JPH035506Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steering angle detection device for an automobile that can reliably detect the neutral position of a steering wheel with a simple configuration.

Considerations have been made to display a pictorial display of the direction of the tires, or to turn on cornering lamps when the rotation angle of the steering wheel, that is, the steering angle, reaches a predetermined angle. A detection method has been proposed.

FIG. 1 shows one of the conventional steering angle detection devices, in which a rotating plate 2 having a large number of slits provided at equal intervals along the periphery is fixed to a steering shaft 1, and this rotating plate 2 is sandwiched between the steering shaft 1 and the steering shaft 1. Light emitting element 3
and a light receiving element 4 are arranged facing each other.
When the driver turns the steering wheel 5, a light pulse corresponding to the rotation angle, that is, the steering angle, is received by the light receiving element 4 and extracted as an electrical signal. When the handle 5 is turned clockwise by a predetermined angle or more, the pitman arm 6 rotates in the direction A and its operating rod 6a closes the switch _W1 , as shown in FIG. As a result, the lamp _R1 lights up in a circuit as shown in FIG. 3, and the right steering direction is displayed. When the handle 5 is turned to the left by a predetermined angle or more, the pitman arm ₆ rotates in the direction B as shown in FIG _.
lights up. In this way, the magnitude and direction of the steering angle are displayed at the same time, and if both lamps R ₁ and R ₂ are off, it can be seen that the vehicle is in the neutral position.

In such a steering angle detection device, dedicated switches W ₁ and W ₂ are installed in the steering mechanism to detect the direction of the steering angle or the neutral position, but they are installed at a relatively low location at the front of the vehicle. Due to its location, it may come into contact with water or dust,
Sensitive to temperature changes. For this reason, it is necessary to have a waterproof structure and to take measures against heat, which raises the problem of high costs. Also, since it is a mechanical switch, there are limits to its reliability.

The present invention has been developed in view of the above points, and in order to reliably detect the neutral position of the steering wheel with a simple configuration, a reference position detection means for detecting the reference position of the steering wheel is provided. The steering wheel is determined to be in the neutral position when the steering wheel is in the reference position for a predetermined period of time or longer.

The present invention will be explained below based on the drawings.

FIG. 4 shows a main part of an embodiment of the steering angle detector used in the steering angle detecting device according to the present invention. It consists of a slit 8a and one slit 8b formed inside the slit 8a for detecting a reference position (corresponding to the neutral position of the steering wheel).A light emitting element _C1 is arranged above the slit 8a, and the rotating plate 7 is connected to the slit 8a. The light-receiving elements _D1 are arranged opposite to each other with a sandwich between them. Further, a light emitting element C ₂ is placed opposite to the passageway of the slit 8b across the rotary plate 7.
and a light receiving element _D2 are arranged.

FIG. 5 is a block diagram of the steering angle detection device, in which reference numeral 9 denotes a vehicle speed sensor for detecting vehicle speed;
0b is a counter, 11 is a comparator that compares the vehicle speed V _C with a reference value V ₀ , 12 is a light receiving circuit that outputs an H level based on the ON signal output when the light receiving element D ₂ receives light, 13 is an AND circuit, and 14 is an AND H of circuit 13
A timer 15 is a NOT circuit which is triggered when a level is applied to the set terminal and is reset when the reset terminal R is at H level.

Next, the circuit operation will be explained.

When the steering wheel is rotated, the rotary plate 7 rotates, and the steering angle is detected by pulsed light received by the light receiving element _D1 from the light emitting element _C1 through the slit 8a. On the other hand, the reference position of the steering wheel is detected by the pulsed light received by the light receiving element _D2 from the light emitting element _C2 through the slit 8b. This reference position may correspond to the neutral position of the steering wheel, but it may also be a position corresponding to the neutral position after one or two rotations, so it is not always possible to detect the neutral position using this signal. Therefore, the logic circuit shown in FIG. 5 was added to detect the neutral position of the steering wheel, making it possible to detect the absolute angle from the neutral position of the steering wheel. That is, in FIG. 5, the pulse from the vehicle speed sensor 9 is
0a, and the value is compared with the reference vehicle speed V ₀ by the comparator 11. As a result, when the vehicle speed is higher than a predetermined constant vehicle speed V ₀ (for example, 50 km/hour),
Comparator 11 outputs an H level signal. On the other hand, since the light receiving circuit 12 outputs an H level signal when the light receiving element D ₂ receives light, when the vehicle speed is greater than the reference vehicle speed V ₀ and the steering wheel is at the reference position,
AND circuit 13 outputs H level, and timer 1
Trigger 4. When this state continues for a certain period of time, the timer 14 outputs an H level and resets the counter 10b. That is, when the vehicle is at a constant vehicle speed _V0 or higher and the steering wheel remains at the reference position for a certain period of time or more, it is determined that the vehicle is traveling straight, and the counter 10b, which is a means for counting the steering angle pulse P, is reset. do. Therefore, the subsequent count value S of the counter 10b represents the absolute angle from the neutral position of the steering wheel. Further, when either one of the inputs of the AND circuit 13 is at the L level, the AND circuit 13 also goes to the L level, and the timer 14 is reset by the NOT circuit 15 applying the H level to the inverted reset terminal R.

As explained above, in the present invention, when the vehicle speed is above a certain speed and the steering wheel is at the reference position for a certain period of time or more, it is determined that the steering wheel is in the neutral position, and the steering angle pulse counter is reset. Of course, it is possible to detect the steering angle from the neutral position of the steering wheel, but it also eliminates the need for a switch to detect the neutral position. reliability is improved. Furthermore, the counter that detects the steering angle is reset when the vehicle speed is above a certain speed and the steering wheel is at the reference position for a certain period of time or more, so even if erroneous information such as noise is counted, each time the counter is reset. Since the steering angle is canceled, the reliability of the detected steering angle is increased.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing how a conventional steering angle detecting device is installed, Fig. 2 is a perspective view showing how a steering rotation direction detection switch in a conventional steering angle detecting device is installed, and Fig. 3 is a conventional steering angle detecting device. FIG. 4 is a perspective view of a rotating plate used in the steering angle detector of the steering angle detecting device according to the present invention; FIG. 5 is a lamp circuit indicating the rotational direction of the steering wheel in the steering angle detecting device according to the present invention FIG. 3 is a block diagram of one embodiment. 7...Rotating plate, 8a, 8b...Slit, 9...
...Vehicle speed sensor, 10a, 10b...Counter, 1
1... Comparator, 12... Light receiving circuit, 13...
AND circuit, 14...timer, _C1 , _C2 ...light emitting element, _D1 , _D2 ...light receiving element.

Claims (1)

[Scope of utility model registration request] A steering angle sensor outputs a number of steering angle pulse signals proportional to the rotation angle of a steering shaft that rotates together with a steering wheel that can rotate at least one rotation, and the steering angle pulse signals output from the steering angle sensor are counted. a counting means for outputting the counted value as a steering angle; a reference position detection sensor for detecting one steering wheel reference position per rotation of the steering shaft; A steering angle detection device for an automobile, comprising a reset means for resetting the counting means when the counting means is at the reference position.