JP2014162279A - Steering shaft supporting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering shaft supporting structure capable of reducing vibration at a part of a steering shaft which is supported by a vehicle body side member, without a restriction in a layout, while suppressing weight increase.SOLUTION: A bridge member 20 coupling both flange portions 31 and 31 of steering shaft brackets 30 and 30 and contacting with the flange portion 31 on an upper surface or a lower surface is equipped. The bridge member 20 has an intermediate portion 22 having predetermined thickness in a vertical direction at a position contacting with at least the flange portion 31, between both flange portions 31 and 31. A storing portion 24 is formed on the intermediate portion 22. In the storing portion 24, a single EA strap 50 which becomes resistance to relative displacement between a steering shaft 8 and an instrument member 8 and permits the relative displacement is stored.

Description

  The present invention relates to a steering shaft support structure that is provided in front of a driver's seat and supports a steering shaft that connects a steering wheel and a front wheel by a vehicle body side member in front of the driver's seat.

  The steering shaft of the vehicle converts the rotational motion generated on the steering wheel by the driver's operation into the steering motion of the front wheels. The front end is supported by the steering rack and the intermediate portion is supported by the vehicle dash panel. Generally, the rear portion that is closer to the vehicle is supported by an instrument panel member as a vehicle body side member that extends in the vehicle width direction and supports the instrument panel.

  Patent Document 1 below discloses an example of a structure in which a steering shaft is supported by an instrument panel member. In this document, the steering shaft is supported by a steering shaft bracket that hangs downward from the instrument panel member.

  By the way, in consideration of safety to the driver, for example, when a load is applied from the driver to the steering wheel in front of the vehicle (front of the vehicle along the axial direction of the steering shaft) from the driver due to a frontal collision of the vehicle. A so-called dual shaft, in which the front side of the steering shaft in the vehicle is shortened (collapsed) so as to absorb the impact on the vehicle, may be employed.

  In addition to the dual shaft described above, in order to ensure safety for the driver when a load is applied forward from the driver to the steering wheel due to a frontal collision of the vehicle, for example, it is disclosed in Patent Document 2 below. As described above, it is generally possible to relatively displace between the steering shaft and the instrument panel member, and to provide an impact absorbing member (energy absorbing plate) that absorbs the impact while deforming in accordance with the relative displacement. It is said to be the target.

JP 2011-42305 A JP 2004-338509 A

  However, in particular, when the dual shaft described above is employed, the steering shaft tends to vibrate up and down while the vehicle is traveling because the axial rigidity of the steering shaft tends to be low. In this case, if the portion where the steering shaft is supported by the instrument panel member vibrates, the vibration is transmitted to the driver as an unpleasant vibration due to the portion being close to the driver.

  In developing the steering shaft support structure, the inventor has analyzed the vibration of the steering shaft. As a result of analyzing this vibration, as shown by a two-dot chain line in FIG. 12, in the steering shaft bracket 130 (hereinafter abbreviated as the bracket 130), a drooping portion 132 that hangs downward from the instrument panel member 106, and a horizontal direction It has been found that vibration occurs in which the angle between the flange portion (fixed portion) 131 that extends to the instrument panel member 106 and is fixed to the instrument panel member 106 changes.

  The vibration described above can be reduced by setting the thickness of the bracket 130 to be thick. However, for example, when a tilt mechanism that adjusts the position of the steering shaft 108 in the tilt direction is provided, the following problems occur. Specifically, when the tilt mechanism is provided, it is necessary to form a long hole corresponding to the adjustment width of the steering shaft 108 in the hanging part 132, and the hanging part 132 becomes long. For this reason, when the plate thickness of the bracket 130 is set to be thick as described above, the weight of the bracket 130 is increased due to the fact that the hanging portion 132 is relatively long.

  It is also conceivable to reduce the vibration by providing a reinforcing portion that connects the flange portion 131 and the hanging portion 132. However, an adjustment lever that is operated when adjusting the position of the steering shaft 108 by the tilt mechanism described above is provided around the steering wheel, and a space for arranging the shock absorbing member is also required. The layout becomes substantially difficult. In addition, there is a problem that the space around the driver's knee is restricted due to the presence of the reinforcing portion.

