JPH09311135A - Detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive and small-sized detector hardly influenced by external noise and capable of providing a signal having high detecting precision by signal processing the output of a Wheatstone bridge circuit formed of giant magnetic resistance(GMR) element. SOLUTION: In conformation to the change of magnetic field accompanying the rotation of a magnetic rotating body 2, the magnetic fields on the magnetosensitive surfaces of GMR elements 10A, 10D and 10B, 10C of a Wheatstone bridge circuit 11 are changed. This change corresponds to the magnetic field change 4 times one GMR element. The resistance value is changed in the same manner, the minimum position is reversed, and the middle point voltages of the connecting points 18, 19 of the circuit 11 are also changed in the same manner. Thus, the difference between the middle point voltages is amplified by a differential amplifying circuit 12, and the output 4 times one GMR element is provided in conformation to the magnetic field change of the rotating body 2. This output is processed by a comparing circuit 13 and a waveform shaping circuit 14, whereby an output of 0 or 1 with sharp leading and trailing can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detecting device for detecting a change in a magnetic field due to movement of a magnetic body moving body, and more particularly to a detecting device suitable for use in detecting rotation information of an internal combustion engine. is there.

[0002]

2. Description of the Related Art Generally, a magnetoresistive element (hereinafter referred to as an MR element) is a ferromagnetic material (for example, Ni-Fe, Ni-Co).
Etc.) An element whose resistance value changes depending on the angle formed by the magnetization direction of the thin film and the current direction. This MR element has a minimum resistance value when the current direction and the magnetization direction intersect at right angles,
The resistance value becomes maximum when the current direction and the magnetization direction are the same or completely opposite to each other at 0 degree. This change in resistance value is called the MR effect or MR change rate, and is generally Ni-F.
e is 2 to 3%, and Ni-Co is 5 to 6%.

FIG. 31 is a block diagram showing a conventional detecting device, FIG. 31 (a) is a side view thereof, and FIG. 31 (b) is a perspective view thereof. This detection device includes a rotating shaft 1, a magnetic rotating body 2 having at least one unevenness and rotating in synchronization with the rotating shaft 1, and a magnetic body rotating body 2 arranged with a predetermined gap. The MR element 3 has a magnetoresistive pattern 3a and a thin film surface (magnetically sensitive surface) 3b. Therefore, the magnetic field of the magnetic sensitive surface 3b of the MR element 3 changes as the magnetic body rotating body 2 rotates, and the resistance value of the magnetoresistive pattern 3a changes.

FIG. 32 schematically shows a circuit configuration of a conventional detecting device. The MR element 3 connected to a constant current source is
The voltage change signal S _VV corresponding to the unevenness of the magnetic body rotating body 2 is output. The waveform after the voltage change signal S _VV is amplified by a not-shown differential amplifier circuit or the like corresponds to the unevenness of the magnetic body rotating body 2 shown in FIG. Chain line a
Indicated by

[0005]

By the way, the conventional detecting device has various problems as described below. That is, the MR element used in the conventional detection device has a single-layer structure in which a ferromagnetic material is a thin film, and the resistance value changes depending on the angle formed by the direction of magnetization and the direction of current. That is, the magnetically sensitive surface has anisotropy. Therefore, the mounting position in the rotation axis direction is restricted in the positional relationship between the magnetic rotating body, the MR element, and the magnet. That is, in order to obtain a signal with high accuracy, it is necessary to align the centers of the magnetic rotating body, the MR element and the magnet. Also, since the MR effect is small,
Its output is also small, it is easily affected by noise,
The S / N ratio is also not good.

Further, if the gap between the magnetic rotating body and the MR element (hereinafter referred to as the gap) changes, the influence on the output is great, and it is necessary to manage the gap with high precision, and the shape cannot be made large. Further, the MR element is an element whose resistance value changes depending on the angle formed by the magnetization direction of the thin film and the current direction, and it is necessary to form a magnetic sensitive pattern of the thin film in order to detect changes in the magnetic field satisfactorily. Will be used. here,
The size of the MR element needs to be equal to or less than the size of the unevenness in order to detect the small unevenness of the magnetic rotating body. However, since the etching is limited, the detection accuracy is limited.

Further, since the conventional detecting device has a structure in which a magnet is arranged at a position where a magnetic field is applied to the MR element and the magnetic field change due to the rotation of the magnetic body rotating body having irregularities is detected by the MR element, To make it less susceptible to noise,
It is necessary to make the magnetic field change of the MR element part as large as possible. For that purpose, it is necessary to consider the arrangement of the MR element and the magnet and the concavo-convex shape of the magnetic body rotating body to be optimum.
In addition, if the gap between the magnetic rotating body, the MR element, and the magnet is increased, the amount of change in the magnetic field decreases, so it must be set within a certain range. Further, from the moment the power is supplied to the detection device, an accurate signal corresponding to the predetermined position of the magnetic body moving body, that is, the unevenness (rotation angle) of the magnetic body rotating body in this case (hereinafter referred to as power-on function) is obtained. Is difficult Also,
In order to obtain a signal with high accuracy, it is also necessary to match the centers of the magnetic rotating body and the MR element.

As described above, since the conventional detecting device is easily affected by the mounting accuracy and the magnetic field change is detected by using one MR element, when the magnetic field change of the MR element is small, the MR element is small. If the external noise is superposed on the detection device in that state, the output voltage change amount is small and the accurate signal may not be obtained. However, there is a problem in that a signal corresponding to the unevenness of the magnetic body rotating body cannot be accurately obtained and a power-on function cannot be obtained.

The present invention has been made in order to solve such a problem, and has less restrictions on the mounting accuracy of the sensor, is inexpensive, is small in size, is not easily affected by external noise, and has high detection accuracy. The purpose is to obtain a detection device from which a signal can be obtained. Another object of the present invention is to obtain a detection device that can obtain an accurate signal and a power-on function corresponding to a predetermined position (angle) of the magnetic body moving body.

[0010]

According to a first aspect of the present invention, there is provided a detecting device which is arranged with a predetermined gap between the magnetic field generating means for generating a magnetic field and the magnetic field generating means, and is generated by the magnetic field generating means. And a giant magnetoresistive element whose resistance value changes according to the magnetic field changed by the magnetic field change giving means.

According to a second aspect of the present invention, there is provided the detection device according to the first aspect of the invention, wherein the magnetic field change imparting means is constituted by a magnetic body moving body having at least one concavity and convexity.

According to a third aspect of the present invention, there is provided a detection apparatus according to the first aspect of the invention, wherein the magnetic field generating means and the magnetic field change imparting means are composed of a magnetic body moving body having at least one magnetic pole, and generate a magnetic field. And it was made to change.

According to a fourth aspect of the present invention, in the detection device according to the second or third aspect of the invention, the giant magnetoresistive element is enlarged in a direction orthogonal to the moving direction of the magnetic body moving body.

A detector according to a fifth aspect of the present invention is the detector according to any one of the first to fourth aspects of the invention, wherein a bridge circuit using a giant magnetoresistive element on at least one side and signal processing of the output of the bridge circuit are provided. And a signal processing means for performing the same.

According to a sixth aspect of the present invention, there is provided the detection device according to the fifth aspect, wherein two sides of the bridge circuit are formed of giant magnetoresistive elements, and the remaining two sides are formed of fixed resistors. is there.

