Land vehicles – Wheeled – Running gear
Reexamination Certificate
2000-02-17
2002-04-30
Mai, Lanna (Department: 3619)
Land vehicles
Wheeled
Running gear
C188S371000
Reexamination Certificate
active
06378903
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a shock absorbing apparatus for a steering column which is particularly capable of improving the capability of absorbing an initial shock in a shock absorbing structure which, during the occurrence of a colliding accident of a vehicle, damps a shock, protects a driver, and ensures safety when the driver hits against a steering wheel as a reaction of the collision.
2. Description of the Related Art
A shock absorbing mechanism which, during a collision of a vehicle, absorbs energy occurring when the driver hits against the steering wheel as its reaction, and which damps the shock to protect the driver is conventionally incorporated in the vicinity of a steering column for supporting a steering shaft. Various such shock absorbing mechanisms have been developed, and many of them have been adopted in practice.
As a shock absorbing mechanism of this kind which is widely adopted, there is a type in which a column bracket for mounting the steering column is mounted at a predetermined position in a vehicle body in such a manner as to be movable in the back-and-forth direction. The moving operation of the column bracket is effected by an impact occurring when, during the occurrence of a collision, the driver hits against the steering wheel as a reaction of the collision. A mechanism for imparting resistance to the moving operation is provided at a connecting portion between the column bracket and the mounting portion so as to damp the shock and gradually diminish the force with which the column bracket moves.
The shock damping performance is substantially determined by the relative magnitude of the resistance during the moving operation of the column bracket. As a basic structure of this mechanism, while fixing members for connecting and fixing the column bracket in a predetermined position and mounted portions of the column bracket mounted in a predetermined position cause each other to undergo plastic deformation, and the impact energy is absorbed in their deformation process.
Accordingly, if the mounted portions of the column bracket are provided with shapes that allow deformation to take place easily, the response to the impact can be made sensitive. On the other hand, however, the amount of absorption of the impact energy becomes small, so that such a structure is unsuitable for a large impact. In contrast, if the mounted portions of the column bracket are provided with shapes that make it difficult for deformation to take place easily, the response to the impact becomes less sensitive, and it is difficult to respond to a small impact. On the other hand, however, the amount of absorption of the impact energy becomes large, so that such a structure is suitable for a large impact.
The impact which occurs in a collision of a vehicle changes in correspondence with the relative magnitude of the impact, but the shock absorbing mechanism must be able to exhibit satisfactory response to the impact whether it is large or small. In addition, the initial impact during the occurrence of a collision is very large, and the shock absorbing performance depends largely on whether or not the energy of the initial impact can be absorbed satisfactorily.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a shock absorbing apparatus for a steering column which improves the capability of absorbing an initial shock in the shock absorbing structure which, during the occurrence of a colliding accident of a vehicle, damps a shock, protects the driver, and ensures safety when the driver hits against the steering wheel as a reaction of the collision.
To this end, in accordance with a first aspect of the invention, there is provided a shock absorbing apparatus for a steering column, comprising: a sliding capsule having a collar portion fixed immovably to a vehicle body; and a column bracket having a shock absorbing hole which is elongated in a longitudinal direction of a steering column and in which a fixing through-hole portion on one end side of the elongated hole, a first shock absorbing portion having a shaft-like member in a vicinity of the fixing through-hole portion, and a second shock absorbing portion having a crushable inner peripheral edge at a side edge of the elongated hole are substantially continuously formed in the longitudinal direction, wherein, during a collision, the collar portion bends the shaft-like member and crushes the second shock absorbing portion to thereby absorb colliding energy.
In the above-described first aspect of the invention, the shock occurring during the collision can be absorbed in two stages. Particularly with respect to the impact of the initial collision in the first stage, it is possible to absorb the impact as the collar portion of the sliding capsule bends the shaft-like member by means of bending moment, with the result that the initial impact which is most intense can be satisfactorily alleviated. Subsequently, the impact energy can be gradually absorbed by the second shock absorbing portion.
In accordance with the above-described first aspect of the invention, the shock absorbing characteristic is improved at the time when the driver hits against the steering wheel during such as a collision of the vehicle, and the installation and adjustment of the shock absorbing apparatus for a steering column can be made simple, thereby overcoming the above-described problems of the conventional art.
In accordance with a second aspect of the invention, there is provided a shock absorbing apparatus for a steering column, comprising: a column bracket having a shock absorbing hole which is elongated in a longitudinal direction of a steering column and in which a fixing through-hole portion, a first shock absorbing portion, and a second shock absorbing portion are formed in that order from a forward side of a vehicle body, the first shock absorbing portion having a shaft-like member which can be bent by the collar portion, the second shock absorbing portion being formed in a shape of an elongated hole and having at least one of widthwise inner peripheral edges formed as a crushable inner peripheral edge; a sliding capsule having a collar portion insertable in the fixing through-hole portion of the column bracket and a resiliently supporting portion for resiliently pressing and supporting the column bracket; and a third shock absorbing portion formed as a resilient sliding friction mechanism in which the sliding capsule resiliently supports a laterally proximate portion of the shock absorbing hole by means of the resiliently supporting portion along the elongated shape formed by the first shock absorbing portion and the second shock absorbing portion, wherein the sliding capsule is immovable with respect to the vehicle body and resiliently supports the column bracket.
In the above-described second aspect of the invention, advantages are offered in that, firstly, it is possible to improve the shock alleviating capability during the collision, and that, secondly, it is possible to simplify the structure.
To give a more detailed description of the above-described advantages, the fixing through-hole portion, the first shock absorbing portion, and the second shock absorbing portion are formed in the shock absorbing hole. The first shock absorbing portion is made bendable by relative collision with the collar portion. Namely, as the collar portion collides against the shaft-like member due to the impact of the collision, the collar portion bends the shaft-like member
4
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by means of bending moment, and the initial intense shock is absorbed in that bending process.
Further, after the shaft-like member is bent by the collar portion, the collar portion moves to the second shock absorbing portion, and the impact energy is absorbed by the second shock absorbing portion. Further, in addition to the absorption of impact energy by the first shock absorbing portion and the second shock absorbing portion, the impact energy absorption can be concurrently effected by the th
Fujiu Isao
Hirooka Koji
Yabutsuka Mitsuo
Yokota Norihiko
Buchanan Christopher
Kabushiki Kaisha Yamada Seisakusho
Lowe Hauptman Gilman & Berner
Mai Lanna
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