JP2011064255A - Dust boot and shock absorber using dust boot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce weight by thinning a wall and to prevent deformation. <P>SOLUTION: A piston rod side mounting part 50B and a housing side mounting part 52 are formed at the opposite ends in a vertical direction of a dust boot 12. A straight part 58 is formed between a bumper rubber part 50 and a bellows part 56 in the dust boot 12 and, in the straight part 58, a plurality of ribs 60 are formed in a ring shape in the circumferential direction. The straight part 58 is reinforced by the ribs 60 and an intermediate portion in the longitudinal direction of the straight part 58 is prevented from having cross sectional deformation in the inner direction when the dust boot 12 contracts. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a dust boot and a shock absorber using the dust boot.

Conventionally, as a dust boot used for a shock absorber, one having a bellows portion having a bellows shape so as to expand and contract in accordance with expansion and contraction of the shock absorber is known.
For example, Patent Documents 1 to 3 disclose dust boots having a bellows portion.

Japanese Utility Model Publication No. 60-41651 JP 2009-56852 A JP 2003-322192 A

  However, in the dust boots as in Patent Documents 1 to 3, when the thickness of the dust boot is reduced in the entire area of the dust boot for the purpose of reducing the weight, the cylinder that is not in the bellows shape when the shock absorber contracts. There is a risk of the shape portion being deformed by a compressive load.

  The present invention has been made to solve the above problems, and an object thereof is to obtain a dust boot that can be reduced in weight by being thinned and can be prevented from being deformed, and a shock absorber using the dust boot.

  The dust boot of the first aspect of the present invention includes a first side mounting portion formed at one end portion in the cylindrical longitudinal direction and a second mounting portion formed at the other end portion in the cylindrical longitudinal direction. And a bellows part formed in a cylindrical longitudinal intermediate part, having a bellows shape along the longitudinal direction and capable of expanding and contracting in the longitudinal direction, and formed in a cylindrical longitudinal intermediate part and extending along the longitudinal direction A straight portion having a cylindrical shape; and a reinforcing portion that is formed at a middle portion in the longitudinal direction of the straight portion and prevents cross-sectional deformation of the straight portion.

  Weight reduction can be achieved by thinning the entire dust boot. In this case, the portion that does not need to be a bellows-shaped bellows portion in the longitudinal direction of the dust boot is a cylindrical straight portion, so that the portion that does not need to be a bellows portion is lighter than a configuration that does not have a straight portion. Can be planned. On the other hand, in the straight part that is easily deformed in cross section when contracted due to thinning, it is difficult to deform against a compressive load by forming a reinforcing part for preventing cross-sectional deformation in the longitudinal intermediate part of the straight part. Can be structured.

  According to a second aspect of the present invention, in the dust boot according to the first aspect, the reinforcing portion is a rib protruding to the outer peripheral side of the straight portion.

  Since the reinforcing portion for preventing the deformation of the cross section formed at the intermediate portion in the longitudinal direction of the straight portion is a rib protruding to the outer peripheral side of the straight portion, a structure that is difficult to deform can be obtained with a simple configuration.

  According to a third aspect of the present invention, in the dust boot of the second aspect, the rib is formed in a ring shape along the circumferential direction of the straight portion.

  The rib that is formed in the middle part in the longitudinal direction of the straight part and protrudes toward the outer periphery of the straight part is formed in a ring shape along the circumferential direction of the straight part. Can be prevented.

  According to a fourth aspect of the present invention, in the dust boot according to the third aspect, a plurality of the ribs are formed at predetermined intervals along the longitudinal direction of the straight portion.

  Since a plurality of ribs are formed at predetermined intervals along the longitudinal direction of the straight portion, the plurality of ribs can prevent deformation in a wide range in the longitudinal direction of the straight portion.

  According to a fifth aspect of the present invention, in the dust boot according to any one of the first to fourth aspects, the load per unit length of the straight portion in a standard load load state during use is that of the bellows portion. Less than the load per unit length.

  The load per unit length of the straight part under standard load conditions during use is smaller than the load per unit length of the bellows part. For this reason, compared to the case where the load per unit length of the straight part in the standard load state during use is greater than or equal to the load per unit length of the bellows part, As a result, it becomes difficult for the straight portion to be deformed, and the weight can be further reduced accordingly.

  A shock absorber according to a sixth aspect of the invention includes the dust boot according to any one of the first to fifth aspects, a piston rod and a chamber portion that are movable relative to each other along the axial direction. A first attachment portion of the dust boot is attached to the piston rod, and a second side attachment portion of the dust boot is attached to the chamber portion.

