JPS6235640Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an energy-absorbing steering shaft.

A steering shaft of a vehicle includes a shaft body that connects the steering rotation movement of a steering wheel to a rack and pinion mechanism, a column that surrounds and supports the shaft body, and a column cover that covers the outer periphery of the shaft body.

An energy absorption type steering shaft has been proposed, in which the shaft body and column move in the axial direction and absorb the collision energy when a shock of more than a predetermined value is applied through the steering wheel during a vehicle collision. Ru.

The present invention was made to improve such an energy-absorbing steering shaft, and its purpose is to provide a transmission section that transmits rotational force by squeezing a part of the first member made of pipe material. A part of a second member having substantially the same cross section is fitted thereto, and a part of the second member close to the large diameter part of the first member is provided with an axial friction resistance part. The second member and the first member are made to slide in the axial direction against the frictional resistance part by a predetermined axial load or more at the time of a collision, and after sliding for a predetermined stroke, the frictional resistance part is moved to the first To provide a steering shaft in which the large-diameter portion of the first member is exposed, after which both members can be smoothly and quickly slid in the axial direction, and effective energy absorption by air bags can be achieved.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, before explaining the present invention, the premise of the structure will be explained.

FIG. 1 is a longitudinal cross-sectional view of the steering area. A steering wheel 2 is provided on the driver's seat side of an instrument panel 1, and the steering wheel 2 is connected to one end of the steering shaft body 5 via a bracket 4 having a space 3 inside. connected to
The main body 5 consists of a tip member 6, a pipe-shaped intermediate member 7, and a base member 8 having a pinion 9 at the base end. The main body 5 is surrounded by a column 10, and a column 1
0 consists of two members 11 and 12 that are divided in the axial direction, and the members 11 and 12 slide in the axial direction under a predetermined axial load or more and perform an energy absorption function. The member 8 also slides in the axial direction under a predetermined axial load or more, and performs an energy absorbing action.

In the embodiment, a high-pressure gas container 13 is attached to the outer 12 of the column 10 so that it can be opened by a starter 14, and a gas container is inserted into the tip member 6 of the main body 5 through a through hole 6a. A chamber 6b communicating with the side is provided, and a nozzle 6c is further provided at the tip to communicate with the inside of the chamber 3. An air bag 15 is folded and stored in the chamber 3, and a fragile portion 4b is provided around the ceiling 4a of the bracket 4. is provided, and when the bag is inflated and deployed, the ceiling part 4a forming the pad is torn, and the bag is inflated and deployed in front of the driver. Such an air bag device activates the activation device 14 when the collision is greater than a predetermined level, opens the container 13, sucks in high pressure gas and supplementary air, and supplies the chamber 3 through the systems 6a, 6b, and 6c.
The bag 15 is inflated and deployed.

In the above, the steering shaft body 5 is configured as shown in FIGS. 2 to 4.

A pinched portion 16 is formed over a predetermined length at the base of the pipe-shaped intermediate member 7, that is, the portion on the front side of the vehicle.
The pinching part 16 has a cross section that transmits rotational force, for example, a rectangular pipe shape, the squeezing part 16 is a transmission part, and the pinching part 16 is provided a predetermined axial length from the base end 16a,
The diameter expands in a tapered shape from the tip 16b, and the intermediate member 7
The portion after the intermediate portion 7a has a circular cross section as shown in FIG.

The base member 8 is formed of, for example, a solid material, and its cross section fits into the squeezed portion 16 of the intermediate member 7 described above,
The base member 8 has a rectangular shape so as to receive rotational force, and the tip 8a of the base member 8, that is, the portion on the rear side of the vehicle, is fitted into the pinching part 16, and the tip 8b of the tip 8a is the tip 16b of the pinching part 16 in the normal state. Facing the inner diameter. A friction resistance portion 17 made of a synthetic resin injector or coating having a high frictional coefficient is formed around the tip of the tip portion 8a of the base member 8, and the portion 17 is formed with a coating of polyacetal, for example.
7, a portion with high frictional resistance is formed between the pinched portion 16 and the inner diameter portion. The portion 17 has a predetermined length in the axial direction, and is formed, for example, at a portion located about 10 mm toward the front of the vehicle from the tip 8b. This frictional resistance part 1
A radial through hole 18 is provided in the axially intermediate portion of 7,
In addition, radial through holes 19, 19 are provided in the squeezed portion 16 corresponding to the hole 18 in the normal state, and the through holes 18,
A pin 20 is passed through the pins 19 and 19, and the members 7 and 8 are connected by the pin 20 through frictional engagement.

In the above, the rotational force of the intermediate member 7 is transmitted to the base member 8 via the pinching portion 16 and the tip portion 8a, and is transmitted to a rack (not shown) that rotates and meshes with the pinion 9 described above, and is then transmitted to the rack (not shown) that rotates and meshes with the pinion 9 described above. I do.

