JPH0485171A - Core for steering wheel - Google Patents

Abstract

PURPOSE:To reduce working manhour, energy and cost by forming a boss body from a steel pipe as making it into almost uniform wall thickness over the full length, and setting up each of flange parts, flexibly projecting aslant in the radial direction, at both vertical ends. CONSTITUTION:A boss body 11 is formed out of a steel pipe, and a small diametral part 12, a taper part 13, flange parts 14, 15 and plural projections (knurling) 17 are all formed at one time press working (stamping). When the formed boss body 11 is set to a die casting forming die 30, these flange parts 14, 15 come to contact flexibly with a die surface of the forming die 30 in consequence, so trimming for die cast forming material is easily carried out, thus any possible flow of the die cast material into an inner circumferential side of the boss body 11 is prevented. As for whirl stopping to a die cast part of the boss body 11, it is performed by the small diametral part 12 or knurling 17, and antislipping-off is performed by the flange parts 14, 15 and the taper part 13.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a core metal for a steering wheel, and more specifically, a boss portion includes a substantially cylindrical boss body connected to a steering shaft, and a boss body of the boss body. The present invention relates to a core metal for a steering wheel in which a die-cast part formed from a die-cast metal is disposed around the core metal.

<Prior Art> Conventionally, core metals for steering wheels in which a die-cast part made of die-cast metal is disposed around a boss body connected to a steering shaft are disclosed in Japanese Patent Publication No. 63-82872 and Japanese Patent Application Laid-Open No. 1-215666, etc. As shown in FIG.
mm, wall thickness approximately 5.5 mm).
It was formed by providing a thick swollen portion 2 at the intermediate portion and a tapered portion 3 that widens upward at the lower portion on the inner circumferential side.

By setting the boss body 1 formed in this manner in a predetermined die-casting mold and forming a die-cast part 5 made of die-cast metal around the boss body 1, a core for a steering wheel is formed as shown in FIG. Gold WO can be produced.

Incidentally, a serration portion 4 for connecting to the steering shaft is formed on the upper inner circumferential side of the boss body 1, and this serration portion 4 is formed by cutting after molding the die-cast portion 5. be done.

Further, the bulging portion 2 is formed in a non-circular hexagonal column shape so that the boss body 1 does not rotate with respect to the die-casting portion 5, and furthermore, the bulging portion 2 is formed in the shape of a non-circular hexagonal column so that the boss body 1 does not come off from the die-casting portion 5. It is formed so that it bulges out by mm.

Furthermore, the serration portion 5 on the inner peripheral side of the boss body 1
The lower taper portion 3 is formed to correspond to the taper portion of the steering shaft, and is formed to increase the strength of connection with the steering shaft.

<Problems to be Solved by the Invention> However, as mentioned above, the boss body 1 in the conventional steering wheel core metal WO is 3 to 5 times smaller than other parts.
The bulging portion 2 having a thickness of about mm is formed by swaging. Therefore, the swaging process is a process in which the material is within the thickness and forms thicker parts.
- It is difficult to process in one step, for example, it has to be processed in stages in four steps, and the steering wheel core metal WO
This increases processing costs by increasing the number of processing steps and processing energy when manufacturing.

Here, by applying the technology described in JP-A No. 61-46328, a steel pipe is processed using a combination of bulge forming and press working to form a cylindrical part to be connected to the steering shaft, and a cylindrical part to be connected to the steering shaft. It is conceivable to form a boss main body having a shape including a plate portion projecting in a non-circular shape on the upper portion of the boss body.

However, with the boss body formed in this way, during die-casting to form a die-cast part around the boss body, the die-casting material is not cut off at the plate part at the top of the cylindrical part because the plate part has a wide planar shape. , and the die-casting material tends to flow into the inner circumference of the cylindrical part. If the die-casting material flows to the inner circumference of the cylindrical part, it will be necessary to remove it.
It takes a lot of time to manufacture core metal for steering wheels.

The present invention solves the above-mentioned problems, and makes it possible to easily manufacture a boss body, and prevent die-casting material from flowing into the inner circumferential side of the boss body connected to the steering shaft during die-casting. An object of the present invention is to provide a core metal for a steering wheel, which can be molded by molding, reduce deburring work after molding, and can be manufactured with reduced processing man-hours, processing energy, and processing costs.

Means for Solving the Problems> A core metal for a steering wheel according to the present invention includes a substantially cylindrical boss main body connected to a steering shaft in a boss part, and a core metal made of die-cast metal arranged around the boss main body. A cored bar for a steering wheel, in which the boss body is formed from a steel pipe with a substantially uniform wall thickness over the entire length, and a small diameter part disposed at an upper part of the intermediate part. , a tapered part disposed at the lower part of the small diameter part and expanding downward, and a collar part disposed at both the upper and lower ends and projecting at a radial inclination so as to be flexible, and the inside of the small diameter part The steering wheel is characterized by being configured to include a serration portion disposed on the circumferential side and fitted to the steering shaft, and a plurality of convex portions disposed on the outer circumferential side of the small diameter portion or tapered portion. .

