JP4737371B2 - Rotation angle detector - Google Patents

Description

  The present invention relates to a detection device that detects the direction of an external magnetic field using a magnetoresistive effect element. For example, the rotation device is attached to a rotary shaft of a throttle valve of an internal combustion engine and is suitable for use in detecting the throttle opening. The present invention relates to an angle detection device.

As this type of conventional rotation angle detection device, a rotation angle sensor of the following Patent Document 1 is known, and the first element substrate 2A to the fourth element substrate 2D having the magnetoresistive effect element 1 as shown in FIG. And a wiring board 3 that constitutes a circuit by connecting the element substrates 2A to 2D. On the surface of the wiring board 3, the first element substrate 2A to the fourth element substrate 2D are individually arranged. And at least one set of the element substrates is disposed so as to be inclined by 80 ° to 100 °. Further, the magnetic field generating means 5 for applying an external magnetic field to the first element substrate 2A to the fourth element substrate 2D having the magnetoresistive effect element 1 includes a rotating shaft 10 as an object to be detected and an end portion thereof. The integrated circular member 11 (which may be a gear or the like) and permanent magnets 12A and 12B fixed to the end face of the circular member 11 at intervals of 180 °, each of the first element substrate 2A to the fourth element substrate 2D. In this configuration, an external magnetic field having a substantially uniform direction can be applied.
JP 2001-159542 A

  By the way, in the conventional rotation angle detection apparatus, the 1st-4th element board | substrate which has a magnetoresistive effect element is separately arrange | positioned on the surface of the said wiring board, and at least 1 set of said element substrates is 80 degrees-100. In order to incline, the man-hour for arranging the element substrate increases. In addition, there is a problem that variation in magnetic field detection accuracy increases due to variation in position due to the arrangement of the element substrates.

  In view of the above points, the present invention uses a vector detection type magnetoresistive effect element as a magnetoresistive effect element, and provides a plurality of vector detection type magnetoresistive effect elements having substantially the same pin layer magnetization direction on the same element substrate. Thus, the workability for arranging the element substrate on the mounting surface of the wiring member is improved, the magnetic field detection accuracy is improved, and as a result, the magnetic field rotating relative to the vector detection type magnetoresistive effect element is improved. An object of the present invention is to provide a rotation angle detection device capable of improving the rotation angle detection accuracy.

  Other objects and novel features of the present invention will be clarified in embodiments described later.

In order to achieve the above object, the first invention provides:
A vector detection type magnetoresistive effect element on an element substrate which is arranged in the magnetic field of the magnetic field generating means and whose resistance value changes according to the direction of the magnetic field, and the vector detection type magnetoresistive effect element are connected to form a circuit. Rotation angle detection for detecting a throttle opening degree in which the magnetic field rotates relative to the vector detection type magnetoresistive effect element with rotation of a rotation shaft of a throttle valve which is a detected object. A device,
Two vector-detecting magnetoresistive elements having substantially the same pin layer magnetization direction are provided on the same element substrate, and the two element substrates are arranged on the mounting surface of the wiring member , and one of the elements the first element and the pin layer magnetization direction of the second element is the vector-detecting magnetoresistive element on a substrate, the third element and the fourth is the vector-detecting magnetoresistive element of the other of said element substrate Is substantially antiparallel to the pin layer magnetization direction of the element ,
The first element and the third element have a first output portion between the elements and are connected in series to form a first series circuit, and the second element and the fourth element are between the elements. A second output circuit configured to be connected in series to form a second series circuit, the first and second series circuits having the first element and the second element side as a common input unit; 3 element and a side of said fourth element is fixed to a common potential are connected in parallel is characterized in Rukoto.

In addition, the second invention,
A circuit by connecting the vector detection type magnetoresistive element of the element substrate on which resistance value changes according to the direction of those magnetic field is disposed in the magnetic field of the magnetic field generating means, the vector detecting magnetoresistive element A rotation angle for detecting a throttle opening, in which the magnetic field rotates relative to the vector detection type magnetoresistive effect element in accordance with rotation of a rotation shaft of a throttle valve which is a detected object. A detection device,
Two vector-detecting magnetoresistive elements having substantially the same pin layer magnetization direction are provided on the same element substrate, and the two element substrates are arranged on the mounting surface of the wiring member , and one of the elements and the pinned layer magnetization directions of the first element and the second element is the vector-detecting magnetoresistive element on a substrate, and the third element is the other of the vector detection type magnetoresistive element of the element substrate 4 The pinned layer magnetization direction of the element is a direction facing each other, or vice versa .
The first element and the third element have a first output portion between the elements and are connected in series to form a first series circuit, and the second element and the fourth element are between the elements. A second output circuit configured to be connected in series to form a second series circuit, the first and second series circuits having the first element and the second element side as a common input unit; 3 element and a side of said fourth element is fixed to a common potential are connected in parallel is characterized in Rukoto.

