JPH11278285A - Falling type steering column - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a falling type steering column which reduces manufacturing costs and the rate of the occurrence of defectives, etc. SOLUTION: A column bracket 21 formed as a press molding of a steel plate is secured to and integrated with the upper part of a steering column 1. The column bracket 21 comprises a U-cross-section base part 23 welded to the outer peripheral surface of the steering column 1 and a pair of right and left flange parts 25 bent from the upper end of the base part 23. The end of each flange part 25 extends along the axis of the steering column 1 and is set to be a relatively short distance away from the axis of the steering column 1. A pair of right and left capsules 31 formed as die-cast moldings of an aluminum alloy or as steel products are tightened to the lower surface of a vehicle body side member by bolts 33, and the flange parts 25 of the column bracket 21 are fitted into holding grooves 35 formed in the capsules 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drop-out type steering column, and more particularly to a technique for reducing a manufacturing cost and a defective product occurrence rate.

[0002]

2. Description of the Related Art When an automobile collides with another automobile, a building, or the like, the driver collides with the steering wheel due to inertia, which may cause serious damage to the head and chest.
In recent years, impact absorbing steering shafts and drop-off steering columns have been widely used in passenger cars and the like in order to prevent such a situation. The shock-absorbing steering shaft is such that the steering shaft on the steering wheel side collapses (shortens) when the driver makes a secondary collision. The steering shaft is divided into an outer shaft and an inner shaft, and both shafts are serrated. It is slidably connected. Usually, an impact energy absorbing mechanism is provided between the outer shaft and the inner shaft, which resists the collapse of the steering shaft, and when an axial load of a predetermined value or more acts, the steering shaft collapses. At this time, the impact energy is absorbed by the impact energy absorbing mechanism.

[0003] On the other hand, the drop-out type steering column is used to smoothly operate the shock absorbing type steering shaft.
When the driver makes a secondary collision, the steering column falls off together with the steering shaft. In the drop-off type steering column, a column bracket integrated with the steering column is fixed to a vehicle body-side member via a capsule, and a column bracket comes off from the capsule due to an impact load at the time of a secondary collision. Usually, a U-shaped notch with a rearward opening is formed on the left and right sides of the column bracket, and a parallel or V-shaped concave groove formed at the outer end of the capsule is formed on the inner surface of the notch. At the same time, a resin pin is fitted into a through hole formed in the column bracket and the capsule. Therefore, at the time of the secondary collision, after the resin pin is first broken, the notch slides and separates forward with respect to the concave groove, so that the column bracket (that is, the steering column) becomes a capsule (that is, the vehicle body side). Components).

[0004]

However, the conventional detachable steering column has problems that it is difficult to reduce the manufacturing cost due to its structure, and that the occurrence rate of defective products at the time of manufacturing increases. For example, the notch formed in the column bracket needs to be finished with high dimensional accuracy because the groove at the outer end of the capsule fits with a predetermined fitting margin, and the width is too large or too small. If it does, it must be discarded as a defective product. Also, the column bracket and the capsule have a plurality (usually four each)
After the through-holes are drilled at the same position, resin pins are injection-molded into these through-holes, which complicates the mold used for hole processing (press molding and die-cast molding), It is necessary to install an expensive injection molding machine. Furthermore, since the column bracket has a notch into which the capsule fits, the width of the column bracket becomes large, so that the support rigidity of the steering column is inevitably reduced.
Vibration and harshness). SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a drop-out type steering column which aims to reduce the manufacturing cost and the rate of defective products.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, there is provided a column bracket having a pair of left and right flange portions fixed to a steering column and extending in the left-right direction from the steering column. A detachable steering column, comprising: a pair of left and right capsules fixed to a member and having a holding groove on an inner surface thereof, into which a side end of the flange portion is fitted. In the present invention, the groove width of the holding groove is set to be slightly smaller than the thickness of the column bracket, and then the flange portion of the column bracket is press-fitted into the holding groove of the capsule. Let it be done with binding power.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a vehicle cabin side portion of a steering device, and reference numeral 1 in the figure denotes a steering column made of a steel pipe. The steering column 1 is fixed to the vehicle body side member 3 at two upper and lower positions, and rotatably supports the upper steering shaft 5 by a bearing (not shown). A steering wheel 7 is attached to an upper end of the upper steering shaft 5, and a lower steering shaft 11 is connected to a lower end of the upper steering shaft 5 via a universal joint 9. In the figure, 13
A column cover 15 covers an upper portion of the steering column 1, and 15 is a dashboard that partitions a vehicle compartment and an engine room.

