JP7042634B2 - Rotation angle detector - Google Patents

Description

The present invention relates to a rotation angle detecting device that detects the rotation angle of a rotating body rotatably supported.

Conventionally, as a rotation angle detection device for detecting the rotation angle of such a rotating body, a throttle body that rotatably supports the rotation axis of the throttle valve and a magnetic sensor attached to the throttle body to detect the rotation angle of the rotation axis. The one with and is known. In this device, the rotation angle of the rotation axis is detected by detecting the magnetic field generated by the magnet attached to the rotation axis with a magnetic sensor (see, for example, Patent Document 1).

In the rotation angle detection device of Patent Document 1, the magnet is molded into a cylindrical shape having a height larger than the thickness of the outer peripheral portion of a plate member having a predetermined thickness fixed to one end of the rotation shaft. It is integrated. N poles and S poles are formed on the magnet at a predetermined pitch in the circumferential direction. The magnetic sensor detects a change in the direction of the magnetic field lines from such a multipolar magnet by a Hall element, and is arranged so as to face the end face of the magnet.

When the rotation axis rotates, the direction of the magnetic field lines detected by the magnetic sensor changes. Therefore, the magnetic sensor outputs a detection signal according to the change in the direction of the magnetic force lines according to the rotation angle. This detection signal is fed back to the drive control device of the rotating shaft as representing the rotation angle of the rotating shaft, and the opening / closing control of the throttle valve is performed.

Japanese Unexamined Patent Publication No. 2015-1479

However, according to the rotation angle detecting device of Patent Document 1, since the rotation angle is detected based on the change in the direction of the magnetic field lines from the multipolar magnet, the influence of the magnetic field lines from the outside other than the magnetic field lines by the multipolar magnet is exerted. It is necessary to arrange more magnetic field lines from the multi-pole magnet in the space where the magnetic sensor is arranged so that the magnetometer does not appear. For this reason, the multi-pole magnet is formed large and is made of an expensive material that generates many lines of magnetic force, which hinders the low cost and miniaturization of the rotation angle detecting device.

An object of the present invention is to provide a smaller rotation angle detection device with high detection accuracy by using a magnetic detection element that detects the direction of a magnetic field line in view of the problem of the prior art.

The rotation angle posting device according to the first invention is
With a rotating body,
A body that rotatably supports the rotating body and
A rotation angle sensor attached to the body and detecting the rotation angle of the rotating body by a magnetic detection element,
In a rotation angle detecting device provided with a body to be detected that is attached to the rotating body and generates a magnetic field detected by the magnetic detection element.
The detected body is fixed to one end of the rotating body in the direction of the rotation axis, and at least a pair of detection side N pole surfaces and detection side S pole surfaces are arranged on the one side. It is a magnet
The rotation angle sensor is arranged on one side of the object to be detected, and detects the direction of a magnetic field line connecting the detection side N pole surface and the detection side S pole surface.
The detected body is provided with a volume reducing portion having a depth in the direction of the rotation axis on the boundary line between the detection side N pole surface and the detection side S pole surface.
When viewed in the direction of the rotation axis, the volume reduction portion is formed from the outer peripheral surface of the object to be detected toward the inside in the radial direction about the rotation axis.
The volume reducing portion is characterized in that it accommodates at least a part of a fixing structure for fixing the detected body to the rotating body and receives a fixing force for fixing the detected body to the rotating body.

According to the first invention, since the object to be detected is composed of an integrally molded magnet, the object to be detected can be easily attached to the rotating body. Further, since the volume reduction portion is provided on the boundary line between the detection side N pole surface and the detection side S pole surface of the detected body, it is possible to reduce the number of magnetic field lines passing through the magnetic circuit passing through the volume reduction portion. By that amount, the magnetic flux density in the space where the magnetic detection element is arranged can be increased by increasing the magnetic field lines from the detection side N pole surface to the detection side S pole surface through the space where the magnetic detection element exists. ..

Further, since the volume reducing portion accommodates a part of the fixed structure, it is possible to prevent the fixed structure from protruding from the detected body in the direction of the rotation angle sensor. This makes it possible to bring the rotation angle sensor closer to the object to be detected without hindrance, so that the magnetic detection element can be brought closer to a space with a high magnetic flux density near the object to be detected, and the detection accuracy of the rotation angle sensor is improved. Can be made to. Therefore, it is possible to provide a rotation angle detection device that is smaller and has higher detection accuracy.

