JP2009236722A - Rotating angle detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the degradation of detection precision accompanying displacement of a rotor 3 in a rotating angle detector 1 for composing part of a magnetic circuit by the rotor 3 integrally rotated with a rotating shaft 2 and detecting a magnetic flux changed in response to a rotating angle of the rotating shaft 2. <P>SOLUTION: The rotating angle detector fixes first and second stators 5, 6 on both the sides of an axial direction of the rotor 3, and forms first and second axial air gaps a1, a2 between the rotor 3 and the first and second stators 5, 6. In addition, the rotating angle detector includes an axial protrusion 13 opposite to a radial direction to the stator 5 by being projected to one direction side of an axial direction on the outer peripheral side of the first stator 5 on the rotor 3 and forms a radial air gap b between the axial protrusion 13 and the first stator 5. Thereby the rotating angle detector prevents the degradation of detection precision by hardly generating large variation for detection precision of the rotor 3 even when the rotor 3 displaces in any one direction of an axial or radial direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotation angle detection device that detects a rotation angle of a rotary shaft such as a valve shaft.

  Conventionally, in a rotation angle detection device, a part of a magnetic circuit is constituted by a rotating body that rotates integrally with a rotation shaft, and a magnetic flux that changes according to the rotation angle of the rotation shaft is detected by a magnetic flux detection means such as a Hall element. A device that detects the rotation angle by detection is known, and is used, for example, to detect the rotation angle of various valve bodies such as a throttle valve. That is, according to this rotation angle detection device, the fixed body that passes the magnetic flux in the axial direction is provided to the rotating body, and the magnetic flux transferred between the fixed body and the rotating body changes according to the rotation angle. To do. And a rotation angle detection apparatus detects a rotation angle by detecting this magnetic flux.

  For example, according to the rotation angle detection device 100 </ b> A of Patent Document 1, as shown in FIG. 5, the magnet 101 is provided in a disc shape, and the magnet 101 itself forms the rotating body 102. The magnet 101 is magnetized with different magnetism on one axial side and the other axial side, and the fixed body 103 is arranged so as to face the magnet 101 on both sides in the axial direction with the magnet 101 sandwiched in the axial direction. ing.

  As a result, the opposing area in the axial direction between the rotating body 102 (magnet 101) and the fixed body 103 changes according to the rotation angle of the rotating body 102, so that the magnetic flux transferred between the magnet 101 and the fixed body 103 Also changes according to the rotation angle. For this reason, the rotation angle detection device 100 </ b> A can detect the rotation angle by detecting the magnetic flux by the magnetic flux detection means 104.

  Further, according to the rotation angle detection device 100B of Patent Document 2, as shown in FIG. 6, the magnet 101 is arranged so that different magnetism appears at both ends of the semicircular arc-shaped fixed body 103, and two magnets 101 Protrusions 105 are provided therebetween, and magnetic flux detection means 104 is disposed on the protrusions 105. The rotating body 102 is provided in a plate-shaped sector, and is arranged so as to be able to rotate while maintaining a predetermined distance in the axial direction between the magnet 101 and the magnetic flux detecting means 104.

  As a result, the circumferential distance between the magnet 101 and the rotating body 102 changes according to the rotation angle of the rotating body 102, so that the magnetic flux transferred between the magnet 101 and the protrusion 105 via the rotating body 102 also rotates. It changes according to the corner. For this reason, the rotation angle detection device 100B can detect the rotation angle by detecting the magnetic flux.

  However, in each of the rotation angle detection devices 100A and 100B, the positional deviation of the rotating body 102 greatly affects the detection accuracy, and the robustness is low. The positional deviation of the rotating body 102 is inevitably generated due to the dimensional tolerance of each component, the backlash of the rotating shaft, and the like. The inevitable positional deviation of the rotating body 102 causes the rotation angle detection devices 100A and 100B to be displaced. Detection accuracy is necessarily affected.

  That is, according to the rotation angle detection device 100A, when the rotating body 102 (magnet 101) is displaced in the radial direction, the facing area in the axial direction between the rotating body 102 and the fixed body 103 varies. For this reason, the magnetic flux transferred between the rotating body 102 and the fixed body 103 also fluctuates, and the detected value of the rotation angle includes an error due to a positional deviation.

  According to the rotation angle detection device 100A, even if the rotating body 102 is displaced in the axial direction, the axial air gap between the rotating body 102 and the fixed body 103 on one side in the axial direction and the rotation on the other side in the axial direction. The sum of the axial air gap between the body 102 and the fixed body 103 is unchanged. For this reason, even if the rotating body 102 is displaced in the axial direction, the magnetic flux transferred between the rotating body 102 and the fixed body 103 does not fluctuate, and the detected value of the rotation angle does not include an error.

