Magnet for a sensor and method of magnetizing the same

Abstract

The application relates to the technical field of magnetic sensors, and specifically provides a magnet for a sensor and a magnetization method thereof, the magnet comprising: the magnet is in a circular-arc tile structure, and the length of the magnet is equal to or greater than the maximum displacement stroke capable of being detected by the sensor; the magnetization direction of the magnet adopts one of the length, thickness or circular-arc radial direction of the magnet. The magnetization method comprises the following steps: selecting the material of the magnet and determining the size of the magnet according to the maximum displacement stroke capable of being detected by the sensor, and manufacturing a magnet block in a circular-arc tile structure; determining the magnetization direction of the magnet according to the relationship between the magnetic induction intensity of the sensor and the rotary displacement position and the rotary angle based on the Hall effect; the magnetization direction adopts one of the length, thickness or circular-arc radial direction of the magnet; calculating the magnetization data of the magnet; and magnetizing the magnet block according to the magnetization direction and the magnetization data to obtain the magnet for the sensor. The application can improve the rotary displacement measurement precision of the sensor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic sensor, in particular to a magnet for sensor and a magnetizing method thereof. BACKGROUND

[0002] The property of a magnet attracting iron, cobalt, nickel and other substances is called magnetism. The region with strong magnetism at both ends of a magnet is called a magnetic pole, one end being the north pole (N pole) and the other end being the south pole (S pole). Like poles repel each other, and unlike poles attract each other. A magnet is needed in a magnetic sensor for measuring the position of displacement.

[0003] At present, the magnet used in a magnetic sensor for measuring the position of displacement is usually cylindrical or rectangular in structure. The principle is to convert the magnetic induction intensity perpendicular to the axis of the magnet into a corresponding magnet position signal by using the corresponding relationship between the size of the magnetic induction intensity perpendicular to the axis of the magnet and the position of the magnet.

[0004] The cylindrical or rectangular magnet structure is suitable for linear displacement position detection, but when the magnet of this structure is used for rotary displacement position detection, the displacement position to be detected no longer coincides with the axis of the magnet, resulting in a decrease in the magnetic induction intensity near the two ends of the displacement stroke. In order to ensure sufficient accuracy and detectability, it is necessary to increase the volume of the magnet or use better magnet materials, thereby increasing the cost of the product. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a magnet for sensor, comprising: the magnet is in a circular arc tile structure, the length of the magnet is equal to or greater than the maximum displacement stroke that can be detected by the sensor;

[0006] The magnetization direction of the magnet is in one of the following directions: along the length, thickness or radius of the circular arc of the magnet.

[0007] Optionally, the magnet is provided with an asymmetric foolproof structure on the inner arc wall, the outer arc wall, the two ends in the length direction or the upper and lower end faces in the thickness direction.

[0008] Optionally, the magnet comprises rare earth metal neodymium, rare earth metal praseodymium, pure iron, aluminum and boron iron alloy material, and is made through the following procedures: batching, smelting ingot, powder making, molding, sintering and tempering, magnetic detection, grinding, pin cutting, electroplating, magnetization and finished product.

[0009] Among them, the smelting furnace is used for smelting ingot; the crusher is used for crushing first, and the ball mill or air flow mill is used for grinding; the press forming machine or isostatic press is used for molding; the sintering furnace and heat treatment vacuum furnace are used for sintering and tempering; the magnetic property tester and gauss meter are used for magnetic detection.

[0010] The application further provides a magnetization method of a magnet for a sensor, comprising:

[0011] The material of the magnet is selected and the size of the magnet is determined according to the maximum displacement stroke that can be detected by the sensor, and the magnet block in the circular-arc tile structure is manufactured;

[0012] The magnetization direction of the magnet is determined according to the relationship between the magnetic induction intensity of the sensor and the rotary displacement position and the rotary angle based on the Hall effect, and the magnetization direction is along one of the length, thickness or circular-arc diameter of the magnet;

[0013] The magnetization data of the magnet is calculated, and the magnet block is magnetized according to the magnetization direction and the magnetization data to obtain the magnet for the sensor.

[0014] Optionally, when the magnet block in the circular-arc tile structure is manufactured, the asymmetric foolproof structure is arranged on the arc-shaped inner wall, the arc-shaped outer wall, the length direction end or the thickness direction upper and lower end surface of the magnet block.

