A core motor with a coil that suppresses magnetic saturation and armature reaction effects

Abstract

The application discloses a kind of iron core voice coil motor for inhibiting magnetic saturation and armature reaction influence, it is related to motor technical field, including stator assembly and rotor assembly;The stator assembly includes magnetic yoke structure and permanent magnet structure;The magnetic yoke structure includes multiple magnetic conductive components, and the multiple magnetic conductive components are symmetrical closed magnetic circuit structure as a whole;The application is arranged by first magnetic group, second magnetic group of symmetrical arrangement reverse magnetization, and two groups of coil winding of equal reverse current are input, the armature magnetic field is completely cancelled, the magnetic density inside magnetic yoke structure is always uniform and symmetrical after energization, there is no local magnetic density distortion, avoid the core magnetic saturation from the root, solve the core defects of traditional motor thrust nonlinearity under large current.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to an iron-core voice coil motor that suppresses the effects of magnetic saturation and armature reaction. Background Technology

[0002] Voice coil motors are direct-drive motors characterized by fast response, high thrust density, and high positioning accuracy, making them widely used in precision positioning equipment, automated production lines, medical devices, and optical instruments. Voice coil motors come in various structural forms, including iron-core voice coil motors with rectangular and arc-shaped structures. These motors, due to their iron-core structure, can achieve higher thrust density and are suitable for applications requiring greater thrust.

[0003] Existing voice coil motors with iron cores are affected by core magnetic saturation and armature reaction under high current conditions. Their thrust no longer increases linearly with current, and the thrust constant cannot remain constant, affecting the motor's control performance and hindering high-precision applications. Current technologies primarily address magnetic saturation by increasing the core thickness (i.e., increasing the cross-sectional area of ​​the magnetic circuit). However, this increases the overall motor thickness and size, hindering miniaturization and high thrust density applications. The other approach involves an air gap cavity in the yoke to increase magnetic reluctance and prevent saturation, but this reduces the air gap magnetic flux density, leading to a decrease in thrust. Furthermore, neither of these solutions effectively addresses the effects of armature reaction or core losses. Summary of the Invention

[0004] This invention provides a core-driven voice coil motor that suppresses the effects of magnetic saturation and armature reaction, solving the problems of thrust nonlinearity and poor control accuracy caused by magnetic saturation and armature reaction in existing core-driven voice coil motors during high-current operation.

[0005] To achieve the above object, a coreless voice coil motor for suppressing the influence of magnetic saturation and armature reaction provided by the present invention includes a stator assembly and a mover assembly; the stator assembly includes a yoke structure and a permanent magnet structure; the yoke structure includes multiple segments of magnetic conductive members, and the multiple segments of magnetic conductive members as a whole form a symmetrically closed magnetic circuit structure; the permanent magnet structure is divided into a first magnetic group and a second magnetic group, and the two magnetic groups are symmetrically arranged in the internal cavity of the yoke structure, and the overall magnetization directions of the first magnetic group and the second magnetic group are symmetrically arranged in the opposite direction; the mover assembly includes a first coil winding, a second coil winding and an insulating support skeleton, the first coil winding and the second coil winding are both fixedly installed on the insulating support skeleton, the first coil winding extends into the air gap between the first magnetic group and the yoke structure, and the second coil winding extends into the air gap between the second magnetic group and the yoke structure; the electrical parameters and structural dimensions of the first coil winding and the second coil winding are exactly the same, and equal and opposite currents are passed through the first coil winding and the second coil winding during operation.

[0006] Preferably, the multiple segments of magnetic conductive members include a first yoke, a second yoke and a third yoke, the first yoke is the left and right end covers, the second yoke is the upper and lower back plates, the third yoke is the middle iron core, and the first yoke, the second yoke and the third yoke together form a symmetrically closed magnetic circuit structure in the shape of "曰".

[0007] Preferably, the first magnetic group is fixedly installed in the cavity between the left first yoke and the third yoke, and includes a first permanent magnet and a second permanent magnet symmetrically arranged in the vertical direction; the magnetization direction of the first permanent magnet is vertically downward, and the magnetization direction of the second permanent magnet is vertically upward.

