JPH0250704B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radial gap type permanent magnet motor in which field magnetic poles are composed of permanent magnets.

Conventionally, when manufacturing permanent magnet motors with multiple field magnetic poles made of permanent magnets, such as DC brushless motors with permanent magnet field magnetic poles on the rotor side, which have different torque and speed characteristics. Usually, the method used is to change the number of armature coils on the stator side or the number of parallel branches of the armature coils. However, in such a permanent magnet motor, the stator has a wide variety of winding specifications, which makes it difficult to make the stator a common part, which makes parts management complicated. Also,
A permanent magnet motor that changes the magnetization conditions of the permanent magnet, that is, a permanent magnet that is magnetized to an unsaturated magnetic flux density region by adjusting the magnetization of the permanent magnet material, thereby reducing the total magnetic flux generated by the field magnetic pole. Permanent magnet motors have also been considered in which the quantity is set to a predetermined target value. However, this permanent magnet motor has the disadvantage that the magnetization characteristics of the permanent magnet fluctuate due to the armature coil starting force during motor operation, resulting in unstable torque and speed characteristics. When magnetizing to an unsaturated magnetic flux density region, the output adjustment work of the magnetizing device (that is, the work of setting the current flowing for magnetization) becomes delicate and complicated, and setting the torque/speed characteristics is troublesome. There is also the downside of uncertainty.

The present invention has been made in response to the above-mentioned circumstances, and its purpose is to be able to easily and reliably set the torque/speed characteristics, eliminate the risk of the torque/speed characteristics becoming unstable, and further The object of the present invention is to provide a permanent magnet motor that can obtain effects such as making it possible to prevent component management from becoming complicated.

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

FIG. 1 shows the overall structure of a radial gap type DC brushless motor 1 as a permanent magnet motor. In FIG. 1, a stator 2 is composed of a slotless core 3, a bobbin 4, and a multi-phase armature coil 5. A rotor 6 is composed of a rotating shaft 7, a rotor yoke 8, and a plurality of field magnetic poles 10 formed at predetermined pitches in the circumferential direction by providing permanent magnets 9 in a cylindrical shape on the inner peripheral surface of the rotor yoke 8. Reference numeral 11 denotes a printed wiring board fixed to the data 2, on which a drive circuit 13 including a magnetic sensor 12 for detecting the rotational position of the rotor 6 by leakage magnetic flux from the rotor 6 is disposed. The drive circuit 13 is configured to energize the plurality of phase armature coils 5 in a predetermined order according to the rotational position of the rotor 6 detected by the magnetic sensor 12. A torque is generated between the rotor 6 and the rotor 6.

Now, a method of setting the torque/speed characteristics in the DC brushless motor 1 as described above will be described below. That is, a magnetizing device 14 for the permanent magnet 9 is shown in FIG. In FIG. 2, 15 is a magnetizing yoke, which has a cylindrical main yoke 15a and an annular auxiliary yoke 15b located concentrically outside the main yoke 15a. An annular storage recess 15c is defined between the auxiliary yokes 15b. Reference numeral 16 denotes an adjustment ring removably disposed at the bottom of the storage recess 15c. Reference numeral 17 denotes a magnetizing coil housed in a slot (not shown) formed in the main yoke 15a, which is connected to the field magnetic pole 10.
They are arranged at pitches according to the number of magnetic fields. 18 is a magnetizer for supplying current to the magnetizing coil 17.

Therefore, in the magnetizing device 14 having the above configuration, the rotor yoke 8 is stored in the storage recess 15c together with the permanent magnet material 9A arranged annularly on the inner circumferential surface of the rotor yoke 8, for example on an assembly line, and the magnetizing coil 17 is placed in this stored state. There is a method that magnetizes the permanent magnet material 9A to the saturation magnetic flux density region by supplying current to the magnet. The upper end peripheral portion is made to protrude upward from the magnetizing yoke 15. Then, the permanent magnet 9 formed through the above magnetization process has an unmagnetized portion (see It is magnetized up to the magnetic flux density region. Therefore, each of the plurality of field magnetic poles 10 has an unmagnetized portion X at the upper end portion and a saturated magnetized portion occupying the other portion, which are divided in the axial direction. At this time, since the ratio occupied by the unmagnetized portion X can be arbitrarily changed by adjusting the height of the adjustment ring 16, as a result, the total amount of magnetic flux generated by each field magnetic pole 10 can be adjusted by such means. can be adjusted arbitrarily.

Here, since the DC brushless motor 1 has the property that its generated torque is approximately proportional to the magnetic flux of the field magnetic poles 10, and its rotational speed is approximately inversely proportional to the magnetic flux, each field is magnetic pole 1
By arbitrarily adjusting the total amount of magnetic flux generated at 0,
The torque/speed characteristics can be set as desired. In this case, since it is sufficient to magnetize the permanent magnet material 9A up to the saturation magnetic flux density region, there is no possibility that setting of the current to be applied for magnetization becomes delicate and complicated as in the conventional case. Further, since the permanent magnet 9 is magnetized to the saturation magnetic flux density region, there is no possibility that the magnetization characteristics of the permanent magnet 9 will be varied by the magnetomotive force of the armature coil 5. Moreover, even when manufacturing other types of DC brushless motors 1 with different torque and speed characteristics, the stator 2 can be used as a common part, and the rotor 6 can be combined with the rotor yoke 8 and the permanent magnet material 9.
When combined with A, it can be used as a single component, thus reducing the number of component types and facilitating component management.

As explained above, the radial gap type permanent magnet motor according to the present invention has saturation magnetization that is divided in the axial direction around the entire circumference of the field magnetic pole made of cylindrical permanent magnets and facing the armature coil. As a result of this feature, the torque/speed characteristics can be easily and reliably set, and the torque/speed characteristics can be easily and reliably set.
There is no risk that the speed characteristics will become unstable, and excellent effects can be obtained, such as making it possible to prevent component management from becoming complicated.

[Brief explanation of the drawing]

The drawings relate to one embodiment of the present invention.
The figure is a sectional view of a DC brushless motor, and FIG. 2 is a diagram illustrating the configuration of a magnetizing device. In the figure, 1 is a DC brushless motor, 2 is a stator,
5 is an armature coil, 6 is a rotor, 9 is a permanent magnet,
9A is a permanent magnet material, 10 is a field magnetic pole, and 14 is a magnetizing device.

Claims (1)

[Claims] 1. In a radial gap permanent magnet motor comprising an armature coil and a plurality of field magnetic poles, the plurality of field magnetic poles being constituted by cylindrical permanent magnets, a portion of each field magnetic pole facing the armature coil; 1. A permanent magnet motor characterized by having a saturation magnetized part and a non-magnetized part divided in the axial direction around the entire circumference of the motor.