  An object of the present invention is to provide a support structure for a steering shaft that can reduce vibration in a portion where the steering shaft is supported by a vehicle body side member without restricting the layout and suppressing an increase in weight.

  The steering shaft support structure of the present invention is a steering shaft support structure that is provided in front of the driver's seat and supports the steering shaft that connects the steering wheel and the front wheels by the vehicle body side member in front of the driver's seat, A fixed portion fixed at two locations spaced in the vehicle width direction with respect to the vehicle body side member, and a hanging portion that bends downward between the fixed portions and supports the steering shaft. A steering shaft bracket is provided, and includes a bridging member that connects the two fixing portions and whose upper surface or lower surface contacts the fixing portion, and the bridging member is at least a position in contact with the fixing portion between the two fixing portions. The intermediate portion having a predetermined thickness in the vertical direction, and a space portion is formed in the intermediate portion. Becoming resistance to relative displacement between the shaft and the vehicle body member, in which housing a single shock absorbing member to allow said relative displacement.

  According to this configuration, when the intermediate portion of the bridging member has the predetermined thickness at the position in contact with the fixed portion, vibration generated in the steering shaft bracket, that is, the portion of the portion where the steering shaft is supported by the vehicle body side member. The vibration can be reduced by the rigidity of the portion having the predetermined thickness without providing a reinforcing portion that connects the fixed portion and the hanging portion. For this reason, the reduction of the vibration can be realized without restriction of the layout.

  And since the space part which accommodates a single impact-absorbing member was formed using the site | part which has the said predetermined | prescribed thickness, the weight reduction of the whole structure can be achieved.

  In one embodiment of the present invention, the intermediate portion is constituted by a plurality of ribs formed on the bridging member.

  According to this configuration, it is possible to reduce the weight of the bridging member while securing the rigidity necessary for reducing the vibration in the bridging member by the rib.

  In one embodiment of the present invention, a hole is formed between the plurality of ribs in the bridging member.

  According to this configuration, it is possible to further reduce the weight of the bridging member while ensuring the rigidity necessary for reducing the vibration in the bridging member by the rib.

  In one embodiment of the present invention, the bridging member protrudes in the vehicle width direction from a lower protruding portion that protrudes downward from the lower surface of the intermediate portion on both sides in the vehicle width direction of the intermediate portion, and from the lower end of the lower protruding portion. A fitting groove portion that is fitted to the fixing portion is formed by the lower surface of the intermediate portion and the supporting portion, and the fixing portion is formed in the fitting groove portion. By fitting, the upper surface of the fixed portion contacts the lower surface of the intermediate portion, while the lower surface of the fixed portion contacts the upper surface of the vehicle width direction protruding portion.

  According to this configuration, the upper surface and the lower surface of the fixing portion are engaged with the lower surface of the intermediate portion and the upper surface of the protruding portion in the vehicle width direction by fitting the fitting portion into the fitting groove portion. Can be more effectively reduced. For this reason, the said vibration can be reduced more reliably by a bridging member.

  According to the present invention, it is possible to provide a steering shaft support structure that can reduce vibration in a portion where the steering shaft is supported by the vehicle body side member without restricting the layout and suppressing an increase in weight.

The side sectional view showing the support structure of the steering shaft concerning the embodiment of the present invention. The front view which shows the principal part of FIG. The perspective view of FIG. FIG. 3 is an exploded perspective view of FIG. 2. It is a perspective view which shows a bridge member, Comprising: (a) is the perspective view which looked at the bridge member from vehicle back and upper direction, (b) is the perspective view which looked at the bridge member from vehicle front and upper direction. The perspective view which looked at the steering shaft bracket and EA strap from the vehicle front and upper direction. The top view which shows the fitting state of a steering shaft bracket and a bridging member. It is a figure which shows the state of collapse of a steering shaft, Comprising: (a) is a perspective view, (b) is a side view. It is a figure which shows the state of the collapse of a steering shaft, Comprising: (a) is a perspective view, (b) is a side view. It is a figure which shows the state of the latter stage of collapse of a steering shaft, Comprising: (a) is a perspective view, (b) is a side view. Explanatory drawing for demonstrating the effect which reduces the shake of a flange part. Explanatory drawing for demonstrating the conventional problem.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a side sectional view showing a steering shaft support structure according to an embodiment of the present invention. A driver's seat 2 on which a driver is seated is disposed in a vehicle compartment 1 shown in FIG. A dash panel 3 extending in the vehicle width direction is provided at the front of the vehicle compartment 1 where the driver seat 2 is disposed. 1 is divided in the front-rear direction. Further, a floor panel 5 that extends substantially horizontally toward the rear of the vehicle and supports an instrument panel (not shown) is provided continuously from the lower end of the dash panel 3, and the driver seat 2 described above is placed on the floor panel 5. It is arranged.

