A magnetostrictive precision rotary motor based on the Wiedemann effect

Abstract

The present invention belongs to the technical field of motors, and specifically relates to a magnetostrictive precision rotary motor based on the Wiedemann effect. The motor includes a pre-tightening plug, a rotor, an axial driver, a radial driver, a barrel-shaped permanent magnet, a housing, a friction hemisphere, a barrel-shaped magnetostrictive material structure, a disc spring, and a lower end cover; the friction hemisphere is closely attached to the spherical part of the rotor, and the flat part of the friction hemisphere is fixed on the barrel-shaped magnetostrictive material structure. The barrel-shaped permanent magnet is fixed on the disc spring, and the disc spring is fixed on the lower end cover; the radial driver is placed outside the barrel-shaped magnetostrictive material structure, and the axial driver is placed outside the radial driver; the pre-tightening plug and the lower end cover are screwed into the housing, and the straight rod of the rotor is placed in the rotary bearing of the pre-tightening plug. The present invention is a magnetostrictive precision rotary motor based on the Wiedemann effect with a simple and compact structure, strong load capacity, high rotational speed, strong stability, and low cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and specifically relates to a magnetostrictive precision rotary motor based on the Wiedemann effect. Background Art

[0002] With the continuous development of nanotechnology, the demand for drivers with stable performance and simple structures in technical fields such as aerospace, robotics, ultra-precision machining, and biology is also increasing. Although rotary motors with piezoelectric materials as the driving source have characteristics such as fast response speed and high deformation accuracy, their load capacity and rotational speed are not ideal enough.

[0003] The rotary motor made with the giant magnetostrictive material Terfenol-D as the driving source, although having advantages such as fast response speed, strong load, and large strain, its disadvantages are also obvious, including a large saturation magnetic field, poor mechanical properties, and high cost, which limit its application.

[0004] Compared with Terfenol-D material, Galfenol material has the advantages of fast response speed, smaller saturation magnetic field, stronger load capacity, excellent mechanical properties, and low cost, and is increasingly attracting people's attention. It is an ideal material for making rotary motors.

[0005] The giant magnetostrictive rotary motors designed in US Patents US5079460, US546015, and US5341056, although capable of providing large torques and precise positioning, have complex structures. Using multiple pieces of giant magnetostrictive materials results in too high cost. Driving the giant magnetostrictive materials with multi-channel signals makes its drive circuit complex.

[0006] Chinese Patents CN102013834A, CN102005967A, and CN102005966A use piezoelectric materials to make rotary motors that can achieve bidirectional rotation. These motors require two sets of piezoelectric wafers and drive signals, and cooperate with a phase difference in the design space to achieve their movement. However, due to the relatively high circuit drive voltage of piezoelectric materials, and their output torque is small, which limits their application scope. Patent CN102983778B designs a rotary motor based on giant magnetostrictive materials. By applying sinusoidal excitation signals with a certain phase difference, 4 pieces of giant magnetostrictive materials are driven. Through the friction generated between the stator and the rotor, the rotor is driven to rotate. Its cost is relatively high, it requires the cooperation between 4 different excitation signals, and there are also certain requirements for the processing technology, which to a certain extent limits its application scope. Patent CN102857140B designs a single-drive bidirectional rotary giant magnetostrictive rotary motor. Although this rotary motor has a simple structure and is easy to miniaturize, it requires a large magnetic field for driving.

[0007] A new type of elliptical drive giant magnetostrictive motor with high output, fast response, and good controllability is described in the literature "Design of Elliptical Drive Giant Magnetostrictive Motor". By controlling two giant magnetostrictive actuators connected by an intermediate elastic ring, a micro-displacement motor is constructed. When two-phase orthogonal sinusoidal currents are applied to the two motors respectively, an elliptical modal motion is generated at the contact between the stator and the rotor. This rotary motor is driven by two giant magnetostrictive actuators, which has high cost, large volume, and complex structure, restricting its large-scale popularization and use.

