CN-121983422-A - Neodymium iron boron magnetic ring hot extrusion device and method for preparing magnetic ring

CN121983422ACN 121983422 ACN121983422 ACN 121983422ACN-121983422-A

Abstract

The invention discloses a neodymium iron boron magnetic ring hot extrusion device and a method for preparing a magnetic ring. The device comprises a female die, an upper male die assembly and a lower male die assembly, wherein the upper male die assembly comprises an upper outer male die and an upper inner male die, the upper inner male die comprises an upper inner male die body, the upper inner male die body comprises a first upper inner male die body unit and a second upper inner male die body unit which are connected, the first upper inner male die body unit is located above the second upper inner male die body unit, the outer diameter of the first upper inner male die body unit is larger than that of the second upper inner male die body unit, the second upper inner male die body unit and at least a part of the first upper inner male die body unit penetrate through an upper outer male die cavity, the lower male die assembly comprises a lower outer male die and a lower inner male die, the lower inner male die comprises a lower inner male die body, the lower inner male die body is provided with a lower inner male die cavity which is used for accommodating the second upper inner male die body unit, and at least a part of the lower inner male die body penetrates through the lower outer male die cavity. The device can prepare the thin-wall neodymium iron boron magnetic ring with large length-diameter ratio.

Inventors

SONG YANWEI
LIU GUOZHENG
FU JIANLONG
Zhu Deying
YU HAIYANG
GAO YAN
WANG DONGBO
XIE WENLIANG
WANG YU
QU KAI

Assignees

包头稀土研究院

Dates

Publication Date: 20260505
Application Date: 20260206

Claims (10)

1. The neodymium iron boron magnetic ring hot extrusion device is characterized by comprising a female die, an upper male die component and a lower male die component; The female die is provided with a female die cavity, and both ends of the female die cavity are open ends; The upper male die assembly comprises an upper outer male die and an upper inner male die; The upper outer convex die comprises an upper outer convex die body, wherein the upper outer convex die body is provided with an upper outer convex die cavity, and the outer diameter of the upper outer convex die body is matched with the diameter of the die cavity of the female die; The upper inner punch comprises an upper inner punch body, wherein the upper inner punch body comprises a first upper inner punch body unit and a second upper inner punch body unit which are connected, the first upper inner punch body unit is positioned above the second upper inner punch body unit, the outer diameter of the first upper inner punch body unit is larger than that of the second upper inner punch body unit, the outer diameter of the first upper inner punch body unit is matched with the diameter of the upper outer convex die cavity, the second upper inner punch body unit and at least a part of the first upper inner punch body unit are arranged in the upper outer convex die cavity in a penetrating manner, and the upper inner punch can move in the vertical direction relative to the upper outer convex die; The lower male die assembly comprises a lower outer male die and a lower inner male die, wherein the lower outer male die comprises a lower outer male die body, the lower outer male die body is provided with a lower outer male die cavity, the outer diameter of the lower outer male die body is matched with the diameter of the female die cavity, and the diameter of the lower outer male die cavity is basically equal to the diameter of the upper outer male die cavity; The lower inner punch comprises a lower inner punch body, the lower inner punch body is provided with a lower inner punch cavity, the outer diameter of the lower inner punch body is matched with the diameter of the lower outer punch cavity, the diameter of the lower inner punch cavity is matched with the outer diameter of the second upper inner punch body unit, the lower inner punch cavity is arranged to accommodate the second upper inner punch body unit, and at least one part of the lower inner punch body is arranged in the lower outer punch cavity in a penetrating mode.
2. The device according to claim 1, wherein the ratio of the outer diameter of the first upper inner punch body unit to the outer diameter of the second upper inner punch body unit is (1.5-5): 1.
3. The device according to claim 1, wherein the ratio of the diameter of the cavity of the die to the outer diameter of the first upper inner punch body unit is (1.1-1.5): 1.
4. The ndfeb magnet ring hot extrusion device as set forth in claim 1, wherein the ratio of the outer diameter of the second upper inner punch body unit to the diameter of the die cavity is 1 (1.5-7.5).
5. A neodymium iron boron magnetic ring hot extrusion device according to any one of claims 1 to 4, wherein the upper outer male die further comprises an upper outer male die limiting piece, and the upper outer male die limiting piece is sleeved on the periphery of the top of the upper outer male die body; The upper inner punch further comprises an upper inner punch limiting piece, and the upper inner punch limiting piece is sleeved on the periphery of the top of the upper inner punch body.
6. A neodymium iron boron magnetic ring hot extrusion device according to any one of claims 1 to 4, wherein the lower outer male die further comprises a lower outer male die limiting piece, and the lower outer male die limiting piece is sleeved on the periphery of the bottom of the lower outer male die body; The lower inner punch further comprises a lower inner punch limiting piece, and the lower inner punch limiting piece is sleeved on the periphery of the bottom of the lower inner punch body.
7. A method for preparing a magnetic ring by using the neodymium iron boron magnetic ring hot extrusion device according to any one of claims 1 to 6, which is characterized by comprising the following steps: the upper inner punch body of the assembled NdFeB magnetic ring hot extrusion device moves downwards relative to the female die, and simultaneously moves the lower inner punch body upwards relative to the female die, so that the upper inner punch body and the lower inner punch body simultaneously carry out hot extrusion on the NdFeB annular hot-pressed blank to obtain a magnetic ring; The assembled neodymium iron boron magnetic ring hot extrusion device is in a state that the upper end of a lower male die assembly is located in a female die cavity, the upper end face of a lower outer male die body is flush with the upper end face of a lower inner male die body, an NdFeB annular hot-pressing blank is located in the female die cavity, the bottom face of the NdFeB annular hot-pressing blank is respectively contacted with the upper end face of the lower outer male die body and the upper end face of the lower inner male die body, a second upper inner male die body unit is located in an inner circular hollow of the NdFeB annular hot-pressing blank, and the bottom face of the first upper inner male die body unit and the bottom face of the upper outer male die body are respectively contacted with the top face of the NdFeB annular hot-pressing blank.
8. The method according to claim 7, wherein the hot extrusion is performed in an inert gas atmosphere at a hot extrusion temperature of 700 to 900 ℃ for a hot extrusion time of 30 to 500 s.
9. The method according to claim 7, wherein the NdFeB annular hot-pressed blank is simultaneously moved upward and downward by the pressing action of the upper inner punch body and the lower inner punch body during the hot pressing, thereby pushing the upper outer punch to move upward and the lower outer punch to move downward.
10. The method of any one of claims 7-9, wherein the magnetic ring has a wall thickness of 5mm or less and a ratio of length to outer diameter of 1 or more.

