Steering column device

A steering column device includes: an outer column having a tubular shape; an inner column movably inserted in the outer column; a restricting member provided through a tubular wall at a lower section of the outer column in such a way as to be capable of coming in and out of the tubular wall in the thickness direction thereof; and a load absorbing wire including first ends engageable with the restricting member and a second end supported on the inner column side, and configured to be deformed by movement of the second end toward the vehicle front side together with the inner column upon application of a load of a preset value or greater to the inner column toward the vehicle front side, to thereby absorb the load.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2016-063037, filed on Mar. 28, 2016, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a steering column device capable of telescopic operation.

BACKGROUND ART

As a conventional steering column device, there has been one including a vehicle-body attachment bracket configured to be fixed to a vehicle body, a pair of sidewalls provided to extend downward from this vehicle-body attachment bracket, and a steering column disposed between this pair of sidewalls (see Patent Literature 1: WO2012/000593A1, for example).

The steering column in Patent Literature 1 includes an outer column fixed to the vehicle-body side, an inner column arranged to be movable inside the outer column in the axial direction (vehicle longitudinal direction), and a fastener configured to fasten the inner column to the outer column. A restricting member placed on the inner column comes into contact with a locking member placed on an operating shaft for the fastener to thereby define the range of movement of the inner column (telescopic-position adjustment range).

Moreover, in a collision of the vehicle, a load of a preset value or greater may be applied to the restricting member, and a locking plate engaging with the locking member may fracture the restricting member. This fracture allows the inner column to move forward to the outside of the telescopic movement range.

SUMMARY

Meanwhile, in Patent Literature 1, the restricting member is fractured in the middle of contraction of the inner column. This leads to a problem that the impact absorption load abruptly increases in the middle of absorption of the impact energy in the collision of the vehicle.

Thus in view of the above circumstance, an object of the present invention is to provide a steering column device that suppresses abrupt increase in impact absorption load in the middle of absorption of impact energy.

A steering column device according to the present invention includes: an outer column having a tubular shape and arranged along a vehicle longitudinal direction; an inner column inserted in the outer column in such a way as to be movable in a tube-axis direction and capable of telescopic operation; a restricting member provided through a tubular wall at a lower section of the outer column in such a way as to be capable of coming in and out of the tubular wall in a thickness direction thereof, and configured to restrict a front-end position of the inner column in a direction of telescopic contraction thereof with a stopper part; and a load absorbing wire including a first end engageable with the restricting member and a second end supported on the inner column side, and configured to be deformed by movement of the second end toward a vehicle front side together with the inner column upon application of a load of a preset value or greater to the inner column toward the vehicle front side, to thereby absorb the load. The stopper part of the restricting member is normally disposed to project to a radially inner side of an inner peripheral surface of the tubular wall of the outer column. The stopper part of the restricting member is capable of being moved by the load absorbing wire to a position on a radially outer side of the inner peripheral surface of the tubular wall of the outer column when the load absorbing wire is deformed upon application of a load of a preset value or greater to the inner column toward the vehicle front side.

In the steering column device according to the present invention, when the inner column moves toward the vehicle front side in a collision of the vehicle, the stopper part of the restricting member sinks to a radially outer side of the inner peripheral surface of the tubular wall of the outer column. In this way, the front end of the inner column can avoid contact with the stopper part of the restricting member and move toward the front side beyond the stopper part. This makes it possible to suppress abrupt increase in impact absorption load in the middle of absorption of the impact energy.

DESCRIPTION OF EMBODIMENTS

Some embodiments of the present invention will be described below with reference to the drawings. Note that, in the drawings, FR denotes a vehicle front side and RR denotes a vehicle rear side.

First Embodiment

As illustrated inFIGS. 1 to 4, a steering column device1according to a first embodiment is a manual-type steering column device1. The steering column device1includes: an attachment bracket2for fixing the steering column device1to a vehicle body; an outer column7supported to the attachment bracket2in such a way as to be swingable in the vehicle vertical direction (capable of adjusting its tilt position); an inner column9supported to the outer column7in such a way as to be movable in the vehicle longitudinal direction (capable of adjusting its telescopic position).

