JP2009019926A - Magnetic angle sensor - Google Patents

Abstract

Provided is a magnetic angle sensor capable of maintaining angle detection accuracy by preventing magnetic dust from entering a magnetic gap.
A magnetic gap G3 formed between a magnet 5 and a sensor IC is blocked by a lip seal 6 formed between a cover 8 and a magnet holder 4. The lip seal 6 is fixed to the outer peripheral surface of the magnet holder 4, and when the rotary shaft 1 rotates, the lip seal 6 is slid at the boundary between the first inner peripheral surface 8a of the cover 8 and the second inner peripheral surface 8b of the cover 8. It slides on the moving surface 8c.
[Selection] Figure 1

Description

  The present invention relates to a non-contact magnetic angle sensor that detects rotational displacement in a non-contact manner.

6 and 7 show a non-contact type magnetic angle sensor for detecting the opening degree of the throttle valve (throttle valve) 2 of the engine (see, for example, Patent Document 1). A shaft 103 fixed to the throttle valve 102 by a fastener 123 is rotatably supported by the throttle body 101 via a ball bearing 111 and a dry bearing 113.
At one end of the shaft 103, an annular non-fixed portion 125 fixed to the shaft 103 by means of caulking or the like, a split permanent magnet 141 (hereinafter referred to as a magnet 141) and a split type on the inner peripheral surface. A cylindrical holding portion 126 for holding the yoke 142 (hereinafter referred to as the yoke 142) is provided.

A Hall element (non-contact type detection element) 143 is disposed in the cylindrical holding portion 126 so as to face the magnet 141 and the yoke 142. The hall element 143 is covered with a stator 144 made of an iron-based metal for concentrating the magnetic flux on the hall element 143. The hall element 143 is provided on the sensor cover 120 attached to the throttle body 101 on the extension line of the axis of the rotation axis of the shaft 103.
Here, in the magnetic angle sensor described in Patent Document 1, a space G1 in which a magnetic circuit is formed by the split permanent magnet 141 and the split yoke 142, and between the throttle body 101 and the sensor cover 120 are provided. And a space G2 formed in the middle.
Japanese Patent No. 3893907

In the magnetic angle sensor described in Patent Document 1, magnetic dust such as iron powder generated in the space G2 due to sliding, friction, and corrosion of bearings, gears, and springs is attracted to the magnet in the space G1. May get in. And if magnetic dust adheres to a magnet, a magnetic circuit will be disturb | confused and there exists a problem that the detection accuracy of an angle will fall.
An object of the present invention is to prevent a decrease in angle detection accuracy that may be caused by magnetic dust attracted to a magnet.

  In a magnetic angle sensor that includes an insertion unit and a receiver unit and detects an angle formed by the first detection target object and the second detection target object, the insertion unit can be interlocked with the first detection target object. A rotating shaft connected to the rotating shaft; and a magnet attached to one end of the rotating shaft. The receiver unit is in a state where the insertion unit is inserted into the receiver unit, the detection unit facing the magnet via the magnetic gap, and the detection unit are housed and connected to the second detection target object so as to be interlocked with each other. And a cover that covers a predetermined region including the magnet of the insertion portion in a state where the insertion portion is inserted into the receiver portion. The magnetic angle sensor further includes a lip seal that is formed between a predetermined region including the magnet of the insertion portion and the cover in a state in which the insertion portion is inserted into the receiver portion, and blocks the magnetic gap from the outside. Also equipped.

  The lip seal blocks the magnetic gap and the external space, so that dust does not enter the magnetic gap. Thereby, disturbance of a magnetic circuit can be prevented and the angle detection accuracy can be maintained.

