JP2010007692A - Dust cover with bound stopper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dust cover with a bound stopper which is capable of enhancing the displacement limiting function of a shock absorber by suppressing the releasing deformation of the bound stopper outward of the direction orthogonal to the axis of the bound stopper during the bound of the shock absorber. <P>SOLUTION: The dust cover 10 has a stopper holding part 14 which is attached to an attachment recess 5 of a holding piece 4 to fit and hold an upper end 12A of a bound stopper 12 to its inside. The stopper holding part comprises an upper wall part 20 which receives an upper surface 12B of the bound stopper, and is kept in a state with an outer circumferential surface thereof being constrained by the attachment recess, and a circumferential wall part 22 to be housed over an outer circumferential surface 12C of an upper end of the bound stopper. A projecting bar 40 and a recessed groove 42 are formed on the upper surface 12B of the bound stopper and a lower surface 20B of the upper wall part 20 of the stopper holding part 14 abutted on the upper surface, respectively, which are fitted to each other to limit the displacement of the bound stopper 12 in the direction Y orthogonal to the axis of the bound stopper. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dust cover that is externally attached to a piston rod of a shock absorber in a suspension mechanism of a vehicle such as an automobile.

  Conventionally, a shock absorber in an automobile suspension mechanism has been provided with a rubber dust cover so as to surround the piston rod in order to prevent dust from entering the sliding portion of the piston rod.

  In this type of dust cover, a bound stopper (also referred to as a bound bumper) made of a foamed elastic body such as urethane foam is provided in the inside in order to limit excessive input when the shock absorber bounces. There is a case where it is accommodated and held (see Patent Documents 1 to 3 below).

In such a conventional dust cover with a bound stopper, the dust cover includes a stopper holding portion having a downward fitting recess, and a thin cylindrical cover portion integrally extending downward from the outer peripheral edge of the lower end in the axial direction. The upper end portion of the bound stopper is fitted and held in the fitting recess of the stopper holding portion.
Japanese Patent Laid-Open No. 06-137357 JP 2000-104781 A JP 2003-056634 A

  In the dust cover with a bound stopper, when the shock absorber is bound, the bound stopper is compressed by the absorber body that is displaced upward, so that the displacement of the shock absorber is buffered by the bound stopper.

  However, with the conventional dust cover with a bound stopper, when an excessive bounce load is input, the bound stopper compressed in the axial direction due to the displacement of the absorber main body is deformed so as to escape outward in the direction perpendicular to the axis, It was found that the original function was impaired. That is, in the above conventional configuration, the outer peripheral surface of the bound stopper is fitted and held by the inner peripheral surface of the fitting recess of the stopper holding portion, and the locking structure for preventing the axial stopper from coming off. Is provided, but there is no structure for limiting displacement in the direction perpendicular to the axis. Therefore, in the conventional configuration, when the bound stopper is compressed in the axial direction, the displacement to the outside in the direction perpendicular to the axis cannot be restricted, and the displacement of the shock absorber is restricted by the escape of the bound stopper to the outside. This function is lost.

  The present invention has been made in view of such problems, and suppresses escape deformation of the bound stopper to the outer side in the direction perpendicular to the axis when the shock absorber bounces, thereby enhancing the displacement limiting function of the shock absorber. An object of the present invention is to provide a dust cover with a bound stopper.

  A dust cover with a bound stopper according to the present invention includes a cylindrical dust cover made of a rubber-like elastic body arranged to surround a piston rod of a shock absorber in a suspension mechanism of a vehicle, and held in the dust cover to And a cylindrical bound stopper made of a foamed elastic body that is externally inserted into the piston rod. The dust cover is mounted in the mounting recess of the holding metal fitting having a downward mounting recess, and has a stopper holding portion having a fitting recess for fitting and holding the upper end portion of the bound stopper, A thin cylindrical cover portion that extends integrally downward from the outer periphery of the lower end of the stopper holding portion in the axial direction and covers the piston rod. Further, the stopper holding portion receives an upper surface of the bound stopper on a lower surface and an upper wall portion fitted and held in a state in which an outer peripheral surface is constrained by an inner peripheral surface of the mounting recess, and an upper end of the bound stopper A peripheral wall portion that is fitted on the outer peripheral surface of the portion and holds the bound stopper, and the fitting recess is formed by the upper wall portion and the peripheral wall portion. And the 1st protruding item | line or 1st ditch | groove extended in the circumferential direction is provided in the upper surface of the said bound stopper, On the lower surface of the upper wall part of the said stopper holding | maintenance part contact | abutted to the upper surface of the said bound stopper, A first concave groove or first convex line extending in the circumferential direction is provided to limit displacement in the direction perpendicular to the axis of the bound stopper by fitting into the convex line or first concave groove.

