JPH0413131B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing a steering wheel by forming a synthetic resin coating on the surface of a ring portion core metal of a steering wheel core metal. It is something.

(Prior Art and Problems to be Solved by the Invention) As shown in FIGS. 8 and 9, in a normal steering wheel 51, the ring portion core metal 52a of the steering wheel core metal 52 is coated. If the sheathing material 53 is made of a soft material such as soft polyvinyl chloride resin, the sheathing material 53 will move around the ring core bar 52a in the direction of the arrow X.
The steering wheel 51 rotates in the direction shown by , and the driver may lose his or her grip on the steering wheel 51 .

Therefore, in order to prevent the rotation of the sheathing material 53, a hardening adhesive is applied to the ring core bar 52a, and then the sheathing material 53 is formed around the ring core bar 52a. A technique for curing adhesives is known (Japanese Patent Laid-Open No. 60-94484).

Although this technique has shown some effectiveness, in the method described above, the surface of the adhesive is covered with the coating material 53, so it takes time to heat the adhesive, which only lengthens the manufacturing cycle of the steering wheel. Otherwise, the amount of heat necessary for the reaction of the curable adhesive may not be provided, and the adhesive performance of the adhesive may not be sufficient. Therefore, the steering wheel obtained by the conventional technique has a problem in that the coating material 53 peels off and the resistance to rotation is insufficient. In particular, this problem becomes apparent in an atmosphere as high as 60 to 80°C.

An object of the present invention is to shorten the heating time of the adhesive and to improve the bondability between the ring core and the covering material.

Structure of the Invention (Means for Solving Problems) The present invention comprises a step of applying a hardening adhesive to a ring portion core metal of a steering wheel core metal;
A step of heating the steering wheel core metal with adhesive applied to the ring portion core metal, and a step of setting the heated steering wheel core metal in an insert molding mold while the adhesive is being heated. The above-mentioned problem is attempted to be solved by adopting a technical means consisting of a step of insert-molding a synthetic resin and forming a covering material on the surface of the ring portion core metal.

(Function) The function of the present invention is not necessarily clear, and elucidation of its essence will be left to the future, but it is thought to be as follows.

That is, when the adhesive that is not covered with the covering material is heated, the adhesive is quickly heated, the evaporation of the solvent in the adhesive is promoted, and at the same time, the adhesive is cured, and at the same time, the bonding to the ring portion core bar progresses.

When the steering wheel core metal itself in such a state is set as an insert member in an insert molding mold, and a soft synthetic resin is insert-molded while the adhesive is heated, it is inserted into the insert molding mold. Due to the temperature and pressure of the injected synthetic resin, the adhesive exhibits adhesion to the molded covering material and joins it to the ring core metal.

(Example) Next, Examples 1 to 7 embodying the present invention will be described.
This will be explained based on the diagram.

In the steering wheel core metal 10 used in this embodiment, as shown in FIG. 2, a ring portion core metal 10a is supported by two spoke core metals 10c extending outward from a boss portion 10b.

This steering wheel core metal 10 is finished into a steering wheel by sequentially passing through a steam cleaning process, an adhesive application process, a setting process, a preforming process, a heating process, and a molding process shown in FIG.

[Steam cleaning process] During the manufacturing process of the steering wheel core 10, oil and contaminants adhere to the surface of the ring core 10a, so in this step, the ring core 10a is cleaned with organic solvent vapor. This is a process of cleaning the ring core metal 10a to remove the oil and the like.

As shown in FIG. 3, a moving means 11 is installed on the machine frame 1 and is mainly composed of a horizontal air cylinder 13 that expands and contracts in the horizontal direction and a vertical air cylinder 15 that expands and contracts in the vertical direction.

The piston rod 1 of the vertical air cylinder 15 is installed above the adhesive tank 3 which is installed at the lower left side of the machine frame 1 and contains the hardening adhesive A.
A steering wheel core metal 10 is locked to 5a.

Next, when the horizontal air cylinder 13 is actuated, the steering wheel core metal 10 is lowered into the solvent tank 2. In the solvent tank 2, 1,1,1-trichloroethylene is stored as an organic solvent S, and the organic solvent S in the solvent tank 2 is heated to a boiling point temperature (74
℃). Therefore, the vapor is generated on the organic solvent S and comes into contact with the surface of the steering wheel core metal 10.

