WO2023040085A1 - 磁鼓及具有其的磁编码器 - Google Patents

磁鼓及具有其的磁编码器 Download PDF

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WO2023040085A1
WO2023040085A1 PCT/CN2021/137089 CN2021137089W WO2023040085A1 WO 2023040085 A1 WO2023040085 A1 WO 2023040085A1 CN 2021137089 W CN2021137089 W CN 2021137089W WO 2023040085 A1 WO2023040085 A1 WO 2023040085A1
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magnetic
permanent magnet
ring
magnet ring
signal
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PCT/CN2021/137089
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English (en)
French (fr)
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成问好
王严
成沐阳
孟怀银
王昕�
成走程
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深圳市瑞达美磁业有限公司
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Publication of WO2023040085A1 publication Critical patent/WO2023040085A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means

Definitions

  • the invention belongs to the technical field of magnetic encoder design, and in particular relates to a magnetic drum and a magnetic encoder with the same.
  • a magnetic encoder is an angle or displacement measuring device composed of a magnetoresistive sensor, a magnetic drum, and a signal processing circuit as its main components. Magnetic encoders are widely used in industrial control, machinery manufacturing, ships, Textile, printing, aviation, aerospace, radar, communication, military and other fields.
  • the number of magnetic poles on the magnetic drum determines the resolution of the magnetic encoder.
  • the uniformity of the magnetic poles on the magnetic drum determines the quality of the output signal of the magnetic encoder.
  • the magnetic field strength and operating distance of the magnetic poles on the magnetic drum determine the structure of the magnetic encoder. and volume. In short, the magnetic drum has an important influence on the isotropic performance parameters of the magnetic encoder, and many performances of the magnetic drum are inseparable from the structure of the magnetic signal source on its circumference.
  • the drum of a magnetic encoder is mainly composed of a permanent magnet ring a as a magnetic signal source, a support ring b, and a rotating shaft c. If the permanent magnet ring on the outer circumference of the magnetic drum is expanded, its surface The arrangement of the magnetic poles is shown in Figure 2, and the cross-sectional magnetic pole structure of the permanent magnet on the outer circumference of the magnetic drum is shown in Figure 3.
  • the characteristics of the magnetic drum with this structure are: the source of the magnetic signal comes from the circumference of the magnetic drum N poles and S poles of permanent magnets distributed at intervals.
  • the disadvantages of the magnetic drum with this structure are: first, with the increase of the number of magnetic poles, the ratio of the magnetic field lines forming a closed loop between adjacent magnetic poles increases greatly, resulting in a rapid decrease in the working distance of the magnetic field, and the reluctance
  • the magnetic signal received by the sensor becomes weaker, which reduces the output signal quality of the magnetic encoder, and the number of magnetic poles on the magnetic drum has an important impact on the resolution of the magnetic encoder;
  • second, the difference between the N pole and the S pole on the magnetic drum There is a non-magnetic area in between, and the uniformity, width, and shape of the non-magnetic area directly determine the uniformity, width, and shape of the magnetic signal, and then determine the quality of the output signal of the magnetic encoder.
  • the uniformity of the magnetic signal source of the magnetic drum can only be controlled by magnetizing.
  • the manufacturing process of high-quality magnetic drum is very complicated, and the consistency is difficult to guarantee.
  • the uniformity of the magnetic signal source of the magnetic drum can only be controlled by magnetizing.
  • the manufacturing process of high-quality magnetic drum is very complicated, and the consistency is difficult to guarantee.
  • the following are the commonly used N/S poles formed by magnetizing the integral permanent magnet magnetic ring as the magnetic signal source, and several types of defects are prone to appear in the magnetic drum:
  • the first type the boundary of the non-magnetic area between the N/S magnetic poles is blurred, as shown in Figure 4;
  • the second type is the deformation of the non-magnetic zone boundary between N/S magnetic poles, as shown in Figure 5;
  • the third type is that the magnetic signal in this area suddenly decreases or even disappears because of the local defects in the magnet, as shown in Figure 6.
  • the present invention provides a magnetic drum and a magnetic encoder having the magnetic encoder to overcome the disadvantages in the related art that the magnetic drum has only one magnetic ring as a magnetic signal source, the output magnetic signal type is relatively single, and the signal accuracy is low.
  • the present invention provides a magnetic drum, which includes a support ring and a first permanent magnet ring and a second permanent magnet ring sleeved on the outer peripheral side of the support ring, the first permanent magnet ring and the second permanent magnet ring
  • Two permanent magnet rings are arranged in sequence along the axial direction of the support ring, and the first permanent magnet ring and the second permanent magnet ring are all unipolar magnetic rings with opposite polarities. Alternating first protrusions and first depressions along the circumferential direction are formed on the circumferential wall, and second protrusions and second depressions are formed on the outer circumferential wall of the second permanent magnet ring alternately along the circumferential direction.
  • the magnetic signal probe of the magnetic encoder is set opposite to the circumferential fit gap formed between the first permanent magnet ring and the second permanent magnet ring, so as to be able to obtain The N/S alternating magnetic signals formed by the magnetic ring and the second permanent magnetic ring; or, the magnetic signal probes of the magnetic encoder are respectively opposite to the outer circumferential walls of the first permanent magnetic ring and the second permanent magnetic ring It is set so that the N-pole magnetic signal and the S-pole magnetic signal formed by the first permanent magnet ring and the second permanent magnet ring can be obtained respectively, and the data is carried out based on the obtained N-pole magnetic signal and the S-pole magnetic signal The N/S alternating magnetic signal is obtained by processing.
