JPH09243311A - Rotary angle detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the detection characteristic of a rotary angle detecting device and to greatly enhance the durability and reliability of the device by enabling the device to output signals having linear characteristics with respect to the rotary angle of a rotating shaft, etc. SOLUTION: A rotatable magnet 4 has circular surface parts 4A, 4B formed over an angle θm1. First 5 and second 6 magnetic pole pieces, which surround the magnet 4 with a certain gap held between each of them and the magnet, are arranged at an interval greater than the gap, the magnetic pole pieces 5, 6 being formed along the circumferential direction over an angle θy1 smaller than the angle θm1. The first ends of magnetic path forming parts 7, 8, 9, 10 are connected to the magnetic pole pieces 5, 6, a first Hall element 11 is provided between the ends 7A, 8A of the magnetic path forming parts 7, 8, and a second Hall element 12 is provided between the ends 9A, 10A of the magnetic path forming parts 9, 10. A computing circuit which outputs a detection signal corresponding to a rotary angle θ1 according to voltages output from the first and second Hall elements 1, 12 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning angle detecting device preferably used for detecting a turning angle of a turning shaft, and more particularly to detecting a throttle valve opening of an automobile engine. Of the rotation angle detecting device.

[0002]

2. Description of the Related Art Generally, in an automobile engine or the like equipped with an electronically controlled fuel injection device, the opening of a throttle valve provided in the intake passage of the engine is detected and input to a control unit. The accuracy of fuel injection amount control is improved.

In the prior art of this type, a potentiometer consisting of a resistor and a brush is used to detect the opening of the throttle valve, and the brush side is used for the rotary shaft (valve shaft) of the throttle valve. ), The brush is slidably displaced on the resistor according to the rotation of the throttle valve, and the resistance value change of the resistor is detected as the opening of the throttle valve.

As another conventional technique, for example, Japanese Patent Laid-Open No. 2-298814 discloses a non-contact type rotation angle detecting device using a magnetoresistive element. And
In the case of this type of rotation angle detection device, a magnetic field is generated around a fixed magnetic resistance element by a magnet, and this magnet is rotated in conjunction with a shaft to rotate the magnetic field around the magnetic resistance element. The change of the rotation angle at this time is detected as the change of the resistance value of the magnetoresistive element so that the opening degree of the throttle valve and the like can be detected.

[0005]

By the way, in the rotation angle detecting device according to the prior art described above, when the potentiometer is used, the brush slides on the resistor, so that the momentary output is caused by the floating of the brush. The signal is blocked. Also,
There is also a problem that durability and reliability will deteriorate due to abrasion of the brush etc. in long-term use, and it sufficiently copes with the increase in service life of automobiles in recent years and the increase in feedback control accompanying electronic computerization of throttle valve control. There is a problem that you cannot do it.

On the other hand, when the magnetoresistive element is used, the distance between the magnetic arm provided on the magnet side and the magnetoresistive element is largely changed by the rotation of the shaft (magnet), and Output signal has a trigonometric function characteristic with respect to the rotation angle of the shaft, so that it is difficult to obtain linear characteristics when detecting the opening (rotation angle) of the throttle valve. .

Further, when the magnetoresistive element is used, there is a problem that the change in output signal is large due to the temperature change of the magnetomotive force of the magnet, the change over time, the temperature characteristic of the magnetoresistive element, etc., and it is difficult to correct this. is there.

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention can output a signal having a linear characteristic with respect to a rotation angle of a rotation shaft or the like, and can stabilize the detection characteristic. At the same time, it is an object of the present invention to provide a rotation angle detection device capable of greatly improving durability and reliability.

[0009]

In order to solve the above-mentioned problems, the structure of the rotation angle detecting device adopted by the invention described in claim 1 is a magnet having an arc surface portion, and an arc surface portion of the magnet. Any one of at least three or more magnetic pole pieces, which are arranged so as to face each other and are spaced apart from each other around the magnet, and extend at a predetermined angle in the circumferential direction, and each magnetic pole piece and the magnet. Rotating means for rotating one of the magnetic pole pieces and the magnet relative to each other, and first and second signals generated corresponding to the facing area of the arc surface of the magnet and each magnetic pole piece. Signal output means for respectively outputting the magnetic pole pieces, and the distance between the magnetic pole piece portions is larger than the gap between the magnet and the magnetic pole piece portions.

With this configuration, the magnetic pole pieces that rotate relative to each other and the magnet can be held in a non-contact state, and the distance between the magnetic pole pieces and the magnet can be kept constant. The facing area between each of the magnetic pole pieces and the magnet can be changed according to the rotation angle. Further, since the gap between the magnet and each pole piece is formed smaller than the distance between the pole pieces, the arc surface of the magnet can be brought closer to each pole piece, and the magnetic flux can be reliably applied to each pole piece. I can guide you.

According to the second aspect of the present invention, the magnet having the arcuate surface portion is provided around the magnet so as to be opposed to the arcuate surface portion of the magnet, and the magnets are predetermined in the circumferential direction. At least three magnetic pole pieces extending at a predetermined angle, and a rotating means for rotating any one of the magnetic pole pieces and the magnet to relatively rotate the magnetic pole pieces and the magnet. , Signal output means for respectively outputting first and second signals generated corresponding to the facing area of the arc surface portion of the magnet and the respective magnetic pole piece portions, and the distance between the magnetic pole piece portions is Make it larger than the gap between the magnet and each pole piece,
Further, the arc surface portion of the magnet is configured to extend at a larger angle in the circumferential direction than at least one of the magnetic pole piece portions.

With this structure, the area of the one magnetic pole piece facing the magnet can be changed over the entire circumference in accordance with the rotation angle, and each of the magnets faces the arc surface. It is possible to reliably guide the magnetic flux to the pole piece.

On the other hand, according to the third aspect of the present invention, the rotation angle detecting device is arranged around the magnet so as to face the magnet having the arcuate surface portion and the arcuate surface portion of the magnet. A pair of first magnetic pole piece portions extending at a predetermined angle in the circumferential direction, and arranged between the first magnetic pole piece portions apart from the first magnetic pole piece portions,
A pair of second extending in a circumferential direction at a predetermined angle
Of the magnetic pole piece portion, the first and second magnetic pole piece portions, and the magnet are rotated to relatively rotate the first and second magnetic pole piece portions and the magnet. Moving means,
A first and a second signal output means for respectively outputting first and second signals generated corresponding to the facing areas of the first and second magnetic pole pieces and the arc surface of the magnet, The distance between the magnetic pole pieces is larger than the gap between the magnet and the magnetic pole pieces.

With this structure, the first and second magnetic pole pieces that rotate relative to each other and the magnet can be held in a non-contact state, and the first and second magnetic pole pieces and the magnet can be held. Can be kept constant, and the facing area between the first and second magnetic pole piece portions and the magnet can be changed in accordance with the rotation angle. Further, since the distance between the magnetic pole pieces is larger than the gap between the magnet and the magnetic pole pieces, the magnetic flux can be surely guided to the magnetic pole pieces facing the arc surface of the magnet. Further, the first signal output means can output a first signal corresponding to an area (magnetic field) facing the magnet between the first magnetic pole piece portions, and the second signal output means, Since the second signal corresponding to the area (magnetic field) facing the magnet can be output between the second magnetic pole pieces, the first and second magnetic pole pieces can be output.
The respective signal levels output from the signal output means can be largely changed according to the relative rotation of the magnet or the like.

According to a fourth aspect of the invention, the arcuate surface portion of the magnet extends at a larger angle in the circumferential direction than at least one magnetic pole piece portion of the first and second magnetic pole piece portions. It is configured.

With this structure, the facing area with the magnet can be changed over the entire circumference of each one of the magnetic pole pieces in accordance with the rotation angle, and the facing area faces the arc surface of the magnet. The magnetic flux can be reliably guided to each magnetic pole piece, and the leakage magnetic flux can be reduced.

Further, in the invention according to claim 5, the arcuate surface portion of the magnet is more circumferential than the angle between at least one of the magnetic pole pieces between the first and second magnetic pole pieces. It is configured to extend at a small angle.

With this configuration, it is possible to prevent the leakage magnetic flux from being guided to the first and second magnetic pole pieces, and it is possible to accurately detect the rotation angle.

Furthermore, in the invention according to claim 6,
An arithmetic means is provided for arithmetically outputting a detection signal corresponding to the turning angle of the turning means based on the first and second signals output from the first and second signal output means.

With this configuration, of the signal components included in the first signal and the second signal, the components that are greatly affected by the magnetomotive force of the magnet, the temperature characteristics, etc. It is possible to cancel the two signals and prevent the detection signal from changing in accordance with the ambient temperature and the like.

