JPH09210725A - Resolver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resolver of little unbalance weight wherein eddy current is difficult to generate on the surface of a rotor. SOLUTION: Stator teeth 11 provided on the inner diameter side of a stator iron core 1 at specified polar pitches, an excitation coil wound around the stator tooth 11, a detection coil and a cylindrical rotor iron core 2 concentric with the stator iron core 1 are equipped. At this time a plurality of rotor teeth 21 are provided on the outer circumference of the rotor iron core 2 so that each width angle θi may be changed in the form of a cosine wave, and a shallow groove 22 is formed between the rotor teeth 21. Eddy current is controlled with the shallow rotor groove 22, and unbalance weight can be relatively lessened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable reluctance type resolver for detecting an angular position and a rotational speed.

[0002]

2. Description of the Related Art As a conventional technique, a sine wave is used for excitation 1
Phase excitation windings and three-phase detection windings with a phase difference shifted by 120 ° in terms of electrical angle are wound around teeth with a pole pitch of 60 ° and face each other with an air gap facing the inner diameter side of the stator. A magnetic cylindrical rotor is provided eccentrically, and when the rotor rotates, the reluctance is changed by changing the air gap value, and a variable
There is a reluctance type (hereinafter referred to as VR type) resolver (for example, Japanese Patent Laid-Open No. 1-218344, FIG. 3).

[0003]

However, since the surface of the rotor is flat, an eddy current is generated, which causes heat generation of the rotor, deterioration of efficiency, and deterioration of detection accuracy. Further, since the rotor is eccentrically provided, the rotor vibrates due to unbalanced weights during rotation, which is not suitable for high speed rotation. Therefore, the present invention is less likely to generate eddy currents on the surface,
An object of the present invention is to provide a resolver having a rotor with a small unbalanced weight.

[0004]

In order to solve the above problems, a plurality of rotor teeth having different width angles are provided on the outer circumference of a rotor core that is concentric with the stator core to change the air gap permeance into a cosine wave. A rotor groove is formed between them.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A stator tooth provided on an inner diameter side of a stator iron core with a predetermined pole pitch, an excitation winding and a detection winding wound around the stator tooth, and the stator tooth are opposed to each other through a gap. Further, in a resolver having a cylindrical rotor core provided concentrically with the stator core, a plurality of rotor teeth are provided on the outer periphery of the rotor core so that each width angle changes in a cosine wave shape. A rotor groove is formed between them. θs is the tooth width angle of the stator teeth, [] is the absolute value,
When i is the rotor tooth number (1 ·· n), the tooth width angle θi of the rotor tooth is θi = θs · [cos (2π · (i−
1) / n]. The rotor groove formed on the outer circumference of the rotor core suppresses the generation of eddy currents. Further, since the stator core and the rotor core are concentrically provided, the unbalance weight of the rotor is relatively small.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the drawings. FIG.
FIG. 3 is a sectional view showing a first embodiment of the present invention. On the inner diameter side of the stator core 1, a predetermined pole pitch (90 ° in the figure)
Thus, m (4 in the figure) stator teeth 11 having a tooth width angle θs are provided. Each of the stator teeth 11 has an α-phase winding Aα and a β-phase winding A with a phase difference of 90 ° in electrical angle.
A two-phase winding A consisting of β is concentratedly wound. Inside the two-phase winding A, the one-phase winding B is concentratedly wound. Stator teeth 1
On the inner diameter side of 1, a cylindrical rotor core 2 made of a magnetic material is provided concentrically with the rotation center O so as to face each other with a gap. On the outer periphery of the rotor core 2, the tooth width angle θi is different n
(> M) rotor teeth 21 are provided. The tooth width angle θi is expressed by the following equation (1). θi = θs · [cos (2π · (i−1) / n] (1) where [] is an absolute value and i is the rotor tooth number (1 ···
n). That is, on the outer circumference of the rotor core 2, n rotor teeth 21 whose tooth width angles θi continuously change at equal pitch angles θp (2π / n) are arranged radially around the rotation center O. Rotor grooves 22 having different widths are formed between the respective rotor teeth 21. Although exaggerated in the figure, the depth of the rotor groove 22 is not less than the depth (normally about 500 μm) at which the skin effect does not occur. As a result, when the rotor core 2 makes one rotation, the stator teeth 11
The rotor teeth 21 have the same width at any one position, and the rotor teeth 21 have different tooth widths at other positions.

The operation will be described below. In this example, the two-phase winding A is the excitation winding and the one-phase winding B is the detection winding.
It is a VR type resolver that detects one phase by exciting two phases. When the rotor core 2 makes one rotation, the permeance P of the air gap is, as shown in FIG. 2, the tooth width angle θs of the stator tooth 11 and the rotor tooth 2
The permeance P _U when the first width angle θi is equal to the upper limit, width angle θi of the rotor teeth 21 has a lower permeance P _L when minimal changes to the cosine wave having the n number of steps . As the number n of rotor teeth 11 increases, the permeance P changes more smoothly in a cosine wave shape. Each of the α-phase winding Aα and the β-phase winding Aβ of the two-phase winding A has a voltage V ₀ · sin with a phase difference of 90 ° in electrical angle.
When excited at (ω ₀ · t) and V ₀ · cos (ω ₀ · t), a voltage of V · cos (ω ₀ · t−ω) is induced in the one-phase winding B. PLL (Phase Rock Loop)
Etc. to detect the phase difference ω.

In the above description, the one-phase winding B is used as the detection winding and the two-phase winding A is used as the excitation winding. It is needless to say that the excitation may be performed by a one-phase sine wave or a cosine wave to induce a two-phase voltage in the two-phase winding A, and the description thereof will be omitted.

FIG. 3 is a sectional view showing a second embodiment of the present invention. In this example, the bottom 22b of the rotor groove 22 is provided on a circle having a radius r in which the center O ′ is slightly eccentric with respect to the rotation center O.
The portion with a large tooth width angle θi is deepened and the portion with a small tooth width angle θi is shallowed. By doing so, the imbalance of the rotor core 2 can be eliminated.

[0010]

As described above, according to the present invention, a plurality of rotor teeth having different width angles for changing the air gap permeance into a cosine wave are provided, and the rotor groove is formed between the rotor teeth.
The eddy current generated on the outer circumference of the rotor core is suppressed, and
Since the depth of the rotor groove can be made relatively shallow, there is an effect that the unbalance weight of the rotor core becomes relatively small.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a graph showing changes in void permeance according to the present invention.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

[Explanation of symbols]

 1 Stator Iron Core 11 Stator Teeth A Two Phase Winding Aα α Phase Winding Aβ β Phase Winding B 1 Phase Winding 2 Rotor Iron Core 21 Rotor Teeth 22 Rotor Groove

Claims (2)

[Claims] 1. A stator tooth provided on an inner diameter side of a stator iron core at a predetermined pole pitch, an excitation winding and a detection winding wound around the stator tooth, and the stator tooth facing each other through a gap, A resolver comprising a cylindrical rotor core provided concentrically with a stator core, wherein a plurality of rotor teeth are provided on the outer periphery of the rotor core so that each width angle changes in a cosine wave shape, and a rotor is provided between the rotor teeth. A resolver having a groove formed therein. 2. The bottom of the rotor groove is provided on a circle eccentric with respect to the center of rotation such that a portion having a large tooth width angle of the rotor tooth is deep and a portion having a small tooth width angle is shallow. The resolver according to Item 1.