JP5290675B2 - Rotation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation detecting apparatus configuring a small (thin), less restricted circuit board wiring pattern and capable of reducing an effect of sliding wear on a circuit. <P>SOLUTION: A rotation sensor 10 includes an upper housing 11, a lower housing 12, a circuit board 13, a Hall element 14, a first rotating body 15, and a second rotating body 16. The second rotating body 16 includes a gear body 20 and a ring magnet 21. The gear body 20 forms a rotating shaft 20b on the surface side of a thickness direction opposing the circuit board 13, an outer diameter of the rotating shaft conforming to an inner diameter of a ring shape of the ring magnet 21. The ring magnet 21 is fixed to the gear body 20 by fitting the rotating shaft 20b of the gear body 20 into the inside of a ring and rotates around a central axis of rotation 19 together with rotation of the gear body 20. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a rotation detection device that detects a rotation angle of a detected rotating body. In particular, the present invention relates to a rotation detection device that is small (thin), can form a circuit board wiring pattern with few restrictions, and can reduce the influence of sliding wear on the circuit.

  Conventionally, as a rotation detection device (rotation sensor), by combining a magnet fixed to a rotating body and a magnetic detector for detecting the strength of magnetism, the rotating body is rotated together with the magnet with respect to the magnetic detector. An apparatus configured to detect a rotation angle has been developed and used in the field of steering wheels and the like.

  For example, in Patent Document 1, only one end surface portion of the disk-shaped rotating body is pivotally supported, and the other end surface portion is slidably contacted with the circuit board, and the rotation detecting element is disposed on the rotation center of the disk-shaped rotating body. By avoiding vibrations associated with the rotation of the disk-shaped rotator, the rotation detection accuracy is improved, and an annular contact portion is formed on the other end surface of the disk-shaped rotator so as to surround the rotation detection element. There has been proposed a rotation detection device that achieves a reduction in thickness and size by sliding an annular contact portion on a circuit board.

Patent Document 2 proposes a rotation angle sensor that suppresses vibration of the substrate and does not require a hole in the substrate by forming a space between the substrate and the holding unit and the detection rotating body. .
JP 2000-283704 A JP 2006-98357 A

  However, in the rotation detection devices (rotation sensors) described in Patent Document 1 and Patent Document 2, a rotation detection element is arranged on the rotation center of a disk-shaped rotating body provided with a rotation center magnet so as to face the magnet. Since the annular contact portion is slidably contacted with the circuit board so as to surround the rotation detection element, it is affected by the sliding wear caused by the annular contact portion of the disk-shaped rotating body around the rotation detection element, that is, the sliding contact. There is a problem that the wiring pattern configuration on the circuit board is restricted by the occurrence of cutting or the like of the wiring pattern due to dynamic wear. That is, there is a problem that the area where the wiring pattern cannot be created becomes large.

  In addition, it has at least a total thickness of the rotation detecting element and the magnet in a direction (thickness direction) parallel to the rotation center axis of the disk-shaped rotating body, and is perpendicular to the rotation center axis of the disk-shaped rotating body. There is also a problem that the rotation detection device has a size that at least encloses the rotation detection element in the direction (radial direction) in which the rotation is detected.

  The present invention has been made to solve the above-described problems, and is a small (thin) and low-constraint circuit board wiring pattern, and has less influence on the circuit due to sliding wear. An object of the present invention is to provide a rotation detection device capable of performing the above.

The following invention is provided to solve the above-mentioned conventional problems.
A rotation detection device according to a first aspect of the present invention is a rotation detection device housed in a housing that detects a rotation angle of a first rotating body based on a signal,
A second rotating body that rotates in conjunction with the first rotating body;
A ring-shaped magnet having a rotation center axis common to the second rotating body and rotating together with the second rotating body;
A magnetic detector that outputs a signal of an amount of electricity based on the strength of the magnetic field of the magnet;
A circuit board for processing a signal from the magnetic detection unit;
With
The second rotating body has a rotating shaft portion at the center of rotation, and the rotating shaft portion is disposed so as to penetrate the opening of the ring-shaped central portion of the magnet ,
The circuit board is disposed between one end surface of the rotating shaft portion and an inner wall of the upper portion of the housing, and is fixed to the housing.
The magnetic detection unit is fixed to the circuit board,
The other end face of the rotating shaft is rotatably held on the inner wall of the lower part of the housing,
The second rotating body and the circuit board are held by the same housing member among the housing members constituting the housing .

