JP3561165B2 - Steering device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a steering device, and more particularly to a steering device suitable for obtaining a shock absorbing function when a driver collides with a steering wheel (secondary collision) following a forward collision (primary collision) of an automobile. .
[0002]
[Prior art]
FIG. 6 shows an example of a conventional steering device. 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 lower bracket 92 attached to a fixing member 91 surrounds the outer periphery of the lower bush 90. This is a means for holding. The lower bush 90 is in a state of being press-fitted between the steering column 9 and the cylindrical portion of the lower bracket 92, and an engaging portion 90 a provided at a lower end of the lower bush 90 is provided at a lower end of the steering column 9. Surface.
[0003]
In the steering device having such a structure, when a force F2 equal to or more than a predetermined value for lowering the steering column 9 relative to the fixed member 91 is generated, as shown in FIG. , And the steering column 9 can be lowered relative to the fixed member 91. Of course, this is based on the premise that when the upper portion of the steering column 9 is fixedly attached to, for example, the fixing member 91, the upper attaching portion 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]
[Problems to be solved by the invention]
However, in the conventional steering apparatus described above, only the operation of pulling the steering column 9 downward relative to the fixed member 91 can be obtained, and from the viewpoint of reducing the impact at the time of the secondary collision, the improvement still needs to be made. There was room. 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 rotates the steering column after the detachment as a means for enhancing the shock absorbing action at the time of the secondary collision. The idea was to move the steering wheel forward of the vehicle by rotating the steering column (Japanese Patent Application No. 10-360402). However, in the above-described conventional structure, as shown in FIG. 7, even after the steering column 9 is detached from the fixing member 91, 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, even if the steering column 9 is rotated in the direction in which the steering wheel 96 moves forward (the direction of the arrow N5) after the steering column 9 is detached from the fixed member 91, the lower bracket 92 becomes an obstacle, Actually, such an operation could not be performed.
[0005]
The present invention was conceived in view of such circumstances, and enables a rotation operation of a steering column when an attached state of a steering column is released, and a steering wheel based on the rotation operation of the steering column. It is an object of the present invention to provide a steering device capable of reducing the impact at the time of a secondary collision by the forward motion of the vehicle.
[0006]
DISCLOSURE OF THE INVENTION
In order to solve the above problems, the present invention employs the following technical means.
[0007]
A steering device provided by the present invention includes: 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. The lower bush is configured to be detached from the lower bracket when a force equal to or more than a predetermined value is generated to move the steering column relatively downward with respect to the fixed member. The steering device, wherein the lower bush is such that a rear portion of the steering column located rearward of the vehicle has a greater thickness in a radial direction than a front portion of the steering column located forward of the vehicle , and Of the lower bracket, between the above steering column The portion of the lower bush that sandwiches the rear portion has a greater distance from the outer peripheral surface of the steering column than the portion that sandwiches the front portion of the lower bush, and when the lower bush separates from the lower bracket, The lower part of the steering column is movable rearward in the gap formed inside the lower bracket.
[0008]
In the present invention, the thickness (wall thickness) in the radial direction of the lower bush that is externally fitted to the lower part of the steering column is not uniform at all places, and the rear part of the steering column located at the rear of the vehicle is more than the front part located at the front of the vehicle. Also have a large thickness. 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 sandwiching this rear portion and facing the rear of the vehicle is limited by the thickness of the rear portion of the lower bush. The distance between the inner surface of 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 way, the lower portion of the steering column can be moved rearward in the gap within the gap. Therefore, when the fixed mounting state of the lower portion of the steering column is released, if the upper portion of the steering column is supported by, for example, an appropriate means that allows the rotating operation of the steering column, the steering column can be centered on the supporting portion. Can be rotated in the direction in which the upper end moves forward of the vehicle.
[0009]
As described above, according to the present invention, when the fixed mounting state of the lower portion of the steering column is released, the steering column can be rotated in a direction in which the upper end moves forward of the vehicle. Therefore, it is suitable for reducing the impact at the time of the secondary collision by moving the steering wheel to the front of the vehicle based on the rotation operation of the steering column. In particular, in the present invention, the lower bracket can rotate the steering column while enclosing the lower portion of the steering column, so that 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 components is not increased as compared with the conventional case, and the manufacture 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]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.
