Magnetic angle measuring device

Abstract

To provide a magnetic angle measuring device by which precise, reliable operational behavior can be achieved and which is economical to produce.SOLUTION: The angle measuring device includes a first component group (1) and a second component group (2; 2'). The first component group and the second component group are arranged so as to be rotatable relative to one another about an axis (A). The first component group includes a position measuring device (1.5) and, in some cases, a domain-wall memory (1.1). The position measuring device is mounted on a circuit board (1.2). The second component group has a magnet arrangement. The magnet arrangement includes a plurality of magnets (2.1-2.8) arranged in a form of a Halbach array around an axis (A) or configured as a Halbach cylinder (2.9'). The position measuring device can detect an angular position upon a rotation of the magnet arrangement relative to the circuit board.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The invention relates to a magnetic angle measurement device according to claim 1.

[0002] Magnetic angle measuring devices are used, for example, as rotary encoders based on magnetic scanning to measure the angular position of two machine parts that can rotate relative to one another.

[0003] Often, such measuring devices or measuring instruments for electric drives are used to measure the relative movement or relative position of corresponding mechanical parts, the position values ​​generated then being supplied via corresponding interface devices to subsequent electronics that control the drives.

[0004] In many applications of angle measuring devices, it is important to know and non-volatilely store at least the number of rotations or the approximate position, even in the event of a temporary power outage. For this purpose, so-called multi-turn angle measuring devices are often used, which allow the measurement of the absolute position over a large number of rotations.

[0005] Patent document 1 describes a magnetic measuring device for measuring angular position, which has a domain wall memory as a multi-turn sensor, the domain wall of which can be moved by one or two permanent magnets that can rotate relative to the domain wall memory. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] German Patent Application Publication No. 102022106330 Summary of the Invention [Problem to be solved by the invention]

[0007] SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic angle measuring device that can achieve precise and reliable operating behavior and that can be manufactured inexpensively. [Means for solving the problem]

[0008] According to the invention, this problem is solved by the features of claim 1.

[0009] According to the invention, the magnetic angle measurement device includes a first component group and a second component group, which are rotatably arranged relative to one another in a measurement direction or a circumferential direction. The first component group includes a position detector mounted on a circuit board. The second component group includes a magnet array. The magnet array includes a plurality of magnets arranged as a Halbach array around an axis. Alternatively, the magnet array can be configured as a Halbach cylinder. Furthermore, the magnet array is spaced apart from the position detector so that the relative angular position between the first component group and the second component group can be detected by the position detector when the magnet array rotates relative to the circuit board.

[0010] In particular, the position detector may be arranged axially offset relative to the magnet array.Alternatively or additionally, the circuit board may be arranged axially offset relative to the magnet array.

[0011] Advantageously, the position detector is cut or penetrated by the axis. Often, an arrangement in which the (rotational) axis intersects the position detector is referred to as an "on-axis" arrangement.

[0012] The magnetization direction can be understood as the direction of the line connecting the south and north poles of a magnet. The magnetization angle is the angle between parallel lines and the magnetization direction at a specific point on the circumference or at a specific angle in the circumference.

[0013] Advantageously, the magnet arrangement is configured such that the magnetization at a first circumferential angle is oriented to have a first magnetization angle, and at a second circumferential angle, the magnetization has a second magnetization angle, where the first magnetization angle is rotated relative to the second magnetization angle by twice the difference between the first and second circumferential angles.

[0014] The Halbach cylinder may be constructed as a single piece or may be constructed from multiple segments.

[0015] In a further embodiment of the invention, the first component group includes a domain wall memory that is also mounted on the circuit board such that as the magnet array rotates relative to the circuit board, rotations can be counted by the domain wall memory. In this embodiment, the magnet array functions not only as an angular scale to more precisely measure the relative angular position between the first and second component groups, but also to count rotations by the domain wall memory.

[0016] Advantageously, the first component group comprises, inter alia, a housing for shielding interference fields, which housing is configured to surround the magnet array circumferentially or entirely, and advantageously also surround the position detector and / or domain wall memory circumferentially. Furthermore, the housing can be configured to also surround the magnet array and / or the position detector and / or the domain wall memory in the axial direction, which can increase the effectiveness of shielding interference fields under appropriate boundary conditions. In particular, the housing may surround the second component group.

[0017] In a further embodiment of the invention, an electrical connection is attached directly to the circuit board, in particular passing through the housing, so that the angle measuring device can be electrically connected to further electronic equipment by means of a plug connection, in particular by direct contact on the circuit board.

[0018] Advantageously, the position detector comprises at least one magnetoresistive element, for example based on the AMR, GMR or TMR effect. Alternatively or additionally, the position detector may comprise at least one Hall element. Therefore, since scanning is based on a magnetic principle, the angle measuring device is called a magnetic angle measuring device.

[0019] Advantageously, at least two of the magnets arranged as a Halbach array are identical or identically configured, and the identical magnets can be rotated relative to one another, particularly around an imaginary line extending parallel to an axis along which the first group of elements is rotatable relative to the second group of elements.