  With such a configuration, it is possible to reduce a region that is restricted by a wiring pattern on the circuit board. Also, the wiring pattern can be formed on a circuit board that is less affected by sliding wear.

  The rotation detection device according to the second aspect of the present invention is the rotation detection device according to the first aspect of the present invention, wherein one end face of the rotation shaft portion is in contact with the circuit board and is rotatably held. It is characterized by.

  With such a configuration, it is possible to reduce a region that is restricted by a wiring pattern on the circuit board. Also, the wiring pattern can be formed on a circuit board that is less affected by sliding wear.

  A rotation detection device according to a third aspect of the present invention is the rotation detection device according to the first aspect of the present invention, and has a holding member that abuts one end surface of the rotation shaft portion and holds the rotation shaft rotatably. A space is formed between the holding member, the rotating shaft portion, and the circuit board.

With such a configuration, it is possible to further reduce a region that is restricted by the wiring pattern on the circuit board. Also, the wiring pattern can be formed on a circuit board that is less affected by sliding wear. In addition, the circuit board does not receive vibration due to the rotation of the second rotating body, and a more accurate rotation angle can be detected.

  A rotation detection device according to a fourth aspect of the present invention is the rotation detection device according to any one of the first to third aspects of the present invention, wherein the magnetic detection unit is arranged outside the magnet in the radial direction of the magnet. It is characterized by being arranged in.

  With such a configuration, it is possible to configure a rotation detection device that is smaller (thin) and more compact.

  The rotation detection device according to a fifth aspect of the present invention is the rotation detection device according to the fourth aspect of the present invention, wherein the magnetic detection detects the strength of the magnet so as to face the outer surface of the magnet. The detection surface of a part is arrange | positioned.

  With such a configuration, it is possible to configure a rotation detection device that is smaller (thin) and more compact.

The rotation detection device according to a sixth aspect of the present invention is the rotation detection device according to the fourth aspect of the present invention, wherein the detection surface of the magnetic detection unit that detects the strength of the magnet is a surface of the circuit board. It is arrange | positioned on the said circuit board so that it may become parallel.

  With such a configuration, it is possible to configure a rotation detection device that is smaller (thin) and more compact.

  A rotation detection device according to a seventh aspect of the present invention is the rotation detection device according to any one of the first to sixth aspects of the present invention, wherein the second rotation body is interlocked with the first rotation body. And the gear portion is arranged outside the magnet in the radial direction of the magnet.

  With such a configuration, it is possible to configure a rotation detection device that is smaller (thin) and more compact.

  The rotation detection device according to an eighth aspect of the present invention is the rotation detection device according to any one of the first to seventh aspects of the present invention, wherein the first rotating body rotates in conjunction with a steering shaft, In addition, the circuit board is disposed on the steering side with respect to the second rotating body.

With such a configuration, the circuit board is configured not to receive vibration due to the rotation of the second rotating body, and a more accurate rotation angle can be detected.

  A rotation detection device according to a ninth aspect of the present invention is the rotation detection device according to any one of the first to eighth aspects of the present invention, wherein the magnetic detection unit is a Hall element.

According to the present invention, it is possible to reduce a region on a circuit board that is restricted by a wiring pattern. Also, the wiring pattern can be formed on a circuit board that is less affected by sliding wear. In addition, the circuit board does not receive vibration due to the rotation of the second rotating body, and a more accurate rotation angle can be detected. In addition, it is possible to configure a rotation detection device that is smaller (thin) and more compact.

  An embodiment of the present invention will be described with reference to the drawings. In addition, embodiment described below is for description and does not limit the scope of the present invention. Accordingly, those skilled in the art can employ embodiments in which each or all of these elements are replaced by equivalents thereof, and these embodiments are also included in the scope of the present invention.

  FIG. 1 is a cross-sectional view showing an example of a rotation detection device 10 to which the present invention can be applied. FIG. 2 is a part of a cross-sectional view showing a state in which the rotation detection device 10 of FIG. Hereinafter, the rotation detection device 10 is referred to as a rotation sensor 10.

