JPH1151607A - Steering angle detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the compact and inexpensive steering angle detector which eliminates the need for a component for detection by detecting variation in the quantity of rotation of a clock spring for electric connection from variation in inductive reactance. SOLUTION: This device is equipped with the clock spring 1 constituted by connecting a rotor 3 which rotates as a steering wheel rotates and an external case 2 fixed on a steering column side by an FFC(flexible flat cable) 4. Then a conductor 6 for steering angle detection is built in the FFC 4 and variation in inductive reactance with the number of turns of the FFC 4 is detected through the conductor 6 to detect the steering angle of the steering wheel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering angle detecting device for detecting a steering angle of a steering wheel of a vehicle, and more particularly, to a clock spring having a flexible flat cable built in a connection between a steering wheel and a steering column. The present invention relates to a rudder angle detecting device using the same.

[0002]

2. Description of the Related Art FIGS. 8 and 9 show an example of a conventional steering angle detecting device (see Japanese Patent Application Laid-Open No. 5-254446). This steering angle detecting device includes a disc-shaped sensor board 9 on the outer periphery of a cylindrical portion 8 inserted through a steering shaft of a vehicle.
Is arranged. This sensor board 9 is attached to a transmission body 10 which rotates together with the steering wheel. The slit 11 provided on the sensor board 9
Is detected by the light receiving / emitting element in the detection unit 12,
The rotation of the steering shaft is detected, whereby the steering angle of the steering wheel is detected.

[0003]

In the above-mentioned conventional apparatus, the rotation of the sensor board 9 is detected by the detection unit 12, so that the sensor board 9 and the detection unit 1 for detection are detected.
2 is required, and there is a problem that the steering angle detecting mechanism is complicated, large, and costly.

The present invention has been made in view of the above points, and detects a change in the amount of rotation of a clock spring for electrical connection based on a change in inductive reactance, thereby eliminating the need for a component for detection. An object is to provide an inexpensive steering angle detection device.

[0005]

According to a first aspect of the present invention, a rotator rotating with the rotation of a steering wheel and an outer case fixed to a steering column are wound. A clock spring connected by a flexible flat cable, the flexible flat cable is formed by incorporating a conductor for steering angle detection, and a change in inductive reactance caused by a change in the number of turns of the flexible flat cable is detected by the conductor. The steering angle of the steering wheel is detected by detecting the steering angle.

Therefore, according to the first aspect of the invention, the rotator of the clock spring rotates with the rotation of the steering wheel, and the number of turns of the flexible flat cable with respect to the outer peripheral surface of the rotator and the inner peripheral surface of the outer case changes. Therefore, the steering angle of the steering wheel can be detected by measuring the inductive reactance due to the change in the number of turns.

According to a second aspect of the present invention, in the steering angle detecting device according to the first aspect, the clock spring has a spiral structure in which the flexible flat cable is wound in one direction. It is characterized by the following.

Therefore, according to the second aspect of the present invention, the steering angle of the steering wheel can be detected by the spiral type clock spring.

According to a third aspect of the present invention, in the steering angle detecting device according to the first aspect of the present invention, the clock spring is configured such that the flexible flat cable is turned halfway and the outer case and the rotator are turned in opposite directions. It is characterized in that it has a structure of a winding reversal method.

Therefore, according to the third aspect of the present invention, it is possible to detect the steering angle of the steering wheel using the clock spring of the inversion type.

[0011]

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

In FIG. 1, a clock spring 1 is
It has a cylindrical outer case 2 and an inner rotator 3, and accommodates a flexible flat cable (hereinafter referred to as FFC) 4 between the outer case 2 and the rotator 3. Here, the term “clock spring” is used as a concept that includes all other things called cable reels, rotary connectors, and the like.

The rotator 3 is fixed to a steering shaft (not shown) and has a steering wheel (not shown).
And the outer case 2 is fixed to the steering column side (not shown). FIG. 1 (b) shows the neutral position,
When the rotator 3 rotates clockwise by the steering wheel, the FFC 4 is wound around the rotator 3 (FIG. 1A), and when the rotator 3 rotates left, the FFC 4 is loosened and wound around the inner periphery of the outer case 2 (FIG. 1). (C)).

If the state of FIG. 1A is the maximum right rotation angle of the steering wheel, FIG. 1B is the neutral position, and FIG. 1C is the maximum left rotation angle, the number of turns of the FFC 4 is the maximum of the steering wheel. During the period from the right rotation angle to the maximum left rotation angle, the rotation angle changes in proportion to the rotation angle of the rotator 3, that is, the rotation angle of the steering wheel.