  Further, according to the rotation angle detection device 100B, when the rotating body 102 is displaced in the radial direction, the circumferential distance between the magnet 101 and the rotating body 102 varies. For this reason, the magnetic flux transferred between the magnet 101 and the projection 105 via the rotating body 102 also fluctuates, and the detected value of the rotation angle includes an error due to the positional deviation.

Furthermore, according to the rotation angle detection device 100B, when the rotating body 102 is displaced in the axial direction, the axial distance between the magnet 101 and the rotating body 102 and the axial distance between the magnetic flux detecting means 104 and the rotating body 102 are as follows. fluctuate. For this reason, even when the rotating body 102 is displaced in the axial direction, the detected value of the rotation angle includes an error associated with the displacement.
JP 2006-38872 A Japanese Patent Laid-Open No. 9-236644

  The present invention has been made in order to solve the above-described problems. The object of the present invention is to form a part of a magnetic circuit by a rotating body that rotates integrally with a rotating shaft, and to adjust the rotation angle of the rotating shaft. An object of the present invention is to suppress a decrease in detection accuracy caused by a displacement of a rotating body in a rotation angle detection device that detects a magnetic flux that changes in response.

[Means of Claim 1]
The rotation angle detection device according to claim 1 is configured to rotate integrally with a predetermined rotation shaft and pass a magnetic flux, and is arranged coaxially with the rotation shaft and fixed to one side in the axial direction of the rotation body. A first fixed air gap that forms a first axial air gap with the rotating body and allows the magnetic flux to pass through, and a second axial air gap that is fixed to the other axial side of the rotating body and is fixed to the rotating body And a magnetic flux detecting means for detecting the magnetic flux passed between the first stationary body and the second stationary body via the rotating body.

  The rotating body has an axially bulging portion that bulges on one side in the axial direction on the outer peripheral side of the first fixed body and faces the first fixed body in the radial direction. A radial air gap is formed with the fixed body.

  As a result, even if the rotating body is displaced in the axial direction and the first and second axial air gaps change, the sum of the first and second axial air gaps remains unchanged. For this reason, even if the rotating body is displaced in the axial direction, the magnetic flux transferred between the first and second fixed bodies via the rotating body does not fluctuate. There is no effect.

  When the rotating body is displaced in the radial direction, the opposing area in the axial direction between the rotating body and the first and second fixed bodies varies, but the radial air between the axially bulging portion and the first fixed body varies. The gap also increases or decreases (hereinafter, the opposing area in the axial direction between the rotating body and the first fixed body is called the first axial facing area, and the opposing area in the axial direction between the rotating body and the second fixed body is the second axial direction. Called the facing area).

For this reason, the fluctuation | variation of the magnetic flux accompanying the fluctuation | variation of the 1st, 2nd axial direction opposing area can be suppressed by increase / decrease in a radial direction air gap. As a result, even if the rotating body is displaced in the radial direction, the fluctuation of the magnetic flux transferred between the first and second fixed bodies is suppressed, and the influence on the detection accuracy is reduced.
As described above, even if the rotating body is displaced in either the axial direction or the radial direction, a large variation in the rotational angle detection accuracy does not occur, and a decrease in detection accuracy is suppressed.

[Means of claim 2]
According to the rotation angle detecting device of the second aspect, the axial bulge portion has a radially extending portion that extends toward the inner peripheral side toward the first fixed body and faces the first fixed body in the radial direction. However, the radial air gap is reduced by the radially extending portion.
Thereby, the opposing area in the radial direction between the rotating body and the first fixed body (hereinafter referred to as the first radial opposing area) is formed by the radial facing between the radial extension portion and the first fixed body. Can do. For this reason, even if the rotating body is displaced in the axial direction, the first radial facing area is less likely to fluctuate, and fluctuations in the magnetic flux delivered in the radial direction between the rotating body and the first fixed body are suppressed. . As a result, the fluctuation of the magnetic flux transferred between the first and second fixed bodies is further suppressed.

[Means of claim 3]
According to the rotation angle detecting device according to claim 3, the other axial end of the radially extending portion is on one axial side than the other axial end of the first fixed body, and the axial direction of the radially extending portion. The axial distance between the other end and the other axial end of the first fixed body is larger than the maximum value assumed as the amount of positional deviation in the axial direction of the rotating body.
Thereby, even if the rotating body is displaced in the axial direction, the radially extending portion and the first fixed body can reliably face each other in the radial direction, and the same first radial facing area can be maintained. Note that the maximum value of the positional deviation amount in each direction can be assumed in advance based on the dimensional tolerance of each component, the backlash of the rotating shaft, and the like.

[Means of claim 4]
According to the rotation angle detection device of the fourth aspect, the first fixed body has a radially extending portion that extends toward the outer peripheral side toward the axially bulging portion and is opposed to the axially bulging portion in the radial direction. However, the radial air gap is reduced by the radially extending portion.
Thereby, a 1st radial direction opposing area can be formed by radial opposing of a radial direction extension part and an axial bulge part. For this reason, even if the rotating body is displaced in the axial direction, the first radial facing area is less likely to fluctuate, and fluctuations in the magnetic flux delivered in the radial direction between the rotating body and the first fixed body are suppressed. . As a result, the fluctuation of the magnetic flux transferred between the first and second fixed bodies is further suppressed.

