Inductive position measurement device

Abstract

To provide an inductive position measurement device that identifies an absolute relative position.SOLUTION: A scanning unit includes a first reception pattern path, has at least one reception conductor, and extends over at least a certain length (L). Further, the scanning unit includes a second reception pattern path, has at least one reception conductor, and extends over at least the same length (L). A scale part has a scale track, and is formed from a plurality of ribs and a plurality of gaps. The ribs have different widths (BS) in a first direction (X), or the gaps have different depths (HL) or different widths. (BL). A first signal (S1.1) having a first period length (P1.1) can be generated by the reception conductor of the first reception pattern path, and a second signal (S1.2) having a second period length (P1.2) can be generated by the reception conductor of the second reception pattern path, where n times the first period length is equal to m times the second period length, and n*P1.1=m*P1.2≤L (n and m are mutually prime) is satisfied.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inductive position measuring device according to claim 1 for specifying a relative position.

[0002] An inductive position measuring device is used, for example, as a measuring instrument for specifying the relative position of two members that can be displaced relative to each other. In an inductive position measuring device, excitation coils and reception coils are often formed, for example, in the form of conductor patterns, on a common circuit board that is usually multilayered. This unit may be called a scanning unit. There is a scale portion facing this scanning unit, and on it, for example, a plurality of ribs and a plurality of gaps are arranged as a scale structure. When an excitation current that changes alternately with time is applied to the excitation coil, a signal that depends on the relative position is generated in the reception coil while the scale portion and the scanning unit are in relative motion. These signals are then further processed by an analysis electronic circuit.

Background Art

[0003] Patent Document 1 describes an encoder for specifying an absolute relative position. In that description, the same number of bits are generated by a predetermined number of scanning units in order to determine the absolute position.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide an inductive position measuring device that enables an absolute relative position to be specified in a simple manner in a first direction extending along a reception pattern path.

Means for Solving the Problems

[0006] This problem is solved by the features of claim 1 in the present invention.

[0007] The induction-type position measuring device comprises a scanning unit and a scale unit, the scale unit being displaceable relative to the scanning unit or linearly along a certain first direction. The scanning unit comprises at least one excitation wire. Furthermore, the scanning unit comprises a first receiving pattern path, the receiving pattern path comprising at least one receiving wire, the receiving wire extending along a first direction in a first periodic pattern and extending over at least a certain length L. The scanning unit further comprises a second receiving pattern path, the receiving pattern path comprising at least one receiving wire, the receiving wire extending along a first direction in a second periodic pattern and extending over at least the same length L. The scale unit comprises a scale track, the scale track comprising a scale structure along a first direction, the scale structure being formed in particular from alternately arranged ribs and gaps. Here, a) These ribs have multiple different widths in the first direction, or b) Whether these gaps have multiple different depths or multiple different widths in the first direction At least one of the following: The position measuring device is configured such that the electromagnetic field generated by at least one excitation wire via a scale track is moduloable. A first signal with a first period length P1.1 can be generated by the receiving wire of the first receiving pattern path, and a second signal with a second period length P1.2 can be generated by the receiving wire of the second receiving pattern path. Here, n times the first period length P1.1 is equal to m times the second period length P1.2, m and n are relatively prime, and n times the first period length P1.1 or m times the second period length P1.2 is less than or equal to the above length L. Thus, the following holds:

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[0008] By using a position measuring device, the absolute position of the scale portion relative to the scanning portion can be detected using the receiving wires of the first receiving pattern path and the receiving wires of the second receiving pattern path, particularly in accordance with the principle of calipers (Nonius-Prinzip).

[0009] The first periodic pattern and / or the second periodic pattern may have a sinusoidal curve. The first receiving pattern path, in particular, comprises at least one receiving conductor, which comprises a plurality of windings arranged adjacently in the first direction. Similarly, at least one receiving conductor of the second receiving pattern path may comprise a plurality of windings arranged adjacently in the first direction or may have only one winding. In particular, the receiving conductor of the first receiving pattern path may have more turns than the receiving conductor of the second receiving pattern path.

[0010] Advantageously, n times the first period length P1.1 or m times the second period length P1.2 is equal to the length L. n·P1.1=L m·P1.2=L,

[0011] The first receiving pattern path is advantageously comprised of at least two receiving conductors, which together generate two phase-shifted first signals, each having a first period length P1.1. These at least two receiving conductors then extend along the first direction in a first periodic pattern, each having a first period length P1.1.

