JP2003294020A - Shaft integrated member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely fix together a steel shaft member and aluminum alloy body member. <P>SOLUTION: A male screw 32 of the steel shaft member 30 is engaged with a female screw hole 24 of the aluminum alloy body member 10 until a flanged portion 34 is seated on a seated surface 22 of the body member 10. A steel ring member 16 is inserted from a supporting shaft 14 side while a fitting portion 46 is fitted into a fitting hole 48. A serration 50 is formed on an outer periphery of the flanged portion 34 of the shaft member 30 at a whole periphery and full length, and a serration hole 54 is formed on an inner periphery of the ring member 16 at a full length and whole periphery. One end portion of the serration hole 54 of the ring member 16 at an axial direction is interference- fitted on an outer periphery of a boss portion 20 of the body member 10, and other end portion of the serration hole 54 is fitted to the serration 50 of the flanged portion 34 in a relative-rotation failed state. A bush 12 is retained on a supporting shaft 14 of the shaft member 30. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft member in which a steel shaft member is fixed to a body member made of an aluminum alloy.

[0002]

2. Description of the Related Art One example of this type of shaft-equipped member is a vehicle suspension arm (hereinafter, simply referred to as an arm). Although the arm is made of an aluminum alloy to reduce the weight, it is difficult to make the entire arm of the aluminum alloy. For example, in the L-type lower arm and the A-type lower arm, it is difficult to ensure strength if the support shaft portion that supports the bush is integrally formed of aluminum alloy. Therefore, Japanese Patent Laid-Open No. 7-186651 proposes that a steel shaft member is fixed to a body member made of an aluminum alloy to form a bush support shaft portion.

In this suspension arm, the shaft member and the main body member are fixed as follows.
The male screw portion provided on the shaft member is screwed into the female screw hole provided on the main body member until the flange portion provided on the shaft member is seated on the seat surface of the main body member, and the flange portion is integrated with the main body member. It is fitted with a gap left in the cylindrical protrusion provided on the. Serrations are formed on the outer peripheral surface of the flange portion, and the inner peripheral surface of the protruding portion is strongly pressed against the outer peripheral surface of the flange portion by deforming the protruding portion inward in the radial direction by a caulking tool. Are engaged with each other to prevent the shaft member from loosening. However, since the main body member is deformed by caulking, it is difficult to stably secure the contact surface pressure between the flange portion and the seat surface of the main body member, and the screwed portion between the shaft member and the main body member is loosened. It will be easier. Further, there is a problem that a special tool for caulking is required and the cost becomes high.

[0004]

In view of the above circumstances, the present invention is capable of securely fixing a steel shaft member and an aluminum alloy main body member, and The object of the present invention is to make it possible to realize it at low cost, and the present invention provides a shaft member having the following aspects. Similar to the claims, each mode is divided into paragraphs, each paragraph is numbered, and the numbers of other paragraphs are referred to as necessary. This is merely for facilitating the understanding of the present invention, and the technical features and combinations thereof described in the present specification should not be construed as being limited to those described in the following respective sections. . Further, when a plurality of items are described in one section, it is not always necessary to adopt the plurality of items together. It is also possible to select and use only some of the items.

In the following items, item (1) corresponds to item 1, item (2) is item 2 and item (3) is item 3
And (4) and (5) are combined in claim 4,
The combination of (6) and (7) corresponds to claim 5, respectively.

(1) A main body member made of aluminum alloy, having a boss portion, a seat surface formed at the tip of the boss portion, and a female screw hole formed at a right angle to the seat surface, and made of steel. A male screw portion that can be screwed into the female screw hole, a flange portion that can be seated on the seat surface and has a non-circular cross-sectional shape, and the flange portion that extends to the opposite side of the male screw portion. A shaft member having a shaft portion, and steel, wherein the male screw portion is screwed into the female screw hole until the flange portion is seated on the seat surface, and is fitted to the flange portion such that it cannot rotate relative to the flange portion. A member with a shaft that is fitted together and that includes the boss portion and a ring member that is tightly fitted.

