JPH11105715A - Lower cover for steering wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the mountability of an air bag device by suppressing a releasability from lowering in forming. SOLUTION: A lower cover 8 is made of synthetic resin and provided with a temporary fixing part 19 for temporarily fixing a mounting bolt 26 to fix an air bag device to a steering wheel main body 1. The temporary fixing part 19 is provided with a locking leg 21 having a hook part 21a on this side 19a, and its inner peripheral surface is formed in a cylindrical shape tapered divergently from this side 19a to a top end side 19c. At the temporary fixing part 19, the hook part 21a is locked to a locking groove 27a in the outer periphery of the head part 27 of the bolt 26, and the bolt 26 is fixed temporarily with a bolt thread part 28 facing toward the steering wheel main body 1 side. Then a plurality of ribs 22 having a guide surface 22a in parallel with a temporary fixing part axial direction O are formed on the inner peripheral surface of the temporary fixing part 19 so that the bolt head part 27 can be guided from a temporary fixing position X to a mounting bolt screwing position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lower cover made of synthetic resin for covering a lower portion of a steering wheel provided with an airbag device, and more particularly, to temporarily fixing mounting bolts for mounting the airbag device to a steering wheel body. The present invention relates to a lower cover having a temporary fixing portion.

[0002]

2. Description of the Related Art Conventionally, a lower cover made of a synthetic resin for covering a lower portion of a steering wheel is disclosed in Japanese Unexamined Patent Publication No. 8-19275.
As described in Japanese Patent No. 4, there is known an apparatus having a temporary fixing portion for temporarily fixing a mounting bolt for mounting an airbag device to a steering wheel body.

[0003] The temporary fixing portion is provided with a locking leg having a hook projecting to the inner peripheral side on the base portion side, and is formed in a cylindrical shape with the front end side facing the steering wheel body side. This temporary fixing portion locks the hook portion of the locking leg in a locking groove provided on the outer periphery of the cylindrical head of the mounting bolt,
The mounting bolt was temporarily fixed so that the screw portion of the mounting bolt faces the steering wheel body.

[0004] When the airbag device is mounted on the steering wheel body, a lower cover, in which mounting bolts are temporarily fixed, is assembled on the steering wheel body side, and the airbag device is arranged on the steering wheel body. After that, the mounting bolt is pushed into the front end side of the temporary fixing portion so that the hook portion is disengaged from the locking groove, and is inserted into the screw hole of the airbag device through the insertion hole of the steering wheel body and the screw portion of the mounting bolt. The airbag device is attached to the steering wheel body by turning the mounting bolt and screwing it into the screw hole of the airbag device, and pressing the mounting bolt head against the periphery of the insertion hole of the steering wheel body. Was.

[0005] When the lower cover is provided integrally with the temporary fixing portion for temporarily fixing the mounting bolt as described above,
Compared to the case where a temporary fixing part is separately provided on the steering wheel body side, the temporary fixing part itself and the fixing means for providing the temporary fixing part can be omitted, and the number of parts and the number of assembly steps of the steering wheel can be reduced. it can.

[0006]

However, in the above-mentioned conventional lower cover, since the temporary fixing portion is formed in a cylindrical shape, the releasability at the time of molding (at the time of injection molding) of the synthetic resin lower cover is taken into consideration. The inner peripheral side of the temporary fixing portion was tapered. Further, since the hook portion protruding inward is provided on the base portion side of the temporary fixing portion, the tapered shape is used to increase the opening diameter from the base portion side to the distal end side.

Therefore, when the airbag device is attached to the steering wheel body, when the temporarily fixed mounting bolt is moved to the distal end side of the temporary fixing portion, the mounting bolt rattles, and the screw portion of the mounting bolt is accurately adjusted. There has been a case where the airbag device does not enter into the screw hole side of the airbag device, so that the operation of mounting the airbag device cannot be performed smoothly.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide a lower cover of a steering wheel capable of suppressing a decrease in releasability at the time of molding and improving the workability of mounting an airbag device. With the goal.