  As shown in FIG. 1, the rotation sensor 10 includes an upper housing 11, a lower housing 12, a circuit board 13, a hall element 14, a first rotating body 15, and a second rotating body 16. As shown in FIG. 2, the first rotating body 15 is a ring-shaped gear, and the steering shaft 90 is fixed inside the ring shape, and rotates in conjunction with the rotation of the steering shaft 90.

  The second rotating body 16 is composed of a gear main body 20 and a ring-shaped magnet 21, and the tooth portion 15 a of the first rotating body 15 and the tooth portion 20 a of the gear main body portion 20 are engaged with each other. It rotates in conjunction with the rotation. That is, the second rotating body 16 rotates around the rotation center axis 19 in conjunction with the rotation around the rotation center axis 91 of the steering shaft 90. Further, the gear main body 20 and the ring-shaped magnet 21 excluding the tooth portion 20 a have substantially the same cross-sectional shape on the plane including the rotation center axis 19 on the entire circumference around the rotation center axis 19.

  The gear main body 20 faces the circuit board 13 in a direction parallel to the rotation center axis 19 (hereinafter referred to as a thickness direction) with the rotation shaft portion 20 b having an outer diameter that matches the ring-shaped inner diameter of the ring-shaped magnet 21. It is formed on the surface side. A fitting shaft portion 20c that fits and rotates with the lower housing 12 is formed on the side opposite to the surface on which the rotating shaft portion 20b is formed.

  The ring-shaped magnet 21 is fixed to the gear main body 20 by fitting the rotation shaft portion 20 b of the gear main body portion 20 inside the ring, and rotates around the rotation center shaft 19 as the gear main body portion 20 rotates.

  The hall element 14 is arranged so as to be outside the outer peripheral position of the ring-shaped magnet 21 in a direction (hereinafter referred to as a radial direction) perpendicular to the rotation center axis 19, and is fixed to the circuit board 13. Here, the detection surface (magnetic sensitive surface) for detecting magnetism is disposed so as to face the outer surface of the ring-shaped magnet 21.

  The lower housing 12 is formed with a circular rotary bearing recess 12a on the bottom surface of the inner wall parallel to the radial direction. By fitting the fitting shaft portion 20c of the gear main body portion 20 into the rotation bearing concave portion 12a, the second rotating body 16 is rotatably supported. In addition, the inner side surface shape of the rotary bearing recess 12 a is a shape in which a cross-sectional shape on a plane including the rotation center shaft 19 is substantially equal on the entire circumference around the rotation center shaft 19.

  The circuit board 13 is fixed to the lower housing 12 and slidably contacts the end surface of the rotating shaft portion 20b of the gear main body portion 20.

  By using the rotation sensor 10 as described above, the area of the end surface of the rotation shaft portion 20b of the gear main body portion 20 that contacts the circuit board 13 is made as small as possible (best supported by a point), so that the second rotation body 16 The area of the circuit board 13 that is affected by sliding wear due to rotation can be reduced. That is, it is possible to reduce a region on the circuit board 13 that is restricted by the wiring pattern.

  Further, by disposing the Hall element 14 so as to face the outer surface of the ring-shaped magnet 21, it is not necessary to consider the thickness of the Hall element 14 in the size of the rotation sensor 10, and the thickness can be further reduced.

  In addition, as shown in FIG. 2, when the circuit board 13 is arranged on the steering 95 side of the second rotating body 16, that is, the rotation shaft part 20 b of the gear main body part 20 in contact with the circuit board 13 is Since it is positioned vertically upward from the position where the tooth portion 15a of the first rotating body 15 and the tooth portion 20a of the gear main body portion 20 are engaged with each other, it is less susceptible to vibration of the gear main body portion 20 of the second rotating body 16. It has become. Therefore, a more accurate rotation angle can be detected.

  FIG. 3 is a cross-sectional view showing an example of another rotation detection device 30 to which the present invention can be applied. As shown in FIG. 3, the rotation sensor 30 (the rotation detection device 30) includes an upper housing 31, a lower housing 32, a circuit board 33, a hall element 34, a first rotating body 35 and a second rotating body 36, and a rotating shaft 37. It has. The first rotating body 35 is a ring-shaped gear, and like the rotation sensor 10, the steering shaft 90 is fixed inside the ring shape, and rotates in conjunction with the rotation of the steering shaft 90.