The steering column device1further includes: a locking mechanism60configured to fasten the attachment bracket2, the outer column7, and the inner column9; an energy absorbing mechanism61configured to absorb impact energy in a secondary collision; and a telescopic-position restricting mechanism62configured to define an adjustment range for the position of the inner column9relative to the outer column7in the vehicle longitudinal direction (telescopic position).

The inner column9is configured to be inserted in the outer column7in such a way as to be movable in the tube-axis direction, thereby allowing telescopic operation. Specifically, in a locked state, the front-rear position of the inner column9relative to the outer column7is locked (fixed) by a locking member68. In an unlocked state, an operating lever15is pushed down, so that the lock is released and the front-rear position of the inner column9relative to the outer column7can be changed. Then, after the front-rear position of the inner column9is set to a proper position, the operating lever15is pushed up and locked, so that the front-rear position of the inner column9relative to the outer column7is fixed.

The attachment bracket2includes a front fixing part3and a rear fixing part5configured to be fixed to the vehicle body's steering member (not illustrated). The front fixing part3includes a pivot portion17configured to pivotally support the outer column7such that the outer column7can be swung, and the rear fixing part5includes a pair of hanging portions hanging from its right and left edges. Both hanging portions are provided with a tilt slot bored to define a tilt-position adjustment range along the vehicle vertical direction (tilt direction). The tilt slot is formed of an elongated hole arched about the pivot portion.

The outer column7is formed in a tubular shape and arranged between the pair of hanging portions of the attachment bracket2along the vehicle longitudinal direction. The outer column7has its front end portion pivotally supported to the pivot portion17of the front fixing part3of the attachment bracket2with a bolt. In this way, the rear end side of the outer column7can swing in the vehicle vertical direction.

Moreover, as illustrated inFIGS. 1 and 2, the outer column7includes a slit55penetrating through the lower surface of a tubular wall21and extending from the rear edge along the tube-axis direction. The dimension of the slit55in the tube-axis direction is set such that the slit55extends to a portion of the outer column7overlapping the front end of the inner jacket9in a state where the inner jacket9, inserted in the rear end of the outer column7, is fully contracted by absorbing an impact and moved forward relative to the outer column7.

As illustrated inFIG. 2, a pair of clamp parts63are provided to extend from the opposite edges of the slit55extending along the tube-axis direction. Both clamp parts63are provided to extend along the vehicle vertical direction at sections located on the rear end side of the slit55and facing the hanging portions of the rear fixing part5. Moreover, an operating shaft64penetrates through both clamp parts63in such a way as to be turnable about its axis.

A pair of guiderail supporting parts65are provided to extend downward from front end portions of the opposite edges of the slit55extending along the tube-axis direction, and a supporting pin66is laid between the guiderail supporting parts65. A later-described guiderail67is swingably supported on the supporting pin66. A pair of stopper parts31are provided to extend downward on the rear side of the guiderail supporting parts65, and a later-described restricting member11is held between the stopper parts.

The inner column9is formed in a tubular shape and inserted in the tube of the outer column7in such a way as to be movable in the tube-axis direction. A steering shaft10is rotatably supported inside the tubes of the inner column9and the outer column7. The steering shaft10includes a lower shaft10L housed in the outer column7and an upper shaft10U housed in the inner column9. The upper shaft10U and the lower shaft10L are coupled to each other with a spline(s). Thus, the upper shaft10U and the lower shaft10L can rotate together about an axis, and the upper shaft10U can move relative to the lower shaft10L in the direction of the axis.

As illustrated inFIGS. 2 and 3, the locking mechanism60includes the operating lever15, the operating shaft64, the guiderail67, the locking member68, a locked member69, and a cam member57.

The operating shaft64has a shaft shape, penetrates through the tilt slots in both hanging portions of the attachment bracket2and both clamp parts63of the outer column7along the vehicle width direction, and is supported to the clamp parts63in such a way as to be turnable about its axis.

The operating lever15is disposed on the operating shaft64.