  • the first protrusions alternate with the second recesses, and the first recesses alternate with the second protrusions.
  • the first protrusion, the first depression, the second protrusion, and the second depression are all formed by machining.
  • a magnetic isolation ring is further fitted on the support ring, and the first permanent magnetic ring and the second permanent magnetic ring form a clamp for the magnetic isolation ring.
  • the magnetic signal probe of the magnetic encoder is arranged opposite to the magnetic isolation ring, so as to be able to obtain the N/S alternating magnetic signal formed by the first permanent magnetic ring and the second permanent magnetic ring .
  • the axial height of the magnetic isolation ring is Da
  • the axial height of the first permanent magnetic ring is Db
  • the axial height of the second permanent magnetic ring is Dc
  • the first permanent magnetic ring is Dc.
  • the radial thicknesses of the permanent magnet ring and the second permanent magnet ring are equal to ⁇ R, and Da ⁇ 3(Db+Dc+ ⁇ R).
  • the magnetic drum further includes a third permanent magnet ring, and the outer ring wall of the third permanent magnet ring has alternating N poles and S poles along its axial direction.
  • the present invention also provides a magnetic encoder, including the above-mentioned magnetic drum.
  • the invention provides a magnetic drum and its magnetic encoder.
  • the support ring has at least a first permanent magnetic ring and a second permanent magnetic ring with opposite polarities on the outer ring wall, so that the magnetic drum of the magnetic drum
  • the signal source is improved from a single signal source in the prior art to at least two, so that the types of magnetic signals output by the magnetic drum are more abundant and the signal accuracy is higher.
  • Fig. 1 is a schematic diagram of the internal structure of a magnetic drum in the prior art
  • Fig. 2 is the outer circumferential surface development diagram of the radially magnetized magnetic ring (multi-pole magnetic ring) adopted by the magnetic drum in the prior art;
  • Fig. 3 is a sectional view (radial section) of the radially magnetized magnetic ring (multipole magnetic ring) in Fig. 2;
  • Fig. 4 is the schematic diagram of the boundary fuzzy defect of the non-magnetic zone of the permanent magnet ring in the prior art
  • Fig. 5 is the schematic diagram of the boundary deformation defect of the non-magnetic region of the permanent magnet ring in the prior art
  • FIG. 6 is a schematic diagram of deformation of magnetic signals caused by defects in permanent magnet rings without magnetic regions in the prior art
  • Fig. 7 is a schematic structural view of the first permanent magnet ring or the second permanent magnet in the magnetic drum of the embodiment of the invention.
  • Figure 8 is an expanded view of the outer circumferential surface when the outer ring wall of the permanent magnet ring in Figure 7 is a single N pole;
  • Fig. 9 is a sectional view (radial section) of the permanent magnet ring in Fig. 8;
  • Fig. 10 is another kind of structural representation of the first permanent magnet ring or the second permanent magnet in the magnetic drum of the embodiment of the invention.
  • Fig. 11 is a schematic diagram of the structure of the first permanent magnet ring and the second permanent magnet ring in the magnetic drum according to the embodiment of the present invention after they are circumferentially deployed.
  • the black rectangle shows the raised position
  • the white rectangle shows the concave position ;
  • Fig. 12 is the N/S alternately arranged magnetic signal that obtains at the outer peripheral surface of the magnetic drum shown in Fig. 11 (the first permanent magnet ring and the second permanent magnet ring form the circumference fit gap) place;
  • Fig. 13 is a schematic diagram of the structure of the first permanent magnet ring and the second permanent magnet ring in the drum according to another embodiment of the present invention after they are circumferentially deployed, wherein there is an axial distance between the first permanent magnet ring and the second permanent magnet ring ;
  • Figure 14 shows the two sets of magnetic signals corresponding to the first permanent magnet ring and the second permanent magnet ring respectively obtained at the outer circumferential surface of the magnetic drum shown in Figure 13, and the two are processed to obtain a set of N/S alternating aligned magnetic signals;
  • Fig. 15 is a schematic diagram of the structure of the first permanent magnet ring and the second permanent magnet ring in the drum according to another embodiment of the present invention after the circumferential development, wherein there is a magnetic isolation ring between the first permanent magnet ring and the second permanent magnet ring .
  • Figure 16 shows a set of N/S alternately arranged magnetic signals obtained by the magnetic probe detecting the position of the magnetic isolation ring
  • Fig. 17 is a structural diagram of the circumferentially deployed first permanent magnet ring and the second permanent magnet ring in the magnetic drum according to another embodiment of the present invention.
  • FIG. 18 shows that two first permanent magnet rings and one second permanent magnet ring are successively fitted on the outer peripheral surface of the support ring along its axial direction.
  • the first permanent magnet ring 11. The first protrusion; 12. The first depression; 2. The second permanent magnet ring; 21. The second protrusion; 22. The second depression; 3. The magnetic isolation ring; 4. The third permanent magnet ring.