  The second rotating body 36 includes a gear main body 40 and a ring-shaped magnet 41, and the teeth 35 a of the first rotating body 35 and the teeth 40 a of the gear main body 40 are engaged with each other. It rotates in conjunction with the rotation. That is, the second rotating body 36 rotates around the rotation center axis 39 in conjunction with the rotation around the rotation center axis 91 of the steering shaft 90. The gear main body 40 and the ring-shaped magnet 41 excluding the tooth portion 40 a have substantially the same cross-sectional shape on the plane including the rotation center axis 39 on the entire circumference around the rotation center axis 39.

  The gear main body 40 has a ring shape, the inner diameter of the gear main body 40 matches the outer diameter of the ring-shaped magnet 41, and the thickness of the gear main body 40 is equal to or less than the thickness of the ring-shaped magnet 41. The outer surface of the ring-shaped magnet 41 and the inner surface of the gear main body 40 are fitted to each other. Here, the thickness of the gear main body 40 and the thickness of the ring-shaped magnet 41 are substantially matched. Thereby, the ring-shaped magnet 41 is fixed to the gear main body 40.

  The rotary shaft 37 is fitted so that the outer diameter matches the inner diameter of the ring-shaped magnet 41 and penetrates the inner side of the ring-shaped magnet 41. Further, one end portion 37 a of the rotating shaft 37 abuts on the circuit board 33 and slides, and the other end portion 37 b rotates by being fitted to the lower housing 32. As a result, the rotation shaft 37 is rotated together with the gear body 40 and the ring-shaped magnet 41 around the rotation center shaft 39. In other words, the second rotating body 36 and the rotating shaft 37 are integrally rotated around the rotation center shaft 39. Further, the rotary shaft 37 has a shape in which a cross-sectional shape on a plane including the rotation center axis 39 is substantially equal on the entire circumference around the rotation center axis 39.

  The hall element 34 is disposed outside the outer peripheral position of the gear main body 40 in the radial direction, and is fixed to the circuit board 33. Further, here, the magnetosensitive surface is disposed so as to face the outer surface of the ring-shaped magnet 41 with the gear main body 40 interposed therebetween.

The lower housing 32 is formed with a circular rotary bearing recess 32a on the bottom surface of the inner wall parallel to the radial direction. By fitting the other end 37b of the rotating shaft 37 into the rotating bearing recess 32a, the rotating shaft 37 integrated with the second rotating body 36 is rotatably supported. In addition, the inner side surface shape of the rotary bearing recess 32 a is such that the cross-sectional shape on the plane including the rotation center shaft 39 is substantially equal to the entire circumference around the rotation center shaft 39. The circuit board 33 is fixed to the lower housing 32. The end surface 37a of the rotating shaft 37 is slidably in contact with the end surface.

  By the rotation sensor 30 as described above, the area of the end surface of the one end portion 37a of the rotating shaft 37 that contacts the circuit board 33 is made as small as possible (best supported by a point), so that it is integrated with the rotating shaft 37. The area of the circuit board 33 that is affected by the sliding wear caused by the rotation of the second rotating body 36 can be reduced. That is, it is possible to reduce the area on the circuit board 33 that is restricted by the wiring pattern.

Further, by disposing the Hall element 34 so as to face the outer surface of the ring-shaped magnet 41 through the gear main body 40, the thickness of the Hall element 14 and the thickness of the gear main body 40 are adjusted to the size of the rotation sensor 30. Therefore, it is not necessary to consider this, and the thickness can be further reduced.

  Similarly to the rotation sensor 10, the rotation sensor 30 is configured such that the circuit board 33 is disposed closer to the steering 95 than the second rotating body 36, that is, one end portion 37 a of the rotating shaft 37 that contacts the circuit board 33. However, since it is positioned vertically upward from the position where the tooth portion 35a of the first rotating body 35 meshes with the tooth portion 40a of the gear main body portion 40, the gear main body portion 40 of the second rotating body 36 is more susceptible to vibration. It has a difficult structure. Therefore, a more accurate rotation angle can be detected.

Further, in the rotation sensor 30 described above, the Hall element 34, but through the gear main body portion 40 are disposed so as to face the outer surface of the ring-shaped magnet 41, as shown in FIG. 4, the Hall element 34 The surface mounting may be performed on the circuit board 33 so as to be outside the outer peripheral position of the gear main body 40 in the radial direction.

