JP5085485B2 - Dust cover assembly structure - Google Patents

Description

  The present invention relates to an assembly structure of a resin dust cover that covers a piston rod of a shock absorber in a suspension mechanism from the outside.

2. Description of the Related Art Conventionally, in a vehicle, a piston rod of a shock absorber in a suspension mechanism is covered from the outside with a resin cylindrical dust cover to protect the sliding portion of the piston rod from the outside.
Conventionally, this dust cover is usually formed by blow molding, and when the dust cover is attached to the vehicle, the dust cover is attached to a rigid attachment that attaches and fixes the shock absorber piston rod to the vehicle body via a cushion rubber. 2. Description of the Related Art Conventionally, blow molding and joining and integration are performed and a dust cover is held by such a fixture.
For example, Patent Document 1 below discloses an example of attaching such a dust cover to a vehicle.

FIG. 7 shows a specific example thereof.
In the figure, 200 is a shock absorber, 202 is a cylinder, and 204 is a piston rod protruding from the cylinder 202.
The piston rod 204 is elastically attached and fixed to a vehicle body 214 via a metal support fitting (rigid attachment tool) 206 via an upper support 212 having a lower cushion rubber 208 and an upper cushion rubber 210. ing.

The mounting bracket 206 includes a mounting plate portion 216 and a cylindrical peripheral wall portion 218 at the outer periphery thereof. The lower cushion rubber 208 of the upper support 212 and the upper clamp 212 are connected to the upper support 212 by the mounting plate portion 216 and the upper clamping bracket 220. The piston rod 204 is elastically connected to the body 214 in a state where the cushion rubber 210 is sandwiched and elastically pressed against the body 214.
Reference numeral 222 denotes a bound stopper that elastically contacts the cylinder 202 when the piston rod 204 contracts to prevent excessive contraction of the piston rod 204, and an upper end portion thereof is held in the fitting fitting 206.

224 is a resin-made cylindrical dust cover that covers the piston rod 204 from the outside, and an assembly portion 226 on the upper end side thereof is joined and assembled to the outer peripheral surface of the peripheral wall portion 218 of the mounting bracket 206. Is held in.
The dust cover 224 made of this blow molded product is assembled to the mounting bracket 206 as follows.

  That is, the end of the cylindrical resin parison of the dust cover 224 extruded from the extrusion device is extrapolated to the mounting bracket 206 set in the state where the blow mold that opens and closes in the direction perpendicular to the axis is opened. The blow molding die is clamped, and the end of the parison externally attached to the mounting bracket 206 at the end molding portion of the blow molding die is pressed inward in the direction perpendicular to the axis (inward in the radial direction). The inner circumference and the outer circumference are generally reduced in diameter so that the mounting portion 226 is formed into a molding shape along the outer peripheral surface of the peripheral wall portion 218 of the mounting bracket 206, and at the same time, the mounting portion 226 is formed around the entire circumference. It is assembled in an integrally joined state to the mounting bracket 206 so as to be in close contact with the outer peripheral surface of the spanning peripheral wall portion 218.

  Furthermore, compressed gas is blown into the inside of the parison, the portion excluding the above-mentioned end portion of the parison is pressed against the inner peripheral molding surface of the blow molding die, blow molding is performed, and the dust cover 224 is molded at the same time. Assume that the metal fitting 206 is assembled.

In the example of FIG. 7, the mounting bracket 206 is formed by bending a single metal plate. However, the mounting bracket 206 is formed as a separate cup-shaped upper bracket 206- as shown in FIG. 1 and a lower metal fitting 206-2 having an inverted cup shape are also welded to each other.
Thus, the point which comprises the attachment metal fitting 206 by the upper metal fitting 206-1 and the lower metal fitting 206-2 is disclosed by the following patent document 2. FIG.

However, in order to blow-mold the dust cover 224 and at the same time to be integrally joined to the mounting bracket 206, a high level of technology is required and the price becomes expensive.
In order to jointly integrate and assemble the dust cover 224 to the mounting bracket 206 at the same time as blow molding, the mounting bracket 206 must be set as an insert in the blow mold when the dust cover 224 is molded, and the dust cover 224 must be blow molded. Therefore, a lot of labor and time are required for forming the dust cover 224, which increases the manufacturing cost. In addition, the productivity also decreases.

  As a countermeasure, it is conceivable that the dust cover 224 is formed of a resin injection molded product, and the dust cover 224 is formed by itself and then assembled to the mounting bracket 206 in a subsequent process.

When the dust cover 224 is formed by injection molding, it is not necessary to set the mounting bracket 206 as an insert in the molding die at the time of molding, and it can be molded in a short cycle time.
However, in this case, the structure of assembling the dust cover 224, which is independently molded by injection, to the mounting bracket 206 becomes a problem.

  When assembling the dust cover 224, which is independently formed, to the mounting bracket 206, the assembly must be easy and easy to assemble. On the other hand, the dust cover 224 is firmly mounted after mounting. Must be able to be fixed to 206.

  In addition, the dust cover 224 must not be detached from the mounting bracket 206 or fall off when vibration during driving of the vehicle or any external force is applied to the dust cover 224 after assembly.