[0008] Regarding the problems existing in the above-mentioned prior art, such as high cost, insufficient driving force, small output torque, and complex circuit, it is of certain significance to study a rotary motor driven by barrel-shaped magnetostrictive material Galfenol. Summary of the Invention

[0009] The object of the present invention is to provide a magnetostrictive precision rotary motor based on the Wiedemann effect, which has a simple and compact structure, strong load capacity, fast rotational speed, strong stability, and low cost, aiming to solve the problems.

[0010] The technical solution adopted by the present invention to solve the above technical problems: Utilize the magnetostrictive effect and Wiedemann effect of barrel-shaped magnetostrictive material Galfenol to drive a friction ball, and rely on the frictional force between the friction hemisphere and the rotor to drive the rotor to rotate.

[0011] The specific technical solution is as follows: A magnetostrictive precision rotary motor based on the Wiedemann effect, which includes a pre-tightening plug, a rotor, a radial driver, an axial driver, a barrel-shaped permanent magnet, a housing, a friction hemisphere, a barrel-shaped magnetostrictive material structure, a disc spring, and a lower end cover;

[0012] The spherical part of the friction hemisphere is closely attached to the spherical part of the rotor, and the flat part of the friction hemisphere is fixed on the barrel-shaped magnetostrictive material structure. The barrel-shaped permanent magnet is placed on the disc spring, and the disc spring is placed on the lower end cover;

[0013] The axial driver is placed outside the radial driver, and the radial driver is placed outside the barrel-shaped magnetostrictive material structure;

[0014] The pre-tightening plug and the lower end cover are screwed into the housing, and the straight rod of the rotor is placed in the rotary bearing of the pre-tightening plug.

[0015] Furthermore, for the rotary bearing at the bottom of the pre-tightening plug, its bottom surface is tangent to the spherical surface of the rotor.

[0016] Furthermore, the N pole of the barrel-shaped permanent magnet is fixed on the barrel-shaped magnetostrictive material structure, and the S pole is placed on the disc spring.

[0017] Furthermore, the pre-tightening plug consists of a rotary bearing and a cylinder; there are 2 rotary bearings in total, embedded in the cylinder, and the outer surface of the cylinder has threads and is matched with the housing.

[0018] Furthermore, the rotor consists of a straight rod and a sphere; the straight rod is embedded and fixed in the sphere.

[0019] Furthermore, the axial driver includes: a "work"-shaped hollow cylindrical bobbin and an axial drive coil, and the axial drive coil is tightly wound on the bobbin.

[0020] Furthermore, the radial driver includes 6 H-shaped bobbins and radial drive coils. The 6 H-shaped bobbins are arranged in a hexagon along the barrel-shaped magnetostrictive material structure. The radial drive coils are tightly wound on the H-shaped bobbins, and the radial drive coils on each H-shaped bobbin are connected in series.

[0021] Furthermore, the lower end cover consists of an upward convex column, a cylinder and a handle;

[0022] wherein the upward convex column is placed in the hollow of the disc spring to fix the axial bobbin; the outer surface of the cylinder has threads and is matched with the housing, and the lower end cover is screwed into the housing through the handle.

[0023] Its working principle is as follows:

[0024] The current cycles of the axial and radial drivers can be divided into 4 stages. In the first stage, no current is input to the axial and radial drive coils. At this time, the axial magnetic field is mainly provided by the barrel-shaped permanent magnet. Under the axial magnetic field, the barrel-shaped magnetostrictive material structure generates a small upward deformation, which is more conducive to the fit between the friction hemisphere and the spherical part of the rotor. The radial magnetic field is 0. In the second stage, currents start to be slowly input to both the radial and axial drive coils. As the current gradually reaches the maximum value, the axial and radial magnetic fields also reach the maximum value. In the third stage, the current input to the axial drive coil rapidly decreases to a negative value, while the current in the radial drive coil remains unchanged. At this time, the axial magnetic field rapidly decreases to be lower than the magnetic field in the first stage, and the radial magnetic field remains unchanged. In the fourth stage, the axial current remains negative and unchanged, while the radial current rapidly decreases to 0. At this time, the axial magnetic field remains unchanged, and the radial magnetic field rapidly decreases to 0.