  Further, an instrument panel member 6 as a vehicle body side member extending in the vehicle width direction is disposed behind the dash panel 3 described above. The instrument panel member 6 is stretched substantially horizontally in a straight line between left and right hinge pillars (not shown) as a vehicle body rigid member.

  Further, in front of the driver's seat 2, a steering shaft 8 that connects the steering wheel 7 and the front wheel indicated by a two-dot chain line in FIG. 1 is disposed, and this is supported by the instrument panel member 6 described above.

  The steering shaft 8 is rotatably supported by a cylindrical steering column 9. An inner shaft 10 is inserted on the vehicle front side of the steering column 9, and the steering shaft 8 and the steering column 9 are displaced relative to the inner shaft 10 in the axial direction. The front side of the vehicle is shortened (collapsed) in a telescopic manner.

  The steering shaft 8 converts the rotational motion generated in the steering wheel 7 by the operation of the driver into the steering motion of the front wheels, and the rotational force of the steering shaft 8 generated by the rotational motion of the steering wheel 7 is converted into the inner shaft. 10 is configured to transmit to a steering rack (not shown) on the accommodation space 4 side via a second shaft 11, a universal joint 12 and the like connected to the front end of the housing 10.

  As shown in FIGS. 1 to 4, the instrument panel member 6 described above is provided with two steering brackets 13, 13 having a substantially U-shaped cross section at a predetermined interval in the vehicle width direction. The upper part is fixed to the instrument panel member 6 by welding.

  As shown in FIG. 1, a bracket 15 is fixed to the front portion of the steering bracket 13 by bolts 14, and the front end of the inner shaft 10 described above is supported by the steering bracket 13 via the bracket 15.

  As shown in FIGS. 2 to 4, both side surfaces of a bracket 16 having a substantially U-shaped cross section are joined to both sides in the vehicle width direction of the steering column 9, and bolts 17, A pair of left and right steering shaft brackets 30, 30 (hereinafter abbreviated as bracket 30) having a substantially L shape are fixed by a nut 18 via a bridging member 20 described later.

  The brackets 30, 30 have flange portions 31, 31 that extend in the horizontal direction, and hanging portions 32, 32 that bend downward between the flange portions 31, 31. Among these, the drooping portions 32 and 32 are disposed so as to be adjacent to the outer side surface of the bracket 16 described above, and support the steering shaft 8 via the bracket 16.

  Specifically, insertion holes 16a and 16a are formed in both side surfaces of the bracket 16 as shown in FIG. 4, while the hanging portion 32 of the bracket 30 extends in the vertical direction corresponding to the insertion hole 16a. A hole 32a is bored, and a shaft member 40 that passes through the insertion hole 16a and the elongated hole 32a in the vehicle width direction is disposed.

  A lever 41 for adjusting the position of the steering wheel 8 is fixed to one end of the shaft member 40, and a screw portion (not shown) is integrally formed at the other end of the shaft member 40. A screw portion is configured to be tightened and loosened with respect to a nut 42 (see FIGS. 2 and 4) welded and fixed to (the right bracket 30 in FIGS. 2 to 4).

  A spring 43 having a substantially U-shape when viewed from the front is disposed so as to sandwich the steering column 9 on both sides in the vehicle width direction, and one end and the other end of the spring 43 are arranged on one side of the bracket 16. It is fixed to the other. The steering column 9 is always urged upward by the urging force of the spring 43.

  In this embodiment, the steering shaft 8 is supported by the hanging portion 32 (bracket 30) via the steering column 9, the bracket 16, and the shaft member 40 described above, and further, the steering bracket 13 and the bridging member 20 are connected. Via the instrument panel member 6.

