JPH04321451A - Steering wheel made of polyurethane - Google Patents

Abstract

PURPOSE:To secure intended dimension and shape for the center hole of a brittle member arranged at the boss part, allow easy formation of covering layer, and cover the hole certainly with a lid by making the steering wheel from the mentioned brittle member approx. in cylindrical form and consisting of plastics and a core of metal for the steering wheel, which are covered with a covering layer made of half-hard foaming polyurethane. CONSTITUTION:As an impact energy absorbing body, a brittle member 10 made of plastics and approx. in cylindrical form is arranged over the boss part B. An insert 18 made of hard plastics in a ring form is arranged at the peripheral edge of a hole 11 provided in the oversurface of this brittle member. Along the peripheral circumference of the hole 11, this insert is equipped at the undersurface with a plurality of projections 21 to be inserted in the brittle member. The brittle member and the core C of steering wheel are covered with a covering layer 5 made of half-hard foaming polyurethane.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is characterized in that a roughly cylindrical brittle member made of synthetic resin as an impact energy absorber is placed above a boss portion, and the periphery of this brittle member and a steering wheel core metal is semi-circular. The present invention relates to a urethane steering wheel covered with a coating layer made of hard urethane foam.

0002

[Prior Art and its Problems] Conventionally, a steering wheel is known in which a brittle member made of synthetic resin such as hard urethane foam or styrene foam is disposed in the central boss portion of the steering wheel as an impact energy absorber. (Refer to Japanese Patent Application Laid-Open No. 62-263014).

[0003] In the steering wheel described in this publication, the brittle member forms a surrounding coating layer or is attached with a predetermined metal fitting and is disposed at the boss portion. Therefore, the number of man-hours required for assembling the brittle member to the boss portion and the number of parts to be assembled are required, increasing the number of man-hours required for manufacturing the steering wheel.

In this case, in order to reduce the number of man-hours for assembling the brittle members and the number of parts to be assembled, and to further improve the appearance of the steering wheel, the brittle members and the steering wheel core metal are used as inserts, and their surroundings are covered with semi-hard foamed urethane. It is conceivable to manufacture the steering wheel in one piece by covering it with a coating layer consisting of:

In this case, it is necessary to form the brittle member into a substantially cylindrical shape, and to arrange the steering wheel components such as the horn switch mechanism in the hole in the center.
Further, after the component is disposed in the hole, it becomes necessary to cover the opening of the hole with a lid so that the inside cannot be seen.

However, when covering a brittle member with a covering layer made of semi-rigid urethane foam,
The approximately cylindrical brittle member expands due to the heat of molding the semi-rigid urethane foam, and the hole in the center of the brittle member becomes larger in whole or in part, and a lid body is appropriately disposed to close this hole. I become unable to do so.

[0007] The present invention solves the above-mentioned problem, and the steering wheel core and the brittle member made of a substantially cylindrical synthetic resin and arranged in the boss portion are surrounded by a covering made of semi-rigid foamed urethane. In a steering wheel coated with a layer, the cover layer can be formed by ensuring the size and shape of the hole in the center of the brittle member, and the lid can be appropriately placed to cover the hole. The purpose is to provide steering wheels.

[0008]

[Means for Solving the Problems] In the steering wheel according to the present invention, a generally cylindrical brittle member made of synthetic resin as an impact energy absorber is disposed in the upper part of the boss portion, and the brittle member and the steering wheel core are arranged in the upper part of the boss portion. A steering wheel made of urethane, the periphery of which is covered with a covering layer made of semi-hard foamed urethane, and a lid is disposed in a central hole of the brittle member, the brittle member A ring-shaped insert body made of a hard synthetic resin is arranged on the upper surface of the central hole periphery and is disposed before the coating layer is formed, and on the lower surface of the insert body,
It is characterized in that a protrusion that is inserted into the brittle member is formed continuously or discontinuously along the circumference of the hole.

[0009]

[Operations and Effects of the Invention] In the steering wheel according to the present invention, at the periphery of the central hole on the upper surface of the brittle member,
A ring-shaped insert made of hard synthetic resin is provided, and a protrusion protruding from the lower surface of the insert is inserted into the periphery of the hole of the brittle member.

[0010] Therefore, when molding a covering layer made of semi-rigid urethane foam, if an insert body is placed in advance by inserting a protrusion into the periphery of the hole on the upper surface of the brittle member, the protrusion of the insert body can be , are formed continuously or discontinuously along the periphery of the hole in the brittle member, so even if the hole in the brittle member tries to enlarge in whole or in part due to molding heat, the periphery of the hole in the brittle member cannot be positioned. The cover layer made of semi-rigid urethane foam can be molded by controlling the hole portion of the brittle member to a predetermined size.

