JP3505164B2 - Angle detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angle detector, and more particularly to a variable reluctance (VR) type angle detector capable of detecting a magnetic pole position and a rotation amount of a motor.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional VR type angle detector.
Is a ring-shaped case, 2 is a plurality of, for example, eight stator magnetic poles projecting radially inward from the inner periphery of the case 1, 3 is a plurality of pole teeth formed at the tip of the stator magnetic pole 2, and 4 is a A stator coil wound around each stator magnetic pole 2 is a rotor,
Reference numeral 6 is n small teeth formed on the outer circumference of the rotor 5, and 7 is a rotor shaft.

In such a VR type angle detector, the angle (position) is detected by utilizing the fact that the inductance of the stator coil 4 wound around the stator magnetic pole 2 changes.

Assuming that the inductance is L, the number of windings of the stator coil is N, and the magnetic resistance of the magnetic circuit is R, L = N ² /
It is shown as R, and it can be seen that the inductance L changes with the magnetic resistance R. Further, since the magnetic resistance R changes depending on the gap between the stator pole teeth and the rotor small teeth, the inductance L has a fixed component Lo and a variation component Lv. If the rotational electrical angle is θ, L = Lo
It is expressed as + Lvsin θ. The sinusoidal change is obtained by appropriately designing the gap between the rotor teeth and the pole teeth of the stator poles facing each other and the tooth shape. The above-mentioned sinusoidal variation Lv
Angle detection is performed by detecting sin θ.

[0005]

Motors used in industrial machines are being reduced in diameter because they are arranged in a limited space. However, in the conventional angle detector as described above, the stator magnetic pole 2 is lengthened by the space for winding the stator coil 4, and there is a limit in reducing the diameter of the angle detector. Since the number of teeth is small, the inductance change amount Lv is small, and the detection output level is low, there are drawbacks such as poor detection accuracy. Further, when the diameter is forcibly reduced, the problem of the winding of the stator coil and the problem of interference between adjacent phases due to the annular stator due to the existence of the stators of each phase on the same plane increase.

The present invention is to solve the above problems, and in particular, the stator forming one phase uses the entire one plane,
To provide a magnetic pole position detector capable of achieving high accuracy by arranging the number of pole teeth of one phase the same as the number of small teeth of the rotor and conversely increasing the amount of inductance change that decreases with the conventional structure due to the smaller diameter. With the goal.

[0007]

The angle detector of the present invention comprises:
A rotor having a plurality of small teeth formed on its outer circumference and a plurality of stator pole teeth facing the rotor small teeth with a gap on its inner peripheral surface. The annular stator, the two stator coils, and the opposing surfaces in the axial direction
S concave and is become more and two annular magnetic body, the axially inner end face of the outer peripheral portion of each annular magnetic body is in contact with the axially outer end face of each said respective annular stator, an intermediate of the respective annular magnetic body Concave
Said stator coils are respectively disposed in the section, each ring
The axially inner end surface of the inner peripheral portion of the magnetic body is opposed to the axially outer end surface of the rotor through a gap, respectively.

In the angle detector of the present invention, a cylindrical portion extending in the axial direction is formed on the outer end surface of the inner peripheral portion of the rotor,
The inner peripheral surface of the annular magnetic body is opposed to the outer peripheral surface of the cylindrical portion with a gap.

Further, the angle detector of the present invention has a rotor having a plurality of small teeth formed on the outer periphery thereof, and a plurality of stator pole teeth which are opposed to the rotor small teeth with a gap therebetween. The axially spaced p sets of two annular stators axially separated from each other, the stator coils sandwiched between the two annular stators of each set, and the stators of each set. Magnetically connect the outer peripheral surface of the coil and the two annular stators 1
It is characterized by comprising a magnetic material for forming a stator part set of phases.

Further, the angle detector of the present invention has a rotor having a plurality of small teeth formed on the inner circumference thereof, and a plurality of stator pole teeth which are opposed to the rotor small teeth with a gap therebetween. The two annular stators axially separated from each other, the two stator coils, and the axially opposed surfaces are concave.
More become a two annular magnetic body consisting Jo, the axially inner end face of the inner peripheral portion of each annular magnetic body is in contact with the axially outer end face of each said respective annular stator, an intermediate of the respective annular magnetic body said stator coils are respectively disposed in a recess, each annular magnetic
The axially inner end surface of the outer peripheral portion of the body is opposed to the axially outer end surface of the rotor through a gap, respectively.

