WO2020043049A1

WO2020043049A1 - Composite type permanent magnet of synchronous permanent magnet motor rotor

Info

Publication number: WO2020043049A1
Application number: PCT/CN2019/102518
Authority: WO
Inventors: 胡思宁; 熊伟华; 吴立华; 董继勇
Original assignee: 南京磁谷科技有限公司
Priority date: 2018-08-30
Filing date: 2019-08-26
Publication date: 2020-03-05
Also published as: CN108847733A

Abstract

A composite type permanent magnet of a synchronous permanent magnet motor rotor, comprising permanent magnets (1), a permanent magnet support (2), and a permanent magnet sheath (3). The two permanent magnets (1) are symmetrically fixedly connected on an outer wall of the permanent magnet support (2), the permanent magnets (1) and the permanent magnet support (2) form a cylindrical composite permanent magnet unit with a smooth outer wall surface. The permanent magnet sheath (3) is sheathed on the composite permanent magnet unit, and the permanent magnet sheath (3) and the composite permanent magnet unit are in interference fit. The permanent magnet support (2) is made of low-carbon steel. The composite type permanent magnet reduces consumption of permanent magnet materials, greatly reduces cost and can directly replace the original cylindrical permanent magnet parts, and thus a production line does not need to be changed. High-strength alloy steel can be replaced by austenitic stainless steel, thus the material cost of the permanent magnet sheath is reduced.

Description

Composite permanent magnet of synchronous permanent magnet motor rotor

Technical field:

The invention relates to a composite permanent magnet of a synchronous permanent magnet motor rotor.

Background technique:

Magnetic levitation motors are much smaller than ordinary motors due to their high speed. Therefore, some medium-powered magnetic levitation permanent magnet motors use simple integral permanent magnets. There are two advantages to this: first, the rotor has a simple structure and is easy to manufacture; second, the rotor mandrel can be made of non-magnetically permeable material, so as to avoid the magnetic interference of the rotor permanent magnets from working with the magnetic bearings.

But the disadvantages of the overall permanent magnet are also obvious:

1) The amount of permanent magnet material is large, the cost is high, and the resource is wasted.

2) The permanent magnet sheath has a large stress, and an expensive high-strength alloy material must be used.

Since the working temperature of the rotor can reach above 100 ° C, and the thermal expansion coefficient of the permanent magnet is close to 0, and the thermal expansion coefficient of the sheath is 12-16, the sheath and the permanent magnet tend to loosen during operation.

In order to keep the interference connection of the permanent magnet and the sheath reliable, and to offset the looseness caused by the gap of thermal expansion, the stress of the sheath is very large (in some cases, it can reach 700-1000MPa), so that expensive high-strength alloy materials must be used.

Summary of the invention:

The present invention is to provide a composite permanent magnet of a rotor of a synchronous permanent magnet motor in order to solve the problems existing in the prior art.

The technical scheme adopted by the present invention is: a composite permanent magnet of a synchronous permanent magnet motor rotor, which includes a permanent magnet, a permanent magnet bracket, and a permanent magnet sheath, and the two permanent magnets are symmetrically and fixedly connected to the outer wall of the permanent magnet bracket. And the permanent magnet and the permanent magnet bracket form a cylindrical composite permanent magnet unit with a smooth outer wall surface, the permanent magnet sheath is set on the composite permanent magnet unit, and the interference fit between the permanent magnet sheath and the composite permanent magnet unit ;

The permanent magnet bracket is made of low carbon steel.

Further, the permanent magnet bracket includes a cylindrical body, and two rectangular mounting grooves are symmetrically provided on the outer circumferential wall of the body, and the two mounting grooves are arranged along the axis direction of the body.

Further, the permanent magnet is bonded in the installation groove by epoxy glue, and an arc surface is provided on the permanent magnet. After the permanent magnet is fixed in the installation groove, the arc surface of the permanent magnet and the outer wall surface of the body jointly form a smooth surface. Cylindrical outer wall surface.

Further, the permanent magnet sheath is made of austenitic stainless steel material.

The invention has the following beneficial effects:

1) Save the consumption of permanent magnet materials and greatly reduce the cost:

Because a portion of the permanent magnet material is replaced by a low-carbon steel permanent magnet bracket, the consumption of the permanent magnet material can be reduced by about 50%, and the cost of the permanent magnet can be reduced by nearly 50%.

2) It can directly replace the original cylindrical permanent magnet parts without changing the production line:

The overall shape of the composite permanent magnet is still cylindrical, which is consistent with the original solid permanent magnet. Therefore, it is possible to replace the solid permanent magnet with a composite permanent magnet part directly on the original production line without having to adjust and change the production line.