In this steering device, when the driver rotates the steering wheel 7, the rotational force is transmitted to a steering gear (not shown) via the upper steering shaft 5 and the lower steering shaft 11. The steering gear has a built-in rack-and-pinion mechanism that converts a rotational input into a linear motion, and the steering is performed by changing the steering angle of the wheel via a tie rod or the like. Various types of steering gears such as a ball screw type and a worm roller type are known in addition to the rack and pinion type.

As shown in FIG. 2 (enlarged perspective view of the portion A in FIG. 1) and FIG. 3 (enlarged sectional view taken along the line BB in FIG. 1), the steering column 1 Column bracket 21 is fixedly and integrally formed. The column bracket 21 includes a base 23 having a U-shaped cross section welded to the outer peripheral surface of the steering column 1 and a base 2.
3. A pair of left and right flange portions 25 bent from the upper end of 3
It consists of In the case of the present embodiment, the flange 25
Is extended along the axis (column center) O of the steering column 1 and the distance L from the column center O is set relatively short. On the other hand, on the lower surface of the vehicle body side member 3, a pair of left and right capsules 31 of an aluminum alloy die-cast product or an iron product are fastened by bolts 33. Are fitted. In the drawing, reference numeral 37 denotes a bolt hole formed in the capsule 31, which is a long hole extending in the front-rear direction in order to facilitate adjustment when assembling to the vehicle body side member 3.

As shown in FIG. 4, the holding groove 35 of the capsule 31 is formed in a spindle shape in which the opening end 39 is narrowed, and the groove width W of the opening end 39 is equal to that of the flange 25 of the column bracket 21. It is set smaller than the thickness T. Thereby, when the flange portion 25 is fitted into the holding groove 35, the elastic portion of the material of the capsule 31 (such as an aluminum alloy or iron) and / or the plastic deformation of the capsule 31 and the flange portion 25 cause the flange portion 25 to move. 35, the pressure is held.

Next, the column bracket 21 and the capsule 3
1 will be described. In this embodiment, the assembling worker can slide the capsule 31 along the axial direction of the steering column 1 by using a simple device such as a hydraulic device, and thereby, the flange portion 2 of the column bracket 21.
5 is pressed into the holding groove 35. If the press-in resistance at that time is excessive, the assembling operator slides the capsule 31 a predetermined number of times to wear or plastically deform the holding groove 35 so that the press-in resistance falls within a specified value. By adopting such a method, the occurrence rate of defective products can be significantly reduced by appropriately setting the groove width W of the opening end 39. Even if the thickness control of the column bracket 21 and the dimensional control of the capsule 31 cannot be performed sufficiently, the press-fit resistance of the flange portion 25 into the holding groove 35 can be adjusted, so that stable performance can be obtained.

Hereinafter, the operation of the present embodiment will be described. When driving the vehicle, the driver grips the steering wheel 7 with both hands, so that a part of the driver's weight acts on the steering wheel 7 during turning or the like. Therefore, when the support rigidity of the steering column 1 is low, the steering wheel 7 swings, and the driver feels anxiety. However, in the case of this embodiment, the distance L from the column center O to the end of the flange 25 is relatively short, and
Since the capsule 31 is a high-rigidity aluminum die-cast product or an iron product, the support rigidity of the steering column 1 becomes extremely high, and such a problem hardly occurs, and the NVH of the steering system is reduced. Further, since the column bracket 21 is relatively small, material costs and press die costs are reduced, and the weight of the steering system is also reduced.

On the other hand, when the driver makes a secondary collision with the steering wheel 7 due to the collision of the vehicle, a large impact load acts on the steering column 1 via the upper steering shaft 5. Then, the column bracket 21
Escapes from the capsule 31 forward, and the steering column 1 falls off the vehicle body side member 3. At this time, most of the impact energy is absorbed by the impact-absorbing (collapsible) upper steering shaft 5 and the like, but a part of the impact energy is caused by friction resistance and plasticity when the flange portion 25 slides in the holding groove 35. It is also absorbed by deformation resistance, thereby improving the shock absorption characteristics of the steering system.