[0009]

The lower cover according to the present invention is made of synthetic resin which covers a lower portion of a steering wheel provided with an airbag device, and has a mounting bolt for mounting the airbag device to a steering wheel body. A temporary fixing portion for temporarily fixing is provided. The temporary fixing portion includes a locking leg having a hook portion protruding inwardly on a base portion side, and a front end side toward the steering wheel body side. The peripheral surface has a cylindrical shape with a tapered surface extending from the base portion side to the distal end side, and the hook portion of the locking leg is locked in a locking groove provided on the outer periphery of the cylindrical head of the mounting bolt. A lower cover of the steering wheel for temporarily fixing the mounting bolt with the screw portion of the mounting bolt facing the steering wheel body side, wherein the mounting is performed on an inner peripheral surface of the temporary fixing portion. A plurality of ribs having a guide surface parallel to the axial direction of the temporary fixing portion are formed so as to guide the head of the bolt from the temporary fixing position to the screwing position of the mounting bolt. I do.

[0010]

In the lower cover according to the present invention, the mounting bolts temporarily fixed to the temporary fixing portions are pushed into the steering wheel main body side so that the airbag device is mounted on the steering wheel main body. The hook of the locking leg is detached from the groove, and the mounting bolt moves toward the steering wheel body.

At this time, each of the plurality of ribs provided on the inner peripheral surface of the temporary fixing portion guides the head of the mounting bolt from the temporary fixing position to the screwing position of the mounting bolt, respectively. Since the guide surface is parallel to the axial direction, the mounting bolt is guided to a predetermined screwing position without rattling, and then the mounting bolt is turned and tightened, so that the airbag is attached to the steering wheel body. The device can be mounted.

[0012] Even if the temporary fixing portion is provided with a rib having a guide surface parallel to the axial direction of the temporary fixing portion on the inner peripheral surface,
Since those ribs are partial, if the inner peripheral surface other than the ribs is formed as a tapered surface that extends from the base portion side to the distal end side, it is possible to minimize the decrease in the releasability of the temporary fixing portion during molding. .

Therefore, in the lower cover according to the present invention, it is possible to suppress the releasability at the time of molding and to improve the workability of mounting the airbag device.

[0014]

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

As shown in FIGS. 1 and 2, the steering wheel W of the embodiment has an annular ring portion R, a central boss portion B, and two spokes connecting the ring portion R and the boss portion B. Unit S. The steering wheel W is composed of the steering wheel main body 1 and the airbag device 30 disposed above the boss B on the components.
And is composed of

The airbag device 30 includes a bag-shaped airbag 31 that is folded and stored to be inflatable, an inflator 33 that supplies gas for inflating the airbag 31,
A pad 34 that covers the folded airbag 31, a bag holder 35 that holds the airbag 31, the inflator 33, and the pad 34, a support plate 37 that is connected to the bag holder 35 via a horn switch 36,
It is provided with. As shown in FIG. 3, the support plate 37 is provided with mounting brackets 38 to which nuts 38b are welded on both left and right sides.
Sets the airbag device 30 in the steering wheel body 1
To form a screw hole 38a for attachment to the base.

Reference numeral 32 denotes an annular retainer for attaching the airbag 31 and the inflator 33 to the bag holder 35. The horn switch 36
A plurality is provided between the bag holder 35 and the support plate 37.

The steering wheel body 1 includes a metal core 2 for connecting the ring portion R, the boss portion B, and the spoke portion S.
And part of the spoke portion S and the ring portion R in the cored bar 2
And a lower cover 8 that covers a lower portion of the boss portion B.

The metal core 2 has four mounting holes (not shown) for fixing the lower cover 8 with screws 6 at predetermined positions, and airbag devices 30 at the left and right sides near the center.
The mounting seat 4 for mounting is provided. Each mounting seat 4
Is provided with a horizontal wall portion 4a, a vertical wall portion 4b, and an upper wall portion 4c, and a mounting bolt 26 for mounting the airbag device 30 is inserted into a bent portion between the horizontal wall portion 4a and the vertical wall portion 4b. It is provided with an insertion hole 4d extending long in the vertical direction.

The mounting bolt 26 has a head 27 having a columnar shape and having a locking groove 27a all around its outer peripheral surface,
And a threaded portion 28 extending from the screw 7.
The width of the insertion hole 4 d of the mounting seat 4 is set smaller than the outer diameter of the head 27 of the mounting bolt 26 and larger than the outer diameter of the screw portion 28.

The lower cover 8 is formed by injection molding from a synthetic resin material such as polypropylene, and has a bottom wall 9 and a bottom wall 9.
And a peripheral wall 24 extending upward from the peripheral edge of the peripheral portion.

