JPH11294512A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorber which is lightweight, low-cost and made of aluminum alloy for receiving a bending load of such as a suspension strut. SOLUTION: A base shell 1 having at its lower end a bracket receiving part 15 of flange shape is formed by a cold forging of aluminum alloy, a bracket part 2 is integrally formed with extruded shape of aluminum alloy, and the base shell 1 is inserted and fitted to an inside of the bracket part 2 to constitute main construction, whereby a strength for a bending load is applied. Further, an upper surface of the bracket receiving part 15 is formed such that an angle between the upper surface and a lower end of the bracket part 2 is a predetermined bevel angle, or a side surface of the bracket part 2 is formed with a cutout part for welding to carry out welding. A projected line is formed to an outer periphery of the base shell 1. and a recess groove is formed to an inner periphery of the bracket part 2, and the projected line and the recess groove are engaged to each other thereby to apply a strength to an external force around the outer periphery. Further, an upper end of the projected line acts as a spring receiving part, whereby enough support strength can be applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber which functions as a damper by absorbing repulsive energy of a wheel supporting mechanism in a suspension structure of an automobile or the like. In particular, the present invention relates to a shock absorber that functions as a suspension strut by bearing a part of a bending moment against an external force as a suspension arm.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of protection of the global environment, it has been required to reduce carbon dioxide emissions and promote recycling by energy saving, and the impact on automobiles is great. There is nothing. Aluminum alloy materials are effective in reducing structural weight and are easily recyclable.Therefore, aluminum alloys for automobile structures and parts are being promoted.However, aluminum alloy materials and conventionally used steel materials are different from each other. Due to differences in materials such as strength and hardness as well as specific gravity, various problems occur when the structure and manufacturing process of a steel part are applied directly to an aluminum alloy material. In recent years, the use of so-called suspension struts, in which shock absorbers have the function of suspension arms, are incorporated, and the use of MacPherson suspensions has become widespread because the suspension structure of automobiles can be made relatively simple and the effective volume inside the vehicle can be widened. doing.

Conventionally, these shock absorbers functioning as suspension struts are generally constructed by welding a steel pipe (base shell) and a steel press part (bracket, spring seat). Parts are excellent in both rigidity and strength in material,
There is a limit to the material for reducing the weight, and structural measures such as an integrated structure or a cross-sectional structure according to the load distribution also complicate the processing steps and are difficult to adopt from the viewpoint of manufacturing costs. In addition, the above-mentioned structure formed by welding a pipe and a pressed part also has a structure in which a bracket for fixing a bracket by winding and fastening a hollow base shell, which is a mounting structure for the base shell, and a bracket for mounting the bracket on the axle side are separate bodies. Since these are formed and welded together to the base shell, the number of parts is increased and the weight is increased, and the manufacturing cost cannot be reduced due to the large number of manufacturing steps.

As for shock absorbers used for suspensions of these automobiles and the like, those of a type that does not have a link function such as a suspension arm and bears only an axial load have been realized by an aluminum alloy. A structure that also functions as a suspension arm like a so-called suspension strut is expected to have a lighter weight effect than a shock absorber that works alone.However, in addition to a function as a damper, a suspension strut has a bending moment of external force. Therefore, the requirements for bending rigidity and bending strength are extremely severe, and it has been difficult to use an aluminum alloy.

That is, in the suspension strut, bending and stress concentrate near the mounting position of the bracket below the base shell of the shock absorber. In order to respond to this, it is necessary to greatly increase the wall thickness and the like to improve the strength. Not only did the usage increase significantly, but the weight also increased, but aluminum alloy materials had a high cost ratio due to the high material cost ratio. In addition, if the members are joined by welding in the same way as steel suspension struts, the aluminum alloy has a high thermal conductivity and exhibits a heat treatment effect at a relatively low temperature. And softens the strength. In the above-described conventional structure in which the base shell and the bracket part are combined and welded, this structure corresponds to the vicinity of the above-mentioned stress concentration portion, and therefore, such a structure cannot be employed for aluminum alloying.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been devised to solve such a problem, and is not inferior to a steel suspension strut in terms of strength and rigidity, and is easy to manufacture. It is an object of the present invention to provide a shock absorber for an automobile made of an aluminum alloy which does not cause a significant increase in cost, particularly a shock absorber suitable as a suspension strut.

