JPS642544B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steering wheel for a motor vehicle, and more particularly to an impact energy absorbing steering wheel.
U.S. Patent No. 1 for “Safety Steering Handle”
No. 3016764 describes a flexible steel armature that provides the necessary torsional stiffness to steer the vehicle while allowing axial movement of the rim under relatively low impact load conditions. A two-stage collapsible steering handle comprising a rim steering handle is disclosed. The armature progressively collapses under load to support the rim on an energy absorbing central structure structured and arranged to absorb much more impact energy than axial movement. be done.

Since the development of the steering wheel structure described in the aforementioned US patent, attempts have been made to substitute plastic materials for all-steel construction. A major advantage of the use of plastic materials is that weight savings are achieved which become increasingly significant as the demand for more fuel efficient vehicles increases in the market.
Prior art patents describing the advancement of an all-steel steering wheel structure toward an all-plastic steering wheel include U.S. Pat.
No. 3938404 and No. 4010658.

All of these prior art patent specifications disclose steering wheel structures that utilize composite structures, ie, steel and plastic materials. The present invention provides a steering wheel assembly in which the only major metal component is a metal hub for mounting the steering wheel to a steering shaft of a vehicle.

In a preferred embodiment of the invention, the energy absorbing steering wheel is mounted on a hub. The steering wheel is molded from high impact rated nylon and consists of a one-piece rim, spokes, and a thin-walled energy absorbing sleeve. The energy absorbing sleeve when viewed in plan has a substantially rectangular shape tapering in size from its upper end downwardly towards the hub. Each side wall of the sleeve has a generally arcuate shape that slopes inwardly toward the axis of rotation from the upper end to the lower end of the sleeve.

According to the present invention, the rim, spokes and energy absorbing sleeve, apart from the hub, are made of a homogeneous one-piece structure made from high impact elastic materials, reducing weight and manufacturing costs. It is possible. In addition, since the energy absorbing sleeve has a rectangular cross section with different sizes in the axial direction, the section modulus changes in the axial direction, resulting in a large amount of crushing when a relatively constant load is applied in the axial direction. It has become possible to absorb energy to a high degree.

Other objects, advantages and features of the invention will become apparent from the following description of the accompanying drawings.

In the accompanying drawings, a steering wheel embodying the invention is designated generally at 10. The steering wheel basically consists of a rim 11, spokes 12 and an energy absorbing sleeve 13, all of which are supported on a hub 14. The rim 11, spokes 12, and energy absorbing sleeve 13 are integrally molded from high impact rated nylon. No metal is included other than that contained within the hub 14.

As with the conventional steering wheel, rim 1
1 is arranged in coaxial relation to the hub 14 and the plane of said rim is arranged axially from said hub.

The rim 11, as shown in FIG.
A plurality of small pockets 15 made using cores are provided on the lower surface 16. First of all, these pockets reduce the weight of the rim and therefore of the steering wheel. Second, the pocket controls the stiffness of the rim. In an energy-absorbing steering wheel, it is highly desirable for the rim structure to have a significant amount of flexibility under high thoracic impact loads during a frontal vehicle crash so as to provide full thoracic contact. Furthermore, this rim structure must have sufficient rigidity for the steering function and to act as a grab bar.

In FIGS. 4 and 6, the spokes 12 are also hollowed out. Recessed pockets 17 extend longitudinally of the spokes and serve to reduce the weight of the steering wheel and to limit the stiffness of the spoke and rim structure.

The energy absorbing sleeve 13 when viewed in plan view as in FIG. 1 has a substantially rectangular shape. The sleeve 13 tapers in size from the top to the bottom. That is, if the planes were parallel and axially spaced from the top to the bottom of the sleeve, the area of the rectangle in each plane would be less than the area of the plane above it. The sleeve 13 is of thin-walled construction, and each of the four walls has a pointed arch shape from top to bottom. At its upper end, the sleeve 13
is reinforced on the outside by a thick-walled rectangular annular body 18 of substantially rectangular cross section, on which the spokes 12 are integrally made in a cantilevered manner. Annular body 1
8 is also provided with a plurality of lightened weight-reducing pockets 19 extending inwardly from its upper surface 21.

The side wall of the sleeve 13 terminates in an inwardly curved flat base portion 22 centered on an opening 23 for receiving the hub 14. The hub 14 has an impact extruded cylindrical body 24 having a radially extending annular flange 25. Flange 25 has integral aluminum half-tubular studs 26 in a circular array.
The studs 26 project through a pair of mating holes provided in the base portion 22 and the steel plate or die 27 and are spun fixed to fasten the plastic material between the flange 25 and the plate 27. has been done. The steel plate 27 is the base portion 22 of the sleeve.
Increasing the contact area with the plastic, especially for rivets 2.
6 helps reduce stress concentrations.

The upper half of the hub 14 is provided with an internal spline 28 for receiving the splined upper end of a vehicle steering shaft (not shown).