[0015] Optionally, if the magnetization direction is along the length direction of the magnet, the calculation of the magnetization data is determined by the following conditions:

[0016] According to the magnetic induction intensity distribution of the sensor, the Z-axis magnetic induction intensity perpendicular to the rotary displacement stroke has a substantially linear relationship with the rotary position of the magnet, the magnet of the sensor based on the Hall effect detects the rotary displacement position and the rotary angle by measuring the Z-axis magnetic induction intensity according to the relationship between the Z-axis magnetic induction intensity and the rotary displacement position and the rotary angle, or performs the arctangent operation on any two components of the X-axis magnetic induction intensity, the Y-axis magnetic induction intensity and the Z-axis magnetic induction intensity.

[0017] Optionally, if the magnetization direction is along the thickness direction or the circular-arc diameter direction of the magnet, the calculation of the magnetization data is determined by the following conditions:

[0018] According to the magnetic induction intensity distribution of the sensor, the arctangent operation is performed on any two components of the X-axis magnetic induction intensity, the Y-axis magnetic induction intensity and the Z-axis magnetic induction intensity.

[0019] Optionally, the magnetization processing is performed by using a pulse magnetic field that is suitable for the magnetization direction and the magnetization data of the magnet, and the pulse magnetic field is realized by using a pulse current of the magnetization device.

[0020] Optionally, the magnetization device is provided with a power input control circuit for controlling the pulse current for magnetization during the magnetization processing.

[0021] The power input control circuit comprises a current-limiting adjustment module, a field effect transistor Q1, a reference voltage module, an amplifier U1, an error amplifier U2, variable resistors R1, R2 and R3.

[0022] The input end of the current-limiting adjustment module is connected with the power supply, and the output end of the current-limiting adjustment module is connected with the source electrode of the field effect tube Q1;

[0023] The control end of the current-limiting adjustment module is connected with the pin 4 of the error amplifier U2, the input pin 1 of the error amplifier U2 is connected with the output pin 4 of the amplifier U1 through the variable resistor R1, the pin 3 of the error amplifier U2 is respectively connected with the reference voltage module and the pin 3 of the amplifier U1, and the output pin 5 of the error amplifier U2 is connected with the gate electrode of the field effect tube Q1;

[0024] The input pin 1 of the amplifier U1 is connected with the reference voltage module, the input pin 2 of the amplifier U1 is respectively connected with one end of the variable resistor R2 and one end of the variable resistor R3, the other end of the variable resistor R2 is connected with the input pin 1 of the error amplifier U2, and the other end of the variable resistor R3 is grounded;

[0025] The input pin 2 of the error amplifier U2 is connected with the drain electrode of the field effect tube Q1 as an output end.

[0026] Optionally, during the magnetization process, the pulse current of the magnetization device is detected in real time, and a self-adaptive filter is used to filter the detection signal.

[0027] The magnet for a sensor and the magnetization method thereof can ensure that the magnetic sensor adopting the magnet has higher precision, higher sensitivity and better detectability in rotary displacement measurement without increasing the volume of the magnet or using better magnet materials.

[0028] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

[0029] The technical solutions of the present application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 This is a three-dimensional schematic diagram of a magnet used in a sensor according to an embodiment of the present invention;

[0032] Figure 2 This is a three-dimensional schematic diagram of an embodiment of the present invention in which the magnet for a sensor adopts the length direction as the magnetization direction;

[0033] Figure 3 This is a perspective schematic diagram of an embodiment of the present invention in which the magnet for a sensor adopts the thickness direction as the magnetization direction;

[0034] Figure 4 This is a three-dimensional schematic diagram of an embodiment of the present invention in which the magnet for a sensor adopts the arc radial direction as the magnetization direction;

[0035] Figure 5 This is a flow chart of a magnetization method for a sensor according to an embodiment of the present invention;

[0036] Figure 6 A schematic diagram of a power input control circuit configured for a magnetizing device useful in a magnetizing method for a sensor according to an embodiment of the present invention;

[0037] Figure 7 The magnet for the sensor of the present invention Figure 2 A schematic diagram of magnetic induction intensity distribution in an embodiment;

[0038] Figure 8 The magnet for the sensor of the present invention Figure 3 A schematic diagram of magnetic induction intensity distribution in an embodiment;

[0039] Figure 9 The magnet for the sensor of the present invention Figure 4 A schematic diagram of magnetic induction intensity distribution in an embodiment;

[0040] Figure 10 A diagram showing the relative positions of the magnet for the sensor of the present invention at the initial position (i.e., 0 degrees) in the sensor and the Hall chip;

[0041] Figure 11 This is a diagram showing the relative position of the magnet used for the sensor of the present invention and the Hall chip after being applied to the sensor and rotated 45 degrees. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present application are described below with reference to the accompanying drawings, and it should be understood that the preferred embodiments described herein are only used to explain and illustrate the present application, and are not used to limit the present application.