[0025] When the magnetic field is clockwise after the current is applied to the coil wound on the radial driver, the specific driving process of the barrel-shaped magnetostrictive material structure within the current cycles of the axial and radial drivers is as follows: In the first stage, when no current is input to the axial driver coil and the radial driver coil, the barrel-shaped magnetostrictive material structure elongates upward axially under the action of the axial bias magnetic field of the barrel-shaped permanent magnet, generating a small deformation. In the second stage, current starts to be slowly applied to both the radial and axial drive coils. As the current gradually reaches its maximum value, the axial magnetic field and the radial magnetic field also reach their maximum values. Under the combined action of the axial and radial magnetic fields, a helical magnetic field is generated. Initially, due to the small helical magnetic field, the frictional force generated between the friction hemisphere and the spherical part of the rotor is small, and the rotor does not twist. When the axial and radial currents reach their maximum values, the maximum static frictional force is generated between the friction hemisphere and the spherical part of the rotor, and the rotor twists. The rotor rotates through an angle of θ from its original position and remains unchanged. During the elongation and twisting process of the barrel-shaped magnetostrictive material structure, it can be regarded as being jointly completed by two processes: 1. Under the axial magnetic field, the barrel-shaped magnetostrictive material structure is driven by the axial magnetic field and elongates upward axially. When the axial magnetic field reaches its maximum value, the elongation also reaches its maximum. The degree of fit between the friction hemisphere and the spherical part of the rotor becomes closer as the magnetic field increases; 2. Under the axial magnetic field and the radial magnetic field, the barrel-shaped magnetostrictive material structure twists clockwise. When the axial and radial magnetic fields reach their maximum values, the torque reaches its maximum value. In the third stage, the current applied to the axial coil rapidly decreases to a negative value, while the current in the radial coil remains unchanged. At this time, the barrel-shaped magnetostrictive material structure shortens downward axially, and the degree of fit between the spherical part of the friction hemisphere and the spherical part of the rotor decreases. The radial magnetic field remains unchanged, and the barrel-shaped magnetostrictive material structure still twists clockwise. In the fourth stage, the axial drive current remains negative and unchanged; the radial drive current rapidly decreases to 0. At this time, the axial magnetic field remains unchanged, while the radial magnetic field rapidly decreases to 0. The axial elongation of the barrel-shaped magnetostrictive material structure is the same as that in the third stage. As the radial magnetic field decreases to 0, the clockwise-twisting barrel-shaped magnetostrictive material structure rapidly reverses. At this time, since the frictional force between the friction hemisphere and the spherical part of the rotor is too small, the rotor does not twist. When current is continuously applied, the rotor rotates clockwise through continuous twisting. Similarly, when the magnetic field direction is counterclockwise after the current is applied to the coil wound on the radial driver, the rotating motor rotates counterclockwise.

[0026] Advantages of the present invention: The rotating motor driven by the barrel-shaped magnetostrictive material Galfenol of the present invention has a simple and compact structure, strong load capacity, high rotational speed, strong stability, and low cost. By changing the direction of the coil magnetic field of the radial driver, the rotor can be rotated in the clockwise / counterclockwise directions, and it can be applied in fields such as aerospace, robotics, and ultra-precision machining. Description of the Drawings

[0027] Figure 1 are the axial and radial driver currents of the present invention, and their corresponding driving magnetic fields.

[0028] Figure 2 is a schematic diagram of the clockwise rotation direction of the present invention.

[0029] Figure 3 is a schematic diagram of the counterclockwise rotation direction of the present invention.

[0030] Figure 4 is a schematic cross-sectional structure diagram of the present invention.

[0031] Figure 5 is a schematic front structure diagram of the whole of the present invention.

[0032] Figure 6 is a schematic structure diagram of the friction ball, the barrel-shaped magnetostrictive material structure, and the barrel-shaped permanent magnet of the present invention.

[0033] Figure 7 is a schematic structure diagram of the pre-tightening plug of the invention.

[0034] Figure 8 is a schematic structure diagram of the rotor of the present invention.

[0035] Figure 9 is a schematic structure diagram of the radial driver of the present invention.