  • a magnetic drum including a support ring and a first permanent magnet ring 1 and a second permanent magnet ring 2 fitted on the outer circumference of the support ring , the first permanent magnet ring 1 and the second permanent magnet ring 2 are sequentially arranged along the axial direction of the support ring, and the first permanent magnet ring 1 and the second permanent magnet ring 2 are both unipolar
  • the magnetic ring and the polarity are opposite.
  • the outer circumferential wall of the first permanent magnetic ring 1 is configured with first protrusions 11 and first depressions 12 alternately along its circumference.
  • the outer circumference of the second permanent magnetic ring 2 The wall is configured with alternate second protrusions 21 and second depressions 22 along its circumferential direction.
  • the support ring has at least a first permanent magnet ring 1 and a second permanent magnet ring 2 with opposite polarities on the outer ring wall at the same time, so that the magnetic signal source of the magnetic drum is controlled by a single magnetic signal source in the prior art.
  • the N/S alternating magnetic signals of the currently ubiquitous magnetic encoders are all obtained from a single magnetic ring, that is, a single magnetic ring is magnetized into N/S alternating magnetic poles.
  • the N/S magnetic poles of the magnetic encoder provided by the present invention The /S alternating magnetic signal can be obtained in two ways: the first way is to directly obtain the N/S alternating magnetic signal by detecting the circumferential joint between the first permanent magnet ring 1 and the second permanent magnet ring 2, and the second way
  • the N/S alternating magnetic signal is obtained by performing data processing on the unipolar magnetic signal obtained from the first permanent magnet ring 1 and the second permanent magnet ring 2 .
  • the magnetic signal probe of the magnetic encoder is set opposite to the circumferential fit gap formed between the first permanent magnet ring 1 and the second permanent magnet ring 2, so as to be able to obtain the The N/S alternating magnetic signals formed by the first permanent magnet ring 1 and the second permanent magnet ring 2 (as shown in Figure 11 and Figure 12); or, the magnetic signal probes that the magnetic encoder has are respectively connected with the first The outer circumferential walls of the permanent magnet ring 1 and the second permanent magnet ring 2 are relatively arranged so as to obtain the N pole magnetic signal and the S pole formed by the first permanent magnet ring 1 and the second permanent magnet ring 2 respectively.
  • the inner and outer diameter tolerance of the magnetic ring, the gap between the magnetic ring and the magnetizing coil during magnetization, etc. not only have many variable factors but also are difficult to control, and the N/S alternating magnetic signal of the magnetic encoder of the present invention
  • the uniformity and precision of the magnetic ring are achieved by controlling the machining accuracy of the protrusions and depressions of the magnetic ring during the machining process. It is obvious that the precision and consistency of machining are very easy to control.
  • the precision of the magnetic signal plays a decisive role in the precision of the magnetic encoder, so the present invention can significantly improve the precision of the magnetic encoder.
  • the first protrusions 11 alternate with the second recesses 22, the first recesses 12 alternate with the second protrusions 21, In this way, it can be prevented that the first protrusion 11 on the same axial direction corresponds to the second protrusion, and the first recess 12 corresponds to the second recess, so that the axially adjacent protrusions or recesses have zero magnetic field strength and cannot The magnetic signal required by the magnetic encoder.
  • the distance between the N pole and the S pole is obtained.
  • the magnetic signal has the best symmetry.
  • the staggered angle value it is related to the number of protrusions on the magnetic ring (similar to the number of teeth of the gear). The less the protrusions and depressions on the outer ring wall of the magnetic ring, the greater the staggered angle, and vice versa.
  • the maximum circumferential width of the first depression 12 is L, the radial height of the first protrusion 11 is H, and L>0.1H; and/or, the second depression 22
  • the maximum circumferential width is L, the radial height of the second protrusion 21 is H, L>0.1H, further, L>0.5H, to ensure that the magnetic drum is compatible with the protrusion 13 and the recess 14
  • the difference in magnetic field strength at the corresponding position can obtain the best detection resolution, which is beneficial to detection and utilization.
  • the width L of the first protrusion 11, the first depression 12, the second protrusion 21, and the second depression 22 can be equal or unequal, and the depth H of the depression can be equal or unequal, depending on the actual situation. Just design as required.
  • the first protrusion 11, the first depression 12 and the second protrusion 21, the second depression 22 are all formed by machining, for example, laser machining, so as to ensure that each The dimensional accuracy of each protrusion and groove can ensure the uniform distribution of the magnetic signal source in 360°, and can effectively overcome the blurring, deformation and width inconsistency of the non-magnetic area between the N pole and the S pole that is easily caused during the magnetization process of the magnetic ring. defects, greatly improving the quality of the magnetic signal source of the magnetic drum, and ensuring the accuracy of the magnetic encoder.
  • the support ring is also equipped with a magnetic isolation ring 3, and the first permanent magnet ring 1 and the second permanent magnet ring 2 are paired.
  • the magnetic isolation ring 3 forms a clamp, so that the magnitude of the magnetic signal deviation caused by the positional deviation of the magnetic signal probe can be greatly reduced.
  • the material of the magnetic isolation ring 3 must be a poor magnetic conductor, such as copper, aluminum, plastics, rubber, etc.
