JP2020008150A - Shock absorption device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorber which suppresses deterioration of a cushion rubber and improves durability of the cushion rubber more than ever before even when the diameter expansion of the cushion rubber is restricted by a coil spring. And A shock absorber (4) having a rod (3) inserted in a cylinder (2) so as to be able to move in and out in an axial direction, a coil spring (S) arranged on the outer periphery of the shock absorber (4) and biasing the shock absorber (4) in an extension direction, The cushion rubber 5 is attached to the outer circumference of the rod 3 and cushions the shock absorber 4 at the time of the most contraction. The coil spring S has a coarse winding portion S2 and a pitch smaller than that of the coarse winding portion S2. The densely wound portion S1 has a restricting portion 21 facing the cushion rubber 5, and the restricting portion 21 has a surface 22 that can be cut off on the inner peripheral side along the axial direction. [Selection diagram]

Description

  The present invention relates to a shock absorber.

  A conventional shock absorber is, for example, a shock absorber that is interposed between a vehicle body and an axle in a vehicle for the purpose of suppressing vehicle body vibration, and includes a cylinder and a rod that moves in and out of the cylinder. Some include a coil spring disposed on the outer periphery of the cylinder to bias the shock absorber in the extension direction.

  Further, the shock absorber includes a cushion rubber attached to the outer periphery of the rod, and a stopper attached to the rod side end of the cylinder. When the shock absorber fully contracts, the cushion rubber comes into contact with the stopper to elastically deform, A reaction force is generated to reduce the shock when the shock absorber is contracted most.

  Further, there is a cushion rubber provided on the outer periphery of the cushion rubber, which controls a magnitude of a reaction force generated by the cushion rubber at the time of the most contraction of the shock absorber and provides a spring guide for preventing the cushion rubber from being bitten by the coil spring. Then, the number of parts increases and the assemblability deteriorates.

  In view of this, a shock absorber has been developed in which the expansion of the diameter of the cushion rubber due to elastic deformation is restricted on the inner periphery of the coil spring, and the spring guide is omitted (see Patent Document 1).

  Specifically, the coil spring is a so-called multi-stage coil spring having a coarsely wound portion and a densely wound portion having a smaller pitch than the coarsely wound portion, and the densely wound portion is arranged at a position facing the cushion rubber. And, before the cushion rubber is crushed, the tightly wound portion is brought into close contact, and the outer diameter of the crushed cushion rubber at the time of the most contraction of the shock absorber is brought into contact with the inner periphery of the closely wound portion, The tightly wound part regulates the expansion of the cushion rubber.

JP 2013-72455 A

  However, in the conventional shock absorber, since the coil spring is formed of a wire having a circular cross section, if one turn of the wire is used as a coil on the inner periphery of the densely wound portion, as shown in FIG. A spiral depression 201 is formed between the coil parts 200 at the time of close contact. Therefore, when the tightly wound portion comes into close contact with the inner peripheral surface of the closely wound portion of the coil spring, unevenness due to the depression 201 is formed.

  Therefore, in the conventional shock absorber, when the cushion rubber is crushed and comes into contact with the inner peripheral surface of the closely wound portion, the cushion rubber bites into the unevenness formed on the inner peripheral surface of the closely wound portion and deteriorates. And the durability of the cushion rubber has been reduced.

  If the coil spring is formed of a wire having a square cross section, the depression 201 cannot be formed between the coil portions when the tightly wound portion is in close contact. However, when a coil spring is formed from a wire having a rectangular cross section, it is necessary to spirally wind the wire so as to prevent the wire from being twisted so that the coil portions come into surface contact with each other. Therefore, when a coil spring is formed from a wire having a rectangular cross section, residual stress is generated inside the coil spring, and the residual stress tends to cause the coil portions to be shifted in the radial direction and to come into contact with each other when the tightly wound portion is in close contact.

  Then, when the coil portions come into contact with each other while being shifted in the radial direction, a step is formed between the coil portions. Therefore, even in a coil spring formed of a wire having a quadrangular cross section, when the close wound portion is in close contact, the unevenness due to the step is formed on the inner peripheral surface of the close wound portion. Therefore, even if the cross section of the wire is square, the problem that the durability of the cushion rubber is reduced is not solved.