By the way, at the time of a vehicle collision, a load acts on the steering shaft body 5 in the axial direction, and a load acts on the intermediate member 7 with the base member 8 fixed in the axial direction toward the front of the vehicle.If the load exceeds a predetermined value, the pin 20 is Shear,
The axial load is received by the frictional resistance portion 17. As a result, the axial sliding between the members 7 and 8 is made gentle due to friction, and the frictional resistance part 1 slides while absorbing energy, for example, at a position moved by 10 mm.
7 escapes from the tip of the pinching part 16 and reaches the large diameter part, after which it slides smoothly to reduce the axial stroke and absorb energy. This is shown in FIG. 5, and as a result, there is resistance up to a predetermined stroke at the initial stage of a collision, and then it becomes free, making it possible to effectively absorb energy and cushion the impact.

Next, the present invention will be explained.

6 to 8 show embodiments of the present invention, in which the intermediate member 107 connected to the steering wheel side is solid, and the base member 108 connected to the steering mechanism is pipe-shaped.

A large diameter portion 1 of a predetermined length is provided at the tip of the intermediate member 107.
07a, while the base member 108 has a sufficiently large diameter, and a pinched portion 116 corresponding to the large diameter portion 107a is formed at the rear of the base member 108. The inner diameter part of the pinching part 116 has a slightly larger diameter from the tip to the middle part than the large diameter part 107a, and a bearing part 117 which is made of synthetic resin or the like and serves as a friction resistance part is formed at the tip to the middle part.
7a tightly fits into the bearing portion 117. Squeezing part 11
The rear part 116a behind the bearing part 117 of 6 is the large diameter part 1
07a so that it fits tightly.

A plurality of holes 119, for example, two holes 119 are provided in the squeeze portion 116 in a direction perpendicular to the axial direction and spaced apart from each other.
A plurality of holes 119 are provided on the circumference at intervals in the circumferential direction, and on the other hand, the same number and the same positions of recesses 107b shaped to accommodate the rivet heads are provided around the tip of the intermediate member 107.
The pin portion 120 is formed by aligning the hole 119 and the recess 107b and filling the space with metal or synthetic resin.
Thereby, the intermediate member 107 and the base member 108 are configured to transmit motion in the rotational direction.

FIG. 6 shows a normal state, and if the member 108 side is the fixed side, an axial load acts on the member 107 at the time of collision, and as a result, the pin portion 120 is sheared on the hole 119 side and the recess 107b side. The member 107 slides in the axial direction within the inner diameter portion of the pinching portion 116 as shown in FIG. 7, and this sliding is made gentle due to the friction of the bearing portion 117, but after passing this portion, the tip portion as shown in FIG. The large diameter portion 107a is the large diameter portion 10 of the base member 108.
On the other hand, the small diameter portion 107c of the intermediate member 107 faces the inner diameter portion of the squeezed portion 116 having a larger diameter, and thereafter slides in the axial direction without any resistance.

In this way, the sliding movement is gentle at the beginning of the stroke, but the sliding movement is rapid and smooth after passing the bearing part. Therefore, even when the air bag is inflated and deployed, the steering shaft does not provide resistance, and the pressure of the air bag can be prevented from acting on the driver as a reaction force.

As is clear from the above, according to the present invention, there is resistance during the initial stroke at the time of a collision, and after that there is no resistance and a loose state is reached, so even if the airbag expands and deploys, the steering shaft will still provide resistance. This prevents the pressure of the air bag from acting on the driver as a reaction force, and therefore allows the air bag to function effectively.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a vertical cross-sectional side view of the steering area showing the underlying structure, FIG. 2 is a vertical cross-sectional view of the main parts of the steering shaft, and FIGS. 3 and 4. 2 is a sectional view taken along lines 3-3 and 4-4, FIG. 5 is a view similar to FIG. 2 in an energy absorption state, and FIGS. 6 to 8 show main parts of an embodiment of the present invention. FIG. In addition, in the drawing, 107 is a solid member, 107a is a large diameter part, 108 is a pipe-shaped member, 116 is a squeezed part,
117 is a friction resistance section.

Claims (1)

[Scope of Claim for Utility Model Registration] A steering shaft connected to a steering wheel that stores an air bag in the center that inflates and deploys in front of the driver in the event of a collision, and comprises a pipe-shaped member and a solid member divided into front and rear parts. , forming a squeezed part with a small diameter on the inner periphery at one end of the pipe-like member, and forming a large diameter part with a large diameter on the outer periphery at one end of the solid member, and inserting the large diameter part into the squeezed part. It is characterized in that it is capable of transmitting rotational force and is fitted so as to be able to slide in the axial direction, and that a friction resistance part is interposed between the inner periphery of the squeezed part and the outer periphery of the large diameter part. steering shaft.