JP2008024170A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device with a simple constitution capable of certainly accomplishing desired impact absorption performance. <P>SOLUTION: In the steering device, a steering shaft 1 for transmitting operation of a steering wheel to a steering mechanism is supported at the inside of a cylindrical housing 2 provided with an inner cylinder 3 and an outer cylinder 4 internally/externally fitted over appropriate length, and impact energy of secondary collision applied to the steering shaft 1 through the steering wheel is absorbed by relative movement in a longitudinal direction generated under predetermined resistance between the inner cylinder 3 and the outer cylinder 4. An action piece 40 is projectedly provided on a lower end of the outer cylinder 4 in the longitudinal direction, and a part of a peripheral wall of the inner cylinder 3 is outwardly cut/stood. A corresponding pressing piece 30 is provided on an end of the action piece 40, and burst grooves 32, 32 extending in a longitudinal direction are provided on the peripheral wall of the inner cylinder 3 continuing to a lower side of the pressing piece 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a steering apparatus including energy absorbing means for absorbing impact energy of a secondary collision applied to a steering member during a vehicle collision.

  Many vehicle steering devices support a steering shaft that is rotatable about an axis inside a passenger compartment, and a steering wheel as a steering member is attached to an upper end portion of the steering shaft, while a lower end portion is provided outside the passenger compartment. The steering wheel is connected to the steering mechanism, and the rotation operation of the steering wheel by the driver in the passenger compartment is transmitted to the steering mechanism via the steering shaft. Is configured to perform steering by changing the direction of the left and right front wheels.

Such a steering device is designed to reduce the impact energy of the secondary collision for the purpose of reducing the damage applied to the driver colliding with the steering wheel (secondary collision) due to the inertial effect in the traveling direction at the frontal collision of the vehicle. It may be configured as a shock absorbing steering device that absorbs. The shock absorbing steering device includes an inner cylinder and an outer cylinder that are fitted inside and outside for a suitable length in the middle of a cylindrical housing that rotatably supports a steering shaft, and the fitting of the inner cylinder and the outer cylinder While the part moves relative to the axial length direction under a predetermined resistance, it is configured to absorb impact energy associated with the secondary collision (see, for example, Patent Document 1).
JP 2002-293249 A

  Now, in the steering device configured as described above, a driver colliding with the steering wheel is added with a reaction force due to the relative movement of the inner cylinder and the outer cylinder as a reaction force, thereby reducing the driver's damage. In order to achieve the initial purpose, it is important to move the inner cylinder and the outer cylinder relative to each other under a substantially constant resistance over the entire length of the sliding stroke.

  In the steering device described in Patent Document 1, the peripheral wall of the outer cylinder is caulked, and a plurality of protrusions protruding inward are provided on the inner peripheral surface of each position, and these protrusions are connected to the outer peripheral surface of the inner cylinder. It is comprised so that a movement resistance may be added in this press-contact part. However, in this configuration, since the magnitude of the resistance depends on the degree of pressure contact of the protrusions, there is a problem that a solid difference is likely to occur in the movement resistance and it is difficult to realize a desired shock absorbing performance.

  There has also been proposed a steering device in which a resistance member such as a ball or a ring is held between the inner cylinder and the outer cylinder, and movement resistance is applied via these resistance members. According to this configuration, it is possible to increase the accuracy of the movement resistance, but there is a problem that the number of parts increases and the man-hours for processing and assembly increase.

  The present invention has been made in view of such circumstances, and the inner cylinder and the outer cylinder constituting the support housing of the steering shaft are moved relative to each other under a substantially constant resistance, so that a desired shock absorbing performance is reliably realized. An object of the present invention is to provide a steering device having a simple configuration that can be achieved.

  A steering apparatus according to a first aspect of the present invention is an interior of a cylindrical housing having an inner cylinder and an outer cylinder that are fitted inside and outside a steering shaft that transmits an operation of a steering member to a steering mechanism. The impact energy of the secondary collision applied to the steering shaft via the steering member at the time of a vehicle collision is relatively moved in the axial direction between the inner cylinder and the outer cylinder under a predetermined resistance. In the steering device that absorbs by the above, the action piece projecting in the axial length direction at the fitting side end of the outer cylinder with the inner cylinder, and a part of the peripheral wall of the inner cylinder are cut and raised outward, A pressing piece provided with one side facing the end of the action piece, and a tear groove formed on the peripheral wall of the inner cylinder continuously to the other side of the pressing piece and extending in the axial length direction. And

  A steering device according to a second aspect of the present invention is formed by bending the tip of the action piece inward according to the first aspect inward, and inserted into an opening remaining in the peripheral wall of the inner cylinder by cutting and raising the pressing piece. It is characterized by providing.