In addition, there exists what was disclosed by the following patent document 3 as a prior art with respect to this invention, and the point which comprises a dust cover by the injection molding product of resin is disclosed there.
In this case, however, the dust cover is assembled to the bound stopper and held there, and does not solve the problem of the present invention.

  Patent Document 4 below discloses a structure in which a dust cover molded independently is assembled to the holding member, but this structure is basically different from the present invention in the structure of assembling the dust cover. This is different from the present invention.

Japanese Patent Laid-Open No. 2004-100088 JP 2002-130359 A JP 2007-198512 A JP 2003-194129 A

  The present invention is based on the above circumstances, and a resin dust cover molded separately can be easily assembled to a rigid fixture that attaches a shock absorber piston rod to a vehicle body via a cushion rubber. The object is to provide a dust cover assembly structure that can be firmly fixed after assembly and can be provided at low cost.

Thus, in the first aspect, the piston rod of the shock absorber in the suspension mechanism of the vehicle is fixed to the cylindrical peripheral wall portion of the rigid fixture for fixing the piston rod of the shock absorber to the body of the vehicle via the cushion rubber. A dust cover assembly structure in which a cylindrical dust cover made of resin having a cylindrical shape at least at the upper end side is assembled in an externally fitted state at the upper end side, and the lower end of the peripheral wall portion of the fixture has a lower end An engagement hole is provided at an upper position than the lower end in an independent closed shape that is discontinuous with the lower end, and is provided at a plurality of three or more locations in the circumferential direction, while the dust cover is formed of a resin injection molded product. In addition, the protrusions for engagement protruding radially inwardly on the inner peripheral surface on the upper end side by the injection molding are integrally formed at a plurality of locations in the circumferential direction corresponding to the holes. The dust cover has an inner diameter smaller than an outer diameter of the fitted portion on the lower end side of the peripheral wall portion of the fixture at a lower portion of the protrusion, and has a predetermined diameter with respect to the fitted portion. A fitting fixing portion that elastically fits in an outer fitting state at a tightening margin is provided, the dust cover is extrapolated upward to the peripheral wall portion of the fixture through an opening at the upper end, and the projection for engagement is inserted into the fixture. Over the outer peripheral surface of the peripheral wall portion below the hole portion and engage with the hole portion, and the fitting fixing portion is elastically fitted to the fitted portion in an outer fitting state, The dust cover is structured to be assembled to the fixture by the engaging force and the engagement action of the hole and the projection, and the dust cover has a vertical cross-sectional shape that is thicker from the lower end to the upper end side. The fitting fixing part is gradually thicker than the fitting fixing part. Wherein the are no thicker with respect to the lower portion.

  According to a second aspect of the present invention, in the first aspect of the present invention, the dust cover has an inner diameter larger than an outer diameter of the fitted portion in the upper portion of the projection, and the dust cover is passed through the opening. A cylindrical guide portion for extrapolating and guiding when the outer peripheral portion of the fixture is extrapolated upward is provided.

According to a third aspect of the present invention, in any one of the first and second aspects, the engagement hole portion extends vertically from a position above the lower end of the peripheral wall portion of the fixture and moves the protrusion upward. It has a shape having a vertical hole portion to be guided and a lateral hole portion that extends in the circumferential direction at a position above the lower end of the vertical hole portion and that engages the protrusion at the assembly position. A downwardly shaped portion is provided that is downwardly lowered as it moves away from the vertical hole portion in the circumferential direction toward the front end in the direction .

Effects and effects of the invention

  As described above, in the dust cover assembly structure according to the first aspect of the present invention, the engagement hole is provided in the peripheral wall portion of the fixture at an upper position than the lower end thereof, and has an independent closed shape at a plurality of three or more locations in the circumferential direction. On the other hand, the dust cover is formed of a resin injection molded product, and the engaging protrusions protruding radially inwardly on the inner peripheral surface on the upper end side are integrally formed at a plurality of locations corresponding to the holes, Further, the dust cover is provided with a fitting fixing portion that is elastically fitted in an outer fitting state with a predetermined tightening to a fitting portion on a lower end side of the peripheral wall portion of the fitting in a lower portion of the projection, The cover is extrapolated upward to the fixture through the opening at the upper end, and at that time, the engaging projection is moved over the outer peripheral surface of the lower portion from the hole of the peripheral wall portion of the fixture, and is inserted into the hole portion. The fitting fixing part is elastically fitted to the fitted part in the outer fitting state. , Its elastic fitting force, in which no by engaging action between the hole and the protrusion so as to assemble the dust cover to the fixture.

According to such an assembly structure, the dust cover can be easily assembled to the fixture by simply fitting the injection-molded dust cover upward to the peripheral wall portion of the fixture through the opening at the upper end.
After assembly, the dust cover is based on the engagement force between the hole portion of the fixture and the projection of the dust cover, and on the basis of the elastic fitting force between the fitting portion of the fixture and the fitting fixing portion of the dust cover. Can be firmly fixed to the fixture.

According to the first aspect, the dust cover can be easily and inexpensively manufactured by injection molding with high productivity.
Further, since the dust cover is made of an injection molded product, the above-mentioned engaging projection on the inner peripheral side can be easily integrally formed with a thick wall during the injection molding.

