JPH07329796A - Energy absorbing plate for shock absorbing type steering device - Google Patents

Abstract

PURPOSE:To lighten a shock acting on a driver's body striking against a steer ing wheel by reducing a peak load at the beginning of secondary collision. CONSTITUTION:Shock energy caused by secondary collision is absorbed by drawing the bending parts 28, 28 of energy absorbing plates 24, 24 whose rear ends are supported by a car body. Slots 29, 29 are formed in the bending parts to reduce the sectional areas of the bending parts 28, 28 for facilitating the plastic deformation of the bending parts 28, 28. Thus, a peak load at the beginning of the secondry collision does not increase in magnitude in spite of work hardening during forming the bending parts 28, 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The energy absorbing plate for a shock absorbing steering device according to the present invention absorbs impact energy and is plastically deformed in the event of a collision accident, so that the impact applied to the body of the driver bumping against the steering wheel is absorbed. ease.

[0002]

2. Description of the Related Art In a collision accident, a secondary collision occurs in which a driver's body collides with a steering wheel following a primary collision in which an automobile collides with another automobile. A driver protection device called a shock absorption type steering device is provided for the purpose of mitigating the shock applied to the driver's body during this secondary collision and preventing serious damage to the driver's body. Conventionally, various ideas have been considered. In addition, various members for absorbing impact energy in the case of secondary collision have been conventionally known. Among them, the energy absorbing plate has been conventionally generally used as a member that can obtain a relatively simple, small-sized and inexpensive shock absorbing steering device.

FIGS. 6 to 7 show a first example of a conventional shock absorbing type steering device incorporating such an energy absorbing plate, which is disclosed in Japanese Utility Model Publication No. 51-41700. Inside the steering column 1, a steering shaft 2 is provided.
It is supported only to rotate with respect to. A steering wheel (not shown) is fixed to the rear end of the steering shaft 2 (the end further to the right of FIG. 6). On the other hand, on the lower surface of the vehicle body 3, a support bracket 4
It is fixed by 5. The steering column 1
Are inserted inside the support bracket 4.
Further, the support bracket 4 does not move even in the case of a collision accident.

An energy absorbing plate 6 is mounted on the upper surface of the steering column 1. The energy absorbing plate 6 is made of a plastically deformable metal plate such as a mild steel plate, and its front and rear end edges (left and right end edges in FIG. 6) are fixed to the upper surface of the steering column 1 by welding. A bent portion 7 projecting upward in a chevron shape is formed in the front portion of the energy absorbing plate 6 toward the front of the intermediate portion (to the left of FIG. 6). Further, three horizontal shafts 8, 8 which are fixing members are bridged over the upper part of the support bracket 4, and rollers 9, 9 are rotatably supported on the horizontal shafts 8, 8, respectively. A gap exists between the outer peripheral surfaces of the adjacent rollers 9 and 9, and the bent portion 7 of the energy absorption plate 6 is located in this gap.

The shock absorbing steering system constructed as described above acts as follows in the event of a collision to alleviate the shock applied to the driver's body that hits the steering wheel. At the time of a secondary collision, the energy absorption plate 6 is forward with the steering column 1 (left side in FIG. 6).
Is displaced to. On the other hand, the rollers 9, 9 supported by the support bracket 4 via the horizontal shafts 8, 8 are not displaced. Therefore, the bent portion 7 of the energy absorbing plate 6 moves behind the energy absorbing plate 6 (to the right in FIG. 6) while being squeezed by the rollers 9, 9. At this time, the energy absorbing plate 6 is continuously plastically deformed in the length direction (the left-right direction in FIG. 6). Such plastic deformation of the energy absorbing plate 6 is performed by the impact energy applied to the steering column 1 by the secondary collision. Therefore, the energy absorbing plate 6
The impact energy is absorbed by the amount of plastic deformation of
The impact on the body of the driver bumping against the steering wheel is reduced.

