JP4896910B2 - Arc type angle sensor - Google Patents

Description

  The present invention relates to an arc-shaped angle sensor for detecting a rotation angle, and more particularly to an arc-shaped angle sensor with improved angle detection accuracy at both ends of the sensor.

  The arc-shaped angle sensor includes a stator having a plurality of slots around which coils are wound, and a rotor that is formed of an electromagnetic steel plate and rotates in an arc shape.

  Depending on the device on which the arc-shaped angle sensor is mounted, the number of slots may be limited due to space limitations. For example, when the number of detection coils is two of a sin wave and a cosine wave, the number of slots is preferably a multiple of four. When the number of slots is a multiple of 4, the voltage of the detection coil can be balanced by alternately reversing the winding of the exciting coil that generates the magnetic field. For this reason, the output voltage of the detection coil has a waveform with 0 as the axis of symmetry, and is suitable for input to an R / D converter (resolver digital converter), which is a converter that converts the output of the arc-shaped angle sensor into an angle. Become.

  However, when the number of slots cannot be a multiple of 4, for example, the following problem occurs. Consider the case where the number of slots is 10, which is not a multiple of 4. FIG. 2 is a view showing an arc-shaped angle sensor having ten slots. 2A is a side view of the arc-shaped angle sensor, and FIG. 2B is a diagram showing the winding direction of each coil in each slot. The number represents the number of turns.

  Thus, if the detection coil 41 is not wound around the slots at both ends, no output can be obtained at both ends of the arc-shaped angle sensor as shown by the waveforms 53 and 54 in FIG. For this reason, there is a problem that the angle output from the R / D converter cannot be obtained at both ends of the arc-shaped angle sensor, as shown by the dotted line portions at both ends of the line 62 in FIG.

  Therefore, it is conceivable to wind detection coils around the slots at both ends. FIG. 3 is a diagram showing a case where a detection coil is wound around slots at both ends. Since leakage of magnetic flux occurs from the coils in the slots at both ends, the output voltage from the detection coils in the slots at both ends decreases as shown by the waveforms 55 and 56 in FIG. There was a problem.

  Furthermore, the magnetic field generated by the exciting coil is not canceled out, and the output voltage of the detection coil increases, resulting in a waveform separated from zero. For this reason, there has been a problem that the R / D converter may not be able to convert the input signal into an angle.

  In the following, it is referred to as offset when the waveform of the graph is away from 0 on the horizontal axis.

In this regard, a technique has been proposed in which detection accuracy is improved by shifting the center of rotation of the rotor toward the stator and shortening the distance from the rotor at both ends of the stator (for example, Patent Document 1).
JP-A-2005-55183

  However, the technique described in Patent Document 1 has a problem in that a desired accuracy cannot be improved because there is a limit to the distance from the rotor that can be shortened at both ends of the stator.

  In addition, the technique described in Patent Document 1 has a problem in that the offset point cannot be solved.

  The present invention has been made in view of the above problems, and an arc-shaped angle sensor capable of suppressing offset regardless of the number of slots and improving detection accuracy at both ends of the arc-shaped angle sensor, and An object of the present invention is to provide a method for improving the accuracy of an arc-shaped angle sensor.

  In order to achieve this object, the present invention provides a rotor that is formed of an electromagnetic steel plate and rotates in an arc shape, and is curved along an arc in which the rotor rotates, and is provided in a row facing the rotor along the arc. A plurality of slots having a plurality of slots, an exciting coil that is wound so as to be reversely wound in adjacent slots and generating a magnetic field by an electric current, and a sin wave detection that is wound in every other slot from the end A coil, a cos wave detection coil wound around a slot where a sin wave detection coil is not wound, and a slot excluding the slots at both ends are wound in a reverse direction from the excitation coil, and a magnetic field is generated by current. A sub-coil to be generated, and the number of turns of the sin wave detection coil and the cos wave detection coil in the slots at both ends is set to the number of turns of the sin wave detection coil and the co in the slots other than both ends. Providing arcuate angle sensor, characterized in that it has more than the number of turns of the wave detection coil.