The description of the specific embodiment has been completed.
The aspects of the present invention are not limited to the above embodiment.
For example, as shown in FIG. 5, a notch 41 may be provided at the outer end of the capsule 31 instead of the bolt hole, and in this case, the weight of the capsule 31 can be further reduced. Further, in the above embodiment, the column bracket made of steel plate and the capsule made of aluminum alloy are used, but these may be both made of aluminum alloy, or the column bracket made of steel plate and cast iron or forged steel may be used. A capsule may be used, or a column bracket made of an aluminum alloy and a capsule made of cast iron or forged steel may be used. Further, a projection or a wavy portion may be formed on the sliding surface of the flange portion of the column bracket or the holding groove of the capsule. In this case, the impact energy absorption characteristics can be changed and improved. Further, the specific shapes of the holding bracket, the column bracket and the capsule, and the like can be appropriately changed without departing from the gist of the present invention.

For example, as a modified example of the column bracket 21, as shown in FIG. 6, there is a column bracket 21 in which a locking portion 51 is formed at a front portion of a flange portion 25. In this example, even if a force that pushes the steering column 1 rearward is applied at the time of the primary collision, the rear end of the locking portion 51 abuts and locks on the front end of the capsule 31, so that the steering column 1 pushes up. Is prevented. Further, as a modified example of the capsule 31, as shown in FIG.
(Not shown in FIG. 7). In this example, the distance l between the end of the flange portion 25 and the bolt 33 is
And the support rigidity of the steering column 1 is further improved.

Further, assuming that the concept of the present invention is applied to the above-mentioned conventional steering device, as shown in FIGS.
Parallel capsule 6 engaging with U-shaped groove 61 formed in
3 and a tapered groove 65 formed in the column bracket 21 as shown in FIGS. 10 and 11 (viewed in the direction of arrow D in FIG. 10).
There is a taper-shaped capsule 67 in which a holding groove 35 similar to the above embodiment is formed. In these examples,
The column bracket 21 and the capsule 6 are formed by the holding groove 35.
Since the coupling force with the third and the 67 can be appropriately set and the resin pin is not required, most of the problems in the conventional device are eliminated.

[0016]

As described above, according to the drop-off type steering column according to the present invention, the column bracket having a pair of right and left flange portions fixed to the steering column and extending in the left-right direction from the steering column is provided. A pair of left and right capsules, which are fixed to the vehicle body side member and have a holding groove on the inner surface thereof, into which the side end of the flange portion fits, is combined with the fact that an injection molding machine becomes unnecessary. In addition to significantly reducing the manufacturing cost and the defective product occurrence rate, it is possible to improve the support rigidity of the steering column, reduce the weight of the steering system, and reduce the NVH in the steering system.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a structure of a steering device on a passenger compartment side.

FIG. 2 is an enlarged perspective view of a portion A in FIG.

FIG. 3 is an enlarged sectional view taken along line BB in FIG.

FIG. 4 is a front view of the capsule.

FIG. 5 is a perspective view of a capsule partially changed in shape.

FIG. 6 is a perspective view of a main part of a steering device in which the shape of a column bracket is changed.

FIG. 7 is a longitudinal sectional view of a main part of a steering device in which the shape of a capsule is changed.

FIG. 8 is a plan view of a parallel capsule to which the concept of the present invention is applied.

FIG. 9 is a view as viewed in the direction of arrow C in FIG. 8;

FIG. 10 is a plan view of a tapered capsule to which the concept of the present invention is applied.

FIG. 11 is a view as viewed in the direction of arrow D in FIG. 10;

[Explanation of symbols]

 1 Steering column 3 Body side member 5 Steering shaft 7 Steering wheel 21 Column bracket 31 Capsule 25 Flange 35 Holding groove

Claims (1)

[Claims] 1. A column bracket fixed to a steering column and having a pair of left and right flange portions extending in the left-right direction from the steering column, and a holding portion fixed to a vehicle body-side member and having a side end of the flange portion fitted therein. A drop-off type steering column comprising a pair of left and right capsules having a groove on an inner surface thereof.