[Means of claim 5]
According to the rotation angle detecting device of the fifth aspect, the one axial end of the radially extending portion is on the other axial side than the one axial end of the axial bulging portion, and the one axial end of the radially extending portion. And the axial end of the axial bulging portion are larger than the maximum value assumed as the amount of positional deviation in the axial direction of the rotating body.
Thereby, even if the rotating body is displaced in the axial direction, the radially extending portion and the axially bulging portion can be reliably opposed to each other in the radial direction, and the same first radial facing area can be maintained. .

[Means of claim 6]
According to the rotation angle detection device according to claim 6, the rotating body has an axial extending portion that extends in the axial direction toward the first fixed body and faces the first fixed body in the axial direction, The first axial air gap is reduced by the axial extension.
Thereby, a 1st axial direction opposing area can be formed by axial opposing of an axial direction extension part and a 1st fixing body. For this reason, even if the rotating body is displaced in the radial direction, the area facing the first axial direction is less likely to fluctuate, and fluctuations in the magnetic flux transferred in the axial direction between the rotating body and the first fixed body are suppressed. . As a result, the fluctuation of the magnetic flux transferred between the first and second fixed bodies is further suppressed.

[Means of Claim 7]
According to the rotation angle detection device of claim 7, the outer peripheral end of the axially extending portion is located on the inner peripheral side of the outer peripheral end of the first fixed body, and the outer peripheral end of the axially extending portion and the first fixed body. The radial distance from the outer peripheral edge of the rotating body is larger than the maximum value assumed as the positional deviation amount of the rotating body in the radial direction.
Thereby, even if the rotating body is displaced in the radial direction, the axially extending portion and the first fixed body can reliably face each other in the axial direction and maintain the same first axial facing area.

[Means of Claim 8]
According to the rotation angle detection device of the eighth aspect, the first fixed body has an axially extending portion that extends to the other side in the axial direction toward the rotating body and faces the rotating body in the axial direction. The axial air gap is reduced by the axial extension.
Thereby, a 1st axial direction opposing area can be formed by axial opposing of an axial direction extension part and a rotary body. For this reason, even if the rotating body is displaced in the radial direction, the area facing the first axial direction is less likely to fluctuate, and fluctuations in the magnetic flux transferred in the axial direction between the rotating body and the first fixed body are suppressed. . As a result, the fluctuation of the magnetic flux transferred between the first and second fixed bodies is further suppressed.

[Means of Claim 9]
According to the rotation angle detection device of the ninth aspect, the inner peripheral end of the axially extending portion is located on the outer peripheral side with respect to the inner peripheral end of the rotating member, and the inner peripheral end of the axially extending portion and the inner portion of the rotating member are arranged. The radial distance from the peripheral end is larger than the maximum value assumed as the positional deviation amount of the rotating body in the radial direction.
Thereby, even if the rotating body is displaced in the radial direction, the axially extending portion and the rotating body can reliably face each other in the axial direction and maintain the same first axial facing area.

  The rotation angle detection device of the best mode 1 is a rotating body that rotates integrally with a predetermined rotating shaft and allows magnetic flux to pass through, and is arranged coaxially with the rotating shaft and fixed to one side in the axial direction of the rotating body. A first fixed air gap that forms a first axial air gap with the body and allows the magnetic flux to pass through, and is fixed to the other axial side of the rotating body, and a second axial air gap is formed between the rotating body and the first rotating body. A second fixed body that is formed and allows the magnetic flux to pass through; and a magnetic flux detection means that detects a magnetic flux passed between the first fixed body and the second fixed body via the rotating body.

  The rotating body has an axially bulging portion that bulges on one side in the axial direction on the outer peripheral side of the first fixed body and faces the first fixed body in the radial direction. A radial air gap is formed with the fixed body.

  According to the rotation angle detection device of the best mode 2, the axial bulge portion has a radially extending portion that extends toward the first fixed body on the inner peripheral side and faces the first fixed body in the radial direction. The radial air gap is reduced by the radial extension. The other end in the axial direction of the radially extending portion is on one side in the axial direction than the other end in the axial direction of the first fixed body, and the other end in the axial direction of the radially extending portion and the other axial end of the first fixed body. Is larger than the maximum value assumed as the amount of positional deviation in the axial direction of the rotating body.

  In addition, the rotating body extends in one axial direction toward the first fixed body and has an axially extending portion facing the first fixed body in the axial direction, and the first axial air gap extends in the axial direction. It is reduced by the part. The outer peripheral end of the axially extending portion is closer to the inner peripheral side than the outer peripheral end of the first fixed body, and the radial distance between the outer peripheral end of the axially extending portion and the outer peripheral end of the first fixed body is the rotating body. It is larger than the maximum value assumed as the positional deviation amount in the radial direction.

