CN111416496A - Moving-coil electromagnetic linear actuator based on combined Halbach array - Google Patents

Moving-coil electromagnetic linear actuator based on combined Halbach array Download PDF

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CN111416496A
CN111416496A CN202010338750.5A CN202010338750A CN111416496A CN 111416496 A CN111416496 A CN 111416496A CN 202010338750 A CN202010338750 A CN 202010338750A CN 111416496 A CN111416496 A CN 111416496A
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halbach array
magnetic
coil
permanent magnets
moving
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CN111416496B (en
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谭草
葛文庆
李波
姜晓涵
王赓
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Shandong University of Technology
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Shandong University of Technology
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K41/00Propulsion systems in which a rigid body is moved along a path due to dynamo-electric interaction between the body and a magnetic field travelling along the path
    • H02K41/02Linear motors; Sectional motors
    • H02K41/03Synchronous motors; Motors moving step by step; Reluctance motors
    • H02K41/031Synchronous motors; Motors moving step by step; Reluctance motors of the permanent magnet type

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  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Electromagnetism (AREA)
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  • Reciprocating, Oscillating Or Vibrating Motors (AREA)

Abstract

The invention discloses a moving-coil electromagnetic linear actuator based on a composite Halbach array, which comprises: the electromagnetic field sensor comprises an end cover, a coil framework, a magnet yoke, an electromagnetic coil group, a main Halbach array layer, an auxiliary Halbach array layer, an air gap, a magnetic isolation shaft and a resonant spring; the combined Halbach array comprises a main Halbach array layer and an auxiliary Halbach array layer, wherein the main array layer is formed by alternately and closely arranging axial magnetizing permanent magnets and radial magnetizing permanent magnets, and the auxiliary array layer alternately and closely arranged with the axial magnetizing permanent magnets and the magnetic conduction blocks among the magnets is combined and fixed on a magnetism isolating shaft to serve as a magnetic source; the electromagnetic coil group is embedded on the coil framework, acts as the rotor and can do reciprocating linear motion in the air gap, and the main Halbach array layer is positioned between the rotor and the auxiliary Halbach array layer; the magnetic yoke and the magnetic source are fixed and used as a stator, and the gap between the magnetic yoke and the magnetic source is an air gap. The moving-coil electromagnetic linear actuator adopts the composite Halbach array, improves the self-shielding capability of a magnetic circuit and the power density of the actuator, and has good control characteristic and stability.