  • the axial height Da of the magnetic isolation ring 3 is not only related to the thickness of the magnetic ring in the radial direction (that is, the radial thickness ⁇ R), but also related to the axial height of the magnetic ring (that is, the first permanent magnetic ring 1Db and the axial height Dc of the second permanent magnet ring 2), but the axial height Da of the magnetic isolation ring 3 is larger and the magnetic signal detected at the magnetic isolation ring 3 is weaker, so the magnetic isolation
  • the axial height of the ring 3 cannot be too large, but as mentioned above, if the position of the magnetic probe can be guaranteed to be absolutely correct, it is possible even without the magnetic isolation ring 3, but in fact, in the actual implementation process, this Therefore, in some embodiments, the radial thicknesses of the first permanent magnet ring 1 and the second permanent magnet ring 2 are designed to be equal to ⁇ R, and Da ⁇ 3(Db+Dc+ ⁇ R), the best, Da ⁇ 2(Db+Dc+ ⁇ R), which can not
  • the magnetic field lines of each magnetic ring may form an independent loop, then either the magnetic signal of N/S alternating between the two magnetic rings cannot be detected or the detected The magnetic signal strength of N/S alternately appears is not enough, resulting in a decrease in the accuracy of the magnetic encoder.
  • the magnetic drum further includes a third permanent magnet ring 4 (as shown in FIG. 17 ), and the outer ring wall of the third permanent magnet ring 4 has alternating N poles and S poles along its axial direction.
  • the poles can further enrich the output magnetic signal types of the magnetic drum, which is beneficial to further improve the control accuracy after the comprehensive processing of the signal by the magnetic encoder chip.
  • more permanent magnet rings can be fitted on the outer peripheral surface of the support ring, so as to further enrich the output types of the magnetic drum magnetic signal.
  • the inner ring wall of the support ring is connected to the rotating shaft.
  • the inner ring wall of the support ring can be processed to form a necessary connection structure, such as a keyway (which can be a spline or a flat key), so that the magnetic drum can be disassembled more conveniently.