The front end of the guiderail67is pivotally supported to the guiderail supporting parts65, provided on the outer periphery of the outer column7, with the supporting pin66such that the guiderail67can be swung, while the rear end side is held between the locking member68and the cam member57. In this case, the cam member57presses the locking member68against the locked member69via the guiderail67. With such a configuration, a force (frictional force) in the direction of rotation of the cam member57is not transmitted to the locking member68, and only a force in the radial direction is transmitted to the locking member68. In this way, the inner column9can be fixed without being displaced in the tube-axis direction from the desired position when a locking operation is performed.

As illustrated inFIG. 3, the locking member68forms a row of claws configured to engage with the locked member69, and a wire-member catching part70is formed in the locking member68. Also, a spring member71formed of a leaf spring is disposed between the locking member68and the locked member69.

The wire-member catching part70is a recess provided in the upper surface of the locking member68, and supports a second end49of a load absorbing wire13.

As illustrated inFIG. 3, the locked member69is fixed to the outer peripheral surface of the inner column9along the tube-axis direction. Also, in the locked member69, a plurality of catching recesses (locking holes) are formed opening successively in the longitudinal direction.

As illustrated inFIGS. 2 and 3, the cam member57is formed in a cylindrical shape, and on the outer peripheral surface of its center in the axial direction is formed a driven cam part protruding in the radial direction. Further, a rubbing part is formed on the outer peripheral surface of each end portion of the cam member57in the axial direction, and the load absorbing wire13is configured to be rubbed against the rubbing part.

As illustrated also inFIG. 5, the restricting member11is provided through the tubular wall21at a lower section of the outer column7in such a way as to be capable of coming in and out of the tubular wall21in its thickness direction. This restricting member11is configured to restrict the front-end position of the inner column9in the direction of telescopic contraction thereof and is arranged to be releasable from the outer column7. Specifically, the restricting member11integrally includes a lower holding part23extending in the vehicle width direction, a linking part25extending upward from a center portion of the lower holding part23in the vehicle width direction, an upper holding part27linked to the lower holding part23by the linking part25, an upper extension part29provided on the upper holding part27, and a stopper part31formed at the front end of the upper extension part29. Further, this stopper part31is held in the tubular wall21at the lower section of the outer column7. Furthermore, the upper surfaces of the right and left sides of the lower holding part23are formed as flat wire push surfaces26, and the vehicle rear side of the stopper part31is formed as a contact surface33. This contact surface33restricts the front-end position of the inner column9in the direction of telescopic contraction thereof. Specifically, the front-rear position at which a lower portion of the front end of the inner column9contacts the contact surface33in telescopic adjustment is the foremost position in the direction of telescopic contraction. Moreover, a pair of wire insertion parts35into which to insert the load absorbing wire13are formed in the lower holding part23by the right and left of the linking part25. Meanwhile, in total four protrusions37in the shape of a triangular prism extending in the vertical direction are provided on right and left portions of the front surface of the lower holding part23and right and left portions of the rear surface of the lower holding part23.

The above load absorbing wire13is curved in a J-shape in a side view. Specifically, the load absorbing wire13is integrally formed of: a pair of right and left main parts41extending straight in the vehicle longitudinal direction substantially in parallel to the outer column7; bent parts43(first ends45) formed in L-shapes in a plan view and bent outward in directions crossing the outer column7from the front ends of the main parts41on the vehicle front side; curved parts47formed in a U-shape in the side view and curved upward from the rear ends of the main parts41on the vehicle rear side; and the second end49extending toward the vehicle front side from the curved parts47with the tips formed integrally with each other in the vehicle width direction. Note that the second end49of the load absorbing wire13is fixed to the inner column9by the wire-member catching part70during the locked state. Also, at the lower section of the outer column7, a wire holding part51protruding downward is provided. In the wire holding part51, notches53are formed with their vehicle rear sides open to be capable of housing the bent parts43of the load absorbing wire13. Further, as illustrated inFIG. 4, the slit55, which has a rectangular shape along the front-rear direction, is formed in the lower section of the outer column7. Furthermore, as illustrated inFIG. 3, the cam member57projects downward from the lower section of the outer column7. The load absorbing wire13is routed under this cam member57. In a collision of the vehicle, the inner column9moves toward the front side together with the locking member68and the second end49of the load absorbing wire13. Then, the curved parts47of the load absorbing wire13are pulled around the outer peripheral surface of the cam member57, and thereafter the curved parts47and the main parts41of the load absorbing wire13are rubbed against the rubbing parts on the outer peripheral surface of the cam member57and deformed accordingly. As a result, the impact energy is absorbed.

