JP2006170386A - Bound stopper for suspension device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foamed polyurethane bound stopper for a suspension device, having no unpleasant abnormal sounds due to friction against a spring seat during stopper operation. <P>SOLUTION: The foamed polyurethane bound stopper 46 elastically abuts on a cylinder during bound to restrict the excessive contractive displacement of a shock absorber. Between a large-diameter fitting portion 60 at the upper end and an annular constriction portion 48 for giving axial compressive deformation capability thereto on the outer peripheral face of an insertion portion 80 which is in the condition of being inserted into a recessed fitting portion 44 of the spring seat 42 under the condition of compressive deformation during the bound of a vehicle, a diameter shrinking guide portion 82 is provided in the form of an approximately inverted taper with its outer diameter gradually smaller toward the upper side for guiding diameter shrinking deformation with the compressive deformation. An annular gap is formed in at least the insertion portion 80 between an inner peripheral face 72 of a center hole 47 and the piston rod to provide for diameter shrinking deformation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cylindrical polyurethane polyurethane bound stopper used in a vehicle suspension apparatus including a shock absorber and a coil spring as constituent elements, and more particularly to a characteristic feature of technical means for preventing abnormal noise.

  Conventionally, in a suspension device for a vehicle that includes a shock absorber and a coil spring as constituent elements, a bound stopper that abuts against a shock absorber cylinder when the vehicle bounces and restricts excessive contraction displacement of the shock absorber has been used. Yes.

For example, Patent Document 1 below discloses this type of bound stopper.
These bound stoppers are made of rubber and foamed polyurethane. Especially, the latter foamed polyurethane bound stopper has higher compressive deformability than the rubber-made bound stopper. It has the feature that the contact can be softened.

The bound stopper has a cylindrical shape as a whole, and an annular deep constriction portion is formed in a plurality of locations in the normal axial direction, that is, in the height direction, in order to enhance the compressive deformability with respect to the entire bound stopper.
And this bound stopper has a shock absorber piston rod inserted through its center hole, and a large diameter fitting part on the upper end usually has a bracket provided on a strut mount that elastically connects the piston rod to the vehicle body It is fitted and assembled so as to be fitted into the concave cup-shaped concave fitting portion.

  Here, the strut mount bracket is generally subjected to cleaning and chemical conversion coating treatment as a surface treatment, and even when the bound stopper compresses and deforms when the vehicle bounces and the bound stopper rubs against the bracket, there is a problem. Such a large noise is unlikely to occur.

On the other hand, in recent years, a reverse seat-like concave fitting part is provided in a spring seat as a spring receiver that receives the upper end of the coil spring, and the large-diameter fitting part of the upper end part of the bound stopper is placed in the inner state. It is considered to mate and assemble.
This spring seat is an important safety part in vehicles, and because of its rust prevention requirements, the surface is coated with a cation, and the surface is a smooth surface. When compressed and deformed during operation, there is a problem that the spring seat, particularly the inner surface of the inverted cup-shaped concave fitting portion, is rubbed, and there is a problem that abnormal noise consisting of stick-slip noise is easily generated there. Arise.
Specifically, the outer peripheral surface of the portion (insertion portion) below the large-diameter fitting portion of the bound stopper that is inserted into the concave fitting portion of the spring seat under the compression deformation state at the time of bouncing Causes bulging deformation outward in the radial direction, and rubs against the inner peripheral surface of the concave fitting portion, resulting in a stick-slip sound that is an unpleasant noise due to the rub.

Japanese Patent Laid-Open No. 8-42624

  In view of the above circumstances, the present invention provides a polyurethane polyurethane bound stopper for a suspension device that can prevent the generation of unpleasant noise caused by rubbing against a spring seat during the stopper action. It was made as a purpose.