3) Austenitic stainless steel can be used to replace high-strength alloy steel to reduce the cost of permanent magnet sheath materials:

Since the low-carbon steel has the same thermal expansion rate as the sheath, it will not be loosened from the permanent magnet sheath due to thermal expansion during work, so the interference of the sheath can be greatly reduced and the sheath stress can be reduced (as low as 200-250Mpa) Therefore, the low-cost austenitic stainless steel material is used to manufacture the permanent magnet sheath. Only this change can reduce the manufacturing cost of the permanent magnet sheath by more than 70%.

Brief description of the drawings:

FIG. 1 is a structural diagram of the present invention.

FIG. 2 is a structural diagram of a composite permanent magnet unit composed of a permanent magnet and a permanent magnet bracket in the present invention.

Figure 3 is an exploded view of the present invention.

detailed description:

The invention is further described below with reference to the drawings.

As shown in Figures 1 to 3, the present invention discloses a composite permanent magnet of a synchronous permanent magnet motor rotor, which includes a permanent magnet 1, a permanent magnet support 2, and a permanent magnet sheath 3. The two permanent magnets 1 are symmetrically fixedly connected to the permanent magnet support. 2 on the outer wall, and the permanent magnet 1 and the permanent magnet bracket 2 form a cylindrical composite permanent magnet unit with a smooth outer wall surface, the permanent magnet sheath 3 is set on the composite permanent magnet unit, and the permanent magnet sheath 3 and the composite Interference fit between permanent magnet units.

The permanent magnet bracket 2 in the present invention includes a cylindrical body 21, and two rectangular mounting grooves 22 are symmetrically provided on an outer circumferential wall of the body 21, and the two mounting grooves 22 are arranged along the axis direction of the body 21.

The permanent magnet 1 is bonded in the mounting groove 22 by epoxy glue, and an arc surface is provided on the permanent magnet 1. After the permanent magnet 1 is fixed in the mounting groove 22, the arc surface of the permanent magnet 1 and the outer wall surface of the body 21 are common. Forms a smooth cylindrical outer wall surface.

The permanent magnet bracket 2 in the present invention is made of low carbon steel, and the permanent magnet sheath 3 is made of austenitic stainless steel material.

The "I" -shaped permanent magnet bracket 2 made of low-carbon steel fixes two "tile-shaped" permanent magnets 1 to achieve the same electromagnetic characteristics as the surface-mounted structure.

The permanent magnet 1 and the permanent magnet bracket 2 are bonded and assembled with epoxy glue. After the permanent magnet 1 and the permanent magnet bracket 2 are assembled, the shape of the entire composite permanent magnet unit is cylindrical. After the composite permanent magnet unit is assembled, it is subjected to cylindrical grinding as a whole so as to be assembled with the permanent magnet sheath 3.

The above is only a preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, several improvements can be made without departing from the principles of the present invention, and these improvements should also be considered as the invention. protected range.

Claims

A composite permanent magnet of a synchronous permanent magnet motor rotor, which is characterized by comprising a permanent magnet (1), a permanent magnet bracket (2) and a permanent magnet sheath (3), and the two permanent magnets (1) are symmetrically fixedly connected. On the outer wall of the permanent magnet bracket (2), the permanent magnet (1) and the permanent magnet bracket (2) form a cylindrical composite permanent magnet unit with a smooth outer wall surface, and the permanent magnet sheath (3) is sleeved on the composite permanent magnet. Interference fit between the permanent magnet sheath (3) and the composite permanent magnet unit on the magnetic unit;

The permanent magnet bracket (2) is made of low carbon steel.
The composite permanent magnet of a synchronous permanent magnet motor rotor according to claim 1, characterized in that the permanent magnet bracket (2) comprises a cylindrical body (21), which is symmetrical on the outer circumferential wall of the body (21) Two rectangular mounting grooves (22) are provided, and the two mounting grooves (22) are arranged along the axial direction of the body (21).
The composite permanent magnet of a synchronous permanent magnet motor rotor according to claim 2, characterized in that the permanent magnet (1) is bonded in the mounting groove (22) by epoxy glue on the permanent magnet (1). An arc surface is provided, and after the permanent magnet (1) is fixed to the mounting groove (22), the arc surface of the permanent magnet (1) and the outer wall surface of the body (21) form a smooth cylindrical outer wall surface together.
The composite permanent magnet of a synchronous permanent magnet motor rotor according to claim 1, characterized in that the permanent magnet sheath (3) is made of austenitic stainless steel material.