  • the shape of the first protrusion 11 and/or the second protrusion 21 is a rectangle, an isosceles trapezoid, an isosceles triangle, or an arc It should be noted that the specific shape of the first protrusion 11 and the second protrusion 21 is not particularly limited in the present invention, but no matter what specific shape it adopts, a plurality of the first protrusions 11, 21 Both the first protrusion 11 and the second protrusion 21 should have a centrally symmetrical structure with respect to the axis of the magnetic drum, so as to meet their requirements as a magnetic signal source for the encoder.
  • the permanent magnet ring body 1 is a radiation-oriented magnetic ring or an isotropic magnetic ring with monopolar magnetization characteristics.
  • the radiation alignment magnetic ring is made of at least one of NdFeB, SmCo, AlNiCo, and ferrite, that is, the radiation alignment magnetic ring can be made of a single material, It can also be made of multiple materials.
  • the isotropic magnetic ring characterized by unipolar magnetization is made of at least one of NdFeB and SmCo permanent magnets.
  • a magnetic encoder is also provided, including the above-mentioned magnetic drum. It can be understood that the magnetic encoder also includes the magnetoresistive sensor and the corresponding signal processing circuit board (that is, the magnetic encoder chip). This part is a conventional technology of the magnetic encoder and will not be repeated here.

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Abstract

一种磁鼓，包括支撑环（b）以及套装于支撑环（b）外圆周侧的第一永磁环（1）、第二永磁环（2），第一永磁环（1）与第二永磁环（2）沿支撑环（b）的轴向依次设置，第一永磁环（1）及第二永磁环（2）皆为单极磁环且极性相反，第一永磁环（1）的外圆周壁上构造有沿其周向交替的第一凸起（11）、第一凹陷（12），第二永磁环（2）的外圆周壁上构造有沿其周向交替的第二凸起（21）、第二凹陷（22）。既可以在第一永磁环（1）与第二永磁环（2）的圆周配合缝隙处直接获得N/S交替磁信号，也可以对从第一永磁环（1）与第二永磁环（2）上获得的单极磁信号进行数据处理后得到N/S交替磁信号，使磁鼓输出的磁信号类型更加丰富、信号精度更高。还提供一种磁编码器。

Description

磁鼓及具有其的磁编码器
本公开要求于2021年09月17日提交中国专利局、申请号为202111093908.8、发明名称为“磁鼓及具有其的磁编码器”的中国专利申请的优先权，其全部内容通过引用结合在本公开中。
技术领域
本发明属于磁编码器设计技术领域，具体涉及一种磁鼓及具有其的磁编码器。
背景技术
磁编码器是一种以磁阻传感器、磁鼓、信号处理电路为主要组成部分构成的角度或者位移测量装置。磁编码器因为有体积小、精密度高、分辨度高、无接触无磨损、高抗震、安装简单、使用寿命长、接口形式多等众多优点，因而广泛应用于工业控制、机械制造、船舶、纺织、印刷、航空、航天、雷达、通讯、军工等领域。
磁鼓上磁极的个数决定着磁编码器的分辨率，磁鼓上磁极的均匀性决定着磁编码器输出信号的质量，磁鼓上磁极的磁场强度和作用距离决定着磁编码器的结构和体积。总之，磁鼓对磁编码器的各向性能参数有着及其重要的影响，而磁鼓的很多性能又与其圆周上的磁信号源的结构密不可分。
如图1所示，磁编码器的磁鼓主要由作为磁信号源的永磁体环a、支撑环b和旋转轴c等部分组成，如果将磁鼓外圆周面的永磁体环展开，其表面磁极的排列方式如图2所示出，而磁鼓外圆周面永磁体展开图的剖面磁极结构如图3所示，具有这种结构的磁鼓的特点是：磁信号源来自于磁鼓圆周上间隔分布的永磁体的N极和S极。这种结构的磁鼓的不足之处是：第一，随着磁极个数的增加，磁力线在相邻磁极之间形成闭合回路的比例大幅度增加，致使磁场的作用距离迅速减小，磁阻传感器接收到的磁信号变弱，使磁编码器的输出信号质量降低，而磁鼓上磁极的个数对磁编码器的分辨率有着重要影响；第二，磁鼓上N极和S 极之间存在一个无磁区，无磁区均匀性、宽度、形状直接决定着磁信号的均匀性、宽度和形状，进而决定着磁编码器输出信号的质量。目前磁鼓的磁信号源的均匀性只能通过充磁的方法进行控制，高质量磁鼓制作工艺很复杂，一致性难以保证。目前磁鼓的磁信号源的均匀性只能通过充磁的方法进行控制，高质量磁鼓制作工艺很复杂，一致性难以保证。下面是目前普遍采用的通过对整体永磁体磁环充磁后形成的N/S极作为磁信号源磁鼓中容易出现几种缺陷形式：
第一种，N/S磁极间的无磁区边界模糊，如图4所示；
第二种，N/S磁极间的无磁区边界变形，如图5所示；