[0008] Preferably, the second magnetic group is fixedly installed in the cavity between the right first yoke and the third yoke, and includes a third permanent magnet and a fourth permanent magnet symmetrically arranged in the vertical direction; the magnetization direction of the third permanent magnet is vertically upward, and the magnetization direction of the fourth permanent magnet is vertically downward.

[0009] Preferably, the first coil winding is coil winding A, the second coil winding is coil winding B, and the insulating support skeleton is a coil skeleton; coil winding A is adaptively embedded in the air gap between the first magnetic group and the third yoke, and coil winding B is adaptively embedded in the air gap between the second magnetic group and the third yoke, and the two coil windings are coaxially symmetrically arranged.

[0010] Preferably, the first yoke, the second yoke and the third yoke are all made of magnetic conductive materials.

[0011] Preferably, the coil skeleton is made of non-magnetic conductive materials.

[0012] Preferably, both coil winding A and coil winding B are wound with copper wires.

[0013] Preferably, the thickness of the third yoke ranges from 5 mm to 15 mm.

[0014] Compared with the related art, a coreless voice coil motor for suppressing the influence of magnetic saturation and armature reaction provided by the present invention has the following beneficial effects:

[0015] By symmetrically arranging the first magnetic group and the second magnetic group with reverse magnetization and passing equal and opposite currents through two coil windings, the present invention achieves complete cancellation of the armature magnetic field. After power-on, the magnetic flux density inside the yoke structure is always uniform and symmetric, without local magnetic flux density distortion, avoiding core magnetic saturation at the source and solving the core defect of non-linear thrust under large currents in traditional motors.

[0016] The changing trends of the thrust constants of the two coil windings of the present invention are complementary. After superposition, the total thrust constant is close to being constant, and the thrust maintains a linear relationship with the input current, greatly improving the positioning accuracy and control stability of the motor and adapting to high-precision precision drive scenarios.

[0017] After the armature magnetic field of the present invention is cancelled, the magnetic flux density fluctuation inside the yoke is small, effectively reducing the hysteresis loss and eddy current loss. Compared with the traditional coreless voice coil motor, the core loss is reduced by more than 60%, the energy efficiency of the motor is significantly improved, the problem of running heat generation is alleviated, and the service life is extended.

[0018] The present invention does not need to avoid magnetic saturation by thickening the core or increasing the magnetic circuit cross-sectional area. The middle core only needs to meet the minimum thickness for structural rigidity and assembly strength, and the thrust output does not change with the increase in the core thickness. While ensuring high thrust density, the volume of the motor is greatly reduced, and the structural compactness is optimized.

[0019] The "day"-shaped symmetric closed magnetic circuit structure of the present invention has a complete magnetic circuit without breakpoints, high utilization rate of magnetic conductive materials. With the symmetric magnetic group and coil layout, the motor has strong operation stability, taking into account the dual advantages of large thrust output and high-precision control. Description of the Drawings

[0020] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 is a schematic diagram of the main magnetic field magnetic flux density distribution of a traditional coreless voice coil motor;

[0022] Figure 3 is a schematic diagram of the magnetic flux density distribution of the vector synthesis magnetic field of a traditional coreless voice coil motor;

[0023] Figure 4 is a schematic diagram of the main magnetic field magnetic flux density distribution of the present invention;

[0024] Figure 5 is a schematic diagram of the magnetic flux density distribution of the vector synthesis magnetic field of the present invention;

[0025] Figure 6 Schematic diagram of B-H curve of magnetic yoke magnetic conductive material

[0026] Figure 7 Schematic diagram of asymmetric distribution of magnetic flux density of traditional iron-core voice coil motor

[0027] Figure 8 Schematic diagram of change of thrust constant of traditional iron-core voice coil motor

[0028] Figure 9 Schematic diagram of symmetric distribution of magnetic flux density of the present invention