  According to the present invention, the upper and lower surfaces of the bound stopper and the lower surface of the upper wall portion of the stopper holding portion that is in contact with each other are fitted to each other, thereby limiting the displacement of the bound stopper in the direction perpendicular to the axis. Since one ridge and first groove are provided, when the shock absorber bounces, when the bound stopper is compressed in the axial direction, the bound stopper is prevented from being deformed so as to escape outward in the direction perpendicular to the axis. be able to. In particular, the upper wall portion of the stopper holding portion is fitted and held in a state in which the outer peripheral surface is constrained to the inner peripheral surface of the mounting recess of the holding fitting, that is, the axially perpendicular outer side by the holding fitting. Therefore, by providing the concave / convex fitting portion on the lower surface of the upper wall portion, it is possible to effectively suppress the escape deformation of the bound stopper to the outer side in the direction perpendicular to the axis. Can do. Therefore, the displacement limiting function of the shock absorber can be effectively exhibited.

  Hereinafter, a dust cover according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a dust cover 10 with a bound stopper 12 according to the embodiment, and FIG. 2 is a cross-sectional view showing a state in which the dust cover 10 is incorporated in a suspension mechanism of an automobile.

  The dust cover 10 is a cylindrical rubber member, and is externally inserted into the piston rod 3 so as to surround the outer periphery of the piston rod 3 protruding upward from the cylinder 2 of the shock absorber 1. The dust cover 10 accommodates and holds a bound stopper 12 made of urethane foam that is externally inserted into the piston rod 3. Here, the up-down direction is the axial direction X of the piston rod 3, and is the up-down direction in FIG. In the vehicle mounted state, the axial direction X may be inclined with respect to the vertical line.

  The dust cover 10 is mounted in a state in which it is fitted into a flat-plate-shaped holding metal fitting 4 provided on the tip end side of the piston rod 3. The holding metal fitting 4 is provided with a mounting recess 5 opened downward, and the upper end of the dust cover 10 is fitted into the mounting recess 5 from below. The mounting recess 5 is formed in a tapered surface shape with a gradually decreasing diameter as the inner peripheral surface 5A thereof is upward (ie, the direction toward the bottom of the recess).

  The dust cover 10 holds the upper end portion 12A of the bound stopper 12 and is attached integrally with the stopper holding portion 14 fitted in the mounting recess 5, and extends integrally downward from the outer peripheral edge of the lower end in the axial direction. It consists of a thin cylindrical cover portion 16 that covers the upper end portion of the cylinder 2 together with the piston rod 3.

  The stopper holding portion 14 includes a fitting recess 18 that is opened downward to fit and hold the upper end portion 12 </ b> A of the bound stopper 12. Specifically, as shown in FIGS. 2 and 4, the stopper holding portion 14 is a thick hollow disk-like shape that is fitted and held in a state where the outer peripheral surface 20 </ b> A is constrained by the inner peripheral surface 5 </ b> A of the mounting recess 5. It consists of an upper wall portion 20 and a thick short cylindrical peripheral wall portion 22 that is integrally extended from the outer peripheral edge of the lower end thereof, and the fitting recess 18 is formed inside the upper wall portion 20 and the peripheral wall portion 22. Is formed.

  The upper wall portion 20 of the stopper holding portion 14 is a rubber portion that receives the upper surface 12B of the bound stopper 12 with the lower surface 20B, and constitutes the bottom surface of the fitting recess 18. A through hole 24 having a small diameter enough to allow the piston rod 3 to be inserted is provided in the central portion of the upper wall portion 20. The outer peripheral surface 20 </ b> A of the upper wall portion 20 is formed in a tapered surface shape having a gradually smaller diameter toward the upper side corresponding to the tapered inner peripheral surface 5 </ b> A of the mounting recess 5. It is configured to be fitted.

  The peripheral wall portion 22 of the stopper holding portion 14 is a rubber portion that is fitted onto the outer peripheral surface 12C of the upper end portion of the bound stopper 12 and holds the bound stopper 12, and constitutes the inner peripheral surface of the fitting recess 18. The peripheral wall portion 22 is a portion protruding downward from the mounting recess 5 of the holding metal fitting 4, and the outer peripheral surface 22 </ b> A is not constrained by the mounting recess 5.