Description

Moving-coil electromagnetic linear actuator based on combined Halbach array
Technical Field
The invention relates to the technical field of motors, in particular to a moving-coil type electromagnetic linear actuator based on a combined Halbach array.
Background
The electromagnetic linear actuator is used as a driving element, can directly convert input electric energy into mechanical energy of linear motion, and meets the application occasions of linear motion, large driving force, stable feeding and the like. The moving-coil electromagnetic linear actuator has the advantages of high frequency response, high precision and the like, so that the moving-coil electromagnetic linear actuator is widely concerned. In recent years, under the new requirements and the promotion of new materials and new technologies, especially the wide application of sintered neodymium iron boron and other permanent magnetic materials, the electromagnetic linear actuator has been developed more greatly.
In the application of the electromagnetic linear actuator, the contradiction between the driving requirement and the limited installation space provides a test for the compact structure and the reliability of the actuator, the maximum output value obtained by using a smaller volume becomes the primary target of the electromagnetic linear actuator at the present stage, the larger volume power density is provided, the coordination and the stability of the whole electric driving linear system are ensured, and the mapping relation between the size space and the output characteristic can be effectively improved. Although the common Halbach array can effectively enhance the magnetic flux density of one side of the permanent magnet, weaken the magnetic flux density of the other side, and improve the air gap magnetic density to a certain extent, a large amount of magnetic leakage still exists, and the power density of the electromagnetic actuator still needs to be further improved. Meanwhile, the electromagnetic actuator based on the common Halbach array needs an extra magnetic yoke to fix a permanent magnetic material, so that the assembly difficulty of the actuator is improved.
According to the moving-coil type electromagnetic linear actuator based on the composite Halbach array, the auxiliary Halbach array layer is adopted to reduce the magnetic leakage of the main Halbach array layer, the air gap flux density is further enhanced, the volume power density of the electromagnetic linear actuator is improved, the power transmission efficiency of the whole electromechanical system can be effectively improved, and the work coordination and the application universality of the linear actuator are ensured.
Disclosure of Invention
The moving coil type electromagnetic linear actuator based on the composite Halbach array is designed, and aims to improve the self-shielding capacity of a magnetic circuit by adopting the composite Halbach array, and the permanent magnet can be fixed on a non-magnetic conductive material without an additional magnetic yoke, so that the assembly difficulty is reduced; meanwhile, the power density of the actuator can be obviously improved, and the contradiction between the driving requirement and the limited installation space is solved. The actuator has higher power density, lower assembly difficulty and higher research and practical value.
A moving-coil electromagnetic linear actuator based on a composite Halbach array is characterized by comprising: end cover (1), coil skeleton (2), yoke (3), solenoid group (4), main Halbach array layer (5), supplementary Halbach array layer (6), air gap (8), separate magnetic axis (9) and resonance spring (10), the leading features includes: the composite Halbach array comprises a main Halbach array layer (5) and an auxiliary Halbach array layer (6), wherein the main array layer is formed by alternately and closely arranging axial magnetizing permanent magnets (7.1) and radial magnetizing permanent magnets (7.2), and the auxiliary array layers alternately and closely arranged with the axial magnetizing permanent magnets (7.1) and magnetic conducting blocks (7.3) between the axial magnetizing permanent magnets and the magnetic conducting blocks are combined and fixed on a magnetism isolating shaft (9) to serve as a magnetic source; the magnetic yoke (3) and the magnetic source are fixed, and a gap between the magnetic yoke and the magnetic source is an air gap (8) and is used as a stator; the electromagnetic coil group (4) is embedded on the coil framework (2) and can do reciprocating linear motion in the air gap (8) to serve as an actuator; the composite Halbach array is arranged on one side of the electromagnetic coil group (4), and a main Halbach array layer (5) is close to the electromagnetic coil group (4).
The electromagnetic coil group (4) is composed of forward winding coils and reverse winding coils, the winding directions of the coils of the adjacent windings are opposite, wherein the number of the forward windings is m, the number of the reverse windings is n, m and n are positive integers, and m = n or m-n = +/-1.
The outer-layer main Halbach array (5) consists of p axial magnetizing permanent magnets (7.1) and k radial magnetizing permanent magnets (7.2); the inner-layer auxiliary Halbach array (6) consists of p axial magnetizing permanent magnets (7.4) and k magnetic conducting blocks (7.3) among the magnets; wherein p = k +1, and p and k are positive integers.
The number of windings of the electromagnetic coil group (5) and the number of radial magnetizing permanent magnets (7.1) or the number of magnetic conduction blocks (7.3) between the magnets meet the following requirements: k = m + n, and k, m, n are positive integers.
The resonance spring (10) is fixedly connected with the rotor, and the stator, the rotor and the resonance spring jointly form a resonance system; the direction and the magnitude of the current of the electromagnetic coil group (4) are adjusted through an electric control system to realize the required movement.
The moving-coil electromagnetic linear actuator based on the combined Halbach array adopts a coaxial cylindrical structure and can also adopt a flat structure form.
According to the moving coil type electromagnetic linear actuator based on the composite Halbach array, the composite Halbach array is adopted, the self-shielding capacity of a magnetic circuit is improved, the permanent magnet can be fixed on a non-magnetic conductive material, an extra magnetic yoke is not needed, and the assembly difficulty is reduced; meanwhile, the power density of the actuator can be obviously improved, and the contradiction between the driving requirement and the limited installation space is solved. The actuator has higher power density, lower assembly difficulty and higher research and practical value.
Compared with other technologies, the moving-coil electromagnetic linear actuator based on the composite Halbach array has the remarkable advantages that:
(1) the combined Halbach array can be used as an executing element of a control system and a driving device, the power density is improved, the volume is reduced, the contradiction between the driving requirement and the limited installation space can be effectively solved, and the high-speed, high-precision, linear and direct driving and control are ensured;
(2) the magnetic circuit of the composite Halbach array is self-shielded, an inner yoke is not needed, the size is reduced, and meanwhile, the processing and the installation are convenient;