  The present invention secures the dust cover to the fixture by engaging the hole on the fixture side with the projection on the dust cover side, and the elasticity between the fitting portion of the fixture and the elastic fitting portion of the dust cover. It is characterized by the fact that it is performed with the fitting force.

  For example, if the dust cover is fixed to the fixture with only the elastic fitting force between the fitted part and the fitting fixing part, the fitting fixing part of the resin cover will become slightly slack and stress over time. When the elastic fitting force is reduced due to relaxation or the like, the dust cover may be detached from the fixture.

  However, in the assembly structure according to the first aspect, the hole portion on the fixture side and the protrusion on the dust cover side are engaged with each other, so that the hole portion is located above the lower end of the fixture. There is a protrusion entering and engaging there, and in order for the dust cover to be detached from the fixture, the projection must get over the outer peripheral surface on the lower end side of the fixture, so that the projection is removed from the hole. Therefore, the assembled state of the dust cover to the fixture can be maintained well.

  In addition, the hole is located on the upper side of the lower end of the fixture, and the fixture is not divided in the circumferential direction (by the hole) at the lower portion thereof, and has a shape connected in the circumferential direction. The rigidity of the fitted part in the fixture can be made high, and the fixing force by fitting between the fitted part and the fitting fixing part on the dust cover side can be made high strength.

Further, in the first aspect, the vertical cross-sectional shape of the dust cover is formed so that the thickness gradually increases from the lower end to the upper end side, and the fitting fixing portion is thicker than the lower portion. It is done.
By doing so, it is possible to effectively increase the rigidity of the fitting and fixing portion that is an assembly portion with respect to the fixture, thereby making the structure for fixing the dust cover to the fixture higher in strength. be able to.

In addition, by reducing the thickness of the lower portion of the fitting fixing portion, the weight of the entire dust cover can be reduced, and the burden on the assembly portion can be reduced.
Moreover, by doing in this way, the mold release property from the shaping | molding die of the dust cover as a molded article at the time of injection molding can be made favorable.
Here, the fitting fixing part can be formed so that the thickness is uniform in the vertical direction and the inner peripheral surface and the outer peripheral surface form a straight shape along the axis of the dust cover.

  In the present invention, the inner diameter of the upper portion of the dust cover is larger than the outer diameter of the fitted portion of the fitting, and the dust cover is directed upward to the peripheral wall portion of the fitting through the upper end opening. When extrapolating, a cylindrical guide portion that provides the extrapolation guide can be provided (claim 2).

Since the guide portion is not elastically fitted to the fixture, the guide portion can be easily fitted to the peripheral wall portion of the fixture.
Thereafter, by the guiding action of the guide portion, the projection reaches the position where it reaches the hole portion over the outer peripheral surface on the lower end side of the fixture, and the fitting fixing portion on the dust cover side is covered with the peripheral wall portion on the fixture side. The dust cover can be easily extrapolated upward with respect to the fixture up to the position where the fitting portion is fitted.

  According to a third aspect of the present invention, the hole for engagement on the fixture side has a shape having a vertical hole for moving and guiding the protrusion on the dust cover upward, and a horizontal hole extending in the circumferential direction, and the horizontal hole. The part is provided with a downwardly-shaped part that is downwardly lowered as it moves away from the vertical hole part in the circumferential direction toward the distal end in the lateral direction.

  In this third aspect, when extrapolating the dust cover upward with respect to the fixture, the projection of the dust cover is first engaged with the lower end of the vertical hole, and then the projection is moved upward along the vertical hole. Thereafter, the protrusion can be moved along the horizontal hole portion by the relative rotation of the dust cover with respect to the fixture, and the protrusion can be engaged with the horizontal hole portion in the vertical direction.

In this case, the length over the outer peripheral surface on the lower end side of the fixture before the protrusion enters the hole can be shortened as much as possible, and the assembly of the dust cover to the fixture is improved. Can do.
On the other hand, by engaging the protrusions in the lateral hole portions, the protrusions can be restrained in the vertical direction, and rattling of the dust cover relative to the fixture can be prevented.

In addition, since this horizontal hole portion is located above the lower end of the vertical hole portion, by engaging the protrusion with this horizontal hole portion, the fitting fixing portion on the dust cover side and the fitting portion on the fixture side The fitting length in the vertical direction can be made long, and the fixing strength of the dust cover to the fixture can be made high.
Further, the lateral hole portion is provided with a lowered shape portion, and the projection can be prevented from moving in the rotational direction along the lateral hole portion by moving and engaging the projection therewith.

After assembly, there is no particular input in the rotational direction for the dust cover while the vehicle is running, but even if there is an input in the rotational direction for the dust cover for any reason, the protrusions are In order to move the lateral hole portion in the circumferential direction to the portion side, the lowered shape portion must be ridden.
However, normally, such a large rotational force is not applied to the dust cover. Therefore, by engaging the protrusion with the hole in the lowered shape portion, it is possible to effectively prevent the protrusion from rotating to the vertical hole. be able to.