  Therefore, an object of the present invention is to provide a shock absorber in which even when the diameter of the cushion rubber is restricted by a coil spring, the cushion rubber hardly deteriorates and the durability of the cushion rubber is improved as compared with the related art.

  Means for solving the above problems include a shock absorber having a rod inserted into and out of the cylinder so as to be able to freely move in and out of the cylinder, and a coil spring disposed on the outer periphery of the shock absorber and for urging the shock absorber in the extension direction. And a cushion rubber attached to the outer periphery of the rod to relieve the shock at the time of the most contraction of the shock absorber, wherein the coil spring has a coarsely wound portion and a smaller pitch than the coarsely wound portion. A tightly-wound portion having a regulating portion facing the cushion rubber, wherein the regulating portion has a surface formed by cutting off the inner peripheral side along the axial direction.

  As another means, a shock absorber having a rod inserted into and out of the cylinder so as to be able to freely move in and out of the cylinder, a coil spring arranged on the outer periphery of the shock absorber to urge the shock absorber in the extension direction, and the rod A cushion rubber attached to the outer periphery of the shock absorber to reduce the shock at the time of the most contraction of the shock absorber, wherein the coil spring has a coarsely wound portion, and a pitch smaller than the coarsely wound portion is set to the cushion rubber. A tightly wound portion having an opposing regulating portion, and a depth of a dent formed on an inner peripheral side between the coil portions in the regulating portion when the tightly wound portion is in close contact with the coarsely wound portion. Wherein the depth of the sparsely wound portion is less than the depth of a recess formed on the inner peripheral side between the coil portions.

  Further, a buffer device in which the inner peripheral surfaces of the respective coil portions of the regulating portion are flush with each other when the tightly wound portion is in close contact with each other. According to this configuration, since the unevenness is not formed on the inner peripheral surface of the regulating portion when the tightly wound portion is in close contact, the cushion rubber is less likely to deteriorate.

  Further, a buffer device in which the close-wound portion is always in close contact may be used. According to this configuration, since the tightly wound portion is always in close contact, no gap is formed between the coil portions of the wire constituting the regulating portion, and the cushion rubber is damaged when the cushion rubber comes into contact with the regulating portion. Not stick.

  Further, the cushion rubber may be a cushioning device in which the tightly wound portion comes into close contact before the cushion rubber is crushed and expanded to abut on the regulating portion. According to this configuration, when the cushion rubber is crushed and expanded to come into contact with the restricting portion, the tightly wound portion is already in close contact, so that a gap is formed between the coil portions of the wire constituting the restricting portion. No, the cushion rubber is not damaged when the cushion rubber comes into contact with the regulating portion.

  ADVANTAGE OF THE INVENTION According to the shock absorber of this invention, even when restricting the diameter expansion of a cushion rubber with a coil spring, since the cushion rubber does not deteriorate easily, the durability of a cushion rubber improves.

It is a front sectional view showing the whole shock absorber concerning this embodiment. 2 is an enlarged partial cross-sectional view of a main part of FIG. 1, wherein FIG. 2A shows a case where the shock absorber is in an extended state, and FIG. 2B is a case where the shock absorber is in a most contracted state. Is shown. It is a figure which shows the state which looked at the densely wound part of the coil spring before processing from the axial direction. FIG. 3 is a partially enlarged front sectional view of a closely wound portion of the coil spring according to the present embodiment. FIG. 13 is a partially enlarged front cross-sectional view illustrating a first modification of the coil spring according to the present embodiment, illustrating a depth of a groove between coil portions of a densely wound portion and a depth of a groove between coil portions of a coarsely wound portion. is there. FIG. 13 is a partially enlarged front cross-sectional view illustrating a second modification of the coil spring according to the present embodiment, illustrating a depth of a groove between coil portions of a densely wound portion and a depth of a groove between coil portions of a coarsely wound portion. is there. It is front sectional drawing which expands and shows a part of close coiled part of the conventional coil spring.

  The present embodiment will be described below with reference to the drawings. The same reference numbers throughout the several figures indicate the same or corresponding parts.