  According to the rotation angle detecting device of the best mode 3, the first fixed body has a radially extending portion that extends toward the outer peripheral side toward the axially bulging portion and faces the axially bulging portion in the radial direction. The radial air gap is reduced by the radial extension. The one end in the axial direction of the radially extending portion is located on the other side in the axial direction from the one end in the axial direction of the axially bulging portion, and the one end in the axial direction of the radially extending portion and the one end in the axial direction of the axially bulging portion are The axial distance is larger than the maximum value assumed as the amount of positional deviation in the axial direction of the rotating body.

  The first fixed body has an axial extension extending in the axial direction toward the rotating body and facing the rotating body in the axial direction, and the first axial air gap is formed by the axial extending section. Has been reduced. The inner peripheral end of the axially extending portion is on the outer peripheral side of the inner peripheral end of the rotating body, and the radial distance between the inner peripheral end of the axially extending portion and the inner peripheral end of the rotating body is It is larger than the maximum value assumed as the positional deviation amount in the radial direction.

[Configuration of Example 1]
A configuration of the rotation angle detection device 1 according to the first embodiment will be described with reference to FIGS. 1 and 2.
The rotation angle detection device 1 constitutes a part of a magnetic circuit by a rotating body 3 that rotates integrally with a rotation shaft 2, and detects a magnetic flux that changes according to the rotation angle of the rotation shaft 2 as a magnetic flux detection means such as a Hall element. The rotation angle is detected by detecting at 4, and is used, for example, to detect the rotation angle of the throttle valve. And the electrical signal output from the rotation angle detection apparatus 1 is input into the electronic control apparatus (not shown) which controls an engine, for example, and is used for various control processes.

  The rotation angle detection device 1 includes a rotating body 3 that rotates integrally with the rotating shaft 2, and a first fixed body 5 that is arranged coaxially with the rotating shaft 2 and fixed to one side in the axial direction of the rotating body 3. Magnetic flux detection for detecting a magnetic flux transferred between the first fixed body 5 and the second fixed body 6 via the rotary body 3 and the second fixed body 6 fixed to the other axial side of the rotary body 3 Means 4 and two magnets 7, 8 are provided.

  The rotating body 3 is provided in a semicircular shape using a magnetic material that passes magnetic flux as a material. The rotating body 3 is attached to, for example, one end of the rotating shaft 2 so that the center of the semicircle is disposed on the axis of the rotating shaft 2. Further, an axially bulging portion 13 that bulges along the outer peripheral edge in an arc shape on one side in the axial direction is provided on one end surface 12 of the rotating body 3.

  The first fixed body 5 is provided in a columnar shape having a diameter smaller than that of the rotating body 3 using a magnetic material that transmits magnetic flux as a material, and is arranged coaxially with the rotating shaft 2. The other end surface 14 of the first fixed body 5 is opposed to the one end surface 12 of the rotating body 3 in the axial direction, and the first fixed body 5 and the rotating body 3 are opposed by the one end surface 12 and the other end surface 14 facing each other. A first axial air gap a1 is formed between the two.

Further, the axial bulging portion 13 bulges in the axial direction on the outer peripheral side of the first fixed body 5 so as to be opposed to the first fixed body 5 in the radial direction. The inner peripheral surface 15 of the first fixed body 5 and the outer peripheral surface 16 of the first fixed body 5 are opposed to each other in the radial direction. A radial air gap b is formed between the first fixed body 5 and the rotating body 3 by facing the inner peripheral surface 15 and the outer peripheral surface 16.
The magnetic flux detection means 4 is fixed to one axial end of the first fixed body 5.

  The second fixed body 6 includes two plate-like bodies 19 and 20 made of a magnetic material that passes magnetic flux. The plate-like bodies 19 and 20 are provided in a semicircular shape having a diameter larger than that of the rotating body 3. Further, the plate-like bodies 19 and 20 are provided with semicircular inner peripheral edges concentric with the outer peripheral edges, and the inner peripheral edges face each other to form a substantially cylindrical hollow. It is arranged to penetrate through.

  Further, the one end face 21 of the plate-like bodies 19 and 20 is disposed so as to be able to face the other end face 22 of the rotating body 3 in the axial direction, and the second fixing is achieved by facing the one end face 21 and the other end face 22. A second axial air gap a <b> 2 is formed between the body 6 and the rotating body 3.

  Further, the second fixed body 6 has a cross-linking structure on one side in the axial direction, and by this cross-linking structure, a magnetic circuit including the first fixed body 5, the rotating body 3, the second fixed body 6, and the magnets 7 and 8. Is formed, and the magnetic flux is transferred between the first fixed body 5 and the second fixed body 6 via the rotating body 3.

