JP2527656Y2 - Permanent magnet rotor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention is used for an adduction type brushless motor in which a rotor is surrounded by a stator, and is a permanent magnet rotor having a segment magnet. About.

[Conventional technology]

The permanent magnet rotor used in the adduction type brushless motor is
The permanent magnet portion has a cylindrical shape, and different poles alternately appear on the outer peripheral surface thereof. In order to increase the magnetic force of the permanent magnet, a segment magnet in which a cylinder is divided for each pole is used due to restrictions on manufacturing methods such as a magnetic field forming and firing step.

A permanent magnet rotor using such segment magnets generally has a configuration shown in FIG. That is, the cylindrical yoke B made of a magnetic material is press-fitted and fixed to the rotor shaft A, and the segment magnets C1 to C4 are bonded to the outer periphery of the yoke B made of the magnetic material.

A rotor having such a configuration can handle a rotation speed of approximately several thousand rpm, but if the rotation speed is higher than that, the segment magnet cannot be held.

In recent years, brushless motors have been required to be smaller and have higher output, and the rotational speed of the rotor has been required to be higher than 10,000 rpm and even higher than 20,000 rpm. Accordingly, the temperature of the electric motor also becomes high.

Therefore, the applicant of the present application has proposed the one shown in FIG. 5 in Japanese Patent Application No. 01-71010 in order to be able to hold the segment magnet even when rotated at high speed. This one is
A plurality of arc-shaped segment magnets C1 to C4 are formed by the outer peripheral surface of a yoke B made of a magnetic material fixed to the outer periphery of the rotor shaft A and the side surfaces of the holding protrusions B1 to B4 which are provided to project radially. Disks D, D made of a nonmagnetic material having an outer diameter substantially equal to or slightly smaller than the outer diameter of the holding projections are accommodated in the formed space, and are located on both outer side surfaces of the segment magnet and the yoke in the axial direction. As a result, resin molding is performed in a state where the position of the segment magnet in the axial direction is regulated. This is one in which a molded resin layer E of a curable resin is formed. The magnetic material yoke B has a plurality of (four in this example) through holes Bd and a disk D
Also, corresponding through holes Dd are provided respectively,
The molding resin layer E described above is continuously formed in these holes.

[Problems to be solved by the invention]

The above-described permanent magnet rotor is resin-molded by a molding die as shown in FIG. In the figure, L is the lower mold, U
Is an upper mold having a gate G. The molten resin injected from the gate G is divided into a flow y1 passing through the through holes Dd and Bd provided in the disk D and the yoke B, respectively, and a flow y2 passing through the gap between the molds L and U and the segment magnet. The flow y2 also flows to the gap between the segment magnet and the holding protrusion. Finally, these are filled to form the molded resin layer E. Each segment magnet is pressed against the outer peripheral surface Ba of the yoke by the pressure of the resin at the time of molding, and is positioned at a desired position in a well-balanced manner.

By the way, the disc D is often molded using a thermoplastic resin (for example, a polyamide resin containing glass fibers) for the sake of simplification of the production. The disk D directly receives the molten resin injected from the gate G at a required molding pressure in order to form the molded resin layer E. At this time, the disc D may be deformed before the molten resin is solidified. In this case, the position of the segment magnet in the axial direction cannot be regulated, and the segment magnet is shifted in the axial direction.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a permanent magnet rotor capable of reliably controlling the axial position of a segment magnet in a resin molding process.

[Means for solving the problem]

In order to solve such a problem, the permanent magnet rotor of the present invention has a rotor shaft, a segment magnet, a yoke made of a magnetic material, a disk made of a non-magnetic material, and an axially outer surface of the disk. A gap formed between the outer peripheral surface and the segment magnet and the holding projection of the yoke, and a through-hole communicating with the yoke and the disc, formed with a molded resin layer of a thermosetting resin, In the disk and the molding resin layer, a mold projection enters a position that does not overlap with the through hole of the disk and overlaps the end surface of the segment magnet and the yoke, thereby regulating the position of the segment magnet. A plurality of insertion holes communicating from the disc to the molding resin layer are provided.