It is also conceivable that the vertical hole is extended downward to reach the lower end of the fixture, the hole is opened at the lower end of the fixture, and is formed in a continuous open shape at the lower end.
In such a case, the projection on the dust cover side is easily inserted upward into the hole from the lower end of the fixture through the opening, and the projection is inserted into the horizontal hole by rotating the dust cover, and is inserted into the horizontal hole. It can be made to engage.

However, in this case, if the protrusion located in the horizontal hole reaches the vertical hole due to rotation of the dust cover for some reason, the protrusion is easily detached from the hole through the opening of the vertical hole.
However, in the present invention, since the hole portion is provided at a position above the lower end of the fixture and is provided at the lower end in a discontinuous independent closed shape, such a problem does not occur.
In this case, the front surface of the engaging hole can be an inverted L shape .

Next, embodiments of the present invention will be described in detail with reference to the drawings.
In FIG. 1, 10 is a shock absorber, 12 is a cylinder, and 14 is a piston rod protruding from the cylinder 12.
The piston rod 14 is elastically attached and fixed to the body 18 of the vehicle via an upper support 20 with a fitting (rigid fitting) 16.

  More specifically, the lower cushion rubber 26 and the upper cushion rubber 28 of the upper support 20 are sandwiched between the mounting plate portion 22 and the plate-shaped upper clamping bracket 24 of the mounting bracket 16, and the piston is brought into an elastic pressure contact with the body 18. The rod 14 is elastically connected to the body 18.

  The piston rod 14 has an annular flange 30 protruding outward in the radial direction and a male threaded portion 32 at the tip, and a tightening nut 34 is screwed into the annular flange 30, and the flange 30 and the tightening nut 34. Thus, the mounting plate portion 22 and the upper clamping bracket 24 are sandwiched vertically.

  36 is a bound stopper that elastically contacts the cylinder 12 when the piston rod 14 contracts and restricts excessive contraction of the piston rod 14, and has a cylindrical shape as a whole. The metal fitting 16 is elastically fitted into a holding portion 40 to be described later and held there.

  15 is a dust cover made of resin (here, made of polypropylene resin) that covers the piston rod 14 from the outside, and has a cylindrical shape as a whole. The dust cover 15 is assembled to the mounting bracket 16 at the assembly portion 17 on the upper end side and held there. ing.

  As shown in FIG. 2, the mounting bracket 16 includes an upper bracket 42 that is cup-shaped upward and a lower bracket 44 that is cup-shaped downward, and the upper bracket 42 is connected to the upper support 20. The lower portion of the lower cushion rubber 26 is fitted and held.

  The upper metal fitting 42 has a circular lower bottom portion 46, a cylindrical peripheral wall portion 48 rising upward from the outer peripheral end thereof, and an annular flange portion 50 projecting radially outward from the upper end of the peripheral wall portion 48. As a bottomed cylindrical shape.

On the other hand, the lower metal fitting 44 has a circular upper base portion 52 and a cylindrical peripheral wall portion 54 that falls from the outer peripheral end thereof.
The upper metal fitting 42 and the lower metal fitting 44 are integrated by spot welding at a plurality of locations in the circumferential direction at the lower bottom portion 46 and the upper bottom portion 52 that are overlapped with each other.

Here, the lower bottom portion 46 and the upper bottom portion 52 constitute the mounting plate portion 22 described above, and the peripheral wall portion 48 of the upper bracket 42 and the peripheral wall portion 54 of the lower bracket 44 constitute a peripheral wall portion of the entire mounting bracket 16. Yes.
The mounting plate 22 is provided with an insertion hole 55 for the piston rod 14 at the center thereof.

The peripheral wall portion 54 of the lower metal fitting 44 includes a first holding portion 56 that has a reverse taper shape downward following the upper bottom portion 52, a widened portion 58 that extends in a tapered shape following the first holding portion 56, and A straight cylindrical second holding portion 60 that hangs down downward from the lower end, and the fitting portion 38 of the bound stopper 36 is elastically fitted upward into the first holding portion 56. It is held there.
Here, the straight cylindrical second holding portion 60 has the same inner diameter and outer diameter, and has a straight shape in the axial direction, that is, the vertical direction.

A tapered guide portion 64 is provided on the outer periphery of the lower end.
The guide portion 64 serves as a guide when the dust cover 15 is fitted to the mounting bracket 16.
Here, the guide portion 64 may have a curved shape that is curved in an arc shape or the like.

The straight cylindrical second holding portion 60 in the lower metal fitting 44 is provided with through holes 62 for engagement used for attaching the dust cover 15 at four locations separated by 90 ° in the circumferential direction. .
These four hole portions 62 are all provided at positions above the lower end of the peripheral wall portion 54, and the four hole portions 62 are provided at the same height position.

In the present embodiment, these engaging holes 62 have an inverted L shape as a whole in the front shape.
Specifically, the hole 62 has a lower end positioned above the lower end of the peripheral wall portion 54 and extending vertically from the lower end in the figure upward, and from the upper end of the vertical hole 66 in the circumferential direction. And a lateral hole 68 extending.
The horizontal hole portion 68 is provided with an inclined portion (falling shape portion) 70 having a shape inclined downward as it goes away from the vertical hole portion 66 in the circumferential direction toward the tip.
A protrusion 72 described later on the dust cover 15 is engaged with the hole 62 at the circumferential end of the horizontal hole 68 at the final assembly position.