  Thus, the first aspect of the present invention is used in a vehicle suspension apparatus including a shock absorber and a coil spring as constituent elements, and has a cylindrical shape as a whole, and the piston rod of the shock absorber is inserted into the center hole. In addition, the large-diameter fitting portion of the upper end portion is fitted and assembled in a state of being fitted into an inverted cup-shaped concave fitting portion formed on a spring seat that receives the upper end of the coil spring, and when the vehicle is bound, A foamed polyurethane bound stopper that elastically contacts the shock absorber cylinder and restricts excessive contraction displacement of the shock absorber, and has a large-diameter fitting portion at the upper end and an axial compressive deformation of the bound stopper. A portion between the annular constriction directly below to give a function and the compression deformation state when the vehicle bounces On the outer peripheral surface of the insertion portion that is inserted into the concave fitting portion of the sheet, the diameter-reducing guide portion that induces the diameter-reducing deformation accompanying the compression deformation, having a substantially reverse tapered shape with the outer diameter gradually decreasing toward the upper side. And an annular gap for deformation reduction is formed between the inner peripheral surface of the central hole and the piston rod at least in the insertion portion.

  According to a second aspect of the present invention, in the first aspect, the constricted portion has a radial depth of 3 to 10 mm, and the minimum diameter portion and the maximum diameter portion at the lower end of the substantially reverse tapered diameter reduction guiding portion. The outer diameter difference is 0.2 to 3.0.

  According to a third aspect of the present invention, in any one of the first and second aspects, the inner circumferential surface of the center hole is formed over the entire height to form an annular gap with the piston rod.

  According to a fourth aspect of the present invention, in the third aspect, the suspension device is of a type in which the piston rod rotates relative to the spring seat around the axis of the piston rod.

  A fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, the spring sheet is provided with a cation coating on the surface thereof to have a smooth surface.

Effects and effects of the invention

As described above, the present invention provides a substantially reverse taper-shaped diameter reduction guiding portion on the outer peripheral surface of the insertion portion that is inserted into the recessed fitting portion of the spring seat under the compression deformation state of the bound stopper, and at least the In the insertion portion, an annular gap for diameter reduction deformation is formed between the inner peripheral surface of the center hole and the piston rod.
In the case of the bound stopper of the present invention, when the bound stopper compresses and deforms when the stopper is operated, the insertion portion that is inserted into the recessed fitting portion of the spring seat by the action of the diameter reduction guiding portion, particularly the minimum diameter portion is on the center hole side. The diameter of the insertion portion is reduced and the outer peripheral surface of the insertion portion is prevented from bulging and deforming radially outward.

  As a result, even when the bound stopper is compressed and deformed when the stopper is operated, the outer peripheral surface of the insertion portion does not rub against the inner peripheral surface of the concave fitting portion of the spring seat, thereby causing uncomfortable due to the rub. Occurrence of abnormal noise is well prevented.

In the present invention, since an annular gap for reducing diameter deformation is formed between the inner peripheral surface of the center hole and the piston rod at least in the insertion portion, the diameter reduction is induced when the bound stopper is compressed and deformed. The part can exhibit its original function well.
Conventionally, the inner peripheral surface of the center hole of the bound stopper is fitted in contact with the piston rod, and in this case, even if the reduced diameter guiding portion as described above is provided, the bound stopper is compressed. At the time of deformation, the reduced diameter guiding portion cannot be favorably deformed in the reduced diameter direction.
However, in the present invention, since the above-mentioned annular gap is formed between the piston rod, the reduced diameter guiding portion, particularly the minimum diameter portion, can be reduced in diameter toward the center hole.

  In the present invention, with respect to the radial depth of 3-10 mm of the constricted portion for imparting deformability in the compression direction to the entire bound stopper, the minimum diameter portion and the maximum of the lower end in the above substantially reverse tapered diameter reduction guiding portion. It is preferable that the outer diameter difference with the diameter portion is in the range of 0.2 to 3.0 (claim 2).

  Further, the center hole of the bound stopper can have an inner peripheral surface extending over the entire height to form an annular gap with the piston rod.

