JPH0647805U - Rotation angle detector - Google Patents

Abstract

(57) [Summary] [Purpose] Even if an eccentric rotor is adopted, the rotation balance is improved and vibration is suppressed. [Configuration] Excitation magnetic poles A to D around which the excitation windings 2 and 3 are wound
And the eccentric rotor 10 in which the reluctance of the magnetic path passing through the exciting magnetic pole changes according to the rotational angle. In the apparatus, the eccentric rotor 10 is provided with balancing means for making the rotor center of gravity O and the center of rotation O ′ substantially coincide with each other. [Effect] Even if the eccentric rotor is adopted, the rotation balance becomes good, and the vibration due to the rotation of the rotor can be suppressed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a variable reluctance type rotation angle detection device having an eccentric rotor, and more particularly to a rotation balance structure for an eccentric rotor.

[0002]

[Prior art]

 A variable reluctance type rotation angle detecting device having an eccentric rotor of this type is conventionally known, for example, as disclosed in Japanese Patent Publication No. 62-58445. That is, as shown in FIGS. 4 and 5, four exciting magnetic poles A, B, C, and D are provided in the inner peripheral portion of the hollow cylindrical stator 1 so as to protrude toward the center. Has been done. Excitation windings 2 and 3 are differentially wound around the excitation magnetic poles A and C and B and D. A rotor 5 that rotates integrally with the rotating shaft 4 is opposed to the inner peripheral ends of the excitation magnetic poles A, B, C, and D with an appropriate gap interposed. A rotation angle θ to be detected is given to the rotation shaft 4. The rotor 5 shifts a position O ′ deviated by a predetermined amount from the shape center O of the rotor 5 itself so that the reluctance of the magnetic path passing through the exciting magnetic poles A, B, C and D is changed according to the rotation angle θ. It has a cylindrical shape with a rotation shaft 4 attached as a center of rotation.

Further, a detection winding 6 is wound around each of the exciting magnetic poles A, B, C and D by being connected to the stator 1 in series and wound around the exciting magnetic poles A, B, C and D, respectively. A composite signal E of induced voltages is taken out. The exciting winding 2 wound around the exciting magnetic poles A and C and the exciting winding 3 wound around the exciting magnetic poles B and D respectively have an AC signal for excitation with a phase difference of 90 degrees. Is applied from the oscillators 7 and 8. When the rotor 5 rotates in this state, a change in the reluctance is brought to each exciting magnetic pole A, B, C, D by the change in the gap between each exciting magnetic pole A, B, C, D, and the detecting winding 6 is caused. The combined signal E of the AC voltage having a phase shift corresponding to the rotation angle θ of the rotor 5 is extracted. By inputting this combined signal E to a rotation angle / electrical phase angle transducer (not shown), the rotation angle based on the phase shift of the combined signal E is obtained.

[0004]

[Problems to be solved by the device]

 The above-described conventional rotation angle detection device uses an eccentric rotor as the rotor in order to change the reluctance of the magnetic path passing through each exciting magnetic pole of the stator in accordance with the rotation angle, and therefore the rotation balance is poor. There was a problem that vibration occurred during rotation. There is also a problem that this vibration has a bad influence such as shortening the life of the bearing means such as ball bearing for supporting the rotary shaft integral with the rotor.

The present invention has been made to solve such a problem, and provides a rotation angle detection device capable of suppressing vibration by improving rotation balance even if an eccentric rotor is adopted as the rotor. The purpose is to do.

[0006]

[Means for Solving the Problems]

 The present invention provides an exciting magnetic pole around which an exciting winding is wound, a stator provided with a detecting winding for extracting an induced voltage due to the exciting magnetic pole, and the reluctance of a magnetic path passing through the exciting magnetic pole at a rotation angle. A rotation angle detection device comprising a substantially disk-shaped eccentric rotor that changes in accordance with the above, wherein the eccentric rotor is provided with a balance means for substantially matching the rotor center of gravity and the rotation center. It is characterized by forming a hole or groove in the eccentric rotor as a balancing means.

[0007]

[Action]

 If the eccentric rotor is provided with the balance means for substantially matching the center of gravity of the rotor and the center of rotation, the rotation balance becomes good even if the eccentric rotor is adopted, and vibration due to rotation of the rotor is suppressed.