[Action]

According to the present invention, since a plurality of insertion holes for the mold projections are formed in the disk, the molding mold is provided with the segment magnets and the mold projections abutting on the end faces of the yoke. The resin molding can be performed such that the position in the axial direction is regulated. As a result, a plurality of insertion holes communicating with the insertion holes of the disc can be formed in the molding resin layer, and these insertion holes can be used as attachment portions of the balancing member.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

The permanent magnet rotor 1 includes a rotor shaft 2, a yoke 3, a plurality of (four in this embodiment) segment magnets 4a to 4d, disks 5,5 made of a nonmagnetic material, and a molding resin of a thermosetting resin. Layer 6
It is composed of

The yoke 3 is formed by laminating pieces 3a, 3a,... Formed by punching out a magnetic material such as a silicon steel plate, and has a cylindrical basic shape. This lamination thickness is substantially equal to the axial length of the segment magnets 4a to 4d described later. Further, the outer peripheral surface 3b of the yoke 3 has the same number as the segment magnets,
Holding protrusions 3c, 3c,... Having a height substantially equal to the radial thickness are radially connected. The holding projections 3c, 3c,... Become wider from near the middle of the radial height to the tip.
Therefore, the outer peripheral surface 3b and the side surfaces of the holding projections 3c, 3c,.
A substantially arc-shaped space is formed. Are through holes for molding and for forming a molded resin layer.

Each of the segment magnets 4a to 4d is an arc-shaped plate that is slightly smaller and accommodated in the space of the yoke 3. Therefore, the outer peripheral side of both ends in the circumferential direction has a shape in which a portion corresponding to the wide shape of the holding protrusion is cut off.

The disks 5, 5 made of a non-magnetic material are formed of a thermoplastic resin such as a polyamide resin containing 30% glass, and have an outer diameter substantially equal to or slightly smaller than the outer diameter of the holding projection 3c. Is formed in a substantially disk shape. Reference numerals 5d, 5d,... Are through holes for molding and for forming a molded resin layer, which are provided at positions corresponding to the through holes 3d, 3d of the yoke. 5e is a through hole through which the rotor shaft 2 is inserted. The shape of the disks 5, 5 will be described later in detail.

The molding resin layer 6 has an axially outer surface of the disks 5, 5 and an outer peripheral surface continuous therewith, a gap between the segment magnets 4a to 4d and the holding projections 3c, 3c,. , 3
, and through holes 5d, 5d,... of the disc are filled with a thermosetting resin.

Next, the shapes of the disks 5, 5 made of a non-magnetic material will be described in detail. The discs 5, 5 have a protruding portion 5g whose end face 5f projects from the axial side face of the molding resin layer 6 inwardly of a plurality of gate positions provided on the molding die. Is provided with a circumferential groove 5h. Further, an outer end surface 5i based on the circumferential groove 5h is formed so as to be deformable under pressure by a mold surface. The outer end surface 5i in the present embodiment is a disk 5,5.
In the state of the part, it is slightly protruded from the inner end face 5j, and after completion of the molding process, it is pressed and deformed by a mold so that it is substantially flush with the inner end face 5j. . That is, the distance between the outer end faces 5i, 5i is slightly larger than the dimension between the end faces 5f, 5f of the upper and lower molds.

More importantly, the discs 5,5 have their through holes 5d, 5
d,... and a plurality of (for example, 8 in this embodiment) a die protrusion enters a position overlapping the segment magnets 4a to 4d and the end surface of the yoke 3 to regulate the position of the segment magnet.
) Are formed.

5m is a thin cylindrical portion, which is coaxial with the through holes 5d, 5d,... And protrudes so as to fit into the through holes 3d, 3d,.
The thin cylindrical portion 5m is for thermally expanding by preheating performed before resin molding so that the disk 5 is firmly fixed to the yoke 3. 5n is a cut-out portion formed by cutting out the thin-walled cylindrical portion 5m, and further increases the deformation due to thermal expansion.