[0007]

SUMMARY OF THE INVENTION In order to achieve the object, the present invention comprises a base shell formed by cold forging of an aluminum alloy and a bracket portion integrally formed by an extruded aluminum alloy material. A shock absorber for automobiles, which receives a bending load formed by inserting and fitting the base shell into a main part, and forming a flange-shaped bracket part receiving part by cold forging at a lower end part of the base shell. In addition, an inclined surface is formed on the upper surface of the flange-shaped bracket portion receiving portion at the lower end of the base shell, and the inclination of the upper surface of the flange is sufficiently welded between the bracket portion and the welding portion for sufficient penetration. The bracket is formed at an included angle so that the bracket can be inserted and fitted from the upper end of the base shell. Are those formed by welding,

In addition, a notch for welding is formed on a side surface of the cylindrical portion of the bracket, and the base shell and the bracket are welded and integrated at the notch. An outer peripheral portion of the shell is formed with a ridge extending in the axial direction, a bracket portion is formed with a concave groove to be fitted with the ridge, and both are fitted in the axial direction. The projecting ridge is formed from the middle of the base shell in the axial direction, and the upper end of the projecting ridge supports a load applied to the spring seat as a receiving portion of the spring seat inserted and fitted from the upper part of the base shell,
Still further, the shock absorber is a suspension strut that functions as a suspension arm.

[0009]

According to a first aspect of the present invention, a base shell, which is required to have a high dimensional accuracy as a shock absorber, is formed by cold forging, and a complicated cross-sectional structure such as a projecting portion such as a bracket for mounting is provided. The necessary brackets are formed by extrusion and formed by a processing method suitable for each aluminum material, thereby satisfying both structural requirements and productivity and cost requirements. The absorber can be provided at low cost. In particular, the fitting structure between the base shell and the bracket portion thus formed is
Since both can be maintained in close contact, the bending load applied below the base shell can be smoothly transmitted to the bracket and reinforced, and a special structure such as increasing the thickness of the entire base shell is adopted. The predetermined strength and rigidity can be imparted to the locations where the bending and stress applied thereto are concentrated without any problem. According to the configuration of the second aspect, when the bracket portion is inserted and fitted into the base shell and welded, it can be easily and accurately set at a predetermined position without taking a special jig or a temporary fixing means. it can.

Further, the flange-shaped bracket portion receiving portion of the present invention has a positioning function when the bracket portion is fitted to the base shell, and has a predetermined inclined surface between the bracket portion and the cut surface of the bracket portion. Since it forms an angle groove, it is possible to obtain the setting and groove shape at the time of welding without using a special jig or temporary fixing means, and, for example, after fitting the bracket part to the base. By welding while rotating the shell while supporting it horizontally, welding can be performed under certain welding conditions, and the welding operation can be easily performed.

According to the notch for welding formed on the side surface of the bracket portion according to the fourth aspect, welding can be performed avoiding the vicinity of the upper end of the bracket portion fitting portion where bending and stress concentrate.
It is possible to obtain a strong integrated welded structure that does not affect the base shell such as softening due to heat input due to welding heat input and strength reduction. Furthermore, since the notch portion can be formed at an arbitrary position along the outer periphery of the base shell, a sufficient weld bead length can be secured according to the strength requirement, and the welding heat input is reduced by the bracket portion. It is possible to avoid a dimensional change such as a distortion due to a thermal effect at the time of welding with respect to a base shell which requires dimensional accuracy in order to disperse and escape.

According to the fifth aspect of the present invention, the fitting structure formed by the ridges and the concave grooves formed on the base shell and the bracket portion provides a sufficient strength against an external force around the axis applied to the shock absorber. By setting the position where the ridge is formed below the mounting position of the spring seat of the base shell and the upper end thereof as the receiving portion of the spring seat fitted from above the base shell, a supporting structure that receives the downward load together with the stopper function. Sufficient strength can be provided. Further, the shock absorber formed in this manner can also function as a suspension arm, and thus can function as a suspension strut.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and manufacturing process of a shock absorber according to the present invention will be specifically described below with reference to the drawings. JIS-A6063 or JI as an aluminum alloy material for the base shell formed by cold forging
T8 heat treatment is performed after cold forging using T4 material of S-A6061, and as the aluminum alloy material of the bracket part formed by extrusion, a material obtained by subjecting JIS-A6063 to T5 heat treatment or a material obtained by subjecting JIS-A6061 material to T6 heat treatment is used. used.