[0012]
FIG. 1 is a side sectional view of a main 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. 5 is a side sectional view of a main part showing the operation of the steering device shown in FIG. In addition, in the figures after FIG. 1, the arrow Fr indicates the front of the vehicle, and the arrow Up indicates the upper side in the vehicle height direction.
[0013]
In FIG. 1, a steering apparatus 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 3a, 3b for mounting the steering column 1 to the bracket 2. It is comprised including. 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.
[0014]
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 its axis. Although not shown in the drawing, for example, a substantially cylindrical upper member is provided. It is constructed by combining a column and a lower column. 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 part of the floor at the front of the vehicle via a plurality of universal joints 50 and the like. The gear box 51 is provided at a position closer to the rear of the vehicle than the bracket 2, and does not move backward to the rear of the vehicle prior to the bracket 2 when a front collision of the vehicle occurs.
[0015]
The bracket 2 is formed by, for example, 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 the floor panel 71 using bolts 73 or the like, and stands up above the fixed bracket 72. However, the bracket 2 is provided with an inclined portion 20 extending 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 the reinforcement 75 via a stay 74. The apparel reinforcement 75 is a member having a large rigidity that forms the lower edge portion 77 of the front window portion 76, and corresponds to a cowl or a member for reinforcing the cowl in a general automobile.
[0016]
The bracket 2 is also connected to the cross member 76 via a stay 78, so that the fixing strength of the bracket 2 is increased. However, the stay 78 is formed such that when the cross member 76 retreats at the time of a forward collision of the vehicle, the stay 78 itself bends relatively easily so as not to exert a large force for pressing the bracket 2 rearward of the vehicle. ing. The cross member 76 is a member located in front of the bracket 2 in the vehicle and extending 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.
[0017]
2 and 3, the upper mounting portion 3a is provided with the bolt insertion holes 12a and 30a after the upper bracket 12 welded to the upper portion of the steering column 1 is sandwiched by the clamp pieces 30 having a substantially U-shaped cross section. Has a structure in which the upper bracket 12 is fastened to the seat portion 20a of the inclined portion 20 by a bolt 31 inserted into the upper portion and a nut 31a screwed thereto. Further, a holder 32 surrounding the upper outer peripheral surface of the steering column 1 is also assembled using the bolt 31.
[0018]
The clamp piece 30 clamps the upper bracket 12 from both sides indicated by arrows N1 and N1 by the tightening force of the bolt 31 and the nut 31a, and the steering column 1 is fixed by the clamp force. The bolt insertion hole 12a of the upper bracket 12 is a notch hole that is open at the upper end side. Therefore, in the mounting portion 3a, as shown in FIG. 4, a force F1 for moving the inclined portion 20 of the bracket 2 obliquely upward relative to the steering column 1 is generated, and the force F1 becomes equal to or more than a certain value. When this happens, the upper bracket 12 is detached downward from the clamp piece 30, and 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. 2, since the upper portion of the steering column 1 can be fixed to the bracket 2 and attached without the holder 32, the holder 32 holds the steering column 1 in a normal state. It is not necessary to have a function for fixing to the bracket 2.
[0019]
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. The lower bush 33 is made of, for example, a synthetic resin and has an elliptical outer shape in a front view, as is well shown 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 33c of the lower bush 33 is different. Specifically, when the lower bush 33 is externally fitted to the steering column 1, as shown in FIG. 2, the thickness ta of the rear portion 33a located rearward of the vehicle with respect to the steering column 1 is different from that of the other portions. 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. An engaging portion 33d that engages with the front end surface of the lower end 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.
