JPS5917611B2 - Permanent magnet support device for small electric motors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support device for supporting a cylindrical permanent magnet (hereinafter referred to as magnet) of a small electric motor in a housing.

Conventional support devices have a structure in which a housing and a magnet are fixed using an adhesive, or a structure in which an end surface of a magnet is pressed by a ring-shaped spring member.

Those using adhesives have many problems, such as the position of the magnetic poles shifting and varying depending on the type of work being done, and requiring drying time.

Furthermore, a ring-shaped spring member that presses the end face of the magnet requires extra parts, which increases the cost.

The conditions for fixing the magnet to the housing are that it must be easy to insert into the housing, the magnet must be positioned reliably, and the magnet must be sufficiently secured.

The present invention was made in view of the above-mentioned problems, and an object of the present invention is to provide a device that is easy to assemble, has no magnetic pole shift of the magnet, and can securely fix the magnet to the housing. It is.

An embodiment of the present invention will be described below based on the drawings.

1 is a cylindrical housing with a bottom, and a locking hole 2 and a center hole 3 are provided on the side end face, which is the bottom, and a small hole a is provided on the outer periphery near the opening to serve as the marking of the magnetic pole mark. It is set up.

4 is a cylindrical magnet, with a pair of mutually parallel planar notches 5 provided on the end side of its outer periphery, N and S magnetic poles are formed based on the notches 5; A magnetic pole mark b is provided.

Reference numeral 6 denotes an end bracket for supporting magnets and metal, which is made of synthetic resin and has a cylindrical shape.

A pair of support walls 7 are provided at the end faces of the opening to face each other.

A protrusion 8 having an acute-angled tip is integrally provided on the inner side surface of each support wall 7 so as to extend in the axial direction of the cylindrical portion.

The dimension between the pair of support walls is set as a relative dimension that is slightly smaller than the dimension l of the notch 5 of the magnet 4.

9 is a portion of the end bracket that receives the end surface of the magnet, and 10 is a locking protrusion formed on the side end surface of the end bracket.

Reference numeral 11 denotes a shaft support portion for supporting the metal 13, which is provided at the center of the end bracket, and has a shaft hole 12 formed in its tip surface.

In the above configuration, the metal 13 is inserted into the shaft support portion 11 of the end bracket 6, and the end bracket 6 is inserted into the housing 1.

At this time, the housing 1 and the end bracket 6 are prevented from rotating by fitting the locking hole 2 of the housing with the locking protrusion 10 of the bracket.

In this state, the magnet 4 is inserted into the housing 1 from the side having the notch 5, and the insertion position is determined by aligning the magnetic pole mark b and the small hole a.

Thereafter, when the magnet 4 is pressed from the end surface, the outer circumferential surface of the support wall 7 is pressed against the inner surface of the housing 1 due to the press-fitting of the notch 5 and the protrusion 8, and the friction generated by the compression causes the magnet 4 and the end bracket 6 to move toward the housing 1. It will be fixed more securely.

Since the magnet 4 is securely fixed within the housing 1, the rotor can be easily inserted and assembled.

That is, when the rotor is inserted into the hollow part of the magnet 4, a magnetic attraction force acts between the rotor and the magnet 4.

Due to this attraction force, the magnet 4 tries to pop out from the housing 1, but as described above, the magnet 4 is securely fixed inside the housing 1, so it does not pop out.

Therefore, the rotor insertion and assembly work can be easily performed.

Here, the support wall 7 of the end bracket 6 is bent by the clearance with respect to the inner diameter of the housing 1 due to the press-fitting of the magnet, but this bending is extremely small, and the fixing force that prevents the end bracket from being removed is the compressive force of the support piece. The bracket will not be damaged, and since the portion of the magnet 4 that presses the notch 5 presses against the thick portion of the remaining portion of the notch, there will be no problem with cracking.

As described above, the permanent magnet support device according to the present invention can reliably align the magnetic poles of the magnet with the magnetic poles of the housing, and is fixed by compressing the end bracket made of synthetic resin, so that the three components of the housing, end bracket, and magnet are fixed. are in close contact with each other, it is possible to achieve the desired purpose, and a remarkable effect of improving work efficiency can be expected.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a perspective view of the housing, Fig. 2 is a sectional view of the magnet, Fig. 3 is a plan view thereof, and Fig. 4 is a sectional view of the end bracket. 5
The figure is a plan view thereof, and FIG. 6 is a partial sectional view of the assembly. 1'... Housing, 4... Magnet, 5... Curved/flat notch, 6... End bracket, 7... Surface support wall.

Claims (1)

[Claims] 1 consisting of a bottomed cylindrical seven-ring ring 1, an end bracket 6 inserted into the back side of the seven-ring ring 1 and having a cylindrical part, and a cylindrical magnet 4 inserted inside the housing 1. A center hole 3 and a locking hole 2 are provided on the side end surface which is the bottom of the housing 1, and a shaft support portion 11 and a locking protrusion 10 that engage with the center hole 3 and the locking hole 2 are provided.
is formed on the side end surface of the end bracket 6 opposite to the side end surface of the housing 1, and a pair of mutually parallel planar cuts are formed on the outer periphery of the magnet 4 on the end side opposite to the end bracket 6 side. A notch 5 is formed, the end bracket 6 is made of plastic, and the open end surface of the cylindrical portion of the end bracket 6 is opposed to each notch 5 side of the magnet 4, and each notch 5 is formed in the open end surface. A pair of support walls 7 are provided which are inserted between the inner peripheral surface of the housing 1 and engage with each notch 5, and each support wall 7 has a projection 8 on a side surface facing each notch 5. The projections 8 are formed to extend in the axial direction of the cylindrical portion of the end bracket 6, and by pressing the projections against the notches 5 of the magnet 5, the support walls 1 1. A permanent magnet support device for a small electric motor, characterized in that a permanent magnet is pressed against an inner circumferential surface of a housing 1.