  And the tilt mechanism is comprised by the long hole 32a of the bracket 30, the shaft member 40, the lever 41, and the nut 42, and after loosening the above-mentioned screw part via the lever 41 and the shaft member 40 for position adjustment, When the steering column 9 is tilted and operated along the elongated hole 32a in the vertical direction against the biasing force of the spring 43, the position of the steering wheel 7 and the steering shaft 8 can be adjusted in the tilt direction. When the shaft member 40 is tightened after the position adjustment in the tilt direction, the steering wheel 7 and the steering shaft 8 can be arranged at desired positions according to the physique of the driver seated on the driver seat 2. ing.

  By the way, the bridging member 20 described above is made of aluminum from the viewpoint of weight reduction, and is formed by casting. In this bridging member 20, as shown in FIGS. 2 to 5, the side portions 21 and 21 on both sides in the vehicle width direction are fixed to the steering bracket 13 by bolts 17 and nuts 18. An insertion hole 21a through which the bolt 17 is inserted is formed.

  On the other hand, the intermediate portion 22 located between the side portions 21 on both sides in the vehicle width direction is formed in a substantially triangular shape in front view so that the thickness in the vertical direction increases from the side portion 21 toward the center portion in the vehicle width direction. The plurality of ribs 23, 23,... And the vehicle width direction center part of the intermediate part 22 is formed so that the thickness of an up-down direction may become the thickest, and the accommodating part which accommodates the single EA strap 50 mentioned later in this vehicle width direction center part 24 is formed.

  Further, as shown in FIG. 5, in the intermediate portion 22, three ribs 23 are arranged in front and rear on both sides in the vehicle width direction, and holes 22 a and 22 a are formed between the ribs 23 and 23. Has been. Further, holes 22b and 22b are formed at positions in the vehicle front-rear direction in which the ribs 23 are not formed, that is, positions between the ribs 23 and 23, on the upper and lower surfaces of the middle portion in the vehicle width direction of the intermediate portion 22. ing. Thus, by drilling the holes 22a and 22b between the ribs 23, a load transmission path extending in the vehicle width direction is formed at a position corresponding to the ribs 23. With this load transmission path, A load can be transmitted between the side portions 21 and 21.

  Further, as shown in FIG. 2, the both side portions 21, 21 have a lower protruding portion 25 a that protrudes downward from the lower surface of the intermediate portion 22 and a vehicle width from the lower protruding portion 25 a at both sides and the front end in the vehicle width direction. A vehicle width direction projecting portion 25b projecting in the direction is integrally formed, and a support portion 25 is formed by both the projecting portions 25a and 25b. The support portion 25 and the lower surface of the intermediate portion 22 form a fitting groove portion 26 across both sides in the vehicle width direction and the front end.

  On the other hand, as shown in FIGS. 4 and 6, the flange portion 31 of the bracket 30 is formed with a fitting recess 31 a in which the vehicle rear side is opened. The edge of the fitting recess 31a is fitted into the fitting groove 26 of the bridging member 20 as shown in FIG. 7 so that the pair of left and right brackets 30 and 30 are connected to each other via the bridging member 20. These brackets 30 are fixed to the instrument panel member 6 via the bridging member 20.

  And in the state which the edge of the fitting recessed part 31a of the flange part 31 fitted in the fitting groove part 26 of the bridging member 20, while the upper surface of the flange part 31 contacts the lower surface of the intermediate part 22, on the other hand, The lower surface is in contact with the upper surface of the vehicle width direction protrusion 25b. Here, in the intermediate portion 22 described above, the thickness of the rib 23 is set so that the intermediate portion 22 has a predetermined thickness in the vertical direction at least at a position where it contacts the flange portion 31.

  As shown in FIG. 6, the EA strap 50 includes a base 51 on the front side of the vehicle, a U-shaped plate portion 52 that protrudes rearward from the center of the rear end of the base 51 and is accommodated in the accommodating portion 24. It is comprised by.

  Among these, the base 51 has both side surfaces in the vehicle width direction joined to the inner surface in the vehicle width direction of the hanging portion 32 of the bracket 30. A slit 51a for fitting the upper portion of the spring 43 is formed on the upper surface of the base portion 51. The upper portion of the spring 43 has a slit 51a, as shown by a two-dot chain line in FIG. And it is regulated at a predetermined position by a regulating piece 33 formed at the front end of the bracket 31.