According to a seventh aspect of the present invention, there is provided a detection device according to the sixth aspect, wherein one pair of opposite sides of the bridge circuit is composed of giant magnetoresistive elements, and the other pair of opposite sides is composed of fixed resistors. Is.

According to an eighth aspect of the present invention, in the detecting device according to any one of the first to seventh aspects, the magnetic body moving body is a rotating body that rotates in synchronization with a rotation axis.

According to a ninth aspect of the present invention, there is provided the detection device according to the eighth aspect, further comprising a detection device main body including at least a giant magnetoresistive element, the rotary body being mounted on a crankshaft or a camshaft of an internal combustion engine, The main body of the detection device is arranged in the vicinity of the internal combustion engine so that the rotating body faces the giant magnetoresistive element.

According to a tenth aspect of the present invention, there is provided a detection device,
In the invention of claim 9, the main body of the detection device is arranged in the rotation axis direction with respect to the rotating body.

The detection device according to the invention of claim 11 is
According to a tenth aspect of the invention, the main body of the detection device includes a housing in which at least a giant magnetoresistive element is incorporated, and the rotating body has a space formed on a side surface of the housing in which at least a peripheral portion of the rotating body has a giant magnetoresistive element. It is arranged so as to be opposed to.

[0021]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a detection apparatus according to the present invention. Embodiment 1. FIG. 1 is a block diagram showing a first embodiment of the present invention. FIG. 1 (a) is a side view thereof, and FIG. 1 (b).
Is a perspective view thereof. This detection device includes a rotating shaft 1 and a magnetic rotating body 2 as a magnetic field change imparting means that has at least one unevenness and rotates in synchronization with the rotating shaft 1.
A giant magnetoresistive element (hereinafter referred to as a GMR element) 10 arranged with a predetermined gap with the magnetic body rotating body 2;
The GMR element 10 comprises a magnetoresistive pattern 10a as a magnetically sensitive pattern and a thin film surface (magnetically sensitive surface) 10b.
And Therefore, the magnetic field of the magnetic sensitive surface 10b of the GMR element 10 changes as the magnetic body rotating body 2 rotates, and the resistance value of the magnetoresistive pattern 10a changes.

Here, the GMR element 10 is, for example, several angstroms to several tens of angstroms described in a paper entitled "Magnetoresistance Effect of Artificial Lattice" in Japanese Society of Applied Magnetics Vol.15, No.51991, p813-821. A laminated body in which magnetic layers and nonmagnetic layers having an angstrom thickness are alternately laminated, that is, a so-called artificial lattice film, (Fe / Cr) n, (Permalloy / Cu
/ Co / Cu) n and (Co / Cu) n are known,
This has a remarkably large MR effect (MR change rate) as compared with the above-mentioned MR element, and depends only on the relative angle of the magnetization directions of the adjacent magnetic layers, so that the direction of the external magnetic field depends on the current. On the other hand, it is a so-called in-plane magnetic sensitive element that can obtain the same change in resistance value regardless of any angle difference.

Therefore, in order to detect the change in the magnetic field, the GM
The R element 10 substantially forms a magnetically sensitive surface, and an electrode is formed at each end of the magnetically sensitive surface to form a bridge circuit. A constant voltage and a constant current are applied between two opposing electrodes of the bridge circuit. It is conceivable to connect a power source, convert the resistance value change of the GMR element 10 into a voltage change, and detect the magnetic field change acting on the GMR element 10.

FIG. 2 is a block diagram showing a detection device using the above-mentioned GMR element. This detecting device is arranged with a predetermined gap from the magnetic body rotating body 2 and uses a Wheatstone bridge circuit 11 using a GMR element to which a magnetic field is given by a magnet 4, and a differential amplifying the output of the Wheatstone bridge circuit 11. Amplifier circuit 12 and this differential amplifier circuit 1
A comparison circuit 13 that compares the output of 2 with a reference value and outputs a signal of "O" or "1", and the output of the comparison circuit 13 is further waveform-shaped and rises and falls "O" or The waveform shaping circuit 14 that outputs the signal of “1” to the output terminal 15 is provided. The differential amplifier circuit 12, the comparison circuit 13, and the waveform shaping circuit 14 constitute signal processing means.

FIG. 3 is a diagram showing an example of a concrete circuit configuration of the block diagram of FIG. Wheatstone bridge circuit 1
1 is, for example, GMR elements 10A, 10 on each side.
B, 10C and 10D, and GMR elements 10A and 1
Each one end of 0C is commonly connected, is connected to the power supply terminal Vcc through the connection point 16, each one end of GMR elements 10B and 10D is commonly connected, is grounded through the connection point 17, and GM.
The other ends of the R elements 10A and 10B are connected to the connection point 18, and the other ends of the GMR elements 10C and 10D are connected to the connection point 19.

The Wheatstone bridge circuit 11
18 is connected to the inverting input terminal of the amplifier 12a of the differential amplifier circuit 12 via a resistor, and the connection point 19 is connected to the non-inverting input terminal of the amplifier 12a via a resistor and further to the resistor. Is connected to the voltage dividing circuit that constitutes the reference power source. Further, the output terminal of the amplifier 12a is connected to the inverting input terminal of the comparison circuit 13, and the non-inverting input terminal of the comparison circuit 13 is connected to the voltage dividing circuit which constitutes the reference power source and outputs its own output through the resistor. Connected to the terminal.
The output side of the comparison circuit 13 is connected to the base of the transistor 14a of the waveform shaping circuit 14, its collector is connected to the output terminal 15 and also connected to the power supply terminal Vcc via a resistor, and its emitter is grounded. . FIG. 4 shows the GM that constitutes the Wheatstone bridge circuit 11 described above.
The R elements 10A, 10B, 10C and 10D are mounted on the substrate 20.
It is a figure which shows the state arrange | positioned on top typically.

Next, the operation will be described with reference to FIG. As the magnetic body rotating body 2 rotates, (a) of FIG.
Corresponding to the unevenness shown in FIG. 1, the same magnetic field change is applied to the GMR elements 10A and 10D that form the Wheatstone bridge circuit 11, and the GM is applied to the GMR elements 10B and 10C.
A magnetic field change different from that of the R elements 10A and 10D is given. As a result, as shown in FIG. 5B, the GMR elements 10A and 10D corresponding to the unevenness of the magnetic body rotating body 2 are formed.
And 10B, 10C, a magnetic field change occurs on the magnetic sensitive surfaces, that is, a magnetic field change that is substantially four times the magnetic field change of one GMR element can be obtained, and the resistance value of the GMR element also changes. The maximum and minimum positions of the resistance values of 10A, 10D and 10B, 10C are reversed, and the midpoint voltage of the connection points 18, 19 of the Wheatstone bridge circuit also changes similarly as shown in FIG. 5C. .

Then, the difference in the midpoint voltage is amplified by the differential amplifier circuit 12, and the output side thereof has the magnetic property shown in FIG. 5A as shown by the solid line b in FIG. 5D. Output corresponding to the unevenness of the rotating body 2, that is, substantially one GM
An output four times that of the R element can be obtained. This differential amplifier circuit 12
The output of is compared with the reference value by the comparison circuit 13 and converted into a signal of "O" or "1", and this signal is further waveform-shaped by the waveform shaping circuit 14 and, as a result, is output to its output side, that is, the output terminal 15. As shown in FIG. 5 (e), an output of "O" or "1" whose rising and falling are steep is obtained.