  The third aspect of the present invention is particularly suitable as a bound stopper for a suspension device in which the piston rod rotates relative to the spring seat around the axis of the piston rod (claim 4).

  When the inner peripheral surface of the center hole forms an annular gap with the piston rod over the entire height, when this is applied to the suspension device of claim 4, the rotating piston rod On the other hand, the inner peripheral surface of the bound stopper is rubbed, and it is possible to satisfactorily prevent the generation of abnormal noise due to the rub.

  Further, as is apparent from the above description, the present invention is particularly suitable when applied to a case where the spring sheet is provided with a cationic coating on the surface and has a smooth surface (Claim 5).

Next, embodiments of the present invention will be described in detail with reference to the drawings.
In FIG. 1, reference numeral 10 denotes a vehicle suspension device, here, a shock absorber which is a main element of a strut type suspension device, 12 is a cylinder, and 14 is a piston rod protruding upward from the cylinder 12.
Here, the piston rod 14 is elastically coupled to the vehicle body panel 18 via the bearing 15 and the strut mount 16 so as to be rotatable about its axis.

On the other hand, the lower end portion of the cylinder 12 is fixed to a steering knuckle (not shown).
Therefore, the lower end portion of the cylinder 12 is rotated integrally with the wheel around a line connecting the ball joint for connecting the steering knuckle and the lower arm and the upper end portion of the piston rod, specifically the center of the bearing 15, during steering. Move position.
That is, the shock absorber 10 has its upper end portion fixed to the position of the piston rod 14 and its lower end portion rotates integrally with the wheel around the rotation center of the wheel during steering to change its position.

The strut mount 16 is vibration-insulated between the piston rod 14 and the vehicle body panel 18, and has a tapered outer metal fitting 20, a corresponding substantially tapered inner metal fitting 22, and a rubber elastic body 24 connecting them. And have.
Here, the rubber elastic body 24 is integrally vulcanized and bonded to the outer metal fitting 20 and the inner metal fitting 22.
In the strut mount 16, the outer metal fitting 20 and the inner metal fitting 22 are provided embedded in the rubber elastic body 24.
The strut mount 16 is a boltless type that is not fastened to the vehicle body panel 18 with bolts, and is fitted into the recess 26 formed in the vehicle body panel 18 upward from below and assembled to the vehicle body panel 18. ing.

  Reference numeral 28 denotes a rebound stopper, which includes a stopper fitting 30 and a rubber stopper portion 32 which is integrally vulcanized and bonded thereto. In the stopper fitting 30, an upper end portion of the piston rod 14 is provided by nuts 34-1 and 34-2. It is fastened and fixed to the male screw.

The bearing 15 has an inner ring (upper race ring) 36, an outer ring (lower race ring) 38, and a rolling ball 40 between them. The inner ring 36 is fixed to the piston rod 14 and integrated therewith. Further, the outer ring 38 is fixed to the spring seat 42 so as to rotate integrally therewith.
That is, in this embodiment, the piston rod 14 and the spring seat 42 are rotatable relative to each other independently of each other.
Here, the spring seat 42 is provided as a spring receiver for receiving the upper end of a coil spring (not shown) interposed on the outer peripheral side of the shock absorber 10 and has a concave fitting portion 44 there. 46 is fitted and held.
Here, the metal spring seat 42 is subjected to cationic coating for rust prevention, and the surface thereof is smooth and smooth.

  The bound stopper 46 has its lower end 52 brought into contact with the upper surface of the cylinder 12 when the vehicle bounces, and is elastically deformed by compression, thereby restricting excessive contraction displacement of the shock absorber 10. Here, the bound stopper 46 is polyurethane foam. It is made of.