Next, movement of the restricting member11in a collision of the vehicle will be described with reference toFIGS. 6A to 6C.

As illustrated inFIG. 6A, during normal vehicle travel, the stopper part31of the restricting member11is disposed to project to a radially inner side (upper side inFIG. 6A) of an inner peripheral surface59of the tubular wall21of the outer column7. With the triangular-prism protrusions37, illustrated inFIG. 5, biting into the wire holding part51at the lower section of the outer column7, the restricting member11is held in the wire holding part51and does not get released by its own weight. Also, the bent parts43of the load absorbing wire13are housed in the notches53of the wire holding part51.

As illustrated inFIG. 6B, when a load of a preset value or greater is applied to the inner column9toward the vehicle front side in a collision of the vehicle, the inner column9, described with reference toFIG. 3, moves toward the front side together with the locking member68and the second end49of the load absorbing wire13. Then, the main parts41of the load absorbing wire13turn counterclockwise in the side view about the cam member57such that the bent parts43sink. At the same time, as the bent parts43of the load absorbing wire13exit the notches53of the wire holding part51and move toward the rear side, the bent parts43slide on the wire push surfaces26of the restricting member11while pushing down the wire push surfaces26. Consequently, the restricting member11is released from the wire holding part51of the outer column7, as illustrated inFIGS. 6B and 6C.

Advantageous effects by the first embodiment will be described below.

(1) The steering column device1according to the first embodiment includes: the outer column7having a tubular shape and arranged along the vehicle longitudinal direction; the inner column9inserted in the outer column7in such a way as to be movable in the tube-axis direction and capable of telescopic operation; the restricting member11provided through the tubular wall21at the lower section of the outer column7in such a way as to be capable of coming in and out of the tubular wall21in the thickness direction thereof, and configured to restrict the front-end position of the inner column9in the direction of telescopic contraction thereof with the stopper part31; and the load absorbing wire13including the first ends45engageable with the restricting member11and the second end49supported on the inner column9side, and configured to be deformed by movement of the second end49toward the vehicle front side together with the inner column9upon application of a load of the preset value or greater to the inner column9toward the vehicle front side, to thereby absorb the load.

The stopper part31of the restricting member11is normally disposed to project to a radially inner side of the inner peripheral surface59of the tubular wall21of the outer column7, and the stopper parts31of the restricting member11are capable of being moved by the load absorbing wire13to a position on a radially outer side of the inner peripheral surface59of the tubular wall21of the outer column7when the load absorbing wire13is deformed upon application of a load of the preset value or greater to the inner column9toward the vehicle front side.

Thus, when the inner column9moves toward the vehicle front side in a collision of the vehicle, the stopper part31of the restricting member11sinks below (radially outer side of) the inner peripheral surface59of the tubular wall21of the outer column7. In this way, the front end of the inner column9can avoid contact with the stopper part31of the restricting member11and move toward the front side beyond the stopper part31. This makes it possible to suppress abrupt increase in impact absorption load in the middle of absorption of the impact energy.

(2) The restricting member11, with which the first ends45of the load absorbing wire13engage, includes the wire push surfaces26.

Thus, when the first ends45of the load absorbing wire13move toward the vehicle rear side upon application of a load of the preset value or greater to the inner column9toward the vehicle front side, the first ends45of the load absorbing wire13can push down the wire push surfaces26of the restricting member11. Hence, the restricting member11can be forcibly released from the wire holding part51of the outer column7. This makes it possible to further suppress abrupt increase in impact absorption load in the middle of absorption of the impact energy.

Second Embodiment

Next, a second embodiment will be described with reference toFIGS. 7 to 11C. The same components as those in the above-described first embodiment will be denoted by the same reference signs, and description thereof will be omitted.

A restricting member according to the second embodiment is such that the wire push surfaces of its lower holding part are formed as inclined surfaces.

