KR20040037403A - collapse type steering shaft - Google Patents

Abstract

PURPOSE: A steering shaft for absorbing shock is provided to keep stable support load, and to reduce the deviation of the support load of each product by absorbing shock with discharging fluid between an upper shaft and a lower shaft properly. CONSTITUTION: A shock absorbing steering shaft is composed of a lower shaft(1) having a hollow cylinder; an upper shaft(5) having a piston(7) inserted to the hollow cylinder of the lower shaft; a restricting unit constraining the longitudinal movement of the lower shaft and the upper shaft; fluid charged in the space between the piston and the hollow cylinder; and a valve unit controlling discharge of fluid. The hollow cylinder of the lower shaft and the piston of the upper shaft are fixed by plastic molding(9). The plastic molding is broken by shock from the upper shaft at a collision, and shock is absorbed and stable support load is generated by discharging fluid with moving the piston to the hollow cylinder.

Description

Shock absorbing steering shaft {collapse type steering shaft}

The present invention relates to a shock absorbing steering shaft that is capable of absorbing a shock received by the driver while moving forward while reducing its overall length in the event of a vehicle accident.

1 and 2 show a conventional shock absorbing steering column. The steering shaft has a lower shaft 100 and an upper shaft 102 connected to each other by a plastic molding 104. If this is damaged, the lower shaft 100 enters the inside of the upper shaft 102 so that the overall length is reduced, and the outer tube 106 and the upper tube 108 are reduced in length as described above. When overlapped with each other when coupled to support the load by friction, the upper tube 108 is fixed to the cowl cross member by the upper bracket 110, the upper bracket 110 as described above When the length of the steering shaft is shortened, as shown in FIG. 3, the curling plate 112 is deformed to absorb shocks.

That is, when an impact force is applied from the steering wheel side, the plastic molding 104 is broken and the length of the steering shaft can be reduced, and at this time, the friction force generated between the lower tube 106 and the upper tube 108. And, to absorb the shock applied by the deformation force generated by the upper bracket 110 and the curling plate 112.

By the way, the shock absorbing steering column as described above, although the frictional force between the lower tube 106 and the upper tube 108, which plays a major role in absorbing the impact, can support a relatively large load due to the maximum static friction at the initial stage of friction. Once the relative movement between the lower tube 106 and the upper tube 108 begins, the frictional force is greatly reduced and the inertial force acts so that the load that can be supported as shown in FIG. 4 varies greatly over time. In addition, since the support load of the steering column in this manner is greatly different for each steering column manufactured for the above structural reasons and is not easy to manage, the support load provided by each steering column is significantly different. There is this.

Accordingly, the present invention has been made to solve the problems described above, it is possible to continuously provide a suitable support load that can absorb the impact of the driver in a stable state, significantly reducing the deviation of the support load for each product The purpose is to provide a shock-absorbing steering shaft that can be used.

1 is a view showing a conventional general shock absorbing steering column,

Figure 2 is a cross-sectional view showing the structure of the shock absorbing steering column of Figure 1,

3 is a view for explaining the shock absorbing structure of the upper bracket

4 is a graph showing a shock absorbing performance according to the prior art, showing a change in the supporting load over time,

5 is a view illustrating a structure of an impact absorbing steering shaft according to the present invention, which shows a state before contraction;

6 is a view illustrating a state in which the steering shaft of FIG. 5 is contracted;

FIG. 7 is a graph illustrating a shock absorbing performance of the shock absorbing steering shaft according to the present invention and showing a change in support load over time.

<Brief description of symbols for the main parts of the drawings>

One; Lower shaft 3; Hollow Cylinder

5; Upper shaft 7; piston

9; Plastic molding 11; Fluid

15; Valve body 17; Valve piston

19; Spring 21; Discharge path

23; Section reduction section 25; Stopper Block

27; Stopper rod

The present invention, the shock absorbing steering shaft for achieving the above object is a lower shaft having a hollow cylinder;

An upper shaft having a piston inserted into the hollow cylinder of the lower shaft;

Limiting means for limiting mutual longitudinal movement of the lower shaft and the upper shaft;

A fluid filled in a space formed by the piston and the hollow cylinder;

Characterized in that the valve means for controlling the discharge state of the fluid.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

5 is a view illustrating a structure of an impact absorbing steering shaft according to the present invention, in which the illustrated state is a state in which steering operation is normally performed before an accident occurs.

In the overall configuration, the lower shaft 1 has a hollow cylinder 3, the upper shaft 5 has a piston 7 inserted into the hollow cylinder 3, and the lower shaft 1 Between the upper shaft 5 and the upper shaft 5, a plastic molding 9, which is a limiting means for restricting mutual longitudinal movements, is installed through the lower shaft 1 and the piston 7 of the upper shaft.

The fluid 11 is filled in the space between the hollow cylinder 3 of the lower shaft fixed by the plastic molding 9 and the piston 7 of the upper shaft as described above, and the lower shaft 1 of the fluid Valve means for controlling the discharge state is provided.