(3) for different performance requirements and application targets, the moving-coil electromagnetic linear actuator can provide different parameter indexes, ensures the design flexibility of the actuator, and has wide application range.
The moving-coil electromagnetic linear actuator based on the composite Halbach array has the advantages of high power density, quick response, convenience in assembly and the like, and brings huge economic benefits after being put into industrial application.
Drawings
Fig. 1 is a schematic axial sectional structure view of an embodiment of the permanent magnet built-in type of the present invention, in which the arrow direction indicates the direction of magnetization of the permanent magnet.
Fig. 2 is a schematic axial sectional structure diagram of an embodiment of the invention with the permanent magnet arranged externally, wherein the arrow direction represents the magnetizing direction of the permanent magnet.
FIG. 3 is a steady state magnetic field finite element simulation magnetic force line distribution diagram of the composite Halbach array of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1 to 3, a moving-coil electromagnetic linear actuator based on a composite Halbach array includes: end cover (1), coil skeleton (2), yoke (3), solenoid group (4), main Halbach array layer (5), supplementary Halbach array layer (6), air gap (8), separate magnetic axis (9) and resonance spring (10), the leading features includes: the composite Halbach array comprises a main Halbach array layer (5) and an auxiliary Halbach array layer (6), wherein the main array layer is formed by alternately and closely arranging axial magnetizing permanent magnets (7.1) and radial magnetizing permanent magnets (7.2), and the auxiliary array layers alternately and closely arranged with the axial magnetizing permanent magnets (7.1) and magnetic conducting blocks (7.3) between the axial magnetizing permanent magnets and the magnetic conducting blocks are combined and fixed on a magnetism isolating shaft (9) to serve as a magnetic source; the magnetic yoke (3) and the magnetic source are fixed, and a gap between the magnetic yoke and the magnetic source is an air gap (8) and is used as a stator; the electromagnetic coil group (4) is embedded on the coil framework (2) and can do reciprocating linear motion in the air gap (8) to serve as an actuator; the composite Halbach array is arranged on one side of the electromagnetic coil group (4), and a main Halbach array layer (5) is close to the electromagnetic coil group (4).
The electromagnetic coil group (4) is composed of forward winding coils and reverse winding coils, the winding directions of the coils of the adjacent windings are opposite, wherein the number of the forward windings is m, the number of the reverse windings is n, m and n are positive integers, and m = n or m-n = +/-1.
The outer-layer main Halbach array (5) consists of p axial magnetizing permanent magnets (7.1) and k radial magnetizing permanent magnets (7.2); the inner-layer auxiliary Halbach array (6) consists of p axial magnetizing permanent magnets (7.4) and k magnetic conducting blocks (7.3) among the magnets; wherein p = k +1, and p and k are positive integers.
The number of windings of the electromagnetic coil group (5) and the number of radial magnetizing permanent magnets (7.1) or the number of magnetic conduction blocks (7.3) between the magnets meet the following requirements: k = m + n, and k, m, n are positive integers.
The resonant spring (10) is fixedly connected with the rotor, and the stator, the rotor and the resonant spring jointly form a resonant system; the direction and the magnitude of the current of the electromagnetic coil group (4) are adjusted through an electric control system to realize the required movement.
A moving-coil electromagnetic linear actuator based on a composite Halbach array adopts a coaxial cylindrical structure and can also adopt a flat structure form.
As shown in fig. 1, the moving coil type electromagnetic linear actuator based on the composite Halbach array according to the present invention is described in detail by taking the permanent magnet built-in type, the number of forward windings and the number of reverse windings m = n =1, the number of blocks k =2 of the radial magnetizing permanent magnet (7.2) and the magnetic conducting block (7.3) per Halbach array layer, and the number of blocks p =3 of the axial permanent magnet (7.1) per Halbach array layer as an example.
The static stable magnetic source is provided by a composite Halbach array, and a main Halbach array layer (5) is formed by sequentially and mutually clinging and arranging 2 radial magnetizing permanent magnets (7.2) and 3 axial magnetizing permanent magnets (7.1) to provide an air gap main magnetic field of generated output force; the auxiliary Halbach array layer (6) is composed of 3 axial magnetizing permanent magnets (7.1) and 2 magnetic conducting blocks (7.3), and each magnetic conducting block (7.3) is clamped between every two adjacent axial magnetizing permanent magnets (7.1) and is a traditional iron and magnetic array; the magnetic circuit of the auxiliary Halbach array layer (6) directly returns to the main magnetic circuit of the main Halbach array layer (5) through the axial magnetizing permanent magnet (7.1) and the magnetic conducting block (7.3) between the magnets, as shown in figure 3. Compared with the traditional Halbach array, the combined Halbach array can effectively reduce leakage magnetic flux and achieve a better magnetic self-shielding effect, the permanent magnet is fixed in the non-magnetic-conductive material, the assembly difficulty can be reduced, the size of the stator is obviously reduced, and in other words, the power density of the actuator can be effectively improved by adopting the combined Halbach array. More importantly, the magnetic reaction between the main array layer and the auxiliary array layer in the composite Halbach array has the functions of magnetic gathering effect and improving the air gap flux density, so that the driving force in a short stroke can be improved, and the Halbach array is particularly suitable for actuators. Meanwhile, the current-carrying electromagnetic coil group (5) is subjected to Lorentz force in a magnetic field generated by taking the composite Halbach array as a magnetic source, a moving part is driven to do linear motion, the output of thrust or power with different magnitudes can be realized by adjusting the magnitude of current, the armature reaction generated by electrifying can be eliminated to a certain extent by coil windings with different winding directions, and the stability and the electromechanical conversion efficiency of the actuator are improved.
Preferably, the permanent magnet is externally arranged on the electromagnetic coil, as shown in fig. 2, the relative volume of the permanent magnet can be increased under the condition that the volume of the motor is the same, the air gap flux density is increased, meanwhile, the externally arranged permanent magnet can directly carry out heat convection with the air in the space through a non-magnetic conductive material, an external cooling system can be arranged conveniently, and the heat dissipation performance and the ultimate working capacity of the actuator can be improved.
The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.