As illustrated inFIGS. 7 to 10C, a restricting member111according to the second embodiment integrally includes a lower holding part23extending in the vehicle width direction, a linking part25extending upward from a center portion of the lower holding part23in the vehicle width direction, an upper holding part27linked to the lower holding part23by the linking part25, an upper extension part29provided on the upper holding part27, and a stopper part31formed at the front end of the upper extension part29. Further, the upper surfaces of the right and left sides of the lower holding part23are formed as wire push surfaces120which are inclined surfaces126extending obliquely upward toward the rear side relative to the tube-axis direction of the outer column7in a side view. The vehicle rear side of the stopper part31is formed as a contact surface33.

Next, movement of the restricting member111in a collision of the vehicle will be described with reference toFIGS. 11A to 11C.

As illustrated inFIG. 11A, during normal vehicle travel, the stopper part31of the restricting member111is disposed to project to a radially inner side (upper side inFIG. 11A) of the inner peripheral surface59of the tubular wall21of the outer column7. With triangular-prism protrusions37on the restricting member111biting into the wire holding part51at the lower section of the outer column7, the restricting member111is held in the wire holding part51and does not get released by its own weight. Also, the bent parts43(first ends45) of the load absorbing wire13are housed in the notches53of the wire holding part51.

As illustrated inFIG. 11B, when a load of the preset value or greater is applied to the inner column9toward the vehicle front side in a collision of the vehicle, the inner column9moves toward the front side together with the locking member68and the second end49of the load absorbing wire13. Then, the main parts41of the load absorbing wire13turn counterclockwise in the side view about the cam member57such that the bent parts43sink. At the same time, as the bent parts43of the load absorbing wire13exit the notches53of the wire holding part51and move toward the rear side, the bent parts43slide on the wire push surfaces120of the restricting member111while pushing down the wire push surfaces120. Note that the wire push surfaces120in the second embodiment are formed as the inclined surface126, which extend obliquely upward toward the rear side in the side view. Hence, when the bent parts43of the load absorbing wire13move toward the vehicle rear side, the restricting member111is moved downward to a greater extent than the first embodiment. Consequently, the restricting member111is released from the wire holding part51of the outer column7, as illustrated inFIGS. 11B and 11C.

An advantageous effect by the second embodiment will be described below.

The restricting member111, with which the first ends45of the load absorbing wire13engage, includes the inclined surfaces126, which extend obliquely upward toward the rear side relative to the tube-axis direction of the outer column7in a side view.

Thus, when the first ends45of the load absorbing wire13move toward the vehicle rear side upon application of a load of the preset value or greater to the inner column9toward the vehicle front side, the bent parts43(first ends45) of the load absorbing wire13push down the inclined surfaces126of the restricting member111. Accordingly, the bent parts43of the load absorbing wire13can push down the restricting member111to a greater extent.

Third Embodiment

Next, a third embodiment will be described with reference toFIGS. 12A to 12C. The same components as those in the above-described first and second embodiments will be denoted by the same reference signs, and description thereof will be omitted.

A load absorbing wire according to the third embodiment is such that its first ends45(front ends) are bent in a V shape in a side view.

Specifically, as illustrated inFIG. 12A, bent parts243formed in a V shape in a side view are provided at first ends45of a load absorbing wire13. More specifically, the front ends of the load absorbing wire13include main parts41extending straight in the side view and the bent parts243bent from the front ends of the main parts41in such a way as to extend obliquely downward toward the front side. Meanwhile, the third embodiment uses the same restricting member11as the first embodiment.

Next, movement of the restricting member11in a collision of the vehicle will be described with reference toFIGS. 12A to 12C.

As illustrated inFIG. 12A, during normal vehicle travel, the stopper part31of the restricting member11is disposed to project to a radially inner side (upper side inFIG. 12A) of the inner peripheral surface59of the tubular wall21of the outer column7. With the triangular-prism protrusions37of the restricting member11biting into the wire holding part51at the lower section of the outer column7, the restricting member11is held in the wire holding part51and does not get released by its own weight.

