Magnetic encoder

Abstract

The present invention discloses a magnetic encoder, which comprises a rotor disk. The magnetic encoder is provided with a plurality of target zero positions with zero magnetic density along the circumference of the rotor disk. The rotor disk is provided with a plurality of magnetic pole portions distributed along the circumference, and the sizes of at least some of the magnetic pole portions are different. In two adjacent magnetic pole portions, a magnetic pole neutral plane between the two magnetic pole portions and / or an end surface opposite to the two magnetic pole portions deviate from the corresponding target zero position setting, so that the actual zero position of the magnetic field formed by the plurality of magnetic pole portions is located at the target zero position correspondingly. By reasonably adjusting the size of each magnetic pole portion, the actual zero position of the magnetic density of the actual magnetic field of the rotor disk is made to coincide with the target zero position of the magnetic density of the theoretical magnetic field is made to coincide, so that the magnetic sensor on the stator disk can detect the actual zero position of the magnetic field more accurately, thereby realizing accurate encoding of the position angle and improving the measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of encoders, and in particular to a magnetic encoder. Background Art

[0002] An encoder is a device that compiles and converts signals or data into a signal form that can be used for communication, transmission and storage. Among them, the rotary encoder can directly convert the measured angular displacement into a digital signal, and is widely used in automatic measurement and control systems. However, with the continuous improvement of the degree of industrial automation, higher and higher requirements are put forward for the monitoring of parameters including rotation speed and rotation direction. Although some products have this function, their structure is generally more complicated, difficult to assemble, high in production cost and low in resolution. Summary of the invention

[0003] In view of the defects of traditional encoders, the inventors proposed a magnetic encoder, which needs to be magnetized in the axial direction and will have the problem of magnetic field zero point offset, resulting in low measurement accuracy. Therefore, how to optimize the magnetic encoder to improve the measurement accuracy is an issue that needs to be solved urgently.

[0004] To achieve the above-mentioned purpose, the present invention proposes a magnetic encoder, which includes a rotor disk, and the magnetic encoder is provided with a plurality of target zero positions with zero magnetic density along the circumferential direction of the rotor disk, and the rotor disk is provided with a plurality of magnetic pole portions distributed along the circumferential direction, and at least some of the magnetic pole portions have different sizes, and in two adjacent magnetic pole portions, the magnetic pole neutral plane between the two magnetic pole portions and / or the end faces relative to the two magnetic pole portions deviate from the setting corresponding to the target zero position, so that the actual zero position of the magnetic field formed by the plurality of magnetic pole portions corresponds to the target zero position.

[0005] Optionally, in the circumferential direction of the rotor disk, a central angle corresponding to an offset between a magnetic pole neutral plane between two magnetic pole portions and / or opposite end surfaces of two magnetic pole portions and a corresponding target zero point position is α, and -3°≤α≤3°.

[0006] Optionally, in the circumferential direction of the rotor disk, the central angle between two adjacent target zero point positions is β, and β = (Ni*360° / K)±δ (i = 1, 2, 3...P, P is the number of the magnetic pole portions), where δ is the allowable error, K is a positive integer, Ni is a positive integer, and Ni<K.

[0007] Optionally, δ≤0.5°.

[0008] Optionally, the plurality of magnetic pole portions include a plurality of first magnetic pole portions and a plurality of second magnetic pole portions that are staggered, and each of the first magnetic pole portions and each of the second magnetic pole portions are axially magnetized and have opposite polarities.

[0009] Optionally, the rotor disk has a magnetic ring, on which a plurality of magnetic regions distributed along the circumference of the rotor disk are formed to form a plurality of the first magnetic pole portions and a plurality of the second magnetic pole portions.

[0010] Optionally, adjacent first magnetic pole portions and second magnetic pole portions are at least partially connected.

[0011] Optionally, a groove is provided at the junction of the first magnetic pole portion and the second magnetic pole portion, and the groove extends in the radial direction of the rotor disk.

[0012] Optionally, a non-magnetic region is provided between adjacent first magnetic pole portions and second magnetic pole portions.