[0029] Figure 10 Schematic diagram of change of thrust constants of coil winding A, coil winding B and total thrust of the present invention

[0030] Figure 11 Iron core loss of traditional structure

[0031] Figure 12 Iron core loss of the present invention

[0032] Figure 13 Schematic diagram of change of thrust with parametric scanning of iron core thickness

[0033] Reference numerals in the figure: 1, first magnetic yoke; 2, second magnetic yoke; 3, third magnetic yoke; 4, first magnetic group; 41, first permanent magnet; 42, second permanent magnet; 5, second magnetic group; 51, third permanent magnet; 52, fourth permanent magnet; 6, coil winding A; 7, coil winding B; 8, coil skeleton Detailed implementation mode

[0034] The following further elaborates on the above and other technical features and advantages of the present invention with reference to the accompanying drawings

[0035] Embodiment 1

[0036] The iron-core voice coil motor for suppressing the influence of magnetic saturation and armature reaction provided in this embodiment includes a stator assembly and a mover assembly

[0037] The stator assembly includes a magnetic yoke structure and a permanent magnet structure; the magnetic yoke structure includes a first magnetic yoke 1, a second magnetic yoke 2 and a third magnetic yoke 3. The first magnetic yoke 1 is the left and right end covers, the second magnetic yoke 2 is the upper and lower back plates, and the third magnetic yoke 3 is the middle iron core. The first magnetic yoke 1, the second magnetic yoke 2 and the third magnetic yoke 3 together form a "曰"-shaped integral magnetic yoke. The first magnetic yoke 1, the second magnetic yoke 2 and the third magnetic yoke 3 are all made of magnetic conductive materials, which can form a complete closed magnetic circuit to ensure the effective conduction of the magnetic field

[0038] The permanent magnet structure includes a first magnetic group 4 and a second magnetic group 5. The first magnetic group 4 is disposed between the first magnetic yoke 1 and the third magnetic yoke 3 on the left side, including an upper first permanent magnet 41 and a lower second permanent magnet 42. The magnetization direction of the first permanent magnet 41 is vertically downward, and the magnetization direction of the second permanent magnet 42 is vertically upward. The second magnetic group 5 is disposed between the first magnetic yoke 1 and the third magnetic yoke 3 on the right side, including an upper third permanent magnet 51 and a lower fourth permanent magnet 52. The magnetization direction of the third permanent magnet 51 is vertically upward, and the magnetization direction of the fourth permanent magnet 52 is vertically downward. The arrangement of the permanent magnets can form magnetic fields with opposite directions in the corresponding air gaps, providing a magnetic field basis for the coil to generate thrust.

[0039] The mover assembly includes coil winding A6, coil winding B7, and coil frame 8. The coil frame 8 is made of non-magnetic material to avoid interference with the magnetic circuit and ensure the normal distribution of the magnetic field. Both coil winding A6 and coil winding B7 are made of copper wire, and their shape, material, cross-sectional area, volume, and number of turns are identical. Coil winding A6 is located in the air gap between the first magnetic group 4 and the third magnetic yoke 3 on the left, and coil winding B7 is located in the air gap between the second magnetic group 5 and the third magnetic yoke 3 on the right. The currents in coil winding A6 and coil winding B7 are equal in magnitude and opposite in direction at every moment. According to Ampere's left-hand rule, the direction of the magnetic field in coil winding A6 is opposite to the direction of the magnetic field in coil winding B7. At the same time, the currents in both are opposite in direction, so their thrust directions are the same and can be combined to form the total thrust of the motor. In addition, the armature magnetic fields generated by coil winding A6 and coil winding B7 are equal in magnitude and opposite in direction, which can cancel each other out, thereby avoiding the influence of the armature magnetic field on the main magnetic field.