Next, FIGS. 8 to 10 show a second example of a conventional shock absorbing type steering device incorporating an energy absorbing plate, which is disclosed in Japanese Utility Model Laid-Open No. 63-142256. A steering shaft 2a is rotatably supported inside the steering column 1a only with respect to the steering column 1a. The steering column 1a is formed by combining an upper column 10 and a lower column 11 in a telescope shape.
Therefore, the entire length of the steering column 1a is shortened when a strong compressive force is applied in the axial direction (left and right direction in FIG. 8). In the steering shaft 2a, a shaft-shaped upper shaft 12 and a tubular lower shaft 13 are connected by a spline engagement portion 14. The circular holes 15, 15 and the concave grooves 16, 16 provided in the spline engaging portion 14 are filled with synthetic resin 17, 17.
Therefore, when a strong compressive force is applied to the steering shaft 2a in the axial direction, the synthetic resin 17,
Shred 17 to reduce the overall length. A steering wheel (not shown) is fixed to the rear end portion (right end portion in FIG. 8) of the steering shaft 2a.

On the other hand, a support bracket 4a is fixed to the outer peripheral surface of the rear end portion (right end portion in FIG. 6) of the upper column 10 by welding or the like. This support bracket 4a made by press forming a steel plate or the like having sufficient rigidity
Has a pair of left and right mounting plate portions 18. Each mounting plate part 18
At the rear end (the right end in FIGS. 8 to 10) of the mounting plate portion 1
A notch 19 that opens at the rear edge of the No. 8 is formed.
A locking piece 20 is attached to the cutout 19 portion. Then, the locking piece 20 is fixed to the vehicle body 3a by the bolt 5 which is a fixing member. This locking piece 2
0 is made of synthetic resin, aluminum alloy, or the like, and is normally held in each of the cutouts 19. However, when a strong force is applied, the cutouts 0 are rearward (see FIG. 8). Exit to the right of 10).

A rear end of the energy absorbing plate 6a is locked to the lower end of the bolt 5. That is, the lower end of the bolt 5 is inserted into the elongated hole 21 formed at the rear end of the energy absorbing plate 6a to support the rear end of the energy absorbing plate 6a with respect to the vehicle body 3a. On the other hand, a pair of slits 22 and 22 are provided at the front part (left part of FIGS. 8 to 10) of each of the mounting plate parts 18, respectively.
It is formed at intervals. The portion 23 sandwiched between the slits 22 and 22 is curved in a direction in which the upper surface is convex. The energy absorbing plate 6a
A bent portion 7a similar to that in the case of the above-described first example is formed in the rearward portion of the intermediate portion (closer to the right in FIGS. 8 to 10). The intermediate portion of the bent portion 7a is set to the above-mentioned intermediate portion 23.
The upper and lower ends of the bent portion 7a are inserted into the pair of slits 22, 22.

The shock absorbing steering system constructed as described above acts as follows in the event of a collision to alleviate the shock applied to the driver's body that hits the steering wheel. In the case of a secondary collision, the support bracket 4a
Is displaced forward (to the left in FIGS. 8 to 10) together with the upper column 10. On the other hand, the bolt 5 and the locking piece 20 remain in the position where they are supported by the vehicle body 3a.
Therefore, the energy absorbing plate 6a whose rear end portion is locked to the bolt 5 is also supported in almost the same position without being displaced forward in the elongated hole 21 beyond the displaceable distance of the bolt 5. It

As described above, the support bracket 4a is displaced forward while the energy absorbing plate 6a is supported at the same position, and as a result, the bent portion 7 of the energy absorbing plate 6a is bent by the gap portion 23. In front of the energy absorbing plate 6a (see FIGS.
Move to the left of 10). At this time, the energy absorption plate 6a has a length direction (left and right direction in FIGS. 8 to 10).
It continuously undergoes plastic deformation over time. As a result, the impact energy applied to the upper column 10 is absorbed, and the impact applied to the body of the driver bumping the steering wheel is alleviated.

[0011]

However, the energy absorbing plate incorporated in the conventional shock absorbing type steering device configured and functioning as described above has the following points to be solved. That is, in any structure, the energy absorbing plates 6 and 6a are plastically deformed so as to squeeze the bent portions 7 and 7a formed in advance in the case of the secondary collision.
Therefore, in order to surely absorb the impact energy,
It is necessary that the bent portions 7 and 7a are easily plastically deformed.

On the other hand, when the bent portions 7 and 7a are formed on a metal plate such as a mild steel plate by pressing or the like, the bent portions 7 and 7a are hardened by work hardening and are less likely to be plastically deformed. As a result, the effect of absorbing the impact energy at the time of the secondary collision is reduced accordingly. It is preferable that the impact force applied to the driver's body during a secondary collision is as low as possible, and improvement is desired. The energy absorbing plate for a shock absorbing steering device of the present invention was invented in view of such circumstances.