[First embodiment]
The magnetic angle sensor 50 according to the first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view of the magnetic angle sensor 50. In FIG. 1, the x axis is taken in the direction in which the retaining pin 3 is inserted and removed, the z axis is taken in the central axis direction of the rotary shaft 1, and the y axis is taken in the direction perpendicular to the x axis and z axis. FIG. 2 is an exploded perspective view of the magnetic angle sensor 50. FIG. 3 is a cross-sectional view of the magnetic angle sensor 50 in the yz plane shown in FIG. 1 to 3, the same portions are denoted by the same reference numerals, and redundant description is omitted. Similarly, in the other drawings, the same portions are denoted by the same reference numerals, and redundant description is omitted.

The magnetic angle sensor 50 includes an insertion portion 60 that is connected to the first detection target so as to be interlocked with, and a receiver portion 70 that is connected to be capable of interlocking with the second detection target. By detecting the rotation angle formed between the first detection object and the second detection object, the rotation angle formed between the first detection object and the second detection object is detected.
In this example, the insertion portion 60 prevents the rotation shaft 1, the bearing 2 that rotatably supports the rotation shaft 1, the magnet holder 4 formed at one end of the rotation shaft 1, and the rotation shaft 1 and the magnet holder 4. It comprises a retaining pin 3 and a magnet 5 arranged on the tip surface of the magnet holder 4.

The receiver unit 70 accommodates the sensor IC 15 facing the magnet 5 through the magnetic gap G3, the sensor substrate 10 on which the sensor IC 15 is formed, and the sensor IC 15 with the insertion unit 60 inserted into the receiver unit 70. The case 7 includes a cover 8 that covers a predetermined region including at least the magnet 5 of the insertion portion 60, a lid 11 for a housing chamber that houses the sensor IC, and a sleeve 9 for fixing the case 7.
First, the configuration of the insertion unit 60 will be described.
The rotating shaft 1 is connected to one end (not shown) of the rotating shaft 1 so as to be interlocked with the first detection object. For example, the first detection object is fixed to the rotation shaft 1 so that the rotation axis of the first detection object matches the rotation axis of the rotation shaft 1. Further, even when the rotation axis of the first detection object and the rotation axis of the rotation shaft 1 do not coincide with each other, the rotation shaft 1 and the first detection object can be linked via a gear or the like. Thus, the rotation shaft 1 may be rotated according to the rotation of the first detection object.

A ring-shaped groove 1 a is formed on the outer peripheral surface of the other end of the rotating shaft 1 along the outer periphery, and a plate-like protrusion 1 b is formed on the tip surface of the other end of the rotating shaft 1. The rotating shaft 1 is rotatably supported by the housing 17 via the bearing 2. A magnet holder 4 is provided at the other end of the rotating shaft 1.
In the above-described example, the magnet 5 is attached to the rotating shaft 1 via the magnet holder 4, but the magnet 5 may be directly attached to one end of the rotating shaft 1 by adhesive fixing or the like.
The magnet holder 4 has a substantially cylindrical cup shape with one end open and the other end closed, and is formed of a nonmagnetic material such as resin. In this example, the open end 4a of the magnet holder 4 is thick, and two through holes 4b through which the retaining pins 3 are passed are formed substantially in parallel. When the magnet holder 4 and the rotating shaft 1 are fitted together, the through-hole 4b of the magnet holder 4 and the groove 1a of the rotating shaft 1 form one hole through which the retaining pin 3 passes. The closing plate portion of the magnet holder 4 is provided with a recess 4c, and a disc-shaped magnet 5 is bonded and fixed to the recess 4c.

The magnet holder 4 has two outer peripheral surfaces with different diameters. The outer peripheral surface with the larger diameter is the first outer peripheral surface 4d, and the outer peripheral surface with the smaller diameter is the second outer peripheral surface 4e. In this example, the first outer peripheral surface 4d is formed on the open end side. An annular step 4f is formed between the first outer peripheral surface 4d and the second outer peripheral surface 4e.
The retaining pin 3 has a U-shape, and has a U-shaped central portion 3a and a pair of leg portions 3b extending in the same direction from both ends of the central portion 3a. The rotating shaft 1 and the magnet holder 4 are prevented from coming off by fitting the magnet holder 4 and the rotating shaft 1 and inserting the leg 3b of the retaining pin 3 into the through hole 4b. The distal ends of the leg portions 3b are slightly bent inward from each other so that the retaining pins 3 cannot be easily removed from the through holes 4b.