  FIG. 5 is a cross-sectional view showing an example of another rotation detection apparatus 50 to which the present invention can be applied. As shown in FIG. 5, the rotation sensor 50 (rotation detection device 50) includes an upper housing 51, a lower housing 52, a circuit board 53, a hall element 54, a first rotating body 55, a second rotating body 56, and a holding member 57. I have. The first rotating body 55 is a ring-shaped gear, and like the rotation sensor 10, the steering shaft 90 is fixed inside the ring shape, and rotates in conjunction with the rotation of the steering shaft 90.

  The second rotating body 56 includes a gear main body 60 and a ring-shaped magnet 61, and the tooth portion 55 a of the first rotating body 55 and the tooth portion 60 a of the gear main body 60 are engaged with each other. It rotates in conjunction with the rotation. That is, the second rotating body 56 rotates around the rotation center axis 59 in conjunction with the rotation around the rotation center axis 91 of the steering shaft 90. Further, the gear main body 60 and the ring-shaped magnet 61 excluding the tooth portion 60 a have substantially the same cross-sectional shape on the plane including the rotation center shaft 59 on the entire circumference around the rotation center shaft 59.

  The gear main body 60 has a ring shape, and a rotating shaft portion 60 b having an outer diameter that matches the inner diameter of the ring-shaped magnet 61 is formed on the surface facing the circuit board 13 in the thickness direction. Further, a fitting shaft portion 60c that fits and rotates in the lower housing 52 is formed on the side opposite to the surface on which the rotation shaft portion 60b is formed.

  The ring-shaped magnet 61 is fixed to the gear main body 60 by fitting the rotation shaft 60 b of the gear main body 60 inside the ring, and rotates around the rotation center shaft 59 as the gear main body 60 rotates.

  The hall element 54 is disposed outside the outer peripheral position of the ring-shaped magnet 61 in the radial direction, and is fixed to the circuit board 53. In addition, here, the magnetosensitive surface is disposed so as to face the outer surface of the ring-shaped magnet 61.

  The lower housing 52 is formed with a rotary bearing concave portion 52a and a rotary shaft pressing convex portion 52b on the bottom surface of the inner wall parallel to the radial direction. The rotary shaft pressing convex portion 52 b is formed so that the outer diameter matches the inner diameter of the ring shape of the gear main body portion 60 and can be fitted inside the ring of the gear main body portion 60.

  The rotation bearing recess 52a is formed in an annular shape so that the fitting shaft 60c of the gear body 60 is fitted when the gear body 60 is fitted into the rotation shaft pressing projection 52b. The second rotating body 56 is rotatably supported by fitting the fitting shaft portion 60c of the gear main body portion 60 to the rotation bearing concave portion 52a and the rotation shaft pressing convex portion 52b.

  Moreover, the holding member 57 which contacts the end surface of the rotating shaft part 60b of the gear main-body part 60 fitted in the upper end part of the rotating shaft pressing convex part 52b is provided. The holding member 57 is ring-shaped, formed so that the inner diameter thereof matches the outer diameter of the rotary shaft pressing convex portion 52b, and fitted into the upper end portion of the rotary shaft pressing convex portion 52b, so that the gear body is already fitted. The rotating shaft part 60b of the part 60 is held.

  Further, the inner side surface shape of the rotation bearing recess 52 a and the rotation shaft pressing protrusion 52 b have substantially the same cross-sectional shape on the plane including the rotation center shaft 59 in the entire circumference around the rotation center shaft 59. The circuit board 53 is fixed to the lower housing 52.

  With the rotation sensor 50 as described above, there is no rotating body in contact with the circuit board 53, and the area of the circuit board 53 that is affected by the sliding wear caused by the rotation of the second rotating body 56 can be eliminated. That is, it is possible to eliminate a region on the circuit board 33 that is restricted by the wiring pattern.

  Further, since there is no rotating body that comes into contact with the circuit board 53, the gear body 60 of the second rotating body 56 is not subjected to vibration. Therefore, a more accurate rotation angle can be detected.

  Further, by disposing the Hall element 54 so as to face the outer surface of the ring-shaped magnet 61, it is not necessary to consider the thickness of the Hall element 54 in the size of the rotation sensor 50, and the thickness can be reduced.

