JP2008249058A - Cylinder device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic shock absorber mounted with a knuckle bracket, having required strength, rigidity and durability and reduced cost. <P>SOLUTION: A cylindrical part 3 of the knuckle bracket 2, whose cross section is approximately C-shaped and which is opened at one side of the side face is fitted to the outer periphery of an outer cylinder 1 of the hydraulic shock absorber, and it is joined thereto with a mechanical clinch. At this time, a pair of abutting porions formed at both ends of the opened side face of the cylindrical portion 3 are joined to each other with a clinch portion C1 having high separating strength, and the outer cylinder 1 and the side face of the cylindrical portion 3 are joined to each other with clinch portions C2, C3, C4 including a clinch portion having high shearing strength. Thus, the hydraulic shock absorber has required strength, rigidity and durability, improved productivity, and reduced cost. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cylinder device such as a cylindrical hydraulic shock absorber mounted on a suspension device of a vehicle such as an automobile, and more particularly to a cylinder device in which a bracket for attaching a component such as a knuckle is attached to the outer peripheral portion thereof. is there.

  For example, in a suspension strut used in a vehicle suspension device, a knuckle bracket is coupled to the outer periphery of a lower end portion of an outer cylinder (cylinder portion) of a cylindrical hydraulic shock absorber. Mounted with nuts. Generally, the outer cylinder of the hydraulic shock absorber and the knuckle bracket are joined by welding.

  However, in this joining by welding, the dimensional accuracy is reduced due to thermal strain, and there is a risk that foreign matter such as oxide scale and welding spatter generated on the inner surface of the outer cylinder will be mixed in the oil liquid, The complexity of welding work is also a problem.

Therefore, conventionally, for example, in Patent Document 1, a knuckle bracket is attached to an outer cylinder of a hydraulic shock absorber using mechanical clinch without using welding, and at this time, the mechanical clinch and the peel strength of an aspect excellent in shear strength are obtained. A technique is disclosed in which the mechanical clinch of an excellent aspect is disposed at an appropriate portion to solve the above-described welding problem and to ensure strength and rigidity necessary for the joint portion.
JP 2004-353818 A

  In the field of a cylinder device such as a hydraulic shock absorber mounted on a suspension device of a vehicle such as an automobile, it is desired to further improve the quality of the above-described bracket coupling structure and reduce the cost by rationalization.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a cylinder device capable of ensuring necessary strength, rigidity, and durability and reducing the cost.

In order to solve the above problems, the invention according to claim 1 is a cylinder device in which a substantially cylindrical cylindrical portion of a bracket is fitted to the outer periphery of the cylinder portion and joined by mechanical clinching,
The cylindrical portion has a substantially C-shaped cross-sectional shape in which one side of the side surface portion is open, and a pair of butted portions that are abutted with each other is formed at both ends of at least a part of the open side surface portion. The pair of butting parts are mechanically clinched to each other by a first clinching part having peel strength, and the cylinder part and the side part of the cylindrical part are mechanically clinched by a second clinching part including a clinching part having shear strength. It is characterized by being.
The cylinder device according to a second aspect of the present invention is the cylinder device according to the first aspect, wherein both ends of the open side surface of the cylindrical portion are extended in parallel to the radially outer side of the cylindrical portion. A pair of mounting plate portions for sandwiching the parts are formed.
According to a third aspect of the present invention, in the cylinder device according to the first or second aspect, the abutting portion is disposed at an axial end of the cylindrical portion, and a radial direction is provided at the axial end of the cylindrical portion. An outwardly extending flange portion is formed. A cylinder device according to the invention of claim 4 is characterized in that, in the configuration of any of claims 1 to 3, an outer periphery of the cylinder portion and the cylindrical portion are A filler is filled in between.
The cylinder device according to a fifth aspect of the present invention is the cylinder device according to any one of the first to fourth aspects, wherein the first clinching portion has a biting shape and the second clinching portion includes at least one dish-fitting shape. It is characterized by.