[0040] During motor operation, the structure of this embodiment can effectively suppress the effects of magnetic saturation and armature reaction, and reduce core losses, as detailed below:

[0041] 1. Suppress the effects of magnetic saturation

[0042] Traditional voice coil motors with iron cores generate their main magnetic field solely through permanent magnets when not powered. The magnetic flux density distribution of these magnets is symmetrical about the motor's central axis. Figure 2 As shown; when the coil is energized, the armature magnetic field generated by the coil is vector-combined with the main magnetic field. At this time, the magnetic flux density distribution is no longer symmetrical, and the magnetic flux density at the right end of the central iron core is significantly enhanced, as shown. Figure 3 As shown, this will lead to a significant increase in the magnetic flux density of the yoke, approaching magnetic saturation, and affecting the thrust performance of the motor.

[0043] In this embodiment, when the motor is not powered on, the magnetic flux density distribution of the main magnetic field is as follows: Figure 4 As shown; when the coil is energized, the magnetic flux density distribution after the main magnetic field and the armature magnetic field are combined is as follows. Figure 5 As shown, the magnetic flux density distribution of the magnetic field before and after the coil is energized is basically the same. This is because the armature magnetic fields generated by coil winding A6 and coil winding B7 are equal in magnitude and opposite in direction, canceling each other out. This effectively avoids the superposition effect of the armature magnetic field on the main magnetic field, thereby suppressing the occurrence of magnetic saturation. Therefore, the motor of this application does not need to increase the thickness of the iron core to prevent magnetic saturation. The thickness of the third magnetic yoke 3 only needs to ensure the hole depth of the rigid connection, which can reduce the volume of the motor and increase the thrust density.

[0044] 2. Influence of suppressing armature reaction

[0045] In traditional iron-core voice coil motors, the magnetic material used for the yoke has nonlinear magnetization characteristics, and its relationship curve between magnetic induction intensity and magnetic field strength (BH curve) is as follows: Figure 6 As shown; when the coil is energized, the armature magnetic field and the main magnetic field are superimposed. Due to the nonlinear magnetization characteristics of the material, the strengthening effect of the magnetic field is less than the weakening effect, resulting in an asymmetrical magnetic flux density distribution, such as... Figure 7 As shown, this will cause the motor's thrust constant to decrease as the current increases, such as Figure 8 As shown, the thrust cannot increase linearly with the current, which seriously affects the control performance of the motor and makes it unsuitable for high-precision applications.

[0046] In the motor of this embodiment, because the armature magnetic fields of coil winding A6 and coil winding B7 cancel each other out, the magnetic flux density distribution remains symmetrical after energization. Figure 9 As shown; Figure 10 As shown, the thrust constant of coil winding A6 decreases approximately linearly with increasing current; the thrust constant of coil winding B7 increases approximately linearly with increasing current; after the thrust vector of the two is combined, the total thrust constant is approximately constant with increasing current, which effectively solves the influence of armature reaction, ensures the control performance of the motor, and is suitable for high-precision application scenarios.

[0047] 3. Reduce core loss

[0048] The core loss state of a traditional voice coil motor with an iron core under sinusoidal current excitation of 1A and 50Hz is as follows: Figure 11 As shown, the average core loss is 12.35 mW, of which the average eddy current loss is 3.18 mW and the average hysteresis loss is 9.17 mW; while the improved structure of this application, under the same current excitation, as Figure 12 As shown, the average core loss is 4.72mW, which is 61.8% lower than that of the traditional structure. The average eddy current loss is 0.98mW, which is 69.2% lower than that of the traditional structure, and the average hysteresis loss is 3.74mW, which is 59.2% lower than that of the traditional structure. This is because the cancellation of the armature magnetic field reduces the change in magnetic flux density in the yoke, thereby reducing core loss and improving the energy efficiency of the motor.

[0049] In addition, to further verify the technical advantage of the present invention that it does not require thickening of the iron core, such as... Figure 13 As shown, a parametric scanning test was performed on the thickness of the third yoke 3, i.e., the intermediate iron core. The test parameters were set as follows: the initial value of the iron core thickness was 5 mm, the end value was 15 mm, and the test step size was 1 mm. Other structural parameters and test conditions remained unchanged throughout the test. The test results showed that the overall thrust of the motor did not change significantly with the increase of the iron core thickness. This fully demonstrates that the technical solution of the present invention, which suppresses magnetic saturation by offsetting the armature magnetic field, does not require increasing the cross-sectional area of ​​the iron core or thickening the iron core to avoid magnetic saturation. It can ensure the rated thrust and linear thrust performance of the motor, and effectively reduce the size of the motor, further optimizing the compactness of the motor structure and adapting to high-precision, small-volume precision drive application scenarios.