The lip seal 6 is formed of a cylindrical base portion 6a and a flange 6b extending from one end face of the base portion 6a in the outer peripheral direction. In this example, the flange 6b expands in the opposite direction to the base 6a. The thickness of the flange 6b becomes thinner toward the outer peripheral direction. The lip seal 6 is made of, for example, a fluororesin or a slidable rubber.
The lip seal 6 is formed on the outer peripheral surface of the magnet holder 4. For example, an annular end surface 6c on the base 6a side of the lip seal 6 is in contact with an annular step 4f formed at the boundary between the first outer peripheral surface 4d and the second outer peripheral surface 4e, A lip seal 6 is provided on the outer peripheral surface of the magnet holder 4. In this example, the base portion 6a of the lip seal 6 is attached in a direction positioned on the open end side of the magnet holder 42, in other words, on the rear end side of the insertion portion 60, rather than the flange 6b. The lip seal 6 may be fitted into the magnet holder 4, may be bonded and fixed, or may be bonded and fixed after being fitted.

Next, the configuration of the receiver unit 70 will be described.
The sensor IC 15 is positioned opposite to the magnet 5 with the magnetic gap G3 in a state where the insertion part 60 is inserted into the receiver part 70. The sensor IC 15 is formed on the substantially square sensor substrate 10 and is soldered onto the sensor substrate 10. The sensor IC 15 calculates the change in the direction perpendicular to the axial direction of the rotary shaft 1 of the magnetic field generated from the magnet 5 at the detection site of the sensor IC 15. As the sensor IC 15, for example, MLX90316 manufactured by Melexis is used. Other detection means may be used as the sensor IC. The calculated displacement amount is output through the input / output destination line 12 connected to the sensor IC 15 and the sensor substrate 10.

The case 7 made of a non-magnetic material such as resin has a substantially cylindrical cup shape with one end opened and the other end closed, and houses the sensor IC 15 therein. In this example, the sensor substrate 10 on which the sensor IC is formed constitutes a closing plate portion of the substantially cylindrical cup-shaped case 7. The inside of the case 7 is filled with a filler 16 such as a nonmagnetic resin, so that the sensor IC 15 is dustproof and moistureproof. The open end of the case 7 is covered with a lid 11.
The case 7 has a pair of attachment portions 7a that form an angle of 180 degrees with each other on the outer peripheral surface, and the attachment portion 7a has a screw hole 7b for attachment. For example, a metallic sleeve 9 is inserted into the screw hole 7b. The sleeve 9 can secure the tightening strength when the case 7 is attached. The case 7 is fixed to the second detection target object 18 with the screw 13. As a result, the case 7 is connected so as to be interlocked with the second detection target object 18. Note that the case 7 may be connected to the second detection target object 18 via a gear or the like.

The cover 8 has a substantially cylindrical cup shape with one end open and the other end closed. In this example, the cover 8 is formed integrally with the case 7. When one end provided with the magnet 5 of the insertion portion 60 is inserted from the open end side of the cover 8, a predetermined region including the magnet 5 of the insertion portion 60 is covered with the cover 8. In this example, one end where the magnet 5 of the insertion portion 60 is provided is a predetermined region including the magnet 5 of the insertion portion 60.
The cover 8 has two inner peripheral surfaces with different diameters. The inner peripheral surface with the larger diameter is the first inner peripheral surface 8a, and the inner peripheral surface with the smaller diameter is the second inner peripheral surface 8b. The first inner peripheral surface 8 a is located on the open end side of the cover 8. An annular sliding surface 8c is formed at the boundary between the first inner peripheral surface 8a and the second inner peripheral surface 8b. In this example, the sliding surface 8 c is perpendicular to the axial direction of the rotating shaft 1.