[0021]

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

Here, FIGS. 1 to 6 show examples in which the turning angle detecting device according to the first embodiment of the present invention is applied to the detection of the opening degree of a throttle valve.

In FIG. 1, reference numeral 1 denotes a casing made of a resin material, and the casing 1 is a cylindrical portion 1 opening downward.
A, a thick-walled plate-shaped partition wall portion 1B for covering the upper side of the tubular portion 1A, and a recessed portion 1C recessed in an upper portion of the partition wall portion 1B
It is composed of Then, the tubular portion 1 of the casing 1
A is inserted into a recess 2A of the throttle body 2, and a shaft 3 as a rotating means (rotating shaft) that rotates in conjunction with a throttle valve (not shown) is provided in the throttle body 2.
Are rotatably provided.

Reference numeral 4 denotes a magnet disposed inside the cylindrical portion 1A of the casing 1. The magnet 4 is attached to the tip end side of the shaft 3 by caulking or the like and protrudes from the shaft 3 in the radial direction. Here, as shown in FIG. 2, the magnet 4 has arcuate surface portions 4A and 4B on both longitudinal ends,
Both side surfaces in the width direction are parallel surface portions 4C and 4D. The arcuate surface portions 4A and 4B of the magnet 4 are the shaft 3
With a constant radius (curvature) centered around, extending in the circumferential direction over an angle θm1 range, and magnetic poles (N pole, S pole) on the end face side.
Are formed. Further, a through hole 4E extending in the axial direction of the shaft 3 is provided at the center of the magnet 4, and the through hole 4E has a shape similar to that of the magnet 4, and the magnet 4 is fixed to the shaft 3 in a non-rotating state. It is designed to let you.

Reference numerals 5 and 5 denote first magnetic pole piece portions embedded in the cylindrical portion 1A of the casing 1. The first magnetic pole piece portions 5 and 5 are, as shown in FIG. It has a split cylindrical shape that surrounds the magnet 4 in an annular shape together with the pieces 6 and 6. The magnetic pole pieces 5, 5 are arranged at symmetrical positions in the radial direction around the shaft 3, and each magnetic pole piece 5 and the arcuate surface portions 4A, 4B of the magnet 4 have a constant gap G1.
With the shaft 3 as the center so that they face each other through
It extends in the circumferential direction over the range of y1. Here, each magnetic pole piece 5 has an angle θy1 of each arc surface 4A of the magnet 4,
Formed smaller than the angle θm1 of 4B (θy1 <θm1),
Each magnetic pole piece 5 guides the magnetic flux generated by the magnet 4 to the first Hall element 11 via the first magnetic path forming portions 7 and 8 described later.

Numerals 6 and 6 are located between the magnetic pole pieces 5 and 5 with a separation dimension a1 (angle θa1) longer than the gap G1 from each magnetic pole piece 5 and are embedded in the cylindrical portion 1A of the casing 1. A magnetic pole piece portion is shown, and the second magnetic pole piece portions 6 and 6 face the circular arc surface portions 4A and 4B of the magnet 4 with a gap G1 at a constant interval, like the first magnetic pole piece portions 5 and 5. The shaft 3 extends in the circumferential direction over the range of the angle θy1. Further, the magnetic pole piece portions 6, 6 (5, 5)
The angle (θy1 + 2θa1) between them is larger than the angle θm1 of the arc surface portions 4A and 4B of the magnet 4 (θm1 <θy1 + 2θ).
a1) is formed. In this case, the sum of the angle θy1 at which the magnetic pole pieces 5 and 6 extend in the circumferential direction and the angle θa1 at which the magnetic pole pieces 5 and 6 are separated from each other is the angle of each of the arc surface portions 4A and 4B of the magnet 4. Greater than θm1 (θm1 <
θy1 + θa1) It is desirable to form. Each of the magnetic pole pieces 6 guides the magnetic flux generated by the magnet 4 to the second Hall element 12 via the second magnetic path forming portions 9 and 10 described later.

As shown in FIG. 2, the rotation angle θ1 of the magnet 4 (shaft 3) is zero (0) when the central portion of the arcuate surface portion 4A faces the intermediate portion 6A of the pole piece 6 on one side. θ 1 = 0 °) position, when the arc surface 4A of the magnet 4 is rotated clockwise from the intermediate portion 6A of the magnetic pole piece 6, the magnet 4 is rotated counterclockwise from the intermediate portion 6A of the magnetic pole piece 6. The negative direction is when the arc surface portion 4A is rotated.

Reference numerals 7 and 8 denote magnetic path forming portions whose base ends are connected to the first magnetic pole piece portions 5 and 5 and whose tip ends project into the recess 1C of the casing 1. The tip end sides of the magnetic path forming portions 7 are shown. Covers the upper side of the first Hall element 11 via a gap, and the tip side of the magnetic path forming portion 8 is arranged so as to extend on the partition wall portion 1B of the casing 1 along the back surface of the circuit board 13 described later. There is. As shown in FIG. 4, the tip portion 7A of the magnetic path forming portion 7 is disposed so as to face the tip portion 8A of the magnetic path forming portion 8 located below the Hall element 11, which will be described later. The Hall element 11 and so on are inserted.

Numerals 9 and 10 have second magnetic pole piece portions 6 and 6 on the base end side.
The magnetic path forming portion that is connected to the magnetic path forming portion 9 and has a tip side protruding into the concave portion 1C of the casing 1.
The upper side of the Hall element 11 is covered with a gap, and the tip end side of the magnetic path forming portion 10 is arranged so as to extend above the partition wall portion 1B of the casing 1 along the back surface of the circuit board 13 described later. As shown in FIG. 4, the tip portion 9A of the magnetic path forming portion 9 is disposed so as to face the tip portion 10A of the magnetic path forming portion 10 located below the Hall element 12, which will be described later. The Hall element 12 and the like are inserted.

Here, the tip portions 7A of the magnetic path forming portions 7 and 8 are
As shown in FIG. 4, the area where 8A faces is the magnetic path forming portion 9,
The tip end portions 9A, 10A of 10 have an area equal to the area where they face each other, and the gap dimension b1 between them is configured to be a constant dimension.

Reference numerals 11 and 12 denote Hall elements provided on the circuit board 13 as first and second signal output means,
The first and second Hall elements 11 and 12 are one chip (one chip) on the circuit board 13 so as to be in parallel relationship with each other.
Are arranged. And the first Hall element 1
As shown in FIG. 4, 1 is located between the front end portion 7A of the magnetic path forming portion 7 and the front end portion 8A of the magnetic path forming portion 8, and the first signal proportional to the magnetic flux density between them is shown in FIG. Output voltage E as shown in
It is output as 11. On the other hand, the second Hall element 12 is located between the tip portion 9A of the magnetic path forming portion 9 and the tip portion 10A of the magnetic path forming portion 10, and a second signal proportional to the magnetic flux density between them is shown. It is output as an output voltage E12 as shown in FIG.

Reference numeral 13 denotes a circuit board which is located in the concave portion 1C of the casing 1 and mounts the first and second Hall elements 11 and 12 and an arithmetic circuit 19 which will be described later. The circuit board 13 corresponds to the Hall elements 11 and 12. The mounting portions are the tip portions 7A and 9A of the magnetic path forming portions 7 and 9 and the tip portions 8A and 1 of the magnetic path forming portions 8 and 10.
The circuit board 1 is arranged so as to be positioned between the circuit board 1 and
One end side of each terminal pin 14 described later is fixed to the tip side of 3 in a state of penetrating from the partition wall 1B toward the cover 16 side described below.

Reference numeral 14 denotes a plurality of terminal pins (only one is shown) embedded in the casing 1 and made of a metallic material. One end of each terminal pin 14 projects into the recess 1C of the casing 1 and penetrates the circuit board 13. It is fixed in the state, the other end side projects into the male connector 15 described later, and can be electrically connected to an external terminal. Each terminal pin 14 connects the first and second Hall elements 11 and 12 and an arithmetic circuit 19 described later to an external power source (not shown) or the like, and outputs a detection signal So1 described later by the arithmetic circuit 19 to the outside. It is configured to output to.

Reference numeral 15 denotes a substantially rectangular tube-shaped male connector formed to project from the casing 1, and the other end of the terminal pin 14 projects into the male connector 15. The male connector 15 is connected to a mating female connector (not shown) via each terminal pin 14.

Reference numeral 16 is a cover made of a synthetic resin material and having a substantially flat plate shape for sealing the inside of the recess 1C of the casing 1 in a closed state, and 17 is a packing formed of an elastic material for sealing between the cover 16 and the casing 1. Is shown.