According to the cylinder device of the first aspect of the invention, the open side surface portion of the cylindrical portion is closed by the first clinching portion having peel strength, and the cylinder portion and the side surface portion of the cylindrical portion are second clinching portion having shear strength. By joining together, the coupling strength and rigidity between the cylinder part and the bracket can be increased. At this time, a bracket having a substantially C-shaped cross-sectional shape with one side surface portion that can be easily molded open can be used, and thus the manufacturing cost can be reduced.
According to the cylinder device of the second aspect of the present invention, other parts can be attached between the pair of attachment plates.
According to the cylinder device of the third aspect of the invention, the strength and rigidity of the bracket can be increased by the flange portion.
According to the cylinder device of the fourth aspect of the present invention, the gap between the cylinder portion and the bracket can be closed by the filler, and the durability can be enhanced.
According to the cylinder device of the fifth aspect of the present invention, the first clinching part can increase the peel strength by the biting shape, and the second clinching part can increase the shear strength by the dish-fitting shape.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
The cylinder device according to the present embodiment is a cylindrical hydraulic shock absorber that constitutes a suspension strut of an automobile. In this hydraulic shock absorber, a piston to which a piston rod is connected is slidably fitted in a cylinder filled with oil, and an outer cylinder is provided on the outer periphery of the cylinder. It is a double cylinder type hydraulic shock absorber in which a reservoir is formed. In response to the expansion and contraction of the piston rod, the flow of the oil liquid generated by the sliding of the piston in the cylinder is controlled by a damping force generating mechanism including an orifice and a disk valve to generate a damping force.

  As shown in FIGS. 1 to 5, the hydraulic shock absorber according to the present embodiment (only the outer cylinder 1 that is a main part is illustrated) is a bottomed cylindrical outer cylinder 1 disposed on the outer periphery of the cylinder. A knuckle bracket 2 is attached to an end on the bottom side. The knuckle bracket 2 includes a substantially cylindrical cylindrical portion 3 that fits on the outer periphery of the outer cylinder 1 and a pair of flat plate-like mounting plate portions 4 that extend in parallel from the side surface portion of the cylindrical portion 3 in the radial direction. Is formed.

  The cylindrical portion 3 has a substantially C-shaped cross-sectional shape in which a part of the side surface portion is open, and a pair of mounting plate portions 4 are bent radially outward from both ends thereof and extend in parallel to each other. Thus, the knuckle bracket 2 has a substantially U-shaped cross-sectional shape as a whole (see FIGS. 4 and 5). The upper part of the mounting plate part 4 of the cylindrical part 3 has a cross-sectional shape closed by abutting both ends in the circumferential direction, and is bent radially from the abutting part and abutted against each other in the radial direction. A pair of flat plate-like butting portions 5 extending outward are formed. The pair of butting portions 5 are integrally connected to the upper portions of the pair of mounting plate portions 4. A substantially rectangular window 3 </ b> A is opened on the side surface of the cylindrical portion 3 opposite to the mounting plate portion 4.

  At both axial ends of the cylindrical portion 3, flange portions 6 and 7 are formed which are expanded radially outward. The lower flange portion 6 is integrally connected to the lower ends of the pair of mounting plate portions 4. Further, the flange portion 7 on the upper end side is integrally connected to the upper ends of the pair of butting portions 5. Further, a plurality of reinforcing ribs 8 extending across these connecting portions (folded portions) are bulged between the cylindrical portion 3 and the mounting plate portion 4 and the butting portion 5.

  In the pair of mounting plate portions 4, two bolt holes 9 are formed at portions facing each other. And the edge part of the knuckle (not shown) which supports an axle shaft is fitted between a pair of attachment plate parts 4, a bolt (not shown) is inserted in the bolt hole 9, and a nut (not shown) is inserted. The knuckle is attached to the knuckle bracket 2 by tightening.

  The knuckle bracket 2 is formed by integrally forming the above-described parts, and has a substantially U-shaped cross-sectional shape as a whole. For example, the knuckle bracket 2 can be easily press-molded from a single plate material.

  The outer cylinder 1 and the knuckle bracket 2 are joined by clinch portions C1, C2, C3, and C4 formed by mechanical clinch. The mechanical clinch squeezes the stacked plate material from above and below using a punch P and a die D as shown in FIG. 7, and plastically deforms it into an uneven shape as shown in FIGS. 6 (A), (B), and (C). Therefore, it joins mechanically by uneven | corrugated fitting.

  As will be described later, the pair of butting portions 5 of the knuckle bracket 2 are joined by a clinch portion C1 (first clinch portion) having high peel strength. Thereby, the outer cylinder 1 and the cylindrical part 3 can be put into a press-fit (tightened) state with a cross-sectional shape in which the upper part of the cylindrical part 3 is completely closed, and the fatigue strength against bending is improved by increasing their coupling rigidity. Can be made.