Thus, by amplifying the differential of the voltage change of the midpoint voltage, the magnetic field change of each GMR element can be effectively utilized, and the magnetic field change four times that of one GMR element can be obtained. That is, the bridge circuit configuration makes it possible to stably convert a magnetic field change due to the rotation of the magnetic body rotating body 2 into a large resistance value change amount. Therefore, the output of the differential amplifier circuit 12 also becomes large, and the margin for the judgment level for waveform shaping into the signal of “0” or “1” in the comparison circuit 13 increases, and it becomes strong against external noise. A stable signal can always be obtained. Although the WMR is used to form the Wheatstone bridge circuit, the same effect can be obtained with a similar bridge circuit structure.

As described above, in the present embodiment, the GMR element is used to form the Wheatstone bridge circuit, and
Since the magnetic sensitive surface of the R element has no anisotropy, that is, the GMR element depends only on the relative angle of the magnetization directions of the adjacent magnetic layers, the mounting accuracy (deviation) of the rotating body of the magnetic body in the rotation axis direction.
On the other hand, the restrictions are reduced, and it becomes possible to stably detect the change in the magnetic field due to the rotation of the rotating magnetic body. Therefore, the amount of resistance change of the GMR element is also stably increased, the output of the differential amplifier circuit is also increased, and the margin for the determination level when converting to the signal of “0” or “1” in the comparison circuit increases. It becomes stronger against external noise,
A stable signal can be obtained. Further, since the GMR element is in-plane magnetic sensing, it is not necessary to form a magnetic sensitive pattern by etching or the like unlike the MR element, the detection device can be downsized, the cost can be reduced, and small irregularities can be detected. Can be handled.

Embodiment 2 In the first embodiment, the GMR
Although the element 10 constitutes the Wheatstone bridge circuit to detect the change in the magnetic field due to the rotation of the magnetic body rotating body 2, in the present embodiment, the mounting accuracy (deviation) in the rotation axis direction is set.
GM in the direction of the rotation axis to further reduce the constraint
The shape of the R element is enlarged. 6 is a block diagram showing a second embodiment of the present invention. In the figure, the parts corresponding to those in FIG. This detection device is provided with a rotating shaft 1 and at least one unevenness, and a magnetic body rotating body 2 that rotates in synchronization with the rotating shaft 1 and a magnetic body rotating body 2 arranged with a predetermined gap. The GMR element 30 has a magnetic resistance pattern 30a and a thin film surface (magnetically sensitive surface) 30b.

Here, the magnetic sensitive surface 30b of the GMR element 30 is set to be large in the direction of the rotation axis 1 of the magnetic body rotating body 2. For example, the shape of the magnetic sensitive surface 30b is set to be larger than the thickness of the magnetic body rotating body 2 in the direction of the rotation axis 1. The shape of the magnet 31 is the same as that of the GMR element 30 as the shape of the GMR element 30 is increased. However, if the required magnetic field is obtained, it is similar to the magnet 4 of FIG. The shape may be small. Then, by rotating the magnetic body rotating body 2, GMR
The magnetic field of the magnetically sensitive surface 30b of the element 30 changes, and the resistance value of the magnetoresistive pattern 30a changes.

As described above, also in the present embodiment, the same effect as in the above-described first embodiment can be obtained, and further, in the present embodiment, the magnetic sensitive surface is defined by the thickness of the magnetic body rotating body in the rotation axis direction. By setting a large value, it is possible to reduce restrictions on the deviation of the mounting accuracy in the rotation axis direction and obtain a more stable signal.

Embodiment 3. FIG. 7 is a configuration diagram showing a third embodiment of the present invention. In the figure, the parts corresponding to those in FIG. Here, the magnet 4 shown in FIG. 4 is omitted for convenience of description. In the first embodiment, all four sides of the Wheatstone bridge circuit (FIG. 3) are made up of GMR elements. However, in the present embodiment, the GMR element and fixed resistors are combined to form a bridge circuit. is there. That is,
As shown in FIG. 7, a pair of opposite sides 10A and 1
0D is composed of a GMR element and is arranged on the substrate 20, and another set of opposite sides 10B and 10C not shown is composed of a fixed resistance having the same resistance value as that of the GMR element.

Next, the operation will be described with reference to FIG. By rotating the magnetic body rotating body 2, (a) of FIG.
Corresponding to the irregularities shown in FIG. 8, the same magnetic field changes are applied to the GMR elements 10A and 10D that form the Wheatstone bridge circuit 11, and as shown in (b) of FIG. As a result, a magnetic field change occurs on the magnetically sensitive surfaces of the GMR elements 10A and 10D, that is, substantially one G
A magnetic field change that is twice the magnetic field change of the MR element can be obtained, and its resistance value also changes, and the midpoint voltage of the connection points 18 and 19 of the Wheatstone bridge circuit is as shown in (c) of FIG. Change. In this case, the maximum and minimum positions of the voltage change at the connection points 18 and 19 are reversed.

Then, the difference between the midpoint voltages is amplified by the differential amplifier circuit 12, and the output side thereof has the magnetic body rotating body shown in FIG. 8A as shown in FIG. 8D. An output corresponding to the unevenness of 2 can be obtained, that is, substantially double the output of one GMR element. The output of the differential amplifier circuit 12 is compared with a reference value by a comparison circuit 13 to be "O" or "1".
Is converted into a signal of, and this signal is further waveform-shaped by the waveform shaping circuit 14, and as a result, its output side, that is, the output terminal 15
As shown in (e) of FIG. 8, a signal of "O" or "1" having a sharp rise and fall is obtained.

Thus, the magnetic field change of each GMR element can be effectively utilized by substantially amplifying the differential of the voltage change of the midpoint voltage, and the magnetic field change twice the magnetic field change of one GMR element can be obtained. . That is, the bridge circuit configuration makes it possible to stably convert a magnetic field change due to the rotation of the magnetic body rotating body 2 into a large resistance value change amount. Therefore,
The output of the differential amplifier circuit 12 also becomes large, and the margin for the judgment level when converting to the signal of “0” or “1” in the comparison circuit 13 increases, and it becomes strong against external noise and always A stable signal can be obtained. Although the WMR is used to form the Wheatstone bridge circuit, the same effect can be obtained with a similar bridge circuit structure.

As described above, also in this embodiment, the final output level is smaller than that in the first embodiment by the number of GMR elements, but other than that, the same effects as those in the first embodiment can be obtained. On the contrary, in the present embodiment, the GMR
Since the number of elements is small, the cost is low.

Fourth Embodiment 9 is a configuration diagram showing a fourth embodiment of the present invention. In the figure, the parts corresponding to those in FIG. Also here, the magnet 4 shown in FIG. 4 is omitted for convenience of description. In the third embodiment, a pair of opposite sides 10A and 10D forming the Wheatstone bridge circuit (FIG. 3) are GMR.
It is composed of elements, and the other pair of opposite sides 10B and 10C is GMR.
Although it has been described that the fixed resistance has the same resistance value as that of the element, in the present embodiment, one side of one set of the bridge circuit is configured by the GMR element, and the other side of the set is configured by the fixed resistance. That is, as shown in FIG. 9, one side 1 of the bridge circuit
0A and 10B are composed of GMR elements and arranged on the substrate 20, and the other sides (not shown) 10C and 10D are composed of fixed resistors having the same resistance value as that of the GMR elements.