Reference numeral 18 denotes a flat magnetic shield plate embedded in the partition wall 1B of the casing 1. The magnetic shield plate 18 is located below the first and second Hall elements 11 and 12, and the magnet 4 Magnetic field from the first and second Hall elements 11,
12 to prevent it from directly affecting.

Reference numeral 19 is an output voltage E1 mounted on the circuit board 13 and output from the first and second Hall elements 11 and 12.
1 and E12 show an arithmetic circuit as an arithmetic means for arithmetically outputting the detection signal So1 corresponding to the rotation angle. The arithmetic circuit 19 includes an absolute value assigner 20, an adder 21, and an adder 21, which will be described later, as shown in FIG. The divider 22 and the amplifier 23 are included.

Reference numeral 20 denotes an absolute value assignor for outputting the absolute value of the output voltage E11 output from the first Hall element 11, 21
Is the output from the absolute value assigner 20 and the second Hall element 12
An adder for adding the output voltage E12 output from the adder 22; a divider 22 for taking a ratio between the output of the adder 21 and the output voltage E11;
Reference numeral 23 denotes an amplifier that amplifies the output of the divider 22. The amplifier 23 is electrically connected to each terminal pin 14 and outputs the detection signal So1 corresponding to the rotation angle to each terminal pin 1.
Output to the outside via 4.

Reference numeral 24 is a reference voltage generator for determining an offset level with respect to the output of the divider 22, and reference numeral 25 is an adjustment signal generator for correcting the output signal of the amplifier 23 and adjusting (correcting) the output characteristic of the signal to a linear characteristic. Showing the vessel.

That is, the absolute value adder 20 of the arithmetic circuit 19 obtains the absolute value | E11 | of the output voltage E11, and the adder 21 adds the absolute value | E11 | and the output voltage E12 to obtain the added value (| E11 | | + E12) Then, the divider 22 divides the added value (| E11 | + E12) and the output voltage E11,

[0041]

[Equation 1] Then, the calculation signal Sx1 shown in FIG. 6 is output.

As a result, the calculation signal Sx1 becomes the rotation angle θ1.
Is 0 °, the minimum value (Sx1 = 0) and the rotation angle θ1
Is 90 °, the maximum value (Sx1 = 1) is reached. And
The calculation signal Sx1 is determined only by the rotation angle .theta.1 and is not affected by the magnetomotive force F1 of the magnet 4 and the element sensitivity G of the Hall elements 11 and 12 by the equations 7 to 14 described later.

The reference voltage generator 24 inputs the reference voltage to the divider 22, the amplifier 23 amplifies the operation signal Sx1 output from the divider 22, and the adjustment signal generator 25 adjusts the amplifier 23. By inputting the signal, the minute fluctuation of the detection signal So1 output from the amplifier 23 is corrected.

That is, the detection signal So1 is based on the operation signal Sx1,

[0045]

[Equation 2] Is required.

Here, Vo1 is a constant voltage value (for example, 2.
5V), and the constant k indicates a constant amplification factor. The detection signal So1 has a minimum value (Vo1−k) when the rotation angle θ1 is −90 °, and has a maximum value (Vo1 + k) when the rotation angle θ1 is 90 °.

The turning angle detecting device according to the present embodiment has the above-mentioned structure, and its detecting operation will be described below.

First, the principle of detecting the rotation angle will be described with reference to FIGS. 7 to 11. In the comparative example shown in FIG. 7, the arcuate surface portion 4A of the magnet 4 has an angle θm1 of approximately 90 °. Once set, the angle θ of each pole piece 5, 6
y1 is also set to approximately 90 °, and it is premised that the distance a1 (angle θa1) between the first and second magnetic pole piece portions 5 and 6 is set to a very small value.

Then, as shown in FIG. 8, as the shaft 3 rotates, the arcuate surface portion 4A of the magnet 4 rotates in the circumferential direction at a rotation angle θ1 within a range of ± 90 ° from the intermediate portion 6A of the magnetic pole piece portion 6 on one side. When the magnet 4 is rotated in the positive direction, the arc surface 4A of the magnet 4 faces the pole piece 5 on one side (the right side in FIG. 8) over the range of the angle θ11 and the angle θ12. It opposes the pole piece 6 on one side (the upper side in FIG. 8) over the range.

Similarly, the arcuate surface 4B of the magnet 4 faces the other side (left side of FIG. 8) of the magnetic pole piece 5 over the range of the angle θ11, and the other side (see FIG. 8) over the range of the angle θ12.
The lower magnetic pole piece 6 faces. Then, the magnetic flux generated from the magnet 4 is guided from the first magnetic pole piece portions 5 and 5 to the first Hall element 11 through the magnetic path forming portions 7 and 8, while it is discharged from the second magnetic pole piece portions 6 and 6. Magnetic path forming section 9, 10
Through the second Hall element 12.

At this time, the magnet 4, the magnetic pole pieces 5,
As shown in FIG. 9, 6 is a magnet 4, magnetic pole pieces 5, 5
And the magnetic path forming portions 7 and 8 constitute a first magnetic circuit, the magnet 4, the magnetic pole piece portions 6 and 6 and the magnetic path forming portions 9 and 10 constitute a second magnetic circuit, and two magnetic circuits are formed. The circuits are magnetically connected in parallel.

Here, if the reciprocal of the magnetic resistance generated between the circular arc surface portion 4A of the magnet 4 and the magnetic pole piece portions 5 and 6 on one side is permeances P11 and P12, these permeances P11 and P12 are Arc surface 4A and first and second
Is substantially proportional to the area of the magnetic pole pieces 5 and 6 facing each other,

[0053]

## EQU3 ## P11 = α1 × μ0 × θ11 = α1 × μ0 × θ1

[0054]

[Equation 4] P12 = α1 × μ0 × θ12 = α1 × μ0 × (90 ° −θ1)

Here, the constant α1 is a constant value determined in advance by the axial dimension of the magnet 4, the axial dimension of the magnetic pole pieces 5, 6 and the distance between the magnet 4 and the magnetic pole pieces 5, 6. And the magnetic permeability μ 0 indicates the magnetic permeability in vacuum.

If the reciprocal of the magnetic resistance generated between the arc surface 4B of the magnet 4 and the magnetic pole pieces 5, 6 on the other side is permeance P13, P14, the arc surface 4B and the magnetic pole piece 5 on the other side. , 6 is equal to the facing area of the arcuate surface portion 4A and the pole piece portions 5, 6 on one side,

[0057]

[Equation 5] P13 = α1 × μ0 × θ11 = P11

[0058]

## EQU6 ## The relationship of P14 = α1 × μ0 × θ12 = P12 is established.

At this time, the first and second Hall elements 11,
Assuming that the reciprocal of the magnetic resistance generated by the circumference of 12 is permeance PS1, this permeance PS1 is the permeance P11, P12, P13, P14 on the side of the first and second magnetic pole pieces 5, 6.
The permeance P is sufficiently small compared to
S1 is a value that can be practically ignored.

Therefore, the total magnetic flux Φ1 generated by the magnetomotive force F1 of the magnet 4 and passing through the first and second magnetic circuits is

[0061]

(Equation 7) The relationship is always constant.

Further, the magnetic flux Φ11 passing through the magnetic pole pieces 5 and 6,
Φ12 has a relationship of Φ11: Φ12 = P11: P12, and

[0063]

(Equation 8)

[0064]

[Equation 9] Is required.

Here, the tip portions 7A of the magnetic path forming portions 7 and 8 are
The area where 8A faces is the tip portion 9 of the magnetic path forming portions 9 and 10.
Since A and 10A are equal to the facing area, if the constant due to this facing area is β1, the first and second Hall elements 1
The magnetic flux densities B11 and B12 passing through 1 and 12 are

[0066]

[Equation 10] B11 = β1 × Φ11

[0067]

[Equation 11] B12 = β1 × Φ12.

The hall elements 11 and 12 have the same characteristics, and the output voltages E11 and E12 of the hall elements 11 and 12 are the same.
Is proportional to the magnetic flux densities B11 and B12,

[0069]

[Equation 12] E11 = G × B11 = G × β1 × Φ1 × θ1 / 90 °

[0070]

[Equation 13] E12 = G × B12 = G × β1 × Φ1 × (1-θ1 / 90 °). Here, G is the element sensitivity of the Hall elements 11 and 12, and the output voltage E with respect to the magnetic flux densities B11 and B12.
It decides 11 and E12.

The output voltage E12 of the Hall element 12 is

[0072]

[Equation 14] E12 = G * B12 = G * [beta] 1 * [Phi] 1 * (1- | [theta] 1 // 90 [deg.]).