Note that the slope of the flange includes not only the case where the cross section is formed into a flat plate shape but also the case where the cross section is formed into an arc shape.

<Operations and Effects of the Invention> In the core metal for a steering wheel according to the present invention, since the boss body is formed from a steel pipe with a substantially uniform wall thickness over the entire length, the small diameter portion,
The tapered portion, the collar portions at the upper and lower ends, and the plurality of convex portions can be easily formed.

In addition, when the formed boss body is set in a die-casting mold and the mold is closed, the flanges at the upper and lower ends of the boss body, which can be bent and protrude in a radial direction, are aligned with the mold surface of the mold. This bends and makes contact, making it easy to cut the die-casting material and preventing the die-casting material from flowing into the inner circumferential side of the boss body.

Furthermore, since the flange flexes, even if there are variations in the dimensions of the die-casting mold or the boss body itself, the flange flexes.
It is possible to absorb these variations and form a die-cast part in a predetermined area.

Note that the serrations on the inner peripheral side of the boss body are formed by cutting after die-casting.

In addition, the boss body is prevented from rotating against the die-cast part by a plurality of convex parts arranged on the outer circumferential side of the small diameter part or the tapered part, and the boss body from the die-cast part is prevented from being pulled out by the flanges at the upper and lower ends or by the taper part. This will be carried out by the department.

Therefore, with the core metal for a steering wheel according to the present invention, the boss body can be manufactured easily, and the die-casting material can be prevented from flowing into the inner peripheral side of the boss body that is connected to the steering shaft during die-casting. It can be molded, the deburring work after molding can be reduced, and the number of processing steps, processing energy, and processing costs can be reduced.

<Example> Hereinafter, one embodiment of the present invention will be described based on the drawings.

As shown in FIG. 2, the steering wheel core metal W1 of the embodiment includes a ring portion R, a boss portion B at the center of the ring portion R, and four spokes connecting the ring portion R and the boss portion B. It is composed of a part S and a part S.

The ring portion R is formed into an annular shape from a steel pipe.

The boss portion B includes a boss body 11 connected to a steering shaft (not shown) and a die-cast portion 18 disposed around the boss body 11.

In the case of the embodiment, this die-cast part 18 is a spoke part S
The boss body 1 is made of die-cast metal made of light alloy such as aluminum or magnesium.
It extends from the periphery of 1 to wrap around the ring portion R.

The boss body 11 is formed by pressing a thin steel pipe 10 (see Fig. 4) with a wall thickness of approximately 0.5 to 3 mm at predetermined portions, and has a substantially uniform wall thickness over its entire length. It is said that

As shown in FIGS. 1 and 3, the boss main body 11 has a small diameter part 12 arranged at the upper part of the intermediate part, a tapered part 13 arranged at the lower part of the small diameter part 12 and widening downward, and an upper and lower part. It is provided with collar portions 14 and 15 that are arranged at both ends and are flexible and project obliquely in the radial direction.

In the case of the embodiment, the flanges 14 and 15 are formed to widen toward the end side at an angle α of 30 to 60 degrees from the axial direction of the boss body 11, and the inner corner portions thereof 14a-
15a are located at the upper and lower ends of the boss body 11, respectively, and on the outside of the outer peripheral surface of the small diameter portion 12 or the tapered portion 13, respectively.

Further, a serration portion 16 that fits into a steering shaft (not shown) is formed on the inner circumferential side of the small diameter portion 12, and a flat knurling (the height of the unevenness is approximately 1 mm) is formed on the outer circumferential side of the small diameter portion 12. A plurality of convex portions 17 are formed.

The die-cast portion 18 of the boss body 11 of the embodiment is prevented from rotating by a plurality of convex portions 17 disposed on the outer peripheral side of the small diameter portion 12.
The flange portions 14 and 15 and the tapered portion 13 at the upper and lower ends are used to prevent removal.

Next, manufacturing of this core metal W1 for a steering wheel will be explained.

First, the boss body 11 is manufactured. To manufacture the boss body 11, as shown in FIG.
Processed surface 2 that is arranged on the outer circumferential side of 0 and can form a convex portion 17
A half or three-split die 22 with 2a,
It uses 20/21 punches and 2 dice.
2 are formed with concave portions and convex portions (numerals omitted in the figures) that allow each part of the boss body 11 to be processed into a predetermined shape. Note that the serration portion 1 formed on the inner peripheral side of the small diameter portion 12
These punches 20 and 21 are not formed during this pressing process but are formed by cutting on the inner circumferential surface of the small diameter portion 12 of the boss body 11 after forming the die-cast portion 18.
The boss body 11 is manufactured by removing the serration portion 16 from the steel pipe 10 by press working using a die 22.