The bound stopper 46 has a cylindrical shape as a whole and has a center hole 47, and the piston rod 14 is inserted through the center hole 47.
On the outer peripheral surface of the bound stopper 46, constricted portions 48 and 50 for imparting compressive deformability to the bound stopper 46 are formed in an annular shape.
Here, as shown in FIG. 3, the upper constricted portion 48 has a constricted depth α within a range of 3 to 10 mm.
The lower constricted portion 50 also has a constricted depth substantially equal.

The lower part of the lower constricted part 50 is a lower end part 52 that abuts against the cylinder 12 via the cap 53 and compresses and elastically deforms at the initial stage of the stopper action, and the inner periphery of the lower end part 52 On the side, another constricted portion 54 opposite to the constricted portion 50 is formed in an annular shape.
Here, the cap 53 is plated, and the surface thereof is smooth and smooth.
The lower end 52 also has an outer diameter that is smaller than the portion above the constricted portion 50, and the entire lower end 52 is easily deformed.

  In the bound stopper 46, an annular recess 56 is formed on the outer peripheral surface of an intermediate portion between the upper constricted portion 48 and the lower constricted portion 50, and a restraining ring 58 made of a rigid resin is fitted therein. ing.

As shown in FIG. 3, the upper end portion of the bound stopper 46 is a large-diameter fitting portion 60, and the large-diameter fitting portion 60 is located below the concave fitting portion 44 of the spring seat 42. From above and is held in an internally fitted state.
Specifically, here, the outer peripheral surface 62 and the upper end surface 64 of the large-diameter fitting portion 60 contact the inner peripheral surface and the upper bottom surface of the concave fitting portion 44, respectively. 60 is fitted.

  As shown in FIGS. 2 and 3, the fitting portion 60 allows air to flow between the inside and the outside of the bound stopper 46 at the time of the stopper action at the time of bouncing and further at the time of releasing the stopper action. A plurality of air passages 66 (three in this case) are provided in the radial direction.

In this embodiment, the inner diameter of the bound stopper 46, that is, the diameter of the center hole 47 is larger than the outer diameter of the piston rod 14, and the piston rod covers the entire length from the upper end to the lower end in a normal state. 14 to form an annular gap.
Also the central hole 47 is the angle theta ₁ tapered whose diameter increases as it travels toward the bottom from the top as shown in FIG.
However, the center hole 47 may have a shape that continuously increases in diameter from the upper end to the lower end, or may have a shape that gradually increases in diameter. Furthermore, it may not be a strict taper shape, but may be curved in its entirety or partially in the axial direction.

The bound stopper 46 also has a fine unevenness on the entire outer peripheral surface 62 and upper end surface 64 of the fitting portion 60, and further on the lower end surface 65 and outer peripheral surface 70 of the lower end portion 52, and further on the inner peripheral surface 72 of the center hole 47. The embossed surface 68 is a group.
The embossed surface 68 is a surface molded with an embossed surface formed in advance in a corresponding portion of the mold when the polyurethane bound stopper 46 is molded with a mold, It consists of a number of grain protrusions 74 and grain valleys 76 between them.
In the present embodiment, the depth of the embossing, that is, the height of the embossing protrusion 74 or the depth of the embossed valley portion 76 is set within a range of 250 ± 50 μm. Further, the number of embossed protrusions 74 per 1 cm ² is set to a high density of 5 or more.

The bound stopper 46 of the present embodiment has its lower end 52 mainly brought into contact with the upper surface of the cylinder 12 of the shock absorber 10, more specifically, the upper surface of the cap 53, and compressively elastically deforms when the vehicle bounces. Restricts the displacement in the direction of contraction.
At that time, the lower end 52 not only contacts the cylinder 12 with the lower end surface 65 via the cap 53, but also the outer peripheral surface 70 also contacts the upper surface of the cylinder 12 via the cap 53 due to axial compression deformation. At that time, the lower end surface 65 and the outer peripheral surface 70 of the lower end portion 52 are rubbed relative to the cylinder 12.