[0013] Optionally, the rotor disk has a plurality of magnetic blocks spaced apart along the circumferential direction, and each of the magnetic blocks forms a plurality of the first magnetic pole portions and a plurality of the second magnetic pole portions.

[0014] Optionally, a spacing area is provided between adjacent first magnetic pole portions and second magnetic pole portions, and the spacing area can be selected to have different sizes.

[0015] Optionally, the plurality of magnetic pole portions are all axially magnetized and have the same polarity, the plurality of magnetic pole portions are arranged at intervals, and the intervals between at least some of the magnetic pole portions are different.

[0016] Optionally, the magnetic encoder also includes a stator disk, which is coaxially arranged with the rotor disk and is located on the side of the rotor disk where the magnetic pole portion is axially provided. The rotor disk can rotate relative to the stator disk. The stator disk is provided with a plurality of magnetic sensors distributed along the circumferential direction. The plurality of magnetic sensors are used to generate sensing signals by sensing changes in the magnetic field.

[0017] Optionally, the magnetic sensor is a Hall sensor, and a plurality of the Hall sensors are evenly distributed along the circumferential direction.

[0018] Optionally, dimensions of the plurality of magnetic pole portions include a length dimension along a circumferential direction of the rotor disk.

[0019] The magnetic encoder is provided with a plurality of target zero positions of zero magnetic density along the circumference of the rotor disk, and at least some of the magnetic pole portions have different sizes. In two adjacent magnetic pole portions, the magnetic pole neutral plane between the two magnetic pole portions and / or the end surfaces relative to the two magnetic pole portions deviate from the corresponding target zero position setting. By reasonably adjusting the size of each magnetic pole portion, the magnetic pole neutral plane between the two magnetic pole portions and / or the end surfaces relative to the two magnetic pole portions deviate from the corresponding target zero position setting, thereby making the actual zero position of the magnetic density of the actual magnetic field of the rotor disk zero coincide with the target zero position of the magnetic density of the theoretical magnetic field zero, so that the magnetic sensor on the stator disk can detect the actual zero position of the magnetic field more accurately, realize accurate encoding of the position angle, and improve the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of the main structure of an embodiment of a magnetic encoder provided by the present invention;

[0022] Figure 2 for Figure 1 A schematic diagram of the structure of the middle rotor disc viewed from above;

[0023] Figure 3 for Figure 1 A schematic diagram of the top view of the middle stator disc;

[0024] Figure 4 for Figure 1 Schematic diagram of the distribution of the magnetic flux density of the middle rotor disk along the circumferential direction and the corresponding magnetic poles;

[0025] Figure 5 for Figure 1 A schematic diagram of the interface formed by the middle magnetic ring between two adjacent magnetic poles;

[0026] Figure 6 for Figure 1 Schematic diagram of the middle magnetic ring forming a non-magnetic area between two adjacent magnetic poles;

[0027] Figure 7 for Figure 1 Schematic diagram of a groove formed between two adjacent magnetic poles of the middle magnetic ring;

[0028] Figure 8 for Figure 1A first distribution diagram of a plurality of magnetic blocks;

[0029] Fig. 9 for Figure 1 A second distribution diagram of the plurality of magnetic blocks;

[0030] Fig.10 This is a schematic diagram of another embodiment of the magnetic encoder provided by the present invention.

[0031] Description of Figure Numbers:

[0032] Label name Label name 100 Magnetic encoder 15a Spacer 1 Rotor disc 2 Stator plate 11 Magnetic pole 21 Magnetic Sensor 11a The first magnetic pole 211 Hall sensor 11b The second magnetic pole 3 Magnetic ring 12a Target zero position 31 Magnetic Zone 13a Magnetic neutral plane 32 Non-magnetic area 14a Grooves 4 Magnetic Blocks

[0033] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0036] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0037] An encoder is a device that compiles and converts signals or data into a signal form that can be used for communication, transmission and storage. Among them, the rotary encoder can directly convert the measured angular displacement into a digital signal, and is widely used in automatic measurement and control systems. However, with the continuous improvement of the degree of industrial automation, higher and higher requirements are put forward for the monitoring of parameters including rotation speed and rotation direction. Although some products have this function, their structure is generally more complicated, difficult to assemble, high in production cost and low in resolution.

