JP2003327134A - Shock-absorbing type steering gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a locking device from interfering with an operation for an energy absorption mechanism, and to secure dimension control for each part and a sufficient length of compression stroke, so as to surely provide desired secondary energy absorption performance, in constitution provided with a column housing for absorbing secondary collision energy in compression of an inner cylinder and an outer cylinder fitted internally and externally, and the locking device restricting rotation of a column shaft. <P>SOLUTION: A holding hole 60 penetrated through the both cylinders 50, 51 is formed in an engaged part of the inner cylinder 50 and the outer cylinder 51 in the column housing 5. A holding cylinder 61 made of a resin material is fitted into the holding hole 60 astride the inner cylinder 50 and the outer cylinder 5, and a tip of a key cylinder 63 for the locking device 6 is fitted within a range of a thickness of the outer cylinder to be fixed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention absorbs energy of a secondary collision applied to a column shaft at the time of a vehicle collision by shortening the column shaft supporting the column shaft along with the column shaft in the axial direction. The present invention relates to a shock absorbing steering device having a structure.

[0002]

2. Description of the Related Art A vehicle is steered by operating a steering means such as a steering wheel arranged inside a vehicle compartment outside a vehicle compartment for steering a steering wheel (generally a front wheel). It is performed by telling the steering mechanism. A steering wheel as a steering means is attached to an upper end portion of a column shaft rotatably supported around an axis inside a vehicle compartment so as to be operated by a driver.

The column shaft is rotatably supported inside a cylindrical column housing, and is supported together with the column housing in a tilted posture with the mounting side of the steering wheel facing rearward and upward. The lower end of the column shaft projecting to the lower side of the column housing is connected to a steering mechanism arranged outside the vehicle compartment via an intermediate transmission shaft having universal joints at both ends. The steering mechanism includes a motion converting unit such as a rack and pinion, and the rotation of the steering wheel transmitted to the steering mechanism via the column shaft and the intermediate transmission shaft controls the operation of the wheel via the motion converting unit. Converted into movement for direction.

Most of the steering devices configured as described above have a secondary collision in order to reduce the damage to the driver who collides with the steering wheel (secondary collision) due to the action of inertia in the forward direction when the vehicle collides. It has an energy absorbing mechanism for absorbing the energy of. In general, this energy absorbing mechanism is provided with an expandable portion that can be expanded and contracted in the axial direction of the column shaft and the column housing with appropriate resistance in the middle part of the column shaft, and the expandable portion is shortened by the action force at the time of a secondary collision. It is configured to absorb the energy of the secondary collision by the sliding resistance during the pressing.

The expandable portion of the column shaft is formed by fitting a solid inner shaft and a hollow outer cylinder over an appropriate length and connecting them by a shear pin made of resin filled in the fitting portion. When the axial force exceeding the shearing allowable value of the shear pin acts due to the secondary collision described above, a known configuration is provided in which the inner shaft enters the inside of the outer cylinder and is shortened in the axial direction. The shear pin is necessary to enable rotation transmission from the outer cylinder to the inner shaft during normal steering, and the shear allowable value is set to be sufficiently larger than the shear force applied in the circumferential direction during normal steering. ing.

The contracting portion of the column housing is constructed by fitting the ends of an inner cylinder and an outer cylinder, both of which have a tubular shape, into the inside and outside over a suitable length. These mating parts include balls,
A resistance member, such as a protrusion, that generates sliding resistance accompanied by plastic deformation of the fitting peripheral surface is provided, and the inner cylinder and the outer cylinder are formed by the resistance member when the axial force due to the secondary collision is applied. It is designed to shrink in the axial direction under applied resistance.

On the other hand, in the steering device constructed as described above, for example, in order to prevent theft during parking, the steering device is operated in response to a predetermined lock operation such as turning off the ignition key to rotate the steering wheel. A lock device for restraining the lock is attached.

This locking device comprises a key cylinder fixed to the outside of the column housing, and a lock key built into this key cylinder and protruding inside the column housing in response to the locking operation. By engaging the tip of the key with an engaging portion provided at a corresponding position of the column shaft, the rotation of the column shaft in the column housing, that is, the rotation of the steering wheel is constrained.

[0009]

However, in the steering apparatus having the above-mentioned energy absorbing mechanism together with the above-mentioned lock device, the key cylinder fixed to the column housing has the inner cylinder and the outer cylinder generated for the energy absorption. There is a problem that the fixed position of the key cylinder is limited to a position outside the sliding stroke of the both cylinders so as not to prevent shortening, and a sufficient sliding stroke is secured by the presence of the locking device. However, there is a problem that it is difficult to obtain a desired energy absorption performance.