  In the steering apparatus according to the first aspect of the present invention, the inner cylinder and the outer cylinder constituting the support housing for the steering shaft are provided in the outer cylinder when they move relative to each other in the axial length direction due to the impact force caused by the secondary collision. The action piece presses the pressing piece provided on the inner cylinder, tears the continuous tear groove on the other side of the pressing piece, and the inner cylinder and the outer cylinder move relative to each other in the axial direction against the tearing resistance. Thus, the impact energy of the secondary collision is absorbed, so that the desired shock absorbing performance can be realized with a simple configuration by managing the dimensions of the tear groove.

  In the steering device according to the second aspect of the invention, the bending portion provided by bending the tip of the action piece inward is inserted into the opening remaining after the pressing piece is cut and raised, so that the action piece that presses the pressing piece is the bending portion. Due to the guide action, the inner part of the inner part and the outer part of the inner cylinder and the outer cylinder are generated against the tearing resistance of the tear groove. The present invention has an excellent effect such that the relative movement can be performed stably and the desired shock absorbing performance can be realized with certainty.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof. FIG. 1 is a schematic diagram showing an overall configuration of a steering apparatus according to the present invention.

  In the figure, reference numeral 1 denotes a steering shaft, and the steering shaft 1 is rotatably supported coaxially inside a column housing 2 having a cylindrical shape. The column housing 2 is inclined with the upper bracket 20 fixed at the midway part and the lower bracket 21 fixed at one side end so that the lower bracket 21 side is directed forward and downward (lower left in the figure). It is supported inside the passenger compartment by its posture.

  A steering wheel 10 as a steering member is fitted and fixed to the upper end portion of the steering shaft 1 protruding above the column housing 2 so as to face the driver in the vehicle interior, and the steering shaft 1 also protrudes downward. The lower end is connected to the input shaft 14 of the steering mechanism 13 via an intermediate shaft 11 having universal joints 12 and 12 at both ends. With the above configuration, when the steering wheel 10 is rotated for steering, the rotation of the steering shaft 1 corresponding to this operation is transmitted to the steering mechanism 13 via the intermediate shaft 11 and the input shaft 14, Steering is executed by the operation of the steering mechanism 13.

  The steering apparatus shown in FIG. 1 includes a steering assist motor 22 attached in the vicinity of the lower end portion of the column housing 2, and the rotation of the motor 22 is transmitted to the steering shaft 1 inside the column housing 2 so as to be described above. The impact absorbing structure shown below, which is a feature of the present invention, directly transmits the rotation operation of the steering wheel 10 to the steering mechanism 13. Needless to say, the present invention can also be applied to a manual steering device that performs steering, and can also be applied to a hydraulic power steering device that assists steering by the generated force of a hydraulic cylinder attached to the steering mechanism 13.

  Inside the column housing 2, a torque sensor 23 for detecting a steering torque applied to the steering shaft 1 in response to the rotation operation of the steering wheel 10 is provided above the mounting portion of the motor 22. The motor 22 is configured to be driven based on torque detected by the torque sensor 23. As is widely implemented, this driving is performed to generate an auxiliary force that is obtained by correcting the reference auxiliary force determined by the torque detected by the torque sensor 23 based on the detection result of the running state such as the vehicle speed and the degree of turning. can do.

  The upper half of the column housing 2 that continues to the upper position of the torque sensor 23 includes an inner cylinder 3 and an outer cylinder 4 that are fitted inside and outside over an appropriate length and combined so as to be relatively movable in the axial direction. Yes. The upper bracket 20 is fixed to the middle part of the outer cylinder 4, and is connected to a part of the vehicle body via a capsule 24 and exceeds a predetermined limit applied downward to the column housing 2 via the steering wheel 10. It is configured as a well-known breakaway bracket that leaves the capsule 24 in the vehicle body and is separated downward by the action of force.

