JP2006290207A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device capable of stably realizing desired energy absorption performance by utilizing a column shaft not affected by mounting of a support unit and an inner cylinder of a column housing for imparting resistance for absorption of impact energy. <P>SOLUTION: In the constitution having a column housing 3 having an outer cylinder 4 and an inner cylinder 5 slidably fitted in an axial direction and a cylinder part 14 and an inner shaft part rotated together and slidably fitted in the axial direction and provided with a column shaft 8 rotatably supported in the column housing 3, when the column shaft 8 is contracted in the axial direction by generation of secondary collision and a key ring 20 intrudes into the inner cylinder 5, predetermined slide resistance is generated between the key ring 20 and the inner cylinder 5 and the impact energy of secondary collision can be absorbed thereby. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a steering device, and more specifically, when a vehicle has a frontal collision and a driver collides with a steering wheel (hereinafter referred to as a secondary collision) due to an inertial action in the traveling direction of the vehicle. The present invention relates to a steering apparatus configured to absorb impact energy applied to a driver via a wheel.

  In many cases, an impact-absorbing steering device that absorbs the impact energy of a secondary collision includes a column housing that supports a column shaft, which is composed of an inner cylinder and an outer cylinder that are fitted inside and outside over an appropriate length. The cylinder and the outer cylinder are subjected to an energy absorbing action by reducing the length of the cylinder and the outer cylinder so as to increase the fitting length under a predetermined resistance by the action of an impact applied during the secondary collision. Various proposals have heretofore been made by changing the means for applying resistance between them (see, for example, Patent Documents 1 and 2).

The steering device disclosed in Patent Document 1 is caulked with the peripheral surface of the outer cylinder facing the inner cylinder and pressed against the inner cylinder, and when the impact of the secondary collision is applied, the caulked portion and the inner cylinder The impact energy is absorbed between the surface and the sliding resistance caused by these deformations. Further, the steering device disclosed in Patent Document 2 holds a friction member having a large frictional resistance in a fitting portion between the inner cylinder and the outer cylinder, and when the impact of the secondary collision is applied, the inner cylinder and the outer cylinder The configuration is such that impact energy is absorbed by frictional resistance generated between the friction member and the friction member.
JP 2004-9837 A JP 2000-219139 A

  However, since a support (bracket) for mounting to the vehicle body is fixed to the outer cylinder of the column housing by welding, the outer cylinder may be deformed by heat input during the welding, and this deformation may occur. In such a case, the pressure contact load between the caulking portion and the inner cylinder, or the negative pressure load between the friction member, the outer cylinder and the inner cylinder may be out of the design value, and the impact energy may not be absorbed as intended. was there.

  Also, in some steering devices, an impact absorber is interposed between the column housing support and the vehicle body, so that when a secondary collision impact is applied, the vehicle body and the support tool that is detached from the vehicle body. There is a configuration in which impact energy is absorbed by the deformation resistance of the shock absorber material ripped in between. According to this configuration, it is possible to eliminate the instability of the impact energy due to the deformation of the outer cylinder, but on the other hand, in order to cause the shock absorber to perform a predetermined deformation, the vehicle body side also has a certain accuracy. There is a problem that it is required and cannot be handled by the accuracy control of the steering device alone.

  The present invention has been made in view of such circumstances, and a desired energy absorption performance is obtained by utilizing the column shaft and the inner cylinder of the column housing, which are not affected by the attachment of the support, for providing resistance for absorbing impact energy. An object of the present invention is to provide a steering device capable of stably realizing the above.

  A steering device according to a first aspect of the present invention is capable of co-rotating with a column housing having an outer cylinder and an inner cylinder fitted to the outer cylinder so as to be slidable in the axial length direction. A steering device having a cylindrical portion and an inner shaft portion that are slidably fitted to each other and having a column shaft that is rotatably supported by the column housing, and facing the outer tube of the column portion of the column shaft When the large diameter portion is provided in the inner cylinder of the column housing, a predetermined sliding resistance is generated between the inner cylinder and the large diameter portion. It is configured.