  The shock absorber 1 includes a shock absorber 4 having a cylinder 2 and a rod 3 inserted into and out of the cylinder 2 so as to be able to move in and out in the axial direction. The shock absorber 4 is arranged on the outer periphery of the shock absorber 4 and urges the shock absorber 4 in the extension direction. The vehicle includes a coil spring S and a cushion rubber 5 attached to the outer periphery of the rod 3 to reduce an impact at the time of the shock absorber 4 being most contracted.

  Next, the shock absorber 4 will be described in detail. As shown in FIG. 1, an annular rod guide 6 that closes the cylinder 2 and supports the rod 3 is provided at the lower end in the figure of the cylinder 2 with a top cylinder. The rod guide 6 is fixed to the cylinder 2 by rolling the cylinder 2 from the outer peripheral side. Further, an oil seal 7, a dust seal 8, and a stopper 9 are inserted on the inner periphery of the lower end of the cylinder 2 and below the rod guide 6 in FIG. The oil seal 7, the dust seal 8 and the stopper 9 are fixed to the cylinder 2 by being clamped by a crimping portion 2 a formed by crimping the lower end of the cylinder 2 inward and the rod guide 6.

  The oil seal 7 is annular and is stacked below the rod guide 6 in FIG. 1, and slides on the outer periphery of the rod 3 to prevent the liquid attached to the outer periphery of the rod 3 from leaking.

  The dust seal 8 is annular, and is stacked below the oil seal 7 in FIG. 1. The dust seal 8 slides on the outer periphery of the rod 3 to scrape off the foreign matter attached to the outer periphery of the rod 3, and Prevents foreign matter from entering.

  The stopper 9 has an annular main body portion 9a sandwiched between the dust seal 8 and the caulking portion 2a, and a protruding end protruding downward in the drawing from the inner peripheral end of the main body portion 9a and arranged inside the caulking portion 2a. It has a portion 9b. Further, as shown in FIG. 1, the protruding end portion 9b of the stopper 9 and the caulking portion 2a of the cylinder 2 are set at the same height. Thus, when the shock absorber 4 is most contracted, the stopper 9 comes into contact with the protruding end 9 b against the cushion rubber 5 and compresses the cushion rubber 5.

  As shown in FIG. 1, a vehicle body side bracket 14 for connecting the cylinder 2 to the vehicle body side of the vehicle is welded and fixed to the upper end of the cylinder 2 in the drawing.

  Returning, a free piston 10 slidable with respect to the inner circumference of the cylinder 2 is inserted into the cylinder 2, and a liquid chamber R filled with liquid and a gas chamber G filled with gas are filled in the cylinder 2. Is divided into

  Further, in the present embodiment, the liquid filled in the cylinder 2 is hydraulic oil, but the liquid may be another liquid such as water, an aqueous solution, an electrorheological fluid, or a magnetic viscous fluid.

  Further, a piston 11 that divides the inside of the liquid chamber R into two chambers, a growth chamber R1 and a compression chamber R2, is connected to the upper end of the rod 3 in FIG.

  The piston 11 is formed with an expansion-side passage 11a and a compression-side passage 11b that communicate the expansion-side chamber R1 and the compression-side chamber R2. The piston 11 has an expansion valve 12 laminated on the compression side chamber of the piston 11 to provide resistance to the flow of liquid passing through the expansion side passage 11a, and a compression side passage 11b laminated on the expansion side of the piston 11 A pressure side valve 13 is provided to provide resistance to the flow of liquid passing through the pressure. When the shock absorber 4 expands and contracts, when the liquid moves through the expansion side passage 11a or the compression side passage 11b from one of the expansion side chamber R1 and the compression side chamber R2, which is compressed in the cylinder 2, to the other to expand, The expansion side valve 12 or the compression side valve 13 provides resistance to the flow, whereby the shock absorber 4 exerts a damping force.

  Further, a change in the volume of the working fluid due to a change in the temperature of the cylinder due to the rod projecting and retracting volume due to the expansion and contraction operation of the shock absorber 4 and a change in the volume of the working fluid due to the axial movement of the free piston 10 of the air chamber G are compensated. .

