JPH02216360A - Energy absorbing steering device - Google Patents

Abstract

PURPOSE:To improve a shock absorbing effect obtaining the shock absorbing characteristic of two steps by providing a ball, having a shock absorbing load different from each other, to be arranged over two layers between outer and inner tubes in a steering column. CONSTITUTION:A collision accident takes place in a vehicle, when a driver secondarily collides against a steering wheel 2, an outer tube 4 is moved in the axial direction for an inner tube 5, in a steering column 3 rotatably inserting and holding a steering shaft 1. Here the steering column interposes between the above described tubes 4, 5 an intermediate tube 6 while press fits between all the tubes 4 to 6 a plurality of the first and second balls 7, 8, respectively. And the second ball 8 is set in its shock absorbing load small than that of the first ball 7. Thus successively replacing each ball 7, 8, the ball, while it gives a streak to each tube 4, 5, is rolled absorbing shock energy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an energy absorbing steering device for absorbing impact energy caused by a collision between a driver and a steering wheel.

[Conventional technology]

As an example of an energy-absorbing steering device, as described in Japanese Utility Model Publication No. 53-45194, a steering column tube is composed of an outer tube and an inner tube that can be freely inserted and removed from each other, and a plurality of balls are held in the gap between the two tubes. It is known to have a holding cylinder arranged in the same manner as shown in FIG.

The diameter of the ball is set larger than the wall thickness of the holding cylinder and larger than the gap between the outer tube and the inner tube.

When the driver collides with the steering wheel, the impact force is transmitted to the outer tube, and the outer tube moves relative to the inner tube in the axial direction. At this time, the ball rolls against the outer tube or the inner tube while leaving scratches, so that impact energy is effectively absorbed.

[Problem to be solved by the invention]

In the case of the steering device having the above structure, since only one layer of balls is disposed between the outer tube and the inner tube, the characteristics of the shock absorption load with respect to the movement stroke of the outer tube are as shown in FIG. In this case, if the impact absorption load W1 is set high by increasing the depth of the ball's bite into the tube, there is a problem in that even a relatively small impact causes a large shock to the driver. On the other hand, by reducing the biting depth, the impact absorption load W
If 1 is set low, the shock applied to the driver can be alleviated, but on the other hand, a sufficient energy absorption effect cannot be exerted against a large impact force.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an energy-absorbing steering device that can reduce the shock to a driver at the initial stage of a collision and can exhibit a sufficient energy-absorbing effect even against large impact forces.

[Means to solve the problem]

In order to achieve the above object, the present invention includes an intermediate tube inserted into the gap between the outer tube and the inner tube, and a first ball inserted into the gap between the intermediate tube and the outer tube and the gap between the intermediate tube and the inner tube, respectively. One ball has a lower shock absorption load than the other ball, and the end face of the intermediate tube is positioned at the time of shock absorption to the outer tube or inner tube in contact with the ball on the lower load side. It is characterized by providing a restricting stopper surface.

[Effect]

In other words, when an impact force is applied to the outer tube, first only the balls on the low load side are transferred and absorb energy, and then the intermediate tube hits the stopper surface and stops, after which only the balls on the high load side are transferred. Absorb energy. In this way, it has two levels of shock absorption loads, so in the early stages of a collision or in a minor collision, the lower-load side ball cushions the driver's shock, while the higher-load side ball cushions the driver's shock in the event of a major collision. It has a great energy absorption effect.

〔Example〕

1 to 4 show a first embodiment of an energy absorbing steering device according to the present invention.

In the figure, a steering wheel 2 is fixed to the upper end of a steering shaft 1, and a steering shaft 1 is rotatably inserted and held within a cylindrical steering column 3. The steering column 3 is composed of an outer tube 4 and an inner tube 5 that can be freely inserted into and removed from each other. The tube 5 is fixed to the vehicle body.

Note that the steering shaft l is also supported so as to be movable in the axial direction.

As shown in FIG. 2, an intermediate tube 6 is fitted into the gap between the outer tube 4 and the inner tube 5, and a plurality of first balls 7 are inserted into the gap between the intermediate tube 6 and the outer tube 4. A plurality of second balls 8 are press-fitted into the gaps between the intermediate tube 6 and the inner tube 5, respectively. Note that 9.10 is a holding cylinder that holds the first ball 7 and the second ball 8 in a removable manner. The first ball 7 and the second ball 8 are made of balls with the same diameter, and the difference between the diameter of the first ball 7 and the gap between the tubes 4 and 6 is the difference between the diameter of the second ball B and the gap between the tubes 56. The difference is set to be slightly larger than the difference between the two.