  That is, the second fixed body 6 is integrally provided with magnetic bodies 25 and 26 extending from the center of the outer peripheral edge of the plate-like bodies 19 and 20 to one side in the axial direction, and the magnetic bodies 25 and 26 are respectively in the axial direction. It bends at a right angle at one end and extends to the inner periphery. In addition, a magnetic body 29 is arranged coaxially with the first fixed body 5 and the rotary shaft 2 at the same position in the axial direction as the extensions 27 and 28 to the inner peripheral side of the magnetic bodies 25 and 26, and the magnets 7 and 8 are The extension portions 27 and 28 and the magnetic body 29 are sandwiched and fixed in the radial direction.

  The magnets 7 and 8 are provided in a columnar shape, and the magnet 7 is magnetized on the N pole on the outer peripheral side and magnetized on the S pole on the inner peripheral side. Further, the magnet 8 is magnetized to the S pole on the outer peripheral side and magnetized to the N pole on the inner peripheral side. Further, the magnetic flux detection means 4 is sandwiched between the magnetic body 29 and the first fixed body 5 in the axial direction.

[Operation of Example 1]
The operation of the rotation angle detection device 1 according to the first embodiment will be described with reference to FIGS. 1 and 2.
The rotating body 3 of the rotation angle detecting device 1 inevitably has a positional deviation in the axial direction or the radial direction due to the dimensional tolerance of each component, the backlash of the rotating shaft 2 or the like. Then, the rotation angle detection device 1 acts so as to suppress the magnetic flux transferred between the first and second fixed bodies 5 and 6 via the rotating body 3 from being fluctuated due to the positional deviation of the rotating body 3 (hereinafter referred to as “rotating body 3”). The displacement amount in the radial direction of the rotating body 3 is referred to as a radial displacement amount, and the displacement amount in the axial direction of the rotating body 3 is referred to as an axial displacement amount).

  First, when the rotating body 3 is displaced in the axial direction, the first and second axial air gaps a1 and a2 vary, but the sum of the first and second axial air gaps a1 and a2 respectively. Is unchanged (see FIG. 1C). For this reason, even if the rotary body 3 is displaced in the axial direction, the magnetic flux delivered between the first and second fixed bodies 5 and 6 does not fluctuate.

  Further, when the rotating body 3 is displaced in the radial direction, the facing area in the axial direction between the rotating body 3 and the first and second fixed bodies 5 and 6 varies. For example, when the rotating body 3 is displaced to the left side in the drawing (see FIG. 2B), the facing area in the axial direction of the rotating body 3 and the first fixed body 5 (first axial facing area) decreases. The opposing area in the axial direction between the rotating body 3 and the second fixed body 6 (second axially opposing area) increases. Further, when the rotating body 3 is displaced to the right side in the drawing (see FIG. 2C), the first axial direction opposing area increases and the second axial direction opposing area decreases.

  Here, the absolute value of the rate of change of the first and second axial facing areas with respect to the radial deviation is larger in the second axial facing area than in the first axial facing area. For this reason, when the rotating body 3 is displaced to the left in the figure, the total of the first and second axial facing areas increases, and the magnetic flux transferred in the axial direction between the first and second fixed bodies 5 and 6 is increased. To increase. In addition, when the position is shifted to the right side in the figure, the total of the first and second axial facing areas decreases, and the magnetic flux transferred in the axial direction between the first and second fixed bodies 5 and 6 decreases. Thus, when the rotary body 3 is displaced in the radial direction, the magnetic flux delivered in the axial direction between the first and second fixed bodies 5 and 6 will fluctuate.

  In the rotation angle detection device 1, the radial air gap b increases when the rotating body 3 is displaced to the left in the figure with respect to such an axial magnetic flux fluctuation, and therefore, between the first and second fixed bodies 5 and 6. The magnetic flux delivered in the radial direction decreases (see FIG. 2B). Further, when the rotating body 3 is displaced to the right in the figure, the radial air gap b decreases, so that the magnetic flux delivered in the radial direction between the first and second fixed bodies 5 and 6 increases (FIG. 2C). reference).

  For this reason, even if the rotating body 3 is displaced to the left in the figure and the magnetic flux delivered in the axial direction between the first and second fixed bodies 5 and 6 increases, the magnetic flux delivered in the radial direction decreases ( (Refer FIG.2 (b)). Further, even if the rotating body 3 is displaced to the right in the figure and the magnetic flux delivered in the axial direction between the first and second fixed bodies 5 and 6 decreases, the magnetic flux delivered in the radial direction increases (see FIG. 2 (c)). As a result, even if the rotating body 3 is displaced in the radial direction, fluctuations in the entire magnetic flux transferred between the first and second fixed bodies 5 and 6 both in the axial direction and in the radial direction are suppressed.

[Effect of Example 1]
According to the rotation angle detection device 1 of the first embodiment, the first and second fixed bodies 5 and 6 are fixed to both sides in the axial direction of the rotating body 3 that rotates integrally with the rotating shaft 2. The first and second axial air gaps a1 and a2 are formed between the second fixed bodies 5 and 6. The rotating body 3 has an axial bulging portion 13 that bulges on one side in the axial direction on the outer peripheral side of the first fixed body 5 and faces the first fixed body 5 in the radial direction. A radial air gap b is formed between 13 and the first fixed body 5.