  In the present embodiment, the shock absorber 4 is a single cylinder type. However, the free piston 10 is eliminated, a base valve is provided in the cylinder 2, and an outer cylinder that covers the cylinder 2 is provided on the outer periphery of the cylinder 2. Thus, a multi-cylinder type in which a reservoir is formed in an annular gap between the cylinder 2 and the outer cylinder may be set. In the case of a multi-cylinder type, a change in the cylinder volume corresponding to the rod projecting / retracting volume due to the expansion / contraction operation of the shock absorber 4 is compensated by the reservoir formed between the cylinder 2 and the outer cylinder.

  The shock absorber 4 according to the present embodiment is a single rod type in which the rod 3 extends only to one side of the piston 11, but may be a double rod type in which the rod 3 extends to both the piston 11.

  Further, as shown in FIG. 1, a wheel side bracket 15 is provided at the lower end in the drawing, which is the end of the rod 3 opposite to the cylinder, which can connect the rod 3 to the wheel side of the vehicle. Specifically, a screw groove (not shown) is formed at the lower end of the rod 3 in the drawing, and the wheel-side bracket 15 is screwed and attached to the screw groove.

  As described above, the cylinder 2 is connected to the vehicle body via the vehicle-side bracket 14, the rod 3 is connected to the wheel side via the wheel-side bracket 15, and the shock absorber 4 is inverted between the vehicle body and the wheels. Interposed in the state. However, the cylinder 2 side of the shock absorber 4 may be connected to the wheel, and the rod 3 side may be connected to the vehicle body, and the shock absorber 4 may be erected between the vehicle body and the wheel.

  A lock nut 16 is screwed into the upper part of the wheel-side bracket 15 of the rod 3 in FIG. 1 to form a double nut structure together with the wheel-side bracket 15 to prevent the wheel-side bracket 15 from being loosened with respect to the rod 3. ing.

  Further, the cushion rubber 5 having an annular shape and made of rubber or the like and having elasticity is attached directly above the lock nut 16 in FIG. The cushion rubber 5 abuts against the stopper 9 and elastically deforms when the shock absorber 4 is most contracted, and reduces the shock when the shock absorber 4 is most contracted.

  The wheel-side bracket 15 has a lower spring support 15a that supports the lower end of the coil spring S in FIG. On the other hand, an upper spring support 17 for supporting the upper end of the coil spring S in the figure is provided on the outer periphery of the upper end in FIG. As described above, the coil spring S is interposed between the upper spring support 17 and the lower spring support 15a and is disposed on the outer periphery of the shock absorber 4, and constantly urges the shock absorber 4 in the extending direction. It functions as a suspension spring that elastically supports the vehicle body.

  In the present embodiment, the wheel-side bracket 15 has the lower-side spring receiver 15a, but the lower-side spring receiver 15a may be separate from the wheel-side bracket 15. However, providing the lower spring receiver 15a on the wheel side bracket 15 is advantageous in that the number of parts can be reduced.

  The coil spring S is formed in a spiral shape by winding a wire having a circular cross section. If one turn of the wire constituting the coil spring S is a coil portion, a plurality of coil springs S extending in the axial direction are formed. It is composed of coil units 20, 30, and 40. Further, the coil spring S is a so-called multi-stage coil spring in which the interval between the coil portions 20, 30, and 40, that is, the pitch differs depending on the portion of the coil spring S.

  At the upper end in FIG. 1 which is the end of the coil spring S on the cylinder side, the inner diameter is gradually increased toward the lower side in FIG. 1 which is the rod side, and the pitch of each coil part 40 is small. A closely wound portion S3 is formed.

  In the center of the coil spring S, a coarsely wound portion S2 having a large pitch between the coil portions 30 is formed. The coarsely wound portion S2 is connected to the lower side of the conical densely wound portion S3 in FIG. 1 in the axial direction, and is arranged in series with the conically densely wound portion S3.