Example 1
In Example 1, the wiring pattern restriction area on the circuit board when the rotation sensor (rotation detection device) of the present invention is used is compared with the wiring pattern restriction area on the circuit board when the conventional rotation sensor is used. did. Here, the wiring pattern constrained area is an area area on the circuit board in which the wiring pattern cannot be formed due to sliding of the rotating body (including an area affected by sliding wear).

  As Example 1, the calculation result of the wiring pattern restriction area when the rotation sensor 10 shown in FIG. 1 is used is shown. It is assumed that the rotation shaft portion 20b of the gear body 20 that contacts the circuit board 13 in the rotation sensor 10 is supported by a point. In consideration of normal safety, a width of 1 mm on the inside and outside of the sliding portion is used as a pattern forbidden band (safety band).

  Therefore, in the rotation sensor 10, the wiring pattern restriction area is only a safety band due to sliding of the rotation shaft portion 20 b of the gear main body portion 20. That is, since the sliding portion is a point, a circle having a diameter of 1 mm is a safety zone, and the wiring pattern restriction area S1 is expressed by the following equation.

S1 = 2π × 0.5 ² (mm ² ) ≈1.57 (mm ² )
As Comparative Example 1, a calculation result of the wiring pattern restriction area when the rotation sensor 100 described in Patent Document 1 is used is shown. FIG. 6 is a cross-sectional view showing a configuration of a conventional rotation detection device 100 (described in Patent Document 1). As shown in FIG. 6, a driven gear (disk-shaped rotating body) 101 is rotatably supported by a circular bearing recess 103 provided in the lower housing 102. In addition, a disk-shaped magnet 104 is fitted to the rotation center portion of the driven gear 101. The magnetoresistive element (rotation detecting element) 105 is located on the rotation center of the driven gear 101.

  A circular fitting shaft portion 106 to be fitted into the circular bearing recess 103 is formed on one end surface portion of the driven gear 101, and an annular contact portion 108 is formed on the other end surface portion so as to surround the holding hole 107. Is formed. The annular contact portion 108 is in contact with one surface side of the circuit board 109 and surrounds the magnetoresistive element (rotation detecting element) 105. In the circuit board 109 in contact with the driven gear 101, the sliding width of the sliding portion having a diameter of 10 mm is assumed to be 1 mm. In consideration of normal safety, a width of 1 mm on the inside and outside of the sliding portion is used as a pattern forbidden band (safety band).

  Therefore, as shown in FIG. 7, in the rotation sensor 100, the wiring pattern restriction area S2 has an area S21 of a sliding portion having a diameter of 10 mm and a width of 1 mm, and a width of 1 mm on the inner and outer sides of the sliding portion. It is the sum (S2 = S21 + S22) with the area S22 of the safety zone.

  The area S21 of the sliding part is an area of a ring shape having a width of 0.5 mm and the diameter of a circle passing through the center of the width is 10 mm, and the area S22 of the safety belt is 0. 0 mm on the inner side of the sliding part. This is the sum of a ring-shaped area S221 inscribed with a width of 5 mm and a ring-shaped area S222 circumscribed with a width of 0.5 mm on the outside of the sliding portion.

Therefore, the wiring pattern constraint area S2 is expressed by the following equation.
S2 = 2π × (5.75 ² −4.25 ² ) (mm ² ) ≈94.25 (mm ² )
When Example 1 and Comparative Example 1 are compared, the wiring pattern restriction area S2 of Comparative Example 1 is about 60 times the wiring pattern restriction area S1 of Example 1, and by using the rotation sensor 10 of the present invention, wiring It was found that the pattern constrained area can be greatly reduced.

(Example 2)
In Example 2, the thickness of the rotation sensor when the rotation sensor (rotation detection device) of the present invention was used was compared with the thickness of the rotation sensor when the conventional rotation sensor was used.

  As Example 2, the calculation result of the thickness of the rotation sensor 30 when the rotation sensor 30 shown in FIG. 3 is used is shown. In the rotation sensor 30, the thickness of the upper housing 31 is 2 mm, the thickness of the circuit board 33 is 1 mm, the thickness of the ring magnet 41 is 2 mm, the space for sliding is 2 mm, and the thickness of the lower housing 32 is 1 mm. Then, the thickness of the rotation sensor 30 is 8 mm.

