JPH0649458B2 - Energy absorption type steering device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in an energy absorption type steering device. Here, the energy absorption type steering device absorbs the impact energy when the vehicle collides with another vehicle (primary collision) and the impact energy when the driver collides with the steering wheel (secondary collision) due to its reaction. Then, the driver's safety is ensured.

[Prior art and its drawbacks]

As an energy absorption type steering device that has been conventionally used, a steel ball (ball) is fitted into a small gap of a divided column, and when the column collapses, the ball plastically deforms the column to absorb the energy of collision. Type (hereinafter referred to as "ball type") and type that absorbs the energy of collision by pressing the bracket with a U-shaped slide plate or plastically deforming the curved (curling) plate (hereinafter referred to as "bracket type") Etc. are known.

As a conventional example of the ball type, Japanese Patent Publication No. Sho 46-3552
Those disclosed in Japanese Patent No. 7 and U.S. Pat. No. 3,788,148 are known. The former attempts to absorb the energy of collision entirely at the ball fitting portion between the inner and outer cylinders, and the pressure input is constant, and is generally about 200 to 400 kg. This has the drawback that the load generated when the column starts moving becomes high in the case of a secondary collision due to the effect of a primary collision. In the latter case, in order to suppress the load when the column starts moving and increase the load after moving by a predetermined amount, a plurality of parallel grooves are formed in a part of the inner cylinder in the axial direction in advance, and the ball after the predetermined amount of collapse is formed. Is plastically deformed in the portion following the end of the groove to absorb the shock while increasing the load. However, it is not easy to improve the accuracy of the width and depth of the groove and the parallelism between the grooves in addition to the time and labor required for processing the groove itself. If the processing accuracy is poor, the amount of plastic deformation of the inner cylinder due to the balls varies, and the energy absorption characteristics become uncertain and unstable.

On the other hand, as a conventional example of the bracket type, Japanese Patent Publication No. 59-46828 and Japanese Unexamined Patent Publication No. 56-2265.
What is disclosed in Japanese Patent Publication No. However, the steering column as a whole is integrated, and the lower end of the steering column is supported by a sliding guide so that the column does not rattle. No effect.

SUMMARY OF THE INVENTION The present invention provides an energy-absorption type steering device that solves the deficiency in the above-mentioned conventional example, that is, impact energy is reliably and stably absorbed, and can be easily achieved without complicating the overall structure of the steering device. It was made for the purpose of providing.

[Means and actions for solving problems]

In order to achieve the above object, in the present invention, the steering column is divided into an upper steering column and a lower steering column, and the upper steering column is attached to a part of the vehicle body via energy absorbing means (for example, a curling plate), The lower end of the upper steering column is guided and supported by a means which does not cause rattling in the radial direction without generating a large frictional resistance.

The guide support of the upper steering column, however, is such that the upper steering column and the lower steering column are fitted to each other at predetermined positions via balls, and then both columns are relatively moved by the collapse stroke in the direction in which the fitting length increases. By moving it, axial striations are formed on the inner peripheral surface or the outer peripheral surface of both columns. After that, both columns are relatively moved in the direction opposite to the above direction (direction in which the fitting length becomes shorter) by the collapse stroke to form an axial groove for the collapse stroke in front of the ball, and the predetermined set state is set. And That is, both columns are fitted via balls by a so-called "actual product matching" method to provide a guiding means for the upper steering column.

When a vehicle collides, the upper steering column moves smoothly, and the energy absorbing means absorbs the energy of the collision.

〔Example〕

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, an upper end portion of the lower steering column 10 and a lower end portion of the upper steering column 20 are telescopically fitted, and a steering shaft 30 penetrates the hollow portions of both. The lower end of the column 10 is fixed to a part 34 of the vehicle body by a support member 32,
The column 10 is immovable in the axial direction. A column bracket 36 is fixed to the outer side of the column 20, and a stepped flange portion 38 is formed on a part of the outer peripheral surface thereof. A curling plate 45 for absorbing energy is arranged between the flange portion 38 and the part 34 of the vehicle body. The plate 45 has a mounting portion 46 having substantially the same width as shown in FIGS. 1 and 2 and a width. Plastically deformed part (collapse part)
48 and has a U-shaped cross section as shown in FIG. The mounting portion 46 is fixed to the part 34 of the vehicle body with a screw 52 via a coating plate 50 having a U-shaped cross section and having a Teflon coating on the inner surface, and the deforming portion 48 is fixed to the flange portion 38.

Next, details of a portion where the lower steering column 10 and the upper steering column 20 are telescopically fitted will be described with reference to FIGS. 3 and 4. On the outer peripheral surface of the column 10, a suitable number (six in this case) of grooves 14 extending in the axial direction over a predetermined length from the end are continuously formed in parallel, while the inner peripheral surface of the column 20 is formed. Also, six grooves 24 are formed continuously in the axial direction and parallel to each other with a predetermined length from the end. Two balls 40 and 42, respectively, are interposed between the opposite grooves 14 and 24 of each pair, and the balls are axially and circularly divided by a cage 44 inserted between the columns 10 and 20. It is held so as to be located at a predetermined position in the circumferential direction.