第三种，因为磁体中存在的局部缺陷导致位于该区域的磁信号突然减小甚至消失，如图6所示。
而相关技术中的磁编码器中的磁鼓大多只采用一个磁环形成磁信号源，磁信号源的输出磁信号类型较为单一，相应的控制精度(信号精度)较低。
发明内容
因此，本发明提供一种磁鼓及具有其的磁编码器，以克服相关技术中磁鼓仅具有一个磁环作为磁信号源，输出磁信号类型较为单一、信号精度较低的不足。
为了解决上述问题，本发明提供一种磁鼓，包括支撑环以及套装于所述支撑环外圆周侧的第一永磁环、第二永磁环，所述第一永磁环与所述第二永磁环沿所述支撑环的轴向依次设置，所述第一永磁环及所述第二永磁环皆为单极磁环且极性相反，所述第一永磁环的外圆周壁上构造有沿其周向交替的第一凸起、第一凹陷，所述第二永磁环的外圆周壁上构造有沿其周向交替的第二凸起、第二凹陷。
在一些实施方式中，磁编码器具有的磁信号探头与所述第一永磁环与所述第二永磁环之间形成的圆周配合缝隙相对设置，以能够获取到由所述第一永磁环及第二永磁环所形成的N/S交替磁信号；或者，磁编码器具有的磁信号探头分别与所述第一永磁环、所述第二永磁环的外圆周壁相对设置，以能够分别获取到所述第一永磁环、第二永磁环所形成的N极磁信号及S极磁信号，并基于获取的所述N极磁信号及S极磁信号进行数据处理得到N/S交替磁信号。
在一些实施方式中，沿着所述磁鼓的轴向，所述第一凸起与所述第二凹陷形成交替，所述第一凹陷与所述第二凸起形成交替。
在一些实施方式中，所述第一凸起、第一凹陷以及所述第二凸起、第二凹陷皆通过机加工的方式形成。
在一些实施方式中，所述支撑环上还套装有隔磁环，所述第一永磁环与所述第二永磁环对所述隔磁环形成夹持。
在一些实施方式中，磁编码器具有的磁信号探头与所述隔磁环相对设置，以能够获取到由所述第一永磁环及第二永磁环所形成的N/S交替磁信号。
在一些实施方式中，所述隔磁环的轴向高度为Da，所述第一永磁环的轴向高度为Db，所述第二永磁环的轴向高度为Dc，所述第一永磁环与所述第二永磁环的径向厚度相等且皆为△R，Da＜3(Db+Dc+△R)。
在一些实施方式中，Da＜2(Db+Dc+△R)。
在一些实施方式中，所述磁鼓还包括第三永磁环，所述第三永磁环的外环壁上具有沿其轴向交替的N极及S极。
本发明还提供一种磁编码器，包括上述的磁鼓。
本发明提供的一种磁鼓及具有其的磁编码器，所述支撑环上同时至少具有外环壁极性相反的第一永磁环及第二永磁环，使所述磁鼓的磁信号源由现有技术中的单个改进成为至少两个，如此使所述磁鼓输出的磁信号类型更加丰富、信号精度更高。
附图说明
图1为现有技术中磁鼓的内部结构示意图；
图2为现有技术中的磁鼓采用的径向充磁磁环(多极磁环)的外周面展开图；
图3为图2中的径向充磁磁环(多极磁环)的剖面图(径向剖面)；
图4为现有技术中永磁体环无磁区边界模糊缺陷的示意图；
图5为现有技术中永磁体环无磁区边界变形缺陷的示意图；
图6为现有技术中永磁体环无磁区缺陷导致磁信号变形的示意图；
图7中为发明实施例的磁鼓中第一永磁环或者第二永磁体的一种结构示意图；
图8为图7中的永磁环的外环壁为单一N极时的外圆周面展开图；
图9为图8中的永磁环的剖面图(径向剖面)；
图10为发明实施例的磁鼓中第一永磁环或者第二永磁体的另一种结构示 意图；
图11为本发明实施例的磁鼓中第一永磁环与第二永磁环周向展开后的结构示意图，图中黑色矩形示出了凸起位置，而白色矩形则示出了凹陷位置；
图12为图11所示的磁鼓外圆周面(第一永磁环与第二永磁环的形成的圆周配合缝隙处)处得到的N/S交替排列的磁信号；
图13为本发明另一实施例的磁鼓中第一永磁环与第二永磁环周向展开后的结构示意图，其中第一永磁环与第二永磁环之间具有轴向间隔；
图14示出了图13所示的磁鼓外圆周面处分别得到的第一永磁环与第二永磁环对应的两组磁信号并将两者进行数据处理得到一组N/S交替排列的磁信号；
图15为本发明又一实施例的磁鼓中第一永磁环与第二永磁环周向展开后的结构示意图，其中第一永磁环与第二永磁环之间具有隔磁环。
图16示出了磁探头检测隔磁环位置获得的一组N/S交替排列的磁信号；
图17为本发明又一实施例的磁鼓中第一永磁环与第二永磁环周向展开后的结构示意图；
图18示出了支撑环的外圆周面上沿其轴向依次套装有两个第一永磁环及一个第二永磁环。
附图标记表示为：
1、第一永磁环；11、第一凸起；12、第一凹陷；2、第二永磁环；21、第二凸起；22、第二凹陷；3、隔磁环；4、第三永磁环。
具体实施方式
结合参见图1至图18所示，根据本发明的实施例，提供一种磁鼓，包括支撑环以及套装于所述支撑环外圆周侧的第一永磁环1、第二永磁环2，所述第一永磁环1与所述第二永磁环2沿所述支撑环的轴向依次设置，所述第一永磁环1及所述第二永磁环2皆为单极磁环且极性相反，所述第一永磁环1的外圆周壁上构造有沿其周向交替的第一凸起11、第一凹陷12，所述第二永磁环2的外圆周壁上构造有沿其周向交替的第二凸起21、第二凹陷22。该技术方案中，所述支撑环上同时至少具有外环壁极性相反的第一永磁环1及第二永磁环2，使所述磁鼓的磁信号源由现有技术中的单个改进成为至少两个，如此使所 述磁鼓输出的磁信号类型更加丰富、信号精度更高。可以理解的是，当所述第一永磁环1的外环壁为N极时，其内环壁则为S极，当所述第二永磁环2的外环壁为S极时，内环壁为N极。
目前普遍存在的磁编码器的N/S交替磁信号都是从单一磁环上得到的，也就是将单个磁环充磁成N/S交替出现的磁极，本发明提供的磁编码器的N/S交替磁信号可以通过两种方式得到：第一种方式是通过检测第一永磁环1与第二永磁环2的周向结合部直接获得N/S交替磁信号，第二种方式是对从第一永磁环1与第二永磁环2上获得的单极磁信号进行数据处理得到N/S交替磁信号。与此相对应的是，磁编码器具有的磁信号探头与所述第一永磁环1与所述第二永磁环2之间形成的圆周配合缝隙相对设置，以能够获取到由所述第一永磁环1及第二永磁环2所形成的N/S交替磁信号(如图11与图12所示出)；或者，磁编码器具有的磁信号探头分别与所述第一永磁环1、所述第二永磁环2的外圆周壁相对设置，以能够分别获取到所述第一永磁环1、第二永磁环2所形成的N极磁信号及S极磁信号，并基于获取的所述N极磁信号及S极磁信号进行数据处理得到N/S交替磁信号(如图13与图14所示出)。需要特别指出的是，本发明与目前普遍使用磁编码器的另外一个最大不同之处是：目前普遍存在的磁编码器的N/S交替磁信号的均匀性和精度是通过控制充磁线圈的精度、磁环的内外径公差、充磁时磁环与充磁线圈间的间隙等众多因素来实现，不仅可变因素多而且难于控制，而本发明的磁编码器的N/S交替磁信号的均匀性和精度是机械加工过程中通过控制磁环的凸起与凹陷的加工精度来实现的，机械加工的精度和一致性非常容易控制是显而易见的。磁信号的精度对磁编码器的精度起着决定性的作用，所以本发明可以显著提高磁编码器的精度。