In the angle detector of the present invention, a cylindrical portion extending in the axial direction is formed on the outer end surface of the outer peripheral portion of the rotor,
The outer peripheral surface of the annular magnetic body is opposed to the inner peripheral surface of the tubular portion with a gap.

Further, the angle detector of the present invention has a rotor having a plurality of small teeth formed on the inner circumference thereof, and a plurality of stator pole teeth which are opposed to the rotor small teeth with a gap therebetween. The axially spaced p sets of two annular stators axially separated from each other, the stator coils sandwiched between the two annular stators of each set, and the stators of each set. Magnetically connect the inner peripheral surface of the coil and the two annular stators 1
It is characterized by comprising a magnetic material for forming a stator part set of phases.

The side surface of the magnetic body between the annular stators has a partial opening, and the stator coil fixed to the printed wiring board communicates with the opening between the two annular stators. It is characterized by being arranged in space.

The printed wiring boards to which the p sets of stator coils are fixed are connected to each other.

The annular stator and the magnetic body between the annular stators are integrally formed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings.

A first embodiment of the present invention is shown in FIG. In the present invention, two annular stators 9 each having a plurality of stator pole teeth 8 formed on the inner peripheral surface thereof are formed so as to be spaced apart from each other in the axial direction. 90 ° in electrical angle to
The two stators 9 are displaced from each other, and the two stators 9 are connected to each other by the ring-shaped case 1, and the stator pole teeth 8 are formed on the outer periphery of the rotor 10 in the same number as the stator pole teeth 8.
Are opposed to each other with a gap.

Further, the axial inner end surfaces of the outer peripheral portion of the annular magnetic body 12 are magnetically connected to the axial outer end surfaces of the respective annular stators 9 and fixed to the central portions of the annular magnetic bodies 12, respectively. The child coil 13 is arranged so that the axial inner end surface of the inner peripheral portion of each annular magnetic body 12 is opposed to the axial outer end surface of the rotor 10 with a gap therebetween.

In the second embodiment of the present invention, as shown in FIG. 1, a cylindrical portion 14 extending in the axial direction is formed on the outer end surface of the inner peripheral portion of the rotor 10, and the outer peripheral surface of this cylindrical portion 14 is formed. Then, the inner peripheral surface of the annular magnetic body 12 is made to face each other through a gap.

In the first and second embodiments of the present invention, one stator coil 13 has an A phase and the other stator coil 13 has a B phase, and the one and the other stator coils 13, 13 are provided. The magnetic flux generated by exciting the magnet with a constant current I having an angular frequency ω is generated from the inner peripheral portion of the annular magnetic body 12 to the rotor 1
0 flows in the axial direction to the rotor small teeth 11, and further to the annular stator 9 through the stator pole teeth 8 to return to the outer peripheral portion of the annular magnetic body 12. As a result, each stator coil 13,
From A, voltage outputs of A phase and B phase are obtained. The voltage is V
o, the resistance of the stator coil is r, and the excitation angular frequency is ω
Then, output voltage signals Voa and Vob are obtained.

[0021] Voa = Isinωt (r + ωLo + ωLvsinθ)

[0022] Vob = Isinωt (r + ωLo + ωLvcosθ)

By processing the output voltage signal, r, ωLo
If the two-phase signals of sin and cos are obtained with respect to the rotational electrical angle θ, the rotational electrical angle θ can be detected.

In the third embodiment of the present invention, the two annular magnetic bodies 12 are not used as shown in FIG. 2, but instead, the two annular stators 9a and 9b are separated from each other in the axial direction. ,
The air core stator coil 1 is provided between the annular stators 9a and 9b.
5, the outer peripheral surface of the stator coil 15 and the two annular stators 9a and 9b are magnetically coupled by the annular magnetic body 16 to form two sets spaced apart from each other in the axial direction. The magnetic poles 8 of the two sets of stators are displaced from each other at an electrical angle of 90 ° in the circumferential direction and are formed on the outer circumference of the rotor 10, and the same number of rotor small teeth 11 as the stator pole teeth 8 are attached to the stator. The pole teeth 8 are arranged to face each other with a gap.