Also in the fitting portion 60, the outer peripheral surface 62 and the upper end surface 64 rub against the inner peripheral surface and the upper bottom surface of the concave fitting portion 44 of the spring seat 42 with compression deformation.
Further, particularly during steering, the piston rod 14 relatively moves in a twisting direction as shown in FIG. 4 with respect to the bound stopper 46, and at this time or further by the input of a load, the spring seat 42 is moved together with the upper end of the coil spring. When the relative rotation occurs, the piston rod 14 may contact the inner peripheral surface 72 of the center hole 47 of the bound stopper 46, or may rotate relatively while contacting. At this time, the inner peripheral surface 72 of the bound stopper 46 is rubbed against the piston rod 14.

  Here, in the present embodiment, since all the surfaces that cause such rubbing are the textured surface 68, it is possible to satisfactorily prevent the generation of abnormal noise due to such rubbing.

In the present embodiment, the portion between the large-diameter fitting portion 60 at the upper end of the bound stopper 46 and the upper annular constricted portion 48, that is, the constricted portion 48 immediately below the fitting portion 60, is at the time of the stopper action. When the bound stopper 46 is compressed and elastically deformed, as shown in FIG. 5, it is a portion that is almost entirely inserted into the recessed fitting portion 44 of the spring seat 42. As shown in FIG. The entire outer peripheral surface 80 is a reduced diameter guiding portion 82 having a reverse taper shape (angle θ ₂ ) in which the outer diameter gradually becomes smaller as it advances upward.

  Here, the maximum diameter portion 84 at the lower end of the reverse tapered shape has an outer diameter equal to the outer diameter of the intermediate portion 86 between the constricted portions 48 and 50. Therefore, the minimum diameter portion 88 at the upper end of the reduced diameter guiding portion 82 is smaller than the outer diameter of the intermediate portion 86. However, the outer diameter of the minimum diameter portion 88 is larger than the outer diameter of the constricted portion 48.

Here, the outer diameter of the minimum diameter portion 88 is φ52 mm with respect to the outer diameter φ53 mm of the intermediate portion 86. That is, the outer diameter of the minimum diameter portion 88 in the reduced diameter guiding portion 82 is 1 mm smaller than the outer diameter of the maximum diameter portion 84.
The outer diameter of the constricted portion 48 is φ40 mm. Therefore, the constricted depth α is specifically 6.5 mm here.

  When the bound stopper 46 is compressed and deformed at the time of the stopper action, the diameter reduction guiding portion 82 causes the insertion portion 80, particularly the minimum diameter portion 88, to be formed by an annular gap between the piston rod 14 and the inner peripheral surface 72 of the center hole 47. In this embodiment, as a result of this, in the present embodiment, when the bound stopper 46 is compressed and deformed, the insertion portion 80 is effectively suppressed from bulging and deforming outward in the radial direction.

FIG. 5 shows this. As shown in FIG. 5, the insertion portion 80 does not bulge and deform in the radially outward direction under the compression deformation state of the bound stopper 46. The insertion portion 80 is prevented from rubbing against the inner peripheral surface of the concave fitting portion 44 of the spring seat 42 by the deformation.
6 shows, as a comparative example, the case where such a diameter reduction guiding portion is not formed in the insertion portion 80A, and the diameter of the reverse tapered shape is reduced on the outer peripheral surface of the insertion portion 80A of the bound stopper 46A in this comparison example. The guiding portion is not formed, and the outer peripheral surface is an axial straight surface.

Further, as shown in FIG. 6A, the bound stopper 46 </ b> A has an upper inner peripheral surface 72 fitted in contact with the piston rod 14.
As a result, in the case of the bound stopper 46A shown in FIG. 6 of this comparative example, when the bound stopper 46A is compressed and elastically deformed in the axial direction when the stopper is actuated, the insertion portion 80A bulges radially outward, and the spring seat There arises a problem that the inner peripheral surface of the concave fitting portion 44 of 42 is brought into contact with and rubbed on the basis of the contact to generate an abnormal noise due to the rub.