After that, this boss body 1 is placed in a predetermined die-casting mold.
1 and the ring part R are set, and the die-cast part 18 is formed by clamping the mold. At this time, as shown in FIG. 5, the flanges 14 and 15 at the upper and lower ends of the boss body 11 are bent, and the corners 14a and 15a are bent into the split mold 31 and the corner parts 14a and 15a of the die-casting mold 30.
32, the die-casting material M can be well cut, and the die-casting material M can be prevented from flowing into the inner peripheral side of the boss body 11. Further, the corner portions 14a and 15a are formed in the small diameter portion 12 or the tapered portion 13.
They are located on the outside of the outer peripheral surface of the mold and can self-seal during molding, allowing for good layering and crisp cutting. Note that 33 is a set bin for the boss body 11.

After the die-cast part 18 is formed, the mold is opened and released, and the serration part 16 is formed by cutting on the inner peripheral surface of the small diameter part 12 of the boss body 11. W1 can be manufactured.

In the steering wheel core metal W1 manufactured in this manner, the boss body 11 is formed from a steel tube 10 with a substantially uniform wall thickness over the entire length, so that the small diameter portion 12, the tapered portion 13, Flange section 14 at the upper and lower ends
15 and a plurality of convex portions 17 can be easily formed.

Further, the formed boss body 11 is placed into a die casting mold 30.
When the mold is closed, the flanges 14 and 15 at the upper and lower ends of the boss body 11 that protrude in a radial direction are bent, and the corners 14a and 15a are pressed against the mold surfaces of the split molds 31 and 32. This makes it possible to easily cut the die-casting material M and prevent the die-casting material from flowing into the inner circumferential side of the boss body 11, which is similar to the operation and effect of the invention described above. It has a great effect.

In addition, in the embodiment, the flange portion 14.1 of the boss body 11
5 with a flat plate-like cross-sectional shape and an inclined flange 1.
Connect the inner corners 14a and 15a of 4 and 15 to the boss body 11.
It shows what is to be placed at the top and bottom positions of. However, these flanges 14 and 15 only need to be inclined and protrude in the radial direction of the boss body 11 so as to bend and come into contact with the mold surface of the die-casting mold 30. Therefore, the boss shown in FIG. Like the main body 41, the collar parts 44 and 45 have a cross-sectional shape of
The radius on the inner circumferential surface side is approximately 1/2 times larger than the thickness of the boss body 41.
It may be made into a four-arc shape, or may be inclined in a circular arc shape.

In addition, in the embodiment, in order to prevent the boss body 11 from rotating with respect to the die-casting part 18, a convex part 1 is provided on the outer peripheral side of the small diameter part 12.
7 is shown, but the boss body 4 shown in FIG.
1, a plurality of convex portions 47 may be formed to partially protrude on the outer circumferential side of the tapered portion 43.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a boss portion of a steering wheel core metal according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II in FIG. Figure 3 is a front view of the boss body used in the same example, Figure 4 is an explanatory diagram showing the processing of the boss body used in the same example, and Figure 5 is a diagram showing the molding of the die-cast part of the same example. Figure 6 is a partially cutaway front view of a boss body used in another embodiment; Figure 7 is a sectional view of the boss portion of a conventional steering wheel core; Figure 8 is a conventional FIG. 3 is an explanatory view showing processing of the boss body of the steering wheel core metal of FIG. 11, 41... Boss body, 12... Small diameter part, 13, 43... Taper part, 14, 15, 44, 45... Flange part, 16... Serration part, 17, 47... - Convex portion, 18...Die-casting part, B...Boss part, Wl...Core metal for steering wheel. Diagram diagram diagram diagram diagram?

Claims (1)

[Scope of Claims] A steering wheel in which a boss portion is provided with a substantially cylindrical boss body connected to a steering shaft, and a die-cast portion disposed around the boss body and formed from die-cast metal. The boss body is formed from a steel pipe with a substantially uniform wall thickness over the entire length, and includes a small diameter portion disposed at the upper part of the intermediate portion, and a small diameter portion disposed at the bottom of the small diameter portion and extending downwardly. A tapered portion that widens towards the front, and a collar portion that is disposed at both the upper and lower ends and protrudes while being flexible and inclined in the radial direction, and is disposed on the inner circumferential side of the small diameter portion and is fitted to the steering shaft. A core metal for a steering wheel, comprising: a serration portion that fits together; and a plurality of convex portions disposed on the outer peripheral side of the small diameter portion or the tapered portion.