  The cylindrical part 3 and the outer cylinder 1 include clinch parts C2, C3, and C4 that include a plurality of clinch parts (described later) with high shear strength that are arranged along the circumferential direction at the upper part, intermediate part, and lower part of the cylindrical part 3, respectively. It is joined by (second clinching part). As shown in FIG. 4 (showing the second clinching part C2), the clinching parts C2, C3, and C4 are respectively arranged at a total of four places at two positions facing each other in the diameter direction. The clinch portions C1, C2, C3, and C4 are appropriately combined with three types of mechanical clinch shown in FIGS. 6 (A), (B), and (C).

  Next, as an example of the case where the knuckle bracket 2 made of the same material and having a plate thickness of 2.6 mm is attached to the outer tube 1 made of STKM12B having a diameter of 45 mm and a plate thickness of 2.3 mm, FIGS. The mechanical clinch of three aspects shown to C) is demonstrated.

  The mechanical clinch shown in FIG. 6 (A) has a dish-fitting shape. That is, in the joint portion, the joint surface of the cylindrical portion 3 and the outer tube 1 has a shape with a reduced diameter with respect to the overhang direction (downward in FIG. 6), and almost no peeling strength can be expected, but shear strength and bending fatigue strength. It is excellent. The dimension of each part of the punch and die used for this mechanical clinch is shown in FIG. Referring to FIG. 7, punch P has a stepped tip portion in which a small-diameter tapered portion at the tip and a cylindrical base portion having a large diameter are smoothly connected with a radius of curvature R1 = 2.0 mm. Yes. Dies D diameter D1 = 10.0mm, punch P diameter D2 = 14.0mm, base diameter D3 = 6.6mm, taper tip diameter D4 = 4.6mm, tip length L1 = 8.0 mm, length L2 from the base end of the tip portion to the base end of the taper portion = 6.0 mm, length L3 = 5.0 mm of the base portion, angle A1 = 135 ° between the side surface portion and the curved surface portion of the base portion The angle A2 of the taper portion is 2.9 °, and the depth d of the die D is 1.0 to 1.4 mm. Thereby, mechanical clinching is performed so that the bottom plate thickness X of the joint portion is about 2.0 to 3.0 mm.

  The mechanical clinch shown in FIG. 6B has a biting shape. That is, in the joint portion, the joint surface of the cylindrical portion 3 and the outer tube 1 has a shape having a portion that expands in the projecting direction (downward in FIG. 6), and has a high peel strength. This has a shear strength of about 5.0 kN or more per point and a peel strength of about 2.5 kN or more. Using this as the die diameter D1 = 10 mm, the die depth d = 1.4 mm, and the punch diameter D3 = 5.4 mm, mechanical clinch is performed so that the bottom plate thickness X = 1.1 mm of the joint portion. .

The mechanical clinch shown in FIG. 6 (C) is obtained by performing mechanical clinch with respect to that shown in FIG. 6 (B) so that the bottom plate thickness X of the joint portion is 1.5 mm. Here, the value of the bottom plate thickness X of the joint mainly controls the peel strength, and the bottom plate thickness X is increased from X = 1.1 mm in FIG. 6B to X = 1.5 mm. As a result, the peel strength is considerably reduced. Further, since the bottom plate thickness X of the joint portion is the wall thickness of the outer cylinder 1, it also affects the corrosion resistance of the outer cylinder 1. That is, by setting the bottom plate thickness X = 1.5 mm, the corrosion resistance can be improved while ensuring a certain degree of peel strength.
It should be noted that the bending fatigue strength is significantly reduced in the case of FIGS. 6B and 6C as compared to that in FIG.

  The clinch portion C1 that joins the pair of butted portions 5 of the knuckle bracket 2 requires a large peel strength, but a shear force hardly acts so that a large peel strength can be obtained. FIG. Need to use clinch. On the other hand, the clinch portions C2, C3, and C4 that join the cylindrical portion 3 and the outer cylinder 1 of the knuckle bracket 2 have low peel strength requirements. Therefore, the mechanical clinch shown in FIGS. Can be used together. In this case, the clinch portion C2 disposed at the upper part of the cylindrical portion 3 has the greatest demand for bending fatigue strength, and therefore the mechanical clinch of FIG. 6 (A) having excellent shear and bending fatigue strength is used. In addition, since the clinch portions C3 and C4 have a small requirement for bending fatigue strength, the mechanical clinch shown in FIG. 6A or 6C may be appropriately selected according to the peel strength requirement. Three preferred embodiments 1 to 3 of preferred combinations of the mechanical clinch shown in FIGS. 6A, 6B, and 6C used for the clinch portions C1 to C4 are shown in the chart of FIG.