The rotation angle detecting device according to the second invention is the same as that in the first invention.
The rotating body has a yoke extending in a direction orthogonal to the rotation axis at one end thereof and strengthening a magnetic circuit together with the detected body.
The detected body has a base-side S pole corresponding to the detection-side N-pole constituting the detection-side N-pole surface and a base-side N-pole corresponding to the detection-side S-pole constituting the detection-side S-pole surface. It is characterized in that it is attached to the yoke in a state of being in contact with the one side surface of the above.

According to the second invention, the magnetic circuit including the object to be detected is strengthened by the yoke, and the magnetic field lines from the N pole surface on the detection side to the S pole surface on the detection side can be increased, so that the detection accuracy by the rotation angle sensor is improved. be able to.

The rotation angle detecting device according to the third invention is the same as that in the first or second invention.
The volume reduction portion includes a wall surface extending in the direction of the rotation axis from the end surface on one side of the detected body.
The wall surface extends from one end surface to a region up to one half of the thickness of the object to be detected in the rotation axis direction or a region exceeding the half, and the wall surface of the object to be detected extends. It is characterized in that it is in contact with a material or space having a magnetic permeability lower than that of the magnetic permeability.

According to the third invention, the region opposite to the above region in the rotation axis direction of the detected body functions as a yoke, and the magnetic field lines from the wall surface on the N pole side to the wall surface on the S pole side in the volume reduction portion are transparent. It is reduced by a material or space with a low magnetic permeability. Therefore, the magnetic flux lines from the N pole surface on the detection side to the S pole surface on the detection side form a dense magnetic flux in the space where the magnetic detection element detects the magnetic field. This makes it possible to improve the detection accuracy of the magnetic field lines by the magnetic detection element and improve the detection accuracy of the rotation angle sensor.
In the first invention, the rotation angle detecting device according to the fourth invention has a groove shape in which the volume reducing portion extends from the outer peripheral surface of the detected body to a cylindrical space provided in the center of the detected body. The detected body is fixed to the rotating body by insert-molding a range extending from the outer periphery of the detected body to the rotating body with a resin.

It is a perspective view which shows the main part of the intake air control device to which the rotation angle detection device which concerns on one Embodiment of this invention is applied. 2A is a perspective view showing a rotating body to which a magnet is attached in the apparatus of FIG. 1, and FIG. 2B is a perspective view showing a portion of FIG. 2A excluding a mold resin portion. 3A is a perspective view showing the magnet of the device of FIG. 1, FIG. 3B is a cross-sectional view showing the state of the magnetic field lines generated by the magnet, and FIG. 3C is a cross-sectional view showing the magnetic field lines in the vicinity of the volume reduction portion of the magnet. It is sectional drawing which shows the state. 4A is a perspective view showing a modified example of the detected body attached to the rotating body, FIG. 4B is a cross-sectional view showing a state in which the detected body is attached to the rotating body, and FIG. 4C is a cross-sectional view. It is a perspective view which shows another modification of the detected body attached to a rotating body, and FIG. 4D is a cross-sectional view which shows the state which the detected body is attached to the rotating body.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a main part of an intake air control device to which a rotation angle detection device according to an embodiment of the present invention is applied. As shown in FIG. 1, the intake control device 1 is mounted on an internal combustion engine, has a body 3 provided with an intake pipe 2 leading to a combustion chamber of the internal combustion engine, and a valve shaft rotatably supported by the body 3. 4 and a valve body 5 fixed to the valve shaft 4 are provided.

The valve body 5 is arranged inside the intake pipe 2 and is driven to adjust the flow rate of air flowing into the combustion chamber of the internal combustion engine. The intake pipe 2 is connected to a pipe line leading to a combustion chamber of an internal combustion engine via a connecting surface 3a.

Further, the intake control device 1 includes an electric motor 7 that generates power for driving the valve body 5, a power transmission mechanism 8 that transmits the power generated by the electric motor 7 to the valve body 5, an electric motor 7, and an electric motor 7. A power chamber 9 for accommodating the power transmission mechanism 8 is provided. The power chamber 9 is closed by a lid portion 6 fixed to the body 3 by a screw 10.