Therefore, the urethane steering wheel according to the present invention can be manufactured while ensuring the size and shape of the hole in the center of the brittle member, and the lid can be appropriately disposed to cover the hole.

[0012] Furthermore, the insert body made of hard synthetic resin disposed in the brittle member is disposed on the upper surface of the brittle member, and does not have to be disposed over the entire vertical length of the brittle member. can be prevented from becoming a hindrance when absorbing impact energy.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The steering wheel W of the embodiment is shown in FIG.
・As shown in 7, an annular ring part R and a ring part R
boss part B located at the center of the ring part R and boss part B
and three spoke portions S connecting the two.

Further, the steering wheel W includes a steering wheel core metal C, and the steering wheel core metal C has a boss 1 disposed at the lower part of the boss portion B and connected to a steering shaft (not shown), and a boss 1 connected to the boss 1. A boss plate 2 to be welded, a ring part core metal 3 disposed on the ring part R, and a spoke part core metal 4 disposed in each spoke part S and welded to the boss plate 2 and the ring part core metal 3. , is composed of.

In this steering wheel W, the periphery of the steering wheel core C and the brittle member 10 disposed above the boss portion B is covered with a covering layer 5 made of semi-hard foamed urethane. .

When an impact force is applied from above the boss portion B, the brittle member 10 undergoes brittle fracture so as to reduce its height in the vertical direction, thereby absorbing the impact energy. As shown in Figures 1.5 to 7, it is made of synthetic resin such as styrene foam made of hard urethane foam, foam beads, etc., and a horn switch mechanism H, which will be described later, is installed in the center. A hole 11 penetrating vertically for
It is approximately cylindrical in shape.

Two-stage grooves 12 and 13 are formed around the entire circumference of the hole 11 on the upper surface side of the brittle member 1, and an insert (to be described later) is formed in a portion away from the hole 11. Four insertion holes 14 are formed into which the projections 21 of the body 18 are inserted.

Note that 15 is a hole for preventing peeling of the coating layer 5 when the coating layer 5 is formed, and 16 is a positioning projection that engages with the core bar 4 of each spoke portion.

A ring-shaped insert body 18 made of a hard synthetic resin such as ABS resin is disposed on the upper surface of the brittle member 10 around the periphery of the hole 11.

As shown in FIGS. 2 to 4, this insert body 18 includes a base 19 which is flat and annular, and a base 19.
9, and a cylindrical portion 20 extending downward from the inner circumferential edge of the cylindrical portion 9, and convex portions 2 at four locations on the outer circumferential surface of the cylindrical portion 20.
0a is formed. The outer diameter dimensions of the base 19 are shown in Figure 1.
- As shown in 5 and 6, the dimension is such that it can fit into the first groove 12 of the brittle member 10, and the outer diameter dimension of the cylindrical part 20 excluding the convex part 20a is the same as the second groove 13 of the brittle member 10. The dimensions are such that it can fit into the

The insert body 18 is provided with protrusions 21 that extend downward from four locations on the base 19 and can be inserted into the respective insertion holes 14 of the fragile member 10.

To explain the horn switch function H, as shown in FIG. 1, the horn switch mechanism H is composed of a fixed contact plate 24 and a movable contact plate 25, each connected to a lead wire (not shown). There is. The fixed contact plate 24 becomes the negative electrode side of the horn switch circuit, and the movable contact plate 25 becomes the positive electrode side of the horn switch circuit. 24a
- 25a is a contact point of each plate 24, 25.

[0024]The movable contact plate 25 is
It is fixed to a plurality of protrusions 26a extending downward from the lower surface of the synthetic resin horn pad 26 using flanged insulating spacers 27 screwed from below the substrate 23. Coil springs 28 are respectively fixed to a plurality of protrusions 26b extending downward from the lower surface of the horn pad 26 to separate the movable contact plate 25 fixed to the horn pad 26 from the fixed contact plate 24.

The horn pad 26, together with the operating section of the horn switch mechanism H, functions as a lid for covering the hole 11 of the brittle member 10 after the coating layer 5 of the steering wheel W is formed.

This horn switch mechanism H locks one locking leg 23a extending from the lower surface of the substrate 23 into a locking hole 5a formed in the covering layer 5, and By forming the plurality of convex portions 23b formed in the plurality of grooves 23b (see FIGS. 1 and 7) in the coating layer 5, the brittle member 10 can be placed in the hole 11. Become.