  The steering device according to the second invention is characterized in that the large-diameter portion in the first invention is a key ring provided in the cylindrical portion.

  Further, in the steering device according to the third aspect of the invention, the key ring according to the second aspect of the present invention is configured separately from the cylindrical portion, and the cylindrical portion is allowed to pass through a slip ring that allows relative rotation by the action of a torque greater than a set value. It is fitted in.

  According to the first invention, when the impact of the secondary collision is applied to the column shaft, the column shaft is shortened so as to increase the fitting length between the tube portion and the inner shaft portion, and the large diameter portion provided in the tube portion. Is inserted into the inner cylinder of the column housing, and the impact energy is absorbed by the sliding resistance between the inner cylinder and the large diameter part. The impact energy absorption performance as designed can be stably realized.

  According to the second aspect of the invention, the key ring provided in the cylinder portion of the column shaft is used as the large diameter portion that generates the sliding resistance for absorbing energy with the inner cylinder of the column housing. No special parts are required, and the configuration can be simplified, the weight can be reduced, and the cost can be reduced.

  Further, according to the third invention, since the key ring is separated from the column shaft, the material size of the column shaft is not constrained by the outer diameter of the key ring necessary for managing the sliding resistance. The cost can be reduced, the outer diameter of the key ring can be controlled with high accuracy, and the desired impact energy absorption performance can be stably realized. In addition, the slip between the key ring and the cylinder portion can be achieved. Since a ring (trade name: tolerance ring) is interposed, the stable frictional resistance between this sliding ring and the key ring and the cylinder part is also useful for absorbing impact energy, and more stable energy absorption can be performed. Furthermore, even if the degree of freedom of setting the outer diameter of the key ring is further increased, the present invention has an excellent effect that it is possible to satisfy the insurance requirement standard for theft prevention required for the key ring.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof. FIG. 1 is a simplified longitudinal sectional view showing a main part of a steering apparatus according to the present invention. A column housing 3 is attached to a vehicle body (not shown) such that the axial length direction is inclined downward.

  The column housing 3 includes an outer cylinder 4 and an inner cylinder 5 fitted to the outer cylinder 4 so as to be slidable in the axial direction. The outer cylinder 4 is attached to the vehicle body via a known breakaway bracket (not shown) configured to be detached from the vehicle body when a predetermined axial force in the axial direction is applied. The magnitude of the force in the axial direction is set so as to protect the driver from the collision when the outer cylinder 4 is detached from the vehicle body when a secondary collision occurs. The lower part of the inner cylinder 5 is fixedly supported on the vehicle body via a support.

  A column shaft 8 is supported inside the column housing 3 so as to be rotatable on the same axis. The upper part of the column shaft 8 protrudes above the outer cylinder 4 via a bearing 9 that supports the same side, and a steering wheel 11 is attached to the upper end. The lower portion of the column shaft 8 is connected to a steering mechanism (not shown) via a power transmission mechanism.

  The column shaft 8 supported in this manner has a cylindrical portion 14 positioned on the inner side of the outer cylinder 4 and an inner shaft positioned on the inner side of the inner cylinder 5 so as to be fitted to the lower portion of the cylindrical portion 14 over an appropriate length. Part 15. The cylindrical portion 14 and the inner shaft portion 15 are configured such that a through-hole 16 formed in a uniform manner on the peripheral wall of the cylindrical portion 14 and an annular groove 17 provided around the outer peripheral surface of the inner shaft portion 15 These are positioned so as to be aligned at these two locations, and are connected so as to be able to rotate together by shear pins 18 formed by filling the resin material into the annular groove 17 through the respective through holes 16 and solidifying them. The shear pin 18 is dimensioned so as to cause a shear failure when a force greater than an allowable value is applied in the axial direction of the column shaft 8, and the column shaft 8 in which the failure has occurred has a cylindrical portion 14 and an inner shaft portion. 15 and can be shortened so as to increase the fitting length. The allowable breaking value of the shear pin 18 is set based on the upper limit allowable value of the impact force applied to the driver colliding with the steering wheel 11 at the time of the secondary collision.