  The first attachment portion of the dust boot according to any one of claims 1 to 5 is attached to the piston rod of the shock absorber, and the second attachment portion of the dust boot is attached to the chamber portion of the shock absorber. ing. For this reason, by thinning the dust boot attached to the shock absorber, the dust boot can be reduced in weight and deformation of the dust boot can be prevented.

  As described above, the dust boot of the present invention according to claim 1 has an excellent effect that it can be reduced in weight and prevented from being deformed by being thinned.

  The dust boot of the present invention according to claim 2 has an excellent effect that it can be made into a structure that is not easily deformed with a simple configuration.

  The dust boot of the present invention according to claim 3 has an excellent effect that deformation can be prevented in the entire circumferential direction of the straight portion.

  The dust boot of the present invention according to claim 4 has an excellent effect of preventing deformation in a wide range in the longitudinal direction of the straight portion.

  The dust boot of the present invention according to claim 5 can be further reduced in weight.

  The shock absorber of the present invention according to claim 6 has an excellent effect that the dust boot can be prevented from being deformed and the weight can be reduced by reducing the thickness.

It is a longitudinal section showing a dust boot concerning one embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view taken along a line 2-2 in FIG. It is a perspective view which shows the dust boot which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows the shock absorber of the motor vehicle provided with the dust boot which concerns on one Embodiment of this invention.

An embodiment of the present invention will be described below with reference to the drawings.
(Composition of shock absorber)
A shock absorber using the dust boot of this embodiment will be described with reference to FIG. FIG. 4 is a cross-sectional view of the automobile suspension as seen from the front side of the vehicle body. In addition, an arrow UP in the figure indicates the upper part of the automobile body.

  As shown in FIG. 4, the automobile suspension 10 according to the present embodiment is a strut suspension. The dust boot 12 of this embodiment is mounted so as to cover the piston rod 16 of the shock absorber 14 and the upper end portion 18A of the cylindrical housing 18 as a chamber portion. Accordingly, the sliding surface of the piston rod 16 and the sealing surface between the piston rod 16 and the housing 18 are not always exposed by the dust boot 12, and dust, water, sand, etc. enter the dust boot 12. Can be prevented.

  A bumper rubber portion (bump stopper portion) 50 is integrally and continuously formed (as one component) at the upper end portion of the dust boot 12. The bumper rubber portion 50 of the dust boot 12 is attached to the upper end portion (tip portion) 16A of the piston rod 16 protruding from the housing 18 of the shock absorber 14.

  A lower insulator rubber 22 is disposed on the upper end side of the bumper rubber portion 50 of the dust boot 12 via a metal plate 20. In addition, an upper spring seat 26 having a concave portion 26 </ b> A at the center is disposed above the lower insulator rubber 22 via a lower retainer 24, and the concave portion 26 </ b> A of the upper spring seat 26 is in contact with the lower retainer 24.

  An upper insulator rubber 30 is disposed inside the recess 26 </ b> A of the upper spring seat 26. An upper retainer 32 is sandwiched between the recess 26 </ b> A of the upper spring seat 26 and the upper insulator rubber 30.

  The height of the upper insulator rubber 30 is set to a height that does not protrude from the recess 26 </ b> A of the upper spring seat 26. Each of the metal plate 20, the lower insulator rubber 22, the lower retainer 24, the upper spring seat 26, the upper retainer 32, and the portions of the upper insulator rubber 30 that are coaxial with the piston rod 16 is formed with a through hole, Bolt portions 17 erected integrally with the piston rod 16 are inserted through these through holes. That is, the piston rod 16 is attached to the vehicle body (not shown) at the bolt portion 17 via the upper support portion including the metal plate 20, the lower insulator rubber 22, the lower retainer 24, the upper spring seat 26, the upper retainer 32, and the upper insulator rubber 30. It is installed.

  An upper seat rubber 34 is attached to the lower surface of the outer peripheral edge portion 26B bent outward in the horizontal direction from the upper end of the concave portion 26A of the upper spring seat 26, and the upper seat rubber 34 has a ring shape. A ring-shaped lower spring seat 38 is attached to the outer periphery of the housing 18 of the shock absorber 14, and a coil spring 40 is disposed between the lower spring seat 38 and the upper seat rubber 34.