The power transmission mechanism 8 includes a pinion gear 8a fixed to the rotating shaft of the electric motor 7 and a lever gear 8b fixed to the end of the valve shaft 4 and meshing with the pinion gear 8a, and rotates the rotating shaft of the electric motor 7. The force is decelerated and transmitted to the valve shaft 4.

The valve shaft 4, the valve body 5, the lever gear 8b, and the like constitute a rotating body 11 rotatably supported by the body 3 via the valve shaft 4. Inside the lid portion 6, a rotation angle sensor 12 that detects the rotation angle of the rotating body 11 by a magnetic detection element is provided. As the magnetic detection element, for example, a Hall element is used.

FIG. 2A shows the rotating body 11. As shown in FIG. 2A, the lever gear 8b is composed of a mold resin portion 14 formed by insert molding with the insert plate 13 as an insert component.

2B shows the portion of FIG. 2A except for the mold resin portion 14. As shown in FIG. 2B, the insert plate 13 is fixed to the end of the valve shaft 4 on the lid 6 side and extends in a direction orthogonal to the rotation axis of the valve shaft 4. Hereinafter, the direction of the lid portion 6 side, which is one side of the rotation axis of the valve shaft 4, is referred to as the “D direction”.

A magnet 15 as a body to be detected is provided on the D direction side of the insert plate 13. The magnet 15 has a substantially cylindrical outer shape, and is arranged so that its central axis is located on the rotation axis of the valve shaft 4.

As shown in FIG. 3A, the main portion 16 of the magnet 15 has a cylindrical outer shape whose height is smaller than the radius, and is a cylindrical space whose radial center side penetrates in the central axis direction. The surfaces of the main portion 16 facing the rotation angle sensor 12 are a pair of detection-side N-pole surfaces 18a and detection-side S-pole surfaces 19a with the boundary line 17 interposed therebetween.

That is, the main portion 16 has a detection side N pole 18 constituting the detection side N pole surface 18a and a detection side S pole 19 constituting the detection side S pole surface 19a on the D direction side thereof, and a base corresponding to these. It has a side S pole 20 and a base side N pole 21 on the side opposite to the D direction.

Therefore, a magnetic field line (magnetic field) connecting the detection side N pole surface 18a and the detection side S pole surface 19a is generated in the space on the rotation angle sensor 12 side of the main portion 16. The rotation angle sensor 12 described above detects the direction of the magnetic field line on the D direction side of the main portion 16 based on the magnetic field detected by the magnetic detection element.

The magnet 15 is provided with volume reducing portions 22 and 23 having a depth in the rotation axis direction of the valve shaft 4 on the boundary line 17. The volume reducing portions 22 and 23 include a wall surface 24 extending in the direction opposite to the D direction from the end surface on the D direction side of the main portion 16.

The wall surface 24 extends from the end face to a region up to half the thickness of the magnet 15 in the direction of the rotation axis or a region exceeding the half, and has a magnetic permeability lower than the magnetic permeability of the magnet 15. It is in contact with the material or space of.

The magnet 15 includes mounting portions 25 and 26 extending radially outward of the main portion 16 along a boundary line 17 from a portion of the main portion 16 opposite to the wall surface 24 in the D direction. The mounting portions 25 and 26 are provided with screw holes 27 and 28, respectively. The magnet 15 is integrally molded including the mounting portions 25 and 26.

Therefore, as shown in FIG. 2B, the magnet 15 is easily fixed to the insert plate 13 simply by passing the screws 29 and 30 through the screw holes 27 and 28 and screwing them into the insert plate 13. This fixing is performed in a state where the base side S pole 20 and the base side N pole 21 are in contact with the surface of the insert plate 13 on the D direction side.

Further, at the time of this fixing, a part of the heads of the screws 29 and 30 are housed in the volume reducing portions 22 and 23, respectively. As a result, it is avoided that the head portion protrudes toward the D direction side from the D direction side end surface of the magnet 15. Further, the bottom portions of the volume reducing portions 22 and 23 function as seat surfaces for receiving the fixing force of the screws 29 and 30.