  As shown in FIG. 4, the inner peripheral surface 22 </ b> B of the peripheral wall portion 22 has an inner diameter in the axial direction X and the first inner peripheral surface portion 22 </ b> B <b> 1 of the upper half that spreads in a reverse taper shape downward from the lower surface 20 </ b> B of the upper wall portion 20. It consists of the second inner peripheral surface portion 22B2 of the lower half that forms a certain straight cylinder. On the inner peripheral surface 22B of the peripheral wall portion 22, a retaining protrusion 26 (corresponding to the second protrusion) 26 having a rectangular cross section inward in the direction perpendicular to the axis Y is projected over the entire circumference. The retaining ridge 26 is provided on the second inner peripheral surface portion 22B2.

  The cover portion 16 extends downward from the outer peripheral edge at the lower end of the peripheral wall portion 22 and is formed in a thin bellows shape over the entire axial direction X. The lower end of the cover portion 16 is formed as a lower end opening 28 that opens downward.

  The bound stopper 12 held by the stopper holding portion 14 has a thick cylindrical shape having a hollow portion into which the piston rod 3 is inserted, and a plurality of concave portions 30 extending in the circumferential direction are formed on the outer peripheral surface in the axial direction X. In addition to being provided apart from each other, recesses 32 extending in the circumferential direction are also provided on the inner peripheral surface, and these recesses 30 and 32 are alternately arranged in the axial direction X. Reference numeral 34 denotes a resin-made restraining ring provided on the outer peripheral side of the lower end of the bound stopper 12.

The urethane foam as the foamed elastic body forming the bound stopper 12 is not particularly limited, but the closed cell rate (closed cell rate) is preferably 65% or more, and the density is 0.4 to 0. It is preferably 0.8 g / cm ³ . By using such a foamed elastic body, the moisture content of the bound stopper 12 can be lowered, which is advantageous in improving durability.

  As described above, the upper end portion 12A of the bound stopper 12 is a portion that is held by the stopper holding portion 14 of the dust cover 10 and has a larger outer diameter than the lower bound stopper body as shown in FIG. Has been. The outer peripheral surface 12C is provided with a retaining groove 36 (corresponding to a second recessed groove) 36 having a rectangular cross section into which the retaining protrusion 26 of the stopper holding portion 14 is fitted. Specifically, the outer peripheral surface 12C of the upper end portion corresponds to the inner peripheral surface 22B of the peripheral wall portion 22 and has a first outer peripheral surface portion 12C1 that forms a tapered upper half and a lower half portion that forms a straight cylinder. The second outer peripheral surface portion 12C2 is provided with a retaining groove 36 provided in the second outer peripheral surface portion 12C2.

  The upper end portion 12A of the bound stopper 12 is fitted into the fitting recess 18 of the stopper holding portion 14 so that the above-described ridges 26 for retaining and the concave grooves 36 for retaining are fitted as shown in FIG. As a result, as shown in FIG. 1, the upper end 12A of the bound stopper 12 is held in the fitting recess 18 and protrudes downward in the axial direction X in the dust cover 10. Retained. In addition, the code | symbol 38 is an air vent groove which is provided in the circumferential direction in the upper end part 12A of the bound stopper 12, and extends in the axial direction X.

  In the bound stopper 12 fitted and held in this manner, in the present embodiment, the displacement regulating ridge extending in the circumferential direction C (see FIG. 5) on the upper surface (that is, the upper end surface in the axial direction X) 12B. 40 (corresponding to the first ridge) is provided. The displacement regulating ridge 40 has a rectangular cross section as shown in FIG. 6 and is provided over the entire circumference except for the two air vent grooves 38 in the circumferential direction C as shown in FIG.

  Further, as shown in FIG. 4, a displacement regulating groove (corresponding to a first groove) extending in the circumferential direction C is formed on the lower surface 20B of the upper wall portion 20 of the stopper holding portion 14 that contacts the upper surface 12B of the bound stopper 12. 42 is provided. As shown in FIG. 3, the displacement restricting groove 42 is a groove that restricts the displacement of the bound stopper 12 in the direction perpendicular to the axis Y by fitting into the displacement restricting protrusion 40, as shown in FIG. 4. It has a rectangular cross section and is provided over the entire circumference in the circumferential direction C.