  In the steering device according to the present invention, a cylindrical key ring 20 that is separate from the cylindrical portion 14 is fitted and fixed in the middle of the cylindrical portion 14 of the column shaft 8. An annular recess 21 is formed in the inner peripheral portion of the key ring 20, and the key ring 20 fitted on the cylindrical portion 14 is inserted into the annular recess 21, and the inner periphery of the annular recess 21 and the cylindrical portion 14 are inserted. It is fixed under the action of the frictional force of the sliding ring 22 that elastically contacts the outer periphery of the ring.

  FIG. 2 is an external perspective view of the sliding ring 22. As shown in the figure, the sliding ring 22 (commercialized as a tolerance ring) is a ring-shaped member having a slit-like missing portion at one place in the circumferential direction. The elastic protrusions 23 (four in the figure) are provided so as to project outward in the radial direction. The sliding ring 22 configured as described above is elastically contacted with the annular recess 21 and the cylindrical portion 14 by the elastic action of the elastic protrusion 23, and the cylinder is located under the sliding ring 22. The key ring 20 that is externally fitted to the portion 14 does not rotate relative to the tube portion 14 as long as a rotational torque less than the set value is applied, and even in a state where a torque greater than the set value is applied. Can rotate relative to each other under a large resistance.

  On the outer periphery of the key ring 20 attached in this way, key grooves 25 are formed at a plurality of locations in the circumferential direction. A through hole 26 is formed in the outer cylinder 4 of the column housing 3 so as to face the formation position of the key groove 25, and a casing 28 of a lock device 27 is attached to the through hole 26. The casing 28 is provided with a lock key 29 that protrudes inward when the ignition key is turned off. The tip of the lock key 29 that protrudes into the outer cylinder 4 through the through hole 26 is indicated by a two-dot chain line in the figure. As shown, the keyway 25 is configured to be engaged.

  When the lock key 29 is thus engaged, the rotation of the key ring 20 is restrained by the column housing 3, and the rotation of the column shaft 3 including the cylinder portion 14 to which the key ring 20 is attached is under resistance by the slip ring 22. As a result, the vehicle is restrained and cannot be steered by operating the steering wheel 11, and theft of the vehicle due to malicious intent can be prevented.

  When a large rotational force is applied to the steering wheel 11, the column shaft 3 can be rotated with the sliding of the sliding ring 22 with respect to the cylindrical part 14. Therefore, steering by operating the steering wheel 11 is virtually impossible, and the vehicle can be prevented from being stolen while preventing the key ring 20 from being damaged. It will be possible to meet the insurance requirements standards for.

In the steering apparatus according to the present invention, the outer diameter D ₁ of the key ring 20 as described above is set to be slightly larger than the inner diameter D ₂ of the inner cylinder 5 of the column housing 3 that is positioned at an appropriate distance below. ing. As a result, an axial force is applied to the column shaft 8 due to the occurrence of a secondary collision associated with the frontal collision of the vehicle, and the column shaft 8 is connected to the cylindrical portion 14 and the inner shaft portion due to shear failure of the shear pin 18 as described above. 15, the key ring 20 that moves downward together with the cylindrical portion 14 is fitted inside the inner cylinder 5 to generate a predetermined sliding resistance between them. The impact energy of the secondary collision is absorbed by the dynamic resistance.

  FIG. 3 is an explanatory diagram of the energy absorbing operation by the steering device according to the present invention. When the impact force accompanying the secondary collision is applied to the steering wheel 11 as shown by white arrows in the figure, the cylindrical portion 14 of the column shaft 8 is fitted to the inner shaft portion 15 to increase the length. Thus, the key ring 20 provided in the middle of the cylindrical portion 14 is fitted into the end portion of the inner cylinder 5 of the column housing 3 facing downward as shown in FIG.