As a result, the output voltage E11 of the Hall element 11
From the equation (12), there is a proportional relationship with a positive inclination with respect to the rotation angle θ1, and the output voltage E increases as the rotation angle θ1 increases.
11 also increases. That is, when the rotation angle θ1 is 0 °, the magnetic pole pieces 5 and 5 do not face the arcuate surface portions 4A and 4B of the magnet 4, so that the output voltage E11 is approximately 0 V (volt). When the magnet 4 is rotated clockwise from this position, the magnetic pole pieces 5, 5 and the arc surface 4 of the magnet 4 are rotated.
Since the facing area with A and 4B increases, the output voltage E11 also increases, and becomes the maximum voltage value when the rotation angle θ1 is 90 °.

On the other hand, the output voltage E12 of the Hall element 12 is in a proportional relationship with a negative inclination when the rotation angle θ1 is between 0 ° and 90 ° from the equation (14), and as the rotation angle θ1 increases. As a result, the output voltage E12 decreases. That is, when the rotation angle θ1 is 0 °, the pole piece 6 on one side and the arc surface 4A of the magnet 4 are
Are opposed to each other, and the pole piece 6 on the other side and the arcuate surface 4B are opposed to each other over the entire outer peripheral surface, so that the output voltage E12 has a positive maximum voltage value. When the magnet 4 is rotated clockwise from this position, the magnetic pole pieces 6 and 6 and the magnet 4 are rotated.
Since the facing area of the circular arc surface portions 4A and 4B is reduced, the voltage value of the output voltage E12 also decreases in proportion to the facing area,
When the rotation angle θ1 is 90 °, the output voltage E12 is almost 0V (volt).

However, the distance a between the magnetic pole pieces 5 and 6 is a.
When 1 is reduced as described above, the arrow C shown in FIG.
A leakage flux in the direction is likely to occur, the output voltages E11 and E12 do not have a proportional relationship with the rotation angle θ1 as shown in FIG. 10, and the rotation angle θ1 is 0 ° as shown by the characteristic line 26. The output voltage E11 decreases with a relatively large slope as the rotation angle θ1 approaches 90 °, and the increase (slope) of the output voltage E11 is suppressed as the rotation angle θ1 approaches 90 °. This tendency also applies to the output voltage E12 of the characteristic line 27 shown by the dotted line in FIG.

That is, as in the comparative example shown in FIG. 7, the separation dimension a1 between the magnetic pole piece portions 5 and 6 is made sufficiently small, and the angle θm1 of the arc surface portion 4A of the magnet 4 and each of the first and the second. When the angle θy1 extending in the circumferential direction of the magnetic pole pieces 5 and 6 is set to an angle close to 90 °, each of the first and second magnetic poles is caused by the leakage magnetic flux in the C direction shown in FIG. Hall element 11, 12
The output voltages E11 and E12 from the characteristic curves 2 shown in FIG.
6 and 27, and the operation signal Sx1 at this time
As shown by the characteristic line 28 in FIG. 11, the characteristic does not have a linear characteristic with respect to the rotation angle θ1, and a large deviation occurs from the linear characteristic line 29.

Therefore, in the present embodiment, the angle θm1 of the arc surface 4A of the magnet 4 is smaller than the angle (θy1 + 2θa1) between the magnetic pole pieces 6, 6 (5, 5), and preferably the angle θ.
Angle that sums y1 and angle θa1 (θy1 + θa1 → 90 °)
The angle θy1 is smaller than (θm1 <θy1 + θa1) and smaller than the angle θm1 of the arc surface 4A of the magnet 4 (θy1 <θm1).

As a result, the rotation angle θ1 is 0 ° or 90 °.
At this time, between the second magnetic pole piece 6 or the first magnetic pole piece 5 facing the parallel surface portions 4C and 4D of the magnet 4 and the magnet, the leakage magnetic flux in the direction of arrow C illustrated in FIG. It is possible to prevent the occurrence of such a phenomenon, and it is possible to greatly reduce the influence of this leakage magnetic flux.

Further, by making the gap G1 smaller than the separation dimension a1 between the magnetic pole piece portions 5 and 6 (G1 <a1), the permeance P11 on the first and second magnetic pole piece portions 5 and 6 sides is reduced. , P12, P13, P14 can be made relatively larger than the permeance PS1 due to the periphery of the first and second Hall elements 11, 12, respectively.
It is possible to reduce the influence of the permeance PS1 from the output voltages E11 and E12 of No. 2 and also reduce the influence of the leakage magnetic flux as described above.

As a result, the first and second Hall elements 1
The output voltages E11 and E12 from 1, 12 are as shown by characteristic lines 30 and 31 in FIG. 5, and the output voltage E11 of the Hall element 11 decreases with a large inclination as the rotation angle θ1 approaches 0 °, for example. Similarly, as the rotation angle θ1 approaches 90 °, the output voltage E12 of the hall element 12 is similarly increased.
Does not decrease with a large slope. Further, the calculation signal Sx1 at this time has a linear characteristic proportional to the rotation angle θ1, as indicated by a characteristic line 32 in FIG.

Thus, according to this embodiment, the shaft 3 rotatably provided on the throttle body 2, the magnet 4 fixed to the shaft 3, and the magnet 4 are arranged so as to surround the magnet 4. The first magnetic pole piece portions 5 and 5, the second magnetic pole piece portions 6 and 6, the magnetic path forming portions 7 and 8 whose proximal ends are connected to the magnetic pole piece portions 5 and 5, and the magnetic pole piece portions 6 and 6. 6, the magnetic path forming portions 9 and 10 of which the base end side is connected, the first Hall element 11 provided between the front end portions 7A and 8A of the magnetic path forming portions 7 and 8, and the magnetic pole forming portions 9 and 10. Of the tip 9A, 10A
The second Hall element 12 provided between the first and second Hall elements
The arithmetic circuit 19 which outputs the detection signal So1 corresponding to the rotation angle θ1 based on the output voltages E11 and E12 from the Hall elements 11 and 12 has the following effects.

That is, the first and second magnetic pole piece portions 5, 6 and the like do not come into contact with the rotating shaft 3 and the magnet 4 without adding extra sliding resistance (load etc.) to the shaft 3. The rotation angle can be detected, the durability can be surely improved by the non-contact structure, and the output voltages E11, E12 from the first and second Hall elements 11, 12 are instantaneously changed. High reliability can be obtained without interruption.

Further, as shown in the equation (2), the rotation angle θ1
Since the detection signal So1 corresponding to is output from the arithmetic circuit 19, the magnetomotive force F of the magnet 4 is generated by the detection signal So1.
1. It is possible to accurately detect the rotation angle θ1 without depending on the temperature characteristics of the element sensitivity G, deterioration with time, and the like.

Then, the magnetic flux generated by the magnet 4 is transferred from the first magnetic pole piece parts 5, 5 to the first magnetic path forming parts 7, 8 in the first direction.
The first Hall element 11 can be efficiently guided to the second Hall element 12 from the second magnetic pole piece portions 6 and 6 through the magnetic path forming sections 9 and 10. The output voltage E11 corresponding to the magnetic flux Φ11 generated by the magnet 4 generated between the magnetic pole piece portions 5 and 5 can be output, and the second Hall element 12 can generate the magnetic flux generated by the magnet 4 between the second magnetic pole piece portions 6 and 6. The output voltage E12 corresponding to Φ12 can be output, and the levels of the output voltages E11 and E12 output from the first and second Hall elements 11 and 12 can be greatly changed according to the rotation angle θ1 of the magnet 4. .

Further, the magnetic flux generated by the magnet 4 can be efficiently guided to the first and second Hall elements 11 and 12 by the respective magnetic path forming sections 7, 8, 9 and 10, and each Hall element 11, The degree of freedom in mounting 12 can be increased. Then, the first and second Hall elements 11 and 12 can be arranged close to each other, the conditions such as the ambient temperature can be the same, and the one-chip integrally formed from the same semiconductor substrate. It becomes possible to use the Hall elements 11 and 12.