  After the dust cover 10 and the bound stopper 12 are formed separately, the bound stopper 12 is inserted from the lower end opening 28 of the dust cover 10 and is fitted into the stopper holding portion 14 at the upper end and held. Let Thereby, the dust cover 10 with the bound stopper 12 is assembled. As shown in FIG. 2, the assembled dust cover 10 with the bound stopper 12 is assembled to the vehicle in a state of being externally attached to the piston rod 3 of the shock absorber 1. Reference numeral 6 denotes a coil spring provided around the shock absorber 1, and its upper end is locked by a spring seat 7 provided on the outer peripheral portion of the holding metal fitting 4.

  According to the dust cover 10 assembled in this way, when the wheel bounces, the upper end surface of the cylinder 2 of the shock absorber 1 comes into contact with the bound stopper 12, and the impact is absorbed by the bound stopper 12 being compressed and deformed. .

  Here, in the present embodiment, the displacement restricting ridge 40 and the displacement restricting groove 42 are provided on the upper surface 12B of the bound stopper 12 and the lower surface 20B of the upper wall portion 20 of the stopper holding portion 14 in contact with the upper surface 12B. Since the displacement in the direction perpendicular to the axis Y of the bound stopper 12 is limited by being fitted to each other, when the bound stopper 12 is compressed in the axial direction X by the bounce, the bound stopper 12 moves outward in the direction perpendicular to the axis. It is possible to prevent deformation to escape to the side Yo (see FIG. 3).

  In this case, in particular, the concave and convex fitting portions 40 and 42 that exert a displacement regulating effect with the bound stopper 12 with respect to the upper wall portion 20 whose outer peripheral surface 20A is restrained by the mounting recess 5 of the holding metal fitting 4 are provided. It is important to provide it. By providing the concave and convex fitting portions 40 and 42 on the lower surface 20B of the upper wall portion 20 which is constrained so that the outer peripheral portion does not move in this rigid body, the bounce stopper 12 escapes to the outer side Yo in the direction perpendicular to the axis. Deformation can be suppressed more effectively. In addition, such an effect of suppressing escape deformation can be achieved with an inexpensive structure. As described above, the displacement limiting function of the shock absorber 1 can be achieved with an extremely effective and inexpensive configuration.

  Further, in the present embodiment, the outer peripheral surface 20A of the upper wall portion 20 of the stopper holding portion 14 and the inner peripheral surface 5A of the mounting recess 5 into which the stopper holding portion 14 is fitted are formed in a tapered surface shape that spreads downward. It is easy to fit the stopper holding portion 14 into the mounting recess 5 and is excellent in workability. In addition, while having such a structure that can be easily fitted, the escape deformation of the bound stopper 12 toward the outer side Yo in the direction perpendicular to the axis can be effectively suppressed by fitting the displacement regulating ridge 40 and the groove 42. Can do.

  FIG. 7 is a cross-sectional view of a dust cover 50 with a bound stopper 12 according to another embodiment, and FIG. 8 is an enlarged view of a main part thereof. In this embodiment, the shape of the outer peripheral surface 20A of the upper wall portion 20 of the stopper holding portion 14 and the shape of the cover portion 16 are different from those of the above embodiment.

  That is, in this example, the outer peripheral surface 20A of the upper wall portion 20 of the stopper holding portion 14 is not tapered as in the above embodiment, but in the circumferential direction so as to be constricted at the boundary with the peripheral wall portion 22. An extending locking groove 52 is provided. As shown in FIG. 8, the mounting recess 5 of the holding metal fitting 4 is formed so that the lower end opening 5 </ b> B has an aperture shape inward in the direction perpendicular to the axis so as to fit into the locking groove 52.

  As shown in FIG. 7, the cover portion 16 includes a bellows portion 16A provided at the upper end portion, and a straight cylindrical portion extending from the lower end of the bellows portion 16A and having a constant outer diameter over the entire length in the axial direction X. 16B. In addition, the lower end opening 28 of the cover portion 16 is provided with an inner flange-shaped portion 54 that protrudes inward in the radial direction in order to enhance the effect of preventing dust from entering.

  Other configurations and operational effects are the same as in the above embodiment. 7 and 8, the portions denoted by the same reference numerals as those in FIGS. 1 to 6 have the same configuration, and the description thereof is omitted.

  In the above embodiment, the displacement restricting ridge 40 is provided on the upper surface 12B of the bound stopper 12, and the displacement restricting groove 42 is provided on the upper wall portion 20 of the stopper holding portion 14. The displacement restricting groove 42 may be provided on the upper surface 12 </ b> B of the stopper 12, and the displacement restricting protrusion 40 may be provided on the upper wall portion 20 of the stopper holding portion 14.