  FIG. 2 is an external perspective view of the fitting portion of the inner cylinder 3 and the outer cylinder 4. As shown in this figure, the inner cylinder 3 located on the lower side is cut down and raised in a rectangular shape with a part of the peripheral wall below the lower end edge of the outer cylinder 4 fitted to the outside, leaving a lower side. A plurality of push pieces 30, 30..., Which are raised in the direction, and rectangular openings 31, 31... Remaining as cut traces of the respective push pieces 30, 30. In the figure, the pressing pieces 30, 30 ... and the openings 31, 31 ... are equally arranged at four places in the circumferential direction (only two places are shown). , 31... Need only be provided at a plurality of locations in the circumferential direction, and are preferably provided in a uniform manner.

  Two such split grooves 32, 32 extending in the axial length direction are formed on the lower side of the push pieces 30, 30,. As shown in the figure, these tear grooves 32 and 32 are narrow linear grooves formed by drilling the outer surface of the peripheral wall to a predetermined depth, and have a lower strength than the other parts, respectively. It is provided so that the acting force on the pieces 30, 30 ... is concentrated.

  On the other hand, the outer cylinder 4 positioned on the upper side has the same number of action pieces 40 (only two are shown) as the pressing pieces 30, 30... 40 ... are evenly distributed. The illustrated action pieces 40, 40... Are narrow plates extending in the axial length direction with the base end fixed to the outer periphery of the lower peripheral edge of the outer cylinder 4. Bending portions 41, 41... Bent inward over an appropriate length are provided. .. Can be realized by welding, for example, and the action pieces 40, 40... Can be provided integrally with the outer cylinder 4.

  The inner cylinder 3 and the outer cylinder 4 configured in this manner are positioned and fitted so that the former push pieces 30, 30... And the latter action pieces 40, 40. The bent portions 41, 41 ... of the tips of 40, 40 ... are inserted into the openings 31, 31 ..., and the push pieces 30 provided on the inner cylinder 3 with the tips of the action pieces 40, 40 ... provided with the bent portions 41, 41 ..., As shown in FIG. 2, the column housing 2 is configured so as to face 30.

  FIG. 3 is an explanatory diagram of the shortening operation of the column housing 2 that occurs with the relative movement of the inner cylinder 3 and the outer cylinder 4. FIG. 3A shows a state at the time of assembly. As described above, the inner cylinder 3 and the outer cylinder 4 are fitted to the inner cylinder 3 from the respective end edges to the inner and outer sides over a predetermined length. The provided pressing piece 30 and the tip of the action piece 40 provided on the outer cylinder 4 are in a state of facing each other.

  FIGS. 3B and 3C show a state in which a force in the axial length direction is applied to the column housing 2 downward (force directed from the outer cylinder 4 toward the inner cylinder 3). At this time, the column housing 2 can be shortened telescopically by increasing the fitting length of the inner cylinder 3 and the outer cylinder 4, and by this shortening, the bent portion 42 at the tip of the action piece 40 provided on the outer cylinder 4. As shown in FIG. 3 (b), the inner cylinder 3 collides with the pressing piece 30, and the bending portion 42 is submerged inside the corresponding pressing piece 30, and the action piece 40 is deformed so as to be bent inward.

  At this time, as shown by the white arrow in FIG. 3B, the pushing piece 30 of the inner cylinder 3 receives a downward outward pushing force from the action piece 40, and this force is shown in FIG. Thus, it concentrates on the tear grooves 32 and 32 provided continuously below the pressing piece 30, and these tear grooves 32 and 32 begin to tear. Thereafter, as shown in FIG. 3C, the inner cylinder 3 and the outer cylinder 4 are separated from each other by a split groove 32 on the lower side of the pressing piece 30 by the action of a pressing force applied from the acting piece 40 to the pressing piece 30. The fitting length is increased so that the ripped portion sandwiched between 32 is peeled outward, and the shortening of the column housing 2 further proceeds.

