the other hand, during the compression stroke, the pressure in the first chamber Y1 becomes higher than the pressure in the pressure adjustment chamber 500. This causes oil to flow from the first chamber Y1 into the pressure adjustment chamber 500 through the through hole 51H provided in the end cap 51.

[0051] As described above, when the rod 20 moves slightly, for example, when the vehicle is traveling on a rough road, the shock absorber 2 reduces the damping force, thereby improving the ride comfort of the vehicle. On the other hand, when the rod 20 moves significantly, for example, when the vehicle is traveling around a curve, the shock absorber 2 increases the damping force, thereby improving the handling stability of the vehicle.

[0052] Next, a structure for improving the sealing performance of the pressure adjusting chamber 500 will be described in detail. FIG. 9 is a diagram showing an example of how the damping force changer 40 is assembled. Figure 10 shows an example of the state of the piston nut 43 before and after the piston nut 43 is pressurized by the pressurizing tool 100. Figure 10(a) shows an example of the state of the piston nut 43 before pressurization, and is an example of an enlarged view of part X in Figure 9. Figure 10(b) shows an example of the state of the piston nut 43 after pressurization. Figure 11 is a diagram showing an example of a pressure tool 100. Figure 11(a) is an external view of the pressure tool 100 as seen in the direction of the center line, and Figure 11(a) is a diagram showing an example of a cross section of part XIb-XIb in Figure 11(b).

[0053] 8, during the extension stroke, the amount of oil flowing from the second chamber Y2 into the pressure adjustment chamber 500 via the bypass passage 25, the orifice 42S of the throttle member 42, and the communication passage 43H of the piston nut 43 is adjusted, thereby adjusting the pressure of the oil in the pressure adjustment chamber 500 and adjusting the damping force generated in the piston portion 30. Therefore, if the oil that has flowed into the bypass passage 25 from the second chamber Y2 flows into the pressure adjustment chamber 500 through the spiral passage Rs formed between the male thread 213 of the rod 20 and the female thread 43R of the piston nut 43, it becomes difficult to adjust the oil pressure in the pressure adjustment chamber 500 with high precision.

[0054] In this embodiment, as shown in Fig. 10, the piston nut 43 has a plastic flow portion 435 to prevent oil from passing through the spiral passage Rs formed between the male thread 213 of the rod 20 and the female thread 43R of the piston nut 43. Below, an embodiment of forming the plastic flow portion 435 in the piston nut 43 will be described using Figs. 9, 10 and 11.

[0055] As shown in FIG. 9(a), first, the first valve stopper 351, the compression side damping valve portion 322, the piston 31, the extension side damping valve portion 321, the second valve stopper 353, the adjustment valve 41, the throttle member 42, the spool 44, the support spring 46, the O-ring 45, the piston nut 43, etc. are assembled to the first side mounting portion 21 of the rod 20.

[0056] Thereafter, as shown in FIG. 9(b), a pressure tool 100 is used to apply pressure to the first end face 436 of the columnar portion 431 of the piston nut 43, thereby forming a plastic flow portion 435 (see FIG. 10). 11, the pressure tool 100 has a base 110 having an opposing surface 111 that faces the end surface 436 of the piston nut 43 (see FIG. 9), and a protrusion 120 that protrudes from the opposing surface 111. In this embodiment, the base 110 is cylindrical, and the protrusion 120 is provided around the entire circumference of the center line of the base 110 and protrudes in the direction of the center line of the base 110. When the protrusion 120 is cut along a plane passing through the center line, it has a triangular shape with the tip 121 as its apex. The diameter of the tip 121 of the protrusion 120 is larger than the diameter of the female thread 43R of the piston nut 43 (see FIG. 9).