As shown in FIGS. 2 and 4, the bottom wall 9 is formed at the center thereof with an insertion hole 10 for projecting the portion of the boss B in the cored bar 2, and around the insertion hole 10, As shown in FIG. 4, a hole 9 is formed. Further, mounting bosses 12 having mounting holes 12a for screwing the lower cover 8 to the cored bar 2 with screws 6 are formed on the bottom wall 9 at predetermined four locations. Furthermore, from the bottom wall 9 to the peripheral wall 24
, A plurality of reinforcing ribs 13 are formed.
Further, mounting bolts 2 are provided at predetermined positions on the left and right sides of the peripheral wall 24.
6 is formed with an insertion hole 24a into which a jig for pushing or tightening 6 is inserted.

The large meat steal portions 11a in the vicinity of the insertion hole 10 in the meat steal hole 11 are disposed on the left and right sides of the insertion hole 10, respectively, where the temporary fixing portions 19 are arranged and the interference with the coating layer 5 of the spoke portion S. It is formed not to be. Further, in the vicinity of each of the temporary fixing portions 19, when the temporary fixing portion 19 is raised and locked from the state after the injection molding, the support wall portion 17 described later does not unnecessarily interfere, and In order to maintain the connection state of the stopping portion 19, the small meat stealing portion 11b
Are formed.

Each of the temporary fixing portions 19 is formed in a cylindrical shape, and when the lower cover 8 is released from the mold, the two-dot chain line on the left side and the solid line on the right side in FIG. 4, or as shown in FIGS. , The axial direction is arranged vertically. These temporary fixing portions 19
A support wall portion 17 having a U-shaped cross section is connected to the outer peripheral surface, and each support wall portion 17 is connected to the periphery of the small thickness stealing portion 11b via thin connecting portions 15. Then, after releasing the lower cover 8, the respective temporary fixing portions 19 are raised so as to twist the connecting portions 15, 15, and as shown in FIGS. Each temporary fixing portion 1 can be locked by locking the locking claw 16 provided on the peripheral edge.
9 can be arranged in a predetermined position.

Reference numeral 14 denotes a support base provided with a concave portion 14a for supporting the outer peripheral surface on the lower side when the temporary fixing portion 19 is raised, and protrudes upward from the bottom wall 9.

Each of the temporary fixing portions 19 is provided with three locking legs 21 on the base portion side 19a of the cylindrical main body 20. Each locking leg 21 has a notch 1
9b is provided, it is configured to be able to bend in the radial direction of the main body 20, and a hook 21a protruding inwardly is provided at the tip of the base side 19a. The inner peripheral surface 20a of the main body 20 has a base portion side 19a except for a rib 22 described later.
To the distal end side 19c.

On the inner peripheral surface of each temporary fixing portion 19 of the embodiment, three ribs 22 each having an arc-shaped guide surface 22a parallel to the axial direction O of the temporary fixing portion main body 20 are formed. Have been. These ribs 22 can guide the head 27 of the mounting bolt 26 from the temporary fixing position X shown by a solid line in FIG. 7 to a screwing position where the tip of the screw portion 28 of the mounting bolt 26 hits the end of the screw hole 38a. As shown in FIG.
And are evenly arranged radially.

The manner of assembling the steering wheel W according to the embodiment will be described. First, the lower cover 8 formed by injection molding is used.
Raises each of the temporary fixing portions 19 to be supported by the support base portion 14, and the locking claw 16 supports the support wall portion 1.
7 is locked. Also, the hook 21a of the locking leg 21 in each temporary fixing portion 19 is locked in the locking groove 27a so that the screw portion 28 faces the distal end side 19c, and the mounting bolt 26 is temporarily fixed to each temporary fixing portion 19. Let it stop.

Further, the lower cover 8 is attached to the metal core 2 by screwing the screws 6 by aligning the mounting hole (not shown) of the metal core 2 with the mounting hole 12 a of the lower cover 8 while aligning the metal core 2 with the mounting hole 12 a of the lower cover 8. Assemble it. In addition, the airbag device 3
0 is also assembled in advance.

The mounting bracket 38 is attached to each mounting seat 4.
The airbag device 30 is arranged on the steering wheel body 1 so that
The mounting bolt 26 temporarily fixed to 9 is pushed into the steering wheel body 1 side.

Then, the locking groove 27a of each mounting bolt 26
The hook portions 21a of the locking legs 21 are bent and detached from each other, and each mounting bolt 26 moves to the steering wheel body 1 side.