  The U-shaped plate portion 52 is accommodated in the accommodating portion 24 in a state where the middle portion thereof is folded in an arc shape, and the folded portion at the rear end protrudes from the accommodating portion 24 in a normal state. A fitting convex portion 52 a is formed at the free end of the U-shaped plate portion 52, and the fitting convex portion 52 a is formed at the bridging member 20 in the front portion of the hole 22 b in the vehicle. 22c is fitted.

  By the way, when the steering shaft 8 is assembled to the vehicle body, first, the above-described steering shaft 8 (steering column 9), bridging member 20, bracket 30, EA strap 50, and the like are sub-assembled. And the steering shaft 8 is assembled | attached to a vehicle body by fastening the bridging member 20 to the steering bracket 13 with the volt | bolt 17 and the nut 18. FIG.

Next, behavior of the steering shaft 8 and its surroundings at the time of a frontal collision of the vehicle will be described with reference to FIGS.
When a load is applied in front of the vehicle to the steering wheel 7 (see FIG. 1) from a driver seated in the driver's seat 2 (see FIG. 1) due to a frontal collision of the vehicle V, the vehicle V passes through the steering shaft 8, the steering column 9, and the like. The load is transmitted to the bracket 30. As a result, the bracket 30 is displaced relative to the bridging member 20 forward from the position of the initial state shown in FIG. 8 as shown in FIG. Specifically, the bracket 30 slides forward with respect to the bridging member 20 by the edge of the fitting recess 31 a of the bracket 30 being guided by the fitting groove 26 of the bridging member 20.

  Further, by sliding the bracket 30 forward of the vehicle, the steering shaft 8 and the steering column 9 can be relatively displaced forward of the vehicle with respect to the instrument panel member 6 and the inner shaft 10 as shown in FIG. . Due to the relative displacement of the steering shaft 8 and the steering column 9, the vehicle front side of the steering shaft 8 is shortened (collapsed) in a telescopic manner as shown in FIG. 9, and the impact on the driver is absorbed by this collapse.

  Furthermore, since relative displacement has occurred between the bridging member 20 and the bracket 30, in the EA strap 50, the relative position between the base portion 51 and the fitting convex portion 52 a of the U-shaped plate portion 52 changes. become. At this time, in the U-shaped plate portion 52, the lower portion on the base 51 side is pulled forward of the vehicle, so that the position of the folded portion at the rear end is moved forward of the vehicle as shown in FIG. The deformation of the U-shaped plate portion 52 further absorbs the impact on the driver. Due to the deformation of the U-shaped plate portion 52, the EA strap 50 is resisting relative displacement between the bridging member 20 and the bracket 30, that is, relative displacement between the instrument panel member 6 and the steering shaft 8. , Function as an impact absorbing member that allows the relative displacement.

  When the driver further applies the load to the steering wheel 7 (see FIG. 1), as shown in FIG. 10, the relative displacement amount between the bridge member 20 and the bracket 30 and the vehicle of the steering shaft 8 The shortened width (collapse amount) on the front side further increases. Then, as the relative displacement amount increases, the U-shaped plate portion 52 is further deformed, and as a result, the position of the folded portion further moves forward of the vehicle.

  By the way, the present inventor has analyzed the behavior of the steering shaft 8 and its surroundings when the vehicle is traveling. As a result of analyzing this behavior, the vibration generated in the bracket 30, that is, the steering shaft 8 is supported by the instrument panel member 6 when the intermediate portion 22 has the predetermined thickness at the position in contact with the flange portion 31. It has been found that the vibration of the part can be reduced by the rigidity of the part having the predetermined thickness.

  Further, in particular, the flange portion 31 as shown by a two-dot chain line in FIG. 11A because the upper surface is in contact with the lower surface of the intermediate portion 22 by fitting the flange portion 31 to the fitting groove portion 26. It has been found that the upward swing of can be reduced more effectively. Further, since the lower surface of the flange portion 31 is in contact with the upper surface of the vehicle width direction protruding portion 25b, the downward deflection of the flange portion 31 as shown by a two-dot chain line in FIG. It was also found that it can be reduced.

