CN115473385A - Anti-shaft-jump precise magnetic encoder and motor - Google Patents

Anti-shaft-jump precise magnetic encoder and motor Download PDF

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Publication number
CN115473385A
CN115473385A CN202211132041.7A CN202211132041A CN115473385A CN 115473385 A CN115473385 A CN 115473385A CN 202211132041 A CN202211132041 A CN 202211132041A CN 115473385 A CN115473385 A CN 115473385A
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China
Prior art keywords
magnet
shaft
magnetic encoder
pole
sensor
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CN202211132041.7A
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Chinese (zh)
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高森
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Suzhou Weishili Technology Co ltd
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Beijing Xinshijie Intelligent Technology Co ltd
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Priority to CN202211132041.7A priority Critical patent/CN115473385A/en
Publication of CN115473385A publication Critical patent/CN115473385A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/20—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for measuring, monitoring, testing, protecting or switching
    • H02K11/21—Devices for sensing speed or position, or actuated thereby
    • H02K11/215—Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)

Abstract

The invention discloses a shaft jump resistant precision magnetic encoder and a motor, which comprise a magnet and a circuit board, wherein the circuit board is provided with a magnetic sensor, and the shaft jump resistant precision magnetic encoder is characterized in that: the magnet is cylindrical structure, the positive center of magnet is equipped with a T magnet, the both sides of T magnet are N utmost point magnet and the S utmost point magnet that the symmetry set up respectively, N utmost point magnet and S utmost point magnet along the axial direction of magnet magnetizes, T magnet orientation N utmost point magnet or S utmost point magnet direction magnetize. The invention improves the precision of the magnetic encoder and solves the problem of low precision of the magnetic encoder caused by the eccentricity of a motor shaft, shaft run-out and bearing seat clearance in the prior art.

