CN111983537A

CN111983537A - Magnetic resonance magnet structure with separated magnetic conduction and bearing functions

Info

Publication number: CN111983537A
Application number: CN202010838187.8A
Authority: CN
Inventors: 吴嘉敏; 徐征; 何为; 贺玉成
Original assignee: Shenzhen Academy of Aerospace Technology
Current assignee: He Wei; He Yucheng; Liao Yingxiang; Wu Jiamin; Xu Zheng; Shenzhen Academy of Aerospace Technology
Priority date: 2020-08-19
Filing date: 2020-08-19
Publication date: 2020-11-24
Anticipated expiration: 2040-08-19
Also published as: CN111983537B

Abstract

The invention belongs to the technical field of nuclear magnetic resonance, and relates to a magnetic resonance magnet structure with separated magnetic conduction and bearing functions, which comprises a bearing structure and a magnetic circuit structure arranged in the bearing structure, wherein the magnetic circuit structure comprises magnetic conduction layers fixedly arranged on the upper side, the lower side, the left side and the right side of the bearing structure, disc-shaped fixing plates are fixedly arranged on the magnetic conduction layers on the upper side and the lower side, a plurality of magnet blocks are discretely distributed on the fixing plates, and high magnetic conduction shimming materials are coated on the magnet blocks.

Description

Magnetic resonance magnet structure with separated magnetic conduction and bearing functions

Technical Field

The invention belongs to the technical field of nuclear magnetic resonance, relates to a magnetic resonance magnet structure with separated magnetic conduction and bearing functions, and particularly relates to a novel lightweight magnetic resonance magnet structure with separated magnetic conduction and bearing functions.

Background

At present, the demand of each department of a hospital in China on a magnetic resonance system is gradually increased, and the quality of the conventional permanent magnet magnetic resonance system is too large, so that the demand of using any department of any floor of the hospital can not be met, and the demand of monitoring images at the bedside can not be met. In order to meet the requirement that a magnetic resonance system enters general wards of various departments, the problem of light weight of a main magnet needs to be solved firstly. The existing nuclear magnetic resonance apparatus adopts a design idea of integrating a magnetic conduction structure and a bearing structure, the periphery of the nuclear magnetic resonance apparatus usually adopts A3 steel as a magnetic conduction loop (a high magnetic conduction material for guiding the circulation of a magnetic field, also called as an iron yoke), and the iron yoke plays two roles of magnetic conduction and weight support at the same time, so that the weight of the iron yoke is very large, the light weight of the apparatus is limited, and the magnetic conduction and the bearing cannot be well coordinated in two contradictions. Therefore, the optimization of the magnetic conduction loop is carried out, and the optimization has important significance on the light weight design of equipment. And the existing magnetic poles are mostly designed in a flat plate type, the structure is simple, the adjustable parameters are few, and the efficiency of generating the magnetic field is low.

Disclosure of Invention

In view of the above, the present invention provides a magnetic resonance magnet structure with separated magnetic conduction and load bearing functions, which can solve the problem that the two contradictions of magnetic conduction and load bearing in the magnetic resonance magnet structure in the prior art cannot be well coordinated, and can ensure that the magnetic conduction and the supporting function of the yoke are not affected while the weight of the magnet is greatly reduced.

In order to achieve the above purpose, the present invention provides a magnetic resonance magnet structure with separated magnetic conduction and bearing functions, which comprises a bearing structure and a magnetic circuit structure arranged inside the bearing structure, wherein the magnetic circuit structure comprises magnetic conduction layers fixedly arranged on the upper, lower, left and right sides of the bearing structure, disc-shaped fixing plates are fixedly arranged on the magnetic conduction layers on the upper and lower opposite sides, a plurality of magnet blocks are discretely distributed on the fixing plates, and the magnet blocks are coated with high magnetic conduction shimming materials.

The beneficial effect of this basic scheme lies in: the high-permeability shimming material above the magnet block can correct the deviation problem of the magnetizing direction of the magnet block and improve the magnetic field distribution of the whole magnet block.

Furthermore, one side of the magnet block, which is far away from the corresponding magnetic conduction layer, is fixedly provided with a non-magnetic conduction cover plate, and the non-magnetic conduction cover plate is provided with shimming pieces. Has the advantages that: the shims can further improve the uniformity of the magnetic field throughout the target region of the magnet block.

Further, the magnet block shape is one or more of a fan shape, a square shape, and a trapezoid shape. Has the advantages that: sector, square and trapezoidal magnet blocks are able to provide the target magnetic field with maximum efficiency.

Furthermore, the magnetic circuit structure and the bearing structure are fastened by adopting screws and structural adhesive.

Furthermore, the bearing structure comprises two bearing plates which are arranged in an up-down symmetrical mode and a supporting plate arranged between the two bearing plates.

