English:
[0001] Embodiments are generally related to sensor methods and systems. Embodiments are also related to magnetic sensors. Embodiments are additionally related to Anisotropic Magnetoresistive (AMR) array magnetic designs for improved sensor flexibility and improved air gap performance.
[0002] Magnetoresistive (MR) technology can be utilized in a variety of commercial, consumer, and industrial detection applications. Anisotropic Magnetoresistance (AMR) is the property of a material in which the electrical resistance can change depending on the angle between the direction of electrical current and orientation of magnetic field is observed. AMR array position sensors yield a very accurate signal with respect to the position of a magnet. In conventional MR systems, for example, a device may be provided for determining the position of a member movable along a path. The device includes a magnet attached to the movable member and an array of AMR sensors located adjacent the path. As the magnet approaches, passes, and moves away from a sensor, the sensor provides a varying output signal, which can be represented by a single characteristic curve that is representative of any of the sensors.
[0004] FIG. 1A and 1 B illustrates a prior art AMR position sensing system 100. The AMR position sensing system 100 generally includes a magnet 110 and an array of AMR position sensors 130 to sense the relative position of the magnet 110 within the array of AMR position sensors 130. The magnet 1 10 must be positioned such that the magnetic flux lines as indicated by arrow 120 of the magnet 110 are in the same plane of the AMR position sensors 130. The magnet 1 10 generates magnetic flux lines 120 while moving in the direction as indicated by arrow 140. If the air gap 160, the distance between the magnet 1 10 and the AMR position sensors 130, is changed significantly after calibration, the performance of the AMR position sensors 130 also changes. FIG 1 B illustrates the magnetic flux lines 120 in different direction when the magnet moves in the same plane of the AMR position sensors 130 in the direction as indicated by arrow 140.
[0005] FIG. 2 illustrates two AMR bridge signals 200 and 210 obtained from the prior art AMR position sensing system 100 as the magnet 110 moves and passes the AMR position sensors 130. The bridge signals 200 and 210 can be generated as the magnet 110 moves and passes through the AMR position sensors 130. The peaks 220 and 230 correspond to the position when the magnetic flux lines 120 are perpendicular to half the AMR sensor runners 135 and parallel to the others in the AMR position sensors 130. The position at which the magnetic flux lines 120 are parallel or perpendicular to the AMR sensor runners 135 changes with respect to the changes in the air gap 160, which in turn changes the bridge signal 200 generated from the AMR position sensors 130 respect of position. The problem associated with such prior art position sensing system 100 is that as the distance between the AMR position sensors 130 and the magnet 110 changes, the signal changes decreasing repeatability of the sensor. Hence, the overall performance of the AMR position sensors decreases.
[0006] Based on the foregoing, it is believed that a need exists for an improved AMR array magnetic design for improved sensor flexibility and improved air gap performance as described in greater detail herein.
[0007] The following summary is provided to facilitate an understanding of some of the innovative features unique to the embodiments disclosed and is not intended to be a full description. A full appreciation of the various aspects of the embodiments can be gained by taking the entire specification, claims, drawings, and abstract as a whole.
[0009] It is another aspect of the present invention to provide an improved AMR position sensing system.
[0010] It is a further aspect of the present invention to provide an improved AMR array magnetic position sensing system for improved sensor flexibility and improved air gap performance.
[0011] The aforementioned aspects and other objectives and advantages can now be achieved as described herein. An AMR array magnetic position sensing system for improved sensor flexibility and improved air gap performance is disclosed. A pair of magnets can be enclosed in a magnet carrier that moves along a path and located above an array of AMR position sensors. The magnets are generally magnetized through the length of the magnets. The AMR position sensors can come into contact with the uniform magnetic flux lines to sense a change in linear and angular position associated with the magnet carrier. The output signal generated by the AMR position sensors have less susceptibility to variations in air gap as the angles of the magnetic flux lines generated by the magnets are not changing with air gap variation.