  Further, a densely wound portion S1 having a smaller pitch than the coarsely wound portion S2 is formed at a lower end portion of the coil spring S in FIG. The densely wound portion S1 is axially continued to the lower side in FIG. 1 of the roughly wound portion S2. That is, the coil spring S is provided with the conical densely wound portion S3, the coarsely wound portion S2, and the closely wound portion S1 in order from the top.

  The densely wound portion S1 has a regulating portion 21 facing the cushion rubber 5, and the regulating portion 21 regulates the diameter of the cushion rubber 5 crushed when the shock absorber 4 is most contracted.

  Each coil portion 20 of the close-wound portion S1 has a surface 22 formed on the inner peripheral side by being cut off along the axial direction. Therefore, each surface 22 is arranged on the same cylindrical surface.

  Specifically, while the cross section of the wire rod of the coarsely wound portion S2 is circular, the cross section of the wire rod constituting the densely wound portion S1 has an inner periphery as shown in FIGS. 2 (a) and 2 (b). It has a semicircular shape with a straight surface 22 on the side.

  Then, as shown in FIG. 2B, since these surfaces 22 are arranged on the same cylindrical surface, each surface 22 is on the same circumference when viewed in the axial direction when the tightly wound portion S1 is in close contact. As a result, no spiral dent is formed between the adjacent coil portions 20. Therefore, the inner peripheral surface of the tightly wound portion S1 at the time of close contact is a cylindrical surface having no irregularities, with the surfaces 22 of the coil portions 20 being continuous in the axial direction. Therefore, even when the cushion rubber 5 crushed at the time of the most contraction of the shock absorber 4 comes into contact with the inner peripheral surface of the regulating portion 21, the cushion rubber 5 does not need to be damaged.

  Next, a method for manufacturing the coil spring S according to the present embodiment will be described. 3 and 4, the inner circumference of the densely wound portion S1 'of the coil spring S' which is formed in a spiral shape by winding a wire having a circular cross section and which has a circular cross section is shown in FIGS. 4 is processed so as to be cut off in the axial direction at a center diameter C which is the diameter of the center of the wire of the densely wound portion S1 'indicated by a broken line in FIG. 4, and as shown by a solid line in FIG. The aforementioned surface 22 is formed on the inner peripheral side.

  In the present invention, the method of forming the surface 22 on the inner periphery of the coil portion 20 of the close-wound portion S1 is not particularly limited, and the surface 22 may be formed by, for example, cutting or grinding. Alternatively, the wire material of the closely wound portion S1 may be formed into a shape having the surface 22 in advance.

  In the present embodiment, the surface 22 is provided on the entire inner periphery of the coil portion 20 of the densely wound portion S1, but the surface 22 is restricted at least to the cushion rubber 5 of the densely wound portion S1. It may be provided on the inner periphery of the coil section 20 of the section 21.

  In the present embodiment, the inner diameter of the densely wound portion S1 is set to be equal to the center diameter C of the densely wound portion S1 ′, but the inner diameter of the closely wound portion S1 is larger than the central diameter C. May be done.

  When the inner diameter of the close-wound portion S1 is larger than the center diameter C of the close-wound portion S1 ', the surface 22 of each coil portion 20 is flush, and the inner peripheral surface of the close-wound portion S1 in a close contact state has no irregularities. Since it has a cylindrical surface, a spiral depression cannot be formed between adjacent coil portions 20.

  However, if the inner diameter of the tightly wound portion S1 is increased, the radial thickness of the wire constituting the densely wound portion S1 is correspondingly reduced, and the strength of the coil spring S may be reduced. Therefore, considering the balance with the strength of the coil spring S, it is preferable that the inner diameter of the tightly wound portion S1 including the regulating portion 21 is set to be equal to the center diameter C.

  Next, the operation of the shock absorber 1 according to the present embodiment will be described. When the shock absorber 4 is in the extended state, the coil spring S is also extended, and as shown in FIG. 2A, the coil units 20 forming the densely wound portion S1 are separated from each other.

  However, since the pitch of the densely wound portion S1 is set to be smaller than that of the coarsely wound portion S2, when the coil spring S is compressed due to the contraction of the shock absorber 4, the coiled portion S1 becomes smaller than the coil portion 30 that constitutes the coarsely wound portion S2. The coil portions 20 constituting the close wound portion S1 come into contact with each other first.