  In the present embodiment, as described above, the vibration generated in the bracket 30 when the intermediate portion 22 of the bridging member 20 has the predetermined thickness at the position in contact with the flange portion 31, that is, the steering shaft 8 is the instrument panel member. The vibration of the portion supported by 6 can be reduced by the rigidity of the portion having the predetermined thickness without providing a reinforcing portion that connects the flange portion 31 and the hanging portion 32. For this reason, the reduction of the vibration can be realized without restriction of the layout.

  And since the accommodating part 24 which accommodates the single EA strap 50 using the site | part which has the said predetermined | prescribed thickness was formed, the weight reduction of the whole structure can be achieved.

  In addition, by configuring the intermediate portion 22 with the plurality of ribs 23, it is possible to reduce the weight of the bridging member 20 while securing the rigidity necessary for reducing the vibration in the bridging member 20 by the ribs 23.

  In addition, since the holes 22 a and 22 b are formed between the plurality of ribs 23 in the bridging member 20, the bridging member 20 secures the rigidity necessary for reducing the vibration by the rib 23, while the bridging member 20 has the rigidity of the bridging member 20. Further weight reduction can be achieved.

  Further, by fitting the flange portion 31 into the fitting groove portion 26, the upper surface and the lower surface are in contact with the lower surface of the intermediate portion 22 and the upper surface of the vehicle width direction protruding portion 25 b, respectively. The downward swing can be reduced more effectively. For this reason, the vibration can be more reliably reduced by the bridging member 20.

  In the above-described embodiment, the lower surface of the bridging member 20 (intermediate portion 22) is mainly in contact with the flange 31. However, the present invention is not necessarily limited to this, and the bridging member (intermediate portion) is mainly used. The configuration may be such that the upper surface of the portion) contacts the flange portion.

In correspondence between the configuration of the present invention and the above-described embodiment,
The vehicle body side member of the present invention corresponds to the instrument panel member 6,
Similarly,
The fixing part corresponds to the flange part 31,
The space portion corresponds to the accommodating portion 24,
The shock absorbing member corresponds to the EA strap 50,
The present invention is not limited only to the configuration of the above-described embodiment, and many embodiments can be obtained.

2 ... Driver seat 6 ... Instrument panel member 7 ... Steering wheel 8 ... Steering shaft 20 ... Bridging member 22 ... Intermediate part 22a, 22b ... Hole 23 ... Rib 24 ... Housing part 25 ... Supporting part 25a ... Downward projecting part 25b ... Vehicle width Direction protrusion 26 ... fitting groove 30 ... steering shaft bracket 31 ... flange 32 ... hanging part 50 ... EA strap

Claims (4)

A steering shaft support structure that is provided in front of the driver's seat and supports the steering shaft that connects the steering wheel and the front wheels by the vehicle body side member in front of the driver's seat,
A fixing portion that is fixed at two locations spaced in the vehicle width direction with respect to the vehicle body side member;
A steering shaft bracket having a hanging portion that bends downward between the fixed portions and supports the steering shaft;
A bridge member that connects the two fixing portions and has an upper surface or a lower surface in contact with the fixing portion,
The bridging member has an intermediate portion having a predetermined thickness in the vertical direction at least at a position in contact with the fixed portion between the fixed portions.
A space portion is formed in the intermediate portion,
A steering shaft support structure in which a single shock absorbing member that accommodates the relative displacement while accommodating the relative displacement between the steering shaft and the vehicle body side member is accommodated in the space. The steering shaft support structure according to claim 1, wherein the intermediate portion includes a plurality of ribs formed on the bridging member. The steering shaft support structure according to claim 2, wherein a hole is formed between the plurality of ribs in the bridging member. The bridging member includes a lower projecting portion that projects downward from the lower surface of the intermediate portion on both sides in the vehicle width direction of the intermediate portion, and a vehicle width direction projecting portion that projects in the vehicle width direction from the lower end of the lower projecting portion. Having a support,
The lower surface of the intermediate part and the support part form a fitting groove part that fits the fixed part,
While the fixing portion is fitted into the fitting groove portion, the upper surface of the fixing portion is in contact with the lower surface of the intermediate portion,
The steering shaft support structure according to any one of claims 1 to 3, wherein a lower surface of the fixed portion is in contact with an upper surface of the vehicle width direction protruding portion.

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