[0057] As shown in FIG. 9( b), the pressure tool 100 is placed relative to the piston nut 43 so that the center line of the base 110 of the pressure tool 100 coincides with the center line of the rod 20 (i.e., the center line of the piston nut 43). Then, the tip 121 of the protrusion 120 of the pressure tool 100 is brought into abutment with the end face 436 of the piston nut 43. The pressure tool 100 is then moved so that the opposing surface 111 of the base 110 of the pressure tool 100 approaches the end face 436 of the piston nut 43, and the protrusion 120 of the pressure tool 100 presses the end face 436 of the piston nut 43 (see FIG. 10( b)). As a result, a recess 434 is formed in the portion of the piston nut 43 pressed by the protrusion 120, and plastic flow occurs around the recess 434. For example, inward plastic flow occurs in the portion of the piston nut 43 inside the portion pressed by the protrusion 120, and outward plastic flow occurs in the portion outside the portion pressed by the protrusion 120.

[0058] In the state shown in FIG. 10( a) before pressure is applied by the pressure tool 100, the spiral passage Rs between the male thread 213 of the rod 20 and the female thread 43R of the piston nut 43 is formed from one end (e.g., the end on the first side) in the center line direction of the male thread 213 to the other end (e.g., the end on the second side). Then, as shown in FIG. 10( b), plastic flow occurs in a portion inside the portion pressurized by the protrusion 120, and a plastic flow portion 435 is formed that crushes the end of the spiral passage Rs on the side of the pressure tool 100. In other words, the person assembling the damping force changer 40 presses the end face 436 of the piston nut 43 with the pressure tool 100 to form the plastic flow portion 435 so that the spiral passage Rs does not continue from one end (e.g., the end on the first side) in the center line direction to the other end (e.g., the end on the second side).

[0059] Then, as shown in Figure 9(c), the pressure adjustment chamber spring 53, the float valve 52 and the end cap 51 are inserted inside the cylindrical portion 433 of the piston nut 43, and the first end of the cylindrical portion 433 is subjected to roll crimping processing to form the crimped portion 43K.

[0060] The height of the protrusion 120 of the pressurizing tool 100 (in other words, the size in the direction of the center line of the base 110) is set so that when the opposing surface 111 of the pressurizing tool 100 is brought close to the end face 436 of the piston nut 43 to form a plastic flow portion 435 so as to crush the spiral passage Rs, as shown in FIG. 10(b) , the opposing surface 111 does not come into contact with the first-side mounting portion 21 of the rod 20. For example, the height of the protrusion 120 can be 1 / 10 to 1 / 5 of the size in the direction of the center line of the female thread 43R of the piston nut 43. The diameter of the tip end 121 of the protrusion 120 is set to a size that, when pressure is applied so that the opposing surface 111 does not come into contact with the first-side mounting portion 21 of the rod 20, plastic flow occurs in a portion inside the portion pressed by the protrusion 120, crushing the end of the spiral passage Rs on the pressurizing tool 100 side. For example, the diameter of the tip end 121 of the protrusion 120 can be 1.05 to 1.2 times the diameter of the internal thread 43R of the piston nut 43.

[0061] The piston nut 43 formed as described above is an example of a nut member having a female thread 43R for fastening the male thread 213. The piston nut 43 has a fastening portion between the male thread 213 and the female thread 43R connected to a pressure adjustment chamber 500 (an example of a liquid-tight chamber) in which oil (an example of a liquid) is sealed, and has a plastic flow portion 435 formed by plastic flow around the female thread 43R.

[0062] With the piston nut 43 configured as described above, the plastic flow portion 435 can seal the spiral passage Rs between the male thread 213 and the female thread 43R. As a result, oil is prevented from flowing into the pressure adjustment chamber 500 through the gap between the male thread 213 and the female thread 43R. Furthermore, there is no need to apply adhesive to seal the gap between the male thread 213 and the female thread 43R. If adhesive were applied, it would take a long time (e.g., 24 hours) for the adhesive to dry. Therefore, by not applying adhesive, the assembly time can be shortened. Furthermore, if adhesive were applied, the applied adhesive would overflow from the gap between the male thread 213 and the female thread 43R and harden, which could cause the hardened adhesive to float in the oil. However, by not applying adhesive, it is possible to prevent the hardened adhesive from floating in the oil. Furthermore, with the piston nut 43, loosening of the fastened portion between the female thread 43R of the piston nut 43 and the male thread 213 of the rod 20 is prevented.