在一些实施方式中，沿着所述磁鼓的轴向，所述第一凸起11与所述第二凹陷22形成交替，所述第一凹陷12与所述第二凸起21形成交替，如此能够防止在同一轴向上的第一凸起11与第二凸起对应、第一凹陷12与第二凹陷对应设置导致的轴向相邻的凸起或者凹陷处的磁场强度为零不能提供磁编码器所需的磁信号。可以理解的，偏离所述第一永磁环1与第二永磁环2的正中间区域后就只能检测到一个磁极的磁信号，具体的，偏向外环壁是N极的磁环时检测到的是N极磁信号，偏向外环壁是S极的磁环时检测到的是S极磁信号，将检测不到N极和S极间隔分布的磁信号，要在两个磁环(也即所述第一永磁环1及第二永磁环2)的正中间位置得到N极和S极间隔的磁信号就必须让两个磁环的凸起或凹陷错开一个角度，错开的角度不同得到的N极和S极的信号 强度不同，当N极磁环的凸起刚好与S极磁环的凹陷相对应的时候(也即前述的技术方案)得到N极和S极间隔磁信号对称性最好。而至于错开的角度数值则与磁环上的凸起部分的数量(类似齿轮的齿数)有关，磁环外环壁的凸起与凹陷越少错开的角度越大，反之则越小，理论上，磁编码器磁磁鼓外圆周面上的磁极越多磁编码器的精度越高，所以相同直径的磁编码器磁鼓上磁极的数量多少是衡量磁编码器的精度的重要参数之一。
在一些实施方式中，所述第一凹陷12的最大周向宽度为L，所述第一凸起11的径向高度为H，L>0.1H；和/或，所述第二凹陷22的最大周向宽度为L，所述第二凸起21的径向高度为H，L>0.1H，进一步的，L>0.5H，以保证所述磁鼓与所述凸出部13、凹陷部14对应位置的磁场强度差值能够获得最佳检测分辨率，利于检测与利用。而可以理解的是，所述第一凸起11、第一凹陷12、第二凸起21、第二凹陷22的宽度L可以相等或者不相等，凹陷的深度H可以相等或者不相等，依据实际需求设计即可。
在一些实施方式中，所述第一凸起11、第一凹陷12以及所述第二凸起21、第二凹陷22皆通过机加工的方式形成，具体的例如采用激光加工方式，从而保证每个凸起及凹槽的尺寸精度，可以保证磁信号源在360°的均匀分布，能够有效克服磁环充磁过程中容易导致的N极和S极之间的无磁区模糊、变形和宽度不一致的缺陷，极大提高磁鼓的磁信号源质量，保证磁编码器的精度。
如果量两个磁环靠在一起的话，除非将检测探头(也即磁信号探头)刚好放置在两个磁环的接触缝隙位置，否则只要稍有偏差检测得到的磁信号就要么S极强N极弱，要么N极强S极弱，因此，在一些实施方式中，所述支撑环上还套装有隔磁环3，所述第一永磁环1与所述第二永磁环2对所述隔磁环3形成夹持，如此可以将磁信号探头位置偏差导致的磁信号偏差幅度大幅降低。所述隔磁环3的材质必须是磁的不良导体，例如铜、铝、塑料、橡胶等，此时，磁编码器具有的磁信号探头与所述隔磁环3相对设置，以能够获取到由所述第一永磁环1及第二永磁环2所形成的N/S交替磁信号。
研究发现，所述隔磁环3的轴向高度Da既与磁环在半径方向的厚度(即径向厚度ΔR)有关，也与磁环在轴向的高度(也即第一永磁环1Db及第二永磁环2的轴向高度Dc)有关，但所述隔磁环3的轴向高度Da越大在所述隔磁环3处检测到的磁信号越弱，所以所述隔磁环3的轴向高度不能太大，但正如前面所说，如果能保证磁性探头的位置绝对正确，即使没有所述隔磁环3也是可以的，而事实上，在实际实施过程中，这一位置难以得到可靠保证，因此， 在一些实施方式中，设计所述第一永磁环1与所述第二永磁环2的径向厚度相等且皆为△R，Da＜3(Db+Dc+△R)，最好的，Da＜2(Db+Dc+△R)，如此既能够保证磁性探头的位置的便利确定又能够保证检测信号的准确可靠。如果Da>3(Db+Dc+△R)，每个磁环的磁力线就可能会形成独立回路，则要么在两个磁环之间就检测不到N/S交替出现的磁信号要么检测到的N/S交替出现的磁信号强度不够，导致磁编码器精度降低。
在一些实施方式中，所述磁鼓还包括第三永磁环4(如图17所示)，所述第三永磁环4的外环壁上具有沿其轴向交替的N极及S极，能够使所述磁鼓的输出磁信号类型进一步丰富，有利于磁编码器芯片对此信号的综合处理后进一步提升控制精度。而可以理解的，所述支撑环的外圆周面上还可以套装于更多的永磁环，以进一步丰富所述磁鼓磁信号的输出类型。
所述支撑环的内侧环壁连接旋转轴，此时，所述支撑环的内侧环壁可以加工形成必要的连接结构，例如键槽(可以为花键、平键)，使磁鼓拆卸更加方便。
在一些实施方式中，在所述支撑环的任一径向平面上投影，所述第一凸起11和/或第二凸起21的形状为矩形、等腰梯形、等腰三角形、圆弧形中的一种，需要说明的是，所述第一凸起11、第二凸起21的具体形状本发明不做特别限定，但其无论是采用何种具体的形状，多个所述第一凸起11、第二凸起21皆应该关于所述磁鼓的轴心呈中心对称结构，以满足其作为编码器的磁信号源的需求。
在一些实施方式中，所述永磁体磁环本体1为辐射取向磁环或者单极充磁特征的各向同性磁环。
在一些实施方式中，所述辐射取向磁环采用钕铁硼、钐钴、铝镍钴、铁氧体中的至少一种制作形成，也即所述辐射取向磁环可以为单一的材料制作，亦可以采用多种材料复合而成。所述单极充磁特征的各向同性磁环采用钕铁硼、钐钴永磁体中的至少一种制作形成。
根据本发明的实施例，还提供一种磁编码器，包括上述的磁鼓。可以理解的，所述磁编码器还包括所述磁阻传感器以及相应的信号处理电路板(也即磁编码器芯片)，此部分作为磁编码器的常规技术，此处不做赘述。
