Land vehicles – Wheeled – Running gear
Reexamination Certificate
1998-11-25
2001-05-01
Culbreth, Eric (Department: 3611)
Land vehicles
Wheeled
Running gear
Reexamination Certificate
active
06224104
ABSTRACT:
This application claims the benefit of Japanese Application No. 9-347359 which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an impact-absorbing steering column device, and more specifically, to a technology to reduce the manufacturing cost, facilitate setting of impact-absorbing characteristics of the device, etc.
2. Related Background Art
When a car collides with another car, a building, or the like, the driver in some cases comes into a secondary collision due to inertia and suffers serious damage to his head or chest. Recently, cars and automobiles largely employ, in order to avoid such trouble, an impact-absorbing steering shaft or an impact-absorbing steering column device. An impact-absorbing steering shaft is generally arranged such that the length of a steering shaft on the steering wheel side is reduced when the driver comes into a secondary collision. For this arrangement, the steering shaft is divided into an outer shaft and an inner shaft, and these shafts are engaged with each other to be mutually slidable by serration, etc. An impact-absorbing steering column device is arranged, for example, such that a steering column moves forward together with a steering shaft when the driver comes into a secondary collision. For this arrangement, plastic pins are generally used for connecting a bracket fixed to the car body (a dashboard or the like) (hereinafter called the body-side bracket) with the steering column so that the pins are broken due to the impact load at the time of the secondary collision and causes the steering column to move forward.
Normally, the impact-absorbing steering column device is provided with an impact absorbing means between the body-side bracket and the steering column so as to gradually absorb the impact energy which the steering column moves forward. For example, Japanese Utility Model Application Laid-Open No. 5-75057 discloses such arrangement in which an impact energy absorbing member is interposed between an upper bracket for supporting an upper part of a steering column and the steering column and the impact energy absorbing member is elongated to be plastically deformed when the steering column moves forward. This impact energy absorbing member is formed by punching a steel plate into the form of a pantograph or a waveform, and the fore end of the impact energy absorbing member is welded to the steering column whereas the rear end thereof is locked by a pin inserted through the car body-side bracket. Also, in Japanese Patent Application Laid-Open No. 7-215221, there is disclosed an impact energy absorbing member formed of a band-shaped steel plate, as well as another impact energy member punched from a steel plate and has a pleated elongated portion. The band-shaped steel plate has one end secured to the body-side bracket (or the steering column) and is drawn to be deformed by a drawing portion which is formed on the steering column side (or the body-side bracket) when the steering column is moved forward.
In the above-mentioned impact-absorbing steering column device, since the impact energy absorbing member is made of a steel plate, it requires a great cost to produce a press metal mold for punching the member. Also, since the weight per unit area of the steel plate is large, if an impact absorbing stroke is made large, the whole weight of the steering device also becomes large. Also, if the impact energy absorbing member is made in the form of a pantograph or wave form, a large amount of waste material is generated when the impact energy absorbing member is punched, so as to bring about a very poor yield of material. For the steering device in which an impact energy absorbing member is welded to a steering column or the like, the process of assembling the steering device includes a welding work, which inevitably causes a decline of the assembling workability and deterioration of working environments. In addition, in a steering device of this type, it is desirable to set the impact absorbing characteristics freely, which, however, requires a great cost when the specifications are altered, because a press metal mold is used for punching the impact absorbing member.
SUMMARY OF THE INVENTION
The present invention was conceived taking the above circumstances into consideration, and an object of the invention is to provide an impact-absorbing steering column device which is adapted to reduce the manufacturing cost and to facilitate setting of the impact absorbing characteristics.
The present invention proposes, in order to solve the above-mentioned problems, an impact-absorbing steering column device comprising a steering column which supports a steering shaft to be rotatable, a body-side bracket which is secured to the body of a car and supports the steering column and allows the steering column to move when an impact load of not less than a predetermined value is applied thereon, and an impact energy absorbing means which is provided between the steering column and the body-side bracket so as to absorb the impact energy when the steering column is moved, wherein the impact energy absorbing means comprises an energy absorbing member which is produced from metallic wire and has a latch portion latched by the body-side bracket and a drawing portion which is formed on the steering column for drawing and deforming the energy absorbing member when the steering column is moved.
According to the present invention, when the steering column is released from the body-side bracket and moves forward, the energy absorbing member is drawn and deformed by the drawing portion of the steering column, so as to absorb the impact energy at that time. Also, the impact absorbing characteristics can be easily set by properly altering the form or size of the energy absorbing member with a bending die.
Also according to the present invention, there is provided an impact-absorbing steering column device which comprises a steering column for supporting a steering shaft to be rotatable, a bracket device secured to the body side for supporting the steering column, so as to release the supported state of the steering column to allow the steering column to move when an impact load of not less than a predetermined value is applied thereon, and an energy absorbing device provided between the bracket device and the steering column so as to absorb the impact energy when the steering column is moved because of the load of not less than the predetermined value. The energy absorbing device comprises: a metallic wire which consists of first and second portions extending substantially in parallel and a connection portion integrally continuous to the first and second portions, in which the first and second portions are respectively extended to non-restrained end portions through bent back portions formed substantially equidistant from the connection portion; a restraint portion which is secured to the car body for supporting the wire between the connection portion and the bent back portions so as to restrain the connection portion when the impact load is applied onto the wire; and a coupler which is secured to the steering column and is provided with a pin around which the bent back portions of the wire are passed and against which the bent back portions are born, whereby when the steering column is moved upon application of the impact load, said coupler is moved together with the steering column to move the wire by a predetermined distance through the pin so as to restrain the connection portion at the restraint portion, so that the first and second portions of the wire are drawn by the pin and are plastically deformed to absorb the impact load.
REFERENCES:
patent: 3262332 (1966-07-01), Wight
patent: 3373629 (1968-03-01), Wight et al.
patent: 3392599 (1968-07-01), White
patent: 4989898 (1991-02-01), Yamaguchi et al.
patent: 5425553 (1995-06-01), Yazane et al.
patent: 5562307 (1996-10-01), Connor
patent: 5595399 (1997-01-01), Fouquet et al.
patent: 5609364 (1997-03-01), Fouquet et al.
patent: 561591
Culbreth Eric
NSK Ltd.
Shriver J. Allen
Vorys Sater Seymour and Pease LLP
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