In order to solve this problem, Japanese Unexamined Patent Publication No. 8-198121 discloses a column housing having an inner cylinder or an outer cylinder provided with a notch at a circumferential position corresponding to a fixed portion of a key cylinder. When the inner cylinder and the outer cylinder for energy absorption are shortened, the key cylinder is received in the cutout portion,
A steering device is disclosed in which interference with shortening of an inner cylinder and an outer cylinder of a column housing is prevented.

However, in this structure, due to the presence of the cutout portion, the fitting portion between the inner cylinder and the outer cylinder, and
It is difficult to control the accuracy of the resistance member interposed in the fitting portion, and there is a possibility that desired energy absorption performance cannot be obtained.

The present invention has been made in view of such circumstances, and has an inner cylinder and an outer cylinder fitted inside and outside, and an energy absorption provided with a column housing that absorbs energy of a secondary collision by shortening these. In a configuration including both a mechanism and a lock device that restrains the rotation of the column shaft by a predetermined operation, interference of the lock device with the operation of the energy absorbing mechanism is prevented, dimensional control of each part and sufficient shortening of the length. An object of the present invention is to provide an impact absorption type steering device which can surely realize a desired secondary energy absorption performance by securing a stroke.

[0013]

According to a first aspect of the present invention, there is provided a shock absorbing steering system, wherein a steering device is provided inside a column housing having an inner cylinder and an outer cylinder fitted inside and outside by a fitting portion of an appropriate length. A column shaft that rotates according to the operation of the means is supported, and the energy of the secondary collision applied to the column shaft at the time of the collision of the vehicle is caused by the sliding of the inner cylinder and the outer cylinder generated under the resistance of the fitting portion. In a shock absorbing steering device that absorbs, a holding hole formed in the fitting portion of the inner cylinder and the outer cylinder by penetrating the peripheral walls of both cylinders in the thickness direction, and the thickness of the both cylinders in the holding hole. A holding cylinder fitted and held over a range, and fitted and fixed to the holding cylinder from the outside of the column housing within the thickness range of the outer cylinder, and protrudes into the column housing by a predetermined operation. Restrains the column shaft from rotating Characterized in that it comprises a key cylinder having a built-in lock key that.

In the present invention, the fitting portions of the inner cylinder and the outer cylinder are provided with the holding holes penetrating the both cylinders, and the holding cylinders are fitted and held in the holding holes over the thickness range of the inner cylinder and the outer cylinder. Then, the key cylinder of the lock device is fitted and fixed in the holding cylinder within the thickness range of the outer cylinder. When an axial force is applied to the column shaft due to the secondary collision, the holding cylinder is broken by the shearing force applied to the fitting portion of the inner cylinder and the outer cylinder by the action of this force, and the inner cylinder and the outer cylinder are fitted. While sliding under the resistance of the part, it contracts and absorbs the energy of the secondary collision. At this time, the key cylinder moves with the outer cylinder while maintaining the fixed state on the holding cylinder remaining on the outer cylinder side, and does not interfere with the contraction of the inner cylinder, and the desired energy absorption performance is realized.

A shock absorbing steering system according to a second aspect of the invention is characterized in that the holding cylinder in the first aspect is made of a resin material.

In the present invention, the holding cylinder for holding the key cylinder of the lock device is made of a resin material having stable strength characteristics, and the breaking of the holding cylinder due to the action of the axial force is caused with high accuracy, so that it is desirable. Achieve energy absorption performance.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the drawings showing the embodiments thereof. FIG. 1 is a vertical cross-sectional view showing a configuration of a main part of an impact absorption type steering device according to the present invention.

In the illustrated steering apparatus, a steering assisting motor M is attached to the outside of a housing H that rotatably supports a column shaft 1, and the rotation of the motor M is reduced inside the housing H by a speed reducer 2. Is transmitted to the column shaft 1 via a steering mechanism (not shown) connected to the lower end portion (the left end portion in the drawing) of the column shaft 1 via a universal joint U, and the steering mechanism operates to operate the steering mechanism. It is configured as a column-assist type electric power steering device that assists steering performed.

The column shaft 1 comprises an input shaft 11 and an output shaft 12 which are coaxially connected to each other via a torsion bar 10. The connecting portion between the two shafts 11 and 12 is not shown as steering means. Both axes 1 depending on the operation of the steering wheel
A known torque sensor 3 for detecting the steering torque applied to 1 and 12 is configured.