A motor 20 installed at the top of the vertical air cylinder 15 rotates a sprocket 23, which rotates a chain 24 and the chain 24.
The steering wheel core metal 10 rotates for 10 seconds to 2 minutes via the sprocket 19 at the tip of the piston rod 15a over which the steering wheel core 10 is stretched.

Then, the vapor of the organic solvent S that collided with the surface of the steering wheel core metal 10 is partially condensed and becomes a highly pure liquid, which is then transferred to the steering wheel core metal 1.
0 and elutes oil or other contaminants adhering to the surface. Since the steering wheel core metal 10 is rotating, droplets of the organic solvent S condensed from its surface are shaken off. Moreover, the steering wheel core metal 10 is heated at the same time.

[Adhesive Application Step] This step is a step of applying a hardening adhesive A to the surface of the ring portion core metal 10a heated in the above step.

Steering wheel core metal 10 in a heated state
is lowered again through the adhesive tank 3 by the moving means 11, and immersed in the hardening adhesive A contained in the adhesive tank 3. The adhesive A may be any adhesive as long as it has thermosetting properties and exhibits adhesive properties when the solvent is evaporated after being applied in the form of a solution. Examples of such adhesives include urethane resin adhesives, epoxy resin adhesives, acrylic resin adhesives, and polyamide adhesives containing curing agents.

When the steering wheel core metal 10 is rotated once or twice, the adhesive A is applied to the ring portion core metal 10a.

[Setting Step] This step is a step in which the adhesive A applied to the surface of the ring core bar 10a is made to have a uniform film thickness.

The motor 20 is started, and the vertical air cylinder 15 is operated to move the steering wheel core 10 coated with the adhesive A above the adhesive tank 3 while rotating it. At this time, the steering wheel core metal 10 is rotated at a rate of 10 times per minute.
Spin for 10-120 seconds at ~50 rotations.
Then, as shown in FIG.
Adhesive A hardens to a uniform thickness on the surface of a. Note that when the steering wheel core bar 10 is not rotated, the adhesive A drips on the surface of the ring core bar 10a, and the surface portion thereof solidifies, resulting in uneven film thickness and an increase in the film thickness. An unsolidified portion of adhesive A remains inside the portion.

When a coating material, which will be described later, is formed on the surface of the ring core metal 10a to which the adhesive with uneven film thickness is applied, the unsolidified portion is formed between the coating material and the ring core metal 10a.
flows between the two, and the two do not join. in this way,
If the adhesive A applied to the ring core bar 10a is not pressed against the covering material while the solvent evaporates under a uniform film thickness and the adhesive has an appropriate adhesiveness, its adhesive performance will not be sufficient. Not demonstrated.

[Preforming Step] In this step, prior to forming the covering material on the ring core metal 10a, a lower cover is formed on the lower side of the boss portion 10b, and the spoke core metal 10c is
This is the process of forming a coating on the material and pre-shaping it into a shape that is almost similar to the final product.

Depending on the specifications of the steering wheel, this step may be omitted and the lower cover etc. may be molded together with the ring portion core metal 10a in a molding step to be described later.

After the steering wheel core metal 10 coated with adhesive A is set in an insert mold (not shown), the boss portion 10b and the spoke portion core metal 10 are
Insert molding is performed on C as it is or with a resin insert in a predetermined shape to form a lower cover and the spoke core metal 10c.
Preliminary coating.

[Heating process] In this process, the adhesive is heated to harden and bonded to the ring core bar 10a, and the adhesive is also bonded to the covering material in the molding process described later. , is a process of adjusting the adhesive performance of the adhesive.

As shown in FIG. 5, the preformed steering wheel core metal 10 is set horizontally on the four support members 31 on the dielectric heating device 30. A ring-shaped heating member 32 is disposed concentrically around the set steering wheel core metal 10, and this heating member 32 has a built-in coil. When a high frequency current is applied to the coil from the high frequency generating means 33, the ring portion core metal 1
0a and the adhesive A applied thereto generate heat. The exothermic temperature of adhesive A is the ring part core bar 10.
It is sensed by a sensor 34 provided close to a, and is input to a control device 35. The control device 35
controls the high frequency generator 33 based on the set temperature of the ring core metal 10a stored in advance.

[Forming process] This process is a process of forming a covering material on the surface of the ring portion core bar 10a.