Here, the valve means is the fluid 11 at an appropriate speed if the plastic molding (9) is damaged by the impact applied from the upper shaft (5) in the event of accident and the piston (7) proceeds inside the hollow cylinder (3) To absorb the shock and to stably generate the proper supporting load.

In this embodiment, the valve means is inserted into the hollow cylinder (3) has a valve body (15) having an opening (13) towards the upper shaft (5), and the lower shaft (1) in the valve body (15) Valve piston 17, which is perturbably installed in the longitudinal direction of the &lt; RTI ID = 0.0 &gt;), &lt; / RTI &gt; Stopper means for limiting the range of movement, and the lower shaft 1 and the valve body so that the valve piston 17 is discharged to the lower shaft 1 to discharge the fluid to the outside of the lower shaft 1. A discharge passage 21 formed through the 15 was configured.

In addition, the discharge passage 21 may be discharged to the outside of the lower shaft 1 as it is, but in this embodiment, the fluid discharged to the outside of the lower shaft 1 is received inside the hollow cylinder 3 of the lower shaft again. In order to connect the discharge passage 21 into the hollow cylinder (3) of the lower shaft behind the piston (7) of the upper shaft (5), the upper shaft (5) has a cross section behind the piston (7) The reduction unit 23 is provided to form an accommodation space for accommodating the fluid 11 discharged through the discharge passage 21.

On the other hand, the stopper means is composed of a stopper rod 27 having one end fixed to the valve body 15 and a stopper block 25 formed at the other end, and serves to guide linear movement of the valve piston 17. It was made.

Referring to the operation of the present invention configured as described above are as follows.

First, in the state as shown in FIG. 5, the steering operation force of the driver is normally transmitted from the upper shaft 5 to the gear box through the plastic molding 9 and the lower shaft 1 as a state before an accident occurs. Steering operation is made.

When an accident occurs and the driver's body hits the steering wheel and the impact is applied, the plastic molding 9 is broken and the upper shaft 5 is inserted into the lower shaft 1 to absorb the driver's shock. Do it.

At this time, when the upper shaft 5 proceeds to the inside of the lower shaft 1, the piston 7 pressurizes the fluid, and the pressure of the fluid causes the valve piston 17 to move to the spring 19. To overcome the force and move toward the lower shaft (1) to allow the discharge passage (21) to open.

Accordingly, the fluid 11 that has been filled between the piston 7 and the hollow cylinder 3 of the lower shaft exits through the discharge passage 21 as shown in FIG. 6 and is lowered behind the piston 7. It is sent into the hollow cylinder (3) of the shaft.

At this time, the speed at which the fluid 11 exits through the discharge passage 21 controls the speed at which the upper shaft 5 enters into the lower shaft 1, the diameter of the discharge passage 21 By controlling the viscosity of the fluid it is possible to control the speed at which the upper shaft (5) moves.

At present, since adjusting the speed of the discharged fluid as described above is possible to adjust a very precise level at a technically low cost, by adjusting the speed of the discharged fluid, the shock absorbing steering shaft is shown in FIG. 7. As shown in the drawing, more accurate and appropriate support loads can be exerted in a constant state over time.

Of course, the shock-absorbing steering shaft of the structure as described above is greatly reduced the deviation for each product for the same reason, it is possible to easily produce a certain level of the product has the effect of improving the mass production.

Proper support load that can absorb the driver's shock can be continuously provided in a stable state, and mass production can be improved by remarkably reducing the deviation of the support load for each product.

Claims (5)

A lower shaft having a hollow cylinder; An upper shaft having a piston inserted into the hollow cylinder of the lower shaft; Limiting means for limiting mutual longitudinal movement of the lower shaft and the upper shaft; A fluid filled in a space formed by the piston and the hollow cylinder; Valve means for controlling a discharge state of the fluid; Shock-absorbing steering shaft, characterized in that consisting of. The method of claim 1, wherein the limiting means Shock absorbing steering shaft, characterized in that consisting of a plastic molding installed through the upper shaft and the lower shaft. The method of claim 1, wherein the valve means A valve body inserted into the hollow cylinder and having an opening facing the upper shaft; A valve piston installed in the valve body so as to perturb in the longitudinal direction of the lower shaft; A spring holding the valve piston toward the upper shaft; Stopper means for limiting a range in which the valve piston is moved toward the upper shaft; A discharge flow passage formed through the lower shaft and the valve body to discharge the fluid to the outside of the lower shaft by moving the valve piston toward the lower shaft; Shock-absorbing steering shaft, characterized in that consisting of. The method of claim 3, The discharge passage is connected to the inside of the hollow cylinder of the lower shaft behind the piston of the upper shaft; The upper shaft has a cross-sectional reduction portion at the rear of the piston to form a receiving space for accommodating the fluid discharged through the discharge passage Shock absorbing steering shaft characterized in that. The method of claim 3, The stopper means is shock-absorbing steering shaft, characterized in that the end is fixed to the valve body and the other end is composed of a stopper rod formed with a stopper block.