In other words, the depth of penetration of the second ball 8 on the inside into the tubes 5, 6 is smaller than the depth of penetration of the first ball 7 on the outside into the tube 4.6, so the impact absorption load of the second ball 8 on the inside is absorbed by the outside. is smaller than that of the first ball 7. A stopper surface 5a is formed slightly below the insertion part of the inner tube 5 and the outer tube 4, with a constant distance δ from the lower end surface of the intermediate tube 6.
is capable of regulating the position of the lower end surface of the intermediate tube 6 during shock absorption.

Next, the operation of the steering device having the above configuration will be explained.

When a vehicle causes a collision and the driver collides with the steering wheel 2, the outer tube 4 moves in the axial direction (in the direction of the arrow in FIG. 2) relative to the inner tube 5.

At this time, since the shock absorption load of the inner second ball 8 is smaller than that of the outer first ball 7, the inner second ball 8
The chisel moves with a striation against the tube 5.6 and absorbs the impact energy. At this time, the second ball 8
Since the impact absorption load is small, the shock to the driver can be reduced. Eventually, as shown in FIG. 3, the lower end surface of the intermediate tube comes into contact with the stopper surface 5a, and the movement of the intermediate tube 6 is prevented.

After the intermediate tube 6 contacts the stopper surface 5a, the second
The ball 8 does not move, and only the first ball 7 on the outside moves while leaving a striation on the tube 4.6, as shown in FIG. 4, and absorbs the impact energy.

At this time, since the impact absorption load of the first ball 7 is larger than that of the second ball 8, even large impact energy can be effectively absorbed.

As is clear from FIG. 1, which shows the operating characteristics of the steering device, at the initial stage of the collision, the second ball 8 on the low load side is shown in FIG.
Since only the shock absorbs the impact energy, the shock to the driver can be reduced. After the intermediate tube 6 comes into contact with the stopper surface 5a during the stroke S1 of the outer tube 4, a large impact energy can be absorbed by the first ball 7 on the high load side. As described above, since the vehicle has two stages of shock absorption characteristics, it can alleviate the burden on the driver in the early stages of a collision or in a minor collision, and can exert a sufficient energy absorption effect in the case of a major collision.

FIG. 6 shows a second embodiment of the present invention, in which the same parts as in the first embodiment are given the same reference numerals and their explanations will be omitted. In this embodiment, the first ball 7 on the outside is on the low load side and the second ball 8 on the inside is on the high load side, and a stopper surface 4a is provided on the inner surface of the outer tube 4 with a constant distance δ from the intermediate tube 6. be. In this case, at the initial stage of the collision, only the first ball 7 on the low load side moves while leaving a streak, and after the intermediate tube 6 contacts the stopper surface 4a, the second ball 7 on the high load side moves.
The chisel moves while leaving streaks. Therefore, its shock absorption characteristics are similar to those shown in FIG.

Note that in the above embodiment, the first. In order to make the shock absorption load of the second ball different, the depth of the ball's penetration into the tube is set to be different, but this is not limitative. For example, the hardness of the tube surface in contact with the ball may be configured to be different. Good too.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, two layers of balls having different shock absorption loads are arranged in the gap between the outer tube and the inner tube, so that two levels of shock absorption characteristics can be obtained. Therefore, in the early stages of a collision or in the case of a minor collision, the shock to the driver can be alleviated by the lower-load side balls, and in the case of a larger collision, a sufficient energy absorption effect can be exerted by the higher-load side balls.

[Brief explanation of the drawing]

FIG. 1 is an overall view of the first embodiment of the energy absorbing steering device according to the present invention, FIG. 2 is a cross-sectional view of FIG. Fig. 5 is a diagram of its operating characteristics, Part 6 is a sectional view of the second embodiment, and Fig. 7 is a diagram of operating characteristics of the conventional example. 3... Steering column, 4... Outer tube, 5...・Inner tube, 4a, 5a... Stopper surface, 6... Intermediate tube, 7... First ball, 8
...Second ball. Patent applicant Daihatsu Motor Co., Ltd.

Claims (1)

[Claims] A steering column tube that rotatably holds a steering shaft is composed of an outer tube and an inner tube that can be freely inserted into and removed from each other, and a ball press-fitted into the gap between both tubes leaves streaks on the tube surface. In an energy-absorbing steering device that absorbs impact energy by moving while moving, an intermediate tube is inserted into the gap between the outer tube and the inner tube, and the gap between the intermediate tube and the outer tube and the gap between the intermediate tube and the inner tube are A first ball and a second ball are press-fitted into the outer tube and the second ball, respectively, so that one ball has a lower shock absorption load than the other ball, and the outer tube or inner tube in contact with the ball on the lower load side has a lower impact absorption load when absorbing shock. An energy absorbing steering device characterized in that a stopper surface is provided for positionally regulating the end surface of an intermediate tube.