[0036] Figure 10 is a schematic structure diagram of the axial driver of the present invention.

[0037] Figure 11 is a schematic structure diagram of the housing of the present invention.

[0038] Figure 12 is a schematic structure diagram of the disc spring of the present invention.

[0039] Figure 13 is a schematic structure diagram of the lower end cover of the present invention. Detailed Embodiments

[0040] The present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0041] Figure 2 is a schematic diagram of the clockwise rotation of the motor, where the left figure shows the clockwise rotation of the rotating motor by an angle θ from the original position, and the right figure shows the clockwise helical magnetic field generated when the axial driver coil and the radial driver coil (the current generates a clockwise magnetic field) act together.

[0042] Figure 3 It is a schematic diagram of the counterclockwise rotation of the motor. The left figure shows that the rotating motor rotates counterclockwise by an angle θ from the original position, and the right figure shows the counterclockwise helical magnetic field generated when the axial drive coil and the radial drive coil (the current generates a counterclockwise magnetic field) act together.

[0043] Refer to Figure 4 — Figure 13 This rotating motor is composed of a pre-tightening plug 1, a rotor 2, a radial driver 3, an axial driver 4, a permanent magnet 5, a housing 6, a friction hemisphere 7, a barrel-shaped magnetostrictive material structure 8, a disc spring 9, and a lower end cover 10.

[0044] Among them, the friction hemisphere 7 and the rotor 2 are in contact through the cooperation between the pre-tightening plug 1 and the housing 6. The friction ball 7 is fixed on the barrel-shaped magnetostrictive material structure 8, the barrel-shaped magnetostrictive material structure 8 is fixed on the barrel-shaped permanent magnet 5, the barrel-shaped permanent magnet 5 is fixed on the disc spring 9, and the disc spring 9 is fixed on the lower end cover 10;

[0045] The radial driver 3 is placed outside the barrel-shaped magnetostrictive material structure 8, and the axial driver 4 is placed outside the radial driver 3; the pre-tightening plug 1 and the lower end cover 10 are screwed into the housing 6. The straight rod 201 of the rotor is placed in the rotary bearing 101 of the pre-tightening plug, and the bottom end 101 of the rotary bearing is tangent to the surface of the sphere 202 of the rotor 2.

[0046] The N pole of the barrel-shaped permanent magnet 5 is fixed on the barrel-shaped magnetostrictive material Galfenol, and the S pole is fixed on the disc spring 9.

[0047] The pre-tightening plug 1 is composed of a rotary bearing 101 and a cylinder 102.

[0048] There are 2 rotary bearings 101 in total. The outer surface of the inner cylinder of the cylinder (102) in which they are embedded has threads and can cooperate with the housing 6.

[0049] The rotor 2 is composed of a straight rod 201 and a sphere 202. The straight rod is embedded and fixed in the sphere. The materials of the straight rod and the sphere are both made of smooth No. 45 steel.

[0050] The radial driver includes 3 including 6 H-shaped coil holders 301, radial line drive coils 302, and straight notches 303. The coil holders are made of non-magnetic material copper, and the axial drive coil is made of enameled wire. The axial drive coil is tightly wound on the H-shaped coil holder. When the direction of the applied current is clockwise, a clockwise magnetic field is generated; when the direction of the applied current is counterclockwise, a counterclockwise magnetic field is generated.

[0051] The axial driver 4 includes a "work" - shaped hollow cylindrical bobbin 401 and an axial drive coil 402. The radial driver coil is made of enameled wire. The axial drive coil is closely wound around the "work" - shaped hollow cylindrical bobbin.

[0052] The housing 6 is made of the magnetic conductive material iron, which can reduce magnetic leakage.

[0053] The lower end - cover 10 is composed of an upper convex column 1001, a cylinder 1002 and a handle 1003.

[0054] Among them, the upper convex column is inserted into the hollow of the axial bobbin 401 to fix the axial bobbin. The upper surface of the cylinder 1002 has threads and can cooperate with the housing 6. The lower end - cover can be screwed into the housing through the handle 1003. The lower end - cover 10 is made of the magnetic conductive material iron.