The steering wheel core 10, which has adhesive A applied to its surface and is under heating, is
For example, an upper mold 41 and a lower mold 42 of the structure shown in FIG.
After setting in an insert molding die 40 consisting of the following, soft polyvinyl chloride resin is injected into the cavity 44 through the gate 43.

Then, as shown in FIG. 7, the ring part core bar 10
A covering material 26 is formed on the surface of a, and the two are firmly joined by adhesive A.

To describe the functions and effects of this embodiment configured as described above, in the steam cleaning step of cleaning the steering wheel core metal 10 with the vapor of the organic solvent S, oil adhering to the surface of the ring portion core metal 10a is removed. Other contaminants are thoroughly washed away by the highly pure organic solvent S. Therefore, the adhesive A exhibits excellent adhesive performance without being released from the surface of the ring core metal 10a during the adhesive application process. Moreover, since the steering wheel core metal 10 is heated by the vapor of the organic solvent S, the heated steering wheel core metal 10 can be immediately moved to the next adhesive application process.

In the setting process, the steering wheel core 10 to which the adhesive A has been applied is set while rotating, so that the film thickness of the adhesive A becomes uniform, and when the coating material 26 is formed after that, its adhesive performance is improved. It performs well.

In the heating process after preforming, the adhesive A is dielectrically heated, so that the adhesive A causes a curing reaction while bonding to the ring core bar 10a, and the surface side of the adhesive layer has good adhesive performance. demonstrate.

Therefore, the insert molding die 40 in the molding process
The steering wheel core metal 1 is heated to
After setting 0, when the soft polyvinyl chloride resin is insert-molded, the coating material 26 obtained by the molding and the adhesive A are firmly bonded, and the coating material 26 is formed around the ring core bar 10a. There is no rotation. Furthermore, unlike the prior art, the adhesive A of the ring core 10a is dielectrically heated before being coated with the covering material 26, that is, while the adhesive A is exposed on the surface of the ring core 10a. Therefore, the adhesive A is heated quickly. As a result, the steering wheel manufacturing cycle is shortened and productivity can be improved. Furthermore, since the adhesive A is heated by the dielectric heating method, the adhesive A is heated uniformly, and the covering material 26 is evenly bonded to the ring core bar 10a.

The present invention is not limited to the above embodiments, but
For example, the following embodiment can also be implemented.

(1) Any heating method may be used to heat the steering wheel core 10 after the adhesive A has been applied to the ring core 10a, but the melting heating method using high frequency is the most preferable from the viewpoint of uniform and quick heating. .

(2) Polyurethane resin is used as the soft synthetic resin R.

Effects of the Invention As detailed above, the present invention is configured such that the coating material is formed while the hardening adhesive is applied to the ring core metal, heated, and then heated. Therefore, the time for heating the adhesive can be shortened, and the adhesive performance can be improved, which is an excellent effect.

[Brief explanation of drawings]

Fig. 1 is a process diagram showing the method of the present invention, Fig. 2 is a front view of the steering wheel core metal, Fig. 3 is a longitudinal sectional view of the steam cleaning process, Fig. 4 is a partial side view of the ring portion core metal, and Fig. 4 is a partial side view of the ring portion core metal. Fig. 5 is a perspective view of the heating device, Fig. 6 is a vertical sectional view of the insert molding die, Fig. 7 is a sectional view of the coating material coated on the ring core metal, and Fig. 8 is a steering wheel according to the prior art. FIG. 9 is a partially cutaway front view showing - in FIG. 8.
It is a sectional view of the direction. 10... Steering wheel core metal, 10a...
...Ring part core metal, 40...Insert molding mold,
A...Adhesive, R...Synthetic resin.

Claims (1)

[Scope of Claims] 1. A step of applying thermosetting adhesive A to the ring portion core metal 10a of the steering wheel core metal 10, and a steering wheel with the adhesive A applied to the ring portion core metal 10a. The process of heating the wheel core metal 10 and the heated steering wheel core metal 10
A method for producing a steering wheel, comprising the steps of insert molding a soft synthetic resin R onto a heated adhesive layer A by setting the adhesive in an insert molding mold 40. 2. The method for manufacturing a steering wheel according to claim 1, wherein heating of the steering wheel core metal 10 is performed by a dielectric heating method. 3. Claim 1, wherein the soft synthetic resin R is a polyvinyl chloride resin or a polyurethane resin.
Method of manufacturing the steering wheel described in Section 1.