[0012] The AMR position sensors can be located external to the two magnets, such that the sensor comes into contact with the uniform magnetic flux lines to sense a change in angular and linear position associated with the rotatable base. The AMR array position sensors can sense linear and rotary position of the magnets while the magnet carrier is moving in the linear or rotary magnetized direction to efficiently sense the position of the moving magnet carrier. Such an AMR array magnetic sensor design can improve the performance of the AMR array sensors with respect to changes of air gap.
[0013] The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the embodiments and, together with the detailed description, serve to explain the embodiments disclosed herein.
[0014] FIG. 1 A and 1 B illustrates a prior art AMR position sensing system;
[0015] FIG. 2 illustrates a graphical representation of the bridge signals obtained from the prior art AMR position sensing system;
[0016] FIG. 3 illustrates a perspective view of an AMR position sensing system, in accordance with a preferred embodiment;
[0017] FIG. 4 illustrates a top view of the AMR position sensing system, in accordance with a preferred embodiment;
[0019] FIG. 6 illustrates a perspective view of the AMR position sensing system for linear position sensing, in accordance with a preferred embodiment;
[0020] FIG. 7 illustrates a perspective view of the AMR position sensing system for rotary position sensing, in accordance with a preferred embodiment; and
[0021] FIG. 8 illustrates a detailed flow chart of operations illustrating logical operational steps of a method for designing the AMR position sensing system for improved sensor flexibility and improved air gap performance, which can be implemented in accordance with a preferred embodiment.
[0022] The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment and are not intended to limit the scope thereof.
[0023] FIG. 3 illustrates a perspective view of an AMR position sensing system 300, in accordance with a preferred embodiment. The AMR position sensing system 300 generally includes a magnet carrier 310, which holds two magnets 320 and 325. The magnets 320 and 325 are generally magnetized through the length of the magnets to create uniform magnetic flux lines 330 thereof. The AMR position sensing system 300 also includes an array of AMR position sensors 340 with AMR runners 345 located respectively external to first and second magnets 320 and 325. The magnets 320 and 325 enclosed in the magnet carrier 310 moves along a path 350 and generally located centrally above the array of AMR position sensors 340. Note that as utilized herein, the term "above" can refer to both vertical and horizontal positions. The AMR position sensors 340 thus come into contact with the uniform magnetic flux lines 330 to sense a change in position associated with the magnet carrier 310.
[0024] The magnetic flux lines 330 are depicted in FIG. 3 between the magnets 320 and 325. The AMR position sensors 340 can therefore be configured as a single anisotropic magnetoresistive (AMR) permalloy sensing bridge (not shown) configured from four thin-film resistors located at a fixed point from magnets 320 and 325 to provide a sinusoidal voltage signal as the resultant flux density vector varies with magnet travel. A magnet travel position can then be determined from the sinusoidal signal voltage curve. The AMR effect changes a resistance of a magneto-resistive effect element in proportion to a square of a cosine of an angle formed between the magnetization of the element and the direction in which a sense current that flows through the element is conducted. AMR occurs in certain ferrous materials such as permalloy and can be applied as a thin film to become a resistive element.
[0025] FIG. 4 illustrates a top view of the AMR position sensing system 300, in accordance with the preferred embodiment. Note that in FIGS. 3-4, identical or similar parts are generally indicated by identical reference numerals. The AMR position sensing system 300 generally includes the magnet carrier 310 and the array of AMR position sensors 340. The AMR position sensors 340 comes into contact with the uniform magnetic flux lines 330 to sense a change in linear and angular position associated with the magnet carrier 310. The array of AMR position sensors 340 can provide output signals as the magnet carrier 310 passes and moves away from each of the AMR sensors in the array 340. The output signals have less susceptibility to variations in air gap 355 between the magnet carrier 310 and the AMR position sensors 340 as the angles of the flux lines 330 are not changing with air gap variation.
[0026] FIG. 5 illustrates a graphical representation of two bridge signals 400 obtained from the AMR position sensing system 300, in accordance with the preferred embodiment. The bridge signals 400 can be generated as the magnets 320 and 325 moves and passes over the AMR position sensors 340. The bridge signals 400 comprise AMR sensor signals corresponding to the magnet carrier 310 position moving in the linear direction 350. The bridge signals 400 have less susceptibility to variations in air gap 355 as the angles of the flux lines 330 are not changing with the variation of the air gap 355.