本领域的技术人员容易理解的是，在不冲突的前提下，上述各有利方式可以自由地组合、叠加。
以上仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的 精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。以上仅是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明技术原理的前提下，还可以做出若干改进和变型，这些改进和变型也应视为本发明的保护范围。

Claims (10)

  1. 一种磁鼓，其特征在于，包括支撑环以及套装于所述支撑环外圆周侧的第一永磁环(1)、第二永磁环(2)，所述第一永磁环(1)与所述第二永磁环(2)沿所述支撑环的轴向依次设置，所述第一永磁环(1)及所述第二永磁环(2)皆为单极磁环且极性相反，所述第一永磁环(1)的外圆周壁上构造有沿其周向交替的第一凸起(11)、第一凹陷(12)，所述第二永磁环(2)的外圆周壁上构造有沿其周向交替的第二凸起(21)、第二凹陷(22)。
  2. 根据权利要求1所述的磁鼓，其特征在于，磁编码器具有的磁信号探头与所述第一永磁环(1)与所述第二永磁环(2)之间形成的圆周配合缝隙相对设置，以能够获取到由所述第一永磁环(1)及第二永磁环(2)所形成的N/S交替磁信号；或者，磁编码器具有的磁信号探头分别与所述第一永磁环(1)、所述第二永磁环(2)的外圆周壁相对设置，以能够分别获取到所述第一永磁环(1)、第二永磁环(2)所形成的N极磁信号及S极磁信号，并基于获取的所述N极磁信号及S极磁信号进行数据处理得到N/S交替磁信号。
  3. 根据权利要求1所述的磁鼓，其特征在于，沿着所述磁鼓的轴向，所述第一凸起(11)与所述第二凹陷(22)形成交替，所述第一凹陷(12)与所述第二凸起(21)形成交替。
  4. 根据权利要求1所述的磁鼓，其特征在于，所述第一凸起(11)、第一凹陷(12)以及所述第二凸起(21)、第二凹陷(22)皆通过机加工的方式形成。
  5. 根据权利要求1所述的磁鼓，其特征在于，所述支撑环上还套装有隔磁环(3)，所述第一永磁环(1)与所述第二永磁环(2)对所述隔磁环(3)形成夹持。
  6. 根据权利要求5所述的磁鼓，其特征在于，磁编码器具有的磁信号探头与所述隔磁环(3)相对设置，以能够获取到由所述第一永磁环(1)及第二永磁环(2)所形成的N/S交替磁信号。
  7. 根据权利要求5所述的磁鼓，其特征在于，所述隔磁环(3)的轴向高度为Da，所述第一永磁环(1)的轴向高度为Db，所述第二永磁环(2)的轴向高度为Dc，所述第一永磁环(1)与所述第二永磁环(2)的径向厚度相等且皆为△R，Da＜3(Db+Dc+△R)。
  8. 根据权利要求7所述的磁鼓，其特征在于，Da＜2(Db+Dc+△R)。
  9. 根据权利要求1所述的磁鼓，其特征在于，还包括第三永磁环(4)，所 述第三永磁环(4)的外环壁上具有沿其轴向交替的N极及S极。
  10. 一种磁编码器，包括磁鼓，其特征在于，所述磁鼓为权利要求1至9中任一项所述的磁鼓。
PCT/CN2021/137089 2021-09-17 2021-12-10 磁鼓及具有其的磁编码器 WO2023040085A1 (zh)

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CN113155158A (zh) * 2021-05-13 2021-07-23 深圳市瑞达美磁业有限公司 磁鼓及具有其的磁编码器
CN216283555U (zh) * 2021-09-17 2022-04-12 深圳市瑞达美磁业有限公司 磁鼓及具有其的磁编码器

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* Cited by examiner, † Cited by third party
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US4998084A (en) * 1989-01-24 1991-03-05 The Torrington Company Multipolar magnetic ring
DE102005061347A1 (de) * 2005-12-20 2007-06-21 Sensitec Gmbh Anordnung zur Messung des absoluten Drehwinkels einer Welle
CN104136284A (zh) * 2012-02-01 2014-11-05 法雷奥系统公司 用于确定电马达的轴的角位置的装置，和具有用于确定角位置的装置的风挡擦拭器马达
US20150253153A1 (en) * 2014-03-07 2015-09-10 Jeffrey R. Smithanik Variable Reluctance Resolve-Encoder
US20170138761A1 (en) * 2015-11-18 2017-05-18 National Tsing Hua University Ring magnetic encoder, manufacturing device for ring magnetic encoder, rotary shaft offset detecting method, and human-machine interface device thereof
TWI662255B (zh) * 2018-07-25 2019-06-11 大銀微系統股份有限公司 量測旋轉軸偏擺的磁性編碼器及其裝置
CN113155158A (zh) * 2021-05-13 2021-07-23 深圳市瑞达美磁业有限公司 磁鼓及具有其的磁编码器
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