JPH03212135A - Rotor with magnet for rotary electric machine - Google Patents

Abstract

PURPOSE:To make fine iron pieces to hardly adhere on a magnet by providing side plates made of a nonmagnetic material at both sides of a rotor core in such a manner that at least part of the side plate is present in the lateral width of a stator core. CONSTITUTION:Side plates 10 formed in a disclike state of a nonmagnetic material are engaged with a shaft 6 at both sides of a rotor core 7 to be brought into close contact with a magnet 9. Further, the core 7 is disposed partly at least in the thickness of the side plate 10 within the lateral width of a stator core 2. Iron pieces entered from an air hole 1a are discharged, since the sides of the core 7 are nonmagnetic, without being attracted thereto. The inlet of an air gap formed between the cores 2 and 7 is not charged with magnetism by the plates 10, and the pieces are not attracted to the outer periphery of the magnet 9. Accordingly, the iron pieces are not adhered to the rotor 5 thus eliminating its trouble.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotor with magnets that constitutes a rotating electrical machine, such as a brushless DC motor, and is provided with magnets on its outer periphery.

[Conventional technology]

The stator and rotor of a brushless DC motor are generally
It is configured as shown in the figure. In the figure, l is the cooling air hole 1a
2 is a stator core fitted into the frame 1, and 3 is a stator coil. A rotor 5 is composed of a shaft 6 whose one end serves as an output shaft end and a rotor core 7 fitted onto the shaft 6.The rotor core 7 has a core body 8 with magnets 9 fixed to its outer periphery. configured. An air gap is formed between the inner peripheral surface of the stator core 2 and the outer peripheral surface of the rotor 5, and the stator core 2 and the rotor 5 are formed to have the same width dimension.

The brushless DC motor rotates a rotated body connected to the shaft 6, and is cooled by outside air flowing through the air hole 1a.

[Problem to be solved by the invention]

By the way, as mentioned above, in the open type brushless DC motor having the air holes 1a, there is a concern that small pieces of iron or the like that enter with the cooling air may adhere to the magnet 9 and cause a failure.

An object of the present invention is to provide a rotor with magnets in which fine pieces of iron or the like are not easily attached to the magnets 9 in an open type brushless DC motor.

[Means to solve the problem]

In order to achieve the above object, according to the present invention, in a magnet-equipped rotor of a rotating electric machine having magnets on the outer periphery of a rotor core fitted to a shaft, side plates made of a non-magnetic material are provided on both sides of the rotor core. At least a portion of the thickness of the side plate shall be within the width of the stator core.

[Effect]

Non-magnetic side plates on both sides of the magnet prevent the iron piece from being attracted to the magnet. Therefore, the cause of failure can be eliminated.

〔Example〕

FIG. 1 shows an embodiment of the invention, and parts common or identical to those in FIG. 2 are designated by the same reference numerals.

In FIG. 1, reference numeral 10 denotes side plates made of a non-magnetic material in the shape of a disc and fitted onto the shaft 6 on both sides of the rotor core 7 so as to be in close contact with the side surfaces of the magnets 9. This side plate 1
0 is formed as a part of the rotor core 7 to have the same outer diameter as the magnet 9, and has a groove 11 running in the circumferential direction on the outer peripheral surface. Further, in this embodiment, the width of the rotor core 7 including the thickness of the side plate 10 is set within the width of the stator core 2 so that at least a part of the thickness of the side plate lO lies within the width of the stator core 2. It is formed to have the same dimensions as the width of the iron core 2.

In the above embodiment, the side plate 10 is fitted onto the shaft 6, but it can also be fixed onto the core body 8 using machine screws or the like.

FIG. 1 shows the brushless DC motor in its entirety, with reference numeral 13 a bracket, 14 a ball bearing, and 15 a blower which is directly connected to the brushless DC motor and serves as its load.

In the above-mentioned configuration, fine pieces of iron that have entered through the air holes 1a due to the operation of the brushless DC motor are discharged by the wind without being attracted to the side surfaces of the rotor core 7 because they are non-magnetic. The air gap formed between the stator core 2 and the rotor core 7 also has an inlet portion that is not magnetic due to the side plate 10, and the labyrinth effect of the grooves 11 causes the iron pieces to be attracted to the outer peripheral surface of the magnet 9. There is no. Therefore, the brushless DC motor is free from malfunctions due to iron pieces adhering to the rotor 5.

〔Effect of the invention〕

According to this invention, in a rotor with a magnet for a rotating electrical machine having magnets on the outer periphery of a rotor core fitted to a shaft, side plates made of a non-magnetic material are provided on both sides of the rotor core, and the side plates have a thickness of At least a part of the stator core is within the width of the stator core, so even if it is an open type rotating electric machine,
This prevents small pieces of iron, etc. that have entered the cooling air from adhering to the rotor, allowing the rotating electric machine to operate without failure.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a brushless DC motor having a magnetized rotor according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional magnetized rotor. 2... Stator core, 5... Rotor, 6... Shaft, 7
・・・Same figure figure

Claims (1)

[Scope of Claims] 1) In a magnet-equipped rotor of a rotating electric machine having magnets on the outer periphery of a rotor core fitted to a shaft, side plates made of a non-magnetic material are provided on both sides of the rotor core, and the side plates A magnet-equipped rotor for a rotating electrical machine, wherein at least a part of the thickness of the rotor is within the width of a stator core. 2) A magnet-equipped rotor for a rotating electrical machine according to claim 1, wherein a circumferential groove is provided on the outer peripheral surface of the side plate.