[0063] Here, in the piston nut 43, a recess 434 is formed by pressurization in a portion around the female thread 43R on the pressure adjustment chamber 500 side, and the plastic flow portion 435 is formed inside the recess 434. Therefore, the plastic flow portion 435 is likely to be formed near the female thread 43R with high accuracy. Furthermore, in the piston nut 43, the recess 434 is formed around the entire circumference of the female thread 43R, which makes it possible to seal the spiral passage Rs between the male thread 213 and the female thread 43R with high reliability.

[0064] The pressure tool 100 configured as described above is a pressure tool used to apply pressure to the periphery of the female thread 43R of the piston nut 43, which has the female thread 43R formed therein and to which the male thread 213 is fastened. The pressure tool 100 includes a base 110 having an opposing surface 111 that faces an end face 436 of the piston nut 43 in the centerline direction, and a protrusion 120 provided around the female thread 43R so as to protrude from the opposing surface 111 in the centerline direction. The pressure tool 100 configured as described above makes it possible to form the plastic flow portion 435 in the piston nut 43 with high accuracy.

[0065] Here, the protrusion 120 is formed all around the female thread 43R, which makes it possible to form the plastic flow portion 435 all around the female thread 43R, and to seal the spiral passage Rs between the male thread 213 and the female thread 43R with high reliability.

[0066] (Modifications of the cross-sectional shape of the protrusion 120) 12(a) and 12(b) are diagrams showing examples of modified cross-sectional shapes of the protrusions 120. FIG. The shape of the projection 120 when cut along a plane passing through the center line of the base 110 is not limited to the isosceles triangle shape shown in FIG. 11(b).

[0067] The protrusion 120 may be a right-angled triangle as shown in Fig. 12(a). Furthermore, when the protrusion 120 is a right-angled triangle, it is preferable that the tip 121 of the protrusion 120 is provided on the inside as shown in Fig. 12(a). This makes it possible to form the plastic flow portion 435 (see Fig. 10) around the female thread 43R of the piston nut 43 with high accuracy, and to seal the spiral passage Rs (see Fig. 10) with high accuracy. 12(b), the protrusion 120 may be rectangular. Even if the protrusion 120 is rectangular, a plastic flow portion 435 can be formed around the female thread 43R of the piston nut 43, and the spiral passage Rs can be sealed.

[0068] (Modifications of the circumferential shape of the protrusion 120) 13(a) and 13(b) are diagrams showing examples of modified circumferential shapes of the protrusions 120. FIG. The shape of the protrusion 120 when viewed in the direction of the center line of the base 110 is not limited to a circle. In other words, the protrusion 120 does not have to be provided around the entire center line of the base 110.

[0069] A plurality of protrusions 120 may be provided partially in the circumferential direction around the center line of the base 110. For example, as shown in Fig. 13(a), two protrusions 120 may be provided so as to extend in the circumferential direction. Alternatively, as shown in Fig. 13(b), three protrusions 120 may be provided so as to extend in the circumferential direction. In one example, the three protrusions 120 are provided at equal intervals.

[0070] According to the protrusion 120 of the modified example shown in Figures 13(a) and 13(b), a plurality of recesses 434 (see Figure 10) of the piston nut 43 are formed partially in the circumferential direction around the female thread 43R (see Figure 10). Further, a plurality of plastic flow portions 435 (see Figure 10) are formed partially in the circumferential direction around the female thread 43R. As a result, it is possible to crush a portion of the spiral passage Rs between the male thread 213 (see Figure 10) and the female thread 43R, and therefore it is possible to seal the spiral passage Rs (see Figure 10).

[0071] Second Embodiment FIG. 14 is a diagram showing an example of a pressure tool 200 according to the second embodiment. The pressure tool 200 according to the second embodiment differs from the pressure tool 100 according to the first embodiment in that it further includes a protrusion 230 provided at the center of the opposing surface 111 of the base 110 so as to protrude from the opposing surface 111 in the direction of the center line of the base 110. The differences from the first embodiment will be described below. The same components in the first and second embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

[0072] Here, the rod 20 has a central recess 215 formed in the center of the first side end of the first side mounting portion 21, which is a centering recess used when performing cutting processing to form the rod 20. The convex portion 230 is the portion that is inserted into the central recess 215 of the rod 20 when the tip portion 121 of the protrusion 120 of the pressure tool 200 is abutted against the end face 436 of the piston nut 43 to form a plastic flow portion 435 (see Figure 10) in the piston nut 43.

