JPH0516063Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) This invention relates to a steering device for an automobile that absorbs impact during a collision and protects the driver.

(Prior art) Conventionally, the above-mentioned device has a
There are some that are shown in the publication.

That is, the above-mentioned publication discloses a steering shaft, a steering handle is attached to the upper end of the steering shaft, and a steering wheel is connected to the lower end side of the steering shaft.

Further, the above-mentioned steering shaft is divided into an upper and lower part in the axial direction, and is composed of an upper shaft and a lower shaft, and the divided ends of the upper and lower shafts (corresponding to numerals 31 and 32 in the above publication) They are slidably fitted only in the axial direction. Further, the two divided ends are connected by a shear pin (corresponding to the symbol R in the above publication) so as to restrict this sliding movement.

According to the above configuration, for example, when a car collides while driving and the impact force at this time is transmitted from the lower shaft toward the upper shaft side, if this impact force is larger than a predetermined value, The shear pin shears, the divided end of the lower shaft slides relative to the divided end of the upper shaft, and the impact force is absorbed. This prevents the impact force from being transmitted to the upper shaft side, thereby protecting the driver who operates the steering wheel.

(Problems to be Solved by the Invention) By the way, in the conventional configuration described above, while the vehicle is running, the impact force that the steering wheel receives from the road surface is transmitted from the lower shaft side to the upper shaft side via the shear pin. becomes.

Therefore, since the shear pin is repeatedly subjected to the impact force, the shear pin is easily fatigued, and there is a possibility that the shear pin may be unexpectedly sheared.

(Purpose of the invention) This invention was made with attention to the above-mentioned circumstances, and the steering shaft is divided into an upper shaft and a lower shaft, and the divided ends of the upper and lower shafts are connected to each other with a shear pin. It is an object of the present invention to suppress fatigue of the shear pin due to the impact of driving an automobile, and to achieve this with a simple configuration.

(Structure of the device) The feature of this device to achieve the above object is that a part of the outer circumferential surface of the lower shaft is plastically deformed to form a protrusion, and the lower shaft supports the lower shaft. The protrusion is brought into contact with a portion of the lower bearing so as to restrict relative upward sliding of the lower shaft.

(Example) Hereinafter, an example of this invention will be described with reference to the drawings.

In the figure, reference numeral 1 denotes a steering device for an automobile, and this steering device 1 has a column tube 4 screwed to the stationary side 2 of the vehicle body with bolt bodies 3, 3.
have.

A steering shaft 5 is inserted into the column tube 4 on the axis of the column tube 4. The steering shaft 5 is supported by the column tube 4 through an upper bearing 6 and a lower bearing 7 so as to be rotatable about the axis of the steering shaft 5. Both the upper bearing 6 and the lower bearing 7 are radial ball bearings, each outer race of which is fixed to the column tube 4.

A steering handle 9 is attached to the upper end of the steering shaft 5, and a front wheel, which is a steering wheel, is connected to the lower end via a steering gear device (not shown).

Both the column tube 4 and the steering shaft 5 are vertically divided between an upper bearing 6 and a lower bearing 7, and the divided ends of the column tube 4 are fitted together so as to be slidable in the axial direction.

Further, the steering shaft 5 is divided as described above and is composed of an upper shaft 10 and a lower shaft 11. 6 so that it cannot slide vertically.

Therefore, the external force when operating the steering handle 9 is supported by the stationary side 2 of the vehicle body via the upper bearing 6 and column tube 4. On the other hand, the lower shaft 11 is supported by a snap ring 13 fitted onto the lower shaft 11 so that it cannot slide downwardly relative to the lower bearing 7.

The lower divided end 10a of the upper shaft 10 is a cylindrical body, and the upper divided end 11a of the lower shaft 11 is fitted into the divided end 10a by a spline so as to be slidable only in the axial direction.

A pair of resin shear pins 15, 15 are provided which radially penetrate through the fitting portions of the two divided ends 10a, 11a. The shear pins 15, 15 function as follows.