Claims

1. A voice coil motor with an iron core that suppresses the effects of magnetic saturation and armature reaction, characterized in that: It includes a stator assembly and a rotor assembly; the stator assembly includes a yoke structure and a permanent magnet structure; the yoke structure includes multiple segments of magnetic conductive members, and the multiple segments of magnetic conductive members as a whole form a symmetrically closed magnetic circuit structure; the permanent magnet structure is divided into a first magnetic group and a second magnetic group, and the two magnetic groups are symmetrically arranged in the internal cavity of the yoke structure, and the overall magnetization directions of the first magnetic group and the second magnetic group are symmetrically arranged in the opposite direction; the rotor assembly includes a first coil winding, a second coil winding and an insulating support skeleton, the first coil winding and the second coil winding are both fixedly installed on the insulating support skeleton, the first coil winding extends into the air gap between the first magnetic group and the yoke structure, and the second coil winding extends into the air gap between the second magnetic group and the yoke structure; the electrical parameters and structural dimensions of the first coil winding and the second coil winding are exactly the same, and equal and opposite currents are passed through the first coil winding and the second coil winding during operation.

2. The iron-core voice coil motor for suppressing magnetic saturation and armature reaction according to claim 1, characterized in that, The multiple segments of magnetic conductive members include a first yoke, a second yoke and a third yoke, the first yoke is the left and right end covers, the second yoke is the upper and lower back plates, the third yoke is the middle iron core, and the first yoke, the second yoke and the third yoke together form a symmetrically closed magnetic circuit structure in the shape of "曰".

3. The iron-core voice coil motor for suppressing the effects of magnetic saturation and armature reaction according to claim 2, characterized in that, The first magnetic group is fixedly installed in the cavity between the left first yoke and the third yoke, and includes a first permanent magnet and a second permanent magnet symmetrically arranged in the vertical direction; the magnetization direction of the first permanent magnet is vertically downward, and the magnetization direction of the second permanent magnet is vertically upward.

4. The iron-core voice coil motor for suppressing the effects of magnetic saturation and armature reaction according to claim 2, characterized in that, The second magnetic group is fixedly installed in the cavity between the right first yoke and the third yoke, and includes a third permanent magnet and a fourth permanent magnet symmetrically arranged in the vertical direction; the magnetization direction of the third permanent magnet is vertically upward, and the magnetization direction of the fourth permanent magnet is vertically downward.

5. The iron-core voice coil motor for suppressing the effects of magnetic saturation and armature reaction according to claim 1, characterized in that, The first coil winding is coil winding A, the second coil winding is coil winding B, and the insulating support skeleton is a coil skeleton; coil winding A is fitted and installed in the air gap between the first magnetic group and the third yoke, and coil winding B is fitted and installed in the air gap between the second magnetic group and the third yoke, and the two coil windings are coaxially symmetrically arranged.

6. The iron-core voice coil motor for suppressing the effects of magnetic saturation and armature reaction according to claim 1, characterized in that, The first yoke, the second yoke and the third yoke are all made of magnetic conductive materials.

7. The iron-core voice coil motor for suppressing the effects of magnetic saturation and armature reaction according to claim 1, characterized in that, The coil skeleton is made of non-magnetic conductive materials.

8. The iron-core voice coil motor for suppressing the effects of magnetic saturation and armature reaction according to claim 1, characterized in that, Both coil winding A and coil winding B are made of copper wires wound.

9. The iron-core voice coil motor for suppressing the effects of magnetic saturation and armature reaction according to claim 1, characterized in that, The thickness of the third yoke ranges from 5 mm to 15 mm.

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