[0008]

【Example】

 Hereinafter, an embodiment of a rotation angle detecting device according to the present invention will be described with reference to the drawings. 1 and 2, the eccentric rotor 10 is composed of a rotor 11 formed in a substantially cylindrical shape and a rotating shaft 12. The rotor 11 is made of, for example, a magnetic material such as a silicon steel plate having a good magnetic permeability. Further, the rotating shaft 12 is fitted and fixed in a through hole formed at a rotation center O ′ which is deviated from the center of gravity O of the rotor 11 by a predetermined distance, and both ends thereof are supported by bearing means such as ball bearings not shown. ing.

On the outer peripheral side of the rotor 11, a hole 13 as a balancing means is formed so as to penetrate in the axial direction. The hole 13 is set at an appropriate position and size such that rotational vibration does not occur when the rotor 11 is rotated about the rotation shaft 12 as a rotation center. An example thereof will be described with reference to FIG. In the example of FIG. 2, the outer diameter of the rotor 11 is set to 19.8 mm, the inner diameter is set to 10 mm, and the eccentricity is set to 0.5 mm. When no balancing means was applied, the center of mass of this rotor 11 was -0.1893, but as shown in FIG. 2, a hole 13 having a diameter of 2.76 mm was formed at a position of 7 mm on the right side. In this case, the center of mass of the rotor 11 approaches -0.0018 as close as possible to 0, indicating that the balance is good. That is, the position of the center of gravity of the rotor 11 and the center of rotation of the rotating shaft 12 are made to substantially coincide with each other.

FIG. 3 shows an example in which a plurality of holes 14 as a balancing means are formed on the outer peripheral side of the rotor 11. Also in this example, the position of the center of gravity of the rotor 11 and the rotation center of the rotation shaft 12 are configured to substantially coincide with each other. As such a balancing means, a groove may be formed in addition to the above holes, but the rotor 11 has a function as a magnetic path passing through the exciting magnetic poles as described above. Therefore, it is necessary to consider the position and size so as not to lose such yesterday, that is, to prevent the magnetic path in the rotor 11 from being distorted.

The eccentric rotor 10 configured as described above is mounted on the rotation angle detecting device shown in FIG. 4, and similarly to FIG. 4, the exciting magnetic poles A, B, C, D associated with the rotation of the rotor 11 are excited. A change in the gap between the two causes reluctance changes to the excitation magnetic poles A, B, C, D, and a combined signal of the AC voltage with a phase shift corresponding to the rotation angle θ of the rotor 11 from the detection winding 6. E is taken out. Further, the combined signal E can be input to the rotation angle / electrical phase angle transducer to obtain the rotation angle based on the phase shift of the combined signal E. At this time, even if the eccentric rotor 10 rotates at a high speed, the rotational balance is good, so that rotational vibration is suppressed and stable rotation is continued.

It should be noted that the above-described embodiment is merely an example. Although the eccentric rotor is formed in a cylindrical shape, a rotor having a structure in which, for example, pole teeth are projected on the outer peripheral portion so that the center of gravity and the center of rotation are deviated However, the configuration may be similar to that of the above-described example, and various modifications can be made without departing from the scope of the present invention.

[0013]

[Effect of device]

 As is apparent from the above description, the rotation angle detection device of the present invention is provided with the balance means for substantially aligning the center of gravity of the rotor with the center of rotation of the eccentric rotor. Therefore, there is an advantage of suppressing the vibration due to the rotation of the rotor.

[0014]

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a rotation angle detecting device according to the present invention.

FIG. 2 is a sectional view of an eccentric rotor of the same apparatus.

FIG. 3 is a perspective view showing another embodiment of the present invention.

FIG. 4 is a plan view showing a conventional rotation angle detection device.

FIG. 5 is a perspective view showing an eccentric rotor of the conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 stator 2,3 excitation winding 6 detection winding 10 eccentric rotor 11 rotor 12 rotating shaft 13 hole A to D exciting magnetic pole 0 center of gravity 0'rotation center

Claims (2)

[Scope of utility model registration request] 1. A stator provided with an exciting magnetic pole around which an exciting winding is wound, a detecting winding for extracting an induced voltage by the exciting magnetic pole, and a reluctance of a magnetic path passing through the exciting magnetic pole are rotated by a rotation angle. A rotation angle detection device including a substantially disk-shaped eccentric rotor that changes in accordance with the above, wherein the eccentric rotor is provided with a balance unit that substantially matches a rotor center of gravity and a rotation center. 2. The rotation angle detecting device according to claim 1, wherein the balance means provided in the eccentric rotor comprises a hole or a groove formed in the eccentric rotor.