That is, when a car collides while driving, the impact force transmitted to the lower shaft 11 is transmitted to the shear pin 1.
5 and 15 to the upper shaft 10. At this time, if the strength of the impact force is greater than a predetermined value, the shear pins 15, 15 are sheared, as shown by the arrow A and the two-dot chain line in FIG. , slides upward within the split end 10a of the upper shaft 10,
The above impact force is absorbed. Therefore, this impact force is prevented from being transmitted to the upper shaft 10.

In the above-mentioned configuration, as shown in Fig. 1, a part of the outer peripheral surface of the lower shaft 11 is pressurized in the direction shown by the arrow B in the figure and plastically deformed, thereby forming a protrusion 16. This protrusion 16 is brought into contact with the lower surface of the inner race 7a of the lower bearing 7, and this protrusion 16 restricts the lower shaft 11 from moving upward relative to the lower bearing 7.

Therefore, various relatively small impact forces transmitted from the road surface to the lower shaft 11 while the automobile is running are supported by the stationary side 2 of the vehicle body via the projection 16, the lower bearing 7, and the column tube 4. Therefore, the relatively small impact force mentioned above is applied to the shear pin 1.
5, 15 is suppressed, that is,
Fatigue of the shear pins 15, 15 due to the above impact force is suppressed.

In the above state, when a large impact force is transmitted to the lower shaft 11, such as when a car collides, the protrusions 16, 16 are pressed against the lower surface of the inner race 7a of the lower bearing 7, causing deformation. The upper and lower shafts 11 can be slid upwardly relative to the upper and lower bearings 7. Then, for the first time, the shear pins 15, 15 perform the above-mentioned function. That is, if the impact force transmitted to the lower shaft 11 is greater than a predetermined value, the shear pins 15, 15 are sheared, and this impact force is prevented from being transmitted to the upper shaft 10.

Note that the projections 16 may be formed at a plurality of locations in the circumferential direction of the lower shaft 11, or may extend all around the circumference.

(Effect of the invention) According to this invention, a part of the outer peripheral surface of the lower shaft constituting the steering shaft is plastically deformed to form a protrusion, and the lower shaft is moved relative to the lower bearing that supports the lower shaft. Since the protrusion is brought into contact with a part of the lower shaft so as to prevent it from sliding upward, various relatively small impact forces transmitted from the road surface to the lower shaft while the vehicle is running are prevented. It is supported on the stationary side of the vehicle via the protrusion and the lower bearing. Therefore, this impact force is prevented from being transmitted to the shear pin connecting the divided ends of the upper shaft and the lower shaft.

Therefore, fatigue of the shear pin due to a relatively small impact force during traveling is suppressed, and the occurrence of the inconvenience of the shear pin being accidentally sheared is prevented.

Furthermore, the suppression of shear pin fatigue as described above was achieved simply by plastically deforming a portion of the outer circumferential surface of the lower shaft, and therefore no separate parts or special jigs were required. Therefore, the fatigue of the shear pin can be suppressed with a simple structure.

[Brief explanation of drawings]

The drawings show an embodiment of this invention, in which FIG. 1 is a partially enlarged view of FIG. 2, FIG. 2 is a side sectional view of the steering device, and FIG. 3 is a sectional view taken along the - line in FIG. 2. 1...Steering device, 2...Stationary side of the vehicle body,
5...Steering shaft, 6...Upper bearing,
7... Lower bearing, 10... Upper shaft, 10a
...Split end, 11...Lower shaft, 11a...
Split end, 15...shear pin, 16...protrusion.

Claims (1)

[Scope of utility model registration request] The steering shaft is supported on the stationary side of the vehicle by a pair of upper and lower bearings, and the steering shaft is divided into upper and lower parts between the upper and lower bearings, and consists of an upper shaft and a lower shaft. In a steering device in which the divided ends are slidably fitted only in the axial direction and the two divided ends are connected by a shear pin to restrict this sliding, a part of the outer circumferential surface of the lower shaft is made of plastic. A projection is formed by deformation, and the projection is brought into contact with a part of the lower bearing so as to restrict upward sliding of the lower shaft relative to the lower bearing. Steering device.