JPS624269B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a straight-line position holding device for a steering device in an automobile.

In automobiles, it is very desirable to be able to operate the steering wheel easily from the perspective of reducing fatigue of the driver, but on the other hand, if the steering wheel is operated lightly, it becomes unclear where the vehicle is going straight.
A problem arises in that it gives a sense of anxiety to the driver.

In order to deal with this problem, in a rack and pinion type steering device, a recess is provided in a part of the rack shaft, and a ball that fits into the recess in the straight-ahead position is supported by a spring on the gearbox, and the straight-ahead position is moderated. The present applicant has developed a device that holds the device with the same force (see Utility Model Application No. 131,975/1983).

However, it is mainly when driving at high speeds that the driver feels uneasy because the straight-ahead position is ambiguous, and if the pushing force of the ball by the spring is set to be optimal for driving at high speeds, the steering operation becomes too heavy when driving at low speeds. A problem arises.

The present invention aims to deal with such problems, and will be described below with reference to the accompanying drawings.

Fig. 1 shows a rack and pinion type steering device, in which 1 is a steering wheel, 2 is a steering shaft, 3 is a connecting shaft, and 4 is a pinion shaft with a pinion 5 attached to the tip. meshes with the rack shaft 6 in the gearbox 7 as shown in FIG.
When the steering wheel 1 is rotated, the pinion 5 is rotated via the steering shaft 2 and the connecting shaft 3, and the rack shaft 6 is moved in the axial direction, and the steered wheels (front wheels) are rotated via the tie rod or the like. ing.

A ball (such as a steel ball) 8 is assembled in the gearbox 7 in a state where it is pressed against the rack shaft 6 by a spring 9, and on the other hand, the ball 8 of the rack shaft 6 slides or rolls while being pressed. A substantially chevron-shaped groove 6a is formed in a part of the outer circumferential surface of the steering device, and the groove 6a is deep in the center and has a gentle slope that gradually becomes shallower toward both sides. The ball 8 is in the groove 6
It is set to be located at the deepest point of a.

The spring 9 is configured to be able to change the pressing force of the ball 8 according to the vehicle speed by an automatic spring force adjustment device 10 that is activated when the vehicle speed exceeds a set value.

In the present invention, the spring force automatic adjustment device 10 includes:
As shown in FIG. 3, it is characterized by a combination of an electromagnet 15 whose polarity changes depending on the vehicle speed, and a magnet 14 which is repelled or attracted by the change in polarity of the electromagnet.

That is, the spring case 9a is fitted into the gearbox 7 so as to be movable in a direction perpendicular to the axis of the rack shaft, a magnet 14 is fixed to the bottom of the spring case 9a, and an electromagnet is placed on the side of the gearbox 7 so as to face it. Installed on vehicle speed sensor 1
The configuration is such that the polarity of the electromagnet 15 is changed depending on the signal No. 3.

Assuming that the surface of the magnet 14 facing the electromagnet 15 is the north pole, when the vehicle speed is low, the upper surface of the electromagnet 15 is the south pole;
The spring case 9a is attracted to the lower position, and the pressing force of the spring 9 against the ball 8 is weakened.

When the vehicle speed exceeds a set vehicle speed of, for example, 80 km/h, the vehicle speed sensor 13 is activated to reverse the direction of energization to the electromagnet 15, and the polarity of the electromagnet 15 is reversed so that the top surface becomes the north pole.

Then, the magnet 14 repulses against the electromagnet 15, pushes up the spring case 9a, and the ball pressing force of the spring 9 becomes strong.

With this configuration, when traveling straight at high speed, the ball 8 is pressed against the concave groove 6a with a strong force by the spring 9 due to the repulsive force of the magnet 14 caused by the electromagnet 15, and this pressing force is applied to the ball 8 when the ball 8 is concave. It works to forcibly maintain the state of being fitted into the deepest part of the groove 6a, that is, the state of moving straight. In this case electromagnet 15
Since the repulsive force of the magnet 14 against the magnet 14 is inversely proportional to the square of the distance between the two, the rack shaft 6 is displaced from the straight position to either the left or right, and the ball 8 is pushed down by the left and right slopes of the groove 6a, causing the spring 9 to move downward. When the spring case 9a is pushed down by the spring reaction force, the repulsive force of the magnet 14 against the electromagnet 15 increases greatly, and the restoring force that tries to return the rack shaft 6 to the straight-ahead position becomes even stronger, making it difficult to go straight in a high-speed running state. The problem of vague location and anxiety for the driver can be completely eliminated.

When steering at high speeds, the easy shaft 6 moves in the axial direction while pushing down the ball 8 against the spring force of the spring 9. Generally, when driving at high speeds, the resistance between the tires and the road surface is small and the steering wheel is light. Therefore, as described above, as the steering wheel is turned, the repulsive force of the magnet 14 against the electromagnet 15 increases, and the pressing force of the ball 8 by the spring 9 increases. It can be gradually increased in size to improve steering stability and steering feel.

When driving at medium or low speeds, the polarity of the electromagnet 15 is reversed to attract the magnet 14 and the spring case 9a is held at the lowest position, so the ball pressing force by the spring 9 is extremely small or almost zero, and steering operation is difficult. This solves the problem of the weight becoming heavier.

As described above, according to the present invention, it is possible to completely eliminate the problem of unstable straight-line position of the steering device when driving at high speeds, and also solve the problem that the steering operation becomes too heavy when driving at medium to low speeds. This problem can be solved and can bring about great practical effects.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view of a rack and pinion type steering device to which the present invention is applied, Fig. 2 is a schematic cross-sectional explanatory view of the basic structure of the present invention, and Fig. 3 is a specific structural example of the present invention. It is a sectional view of the main part. 5...Pinion, 6...Rack shaft, 6a...Concave groove, 7...Gearbox, 8...Ball, 9...
Spring, 9a...Spring case, 10...
... Spring force automatic adjustment device, 13 ... Vehicle speed sensor, 1
4...Magnet, 15...Electromagnet.

Claims (1)

[Claims] 1. A roughly chevron-shaped groove is provided in a part of the rack shaft along the longitudinal direction of the rack shaft, with the central part being deepest and gradually becoming shallower toward both sides. The spring is supported in a rack and pinion type steering device in which the ball that fits in the deepest part is supported by a spring on the gearbox, and the straight-ahead position is maintained by the force of the spring pressing the ball against the groove. A spring case is fitted into the gearbox so as to be movable in a direction perpendicular to the axis of the rack shaft, a magnet is fixed to the bottom of the spring case, and an electromagnet whose polarity changes depending on the vehicle speed is attached to the magnet. When the vehicle speed is below the set value, the electromagnet attracts the magnet and moves the spring case away from the rack shaft, weakening the spring force of the spring. When the vehicle speed exceeds the set value, the electromagnet attracts the magnet. A linear position holding device for a steering device, characterized in that the polarity of the magnet changes and the magnet repulses to move the spring case closer to the rack shaft and strengthen the spring force of the spring.