The grooves 14 and 24 are located at the fifth position from the preset normal position.
As shown in the figure, after the columns 10 and 20 are relatively moved by a predetermined stroke S in the direction in which the length of the fitting portion increases (this stroke is equal to the collapse stroke as described later), the columns 10 and 20 are moved in the opposite direction. It is formed by relatively moving the same stroke.

Next, the function and effect of this embodiment will be described.

When a shock is applied to the vehicle body due to a collision or the like, the secondary collision causes the upper steering column 20 to move obliquely downward (in FIG. 1) with respect to the lower steering column 10. At this time, at the fitting portion of the columns 10 and 20, the balls 40 and 42 guide the moving direction of the column 20, and the balls 40 and 42 are press-fitted between the grooves 14 and 24. The column 20 is prevented from rattling.

If there is variation in the dimensions of the columns that are fitted together as in the conventional case, the load when press-fitting both columns varies from 150 to 400 kg, but once in the grooves 14 and 24 as in this embodiment. If it is re-pressed after forming, the load becomes 60 to 80 kg. That is, the load under pressure is reduced as a whole, the variation is small, and the load is stable. As a result, the energy absorption characteristics are determined only by the characteristics of the energy absorption bracket 45 described below, which facilitates the design. Also, since the load can be checked in the manufacturing process, better quality can be guaranteed. Also, since the two balls are axially separated, the guide characteristics are improved, and the grooves 14 and 24 are provided.
Since the column is formed by the collapse stroke, the column 20 is smoothly guided throughout the collapse of the bracket 45.

On the other hand, when the upper steering column 20 moves, the bracket 36 and the flange portion 38 move diagonally downward integrally with the upper steering column 20, and the collision energy is absorbed by the deformation of the energy absorbing curling plate 45 fixed to the flange portion 38 and the coating plate 50. Therefore, the driver is protected. Since the width of the deforming portion 48 of the curling plate is gradually increased toward the tip side, the energy can be effectively absorbed even when the impact is large. That is, as shown in FIG. 6, the resistance R of the bracket 45 to the movement of the column 20 is increased.
Is almost constant for a short collapse stroke S, but as the stroke increases, the resistance also increases and absorbs more energy.

The present invention is not limited to the above embodiment,
Modifications and improvements can be made as appropriate without departing from the spirit of the invention. For example, the energy absorbing means is not limited to the bracket 45, and the number of grooves and the like can be arbitrarily changed.

〔The invention's effect〕

As described above, according to the present invention, the lower end portion of the upper steering column and the upper end portion of the lower steering column forming the steering column are fitted through the balls by a so-called actual product matching method, and plastic deformation occurs. Since the groove is formed to guide and support the upper steering bracket, the upper steering column does not rattle during normal operation and the lower column holds the upper column during a collapse during a collision and moves smoothly. Energy is absorbed by the member that is plastically deformed by the heat. According to such guide means, the collision performance is determined only by the characteristics of the energy absorbing means, which facilitates the design of the steering device and has the effect of stabilizing the energy absorbing characteristics.

[Brief description of drawings]

FIG. 1 is a front view (partially broken) showing an embodiment of the present invention,
2 is a front view showing the energy absorbing bracket 45 in FIG. 1, FIG. 3 is an enlarged sectional view showing a fitting portion between the columns 10 and 20 in FIG. 1, and FIG. IV- in the figure
IV sectional view, FIG. 5 is an explanatory view showing the process of forming the grooves 14 and 24, and FIG. 6 is a graph showing the relationship between the collapse stroke S and the resistance R of the bracket 45. 10 ... Lower steering column 20 ... Upper steering column 34 ... Part of vehicle body 14, 24 ... Groove 40, 42 ... Ball 44 ... Energy absorbing member

Claims (3)

[Claims] 1. A steering shaft having a steering wheel attached to an upper end thereof is rotatably supported by a steering column, the steering column is divided into an upper steering column and a lower steering column, and one of the steering columns is provided with a ball through a ball. A direction in which the length of the fitting portion of both steering columns increases in order to fit the other steering column, after the columns are relatively moved by the collapse stroke, and then the length of the fitting portion decreases in the opposite direction. A column assembly in which axial grooves for the collapse stroke are formed in the upper steering column and the lower steering column by plastic deformation by relatively moving the upper stroke of the upper steering column and the vehicle body of the column assembly. Energy distributed between Yield means and; energy absorbing type steering device characterized by comprising a. 2. A plurality of pairs of axial grooves of the upper steering column and the lower steering column are circumferentially spaced from each other, and a plurality of axially spaced balls are provided between the facing grooves. Claims that are fitted together No. 1
The steering device according to the item. 3. The energy absorbing means according to claim 1, further comprising a curling member having a curved middle portion, one end attached to the upper steering column and the other end attached to a part of the vehicle body. Steering device.