[0020]
As shown in FIG. 3, the lower bracket 34 is configured by providing a plate-shaped fixing plate portion 34 b having a bolt insertion hole 34 c on the outer surface of a cylindrical portion 34 a, and using a bolt 35. By fixing the fixing plate portion 34b to the inclined portion 20 of the bracket 2, the fixed plate portion 34b is fixedly attached to the inclined portion 20. The tubular portion 34a has a shape corresponding to the lower bush 33, and the lower bush 33 is press-fitted into a gap between the tubular portion 34a and the lower portion of the steering column 1. 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 bush 33 is detached downward from the cylindrical portion 34a of the lower bracket 34. The fixed state of the lower portion of the steering column 1 is released.
[0021]
Next, the operation of the steering device A will be described.
[0022]
First, as shown in FIG. 5, when the automobile causes a frontal collision and a very large load F is applied to the front of the vehicle body from the front thereof, the front of the vehicle body crashes. Pressed to the rear of the vehicle. 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 rises upward in which the inclined portion 20 extends. A force F1 is generated to cause the deformation F1. 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 having a fixed lower end, and exhibits a resistance to the force F1. 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.
[0023]
However, since 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, the entire steering column 1 is supported by the holder 32 so as not to drop onto the floor panel 71. You can keep. On the other hand, as for the lower part of the steering column 1, the lower bush 33 is detached from the lower bracket 34, so that the lower surface 1 a of the lower part of the steering column 1 and the inner surface 34 a ′ of the cylindrical part 34 a facing the lower part 1 a A gap S having a considerably large width equal to the thickness ta of the rear portion 33a of the lower bush 33 is formed. Therefore, the lower portion of the steering column 1 has a margin to move toward the rear of the vehicle indicated by the arrow N4 in a range until the rear surface 1a comes into contact with the inner surface 34a 'of the tubular portion 34a.
[0024]
For this reason, as shown in FIG. 5, the steering column 1 is rotatable in the direction of the arrow N2 about the 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 the 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. Also, 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. 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.
[0025]
The specific configuration of each part of the steering device according to the present invention is not limited to the above-described embodiment, and various design changes can be made.
[0026]
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 to this. When the fixed mounting state of the upper and lower portions of the steering column 1 is released, the steering column 1 is rotatably supported by the bracket 2 or another member other than the bracket 2 by using the locking means. You may make it do. The present invention is characterized by a mounting structure at a lower portion of the steering column for enabling the steering column to rotate, and a specific configuration of how to support the upper portion of the steering column is particularly limited. Not something.
[0027]
Further, in the above-described embodiment, the steering column is not positively pulled downward when a primary collision occurs. However, in the present invention, the steering column is positively pulled downward. The structure which rotates the steering column may be used. This makes it possible to move the steering wheel forward while lowering the steering wheel, which is more preferable in reducing the impact at the time of a secondary collision.
[0028]
However, the present invention is not necessarily required to be configured so that the fixed mounting state of the lower portion of the steering column is released at the time of the primary collision of the vehicle. According to the present invention, for example, at the time of a primary collision, the mounted state of the steering column is not released, and when the driver subsequently makes a secondary collision colliding with the steering wheel, the fixed mounted state is released for the first time and the steering column rotates. The configuration may be such that
[0029]
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 portion and the front portion of the lower bush is not particularly limited as long as the rear portion is formed to be thicker than the front portion. 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 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. 2;
FIG. 5 is a side sectional view of a main part showing an 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 sectional side view showing an operation state of the steering device shown in FIG. 6;
[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 (of lower bush)
34 lower bracket

Claims (1)

A lower bush externally fitted to the lower portion of the steering column, and a lower bracket for mounting the lower portion of the steering column to a fixed member by surrounding the outer periphery of the lower bush; and A steering device, wherein the lower bush is configured to be detached from the lower bracket when a force equal to or more than a predetermined value that attempts to relatively move the fixing member downward is generated,
The lower bush has a greater thickness in the 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 ,
In the lower bracket, a portion sandwiching the rear portion of the lower bush between the steering bracket and the steering column has a greater distance from an outer peripheral surface of the steering column than a portion sandwiching the front portion of the lower bush. ,
When the lower bush is detached from the lower bracket, a lower portion of the steering column is movable rearward of the vehicle within a gap formed inside the lower bracket .

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