The insert plate 13 is made of a magnetic material suitable for the yoke. Therefore, the insert plate 13 functions together with the magnet 15 as a yoke for strengthening the magnetic circuit.

Further, the insert plate 13 has a simple form in which the plate material is simply cut. Therefore, unlike the forged product, the insert plate 13 does not need to be annealed because the high magnetic permeability of the plate material is maintained in the production thereof. Therefore, the insert plate 13 can be easily manufactured.

In this configuration, as shown in FIG. 3A, the magnet 15 has a magnetic field line m1 from the detection side N pole surface 18a to the detection side S pole surface 19a through the space on the D direction side of the main portion 16. Further, a magnetic field line m2 is generated from the detection side N pole 18 to the detection side S pole through the inside and space of the volume reduction portions 22 and 23 of the main portion 16.

However, the magnetic field lines from the wall surface 24 portion on the detection side N pole 18 side of the volume reduction portions 22 and 23 to the wall surface 24 portion on the detection side S pole 19 side through the space of the volume reduction portions 22 and 23 are the magnetic permeability of the space. Is small, so it is less than when the volume reducing portions 22 and 23 are not present. Since there are many magnetic field lines m1 passing through the space on the D direction side of the main portion 16 by that amount, the magnetic flux density in the space on the D direction side of the main portion 16 is increased.

On the other hand, as shown in FIG. 3B, the insert plate 13 functions as a yoke of the magnet 15. Therefore, the magnetic circuit including the magnet 15 is strengthened by the yoke to reduce the leakage flux, the magnetic field line m1 passing through the space on the D direction side of the main portion 16 increases, and the magnetic flux in the space on the D direction side of the main portion 16 increases. The density is increased.

On the other hand, in the cross section that passes through the volume reduction portion 22 of the magnet 15 and is perpendicular to the boundary line 17, the base side S pole 20 and the base side N pole 21 are the detection side N pole 18 and the detection side N pole 18 as shown in FIG. 3C. Functions as a yoke for the side S pole.

That is, the cross-sectional portion of FIG. 3C has a function similar to that of the U-shaped magnet. The increased magnetic field lines m4 reach the detection side S pole surface 19a from the detection side N pole surface 18a through the space on the D direction side of the volume reducing portion 22. The same applies to the cross-sectional portion that passes through the volume reduction portion 23 and is perpendicular to the boundary line 17.

As described above, the magnetic field lines from the detection side N pole surface 18a to the detection side S pole surface 19a through the space on the D direction side of the main portion 16 are increased by the volume reducing portions 22, 23 and the insert plate 13.

In this state, when the valve shaft 4 is rotated by the electric motor 7 and the amount of intake air flowing through the intake pipe 2 is controlled, the rotation angle of the valve shaft 4 detected by the rotation angle sensor 12 is fed back and electric. The drive of the motor 7 is controlled.

At this time, in detecting the rotation angle of the valve shaft 4, the rotation angle sensor 12 uses the detection side N pole surface 18a and the detection side S pole surface 19a generated in the space on the rotation angle sensor 12 side of the main portion 16. The direction of the connecting magnetic field lines is detected. Then, as described above, the lines of magnetic force are increased by the volume reducing portions 22, 23 and the insert plate 13.

Therefore, the rotation angle of the valve shaft 4 is detected with high accuracy by the rotation angle sensor 12. As a result, good intake control by the intake control device 1 is achieved.

As described above, according to the present embodiment, since the object to be detected is composed of the integrally molded magnet 15, the object to be detected can be easily attached to the rotating body 11. Further, since the volume reducing portions 22 and 23 are provided on the boundary line between the detection side N pole surface 18a and the detection side S pole surface 19a of the magnet 15, the magnetic flux lines passing through the space on the magnet 15 side of the volume reducing portions 22 and 23. Can be increased, and the magnetic flux density in the space on the magnet 15 side of the volume reducing portions 22 and 23 can be increased.

Further, since the volume reducing portions 22 and 23 accommodate a part of the screws 29 and 30 as a fixed structure, it is possible to prevent the screws 29 and 30 from protruding from the magnet 15 in the D direction. As a result, the rotation angle sensor 12 can be brought close to the magnet 15 without any trouble, so that the detection accuracy of the rotation angle sensor 12 can be improved. Therefore, it is possible to provide a rotation angle detection device that is smaller and has higher detection accuracy.

