JP2001330473A - Rotation sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation sensor capable of detecting a rotary body regardless of a rotary direction. SOLUTION: In the rotary sensor wherein a Hall IC consisting of at least two Hall elements detects the projection of the rotary body, magnets of which the surfaces showing polarity are different are arranged to the left and right of the Hall IC.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation sensor of a drive system in a control device for controlling a crank angle and a cam angle of an internal combustion engine and a rotating body of a vehicle.

[0002]

2. Description of the Related Art Differential type ICs are well known, and the only feature of the differential type is that the values of two detection media are simply subtracted as they are. The subtracted value and a value obtained by adding a time constant to the subtracted value are compared to form a rectangular wave.

Further, a differential IC is used as a rotation direction detecting means.
Are used to generate a detection phase, and the rotation direction is detected. Furthermore, by inclining only one edge of the detecting protrusion of the rotating body, it is possible to determine whether the inclination is ascending or descending by holding the process of detecting the inclination, and consequently detecting the rotation direction. .

[0004]

In the conventional differential IC as described above, a time constant is taken into consideration. Therefore, in the case where the rotation speed of the rotating body is low, that is, in a so-called low frequency range, a rectangular wave is formed depending on the setting of the time constant. In the case of shaping, a phenomenon occurs in which the edge position of the rectangular wave moves remarkably as the rotation speed increases, and the rectangular wave cannot be shaped in a very low rotation speed region.

When the rotational direction is to be detected by arranging a plurality of differential ICs, the time constant is required as described above. Can not. In addition, since a plurality of ICs are required, the shape to be accommodated becomes large, and the layout of the mounting portion is deteriorated.

[0006]

The detection medium means a medium responsive to magnetism such as a Hall element or a magnetoresistive element.
There is no problem with any medium. In order to solve the above problem, at least three detection media are arranged. When the detection medium is incorporated in the IC, for example, the detection medium A and the detection medium B are arranged on both rotation entry sides of the rotating body. Further, a detection medium C is disposed between the two detection media, and the detection medium A and the detection medium B are required for detecting the detection protrusion of the rotating body. Requires medium A and detection medium B.

According to a first aspect of the present invention, there is provided a rotational position detecting device in which an IC comprising at least two Hall elements or magnetoresistive elements spaced apart from each other detects a protrusion on a rotating body. Are added and subtracted, and each is compared with a non-computed value that is the value of the remaining detection medium to obtain a rectangular wave, and the rectangular wave is input to the latch circuit, so that the detection protrusion of the rotating body is detected. A rotation sensor characterized by being able to obtain a square wave that is a corresponding output.

According to a second aspect of the present invention, an additional non-operation value is obtained by further adding a detection medium between the two detection media, and is compared with the addition / subtraction operation value. The rotation sensor according to claim 1, wherein a rotation direction of the body is detected.

According to a third aspect of the present invention, there is provided a rotation sensor having at least two detection media and a magnet for detecting a projection for detecting a rotating body, wherein one of the detection media is detected by the detection medium. An addition circuit for adding to the detected voltage value and a subtraction circuit for subtraction are connected, and a comparator that processes the addition / subtraction result and a direct output result from another detection medium, and processes an output from the comparator. A rotation sensor comprising a latch circuit, wherein the number of rotations and the rotation direction of the rotation shaft can be detected by an output from the latch circuit.

[0010]

FIG. 1 shows the configuration of the present invention. FIG. 1 shows IC1
FIG. 2 shows a cross-sectional view of a sensor 3 composed of a sensor 2 and a magnet 2. A detection medium A4, a detection medium B5, and a detection medium C6 are built in the IC 1. The magnet 2 is disposed on the back surface of the IC 1 opposite to the rotating body 7 with the IC 1 interposed therebetween. The material of the magnet 2 is not particularly limited. The rotating body 7 that rotates in accordance with the rotation of the shaft of the crank or the cam is provided with detection projections 8 radially on its outer periphery. The projections 8 may be arranged periodically or discontinuously, and the material of the projections 8 is made of a magnetic material such as iron. Here, the “direction of the rotating body 7” means any direction from the detection medium A4 to the detection medium B5 or from the detection medium B5 to the detection medium A4, and is indicated by an arrow in FIG. FIG. 1A shows a state in which the detection projection 8 enters the sensor 3, and FIG. 1B shows a state in which the detection projection 8 is closest to the sensor 3.
(C) shows a state in which the detection projection 8 is separated from the sensor 3. When the rotation direction is reversed, the order is as shown in FIG. 1 (c), FIG. 1 (b), and FIG. 1 (a).

FIG. 2 shows an equivalent circuit of the IC 3 shown in FIG. 1, and FIG. 3 shows a signal waveform at each point in FIG. In FIG. 2, the detection medium A11, the detection medium B12, and the detection medium C13
When detecting the detection protrusion of the rotating body, outputs a voltage corresponding to the detection degree. The output P2 of the detection medium B12 is input to a circuit (addition circuit) 14 for adding an arbitrary voltage to obtain an output P4. Further, the output P2 of the detection medium B12 is input to a circuit (subtraction circuit) 15 for subtracting the voltage at an arbitrary voltage.
Is obtained.

