JP2000203433A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform rotation operation of a steering column when the mounting state of the steering column is released and to relax an impact during secondary collision through advance operation of a steering wheel based on rotation operation of a steering column. SOLUTION: This device comprises a lower bush 33 fitted in a position situated externally of the lower part of a steering column 1 and a lower bracket 34 to mount the lower part of the steering column 1 to a fixing member 2 by surrounding the outer periphery of the lower bush 33. A force higher than a specified value to relatively move downward the steering column 1 to a fixing member 2 is generated, a lower bush 33 is separated away from the lower bracket 34. In this case, the lower bush 33 is formed that the thickness in a radial direction of the rear part 33a, positioned in the rear of a vehicle, of the steering column 1 is higher than that of the front part 33b, positioned in front of a vehicle, of the steering column 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering system, and more particularly, to a shock absorbing function when a driver collides with a steering wheel (secondary collision) following a forward collision (primary collision) of an automobile. The present invention relates to a steering device suitable for

[0002]

2. Description of the Related Art An example of a conventional steering device is shown in FIG. In this steering device, a substantially cylindrical lower bush 90 is externally fitted to a lower portion of a steering column 9 that supports a steering shaft 95, and a fixing member 9 is provided.
This is a means for surrounding and holding the outer periphery of the lower bush 90 by the lower bracket 92 attached to the first bracket 1. The lower bush 90 is press-fitted between the steering column 9 and the cylindrical portion of the lower bracket 92, and an engagement portion 90 provided at a lower end of the lower bush 90 is provided.
a is engaged with the lower end surface of the steering column 9.

In a steering device having such a structure,
When a force F2 of a certain value or more for lowering the steering column 9 relative to the fixed member 91 is generated, the lower bush 90 can be detached from the lower bracket 92 as shown in FIG. 9 can be lowered relative to the fixing member 91. Of course, this is based on the premise that when the upper part of the steering column 9 is fixedly attached to, for example, the fixing member 91, the upper attaching part has a structure that allows the above-described lowering operation of the steering column 9. I have. In such a steering device, for example, the structure in which the force F2 is generated when the vehicle causes a front collision can pull the steering column 9 downward at the time of the front collision of the vehicle. Therefore, if the steering shaft 95 and the steering wheel 96 are also lowered along with the retracting operation of the steering column 9, the impact when the driver collides with the steering wheel 96 in the subsequent secondary collision is reduced. It becomes possible.

[0004]

However, in the above-mentioned conventional steering apparatus, only the operation of pulling the steering column 9 downward with respect to the fixed member 91 can be obtained, and the impact at the time of the secondary collision is reduced. From a viewpoint, there is still room for improvement. More specifically,
The applicant of the present application not only detaches the steering column from the fixed member at the time of the primary collision but also rotatably supports the steering column after the detachment, as means for enhancing the impact relaxation effect at the time of the secondary collision. The idea was to move the steering wheel to the front of the vehicle by rotating the steering column (Japanese Patent Application No. 10-360).
No. 402). However, in the above-mentioned conventional structure, FIG.
As shown in FIG.
Even after the steering column 9 is detached from the steering column 9, the steering column 9 is still surrounded by the lower bracket 92, and the gap Sa between the outer periphery of the steering column 9 and the inner surface of the lower bracket 92 is very small. Therefore, conventionally, the steering column 9 is fixed to the fixed member 91.
Even if the steering column 9 is rotated in the direction in which the steering wheel 96 moves forward (in the direction of the arrow N5) after the vehicle is disengaged from the vehicle, the lower bracket 92 becomes an obstacle, and such an operation can be actually performed. Did not.

The present invention has been conceived in view of such circumstances, and enables the rotation of the steering column when the mounted state of the steering column is released. It is an object of the present invention to provide a steering device capable of reducing an impact at the time of a secondary collision by a forward movement of a steering wheel based on the steering operation.

[0006]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

A steering device provided by the present invention comprises a lower bush externally fitted to a lower portion of a steering column, and a lower bracket for surrounding the outer periphery of the lower bush to attach the lower portion of the steering column to a fixed member. And wherein when a force equal to or more than a predetermined value for moving the steering column relative to the fixed member downward is generated, the lower bush separates from the lower bracket. In the steering device, the lower bush has a greater thickness in a radial direction at a rear portion of the steering column located at the rear of the vehicle than at a front portion of the steering column located at the front of the vehicle. .