[0043] As shown in Figures 1-4 , the present application provides a magnet for a sensor, comprising: a magnet 1 in a circular arc tile structure, the length of the magnet 1 is equal to or greater than the maximum displacement stroke 2 that the sensor can detect;

[0044] The magnetization direction of the magnet 1 is in one of the length, thickness or circular arc radial direction of the magnet 1; Figures 2-4 The magnetization direction is indicated by an arrow.

[0045] The working principle and beneficial effects of the above technical solution are: the magnet of the magnetic sensor for displacement measurement in the present application is made into a circular arc tile structure, the shape of the magnet coincides with the stroke of the rotational displacement, the length of the magnet is equal to or greater than the maximum displacement stroke that the sensor can detect, and the magnetization direction of the circular arc tile magnet can be selected as one of the length, thickness or circular arc radial direction; the present application can ensure that the magnetic sensor using the magnet has higher precision, higher sensitivity and better detectability in rotational displacement measurement without increasing the volume of the magnet in a cylindrical or rectangular structure or using better magnet material; wherein the length of the magnet refers to the arc length of the median circular arc in the radial direction of the magnet; since the shape of the magnet coincides with the stroke of the displacement, a better magnetic field distribution is obtained than the cylindrical and rectangular magnets.

[0046] In one embodiment, as shown in Figures 1-4 , the magnet 1 is provided with an asymmetric foolproof structure 3 on the arc-shaped inner wall, the arc-shaped outer wall, the length direction both ends or the upper and lower end faces in the thickness direction; as shown in Figure 1 , the foolproof structure 3 is a semi-cylindrical notch, which is arranged at the length direction of the arc-shaped inner wall, and can be used for the identification of the north-south poles when the magnetization direction is along the length or the circular arc radial direction of the magnet.

[0047] The working principle and beneficial effects of the above technical solution are: the present application sets the asymmetric foolproof structure on the arc-shaped inner wall, the arc-shaped outer wall, the length direction both ends or the upper and lower end faces in the thickness direction of the magnet, which can improve the identification of the north-south poles of the magnet, facilitate the identification and installation of the magnet during the manufacturing of the magnetic sensor, avoid assembly errors, improve the production and assembly efficiency of the magnetic sensor, and reduce the rework rate, thereby reducing the production cost; wherein the length direction actually refers to the arc direction of the circular arc shape of the magnet, and some foolproof structures are adopted on the inner wall or the outer wall or both ends of the arc shape to prevent the identification of the north-south poles of the magnet during assembly by using the asymmetry of the structure.

[0048] In one embodiment, the magnet comprises rare earth metal neodymium, rare earth metal praseodymium, pure iron, aluminum and boron iron alloy material, and is made through the following procedures: batching, smelting ingot, powdering, molding, sintering and tempering, magnetic detection, grinding processing, pin cutting processing, electroplating, magnetization and finished product;

[0049] The smelting furnace is used for smelting ingot, the crusher is used for crushing, and then the ball mill or the airflow mill is used for grinding; the molding machine or the isostatic press is used for molding; the sintering furnace and the heat treatment vacuum furnace are used for sintering and tempering; the magnetic property tester and the gauss meter are used for magnetic detection.

[0050] The working principle and beneficial effects of the technical scheme are as follows: the magnet is made of rare earth metal neodymium, rare earth metal praseodymium, pure iron, aluminum and boron iron alloy material, so that the magnetic induction intensity of the magnet can be further improved, and the sensitivity of the magnetic sensor using the magnet can be improved; for magnet manufacturing, the materials are sequentially subjected to batching, smelting ingot, powdering, molding, sintering and tempering to form a magnet block with a circular arc tile structure, and then the magnet block is subjected to magnetic detection, grinding processing, pin cutting processing, electroplating and magnetization to obtain a finished magnet, the smelting furnace can accurately control the smelting temperature, and the fusion degree of different materials can be improved, so that the quality of the magnet is enhanced; the crusher is used for crushing, and then the ball mill or the airflow mill is used for grinding, so that finer material powder can be made, and cracks can be avoided during subsequent molding; the molding machine or the isostatic press is used for molding, so that the pressure value can be better controlled, and the molding quality can be improved; the sintering furnace and the heat treatment vacuum furnace are used for sintering and tempering, so that the internal stress of the magnet block can be eliminated, the stability of the structure of the magnet block can be improved, and the service life of the magnet can be improved; the magnetic property tester and the gauss meter are used for magnetic detection, so that the quality of the magnet block can be guaranteed, and the magnetization effect and the production efficiency can be improved.