  In this embodiment, the lower portion of the peripheral wall portion 54 below the circumferential end of the horizontal hole portion 68 forms a fitted portion 69 for fitting the dust cover 15.

In this embodiment, the dust cover 15 made of resin and having a cylindrical shape as a whole is formed of a resin injection molded product, and is formed on the inner surface of the assembly portion 17 on the upper end side as shown in FIG. The engaging protrusions 72 corresponding to the hole 62 on the mounting bracket 16 side protrude radially inward at four circumferential positions corresponding to the hole 62, that is, at four positions spaced by 90 ° in the circumferential direction. It is provided in the state.
Here, each protrusion 72 is formed at the same time as the injection molding of the dust cover 15.

Each projection 72 has a circular front shape, and each inner end surface is a flat surface in the vertical direction, that is, in a direction parallel to the axis of the dust cover 15 in FIG.
The outer peripheral surface of each protrusion 72 is a tapered surface that increases in diameter toward the root side.

As shown in FIG. 3C, these four protrusions 72 are provided at the same height position corresponding to the hole 62, respectively.
In the dust cover 15, the portion immediately below these protrusions 72 has an inner diameter d ₁ (here, d ₁ = φ53.9 mm) over the height h, and the outer diameter d _{0 of the} fitting portion 69 in the mounting bracket 16. (FIG. 2 (B)) (here, d = φ54.2 mm. Therefore, the dimensional difference is 0.3 mm), and it is elastic to the external fitting state with a predetermined tightening margin with respect to the fitting portion 69. The fitting fixing portion 74 is fitted.

On the other hand, the portion located above the protrusion 72 and reaching the upper end of the dust cover 15 has an inner diameter d ₂ than the outer diameter d ₀ of the straight cylindrical second holding portion 60 including the fitted portion 69 (see FIG. 3) is a guide portion 76 having a large diameter.
Here, the inner peripheral surface of the fitting and fixing portion 74 is a flat surface extending with the same diameter in the direction parallel to the axial direction of the dust cover 15 over the height H.
Further, the inner peripheral surface of the portion from the guide portion 76 to the fitting and fixing portion 74 is a tapered surface that connects the inner peripheral surface of the guide portion 76 having a large diameter and the inner peripheral surface of the fitting and fixing portion 74 having a small diameter. It is said that.

In addition, the outer diameter size of the fitting portion 69 in the mounting bracket 16 and the inner diameter size of the fitting fixing portion 74 in the dust cover 15 cause dimensional variations and errors during manufacture of each product.
If a gap is generated between the outer peripheral surface of the fitting portion 69 and the inner peripheral surface of the fitting fixing portion 74 due to the dimensional variation and error, the dust cover 15 cannot be fixed to the mounting bracket 16 satisfactorily.

So here is the minimum in the outer diameter d ₀ of the fitting portion 69 is the tolerance, also even if the inner diameter d ₁ of the fit fixing part 74 is maximum within the tolerance, the outer periphery thereof fitted portion 69 Each dimension and tolerance are set so that no gap is generated between the surface and the inner peripheral surface of the fitting fixing portion 74.

On the other hand, when the inner diameter d ₂ (here d ₂ = φ54.5 mm) of the guide portion 76 becomes smaller than the outer diameter d ₀ of the second holding portion 60 including the fitted portion 69, the dust cover 15. Can not be fitted and attached to the mounting bracket 16 in detail, and the guide portion 76 cannot exhibit the original guide action in detail, and therefore the outer diameter d ₀ of the second holding portion 60 is here. There is a maximum within the tolerance, and in case the inner diameter d ₂ of the guide portion 76 is the minimum within the tolerances also, the inner diameter d ₂ of the guide portion 76 does not become smaller than the outer diameter d ₀ of the second holding portion 60 In other words, the dimensions are set so that the gap between them is zero at the minimum.
The protrusion height of the protrusion 72, that is, its thickness is 1 mm here.

Next, the procedure for assembling the dust cover 15 to the mounting bracket 16 in this embodiment will be described below.
In this embodiment, the dust cover 15 is extrapolated upward to the second holding portion 60 of the mounting bracket 16 through the opening at the upper end, and the assembly portion 17 on the upper end side is assembled to the mounting bracket 16.

  At this time, as shown in FIG. 5 (I) and FIG. 6 (I), by the guide action of the guide portion 76 in the dust cover 15 and the guide action of the guide portion 64 at the outer peripheral portion of the lower end of the mounting bracket 16. The dust cover 15 can be smoothly fitted into the second holding portion 60 of the peripheral wall portion 54 of the mounting bracket 16 through the opening at the upper end thereof, and the dust cover 15 can be pushed upward.

  At that time, the fitting portion 16 and the dust cover 15 are positioned in the radial direction by fitting the guide portion 76 of the dust cover 15 to the second holding portion 60 of the peripheral wall portion 54. The center of the dust cover 15 in the radial direction is well aligned. That is, the radial alignment of the dust cover 15 with respect to the mounting bracket 16 is favorably performed.

