JPH02254952A - Motor - Google Patents

Abstract

PURPOSE:To simplify the configuration of a bearing holder, on which a preliminary pressure is applied, and facilitate the working of the bearing holder by a method wherein ball bearings are provided continuously so that the inner races and the outer races of respective ball bearings are abutted against each other while a projected part, abutting against the outer race of the ball bearing, is provided on a core retaining part. CONSTITUTION:A projected part 17, projected toward the inside of a bearing holder 2 provided through insert molding, it provided on a core retaining part 3 and is positioned so as to be abutted against the outer race 8a of a bali bearing 8. The center A of the stator core of a stator 4 and the center B of the magnet or a rotor 12 are arranged so as to be deviated from a magnetic center and the bearing holder 2 is formed so as to have a straight tubular shape while two sets of ball bearings 8, 8 are provided continuously in the bearing holder 2 so that the inner races 8b and the outer races 3a of the bearings 8, 8 are abutted against each other and a shaft retaining member 13 is abutted against the inner race 8b of said ball bearing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an outer rotor type electric motor used in a blower or the like.

[Conventional technology]

FIG. 3 is a sectional view showing a conventional electric motor disclosed in, for example, Japanese Utility Model Application Publication No. 59-109247.
) is a frame such as a casing made of synthetic resin with ventilation passages, and the core holding part (2) is integrally formed by insert molding in the center.
3) is provided. (A) is a stator that is fixed to the circumferential side of this bearing holder and has a winding (7) wound around the stator core (F) via an insulating cover (6), and (B) is the above-mentioned bearing holder (2). A ball bearing (9) is fitted with a predetermined interval at both ends of the bearing holder (2), and (9) is a convex portion formed on the bearing holder (2) so as to abut the ball bearing and press the outer ring (8a) upward. a preload spring provided between (11)
, is a rotating shaft that is fitted and rotatably supported by the ball bearing (5), and (12) is a shaft holding member (13) that abuts the inner ring (8b) of the ball bearing (to) on this rotating shaft. ) with a magnet (14) facing the circumferential side of the stator (a), a rotor yoke (15) provided with this magnet, and a rotor provided integrally on the outer periphery of this rotor yoke. It is formed from a blade (16).

A conventional electric motor is constructed as described above, and when the winding ■ is energized, the rotor (A) is centered around the rotating shaft (11) due to the magnetic action between the stator (A) and the magnet (!4). rotate to
Air is blown by vanes (16).

[Problem to be solved by the invention]

In the conventional electric motor as described above, since this is done by the preload spring (9) of the ball bearing (to), it is necessary to provide a convex portion Ql on the bearing holder (2) to receive the preload spring (9), which reduces the machining time. Not only does it cost more and is expensive, but the inner ring (8b) of each ball bearing
There was a problem that the preload applied to the outer ring (8a) was in the opposite direction as shown by the arrow in the figure, and the effect of the preload was poor.

This invention was made to solve the problem,
The object of the present invention is to obtain an electric motor that applies preload to a ball bearing in the same direction, is easy to process, and can be manufactured at low cost.

[Means to solve the problem]

The electric motor according to the present invention includes a frame provided with a core holding part, a bearing holder provided in the core holding part, and a winding fixed to the circumferential side of the bearing holder and wound around a stator core via an insulating cover. a stator mounted on the bearing holder, a plurality of ball bearings provided in the bearing holder, a rotating shaft that fits into the ball bearings and is rotatably supported, and a shaft that abuts the inner ring of the ball bearing on the rotating shaft. a rotor having magnets provided via a holding member and facing each other on the circumferential side of the stator with their magnetic centers shifted in the direction of the rotation axis;
The ball bearings are arranged in series so that their respective inner and outer rings abut, and the core holding portion is provided with a protrusion that abuts the outer ring of the ball bearing.

Further, the stator core and the bearing holder are inserted, and the core holding part and the insulating cover are integrally molded with synthetic resin and fixed to the frame.

[Effect]

In this invention, since the magnetic centers of the stator and the magnet are shifted, it is possible to apply preload via the shaft holding member that contacts the inner ring of the ball bearing, and the ball bearings are connected in series to hold the core. Since the bearing holder is provided with a protrusion on which the ball bearing comes into contact, the shape of the bearing holder is simple, and the protrusion is used for positioning, which facilitates machining.

Further, since the stator core and the bearing holder are inserted, the core holding part and the insulating cover are integrally molded with synthetic resin, and fixed to the frame, there is no need to cover the stator core with the insulating cover other than the above.