[0038] In view of the defects of traditional encoders, the inventors proposed a magnetic encoder, which needs to be magnetized in the axial direction, and there will be a problem of magnetic field zero point offset, resulting in low measurement accuracy. In view of this, the present invention proposes a magnetic encoder, which optimizes the structure of the existing magnetic encoder and improves the measurement accuracy, wherein: Figures 1 to 10 A schematic structural diagram of an embodiment of the magnetic encoder provided by the present invention.

[0039] See also Figures 1 to 4 The magnetic encoder 100 includes a rotor disk 1 and a stator disk 2 .

[0040] The stator disk 2 is coaxially arranged with the rotor disk 1 and is located on the side of the rotor disk 1 where the magnetic pole portion 11 is axially arranged. The rotor disk 1 can rotate relative to the stator disk 2. The stator disk 2 is provided with a plurality of magnetic sensors 21 distributed along the circumferential direction. The plurality of magnetic sensors 21 are used to generate sensing signals by sensing changes in the magnetic field.

[0041] That is, when the rotor disk 1 rotates, the magnetic field of the rotor disk 1 will change, thereby causing the magnetic field where the magnetic sensor 21 is located to change, and the rotation angle can be obtained through the measurement of the magnetic sensor 21.

[0042] The magnetic sensor 21 has high sensitivity and good stability, and is easy to be miniaturized and integrated, thereby improving the measurement accuracy.

[0043] Furthermore, a plurality of magnetic pole portions 11 of different sizes are arranged on the rotor disk 1, and the coverage areas of the magnetic pole portions 11 relative to the stator disk 2 on the circumference are different. When the rotor disk 1 rotates relative to the stator disk 2, the magnetic sensor 21 measures the magnitude and direction of the magnetic field generated by the rotor disk 1 and converts it into an electrical signal, and calculates the relative rotation angle between the stator disk 2 and the rotor disk 1. Such a configuration has a compact structure and high efficiency, and can realize the encoding of the position angle.

[0044] In one embodiment, the magnetic sensor 21 is a Hall sensor 211, and a plurality of the Hall sensors 211 are evenly distributed along the circumference. The Hall sensor 211 is a magnetic field sensor made according to the Hall effect, and is widely used in industrial automation technology, detection technology, information processing, etc. In the embodiment corresponding to the use of 6 Hall sensors 211, the steps of the position resolution method of the magnetic encoder 100 are as follows:

[0045] The reading of each Hall sensor 211 is compared with a preset threshold value. If the reading is greater than the threshold value, it is considered that the state of the Hall sensor 211 is 1; if the reading is less than the threshold value, it is considered that the state of the Hall sensor 211 is 0.

[0046] According to the states of the six Hall sensors 211, the sensor states are combined to calculate the gray code area corresponding to the current turning angle, and each gray code area corresponds to a turning angle range.

[0047] According to the gray code area calculated in the above steps and the accurate readings of the six Hall sensors 211 , the accurate relative rotation angle between the stator disk 2 and the rotor disk 1 can be calculated.

[0048] When a plurality of magnetic pole portions 11 of different sizes are provided on the rotor disk 1, the problem of magnetic field zero point offset will occur, resulting in low measurement accuracy. At this time, it is necessary to actually adjust the size of each magnetic pole portion 11 accordingly so that in the circumferential direction of the rotor disk 1, the actual zero point position where the magnetic flux density of the actual magnetic field is zero coincides with the target zero point position 12a where the magnetic flux density of the theoretical magnetic field is zero, that is, there is a problem of magnetic field zero point offset verification.