As illustrated inFIG. 12B, when a load of the preset value or greater is applied to the inner column9toward the vehicle front side in a collision of the vehicle, the inner column9moves toward the front side together with the locking member68and the second end of the load absorbing wire13. Then, the main parts41of the load absorbing wire13turn counterclockwise in the side view about the cam member57such that the bent parts243sink. At the same time, since the bent parts243of the load absorbing wire13are bent in the V shape in the side view, as the load absorbing wire13moves toward the rear side, the lower sides of the front ends of the bent parts243slide toward the rear side on the bottom surfaces of the wire insertion parts35of the restricting member11while pushing down the bottom surfaces of the wire insertion parts35. Consequently, the restricting member11is released from the wire holding part51of the outer column7, as illustrated inFIGS. 12B and 12C.

An advantageous effect by the third embodiment will be described below.

(1) The bent parts243formed in the V shape in a side view are provided at the first ends45of the load absorbing wire13.

Thus, when the first ends45of the load absorbing wire13move toward the vehicle rear side upon application of a load of the preset value or greater to the inner column9toward the vehicle front side, the bent parts243at the first ends45of the load absorbing wire13push down the restricting member11. Accordingly, the bent parts243at the first ends45of the load absorbing wire13can push down the restricting member11to a greater extent.

Fourth Embodiment

Next, a fourth embodiment will be described with reference toFIG. 13andFIGS. 14A to 14B. The same components as those in the above-described first to third embodiments will be denoted by the same reference signs, and description thereof will be omitted.

As illustrated inFIG. 13andFIGS. 14A to 14B, a restricting member311according to the fourth embodiment includes an upper part313movable in the vertical direction and a lower part315pivotally supported in such a way as to be capable of turning to push down the upper part313.

The upper part313includes a catching part317provided on the lower side, and a stopper part319provided on the catching part317. The stopper part319normally projects to a radially inner side (upper side inFIGS. 13 and 14) of the inner peripheral surface59of the tubular wall21of the outer column7. When projecting to the radially inner side of the tubular wall21, the stopper part319restricts the front-end position of the inner column9in the direction of telescopic contraction thereof. Also, the catching part317is configured to be pushed down by contacting the lower part315, as described later.

The lower part315is a member bent in an L-shape in a side view with a front leg part321extending toward the front side and a lower leg part323extending downward from the rear end of the front leg part321, and is pivotally supported at its middle part to the outer column7via a turn shaft portion325such that the lower part315can turn. Also, at the lower end of the lower leg part323, a wire hook portion327is formed which is recessed upward. The first ends45of the load absorbing wire13are inserted and caught in this wire hook portion327.

Next, movement of the restricting member311in a collision of the vehicle will be described with reference toFIGS. 14A to 14B.

As illustrated inFIG. 14A, during normal vehicle travel, the stopper part319projects to a radially inner side (upper side inFIGS. 14A to 14B) of the inner peripheral surface59of the tubular wall21of the outer column7.

When a load of the preset value or greater is applied to the inner column9toward the vehicle front side in a collision of the vehicle, the inner column9moves toward the front side together with the locking member68and the second end49of the load absorbing wire13. Then, the main parts41of the load absorbing wire13turn counterclockwise in the side view about the cam member57such that the front ends (first ends45) sink, and the load absorbing wire13moves rearward.

Since the front ends (first ends45) of the load absorbing wire13are caught in the wire hook portion327of the lower part315of the restricting member311, the lower part315turns counterclockwise about the turn shaft portion325with the rearward movement of the load absorbing wire13.

Consequently, as illustrated inFIG. 14B, the front leg part321of the lower part315pushes down the catching part317of the upper part313, so that the stopper part319moves to a radially outer side (lower side inFIG. 13andFIGS. 14A to 14B) of the inner peripheral surface59of the tubular wall21of the outer column7.

An advantageous effect by the fourth embodiment will be described below.

The restricting member311includes the upper part313provided at its upper end with the stopper part319configured to project to a radially inner side of the tubular wall21of the outer column7, and the lower part315configured to be turnable with the first ends45of the load absorbing wire13caught thereon.

When the first ends45of the load absorbing wire13move toward the vehicle rear side upon application of a load of the preset value or greater to the inner column9toward the vehicle front side, the lower part315turns about the turn shaft portion325to push down the upper part313. In this way, the first ends45of the load absorbing wire13can push down the stopper part319of the restricting member311to a greater extent.

It is to be noted that the present is not limited to the above-described embodiments but various changes and the like can be made thereto.