JPS585626A - Detecting device for steering force - Google Patents

Abstract

PURPOSE:To improve detecting accuracy and durability by providing a light shielding plate on one side of a member which is relatively displaced in correspondence with the displacement with respect to a light shielding plate on the other side, thereby obtaining the steering force. CONSTITUTION:The amount of light, which is varied in correspondence with the amount of the strain yielded between first and second tube parts 11 and 13, is detected in a circuit. In this circuit the following devices are provided: a light emitting photodiode 17 which outputs the detected light to a detecting space 16; a phototransistor 18 which receives the detected light that has passed slits 19a and 20a; a transistor Tr which outputs a voltage value X which is decreased in correspondence with the amount of received light of said transistor 18; a resistor R4 and a capacitor C1 which constitute an integrating citcuit that integrates the voltage value X and holds the maximum value Y; a differential amplifier 22 which outputs the difference signal (Y-X) between the output X of the transistor Tr and the holding value Y; and a driving citcuit 23 which receives the difference signal (Y-X) and holding value Y and outputs the divided signal (Y-X)/Y.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steering force detection device with improved detection accuracy and durability.

For example, as a conventional steering force detection device for controlling a power steering mechanism by detecting the steering force, as shown in FIG. Table 1
The strain gauge 4 is used to detect the strain in the elastic member 3 that occurs depending on the value of the steering force.

However, according to the conventional steering force detection device, depending on the way the strain gauge 40 is attached to the surface of the elastic member 30, there is a risk that a steady strain with variations may occur (the amount of strain on the strain gauge 4 is detected). (The bridge circuit must be adjusted individually according to the variation), so distortion occurs due to thermal expansion and contraction in response to temperature changes.
There are four limits to the improvement of durability, since there is a risk that there is a limit to the improvement in detection accuracy and that cracking or peeling occurs in the strain gauge 4 due to deterioration over time.

In view of the above, the present invention provides a steering system that photoelectrically detects the amount of strain occurring between a steering wheel ring and a steering shaft 7) in accordance with the value of steering force, in order to improve detection accuracy and durability. A force detection device is provided.

The steering force detection device according to the present invention will be explained in detail below.

Figures 2 (a), (b), and G-1 show an embodiment of the present invention, in which a mounting hole 1 is installed in the steering wheel shaft 7) (v!J not shown).
2, a second cylindrical part 13 that is screwed to the steering wheel ring (not shown) side through a mounting hole 14, and a plurality of elastic members 15 interposed between the parts 11.13 and the elastic members 1501 extending radially in order to detect the amount of strain occurring between the first and second cylindrical parts 11.13;
A light-emitting diode 17 and a phototransistor 18 are arranged above and below the detection space 16 and a detection space 16 formed in the second cylindrical part 13 on the second cylindrical part 13. A slit plate 19 (having one axis of the slit, which will be described later) is placed on the slit plate 19 (having one axis of the slit, which will be described later), and one end is fixed to the base of the elastic member 150 via the fixing part 20a, and the other end with the 2Ob tube moves freely into the detection space 16. The slit plate 1 is located at a position corresponding to the amount of strain generated between the first and second cylindrical portions 11 and 130.
It also has a light-shielding plate 20 that shows a relative displacement between the light-emitting diode 17 and the light-emitting diode 17. Although not shown,
The circuit configuration will be described later with reference to FIG. 4K).

Figure 3 0) and (b) show the relative relationship between the slit @19 (having a slit 19m1 corresponding to the slit 20b described above) and the light shielding plate 20, and since no steering force is generated, When no strain occurs between the first and second cylindrical portions 13 and 13, the slit 19a of 9 and the light shielding plate 2o
The slits 19a and 2obva have a completely matching relative relationship (FIG. 3 fO).
Over-rB; increase the amount *! .

Meanwhile, a steering force is generated and the first and second cylindrical portions 11.
When a strain exists between 13 and 13, the amount of light passing through the slits 39m and 20b decreases due to the angular displacement θ depending on the amount of strain.