  The shortening of the column housing 2 that progresses in this way occurs under resistance when the ripped portion sandwiched between the tearing grooves 32 and 32 is peeled off. Depends on dimensions (depth and width). As described above, the tear grooves 32 and 32 are continuous with the pushing piece 30 formed by cutting and raising the peripheral wall of the inner cylinder 3 outward. For example, the tearing grooves 32 and 32 are formed at the same time as the pushing piece 30 is cut and raised. According to the procedure, it is possible to provide the dimensions with high accuracy, and the column housing 2 can be shortened under a certain resistance.

  Further, since the pressing piece 30 is provided so as to rise outside the inner cylinder 3 and the action piece 40 provided on the outer cylinder 4 is opposed to the pressing piece 30, the acting force when the inner cylinder 3 and the outer cylinder 4 are shortened. Can be reliably transmitted to the pushing piece 30 and the split grooves 32, 32 continuous to the lower part thereof. Further, a plurality of push pieces 30 and action pieces 40 are provided in the circumferential direction of the inner cylinder 3 and the outer cylinder 4, and the above-described resistance is generated at each position. Therefore, the shortening of the column housing 2 occurs stably.

  The number of the push pieces 30 and the action pieces 40 arranged in parallel can be set as appropriate within the range of the circumferential lengths of the inner cylinder 3 and the outer cylinder 4, but excessive juxtaposition is the inner cylinder 3 and the outer cylinder. 4 is accompanied by a decrease in strength, so that it is appropriate to use 4 or less as shown in the embodiment. As described above, it is desirable that the push piece 30 and the action piece 40 are equally arranged in the circumferential direction, so that the resistance at the time of shortening is equalized in the circumferential direction, and the twist between the inner cylinder 3 and the outer cylinder 4 is prevented. Stable shortening can be realized without occurring.

  In the column housing 2 having the inner cylinder 3 and the outer cylinder 4 as described above, when the driver collides with the steering wheel 10 (secondary collision) due to the inertia of the front during the frontal collision of the vehicle, FIG. As indicated by the white arrow inside, a downward force in the axial direction is applied.

  At this time, as described above, the upper bracket 20 configured as a breakaway bracket is detached from the vehicle body, and the outer cylinder 4 released from the restraint by the upper bracket 20 is fitted to the inner cylinder 3 while increasing the length thereof. The relative movement causes the column housing 2 to be shortened. As described above, the shortening is performed by the action piece 40 of the outer cylinder 4 pressing the pushing piece 30 of the inner cylinder 3 and tearing the tearing grooves 32, 32 continuous to the lower part of the pushing piece 30. It occurs during a stroke (S in FIG. 1) corresponding to the extended length of 32, 32, and the impact energy of the secondary collision is absorbed during this shortening. During this time, the driver who has collided with the steering wheel 10 is only subjected to the resistance caused by the tearing of the tear grooves 32, 32 as a reaction force, and the driver is protected from the impact caused by the secondary collision without taking much damage. Is done.

It is a mimetic diagram showing the whole steering device composition concerning the present invention. It is an external fitting perspective view of the fitting part of an inner cylinder and an outer cylinder. It is explanatory drawing of the shortening operation | movement of the column housing which arises with the relative movement of an inner cylinder and an outer cylinder.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Steering shaft, 2 Housing, 3 Inner cylinder, 4 Outer cylinder, 10 Steering wheel (steering member), 13 Steering mechanism, Acting piece, 30 Pressing piece, 31 Opening, 32 Split groove, 40 Acting piece, 41 Bending part

Claims (2)

The steering shaft for transmitting the operation of the steering member to the steering mechanism is supported inside a cylindrical housing having an inner cylinder and an outer cylinder fitted inside and outside for an appropriate length, and the steering is performed in the event of a vehicle collision. In a steering device that absorbs impact energy of a secondary collision applied to the steering shaft via a member by a relative movement in the axial length direction generated under a predetermined resistance between the inner cylinder and the outer cylinder,
An action piece projecting in the axial direction at the fitting side end of the outer cylinder with the inner cylinder;
A part of the peripheral wall of the inner cylinder is cut and raised outward, and a pressing piece provided with one side facing the end of the working piece;
A steering device comprising: a tear groove formed on a peripheral wall of the inner cylinder continuously to the other side of the pressing piece and extending in the axial length direction.   The steering apparatus according to claim 1, further comprising a bent portion formed by bending a tip of the action piece inwardly and inserted into an opening remaining in a peripheral wall of the inner cylinder by cutting and raising the pressing piece.

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