[0051] As shown in Figure 5 The magnetization method for the magnet for the sensor provided by the embodiment of the present application comprises the following steps:

[0052] S100: selecting a magnet material according to the maximum displacement stroke that can be detected by the sensor and determining the size of the magnet, and making a magnet block with a circular arc tile structure;

[0053] S200: determining the magnetization direction of the magnet according to the relationship between the magnetic induction intensity of the sensor and the rotary displacement position and the rotary angle based on the Hall effect; the magnetization direction is along one of the length, the thickness or the circular arc diameter of the magnet;

[0054] S300: calculating the magnetization data of the magnet; and magnetizing the magnet block according to the magnetization direction and the magnetization data to obtain the magnet for the sensor.

[0055] The working principle and beneficial effects of the technical solution are as follows: the magnet of the displacement measurement magnetic sensor is made into a circular-arc tile structure, the shape of the magnet coincides with the stroke of the rotary displacement, the length of the magnet is equal to or greater than the maximum displacement stroke that the sensor can detect, the magnetization direction of the circular-arc tile magnet can be selected as one of the length, thickness or circular-arc diameter; the magnet of the present application can ensure that the magnetic sensor using the magnet has higher precision, higher sensitivity and better detectability in rotary displacement measurement without increasing the volume of the cylindrical or rectangular magnet or using better magnet materials; wherein the length of the magnet refers to the arc length of the median circular arc in the radial direction of the magnet; since the shape of the magnet coincides with the stroke of the displacement, a better magnetic field distribution is obtained than the cylindrical and rectangular magnets.

[0056] In one embodiment, in the step S100, when the magnet block of the circular-arc tile structure is made, the asymmetric foolproof structure is arranged on the arc-shaped inner wall, the arc-shaped outer wall, the length direction both ends or the upper and lower end faces in the thickness direction of the magnet block.

[0057] The working principle and beneficial effects of the technical solution are as follows: the magnet of the displacement measurement magnetic sensor is made into a circular-arc tile structure, the shape of the magnet coincides with the stroke of the rotary displacement, the length of the magnet is equal to or greater than the maximum displacement stroke that the sensor can detect, the magnetization direction of the circular-arc tile magnet can be selected as one of the length, thickness or circular-arc diameter; the magnet of the present application can ensure that the magnetic sensor using the magnet has higher precision, higher sensitivity and better detectability in rotary displacement measurement without increasing the volume of the cylindrical or rectangular magnet or using better magnet materials; wherein the length of the magnet refers to the arc length of the median circular arc in the radial direction of the magnet; since the shape of the magnet coincides with the stroke of the displacement, a better magnetic field distribution is obtained than the cylindrical and rectangular magnets.

[0058] In one embodiment, in the step S300, if the magnetization direction is along the length direction of the magnet, the calculation of the magnetization data is determined by the following conditions:

[0059] According to the magnetic induction intensity distribution of the sensor, the magnetic induction intensity distribution is as shown in Figure 7 The Z-axis magnetic induction intensity has a substantially linear relationship with the rotary position of the magnet, the magnet of the sensor based on the Hall effect detects the rotary displacement position and the rotary angle by measuring the Z-axis magnetic induction intensity according to the relationship between the Z-axis magnetic induction intensity and the rotary displacement position and the rotary angle; or the arctangent operation is performed on any two components of the X-axis magnetic induction intensity, the Y-axis magnetic induction intensity and the Z-axis magnetic induction intensity.

[0060] The working principle and beneficial effects of the above technical solution are: the present solution provides a magnetization data determination method along the length direction as the magnetization direction, which adapts to the characteristics of the magnetization direction, so as to better implement the magnetization process, guarantee the magnetization quality, and improve the magnet yield; when magnetized along the length direction, the magnetic induction strength perpendicular to the displacement stroke has good linearity in the entire formation range, which can be used for the design of linear magnetic sensors and the design of three-axis angle sensors; the value of the arctangent operation has a one-to-one correspondence with the rotary displacement position and the rotation angle, and the rotary displacement position and the rotation angle can be detected according to the arctangent value.