[0073] The shape of the protrusion 230 is not particularly limited. For example, if the shape of the first end of the central recess 215 of the rod 20 is cylindrical, the protrusion 230 may be cylindrical. The diameter of the protrusion 230 is preferably the same as or slightly smaller than the diameter of the central recess 215 of the rod 20. This makes it easier to align the center position of the protrusion 120 of the pressure tool 200 with the center position of the female thread 43R of the piston nut 43 when viewed in the direction of the center line of the base 110. In other words, the protrusion 230 functions as a positioning device when the tip end 121 of the protrusion 120 of the pressure tool 200 is abutted against the end face 436 of the piston nut 43 to form the plastic flow portion 435 in the piston nut 43.

[0074] The pressure tool 200 configured as described above further includes a protrusion 230 (an example of a protrusion) that protrudes from the opposing surface 111 in the center line direction and is fitted into a central recess 215 (an example of a recess) formed in the center of the rod 20, which is an example of a member having a male thread 213 to which the piston nut 43 is fastened. The distance between the protrusion 120 of the pressure tool 200 and the protrusion 230 is greater than the distance from the protrusion 230 to the female thread 43R.

[0075] According to the pressurizing tool 200 configured as described above, the convex portion 230 functions as a positioning element when forming the plastic flow portion 435 in the piston nut 43, making it easier to form a uniform plastic flow portion 435 around the female thread 43R. As a result, the spiral passage Rs between the male thread 213 and the female thread 43R is sealed with high accuracy. Note that the shape of the convex portion 230 is not limited to a cylindrical shape, and it may be a square prism or a cone. [Explanation of symbols]

[0076] 1...suspension device, 2...shock absorber, 10...cylinder portion, 20...rod, 30...piston portion, 40...damping force change portion, 43...piston nut (an example of a nut member), 43R...female thread, 100, 200...pressure tool, 110...base portion, 111...opposing surface, 120...projection, 213...male thread, 215...central recess (an example of a recess), 230...convex portion, 434...recess, 435...plastic flow portion, 436...end surface, 500...pressure adjustment chamber, Y1...first chamber, Y2...second chamber

Claims

1. A nut member having an internal thread to which an external thread is fastened, The tightening portion of the male screw and the female screw is connected to a liquid-tight chamber, which is a portion where the liquid is sealed, and at least a part of the periphery of the female screw has a plastic flow portion formed by plastic flow. Nut component.

2. A recess is formed around the female thread at a portion on the liquid-tight chamber side by pressurization, The plastic flow portion is formed inside the recess. The nut member according to claim 1 .

3. The recess is formed around the entire circumference of the female thread. The nut member according to claim 2 .

4. The recessed portion is formed in a plurality of portions in a circumferential direction around the female thread. The nut member according to claim 2 .

5. The nut member according to any one of claims 1 to 4, a rod having an external thread formed thereon to which the nut member is fastened; A shock absorber comprising:

6. A pressure tool used to apply pressure to at least a portion of a periphery of a female thread in a nut member having a female thread formed therein onto which a male thread is tightened, a base portion having an opposing surface facing an end surface of the nut member in a center line direction; a protrusion provided on at least a portion of the periphery of the female thread so as to protrude from the opposing surface in the center line direction; A pressure tool comprising:

7. The protrusion is provided around the entire circumference of the female thread. The pressure tool according to claim 6.

8. The protrusions are provided in plural in a circumferential direction partially around the female thread. The pressure tool according to claim 6.

9. a protrusion that protrudes from the opposing surface in the direction of the center line and is fitted into a recess that is formed in the center of a member having a male thread to which the nut member is fastened, The distance of the protrusion from the convex portion is greater than the distance from the convex portion to the female screw. A pressure tool according to any one of claims 6 to 8.

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