The manufacture of the permanent magnet rotor 1 is performed as follows. First, the yoke 3 is pressed into the rotor shaft 2. next,
The segment magnets 4a to 4d are inserted into the yoke 3, and the discs 5, 5 are pressed into the axially outer surfaces on both sides thereof so as to sandwich the same. Next, after preheating in this state, it is mounted on the upper mold U and the lower mold L. The upper and lower dies U, L are provided at positions corresponding to the insertion holes 5k, 5k,... Of the disks 5, 5 and slightly smaller than the inner diameter of the insertion holes 5k, 5k,. In addition, protrusions Ut and Lt having a length equal to the sum of the thicknesses of the molding resin layer 6 are provided. Next, the upper mold U descends and is brought into contact with the lower mold L. At this time, the outer end faces 5i, 5i of the discs 5, 5 are deformed under pressure, and the two protrusions Ut, Lt abut on the end faces of the yoke 3 and the segment magnets 4a to 4d, and the segment magnets 4a To 4d in the axial direction. And from the gate G of the upper mold U,
For example, a thermosetting resin such as an unsaturated polyester resin is injected.

In this case, the molten resin injected from the gate G causes a flow z1 passing through the through holes 5d, 3d provided in the disk 5 and the yoke 3, respectively, and a gap between the dies L, U and the segment magnets 4a to 4d. The flow Z2 is separated into a passing flow z2, and the flow Z2 also flows into a gap between the segment magnet and the holding protrusion. Finally, these are filled to form the molding resin layer 6 on the outer surface in the axial direction of the disk 5, the outer peripheral surface continuous with the outer surface, and the gap between the segment magnet and the holding projection. When the upper mold U rises, the molding resin layer 6 is formed with insertion holes 6k, 6k,... Communicating with the insertion holes 5k, 5k,.

The insertion holes 5k, 5k,.
.. can be used as attachment portions for attaching a balancing member such as putty, for example, when it is desired to improve the weight balance of the permanent magnet rotor 1.

In the present embodiment, a description has been given of the case where the raised portion 5f is formed on the disk 5, but a conventional disk-shaped one without the raised portion may be used.

[Effect of the invention]

Since the permanent magnet rotor of the present invention is configured as described above, the molding die is provided with a mold projection that abuts against the end surfaces of the segment magnet and the yoke, thereby controlling the position of the segment magnet in the axial direction. To perform resin molding,
In the resin molding process, the axial position of the segment magnet can be reliably regulated.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a view showing a disk made of the non-magnetic material, (a) is a plan view, (b) is A of (a). -A sectional view,
(C) is a bottom view, FIG. 3 is a longitudinal sectional view showing a state of being mounted on a molding die, FIG. 4 is a perspective view showing a general example, and FIG. FIG. 6 is an explanatory view for explaining a molded state of the part. 1 ... permanent magnet rotor, 2 ... rotor shaft, 3 ... yoke, 3d ... through hole, 4a to 4d ... segment magnet, 5 ...
… A disk made of non-magnetic material, 5d …… through hole, 5k …… insert hole,
6 ... molding resin layer, 6k ... insertion hole, U ... upper mold, Ut ...
Mold protrusion, L ... Lower mold, Lt ... Mold protrusion.

Claims (1)

(57) [Scope of request for utility model registration] 1. A plurality of segment magnets having an arc plate shape,
It is housed in the space formed by the outer peripheral surface of the yoke made of a magnetic material fixed to the outer periphery of the rotor shaft and the side surface of the holding projection that protrudes radially. A disk made of a non-magnetic material having an outer shape substantially equal to or slightly smaller than the outer shape of the holding protrusion is located on the outer surface in the axial direction of the disk, the outer circumferential surface continuous with the disk, and the gap between the segment magnet and the holding protrusion. A permanent magnet rotor in which a molded resin layer of a thermosetting resin is formed in a through hole communicating with the yoke and the disk, wherein the disk and the molded resin layer do not overlap the through hole of the disk. ,
And at a position overlapping the end faces of the segment magnet and the yoke,
A permanent magnet rotor in which a mold protrusion enters to regulate the position of a segment magnet and has a plurality of insertion holes communicating from a disc to a molding resin layer.