[0061] In one embodiment, in the step S300, if the magnetization direction is along the thickness direction or the circular arc radial direction of the magnet, the calculation of the magnetization data is determined by the following cases:

[0062] According to the magnetic induction strength distribution of the sensor, the magnetic induction strength distribution of the magnetization along the thickness direction or the circular arc radial direction of the magnet is shown in Figure 8 and Figure 9 respectively, in which the vertical coordinate is the magnetic induction strength, and the horizontal coordinate is the displacement stroke; the arctangent operation is performed on any two components of the X-axis magnetic induction strength, the Y-axis magnetic induction strength, and the Z-axis magnetic induction strength.

[0063] The working principle and beneficial effects of the above technical solution are: the present solution provides a magnetization data determination method along the thickness direction or the circular arc radial direction as the magnetization direction, which adapts to the characteristics of the magnetization direction, so as to better implement the magnetization process, guarantee the magnetization quality, and improve the magnet yield; when magnetized along the thickness direction and the radial direction, the present solution can be used for the design of three-axis angle sensors; the value of the arctangent operation has a one-to-one correspondence with the rotary displacement position and the rotation angle, and the rotary displacement position and the rotation angle can be detected according to the arctangent value.

[0064] In one embodiment, in the step S300, the magnetization process is performed by using a pulse magnetic field that is adapted to the magnetization direction and the magnetization data of the magnet, and the pulse magnetic field is realized by a pulse current through the magnetization device.

[0065] The working principle and beneficial effects of the above technical solution are: the present solution realizes the magnetization of the magnet block by providing a pulse magnetic field for the magnet block through the magnetization device, and the pulse magnetic field is realized by the electromagnetic conversion of the provided pulse current through the magnetization device; the strength of the pulse magnetic field can be determined according to the magnetization data of the magnet, and the adjustment of the strength of the pulse magnetic field can be realized by controlling the pulse current; the present solution can realize the magnetization under precise control, thereby guaranteeing the quality and consistency of the magnet.

[0066] In one embodiment, as shown in Figure 6As shown, the magnetizing device is configured with a power input control circuit for controlling the magnetizing pulse current during magnetizing treatment;

[0067] The power input control circuit comprises a current limiting adjustment module, a field effect tube Q1, a reference voltage module, an amplifier U1, an error amplifier U2, variable resistors R1, R2 and R3;

[0068] The input end of the current limiting adjustment module is connected with the power supply, and the output end of the current limiting adjustment module is connected with the source of the field effect tube Q1;

[0069] The control end of the current limiting adjustment module is connected with pin 4 of the error amplifier U2, the input pin 1 of the error amplifier U2 is connected with the output pin 4 of the amplifier U1 through the variable resistor R1, pin 3 of the error amplifier U2 is connected with the reference voltage module and pin 3 of the amplifier U1 respectively, and the output pin 5 of the error amplifier U2 is connected with the gate of the field effect tube Q1;

[0070] The input pin 1 of the amplifier U1 is connected with the reference voltage module, the input pin 2 of the amplifier U1 is connected with one end of the variable resistor R2 and one end of the variable resistor R3 respectively, the other end of the variable resistor R2 is connected with the input pin 1 of the error amplifier U2, and the other end of the variable resistor R3 is grounded;

[0071] The input pin 2 of the error amplifier U2 is connected with the drain of the field effect tube Q1 as an output end.

[0072] The working principle and beneficial effects of the above technical solution are as follows: by setting the power input control circuit, the reference voltage provided by the reference voltage module is used as a reference, the reference voltage is processed by the amplifier U1, multiple variable resistors and the error amplifier U2, and then acts on the current limiting adjustment module and the field effect tube Q1, so as to control the output voltage of the power supply and accurately control the output current, thereby ensuring the magnetization quality and consistency of the magnetization quality, improving the yield rate; the current limiting adjustment module is used to limit the current supplied to the source of the field effect tube Q1, so that the voltage output by the power supply is stable, the current control is accurate, the risk is controllable, and the service life of the magnetizing device is improved; the power input control circuit used in the present solution has fast response speed and excellent transient response characteristics, and can realize stable work under ultra-low voltage difference by matching capacitors.