  When the insertion portion 60 is inserted into the receiver portion 70, the inner peripheral surface of the flange 6b of the lip seal 6 hits the sliding surface 8c, and the flange 6b is elastically deformed outward by the drag of the sliding surface 8c. Thereby, the external space and the space between the inner peripheral surface of the cover 8 and the outer peripheral surface of the magnet holder 4 are blocked. Further, the space between the inner peripheral surface of the cover 8 and the outer peripheral surface of the magnet holder 4 which is the only space leading to the magnetic gap G3 is cut off from the external space, so that the magnetic gap G3 is also cut off from the external space. Is done. When the insertion portion 60 rotates with respect to the receiver portion 70 around the axis of the rotary shaft 1, the lip seal 6 and the cover 8 slide on the sliding surface 8c.

Thus, the lip seal 6 is formed between the inner peripheral surface of the cover 8 and the outer peripheral surface of the magnet holder 4, and the magnetic gap G3 is shielded from the outside, so that the magnetic gap of magnetic dust and non-magnetic dust is removed. Entering G3 can be prevented. For this reason, angle detection accuracy can be maintained.
In this example, the sliding surface 8 c is formed perpendicular to the axial direction of the rotating shaft 1. For this reason, even when the insertion portion 60 moves in a direction perpendicular to the axial direction of the rotary shaft 1, the amount of movement is a difference of 2 between the outer diameter of the flange 6 b and the diameter of the first inner peripheral surface 8 a. If the value is equal to or less than the value divided by, the magnetic gap G3 can be kept shut from the outside. In this regard, it can be said that the magnetic angle sensor 50 is a magnetic angle sensor that is resistant to displacement in the vertical direction (radial direction) with respect to the axial direction of the rotary shaft 1.

[Second Example]
A magnetic angle sensor 51 according to a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a longitudinal sectional view of the magnetic angle sensor 51. The direction of the cut surface of FIG. 4 is the same as the direction of the yz plane of FIG. 1, which is the direction of the cut surface of FIG.
In the magnetic angle sensor 51 of the second embodiment, the shape of the magnet holder 41 and the cover 81 is different from the shapes of the magnet holder 4 and the cover 8 of the first embodiment, and the lip seal 6 is attached to the magnet holder 41. The mounting direction differs from the magnetic angle sensor 50 of the first embodiment in that the mounting direction is opposite to the mounting direction to the magnet holder 4 of the first embodiment. Other points are the same as those of the magnetic angle sensor 50 of the first embodiment. The duplicate description is omitted for the same parts.

  Unlike the magnet holder 4, the magnet holder 41 has a first outer peripheral surface 4 d that is an outer peripheral surface having a larger diameter formed on the closing plate side of the magnet holder 41, and a second outer surface that is the outer peripheral surface having a smaller diameter. An outer peripheral surface 4 e is formed on the open end side of the magnet holder 42. If the annular stepped portion at the boundary between the first outer peripheral surface 4d and the second outer peripheral surface 4e is a stepped portion 4f, the stepped portion 4f is in contact with the end surface 6c of the lip seal 6 on the base 6a side. The lip seal 6 is attached to the outer peripheral surface of the magnet holder 4. Thereby, the lip seal 6 is attached to the magnet holder 41 in a direction in which the base portion 6a of the lip seal 6 is positioned closer to the closing plate side of the magnet holder 41 than the flange 6b, in other words, the distal end side of the insertion portion 60. The magnet holder 41 and the magnet holder 4 are the same in other respects.