Preferably, this steering wheel 10 has four spokes 12, which in the normal central position of the steering wheel as shown in FIG.
are shaped to extend outwardly from the upper corner portion 29 to the short side of the rectangular annular body 18 of the sleeve 13 in mutual alignment to the rim 11 . The lower two spokes 12b extend in a downwardly angular direction from the lower corner portion 31 of the annular body 18. This particular arrangement of spokes on each side of the steering wheel is conventional and reduces stiffness of the rim while allowing the use of spokes that allow a low rate of deflection during bending out of the plane of the unstressed steering wheel. considerably increases. A low rate of spoke deflection is desirable to protect personnel of the vehicle in the event of a head-on collision involving the vehicle. That is, when the front surface of the driver's abdominal area hits the rim of the steering wheel, the spokes will not produce an excessive reaction force and the rim will flex until the chest area contacts the large surface area of the hub cover 32. I forgive you. If the force applied to the hub cover 32 is sufficiently large, the energy absorbing sleeve 1
3 and crushes it.

Hub cover 32 is molded from a suitably colored, rigid plastic into a substantially rectangular shape. cover 3
2 are hollow and have appropriate intersecting ribs 33 to provide the required stiffness while minimizing weight.

The cover 32 is held in place by suitable tapping screws 34 disposed around the entire circumference.

High impact rated nylon is selected for virtually all plastic steering handles because this type of nylon has physical properties that eliminate the need for a nylon coating. When manufacturing plastic steering handles from polycarbonate material, a second molding operation is required since the polycarbonate is preferably coated with polyvinyl chloride plastic (PVC). polycarbonate and
Additional benefits of nylon construction when compared to PVC composites include (1) the lower specific gravity of nylon and (2) rims and spokes that become filled with PVC in the second molding operation. There is a considerable weight reduction as a result of the elimination of plastic filling the hollow pockets. Since the nylon is not coated with non-structural materials, especially PVC which does not add rigidity to the structure, the nylon can be distributed within the cross-section of the rim and spokes to obtain an increased section modulus. This beneficial effect tends to offset the lower bending modulus of nylon compared to materials such as polycarbonate.

Although preferred embodiments of the present invention have been disclosed above, it goes without saying that various changes can be made without departing from the scope of the present invention.

[Brief explanation of the drawing]

1 is a plan view of a steering handle assembly embodying the principles of the present invention; FIG. 2 is an enlarged sectional view taken substantially along line 2--2 in FIG. 1; and FIG.
4 is a bottom plan view of a fragment of the steering wheel assembly; FIG. 5 is a view in the direction of arrow 5 of FIG. 4; FIG. 6 is a view of FIG. FIG. 2 is a cross-sectional view taken along the - line and viewed in the direction of the arrow. 10... Steering handle, 11... Rim, 1
2...Spoke, 13...Energy absorption sleeve, 14...Hub, 15...Pocket, 17...
Pocket, 18...Thick-walled rectangular annular body, 19...
Pocket, 22... Base portion, 24... Cylindrical body, 25... Flange, 26... Stud, 27...
Steel plate, 28...spline.

Claims (1)

[Scope of Claims] 1. A steering handle mounted on a hub for rotational movement around a rotation axis, wherein the steering handle is coaxially connected to one end of an axially extending energy absorbing sleeve via a plurality of spokes. a rim attached to the rim, the spokes extending outwardly from one end of the energy absorbing sleeve to the rim, the other end of the energy absorbing sleeve being coupled to the hub; and the energy absorbing sleeve is of a homogeneous one-piece construction made of a high impact modulus material, the energy absorbing sleeve having a substantially rectangular shape at the height connecting the spokes, and having a length relative to the length of the energy absorbing sleeve. any transverse plane taken perpendicular to the axis of rotation up to a height in contact with the hub is maintained in a substantially rectangular shape, and the hub has a width dimension not exceeding the width of the energy absorbing sleeve in any radial direction from the axis of rotation. wherein the energy absorbing sleeve has thin sidewalls, each sidewall having a generally arcuate shape that slopes inwardly toward the axis of rotation from one end of the energy absorbing sleeve to the other end, thereby The cross-sectional area of the energy-absorbing sleeve decreases from the one end to the other end, and the energy-absorbing sleeve absorbs energy to a high degree against axial forces, so that a large amount of crushing can be generated with a relatively constant load. An energy-absorbing steering wheel featuring 2. The rim and the spokes are characterized in that they have a circumferentially and longitudinally extending rib shape on the lower surface of each of the rims and spokes in order to reduce weight and provide the desired elasticity in the direction of the axis of rotation of the energy-absorbing steering wheel. A steering handle according to claim 1. 3. The energy-absorbing sleeve has a rectangular annular body with spokes cantilevered at its upper end, said rectangular annular body having side walls, and said side walls have a cross-sectional width and a depth that are smaller than those of said energy-absorbing sleeve. 3. An energy-absorbing steering handle according to claim 1 or 2, characterized in that it is substantially greater than the thickness of the side wall.