Description

Anti-shaft-jump precise magnetic encoder and motor
Technical Field
The invention relates to the field of encoders, in particular to a shaft jump resistant precision magnetic encoder and a motor.
Background
The magnetic encoder can be applied to detecting the magnetic field position of the motor rotor, providing accurate motor speed and position signals, outputting the signals to the driver for analysis, comparison and logic judgment, and finally driving the motor. The magnetic encoder is a sensor which provides an accurate signal for the driver at any moment so that the driver can make accurate analysis and judgment.
The magnetic encoder mainly comprises a magnet, a circuit board and a magnetic sensor arranged on the circuit board, wherein the magnet is arranged on a motor shaft of a motor rotor, the circuit board is arranged behind a motor stator through a support, and a distance is reserved between the circuit board and the magnet. The magnetic sensor includes an AMR sensor and a TMR sensor.
Taking the installation of the motor and the components as an ideal state and the rotation of the motor shaft as an example, as shown in fig. 1, the AMR sensor always faces the point E of the magnet (the point E is the center of the magnet, and the two sides are the N pole and the S pole respectively), but in practical application, the motor shaft has a gap and an eccentricity, as shown in fig. 2, the actual center point changes from the original point E to the point F (the point F is beside the point E and not in the center of the magnet), so that when the motor rotates, the point F will be rotated as the center, the AMR sensor will not always face the point E, and as the angle rotates, the AMR sensor will face the point E1 (the point E1 is beside the point E and the point F, and the point E1 is not in the center of the magnet), therefore, compared with the ideal state of fig. 1, the magnetic field at the point E and the magnetic field at the point E1 will obviously change. Due to the change of the magnetic field, a corresponding detailed fluctuation of the speed is caused. Referring to fig. 3, the parallelism of the magnetic field received by the magnetic sensor is not good, so that the parallelism of the magnetic field received by the magnetic sensor is not good, which results in poor detection accuracy. Therefore, the accuracy of the magnetic encoder is poor due to the shaft center run-out of the motor shaft and the bearing pitch. Therefore, the technical problem is solved by the skilled person in the art.
Disclosure of Invention
The invention aims to provide a high-precision magnetic encoder resisting shaft jump and a motor.
In order to achieve the purpose, the invention adopts the technical scheme that: the utility model provides an anti axle jumping precision magnetic encoder, includes magnet and circuit board, be equipped with magnetic sensor on the circuit board, magnet is cylindrical structure, the positive center of magnet is equipped with a T magnet, the both sides of T magnet are N utmost point magnet and the S utmost point magnet that the symmetry set up respectively, N utmost point magnet and S utmost point magnet along the axial direction of magnet magnetizes, T magnet orientation N utmost point magnet or S utmost point magnet direction magnetize.
The middle parts of the inner sides of the N-pole magnet and the S-pole magnet are respectively connected with the outer surface of the T-pole magnet, and the two ends of the inner side of the N-pole magnet are respectively connected with the two ends of the inner side of the S-pole magnet.
In the technical scheme, the N-pole magnet and the S-pole magnet are opposite in magnetizing direction.
In the above technical solution, the magnetizing direction of the T-pole magnet is perpendicular to the magnetizing direction of the N-pole magnet or the S-pole magnet.
In the technical scheme, two axial ends of the magnet are respectively a first end face and a second end face, the first end face is connected with a motor shaft through a support, the magnet and the rotating shaft are coaxially arranged, the circuit board is arranged on one side of the second end face of the magnet, and a space is arranged between the circuit board and the second end face of the magnet; the magnetic sensor includes a set of AMR sensor and two sets of TMR sensors at least, AMR sensor install in the positive center of circuit board, just AMR sensor is just right the positive center of magnet second terminal surface sets up, the multiunit TMR sensor set up in the AMR sensor side on the circuit board, just TMR sensor is just right the second terminal surface setting of magnet.
In the above technical solution, the AMR sensor is disposed opposite to the T magnet.
In the technical scheme, the thickness of the T magnet is equal to the thickness of the N-pole magnet and the S-pole magnet; the width of the T magnet is M, and the length of the T magnet is L;
said R + a < M <2 (R + a);
the 2 × M yarn-woven fabric (L yarn-woven fabrics) R0-2*a-R1;
wherein a is the maximum eccentric runout of the motor shaft;
r0 is the outer diameter of the magnet;
r is the outer diameter of an effective sensing area of the AMR sensor;
and R1 is the outer diameter of an effective sensing area of the TMR sensor.
In the technical scheme, the cross section of the T magnet is rectangular, square, oval or polygonal in a symmetrical structure.
In order to achieve the purpose, the invention adopts a motor which comprises a motor shaft and the anti-shaft-jump precise magnetic encoder, wherein the magnet is driven to rotate by the motor shaft.
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:
1. the laterally magnetized T-shaped magnet is arranged in the middle of the magnet, compared with the prior structure, the magnetic field parallelism can be effectively improved, the magnetic field density above the center of the magnet is higher, the magnetic field parallelism and strength received by the magnetic sensor are improved, the precision can be improved, the detection precision of the magnetic encoder is improved, the problem of precision reduction caused by shaft jumping and bearing clearance can be solved, and the encoding precision is ensured.
Drawings
FIG. 1 is a schematic diagram of a prior art AMR sensor at a point E opposite to a magnet;
FIG. 2 is a schematic diagram of a prior art AMR sensor at a point opposite to a magnet E1;
FIG. 3 is a schematic diagram of a magnetic field configuration of a magnet in a prior art with an AMR sensor facing a point E1 of the magnet;
FIG. 4 is a schematic diagram of two signals of an AMR sensor and signals of a TMR sensor and magnet angles in the present invention;
FIG. 5 is a schematic view of a magnet and a circuit board of a magnetic encoder according to an embodiment of the present invention (the cross section of the T-shaped magnet is a square structure);
FIG. 6 is a schematic structural diagram illustrating a magnetizing direction of a magnet in a magnetic encoder according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a magnetic field structure when the AMR sensor of the magnetic encoder is aligned with the point E1 of the magnet according to the first embodiment of the present invention;