In this example, the cover 81 is different from the cover 8 in that it has one inner peripheral surface 8d having the same diameter. The cover 81 and the cover 8 are the same in other respects.
In a state where the insertion portion 60 is inserted into the receiver portion 70, the outer peripheral surface of the flange 6 b of the lip seal 6 hits the inner peripheral surface 8 d of the cover 81, and the flange 6 b It is elastically deformed. As a result, the magnetic gap G3 is blocked from the external space.
Thus, by blocking the magnetic gap G3 from the outside, it is possible to prevent magnetic dust and non-magnetic dust from entering the magnetic gap G3. For this reason, angle detection accuracy can be maintained.

  In this example, the inner peripheral surface 8 d of the cover 81 that is a sliding surface is a cylindrical surface centered on the axis of the rotating shaft 1. In other words, the inner peripheral surface 8 d is a surface parallel to the axial direction of the rotation shaft 1. For this reason, even if the insertion portion 60 moves in the axial direction of the rotary shaft 1, the magnetic gap G <b> 3 is blocked from the outside as long as the tip of the flange 6 b of the lip seal 6 does not protrude outward from the open end of the cover 81. Can continue. In this regard, it can be said that the magnetic angle sensor 51 is a magnetic angle sensor that is resistant to axial displacement of the rotating shaft 1.

[Third embodiment]
A magnetic angle sensor 52 according to a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a longitudinal sectional view of the magnetic angle sensor 52. The direction of the cut surface in FIG. 5 is the same as the direction of the yz plane in FIG. 1, which is the direction of the cut surface in FIG.

The magnetic angle sensor 52 of the third embodiment is different from the magnetic angle sensors 50 and 51 in that two lip seals 61 and 62 are provided. Other points are the same as those of the magnetic angle sensors 50 and 51. The duplicate description is omitted for the same parts.
The lip seal 61 is a lip seal that slides on a surface (sliding surface 8c) perpendicular to the axial direction of the rotary shaft 1 described in the first embodiment, and the lip seal 62 is a lip seal 62 in the second embodiment. The lip seal slides on the cylindrical surface (inner peripheral surface 8a) centered on the axis of the rotating shaft 1 as described.

  Thus, by providing two lip seals, the ability to block the magnetic gap G3 from the outside can be enhanced as compared with the case of providing only one lip seal. In this example, the magnetic angle sensor 52 includes a lip seal 61 that is resistant to displacement in a direction perpendicular to the axial direction of the rotating shaft 1 and a lip seal 62 that is resistant to displacement in the axial direction of the rotating shaft 1. . For this reason, the magnetic angle sensor 52 is resistant to both a shift in a direction perpendicular to the axial direction of the rotary shaft 1 and a shift in the axial direction of the rotary shaft 1.

[Modifications, etc.]
In the above embodiment, the lip seals 6, 61, 62 are fixed to the magnet holders 4, 41, 42 of the insertion portion 60, but the lip seals 6, 61, 62 may be fixed to the rotary shaft 1.

Further, the lip seals 6, 61, 62 may be fixed to the covers 8, 81, 82. In this case, the lip seal 6 slides on the outer surface of the magnet holders 4, 41, 42 and the outer surface of the rotating shaft 1, for example.
In the third embodiment, two lip seals are provided, but three or more lip seals may be provided.
The lip seals 6, 61, 62 need not completely seal the magnetic gap G3. There may be gaps smaller than the magnetic dust that may be generated.

In this example, the sensor IC 15 is provided as the angle detection means, but any angle detection means can be provided.
A part of the inner peripheral surface of the open end 4a may be removed at the center of the through hole 4b. In this case, when the magnet holder 4 and the rotary shaft 1 are fitted together, the through-hole 4b of the magnet holder 4, the part of the inner peripheral surface of the open end 4a, and the groove 1a of the rotary shaft 1 are inserted. Forms one hole for the retaining pin 3 to pass through.
Needless to say, other modifications are possible without departing from the spirit of the present invention.