[0012] In yet another aspect of the present invention, the second receiving pattern path comprises at least two receiving conductors, each capable of generating a phase-shifted second signal having a second period length P1.2. These at least two receiving conductors extend along the first direction in a second periodic pattern having a second period length P1.2.

[0013] Advantageously, these receiving pattern paths are arranged to overlap in a second direction perpendicular to the first direction. In particular, these receiving pattern paths can be placed in the overlapping layers of the scanning unit, which is made as a circuit board.

[0014] The first periodic pattern of the receiving conductor of the first receiving pattern path has a first period length P1.1, and the second periodic pattern of the receiving conductor of the second receiving pattern path has a second period length P1.2. As a result, the first signal and the first periodic pattern have the same first period length P1.1 in this case. Similarly, the second signal and the second periodic pattern have the same second period length P1.2.

[0015] Typically, the scanning unit and the scale unit are positioned opposite each other and separated by a gap that extends in a second direction. In yet another aspect of the present invention, the first period length P1.1 is shorter than the second period length P1.2. P1.1 <P1.2

[0016] The second receiving pattern path is positioned at a greater distance from the scale section than the first receiving pattern path in the second direction, which is perpendicular to the first direction.

[0017] At least one receiving conductor of the second receiving pattern path may extend for at least three times the second period length P1.2. Thus, the following holds: L≧3·P1.2

[0018] Advantageously, the scale part has a rotationally symmetric shape around an axis parallel to the first direction. Advantageously, the scale track comprises ribs and gaps alternately arranged along the first direction. Alternatively, the scale track may be formed from a scale structure comprising conductive regions and non-conductive regions alternately arranged along the first direction. The scale structure may have other ferromagnetic geometries.

[0019] When the scale part comprises a plurality of gaps with different depths, this can be achieved, on the one hand, in that the scale part always has a constant outer diameter when viewed in the first direction and, correspondingly, the gaps are formed with different depths. Alternatively or additionally, the depth can also be varied by ribs of different heights, in which case the outer diameter of the scale part is not constant along the first direction.

[0020] Advantageously, the minimum gap of the scale part does not fall below a width of 0.5 mm, and in particular does not fall below 0.2 mm.

[0021] The scale part advantageously has a dimension M in the first direction that is at least larger than the length L plus twice the first period length P1.1: M≧L + 2·P1.1

[0022] According to an advantageous aspect of the invention, in particular the following holds: M≧L + 4·P1.1, In particular, the following may also hold: M≧2·L

[0023] In yet another aspect of the invention, the scale part is formed such that, at least in the region of the scale part, the sum of the width of a certain rib and the width of the gap adjacent to that rib is not equal to the sum of the width of another certain rib and the gap adjacent to that rib.

[0024] Advantageously, the first period length P1.1 is longer than the maximum width of one rib or longer than the width of the largest rib. This view is valid when the rib width varies along the first direction. Alternatively or additionally, the first period length P1.1 is also longer than the maximum width of the gap.

[0025] In yet another aspect of the present invention, each rib has the same width, while the gaps between them have different widths.

[0026] The advantageous features of the present invention can be found in the dependent claims.

[0027] Further details and advantages of the induction-type position measuring device according to the present invention will become apparent from the following description of two embodiments based on the attached drawings. [Brief explanation of the drawing]

[0028] [Figure 1] This is a side view of a position measuring device that determines relative position. [Figure 2] This is a front view of the position measuring device. [Figure 3] This is a plan view of the excitation wires of the scanning unit and the first receiving pattern path. [Figure 4] This is a plan view showing only the excitation wire and the two receiving wires of the first receiving pattern path of the scanning unit. [Figure 5] This is a plan view of the excitation wires of the scanning unit and the second receiving pattern path. [Figure 6] This is a plan view showing only the excitation wire and one receiving wire in the second receiving pattern path of the scanning unit. [Figure 7] This diagram shows the changes in the signals in the first and second receiving wires. [Figure 8] This is a side view of a position measuring device for determining relative position according to a second embodiment. [Figure 9] This is a cross-sectional view of a position measuring device according to a second embodiment. [Modes for carrying out the invention]

[0029] The present invention will be described based on a position measuring device intended to detect the relative position between a scanning unit 1 and a scale unit 2 or scale that is displaceable along a first direction X.

[0030] The scale section 2 is positioned relative to the scanning section 1 such that it faces the scanning section 1 with a gap that extends in the second direction Y.