[0008] In the present invention, the radial thickness (wall thickness) of the lower bush fitted externally to the lower portion of the steering column is not uniform, and the rear portion of the steering column located at the rear of the vehicle is located at the front of the vehicle. It is thicker than the front. For this reason, in the fixed mounting state of the steering column in which the outer periphery of the lower bush is surrounded by the lower bracket, the rear surface of the steering column that faces the rear of the steering column sandwiching this rear portion is increased by the thickness of the rear portion of the lower bush. The distance between the lower bracket and the inner surface of the lower bracket increases, and when the lower bush separates from the lower bracket, a large gap is formed between the rear surface of the steering column and the inner surface of the lower bracket. It is possible to do. If a large gap is formed in this manner, the lower portion of the steering column can be moved rearward in the gap within the gap. Therefore,
When the fixed installation state of the lower part of the steering column is released, if the upper part of the steering column is supported by an appropriate means that allows the rotation operation of the steering column, for example, the steering column is centered on the supporting part. The upper end can be rotated in a direction in which the upper end moves forward of the vehicle.

As described above, according to the present invention, when the fixed mounting state of the lower portion of the steering column is released,
This steering column can be rotated in the direction in which the upper end moves forward of the vehicle. Therefore, it is suitable to reduce the impact at the time of the secondary collision by moving the steering wheel forward of the vehicle based on the rotation operation of the steering column. In particular, in the present invention, since the lower bracket can rotate the steering column while surrounding the lower portion of the steering column, the lower bracket can guide the movement of the steering column during the rotation operation of the steering column. The forward movement of the steering wheel can be ensured by preventing the column from falling down in an inappropriate direction such as the vehicle width direction.
Further, in the present invention, since the front portion of the lower bush is smaller in thickness than the rear portion, the entire lower bush can be prevented from becoming extremely large in size, and the lower bracket surrounding the lower bush can be enlarged. Can be avoided as much as possible. Further, according to the present invention, the number of parts is not increased as compared with the conventional case, and the manufacture thereof is easy.

[0010] Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a side sectional view of an essential part showing an example of a steering device to which the present invention is applied. FIG. 2 is an enlarged view of a main part of FIG. FIG. 3 is an exploded perspective view of a main part of the steering device shown in FIG. FIG. 4 is an enlarged view of a main part showing an operation state of the mechanism shown in FIG. FIG.
FIG. 5 is a side sectional view of a relevant part showing the operation of the steering device shown in FIG. In the drawings after FIG. 1, an arrow Fr indicates the front of the vehicle, and an arrow Up indicates an upper part in the vehicle height direction.

In FIG. 1, a steering device A of this embodiment is incorporated in a so-called cab-over type automobile, and includes a steering column 1, a bracket 2, and upper and lower mounting portions for mounting the steering column 1 to the bracket 2. 3a and 3b. The lower mounting portion 3b includes a lower bush 33 and a lower bracket 34, and the steering device A of the present embodiment has the greatest feature in the structure of this portion.

The steering column 1 is a cylindrical member for rotatably supporting a steering shaft 5 having a steering wheel 4 mounted on an upper end thereof around an axis thereof. The upper column and the lower column are combined. The steering column 1 is provided in a state where relative movement in the longitudinal direction with respect to the steering shaft 5 is impossible. The lower portion of the steering shaft 5 is connected to a gear box 51 fixedly attached to a frame (not shown) at the lower front floor of the vehicle via a plurality of universal joints 50 and the like. This gear box 51
Is provided at a position closer to the rear of the vehicle than the bracket 2, so that when a front collision of the vehicle occurs, the vehicle does not move backward to the rear of the vehicle prior to the bracket 2.

The bracket 2 is formed, for example, by pressing a metal plate, and corresponds to an example of a fixing member according to the present invention. However, the bracket 2 serves not only as a support for the steering column 1 but also as a so-called pedal bracket, on which the brake pedal 70 and other pedals are mounted. Although not shown, a brake booster connected to the arm of the brake pedal 70 is also attached to the bracket 2. The lower end of the bracket 2 is fixedly attached to a fixed bracket 72 on a floor panel 71 using bolts 73 or the like, and stands upright above the fixed bracket 72. However, the bracket 2 is provided with an inclined portion 20 that extends obliquely upward from the middle or upper portion in the height direction toward the rear of the vehicle. The inclined portion 20 is a portion for attaching the steering column 1, and an upper end portion of the inclined portion 20 is connected to an apparel reinforcement 75 via a stay 74. The apparel reinforcement 75 is a member having a large rigidity that forms a lower edge portion 77 of the front window portion 76,
In general automobiles, it corresponds to a cowl or a member for reinforcing the cowl.

The bracket 2 is also connected to a cross member 76 via a stay 78, so that the fixing strength of the bracket 2 is increased. However, the stay 78 is formed so as to bend relatively easily so that the stay 78 itself does not exert a large force for pressing the bracket 2 rearward when the cross member 76 retreats during a forward collision of the vehicle. ing. The cross member 76 is a member that is located forward of the bracket 2 and extends in the vehicle width direction, and further forward of the cross member 76 is a front panel 79 that is the foremost part of the vehicle.