In the rotation angle detection device, a mark for determining the pinned layer magnetization direction may be added on the surfaces of the two element substrates.

  In the rotation angle detection device, the vector detection type magnetoresistance effect element may be a spin valve type giant magnetoresistance effect element.

  According to the rotation angle detection device of the present invention, a vector detection type magnetoresistive effect element is used as the magnetoresistive effect element, and a plurality of vector detection type magnetoresistive effect elements having substantially the same pin layer magnetization direction are arranged on the same element substrate. Since it was provided above, the workability of arranging the element substrate on the mounting surface of the wiring member is improved. Further, since a plurality of vector detection type magnetoresistive effect elements are provided on the same element substrate, the wiring member is attached as compared with the case where a plurality of one element substrate having one magnetoresistive effect element is provided on the wiring member. It is possible to improve the detection accuracy in the direction of the magnetic field by eliminating the characteristic variation and the positional variation between the elements when the element substrate is arranged on the surface.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a rotation angle detection device will be described below with reference to the drawings as the best mode for carrying out the present invention.

  A first embodiment of a rotation angle detection device according to the present invention will be described with reference to FIGS. In the present embodiment, a spin-valve giant magnetoresistive element (hereinafter referred to as an SV-GMR element) is used as the vector detecting magnetoresistive element. This SV-GMR element includes a pinned layer (pinned magnetic layer) whose magnetization direction is fixed in one direction, a nonmagnetic layer through which a current mainly flows, and a free layer whose magnetization direction matches the external magnetic field direction (external magnetic flux direction). When the magnetization direction of the pinned layer coincides with the vector direction of the external magnetic field, the resistance value is low, and when the direction is opposite, the resistance value is high (details of the operation will be described later with reference to FIG. 8).

  As shown in FIGS. 1A, 1B, and 2, the pin substrate magnetization direction is substantially the same as the element substrate 21 provided with the SV-GMR elements R1, R2 having substantially the same pin layer magnetization direction. The element substrate 22 provided with the SV-GMR elements R3 and R4 is used, and the pin layer magnetization directions are antiparallel (substantially antiparallel to each other) on the mounting surface of the wiring board 30 serving as the wiring member. May be arranged and fixed. Here, anti-parallel means that the vectors are parallel but the directions are opposite to each other. In each of the element substrates 21 and 22, the two SV-GMR elements are linearly arranged along the pinned layer magnetization direction, and the magnetosensitive surface of each SV-GMR element is considered to be the upper surface of the element substrate. Good. The wiring board 30 is fixed to a detection device support 31.

  As for the element substrate, tens of thousands of SV-GMR elements having the pinned layer magnetized in the same direction are simultaneously manufactured on one large substrate, and a plurality of SV-GMR elements are formed from the large substrate. A device substrate (two in the present embodiment) cut out side by side is referred to as an element substrate.

  On the other hand, the magnetic field generating means 5 for applying an external magnetic field having a substantially uniform direction to the SV-GMR elements R1 to R4 may be the same as in the prior art of FIG. 10 and a circular member 11 (which may be a gear or the like) integrated at the end, and permanent magnets 12A and 12B fixed to the end surface of the circular member 11 at intervals of 180 °. Therefore, the direction of the external magnetic field applied to the SV-GMR elements R1 to R4 is the direction from the N pole of one permanent magnet 12A to the S pole of the other permanent magnet 12B. The direction of the magnetic field is also rotated 360 °. The rotary shaft 10 is, for example, a rotary shaft of a throttle valve in a rotation angle detection device that detects the throttle opening of an internal combustion engine.

  In FIG. 1 and FIG. 2, the SV-GMR elements R <b> 1 to R <b> 4 are illustrated larger than the wiring substrate 30 for easy understanding, but in actuality, the dimensions are small.

  As shown in FIG. 3, the SV-GMR elements are connected to each other by the wiring pattern of the wiring board 30, and among the four SV-GMR elements R <b> 1 to R <b> 4, the SVs whose pinned layer magnetization directions are opposite to each other. -GMR elements R1 and R3 have a first output section between the elements and are connected in series to form a first series circuit. The SV-GMR element R2 whose pinned layer magnetization direction is the same as that of the SV-GMR element R1 and the SV-GMR element R4 whose pinned layer magnetization direction is the same direction as that of the SV-GMR element R3 are Two output units are connected in series to form a second series circuit, and the first and second series circuits are connected in parallel with SV-GMR elements R1 and R2 as input units. One ends of the SV-GMR elements R3 and R4 are connected to the ground (GND). An output 1 is obtained between the first output unit and the ground, and an output 2 is obtained between the second output unit and the ground. Both the output 1 and the output 2 are substantially sine waves (the operation principle will be described with reference to FIG. 8 below).