  As a result, even if the rotating body 3 is displaced in the axial direction and the first and second axial air gaps a1 and a2 vary, the sum of the first and second axial air gaps a1 and a2 is Is unchanged. For this reason, even if the rotating body 3 is displaced in the axial direction, the magnetic flux transferred between the first and second fixed bodies 5 and 6 via the rotating body 3 does not fluctuate. Misalignment does not affect the detection accuracy.

In addition, when the rotating body 3 is displaced in the radial direction, the first and second axial facing areas vary, but the radial air gap b is a fluctuation of magnetic flux due to the variation of the first and second axial facing areas. Increase or decrease to cancel. For this reason, even if the rotating body 3 is displaced in the radial direction, the fluctuation of the magnetic flux transferred between the first and second fixed bodies 5 and 6 is suppressed, and the influence on the detection accuracy is reduced.
As described above, even if the rotating body 3 is displaced in either the axial direction or the radial direction, a large fluctuation in the rotational angle detection accuracy does not occur, and a decrease in detection accuracy is suppressed.

  According to the rotation angle detection device 1 of the second embodiment, as shown in FIG. 3, the axial bulging portion 13 includes an arc-shaped radial extending portion 32 extending toward the inner peripheral side toward the first fixed body 5. Have. The inner peripheral end 33 of the radial extension part 32 faces the outer peripheral surface 16 of the first fixed body 5 in the radial direction, and the radial air gap b is reduced by the radial extension part 32.

  Thereby, the opposing area in the radial direction between the rotating body 3 and the first fixed body 5 (first radial opposing area) is formed by the radial facing between the radial extending portion 32 and the first fixed body 5. Can do. For this reason, even if the rotating body 3 is displaced in the axial direction, the first radial facing area is less likely to fluctuate, and the fluctuation of the magnetic flux transferred in the radial direction between the rotating body 3 and the first fixed body 5 is changed. It is suppressed. As a result, the fluctuation of the magnetic flux transferred between the first and second fixed bodies 5 and 6 is further suppressed.

Further, the other axial end 34 of the radially extending portion 32 is on one axial side than the other end surface 14 of the first fixed body 5, and the axial distance A1 between the other axial end 34 and the other end surface 14 is It is larger than the maximum value assumed as the amount of axial deviation.
Thereby, even if the rotary body 3 is displaced in the axial direction, the radially extending portion 32 and the first fixed body 5 reliably face each other in the radial direction and maintain the same first radial facing area. Can do. It should be noted that the maximum values of the axial direction deviation amount and the radial direction deviation amount can be assumed in advance based on the dimensional tolerance of each component, the backlash of the rotating shaft 2, and the like.

  The rotating body 3 includes a fan-shaped axially extending portion 36 that extends toward the first fixed body 5 on one side in the axial direction. An axial end 37 of the axially extending portion 36 faces the other end surface 14 of the first fixed body 5 in the axial direction, and the first axial air gap a1 is reduced by the axially extending portion 36. ing.

  Thereby, the first axially opposed area can be formed by axially opposing the axially extending portion 36 and the first fixed body 5. For this reason, even if the rotating body 3 is displaced in the radial direction, the area facing the first axial direction is less likely to fluctuate, and the fluctuation of the magnetic flux transferred in the axial direction between the rotating body 3 and the first fixed body 5 is changed. It is suppressed. As a result, the fluctuation of the magnetic flux transferred between the first and second fixed bodies 5 and 6 is further suppressed.

Further, the outer peripheral surface 38 of the axially extending portion 36 is located on the inner peripheral side with respect to the outer peripheral surface 16 of the first fixed body 5, and the radial distance B1 between the outer peripheral surface 38 and the outer peripheral surface 16 is assumed as the radial deviation amount. Is greater than the maximum value
Thereby, even if the rotating body 3 is displaced in the radial direction, the axially extending portion 36 and the first fixed body 5 reliably face each other in the axial direction and maintain the same first axial facing area. Can do.

  According to the rotation angle detection device 1 of the third embodiment, as shown in FIG. 4, the first fixed body 5 extends toward the outer peripheral side toward the axial bulging portion 13 and the other axial direction toward the rotary body 3. It has an annular extension 40 extending to the side. The outer peripheral surface 41 of the extending portion 40 faces the inner peripheral surface 15 of the axial bulging portion 13 in the radial direction, and the radial air gap b is reduced by the extending portion 40. That is, the extending portion 40 has a function similar to that of the radially extending portion 32 of the second embodiment.