[0027] FIG. 6 illustrates a perspective view of an AMR position sensing system 500 for linear position sensing, in accordance with a preferred embodiment. The AMR position sensors 340 can be positioned linearly and can be located below the two magnets 320 and 325 associated with the magnet carrier 310, such that the sensors 510 comes into contact with the magnetic flux lines 330 to sense a change in linear position associated with the magnet carrier 310. The linear array of AMR position sensors 510 can be utilized to sense the position of the magnet carrier 310 while moving in the linear direction 515.
[0028] FIG. 7 illustrates a perspective view of the AMR position sensing system 550 for rotary position sensing, in accordance with a preferred embodiment. The AMR rotary position sensors 520 can be located below the two magnets 320 and 325 associated with the magnet carrier 310, such that the sensors 520 comes into contact with the uniform magnetic field 330 to sense a change in rotary position associated with the magnet carrier 310. The rotary array of AMR position sensors 520 can be utilized to sense the position of the magnet carrier 310 while moving in the rotary magnetized direction 525.
[0029] FIG. 8 illustrates a detailed flow chart of operations illustrating logical operational steps of a method 600 for designing the AMR position sensing system 300 for improved sensor flexibility and improved air gap performance, which can be implemented in accordance with a preferred embodiment. A pair of magnets 320 and 325 can be located in a magnet carrier 310, as illustrated at block 610. Next, as depicted at block 620, the AMR position sensors 340 can be located below the magnet carrier 310. The magnet carrier 310 can then be moved and passed over the AMR array sensors 340, as shown at block 630. Thereafter, magnetic flux lines 330 between the pair of magnets 320 and 325 can be generated, as illustrated at block 640.