  According to the present invention, the offset is suppressed, and the output voltage of the sin wave detection coil and the cos wave detection coil in the slots at both ends is suppressed from being lowered, so that the angle detection accuracy in the slots at both ends is improved. .

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an arc-shaped angle sensor and an embodiment of a method for improving the accuracy of an arc-shaped angle sensor according to the present invention will be described in detail with reference to the drawings. In addition, while attaching | subjecting the same code | symbol about the same location in each figure, the overlapping description is abbreviate | omitted.

  FIG. 1 is a diagram showing an arc-shaped angle sensor and a method for improving the accuracy of the arc-shaped angle sensor of the present embodiment. As shown in FIG. 1 (a), the arc-shaped angle sensor of the present embodiment is formed of an electromagnetic steel plate, and is curved along a rotor 10 that rotates in an arc shape and an arc that the rotor 10 rotates. And a stator 20 having a plurality of slots 30 provided in a row facing the rotor 10 along an arc.

  A coil 40 is wound around the slot 30. The coil 40 includes an exciting coil 42 that is wound in an adjacent slot 30 so as to be reversely wound and generates a magnetic field by an electric current, and a detection coil 41.

  The detection coil 41 includes a sin wave detection coil wound around every other slot 30 from the end, a cos wave detection coil wound around the slot 30 where the sin wave detection coil is not wound, Is provided.

  When the excitation signal sin ωt is excited in the excitation coil 42, when the rotor 10 approaches the slot 30, the angle from the home position of the rotor 10 to the rotor 10 is θ, and the sin wave detection coil detects sin θ sin ωt and cos wave. A signal of cos θ sin ωt is generated from the coil. The R / D converter determines θ from the combination of sin θ sin ω and cos θ sin ωt.

  Further, the arc-shaped angle sensor of the present embodiment includes a sub-coil 43 that is wound around the slots 30 except for the slots 30 at both ends in a direction opposite to the exciting coil 42 and generates a magnetic field by an electric current.

  When the exciting coil 42 is wound in the CW (clockwise: forward rotation) direction, the auxiliary coil 43 is wound in the reverse CCW (counterclockwise: reverse rotation) and excited. This means that when the coil 42 is wound around the CCW, the auxiliary coil 43 is wound around the CW.

  When the sin wave detection coil and the cos wave detection coil are wound around the slots at both ends, the output voltages from the sin wave detection coil and the cos wave detection coil cause the above-described offset. Here, it is possible to suppress the offset by winding the sub coil 43 so as to generate a magnetic field opposite to the offset direction.

  Furthermore, the arc-shaped angle sensor of the present embodiment uses the number of turns of the sin wave detection coil and the cos wave detection coil in the slots 30 at both ends, and the number of turns of the sin wave detection coil and the cos wave detection coil in the slots 30 other than both ends. Do more.

  It is desirable to increase the number of turns to be a sufficient number of turns to cancel out the leakage of magnetic flux. Specifically, when the number of turns of the detection coil other than the slots at both ends is 100 turns, and the output reduction rate of the detection coil at the slots at both ends is 4%, the number of turns to be increased is 2 to 10 turns. Desirable, more preferably 4 turns.

  Since the sin wave detection coil and the cos wave detection coil in the slots 30 at both ends do not have a reversely wound sin wave detection coil and a cos wave detection coil adjacent to each other, the magnetic flux leaks. For this reason, the output voltages of the sin wave detection coil and the cos wave detection coil in the slots 30 at both ends are lowered. Therefore, the sine wave detection coil and the cosine wave detection coil in the slots 30 at both ends are wound as much as this decrease to suppress the decrease in the output voltage.