[0049] Specifically, in one embodiment, the magnetic encoder 100 includes a rotor disk 1, and the magnetic encoder 100 is provided with a plurality of target zero positions 12a with zero magnetic density along the circumferential direction of the rotor disk 1, and the rotor disk 1 is provided with a plurality of magnetic pole portions 11 distributed along the circumferential direction, and at least some of the magnetic pole portions 11 have different sizes. In two adjacent magnetic pole portions 11, a magnetic pole neutral plane 13a between the two magnetic pole portions 11 and / or the opposite end surfaces of the two magnetic pole portions 11 deviate from the setting corresponding to the target zero position 12a.

[0050] In the technical solution of the present invention, the magnetic encoder 100 is provided with a plurality of target zero positions 12a with zero magnetic density along the circumference of the rotor disk 1, and the sizes of at least some of the magnetic pole portions 11 are different. In two adjacent magnetic pole portions 11, the magnetic pole neutral plane 13a between the two magnetic pole portions 11 and / or the end surfaces of the two magnetic pole portions 11 are offset from the corresponding target zero position 12a. By reasonably adjusting the size of each magnetic pole portion 11, the magnetic pole neutral plane 13a between the two magnetic pole portions 11 and / or the end surfaces of the two magnetic pole portions 11 are offset from the corresponding target zero position 12a. Thus, the actual zero position of the magnetic density of the actual magnetic field of the rotor disk 1 with zero magnetic density coincides with the target zero position 12a of the theoretical magnetic field with zero magnetic density. This enables the magnetic sensor 21 on the stator disk 2 to detect the actual zero position of the magnetic field more accurately, thereby achieving accurate encoding of the position angle and improving the measurement accuracy.

[0051] It should be noted that the magnetic pole neutral plane 13a is a position plane between the two magnetic pole portions 11 along the circumference of the rotor disk 1, that is, the physical middle plane of the structure, and the magnetic pole neutral plane 13a is a radial plane of the rotor disk 1. For example, there is an interface between the two magnetic pole portions 11, that is, the interface is the magnetic pole neutral plane 13a; there is a non-magnetic area 32 between the two magnetic pole portions 11, then the radial plane where the middle position of the non-magnetic area 32 is located is the magnetic pole neutral plane 13a; there is a dividing area between the two magnetic pole portions 11, such as a splicing seam, or a disconnected cut, etc., then the radial plane where the middle position of the splicing seam is located or the radial plane where the middle position of the disconnected cut is located is the magnetic pole neutral plane 13a.

[0052] The multiple magnetic pole portions 11 are distributed in the circumferential direction of the rotor disk 1, and the magnitude and direction of the magnetic field may change. Therefore, the magnetic field density may be unevenly distributed in the circumferential direction of the rotor disk 1. Of course, there may also be an actual zero point position where the magnetic field density is zero. There may be multiple actual zero point positions distributed in the circumferential direction of the rotor disk 1.

[0053] In addition, it should be noted that, in an embodiment where the polarities of the adjacent magnetic pole portions 11 are opposite and there is an interface between the two, it is necessary to reasonably adjust the size of the magnetic pole portion 11 so that the magnetic pole neutral plane 13a between the two magnetic pole portions 11 and the relative end faces of the two magnetic pole portions 11 are both deviated from the corresponding target zero point position 12a; in an embodiment where the polarities of the adjacent magnetic pole portions 11 are opposite and there is a gap between the two, it is necessary to reasonably adjust the size of the magnetic pole portion 11 so that the magnetic pole neutral plane 13a between the two magnetic pole portions 11 is deviated from the corresponding target zero point position 12a; in an embodiment where the polarities of the adjacent magnetic pole portions 11 are the same and there is a gap between the two, it is necessary to reasonably adjust the size of the magnetic pole portion 11 so that the relative end faces of the two magnetic pole portions 11 are deviated from the corresponding target zero point position 12a.

[0054] The adjustment size of the offset is associated with the size of the two adjacent magnetic pole portions 11. In one embodiment, in the circumferential direction of the rotor disk 1, the central angle corresponding to the offset between the magnetic pole neutral plane 13a between the two magnetic pole portions 11 and / or the opposite end surfaces of the two magnetic pole portions 11 and the corresponding target zero point position 12a is α, and -3°≤α≤3°.

