JPH0647262B2 - Steering wheel manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a steering wheel in which a rim core metal is covered with a coating layer made of urethane foam resin.

[0002]

2. Description of the Related Art Conventional steering wheels of this type are
For example, as described in Japanese Utility Model Laid-Open No. 63-23182, a structure in which a rim core of a boss, a rim core and a spoke core is covered with a coating layer made of a soft synthetic resin is adopted. There is. This steering wheel has a large number of holes formed around the entire circumference of the rim core metal so that the rim core metal and the coating layer of soft synthetic resin do not run idle, and the spoke core metal and the rim core metal are joined together. The portion to be pulled is drawn to the lower side on the side where the driver is located to form a substantially eight shape, so that the meters can be easily seen from the inner space portion of the rim portion.

[0003]

In a steering wheel in which a large number of openings are formed in the entire rim cored bar, the large number of the openings are weak portions, which causes a problem in strength.
It is also difficult to form openings at equal intervals in the rim core bar, which causes cost increase.Furthermore, when the resin is foamed in the molding die, air is entrapped in the openings, which hinders foaming.
For example, as shown in FIG. 13, there is a problem that a void 5 is likely to occur in the coating layer 3 that covers the rim core metal 1 in the opening portions 4 at various places of the rim core metal 1. Further, if no opening is formed in the rim core metal, large voids 6 are generated in the weld portion of the coating layer 3 that covers the rim core metal 1, as shown in FIGS. 11 and 12. Also,
The joint portion between the rim core metal and the spoke core metal was liable to become an obstacle during resin foaming, which was a cause of defective molding.

The present invention has been made in view of the above-mentioned problems, and it is possible to reliably remove air from the molding die, without causing voids around the rim core metal, and in a stable state, the rim core. A steering wheel manufacturing method capable of manufacturing a steering wheel in which gold is coated with a urethane foam resin layer.

[0005]

A method of manufacturing a steering wheel according to the present invention comprises a central boss, an annular rim core metal, and
In a method for manufacturing a steering wheel, wherein at least a rim core made of a spoke core for connecting a boss and a rim core is covered with a coating layer made of a urethane foam resin, the rim core of the core is provided on the boss side. The rim cored bar is formed in a generally U-shaped cross-section that is open toward both sides, and both ends of the spoke cored bar are connected to the rim cored bar at a position lower than the center crossing position, and the rim cored bar is positioned from the inner surface side to the outer surface side at the upper position. A rim core bar of the core material is formed in which a through hole is formed, and the core material is arranged in the molding die with the connecting side of the rim core metal and the spoke core metal facing downward. Set a gate at the lower position of the mold, inject urethane resin raw material from the gate located at the lower side of this mold up to at least the position where the spoke core metal of the rim core metal is connected, and exhaust it at the top of the mold. Foam urethane resin raw material and foam rim core metal It is intended to cover with a coating layer made of resin.

[0006]

The manufacturing method of the steering wheel of the present invention is as follows.
The core is placed in the molding die with the connecting side of the rim cored bar and the spoke cored bar facing down, and from the gate set in the lower side of the rim cored bar of the cored material placed in this mold. Inject the urethane resin raw material up to the connection position of the spoke core metal of the rim core metal,
The urethane resin raw material is foamed while exhausting at the top of the mold. The air in the rim cored bar having a substantially U-shaped cross section flows upward along the annular rim cored bar due to this resin foaming, is exhausted from the opening in the upper part of the rim cored bar to the exhaust hole of the mold, and the inside of the coating layer No void is generated in the. In addition, the injected resin is filled in the joint between the rim core metal and the spoke core metal of the core material, so that foaming is ensured without hindering foaming, and the coating layer that covers the rim core metal is defective in molding. Never becomes.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will now be described with reference to the drawings.

1 to 3, reference numeral 10 denotes a steering wheel body, which is a steering wheel body 10.
Is a boss 11 and a boss plate 12 connected to the boss 11.
And a core material 15 composed of an annular rim core metal 13 located on the outer periphery of the boss plate 12, and spoke core metals 14 and 14 connecting the rim core metal 13 and the boss plate 12. ing. The boss 11 is fixed to the steering shaft.

The spoke cores 14 and 14 are fixed at their central portions to the lower front and rear outer sides of the boss plate 12 by welding, and both ends between the boss plate 12 and the rim core 13 are set to the driver side. It is drawn to the lower side and is formed in an eight shape.

The spoke cores 14 and 14 may be directly welded to the boss 11 without the boss plate 12.

Further, the rim core metal 13 is formed in a substantially U-shaped cross-section opening toward the boss 11 side.
Both ends of the spoke core metal 14 are coupled to the spoke 13 at a position below the center crossing position.

Further, a plurality of openings 18 penetrating from the inner surface side to the outer surface side are formed in the upper central position of the rim core bar 13, that is, within a range of ± 10 ° from the 180 ° position.

Then, as shown in FIGS. 3 and 4, a rim core metal 13 of the core material 15 and a part of the spoke core metals 14, 14 connected to the rim core metal 13 are covered with a foamed urethane resin. Layer 20 is coated.