In the third embodiment of the present invention, one air core stator coil 15 is the A phase and the other air core stator coil 15 is the B phase, and the one and the other air core stators are A magnetic flux generated by exciting the coils 15 and 15 with a constant current power source of a constant frequency generates a magnetic substance 16 and an annular stator 9a.
Through the stator pole teeth 8 and further through rotor small teeth 11
Through the annular stator 9b and return to the magnetic body 16 on the outer circumference of the air-core stator coil 15. As a result, from each air core stator coil 15,15,
A-phase and B-phase voltage outputs can be obtained, and the rotational electrical angle θ can be detected by the signal processing circuit as in the above embodiment. Further, in the third embodiment, the change in the magnetic resistance R can be made larger than in the other embodiments, and the detection accuracy is improved.

A fourth embodiment of the present invention is shown in FIG. In the fourth embodiment, the air-core stator coils 15 and 15 are fixed to the flexible substrate 17, and the lead wires of the air-core stator coil are soldered on the wiring pattern of the flexible substrate 17 to form the air-core stator coil. The wires 15 and 15 are also connected at the same time, these two flexible boards 17 are integrally connected to each other, and the annular magnetic body 16 and the side surface of the case 1 have an opening portion into which the air core stator coil 15 can be inserted. 18 is formed.

According to the fourth embodiment, not only the workability is improved, but also before the air-core stator coil is inserted, the pole teeth on the inner circumference of the stator are stacked to improve the roundness of the pole teeth on the inner circumference of the stator. Can be machined, and the accuracy of the detector can be improved.

A fifth embodiment of the present invention is shown in FIG. With respect to the third embodiment shown in FIG. 2 that is the inner Rota structure The fifth embodiment is obtained by the outer rotor structure, the inner periphery of the teeth 11 of the rotor 10 of the rotor 10 The stator pole teeth 8 are provided on the outer circumference of the stators 9a and 9b, and the fixed shaft 19 supporting the stator is attached to the case 1 via the fixed plate 20.

The characteristics of the fifth embodiment are the same as those of the third embodiment.

[0030] Incidentally, in the embodiment shown in FIG. 1 in the same manner Lee
It is of course a runner Rota structure may be used as the outer Rota structure.

Further, even if the annular stator 9 and the annular magnetic body 12 in FIG. 1 and the annular stators 9a and 9b and the magnetic body 16 in FIG. The characteristics of are obtained.

[0032]

Since the angle detector of the present invention has the above-mentioned structure, the following effects can be obtained.

1. The stator coil is arranged not in the same plane with respect to the rotor small teeth and the stator pole teeth but in the axial direction, so that the diameter can be reduced.

2. Since the phase coils are not arranged on the same plane, the disturbance due to the mutual induction action between the phase coils can be remarkably improved.

3. Since one phase is formed with pole teeth on the inner or outer circumference of the stator, mechanical runout of the rotor, small rotor teeth,
The accuracy of the stator pole teeth and the variation of the air gap between the rotor and the stator are all averaged, and the error becomes very small.

4. It is easy to make multiple phases by stacking units.

5. The air core stator coil wound independently can be easily miniaturized.

6. The workability can be remarkably improved by fixing the multi-phase air core stator coil to the flexible substrate and electrically connecting them.

7. Finishing machining of p sets of stators is possible in advance, and accuracy and workability can be improved by inserting the stator coils from the direction perpendicular to the axis.

Although the above-described embodiments of the present invention are all two-phase angle detecting devices, it is needless to say that they can be used as a multi-phase angular position detecting device of three or more phases.

[Brief description of drawings]

FIG. 1 is an explanatory view of first and second embodiments of an angle detector of the present invention.

FIG. 2 is an explanatory view of a third embodiment of the angle detector of the present invention.

FIG. 3 is an explanatory view of a fourth embodiment of the angle detector of the present invention.

FIG. 4 is an explanatory view of a fifth embodiment of the angle detector of the present invention.

FIG. 5 is an explanatory diagram of a conventional angle detector.