The lower half of the housing H is provided with a gear chamber 20 for accommodating the speed reducer 2 by enlarging the corresponding portion of the output shaft 12 constituting the column shaft 1 to a large diameter. The motor M is attached to the outer peripheral portion of the gear chamber 20 so as to have an axis substantially orthogonal to the output shaft 12. Speed reducer 2
Is provided with a worm 21 connected to the output shaft of the motor M protruding inside the housing H, and a worm wheel 22 fitted in the middle of the output shaft 12,
A worm gear reduction device in which the worm 21 is meshed with worm teeth formed on the outer periphery of 22.

In the steering device constructed as described above, the steering assisting motor M includes the torque sensor 3
Drive control is performed according to an operation command given from a control unit (not shown) based on the detection result of the steering torque.
The rotation of the motor M is reduced by the speed reducer 2 including the worm 21 and the worm wheel 22, and the output shaft 12
Is further transmitted to the steering mechanism via the universal joint U, and the steering performed by the operation of the steering mechanism is assisted.

Upper end of input shaft 11 (right end in the figure)
Is connected to a steering wheel (not shown) via a collapsible shaft 4 that constitutes an upper part of the column shaft 1. The collapsible shaft 4 includes a solid lower shaft 40 connected to the upper end of the input shaft 11 and a hollow upper cylinder 41 fitted over the upper end of the lower shaft 40 over an appropriate length. The shear pins 42 and 42 made of resin filled in the fitting portion are connected to each other, and the axial force of the shear pins 42 and 42 exceeding the allowable shearing force causes the lower shaft 40 to enter the upper cylinder 41. Along with this, there is provided a known configuration in which the energy of a secondary collision in which the driver collides with the steering wheel at the time of a vehicle collision is absorbed by the shortening.

The shear strength of the shear pins 42, 42 is set to be sufficiently larger than the shear force applied when transmitting the rotation from the upper cylinder 41 to the lower shaft 40 in response to the rotating operation of the steering wheel for steering. The steering torque applied to the steering wheel by the driver is surely transmitted to the input shaft 11 and the output shaft 12 via the collapsible shaft 4. The steering torque is detected by the torque sensor 3, and the steering assist motor M is executed as described above based on the torque detected by the torque sensor 3.
Proper steering assistance is provided by the drive control of.

In the drive control of the motor M, it is possible to realize an assist force characteristic suitable for the traveling state by making a correction based on the detection result of the traveling state such as the vehicle speed, the steering angle, the yaw rate. Many inventions have been made for this correction method, and an appropriate method may be selected from them.

Collapsible shaft 4 constructed as described above
Are supported inside a cylindrical column housing 5 that is connected to the upper end of the housing H. The column housing 5 is formed by fitting an inner cylinder 50 in the lower half part and an outer cylinder 51 in the upper half part over an appropriate length, and when the axial force acts, the fitting part slides. It has a publicly known structure that is shortened in the axial direction and absorbs energy of a secondary collision in which a driver collides with a steering wheel at the time of a vehicle collision.

FIG. 2 is an enlarged sectional view of the vicinity of the fitting portion between the inner cylinder 50 and the outer cylinder 51 of the column housing 5. As shown in this figure, a large number of balls 53, 53 held by a retainer 52 are interposed as resistance members in the fitting portion between the inner cylinder 50 and the outer cylinder 51, and the column housing 5 is shortened. The ball 53,
The plastic deformation of the fitting peripheral surfaces of the inner cylinder 50 and the outer cylinder 51 that come into contact with 53 ... Is generated as resistance.

The resistance member is not limited to the retainer 52 and the balls 53, 53, ..., but a large number of protrusions are provided on the fitting portion of the inner cylinder 50 and the outer cylinder 51 so as to project from one side and contact the other side. Alternatively, a suitable structure conventionally proposed such as a ridge or a resin sleeve press-fitted into the fitting portion can be adopted, and further, the inner cylinder 50 and the outer cylinder 51.
It is also possible to realize the fitting by press-fitting and directly provide the sliding resistance of the press-fitting portion.