Further, the magnetic circuit including the magnet 15 is strengthened by the yoke function of the insert plate 13, and the magnetic field lines from the detection side N pole surface 18a to the detection side S pole surface 19a can be increased, so that the detection accuracy by the rotation angle sensor 12 can be improved. It can be further improved. Further, since the insert plate 13 has a simple plate shape, the insert plate 13 that functions as the yoke of the magnet 15 can be easily formed without the need for annealing.

Further, by providing the volume reducing portions 22 and 23 on the magnet 15, the side opposite to the D direction side of the volume reducing portions 22 and 23 of the magnet 15 functions as a yoke, and the detection side N of the volume reducing portions 22 and 23 is provided. It is possible to reduce the lines of magnetic force from the wall surface 24 portion on the pole 18 side to the wall surface 24 portion on the detection side S pole 19 side. As a result, the detection accuracy of the rotation angle sensor 12 can be further improved by further increasing the lines of magnetic force from the detection side N pole surface 18a to the detection side S pole surface 19a.

4A and 4B are perspective views and cross-sectional views showing a modified example of the detected body attached to the rotating body. The detected body 31 of FIG. 4A is similar to the main portion 16 of the magnet 15 of FIG. 3A in that it is a magnet having a substantially cylindrical shape.

However, the detected body 31 has a cylindrical space on the radial center side in which the depth of the volume reducing portions 32 and 33 is shallower than half the height (thickness) of the detected body 31. It differs from the magnet 15 in that it does not have any equivalent to the mounting portions 25 and 26.

Therefore, the detected body 31 is fixed to the rotating body 34 by the two clips 35 whose both ends engage with the bottom of the volume reducing portions 32 and 33 and the rotating body 34, respectively, as shown in FIG. 4B. It is done without going through such a yoke. If the rotating body 34 is made of a magnetic material, the rotating body 34 functions as a yoke. Other configurations and operations are the same as in the case of the magnet 15 in FIG. 3A.

4C and 4D are perspective views and cross-sectional views showing another modification of the detected body attached to the rotating body. The detected body 36 of FIG. 4C is similar to the main portion 16 of the magnet 15 of FIG. 3A in that it has a substantially cylindrical shape.

However, unlike the magnet 15, the detected body 36 is arranged in the order of the detection side N pole surface 37a, the detection side S pole surface 38a, the detection side N pole surface 39a, and the detection side S pole surface 40a in the circumferential direction. It has two pairs of detection-side N-pole planes and detection-side S-pole planes. Correspondingly, the detected body 36 has a detection side N pole 37, a detection side S pole 38, a detection side N pole 39, a detection side S pole 40, a base side S pole 45, a base side N pole 46, and a base side. It has an S pole 47 and an N pole 48 on the base side.

Four volume reducing portions 41 to 44 are provided on the boundary line of each adjacent portion of the detection side N pole surface 37a, the detection side S pole surface 38a, the detection side N pole surface 39a, and the detection side S pole surface 40a. However, the volume reducing portions 41 to 44 are provided as grooves from the outer peripheral surface of the detected body 36 to the central cylindrical space 53.

As shown in FIG. 4D, the fixing of the detected body 36 to the rotating body 49 uses these as insert parts, and the magnetic permeability extends from the outer periphery of the detected body 36 to the fixed portion of the rotating body 49 to the detected body 36. This is done by insert molding with a low resin 50. Therefore, this fixing is performed without using a yoke such as the insert plate 13.

For this purpose, the rotating body 49 has a horizontal hole 51 penetrating in the lateral direction and a vertical hole 52 penetrating the horizontal hole 51 from the end surface on the side to be detected 36. As shown in FIG. 4D, the resin 50 covers the outer periphery of the fixed portion of the detected body 36 and the rotating body 49 to the detected body 36, and the horizontal hole 51, the vertical hole 52, and the detected body 36 of the rotating body 49. It enters the central space 53 and the volume reducing portions 41 to 44 to connect the detected body 36 and the rotating body 49.

