JPS6410390B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an impact energy absorbing steering device for an automobile, and more specifically, the invention relates to an impact energy absorbing steering device for an automobile, and more specifically, an impact energy absorbing steering device that absorbs impact energy through relative sliding motion between a shaft body and a tubular body that constitute a steering column. This invention relates to a steering device.

As shown in Japanese Utility Model Publication No. 53-13148, this type of impact energy absorbing steering device has a tapered portion on one member of a pair of fitting members that are slidable relative to each other in the axial direction. A structure is known in which an expandable ring is inserted into the narrow diameter portion of the tapered part, and the end of the other member is brought into contact with the ring.

According to this structure, when an impact force is applied in the axial direction of the steering column, the pair of fitting members slide while pushing the open ring apart.
Impact energy is thereby absorbed.

However, in the above structure, since the outer periphery of the open ring is not restrained at all, the diameter of the open ring expands without restriction in accordance with the sliding displacement of the fitting members. Therefore, the ring-opening itself requires extremely high mechanical strength, and the diameter of the ring-opening and the diameter of the ring-opening strands have to be increased, which poses a problem in that the overall size of the device increases.

The present invention was made in view of the above-mentioned conventional problems, and its purpose is to efficiently absorb impact energy with greater sliding resistance without increasing the size of the device. An object of the present invention is to provide an impact energy absorbing steering device.

The present invention provides an impact energy system in which a shaft body and a tubular body constituting a steering column are fitted together so that they can slide relative to each other in the axial direction, and impact energy is absorbed by the sliding movement of these shaft bodies and the tubular body. In an absorption type steering device, a first tapered part is formed in a part of the shaft body, and a second tapered part is formed in the end of the tube body adjacent to the first tapered part, so that the first and second tapered parts The second tapered portion forms an annular groove portion having a wedge-shaped cross section, and a stopper ring located within the annular groove portion and capable of expanding its diameter is attached to the small diameter portion of the first tapered portion.

According to this structure, the diameter of the stopper ring expands due to the taper action of the first tapered part when the shaft body and the pipe body slide, but the outer circumference of the stopper ring is connected to the second tapered part. Since the diameter is restrained by , free diameter expansion is restricted. This means that a force is generated that tries to reduce the diameter of the stopper ring and draw it toward the small diameter side of the annular groove, in opposition to the expansion of the diameter of the stopper ring.
Impact energy is absorbed with greater sliding resistance.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment of a steering device according to the present invention. This steering device is composed of a jacket tube 1 and a shaft body, that is, a steering shaft 2, to which a steering wheel (not shown) is attached. The tube 1 is fixed to the vehicle body 4 by an upper bracket 3, and the steering shaft 2 is also supported by bearings on the vehicle body 4 via a lower bracket 5 and a holder 6 which is a tube body. Note that 7 in the figure is a universal joint for connecting the steering shaft 2 to a steering gear (not shown).

The upper bracket 3 has a substantially U-shape as shown in FIG. It is integrally fixed to the upper bracket 3 by molding resin. Then, a mounting bolt 23 is inserted into the elongated hole 12 of the slide block 10.
By inserting the steering shaft 2
A jacket tube 1 including a jacket tube 1 is fixedly supported on a vehicle body 4. Here, when an impact force A due to a secondary collision is applied from the steering wheel side and a load exceeding a set value is applied to the molded resin, the resin is sheared and the slide block 10 is left on the vehicle body 4 side and the upper part is removed. The bracket 3 moves axially with the jacket tube 1, thereby absorbing impact energy.

As shown in FIGS. 1 and 4, the holder 6 is integrally fixed to the lower bracket 5 by bolts (not shown), and the steering shaft 2 is rotated through a bearing 13 made of a low friction coefficient resin inside. and is slidably supported. One end of the holder 6 is caulked so as to expand outward, thereby forming a second tapered portion 14.

On the other hand, in a part of the steering shaft 2 near the holder 6, a first
A tapered portion 15 is formed, and an annular groove portion 16 having a wedge-shaped cross section is formed by the first tapered portion 15 on the steering shaft 2 side and the first tapered portion 14 on the holder side. A stop ring 17 is attached to the minimum diameter portion of the first tapered portion 15 on the steering shaft 2 side with a slight step as shown in FIGS. 3 and 4. As shown in FIG. 3, this stopper ring 17 has an abutment at one location on its circumference so that its diameter can be expanded, and is sandwiched between both tapered parts 14 and 15 of the annular groove part 16. It is located in

In the steering device configured in this manner, when an impact force is applied to the steering shaft 2 from the direction P in FIG. 1 due to a collision, the slide block 10 shown in FIG. 2 is sheared and the initial impact energy is reduced. At the same time, the steering shaft 2 and the holder 6 undergo a relative sliding movement in the axial direction. At this time, both the first tapered portion 1
Although the stopper ring 17 attempts to slide while being pushed apart by the stopper ring 1, the stopper ring 1
7 has its outer periphery restrained by the second tapered portion 14, so that free diameter expansion is restricted. In other words, a force is generated which attempts to reduce the diameter of the stopper ring 17 and draw it toward the small diameter portion within the annular groove 16 in opposition to the diameter expansion of the stopper ring 17.
As the sliding displacement between the steering shaft 2 and the holder 6 increases, the sliding resistance between the first tapered part 15 and the stopper ring 17 and the second
The sliding resistance between the tapered part 14 and the stopper ring 17 increases, and as a result, the impact energy acting on the steering column is absorbed by the sliding resistance between the annular groove part 16 and the stopper ring 17. be done.