Furthermore, a hole site for conveniently clamping the magnet block is arranged on the fixing plate. Has the advantages that: the holes in the fixing plate facilitate a secure mounting of the magnet block.

Furthermore, the magnetic conduction layer is an iron yoke plate made of high magnetic conduction materials.

Further, the outer side of the bearing plate is arc-shaped.

Furthermore, the bearing structure formed by the bearing plate and the supporting plate is cuboid.

Furthermore, the high permeability shimming material is one of electrician pure iron, permalloy and silicon steel, but is not limited to the materials.

The invention has the beneficial effects that:

1. the invention discloses a magnetic resonance magnet structure with separated magnetic conduction and load bearing functions, wherein a magnetic circuit structure is separated from a load bearing structure, an inner layer magnetic conduction structure (an iron yoke) provides a magnetic loop, and a magnetic conduction metal (alloy) material such as electrician pure iron, carbon structural steel, amorphous alloy and the like is adopted; the outer layer load-bearing structure is mainly composed of high-strength and light-weight materials, such as titanium alloy, magnesium aluminum alloy, carbon fiber and the like. The bearing structure uses a material with low density but high yield strength, and the magnetic circuit structure uses a material with high magnetic conductivity, so that the stability of the structure is ensured while a sufficient magnetic circuit is provided, and the purpose of reducing the weight of the whole structure is realized.

2. The magnetic resonance magnet structure with separated magnetic conduction and bearing functions disclosed by the invention is designed by adopting the separated magnet blocks, the height and size of each magnet block can be freely adjusted, the shape of the magnet block is not limited, and the shape of the magnet block can be a sector, a square, a trapezoid and the like according to actual optimization requirements, so that the aim of providing a target magnetic field with the maximum efficiency is fulfilled. The high-permeability shimming material is added above the magnet block, so that the magnetizing direction deviation can be corrected to a great extent, and the uniformity of the magnetic field distribution is improved.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.

Drawings

For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic view of a magnetic resonance magnet structure with separated magnetic conductive and load bearing functions in embodiment 1 of the present invention;

fig. 2 is a schematic view of a structure of a magnetic resonance magnet with separated magnetic conductive and load bearing functions in embodiment 2 of the present invention;

FIG. 3 is a schematic cross-sectional view of a magnetically permeable and load bearing functionally decoupled MR magnet configuration according to the present invention;

FIG. 4 is a schematic view of the distribution of the magnet blocks on the fixed plate in the magnetically conductive and load bearing functionally decoupled MR magnet configuration of the present invention;

FIG. 5 is a diagram of the installation of the magnet blocks on the magnetically permeable layer in the magnetically permeable and load bearing functionally decoupled MR magnet structure of the present invention;

FIG. 6 is a magnetic field distribution diagram of a magnet block in a target region in example 2 of the present invention;

FIG. 7 is a magnetic field distribution diagram of a magnet block without highly magnetically permeable shimming material mounted thereon in a magnetically permeable and load bearing functionally decoupled magnetic resonance magnet structure of the present invention;

fig. 8 is a magnetic field distribution diagram of highly magnetically conductive shimming materials mounted on magnet blocks in a magnetic resonance magnet structure with separated magnetic conduction and load bearing functions.

Reference numerals: the magnetic field generator comprises a bearing plate 1, a supporting plate 2, a magnetic conduction layer 3, a fixing plate 4, a magnet block 5, a cover plate 6, a shim 7 and high-magnetic-conduction shim materials 8.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.

Wherein the showings are for the purpose of illustrating the invention only and not for the purpose of limiting the same, and in which there is shown by way of illustration only and not in the drawings in which there is no intention to limit the invention thereto; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not an indication or suggestion that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes, and are not to be construed as limiting the present invention, and the specific meaning of the terms may be understood by those skilled in the art according to specific situations.

Example 1

The magnetic resonance magnet structure with separated magnetic conduction and bearing functions as shown in fig. 1 and 3-5 comprises a double-upright-column type bearing structure and a magnetic circuit structure arranged in the bearing structure, wherein the bearing structure comprises two bearing plates which are arranged in an up-down symmetrical manner and a supporting plate 2 arranged between the two bearing plates. The outer side of the bearing plate is arc-shaped, the supporting plates 2 are of a columnar structure, and the two supporting plates 2 form an open shape. The load bearing structure uses a high yield strength material such as titanium alloy, magnesium aluminum alloy, carbon fiber, etc., which has a low density but a high yield strength. The magnetic circuit structure adopts magnetic conductive metal materials with high magnetic conductivity, such as electrician pure iron, carbon structural steel, amorphous alloy and the like, and aims to provide enough magnetic circuits, ensure the structural stability and reduce the weight of the whole structure. This patent magnetic circuit structure adopts the iron yoke board of high magnetic material preparation, and magnetic circuit structure and load-carrying members adopt fastening such as screw, structural adhesive.