Here, the number of turns of each coil will be described. In the arc-shaped angle sensor of this embodiment, n is the number of slots 30, E is the number of turns of the sin wave detection coil and the cos wave detection coil in the slots 30 at both ends, S is the number of turns of the subcoil 43, and M is both ends. When the number of turns of the sin wave detection coil and the cos wave detection coil in the slot 30 other than the slot 30 is an arbitrary natural number,
E = M + k
S = E / {(n-2) / 2}
It is characterized by being.

  For example, the number of slots 30 is 10, the number of turns of the sin wave detection coil and the cos wave detection coil in the slots 30 other than both ends is 100 turns, and the sin wave detection coil and the cos wave detection in the slots 30 at both ends are detected. It is assumed that the number of turns of the coil for use is 104 turns. At this time, the number of turns of the auxiliary coil 43 is 26 turns.

  As described above, the arc-shaped angle sensor and the method for improving the accuracy of the arc-shaped angle sensor according to the present embodiment include the auxiliary coil 43 that generates a magnetic field by current in the slots 30 except for the slots 30 at both ends, and the slots at both ends. The number of turns of the 30 sin wave detection coils and the cos wave detection coil was made larger than the number of turns of the sin wave detection coils and the cos wave detection coils of the slots 30 other than both ends. Therefore, the arc-shaped angle sensor and the method for improving the accuracy of the arc-shaped angle sensor according to the present embodiment suppress the offset and suppress the decrease in the output voltage of the sin wave detection coil and the cos wave detection coil in the slots 30 at both ends. In addition, the angle detection accuracy in the slots at both ends is improved.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

It is the figure which showed the circular arc type angle sensor of this embodiment. It is the figure which showed the circular arc type angle sensor whose number of slots is ten. It is the figure which showed the case where the coil for a detection was wound around the slot of both ends.

Explanation of symbols

10: Rotor,
20: stator,
30: Slot,
40: coil,
41: detection coil,
42: Excitation coil,
43: Secondary coil.

Claims (4)

A rotor formed of an electromagnetic steel plate and rotated in an arc shape;
A stator that has a plurality of slots that are curved along an arc in which the rotor rotates, and that are provided in a row in opposition to the rotor along the arc;
An exciting coil that is wound so as to be reversely wound in the adjacent slots and generates a magnetic field by an electric current;
A sin wave detection coil wound around every other slot from the end;
A cos wave detection coil wound in a slot in which the sin wave detection coil is not wound;
In the slot excluding the slots at both ends, a secondary coil that is wound in a reverse direction to the excitation coil and generates a magnetic field by current,
An arc-shaped angle sensor comprising:   The number of turns of the sin wave detection coil and the cos wave detection coil in the slot at both ends is greater than the number of turns of the sin wave detection coil and the cos wave detection coil in the slot other than both ends. The arc-shaped angle sensor according to claim 1. When n is the number of slots, E is the number of turns of the sin wave detection coil and the cos wave detection coil of the slots at both ends, and S is the number of turns of the sub-coil,
The number of turns S of the secondary coil is
S = E / {(n-2) / 2}
The arc-shaped angle sensor according to claim 2, wherein A rotor formed of an electromagnetic steel plate and rotated in an arc shape;
A stator that has a plurality of slots that are curved along an arc in which the rotor rotates, and that are provided in a row in opposition to the rotor along the arc;
An exciting coil that is wound so as to be reversely wound in the adjacent slots and generates a magnetic field by an electric current;
A sin wave detection coil wound around every other slot from the end;
An arc-shaped angle sensor comprising: a cos wave detection coil wound in a slot in which the sin wave detection coil is not wound;
By providing a sub-coil wound in the opposite direction to the excitation coil in the slots except for the slots at both ends, the output voltages of the sin wave detecting coil and the cos wave detecting coil in the slots other than both ends Suppress the increase,
By increasing the number of turns of the sin wave detection coil and the cos wave detection coil in the slots at both ends than the number of turns of the sin wave detection coil and the cos wave detection coil in the slots other than both ends, Suppressing a decrease in output voltage of the sin wave detection coil and the cos wave detection coil of the slot,
An arc-shaped angle sensor characterized by that.

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