With the male screw portion of the shaft member screwed into the female screw hole of the main body member and the flange portion of the shaft member screwed onto the seat surface of the boss portion of the main body member, the steel ring member is attached to the flange portion. If the ring member is fitted so that it cannot rotate relative to it, and the boss portion is tightly fitted, the ring member will be fixed to the main body member and will function as an integral body, and the ring member will fit into the flange portion so that it cannot rotate relative to it. The relative rotation between the shaft member and the main body member is prevented. Therefore, the male screw portion of the shaft member is prevented from loosening with respect to the female screw hole of the body member, and the shaft member is reliably prevented from being separated from the body member.
When the ring member is made of steel having hardness and strength higher than that of the main body member, it is possible to reliably prevent the shaft member from loosening. The ring member is a member having a simple shape and can be manufactured at low cost. Also, by tightly fitting the steel ring member from the outside to the boss portion of the aluminum alloy main body member, which is weak in strength, a force for compressing the boss portion of the main body member acts, which causes the inner circumference of the boss portion. The surface is strongly pressed against the outer peripheral surface of the shaft member, and the boss portion is deformed by the load acting on the shaft member in the use state, and the fixing strength of the shaft member to the main body member is well prevented from being lowered. Further, due to the tight fitting of the ring member, a compressive stress is generated in the boss portion, so that the fatigue strength of the boss portion is improved. The flange portion has a non-circular cross-sectional shape, such as one or more protrusions protruding outward in the radial direction or notches recessed inward in the radial direction on the outer peripheral surface. By fitting the ring member so as not to rotate relatively, the rotation of the flange portion can be prevented with a simple configuration. Further, since the ring member fitted to the flange portion so as not to rotate relative to each other is fitted into the boss portion of the main body member to prevent relative rotation with respect to the main body member, the relative rotation position between the flange portion and the main body member is prevented. Can be in any position. Since the male screw portion of the shaft member is screwed into the female screw hole of the main body member until the flange portion is seated on the seat surface, the phase of the flange portion is usually not constant in that state. Therefore, the phase of the ring member fitted to the flange portion so as not to rotate relative to each other is not constant, but there is no problem because the ring member can be tightly fitted at any relative rotation position with the boss portion of the main body member. is there. (2) The shaft member according to item (1), wherein the flange portion has a non-circular cross-sectional shape by forming serrations on the outer peripheral surface of the flange portion. When the serration is formed on the outer peripheral surface of the flange portion, it is desirable that the serration hole is also formed in the ring member that is fitted so as not to rotate relative to the serration. If the ring member is formed with one or more teeth that fit between two adjacent teeth of the serration, the ring member can be fitted into the flange portion so as not to rotate relative to each other. When the fitting is done, relative rotation between the flange portion and the ring member is prevented particularly strongly. (3) A fitting portion having a circular cross-sectional shape is provided between the male screw portion and the flange portion, while the fitting portion is provided between the female screw hole of the main body member and the seat surface. The shaft member according to item (1) or (2), which is provided with a fitting hole for fitting. The fitting portion and the fitting hole portion may be loosely fitted, but it is preferable that the fitting portion and the fitting hole portion are tight fit or intermediate fit. This is because in the latter case, the shaft member is firmly held by the main body member, and wobble of the shaft member can be prevented particularly well. (4) A serration hole is formed in the ring member, and a part of the serration hole is fitted with the serration of the flange portion, and the serration hole is tightly fitted on the outer peripheral surface of the boss portion. The shaft member according to any one of (3). By forming a serration hole in the ring member, with the male screw part of the shaft member screwed into the female screw hole of the main body member, fit the ring member to the serration of the flange part, and then part of the serration hole Can be tightly fitted on the outer peripheral surface of the boss portion. Thereby,
The relative rotation between the main body member and the shaft member is blocked by the ring member, and the loosening of the male screw portion of the shaft member with respect to the female screw hole of the main body member can be reliably prevented. In addition, the formation of the serration holes facilitates tight fitting into the boss portion of the ring member, and at least the tops of many teeth of the serration holes bite into the outer peripheral surface of the relatively soft boss portion. Relative rotation between the member and the boss portion is favorably prevented. (5) The shaft member according to item (4), wherein the serration hole is formed over the entire length of the ring member. It is possible to form serrations only on one end of the inner peripheral surface of the ring member to form serration holes. However, forming the serration holes over the entire length of the ring member facilitates the formation of the serration holes. (6) The shaft member according to any one of (1) to (5), wherein the main body member is a main body member of an arm of a suspension device.
INDUSTRIAL APPLICABILITY The present invention is suitable for an arm of a suspension device, particularly an L-shaped lower arm or an A-shaped lower arm which is relatively complicated in shape and is preferably manufactured by forging. In the arm of the suspension device, its main body member is often made of an aluminum alloy for weight reduction, but a large load often acts on the shaft member. Therefore, not only when the shaft member is screwed into the main body member, but also when the outer peripheral surface of the flange portion is brought into close contact by caulking a part of the main body member as described above, Although there is a problem of easy loosening, such loosening of the shaft member is favorably prevented according to the present invention. (7) The shaft member according to item (6), wherein the shaft member is a support shaft for the bush. When the shaft member is the support shaft of the shock absorbing bush provided at the connecting portion between the arm and another member, a large load such as bending or twisting repeatedly acts while the vehicle with the arm assembled is running. To do. Moreover, it is desirable that the diameter of the support shaft is as small as possible. In this respect, according to the present invention, since the support shaft made of steel having hardness and strength higher than that of the aluminum alloy is firmly fixed to the main body member, the support shaft itself is damaged while making the support shaft thin. Also, it is possible to reliably prevent the support shaft from coming off the main body member. (8) The member with a shaft according to item (7), wherein the arm is an L-shaped lower arm.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an arm of a suspension device as a member with a shaft according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an L-shaped lower arm provided on the front wheel side of a vehicle suspension device according to an embodiment of the present invention. The L-shaped lower arm includes a main body member 10, a support shaft 14 that is provided integrally with the main body member 10, and that supports a shock absorbing bush 12 (see FIG. 2) that is provided at a connection portion with another member, and a ring member. 16 and 16.