[Explanation of symbols]

1 ring-shaped case 2 Stator magnetic pole 3 pole teeth 4 Stator coil 5 rotor 6 small teeth 7 rotor shaft 8 stator pole teeth 9 Annular stator 9a Annular stator 9b Annular stator 10 rotor 11 rotor small teeth 12 annular magnetic material 13 Stator coil 14 Cylindrical part 15 Air core stator coil 16 annular magnetic material 17 Flexible substrate 18 openings 19 fixed axis 20 Fixed plate

Front page continuation (72) Inventor Yasuo Matsuda 3-93 Aioi-cho, Kiryu-shi, Gunma Japan Servo Co., Ltd. Research Institute (72) Inventor Masafumi Yamamoto 5-8-45 Enami, Saitama City, Saitama Japan Servo Research Institute Co., Ltd. (56) Reference JP-A-7-190710 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01B 7/30 101 G01D 5/00-5/252 G01D 5/39-5/62

Claims (9)

(57) [Claims] 1. A rotor having a plurality of small teeth formed on its outer circumference,
Two annular stators axially separated from each other, which have a plurality of stator pole teeth on the inner peripheral surface thereof that face the rotor small teeth with a gap, and two stator coils, Axial direction
Facing surface of the direction is made more and two annular magnetic body is respectively concave, axially inner end face of the outer peripheral portion of each annular magnetic body is in contact with the axially outer end face of each said respective annular stator, each Annular magnet
The stator coils are respectively arranged in the recesses in the middle of the body , and the axial inner end surfaces of the inner peripheral portions of the annular magnetic bodies are respectively opposed to the axial outer end surfaces of the rotor through the gaps. An angle detector characterized in that 2. A cylindrical portion extending in the axial direction is formed on an outer end surface of an inner peripheral portion of the rotor, and an inner peripheral surface of the annular magnetic body is opposed to an outer peripheral surface of the cylindrical portion with a gap. The angle detector according to claim 1, wherein: 3. A rotor having a plurality of small teeth formed on its outer circumference,
The axial p sets of two annular stators axially separated from each other, each having a plurality of stator pole teeth opposed to the rotor small teeth with a gap in its inner peripheral surface, 2 of a set
The stator coils sandwiched between the respective annular stators, the outer peripheral surfaces of the stator coils of each set and the two annular stators are magnetically coupled to form a stator portion set for one phase. An angle detector comprising a magnetic material for forming. 4. A rotor having a plurality of small teeth formed on its inner circumference,
Two annular stators axially separated from each other, having a plurality of stator pole teeth opposed to the rotor small teeth with a gap on the outer peripheral surface thereof, two stator coils, and a shaft. Person
Facing each other, each of the annular magnetic bodies has a concave shape, and the axial inner end surface of the inner peripheral portion of each annular magnetic body contacts the axial outer end surface of each annular stator. Each ring magnet
The stator coils are respectively arranged in the recesses in the middle of the body, and the axial inner end faces of the outer peripheral portions of the annular magnetic members are respectively opposed to the axial outer end faces of the rotor through gaps. An angle detector characterized in that 5. A cylindrical portion extending in the axial direction is formed on the outer end surface of the outer peripheral portion of the rotor, and the outer peripheral surface of the annular magnetic body is opposed to the inner peripheral surface of the cylindrical portion with a gap. The angle detector according to claim 4, wherein: 6. A rotor having a plurality of small teeth formed on its inner circumference,
The axial p sets of two annular stators axially separated from each other, which have a plurality of stator pole teeth opposed to the rotor small teeth with a gap on the outer peripheral surface thereof, and the above-mentioned sets. Of 2
The stator coils sandwiched between the respective annular stators, and the inner peripheral surfaces of the stator coils of each set and the two annular stators are magnetically connected to each other to form a stator part set for one phase. An angle detector comprising a magnetic material for forming the angle detector. 7. The two annular stators, wherein a side surface of the magnetic body between the annular stators has a partial opening, and the stator coil fixed to a printed wiring board communicates with the opening. The angle detector according to claim 3, wherein the angle detector is arranged in a space between them. 8. The angle detector according to claim 7, wherein the printed wiring boards to which the p sets of stator coils are fixed are connected to each other. 9. The magnetic material between the annular stator and the annular stator is integrally formed.
The angle detector according to 1, 3, 4 or 6 .