Tilt and telescopic steering system

Disclosed is a tilt-and-telescopic steering system having a guide bush, the system including an interior tube and an exterior tube which surround a steering shaft; a distance member integrally fixed to an outer peripheral surface of the exterior tube; tilt brackets assembled with an outer peripheral surface of the distance member so as to limit a movement angle in tilt operation; and a lever and a bolt which hold and release the tilt-and-telescopic system, wherein a through hole is formed in the exterior tube and the distance member which are disposed between an outer peripheral surface of the interior tube and an inner peripheral surface of the tilt brackets, wherein a guide bush is inserted in the through hole.

RELATED APPLICATION

This application claims convention priority to Korean patent application No. 2006-50827 filed on Jun. 7, 2006, the content of which is incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a tilt-and-telescopic steering system, and more particularly to a tilt-and-telescopic system including a guide bush, which is inserted through an exterior tube and a distance member and simultaneously holds the exterior tube and an interior tube, thereby increasing the fixing strength of the exterior tube and the interior tube when a lever is operated.

BACKGROUND OF THE INVENTION

In general, a vehicular steering column is installed in front of a driver's seat so that a rotational force of a steering wheel is transferred to a vehicle via a gear box. The vehicular steering column includes a tilt-and-telescopic system for controlling a location of a steering wheel depending on a physical condition of the driver.

In order to secure a tilt function for controlling a fixed angle of the steering wheel, the telescopic apparatus has two hollow pipes including one pipe inserted in the other pipe, so that they can extend and retract in an axial direction.

FIG. 1is a perspective view of a conventional steering column. The conventional steering column100includes a distance member120, an exterior tube130, an interior tube140, a bush150, an upper mounting bracket160, and a lower mounting bracket170.

The tilt apparatus is a mechanism for changing an angle of the steering wheel (not shown) by operating a lever180. The tilt operation can be easily performed due to a tilt spring110. The tilt spring110prevents the steering wheel from rapidly moving toward a lower direction due to gravity, and enables the driver to easily shift the steering wheel in an upper direction.

The distance member120is a mechanism for enabling the steering column100to extend and retract by the operation of the lever180. The distance member120includes the exterior tube130which is hollow and allows the interior tube140to slide therein and the interior tube140inserted in the exterior tube130and sliding therein.

Meanwhile, when the interior tube140slides in the axial direction thereof so as to control a displacement of the steering column, the bush150is inserted between an outer peripheral surface of the interior tube140and an inner peripheral surface of the exterior rube130in order to allowing the smooth sliding of the interior tube140.

Meanwhile, it is a recent tendency that an engine is set to have a low RPM (Revolution Per Minute) during idling of the vehicle, in order to improve fuel efficiency thereof. As the RPM of the idling decreases, the vibration of the engine shows a tendency to increase. However, such a problem can be remarkably lessened, because an engine mount of a rubber material, which fixes the engine in a vehicular body, absorbs a certain amount of vibration. However, in view of the steering system, it is necessary to increase the strength of the bush150so as to prevent the resonance of the steering system, which occurs at the low RPM while idling, and so as to keep a determined telescopic force when the lever180is held and released. Therefore, there are many problems in that the strength of the bush150increases under the structure that the bush150is inserted between the interior tube140and the exterior tube130.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a tilt-and-telescopic system including a guide bush, which is inserted through a exterior tube and a distance member and simultaneously holds the exterior tube and an interior tube, thereby increasing the fixing strength of the exterior tube and the interior tube when a lever is operated.

In accordance with an aspect of the present invention, there is provided a tilt-and-telescopic steering system including; an interior tube and an exterior tube enclosing a steering shaft; a distance member integrally fixed to an outer peripheral surface of the exterior tube; tilt brackets assembled with an outer peripheral surface of the distance member so as to limit a movement angle in tilt operation; and a lever and a bolt which fix and release the tilt-and-telescopic system, wherein a through hole is formed in the exterior tube and the distance member which are disposed between an outer peripheral surface of the interior tube and an inner peripheral surface of the tilt brackets, wherein a guide bush is inserted in the through hole.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, the same elements will be designated by the same reference numerals although they are shown in different drawings. Further, in the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 2is a perspective view of a tilt-and-telescopic system according the preferred embodiment of the present invention.

The tilt-and-telescopic system according to the preferred embodiment of the present invention includes an interior tube210, an exterior tube220, tilt brackets230, a lever240, and a distance member250. An end of the interior tube210is held in a vehicular body by a lower mounting bracket215, and the other end thereof is inserted in an inner peripheral surface of the exterior tube220.

The distance member250is integrally fixed in an outer peripheral surface of an end of the exterior tube220by welding, etc. A structure that the distance member250and the exterior tube220are integrally fixed in each other refers to an outer225. As shown in the accompanying drawings, the distance member250has a pipe-configuration and includes guide parts253at opposite sides of a lower outer peripheral surface of the exterior tube220. Each guide part253has a telescopic guide groove255formed therein.

Each tilt bracket230is fixed in the vehicular body integrally with an upper mounting bracket235, and has a tilt guide groove237formed in both sides thereof while facing each other. The tilt bracket230is disposed on both left and right sides of the distance member250, and the distance member250and each tilt bracket230are assembled with each other by a bolt260extending through telescopic guide grooves255and tilt guide grooves237.

An end of the bolt260has a lever240for rotating the bolt260, and the other end thereof has a fixed gear290and a movable gear295which are used for controlling a location of the steering wheel when a tilt function is performed. The structure configured as described above has a guide bush280for fixing the interior tube210in the exterior tube220when the lever is operated.

FIG. 3ais a partial perspective view of the tilt-and-telescopic system according to the preferred embodiment of the present invention.FIG. 3bis a perspective view of the guide bush according to the preferred embodiment of the present invention.

The outer225has a through hole310formed in both or one of a left side and a right side of the distance member250, in which each tilt bracket230and the distance member250make contact with each other, so that it is easy to control load when the lever240is operated. The through hole310has a rectangular configuration having a sectional shape of “T”. A central part of the through hole310in a vertical width direction thereof extends completely through the distance member250. Also, the through hole310has a fixing groove320, which is formed in upper and lower parts of the central part and has a predetermined depth. The guide bush280has a configuration having a sectional shape similar to “T”, and includes a protruding part. The guide bush280has a first contact surface330formed at the protruding part of the guide bush280and a second contact surface340formed at a non-protruding part of the guide bush280. It is preferable that the first contact surface330has a curvature equal to a curvature of the outer peripheral surface of the interior tube210, and the second contact surface340has a curvature equal to a curvature of the fixing groove320, so that the guide bush280can be tightly inserted in the through hole310and come into close contact with the outer peripheral surface of the inner tube210. Also, the guide bush280has the third contact surface350, which is a surface opposite to the surfaces having the protruding and non-protruding parts, having a flat shape so as to come into close contact with the tilt bracket237.

Therefore, when the lever240is held, the bolt260is locked so as to apply a pressure to the tilt bracket230, thereby applying the pressure to the guide bush280. As a result, the guide bush280presses the interior tube210as well as the outer225, so that the telescopic apparatus is fixed. At the same time, the fixed gear290is engaged with the movable gear295, so as to fix the tilt apparatus.

As described above, according to the present invention, the through hole is formed in the exterior tube and the distance member, and the guide bush is inserted in the through hole, thereby providing a strong coupling force when the lever is held. Therefore, there is an effect to restrict idle vibration occurring during stopping of the vehicle.

Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Accordingly, the scope of the invention is not to be limited by the above embodiments but by the claims and the equivalents thereof.