  Here, since the outer diameter of the key ring 20 is larger than the inner diameter of the inner cylinder 5, the fitting of the key ring 20 occurs with a slight diameter expansion deformation of the inner cylinder 5, and the sliding resistance of both fitting parts is caused. The impact energy is absorbed by the contraction of the column shaft 8 that occurs under this resistance. This energy absorption occurs between the large diameter portion (key ring 20) provided in the middle of the column shaft 8 and the inner cylinder 5 of the column housing 3, and is caused by welding and fixing the breakaway bracket for supporting the vehicle body. Since the outer cylinder 4 that may change in dimensions is not involved, stable energy absorption performance can be obtained.

  The key ring 20 is a member configured separately from the column shaft 8, and can be dimensioned with high accuracy by independent molding and processing, and generates a desired sliding resistance with the inner cylinder 5. This makes it possible to stably realize the impact energy absorption performance as designed.

  Further, when the column shaft 8 is further contracted and the fitting length of the key ring 20 is increased, the slip ring 22 is also slipped between the key ring 20 and the cylindrical portion 14, and the slip ring 3 is moved downward from the annular recess 21 as shown in FIG. 3B, the sliding resistance at the fitting portion between the key ring 20 and the inner cylinder 5, the key ring 20, the cylindrical portion 14 and the sliding ring. Energy is absorbed by a synergistic effect with the sliding resistance between the two.

  Thus, the sliding resistance of the sliding ring 22 interposed between the key ring 20 and the cylindrical portion 14 also contributes to the absorption of impact energy. Here, as described above, the slip ring 22 that has been commercialized as a tolerance ring can generate a substantially constant slip resistance with high accuracy, and thus can perform more stable energy absorption.

  When the column shaft 8 contracts while absorbing energy as described above, the steering wheel 11 fixed to the upper end of the column shaft 8 abuts on the upper end of the outer cylinder 4 of the column housing 3 as shown in FIG. Thereafter, a downward axial force is also applied to the outer cylinder 4, and the column housing 3 is also shortened so as to increase the fitting length with the inner cylinder 5 fitted in the lower position. The sliding resistance between the outer cylinder 4 and the inner cylinder 5 also contributes to absorption of impact energy.

  As described above, the sliding resistance between the outer cylinder 4 and the inner cylinder 5 becomes unstable due to the involvement of the outer cylinder 4 whose size control is difficult, but this sliding resistance is the end of the shortening stroke for energy absorption. Because it occurs only in the vicinity. The influence on the driver colliding with the steering wheel 11 can be suppressed to a slight level.

It is a simplified longitudinal cross-sectional view which shows the principal part of the steering apparatus which concerns on this invention. It is an external appearance perspective view of a sliding ring. It is explanatory drawing of the energy absorption operation | movement by the steering device which concerns on this invention.

Explanation of symbols

3 Column housing 4 Outer cylinder 5 Inner cylinder 8 Column shaft 11 Steering wheel 14 Tube portion 15 Inner shaft portion 20 Key ring (large diameter portion)

Claims (3)

  A column housing having an outer cylinder and an inner cylinder fitted to the outer cylinder so as to be slidable in the axial length direction, and a cylindrical portion capable of rotating together and slidable in the axial length direction; In a steering apparatus having an inner shaft portion and a column shaft rotatably supported by the column housing, a large-diameter portion is provided in a portion of the column portion of the column shaft facing the outer tube, A steering apparatus, wherein when the large diameter portion is fitted into an inner cylinder of the column housing, a predetermined sliding resistance is generated between the inner cylinder and the large diameter section.   The steering apparatus according to claim 1, wherein the large-diameter portion is a key ring provided in the cylindrical portion.   The steering device according to claim 2, wherein the key ring is configured separately from the cylindrical portion, and is fitted into the cylindrical portion via a sliding ring that allows relative rotation by the action of torque equal to or greater than a set value.

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