The column housing 5 constructed in this way
Inside, the collapsible shaft 4 including the lower shaft 40 and the upper cylinder 41 is coaxially supported. In the steering device according to the present invention, the fitting portions of the inner cylinder 50 and the outer cylinder 51 of the column housing 5 are located above the fitting portions of the lower shaft 40 and the upper cylinder 41 of the collapsible shaft 4, that is, the upper cylinder. The column shaft 1 is located outside the middle portion of 41, and the operation for restraining the column shaft 1 to be non-rotatable in accordance with a predetermined operation is provided substantially at the center in the axial direction of the fitting portions of the inner cylinder 50 and the outer cylinder 51. An eggplant lock device 6 is attached.

The inner cylinder is attached to the mounting portion of the lock device 6.
A holding hole 60 penetrating the peripheral wall of the outer cylinder 51 and the outer cylinder 51 in the thickness direction is formed, and a holding cylinder 61 made of a resin material is fitted and fixed in the holding hole 60 over the thickness range of the both cylinders 50 and 51. Is provided. The lock device 6 is provided with a key cylinder 63 having a lock key 62 built-in. The fitting portion at the tip of the key cylinder 63 is fitted into the outer opening of the holding cylinder 61 so as to be substantially perpendicular to the outer surface of the outer cylinder 51. It is attached so as to stand up. Here, the holding cylinder 61 on the tip side of the key cylinder 63
The fitting length into the outer cylinder 51 is set so as to be within the thickness range of the outer cylinder 51 as shown in the drawing.

The key cylinder 63 attached in this way
The lock key 62 built in the key protrudes from the tip end side of the key cylinder 63 in response to a predetermined operation such as an off operation of the ignition key. Further, an engaging hole 43 capable of receiving the lock key 62 is formed in the peripheral wall of the upper cylinder 41 of the collapsible shaft 4 facing the inside of the mounting portion of the key cylinder 63, and is indicated by a chain double-dashed line in FIG. The tip end of the lock key 62 protruding as shown by is inserted into and engaged with the engagement hole 43, and by this engagement, the upper cylinder 41 inside the column housing 5 is engaged.
The rotation of the column shaft 1 including the upper cylinder 41 is non-rotatably restricted.

It should be noted that the lock key 62 is operated by turning on an ignition key for starting the engine before starting the traveling, as shown by a broken line in FIG.
Since it retreats into the inside of 63 and the engagement with the engagement hole 43 is released, the steering according to the operation of the steering wheel as described above becomes possible.

In the steering apparatus according to the present invention configured as described above, the operation of absorbing the energy of the secondary collision described above is performed as follows. The secondary collision is a phenomenon in which a driver moving forward due to inertia collides with a steering wheel due to a collision of a vehicle, and the collision causes the collapsible shaft 4 and a column housing 5 supporting the collapsible shaft 4.
A shock force in the axial direction is applied to.

The impact force applied to the collapsible shaft 4 is the lower shaft.
The shearable shaft 4 acts on the shear pins 42, 42 connecting the 40 and the upper cylinder 41, and the collapsible shaft 4 contracts in the axial direction by the impact force exceeding the shear allowable value of the shear pins 42, 42.

On the other hand, the impact force applied to the column housing 5 is due to the fitting of the inner cylinder 50 and the outer cylinder 51 constituting the column housing 5 with both cylinders.
It acts to cause sliding of 50 and 51. In the steering device according to the present invention, a holding hole 60 penetrating both the inner cylinder 50 and the outer cylinder 51 is formed in the fitting portion of the inner cylinder 50 and the outer cylinder 51, and the lock device 6 is attached to the holding hole 60. The holding cylinder 61 made of a resin material provided in the above is fitted and fixed over the thickness range of both the cylinders 50 and 51, and the sliding of the inner cylinder 50 and the outer cylinder 51 by the action of the impact force is The holding cylinder 61 is started with shear failure, and the inner cylinder 50 and the outer cylinder 51 thereafter slide under the resistance described above due to the action of being interposed in the fitting portion, and the column housing 5 is moved. Shorten.

FIG. 3 is an explanatory view of the shortening operation of the collapsible shaft 4 and the column housing 5 as described above. As shown in the figure, the contraction of the collapsible shaft 4 and the column housing 5 is caused by shearing of the shear pins 42, 42 on the fitting peripheral surface of the lower shaft 40 and the upper cylinder 41 of the collapsible shaft 4 and the inner cylinder 50 and the outer cylinder of the column housing 5. The holding cylinder 61 is in a sheared state on the fitting peripheral surface of 51, and the energy of the secondary collision is absorbed by the shortening of the collapsible shaft 4 and the column housing 5 which occurs in this state.