[0055] Its working principle is as follows:

[0056] The current cycles of the axial and radial drivers can be divided into 4 stages. In the first stage, no current is input to both the axial and radial coils. At this time, the axial magnetic field is mainly provided by the barrel - shaped permanent magnet, and the radial magnetic field is 0. In the second stage, current starts to be slowly input to both the radial and axial coils. As the current gradually reaches the maximum value, the axial magnetic field and the radial magnetic field also reach the maximum value. In the third stage, the current input to the axial coil rapidly decreases to a negative value, while the current in the radial coil remains unchanged. At this time, the axial magnetic field rapidly decreases to a value lower than that in the first stage, and the radial magnetic field remains unchanged. In the fourth stage, the axial current remains negative and unchanged, while the radial current rapidly decreases to 0. At this time, the axial magnetic field remains unchanged, and the radial magnetic field rapidly decreases to 0.

[0057] The current cycles of the axial and radial drivers can be divided into 4 stages. In the first stage, no current is input to both the axial and radial drive coils. At this time, the axial magnetic field is mainly provided by the barrel - shaped permanent magnet. Under the axial magnetic field, the structure of the barrel - shaped magnetostrictive material generates a small upward deformation, making it easier for the friction between the hemisphere and the spherical part of the rotor to fit. The radial magnetic field is 0. In the second stage, current starts to be slowly input to both the radial and axial drive coils. As the current gradually reaches the maximum value, the axial magnetic field and the radial magnetic field also reach the maximum value. In the third stage, the current input to the axial drive coil rapidly decreases to a negative value, while the current in the radial drive coil remains unchanged. At this time, the axial magnetic field rapidly decreases to a value lower than that in the first stage, and the radial magnetic field remains unchanged. In the fourth stage, the axial current remains negative and unchanged, while the radial current rapidly decreases to 0. At this time, the axial magnetic field remains unchanged, and the radial magnetic field rapidly decreases to 0.

[0058] When the magnetic field is clockwise after the current is applied to the coil wound on the radial driver, the specific driving process of the barrel-shaped magnetostrictive material structure within the current cycle of the axial and radial drivers is as follows: In the first stage, when no current is input to the coils of the axial driver and the radial driver, the barrel-shaped magnetostrictive material structure elongates upward along the axis under the action of the axial bias magnetic field of the barrel-shaped permanent magnet, generating a small deformation. In the second stage, current starts to be slowly applied to both the radial and axial driving coils. As the current gradually reaches its maximum value, the axial magnetic field and the radial magnetic field also reach their maximum values. Under the combined action of the axial and radial magnetic fields, a helical magnetic field is generated. Initially, due to the small helical magnetic field, the frictional force generated between the friction hemisphere and the spherical part of the rotor is small, and the rotor does not twist. When the axial and radial currents reach their maximum values, the maximum static frictional force is generated between the friction hemisphere and the spherical part of the rotor, and the rotor twists. The rotor rotates through an angle of θ from its original position and remains unchanged. During the elongation and twisting process of the barrel-shaped magnetostrictive material structure, it can be regarded as being jointly completed by two processes: 1. Under the axial magnetic field, the barrel-shaped magnetostrictive material structure is driven by the axial magnetic field and elongates upward along the axial direction. When the axial magnetic field reaches its maximum value, the elongation also reaches its maximum. The degree of fit between the friction hemisphere and the spherical part of the rotor becomes closer as the magnetic field increases; 2. Under the axial magnetic field and the radial magnetic field, the barrel-shaped magnetostrictive material structure twists clockwise. When the axial and radial magnetic fields reach their maximum values, the torque reaches its maximum value. In the third stage, the current applied to the axial coil rapidly decreases to a negative value, while the current in the radial coil remains unchanged. At this time, the barrel-shaped magnetostrictive material structure shortens downward along the axis, and the degree of fit between the spherical part of the friction hemisphere and the spherical part of the rotor decreases. The radial magnetic field remains unchanged, and the barrel-shaped magnetostrictive material structure still twists clockwise. In the fourth stage, the axial driving current remains negative and unchanged; the radial driving current rapidly decreases to 0. At this time, the axial magnetic field remains unchanged, while the radial magnetic field rapidly decreases to 0. The axial elongation of the barrel-shaped magnetostrictive material structure is the same as that in the third stage. As the radial magnetic field decreases to 0, the clockwise-twisting barrel-shaped magnetostrictive material structure rapidly reverses. At this time, since the frictional force between the friction hemisphere and the spherical part of the rotor is too small, the rotor does not twist. When current is continuously applied, the rotor rotates clockwise through continuous twisting. Similarly, when the magnetic field direction is counterclockwise after the current is applied to the coil wound on the radial driver, the rotating motor rotates counterclockwise.