[0055] That is, the offset between the magnetic pole neutral plane 13a between the two magnetic pole portions 11 and / or the opposite end faces of the two magnetic pole portions 11 and the corresponding target zero point position 12a is less than 3°. Within this range, the relative size of the magnetic pole portions 11 is reasonably adjusted so that the actual zero point position of the actual magnetic field of the rotor disk 1 where the magnetic density is zero coincides with the target zero point position 12a where the magnetic density of the theoretical magnetic field is zero, so that the magnetic sensor 21 on the stator disk 2 can detect the target zero point position 12a of the magnetic field more accurately, thereby achieving precise encoding of the position angle and improving the measurement accuracy.

[0056] When designing the rotor disk 1, the magnetic flux density curve of the theoretical magnetic field along the circumference of the rotor disk 1 needs to be determined. Only according to the theoretical magnetic flux density distribution curve can the specific size of the magnetic pole portion 11 be quickly adjusted. Specifically, in one embodiment, refer to Figure 4 , in the circumferential direction of the rotor disk 1, the central angle between two adjacent target zero point positions 12a is β, and β = (Ni*360° / K)±δ (i = 1, 2, 3...P, P is the number of the magnetic pole portions), wherein δ is the allowable error, K is a positive integer, Ni is a positive integer, and Ni<K.

[0057] That is, there is a certain correlation between two adjacent target zero point positions 12a, which is convenient for uniformly adjusting the size of each magnetic pole portion 11, and the adjustment amount will also show a certain regularity, which is convenient for rapid adaptive adjustment.

[0058] The values ​​of N and K can be reasonably adjusted as needed. For example, in one embodiment, K is 36 and Ni is 3, then the center angle between two adjacent target zero point positions 12a is β=30°; K is 72 and Ni is 5, then the center angle between two adjacent target zero point positions 12a is β=25°, and so on.

[0059] In addition, δ is the manufacturing tolerance. In one embodiment, δ≤0.5°. Considering the manufacturing tolerance, it is easier to adjust the size of the magnetic pole portion 11.

[0060] In the embodiment of the present invention, the size specification of the magnetic pole portion 11 is not limited, for example, it can be a width dimension along the radial direction of the rotor disk 1, or a length dimension along the circumferential direction of the rotor disk 1. In order to facilitate the adjustment of the magnetic pole portion 11, the width dimension of the magnetic pole portion 11 along the radial direction of the rotor disk 1 is set to be consistent, and only the length dimension of the magnetic pole portion 11 along the circumferential direction of the rotor disk 1 needs to be adjusted, which is convenient for quick adjustment.

[0061] In the embodiment of the present invention, the specific distribution form of the magnetic pole portion 11 is not limited. In one embodiment, please refer to Figures 5 to 7 The plurality of magnetic pole portions 11 include a plurality of first magnetic pole portions 11a and a plurality of second magnetic pole portions 11b that are staggered, and each of the first magnetic pole portions 11a and each of the second magnetic pole portions 11b are axially magnetized and have opposite polarities.

[0062] That is, one of the first magnetic pole portion 11a and the second magnetic pole portion 11b is an N pole, and the other is an S pole, and the rotor disk 1 is distributed with staggered N poles and S poles on the circumference. Since among the plurality of first magnetic pole portions 11a and the plurality of second magnetic pole portions 11b, some of the first magnetic pole portions 11a have different sizes, or some of the second magnetic pole portions 11b have different sizes, or some of the first magnetic pole portions 11a and some of the second magnetic pole portions 11b have different sizes, or all of the above situations exist, the N pole and the S pole are unevenly distributed on the circumference of the rotor disk 1. Specifically, the magnetic sensor 21 outputs an alternating signal, which can accurately sense the state.

[0063] In the above-mentioned embodiment, magnetization can be performed in the form of a magnetic ring 3 or in the form of a magnetic block 4. Specifically, in the embodiment of magnetization using the magnetic ring 3, the rotor disk 1 has a magnetic ring 3, and a plurality of magnetic regions 31 distributed along the circumference of the rotor disk 1 are formed on the magnetic ring 3 to form a plurality of first magnetic pole portions 11a and a plurality of second magnetic pole portions 11b. With such an arrangement, only a single magnetic ring 3 needs to be manufactured and magnetized.