  When the upper end of the dust cover 15 is fitted into the second holding part 60 of the mounting bracket 16, if the center position of the mounting bracket 16 and the center position of the dust cover 15 are greatly shifted, the circumferential direction 4 of the dust cover 15 is reduced. Any one of the protrusions 72 provided at the location is greatly hung on the peripheral wall portion 54 of the mounting bracket 16 (the allowance is increased) or the other protrusion 72 is slightly hung, and then each protrusion 72 is attached. When it rides on the outer peripheral surface of the lower end of the metal fitting 16, it becomes a large resistance, and the resistance differs for each projection 72 and becomes unbalanced.

However, in this embodiment, by the guide action of the guide portion 76 provided on the dust cover 15, more specifically, the centering action, each projection 72 is in a state of being hooked on the lower end of the mounting bracket 16 with a substantially equal size and hooking margin. When the dust cover 15 is pushed upward, a resisting force with an equal force is generated for each protrusion 72, and therefore, each protrusion 72 can ride on the outer peripheral surface of the lower end portion of the mounting bracket 16 in a well-balanced manner.
Furthermore, the action of the guide portion 76 can prevent the dust cover 15 from being fitted in an inclined state with respect to the mounting bracket 16.

5 (II) and FIG. 6 (II) show a state in which each protrusion 72 rides on the outer peripheral surface of the lower end of the mounting bracket 16, and in this state, the dust cover 15 faces further upward with respect to the mounting bracket 16. When the projection 72 reaches the lower end of the vertical hole 66 in the hole 62, the projections 72 are fitted into the lower ends of the corresponding vertical holes at the same time.
FIG. 5 (III) and FIG. 6 (III) show the state at this time.

In this embodiment, the dust cover 15 is further pushed upward from here, and each protrusion 72 is moved upward in the vertical hole portion 66.
When the protrusion 72 reaches the upper end of the vertical hole portion 66, the dust cover 15 is rotated relative to the mounting bracket 16 to cause the protrusion 72 to enter the horizontal hole portion 68 in the hole portion 62, and finally the horizontal hole. The protrusion 72 is rotationally moved to the position of the circumferential end of the portion 68.

4 and 5 (IV) show the state at this time.
In this state, the protrusion 72 is restrained in the vertical direction by the horizontal hole portion 68, so that the dust cover 15 is prevented from being displaced in the vertical direction and rattling.
The horizontal hole 68 is provided with the inclined portion 70 as described above, and the projection 72 is finally engaged with the horizontal hole 68 at the lowest position of the inclined portion 70.

  Accordingly, even if a force in the rotational direction is applied to the dust cover 15 after the assembly, the projection 72 must ride on the inclined portion 70 upward at this time. Since it does not act on the cover 15, as a result, the projection 72 is constrained in the left and right rotational directions by the action of the inclined portion 70 in the horizontal hole portion 68, and thus the projection 72 moves to the vertical hole portion 62 after assembly. There is no such thing.

Under the state where the projection 72 is engaged with the tip of the horizontal hole portion 68 in this way, the fitting fixing portion 74 immediately below the projection 72 in the dust cover 15 is predetermined on the outer peripheral surface of the fitting portion 69 in the mounting bracket 16. It will be in the state elastically fitted to the external fitting state at the tightening margin.
That is, the fitting fixing portion 74 is fitted and fixed to the fitting portion 69 so that the outer peripheral surface of the fitting portion 69 is elastically clamped with a predetermined tightening force.

As shown in FIG. 3, the dust cover 15 is gradually thinner at the lower portion than the fitting and fixing portion 74 toward the lower end.
Specifically, the dust cover 15 has a tapered shape in which the inner diameter of the lower portion of the fitting and fixing portion 74 gradually increases toward the lower end.

  In other words, the dust cover 15 is thicker than the lower portion of the fitting and fixing portion 74, and therefore the fitting and fixing portion 74 has a larger rigidity than the other lower portion. Thus, the fixing force due to the fitting between the fitting fixing portion 74 and the fitting portion 69 of the mounting bracket 16 becomes high strength.

As described above, according to the present embodiment, the dust cover 15 can be easily assembled to the mounting bracket 16 simply by fitting the injection-molded dust cover 15 upward to the peripheral wall portion 54 of the mounting bracket 16 through the opening at the upper end. Can do.
After assembly, due to the engagement force between the hole 62 of the mounting bracket 16 and the protrusion 72 of the dust cover 15, the elasticity of the fitted portion 69 of the mounting bracket 16 and the fitting fixing portion 74 of the dust cover 15. Based on the fitting force, the dust cover 15 can be firmly fixed to the mounting bracket 16.

In this embodiment, the dust cover 15 can be manufactured easily and inexpensively by injection molding and with high productivity.
In addition, when the dust cover 15 is injection-molded, the engagement protrusion 72 on the inner peripheral side can be easily and integrally formed at the same time.

