JPS6094484A - Manufacture of steering wheel - Google Patents

Abstract

PURPOSE:To manufacture a steering wheel resistant to the circumferential displacement of the rim part, by forming a covering layer composed of a flexible synthetic resin on an iron core interposing a crosslinkable adhesive layer containing a thermally activating functional group therebetween, and heating the iron core by induction heating to effect the curing of the adhesive layer. CONSTITUTION:The covering layer 2 is formed on the iron core of the rim usually by the injection molding of a crosslinkable adhesive having thermally activating functional group (e.g. hydroxyl group) in the state of prepolymer (e.g. thermosetting acrylic resin, etc.). The covered core is set in a high-frequency heating apparatus, and the surface of the iron core of the rim is heated instantaneously to effect the crosslinking of the adhesive layer 3 and obtain the objective steering wheel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a steering wheel (hereinafter abbreviated as rS/WJ) comprising a rim portion in which a coating layer made of soft synthetic resin is formed on an iron core via an adhesive layer. Relating to a method of manufacturing.

Here, the soft synthetic resin will be explained using soft polyvinyl chloride (PVC) as an example, but the invention is not limited to this, and the same can be applied to other resins such as soft polyurethane. .

Recently, from the viewpoint of reducing the weight of S/W, hollow cores are becoming popular instead of the conventional solid cores.

However, the sliding (turning) of the coating layer in the circumferential direction with respect to the iron core
In order to prevent this, it is difficult to make a hollow core with an irregular shape (hole-shaped cross section: see Figure 1) like the conventional solid core l, which is at most an elliptical or rectangular cross section (see Figure 2). Coupled with the fact that the covering layer is soft, most of the adhesive layer has to be used. However, the room-temperature-curing chloroprene-based or thermoplastic vinyl polymer-based adhesives normally used to bond the conventional irregularly shaped solid core and the covering layer 2 do not have sufficient adhesive strength in the circumferential direction of the covering layer. It was difficult to obtain sufficient □ to prevent slipping.

In view of the above, an object of the present invention is to provide a method for manufacturing S/W that can form an adhesive layer that is effective in preventing abrasion in the circumferential direction of a rim portion coating layer.

The S/W manufacturing method of the present invention includes forming an adhesive layer on the rim core using a crosslinked adhesive, and after forming a rim covering layer, the adhesive layer is heated by induction heating the rim core. It is characterized by curing.

Examples of cross-linked adhesives used in this invention include those containing thermosetting acrylic resins, polyurethane, epoxy resins, phenol resins, melamine resins, etc. as polymer components, but thermosetting acrylic resins and polyurethanes are particularly preferred. . Note that these adhesives are C in the prepolymer state.
It has a structure that is easily crosslinked as it has thermally active functional groups such as 0OH group, hydroxyl group, NGO group, epoxide, and NH2 group.

The rim portion coating layer is usually formed by injection molding.・Immediately after forming the rim coating layer, induction heating is carried out by setting a high-frequency heating device to instantaneously heat the rim core surface to approximately 150°C or higher (preferably 200 to 250°C) and maintaining it for 10 to 60 seconds. Crosslink the adhesive layer. At this time, the induction heating conditions are, for example, a frequency of 100K)! 2. Output 1 OKIll tossle.

In this way, an adhesive layer is formed between the core and the coating layer, which has a strength that can effectively prevent the coating layer from rubbing in the circumferential direction.

Next, the present invention will be explained in more detail based on examples.

In Examples 1 and 2, adhesives A and B shown in Table 1 were applied to the iron core 1 of a round pipe as shown in Fig. 1 by tapping, and after drying (15 minutes at room temperature), a PVC material with the following composition was applied. Immediately set the molded product in a high-frequency generator and generate 45 kW at a frequency of 10QKH2 and an output of 10Kw.
The adhesive layer 3 was cured by induction heating for a second. The temperature at which the surface of the iron core was raised was 200''C in all cases.

<PVC blend> Polymer 100 parts Plasticizer 100 parts Stabilizer 3 parts Filler 50 parts Each S/W produced in this way was tested for each of the following items. The results are shown in Table 2.
It can be seen that the adhesive strength between the coating layer and the iron core at the rim portion of W is sufficient to prevent the i-layer from rubbing in both room temperature and high temperature (60° C.) atmospheres. In addition, the conventional example (Fig. 1)
The reference example (FIG. 2) was manufactured in the same manner as in the example except that adhesive C shown in Table 1 was used and induction heating was not performed.

Test Items> (1) Product Torsion Test When the ring part of the S/W was grasped and twisted by hand, it was determined whether there was any rubbing movement in the circumferential direction of the coating layer.

O...no sliding movement, ×...sliding movement (2) Cut the ring part of the torsion torque S/W into a 50+ui length with the iron core protruding about 10 mm to one side, and use a torque wrench on the iron core. was connected and twisted, and the torque was measured when separation occurred between the core and the coating layer.

According to the method for manufacturing 57W of this invention, as described above,
The coating layer strongly adheres to the rim core by induction heating of a cross-linked adhesive with thermally active functional groups, and the circumferential rubbing of the rim coating layer against the rim core is effective both at room temperature and in high-temperature atmospheres. is prevented. Therefore, when the iron core is solid, it is not necessary to make it into an irregular shape as in the conventional case, and even when the iron core is hollow, it is possible to reliably manufacture a good product without the possibility of scratching of the rim covering part.

Table 1 Table 2

[Brief explanation of drawings]

The illustrated examples each show a cross section of the ring portion of the S/W, with FIG. 1 showing a conventional example, FIG. 2 a reference example, and FIG. 3 an example. ■... Iron core, 2... Covering layer, 3... Adhesive layer. Patent application Toyoda Gosei Co., Ltd. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] When manufacturing a steering wheel having a rim portion in which a coating layer made of a soft synthetic resin is formed on an iron core via an adhesive layer, the adhesive layer has a thermally activated functional group. A method for manufacturing a steering wheel, comprising forming the steering wheel using a cross-linked adhesive, and curing the adhesive layer by induction heating the iron core after forming the coating layer.