[0013]

An energy absorbing plate for a shock absorbing type steering device according to the present invention supports a steering shaft rotatably inside and is supported on a steering column which is displaced forward by the impact of a collision accident and a vehicle body. A fixed member that is not displaced regardless of the impact of a collision accident, and has a bent portion in the middle part that is made of a plastically deformable metal plate, and is engaged with the fixed member and the steering column. , An energy-absorbing steering device having an energy-absorbing plate that absorbs impact energy resulting from a collision accident. In particular, in the energy absorption plate for a shock absorbing steering device of the present invention, the cross-sectional area of the bent portion forming portion is smaller than the cross-sectional area of the non-forming portion.

[0014]

The energy absorbing plate for a shock absorbing steering device of the present invention configured as described above absorbs impact energy by squeezing the bent portion in the longitudinal direction during a secondary collision, It reduces the impact on the driver's body that hits the steering wheel. In particular,
In the case of the energy absorption plate for a shock absorbing steering device of the present invention, since the cross-sectional area of the bent portion forming portion is smaller than the cross-sectional area of the non-forming portion, the bent portion forming portion is easily plastically deformed. . Therefore, even if the bent portion forming portion becomes hard due to work hardening, the bent portion does not become easily plastically deformed, and the impact energy absorbing effect is enhanced.

[0015]

1 to 3 show a first embodiment of the present invention. A steering shaft 2a is rotatably supported inside the steering column 1a only with respect to the steering column 1a. A support bracket 4b is fixed to the outer peripheral surface of the rear end of the steering column 1a by welding or the like. This support bracket 4b made by press-forming a steel plate or the like having sufficient rigidity
Has a pair of left and right mounting plate portions 18, 18. Notches 19 and 19 that open to the rear end edges of the mounting plate portions 18 and 18 are provided at the rear end portions of the mounting plate portions 18 and 18 (right end portions in FIG. 1).
Are formed. Then, the locking pieces 20, 20 are attached to the inner portions of the notches 19, 19. At the time of mounting on the vehicle, the locking pieces 20, 20 are fixed to the vehicle body by bolts (not shown) which are fixing members. The locking pieces 20 and 20 are made of aluminum alloy or the like, and normally, the small holes 35 formed in the locking pieces 20 and 20,
35 and synthetic resin 26, 26 formed in each of the mounting plate portions 18, 18 and laid over the small holes 35, 35 and another small hole aligned with the small holes 35, 35. Is held. However, when a strong impact force due to a secondary collision acts, the synthetic resin 26, 26 loses its supporting force due to shearing, and is rearward from each of the notches 19, 19 (right in FIGS. 1-2). One).

Further, at the time of mounting on a vehicle, the rear ends of the energy absorbing plates 24, 24 of the present invention are locked to the lower ends of the bolts through the locking pieces 20. That is, the lower end portion of the bolt is inserted into the circular hole 25 formed at the rear end portion (the right end portion in FIGS. 1 and 2) of the energy absorbing plates 24, 24, and the rear end portions of the energy absorbing plates 24, 24 are inserted. To the vehicle body. This energy absorption plate 24, 2
Bent portions 28, 28 protruding downward in a mountain shape are formed in the rear portion of the intermediate portion 4 (to the right of FIGS. 1 and 2). In particular, in the case of the energy absorbing plates 24, 24 of the present invention, the long hole 2 that is long in the front-rear direction (the left-right direction in FIGS. 1 and 2) is formed in the widthwise central portion of the bent portions 28, 28 forming portion.
9 and 29 are formed. And these long holes 29, 29
The cross-section area (thickness dimension × width dimension of the filled portion) of each of the bent portions 28, 28 is calculated by
It is made smaller than the cross-sectional area (thickness dimension × width dimension) of the portion in which is not formed (non-formed portion).