  As Comparative Example 2, the calculation result of the thickness of the rotation sensor 100 when the rotation sensor 100 described in Patent Document 1 shown in FIG. 6 is used is shown. In the rotation sensor 100, the upper housing 110 has a thickness of 2 mm, the circuit board 109 has a thickness of 1 mm, the magnetoresistive element 105 has a thickness of 2 mm, the disk-shaped magnet 104 has a thickness of 2 mm, and a space for sliding. When the thickness of the lower housing 102 is 2 mm and the thickness of the lower housing 102 is 1 mm, the thickness of the rotation sensor 100 is 10 mm.

  When Example 2 and Comparative Example 2 are compared, the thickness of the rotation sensor 100 of Comparative Example 2 is 2 mm thicker than the thickness of the rotation sensor 30 of Example 2, and by using the rotation sensor 30 of the present invention, It was found that the thickness of the rotation sensor can be further reduced.

It is sectional drawing which shows an example of the rotation detection apparatus 10 which can apply this invention. FIG. 2 is a part of a cross-sectional view showing a state in which the rotation detection device 10 of FIG. It is sectional drawing which shows an example of another rotation detection apparatus 30 which can apply this invention. It is sectional drawing which shows the modification of the rotation detection apparatus 30 shown in FIG. It is sectional drawing which shows an example of another rotation detection apparatus 50 which can apply this invention. It is sectional drawing which shows the structure of the conventional rotation detection apparatus 100. FIG. It is a figure for demonstrating the wiring pattern restrictions area in the conventional rotation sensor 100. FIG.

Explanation of symbols

10, 30, 50 Rotation sensor (Rotation detection device)
11, 31, 51 Upper housing 12, 32, 52 Lower housing 13, 33, 53 Circuit board 14, 34, 54 Hall element 15, 35, 55 First rotating body 16, 36, 56 Second rotating body 20, 40, 60 Gear body 21, 41, 61 Ring-shaped magnet 20b Rotating shaft 20c Fitting shaft 12a Rotating bearing recess
37 rotating shaft 56 holding member 90 steering shaft

Claims (9)

A rotation detection device housed in a housing for detecting a rotation angle of a first rotating body based on a signal,
A second rotating body that rotates in conjunction with the first rotating body;
A ring-shaped magnet having a rotation center axis common to the second rotating body and rotating together with the second rotating body;
A magnetic detector that outputs a signal of an amount of electricity based on the strength of the magnetic field of the magnet;
A circuit board for processing a signal from the magnetic detection unit;
With
The second rotating body has a rotating shaft portion at the center of rotation, and the rotating shaft portion is disposed so as to penetrate the opening of the ring-shaped central portion of the magnet,
The circuit board is disposed between one end surface of the rotating shaft portion and an inner wall of the upper portion of the housing, and is fixed to the housing.
The magnetic detection unit is fixed to the circuit board,
The other end face of the rotating shaft is rotatably held on the inner wall of the lower part of the housing,
The rotation detecting device, wherein the second rotating body and the circuit board are held by the same housing member among the housing members constituting the housing.   The rotation detection device according to claim 1, wherein one end surface of the rotation shaft portion is in contact with the circuit board and is rotatably held. A holding member that abuts one end face of the rotating shaft portion and holds it rotatably;
The rotation detection device according to claim 1, wherein a space is formed between the holding member, the rotation shaft portion, and the circuit board.   4. The rotation detection device according to claim 1, wherein the magnetism detection unit is disposed outside the magnet in a radial direction of the magnet. 5.   The rotation detection device according to claim 4, wherein a detection surface of the magnetic detection unit that detects the strength of the magnet is disposed so as to face the outer surface of the magnet. Detecting surface of the magnetic detection unit for detecting the intensity of the magnets, so as to be parallel to the plane of the circuit board, rotating according to claim 4, characterized in that it is arranged on the circuit board Detection device. The second rotating body has a gear portion that rotates in conjunction with the first rotating body,
The rotation detection device according to claim 1, wherein the gear portion is disposed outside the magnet in a radial direction of the magnet.   The first rotating body rotates in conjunction with a steering shaft, and the circuit board is disposed closer to the steering side than the second rotating body. The rotation detection device according to item.   The rotation detection device according to claim 1, wherein the magnetic detection unit is a Hall element.

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