FIG. 4 shows a circuit tube for detecting the amount of light that changes depending on the amount of strain generated between the first and second cylindrical portions 13 and 130, and the light emitting tie #-)'1 in which the detection light 'tas shines into the detection space 36.
7, a phototransistor that receives the light that has passed through the slits 19m and 20b among the detected light; 8; a transistor Tr that outputs a voltage value X that decreases in response to the amount of light received by the phototransistor 18; The resistor R4 and the capacitor CI (the diode D holds the maximum value Y for a long time), which constitute an integrating circuit that integrates and holds the maximum value Yt-, and the difference signal between the output X of the transistor Tr and the hold value Y (Y -X), and a line signal (Y-X) by manually inputting the difference signal (Y-X) and the hold value Y.
/Y'kaS has a division ratio of 1i11123 (resistances R1, Rz, Rs, R5, @a・family L
Since R8 is self-explanatory, the explanation is omitted).

In the above configuration, according to Figure 5 H), (E”))
The operation is explained as follows.

(Re) When the steering force increases from zero (it often becomes zero at the time of starting) (marked in Figure 5), the angular displacement between (2) light-shielding plate 2o and slit plate]9 changes from zero to the steering force. (e)) The amount of light received by the transistor 18 decreases from its maximum value, and (3) the eye X of the transistor Tr decreases from its maximum value (Fig. 5←)].

(4) Even if the output X decreases, the capacitor 01 retains the force X
Hold value Yl which is the maximum value of
(FIG. 5 (b))] (5) The differential amplifier 22 which receives both signals Y and Xt-λ outputs a difference signal ty-x which increases when the transistor TrI and X decreases (the fifth WJ (B)).

(6) Increasing difference signal output from differential amplifier @22 (
Y - X) and constant hold value Yt - manual division 9 calculation circuit 2
3 outputs the original signal (Y-X)/Y that increases from the minimum value (therefore, when the steering force increases from zero, it outputs the original signal (Y-X)/Yt- that increases from the minimum value. The steering force can be determined from the signal (y-X)/YK.In the above embodiments, it is preferable that the light emitting diode [7] be a light emitting diode with a large light output in the infrared region, but it is not necessarily limited to a light emitting diode. , a light bulb, etc. may be used as a light source.According to this embodiment, since the phototransistor specifically detects the decrease in the light intensity of the light emitting diode due to aging, the sensitivity of the phototransistor decreases. The influence of aging can be completely eliminated.Furthermore, the photoelectric detection mechanism tube steering wheel KM@ may be mounted without adding the first and second cylindrical portions 11.13.

As explained above, according to the steering force detection device according to the present invention, the amount of strain occurring in the elastic coupling member between the steering wheel ring and the steering shaft is optically detected according to the value of the steering force. Therefore, detection accuracy 1 and durability can be improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a conventional steering force detection device. Fig. 2 G (), (cQ, Htj) shows one embodiment of the present invention, 0 is a plan view, (edge is AA sectional view of (A), el is an explanatory diagram showing the light shielding plate 20. The 3rd reason is 0], (This is a theory showing the relationship between the slit plate 19 and the light shielding plate 20! Figure J1.
The figure is an explanatory diagram showing a detection circuit. Time chart of 5th Crystal Figure 4. Explanation of symbols] 1... First cylindrical part 12 - Steering shaft hole] 3 - Second cylindrical part 14 - Mounting hole 15 - Elastic member 16 - Detection space 17 -・Light-emitting diode 3g--Phototransistor 19--Slit, IL 20--Light shielding plate Patent applicant Nissan Motor Co., Ltd. Figure 1 Figure 2 (Incron 15 13 Figure 2 C) Figure 3 ( b) 0a cmouth

Claims (2)

[Claims] (1) A light-shielding plate provided on one side of a member that relatively displaces depending on the steering force (strain); and a photoelectric detection means for photoelectrically detecting the displacement of the light-shielding plate provided on the other side; A steering force detection device comprising a detection circuit tube for inputting a signal from the means and detecting the steering force. (2) The light shielding plate includes a first light passing slit, and the photoelectric detection means includes a light source section that outputs detection light, a light receiving section that receives the detection light, and a space between the light source section and the light receiving section. Located in a SQ plate having a second light passing slit corresponding to the first light passing slit of the light shielding plate, and when the light shielding plate is displaced in response to a steering force, the light receiving portion The steering force detection device according to claim 1, having a configuration for detecting a change in the correspondence between the first and second light passing slits. (2) The steering force detection device according to claim aSS, wherein the detection circuit detects the steering force based on a signal corresponding to a ratio between the signal of the photoelectric detection means and the maximum value of the signal. .