The body member 10 is made of an aluminum alloy and is formed by forging in this embodiment.
By machining the forged material, a cylindrical boss portion 20, a seat surface 22 formed at the tip of the boss portion 20, and a female screw hole 24 formed at a right angle to the seat surface 22.
The main body member 10 is provided with. The support shaft 14 is composed of the shaft member 30 shown in FIGS. 2 and 4. The shaft member 30 is made of steel and has a female screw hole 24.
A male threaded portion 32 that can be screwed with, a flange portion 34 that can be seated on the seating surface 22 and has a non-circular cross-sectional shape, and a shaft portion that extends to the side opposite to the male threaded portion 32 with respect to the flange portion 34. And a support shaft 14 that is A male screw portion 38 is formed at the tip of the support shaft 14. A tool engaging portion 40 having a hexagonal cross-sectional shape is formed in a portion closer to the flange portion 34 than the male screw portion 38 in the axial direction of the support shaft 14. A fitting portion 46 having a circular cross section is formed between the male screw portion 32 and the flange portion 34. On the other hand, a fitting hole portion 48 to be fitted with the fitting portion 46 is formed between the female screw hole 24 of the main body member 10 and the seat surface 22. The fitting portion 46 and the fitting hole portion 48 are tightly fitted or intermediately fitted. The outer peripheral surface of the flange portion 34 has serrations 50 over the entire circumference and entire length.
Is formed, the cross-sectional shape of the flange portion 34 is non-circular.

As shown in FIG. 5, the ring member 16 has a ring shape made of steel, and an inner peripheral surface thereof is formed with serration holes 54 over the entire length and the entire circumference. The serration holes 54 are the serrations 5 of the flange portion 34.
The diameter of the cylinder contacting the tops of the teeth forming the serration holes 54 is smaller than the outer diameter of the boss portion 20 of the main body member 10 by being formed to have a size capable of being fitted in a non-rotatable state by a value not less than the backlash. The size is made slightly smaller so that the boss 20 can be tightly fitted. As shown in an enlarged manner in FIG. 3, at one end of the serration hole 54, the tops of the teeth of the serration hole 54 are cut into the outer peripheral surface of the boss portion 20 which is relatively softer than the steel ring member 16. As a result, relative rotation of the ring member 16 with respect to the main body member 10 is favorably prevented. Further, the other end of the serration hole 54 has the serration 5 of the flange portion 34.
It is fitted so as to be substantially non-rotatable with 0.

Assembly of the shaft member 30 and the ring member 16 to the main body member 10 will be described. The male screw portion 32 of the shaft member 30 is inserted into the female screw hole 24 of the main body member 10, and the end surface 56 of the flange portion 34 on the fitting portion 46 side is the seat surface 2 of the main body member 10.
It is screwed until it sits on 2. In the middle, the fitting part 46
Is tightly fitted into the fitting hole portion 48 or intermediately fitted, so that the rotation resistance of the shaft member 30 is increased, but since the tool is engaged with the tool engagement portion 40 and a large rotation torque is applied, the fitting is performed. The fitting between the mating portion 46 and the fitting hole portion 48 progresses, and the flange portion 34 is eventually seated on the seat surface 22. In that state, the ring member 16 is axially inserted from the support shaft 14 side in a phase that allows the serration 50 to be fitted, and the serration hole 54 is fitted to the serration 50 of the flange portion 34. Then, the ring member 16 is moved to the main body member 10 side using a press-fitting machine, so that one axial end of the ring member 16 is tightly fitted to the boss portion 20 of the main body member 10. This completes the assembly of the main body member 10, the shaft member 30, and the ring member 16.