On the other hand, through holes 27 and 27 are formed in the front portions (left portions in FIGS. 1 and 2) of the mounting plate portions 18 and 18, respectively. At a part of each of the mounting plate portions 18, 18, the front edge (the left side edge of FIGS. 1 and 2) of each of the through holes 27, 27 has a cross section of a quarter arc, and the tip edge thereof is The front guide plate portions 30, 30 are formed to project downward. Further, at the rear edge portion (right side edge in FIGS. 1 and 2) of each of the through holes 27, 27, a rear guide plate portion 31 having a substantially inverted U-shaped cross section and having its tip edge projected downward, 31 is formed. Further, the left and right side edges (upper and lower side edges in FIG. 1) of each of the through holes 27, 27 have a pair of restraining plate portions 3, respectively.
2, 32 and the receiving plate portions 33, 33 are formed.

These restraining plate portions 32, 32 and the receiving plate portion 33,
The reference numeral 33 refers to the pressing plate portions 32, 32 and the through holes 27, 27.
They are provided adjacent to each other. Further, the restraining plate portions 32, 32 project upward in a mountain shape, and the lower surfaces thereof have an arcuate concave surface, and the receiving plate portions 33, 33 have an upper surface having an arcuate concave surface. Then, between the lower surfaces of the restraining plate portions 32, 32 and the upper surfaces of the receiving plate portions 33, 33, the ironing pins 34,
It supports both ends of 34. Therefore, the ironing pins 34, 34 are supported in a state of traversing the central portion of the through holes 27, 27 in the front-rear direction across the width direction. In this state, the lower surfaces of the ironing pins 34, 34 are
It exists below the upper surface of each of the mounting plate portions 18, 18. In the illustrated embodiment, as the ironing pins 34, 34, spring pins having a hollow cylindrical shape and having elasticity in a direction of expanding the outer diameter are used.

The bent portions 28, 28 of the energy absorbing plates 24, 24 constructed as described above are passed under the ironing pins 34, 34, and the ironing pins 3 are formed.
They are arranged so as to surround 4, 34.

The shock absorbing type steering device having the energy absorbing plates 24, 24 of the present invention, which is constructed as described above, acts as follows in the event of a collision and the driver who hits the steering wheel. Alleviate the impact on your body. In the case of a secondary collision, the supporting bracket 4b
Is displaced forward (to the left in FIGS. 1 and 2) together with the steering column 1a. On the other hand, the bolt and the locking piece 20 remain as they are in the position supported by the vehicle body. Therefore, the energy absorbing plate 24 whose rear end is locked to the bolt is also supported in the same position without being displaced forward.

As described above, the support bracket 4b is displaced forward while the energy absorbing plate 24 is supported at the same position, and as a result, the bent portions 28, 28 of the energy absorbing plates 24, 24 are bent toward the front side. The front side of the energy absorbing plate 24 (the left side of FIGS. 1 and 2) is squeezed between the guide plate portions 30, 30 and the rear guide plate portions 31, 31 and the lower surfaces of the ironing pins 34, 34. Move to. At this time, the energy absorbing plate 24 is continuously plastically deformed in the length direction (the left-right direction of FIGS. 1 and 2). As a result, the impact energy applied to the steering column 1a is absorbed, and the impact applied to the body of the driver bumping the steering wheel is alleviated.

Particularly, in the case of the energy absorbing plates 24, 24 for shock absorbing type steering according to the present invention, the bent portions 28, 2 are formed by the length of the elongated holes 29, 29.
8. The cross-sectional area of the formed portion is smaller than that of the non-formed portion. Therefore, the portions where the bent portions 28, 28 are formed are likely to be plastically deformed, and even if the portions where the bent portions 28, 28 are formed become hard due to work hardening, the bent portions 28, 28 are particularly plastic. It will not be easily deformed. As a result, the effect of absorbing impact energy during the secondary collision is enhanced. In addition, since the cross-sectional area other than the portion where the bent portions 28, 28 are formed (non-formed portion) is sufficiently secured, the front guide plate portions 30, 30 and the rear guide plate portions 31, 31 are subjected to a secondary collision. The force required for plastically deforming the energy absorbing plates 24, 24 by squeezing between the lower surfaces of the ironing pins 34, 34 does not become too small. Therefore, each of these energy absorbing plates 24, 24
As a result, the amount of energy that can be absorbed can be sufficiently secured.