At this time, three ribs 22 radially provided on the inner peripheral surface of each temporary fixing portion 19 are respectively provided on the temporary fixing portion 1.
9 has a guide surface 22a parallel to the axial direction O,
The screw portion 2 of the mounting bolt 26 without rattling
The tip of 8 is smoothly guided to the screwing position of the end of the screw hole 38a of the airbag device 30 through the insertion hole 4d in the mounting seat 4 of the cored bar 2. So after that,
If the mounting bolt 26 is turned and tightened, the mounting bolt 26
Is screwed into the screw hole 38a, and the bolt head 27 is pressed against the periphery of the insertion hole 4d, so that the airbag device 30 can be easily attached to the steering wheel body 1.

Each of the temporary fixing portions 19 has an inner peripheral surface 20a.
In addition, even if the rib 22 having the guide surface 22a parallel to the axial direction O of the temporary fixing portion 19 is provided, since the ribs 22 are partial, the inner peripheral surface 20a other than the rib 22 is replaced with the base portion. By forming a tapered surface that extends from the side 19a to the tip side 19c, it is possible to minimize a decrease in the releasability of the temporary fixing portion 19 during injection molding. Note that the inner peripheral surface of the temporary fixing portion 19 is formed by a split die that moves downward at the time of release from the mold.

Therefore, in the lower cover 8 of the embodiment, the lowering of the releasability during molding is suppressed and the airbag device 3
0 can improve the mounting workability.

In the embodiment, the case where the number of the ribs 22 provided on the inner peripheral surface 20 of each temporary fixing portion 19 is three is shown.
The number of the ribs 22 may be two or more, preferably 3 to 5, as long as the mounting bolt 26 can be smoothly guided to the screwing position. The ratio is preferably 1% to 30% of the entire circumference of the inner peripheral surface 20a in consideration of a decrease in releasability. If it is less than 1%, the rib may be deformed when the mounting bolt 26 is pushed in, and if it exceeds 30%, the releasability is deteriorated.

Further, the length of these ribs 22 need not be provided over the entire length of the temporary fixing member 19,
Can be smoothly guided to the screwing position, if it is provided for the length from the temporary fixing position X until the tip of the screw portion 28 of the mounting bolt 26 is inserted into the inlet of the screw hole 38a of the airbag device 30. good.

[Brief description of the drawings]

FIG. 1 is a plan view of a steering wheel from which an airbag device according to an embodiment of the present invention is omitted, and shows a state before a mounting bolt is pushed.

FIG. 2 is a cross-sectional view of the steering wheel according to the embodiment, which corresponds to a portion II-II in FIG.

FIG. 3 is a cross-sectional view showing a state in which the airbag device of the embodiment is attached to a steering wheel body,
Corresponds to II-III sites.

FIG. 4 is a plan view of the lower cover of the embodiment, and a right half side is a plan view showing a state immediately after molding.

FIG. 5 is an enlarged view of a portion V in FIG.

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

FIG. 7 is a cross-sectional view showing a state where the mounting bolt of the embodiment is pushed in;

[Description of Signs] 1 ... Steering wheel main body, 8 ... Lower cover, 19 ... Temporary fixing part, 19a ... Original part side, 19c ... Tip side, 20a ... Inner peripheral surface, 21 ... Locking leg, 21a ... Hook part, 22 ... Rib, 22a ... Guide surface, 26 ... Mounting bolt, 27 ... Head, 27a ... Lock groove, 28 ... Screw part, 30 ... Airbag device, O ... Axial direction, W ... Steering wheel.

Claims (1)

[Claims] 1. A temporary fixing portion for temporarily fixing a mounting bolt for attaching the airbag device to a steering wheel body, made of synthetic resin covering a lower portion of a steering wheel provided with an airbag device. The stopping portion includes a locking leg having a hook portion protruding inwardly on the base portion side, and a front end side toward the steering wheel body side, and an inner circumferential surface from the base portion side to the front end side. The hook portion of the locking leg is locked in a locking groove provided on the outer periphery of the cylindrical head of the mounting bolt, and the screw portion of the mounting bolt is connected to the steering wheel. A lower cover of a steering wheel for temporarily fixing the mounting bolt toward a main body, wherein a head of the mounting bolt is attached to an inner peripheral surface of the temporary fixing portion from the temporary fixing position. To guide until note engagement position, said plurality of ribs having a direction parallel to the axial guide surface of the temporary fixing portion is, the lower cover of the steering wheel, characterized in that it is formed.