  Further, since the pitch of the densely wound portion S1 is set so that the cushion rubber 5 comes into close contact with the regulating portion 21 before being crushed, when the cushion rubber 5 is crushed, the pitch shown in FIG. As shown in ()), the expansion of the cushion rubber 5 is restricted by the restricting portion 21 of the densely wound portion S1. Thereby, the magnitude of the reaction force generated by the cushion rubber 5 at the time of the most contraction of the shock absorber 4 is controlled by the magnitude of the inner diameter of the regulating portion 21.

  When the cushion rubber 5 comes into contact with the inner peripheral surface of the regulating portion 21, there is no gap between the coil portions 20 of the regulating portion 21 because the tightly wound portion S1 is already in close contact with the cushion rubber 5. The cushion rubber 5 is not damaged.

  Further, as described above, when the tightly wound portion S1 is in close contact with the tightly wound portion S1 including the regulating portion 21, no irregularities can be formed on the inner peripheral surface of the tightly wound portion S1. Even when pressed with strong force, the cushion rubber 5 is unlikely to deteriorate. Therefore, the durability of the cushion rubber 5 is improved.

  As described above, the coil spring S of the shock absorbing device 1 according to the present embodiment is a densely wound portion having the coarsely wound portion S2 and the regulating portion 21 having a smaller pitch than the coarsely wound portion S2 and facing the cushion rubber 5. The restricting portion 21 has a surface 22 which can be cut off along the axial direction on the inner peripheral side. When the tightly wound portion S <b> 1 is in close contact, the respective surfaces 22, which are the inner peripheral surfaces of the respective coil portions 20 of the regulating portion 21, are made flush.

  According to this configuration, when the close-wound portion S1 is in close contact, no spiral dent is formed between the adjacent coil portions 20, and the regulating portion 21 has a cylindrical shape with no unevenness on the inner peripheral surface. For this reason, even when the cushion rubber 5 is crushed at the time of the most contraction of the shock absorber 4 and the cushion rubber 5 is pressed against the inner peripheral surface of the regulating portion 21 with a strong force, the cushion rubber 5 is hardly deteriorated. Therefore, the durability of the cushion rubber 5 is improved.

  Further, the coil spring S according to the present embodiment is formed by spirally winding a wire having a circular cross section, but is formed by spirally winding a rectangular pillar-shaped wire having a rectangular cross section. Is also good.

  When the coil spring S is formed by spirally winding a quadrangular pillar-shaped wire, the coil portions 20 of the densely wound portion S1 are displaced in the radial direction and come into contact with each other at the time of close contact, and a step is generated between the coil portions 20. In some cases, unevenness may be formed on the inner peripheral surface of the regulating portion 21 due to the step.

  Even in such a case, if the inner peripheral side of the restricting portion 21 is cut off in the axial direction so that the surfaces 22 of the coil portion 20 are flush with each other when the densely wound portion S1 is in close contact, the restricting portion may be formed. Since the inner periphery of 21 can be made cylindrical without irregularities on the inner peripheral surface when the tightly wound portion S1 is in close contact, deterioration of the cushion rubber 5 can be suppressed.

  Further, as described above, the respective surfaces 22 provided on the inner peripheral side of the coil portion 20 of the regulating portion 21 according to the present embodiment correspond to the inner peripheral side of the densely wound portion S1 'of the coil spring S' before processing. By being cut off along the axial direction at the center diameter C or more, it is formed so as to be flush with the close contact state, but as shown in FIG. It may be cut off in the axial direction.

  In this case, as shown in FIG. 5, the depth D1 of the dent formed on the inner peripheral side between the coil portions 20 of the regulating portion 21 when the densely wound portion S1 is in close contact with the coarsely wound portion indicated by a broken line in FIG. When the portion S2 is in close contact, the depth is less than the depth D2 of the depression formed on the inner peripheral side between the coil portions 30 of the rough winding portion S2. Therefore, the unevenness formed on the inner peripheral surface of the regulating portion 21 at the time of close contact of the tightly wound portion S1 becomes smaller than before, so that the deterioration of the cushion rubber 5 pressed against the regulating portion 21 can be suppressed more than before, and the cushion rubber 5 Durability is improved.