Next, the operation will be described with reference to FIG. As the magnetic body rotating body 2 rotates, a magnetic field change is given to the GMR elements 10A and 10B forming the Wheatstone bridge circuit 11 corresponding to the unevenness shown in (a) of FIG. As shown in b), the GMR elements 10A, 10B are formed corresponding to the irregularities of the magnetic body rotating body 2.
A magnetic field change of opposite phase is generated on the magnetic sensitive surface of, that is, a magnetic field change that is substantially twice the magnetic field change of one GMR element can be obtained, and the resistance value of the magnetic field change also changes. The midpoint voltage of the connection points 18 and 19 of is changed as shown in FIG. Here, the voltage at the connection point 19 on the other side, which is composed of fixed resistors corresponding to the GMR elements 10C and 10D of the Wheatstone bridge circuit 11, is fixed so that the voltage becomes half the voltage change at the connection point 18. Adjust the resistance value.

Then, the difference in the midpoint voltage is amplified by the differential amplifier circuit 12, and the output side thereof is shown in FIG.
Output corresponding to the unevenness of the magnetic body rotating body 2 shown in, that is,
Substantially twice the output of one GMR element is obtained. The output of the differential amplifier circuit 12 is compared with a reference value by a comparison circuit 13 and converted into a signal of "O" or "1", and this signal is further waveform-shaped by a waveform shaping circuit 14. As a result,
At the output side, that is, the output terminal 15, a signal of "O" or "1" having a sharp rise and fall is obtained as shown in FIG. Thus, the magnetic field change of each GMR element can be effectively utilized by substantially amplifying the differential of the voltage change of the midpoint voltage, and the magnetic field change twice the magnetic field change of one GMR element can be obtained. That is, the bridge circuit configuration makes it possible to stably convert a magnetic field change due to the rotation of the magnetic body rotating body 2 into a large resistance value change amount.

Therefore, the output of the differential amplifier circuit 12 also becomes large, and the margin for the judgment level when converting to the signal of "0" or "1" in the comparison circuit 13 increases, so that the external noise is prevented. Becomes stronger, and a stable signal can always be obtained. It should be noted that although the GMR element is used to configure the Wheatstone bridge circuit here, the same effect can be obtained if the bridge circuit configuration is similar. As described above, also in this embodiment, the same effect as that of the third embodiment can be obtained.

Fifth Embodiment 11 is a configuration diagram showing a fifth embodiment of the present invention. In FIG. 1, FIG.
The same reference numerals are given to the portions corresponding to and will be described. This detection device is provided with a rotating shaft 1, a magnet 40 having at least one or more magnetic poles as a magnetic field generating unit, and a magnet 40 as a magnetic field changing unit that rotates in synchronization with the rotating shaft 1. It is composed of a body rotating body 41 and the GMR element 10 arranged with the magnetic body rotating body 41 with a predetermined gap. Therefore, when the magnetic body rotating body 41 rotates, the magnetic field of the magnetic sensitive surface 10b of the GMR element 10 changes due to the magnetic pole of the magnet 40 provided therein, and the resistance value of the magnetoresistive pattern 10a changes.

FIG. 12 is a block diagram showing a detecting device using the above-mentioned GMR element. This detection device is arranged with a predetermined gap from a magnetic body rotating body 41, and outputs a Wheatstone bridge circuit 11 using a GMR element to which a magnetic field is applied from a magnet 40 provided therein and an output of the Wheatstone bridge circuit 11. Differential amplifier circuit 12 for amplifying
A comparison circuit 13 that compares the output of the differential amplifier circuit 12 with a reference value and outputs a signal of “O” or “1”;
A waveform shaping circuit for further shaping the output of the comparison circuit 13 and outputting a signal of "O" or "1" having a sharp rise and fall to an output terminal 15; Note that, as an example of a concrete circuit configuration of the block diagram of FIG. 12, for example, a circuit as shown in FIG. 3 described above is used.

Next, in the case where a Wheatstone bridge circuit as described with reference to FIG. 3, for example, is constructed by the GMR element 10 arranged with a predetermined gap with the magnetic body rotating body 41 having such a magnet 40. The operation will be described with reference to FIG. When the magnetic body rotating body 41 rotates, the magnetic poles of the magnet 40 provided therein ((a) of FIG. 13) constitute the GMR element 10 that constitutes the Wheatstone bridge circuit 11, that is, 10A, 10B, 10C, 1
The magnetic field of the 0D magnetic sensitive surface changes and its resistance value changes, and accordingly, the output of the connection point 18 and the output of the connection point 19 also change according to the change of the magnetic field, and the output difference is differential. It is amplified by the amplifier circuit 12, and as a result, on the output side of the differential amplifier circuit 12, as shown in FIG. 13B, the magnetic pole of the magnet 40 (N in this case) included in the magnetic body rotating body 41 is used. very)
Is obtained.

The output of the differential amplifier circuit 12 is supplied to a comparator circuit 13 where it is compared with a reference value and converted into an "O" or "1" signal, which is further shaped by a waveform shaping circuit 14. As a result, the output side, that is, the output terminal 15, has a sharp "O" or "1" of rising or falling corresponding to the magnetic pole of the magnet 40 as shown in FIG. The signal is obtained.

As described above, in the present embodiment, the magnetic field of the GMR element is changed by the magnetic poles of the magnets provided in the magnetic body rotating body, and the magnetic body rotating from the moment the power is supplied to the detection device. The output corresponding to the magnetic poles of the magnet included in the body can be accurately obtained, and the power-on function can be stably obtained. In addition, by forming the Wheatstone bridge circuit with the GMR element, there is no anisotropy in the magnetic sensitive surface, and there is less restriction on the mounting accuracy (deviation) of the rotating body of the magnetic body in the direction of the rotation axis. The change in magnetic field due to rotation can be detected stably. Therefore,
Since the amount of change in resistance of the GMR element is also stably increased, the output of the differential amplifier circuit is also increased, and the difference in the comparison circuit is increased.
The margin with respect to the determination level when converting to a 0 "or" 1 "signal is increased, the resistance against external noise is increased, and a stable signal can be obtained.

Further, it is possible to accurately obtain the final output "0" or "1" corresponding to the magnetic pole of the magnet included in the magnetic body rotating body. Here, the output of the Wheatstone bridge circuit has a large change amount as compared with the conventional device, is less susceptible to external noise, and a signal corresponding to the magnetic pole can be stably obtained. Further, since the GMR element is in-plane magnetic sensing, it is not necessary to form a magnetic sensing pattern by etching or the like unlike the MR element, and the detection device can be downsized,
The cost can be reduced.

Embodiment 6 FIG. In the fifth embodiment described above, the magnetic rotating body is provided with the magnet having at least one magnetic pole, and the magnetic pole of the magnet is detected by the GMR element. The magnetic rotating body itself is configured and the magnetic poles of the magnet are configured (magnetized) so that necessary signals can be obtained. FIG. 14 is a configuration diagram showing Embodiment 6 of the present invention. In the figure,
The parts corresponding to those in FIG. This detection device is composed of a rotating shaft 1 and a magnet.
It is composed of a magnetic body rotating body 42 as a magnetic field change imparting means which rotates in synchronization with the magnetic body rotating body 42, and a GMR element 10 arranged with a predetermined gap from the magnetic body rotating body 42. Then, when the magnetic body rotating body 42 rotates, the magnetic field of the magnetic sensitive surface 10b of the GMR element 10 changes by the magnetic pole of the magnet, and the resistance value of the magnetoresistive pattern 10a changes.