  By the way, a slight gap is generated in the fitting portion between the outer cylinder 1 and the cylindrical portion 3 of the knuckle bracket 2, which causes a corrosion problem. Therefore, by applying a filler (or adhesive) between the outer cylinder 1 and the cylindrical portion 3, the gap is closed, the adhesion of the paint is improved and the corrosion resistance is improved, and the outer cylinder 1 and the knuckle bracket are also provided. The bond strength with 2 can be increased.

  As a specific example, a one-component epoxy compound resin is applied to the joint surface between the outer cylinder 1 and the outer cylinder 3. For example, a thermosetting filler (adhesive) is applied to the joint surface between the outer cylinder 1 and the knuckle bracket 2 and joined by mechanical clinching, and then is subjected to cationic electrodeposition coating. At this time, the filler is completely cured by the baking temperature of the cationic electrodeposition coating. Thereby, the gap can be completely closed, the adhesion of the coating can be improved to improve the corrosion resistance, and the bonding strength can be increased to improve the reliability.

  In this way, the knuckle bracket 2 can be attached to the outer cylinder 1, and the cylinder device that can secure the necessary strength, rigidity, and durability, is excellent in productivity, and can be reduced in cost can be provided. .

  In the above embodiment, the present invention has been described with respect to the case where the outer cylinder 1 of the hydraulic shock absorber of the suspension strut and the knuckle bracket 2 are coupled. However, the present invention is not limited to this, and the vehicle height of the active suspension is also described. The present invention can be similarly applied to a cylinder device in which other parts such as a knuckle bracket or other bracket, or a spring seat are coupled to a cylinder portion of another cylinder device such as an adjustment cylinder.

It is a side view which shows the outer cylinder of the hydraulic shock absorber with which the knuckle bracket which concerns on one Embodiment of this invention was attached. It is a side view which shows the state before the attachment to the outer cylinder of the knuckle bracket shown in FIG. It is the side view seen from the attachment plate part side of the knuckle bracket shown in FIG. It is a cross-sectional view by the AA line of FIG. It is a cross-sectional view by the BB line of FIG. It is a longitudinal cross-sectional view of the clinching part which shows the three aspects of the mechanical clinching used by one Embodiment of this invention. It is a figure which shows the dimension of each part of the punch and die | dye used for the mechanical clinch shown to FIG. 6 (A). It is a graph which shows Embodiments 1-3 which are the preferable combination examples of the mechanical clinch used for embodiment shown in FIG.

Explanation of symbols

  1 outer cylinder (cylinder part), 2 knuckle bracket (bracket), 3 cylindrical part, 5 butting part, C1 clinch part (first clinch part), C2, C3, C4 clinch part (second clinch part)

Claims (5)

A cylinder device in which the substantially cylindrical cylindrical portion of the bracket is fitted to the outer periphery of the cylinder portion and joined by mechanical clinch,
The cylindrical portion has a substantially C-shaped cross-sectional shape in which one side of the side surface portion is open, and a pair of butted portions that are abutted with each other is formed at both ends of at least a part of the open side surface portion. The pair of butting parts are mechanically clinched to each other by a first clinching part having peel strength, and the cylinder part and the side part of the cylindrical part are mechanically clinched by a second clinching part including a clinching part having shear strength. A cylinder device characterized by being made. A pair of mounting plate portions are formed at both ends of the open side surface portion of the cylindrical portion so as to extend in parallel to the radially outer side of the cylindrical portion and sandwich other components. The cylinder device according to claim 1. The said abutting part is arrange | positioned at the axial direction edge part of the said cylindrical part, The flange part extended in a radial direction outer side is formed in the axial direction edge part of this cylindrical part, The Claim 1 or 2 characterized by the above-mentioned. The cylinder device described in 1. The cylinder device according to any one of claims 1 to 3, wherein a filler is filled between an outer periphery of the cylinder portion and the cylindrical portion. 5. The cylinder device according to claim 1, wherein the first clinching portion has a biting shape, and the second clinching portion includes at least one dish surface matching shape.

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