JPH035250B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a method of manufacturing a steering wheel.

(Prior Art) Conventionally, a steering wheel core metal having a structure including a ring portion core metal formed of a round pipe and a spoke portion core metal joined to the ring portion core metal is well known.

Then, an exterior material made of a soft synthetic resin such as polyurethane foam or polyvinyl chloride is coated on the outer circumferential surface of the core bar with an adhesive, and this exterior material constitutes the grip part of the ring core bar. Steering wheels are also well known.

However, in the above-mentioned steering wheel, in the ring core made of a round pipe, the adhesive layer between the exterior material and the ring core tends to peel off due to twisting, and this causes the exterior material to peel off due to twisting. may rotate or rotate.

Therefore, various attempts have been made to prevent rotation and rotation of the exterior material of the steering wheel. do)
There is one that uses a steering wheel core metal with a non-circular shape. This core metal is manufactured by the following procedure.

First, a metal round pipe is drawn using a die having a rectangular opening to produce a material for manufacturing a ring core metal having a rectangular cross-sectional shape.

Next, as shown in FIG. 4, the material is bent into a ring shape to form a ring-shaped object Q, and its both end surfaces 2
5 and 26 are welded to manufacture the ring part core metal. Then, one end of the spoke part core metal is welded to the ring part core metal, and a boss part is fixed to the other end of the spoke part core metal, thereby producing a steering wheel core metal.

Then, a steering wheel is manufactured by covering the outer peripheral surface of this steering wheel core metal with a soft synthetic resin exterior material.

(Problem to be Solved by the Invention) However, when a steering wheel is manufactured using the above procedure, when bending a material with a square cross section into a ring-shaped object Q in the manufacturing process of the ring core metal, the The materials are twisted, making it difficult to butt the two end faces together, and if the two end faces are forcibly butted together and welded, the finishing accuracy will deteriorate accordingly.

Furthermore, as shown in FIG.
Even if you try to make the ends of the spoke part core metal 22 abut against each other exactly, the ring part core metal 2
If there is a twisted portion in 1, a gap 24 will be created between the end of the spoke part core metal 22 and the ring part core metal 21, as shown in FIG. This leads to the problem of weakening the welding strength when welding the above-mentioned problem.

Further, the method of drawing out a round pipe has a problem in that the manufacturing cost is high, and a pipe with a square cross section is relatively expensive as a material for manufacturing a ring portion core metal.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a steering wheel, which eliminates the problems in the manufacturing process of the slearing wheel core metal and further prevents rotation and rotation of the exterior material.

Structure of the Invention (Means for Solving Problems) The present invention has a steering wheel core metal including a boss part, a ring part core metal, and a spoke part core metal that joins the boss part and the ring part core metal. , in a method for manufacturing a steering wheel in which at least the outer peripheral surface of a ring portion core metal is coated with a soft synthetic resin exterior material, in the process of manufacturing the ring portion core metal, a metal round pipe is bent into a ring shape. a process of forming a ring-shaped object by joining both ends thereof to form a single ring-shaped object; and a process of rotating and rotating the ring-shaped object with its both ends joined after being coated with the exterior material. By adopting a method of press-forming the cross-section into a square or almost square cross-section to the extent that it can be prevented, and covering the outer circumferential surface of the pressed ring core with a soft synthetic resin exterior material. Then,
This is an attempt to solve the above-mentioned problems.

(Function) In the ring part core metal manufacturing process, a round pipe is bent to form a ring-shaped object, both ends of which are joined to form a single ring-shaped object, and then the cross section of the ring-shaped object is In order to prevent rotation and rotation of the exterior material, the ring core metal is manufactured by pressing into a square or almost square shape, so the ring-shaped object may become kinked during the process of forming the ring-shaped object from a round pipe. However, since the ring-shaped object is made of a round pipe, the twist is not apparent, and
It becomes easy to butt both end faces. Furthermore, in the subsequent press working process, the ring core has no free-moving ends and is shaped like a single ring, so there is no chance of twisting the ring core, and the ring core has a rectangular cross section or A substantially rectangular ring core can be easily produced. Since a soft synthetic resin exterior material is coated on the outer peripheral surface of the ring core metal having a square or nearly square cross section, rotation and rotation of this exterior material with respect to the ring core metal can be prevented. .

(Example) An example embodying the method of the present invention will be described based on FIGS. 1 to 3.

First, a round steel pipe with an outer diameter of 15.9 mm and a wall thickness of 1.6 mm is processed into a ring shape to create a ring with an outer diameter of 37 cm. Then, both ends of the ring-shaped object are joined by welding. The means are the same as known means.

Next, as shown in FIG. 2, the ring-shaped object P is placed on a lower mold 5 having an inner surface 7 with two orthogonal surfaces. Then, an upper mold 6 which is provided opposite to the lower mold 5 and has an inner surface 8 similar to that of the lower mold 5 is placed on the ring-shaped object P.
A part of the mold is sandwiched between two molds 5 and 6.

Then, as shown in FIG. 3, a pressing force is applied to the upper mold 6 to press-form the ring-shaped object P, thereby forming the ring-portion core metal 1 having a square cross section and a hollow shape.

The ring part core metal 1 obtained in this way has a first
As shown in the figure, one end of the spoke part core metal 2 is joined by welding, and a boss part 4 is attached to the other end of the spoke part core metal 2, which is arranged facing approximately the center of the ring part core metal 1. to weld.

Finally, the steering wheel is completed by covering the steering wheel core metal 3 with a soft synthetic resin exterior material (not shown) using a method similar to the conventional method.