Next, manufacturing of this steering wheel W will be explained. First, the steering wheel core metal C is manufactured by welding the boss 1, boss plate 2, etc. Further, the protrusion 21 is inserted into each insertion hole 14, the cylindrical portion 20 is fitted into the second groove 13, and the base 19 is fitted into the first groove 12, so that the upper surface of the brittle member 10 is An insert body 18 is disposed around the periphery of the hole 11. Note that the insert body 18 has each convex portion 20 of the cylindrical portion 20.
Since a is press-fitted into the side surface of the second groove 13,
The brittle member 10 is prevented from coming off the periphery of the hole 11.

Thereafter, the brittle member 10 with the insert body 18 disposed thereon is placed at the boss portion B of the steering wheel core C using the positioning protrusion 16.

Then, the steering wheel core C with the brittle member 10 assembled thereto is placed in the split molds 31 and 32 in an open state.
The cover layer 5 is then placed in a rim mold 30 consisting of a rim mold 30, and the coating layer 5 is formed. The reason why the semi-rigid foamed urethane material is injected into the mold at low pressure using the rim mold 30 is that the brittle member 10 will be damaged if the pressure is high.

[0030] During molding, an insert body 18 is placed around the periphery of the hole 11 on the upper surface of the brittle member 10, with the protrusion 21 inserted therein. Therefore, each insertion hole 14
A protrusion 21 inserted into the hole 11 of the brittle member 10 is disposed along the periphery of the hole 11 of the brittle member 10.
Even if 1 tries to become larger in whole or in part due to molding heat, the position of the periphery of the hole 11 of the brittle member 10 is regulated,
This means that the covering layer 5 made of semi-rigid urethane foam can be molded by ensuring that the holes 11 of the brittle member 10 have a predetermined size.

After releasing the mold, the lower cover 6 is fixed with the screws 7 (see FIG. 7), and the horn switch mechanism H is assembled using the locking legs 23a and the convex portions 23b, thereby manufacturing the steering wheel W. Can be done. When assembling the horn switch mechanism H, the covering layer 5 can be formed while ensuring the dimensions and shape of the hole 11 of the brittle member 10 are as specified. It can be arranged in the section 11.

Furthermore, in the steering wheel W of the embodiment, the insert body 18 is arranged on the upper surface of the brittle member 10, and it is not necessary to arrange it over the entire length of the brittle member 10 in the vertical direction. The insert body 18 does not prevent the brittle fracture of the brittle member 10 that contracts in the vertical direction when impact energy is absorbed.

In the embodiment, the protrusion 21 provided on the insert body 18 is shown as being composed of a plurality of pins discontinuously (intermittently) formed along the periphery of the hole 11 of the brittle member 10. Ta. However, this protrusion
Since it is sufficient to restrict the expansion of the hole 11 of the brittle member 10 during molding, it may be formed in a continuous shape along the periphery of the hole 11, for example, in a cylindrical shape.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a steering wheel showing an embodiment of the present invention.

FIG. 2 is a plan view of an insert body used in the same example.

FIG. 3 is a side view of the insert body used in the same example.

FIG. 4 is a sectional view taken along line IV-IV in FIG. 2;

FIG. 5 is a plan view of a brittle member provided with an insert body of the same embodiment.

FIG. 6 is a sectional view taken along VI-VI in FIG. 5;

FIG. 7 is a plan view of the steering wheel of the same embodiment with the horn switch mechanism removed.

FIG. 8 is a cross-sectional view showing the state during molding of the coating layer in the same example.

[Explanation of symbols]

5...Covering layer, 10... Brittle member, 11...hole, 18...insert body, 21...Protrusion, 26... (lid body) horn pad, W...Steering wheel, B...Boss part, C...Steering wheel core metal, H...Horn switch.

Claims (1)

[Claims] Claim 1: A generally cylindrical brittle member made of synthetic resin as an impact energy absorber is disposed above the boss portion, and a covering made of semi-hard foamed urethane surrounds the brittle member and the steering wheel core. A steering wheel made of urethane is provided with a lid body disposed in a central hole of the brittle member, the urethane steering wheel being covered with a layer of A ring-shaped insert body made of a hard synthetic resin is arranged before the coating layer is formed, and on the lower surface of the insert body,
A steering wheel made of urethane, characterized in that protrusions that are inserted into the brittle member are formed continuously or discontinuously along the circumference of the hole.