Next, in the case where, for example, a Wheatstone bridge circuit as described with reference to FIG. 3 is constituted by the GMR element 10 arranged with a predetermined gap with the magnetic rotating body 42 constituted by such a magnet. The operation will be described with reference to FIG. The GMR element 10 that constitutes the Wheatstone bridge circuit 11, that is, 10 by the magnetic pole of the magnet ((a) of FIG. 15) as the magnetic body rotating body 42 rotates.
The magnetic fields of the magnetic sensitive surfaces of A, 10B, 10C, and 10D change, and their resistance values change. Along with this, the output of the connection point 18 and the output of the connection point 19 also change according to the change in the magnetic field. The output difference is amplified by the differential amplifier circuit 12, and as a result, the output side of the differential amplifier circuit 12 corresponds to the magnetic poles of the magnet of the magnetic body rotating body 42 as shown in FIG. Output is obtained.

The output of the differential amplifier circuit 12 is supplied to a comparison circuit 13 where it is compared with a reference value and converted into an "O" or "1" signal, and this signal is further converted into a waveform shaping circuit 14. As a result, the output side, that is, the output terminal 15, has a sharp rise and fall "O" corresponding to the magnetic pole of the magnet of the magnetic body rotating body 42 on the output side, that is, the output terminal 15, as shown in FIG. Alternatively, a signal of "1" is obtained.

As described above, in the present embodiment, the magnetic field of the GMR element portion is changed by the magnetic poles of the magnets constituting the magnetic body rotating body, and the magnetic body rotating body is driven from the moment the power is supplied to the detection device. The output corresponding to the magnetic poles of the magnet can be accurately obtained, and the power-on function can be stably obtained. Further, by detecting the magnetic poles of the magnets forming the magnetic body rotating body, it is difficult to be influenced by external noise, and a signal corresponding to the magnetic poles can be stably obtained. Further, in the present embodiment, the N pole and the S pole of the magnet of the magnetic body rotating body alternately correspond to the magnetically sensitive surfaces of the GMR element as the magnet rotates, that is, the magnetic flux is substantially opposite to one direction. Since it is detected in both directions, as can be seen from the comparison of the output characteristics of the differential amplifier circuits of FIG. 13 and FIG. 15, an output with a larger amplitude than that of the fifth embodiment can be obtained. It is not necessary to attach the magnet to the magnetic body rotating body as in the fifth embodiment.

Embodiment 7 FIG. Embodiments 5 and 6 above
In the above, the GMR element 10 constitutes a Wheatstone bridge circuit to detect the magnetic field change due to the rotation of the magnet included in the magnetic body rotating body 41 or the magnetic body rotating body 42 formed of the magnet. In consideration of the accuracy of assembling and attaching the magnetic body rotating body and the GMR element, the output of the GMR element, and the detection accuracy, if there is a deviation in the rotational axis direction, the output becomes small and the detection accuracy becomes poor. In order to further reduce the influence on the GMR element mounting accuracy (deviation) in the rotation axis direction, that is, in order to further reduce the constraint on the mounting accuracy (deviation) in the rotation axis direction, the shape of the GMR element is increased in the rotation axis direction. To do.

FIG. 16 is a block diagram showing a seventh embodiment of the present invention. In the figure, the parts corresponding to those in FIGS. 6 and 11 are designated by the same reference numerals for description. This detecting device includes a rotating shaft 1, a magnet 40 having at least one magnetic pole, a magnetic body rotating body 41 including the magnet 40 and rotating in synchronization with the rotating shaft 1, and a magnetic body rotating body. Four
1 and a GMR element 30 arranged with a predetermined gap. Here, the magnetic sensitive surface 30b of the GMR element 30 is set to be large in the direction of the rotation axis 1 of the magnetic body rotating body 41.
For example, the magnetic sensitive surface 30b is set to be larger than the thickness of the magnetic body rotating body 41 in the direction of the rotation axis 1. Therefore, when the magnetic body rotating body 41 rotates, the magnetic field of the magnetic sensitive surface 30b of the GMR element 30 changes due to the magnetic pole of the magnet 40 provided therein, and the resistance value of the magnetoresistive pattern 30a changes.

As described above, in the present embodiment, by setting the magnetic sensitive surface to be larger than the thickness of the magnetic body rotating body in the rotating shaft direction, it is possible to reduce the restriction on the deviation of the mounting accuracy in the rotating shaft direction. The influence on the deviation of the mounting accuracy in the rotation axis direction is reduced, and a more stable signal can be obtained. In addition, the change of the magnetic field due to the rotation of the magnetic body rotating body including the magnet having at least one magnetic pole in the GMR element is
By detecting with the MR element, a signal corresponding to the magnetic pole of the rotating magnetic body can be accurately obtained, and a power-on function can also be obtained.

Embodiment 8 FIG. 17 to 20 show Embodiment 8 of the present invention when the present device is applied to an internal combustion engine as an example. FIG. 17 is a configuration diagram showing the whole thereof, and FIG. 18 is a detection device main body and a magnetic body. 2 is a perspective view showing the positional relationship of the rotating bodies, FIG. 19 is a perspective view showing the detection device main body, FIG.
Reference numeral 0 is the internal configuration diagram. In the figure, the detection device main body 50 is provided in the vicinity of the internal combustion engine 60, and the rotating shaft 51 utilizing the crank shaft, cam shaft, etc. is provided with at least one or more irregularities as a signal plate. Two magnetic body rotating bodies 52 are provided so as to rotate in synchronization with this. Further, the control unit 61 is connected to the circuit section of the detection device main body 50, and
It is connected to a throttle valve 63 provided in an intake pipe 62 of the internal combustion engine 60.

The detection device main body 50 is arranged near the internal combustion engine 60 so that the magnetic sensitive surface of the GMR element in the detection device main body 50 faces the magnetic body rotating body 52. As shown in FIG. 19, the detection device main body 50 includes a housing 53 and a mounting portion 54 made of resin or a non-magnetic material,
From the bottom of the housing 53, terminals 55 such as power supply terminals, ground terminals, and output terminals using lead wires for input and output are taken out. Inside the housing 53, as shown in FIG. 20, a substrate 56 on which the circuit described in FIG. 3 is arranged.
The GMR element 10 and the GMR element 57 corresponding to the magnet 4 and the magnet 58 are mounted on a part of the substrate 56, respectively.

Next, the operation will be described. Now, when the magnetic body rotating body 52 rotates in synchronization with the rotation of the rotating shaft 51 due to the startup of the internal combustion engine 60, the magnetic field of the magnetic sensitive surface of the GMR element 57 in the detection device body 50 changes corresponding to the unevenness. However, the resistance value also changes. Then, the difference in the midpoint voltage of the Wheatstone bridge circuit composed of the GMR element 57 and the like is amplified by the differential amplifier circuit, and the output thereof is compared with the reference value by the comparison circuit to become the signal of "O" or "1". The converted signal is further waveform-shaped by the waveform-shaping circuit and supplied to the control unit 61 as an "O" or "1" signal. As a result, the control unit 61 can know the rotation angle and the rotation speed of the crankshaft and the camshaft corresponding to each cylinder of the internal combustion engine 60.
Then, the control unit 61 controls the output of the detection device, that is, the signal of “O” or “1” and the throttle valve 6
A control signal is formed based on the opening degree information and the like from 3, and the control signal controls the ignition timing of an ignition plug (not shown), the injection timing of a fuel injection valve, and the like.