FIG. 8 is a schematic diagram of an end face structure of a magnet in a magnetic encoder according to an embodiment of the present invention (the cross section of the T magnet is a polygonal structure);
FIG. 9 is a schematic diagram of an end face structure of a magnet in a magnetic encoder according to an embodiment of the present invention (the cross section of the T magnet has an elliptical structure);
FIG. 10 is a schematic diagram of a motor according to an embodiment of the present invention.
Wherein: 1. a magnet; 2. a circuit board; 3. a T magnet; 4. an N-pole magnet; 5. an S-pole magnet; 6. a first end face; 7. a second end face; 8. a support; 9. a motor shaft; 10. an AMR sensor; 11. a TMR sensor; 12. an electric motor.
Detailed Description
The invention is further described with reference to the following figures and examples:
in a magnetic encoder (the magnet has only an S-pole magnet and an N-pole magnet), the AMR sensor is mainly responsible for converting 0 ° to 360 ° of the magnet angle θ into sine and cosine information sin (2 × θ) and cos (2 × θ), as shown in fig. 4.
Therefore, two paths of signals of the AMR sensor enter the MCU of the circuit board, and digital quantity is divided:
sin(2*θ)/cos(2*θ)＝tan(2*θ)＝a；
then, the result is arctangent again: arctan (a) =2 × θ.
However, since 2 × θ is obtained, it is impossible to distinguish between 0-180 degrees and 180-360 degrees, and the TMR sensor is introduced, and each time the magnet rotates, a jump edge is generated at the boundary of the S pole magnet and the N pole magnet opposite to the TMR sensor, and signals generated by two sets of TMR sensors are shown in fig. 4, then, there are 4 states according to the 0,1 state of the TMR sensor output signal: (1,0), (1,1), (0,1), (0,0); when the states are (1,0) and (1,1), the mechanical angle is 0-180 degrees, and when the states are (0,1) and (0,0), the mechanical angle is 180-360 degrees, so that the magnet can be matched with an AMR sensor and a TMR sensor to accurately analyze the mechanical angle.
The first embodiment is as follows: referring to fig. 5 to 10, the anti-shaft-jump precise magnetic encoder comprises a magnet 1 and a circuit board 2, wherein a magnetic sensor is arranged on the circuit board, the magnet is of a cylindrical structure, a T magnet 3 is arranged in the center of the magnet, N-pole magnets 4 and S-pole magnets 5 are symmetrically arranged on two sides of the T magnet respectively, the N-pole magnets and the S-pole magnets are magnetized along the axial direction of the magnet, and the T magnet is magnetized towards the N-pole magnets or the S-pole magnets.
Referring to fig. 5, 6, 8 and 9, the inner middle portions of the N-pole magnet and the S-pole magnet are respectively connected to the outer surface of the T-pole magnet, and the inner two ends of the N-pole magnet are respectively connected to the inner two ends of the S-pole magnet. Compared with the conventional cylindrical magnet, in the conventional structure in which the N-pole magnet and the S-pole magnet are symmetrically arranged, in the present embodiment, a through groove is formed in the center of the magnet, the T-magnet is mounted in the through groove, and the outer wall of the T-magnet is connected to the inner walls of the N-pole magnet and the S-pole magnet.
And the magnetizing directions of the N-pole magnet and the S-pole magnet are opposite.
The magnetizing direction of the T magnet is perpendicular to the magnetizing direction of the N-pole magnet or the S-pole magnet.
In the present embodiment, the magnetizing direction of the T magnet is set toward the N-pole magnet.
Referring to fig. 6 and 10, two axial ends of the magnet are respectively a first end surface 6 and a second end surface 7, the first end surface is connected with a motor shaft 9 through a bracket 8, the magnet is coaxially arranged with the rotating shaft, the circuit board is arranged on one side of the second end surface of the magnet, and a gap is arranged between the circuit board and the second end surface of the magnet; magnetic sensor includes a set of AMR sensor 10 and two sets of TMR sensor 11, the AMR sensor install in the positive center of circuit board, just the AMR sensor is just right the positive center of magnet second terminal surface sets up, the multiunit TMR sensor set up in the AMR sensor side on the circuit board, just the TMR sensor is just right the second terminal surface of magnet sets up.
The AMR sensor is arranged right opposite to the T magnet.
The principle of how to resolve the mechanical angle by using the magnet, the AMR sensor and the TMR sensor is described in the above, and when the motor shaft is eccentric, the AMR sensor can be always right against the T magnet, so that the parallelism of the magnetic field is obviously improved in the magnetic field direction, and the density of the magnetic field between the second end surface of the magnet and the circuit board is improved, so that the precision of the magnetic encoder can be improved, and the precision of the magnetic encoder is ensured.
Wherein the thickness of the T magnet is equal to the thickness of the N-pole magnet and the S-pole magnet; the width of the T magnet is M, and the length of the T magnet is L;
said R + a < M <2 (R + a);
the 2 × M and N < -L < -R0-2*a-R1;
wherein a is the maximum eccentric runout of the motor shaft;
r0 is the outer diameter of the magnet;
r is the outer diameter of an effective sensing area of the AMR sensor;
and R1 is the outer diameter of an effective sensing area of the TMR sensor.
In this embodiment, the magnetizing direction of the N-pole magnet is toward the second end surface of the magnet, i.e., toward the circuit board, and the magnetizing direction of the S-pole magnet is toward the first end surface, i.e., away from the circuit board. Since the magnetization direction of the N-pole magnet is oriented toward the AMR sensor, the magnetization direction of the T-magnet is oriented toward the N-pole magnet, so that the magnetic field density between the magnet and the circuit board is higher and the parallelism of the magnetic field is better, as shown in fig. 7. That is, the magnet constitutes a parallel magnetic field generator for improving the parallelism of the magnetic field and the magnetic field density, and improving the accuracy of the magnetic encoder.
Through the precise design of the size of the T magnet, the AMR sensor can be ensured to face the T magnet, and meanwhile, the magnetic field density is ensured to be high, the parallelism is good, and the precision of the magnetic encoder is ensured to be high.
In this embodiment, the cross section of the T-shaped magnet is a rectangle, a square, an ellipse or a polygon with a symmetrical structure. The N-pole magnet and the S-pole magnet are respectively and symmetrically arranged on two sides of the center of the magnet, and the T-shaped magnet is arranged between the N-pole magnet and the S-pole magnet and symmetrically arranged along the connecting line of the N-pole magnet and the S-pole magnet.
In order to achieve the purpose, the invention adopts a motor 12 which comprises a motor shaft and the shaft jump resistant precision magnetic encoder, wherein the magnet is driven to rotate by the motor shaft.