After that, the bush 12 is assembled to the support shaft 14. First, the bush 12 is fitted to the support shaft 14, and the nut 60 is tightened into the male screw portion 38 of the support shaft 14, so that the bush 12 cannot rotate relative to the support shaft 14 and the main body member 10 and is axially opposed. It is held immovable.

According to this embodiment, as described in the section [Problems to be solved by the invention, means for solving the problems and effects], the looseness between the male screw portion 32 and the female screw hole 24 is
The flange portion 34 and the boss portion 20 and the ring member 16 are fitted to each other, so that they can be reliably prevented. As described above, the ring member 16 can be assembled easily and inexpensively by the press-fitting machine with the shaft member 30 attached to the main body member 10. The body member 10 is made of an aluminum alloy in order to reduce the weight, but the ring member 16 made of steel having higher strength and hardness than the aluminum alloy is tightly fitted to the outer peripheral surface of the boss portion 20 so that the boss portion is 20 is reinforced from the outer peripheral side. Particularly, in the present embodiment, the fitting hole portion 4
The inner peripheral surface of 8 is tightly or intermediately fitted to the outer peripheral surface of the fitting portion 46, and the boss portion 20 is further strongly tightened to the inner peripheral side by the ring member 16, so that the boss portion 20 and the fitting portion 46 are Is firmly fixed.

As described above, it is desirable that the inner peripheral surface of the fitting hole portion 48 and the outer peripheral surface of the fitting portion 46 be a tight fit or an intermediate fit before the tight fit of the ring member 16. Not essential. Even when the fitting hole portion 48 and the fitting portion 46 are loosely fitted, it is easy to make the gap smaller than the gap between the male screw portion 32 and the female screw hole 24. The amount of relative movement can be reduced. In addition, the shaft member 30
Is tightened until the flange portion 34 is seated on the seat surface 22, and this tightening prevents relative movement of the shaft member 30 with respect to the main body member 10. Therefore, the inner peripheral surface of the fitting hole portion 48 and the fitting portion It is not essential to prevent relative movement of the shaft member 30 with respect to the main body member 10 by tight fitting or intermediate fitting with the outer peripheral surface of 46.

Although the embodiments of the present invention have been described in detail above, this is merely an example. INDUSTRIAL APPLICABILITY The present invention is applicable to securely fix an arm other than the L-shaped lower arm of a suspension device, or a steel shaft member other than a shaft-equipped member and a main body member made of an aluminum alloy. Problems to be Solved by the Invention, Means for Solving Problems, and Effects], and various modifications and improvements can be made based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a plan view showing an L-shaped lower arm, which is a type of arm of a suspension device as a shafted member according to an embodiment of the present invention.

FIG. 2 is a front sectional view showing a main body member, a shaft member, and a ring member that form the arm.

FIG. 3 is an enlarged view of part A of FIG.

FIG. 4 is a front view showing a shaft member of the arm.

FIG. 5 is a perspective view showing a ring member of the arm.

[Explanation of symbols]

10: Body member 12: Bush 14: Support shaft
16: Ring member 20: Boss part 22: Seating surface 24: Female screw hole 3
0: Shaft member 32: Male screw part 34: Flange part
38: Male screw part 40: Tool engaging part 46: Fitting part 48: Fitting hole part 50: Serration 5
4: Serration hole

Claims (5)

[Claims] 1. A boss portion made of an aluminum alloy,
A main body member having a seat surface formed at the tip of the boss portion and a female screw hole formed at a right angle to the seat surface; a male screw portion made of steel and capable of being screwed into the female screw hole; A shaft member having a flange portion that can be seated on a surface and has a non-circular cross-sectional shape, and a shaft portion that extends to the side opposite to the male screw portion with respect to the flange portion; And a ring member that is fitted into the female screw hole until the flange portion is seated on the seat surface, is fitted in a relatively non-rotatable manner with the flange portion, and is fitted tightly with the boss portion. A member with a shaft, comprising: 2. The shafted member according to claim 1, wherein the flange portion has a non-circular cross-sectional shape by forming serrations on the outer peripheral surface of the flange portion. 3. The shaft member according to claim 1, wherein a serration hole is formed over the entire length of the ring member, and a part of the serration hole is tightly fitted on the outer peripheral surface of the boss portion. 4. A fitting portion having a circular cross-sectional shape is provided between the male screw portion and the flange portion,
The shaft-equipped member according to any one of claims 1 to 3, wherein a fitting hole portion that is fitted into the fitting portion is provided between the female screw hole of the main body member and the seat surface. 5. The shafted member according to claim 1, wherein the main body member is a main body member of an arm of a suspension device, and the shaft member is a support shaft of a bush.