  Thus, the first radial facing area can be formed by the radial facing of the extending portion 40 and the axial bulging portion 13. For this reason, even if the rotating body 3 is displaced in the axial direction, the first radial facing area is less likely to fluctuate, and the fluctuation of the magnetic flux transferred in the radial direction between the rotating body 3 and the first fixed body 5 is changed. It is suppressed. As a result, the fluctuation of the magnetic flux transferred between the first and second fixed bodies 5 and 6 is further suppressed.

The axial end 42 of the extending portion 40 is located on the other axial side of the axial end 43 of the axial bulging portion 13, and the axial distance A2 between the axial end 42 and the axial end 43 is the axis It is larger than the maximum value assumed as the amount of direction deviation.
Thereby, even if the rotating body 3 is displaced in the axial direction, the extending portion 40 and the axially bulging portion 13 can reliably face each other in the radial direction and maintain the same first radial facing area. it can.

  Further, the other axial end 44 of the extending portion 40 faces the one end surface 12 of the rotating body 3 in the axial direction, and the first axial air gap a <b> 1 is reduced by the extending portion 40. That is, the extending portion 40 has a function similar to that of the axial extending portion 36 of the second embodiment.

  As a result, the first axial facing area can be formed by the axial facing of the elongated portion 40 and the rotating body 3. For this reason, even if the rotating body 3 is displaced in the radial direction, the first axial facing area is less likely to fluctuate, and as a result, the rotating body 3 is passed between the rotating body 3 and the first fixed body 5 in the axial direction. Fluctuation of magnetic flux is suppressed. As a result, the fluctuation of the magnetic flux transferred between the first and second fixed bodies 5 and 6 is further suppressed.

Further, the inner peripheral surface 45 of the extending portion 40 is on the outer peripheral side with respect to the inner peripheral end 46 of the rotating body 3, and the radial distance B2 between the inner peripheral surface 45 and the inner peripheral end 46 is assumed as a radial deviation amount. Is greater than the maximum value
Thereby, even if the rotating body 3 is displaced in the radial direction, the extending portion 40 and the rotating body 3 can reliably face each other in the axial direction and maintain the same first axial facing area.

[Modification]
According to the rotation angle detection device 1 of the second embodiment, the functions of the radial extension portion 32 and the axial extension portion 36 are both provided in the rotating body 3, and according to the rotation angle detection device 1 of the third embodiment, the diameter Both the functions of the direction extension part 32 and the axial direction extension part 36 are provided in the first fixed body 5. For example, the function of the radial direction extension part 32 is provided in one of the rotating body 3 and the first fixed body 5. And the other side may be provided with the function of the axial extension part 36, and both the rotary body 3 and the first fixed body 5 may be provided with the function of the radial extension part 32. Both of the first fixed bodies 5 may be provided with the function of the axially extending portion 36.

Further, according to the rotation angle detection device 1 of the third embodiment, one extending portion 40 functions as the radial extending portion 32 and the axial extending portion 36, but the radial extending portion 32 and the axial extending portion. 36 may be provided individually.
Moreover, you may comprise the rotation angle detection apparatus 1 without setting any one of the radial direction expansion | extension part 32 and the axial direction expansion | extension part 36. FIG.

  Further, according to the rotation angle detection device 1 of the first to third embodiments, the axial bulging portion 13 bulges from the one end surface 12 of the rotating body 3 in an arc shape along the outer peripheral edge to one axial direction side. However, the present invention is not limited to such a form. For example, the axial bulging portion 13 may be provided so as to bulge in a columnar shape on one side in the axial direction.

  Further, according to the rotation angle detection device 1 of the second and third embodiments, the radial extending portion 32 is provided in an arc shape or an annular shape, and the axial extending portion 36 is provided in a fan shape or an annular shape. For example, the radially extending portion 32 may be provided in a column shape, and the axial extending portion 36 may be provided in a column shape.

  Further, according to the rotation angle detection device 1 of the first to third embodiments, the magnetic flux detection means 4 is fixed to one end in the axial direction of the first fixed body 5, and the magnets 7 and 8 are the extension portions 27 and 28 and the magnetic body 29. However, the positions and shapes of the magnetic flux detection means 4 and the magnets 7 and 8 are not limited to such a mode. For example, a part of the first and second fixed bodies 5 and 6 may be provided by the magnets 7 and 8, and the magnetic flux detection means 4 is provided in the magnetic bodies 25 and 26 or in the first and second fixed bodies 5 and 6. It may be arranged.

  Further, the rotation angle detection device 1 of the first to third embodiments has been used for detecting the rotation angle of the throttle valve, but can also be used for detection of the rotation angle of a valve body used in other intake systems such as an EGR valve. Of course, it may be used for detecting the rotation angle of a valve body other than the valve body used in the intake system.