[0073] In one embodiment, during the magnetizing treatment process, the pulse current of the magnetizing device is detected in real time, and a self-adaptive filter is used to filter the detection signal; the filtering process adopts the following algorithm:

[0074] y(n)=W T (n)X(n)

[0075] e(n) = d(n) - y(n)

[0076]

[0077] W(n+1) = W(n) + 2μ(n)e(n)X(n)

[0078] Wherein, y(n) represents the output of the detection signal at n time, alpha, beta is the adjustment parameter of mu(n), mu(n) represents the step factor of the adaptive filter, d(n) represents the expected detection signal at n time, e(n) represents the difference between the expected detection signal and the output detection signal, X(n) represents the input vector of the adaptive filter at n time, W(n) represents the tap weight vector of the adaptive filter at n time, W(n+1) represents the tap weight vector of the adaptive filter at n+1 time, W T (n) represents the tap weight vector of the adaptive filter after transposition at n time.

[0079] The working principle and beneficial effects of the above technical scheme are that the filtering algorithm of the adaptive filter is used to improve the convergence speed of the filtering algorithm, improve the filtering precision, further ensure the accuracy of the detection signal, and ensure the accuracy of the detection result of the pulse current; The adaptive filter also considers the steady-state error, and improves the performance of the filtering algorithm.

[0080] In one embodiment, the magnetization process uses a foolproof structure as an identification mark for automatically determining the magnetization direction used;

[0081] By real-time shooting of the magnet block image, the foolproof structure image in the magnet block image is recognized, the foolproof structure image of the shot magnet block image is compared with the pre-stored foolproof structure image, the form of the foolproof structure used by the magnet block to be magnetized is determined, the magnet blocks are classified according to the foolproof structure, the magnetization direction of the magnet blocks with different classified foolproof structures is different, and the magnetization direction of the magnet blocks with the same classified foolproof structure is the same;

[0082] Before similarity comparison, the similarity feature quantity of the foolproof structure image is calculated by the following method:

[0083] The foolproof structure image is divided into a target and a background, and a foolproof structure image feature classification set Team(z) is obtained:

[0084] Team(z) = argmax(y k z+e k ), k = 1, 2,..., R,

[0085] In the formula, e k represents the shape error, y kThe strength of the foolproof structure image detection is represented by z, the clustering center of the foolproof structure image classification, and the gray level i of the foolproof structure image is obtained by machine self-adaptive learning id (z) is:

[0086] i id (z) = bml(g kl z + f kl )

[0087] In the formula, l = 1, 2, …, R, l represents a texture feature value, k is a coefficient, and k ≠ l0, bml represents a binary mapping rule, g kl represents the gray value of the original foolproof structure image, f kl represents the gray value of the enhanced foolproof structure image; a foolproof structure image feature distribution set is established, adaptive classification is performed on the foolproof structure image feature distribution set, and the similarity feature quantity is obtained as:

[0088]

[0089] Wherein, x c represents a foolproof structure image feature distribution set of c-dimensional data, x d represents a foolproof structure image feature distribution set of d-dimensional data, y cm represents c-dimensional data composition, y dm represents d-dimensional data composition, m represents the number of data composition, and p represents the dimension of the foolproof structure image.

[0090] The working principle and beneficial effects of the above technical solution are as follows: according to the similarity feature quantity extraction result, the edge contour feature detection of the foolproof structure image of the magnet block with different texture distributions is performed, and then the optimization classification of the foolproof structure category of the magnet block is realized according to the edge feature marking result, the classification of the foolproof structure image is realized through the calculation of the similarity feature quantity, and the recognition accuracy of the foolproof structure category is improved.

[0091] The magnet for the sensor of the present application is applied to the sensor, as shown in Figure 10 and 11 , the magnet 1 and the Hall chip 4 are located on the same side of the circuit board 5, the Hall chip 4 is arranged on the outer periphery of the arc-shaped structure of the magnet 1, the Hall chip 4 is connected with the circuit board 5, and the magnet 1 can rotate around the rotating shaft 6; when not in use or not in action, the initial position (in the inaction state, i.e. 0 degrees) of the magnet and the relative position of the Hall chip are as shown in Figure 10 ; when the sensor is measured in use, the magnet in the sensor will make a rotating action around the rotating shaft 6, as shown in Figure 11 , the relative position of the magnet and the Hall chip after the magnet rotates 45 degrees in the arc-shaped arrow direction.