In the above example, a lead wire is used as the input / output terminal 55 to / from the detection device main body 50, but as shown in FIG. 21, a connector 59 detachable from the housing 53 is used. May be. in this case,
The terminal 55 is incorporated in the connector 59, and the connector 5
When 9 is inserted into the housing 53 side, the terminal 55 is connected to the circuit portion of the substrate 56. This allows
It is easy to handle, structurally simple, and easy to assemble the device.

As described above, in the present embodiment, the rotation angle (rotation speed) of the crankshaft or camshaft of the internal combustion engine can be accurately detected by using the small and inexpensive detection device, and the fine control can be performed. Further, the mountability to the internal combustion engine can be improved, the mounting is easy, and the space is also advantageous.

Embodiment 9 FIG. 22 and 23 show Embodiment 9 of the present invention when the present device is applied to an internal combustion engine as an example, and FIG. 22 is a perspective view showing an arrangement relationship between a detection device main body and a magnetic rotating body. FIG. 23 is an internal configuration diagram of the detection device. 22 and 23, portions corresponding to those in FIGS. 18 and 20 are designated by the same reference numerals, and detailed description thereof will be omitted. Further, the configuration diagram showing the whole thereof and the perspective view of the detection device main body are the same as those in FIGS. 17 and 19, respectively, and are therefore omitted here.
In the figure, a magnetic rotor 52A corresponding to the above-described magnetic rotor 42 serving as a signal plate is provided on a rotary shaft 51 using a crankshaft, a camshaft, or the like of the internal combustion engine 60 so as to rotate in synchronization therewith. . This magnetic body rotating body 52
A is also composed of a magnet, and the magnetic pole of the magnet is magnetized so as to obtain a necessary signal.

The detection device main body 50 is arranged in the vicinity of the internal combustion engine 60 (FIG. 17) so that the magnetic sensitive surface of the GMR element in the detection device main body 50 faces the magnetic rotor 52A. The detection device main body 50 includes a housing 53 and a mounting portion 54 (FIG. 19) made of resin or a non-magnetic material, and terminals such as a power supply terminal, a ground terminal, and an output terminal using lead wires for input / output from the bottom of the housing 53. 55 is taken out. Inside the housing 53, there is provided a board 56 on which the circuit as described in FIG. 3 is arranged.
A GMR element 57 corresponding to the above-mentioned GMR element 10 is mounted on a part of the above.

Next, the operation will be described. Now, when the magnetic body rotating body 52A rotates in synchronization with the rotation of the rotating shaft 51 due to the activation of the internal combustion engine 60, the magnetic field of the magnetic sensitive surface of the GMR element 57 in the detection device main body 50 corresponds to the magnetic pole of the magnet. Changes and its resistance also changes. And G
The difference in the midpoint voltage of the Wheatstone bridge circuit composed of the MR element 57 and the like is amplified by the differential amplifier circuit, and its output is compared with the reference value by the comparison circuit and converted into the signal of "O" or "1". This signal is further waveform-shaped by the waveform shaping circuit and supplied to the control unit 61 (FIG. 17) as an "O" or "1" signal. As a result, the control unit 61 can know the rotation angle and the rotation speed of the crankshaft and the camshaft corresponding to each cylinder of the internal combustion engine 60. Then, the control unit 61 forms a control signal based on the output of the detection device, that is, the signal of "O" or "1", the opening information from the throttle valve 63, and the like, and the spark plug (not shown) is generated by this control signal. It controls the ignition timing, the injection timing of the fuel injection valve, and the like.

In the above example, a lead wire is used as the input / output terminal 55 for the detection device main body 50, but as shown in FIG. May be. In this case, the terminal 55 is incorporated in the connector 59, and the connector 59
When is inserted into the housing 53 side, the terminal 55 is connected to the circuit portion of the substrate 56. This facilitates handling, structural simplification, and assembly of the device.

As described above, also in this embodiment, the rotation angle (rotation speed) of the crankshaft and the camshaft of the internal combustion engine can be accurately detected by using the small and inexpensive detection device, and the fine control can be performed. Further, the mountability to the internal combustion engine can be improved, the mounting is easy, and the space is also advantageous. Further, since the output corresponding to the magnetic pole of the magnet of the magnetic rotating body can be accurately obtained from the moment the power is supplied to the detection device, the power-on function can be stably obtained, so that the crank angle of the internal combustion engine can be quickly changed. Therefore, the ignition timing and the fuel injection timing can be quickly and accurately performed, and the exhaust gas regulation can be easily dealt with.

Embodiment 10 FIG. 25 shows Embodiment 10 of the present invention. (A) of FIG. 25 is a perspective view showing the positional relationship between the detection device main body and the magnetic rotating body, and (b) of FIG. 25 is a side view thereof. is there. In the figure, parts corresponding to those in FIG. 18 are designated by the same reference numerals, and detailed description thereof will be omitted. In each of the above-described embodiments, the detection device body is provided in the direction perpendicular to the rotation axis, but in the present embodiment, the detection device body is provided in the direction coaxial with the rotation axis. That is, as shown in (a) of FIG. 25, the detection device main body 50 is provided coaxially with the rotating shaft 51, and as shown in (b) of FIG. It is arranged so as to face the magnetically sensitive surface of the GMR element of the detection device body 50.

Thus, in the present embodiment, the same effect as in the above-described eighth embodiment can be obtained, and further, in the present embodiment, since the detection device main body can be arranged in the rotation axis direction, the rotation axis is substantially the same. The space can be shared, the shape of the device does not become large in the radial direction, and the miniaturization can be further improved.

Embodiment 11 FIG. FIG. 26 shows Embodiment 11 of the present invention. (A) of FIG. 26 is a perspective view showing the positional relationship between the detection device main body and the magnetic rotating body, and (b) of FIG. 26 is a side view thereof. is there. In the figure, parts corresponding to those in FIG. 22 are designated by the same reference numerals, and detailed description thereof will be omitted. Also in the present embodiment, as in the above-described tenth embodiment,
The detection device main body is provided coaxially with the rotation axis. That is, as shown in FIG.
The detection device main body 50 is provided coaxially with respect to the above, and as shown in FIG. 26B, it is arranged so that the magnetic pole of the magnetic body rotating body 52A faces the magnetically sensitive surface of the GMR element of the detection device main body 50. .

Thus, in this embodiment as well, the same effects as those of the above-described ninth embodiment can be obtained, and further, in this embodiment, since the detection device main body can be arranged in the rotation axis direction, the rotation axis is substantially the same. The space can be shared, the shape of the device does not become large in the radial direction, and the miniaturization can be further improved.
Of course, as the magnetic body rotating body, the magnet 40 shown in FIG.
The magnetic rotating body 41 provided with may be used, and the same effect can be obtained.

Embodiment 12 FIG. 27 and 28 show
Embodiment 12 of the present invention is shown, FIG. 27 is a side sectional view thereof, and FIG. 28 is a schematic view of a detection device main body. 18, parts corresponding to those in FIGS. 18 and 20 are designated by the same reference numerals, and detailed description thereof will be omitted. In each of the above-described embodiments, the GMR element of the main body of the detection device and the magnetic rotating body are arranged with a predetermined gap therebetween, but in the present embodiment, the GMR of the main body of the detection device is arranged. The magnetic body rotating body is arranged so as to be sandwiched between the element and the magnet with a predetermined gap.