(A) is a front block diagram which shows a rotation angle detection apparatus, (b) is AA sectional drawing of (a), (c) is the principal part enlarged view of a rotation angle detection apparatus (Example) 1). It is explanatory drawing which shows the fluctuation | variation of the arrangement | positioning relationship by the position shift to the radial direction of a rotary body (Example 1). (Example 2) which is a principal part enlarged view of a rotation angle detection apparatus. (Example 3) which is a principal part enlarged view of a rotation angle detection apparatus. (A) is a top view of a rotation angle detection apparatus, (b) is BB sectional drawing of (a) (conventional example). (A) is a top view of a rotation angle detection apparatus, (b) is a front view of a rotation angle detection apparatus (conventional example).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotation angle detection apparatus 2 Rotating shaft 3 Rotating body 4 Magnetic flux detection means 5 First fixed body 6 Second fixed body 13 Axial bulging portion 14 The other end surface (the other axial end of the first fixed body)
16 outer peripheral surface (the outer peripheral edge of the first fixed body)
32 Radial extension 34 The other axial end (the other axial end of the radial extension)
36 Axial extension part 38 outer peripheral surface (outer peripheral end of the axial extension part)
40 Extension part (radial extension part, axial extension part)
42 One axial end (one axial end of the radially extending portion)
43 One axial end (one axial end of the axial bulge)
45 Inner peripheral surface (inner peripheral end of axial extension)
46 Inner edge (inner edge of rotating body)
a1 first axial air gap a2 second axial air gap b radial air gap A1 axial distance (axial distance between the other axial end of the radially extending portion and the other axial end of the first fixed body )
A2 Axial distance (Axial distance between one axial end of the radially extending portion and one axial end of the axially bulging portion)
B1 radial distance (radial distance between the outer peripheral end of the axially extending portion and the outer peripheral end of the first fixed body)
B2 Radial distance (radial distance between the inner peripheral end of the axially extending portion and the inner peripheral end of the rotating body)

Claims (9)

A rotating body that rotates integrally with a predetermined rotating shaft and passes magnetic flux;
A first fixed body that is arranged coaxially with the rotary shaft and fixed to one side in the axial direction of the rotary body, forms a first axial air gap with the rotary body, and passes a magnetic flux;
A second fixed body fixed on the other axial side of the rotating body, forming a second axial air gap with the rotating body and passing a magnetic flux;
Magnetic flux detection means for detecting magnetic flux passed between the first fixed body and the second fixed body via the rotating body,
The rotating body is
An axially bulging portion that bulges on one side in the axial direction on the outer peripheral side of the first fixed body and faces the first fixed body in the radial direction;
A rotation angle detection device characterized in that a radial air gap is formed between the axial bulging portion and the first fixed body. The rotation angle detection device according to claim 1,
The axial bulging portion has a radially extending portion that extends radially inward toward the first fixed body and faces the first fixed body in a radial direction,
The rotation angle detection device according to claim 1, wherein the radial air gap is reduced by the radial extension portion. In the rotation angle detection device according to claim 2,
The other axial end of the radially extending portion is on one axial side than the other axial end of the first fixed body,
An axial distance between the other axial end of the radially extending portion and the other axial end of the first fixed body is larger than a maximum value assumed as an amount of positional deviation in the axial direction of the rotating body. A rotation angle detection device. The rotation angle detection device according to claim 1,
The first fixed body has a radially extending portion that extends radially toward the axial bulging portion and faces the axial bulging portion in a radial direction,
The rotation angle detection device according to claim 1, wherein the radial air gap is reduced by the radial extension portion. In the rotation angle detection device according to claim 4,
One axial end of the radially extending portion is on the other axial side than one axial end of the axial bulge portion,
An axial distance between one axial end of the radially extending portion and one axial end of the axial bulging portion is larger than a maximum value assumed as a positional deviation amount of the rotating body in the axial direction. The rotation angle detection device. In the rotation angle detection device according to any one of claims 1 to 5,
The rotating body has an axially extending portion that extends in one axial direction toward the first fixed body and faces the first fixed body in the axial direction,
The rotation angle detecting device according to claim 1, wherein the first axial air gap is reduced by the axial extending portion. The rotation angle detection device according to claim 6,
The outer peripheral end of the axially extending portion is closer to the inner peripheral side than the outer peripheral end of the first fixed body,
A rotation characterized in that a radial distance between an outer peripheral end of the axially extending portion and an outer peripheral end of the first fixed body is larger than a maximum value assumed as a displacement amount of the rotating body in the radial direction. Angle detection device. In the rotation angle detection device according to any one of claims 1 to 5,
The first fixed body has an axially extending portion that extends to the other side in the axial direction toward the rotating body and faces the rotating body in the axial direction;
The rotation angle detecting device according to claim 1, wherein the first axial air gap is reduced by the axial extending portion. In the rotation angle detection device according to claim 8,
The inner peripheral end of the axially extending portion is on the outer peripheral side than the inner peripheral end of the rotating body,
A rotation characterized in that a radial distance between an inner peripheral end of the axially extending portion and an inner peripheral end of the rotating body is larger than a maximum value assumed as a displacement amount of the rotating body in the radial direction. Angle detection device.

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