The perspective view of the magnetic type angle sensor 50 by a 1st Example. The disassembled perspective view of the magnetic type angle sensor 50 by a 1st Example. The longitudinal cross-sectional view by the yz plane in FIG. 1 of the magnetic type angle sensor 50 by a 1st Example. The longitudinal cross-sectional view of the magnetic type angle sensor 51 by a 2nd Example. The longitudinal cross-sectional view of the magnetic type angle sensor 52 by a 3rd Example. The figure which shows the non-contact-type magnetic angle sensor which detects the opening degree of the throttle valve 102 of the engine by background art (the 1). The figure which shows the non-contact-type magnetic angle sensor which detects the opening degree of the throttle valve 102 of the engine by background art (the 2).

Explanation of symbols

1: rotating shaft, 1a: groove, 1b: protrusion, 2: bearing, 3: retaining pin, 3a: center, 3b: leg, 4: magnet holder, 4a: open end, 4b: through hole, 4c : Recess, 4d: outer peripheral surface, 4e: outer peripheral surface, 4f: stepped portion, 5: magnet, 6: lip seal, 6a: base, 6b: flange, 7: case, 7a: mounting portion, 7b: hole, 8: Cover, 8a: inner peripheral surface, 8b: inner peripheral surface, 8c: sliding surface, 8d: inner peripheral surface, 9: sleeve, 10: sensor substrate, 11: ball bearing, 11: lid, 12: input / output destination line , 13: Dry bearing, 15: Sensor IC, 16: Filler, 17: Housing, 18: Object to be detected, 41: Magnet holder, 42: Magnet holder, 50: Magnetic angle sensor, 51: Magnetic angle sensor , 52: Magnetic angle sensor, 60: Insertion part, 61: Lip seal, 2: lip seal, 70: receiving part, 81: cover, 101: throttle body, 102: throttle valve, 103: shaft, 120: sensor cover, 123: fastener, 125: non-fixed part, 126: holding part, 141: Permanent magnet (magnet), 142: Yoke, 143: Hall element, 144: Stator, G1: Space, G2: Space, G3: Magnetic gap

Claims (6)

In a magnetic angle sensor that includes an insertion part and a receiver part and detects an angle formed between the first detection target object and the second detection target object,
The insertion part is
A rotation axis connected to the first object to be detected,
A magnet attached to one end of the rotating shaft;
With
The receiver is
In a state where the insertion portion is inserted into the receiver portion, detection means facing the magnet via a magnetic gap,
A case that houses the detection means and is connected to the second detection target object;
In a state where the insertion portion is inserted into the receiver portion, a cover that covers a predetermined region including the magnet of the insertion portion;
With
Further, in a state where the insertion portion is inserted into the receiver portion, a lip seal is formed between a predetermined region including the magnet of the insertion portion and the cover, and blocks the magnetic gap from the outside.
Magnetic angle sensor equipped with. The magnetic angle sensor according to claim 1,
The magnetic angle sensor, wherein the insertion portion and the receiver portion are separable. The magnetic angle sensor according to claim 1 or 2,
The lip seal slides in a plane perpendicular to the axial direction of the rotation shaft when the insertion portion rotates with respect to the receiver portion.
A magnetic angle sensor. The magnetic angle sensor according to claim 1 or 2,
The lip seal slides on a cylindrical surface centered on the axis of the rotation shaft when the insertion portion rotates with respect to the receiver portion.
A magnetic angle sensor. The magnetic angle sensor according to any one of claims 1 to 4,
The lip seal comprises at least a first lip seal and a second lip seal,
The first lip seal slides in a plane perpendicular to the axial direction of the rotation shaft when the insertion portion rotates with respect to the receiver portion,
The second lip seal slides on a cylindrical surface centered on the axis of the rotation shaft when the insertion portion rotates with respect to the receiver portion.
A magnetic angle sensor. The magnetic angle sensor according to any one of claims 1 to 5,
The magnet is attached to one end of the rotating shaft via a magnet holder,
The lip seal is fixed to the outer peripheral surface of the magnet holder,
A magnetic angle sensor.

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