[0092] It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

Claims

1. A magnetization method for a magnet of a sensor, characterized by, The application relates to a magnet for a sensor. The magnet material and size are selected according to the maximum displacement stroke that can be detected by the sensor, and a magnet block with a circular-arc tile structure is manufactured; The magnetization direction of the magnet is determined according to the relationship between the magnetic induction intensity of the sensor and the rotary displacement position and the rotary angle based on the Hall effect; the magnetization direction is along one of the length, thickness or circular-arc radial direction of the magnet; The magnetization data of the magnet are calculated; the magnet block is magnetized according to the magnetization direction and the magnetization data, so as to obtain the magnet for the sensor; When the magnet block with the circular-arc tile structure is manufactured, an asymmetric fool-proof structure is arranged on the arc-shaped inner wall, the arc-shaped outer wall, the length direction end or the thickness direction upper and lower end surface of the magnet block; If the magnetization direction is along the thickness direction or the circular-arc radial direction of the magnet, the magnetization data are calculated through the following conditions: According to the magnetic induction intensity distribution of the sensor, any two components of the X-axis magnetic induction intensity, the Y-axis magnetic induction intensity and the Z-axis magnetic induction intensity are subjected to arctangent operation; The fool-proof structure is used as an identification mark for automatically determining the adopted magnetization direction during the magnetization process; The magnet block image is photographed in real time, the fool-proof structure image in the magnet block image is recognized, the fool-proof structure image of the photographed magnet block image is compared with the pre-stored fool-proof structure image, the adopted fool-proof structure form of the magnet block to be magnetized is determined, the magnet blocks are classified according to the fool-proof structures, the magnetization directions of the magnet blocks with different classified fool-proof structures are different, and the magnetization directions of the magnet blocks with the same classified fool-proof structure are the same.

2. The magnetization method of a magnet for a sensor according to claim 1, characterized by, If the magnetization direction is along the length direction of the magnet, the magnetization data are calculated through the following conditions: According to the magnetic induction intensity distribution of the sensor, the Z-axis magnetic induction intensity perpendicular to the rotary displacement stroke has a substantially linear relationship with the rotary position of the magnet; the magnet of the sensor based on the Hall effect detects the rotary displacement position and the rotary angle through the measurement of the Z-axis magnetic induction intensity according to the relationship between the Z-axis magnetic induction intensity and the rotary displacement position and the rotary angle; or any two components of the X-axis magnetic induction intensity, the Y-axis magnetic induction intensity and the Z-axis magnetic induction intensity are subjected to arctangent operation.

3. The magnetization method of a magnet for a sensor according to claim 1, characterized by, The magnetization process is performed by using a pulse magnetic field which is suitable for the magnetization direction and the magnetization data of the magnet, and the pulse magnetic field is realized by using a pulse current of a magnetization device.

4. The magnetization method of a magnet for a sensor according to claim 3, characterized by, The magnetization device is provided with a power input control circuit which is used for controlling the pulse current for magnetization during the magnetization process; The power input control circuit comprises a current-limiting adjustment module, a field effect transistor Q1, a reference voltage module, an amplifier U1, an error amplifier U2, variable resistors R1, R2 and R3; The input end of the current-limiting adjustment module is connected with a power supply, and the output end of the current-limiting adjustment module is connected with the source electrode of the field effect transistor Q1; The control end of the current-limiting adjustment module is connected with pin 4 of the error amplifier U2, the input pin 1 of the error amplifier U2 is connected with the output pin 4 of the amplifier U1 through the variable resistor R1, pin 3 of the error amplifier U2 is connected with the reference voltage module and pin 3 of the amplifier U1 respectively, and the output pin 5 of the error amplifier U2 is connected with the gate electrode of the field effect transistor Q1. The input pin 1 of the amplifier U1 is connected with a reference voltage module, the input pin 2 of the amplifier U1 is connected with one end of a variable resistor R2 and one end of a variable resistor R3 respectively, the other end of the variable resistor R2 is connected with the input pin 1 of an error amplifier U2, and the other end of the variable resistor R3 is grounded; The input pin 2 of the error amplifier U2 is connected with the drain of the field effect tube Q1 as an output end.

5. The magnetization method of a magnet for a sensor according to claim 3, characterized by, During the magnetization process, the pulse current of the magnetization equipment is detected in real time, and an adaptive filter is used to filter the detection signal.

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