[0031] The scale section 2 is constructed as a rotationally symmetric body about axis A. This rotationally symmetric body can be manufactured as a single unit from a metal material such as brass, as in the presented embodiment. The scale section 2 comprises a scale track 2.1. The scale track 2.1 extends along a first direction X (measurement direction) and comprises a plurality of ribs 2.11 and a plurality of gaps 2.12 located between them. Thus, the scale track 2.1 consists of a series of alternately arranged ribs 2.11 and gaps 2.12. In the presented embodiment, each rib 2.11 has a width BS of 3.65 mm. In contrast, the gaps 2.12 have different widths BL along the first direction X, where the width BL is approximately 2.66 mm at its maximum and approximately 0.33 mm at its minimum. In the presented embodiment, the scale section 2 is manufactured by a turning process, and the ribs 2.11 have sharp edges defined in the axial direction of the ribs 2.11. Alternatively, the scale section 2 may be constructed such that there is a relatively rounded transition between the rib 2.11 and the gap 2.12.

[0032] The scanning unit 1 has a circuit board 1.1 with several layers and electronic components 1.4 mounted on the circuit board 1.1. Furthermore, a plug portion 1.5 is located on the scanning unit 1, and a cable can be connected to this plug portion, so that the scanning unit 1 can be connected to subsequent electronic devices in this manner. The scanning unit 1 is used to scan the scale portion 2.

[0033] To determine the relative position, the scanning unit 1 includes a first receiving pattern path 1.1 and a second receiving pattern path 1.2, and both receiving pattern paths 1.1 and 1.2 are arranged on different planes or layers.

[0034] Figure 3 shows the first receiving pattern path 1.1 in an enlarged detail. This receiving pattern path includes a first receiving conductor 1.11, a second receiving conductor 1.12, a third receiving conductor 1.13, and a fourth receiving conductor 1.14. The first receiving pattern path 1.1 is surrounded by an excitation conductor 1.3.

[0035] Figure 4 shows only the first receiving conductor 1.11 and the second receiving conductor 1.12 of the first receiving pattern path 1.1 for easier explanation. The receiving conductors 1.11 and 1.12 shown in Figure 4 supply signals that are 90° out of phase.

[0036] In the present embodiment, the first receiving pattern path 1.1 has four receiving conductors 1.11, 1.12, 1.13, and 1.14 arranged offset in the first direction X, so that these receiving conductors can supply four signals with phase differences corresponding to their offset. The receiving conductors 1.11, 1.12, 1.13, and 1.14 are here made as conductor patterns and connected to vias, extending to different layers of the circuit board or scanning unit 1 so that unwanted short circuits at intersections are avoided. Strictly speaking, each of the receiving conductors 1.11, 1.12, 1.13, and 1.14 consists of numerous conductor pieces arranged adjacent to each other in two planes or two layers, but in the following, such structures will be collectively referred to as receiving conductors 1.11, 1.12, 1.13, and 1.14.

[0037] The receiving conductors 1.11, 1.12, 1.13, and 1.14 have a roughly sinusoidal or spatially periodic curve formed in a sinusoidal shape, and all receiving conductors 1.11, 1.12, 1.13, and 1.14 of the first receiving pattern path 1.1 have a first period length P1.1 (Figure 3). Each of the receiving conductors 1.11, 1.12, 1.13, and 1.14 of the first receiving pattern path 1.1 extends over a length L, and its length is a multiple of the first period length P1.1:

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[0038] In the presented embodiment, the length L is set to be 8 times the first period length P1.1 (n=8). In this example, the first period length P1.1 is 5.145 mm, so the length L is 41.16 mm.

[0039] In the presented embodiment, adjacent receiving conductors 1.11, 1.12, 1.13, and 1.14 within the first receiving pattern path 1.1 are positioned offset from each other along the first direction X by 1 / 8 of the entire period of the sine wave, i.e., 1 / 8 of the first period length P1.1, as shown in Figure 3. The receiving conductors 1.11, 1.12, 1.13, and 1.14 are electrically connected to supply 0° and 90° signals on one side and 45° and 135° signals on the other. A first position signal can be determined from the 0° and 90° signals, and a second position signal redundant with respect to the first position signal can be determined from the 45° and 135° signals. Essentially, the first receiving conductors 1.11, 1.12, 1.13, and 1.14 can generate a relatively high-resolution incremental signal when the scale unit 2 moves relative to the scanning unit 1. Figure 7 shows, for example, how the first signal S1.1 generated by the receiving conductors 1.11, 1.12, 1.13, and 1.14 of the first receiving pattern path 1.1 changes when the scale section 2 is displaced by a movement path of length L.