On the other hand, since the first and second magnetic pole piece portions 5 and 6 have a divided cylindrical shape surrounding the magnet 4 and are arranged on a concentric circle centered on the shaft 3, each arc surface portion of the magnet 4 is arranged. The distance when 4A and 4B face the magnetic pole piece portions 5 and 6 can be kept constant. As a result, a magnetic flux Φ11 proportional to the area where the first magnetic pole piece portions 5 and 5 and the arcuate surface portions 4A and 4B of the magnet 4 face each other can be guided from the first magnetic pole piece portions 5 and 5. The output voltage E proportional to the rotation angle θ1 from the Hall element 11 provided between the tip portions 7A and 8A of the magnetic path forming portions 7 and 8 connected to the portions 5 and 5.
You can get 11. Further, the magnetic flux Φ12 proportional to the area where the second magnetic pole piece portions 6 and 6 and the arcuate surface portions 4A and 4B of the magnet 4 face each other can be guided from the second magnetic pole piece portions 6 and 6, and the magnetic pole piece portions 6 and 6 can be guided. 6, a magnetic path forming portion 9 connected to 6,
Hall element 1 provided between the tip portions 9A and 10A of 10
The output voltage E12 corresponding to the rotation angle θ1 can be obtained from 2.

Further, since the magnet 4 and the magnetic pole pieces 5 and 6 can be compactly arranged on the concentric circle, the turning angle detecting device can be downsized and the turning shaft 3 can be used.
Since only the magnet 4 needs to be fixed, it is possible to greatly simplify the work of assembling and mounting the rotation angle detecting device.

Further, the gap G1 is set to the magnetic pole piece parts 5, 6
It is smaller than the separation dimension a1 (angle θa1) between (G1 <a
1) Therefore, the permeances P11, P12, P13, P14 on the first and second pole piece parts 5, 6 side are more relative than the permeance PS1 around the first and second hall elements 11, 12. The output voltage E11, E12 of each of the first and second Hall elements 11, 12 can be made larger than the permeance PS1.
The effect of can be reduced.

Furthermore, the arc surface portion 4A of the magnet 4 is
Angle θm1 of the magnetic pole pieces 5, 5 (6, 6) (θy1
Less than + 2θa1), preferably angle θy1 and angle θy
The angle θy1 is formed to be smaller than the total angle (θy1 + θa1 → 90 °) (θm1 <θy1 + θa1).
Is smaller than the angle θm1 of the arc surface 4A of the magnet 4 (θy1 <θm1), the rotation angle θ1 is 0 °.
Or at 90 °, the parallel surface portion 4C of the magnet 4
It is possible to prevent a leakage magnetic flux or the like from being generated between the magnet 4 and the second magnetic pole piece 6 or the first magnetic pole piece 5 that faces 4D, and it is possible to significantly reduce the influence of the leakage magnetic flux.

Next, FIGS. 12 to 15 show a second embodiment of the present invention.
In this embodiment, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted. However, the feature of this embodiment resides in that the rotation angle detecting device is configured by using three magnetic pole pieces.

In FIG. 12, reference numeral 41 denotes a magnet disposed in the cylindrical portion 1A of the casing 1. The magnet 41 is attached to the tip side of the shaft 3 by caulking or the like, and projects from the shaft 3 in the radial direction. . Here, the magnet 41 has arcuate surface portions 41A, 4 on both end sides in the longitudinal direction.
1B, and both side surfaces in the width direction are parallel surface portions 41C and 41D
It has become.

The arc surface 41 of the magnet 41
A and 41B extend in the circumferential direction with a constant curvature over a range of an angle .theta.m2 slightly smaller than 90.degree. About the shaft 3, and magnetic poles (N pole, S pole) are formed on the end face side. Further, the shaft 3 is provided at the center of the magnet 41.
A through hole 41E extending in the axial direction of the
1E has a shape similar to that of the magnet 41, and has a shaft 3
On the other hand, the magnet 41 is fixed so as not to rotate.

Reference numeral 42 designates a first magnetic pole piece portion embedded in the cylindrical portion 1A of the casing 1, and the first magnetic pole piece portion 42 is shown in FIG.
2, the second and third magnetic pole piece portions 43, which will be described later,
Together with 44, the magnet 41 is in the shape of a divided cylinder that surrounds the magnet 41 in an annular shape. Then, the pole piece portion 42 is the magnet 4
1 N arc side arc surface 41A and a constant gap G2
With the shaft 3 as the center so that the angle θ
It extends in the circumferential direction over a range of an angle θy2 smaller than m2. Here, each magnetic pole piece portion 43 in which the magnetic pole piece portion 42 is located,
The angle (θy2 + 2θa2) between 44 is larger than the angle θm2 of the arc surface portions 41A and 41B of the magnet 41 (θm2 <
θy2 + 2θa2). in this case,
The angle θy2 at which the magnetic pole piece portion 42 extends in the circumferential direction and each magnetic pole piece portion 4
The sum of the angle θa2 at which the magnets 2, 43, and 44 are separated is the angle θm2 of the arc surface portions 41A and 41B of the magnet 41.
It is desirable to form larger than (θm2 <θy2 + θa2). The magnetic pole piece portion 42 guides the magnetic flux generated by the magnet 41 to the first Hall element 48 via the first magnetic path forming portion 45 described later.

43 is a gap G from the first pole piece portion 42.
A second magnetic pole piece portion embedded in the cylindrical portion 1A of the casing 1 with a separation dimension a2 (angle θa2) larger than 2 is shown, and the second magnetic pole piece portion 43 is the same as the first magnetic pole piece portion 42. Similarly, it extends in the circumferential direction over the range of an angle θy2 smaller than the angle θm2 around the shaft 3 so as to face the arc surface 41A of the magnet 41 with a constant gap G2. The magnetic pole piece portion 43 guides the magnetic flux generated by the magnet 41 to the second Hall element 49 via the second magnetic path forming portion 46 described later.

44 is the first and second magnetic pole piece portions 42, 4
3 shows a third magnetic pole piece provided with a separation dimension a2 larger than the gap G2 from the third magnetic pole piece 4;
Reference numeral 4 is embedded in the cylindrical portion 1A of the casing 1 and extends in the circumferential direction over a range of about 180 ° so as to always face the arc surface portion 41B on the S pole side of the magnet 41 at a constant interval. There is. Then, the magnetic pole piece portion 44 causes the magnetic flux generated by the magnet 41 to pass through a third magnetic path forming portion 47 described later.
It is led to the first and second Hall elements 48 and 49 via.

Here, regarding the rotation angle θ 2 of the magnet 41 (shaft 3), the central portion of the arc surface portion 41A is the first and second portions.
The state facing the intermediate position between the magnetic pole piece portions 42 and 43 is set to the zero (θ2 = 0 °) position, and when the arc surface portion 41A of the magnet 41 rotates toward the first magnetic pole piece portion 42,
The arc surface portion 41 of the magnet 41 is provided on the second magnetic pole piece portion 43 side.
The negative direction is when A rotates.

Reference numeral 45 denotes a first magnetic path forming portion whose base end side is connected to the first magnetic pole piece portion 42 and whose front end side protrudes into the concave portion 1C of the casing 1. The tip side covers the upper side of the first Hall element 48 with a gap therebetween and faces the tip side of the third magnetic path forming portion 47 located below the Hall element 48.

Reference numeral 46 denotes a second magnetic path forming portion, the base end side of which is connected to the second magnetic pole piece portion 43, and the tip end side of which projects into the concave portion 1C of the casing 1. The tip side covers the upper side of the second Hall element 49 via a gap and faces the tip side of the third magnetic path forming portion 49 located below the Hall element 49.

Here, as shown in FIG. 14, the magnetic path forming portions 45 and 46 have their tip portions 45A and 46A opposed to a tip portion 47A of a magnetic path forming portion 47, which will be described later, with areas equal to each other, and the clearance dimension therebetween. b2 is constructed to have a constant size.

Reference numeral 47 denotes a third magnetic path forming portion whose base end side is connected to the third magnetic pole piece portion 44 and whose front end side protrudes into the concave portion 1C of the casing 1. The third magnetic path forming portion 47 is The circuit board 1 whose tip side is above the partition wall portion 1B of the casing 1 will be described later.
3 is arranged so as to extend along the back surface. As shown in FIG. 14, the tip 47A of the magnetic path forming portion 47 is arranged so as to face the tip 45A, 46A of the magnetic path forming portions 45, 46, and Hall elements 48, 49 and the like are provided between the two. It has been inserted.

Reference numerals 48 and 49 denote Hall elements provided on the circuit board 13 as first and second signal output means,
The first and second Hall elements 48 and 49 are one chip (one chip) on the circuit board 13 so as to be in parallel relationship with each other.
Are arranged. Then, the first Hall element 4
As shown in FIG. 14, 8 is located between the tip portion 45A of the magnetic path forming portion 45 and the tip portion 47A of the magnetic path forming portion 47, and outputs the first signal proportional to the magnetic flux density between them as the output voltage E21. Is output as. On the other hand, the second Hall element 49 is located between the tip portion 46A of the magnetic path forming portion 46 and the tip portion 47A of the magnetic path forming portion 47, and outputs a second signal proportional to the magnetic flux density between them. The voltage is output as voltage E22.