2 and 3, the upper mounting portion 3
a, after the upper bracket 12 welded to the upper part of the steering column 1 is sandwiched by the clamp pieces 30 having a substantially U-shaped cross section, these bolt insertion holes 12a, 3
0a and a nut 31 screwed into the bolt 31
a, the upper bracket 12 is fastened to the seat portion 20a of the inclined portion 20. The holder 32 surrounding the upper outer peripheral surface of the steering column 1 is also assembled using the bolt 31.

The clamp piece 30 includes a bolt 31 and a nut 3
The upper bracket 12 is clamped from both sides indicated by arrows N1 and N1 by the tightening force with the steering column 1a, and the steering column 1 is fixed by the clamping force. Bolt insertion hole 1 of upper bracket 12
2a is a cutout hole whose upper end is open.
Therefore, in this mounting portion 3a, as shown in FIG.
A force F1 is generated to move the inclined portion 20 of the bracket 2 obliquely upward relative to the steering column 1,
When the force F1 becomes equal to or more than a certain value, the upper bracket 12 separates from the clamp piece 30 downward,
The fixed mounting state of the upper portion of the steering column 1 with respect to the bracket 2 is released. However, since the holder 32 of the upper attachment portion 3a remains attached to the inclined portion 20 of the bracket 2 by the bolt 31, the holder 32 supports the upper portion of the steering column 1. In the structure shown in FIG.
Since the upper portion of the steering column 1 is fixed to the bracket 2 even when the steering column 1 is not provided, the holder 32 has a function for fixing the steering column 1 to the bracket 2 in a normal state. You don't have to.

The lower mounting portion 3b has a structure in which a lower bush 33 is externally fitted to a lower portion of the steering column 1 and the lower bush 33 is fitted into a tubular portion 34a of a lower bracket 34. Lower bush 3
Reference numeral 3 is made of, for example, a synthetic resin, and has an elliptical outer shape in a front view, as shown well in FIG. 3, and its hole 33c is eccentric from the center of the entire bush. For this reason, the thickness of each part in the radial direction (direction orthogonal to the direction in which the axis extends) around the hole 33 c of the lower bush 33 is different. Specifically, as shown in FIG.
Is fitted to the steering column 1,
Rear part 3 located behind the steering column 1 in the vehicle
The thickness ta of 3a is the largest dimension compared to the thickness of the other parts, and the thickness tb of the front portion 33b located in front of the steering column 1 in the vehicle is considerably smaller than the thickness ta. I have. An engaging portion 33d that engages with the lower end end surface of the steering column 1 is provided on the periphery of the one end opening of the hole portion 33c of the lower bush 33.

As shown in FIG. 3, the lower bracket 34 has a bolt insertion hole 34c formed on the outer surface of the cylindrical portion 34a.
The fixing plate portion 34b is provided with a plate-shaped fixing plate portion 34b. The fixing plate portion 34b is fastened to the inclined portion 20 of the bracket 2 by using bolts 35 to fix and attach to the inclined portion 20. Have been. Cylindrical part 34a
Has a shape corresponding to the lower bush 33, and the lower bush 33 is formed with the cylindrical portion 34 a and the steering column 1.
Is press-fitted into the gap with the lower part. Therefore, in the lower mounting portion 3b, as shown in FIG. 4, when the above-mentioned force F1 of a certain value or more is generated, the lower bracket 3
The lower bush 33 is disengaged downward from the cylindrical portion 34a of No. 4 and the fixed state of the lower portion of the steering column 1 is released.

Next, the operation of the steering device A will be described.

First, a car causes a forward collision,
As shown in FIG. 5, when a very large load F is input to the front of the vehicle body from the front thereof, the front of the vehicle body crashes and, for example, the bracket 2 is pressed to the rear of the vehicle by the cross member 76. Since the upper and lower portions of the bracket 2 are firmly connected to predetermined portions of the vehicle body, the bracket 2 does not easily move backward to the rear of the vehicle. Occurs.
Since the inclined portion 20 has a form extending obliquely toward the rear of the vehicle, when a load input is received from the front, the inclined portion 20 is configured to rise upward in which the inclined portion 20 extends. A force F1 is generated, which is intended to be deformed. In this case, since the upper end of the inclined portion 20 is connected to the rigid reinforcement 75 via the stay 74, the inclined portion 20 rotates upward about the connection point between the stay 74 and the reinforcement 75. And the rearward movement of the vehicle can be minimized. On the other hand, the steering shaft 5 supported by the steering column 1 is connected to a gear box 51 whose lower end is fixed, and the force F1
Demonstrate resistance to As a result, when the force F1 becomes equal to or more than the predetermined value, the fixed state of the steering column 1 by the mounting portions 3a and 3b is released as shown in FIG.