  However, in this embodiment, as shown in FIG. 5, the insertion portion 80 does not bulge and deform, and therefore does not rub against the inner peripheral surface of the concave fitting portion 44 of the spring seat 42. No unpleasant noise.

  In the present embodiment, since an annular gap for diameter reduction deformation is formed between the inner peripheral surface 72 of the center hole 47 and the piston rod 14, the diameter reduction induction portion 82 is provided at the time of compression deformation of the bound stopper 46. The original function can be demonstrated well.

  Further, in this embodiment, since the inner peripheral surface 72 of the center hole 47 forms an annular gap with the piston rod 14 over the entire height, smooth rotational movement of the piston rod 14 is ensured. At the same time, the rubbing of the inner peripheral surface 72 of the bound stopper 46 is suppressed during the rotation.

Although the embodiment of the present invention has been described in detail above, this is merely an example.
For example, the diameter-reduction guide portion on the outer peripheral surface of the insertion portion may not have a strict reverse taper shape but may have a substantially tapered shape. Specifically, it may not be a strict reverse taper shape as long as the diameter becomes smaller as it progresses upward.
In addition, this invention can be comprised in the form which added the various change in the range which does not deviate from the meaning.

It is a figure which shows the bound stopper of one Embodiment of this invention in the mounting state to a suspension apparatus. It is a perspective view of the bound stopper in FIG. It is the (A) longitudinal cross-sectional view, (B) top view, and (C) CC sectional view in the same bound stopper. It is action | operation explanatory drawing of the same bound stopper. FIG. 5 is an operation explanatory view different from FIG. 4 of the bound stopper. It is a comparative example figure of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Shock absorber 12 Cylinder 14 Piston rod 42 Spring seat 44 Concave fitting part 46 Bound stopper 47 Center hole 48, 50, 54 Constriction part 60 Fitting part 72 Inner peripheral surface 80 Insertion part 82 Reduction diameter induction part 84 Maximum diameter part 88 Minimum diameter part

Claims (5)

Used as a suspension device for a vehicle having a shock absorber and a coil spring as constituent elements. As a whole, the cylinder is formed into a cylindrical hole, and a piston rod of the shock absorber is inserted into the center hole. The joint portion is fitted and assembled so as to be fitted in a reverse cup-shaped concave fitting portion formed on a spring seat that receives the upper end of the coil spring, and elastically contacts the shock absorber cylinder when the vehicle bounces. A polyurethane polyurethane bound stopper for restricting excessive contraction displacement of the shock absorber, and a large diameter fitting portion at the upper end portion and an annular constriction directly below for imparting compressive deformability in the axial direction to the bound stopper. Between the spring seat and the concave fitting portion of the spring seat under the compression deformation state when the vehicle bounces. Provided on the outer peripheral surface of the insertion portion that is in the inserted state is a substantially reverse tapered shape whose outer diameter gradually becomes smaller toward the upper side, and a reduced diameter induction portion that induces the reduced diameter deformation accompanying the compression deformation, and at least the insertion A bounding stopper for a suspension device, wherein an annular gap for the reduced diameter deformation is formed between an inner peripheral surface of the center hole and the piston rod in a portion.   In Claim 1, the radial direction depth of the said constriction part is 3-10 mm, and the outer diameter difference of the minimum diameter part in the said substantially reverse taper diameter reduction induction | guidance | derivation part and the maximum diameter part of a lower end is 0.2. A bound stopper for a suspension device, characterized by being -3.0.   The bound stopper for a suspension device according to any one of claims 1 and 2, wherein an annular clearance is formed between the inner peripheral surface of the center hole and the piston rod over the entire height.   4. The bound stopper for a suspension device according to claim 3, wherein the suspension device is of a type in which the piston rod rotates relative to the spring seat around the axis of the piston rod.   The bound stopper for a suspension device according to any one of claims 1 to 4, wherein the spring seat has a surface coated with a cation and is smooth.

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