Description

Neodymium iron boron magnetic ring hot extrusion device and method for preparing magnetic ring Technical Field The invention relates to a neodymium iron boron magnetic ring hot extrusion device and a method for preparing a magnetic ring. Background With the rapid development of the fields of new energy automobiles, wind power and industrial automation, the market demand of high-efficiency motors is gradually increased. The motor magnetic ring is a core component of the high-efficiency motor. The rare earth permanent magnet material has high magnetic performance and excellent stability, and becomes an important material for preparing motor magnetic rings. The hot extrusion process has the advantages of near net shape, low rare earth consumption and the like, and becomes a potential processing process. CN114334418a discloses a composite extrusion forming device for neodymium-iron-boron permanent magnet rings, which comprises a cushion block, a lower male die, a female die, an upper male die and a positioning sleeve. The female die is a hollow cylinder with two open ends and the bottom end of the female die is arranged on the cushion block. The lower male die and the upper male die are both in cylindrical structures. The lower male die is arranged at the lower part of the inner cavity of the female die, and a flange protruding towards the axis is arranged at the bottom end opening of the female die. The lower part of the lower male die is provided with a convex ring, and the lower end surface of the convex ring, the side surface of the lower main body of the lower male die and the upper surface of the cushion block form a space for accommodating the flange. Convex ring outer diameter and concave die the inner diameter of the lumen of (2) is the same. The side surface of the upper cylinder of the lower male die is spaced from the side wall of the inner cavity of the female die by a certain distance to form a positive compression molding workpiece. The upper male die is arranged at the upper part of the inner cavity of the female die through a positioning sleeve, the inner diameter of the positioning sleeve is the same as the outer diameter of the upper male die and is matched coaxially, the outer diameter of the locating sleeve is the same as the inner diameter of the inner cavity of the female die and is matched coaxially. The blank is arranged between the lower punch and the upper punch, and is extruded forward and backward simultaneously along with the downward movement of the upper punch in the thermal rheology. The forming device is not suitable for preparing the thin-wall neodymium iron boron magnetic ring with large length-diameter ratio. CN104505207a discloses a hot extrusion die, which comprises a hot extrusion core rod, a hot extrusion upper press sleeve, a hot extrusion die sleeve, a hot extrusion lower die sleeve and a hot extrusion gasket. The hot extrusion die is suitable for a forward extrusion process, the utilization rate of raw materials is low, and the wall thickness of the obtained magnetic ring is large. Disclosure of Invention Accordingly, an object of the present invention is to provide a neodymium iron boron magnetic ring hot extrusion device, which can prepare a thin-wall neodymium iron boron magnetic ring with a large length-diameter ratio. Further, the neodymium iron boron magnetic ring hot extrusion device can improve the remanence and the coercive force of the neodymium iron boron magnetic ring. Furthermore, the neodymium iron boron magnetic ring hot extrusion device can improve the maximum magnetic energy product of the neodymium iron boron magnetic ring. The invention further aims to provide a method for preparing the magnetic ring, which can prepare the thin-wall neodymium iron boron magnetic ring with large diameter ratio. Further, the method can improve the residual magnetism and the coercive force of the NdFeB magnetic ring. Furthermore, the method can improve the maximum magnetic energy product of the NdFeB magnetic ring. The above object is achieved by the following technical scheme. In one aspect, the invention provides a neodymium iron boron magnetic ring hot extrusion device, which comprises a female die, an upper male die assembly and a lower male die assembly; The female die is provided with a female die cavity, and both ends of the female die cavity are open ends; The upper male die assembly comprises an upper outer male die and an upper inner male die; The upper outer convex die comprises an upper outer convex die body, wherein the upper outer convex die body is provided with an upper outer convex die cavity, and the outer diameter of the upper outer convex die body is matched with the diameter of the die cavity of the female die; The upper inner punch comprises an upper inner punch body, wherein the upper inner punch body comprises a first upper inner punch body unit and a second upper inner punch body unit which are connected, the first upper inner punch body unit i