〔Example〕

FIG. 1 is a sectional view showing an embodiment of the present invention, in which (1) to 8 and (11) to (16) indicate the same or equivalent parts as in the above conventional example, and (17) indicates a core holding portion. θ)
This is a protrusion that protrudes from the inside of the bearing holder (2), which is provided by insert molding in the ball bearing (2), and it comes into contact with the outer ring (8a) of the ball bearing (2) for positioning.

Stator core center of stator (2) <A) and rotor, (1
The center of the magnet (B) in 2) is arranged with the magnetic center shifted as shown in the figure, and the bearing holder (2) is formed in a straight cylinder shape. (
8b) and the outer ring (8a) are arranged so as to be in contact with each other, and the shaft holding member (13) is in contact with the inner ring (8b) of the ball bearing.

In the electric motor configured as above, the winding (7)
When energized, the rotor (A) rotates around the rotating shaft (11) due to the magnetic action of the stator (2) and the magnet (14), and the blades (16) blow air. The rotor (A) tries to move due to the reaction caused by this air blowing, but since the magnetic centers of the stator (A) and the magnets (14) are shifted, a preload is applied and a force against the movement of the rotor (12) is applied. can withstand. Furthermore, since the ball bearings are connected in series, the preload direction of the outer ring (8a) and the inner ring (8b) are the same, resulting in a good preload effect, and the bearing holder (2) is also a straight cylinder. It is only necessary to form it into a shape, and its processing becomes easy.

In addition, in the above embodiment, the frame (1) and the core holding part (3
) are integrally molded from synthetic resin, but as shown in Figure 2, the stator core (51) and bearing holder (2) are insert-molded when molding the insulating cover (6) made of synthetic resin with electrical insulation properties. By forming a core holding part L31 and fixing this core holding part (31) to the frame (1) by means such as welding, an insulating cover (6
), which has the effect of improving workability.

〔Effect of the invention〕

As explained above, the present invention includes a frame provided with a core holding part, a bearing holder provided in the core holding part,
A stator fixed to the circumferential side of this bearing holder and having a winding wound around the stator core through an insulating cover, a plurality of ball bearings provided in the bearing holder, and a stator that is fitted to the ball bearings and rotates. a rotating shaft that is supported by the rotary shaft; and a magnet that is provided on the rotating shaft via a shaft holding member that contacts the inner ring of the ball bearing and that faces the stator with its magnetic center shifted in the direction of the rotating shaft. The ball bearings are arranged in series so that the inner and outer rings of the ball bearings are in contact with each other, and the core holding portion is provided with a protrusion that comes into contact with the outer ring of the ball bearing. The shape of the bearing holder, which applies preload without using a preload spring, is simple, easy to process, and can be manufactured at low cost.

In addition, by inserting the stator core and bearing holder, and integrally molding the core holding part and insulating cover with synthetic resin and fixing them to the frame, there is no need to cover the stator core with an insulating cover, making it cheaper. It has the effect of becoming a thing.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, FIG. 2 is a sectional view showing another embodiment of the invention, and FIG. 3 is a sectional view showing a conventional electric motor. In addition, the same reference numerals in each figure indicate the same or equivalent parts.
1) is the frame, ■ is the bearing holder, (3) is the core holding part, (2) is the stator, ((5) is the stator core, (6) is the insulation cover, (7) is the winding, (to ) is a ball bearing,
(8a) is the outer ring, (8b) is the inner ring, (11) is the rotating shaft,
(12) is a rotor, (13) is a shaft holding member, (14) is a magnet, and (17) is a protrusion.

Claims (2)

[Claims] (1) A frame provided with a core holding part, a bearing holder provided in the core holding part, and a stator fixed to the circumferential side of the bearing holder and having a winding wound around the stator core via an insulating cover. and a plurality of ball bearings provided in the bearing holder, a rotary shaft that fits into the ball bearings and is rotatably supported, and a shaft holding member that abuts the inner ring of the ball bearing on the rotary shaft. a rotor provided on the circumferential side of the stator and having magnets facing each other with their magnetic centers shifted in the direction of the rotation axis, and the ball bearings are arranged in series so that the inner and outer rings of the rotor are in contact with each other, An electric motor, wherein the core holding portion is provided with a protruding portion that comes into contact with an outer ring of the ball bearing. (2) The electric motor according to claim 1, wherein the stator core and the bearing holder are inserted, and the core holding portion and the insulating cover are integrally molded from synthetic resin and fixed to the frame.