However, the upper portion of the steering column 1 can be maintained in a state where the outer periphery thereof is surrounded by the holder 32, so that the entire steering column 1 does not fall on the floor panel 71. 32 can be supported. On the other hand, the lower part of the steering column 1
3 is detached from the lower bracket 34, a lower bush 3 is provided between the rear surface 1a of the lower portion of the steering column 1 and the inner surface 34a 'of the cylindrical portion 34a facing the lower surface 1a.
3, a gap S having a considerably large width equal to the thickness ta of the rear portion 33a is formed. Therefore, the rear surface 1a of the lower portion of the steering column 1 is
Arrow N in the range up to contact with the inner surface 34a '
Thus, there is room to move toward the rear of the vehicle, as shown in FIG.

For this reason, as shown in FIG. 5, the steering column 1 is rotatable in the direction of arrow N2 about a portion supported by the holder 32. If the holder 32 is formed of a flexible member or a relatively soft member that is easily deformed, the rotation of the steering column 1 can be made smooth. The inner surface of the tubular portion 34a of the lower bracket 34 serves to guide the lower portion of the steering column 1 to move rearward in the vehicle. Therefore, the rotation direction of the steering column 1 can be accurately defined in the direction of the arrow N2. Since the lower portion of the steering shaft 5 can be bent in various directions due to the presence of the universal joint 50, the steering shaft 5 can be prevented from hindering the rotation operation of the steering column 1. Therefore, even if a driver collides with the steering wheel 4 subsequent to the primary collision of the preceding vehicle, that is, even if a secondary collision occurs, the steering column 1 is rotated by turning the steering column 1 to the arrow N3 in that case. Can be moved forward of the vehicle, and the impact at the time of the secondary collision can be reduced. Further, the steering column 1 may rotate immediately due to its inertia immediately after the fixed state of the bracket 2 with the inclined portion 20 is released, and in this case, the steering wheel 4 may be rotated before the secondary collision occurs. Can be moved forward. Therefore, even in this case, it is possible to reduce the impact force at the time of the secondary collision by the distance that the steering wheel 4 moves away from the driver's seat.

The specific configuration of each part of the steering device according to the present invention is not limited to the above-described embodiment, and can be variously changed in design.

In the above embodiment, the upper portion of the steering column 1 is supported by using the holder 32 of the upper mounting portion 3a. However, the present invention is not limited thereto. When the fixed state of the upper and lower portions of the steering column 1 is released, the steering column 1 is rotated with respect to the bracket 2 or a member different from the bracket 2 by using the locking means. You may make it support as much as possible. The invention of the present application is characterized by a mounting structure at the lower part of the steering column for enabling the steering column to rotate, and the specific configuration of how to support the upper part of the steering column is particularly limited. Not something.

In the above embodiment, the steering column is not positively pulled down when a primary collision occurs. However, according to the present invention, the steering column is positively pulled down. After that, the structure may be such that the steering column is rotated. This makes it possible to move the steering wheel forward while lowering the steering wheel, which is more preferable for reducing the impact at the time of the secondary collision.

However, the present invention is not necessarily limited to automobile 1
It is not necessary that the fixed mounting state of the lower portion of the steering column be released at the time of the next collision. According to the present invention, for example, the mounting state of the steering column is not released at the time of a primary collision, and when the driver subsequently makes a secondary collision colliding with the steering wheel, the fixed mounting state is released for the first time and the steering column rotates. The configuration may be such that:

In addition, the specific configuration of each part of the steering device according to the present invention can be variously changed in design.
In the present invention, the thickness of the rear part and the front part of the lower bush is
In short, the rear part may be formed thicker than the front part, and their specific dimensions are not limited. Further, in the present invention, the fixing member to which the steering column is attached is not limited to the bracket used to attach the pedals.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a main part of an example of a steering device to which the present invention is applied.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an exploded perspective view of a main part of the steering device shown in FIG.

4 is an enlarged view of a main part showing an operation state of the mechanism shown in FIG. 2;

FIG. 5 is a side sectional view of a main part showing the operation of the steering device shown in FIG. 1;

FIG. 6 is a partially sectional side view showing an example of a conventional steering device.

7 is a partial cross-sectional side view showing an operation state of the steering device shown in FIG.

[Explanation of symbols]

 A Steering device 1 Steering column 2 Bracket (fixing member) 4 Steering wheel 5 Steering shaft 33 Lower bush 33a Rear part (of lower bush) 33b Front part (of lower bush) 34 Lower bracket

Claims (1)

[Claims] 1. A lower bush fitted externally to a lower portion of a steering column, and a lower bracket for surrounding the outer periphery of the lower bush to attach the lower portion of the steering column to a fixing member, And a lower bush is detached from the lower bracket when a force equal to or more than a predetermined value for moving the steering column relative to the fixed member downward is generated. The lower bush is characterized in that a rear portion of the steering column located rearward of the vehicle has a radial thickness greater than a front portion of the steering column located forward of the vehicle. .