Further, if the rotating body 49 is made of a magnetic material, the rotating body 49 functions as a yoke. Other configurations and operations are the same as in the case of the magnet 15 in FIG. 3A.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto. For example, the rotation angle detecting device of the present invention is not limited to the rotating body 11 of the intake control device 1 of FIG. 2A, but is also used to detect the rotation angle of another rotating body rotatably supported by the body. Can be done.

As the magnetic detection element of the rotation angle sensor 12, a magnetic detection element other than the Hall element is used as long as it can be used to detect the direction of the magnetic field line connecting the detection side N pole surface and the detection side S pole surface. You may.

Further, the volume reducing portion may be provided in a range from the end face on the D direction side to the end face on the opposite side of the detected body, if the fixed structure for fixing the detected body to the rotating body allows.

1 ... Intake control device, 2 ... Intake pipe, 3 ... Body, 3a ... Connection surface, 4 ... Valve shaft, 5 ... Valve body, 6 ... Cover, 7 ... Electric actuator, 8 ... Power transmission mechanism, 8a ... Pinion gear , 8b ... Lever gear, 9 ... Power chamber, 10 ... Screw, 11, 34, 49 ... Rotating body, 12 ... Rotation angle sensor, 13 ... Insert plate, 14 ... Mold resin part, 15 ... Magnet (detected body), 16 ... Main part, 17 ... Boundary line, 18, 37, 39 ... Detection side N pole, 18a, 37a, 39a ... Detection side N pole surface, 19, 38, 40 ... Detection side S pole, 19a, 38a, 40a ... Detection Side S pole surface, 20, 45, 47 ... Base side S pole, 21, 46, 48 ... Base side N pole, 22, 23, 32, 33, 41 to 44 ... Volume reduction part, 24 ... Wall surface, 25, 26 ... Mounting part, 27, 28 ... Screw hole, 29, 30 ... Screw (fixed structure), 31, 36 ... Detected body, 35 ... Clip, 50 ... Resin, 51 ... Horizontal hole, 52 ... Vertical hole, 53 ... Space ..

Claims (4)

With a rotating body,
A body that rotatably supports the rotating body and
A rotation angle sensor attached to the body and detecting the rotation angle of the rotating body by a magnetic detection element,
In a rotation angle detecting device provided with a body to be detected that is attached to the rotating body and generates a magnetic field detected by the magnetic detection element.
The detected body is fixed to one end of the rotating body in the direction of the rotation axis, and at least a pair of detection side N pole surfaces and detection side S pole surfaces are arranged on the one side. It is a magnet
The rotation angle sensor is arranged on one side of the object to be detected, and detects the direction of a magnetic field line connecting the detection side N pole surface and the detection side S pole surface.
The detected body is provided with a volume reducing portion having a depth in the direction of the rotation axis on the boundary line between the detection side N pole surface and the detection side S pole surface.
When viewed in the direction of the rotation axis, the volume reduction portion is formed from the outer peripheral surface of the object to be detected toward the inside in the radial direction about the rotation axis.
The volume reducing portion accommodates at least a part of a fixing structure for fixing the detected body to the rotating body, and receives a fixing force for fixing the detected body to the rotating body. Detection device. The rotating body has a yoke extending in a direction orthogonal to the rotation axis at one end thereof and forming a magnetic circuit together with the detected body.
The detected body has a base-side S pole corresponding to the detection-side N-pole constituting the detection-side N-pole surface and a base-side N-pole corresponding to the detection-side S-pole constituting the detection-side S-pole surface. The rotation angle detecting device according to claim 1, wherein the rotation angle detecting device is attached to the yoke in a state of being in contact with the one side surface of the above. The volume reduction portion includes a wall surface extending in the direction of the rotation axis from the end surface on one side of the detected body.
The wall surface extends from one end surface to a region up to one half of the thickness of the object to be detected in the direction of the rotation axis or a region exceeding the half, and the wall surface of the object to be detected extends. The rotation angle detecting device according to claim 1 or 2, wherein the device is in contact with a material or space having a magnetic permeability lower than that of the magnetic permeability. The volume reduction portion is provided as a groove-like structure extending from the outer peripheral surface of the detected body to a cylindrical space provided in the center of the detected body.
The rotation angle detecting device according to claim 1, wherein the detected body is fixed to the rotating body by insert-molding a range extending from the outer periphery of the detected body to the rotating body with a resin. ..

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