[0020] The Halbach cylinder and / or magnet can be manufactured by a sintering method or a casting method. Alternatively, the material of the Halbach cylinder and / or magnet includes a synthetic resin with a magnetizable filler. In particular, the magnet and / or Halbach cylinder can be manufactured by a pressing method or an injection molding method.

[0021] A domain wall memory comprises domain wall conductors extending in a plane. Basically, domain wall conductors configured as open spirals and domain wall conductors with closed extensions are known.

[0022] The domain wall conductor is made of a magnetizable material and is configured in the context of the present invention, in particular, as at least one conductor track, conductor path or nanowire. Information can be stored in the domain wall conductor in the form of oppositely magnetized regions (domains). The domains are separated along the conductor track by so-called domain walls, which can be shifted by a magnetic field, thereby changing the position of the domains.

[0023] Advantageously, the domain wall memory comprises a particularly flat substrate, the domain wall conductors being configured as conductor tracks on the substrate, the surface on which the domain wall conductors extend being flat.

[0024] The structural width of the domain wall conductor is typically less than 500 nm, often less than 300 nm, and the thickness or layer thickness of the domain wall conductor is less than 60 nm. The domain wall memory may have multiple domain wall conductors.

[0025] Furthermore, the domain wall memory includes a read element, which can measure the local magnetization state of the domain wall conductor (at each position of the read element). Thus, the read element can measure the magnetization state of each domain wall conductor. The read element is arranged at a fixed position relative to the domain wall conductor. For example, a GMR sensor or a TMR sensor can be used as the read element.

[0026] Advantageous configurations of the invention can be read from the dependent claims.

[0027] Further details and advantages of the angle measuring device according to the invention will become apparent from the following description of an exemplary embodiment based on the accompanying drawings. [Brief explanation of the drawings]

[0028] [Figure 1] 1 shows a cross-sectional view of an angle measurement device. [Figure 2] 10 shows a top view of the magnets of the second component group. [Figure 3] 1 shows a top view of a domain wall conductor. [Figure 4] 10 shows a top view of a Halbach cylinder of a second component group according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0029] 1 shows an angle measuring device comprising a first component group 1 and a second component group 2, where the component groups 1 and 2 are arranged rotatably relative to one another about an axis A. The first component group comprises a circuit board 1.2, a position detector 1.5, a domain wall memory 1.1, an electrical connection 1.3, and a housing 1.4.

[0030] In a first embodiment, the second component group 2 includes a carrier body 2.9 having a magnet arrangement on its front side, which includes a plurality of magnets 2.1 to 2.8, as shown in Fig. 2. The magnets are embedded in the carrier body 2.9, which has a central hole with a shoulder that can accommodate a fixing screw, which is preferably non-magnetic. The carrier body 2.9 can be made, for example, from a synthetic resin material.

[0031] The magnets 2.1 to 2.8 are arranged according to a Halbach array. In the example shown, eight identical rectangular magnets 2.1 to 2.8 are staggered around the circumference or arranged at different circumferential angles φ, whereby this arrangement corresponds to a so-called k = 2 Halbach array. In Figure 2, the magnetization directions are indicated by arrows on the circumference. The magnetization direction can be understood as the direction of the connecting lines of the south and north poles of the magnets. The magnetization directions are summarized in the table below: [Table 1] As shown in the table, the magnetization angle γ, which is the angle between the arrow direction of each magnet 2.1-2.8 and a line that is always aligned in the same way, varies along the circumference twice as fast (k = 2) as the circumferential angle φ, which defines the angular position of magnets 2.1-2.8 along the circumference. In this example, magnets 2.1-2.8 are each offset by 45° (Δφ = 45°) on the circumference. At Δφ = 45°, the magnetization angle changes by Δγ = 90°. Here, the general rule "Δγ = 2 Δφ" applies.

[0032] For example, a first circumferential angle φ1=0° results in a first magnetization angle γ1=270°. If one moves further along the circumferential line to a second circumferential angle φ2, for example φ2=90°, then a second magnetization angle γ2=90° results. Next, the first magnetization angle γ1 is rotated by an angle Δγ=180° relative to the second magnetization angle γ2, making the difference between the first circumferential angle φ1 and the second circumferential angle φ2 90°, i.e., Δφ=90°.

[0033] 1, the first component group 1 comprises a domain wall memory 1.1 and a position detector 1.5 in the same package as the domain wall memory 1.1. This position detector 1.5 can scan the magnetic field of the magnet array and convert it into an electrical signal containing information about the angular position within one revolution. The position detector 1.5 may include a magnetoresistive element or, for example, a Hall element.