The detection device main body 50A includes a housing 70 made of, for example, resin or a non-magnetic material, and the housing 7
The GMR element 10 described above provided in the cavity 70a
Cover 71 for protecting a considerable GMR element 57 and the like
And a mounting portion 74, and the cavity 70a in the housing 70 is provided with a substrate (not shown) on which the circuit as described in FIG. 3 is arranged, and the GMR element 57 is provided in a part of this substrate. It will be installed. The GMR element 57 has a terminal 72.
Are electrically connected to each other, and the terminal 72 extends to the bottom through the inside of the detection device main body 50A, and terminals 73 such as a power supply terminal, a ground terminal, an output terminal, etc. using lead wires for input and output thereto. Is connected and taken out. Further, below the space 70b on the side surface of the housing 70, the magnet 5 faces the magnetic sensitive surface of the GMR element 57 in the cavity 70a.
8 is provided, and the magnetic body rotating body 52 is provided such that at least the uneven portion of the magnetic body rotating body 52 that rotates in synchronization with the rotating shaft 51 passes between the GMR element 57 and the magnet 58.
Is arranged.

With this structure, the magnet 5
8, the magnetic path passing through the magnetic body rotating body 52 and the GMR element 57 is substantially formed, and the magnetic field from the magnet 58 is generated when the concave portion of the magnetic body rotating body 52 is located between the GMR element 57 and the magnet 58. Is applied to the magnetically sensitive surface of the GMR element 57 as it is, while the magnetic field from the magnet 58 flows toward the magnetic body rotating body 52 in a state where the convex portion of the magnetic body rotating body 52 is positioned, and the GMR element is substantially. It cannot be applied to the magnetic sensitive surface of 57.
That is, as described above with reference to FIGS. 11 and 14, this is substantially the same as the state where at least a part of the magnetic body rotating body 52 is composed of a magnet, and therefore, this In this case, the power-on function can be obtained.

In the above example, the magnet 58 is provided below the space 70b on the side surface of the housing 70 so as to face the magnetically sensitive surface of the GMR element 57 in the cavity 70a. As shown in FIG.
A core 75 may be provided between the two to form a magnetic circuit. As a result, the magnet 58-the magnetic body rotating body 52-
GMR element 57-magnetic body rotating body 52-core 75-magnet 5
The closed magnetic circuit of 8 is substantially formed, a more reliable magnetic circuit is established, and the detectability is improved.

Thus, in this embodiment as well, the same effect as in the above-described eighth embodiment can be obtained, and further, in this embodiment, it is necessary to consider the positioning of the magnetic rotating body between the GMR element and the magnet. However, the power-on function can be obtained.

Thirteenth Embodiment FIG. 30 is a side sectional view showing Embodiment 13 of the present invention. In the figure, FIG.
2 and parts corresponding to those in FIG. 27 are designated by the same reference numerals, and detailed description thereof will be omitted. In the twelfth embodiment, the case where an ordinary magnetic body rotating body having the irregularities as shown in FIG. 18 is used as the magnetic body rotating body, but in the present embodiment, a magnet is used as the magnetic body rotating body. It is configured (see FIG. 14 or FIG. 22) or is equipped with a magnet (see FIG. 11), and here, as an example, a case where the magnetic body rotating body is configured by a magnet. Therefore, in this case, the magnet 58 used in FIG. 27 is unnecessary. Other configurations are the same as those in FIG. Therefore, at least the peripheral portion of the magnetic body rotating body 52A that rotates so as to face the magnetic sensitive surface of the GMR element 57 in the hollow portion 70a passes through the space portion 70b on the side surface of the housing 70 that constitutes the detection device main body 50B, The magnetic body rotating body 52A is arranged.

Therefore, also in this case, the magnetic body rotating body 52A
And a magnetic path through the GMR element 57 is substantially formed,
Detectability is improved. Of course, also in this case, the power-on function can be obtained. Thus, also in the present embodiment, the same effect as that of the above-described ninth embodiment can be obtained, and further, in the present embodiment, the detectability is improved.

Embodiment 14 FIG. In each of the above-mentioned embodiments, the magnetic body moving body as the magnetic field change giving means is
The case of the magnetic body rotating body that rotates in synchronization with the rotation axis has been described, but the same can be applied to the magnetic body moving body that linearly displaces, and the same effect can be obtained. In this case, for example, application to detection of the valve opening degree of the EGR valve in the internal combustion engine or the like can be considered.

[0078]

As described above, according to the first aspect of the invention, the magnetic field generating means for generating a magnetic field and the magnetic field generating means are arranged with a predetermined gap, and the magnetic field generating means generates the magnetic field. Since the magnetic field change giving means for changing the magnetic field and the giant magnetoresistive element whose resistance value changes according to the magnetic field changed by the magnetic field change giving means are provided, the magnetic sensitive surface of the giant magnetoresistive element is anisotropic. Since there is no restriction, there is less restriction on the mounting accuracy (deviation) of the magnetic field change applying means, it is possible to stably detect the magnetic field change, and the amount of resistance change of the giant magnetoresistive element also increases stably. In addition, the giant magnetoresistive element is in-plane magnetically sensitive and does not need to form a magnetically sensitive pattern by etching or the like like an MR element, and thus a detection device can be obtained. Can be downsized Ri, cost there is an effect that can be less expensive.

According to the invention of claim 2, in the invention of claim 1, since the magnetic field change imparting means is constituted by the magnetic body moving body having at least one unevenness, it is possible to detect even small unevenness and detect it. There is an effect that the detection accuracy can be improved as well as the size and cost of the device can be reduced.

According to the invention of claim 3, in the invention of claim 1, the magnetic field generating means and the magnetic field change giving means are constituted by a magnetic body moving body having at least one magnetic pole to generate and change a magnetic field. With this configuration, the output corresponding to the magnetic pole of the magnet provided in the magnetic body moving body can be accurately obtained from the moment the power is supplied to the detection device, and the power-on function is stably obtained. There is an effect.

According to the invention of claim 4, in the invention of claim 2 or 3, the giant magnetoresistive element is enlarged in a direction orthogonal to the moving direction of the magnetic body moving body.
The magnetically sensitive surface of the giant magnetoresistive element is substantially enlarged in the direction orthogonal to the moving direction of the magnetic body moving body, and the constraint on the deviation of the mounting accuracy of the magnetic body moving body can be reduced, resulting in a more stable signal. Can be obtained.

According to the invention of claim 5, claim 1
In any one of the inventions of 4 to 4), since the bridge circuit using the giant magnetoresistive element on at least one side and the signal processing means for processing the output of the bridge circuit are provided, the magnetic sensitive surface of the giant magnetoresistive element is provided. Since there is no anisotropy, a magnetic field change can be detected stably, and the amount of resistance change of the giant magnetoresistive element also increases stably, the output of the signal processing means also increases, and "0" or "1"
The margin with respect to the determination level at the time of conversion into the signal of is increased, the resistance against external noise is increased, and a stable signal can be obtained.

According to the invention of claim 6, in the invention of claim 5, the two sides of the bridge circuit are composed of giant magnetoresistive elements, and the remaining two sides are composed of fixed resistors, which is inexpensive. With the configuration, there is an effect that it is strong against external noise and a stable signal is obtained.

According to the invention of claim 7, in the invention of claim 6, one set of opposite sides of the bridge circuit is composed of giant magnetoresistive elements, and the other set of opposite sides is composed of fixed resistors, which is inexpensive. With such a configuration, there is an effect that a stable signal can be obtained, which is strong against external noise.