[0030] The change in angular and/or linear position can then be sensed utilizing the AMR position sensors 340, as illustrated in block 650, and the signals generated by the sensors 340 have less susceptibility to variations in air gap 355 as the angles of the flux lines 330 are not changing with air gap variation. It is believed that by utilizing the AMR position sensing system 300 described herein, the sensor flexibility can be increased significantly by placing the magnet carrier 310 over the AMR position sensors 340. The performance of the AMR position sensors 340 with respect to changes of air gap 355 can also be improved.

中文:
[0001]实施例一般涉及传感器方法和系统。实施例还涉及磁性传感器。实施例另外涉及用于改善的传感器灵活性和改善的气隙性能的各向异性磁阻(AMR)阵列。
[0002]在多种商业、消费装置、和工业检测应用中利用磁阻(MR)技术。各向异性磁阻(AMR)是一种材料的性质,其中,电阻能够根据电流方向与观察到的磁场取向之间的角而变。AMR阵列位置传感器提供关于磁铁位置的非常准确的信号。在常规MR系统中,例如,可以提供用于确定可沿着一个路径活动的部件的位置的设备。该设备包括附着于活动部件的磁铁和位于路径附近的AMR传感器阵列。随着磁铁接近、通过、和远离传感器,传感器提供变化的输出信号,可以用表示任何传感器的单个特性曲线来表示该变化的输出信号。
[0004]图1A和1B举例说明现有技术AMR位置感测系统100。AMR位置感测系统100一般包括磁铁110和AMR位置传感器阵列130以感测磁铁110在AMR位置传感器阵列130内的相对位置。磁铁110必须被定位为使得磁铁110的如箭头120所指示的磁通线在AMR位置传感器130的同一平面内。磁铁110在沿着如箭头140所指示的方向移动的同时产生磁通线120。如果在校准之后,气隙160、磁铁110与AMR位置传感器130之间的距离显著地改变,则AMR位置传感器130的性能也改变。图1B举例说明磁铁沿着如箭头140所指示的方向在AMR位置传感器130的统一平面内移动时的沿不同方向的磁通线120。
[0005]图2举例说明随着磁铁110移动并通过AMR位置传感器130而从现有技术AMR位置感测系统100获得的两个AMR桥信号200和210。桥信号200和210可以随着磁铁110移动并穿过AMR位置传感器130而生成。峰值220和230对应当磁通线120垂直于AMR传感器滑槽(runner)136的一半且在AMR位置传感器130中与其它的平行时的位置。磁通线120平行于或垂直于AMR传感器滑槽135的位置相对于气隙160的变化而变,气隙160的变化又在位置方面改变从AMR位置传感器130生成的桥信号200。与此类现有技术位置感测系统100相关联的问题是随着AMR位置传感器130和磁铁110之间的距离改变,信号改变,降低传感器的可重复性。因此,AMR位置传感器的总体性能下降。
[0006]基于前述内容,应相信存在对如本文中更详细地描述的用于改善的传感器灵活性和改善的气隙性能的改善的MAR阵列磁性设计的需要。
[0007]提供以下概要是为了促进对只有所公开的实施例才有的某些创新特征的理解且其并不意图是详尽的描述。可以通过将整个说明书、权利要求、附图和摘要视为一个整体来获得实施例的各种方面的全面认识。
[0009]本发明的另一方面是提供一种改善的AMR位置感测系统。
[0010]本发明的另一方面是提供一种用于改善的传感器灵活性和改善的气隙性能的改善的AMR阵列磁性位置感测系统。
[0011]现在可以如上所述地实现上述方面及其它目的和优点。公开了一种用于改善的传感器灵活性和改善的气隙性能的AMR阵列磁性位置感测系统。可以将一对磁铁封闭在沿着路径移动且位于AMR位置传感器阵列之上的磁铁载体中。该磁铁一般遍及磁铁的整个长度磁化。AMR位置传感器可以与均匀的磁通线接触以感测与磁铁载体相关联的直线和角位置的变化。由AMR位置传感器生成的输出信号对气隙的变化具有较低的敏感度,因为由磁铁产生的磁通线的角不随着气隙变化而变。
[0012]AMR位置传感器可位于两个磁铁的外部,使得传感器与均匀磁通线接触以感测与可旋转底座相关联的角和直线位置的变化。AMR阵列位置传感器可以感测磁铁的直线和旋转位置,而磁铁载体沿着直线或旋转磁化方向移动以高效地感测移动的磁铁载体的位置。此类AMR阵列磁铁传感器设计能够相对于气隙的变化改善AMR阵列传感器的性能。
[0013]附图用于进一步举例说明实施例并连同详细说明一起用于解释本文公开的实施例,在所述附图中,相同的参考标号在单独视图中自始至终指示相同或功能上类似的元件且其结合到本说明书中并构成其一部分。
[0014]图1A和1B举例说明现有技术AMR位置感测系统;