Claims (9)

1. The utility model provides an anti axle jumping precision magnetic encoder, includes magnet and circuit board, be equipped with magnetic sensor on the circuit board, its characterized in that: magnet is cylindrical structure, the positive center of magnet is equipped with a T magnet, the both sides of T magnet are N utmost point magnet and the S utmost point magnet that the symmetry set up respectively, N utmost point magnet and S utmost point magnet along the axial direction of magnet magnetizes, T magnet orientation N utmost point magnet or S utmost point magnet direction magnetize.
2. The anti-shaft-jump precision magnetic encoder according to claim 1, characterized in that: the middle parts of the inner sides of the N-pole magnet and the S-pole magnet are respectively connected with the outer surface of the T-pole magnet, and the two ends of the inner side of the N-pole magnet are respectively connected with the two ends of the inner side of the S-pole magnet.
3. The anti-shaft-jump precision magnetic encoder according to claim 1, characterized in that: and the magnetizing directions of the N-pole magnet and the S-pole magnet are opposite.
4. The anti-shaft-jump precision magnetic encoder according to claim 1, characterized in that: the magnetizing direction of the T magnet is perpendicular to the magnetizing direction of the N-pole magnet or the S-pole magnet.
5. The anti-shaft-jump precision magnetic encoder according to claim 1, characterized in that: the axial two ends of the magnet are respectively a first end face and a second end face, the first end face is connected with a motor shaft through a support, the magnet and the rotating shaft are coaxially arranged, the circuit board is arranged on one side of the second end face of the magnet, and a space is arranged between the circuit board and the second end face of the magnet; the magnetic sensor includes a set of AMR sensor and two sets of TMR sensors at least, AMR sensor install in the positive center of circuit board, just AMR sensor is just right the positive center of magnet second terminal surface sets up, the multiunit TMR sensor set up in the AMR sensor side on the circuit board, just TMR sensor is just right the second terminal surface setting of magnet.
6. The shaft-jump resistant precision magnetic encoder according to claim 5, characterized in that: the AMR sensor is arranged right opposite to the T magnet.
7. The anti-shaft-jump precision magnetic encoder according to claim 5, characterized in that: the thickness of the T magnet is equal to that of the N-pole magnet and the S-pole magnet; the width of the T magnet is M, and the length of the T magnet is L;
said R + a < M <2 (R + a);
the 2 × M yarn-woven fabric (L yarn-woven fabrics) R0-2*a-R1;
wherein a is the maximum eccentric runout of the motor shaft;
r0 is the outer diameter of the magnet;
r is the outer diameter of an effective sensing area of the AMR sensor;
and R1 is the outer diameter of an effective sensing area of the TMR sensor.
8. The shaft-jump resistant precision magnetic encoder according to claim 1, characterized in that: the cross section of the T magnet is rectangular, square, oval or polygonal in a symmetrical structure.
9. An electric machine, includes the motor shaft, its characterized in that: comprising a shaft jump resistant precision magnetic encoder according to any of claims 1-8, said magnet being driven in rotation by said motor shaft.
CN202211132041.7A 2022-09-16 2022-09-16 Anti-shaft-jump precise magnetic encoder and motor Pending CN115473385A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211132041.7A CN115473385A (en) 2022-09-16 2022-09-16 Anti-shaft-jump precise magnetic encoder and motor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211132041.7A CN115473385A (en) 2022-09-16 2022-09-16 Anti-shaft-jump precise magnetic encoder and motor

Publications (1)

Publication Number Publication Date
CN115473385A true CN115473385A (en) 2022-12-13

Family

ID=84333732

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211132041.7A Pending CN115473385A (en) 2022-09-16 2022-09-16 Anti-shaft-jump precise magnetic encoder and motor

Country Status (1)

Country Link
CN (1) CN115473385A (en)

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Effective date of registration: 20230419

Address after: Room 1712, 17th floor, Phoenix Plaza, 66 Dongwu North Road, Wuzhong District, Suzhou, Jiangsu 215000

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