  As shown in FIG. 8A, the SV-GMR element has a pinned layer (pinned magnetic layer) whose magnetization direction is fixed in one direction, a nonmagnetic layer through which current mainly flows, and a magnetization direction in the external magnetic field direction (external). And a free layer (free layer) coinciding with the (magnetic flux direction). When the pin layer magnetization direction matches the external magnetic field vector direction, the resistance value is low. When the external magnetic field vector direction is rotated in the SV-GMR element plane, the resistance value changes depending on the angle formed with the pin layer magnetization direction. In the opposite direction, the resistance value is high. This characteristic is the in-plane magnetic characteristic of the SV-GMR element shown in FIG. 8B, and the external magnetic field is perpendicular to the magnetosensitive surface under the condition that an external magnetic field parallel to the magnetosensitive surface of the SV-GMR element exists. This shows the relationship between the rotation angle with respect to the pinned layer magnetization direction and the resistance change rate (ΔR / R). In this case, the rate of change in resistance (ΔR / R) changes gently with a waveform close to a sine wave, and no saturation region occurs.

  In this embodiment, the in-plane magnetic characteristics of the SV-GMR element shown in FIG. 8B are used. That is, the external magnetic field generated by the magnetic field generating means 5 shown in FIGS. 1A and 1B rotates as the rotating shaft 10 rotates, and when the rotating shaft 10 rotates once, the external magnetic field also rotates 360 °. Therefore, with one rotation of the rotating shaft 10, a voltage waveform having a substantially sine wave of one cycle (substantially a sine wave) can be obtained between the output 1 and the ground and between the output 2 and the ground in FIG. can get.

  According to the first embodiment, the following effects can be obtained.

(1) Since the SV-GMR element Rl and the SV-GMR element R2 are provided on the same element substrate 21 and can be simultaneously disposed on the mounting surface of the wiring substrate 30, workability is good. Further, since the positional variation or the like when arranged on the mounting surface of the wiring board 30 is not affected between the SV-GMR element R1 and the SV-GMR element R2, the magnetic field detection accuracy is improved. The SV-GMR element R3 and the SV-GMR element R4 are also provided on the same element substrate 22, and the same effect can be obtained.

(2) The element substrates 21 and 22 are produced by simultaneously producing tens of thousands of SV-GMR elements in which the pinned layers are magnetized in the same direction on one large substrate, and the SV-GMR elements are formed from the large substrates. A plurality of (two) elements are cut out side by side, and the SV-GMR elements on the same element substrate have the same characteristics. Therefore, the magnetic field detection accuracy can be improved in this respect as well.

  FIG. 4 shows a second embodiment of the present invention, in which an element substrate 23 in which SV-GMR elements R1 and R2 having substantially the same pinned layer magnetization direction are arranged in parallel and an SV− having substantially the same pinned layer magnetization direction are provided. An element substrate 24 provided with GMR elements R3 and R4 arranged in parallel is used. The element substrates 23 and 24 are arranged and fixed on the mounting surface of the wiring substrate 30 so that the pinned layer magnetization directions of the SV-GMR elements face each other.

  The other overall configuration is the same as in FIG. 1, and the connections between the SV-GMR elements are as shown in FIG. 3. In this case as well, the rotation angle of the external magnetic field by the magnetic field generating means is implemented by the SV-GMR elements R1 to R4. Detection is possible in the same manner as in the first embodiment.

  FIG. 5 shows a third embodiment of the present invention, in which an element substrate 23 in which SV-GMR elements R1 and R2 having substantially the same pin layer magnetization direction are arranged in parallel and an SV− having substantially the same pin layer magnetization direction are provided. An element substrate 24 provided with GMR elements R3 and R4 arranged in parallel is used. The element substrates 23 and 24 are arranged and fixed on the mounting surface of the wiring board 30 so that the pin layer magnetization directions of the SV-GMR elements are opposite to each other.

  The other overall configuration is the same as in FIG. 1, and the connections between the SV-GMR elements are as shown in FIG. 3. In this case as well, the rotation angle of the external magnetic field by the magnetic field generating means is implemented by the SV-GMR elements R1 to R4. Detection is possible in the same manner as in the first embodiment.

  FIGS. 6A and 6B show element substrates 21 and 22 having a plurality of SV-GMR elements that can be used in the first embodiment, and are discriminating marks 41 for discriminating the pinned layer magnetization direction. The structure which provided 42 is shown.

  6 (C) and 6 (D) show element substrates 23 and 24 having a plurality of SV-GMR elements that can be used in the second and third embodiments, for determining the pinned layer magnetization direction. The structure provided with the discrimination marks 43 and 44 is shown.

