JPH0819221A - Electric motor - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a thin electric motor that does not catch an accurate signal of a sensor magnet at the time of starting the electric motor and incorporates countermeasures against starting failure due to an abnormal signal due to magnetic flux of the winding. [Structure] The magnetic flux sensor is installed in the center of the pole where the magnetic flux distribution of the stator with the winding is small. According to the present invention, it is possible to install a magnetic speed sensor on a stator provided with windings without lowering the output of the electric motor and obtain a thin electric motor with good speed accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an installation place of a magnetic sensor for detecting the rotation speed of an induction motor.

[0002]

2. Description of the Related Art In recent years, in motors such as induction motors, the demand for speed control has increased, and a magnet provided in a rotor is rotated together with the rotor, and a change in the magnetic flux is detected by a magnetic speed sensor installed in the stator. Many things are controlling.

On the other hand, there is an increasing demand for thinner electric motors in order to reduce the thickness and weight of products, and it is necessary to incorporate a magnetic velocity sensor into the electric motor.

A method of installing such a conventional magnetic velocity sensor will be described with reference to FIG. FIG. 4 shows an example of an induction motor with two poles. The magnetic speed sensor 1 is installed in the intermediate portion between the main winding 2 and the auxiliary winding 18, and is connected to the motor output wire 4 on the printed circuit board 3. It was

[0005]

However, in the above-mentioned conventional structure, when the boundaries of the magnetization (N and S poles) of the sensor magnets provided on the rotor at the time of starting the motor and the position of the magnetic velocity sensor 1 coincide with each other, If the applied voltage is low and the motor does not start within a certain period of time, and if the voltage applied to the motor is high and the amount of magnetic flux in the winding is higher than the amount of magnetic flux in the sensor magnet, the magnetic speed sensor 1 outputs an abnormal pulse and the motor stops. The product control may determine that the motor is rotating regardless of the state, and the applied voltage may be reduced to prevent the motor from starting. For this reason, a method of making a product control system that does not use the signal of the magnetic velocity sensor 1 at the time of startup and a method of making the magnetic flux amount of the sensor magnet higher than the magnetic flux amount of the winding are available. There was a problem that the range of use was restricted and it hindered model development.

[0006]

In order to solve the above conventional problems, the present invention installs the magnetic velocity sensor 1 at a position where the magnetic flux distribution of the stator is small.

[0007]

With this configuration, it is possible to provide a high-performance electric motor that is compact and has a wide range of use without the magnetic speed sensor 1 outputting an abnormal pulse when the electric motor is started and the electric motor not starting.

[0008]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a completed winding product showing an installation position of a magnetic velocity sensor 1 according to an embodiment of the present invention.
The magnetic velocity sensor 1 is installed at the pole center where the distribution of the magnetic flux of the main winding 2 is small, and is connected to the motor output wire 4 on the printed circuit board 3.

FIG. 2 is a half sectional view of a phase control induction motor using the present invention. Reference numeral 5 denotes a stator finished product, which includes a stator core 6, windings 7, resin 8, and a magnetic velocity sensor 1. Numeral 9 is a rotor finished product, and a speed detecting magnet 10,
It is composed of a rotor 11 and a rotary shaft 12. The rotor finished product 9 is rotatably fixed to the stator finished product 5 via the bearing device 13.

The magnetic velocity sensor 1 is arranged at a position facing the velocity detecting magnet 10.

With the above construction, when the rotor finished product 9 rotates, the velocity detecting magnet 10 also rotates at the concentric velocity, and the magnetic velocity sensor 1 provided in the stator finished product 5 obtains a velocity signal.

Thus, as shown in FIG. 3, by inputting this speed signal 14 to the phase control circuit 15 and controlling the phase induction motor 17 with the output 16 of this phase control circuit 15, phase control with high speed accuracy is achieved. The induction motor 17 can be obtained.

[0014]

As is apparent from the above description, according to the present invention, since the magnetic velocity sensor 1 is installed at the pole center where the magnetic flux distribution of the winding is small, it is compact and has a wide range of use and good speed accuracy. An electric motor is obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of a completed winding product showing an installation position of a magnetic velocity sensor according to an embodiment of the present invention.

FIG. 2 is a half sectional view of a phase control induction motor in one embodiment of the present invention.

FIG. 3 is a block diagram of a phase control induction motor and a phase control circuit according to the present invention.

FIG. 4 is a perspective view of a completed winding product showing installation positions of conventional magnetic velocity sensors.

[Explanation of symbols]

 1 Magnetic Velocity Sensor 2 Main Winding 3 Printed Circuit Board 4 Motor Outlet Line 5 Stator Finished Product 6 Stator Core 7 Winding 8 Resin 9 Rotor Finished Product 10 Speed Detection Magnet 11 Rotor 12 Rotating Shaft 13 Bearing Device 14 Speed signal 15 Phase control circuit 16 Output 17 Phase control induction motor 18 Auxiliary winding

Claims (2)

[Claims] 1. An electric motor having a stator having a winding, a magnetic velocity sensor and a sensor magnet, wherein the magnetic velocity sensor is installed at a position where the magnetic flux distribution of the stator is small. 2. The electric motor according to claim 1, wherein the magnetic velocity sensor is installed at the pole center of the winding.