For example, the present inventor has shown a pair of energy absorbing plates 24, 24 having the long holes 29, 29 formed therein and an energy absorbing plate having no such long holes 29, 29 shown in FIG. 2 is incorporated into an impact absorption type steering column device, the impact load applied in the axial direction of the steering column 1a when the steering column 1a is displaced forward is measured, and the results shown in FIG. 3 are obtained. Was obtained. The material of the energy absorbing plate was cold rolled steel strip SPCC (JIS G 3141), and the width dimension was 14 mm and the thickness dimension was 1.2 mm. Also, the long holes 29, 2
The width dimension of 9 was 7 mm.

Of the two curves shown in FIG. 3 showing the experimental results, the solid line α represents the change in load when no long hole is formed.
The broken line β indicates the load change when the long holes 29, 29 are formed,
Each represents. As is clear from the description of FIG. 3, when the energy absorbing plate of the present invention is used, the peak load generated at the initial stage of the secondary collision while securing a sufficient energy absorbing capacity (200 kgf in the case of the experimental example). Can be suppressed. Therefore, it is possible to reduce the impact applied to the body of the driver that hits the steering wheel.

Next, FIGS. 4 to 5 show a second embodiment of the present invention. In the case of the first embodiment described above, the elongated hole 29 is formed in the widthwise central portion of the bent portion 28 of the energy absorbing plate 24.
By forming (FIG. 1), the cross-sectional area of the bent portion 28 is made small, whereas in the case of the present embodiment, the width dimension of the bent portion 28 is made small so that the bent portion 28 is formed. The cross-sectional area of is reduced. The function and effect in the state of being incorporated in the shock absorbing steering device are the same as those in the above-described first embodiment.

The gist of the present invention resides in the energy absorbing plates 24, 24a.
It is not in the structure of the shock absorbing type steering device in which 4, 24a are incorporated. Therefore, the present invention can also be applied to the energy absorbing plates 6 and 6a incorporated in the structure shown in FIGS. 6 to 7 or the structure shown in FIGS.

[0027]

The energy absorption plate for a shock absorption type steering column of the present invention is constructed and operated as described above, and while ensuring a sufficient energy absorption capacity, the peak load generated in the initial stage of the secondary collision is prevented. Can be suppressed. Therefore, it is possible to alleviate the impact applied to the driver's body that hits the steering wheel, and more reliably protect the driver's life.

[Brief description of drawings]

FIG. 1 is a plan view of a main part of an impact absorption type steering device incorporating an energy absorption plate, showing a first embodiment of the present invention.

FIG. 2 is a side view showing a part of the same.

FIG. 3 is a diagram showing the results of an experiment conducted to confirm the effect of the present invention.

FIG. 4 is a partial plan view of an energy absorption plate showing a second embodiment of the present invention.

FIG. 5 is a partial side view of the same.

FIG. 6 is a partial vertical sectional side view showing a first example of a conventional structure.

7 is a cross-sectional view taken along the line AA of FIG.

FIG. 8 is a partial vertical sectional side view showing a second example of the conventional structure.

FIG. 9 is a partial plan view of the same.

FIG. 10 is a perspective view seen from the direction of arrow B in FIG.

[Explanation of symbols]

 1, 1a Steering column 2, 2a Steering shaft 3, 3a Car body 4, 4a, 4b Support bracket 5 Bolt 6, 6a Energy absorption plate 7, 7a Bending portion 8 Horizontal shaft 9 Roller 10 Upper column 11 Lower column 12 Upper shaft 13 Lower Shaft 14 Spline engagement portion 15 Circular hole 16 Recessed groove 17 Synthetic resin 18 Mounting plate portion 19 Notch 20 Engaging piece 21 Long hole 22 Slit 23 Intersection 24, 24a Energy absorbing plate 25 Circular hole 26 Synthetic resin 27 Through hole 28 Bent part 29 Long hole 30 Front side guide plate part 31 Rear side guide plate part 32 Suppression plate part 33 Receiving plate part 34 Ironing pin 35 Small hole

Claims (1)

[Claims] 1. A steering column that rotatably supports a steering shaft inside and is displaced forward by the impact of a collision accident; and a fixing member that is supported by a vehicle body and does not displace regardless of the impact of the collision accident. Impact including an energy absorbing plate that is made of a plastically deformable metal plate and has a bent portion in an intermediate portion, engages with the fixing member and the steering column, and absorbs impact energy associated with a collision accident An energy absorption plate incorporated in an absorption type steering device, wherein the cross-sectional area of the bent portion forming portion is smaller than the cross-sectional area of the non-forming portion.