[0064] See also Figure 5 , the precise magnetization process can achieve a clear magnetic pole interface between two adjacent magnetic poles 11, however, in most cases, when the magnetic ring 3 is magnetized, magnetic field mixing will occur at the interface, that is, the magnetic pole interface between the adjacent first magnetic pole 11a and the second magnetic pole 11b is not clear enough. For this reason, grooves can be set on the physical shape of the magnetic ring to reduce the occurrence of mixed magnetism and make the magnetic interface relatively clear.

[0065] For further information, see Figure 7 A groove 14a is provided at the junction of the first magnetic pole portion 11a and the second magnetic pole portion 11b, and the groove 14a extends along the radial direction of the rotor disk 1, that is, after the magnetization is completed, the groove 14a is formed on the magnetic ring 3 by cutting, or the groove 14a is formed before the magnetization. Through the setting of the groove 14a, the mixed magnetic area between the two magnetic pole portions 11 with different polarities is reduced, so that the magnetic flux density distribution in the circumferential direction of the rotor disk 1 is better.

[0066] It should be noted that the size of the groove 14a is not limited, for example, the depth of the groove 14a can be 1 / 3, 1 / 4, 1 / 5, etc. of the thickness of the magnetic pole portion 11, and the shape is also not limited, such as square and semicircular arc, etc.

[0067] See also Figure 6 In another embodiment, a non-magnetic area 32 is provided between the adjacent first magnetic pole portions 11a and the second magnetic pole portions 11b, that is, the non-magnetic area 32 is used to reduce the mixed magnetic area between the two magnetic pole portions 11 with different polarities, so that the magnetic flux density distribution in the circumferential direction of the rotor disk 1 is better.

[0068] In another embodiment, see Figures 8 to 9 The rotor disk 1 has a plurality of magnetic blocks 4 spaced apart along the circumferential direction, and each of the magnetic blocks 4 forms a plurality of first magnetic pole portions 11 a and a plurality of second magnetic pole portions 11 b .

[0069] That is, the plurality of magnetic blocks 4 are processed and formed separately, and then installed on the rotor disk 1 to form a plurality of the first magnetic pole portions 11a and a plurality of the second magnetic pole portions 11b respectively, so that the magnetization process is simplified, and the magnetic field boundary at the junction between adjacent first magnetic pole portions 11a and second magnetic pole portions 11b is obvious, thereby reducing the magnetic field distortion, so that the magnetic flux density distribution in the circumferential direction of the rotor disk 1 is better.

[0070] In one embodiment, a spacing area 15a is provided between the adjacent first magnetic pole portion 11a and the second magnetic pole portion 11b, and the spacing between the two magnetic blocks 4 is not limited, for example, see Figure 8 , the distance between the two magnetic blocks 4 is relatively large, which is a large cutout; in addition, please refer to Fig. 9 The relative distance between the two magnetic blocks 4 is small, which is a joint seam, that is, the two magnetic blocks 4 are laterally abutted together. In the above two embodiments, the distance between the two magnetic blocks 4 can be adjusted according to actual needs.

[0071] In other embodiments, please refer to Fig.10 , the plurality of magnetic pole portions 11 are all axially magnetized and have the same polarity, that is, the magnetization direction is the same, the plurality of magnetic pole portions 11 are arranged at intervals, and the intervals between at least some of the magnetic pole portions 11 are different. That is, the magnetic pole distribution on the entire circumference is a single magnetic pole, and the polarity of each magnetic pole portion 11 is an N pole or an S pole. With respect to the method of setting two magnetic poles, it can be understood that the corresponding S pole or N pole is left blank, and the length of the blank position is the length of the corresponding magnetic pole portion 11. Such a setting does not affect the overall principle of the magnetic sensor 21 for position decoding, and saves materials. It should be noted that in this structural state, the single magnetic pole setting method does not have an absolute magnetic pole neutral plane after the magnetic field is formed, so the signal processing will be different, which will not be described in detail here. In addition, for the consideration of this embodiment, the positional relationship between the end face of the magnetic pole portion 11 and the corresponding target zero point position 12a is considered.