Reference numeral 50 denotes an output voltage E2 which is mounted on the circuit board 13 and is output from the first and second Hall elements 48 and 49.
1 and E22 shows an arithmetic circuit as an arithmetic means for arithmetically outputting the detection signal So2 corresponding to the rotation angle.
2, a divider 53, an amplifier 54 and the like.

51 is the first and second Hall elements 48, 49.
An adder for adding the output voltages E21 and E22 output from
52 is a subtractor for subtracting the output voltages E21, E22 output from the first and second Hall elements 48, 49, 53 is a divider for taking the ratio of the output of the adder 51 and the output of the subtractor 52, 5
Reference numeral 4 denotes an amplifier that amplifies the output of the divider 53.
The amplifier 54 is electrically connected to each terminal pin 14 and outputs the detection signal So2 corresponding to the rotation angle to the outside via each terminal pin 14.

Reference numeral 55 is a reference voltage generator for determining an offset level with respect to the output of the divider 53, and reference numeral 56 is an adjustment signal generator for correcting (correcting) the output signal of the amplifier 54 to adjust the output characteristic of the signal to a linear characteristic. Showing the vessel.

The rotation angle detecting device according to the present embodiment has the above-mentioned structure, and its operation will be described below with reference to FIGS. 12 to 15.

Even in this case, in order to simplify the explanation of the principle of detecting the rotation angle, the arc surface 41A of the magnet 41 is described.
And the angle θy2 between the first and second magnetic pole piece portions 42 and 43 are set to about 90 °, and the third magnetic pole piece portion 4
The angle of 4 is set to about 180 °, and each pole piece 42, 4
Assuming that the distance a2 (angle θa2) between 3, 44 is extremely small, the following equations 15 to 24 are derived.

First, as shown in FIG. 14, the arcuate surface portion 41A of the magnet 41 is also moved to the first and second positions as the shaft 3 rotates.
± 4 from the position where the magnetic pole pieces 42 and 43 of the
It rotates in the circumferential direction with a rotation angle θ2 within a range of 5 °. At this time, the arcuate surface portion 41A of the magnet 41 faces the first magnetic pole piece portion 42 over the range of the angle θ21, and faces the second magnetic pole piece portion 43 over the range of the angle θ22. On the other hand, the arc surface portion 41B of the magnet 41 is the third
The magnetic pole piece portion 44 of No. 2 continues to face. And the magnet 4
The magnetic flux generated by No. 1 is guided from the first and third magnetic pole piece portions 42, 44 to the first Hall element 48 through the first and third magnetic path forming portions 45, 47, while the second, third The magnetic pole pieces 43 and 44 are guided to the second Hall element 49 through the second and third magnetic path forming portions 46 and 47.

At this time, the magnet 41 and the magnetic pole piece 4
Reference numerals 2, 43 and 44 denote magnets 41, magnetic pole piece portions 42 and 44 and magnetic path forming portions 45 and 4 as shown in FIGS.
7 to form a first magnetic circuit, and the magnet 41, the magnetic pole piece portions 43 and 44, and the magnetic path forming portions 46 and 47 to the second magnetic circuit.
And the two magnetic circuits are magnetically connected in parallel.

Here, the arc surface portion 41A of the magnet 41 is
If the reciprocal of the magnetic resistance generated between the first and second magnetic pole pieces 42 and 43 is permeance P21 and P22, these permeances P21 and P22 are the arc surface 41A of the magnet 41 and the first and second magnetic poles. Is substantially proportional to the area of the magnetic pole pieces 42 and 43 facing each other,

[0110]

P21 = α2 × μ0 × θ21 = α2 × μ0 × (45 ° + θ)

[0111]

P22 = α2 × μ0 × θ22 = α2 × μ0 × (45 ° −θ)

Here, the constant α 2 is a constant value determined in advance by the axial dimension of the magnet 41, the axial dimension of the magnetic pole piece portions 42 and 43, the distance between the magnet 41 and the magnetic pole piece portions 42 and 43, and the like. And the magnetic permeability μ 0 indicates the magnetic permeability in vacuum.

If the reciprocal of the magnetic resistance generated between the arc surface 41B of the magnet 41 and the third magnetic pole piece 44 is defined as permeance P23, then this permeance P23 is the arc surface 41B of the magnet 41 and the third magnetic pole. The magnet 44 always faces the one piece 44 at 90 °,
Since the arcuate surface portion 41A of the above always faces the first magnetic pole piece portion 42 and the second magnetic pole piece portion 43 as a whole at 90 °,

[0114]

The relationship of P23 = α2 × μ0 × 90 ° = P21 + P22 is established.

At this time, the first and second Hall elements 48,
If the reciprocal of the magnetic resistance generated by the circumference of 49 is permeance PS2, this permeance PS2 becomes a value sufficiently smaller than the permeance P21, P22 on the first and second magnetic pole piece portions 42, 43 side. The permeance PS2 is a value that can be substantially ignored.

Therefore, the total magnetic flux Φ2 generated by the magnetomotive force F2 of the magnet 41 and passing through the first and second magnetic circuits is

[0117]

(Equation 18) The relationship is always constant.

Further, the magnetic flux Φ passing through the magnetic pole piece portions 42 and 43.
21 and Φ22 have a relationship of Φ21: Φ22 = P21: P22, and

[0119]

[Equation 19]

[0120]

(Equation 20) Is required.

Here, the tip end portion 4 of the magnetic path forming portions 45 and 46
Since 5A and 46A face the tip portion 47A of the magnetic path forming portion 47 with an area equal to each other, if the constant due to this facing area is β, the magnetic flux passing through the first and second Hall elements 48 and 49. The densities B21 and B22 are

[0122]

[Expression 21] B21 = β × Φ2

[0123]

[Equation 22] B22 = β × Φ2

The hall elements 48 and 49 have the same characteristics, and the output voltages E21 and E22 of the hall elements 48 and 49 are the same.
Is proportional to the magnetic flux densities B21 and B22,

[0125]

E21 = G × B21 = G × β × Φ2 × (0.5 + θ2 / 90 °)

[0126]

[Equation 24] E22 = G × B22 = G × β × Φ2 × (0.5−θ2 / 90 °). Here, G is the element sensitivity of the Hall elements 48 and 49, and is the output voltage E with respect to the magnetic flux densities B21 and B22.
21 and E22 are decided.

Here, the output voltages E21, E22 are changed by the influence when the element sensitivity G of the Hall elements 48, 49 changes due to the ambient temperature or the like. The total magnetic flux Φ2 is the magnetomotive force F2 of the magnet 41.
Therefore, the output voltages E21 and E22 also change due to the magnetomotive force F2 of the magnet 41 and the like.

Therefore, the output voltages E21 and E22 are input to the arithmetic circuit 50, and the arithmetic circuit 50 performs the arithmetic operation represented by the following equation (25).

[0129]

(Equation 25) Here, the subtracter 52 of the arithmetic circuit 50 outputs the output voltages E21, E
The subtraction value (E21-E22) is obtained by subtracting 22,
The adder 51 adds the output voltages E21 and E22 to obtain an added value (E21 + E22). Then, the divider 53 divides the added value (E21 + E22) and the subtracted value (E21-E22) to perform the operation according to the equation (25).

Further, the reference voltage generator 55 inputs the reference voltage to the divider 53, the amplifier 54 amplifies the operation signal Sx2 output from the divider 53, and the adjustment signal generator 56 adjusts the amplifier 54. By inputting the signal, the minute fluctuation of the detection signal So2 output from the amplifier 54 is corrected.

That is, the detection signal So2 is based on the operation signal Sx2,

[0132]

(Equation 26) Is required.

Here, Vo is a constant voltage value (for example, 2.
5V), and the constant k indicates a constant amplification factor.

As a result, the minimum value (Vo-k) is obtained when the rotation angle θ2 is -45 °, the maximum value (Vo + k) is obtained when the rotation angle θ2 is 45 °, and the detection signal So2 is changed. θ2
It is determined by only the magnetomotive force F2 of the magnet 41 and the element sensitivity G of the Hall elements 48 and 49.

By the way, as described above, the magnetic pole piece portions 42, 4
When the distance a2 between 3 and 44 is made sufficiently small, the angle θm2 of the arc surface 41A of the magnet 41 and the angle θy2 of the first and second magnetic pole pieces 42 and 43 extending in the circumferential direction are set. When the angle is close to 90 °, the leakage magnetic flux is generated and the rotation angle θ2 is -4 as in the first embodiment.
The output voltage E21 of the first Hall element 48 when it is 5 ° decreases, and the output voltage E22 of the second Hall element 49 when the rotation angle θ2 is + 45 ° decreases.