Claims (6)

1. A moving-coil electromagnetic linear actuator based on a composite Halbach array is characterized by comprising: end cover (1), coil skeleton (2), yoke (3), solenoid group (4), main Halbach array layer (5), supplementary Halbach array layer (6), air gap (8), separate magnetic axis (9) and resonance spring (10), the leading features includes: the composite Halbach array comprises a main Halbach array layer (5) and an auxiliary Halbach array layer (6), wherein the main array layer is formed by alternately and closely arranging axial magnetizing permanent magnets (7.1) and radial magnetizing permanent magnets (7.2), and the auxiliary array layers alternately and closely arranged with the axial magnetizing permanent magnets (7.1) and magnetic conducting blocks (7.3) between the axial magnetizing permanent magnets and the magnetic conducting blocks are combined and fixed on a magnetism isolating shaft (9) to serve as a magnetic source; the magnetic yoke (3) and the magnetic source are fixed, and a gap between the magnetic yoke and the magnetic source is an air gap (8) and is used as a stator; the electromagnetic coil group (4) is embedded on the coil framework (2) and can do reciprocating linear motion in the air gap (8) to serve as an actuator; the composite Halbach array is arranged on one side of the electromagnetic coil group (4), and a main Halbach array layer (5) is close to the electromagnetic coil group (4).
2. The moving-coil electromagnetic linear actuator based on the compound Halbach array as claimed in claim 1, wherein: the electromagnetic coil group (4) is composed of forward winding coils and reverse winding coils, the winding directions of the coils of the adjacent windings are opposite, wherein the number of the forward windings is m, the number of the reverse windings is n, m and n are positive integers, and m = n or m-n = +/-1.
3. The moving-coil electromagnetic linear actuator based on the compound Halbach array as claimed in claim 1, wherein: the outer-layer main Halbach array (5) consists of p axial magnetizing permanent magnets (7.1) and k radial magnetizing permanent magnets (7.2); the inner-layer auxiliary Halbach array (6) consists of p axial magnetizing permanent magnets (7.4) and k magnetic conducting blocks (7.3) among the magnets; wherein p = k +1, and p and k are positive integers.
4. A moving coil electromagnetic linear actuator based on a compound Halbach array as claimed in claims 1, 2 and 3, wherein: the number of windings of the electromagnetic coil group (5) and the number of radial magnetizing permanent magnets (7.1) or the number of magnetic conduction blocks (7.3) between the magnets meet the following requirements: k = m + n, and k, m, n are positive integers.
5. The moving-coil electromagnetic linear actuator based on the compound Halbach array as claimed in claims 1 and 3, wherein: the resonance spring (10) is fixedly connected with the rotor, and the stator, the rotor and the resonance spring jointly form a resonance system; the direction and the magnitude of the current of the electromagnetic coil group (4) are adjusted through an electric control system to realize the required movement.
6. The moving-coil electromagnetic linear actuator based on the compound Halbach array as claimed in claim 1, wherein: the moving-coil electromagnetic linear actuator based on the combined Halbach array adopts a coaxial cylindrical structure and can also adopt a flat structure form.
CN202010338750.5A 2020-04-26 2020-04-26 Moving-coil electromagnetic linear actuator based on composite Halbach array Active CN111416496B (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112542933A (en) * 2020-12-15 2021-03-23 淮阴工学院 Novel electromagnetism straight line is presented can semi-initiative suspension of formula
CN113483141A (en) * 2021-07-23 2021-10-08 山东大学 Moving-coil type gas pressure control valve and working method
CN114244062A (en) * 2021-12-21 2022-03-25 杭州电子科技大学 Linear reciprocating pump based on ferromagnetic structure and linear reciprocating driving method thereof