  Further, in the above embodiment, the retaining ridge 26 is provided on the peripheral wall portion 22 of the stopper holding portion 14, and the retaining groove 36 is provided on the outer peripheral surface 12 </ b> C of the upper end portion of the bound stopper 12. Conversely, the retaining groove 14 may be provided on the peripheral wall portion 22 of the stopper holding portion 14, and the retaining protrusion 26 may be provided on the outer peripheral surface 12 </ b> C of the upper end portion of the bound stopper 12.

Sectional drawing of the dust cover with a bound stopper which concerns on one Embodiment of this invention Sectional view showing a state where the dust cover with the bound stopper is incorporated in the suspension mechanism of an automobile Expanded cross-sectional view of the main part of the dust cover with the bound stopper The main part enlarged sectional view of the dust cover Top view of the bounce stopper Sectional view of the bound stopper (cross-sectional view taken along line VI-O-VI in FIG. 5) Sectional drawing of the dust cover with a bound stopper concerning other embodiments The principal part expanded sectional view of the dust cover with a bound stopper of other embodiments

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Shock absorber 3 ... Piston rod 4 ... Holding metal fitting 5 ... Mounting recessed part 5A ... Inner peripheral surface 10, 50 ... Dust cover 12 ... Bound stopper, 12A ... Upper end part, 12B ... Upper surface, 12C ... Upper end outer peripheral surface 14 ... Stopper holding part 16 ... Cover part 18 ... Fitting recess 20 ... Upper wall part of stopper holding part, 20A ... Outer peripheral surface, 20B ... Lower surface 22 ... Peripheral wall part of stopper holding part, 22B ... Inner peripheral surface 26 ... For retaining Projection (second projection)
36 ... Recessed groove (second recessed groove)
40 ... Displacement regulating ridge (first ridge)
42 ... Displacement regulating groove (first groove)
C ... Circumferential direction X ... Axial direction (vertical direction)
Y ... Axis perpendicular direction

Claims (4)

A cylindrical dust cover made of a rubber-like elastic body arranged so as to surround a piston rod of a shock absorber in a suspension mechanism of a vehicle, and a foamed elastic body held in the dust cover and extrapolated to the piston rod With a cylindrical bounce stopper,
The dust cover is mounted in the mounting recess of the holding metal fitting having a downward mounting recess, and has a stopper holding portion having a fitting recess for fitting and holding the upper end portion of the bound stopper, A thin cylindrical cover portion extending integrally from the lower peripheral edge of the lower end of the stopper holding portion in the axial direction and covering the piston rod;
The stopper holding portion receives an upper surface of the bound stopper on the lower surface and an upper wall portion fitted and held in a state in which an outer peripheral surface is constrained by an inner peripheral surface of the mounting recess, and an outer periphery of an upper end portion of the bound stopper A peripheral wall portion that is externally fitted to a surface and holds the bound stopper, and the fitting recess is formed by the upper wall portion and the peripheral wall portion,
A first ridge or first groove extending in the circumferential direction is provided on the upper surface of the bound stopper, and the first ridge is formed on the lower surface of the upper wall portion of the stopper holding portion that contacts the upper surface of the bound stopper. Or, the first groove or the first ridge extending in the circumferential direction to limit the displacement in the direction perpendicular to the axis of the bound stopper by fitting in the first groove is provided,
A dust cover with a bound stopper.   A second groove or second ridge extending in the circumferential direction is provided on the outer peripheral surface of the upper end portion of the bound stopper, and the second groove or second ridge is formed on the inner peripheral surface of the peripheral wall portion of the stopper holding portion. 2. The bounce according to claim 1, wherein a second protrusion or a second groove extending in the circumferential direction for holding the upper end portion of the bounce stopper in the fitting recess by being fitted is provided. Dust cover with stopper.   The outer peripheral surface of the upper wall portion of the stopper holding portion is formed in a tapered surface shape having a gradually smaller diameter as it extends upward, and is configured to be fitted into the mounting recess having a tapered surface-like inner peripheral surface with a gradually decreasing diameter as it is upward. The dust cover with a bound stopper according to claim 1 or 2.   The said 1st protruding item | line is provided in the upper surface of the said bound stopper, The said 1st ditch | groove was provided in the lower surface of the upper wall part of the said stopper holding part, The any one of Claims 1-3 characterized by the above-mentioned. A dust cover with a bound stopper as described in 1.

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