  The discrimination marks 41 to 44 have a triangular shape as shown in the figure, for example, and the direction of the apex indicates the pinned layer magnetization direction.

  The specific shape of the discrimination mark can be variously changed as long as the pinned layer magnetization direction can be displayed.

  In each of the above embodiments, the case where the wiring board is used as the wiring member has been described. However, a lead frame or the like can be used as the wiring member.

  Although the embodiments of the present invention have been described above, it will be obvious to those skilled in the art that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims.

It is Embodiment 1 of the rotation angle detection apparatus which concerns on this invention, Comprising: (A) is a front view, (B) is a top view. FIG. 3 is a perspective view showing a configuration of a wiring board to which an element substrate is attached in the first embodiment. FIG. 3 is a circuit diagram showing connection of each SV-GMR element by the wiring board in the first embodiment. It is Embodiment 2 of this invention, Comprising: It is a perspective view which shows the structure of the wiring board which attached the element substrate. It is Embodiment 3 of this invention, Comprising: It is a perspective view which shows the structure of the wiring board which attached the element substrate. It is an example of the element board | substrate which has a discrimination mark, Comprising: (A) And (B) is a perspective view which respectively shows the element board | substrate which has a discrimination mark which can be used in Embodiment 1, (C) and (D) are implementation. It is a perspective view which shows each element substrate which has a discrimination mark which can be used with form 2 and 3. It is a perspective view which shows one example of the conventional rotation angle detection apparatus. FIG. 4A is a diagram for explaining the operation of the SV-GMR element. FIG. 4A is an explanatory diagram showing a film configuration of the SV-GMR element, and FIG. 4B is an explanatory diagram showing in-plane magnetic characteristics of the SV-GMR element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetoresistance effect element 2A-2D, 21-24 Element board | substrate 3,30 Wiring board 10 Rotating shaft 11 Circular member 12A, 12B Permanent magnet 31 Detection apparatus support stand 41-44 Discrimination mark R1-R4 SV-GMR element

Claims (4)

A vector detection type magnetoresistive effect element on an element substrate which is arranged in the magnetic field of the magnetic field generating means and whose resistance value changes according to the direction of the magnetic field, and the vector detection type magnetoresistive effect element are connected to form a circuit. Rotation angle detection for detecting a throttle opening degree in which the magnetic field rotates relative to the vector detection type magnetoresistive effect element with rotation of a rotation shaft of a throttle valve which is a detected object. A device,
Two vector-detecting magnetoresistive elements having substantially the same pin layer magnetization direction are provided on the same element substrate, and the two element substrates are arranged on the mounting surface of the wiring member , and one of the elements the first element and the pin layer magnetization direction of the second element is the vector-detecting magnetoresistive element on a substrate, the third element and the fourth is the vector-detecting magnetoresistive element of the other of said element substrate Is substantially antiparallel to the pin layer magnetization direction of the element ,
The first element and the third element have a first output portion between the elements and are connected in series to form a first series circuit, and the second element and the fourth element are between the elements. A second output circuit configured to be connected in series to form a second series circuit, the first and second series circuits having the first element and the second element side as a common input unit; 3 the rotation angle detecting device is connected to the element to a side of the fourth element in parallel and fixed to a common potential and said Rukoto. A circuit by connecting the vector detection type magnetoresistive element of the element substrate on which resistance value changes according to the direction of those magnetic field is disposed in the magnetic field of the magnetic field generating means, the vector detecting magnetoresistive element A rotation angle for detecting a throttle opening, in which the magnetic field rotates relative to the vector detection type magnetoresistive effect element in accordance with rotation of a rotation shaft of a throttle valve which is a detected object. A detection device,
Two vector-detecting magnetoresistive elements having substantially the same pin layer magnetization direction are provided on the same element substrate, and the two element substrates are arranged on the mounting surface of the wiring member , and one of the elements and the pinned layer magnetization directions of the first element and the second element is the vector-detecting magnetoresistive element on a substrate, and the third element is the other of the vector detection type magnetoresistive element of the element substrate 4 The pinned layer magnetization direction of the element is a direction facing each other, or vice versa .
The first element and the third element have a first output portion between the elements and are connected in series to form a first series circuit, and the second element and the fourth element are between the elements. A second output circuit configured to be connected in series to form a second series circuit, the first and second series circuits having the first element and the second element side as a common input unit; 3 the rotation angle detecting device is connected to the element to a side of the fourth element in parallel and fixed to a common potential and said Rukoto. On the surface of two of said device substrate, the rotation angle detection apparatus according to claim 1 or 2, wherein the obtained by adding a mark to determine the pinned layer magnetization direction. The vector detecting magnetoresistive element is a rotational angle detecting device according to claim 1, 2 or 3, wherein the a spin-valve giant magnetoresistive element.

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