JPS6330603Y2 - - Google Patents

Description

[Detailed description of the invention] This invention provides a hollow part in the shape of one of quadrilateral, pentagonal, hexagonal, heptagonal, and octagonal inside a hollow pipe, and each corner of this inner polygon This relates to a rim core metal for a steering wheel, which is characterized by a protrusion provided on the outside of a portion corresponding to the rim of the steering wheel.

Conventional steering wheel rim cores use circular hollow pipes, which are lightweight due to their hollowness, and have the characteristic of having high resistance to bending. However, the synthetic resin coating layer that constitutes the grip part spins around the rim core. As an improved product that eliminates this drawback, for example, as shown in Fig. 6 or described in JP-A-56-30810, there is a steering wheel rim core 15 in which small ridges 13 are formed at the corners of a polygonal central steel material 11, and this conventional improved product is quite effective in preventing spinning. However, because it is solid, it is excessively heavy, and because the ridges are small in width and generally angular, it has the disadvantage that it is impossible to use straightening rolls to straighten out the twists and bends in the rim core material, and because of this, when a certain length of rim core material is bent into a ring shape by machine and one end of the rim core material is butted together and welded, the ridges and valleys of the rim core material will not match up, making it difficult to align the ridges, etc. In particular, when an automatic robot is used to bend the rim core material into a ring shape and weld the ends together to make the rim core material, there is a disadvantage that if the rim core material is left bent, automatic feeding cannot be performed, and the rim core material cannot be made by an automatic robot.

This invention eliminates these drawbacks of conventional steering wheel rim core metals, allows the material of the rim core metal to be straightened, and curves the straightened rim core metal material into a ring shape to straighten the edge of the rim core metal material. The purpose is to match the protrusions and protrusions of the parts, and the valleys.

Next, one embodiment of the steering wheel rim core metal of this invention will be described with reference to the drawings.

Example A hexagonal hollow part 2 is provided inside a hollow pipe 1. Projections 3 are provided in parallel to the longitudinal direction of the hollow pipe 1 on the outside of the hollow pipe 1 at locations opposite to the hexagonal corners thereof. The width of this protrusion 3 is made slightly larger than the width of the valley 4 between the protrusions 3, and the outer side surface 3' of this protrusion 3 is made slightly larger.
are each formed into a circumferential shape from the center point of the hollow pipe 1, and both side surfaces 3'' of the protrusion 3 are narrowed so as to be oriented approximately toward the center point of the hollow pipe 1.

To manufacture the rim core metal 5 of the steering wheel of this embodiment, first, as shown in FIGS. The material for the rim core metal 5 is made by pushing the pipe 6 through it.

The material of the rim core metal 5 thus produced is then cut to a predetermined length, and a large number of these are arranged horizontally in two stages, upper and lower, to form straightening rolls each having an inclination angle in a different direction. By passing between a pair of drum-shaped rolls, the twisting and bending of the material of the rim core metal 5 is corrected, and the material of the rim core metal 5 is brought into a substantially normal state, that is, with almost no twist and a substantially straight shape. . When the material of the rim core metal 5 is passed between these straightening rolls, the material of the rim core metal 5 is
The outer side surface 3' of the rim core bar 5 is made circular, and the width of the protrusion 3 is made slightly larger than the width of the valley.
Since the material is made closer to a perfect circle, it is easier to pass through the straightening rolls, and the material of the rim core 5 can be straightened more reliably without idling between the straightening rolls. .

Further, the straightened material of the rim core metal 5 is bent into a ring shape using an automatic robot and the ends are welded together, thereby forming protrusions 3, protrusions 3, and valleys 4 at the ends of the material of the rim core metal 5. A rim core metal 5 is made in which the and valley portions 4 are well matched.

As shown in the graph of Fig. 3, the results of a bending stress test performed on the rim core metal 5 of this example with a diameter of 11 mm are as follows. Since the bending stress is significantly higher than that of a rod, a steering wheel in which this type of rim core material is curved into a ring shape and welded as the rim core metal will not deform the rim part during operation. There is no risk of this occurring, and since the side surfaces 3'' on both sides of the protrusion 3 provided on the outside of the rim core 5 are oriented toward the center, a so-called undercut, the synthetic resin layer covering the outer periphery of the rim core 5 can be When provided, the synthetic resin layer has good bite and there is no risk that the synthetic resin coating layer will idle around the rim core metal.

In addition, in this embodiment, a rim core metal 5 was explained in which a hexagonal hollow part 2 was provided inside a hollow pipe, but according to the experimental results, a hexagonal hollow part was the best, and the second best after the hexagonal hollow part. A quadrangular or octagonal hollow part is the second best. Furthermore, a pentagonal or heptagonal hollow part is the third best. One of the reasons why a hexagonal shape is the best, and a quadrangular or octagonal hollow part is the second best is that when the material is passed through the straightening rolls arranged in two stages above and below, the vertical balance is good, and the straightening rolls do not spin idly. This is because shipping is easier. A triangular shape is unsuitable because it is too heavy and there are places where the outer circumferential surface does not come into contact with the upper and lower straightening rolls, making it difficult to feed. Further, those having hollow portions of more than nine sides are unsuitable because of their complicated structure.

Further, in this embodiment, a rim core bar in which the width of the protrusion 3 is slightly larger than the width of the valley portion 4 has been described, but the width of the protrusion may be approximately the same as the width of the valley portion.

Although the rim core metal of the steering wheel of this invention has protrusions and valleys on the outside, the material of the rim core metal can be straightened with a straightening roll, and the material of the rim core metal that has been straightened can be straightened. It is possible to obtain a high-quality rim core metal that is curved into a ring shape and has protrusions and protrusions at the ends and troughs and troughs.

Furthermore, the rim core metal of the steering wheel of this invention can straighten the rim core material as described above, so the rim core metal material that has been straightened and has almost no twist and is almost straight is used as the raw material and can be automatically processed. The rim core metal can be automatically created by a robot, and if a synthetic resin coating layer is provided around the outer periphery of the rim core metal, the synthetic resin coating layer can be formed because both sides of the protrusion are oriented toward the center. It has a good bite,
This has the effect that the synthetic resin coating layer does not idle around the rim core metal.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the product of the present invention, Fig. 2 is an enlarged end view taken along the line A-A in Fig. 1, and Fig. 3 is a diagram showing bending stress.
FIG. 4 is a front view of the die, FIG. 5 is a sectional view of the die and hollow pipe, and FIG. 6 is an enlarged end view of the conventional product. 1 is a hollow pipe, 2 is a hollow part, 3 is a protrusion, 4 is a valley part, and 5 is a rim core metal.

Claims (1)

[Scope of utility model registration request] Square, pentagon, hexagon, inside the hollow pipe.
A hollow part in the shape of one of heptagons and octagons is provided, and the width of the protrusion is equal to or less than the width of the valley part on the outside of the part corresponding to each corner of the inner polygon of the hollow pipe. The above-mentioned protrusions are provided in the longitudinal direction of the hollow pipe, and the outer side surfaces of the protrusions are each circumferential from the center point of the hollow pipe, and both side surfaces of the protrusions are approximately at the center point of the hollow pipe. A rim core metal for a steering wheel characterized by being formed in a shape oriented to.