[0059] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A magnetostrictive precision rotary motor based on the Wiedemann effect, characterized in that: The motor includes a pre-tightening plug (1), a rotor (2), a radial driver (3), an axial driver (4), a barrel-shaped permanent magnet (5), a housing (6), a friction hemisphere (7), a barrel-shaped magnetostrictive material structure (8), a disc spring (9), and a lower end cover (10); The friction hemisphere (7) is in close contact with the rotor (2), that is: the spherical part of the friction hemisphere (7) is tangent to the spherical part of the rotor (2). The friction hemisphere (7) is fixed on the barrel-shaped magnetostrictive material structure (8), the barrel-shaped magnetostrictive material structure (8) is fixed on the barrel-shaped permanent magnet (5), the barrel-shaped permanent magnet (5) is fixed on the disc spring (9), and the disc spring (9) is fixed on the lower end cover (10); The radial driver (3) is placed outside the barrel-shaped magnetostrictive material structure (8). The inner surface of the axial driver (4) is tangent to the radial driver (3), making the structure more compact. The radial driver (3) is outside the barrel-shaped magnetostrictive material structure (8) and maintains a small distance from the barrel-shaped magnetostrictive material structure (8) to prevent the barrel-shaped magnetostrictive material structure (8) from touching the radial driver (3) when rotating; The pre-tightening plug (1) and the lower end cover (10) are screwed into the housing (6). The straight rod (201) of the rotor (2) is placed in the rotary bearing (101) of the pre-tightening plug (1); The bottom end of the rotary bearing (101) is tangent to the surface of the sphere (202) of the rotor (2); The pre-tightening plug (1) consists of a rotary bearing (101) and a cylinder (102); there are 2 rotary bearings (101) in total, which are embedded in the cylinder (102). The outer surface of the cylinder (102) has threads and can cooperate with the housing (6); The rotor (2) consists of a straight rod (201) and a sphere (202); the straight rod (201) is embedded in the sphere (202).

2. The magnetostrictive precision rotary motor based on the Wiedemann effect according to claim 1, wherein: The N pole of the barrel-shaped permanent magnet (5) is fixed on the barrel-shaped magnetostrictive material structure (8), and the S pole is fixed on the disc spring (9).

3. The magnetostrictive precision rotary motor based on the Wiedemann effect according to claim 1, characterized in that: The radial driver (3) includes 6 H-shaped coil holders (301) and a radial drive coil (302). The radial drive coil (302) is tightly wound around the H-shaped coil holder (301). In order to close the magnetic circuit, a straight slot (303) is opened in the middle of the H-shaped coil holder. In order to generate a toroidal magnetic field, the 6 H-shaped coil holders (302) are arranged in a hexagon, and each radial drive coil is connected in series; 4. The magnetostrictive precision rotary motor based on the Wiedemann effect according to claim 1, characterized in that: The axial driver (4) includes an "I"-shaped cylindrical coil holder (401) and an axial drive coil (402). The axial drive coil (402) is tightly wound around the "I"-shaped cylindrical coil holder (401).

5. The magnetostrictive precision rotary motor based on the Wiedemann effect according to claim 1, characterized in that: The lower end cover (10) consists of an upper convex column (1001), a cylinder (1002), and a handle (1003); the upper convex column (1001) is placed in the hollow of the disc spring (9) to prevent the disc spring (9) from moving; the outer surface of the cylinder (1002) has threads and cooperates with the housing (6). The lower end cover (10) can be screwed into the housing (6) through the handle (1003).

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