  The lower part of the housing 18 of the shock absorber 14 is connected to a wheel (not shown), and a flange 18B is formed at the upper end of the housing 18. The outer diameter of the flange 18B is larger than the outer diameter of the general portion of the housing 18, and when the piston rod 16 contracts greatly, the flange 18B comes into contact with the lower surface 50A of the bumper rubber portion 50 of the dust boot 12, The movement of the piston rod 16 is limited.

(Dust boot configuration)
The dust boot of this embodiment is demonstrated according to FIGS.
FIG. 1 is a longitudinal sectional view of the dust boot of this embodiment. 2 is an enlarged cross-sectional view taken along the line 2-2 of FIG. 1, and FIG. 3 is a perspective view of the dust boot of the present embodiment.

As shown in FIG. 3, the dust boot 12 is made of rubber and has a cylindrical shape with a circular cross section.
As shown in FIG. 1, the bumper rubber part 50 formed in the upper part of the dust boot 12 has a cylindrical shape with an inner diameter R1. Further, the upper end of the bumper rubber portion 50 is connected to a piston rod side mounting portion 50B as a first mounting portion having an outer diameter R2 attached to the upper end portion (tip portion) 16A of the piston rod 16 of the shock absorber 14 shown in FIG. It has become.

On the other hand, the outer diameter R3 of the lower end 50C of the bumper rubber part 50 is larger than the outer diameter R2 of the piston rod side mounting part 50B (R2 <R3). Further, at the middle portion in the vertical direction of the bumper rubber portion 50, a thick portion 50E having an outer diameter R5 larger than the outer diameter R4 of the general portion 50D in the middle portion in the vertical direction is predetermined along the longitudinal direction (vertical direction). A plurality of locations (two locations in this embodiment) are formed at intervals of.
The lower end portion of the dust boot 12 is a housing side mounting portion 52 as a second mounting portion, and the housing side mounting portion 52 is attached to the outer peripheral portion of the upper end portion 18A of the housing 18 as shown in FIG. Yes.

  As shown in FIG. 1, the housing-side mounting portion 52 of the dust boot 12 has a cylindrical shape with an inner diameter R6, and the lower end 52A has a bowl shape with an outer diameter R7. Further, the outer diameter R8 of the upper end 52B of the housing side mounting portion 52 is larger than the outer diameter R7 of the lower end 52A (R7 <R8), and the outer diameter R9 of the intermediate portion 52C in the vertical direction of the housing side mounting portion 52 is It is smaller than the outer diameter R7 of the lower end 52A (R9 <R7).

  A bellows portion 56 having a bellows shape along the longitudinal direction is formed at a portion continuing to the housing side mounting portion 52 in the middle portion of the dust boot 12 in the longitudinal direction (vertical direction). It can be stretched. On the other hand, a straight portion 58 is formed at a portion continuing to the bumper rubber portion 50 in the longitudinal intermediate portion of the dust boot 12, and the upper end of the bellows portion 56 and the lower end of the straight portion 58 are connected.

  That is, a straight portion 58 is formed between the bumper rubber portion 50 and the bellows portion 56 in the dust boot 12. In the present embodiment, the length L1 of the bellows portion 56 is shorter than the length L2 of the straight portion 58.

  In the bellows portion 56, a large-diameter portion 56A having an outer diameter R8 and a small-diameter portion 56B having an outer diameter R10 (R10 <R8) are alternately formed. The thickness M1 of the bellows portion 56 is generally equal to that of the bumper rubber portion 50. The thickness M2 of the portion 50C is equal to or substantially equal to the thickness M3 of the intermediate portion 52C in the vertical direction of the housing side mounting portion 52. The inner diameter R11 of the small diameter portion 56B of the bellows portion 56 is larger than the inner diameter R6 of the housing side mounting portion 52 (R11> R6).

  On the other hand, the outer diameter R12 of the straight portion 58 is equal to or substantially equal to the outer diameter R3 of the lower end 50C of the bumper rubber portion 50. Further, the inner diameter R13 of the straight portion 58 is equal to or substantially equal to the inner diameter R11 of the small diameter portion 56B of the bellows portion 56, and the thickness of the straight portion 58 is M4. Further, a rib 60 as a reinforcing portion is formed in a ring shape along the circumferential direction of the straight portion 58 at the intermediate portion in the longitudinal direction of the straight portion 58, and the rib 60 has a trapezoidal cross section on the outer peripheral side of the straight portion 58. Protruding. In addition, the cross-sectional shape seen from the circumferential direction of the rib 60 is not limited to a trapezoidal shape, and may be other shapes such as a rectangular shape or a semicircular shape.