Further, the first and second Hall elements 48, 49
Due to the influence of the permeance PS2 caused by, a large error occurs in the ratio of the output voltages E21, E22 of the Hall elements 48, 49 when the rotation angle θ2 is around ± 22.5 °.

Therefore, when the distance a2 between the pole piece portions 42, 43 and 44 is made sufficiently small, the output voltages E21 and E22 from the first and second Hall elements 48 and 49 have linear characteristics. In addition, the operation signal Sx2 at this time cannot obtain a linear characteristic with respect to the rotation angle θ2.

Therefore, in this embodiment, the angle θm2 of the arc surface 41A of the magnet 41 is set to the angle θy2 of the first magnetic pole piece 42 and the angle θa2 of the magnetic pole pieces 42, 43, 44 which are separated from each other. Is smaller than the sum (θy2 + θa2 → 90 °) (θm2 <θy2 + θa2), and each pole piece 4
The angle θy2 of 2, 43 is the arc surface 41A of the magnet 41.
Is smaller than the angle θm2 (θy2 <θm2), the second and third magnetic pole piece portions facing the parallel surface portions 41C and 41D of the magnet 41 when the rotation angle θ2 is −45 ° or 45 °. The leakage flux passing through 43, 44 or the first and third magnetic pole piece portions 42, 44 is reduced.

Further, by making the gap G1 smaller than the separation dimension a1 between the magnetic pole piece portions 5 and 6 (G2 <a2), the permeance P21 on the first and second magnetic pole piece portions 5 and 6 side is reduced. , P22, P23 are the first and second Hall elements 48,
The permeance PS2 by 49 can be made relatively larger, the influence of the permeance PS2 from the output voltages E21, E22 of the Hall elements 48, 49 can be reduced, and the leakage magnetic flux can be reduced. The characteristics are almost proportional to θ 2.

Thus, according to this embodiment, the same effect as that of the first embodiment can be obtained, but in particular, in this embodiment, there is a proportional relationship with the rotation angle θ 2 as shown in the equation (26). Since a certain detection signal So2 can be output from the arithmetic circuit 50,
With this detection signal So2, the magnetomotive force F2 of the magnet 41,
It is possible to accurately detect the rotation angle θ2 without depending on the temperature characteristics of the element sensitivity G, deterioration with time, and the like.

Further, the gap G2 is set to the magnetic pole piece portions 42,
It is smaller than the separation dimension a2 between 43 and 44 (G2 <a2
), The first, second, and third magnetic pole piece parts 42, 4
The permeances P21, P22, P23 on the 3,44 side are
The permeance PS2 due to the periphery of the second Hall elements 48 and 49 can be made relatively larger, and the influence of the permeance PS2 from the output voltages E21 and E22 of the first and second Hall elements 48 and 49 can be reduced.

Furthermore, the arc surface portion 4 of the magnet 41
The angle θm2 of 1A is the sum of the angle θy2 of the first magnetic pole piece portion 42 and the angle θa2 which is the distance between the first, second and third magnetic pole piece portions 42, 43, 44 (θy2 + θa2 → 90 °). Smaller than (θm2 <θy2 + θa2) and the angle θy2 of the first magnetic pole piece 42 is set to the arc surface 41A of the magnet 41.
Is smaller than the angle θm2 (θy2 <θm2), the second and third magnetic pole piece portions 43 facing the parallel surface portions 41C and 41D of the magnet 41 when the rotation angle θ2 is −45 ° or 45 °. , 44 or the first and third magnetic pole piece portions 4
It is possible to reduce the leakage magnetic flux passing through 2, 44 in the circumferential direction.

Next, FIG. 16 shows a third embodiment of the present invention. In this embodiment, the same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. To do. However, the feature of this embodiment is that the magnet 61 fixed to the shaft 3 and the like has a pair of fan-shaped magnetic pole portions 61.
It is composed of A and 61A and a rod-shaped connecting portion 61B for connecting the magnetic pole portions 61A.

Although the magnet 61 is formed in substantially the same manner as the magnet 4 described in the first embodiment, each magnetic pole portion 61A of the magnet 61 has a fan shape over a range of an angle θm1 from the center. With eggplant, each N
It is formed as a pole and an S pole. Also, the magnet 61
A through hole 61C is provided in the central portion of the connecting portion 61B in the axial direction of the shaft 3, and the shaft 3 is fixed to the through hole 61C in a rotation stop state.

Thus, in this embodiment having the above-mentioned structure, the same effect as that of the first embodiment can be obtained. In particular, however, in this embodiment, the magnet 61 is formed into a fan-shaped magnetic pole portion 61A and a rod shape. Since it is formed from the connecting portion 61B of
The magnetic flux generated from the magnet 61 can be spread in a fan shape over the angle θm1 from each magnetic pole portion 61A. Therefore, even when the rotation angle θ1 is in the vicinity of ± θm1, the first and second magnetic pole pieces 5 and 6 and the magnetic pole portions 61A of the magnet 61 are formed.
A magnetic flux corresponding to the opposing area with respect to can be accurately guided from the magnet 61 to the first and second Hall elements 11 and 12, and an accurate rotation angle θ1 can be detected over the entire range of rotation. .

In each of the above embodiments, the output voltages E11, E of the first and second Hall elements 11, 12 (48, 49) are used.
An arithmetic circuit 50 for arithmetically outputting a detection signal So1 (So2) corresponding to the rotation angle θ1 (θ2) based on 12 (E21, E22).
Is provided inside the casing 1, but the present invention is not limited to this, and the first and second Hall elements 11 and 12 are not limited to this.
(48,49) output voltage E11, E12 (E21, E2
2) is output from each terminal pin 14 and is output to the casing 1
Detection signal So1 (So2) by an arithmetic circuit etc. provided outside
May be calculated and output.

Further, in each of the above-mentioned embodiments, the magnet 4 (41, 61) is fixed to the shaft 3 serving as the rotating shaft and is rotated, but the present invention is not limited to this. For example, a magnet is fixedly installed on the casing side,
First, second magnetic pole piece portions 5, 6 side or first, second, third
The magnetic pole piece portions 42, 43, 44 may be configured to rotate about a rotation shaft or the like.

Further, in each of the above-mentioned embodiments, the first magnetic pole piece 5 (42), the second magnetic pole piece 6 (43) or the third magnetic pole piece 44 is provided over a predetermined angle range. Although the present invention is described as being formed so as to extend in the circumferential direction, the present invention is not limited to this, and the first and second magnetic pole piece portions or the third magnetic pole piece portions are provided.
The magnetic pole piece portions may be divided into small angle ranges, and each of them may be formed as two or more magnetic pole piece portions.

[0149]

As described above in detail, in the invention described in claim 1, the magnet having the arcuate surface portion and the magnet are arranged around the magnet so as to be opposed to the arcuate surface portion of the magnet. At least three or more magnetic pole piece portions extending at predetermined angles in the circumferential direction,
Rotating means for rotating either one of the magnetic pole pieces and the magnet to relatively rotate the magnetic pole pieces and the magnet, and the facing area of the arc surface of the magnet and the magnetic pole pieces. Signal output means for respectively outputting the first and second signals generated corresponding to the above, and the distance between the magnetic pole pieces is made larger than the gap between the magnet and the magnetic pole pieces. Therefore, the relative rotating pole pieces and the magnet can be held in a non-contact state, and the durability and reliability can be improved, and the facing area between the two pole pieces and the magnet can be set to the rotation angle. Can be adapted,
From the first and second signal output means, the first and the first corresponding to the rotation angle
The second signal can be output.

Further, the magnetic flux generated by the magnet can be efficiently guided to the first and second signal output means by each magnetic pole piece portion, and the degree of freedom in mounting the respective signal output means can be increased. Then, the first and second signal output means can be arranged close to each other, the conditions such as the ambient temperature can be made the same, and, for example, from the Hall element etc. integrally formed from the same semiconductor substrate. It is possible to form the first and second signal output means.

Further, since the gap between the magnet and each magnetic pole piece is formed smaller than the space between the magnetic pole pieces, the arc surface of the magnet can be brought closer to each magnetic pole piece and faces the arc surface of the magnet. It is possible to reliably guide the magnetic flux to each of the magnetic pole pieces, and it is possible to reduce the magnetic resistance of the magnetic pole pieces facing the arc surface of the magnet, and to reduce the influence of the magnetic resistance of the Hall element.