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101127474A (en) * 2007-09-19 2008-02-20 南京理工大学 High power density motive loop permanent magnetic linear electromotor
WO2011009397A1 (en) * 2009-07-21 2011-01-27 清华大学 Planar motor adopting three-dimensional permanent magnet array
CN102437701A (en) * 2011-12-27 2012-05-02 东南大学 Shore-based wave-power generator
CN105641763A (en) * 2016-04-12 2016-06-08 上海理工大学 Separated electromagnetic coupling blood pump system
WO2019083539A1 (en) * 2017-10-26 2019-05-02 Catalan Roberto Electromagnetic halbach array, devices, and methods
CN212258750U (en) * 2020-04-26 2020-12-29 山东理工大学 Moving-coil electromagnetic linear actuator based on combined Halbach array

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101127474A (en) * 2007-09-19 2008-02-20 南京理工大学 High power density motive loop permanent magnetic linear electromotor
WO2011009397A1 (en) * 2009-07-21 2011-01-27 清华大学 Planar motor adopting three-dimensional permanent magnet array
CN102437701A (en) * 2011-12-27 2012-05-02 东南大学 Shore-based wave-power generator
CN105641763A (en) * 2016-04-12 2016-06-08 上海理工大学 Separated electromagnetic coupling blood pump system
WO2019083539A1 (en) * 2017-10-26 2019-05-02 Catalan Roberto Electromagnetic halbach array, devices, and methods
CN212258750U (en) * 2020-04-26 2020-12-29 山东理工大学 Moving-coil electromagnetic linear actuator based on combined Halbach array

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
毛军红;罗俊航;姜强;谢友柏: "一种无铁心单边永磁同步直线电机及其永磁体阵列设计", 西安交通大学学报, no. 03, 20 March 2007 (2007-03-20) *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112542933A (en) * 2020-12-15 2021-03-23 淮阴工学院 Novel electromagnetism straight line is presented can semi-initiative suspension of formula
CN113483141A (en) * 2021-07-23 2021-10-08 山东大学 Moving-coil type gas pressure control valve and working method
CN114244062A (en) * 2021-12-21 2022-03-25 杭州电子科技大学 Linear reciprocating pump based on ferromagnetic structure and linear reciprocating driving method thereof
CN114244062B (en) * 2021-12-21 2022-12-30 杭州电子科技大学 Linear reciprocating pump based on ferromagnetic structure and linear reciprocating driving method thereof

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