  In addition, as shown in FIG. 6, the curvature of the inner peripheral surface of the coil portion 20 of the regulating portion 21 may be made smaller than the curvature of the inner peripheral surface of the coil portion 30 of the rough winding portion S2. Also in this case, as shown in FIG. 6, the depth D3 of the dent formed on the inner peripheral side between the coil portions 20 of the regulating portion 21 when the tightly wound portion S1 is in close contact with the rough portion indicated by the broken line in FIG. When the wound portion S2 is in close contact, the depth is less than the depth D2 of the depression formed on the inner peripheral side between the coil portions 30 of the coarsely wound portion S2. Therefore, the unevenness formed on the inner peripheral surface of the regulating portion 21 at the time of close contact of the tightly wound portion S1 becomes smaller than before, so that the deterioration of the cushion rubber 5 pressed against the regulating portion 21 can be suppressed more than before, and the cushion rubber 5 Durability is improved.

  Further, in the present embodiment, the tightly wound portion S1 is brought into close contact with the cushion rubber 5 before being crushed and expanded to come into contact with the regulating portion 21. It may be made to do. In this case, since there is no gap between the coil portions 20 constituting the densely wound portion S <b> 1, when the cushion rubber 5 is crushed and comes into contact with the regulating portion 21, the cushion rubber 5 is It is not sandwiched and does not hurt.

  In the present embodiment, the tightly wound portion S1 is in close contact with the cushion rubber 5 before the cushion rubber 5 is crushed and abuts on the restricting portion 21. What is necessary is just to be in the state of being close enough not to be sandwiched between the parts 20.

  In this close state, it is preferable that the interval between the coil portions 20 constituting the densely wound portion S1 is 5 mm or less, but may be larger than 5 mm unless the cushion rubber 5 is sandwiched between the coil portions 20.

  As described above, the preferred embodiments of the present invention have been described in detail. However, it is obvious that modifications, variations, and changes can be made without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 1 ... Buffer device, 2 ... Cylinder, 3 ... Rod, 4 ... Buffer, 5 ... Cushion rubber, C ... Center diameter, S ... Coil spring, 20, 30 , 40 ... coil part, 21 ... regulating part, 22 ... surface, S1: densely wound part, S2 ... coarsely wound part

Claims (5)

A shock absorber having a cylinder and a rod inserted into and out of the cylinder in an axial direction,
A coil spring disposed on the outer periphery of the shock absorber and for urging the shock absorber in the extension direction;
A cushion rubber attached to the outer periphery of the rod to relieve an impact at the time of the most contraction of the shock absorber,
The coil spring has a coarsely wound part and a densely wound part having a regulating part whose pitch is set smaller than the coarsely wound part and faces the cushion rubber,
The shock-absorbing device, wherein the restricting portion has a surface that can cut off an inner peripheral side along an axial direction. A shock absorber having a cylinder and a rod inserted into and out of the cylinder in an axial direction,
A coil spring disposed on the outer periphery of the shock absorber and for urging the shock absorber in the extension direction;
A cushion rubber attached to the outer periphery of the rod to relieve an impact at the time of the most contraction of the shock absorber,
The coil spring has a coarsely wound part and a densely wound part having a regulating part whose pitch is set smaller than the coarsely wound part and faces the cushion rubber,
When the tightly wound portion is in close contact, the depth of the dent formed on the inner peripheral side between the coil portions in the regulating portion is on the inner circumferential side between the coil portions in the coarsely wound portion when the coarsely wound portion is in close contact. A shock absorber characterized by being less than the depth of the depression formed. The shock absorber according to claim 1, wherein the inner peripheral surface of each coil portion of the regulating portion is flush when the close wound portion is in close contact. The shock absorber according to any one of claims 1 to 3, wherein the tightly wound portion is always in close contact. The cushioning device according to any one of claims 1 to 3, wherein the tightly wound portion is in close contact with the cushion rubber before the cushion rubber is crushed and expanded to abut on the regulating portion.

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