In the present embodiment, the dust cover 15 is fixed to the mounting bracket 16 by engaging the hole 62 on the mounting bracket 16 side with the protrusion 72 on the dust cover 15 side, and the fitted portion 69 of the mounting bracket 16. This is performed by an elastic fitting force with the elastic fitting portion 74 of the dust cover 15.
For example, when the dust cover 15 is fixed to the mounting bracket 16 only by the elastic fitting force between the fitted portion 69 and the fitting fixing portion 74, the fitting fixing portion in the resin dust cover 15 is used. There is a possibility that the dust cover 15 may be detached from the mounting bracket 16 when the elastic fitting force is reduced due to the sagging of 74 or stress relaxation over time.

  However, in the mounting structure of the present embodiment, the hole 62 on the mounting bracket 16 side and the projection 72 on the dust cover 15 side are engaged with each other, so that the hole 62 is further than the lower end of the mounting bracket 16. Since the protrusion 72 enters and engages with the upper position and the dust cover 15 is detached from the mounting bracket 16, the projection 72 must get over the outer peripheral surface on the lower end side of the mounting bracket 16. Therefore, the projection 72 does not come out of the hole 62, and therefore the assembled state of the dust cover 15 to the mounting bracket 16 can be maintained well.

  Further, the hole 62 is located above the lower end of the mounting bracket 16, and the mounting bracket 16 is not divided in the circumferential direction (by the hole 62) at the lower portion thereof, and has a shape connected in the circumferential direction. Therefore, the rigidity of the fitting portion 69 in the mounting bracket 16 can be made high, and the fixing force by fitting between the fitting portion 69 and the fitting fixing portion 74 on the dust cover 15 side is increased. Can be strength and.

  In the present embodiment, the upper portion of the dust cover 15 above the protrusion 72 has an inner diameter larger than the outer diameter of the fitting portion 69 of the mounting bracket 16, and the dust cover 15 is attached through the opening at the upper end. When the outer peripheral portion 54 of the metal fitting 16 is extrapolated upward, it is a cylindrical guide portion 76 that serves as an extrapolation guide, and this guide portion 76 is not elastically fitted to the mounting metal fitting 16. Therefore, the guide portion 76 can be easily fitted to the peripheral wall portion 54 of the mounting bracket 16.

  Thereafter, the guide action of the guide portion 76 causes the protrusion 72 to reach the hole 62 over the outer peripheral surface on the lower end side of the mounting bracket 16, and the fitting fixing portion 74 on the dust cover 15 side mounts the mounting bracket. The dust cover 15 can be easily extrapolated upward with respect to the fixture up to a position where the 16-side peripheral wall portion 54 is fitted to the fitted portion 69.

  Further, the engaging hole 62 on the side of the mounting bracket 16 has a shape having a vertical hole 66 for moving and guiding the protrusion 72 on the dust cover 15 side upward, and a horizontal hole 68 extending in the circumferential direction. The horizontal hole portion 68 is provided with an inclined portion 70 having a shape that descends downward as it goes away from the vertical hole portion 66 toward the distal end in the horizontal direction, so that the dust cover 15 is extrapolated upward with respect to the mounting bracket 16. At this time, the projection 72 of the dust cover 15 is first engaged with the lower end of the vertical hole portion 66, and then the projection 72 is moved upward along the vertical hole portion 66, and then is projected by relative rotation of the dust cover 15 with respect to the mounting bracket 16. 72 can be moved along the horizontal hole 68, and the protrusion 72 can be engaged with the horizontal hole 68 in the vertical direction.

By doing so, the length over which the outer peripheral surface on the lower end side of the mounting bracket 16 is climbed before the projection 72 enters the hole 62 can be shortened as much as possible, and the dust cover 15 with respect to the mounting bracket 16 can be reduced. Assembling property can be improved.
On the other hand, by engaging the protrusion 72 in the horizontal hole portion 68, the protrusion 72 can be restrained in the vertical direction, and rattling of the dust cover 15 in the vertical direction with respect to the mounting bracket 16 can be prevented.

Further, since the horizontal hole portion 68 is located above the lower end of the vertical hole portion 66, by engaging the protrusion 72 with the horizontal hole portion 68, the fitting fixing portion 74 on the dust cover 15 side and the mounting bracket The fitting length in the vertical direction with the fitted portion 69 on the 16 side can be increased, and the fixing strength of the dust cover 15 to the mounting bracket 16 can be increased.
Further, the lateral hole portion 68 is provided with an inclined portion 70, and the protrusion 72 is moved and engaged therewith, thereby preventing the protrusion 72 from moving in the rotational direction along the horizontal hole portion 68. .

  If the vertical hole portion 66 extends downward to reach the lower end of the mounting bracket 16 and the hole portion 62 is opened at the lower end of the mounting bracket 16 and is formed in an open shape continuous with the lower end, the dust is passed through the opening. The protrusion 72 on the cover 15 side is easily inserted into the hole 62 upward from the lower end of the mounting bracket 16, and the protrusion 72 enters the horizontal hole 68 by rotating the dust cover 15, and engages with the horizontal hole 68. Can be made.

However, in this case, if the protrusion 72 located in the horizontal hole 68 reaches the vertical hole 66 by the rotation of the dust cover 15 by the action of some force, the protrusion 72 easily opens the vertical hole 66. Through the hole 62.
However, in this embodiment, since the hole 62 is provided at a position above the lower end of the mounting bracket 16 and is provided at the lower end in a discontinuous independent closed shape, such a problem does not occur.