  More specifically, the portion where the rib 60 of the straight portion 58 is formed is a cylindrical shape having an outer diameter R14 and an inner diameter R13, and the portion where the rib 60 of the straight portion 58 is formed is the height of the rib 60 ( Due to M5-M4), the thickness M5 is thicker than the thickness M4 of the general portion 58A of the straight portion 58 (M5> M4). In addition, a plurality of ribs 60 (two in this embodiment) are formed at predetermined intervals along the longitudinal direction (vertical direction) of the straight portion 58.

  The lower end portion 58B of the straight portion 58 is a thick portion, the outer diameter R15 thereof is equal to or substantially equal to the outer diameter R14 of the rib 60, and the thickness M6 of the lower end portion 58B of the straight portion 58 is The thickness M5 of the portion where the rib 60 is formed is equal to or substantially equal to the thickness M5.

  As shown in FIG. 3, the rib 60 of the straight portion 58 is formed in a ring shape (continuously) along the circumferential direction of the straight portion 58, and the straight portion 58 is reinforced by the rib 60. That is, these ribs 60 cause cross-sectional deformation (buckling) in the inner direction (arrow A direction) as shown by a two-dot chain line in FIGS. 3 and 4 at the longitudinal intermediate portion of the straight portion 58. Can be prevented.

  In the present embodiment, the load F1 per unit length of the straight portion 58 in the standard load state when the dust boot 12 is used is smaller than the load F2 per unit length of the bellows portion 56 (F1 < F2).

  More specifically, in the dust boot 12 of the present embodiment, the length L2 of the straight portion 58, the thickness of the straight portion 58 from the relationship of the length of the coil spring 40, the spring constant, the length L4 of the bumper rubber portion 50, and the like. M5, the number of ribs 60, height (M5-M4), width L3, length L1 of bellows portion 56, and thickness M1 are set appropriately so that the straight load in the standard load load state when dust boot 12 is used The load F1 per unit length of the part 58 is made smaller than the load F2 per unit length of the bellows part 56 (F1 <F2).

  The standard load applied state when the dust boot 12 is used is that the dust boot 12 is used (attached) to the suspension 10 of the present embodiment, the suspension 10 is contracted to the standard position, and a compressive load acts on the dust boot 12. It is in the state.

  For this reason, the cross-sectional deformation (buckling) of the straight part 58 in the standard load load state at the time of use of the dust boot 12 can be prevented more effectively.

(Function and effect)
The dust boot 12 of this embodiment can reduce the weight of the rubber by reducing the thickness and reducing the thickness in the entire area. At this time, a portion that does not need to be the bellows-shaped bellows portion 56 in the longitudinal direction of the dust boot 12 is made the cylindrical straight portion 58 as much as possible, whereby the straight portion 58 has a bellows shape (bellows shape). It is possible to reduce the weight as compared with a configuration in which a portion that does not need to be a portion is not a straight portion. Further, since the amount of rubber used is reduced, the cost can be reduced.

  On the other hand, when the weight is reduced by reducing the thickness, the straight portion 58 of the dust boot 12 is shown by a two-dot chain line in FIGS. 3 and 4 when the dust boot 12 is contracted compared to the bellows portion 56. The cross-sectional deformation (buckling) in the inner direction (arrow A direction) is likely to occur.

  For this reason, in this embodiment, as shown in FIG. 2, a plurality of ribs 60 are formed in a ring shape protruding on the outer peripheral side of the straight portion 58 along the circumferential direction in the straight portion 58 of the dust boot 12. The straight portion 58 is reinforced by the rib 60. As a result, these ribs 60 cause cross-sectional deformation (buckling) in the inner direction (arrow A direction) as shown by the two-dot chain line in FIGS. 3 and 4 at the longitudinal intermediate portion of the straight portion 58. Can be prevented.

  Therefore, the dust boot 12 of the present embodiment can be reduced in weight by being thinned and can be prevented from being deformed.

Further, in this embodiment, since the reinforcing portion for preventing the cross-sectional deformation of the straight portion 58 is the rib 60 protruding to the outer peripheral side of the straight portion 58, a structure that is difficult to deform with a simple configuration can be achieved. .
In the present embodiment, the intermediate portion in the longitudinal direction of the straight portion 58 undergoes cross-sectional deformation (buckling) in the inner direction (arrow A direction) as shown by a two-dot chain line in FIG. Can be prevented.
Further, in the present embodiment, the rib 60 is formed in a ring shape along the circumferential direction. For this reason, the rib 60 can prevent deformation in the entire circumferential direction of the straight portion 58.