[0072] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A magnetic encoder, characterized in that: The magnetic encoder includes a rotor disk, and the magnetic encoder is provided with a plurality of target zero positions with zero magnetic density along the circumferential direction of the rotor disk. The rotor disk is provided with a plurality of magnetic pole portions distributed along the circumferential direction, and at least some of the magnetic pole portions have different sizes. In two adjacent magnetic pole portions, a magnetic pole neutral plane between the two magnetic pole portions and / or an opposite end surface of the two magnetic pole portions deviates from the setting corresponding to the target zero position, so that the actual zero position of the magnetic field formed by the plurality of magnetic pole portions corresponds to the target zero position.

2. The magnetic encoder according to claim 1, characterized in that In the circumferential direction of the rotor disk, a central angle corresponding to an offset between a magnetic pole neutral plane between two magnetic pole portions and / or opposite end surfaces of two magnetic pole portions and a corresponding target zero point position is α, and -3°≤α≤3°.

3. The magnetic encoder according to claim 1, characterized in that In the circumferential direction of the rotor disk, the central angle between two adjacent target zero point positions is β, and β=(Ni*360° / K)±δ, i=1, 2, 3...P, P is the number of the magnetic pole portions, wherein δ is the allowable error, K is a positive integer, Ni is a positive integer, and Ni<K.

4. The magnetic encoder according to claim 3, characterized in that δ≤0.5°.

5. The magnetic encoder according to claim 1, characterized in that The plurality of magnetic pole portions include a plurality of first magnetic pole portions and a plurality of second magnetic pole portions which are arranged alternately, and each of the first magnetic pole portions and each of the second magnetic pole portions are axially magnetized and have opposite polarities.

6. The magnetic encoder according to claim 5, characterized in that The rotor disk has a magnetic ring, on which a plurality of magnetic regions distributed along the circumference of the rotor disk are formed to form a plurality of the first magnetic pole portions and a plurality of the second magnetic pole portions.

7. The magnetic encoder according to claim 6, characterized in that Adjacent first magnetic pole portions and second magnetic pole portions are at least partially connected.

8. The magnetic encoder according to claim 7, characterized in that A groove is provided at a junction of the first magnetic pole portion and the second magnetic pole portion, and the groove extends in a radial direction of the rotor disk.

9. The magnetic encoder according to claim 6, characterized in that A non-magnetic region is provided between adjacent first magnetic pole portions and second magnetic pole portions.

10. The magnetic encoder according to claim 5, characterized in that The rotor disk has a plurality of magnetic blocks arranged at intervals in the circumferential direction, and each of the magnetic blocks forms a plurality of the first magnetic pole portions and a plurality of the second magnetic pole portions.

11. The magnetic encoder according to claim 10, characterized in that A spacing area is provided between adjacent first magnetic pole portions and second magnetic pole portions, and the spacing area can be selected to have different sizes.

12. The magnetic encoder according to claim 1, characterized in that The plurality of magnetic pole portions are all axially magnetized and have the same polarity. The plurality of magnetic pole portions are arranged at intervals, and the intervals between at least some of the magnetic pole portions are different.

13. The magnetic encoder according to claim 1, characterized in that: The magnetic encoder also includes a stator disk, which is coaxially arranged with the rotor disk and is located on the side of the rotor disk where the magnetic pole portion is axially arranged. The rotor disk can rotate relative to the stator disk. The stator disk is provided with a plurality of magnetic sensors distributed along the circumferential direction. The plurality of magnetic sensors are used to generate sensing signals by sensing changes in the magnetic field.

14. The magnetic encoder according to claim 13, characterized in that The magnetic sensor is a Hall sensor, and a plurality of the Hall sensors are evenly distributed along the circumferential direction.

15. The magnetic encoder according to claim 1, characterized in that: Dimensions of the plurality of magnetic pole portions include a length dimension along a circumferential direction of the rotor disk.

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