According to the invention described in claim 8,
In any one of the seventh aspect, since the magnetic body moving body is a rotating body that rotates in synchronization with the rotation axis, it is possible to reliably detect a change in the magnetic field due to the rotation of the rotating body.

According to a ninth aspect of the present invention, in the eighth aspect of the present invention, the rotating body is equipped with a detection device main body including at least a giant magnetoresistive element, and the rotating body is mounted on a crankshaft or a camshaft of an internal combustion engine. Since the detector main body is arranged in the vicinity of the internal combustion engine so as to face the giant magnetoresistive element,
A small and inexpensive detection device can be used to accurately detect the rotation angle (rotation speed) of the crankshaft and camshaft of the internal combustion engine, which enables fine control and improves the mountability on the internal combustion engine. It is easy and advantageous in terms of space, and there is an effect that the apparatus can be made compact. is there.

According to the invention of claim 10, claim 9 is provided.
In the invention, since the detection device main body is arranged in the rotation axis direction with respect to the rotating body, the space of the rotation shaft can be substantially shared, the shape of the device does not become large in the radial direction, and the miniaturization can be further promoted. effective.

According to the invention of claim 11, claim 1
In the invention of No. 0, the main body of the detection device includes a housing in which at least a giant magnetoresistive element is incorporated, and the rotor is provided in a space formed on a side surface of the housing so that at least a peripheral portion of the rotor faces the giant magnetoresistive element. Since the magnetic path that passes through the rotating body and the giant magnetoresistive element is formed substantially, and at least a part of the rotating body is formed of a magnet, The output corresponding to the rotation angle of the rotating body can be accurately obtained from the moment the power is supplied to the detection device, and the power-on function can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a detection device according to the present invention.

FIG. 2 is a block diagram showing a circuit configuration of the detection device according to the first embodiment of the present invention.

FIG. 3 is a circuit diagram showing an example of a specific circuit configuration of FIG. 2;

4 is a diagram schematically showing a state in which four GMR elements forming the Wheatstone bridge circuit of FIG. 3 are arranged on a substrate.

5 is a waveform diagram for explaining the operation of FIG.

FIG. 6 is a configuration diagram showing a second embodiment of a detection device according to the present invention.

FIG. 7: Two GMs forming a Wheatstone bridge circuit in the third embodiment of the detection device according to the present invention
It is a figure which shows typically the state which has arrange | positioned the R element on the board | substrate.

8 is a waveform diagram for explaining the operation of FIG.

FIG. 9: Two GMs forming a Wheatstone bridge circuit in the fourth embodiment of the detection apparatus according to the present invention
It is a figure which shows typically the state which has arrange | positioned the R element on the board | substrate.

10 is a waveform diagram for explaining the operation of FIG.

FIG. 11 is a configuration diagram showing a fifth embodiment of a detection device according to the present invention.

FIG. 12 is a block diagram showing a circuit configuration of a fifth embodiment of a detection device according to the present invention.

13 is a waveform chart for explaining the operation of FIG.

FIG. 14 is a configuration diagram showing a sixth embodiment of a detection device according to the present invention.

15 is a waveform chart for explaining the operation of FIG.

FIG. 16 is a configuration diagram showing a seventh embodiment of a detection device according to the present invention.

FIG. 17 is a configuration diagram showing an eighth embodiment of the detection device according to the present invention.

FIG. 18 is a perspective view showing an arrangement relationship between a detection device main body and a magnetic rotating body in the eighth embodiment of the detection device according to the present invention.

FIG. 19 is a perspective view showing a detection device main body according to the eighth embodiment of the detection device of the present invention.

FIG. 20 is an internal configuration diagram of a detection device body in the eighth embodiment of the detection device according to the present invention.

FIG. 21 is a side sectional view showing another example of the detection device body in the eighth embodiment of the detection device according to the present invention.

FIG. 22 is a configuration diagram showing a ninth embodiment of the detection device according to the present invention.

FIG. 23 is an internal configuration diagram of a detection device body according to a ninth embodiment of the detection device of the present invention.

FIG. 24 is a side sectional view showing another example of the detection device body in the ninth embodiment of the detection device according to the present invention.

FIG. 25 is a tenth embodiment of a detection device according to the present invention.
It is a block diagram which shows.

FIG. 26 is an eleventh embodiment of the detection device according to the present invention.
It is a block diagram which shows.

FIG. 27 is a twelfth embodiment of the detection device according to the present invention.
FIG.

FIG. 28 is a twelfth embodiment of the detection device according to the present invention.
3 is a perspective view showing the main body of the detection device in FIG.

FIG. 29 is a twelfth embodiment of the detection device according to the present invention.
It is a side sectional view showing another example in.

FIG. 30 is a thirteenth embodiment of the detection device according to the present invention.
FIG.

FIG. 31 is a configuration diagram showing a conventional detection device.

FIG. 32 is a schematic diagram showing a circuit configuration of a conventional detection device.

[Explanation of symbols]

1,51 rotating shaft, 2,41,42,52,52A magnetic body rotating body, 4,31,40 magnet, 10,10A to 1
0D, 30 GMR element, 11 Wheatstone bridge circuit, 12 differential amplifier circuit, 13 comparison circuit, 14
Waveform shaping circuit, 50, 50A, 50B detection device body,
53 Housing.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Wataru Fukui 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Corporation (72) Inventor Yutaka Ohashi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Rishi Electric Co., Ltd.

Claims (11)

[Claims] 1. A magnetic field generating means for generating a magnetic field, a magnetic field change applying means arranged with a predetermined gap from the magnetic field generating means for changing the magnetic field generated by the magnetic field generating means, and the magnetic field change applying means. And a giant magnetoresistive element whose resistance value changes according to the magnetic field changed by the means. 2. The detection device according to claim 1, wherein the magnetic field change imparting means is constituted by a magnetic body moving body having at least one unevenness. 3. The magnetic field generating means and the magnetic field change giving means are composed of a magnetic body moving body having at least one magnetic pole, and generate and change a magnetic field. Detection device. 4. The detection device according to claim 2, wherein the giant magnetoresistive element is enlarged in a direction orthogonal to the moving direction of the magnetic body moving body. 5. A bridge circuit using the giant magnetoresistive element on at least one side, and a signal processing means for signal-processing the output of the bridge circuit. The detection device according to 1. 6. The detection device according to claim 5, wherein two sides of the bridge circuit are formed of the giant magnetoresistive element, and the remaining two sides are formed of fixed resistors. 7. The detection device according to claim 6, wherein one set of opposite sides of the bridge circuit is composed of the giant magnetoresistive element, and the other set of opposite sides is composed of a fixed resistor. 8. The detection device according to claim 1, wherein the magnetic body moving body is a rotating body that rotates in synchronization with a rotation axis. 9. A detection device main body including at least the giant magnetoresistive element, wherein the rotating body is mounted on a crankshaft or a camshaft of an internal combustion engine, and the rotating body faces the giant magnetoresistive element. 9. The detection device according to claim 8, wherein the detection device main body is arranged near the internal combustion engine. 10. The detection device according to claim 9, wherein the detection device main body is arranged in the rotation axis direction with respect to the rotating body. 11. The detection device main body includes a housing containing at least the giant magnetoresistive element, and the rotating body is provided in a space formed on a side surface of the housing so that at least a peripheral portion of the rotating body has the giant body. The detection device according to claim 10, wherein the detection device is arranged so as to face the magnetoresistive element.