FIG. 5 shows another embodiment of the steering device according to the present invention. In this embodiment, the steering shaft 2 is divided into two, an upper shaft 2a and a lower shaft 2b, and an annular groove 16 is provided between the two. An energy absorbing portion is provided with a stopper ring 10. In the figure, the steering shaft 2 is divided into two parts, an upper shaft 2a and a lower shaft 2b, and is configured to be relatively slidable in a serration section 20. Similarly to the embodiment described above, a first tapered part 15 having a width l is provided in a part of the upper shaft 2a which is a shaft body, and a second taper part 15 is provided in an end part of the lower shaft 2b which is a tubular body. Part 14
are formed, respectively, and a stopper ring 17 is mounted so as to be located within an annular groove 16 formed by these first and second tapered portions 14 and 15. 8 is a bearing made of low friction coefficient resin.

Therefore, due to the collision, the upper shaft 2
When the lower shaft 2b and the lower shaft 2b slide, impact energy is absorbed by the sliding resistance between the annular groove 16 and the stopper ring 17, as in the first embodiment.

FIG. 6 shows still another embodiment of the steering device according to the present invention. In this embodiment, the steering shaft 2 is divided into an upper shaft 22a and a lower shaft 22b, as in the second embodiment. After dividing, lower shaft 22
b and the jacket tube 1, there is an annular groove 2
6 and a stopper ring 17 are provided. That is, in FIG. 6, a second tapered portion 14 is formed at one end of the jacket tube 1 as a tubular body by a collar 21 that is separate from the jacket tube 1.
A first tapered portion 25 having a width of l is formed on the lower shaft 22b as a shaft body, and a stopper is positioned within an annular groove portion 26 formed by these first and second tapered portions 14 and 25. ring 1
7 is installed.

Therefore, in this embodiment, when the jacket tube 1 and the lower shaft 22b slide, the impact energy is absorbed by the sliding resistance between the annular groove 26 and the stopper ring 17. .

In addition, by combining the second embodiment and the third embodiment, the sliding parts between the upper shafts 2a, 22a and the lower shafts 2b, 22b, and between the jacket tube 1 and the lower shafts 2b, 22b are There are annular grooves 16 and 2 at two places on the sliding part of the
6 and the stopper ring 17 can be expected to further improve the impact energy absorption efficiency.

As is clear from the above description, in the impact energy absorbing steering device according to the present invention, the sliding portion between the shaft and the tube has a first tapered portion on the shaft and a second taper on the tube. An annular groove portion having a wedge-shaped cross section is formed, and
The shaft body is equipped with a stopper ring that can expand in diameter and is located within an annular groove, and the shock is generated by the sliding resistance generated between the annular groove and the stopper ring against the expansion of the diameter of the stopper ring. Since it is constructed to absorb energy, it has greater sliding resistance and can efficiently absorb impact energy, and the stopper ring itself can be extremely small, simplifying the structure. Furthermore, since it can be implemented without making any major improvements to the original structure of the steering device, it is suitable for reducing the size and weight of the steering device, and at the same time has the effect of providing an inexpensive steering device as a whole.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional explanatory diagram showing an embodiment of the impact energy absorbing steering device according to the present invention;
Figure 2 is an exploded view showing details of the upper bracket shown in Figure 1, Figure 3 is an exploded view of the holder shown in Figure 1, Figure 4 is a sectional view of the holder, and Figures 5 and 6 are FIG. 7 is an explanatory cross-sectional view showing another embodiment of the present invention. 1... Jacket tube (tube), 2... Steering shaft (shaft), 2a... Upper shaft (shaft), 2b... Lower shaft (tube), 6... Holder (tube), 14... Second tapered part, 15, 25... First tapered part, 16,
26... Annular groove part, 17... Stopper ring,
22b...Lower shaft (shaft body).

Claims (1)

[Claims] 1. An impact energy absorbing steering system in which a shaft and a tubular body that constitute a steering column are fitted together so that they can slide relative to each other in the axial direction, and impact energy is absorbed by the sliding movement of these shafts and tubular bodies. In the apparatus, a first tapered part is formed in a part of the shaft, a second tapered part is formed in the end of the tube close to the first tapered part, and these first,
The second tapered portion forms an annular groove having a wedge-shaped cross section, and the small diameter portion of the first tapered portion is equipped with an expandable stop ring located within the annular groove. Absorption type steering device.