According to the second aspect of the present invention, the distance between the magnetic pole pieces is made larger than the gap between the magnet and the magnetic pole pieces, and the arc surface of the magnet is at least one of the magnetic pole pieces. Since it is configured to extend at a larger angle in the circumferential direction than the magnetic pole pieces, magnetic flux can be reliably guided to each magnetic pole piece facing the arc surface of the magnet, leakage flux can be reduced, and the The influence of resistance can be reduced, and a detection signal having a linear characteristic can be taken out.

On the other hand, in the invention described in claim 3, the rotating means relatively rotates the first and second magnetic pole pieces and the magnet, and the first and second signal outputting means cause the first and second magnetic pole pieces to rotate relative to each other.
The first and second signals generated corresponding to the facing areas of the second magnetic pole piece portions and the arcuate surface portions of the magnet are respectively output, and the distance between the magnetic pole piece portions is set to be the same as that of the magnet. Since the gap is larger than the gap with the magnetic pole piece, the first and second magnetic pole pieces that rotate relative to each other can be held in a non-contact state, and the first and second magnetic pole pieces can be held. The space between the magnet and the magnet can be kept constant, and the facing area between the magnet and the first and second magnetic pole pieces can be changed according to the rotation angle.

Further, the first signal output means can output a first signal corresponding to an area (magnetic field) facing the magnet between the first magnetic pole piece portions, and the second signal output means. The means can output the second signal corresponding to the area (magnetic field) facing the magnet between the second magnetic pole pieces, so that each of the first and second signal output means outputs the second signal. The signal level can be greatly changed according to the relative rotation of the magnet or the like.

Further, since the gap between the magnet and each magnetic pole piece is formed smaller than the distance between the magnetic pole pieces, the arc surface of the magnet can be brought closer to each magnetic pole piece and faces the arc surface of the magnet. It is possible to reliably guide the magnetic flux to each of the magnetic pole pieces, and it is possible to reduce the magnetic resistance of the magnetic pole pieces facing the arc surface of the magnet, and to reduce the influence of the magnetic resistance of the Hall element.

Further, in the invention according to claim 4, the arcuate surface portion of the magnet extends at a larger angle in the circumferential direction than at least one of the magnetic pole piece portions of the first and second magnetic pole piece portions. Since it is configured, the facing area with the magnet can be changed over the entire circumference of one of the magnetic pole pieces corresponding to the rotation angle, and the magnetic pole pieces facing the arc surface of the magnet can be securely attached. The magnetic flux can be guided to the circuit, the leakage magnetic flux can be reduced, and a detection signal having a linear characteristic can be taken out.

Further, in the invention according to claim 5, the arcuate surface portion of the magnet is arranged in the circumferential direction more than the angle between at least one of the magnetic pole piece portions among the first and second magnetic pole piece portions. Since the structure extends at a small angle, it is possible to prevent the leakage magnetic flux from being guided to the first and second magnetic pole piece portions, and it is possible to accurately detect the rotation angle.

Furthermore, in the invention described in claim 6,
Since it is configured to include a computing unit that computes and outputs a detection signal corresponding to the rotation angle of the rotation unit based on the first and second signals output from the first and second signal output units,
A signal component affected by the magnetomotive force of the magnet, temperature characteristics of element sensitivity, deterioration over time, and the like can be reliably canceled, and a rotation angle detection signal can be output with linear characteristics.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a rotation angle detection device according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken in the direction of arrows II-II in FIG.

FIG. 3 is a circuit block diagram showing an arithmetic circuit of the rotation angle detection device according to the first embodiment of the present invention.

FIG. 4 is an overall configuration diagram showing an arrangement relationship of a magnet, each magnetic pole piece portion, each hall element, and the like used in the rotation angle detection device according to the first embodiment of the present invention.

FIG. 5 is a characteristic diagram showing a relationship between an output voltage output from the first and second Hall elements used in the rotation angle detection device according to the first embodiment of the present invention and a rotation angle.

FIG. 6 is a characteristic diagram showing a relationship between a rotation angle and a calculation signal extracted from a calculation circuit used in the rotation angle detection device according to the first embodiment of the present invention.

FIG. 7 is an overall configuration diagram substantially similar to FIG. 4 shown as a comparative example for explaining the principle of detecting a rotation angle.

8 is an overall configuration diagram similar to FIG. 7, showing a state in which a magnet has rotated.

9 is a magnetic circuit diagram of the magnet, each pole piece, each hall element and the like according to the comparative example shown in FIG. 7. FIG.

10 is a characteristic diagram showing a relationship between an output voltage output from the first and second Hall elements according to the comparative example shown in FIG. 7 and a rotation angle.

FIG. 11 is a characteristic diagram showing a relationship between a rotation angle and a calculation signal extracted from a calculation circuit based on the output voltage of FIG.

FIG. 12 is an enlarged cross-sectional view similar to FIG. 2, showing a magnet, magnetic pole piece portions, etc. of a rotation angle detecting device according to a second embodiment of the present invention.

FIG. 13 is a circuit block diagram showing an arithmetic circuit of a rotation angle detection device according to a second embodiment of the present invention.

FIG. 14 is an overall configuration diagram showing an arrangement relationship of a magnet, each magnetic pole piece portion, each hall element and the like used in a rotation angle detection device according to a second embodiment of the present invention.

15 is a magnetic circuit diagram of the magnet shown in FIG. 13, each magnetic pole piece, each Hall element, and the like.

FIG. 16 is a plan view showing a magnet used in a rotation angle detecting device according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 3 Shaft (rotating shaft) 4, 41, 61 Magnet 5, 42 1st magnetic pole piece part 6, 43 2nd magnetic pole piece part 44 3rd magnetic pole piece part 11, 48 1st hall element (1st 1 signal output means) 12,49 second hall element (second signal output means) 19,50 arithmetic circuit (arithmetic means) E11, E21 output voltage (first signal) E12, E22 output voltage (second) Signal) So1, So2 detection signal θ1, θ2 rotation angle

Claims (6)

[Claims] 1. A magnet having an arc surface portion, and at least three or more magnets which are arranged apart from each other around the magnet so as to face the arc surface portion of the magnet and extend at predetermined angles in the circumferential direction. Magnetic pole piece portions, rotation means for rotating any one of the magnetic pole piece portions and the magnets to relatively rotate the magnetic pole piece portions and the magnets, arc surface portions of the magnets and the magnetic poles. Signal output means for respectively outputting a first signal and a second signal generated corresponding to the facing area with the piece, and the distance between the magnetic pole pieces is determined by the gap between the magnet and the magnetic pole piece. A rotation angle detection device configured to be larger. 2. A magnet having an arc surface portion, and at least three or more magnets which are arranged apart from each other around the magnet so as to face the arc surface portion of the magnet and extend at predetermined angles in the circumferential direction. Magnetic pole piece portions, rotation means for rotating any one of the magnetic pole piece portions and the magnets to relatively rotate the magnetic pole piece portions and the magnets, arc surface portions of the magnets and the magnetic poles. Signal output means for respectively outputting a first signal and a second signal generated corresponding to the facing area with the piece, and the distance between the magnetic pole pieces is determined by the gap between the magnet and the magnetic pole piece. The rotation angle detecting device is configured to be larger and the arc surface portion of the magnet extends at a larger angle in the circumferential direction than at least one of the magnetic pole piece portions. 3. A magnet having an arcuate surface portion, and a pair of first magnets which are arranged around the magnet so as to be opposed to the arcuate surface portion of the magnet and are spaced apart from each other, and which extend at a predetermined angle in the circumferential direction. Of magnetic pole pieces and a pair of second magnetic pole pieces arranged apart from the first magnetic pole pieces and between the first magnetic pole pieces and extending at a predetermined angle in the circumferential direction. And a rotating means for rotating either one of the first and second magnetic pole pieces and the magnet to relatively rotate the first and second magnetic pole pieces and the magnet. A first and a second signal output means for respectively outputting first and second signals generated corresponding to the facing areas of the first and second magnetic pole pieces and the arc surface of the magnet, The distance between the magnetic pole pieces is determined by the gap between the magnet and the magnetic pole pieces. A rotation angle detection device configured to be larger than the rotation angle. 4. The arc surface portion of the magnet is configured to extend at a larger angle in the circumferential direction than at least one magnetic pole piece portion of each of the first and second magnetic pole piece portions. Rotation angle detection device. 5. The arc surface portion of the magnet is configured to extend at a smaller angle in the circumferential direction than the angle between at least one of the first and second magnetic pole piece portions. Alternatively, the rotation angle detection device according to item 4. 6. A configuration comprising arithmetic means for arithmetically outputting a detection signal corresponding to a rotation angle of the rotation means based on the first and second signals output from the first and second signal output means. The rotation angle detecting device according to claim 1, 2, 3, 4 or 5.