Here, the lock device 6 is attached to the holding cylinder 61.
The key cylinder 63 is fixed by fitting, but this fitting is realized within the range that does not exceed the thickness of the outer cylinder 51 as described above.
Even after the shear fracture of 61, it stops on the circumference of the outer cylinder 51 and moves together with the outer cylinder 51 as indicated by the white arrow in the figure, and does not hinder the sliding with the inner cylinder 50.

Therefore, the above-described energy absorbing operation is performed without interfering with the lock device 6, and the inner cylinder 50 and the outer cylinder are
By controlling the dimensions of the ball 51 and the balls 53, 53 as the resistance member, it is possible to accurately achieve a desired energy absorption performance. Further, the sliding stroke between the inner cylinder 50 and the outer cylinder 51 can be secured over the entire length range of the column housing 5 without being bothered by the existence of the lock device 6, and the collapsible shaft at this stroke can be secured. 4 and the column housing 5 can be shortened with a small resistance, and the burden on the driver during the above-described energy absorbing operation can be significantly reduced.

FIG. 4 is an enlarged cross-sectional view of the vicinity of the fitting portion of the collapsible shaft 4 and the column housing 5 showing another embodiment of the shock absorbing steering system according to the present invention.

The collapsible shaft 4 shown in the figure is the input shaft 11
The solid lower shaft 40 is connected to the upper end of the lower shaft 40, and the hollow upper cylinder 41 is fitted to the upper end of the lower shaft 40 over a suitable length and is serrated. The upper cylinder 41 and the lower shaft 40 are integrally formed by engaging a caulking portion 45 formed by caulking the corresponding portion of the former peripheral wall inwardly with a concave caulking groove 44 formed around the outer periphery of the latter. When the axial force exceeds a predetermined magnitude, the caulking portion 45 is plastically deformed, and the lower shaft 40 is allowed to enter the inside of the upper cylinder 41 while being shortened in the axial direction. is there.

Further, the rotation transmission from the upper cylinder 41 to the lower shaft 40 in response to the rotating operation of the steering wheel is performed by the action of serration in the fitting portion of both, and the steering torque applied to the steering wheel by the driver is collapsible. It is surely transmitted to the input shaft 11 and the output shaft 12 via the shaft 4.

The column housing 5 supporting the collapsible shaft 4 thus constructed is formed by fitting the lower half inner cylinder 50 and the upper half outer cylinder 51 over an appropriate length, and When the force is applied, the fitting portion is directly slid and shortened in the axial direction.

The fitting portion of the inner cylinder 50 and the outer cylinder 51 of the column housing 5 is located outside the middle portion of the upper cylinder 41 of the collapsible shaft 4 supported inside, as in the embodiment shown in FIG. A holding hole 60 that penetrates the peripheral walls of the inner cylinder 50 and the outer cylinder 51 in the thickness direction is formed substantially at the center of the fitting portion.
A holding cylinder 61 made of a resin material is fitted and fixed in the holding hole 60 over the thickness range of the both tubes 50, 51. The lock device 6 is provided with a key cylinder 63 having a lock key 62 built-in. The tip end of the key cylinder 63 is fitted into the holding cylinder 61 within the thickness range of the outer cylinder 51 to form an outer surface of the outer cylinder 51. It is attached so that it stands up at a right angle to.

The locking device 6 attached in this way
In response to a predetermined operation such as turning off the ignition key, as shown by a two-dot chain line in FIG.
A lock key 62 projecting from the tip side of 63 is engaged with an engagement hole 43 formed at a corresponding position on the peripheral wall of the upper cylinder 41 of the collapsible shaft 4 to prevent the column shaft 1 including the upper cylinder 41 from rotating. Make a restraining action. Further, the lock key 62 is retracted into the key cylinder 63 as indicated by a broken line in FIG. 4 by turning on an ignition key for starting the engine before starting traveling, whereby the column shaft 1 is restrained. Is released, steering can be performed according to the operation of the steering wheel as described above.

In the steering system as described above, when the above-mentioned secondary collision occurs, the collapsible shaft 4
Also, an impact force in the axial direction is applied to the column housing 5.
The impact force applied to the column housing 5 is the inner cylinder 50 and the outer cylinder.
A holding cylinder 61 fitted in a holding hole 60 penetrating the fitting portion of 51.
Concentrate on the inner cylinder 50 and the sound cylinder by shearing and breaking the holding cylinder 61.
51 and 51 start sliding, and the column housing 5 contracts.
As the sliding starts, the collapsible shaft 4 has an upper cylinder.
The caulking portion 45 provided on the 41 is plastically deformed so as to ride over the caulking groove 44 provided on the lower shaft 40, and the upper cylinder 41 and the lower shaft 40 slide and collapsible under the action of resistance caused by this deformation. The axis 4 contracts.