Next, the output P1 and the output P of the detection medium A11 are
4 is input to the comparator 16. The output P1 is input to the non-inverting side of the comparator, and the output P4 is input to the inverting side of the comparator 16. Then, at the timing of T1 in FIG.
6, an output P6 is obtained. Further, the output P1 and the output P5 of the detection medium A11 are input to the comparator 17. The output P1 is input to the non-inverting side of the comparator 17, and the output P5 is
7 is input to the inversion side. Then, the output P7 is obtained from the comparator 17 at the timing of T2 in FIG.

Next, the output P is output to the set side of the latch circuit 20.
6 is input and the output P7 is output to the reset side of the latch circuit 20.
Is entered. In the latch circuit 20, the output P8 becomes "HIGH" as shown in FIG. 3 at the timing of T1 in FIG.
The output P8 becomes "LOW" at the timing of T2 in FIG. 3 as shown in FIG. That is, it is possible to output “HIGH” from the output P8 when the detection protrusion of the rotating body enters, and to output “LOW” from the output P8 when the detection protrusion of the rotating body separates. Recognizes the projection for detecting the rotating body irrespective of the rotation speed except for the operation delay of the semiconductor.

The output P3 of the detection medium C13 and the output P
6 is input to the comparator 18. The output P3 is input to the non-inverting side of the comparator 18, and the output P4 is input to the inverting side of the comparator 18. Then, the output P9 is obtained from the comparator 18 at the timing of T3 in FIG. Further, the output P3 and the output P5 of the detection medium C13 are input to the comparator 19. Output P
3 is input to the non-inverting side of the comparator 19, and the output P5 is input to the inverting side of the comparator 19. Then, the output P10 is obtained from the comparator 19 at the timing of T4 in FIG.

Next, the output P is output to the set side of the latch circuit 21.
9 is input and the output P1 is output to the reset side of the latch circuit 21.
0 is input. In the latch circuit 21, the output P11 becomes "HIG" at the timing of T3 in FIG.
H, and the output P11 becomes "LOW" at the timing of T4 in Fig. 3. That is, "HIGH" is output from the output P11 when the detecting protrusion of the rotating body enters.
"LO" from output P11 when the detection protrusion of the rotating body is detached.
W "can be output, and this output P11 recognizes the detection projection of the rotating body regardless of the number of rotations, except for the operation delay of the semiconductor.

At the rising timing T1 of "HIGH" of the output P8, the rising timing T3 of "HIGH" of the output P11, and the falling timing T2 of "LOW" of the output P8, in the order of T1, T3, T2. When the timing is established, it is possible to recognize the normal rotation, and when the timing is established in the order of T3, T1, and T2, it is possible to recognize the reverse rotation.

As described above, since the time constant is not taken into consideration in the circuit of FIG. 2 constructed according to the present invention, the detection projection of the rotating body can be output at a fixed position without depending on the number of revolutions, On the other hand, accurate recognition can be achieved without depending on the rotation speed.

[0018]

According to the above configuration, the detection projection can be recognized at a substantially constant position without depending on the rotation number of the detection projection of the rotating body, that is, an output corresponding to the detection projection can be obtained. Further, the rotation direction of the rotating body can be recognized without depending on the rotation speed.

[Brief description of the drawings]

FIG. 1 shows a structural diagram of a rotation sensor of the present invention.

FIG. 2 shows an equivalent circuit diagram of FIG.

FIG. 3 shows a signal waveform at each point in FIG.

[Explanation of symbols]

 In the drawings, the same reference numerals indicate the same or corresponding parts. DESCRIPTION OF SYMBOLS 1 IC 2 Magnet 3 Sensor 4, 5, 6 Detection medium 7 Rotating body 8 Detection projection 11, 12, 13 Detection medium 14 Addition circuit 15 Subtraction circuit 16, 17, 18, 19 Comparator 20, 21 Latch circuit

Claims (3)

[Claims] An IC comprising at least two Hall elements or magneto-resistive elements spaced apart from each other detects a protrusion on a rotating body, and adds an arbitrary value to one of the two detection media. And a subtraction, and comparing the non-calculated values, which are the values of the remaining detection media, respectively, to obtain rectangular waves, and inputting the rectangular waves to the latch circuit to obtain the output corresponding to the detection protrusion of the rotating body. A rotation sensor capable of obtaining a certain rectangular wave. 2. An additional non-operation value is obtained by further adding a detection medium between two detection media, and the obtained non-operation value is compared with an operation value obtained by addition / subtraction. The rotation sensor according to claim 1, wherein 3. A rotation sensor, comprising at least two detection media and a magnet, for detecting a detection projection of a rotating body, wherein one of the detection media has a detection voltage value detected by the detection medium. An addition circuit for performing addition and a subtraction circuit for performing subtraction are connected, and a comparator that processes the addition / subtraction result and a direct output result from another detection medium, and a latch circuit that processes an output from the comparator are provided. A rotation sensor, wherein the number of rotations and the rotation direction of the rotation shaft can be detected by an output from the latch circuit.