JPS5925563A - Brushless motor - Google Patents

Abstract

PURPOSE:To constitute a rotor by a simple part, and to simplify assembly work by forming the rotor by a hard magnetic material and magnetizing a position opposite to a stator coil. CONSTITUTION:A stator 2 is constituted by winding a plurality of the stator coils 4 on a stator core 3 fitted to a support cylinder 1 while coil sides are directed in the axial direction. The rotor 5 takes a cylindrical vessel shape consisting of an end plate section 5a and a circumferential wall section 5b, and the whole is formed by the hard magnetic material of large coercive force. The inner surfaces of the circumferential wall section 5b and end plate section 5a of the rotor 5 are formed in magnetizing sections 7, 8 in which different magnetic poles are formed alternately in the circumferential direction, and a section close to the lower end of the outer circumferential surface of the circumferential wall section 5b is also formed in a magnetizing section 9 in which a large number of different magnetic poles are formed alternately in the circumferential direction. A drive circuit is disposed to an annular substrate 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a brushless motor with an improved rotor structure.

[Technical background of the invention]

Conventionally, the rotor of a brushless motor has a rotating shaft fitted in the center of a cylindrical container-shaped yoke, and a permanent magnet is attached with an adhesive to the peripheral surface of the yoke that faces the stator.

[Problems with background technology]

However, with the above configuration, there is a problem in that the rotor must be constructed from a plurality of parts and requires a bonding process, resulting in poor assembly workability.

[Purpose of the invention]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a brushless motor whose rotor can be constructed from a single component and whose assembly work can be simplified as much as possible.

[Summary of the invention]

The present invention eliminates the need for the rotor to consist of two parts, a yoke and a permanent magnet, by making the rotor multi-layered from a hard magnetic material and magnetizing the portion facing the stator coil. It is characterized by its closeness.

[Embodiments of the invention]

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

1 is a hollow support cylinder, 2 is a stator fixed to this support cylinder 1, and this stator 2 has a plurality of stator coils /′L/ It consists of 4 wrapped. A portion of the stator coil 4 that protrudes above the stator core 6 is bent so that 342 sides extend in the radial direction along the upper end surface of the stator core 6 to form a radially oriented portion 4a. Reference numeral 5 denotes a rotor, which has a cylindrical container shape consisting of an end plate portion 5a and a peripheral wall portion 5b, and is entirely made of a hard magnetic material with a large coercive force. Fitted and fixed. Reference numeral 7 denotes a pair of bearings fitted into the upper and lower ends of the support portion 1, which rotatably support the rotating shaft 6 of the rotor 5.
is opposed to the upper end surface of the stator 2, and the peripheral wall portion 5b is supported so as to oppose the outer peripheral surface of the stator 2 with a gap of one violet. Different magnetic poles are formed alternately in the circumferential direction on the inner surfaces of the peripheral wall portion 5b and the end plate portion 5a of the rotor 5, forming nine magnetized portions 7, 8, and the lower end portion of the outer peripheral surface of the peripheral wall portion 5b is also formed in the circumferential direction. A large number of alternately different magnetic poles are formed on the magnetized portion 9.

Reference numeral 10 denotes an annular substrate located below the stator 2 and fitted into the support tube 1, which detects the magnetic flux of the magnetized portion 7 of the rotor 5 with a magnetic detection element (not shown) and transmits the magnetic flux to each stator coil 4. A drive circuit (not shown) that sequentially supplies power is provided. Reference numeral 11 denotes a magnetic sensor, which is attached to an annular substrate 10 facing the magnetized portion 9 on the outer circumferential side of the rotor 5, and detects the magnetic flux of the rotor 5 based on the change in magnetic flux caused by the 50 rotations of the rotor and the 90 rotations of the M magnetic portion. The rotation speed of the rotor 5 is controlled by detecting the rotation speed.

According to the above structure, since the rotor 5 can be constructed as a single component, the assembly work is simplified compared to the conventional structure in which, for example, permanent magnets had to be attached to the yoke with adhesive.
I can hit it. In addition, especially as in this embodiment, the magnetic sensor 1
1 to control the rotational speed of the rotor 5, it is sufficient to magnetize the outer circumferential surface of the rotor 5 in accordance with the magnetic sensor 11. This is even more convenient since there is no need to attach a magnet. Moreover, the stator coil is arranged opposite to the end plate portion 5a of the rotor 5.
.

By forming the radially oriented portion 4a on the fourth part 4 and also forming the magnetized part 8 on the end plate part 5a in the same way as the peripheral wall part 5b, it is possible to form not only the peripheral wall part 5'b of the fourth part 5 Since rotational torque is also generated in the end plate portion 5a, the entire inner circumferential surface of the rotor 5 can effectively contribute to the generation of rotational torque, thereby improving the overall efficiency.

〔Effect of the invention〕

As described above, the present invention has a structure in which the rotor is made of a hard lR71 material and the part of the rotor facing the stator coil is magnetized.Therefore, the rotor can be constructed from a single component, and assembly is easy. It has the effect of making it as simple as possible.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, with FIG. 1 being a longitudinal cross-sectional view of the whole, and FIG. 2 being a plan view of the stator. In the figure, 21'J is a stator, 4 is a stator coil, and 5 is a rotor. Figure 1 No. 27

Claims (1)

[Claims] 1. The rotor is configured to detect the rotational position of the rotor and sequentially energize the stator coils, characterized in that the rotor is made of a hard magnetic material, and the portion facing the stator coil is magnetized. brushless motor.