FIG. 5 is an explanatory view of the contracting and shortening operation of the collapsible shaft 4 and the column housing 5 shown in FIG. As shown in the figure, the reduction is caused by the holding cylinder 61 shearing on the fitting peripheral surfaces of the inner cylinder 50 and the outer cylinder 51 of the column housing 5, and the caulking portion 45 provided on the upper cylinder 41 of the collapsible shaft 4 corresponds to this. It occurs in a state of being plastically deformed together with the peripheral surface of the lower shaft 40 in contact with it, and the deformation resistance at this time absorbs the energy of the secondary collision.

Here, the key cylinder 63 of the lock device 6 is fitted and fixed to the holding cylinder 61, but this fitting is done within the range not exceeding the thickness of the outer cylinder 51 as described above. Therefore, the key cylinder 63 stops on the circumference of the outer cylinder 51 even after the shear fracture of the holding cylinder 61, and moves together with the outer cylinder 51 as shown by the white arrow in the drawing to Does not hinder the sliding between.

Therefore, the above-mentioned energy absorbing operation is performed without interfering with the lock device 6, and the fitting portion between the inner cylinder 50 and the outer cylinder 51 in the column housing 5 and the resistance member on the collapsible shaft 4 side. Caulking groove 44 that acts as
By controlling the size of the caulking portion 45, it is possible to achieve a desired energy absorption performance with high accuracy. Also, the inner cylinder 50
The sliding stroke between the outer cylinder 51 and the outer cylinder 51 can be secured over the entire length range of the column housing 5 without being bothered by the existence of the lock device 6, and the collapsible shaft 4 and the column housing within this stroke can be secured. 5 can be shortened with a small resistance, and the burden on the driver during the energy absorbing operation described above can be significantly reduced.

In the above embodiment, an example of application to an electric power steering apparatus having a motor for steering assistance has been described. However, the present invention is applied to a hydraulic power steering apparatus having a hydraulic actuator for steering assistance. It is needless to say that the present invention can be applied to a steering device for manual steering that does not include a steering assist means, and the same effect can be obtained.

[0049]

As described above in detail, in the shock absorbing steering system according to the present invention, the column housing can be shortened and shortened without interfering with the locking device for steering lock attached to the column housing. The present invention has excellent effects such that desired secondary energy absorption performance can be surely obtained by dimensional control of each part and ensuring a sufficient shortening stroke.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a configuration of a main part of an impact absorption type steering device according to the present invention.

FIG. 2 is an enlarged cross-sectional view in the vicinity of a fitting portion between an inner cylinder and an outer cylinder of a column housing.

FIG. 3 is an explanatory view of a contracting operation of the collapsible shaft and the column housing shown in FIG.

FIG. 4 is an enlarged cross-sectional view of a collapsible shaft and a vicinity of a fitting portion of a column housing showing another embodiment of the shock absorbing steering device according to the present invention.

FIG. 5 is an explanatory view of a contracting operation of the collapsible shaft and the column housing shown in FIG.

[Explanation of symbols]

1 column axis 4 Collapsible shaft 5 column housing 6 Lock device 40 Lower shaft 41 Upper cylinder 50 inner cylinder 51 outer cylinder 53 balls 60 holding hole 61 Holding tube 62 lock key 63 key cylinder H housing M motor

Claims (2)

[Claims] 1. A column shaft, which rotates in response to an operation of a steering means, is supported inside a column housing having an inner cylinder and an outer cylinder fitted inside and outside by a fitting portion of an appropriate length, and when the vehicle collides, In a shock absorbing steering device that absorbs energy of a secondary collision applied to a column shaft by sliding of the inner cylinder and the outer cylinder generated under resistance of the fitting portion, the fitting portion of the inner cylinder and the outer cylinder. A holding hole formed by penetrating the peripheral walls of both cylinders in the thickness direction, a holding cylinder fitted and held in the holding hole over the thickness range of the both cylinders, and the column having the holding cylinder. A key cylinder that is fitted and fixed from the outside of the housing within the thickness range of the outer cylinder and that projects into the column housing by a predetermined operation and locks the column shaft so that it cannot rotate. Impact characterized by Absorption type steering device. 2. The shock absorbing steering device according to claim 1, wherein the holding cylinder is made of a resin material.