The magnetic circuit structure comprises magnetic conduction layers 3 which are fixedly arranged on the upper side, the lower side, the left side and the right side of the bearing structure, disc-shaped fixing plates 4 are fixedly arranged on the magnetic conduction layers 3 on the upper side and the lower side, a plurality of hole sites convenient for clamping magnet blocks 5 are arranged on the fixing plates 4, the magnet blocks 5 are discretely distributed on the fixing plates 4, the height and the size of each magnet block 5 can be freely adjusted, the shape of each magnet block 5 is unlimited, the shape can be one or more of fan-shaped, square and trapezoid according to actual optimization requirements, and the purpose of providing a target magnetic field at the maximum efficiency is achieved. The discretely distributed magnet blocks 5 are restrained and fixed by the fixing plates 4 made of non-magnetic conductive materials, and the magnet blocks 5 are fixed on the upper and lower magnetic conductive layers 3 (yoke plates) in a dual mode of an adhesive and the fixing plates 4. The magnet block 5 is coated with high magnetic conduction shimming materials 8, and the high magnetic conduction shimming materials 8 are one of electrician pure iron, permalloy and silicon steel. The highly magnetic conductive shimming material 8 above the magnet blocks 5 can correct the problem of the deviation of the magnetizing direction of the magnet blocks 5 and improve the magnetic field distribution of the whole magnet blocks 5. In order to generate a uniform magnetic field in the target region, it is proposed to optimize parameters such as the distribution positions of the magnet blocks 5, the heights of the magnet blocks 5, the sizes of the magnet blocks 5, and the heights and sizes of the shim pieces 7 using an optimization algorithm (an intelligent optimization algorithm such as a genetic algorithm, a particle swarm algorithm, or the like). One side of the magnet block 5, which is far away from the corresponding magnetic conduction layer 3, is fixedly provided with a circular non-magnetic conduction cover plate 6 corresponding to the fixing plate 4, the non-magnetic conduction cover plates 6 are clamped on the magnetic conduction layers 3 on the left side and the right side, and shimming pieces 7 are arranged on the non-magnetic conduction cover plates 6, so that the uniformity of a magnetic field in a target area of the whole magnet block 5 is further improved. The magnetic field profile of the magnet block in the target zone is shown in FIG. 8.

Example 2

As shown in fig. 2, the magnetic resonance magnet structure with separated magnetic permeability and load bearing function, embodiment 2 is different from embodiment 1 in that the shape of the load bearing structure is similar to a mouth shape, the load bearing structure formed by the load bearing plate and the support plate 2 is in a rectangular parallelepiped shape, and the magnetic field distribution diagram of the magnet block in the target area is shown in fig. 6.

Comparative example

The comparative example differs from example 1 in that no highly magnetically permeable shim material was mounted on the magnet blocks 5 and the field profile of the magnet blocks in the target zone is shown in figure 7.

Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.

Claims

1. The utility model provides a magnetic resonance magnet structure of magnetic conduction and separation of bearing function, its characterized in that includes bearing structure and sets up the magnetic circuit structure in bearing structure inside, and magnetic circuit structure includes the magnetic conduction layer of four sides about fixed mounting is about bearing structure, and fixed mounting has discoid fixed plate on the magnetic conduction layer of upper and lower relative both sides, and discrete distribution has a plurality of magnet blocks on the fixed plate, and the cladding has high magnetic conduction shimming material on the magnet block.

2. A magnetic resonance magnet structure as claimed in claim 1, wherein a non-magnetically conductive cover plate is fixedly mounted on a side of the magnet block remote from the corresponding magnetically conductive layer, and shimming pieces are mounted on the non-magnetically conductive cover plate.

3. A magnetic resonance magnet structure as claimed in claim 2, wherein the magnet blocks are one or more of fan, square and trapezoidal in shape.

4. A magnetic resonance magnet structure as claimed in claim 2, wherein the magnetic circuit structure is fastened to the load bearing structure by screws or structural glue.

5. A magnetic resonance magnet structure as claimed in claim 1, characterized in that the load bearing structure comprises two load bearing plates arranged symmetrically above and below and a support plate arranged between the two load bearing plates.

6. The mr magnet structure of claim 1 wherein said mounting plate defines apertures for receiving said magnet blocks.

7. A magnetic resonance magnet structure as claimed in claim 1, wherein the magnetically permeable layer is a yoke plate made of a highly magnetically permeable material.

8. The mr magnet structure of claim 1 wherein said bearing plate outer side is arcuate.

9. A magnetic resonance magnet structure as claimed in claim 1, wherein the load bearing structure formed by the load bearing plate and the support plate is rectangular parallelepiped.

10. A magnetic resonance magnet structure as claimed in claim 1, wherein the highly magnetically permeable shimming material is one of electrically pure iron, permalloy, silicon steel.