[0015]图2举例说明从现有技术AMR位置感测系统获得的桥信号的图形表示 ;
[0016]图3举例说明依照优选实施例的AMR位置感测系统的透视图;
[0017]图4举例说明依照优选实施例的AMR位置感测系统的顶视图;
[0019]图6举例说明依照优选实施例的用于直线位置感测的AMR位置感测系统的透视图;
[0020]图7举例说明依照优选实施例的用于旋转位置感测的AMR位置感测系统的透视图;以及
[0021]图8举例说明操作的详细流程图,该操作举例说明能够依照优选实施例实现的用于设计用于改善的传感器灵活性和改善的气隙性能的AMR位置感测系统的方法的逻辑操作步骤。
[0022]在这些非限制性示例中讨论的特定值和配置可以改变且仅仅是为了举例说明至少一个实施例而引用的,并且并不意图限制其范围。
[0023]图3举例说明依照优选实施例的AMR位置感测系统300的透视图。AMR位置感测系统300一般包括保持两个磁铁320和325的磁铁载体310。磁铁320和325一般遍及磁铁的长度磁化已产生其均匀磁通线330。AMR位置感测系统300还包括AMR位置传感器340阵列,其具有分别位于第一和第二磁铁320和325外部的AMR滑槽345。封闭在磁铁载体310中的磁铁320和325沿着路径350移动且一般在中心处位于AMR位置传感器阵列340之上。请注意,本文所使用的术语“之上”可以指的是垂直和水平位置两者。因此,AMR位置传感器340与均匀磁通线330接触以感测与磁铁载体310相关联的位置变化。
[0024]在图3中描绘了磁铁320和325之间的磁通线330。因此,可以将AMR位置传感器340配置为由位于距离磁铁320和325的固定点处的四个薄膜电阻器配置的单个各向异性磁阻(AMR)透磁合金感测桥(未示出)以在结果得到的磁通密度矢量随着磁铁的行进而变时提供正弦电压信号。然后,可以根据正弦信号电压曲线来确定磁铁行进位置。AMR效应与在元件的磁化与传导流过元件的感测电流的方向之间形成的角的余弦的平方成比例地改变磁电阻效应元件的电阻。AMR在诸如透磁合金的某些铁氧材料中发生,并且能够用作薄膜以变成电阻元件。
[0025]图4举例说明依照优选实施例的AMR位置感测系统300的顶视图。请注意,在图3~4中,一般用相同的参考标号来指示相同或类似部分。AMR位置感测系统300一般包括磁铁载体310和AMR位置传感器阵列340。AMR位置传感器340与均匀磁通线330接触以感测与磁铁载体310相关联的直线和角位置的变化。AMR位置传感器阵列340能够随着磁铁载体310通过并远离阵列340中的每个AMR传感器而提供输出信号。该输出信号对磁铁载体310与AMR位置传感器340之间的气隙355的变化具有较低的敏感度,因为磁通线330的角不随着气隙变化而变。
[0026]图5举例说明从依照优选实施例的AMR位置感测系统300获得的两个桥信号400的图形表示。桥信号400可以随着磁铁320和325移动并穿过AMR位置传感器340而生成。桥信号400包括与沿着直线方向350移动的磁铁载体310位置相对应的AMR传感器信号。桥信号400对气隙355的变化具有较低的敏感度,因为磁通线330的角不随着气隙355的变化而变。
[0027]图6举例说明依照优选实施例的用于直线位置感测的AMR位置感测系统500的透视图。 AMR位置传感器340可以直线地定位且可以位于与磁铁载体310相关联的两个磁铁320和325下面,使得传感器510与磁通线330接触以感测与磁铁载体310相关联的直线位置的变化。可以利用AMR位置传感器510的直线阵列在沿着直线方向515移动的同时感测磁铁载体310的位置。
[0028]图7举例说明依照优选实施例的用于旋转位置感测的AMR位置感测系统550的透视图。AMR旋转位置传感器520可以位于与磁铁载体310相关联的两个磁铁320和325下面,使得传感器520与均匀磁场330接触以感测与磁铁载体310相关联的旋转位置的变化。可以利用AMR位置传感器旋转阵列520以在沿着旋转磁化方向525移动的同时感测磁铁载体310的位置。
[0029]图8举例说明操作的详细流程图,该操作举例说明能够依照优选实施例实现的用于设计用于改善的传感器灵活性和改善的气隙性能的AMR位置感测系统300的方法600的逻辑操作步骤。如方框610处举例说明的,可以在磁铁载体310中放置一对磁铁320和325。接下来,如在方框620处所描绘的,AMR位置传感器340可以位于磁铁载体310下面。然后,如方框630处所示,磁铁载体310可以移动并通过AMR阵列传感器340。此后,如在方框640处举例说明的,可以在该对磁铁320和325之间产生磁通线330。
[0030]然后,如在方框650处举例说明的,可以利用AMR位置传感器340来感测角和/或直线位置的变化,并且由传感器340产生的信号对气隙355的变化具有较低的敏感度,因为磁通线330的角不随着气隙变化而变。应相信的是通过利用本文所述的AMR位置感测系统300,可以通过在AMR位置传感器340之上放置磁铁载体310来显著地增加传感器灵活性。还可以改善AMR位置传感器340相对于气隙355的变化的性能。