  In the present embodiment, a plurality of ribs 60 (two places) are formed at predetermined intervals along the longitudinal direction of the straight portion 58. For this reason, these ribs 60 can prevent cross-sectional deformation (buckling) in a wide range in the longitudinal direction of the straight portion 58.

  Further, in the present embodiment, the length L2 of the straight portion 58, the thickness M5, the number of ribs 60, and the height from the relationship of the length L4 of the coil spring 40, the spring constant, the length L4 of the bumper rubber portion 50, and the like. (M5-M4), the width L3, the length L1 of the bellows portion 56, and the wall thickness M1 are set so that the load F1 per unit length of the straight portion 58 in the standard load state when the dust boot 12 is used. However, it is smaller than the load F2 per unit length of the bellows part 56 (F1 <F2). For this reason, the straight portion 58 is not easily deformed (buckled) in cross section with respect to a standard load applied state to the dust boot 12 in use, and the dust boot 12 can be further reduced in weight accordingly.

  Further, in the shock absorber 14 of the present embodiment, the dust boot 12 of the present embodiment is used, so that the dust boot 12 can be prevented from being deformed and thinned to reduce the weight. Further, it is possible to prevent the intermediate portion in the longitudinal direction of the straight portion 58 from being deformed in cross section (buckling) in the inner direction (arrow A direction) as shown by a two-dot chain line in FIG. .

[Other Embodiments]
Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art. For example, in the dust boot 10 of the above-described embodiment, the bumper rubber portion 50 is integrally formed continuously at the upper end portion. Instead, the dust boot 10 and the bumper rubber portion are separated from each other. It is good also as the structure which carried out.

  Moreover, the dust boot 10 of the said embodiment is applicable also to shock absorbers other than the said embodiment, and elastic members other than a shock absorber.

  Although not shown in the drawings, the invention according to claim 1 has a configuration other than the rib 60 in which the reinforcing portion for preventing the cross-sectional deformation of the straight portion 58 of the dust boot 10 protrudes from the outer peripheral side of the straight portion 58. For example, the structure used as other reinforcement parts, such as the thick part protruded to the inner peripheral side of the straight part 58, is also contained.

  Although not shown in the drawings, the invention according to claim 2 has a configuration in which the rib 60 is formed in a ring shape along the circumferential direction of the straight portion 58, for example, the rib 60 has the straight portion 58. A configuration formed in a spiral shape along the circumferential direction is also included.

  Although not shown in the drawings, the invention according to claim 3 has a configuration other than the plurality of ribs 60 formed at predetermined intervals along the longitudinal direction of the straight portion 58, for example, the rib 60 is a straight portion. A configuration in which only one is formed along the longitudinal direction of 58 is also included.

DESCRIPTION OF SYMBOLS 10 Suspension 12 Dust boot 14 Shock absorber 16 Shock absorber piston rod 18 Shock absorber housing (chamber part)
50 Bumper rubber part of dust boot 50B Piston rod side mounting part (first mounting part)
52 Housing side mounting part (second mounting part)
56 Bellows part of dust boot 58 Straight part of dust boot 60 Rib (reinforcement part)

Claims (6)

A first attachment portion formed at one end of the cylindrical longitudinal direction;
A second attachment portion formed at the other end in the cylindrical longitudinal direction;
A bellows portion formed in a cylindrical longitudinal intermediate portion, having a bellows shape along the longitudinal direction and capable of extending and contracting in the longitudinal direction;
A straight portion formed in a cylindrical middle portion in the longitudinal direction and having a cylindrical shape along the longitudinal direction;
Formed in the longitudinal intermediate portion of the straight portion, and a reinforcing portion for preventing cross-sectional deformation of the straight portion;
Having dust boots.   The dust boot according to claim 1, wherein the reinforcing portion is a rib projecting to the outer peripheral side of the straight portion.   The dust boot according to claim 2, wherein the rib is formed in a ring shape along a circumferential direction of the straight portion.   The dust boot according to claim 3, wherein a plurality of the ribs are formed at predetermined intervals along the longitudinal direction of the straight portion.   The dust boot according to any one of claims 1 to 4, wherein a load per unit length of the straight portion is smaller than a load per unit length of the bellows portion in a standard load load state during use. The dust boot according to any one of claims 1 to 5,
A piston rod and a chamber part that are movable relative to each other along the axial direction;
Have
A shock absorber in which a first attachment portion of the dust boot is attached to the piston rod, and a second attachment portion of the dust boot is attached to the chamber portion.

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