Next, as shown in FIGS. 5 and 6, the core material 15 is arranged in the molding die 21, and the gate 22 is set on the molding die 21 by locating the core material 15 at a lower position. Then, this mold 21
At least the rim core metal 13 from the gate 22 of urethane resin raw material
And the spoke cores 14, 14 are injected up to the connecting position.
Then, as shown in FIG. 7, the molding die 21 is tilted by about 50 to 60 ° with the gate 22 side facing downward, and a foaming reaction is caused in the molding die 21.

Then, as shown in FIG. 8, the resin 24 flows while foaming along the rim core metal 13 of the core material 15, and the resin 24 joins from the left and right at the central position of the upper part, that is, at the 180 ° position. Then, the foaming gas is exhausted from the degassing exhaust hole 25 formed in the upper part of the molding die 21. Then, the air 26 in the rim core metal 13 of the core material 15 is filled with resin 24 as shown in FIGS. 9 and 10.
Flow to the upper part along the inner side of the rim core bar 13 from the opening 18 at the upper part of the rim core bar 13 to the vent hole of the molding die 21.
It is discharged to the outside of the molding die 21 via 25.

Further, the rim core bar 13 of the core member 15 and the spoke core bar
Since the injected resin has already been filled in the joint portion with 14, 14, the foaming is surely foamed without being hindered.

In this way, the core material 15 is arranged in the molding die with the connecting side of the rim core metal 13 and the spoke core metals 14, 14 facing downward, and the core material is arranged in the molding die 21. The raw material of urethane resin 24 is injected from the gate 22 set at the lower side position of the rim core metal 13 of 15 to at least the coupling position of the rim core metal 13 and the spoke core metals 14, 14 and the gas is generated at the upper part of the molding die 21. The material of the urethane resin 24 is foamed while exhausting from the extraction exhaust hole 25. By this resin foaming, the air in the rim core metal 13 of the core material 15 flows upward along the annular rim core metal 13 and is exhausted from the opening 18 in the upper part of the rim core metal 13 to the exhaust hole 25 of the molding die 21. Therefore, no void is generated in the coating layer 20. Further, the resin is surely foamed at the joints between the rim core metal 13 of the core material 15 and the spoke core metals 14, 14 without hindering the foaming of the resin, and the coating layer 20 does not become defective.

[0018]

According to the present invention, the urethane foam resin coating the rim cored bar of the core material can surely remove air from the molding die without entraining air inside the rim cored bar. It is possible to cover the rim core metal with the urethane foam resin layer in a stable state without generating voids around the core metal. Further, since the injected resin is filled in the joint portion between the rim core metal and the spoke core metal of the core material, the resin is surely foamed without being hindered from foaming, and the coating layer can be reliably molded.

[Brief description of drawings]

FIG. 1 is a front view of a core material of a steering wheel showing an embodiment of a method for manufacturing a steering wheel of the present invention.

FIG. 2 is a plan view of the above core material.

FIG. 3 is a front view of the above steering wheel.

FIG. 4 is a sectional view of the same rim portion.

FIG. 5 is a partial perspective view showing the mold open state of the same mold.

FIG. 6 is an explanatory view showing a mold open state of the same molding die.

FIG. 7 is an explanatory view showing a state in which foaming is carried out in the same molding die.

FIG. 8 is an explanatory diagram showing a flow of resin when the resin is foamed.

FIG. 9 is an explanatory diagram showing a final state of the resin flow when the resin is foamed.

FIG. 10 is a cross-sectional view showing a final state of the resin flow at the time of resin foaming.

FIG. 11 is a cross-sectional view of the rim portion of the steering wheel showing a state in which voids are formed in the coating layer.

FIG. 12 is a cross-sectional view of the rim portion of the steering wheel showing another state in which a void is formed in the coating layer.

FIG. 13 is a cross-sectional view of the rim portion of the steering wheel showing another state in which a void is formed in the coating layer.

[Explanation of symbols]

 10 Steering wheel body 11 Boss 13 Rim core metal 14 Spoke core metal 15 Core material 18 Opening 20 Cover layer 21 Mold 22 Gate 24 Resin

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B29L 31:30 4F

Claims (1)

[Claims] 1. A steering wheel in which at least a rim core of a central boss, an annular rim core, and a spoke core for connecting the boss and the rim core is covered with a coating layer made of urethane foam resin. In the manufacturing method, the rim cored bar of the core material is formed into a substantially U-shaped cross-section that opens toward the boss side, and both ends of the spoke cored bar are connected to the rim cored bar at a position below the center crossing position. Then, an opening penetrating from the inner surface side to the outer surface side is formed at an upper position of the rim cored bar, and the core material is disposed in the molding die with the connecting side of the rim cored bar and the spoke cored bar facing down. Then, a gate is set at the lower position of the rim cored bar of the core material arranged in this molding die, and urethane resin raw material is supplied from the gate located below this molding die at least the spoke core of the rim cored bar. Pour up to about the joining position of Method of manufacturing a steering wheel, characterized in that the coating with a coating layer by foaming Tan resin material comprising a rim core metal foamed urethane resin.