FIG. 1 is an overall schematic view of a shock absorber according to the present invention, wherein 1 is a base shell having a hollow tube structure, and 2 is a bracket portion. The rod 5 connected to the piston of the shock absorber is fixed to the vehicle body side strut tower 40 with a screw portion 6, and the bracket portion 2 is attached to the axle side by the bracket 21, and is connected to the lower surface of the vehicle body side strut tower 40 and the base shell. A load applied to the axle is supported via a spring 8 interposed between the fixed spring seat 7. This type of shock absorber absorbs the repulsive force of this spring by the damper action, but since one end is fixed to the vehicle body as a suspension arm, the bending load is applied from the vehicle body side due to the load, especially the bending load Concentrates near the fitting position of the bracket portion below the base shell.

In the shock absorber according to the present invention, the bracket portion has a structure in which the bracket portion is fitted to a portion below the base shell where the bending load is concentrated. By forging, and by improving the processing accuracy of the inner peripheral surface by extruding the bracket part as an integral structure, the fitting part can be integrated in close contact, so the bending load applied to the base shell is transmitted directly to the bracket part The load can be shared. For this reason, it is not necessary to increase the thickness of the base shell in accordance with the location where the bending load is concentrated so as to provide the entire rigidity and strength, and it is possible to achieve weight reduction with a simple structure.

FIG. 2 shows a base shell of the shock absorber of the present invention. The base shell 1 is formed by cold forging, and is formed in a cylindrical shape with a bottom. A flange-like bracket receiving portion 15 is provided at the bottom, and the bracket is fixed by welding at the bottom of the base shell as described later. In this case, the inclination angle θ is formed so that a welding groove having a predetermined angle is formed between the lower end cross section of the bracket and the bracket. FIG. 3 shows the bracket part 2 of the present invention. The bracket portion is formed as a continuous section having a predetermined cross-sectional shape provided with a predetermined bracket 21 by extruding an aluminum alloy, and is cut into a predetermined length to form a mounting hole 22 and is unnecessary depending on the mounting portion structure. The part is cut off and shaped into the shape shown by the broken line. 2
Reference numeral 5 denotes a notch portion serving as a welding portion described later.

In the shock absorber of the present invention, as shown in FIG. 4, a bracket 2 formed by cutting an extruded material into a base shell 1 formed by cold forging is inserted and fitted from above, as described above. A flange-shaped receiving portion 15 formed at the bottom of the base shell, and the gap and angle between the upper surface of the flange portion and the cut surface of the lower end of the bracket portion have a predetermined groove shape. Fix by welding. According to this welding structure, the welded portion is secured at a location sufficiently distant from the location where the bending stress of the base shell is concentrated, and predetermined beveling is simultaneously performed by cold forging, and the extruded material is When cutting out as a bracket part, it is only necessary to cut at a right angle, so there is no waste of material.

FIG. 5 shows another embodiment in which a notch opening 25 is provided on the side surface of the bracket portion when the base shell is welded to the bracket portion, and the edge of the notch is used for welding to the base shell. . In the figure, a pair or an appropriate number of notches 25 are formed symmetrically on the side surface of the bracket portion, and the edges are welded to the base shell as welding portions 26.
According to this structure, a welding portion can be secured at a position apart from the vicinity of the upper edge portion of the bracket portion below the base shell where bending is concentrated on the base shell. Also, because it is in the area reinforced by the bracket, there is room for strength,
The required length of the welded portion in terms of welding strength can be ensured by welding the entire vertical and horizontal edges of the notch or, if necessary, increasing the number of notches.

FIGS. 6 and 7 show an axially extending ridge 30 and a concave groove 31 for fitting the ridge 30 on the outer periphery of the base shell and the inner periphery of the bracket portion, respectively. , And can firmly have a fixing action. The base shell is bent as described above, but since the ridge can provide strength as a reinforcing structure, it is lightweight and has the effect of cost reduction. The height and width of the cross-sectional shape of the ridge may be appropriately set in accordance with the strength and processing convenience. Also, as shown in FIG. 8, the ridge on the outer periphery of the base shell is partially formed, and its upper end 33 is a receiving portion for welding the spring seat 7 for receiving the suspension spring 8 as shown in the assembly external view of FIG. Thus, sufficient strength for bearing the load can be provided. In order to make the ridge up to the spring seat receiving position in the middle of the base shell and make the upper portion into the shape of the non-convex portion 32, the ridge may be cut off after forming, or may be finished in a predetermined shape by forging in advance. .