[0034] According to FIG. 3, the domain wall memory 1.1 comprises a domain wall conductor 1.11 and a substrate 1.12, where the domain wall conductor 1.11 is applied in the form of a conductor track on the substrate 1.12 and extends in (or on) a first plane XY. The domain wall conductor 1.11 comprises a domain wall generator 1.111 at one end. In the example shown, the substrate 1.12 comprises a mechanically supporting silicon layer, is configured flat, and the domain wall conductor 1.11 may be part of a CMOS chip. Alternatively, the substrate may comprise a glass layer. The domain wall conductor 1.11 comprises a soft magnetic material, for example, a Ni-Fe alloy. The domain wall conductor 1.11 may be configured as an open spiral, as shown in FIG. 3, or may have a closed elongated form.

[0035] During operation of the angle measurement device, the first component group 1 and the second component group 2 are positioned opposite each other. In this embodiment, the first component group 1 can operate as a stator and the second component group 2 can operate as a rotor.

[0036] The magnet array is scanned by a position detector 1.5, which provides an electrical signal carrying position information that can be transmitted via an electrical coupling 1.3 and then further via a cable to other electronic equipment.

[0037] The domain wall memory 1.1 is used to ensure multi-turn functionality, ie the ability to count multiple turns or passes.

[0038] With each quarter turn of the second component group 2, one or more domain walls move further. The magnetization direction in the domain wall conductor 1.11 section, and thus the position of the domain wall, can be detected by a read element integrated into the domain wall memory 1.1. In this way, counting of rotations or storage of rotation information in the angle measurement device is possible even when auxiliary energy is unavailable. This is important, for example, when a shaft is moved by gravity during a power failure. Furthermore, the domain wall shifts depending on the direction of rotation, so that the domain wall memory 1.1 can be used reliably in applications that allow two directions of rotation.

[0039] Scanning of the magnetic field by the position detector 1.5 (not shown in detail) provides a relatively accurate measurement of the angular position within one revolution. For absolute measurement of the angular position over several revolutions (multi-turn functionality), the angular position determined by the position detector 1.5 (fine position) must be synchronized with the rotational information (coarse position) in the domain wall memory 1.1.

[0040] According to the embodiment shown in Figure 4, the second component group 2' uses a one-piece Halbach cylinder 2.9' instead of the discrete magnets 2.1 to 2.8. This is relatively complex and, in particular, is anisotropically magnetized, so that its magnetization vector is given by the following equation:

number

number

[0041] In the case of a Halbach array with k=2, the following equation:

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[0042] In FIG. 4, the magnetization direction is indicated by the arrows on the circumference.

[0043] Thus, the magnet arrangement is configured such that the first magnetization angle γ1 is rotated relative to the second magnetization angle γ2 by an angle Δγ that is twice greater than the difference Δφ between the first and second circumferential angles φ1 and φ2, as given by the following equation: 2·Δφ=γ1-γ2=Δγ.

Claims

1. An angle measuring device comprising a first group of components (1) and a second group of components (2; 2'), The component groups (1, 2; 2') are arranged to be rotatable relative to each other about an axis (A), the first component group (1) comprises a position detector (1.5), the position detector (1.5) being mounted on a circuit board; a second group of components (2;2') comprising a magnet arrangement; a) the magnet arrangement comprises a plurality of magnets (2.1-2.8), said plurality of magnets being arranged in a Halbach array around an axis (A); or b) the magnet arrangement is configured as a Halbach cylinder (2.9'); The magnet array is spaced apart relative to the position detector (1.5) such that an angular position is detectable by the position detector (1.5) upon rotation of the magnet array relative to the circuit board (1.2). Angle measuring device.

2. the magnet arrangement is configured such that the magnetization at a first circumferential angle (φ1) has a first magnetization angle (γ1) and the magnetization at a second circumferential angle (φ2) has a second magnetization angle (γ2); The first magnetization angle is rotated relative to the second magnetization angle (γ2) by an angle (Δγ) that is twice the difference (Δφ) between the first circumferential angle (φ1) and the second circumferential angle (φ2).

2. An angle measuring device according to claim 1.

3. 3. An angle measuring device according to claim 1 or 2, wherein the first component group (1) comprises a domain wall memory (1.1), by means of which rotations of the magnet arrangement relative to the domain wall memory (1.1) can be counted.

4. 4. An angle measuring device according to claim 3, wherein the domain wall memory (1.1) is mounted on the circuit board (1.2).

5. 5. An angle measuring device according to claim 1, wherein the first component group (1) comprises a housing (1.4) configured to surround the position detector (1.5) and the magnet arrangement around a circumference for shielding them from interference fields.

6. 6. An angle measuring device according to claim 5, wherein the housing (1.4) surrounds the domain wall memory (1.1) circumferentially to shield it from interference fields.

7. Angle measuring device according to any one of claims 1 to 6, characterized in that electrical connections are attached to the circuit board (1.2).

8. Angle measuring device according to any one of claims 1 to 7, wherein the position detector (1.5) comprises at least one magnetoresistive element or a Hall element.

9. 9. An angle measuring device according to claim 1, wherein at least some of the magnets (2.1-2.8) arranged as a Halbach array are each configured as identical magnets.

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