Generally, the inductive reactance of a coil is proportional to the number of turns.
By measuring the inductive reactance of C4, the rotation angle of the steering wheel can be detected. Therefore,
As shown in FIG. 3, a conductor 6 is separately incorporated into the FFC 4 of the clock spring 1, and both ends of the conductor 6 are connected via an inductive reactance measuring device 5 to form a sensing circuit, and the inductive reactance at both ends of the conductor 6 is formed. Is measured by the inductive reactance measuring device 5, the rotation angle of the steering wheel can be detected.

The clock spring shown in FIG.
4 is an example of a spiral type in which the FFC 4 is wound in one direction, but it is needless to say that the present invention can also be implemented by a reverse type clock spring in which the FFC 4 is reversed at the reverse roller 7 as shown in FIG.

FIGS. 4 and 5 show the results of experiments on the change in the induced reactance with respect to the rotation speed of the rotator 3. FIG. FIG. 4 shows the results of the clock spring of the spiral method, and FIG.

In the experiment, the rotator 3 was set on the basis of the neutral position.
Is turned 6 times to the right and 6 times to the left.
Every 25 laps), the induced reactance between the column side circuit and the squib side circuit was measured with an LCR meter. This measurement was repeated twice. The results of FIGS. 4 and 5 are represented by the graphs of FIGS. 6 and 7, respectively.

As is clear from the above experimental results, a constant correlation and reproducibility were recognized between the rotation speed (rotation angle) and the inductive reactance in both the spiral method and the inversion method, and the inductive reactance was determined based on this data. The rotation angle, that is, the steering angle, can be determined from the value of.

As described above, according to the steering angle detecting apparatus of the present embodiment, the steering angle is detected by measuring the inductive reactance due to the change in the number of turns of the FFC 4 of the clock spring 1, so that the steering angle is detected by the FFC 4. It is only necessary to add one conductor 6 for reactance detection, and the sensor board 9 and the detection unit 12 as in the related art become unnecessary, and the steering angle of the steering wheel can be detected compactly and inexpensively.

[0021]

As described above, according to the first aspect of the present invention, the conductor for detecting the steering angle is incorporated in the FFC.
The steering angle of the steering wheel is detected by detecting through the conductor the change in the inductive reactance due to the change in the number of turns of the FFC due to the rotation of the steering wheel. A steering angle detection device can be provided.

According to the second aspect of the present invention, a clock spring having a spiral structure is used.
It is possible to provide a steering angle detecting device having the same effect as the described invention.

Further, according to the third aspect of the present invention, it is possible to provide a steering angle detecting apparatus having the same effect as the first aspect of the present invention by utilizing a clock spring having an inversion type structure.

[Brief description of the drawings]

FIGS. 1A and 1B are plan views showing a spiral type clock spring used in a steering angle detecting device according to an embodiment of the present invention, wherein FIG. 1A shows a clockwise rotation, FIG. )
Indicates a left rotation.

FIG. 2 is a plan view showing an inversion type clock spring used in a steering angle detecting device as another embodiment of the present invention.

FIG. 3 is a diagram showing an example of a sensing circuit for detecting an inductive reactance of the clock spring shown in FIGS. 1 and 2;

FIG. 4 is a diagram showing a result of an experiment on a change in inductive reactance due to a change in the number of revolutions of a spiral type clock spring.

FIG. 5 is a diagram showing a result of an experiment on a change in inductive reactance due to a change in the number of revolutions of a clock spring of an inversion method.

FIG. 6 is a graph showing the experimental results of FIG.

FIG. 7 is a graph showing the experimental results of FIG.

FIG. 8 is a longitudinal sectional side view of a conventional steering angle detecting device.

9 is a perspective view of a part of a sensor board of the steering angle detecting device of FIG. 8;

[Explanation of symbols]

 Reference Signs List 1 clock spring 2 outer case 3 rotator 4 FFC (flexible flat cable) 6 conductor

Claims (3)

[Claims] 1. A flexible flat cable comprising: a rotator that rotates with rotation of a steering wheel; and a clock spring in which an outer case fixed to a steering column is connected by a wound flexible flat cable. Is formed by incorporating a conductor for steering angle detection, and the steering angle of the steering wheel is detected by detecting a change in inductive reactance due to a change in the number of turns of the flexible flat cable via the conductor. A rudder angle detector. 2. The rudder angle detecting device according to claim 1, wherein the clock spring has a spiral structure in which the flexible flat cable is wound in one direction. 3. The rudder according to claim 1, wherein the clock spring has a reversal structure in which the flexible flat cable is reversed midway and wound around the outer case and the rotator in opposite directions. Angle detector.