[0020]

As described above, according to the present invention, energy can be saved by forming the structure of a shock absorber receiving a bending load such as a suspension strut by a structure and a processing method suitable for the characteristics of an aluminum alloy material. In addition to achieving weight reduction by using an aluminum alloy suitable for recycling, productivity can be improved, and manufacturing cost can be easily reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view of an external appearance of a shock absorber according to the present invention.

FIG. 2 is a base shell of the shock absorber of the present invention.

FIG. 3 is a bracket part of the shock absorber of the present invention.

FIG. 4 is a sectional view of a welded portion between a base shell and a bracket portion.

FIG. 5 is an embodiment in which welding is performed by using a notch edge of a bracket portion.

FIG. 6 shows an embodiment in which a ridge is formed on a base shell.

FIG. 7 is an embodiment in which a concave groove is formed in a bracket portion.

FIG. 8 shows an embodiment in which the upper end of the ridge on the outer periphery of the base shell is used as a spring seat receiving portion.

FIG. 9 is an assembly diagram in which the upper end of a ridge on the outer periphery of the base shell is a spring seat receiving portion.

[Explanation of symbols]

1: Base shell 2: Bracket section 5: Rod 6: Screw section 7: Spring seat 8: Suspension spring 15: Bracket section receiving section
21: Bracket 22: Hole 25: Notch for welding 26: Notch edge weld 30: Protrusion 3
1: concave groove 32: non-convex portion 33: upper end of the ridge 4
0: Strut tower

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FIF16F 9/32 B (72) Inventor Genji Hotta 1-34-1 Kambara, Kambara-cho, Anbara-gun, Shizuoka Nippon Light Metal Co., Ltd. Group Technology Center (72) Inventor Kaoru Ishido 1-34-1, Kambara, Kambara-cho, Abara-gun, Shizuoka Prefecture Nippon Light Metal Co., Ltd.Group Technology Center (72) Inventor Hiroyuki Mochizuki 1-34-1, Kambara, Kambara-cho, Anbara-gun, Shizuoka Japan Light Metal Corporation Group Technology Center (72) Inventor Takashi Sasamoto 1-34-1, Kambara, Kambara-cho, Anbara-gun, Shizuoka Prefecture Nippon Light Metal Corporation Group Technology Center

Claims (7)

[Claims] 1. A main structure comprising a base shell formed by cold forging of an aluminum alloy and a bracket portion integrally formed by an extruded member of an aluminum alloy, wherein the base shell is inserted and fitted into the bracket portion. Automotive shock absorbers that receive bending loads. 2. The automobile shock absorber according to claim 1, wherein a flange-shaped bracket receiving portion is formed at a lower end portion of said base shell by cold forging. 3. An inclined surface is formed on an upper surface of a flange-shaped bracket portion receiving portion at a lower end portion of the base shell, and the inclination of the upper surface of the flange portion is sufficiently and sufficiently sound-penetrated when welding with the bracket portion. 3. The automobile according to claim 2, wherein the bracket is formed at an included angle for obtaining a welded portion, the bracket is inserted and fitted from the upper end of the base shell, and the bracket and the bracket receiving portion are welded. For shock absorber. 4. A notch for welding is formed on a side surface of the cylindrical portion of the bracket, and the base shell and the bracket are welded and integrated at the notch. 4. The shock absorber for an automobile according to 2, 3 or 4. 5. The base shell has an outer peripheral portion formed with a ridge extending in the axial direction, and a bracket portion is formed with a concave groove to be fitted with the ridge, and both are fitted in the axial direction. The automobile shock absorber according to claim 1, 2, 3, or 4. 6. The base shell has a ridge formed in the middle of the base shell in the axial direction, and the upper end of the ridge serves as a receiving portion of the spring seat inserted and fitted from the upper portion of the base shell to support a load applied to the spring seat. The automobile shock absorber according to claim 5, wherein 7. The automobile shock absorber according to claim 1, wherein said shock absorber is a suspension strut functioning as a suspension arm.