According to this method, there is no chance that the ring core metal 1 will be twisted.

This is because the ring-shaped object P is formed from a round pipe, and then the cross section is pressed into a square or nearly square shape to form the ring part core metal 1 in order to prevent the rotation and rotation of the exterior material. Even if the ring-shaped object P is kinked during the process of forming the pipe, it is possible to join the ring-shaped object P by butting both end surfaces together, even if the ring-shaped object P is kinked, and if the two end surfaces are welded together while the kink remains, the kink will be removed in appearance. not noticeable,
Therefore, there is no chance of twisting the ring core metal in the subsequent press working process.

Therefore, the difficulty of butting operation (positioning) of both end faces when bending a hollow pipe having a square cross section is eliminated, welding becomes easy, and the joining finish at the joint in the ring core metal 1 is eliminated. Improves accuracy.

Moreover, according to this method, the ring-shaped object P is pressed so as to have a square cross section by simple press forming, so the ring core metal 1 having a square cross section can be manufactured at low cost. can.

Further, it is easy to weld the ends of the spoke part core metal 2 to the ring part core metal 1 having a square cross section by tightly butting them together. Furthermore, since the outer circumferential surface of the ring core metal 1 having a square cross section is coated with a soft synthetic resin exterior material, rotation and rotation of this exterior material with respect to the ring core metal 1 can be prevented. .

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can also be implemented, for example, in the following embodiments.

(1) The cross-sectional shape of the ring core metal 1 is such that the outer material rotates and
Any shape may be used as long as it does not rotate, for example, a gourd shape may be used. However, the anti-rotation ability of the exterior material,
Strength of ring core metal 1, ease of press processing,
Considering various factors such as the ease with which the spoke part core metals 1 can be butted together, the most preferable cross-sectional shape is a square or a nearly square. Further, as in the conventional case, an adhesive may be interposed between the ring core metal 1 and the exterior material, and in that case, the rotation and rotation of the exterior material can be more firmly prevented.

(2) Process a metal round pipe into a ring shape, join the ends by welding, attach the boss part 4 to the spoke part core metal 2 by welding, etc., and cut a part of the steering wheel core metal 1 in cross section. It may be pressed into a square or approximately square shape.

(3) A portion of the ring core metal 1 in its circumferential direction, for example, a portion where the spoke core metal 2 is not joined, may be pressed into a non-circular shape, but the entire ring portion core metal 1 may be pressed in the same manner. good.

(4) Any means may be used to press the cross section of the ring core metal 1 into a non-circular shape as long as it can press the ring core metal 1 into a non-circular shape while keeping it hollow. The mold used for pressing may be a continuous mold along the circumferential direction of the ring core 1, or a split mold split radially from the center of the ring core 1. It can be arbitrarily determined by considering the cross-sectional shape of the gold 1, etc.

(5) The spoke part core metal 2 only needs to be made of a metal material that can be welded to the ring part core metal 1, for example,
The cross-sectional shape can be arbitrarily selected according to need, such as using a plate or having only the end section shaped like a fan. The number of spoke portion core metals 2 and the attachment locations can also be arbitrarily selected.

Effects of the Invention In the manufacturing method of the present invention, in the process of manufacturing the ring part core metal, a metal round pipe is made into a ring shape, both ends are joined to form a single ring-shaped object, and the cross section of the pipe is made into a ring-shaped object. Since the ring core metal is press-formed into a square or nearly square shape so that it does not rotate or rotate, there is no chance for the ring core metal to twist. Finishing accuracy is improved, and the end portions of the spoke core metal are more accurately butted against the ring core metal, which in turn increases the welding strength between the ring core metal and the spoke core metal.

In addition, unlike conventional methods, it is possible to manufacture a ring portion core metal with a square or nearly square cross section at a low cost, and in turn, it is possible to manufacture a steering wheel that prevents rotation and rotation of the exterior material at a low cost. .

[Brief explanation of the drawing]

Figure 1 is a front view of the steering wheel core metal.
Figure 2 is a sectional view showing a ring-shaped object sandwiched between molds to process it into a non-circular shape, Figure 3 is a sectional view showing a ring-shaped object processed into a non-circular shape, and Figure 4 is a sectional view showing the conventional method. FIG. 5 is a perspective view of the manufactured ring-shaped product; FIG. 5 is a cross-sectional view showing a state in which the ends of the spoke core metal are normally butted against the ring core metal; FIG.
The figure is a cross-sectional view showing a state in which the ends of the spoke part core metal are inclined and butted against the ring part core metal. Ring part core metal 1, spoke part core metal 2, steering wheel core metal 3, ring-shaped object P.

Claims (1)

[Scope of Claims] 1. A steering wheel core metal consisting of a boss portion 4, a ring portion core metal 1, and a spoke portion core metal 2 that joins the boss portion 4 and the ring portion core metal 1, at least the ring portion core metal 1. In a method for manufacturing a steering wheel in which a soft synthetic resin exterior material is coated and molded on the outer peripheral surface of metal 1, in the process of manufacturing the ring portion core metal 1, a metal round pipe is bent into a ring shape to form the ring. a process of forming a ring-shaped object by joining both ends of the ring-shaped object, and a range in which the exterior material can prevent rotation and rotation of the ring-shaped object with its both ends joined after being coated and molded. manufacturing a steering wheel, which comprises a step of press working into a square or nearly square cross section, and covering the outer peripheral surface of the pressed ring core metal 1 with an exterior material made of soft synthetic resin. Method.