In the present embodiment, the vertical cross-sectional shape of the dust cover 15 is a shape in which the thickness gradually increases from the lower end toward the upper end side, and the fitting fixing portion 74 is formed with respect to the lower portion than that. It is thick.
As a result, the rigidity of the fitting and fixing portion 74 that is an assembly portion with respect to the mounting bracket 16 can be effectively increased, and thereby the structure for fixing the dust cover 15 to the mounting bracket 16 can be made stronger. Can be made.

In addition, by reducing the thickness of the lower portion of the fitting and fixing portion 74, the weight of the entire dust cover 15 can be reduced, and the burden on the assembly portion 17 can be reduced. it can.
Moreover, by doing in this way, the mold release property from the shaping | molding die of the dust cover 15 as a molded article at the time of injection molding can be made favorable.

Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention provides the hole 62 on the mounting bracket 16 side and the protrusion 72 on the dust cover 15 side at three locations at equal intervals in the circumferential direction. Alternatively, it can be provided at five or more locations, and the present invention can also be applied to one in which the mounting bracket 16 is formed by bending a single bracket as shown in FIG. .
Further, the shape of the hole 62 is merely an example, and in the present invention, the shape of the hole 62 can be changed to various other shapes. The present invention can be variously modified without departing from the spirit of the present invention. It can be configured in a form to which

It is the figure which showed the dust cover assembly structure of one Embodiment of this invention with the peripheral part. It is the figure which showed the attachment metal fitting in the embodiment. It is the figure which showed the dust cover in the same embodiment. It is the figure which showed the principal part of the assembly | attachment structure to the mounting bracket of the dust cover of the embodiment. It is the figure which showed the means of the assembly in the assembly structure of the embodiment. It is sectional drawing which showed the principal part of FIG. It is the figure which showed the conventional dust cover assembly structure. It is the figure which showed the dust cover assembly | attachment structure using the attachment bracket different from FIG.

10 Shock absorber 14 Piston rod 15 Dust cover 16 Mounting bracket (rigid mounting bracket)
DESCRIPTION OF SYMBOLS 18 Vehicle body 26 Lower cushion rubber 28 Upper cushion rubber 48, 54 Peripheral wall part 62 Hole part 64, 76 Guide part 66 Vertical hole part 68 Horizontal hole part 69 Fit part 70 Inclined part (falling shape part)
72 Protrusion 74 Fitting fixing part

Claims (3)

Covers the piston rod from the outside to the cylindrical peripheral wall of a rigid fixture that attaches and fixes the piston rod of the shock absorber in the vehicle suspension mechanism to the vehicle body via a cushion rubber. At least the upper end is cylindrical A dust cover assembly structure for assembling the resin-made cylindrical dust cover in an externally fitted state at the upper end side, and the peripheral wall portion of the fixture has an engagement hole at a position above the lower end. While provided at a plurality of three or more locations in the circumferential direction in an independent closed shape that is discontinuous with the lower end,
The dust cover is formed of a resin injection molded product, and a plurality of engaging projections protruding radially inwardly on the inner peripheral surface on the upper end side by the injection molding are provided in a plurality of circumferential directions corresponding to the holes. Further, the dust cover is formed integrally with a portion, and the inner diameter of the dust cover is smaller than the outer diameter of the fitting portion on the lower end side of the peripheral wall portion of the fixture, and the fitting is attached to the dust cover. A fitting fixing part that elastically fits into the outer fitting state with a predetermined tightening allowance with respect to the joint part is prepared,
The dust cover is extrapolated upward to the peripheral wall portion of the fixture through the opening at the upper end, and the engagement protrusion is moved over the outer peripheral surface below the hole portion of the peripheral wall portion of the fixture. The fitting fixing portion is elastically fitted to the fitted portion in an external fitting state, and the dust cover is moved by the elastic fitting force and the engagement action between the hole and the projection. It is structured to be assembled to the fixture ,
In addition, the dust cover has a shape in which the vertical cross-sectional shape gradually increases in thickness from the lower end toward the upper end side, and the fitting fixing portion is thicker than the fitting fixing portion with respect to the lower portion. Dust cover assembly structure characterized by being made of meat .   2. The dust cover according to claim 1, wherein an inner diameter of the dust cover is larger than an outer diameter of the fitted portion at an upper portion of the protrusion, and the dust cover is attached to a peripheral wall portion of the fixture through the opening. A dust cover assembling structure characterized in that a cylindrical guide portion is provided for extrapolation guidance when extrapolating upward.   In any one of Claims 1 and 2, the hole portion for engagement extends vertically upward from a position above the lower end of the peripheral wall portion of the fixture, and the vertical hole portion moves and guides the protrusion upward, It has a shape that extends in the circumferential direction at a position above the lower end of the vertical hole portion, and has a horizontal hole portion that engages the protrusion at the assembly position, and the vertical hole extends toward the front end in the horizontal direction. A dust cover assembling structure characterized in that a falling shape portion having a shape that descends downward as it goes away from the portion in the circumferential direction is provided.

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