[0040] Figures 5 and 6 show a second receiving pattern path 1.2. This receiving pattern path lies on two layers of the scanning unit 1 or circuit board such that the second receiving pattern path 1.2 is shifted in the second direction Y relative to the first receiving pattern path 1.1. Furthermore, the first receiving pattern path 1.1 is positioned to overlap with the second receiving pattern path 1.2 with respect to it. In the presented embodiment, the second receiving pattern path 1.2 is located further away from the scale unit 2 or axis A than the first receiving pattern path 1.1.

[0041] In the embodiment shown in Figure 5, the second receiving pattern path 1.2 has a fifth receiving conductor 1.21 and a sixth receiving conductor 1.22, i.e., two receiving conductors 1.21 and 1.22, which are offset from each other in the first direction X. This allows these receiving conductors to supply two signals with a phase difference of 90°, corresponding to their offset. The receiving conductors 1.21 and 1.22 are formed as conductor patterns and, here again, are connected vias and extend to different layers of the circuit board or scanning unit 1. Both the fifth receiving conductor 1.21 and the sixth receiving conductor 1.22 are tripled here and connected in series. Here, the fifth receiving conductor 1.21 (0° receiving conductor) and the sixth receiving conductor 1.22 (90° receiving conductor) are electrically tripled by +30° and -30°, respectively. Therefore, the fifth receiving wire 1.21 allows the position of the scale section 2 to be detected at -30°, 0°, and +30° (relative to the phase position of the received signal). Correspondingly, the sixth receiving wire 1.22 allows the position of the scale section 2 to be detected at 60°, 90°, and 120° (relative to the phase position of the received signal).

[0042] As can be seen in Figure 6, the conductor pattern portion of the fifth receiving conductor 1.21 is connected in series with the second receiving pattern path 1.2 at its left end. In contrast, the corresponding circuit connection for the sixth receiving conductor 1.22 is made at the right end of the second receiving pattern path 1.2 (Figure 5). This series circuit connection results in the generation of a 0° signal and a 90° signal, respectively, with amplified amplitudes. The amplification of the signal amplitude is particularly advantageous for the second receiving pattern path 1.2 because, in the second direction Y, this receiving pattern path is further from the scale section 2 than the first receiving pattern path 1.1. Figure 7 illustrates the change in the second signal S1.2 generated by the receiving conductors 1.21 and 1.22 of the second receiving pattern path 1.2 when the scale section 2 is displaced by a path of length L.

[0043] The fifth and sixth receiving conductors 1.21 and 1.22 also have spatially periodic curves, which are formed in a substantially sinusoidal or sinusoidal shape, and each receiving conductor 1.21 and 1.22 of the second receiving pattern path 1.2 has a second period length P1.2 (Figure 6). In the presented embodiment, the second period length P1.2 is 13.72 mm. In the presented embodiment, since the second period length P1.2 is longer than the first period length P1.1, the first period length P1.1 is not equal to the second period length P1.2. The fifth and sixth receiving conductors 1.21 and 1.22 each extend over a length L that is a multiple of the second period length P1.2:

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[0044] In the presented embodiment, the length L is set to three times the second period length P1.2 (m=3), and thus the length L = 41.16 mm = 13.72 mm·3 holds true.

[0045] In the assembled state shown in Figure 1, the scanning unit 1 and the scale unit 2 are facing each other with an air gap between them. This allows for the generation of signals corresponding to the relative position in the receiving conductors 1.11, 1.12, 1.13, 1.14, 1.21, and 1.22 due to the inductive effect when there is relative motion between the scale unit 2 and the scanning unit 1. The prerequisite for forming these corresponding signals is that the excitation conductor 1.3 generates a time-alternating electromagnetic excitation field in the region of the scale structure 2.1 that is scanned one by one. In the illustrated embodiment, the excitation conductor 1.3 is formed as a plurality of flat and parallel individual conductor patterns through which current flows. The scanning unit 1 includes an electronic circuit having an electronic component 1.4. This electronic circuit may, for example, include an ASIC module. The electronic circuit of the scanning unit 1 functions not only as an analysis element but also as an excitation control element, and under its control, an excitation current is generated, which then flows through the excitation conductor 1.3.

[0046] When current flows through excitation wire 1.3, an electromagnetic field is created around excitation wire 1.3 that is oriented in a tubular or cylindrical manner. The resulting magnetic field lines extend around excitation wire 1.3, and the direction of the magnetic field lines depends, in known manner and manner, on the direction of the current within excitation wire 1.3. Eddy currents are induced in the region of rib 2.11, resulting in relative position-dependent field modulation. Correspondingly, the relative positions can be measured by receiving wires 1.11, 1.12, 1.13, 1.14, 1.21, and 1.22, respectively.

[0047] The first receiving pattern path 1.1 is equipped with receiving conductors 1.11, 1.12, 1.13, and 1.14 that extend with a shorter first period length P1.1, and by scanning the scale section 2, the relative position can be determined with relatively detail by the first receiving pattern path 1.1. The second receiving pattern path 1.2, located above it, is equipped with receiving conductors 1.21 and 1.22 that extend with a coarser second period length P1.2, and scans the scale section 2 simultaneously. Therefore, the second receiving pattern path 1.2 enables the determination of the relative position with relatively rough precision. In other respects, all receiving conductors 1.11, 1.12, 1.13, and 1.14 of the first receiving pattern path 1.1 each have the same first period length P1.1, and the receiving conductors 1.21 and 1.22 of the second receiving pattern path 1.2 each have the same second period length P1.2. The scanning of both receiving pattern paths 1.1 and 1.2 is performed simultaneously, and there is no need to switch between the individual receiving pattern paths 1.1 and 1.2. The signals S1.1 received by the receiving conductors 1.11, 1.12, 1.13, and 1.14 of the first receiving pattern path 1.1, and the signals S1.2 received by the receiving conductors 1.21 and 1.22 of the second receiving pattern path 1.2 are shown in Figure 7. From this, it can be seen that when the scale unit 2 moves relative to the first direction X over a movement path of length L, that is, over 41.16 mm in this case, the receiving conductors 1.11, 1.12, 1.13, and 1.14 of the first receiving pattern path 1.1 generate a signal S1.1 with 8 (n=8) complete signal periods, while the receiving conductors 1.21 and 1.22 of the second receiving pattern path 1.2 generate a signal S1.2 with only 3 (m=3) signal periods. The received signals S1.1 and S1.2 are combined using a humming or caliper (vernier) algorithm so that the relative position between the scanning unit 1 and the scale unit 2 can be absolutely determined by both signals S1.1 and S1.2. What is important here is that the first period length P1.1 multiplied by n and the second period length P1.2 multiplied by m of the generated electrical signals S1.1 and S1.2 are of the same magnitude, and m and n are relatively prime.

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[0048] In the present embodiment, the first periodic pattern of the receiving conductors 1.11, 1.12, 1.13, and 1.14 of the first receiving pattern path 1.1 has a first period length P1.1, and the second periodic pattern of the receiving conductors 1.21 and 1.22 of the second receiving pattern path 1.2 has a second period length P1.2. Furthermore, the signal S1.1 generated by the receiving conductors 1.11, 1.12, 1.13, and 1.14 of the first receiving pattern path 1.1 has a first period length P1.1, and the signal S1.2 generated by the receiving conductors 1.21 and 1.22 of the second receiving pattern path 1.2 has a second period length P1.2.

[0049] A second embodiment can be described with reference to Figures 8 and 9. The second embodiment differs from the first embodiment in that a modified scale section 2' is used. This embodiment includes a scale track 2.1' which extends along a first direction X with a plurality of ribs 2.11' and a plurality of gaps 2.12' located between them. In the second embodiment, the gaps 2.12' have different depths HL (Figure 9) along the first direction X, i.e., they have different distances to the scanning section 1 within the scanning area. In contrast, each rib 2.11' has the same distance to the scanning section 1 within the scanning area. By arranging gaps 2.12' of different depths, positional information in the scale section 2' is reflected.

[0050] By designing the scale sections 2 and 2' to be rotationally symmetric, it is possible to accurately determine the relative position even if the scale sections 2 and 2' rotate around axis A during measurement due to assembly conditions or drift motion.

Claims

1. An induction-type position measuring device comprising a scanning unit (1) and a scale unit (2; 2'), the scale unit (2; 2') being disposed so as to be displaceable in a first direction (X) relative to the scanning unit (1), said scanning unit (1) It comprises at least one excitation conductor (1.3), A first receiving pattern path (1.1) having at least one receiving conductor (1.11, 1.12, 1.13, 1.14) extending along the first direction (X) in a first periodic pattern and over at least a certain length (L); a second receiving pattern path (1.2) having at least one receiving conductor (1.21, 1.22) extending in a second periodic pattern along the first direction (X) and over at least the same length (L); the graduation part (2; 2') has a graduation track (2.1; 2.1') ​​with a graduation structure along the first direction (X), the graduation structure being formed by a plurality of ribs (2.11; 2.11') and a plurality of gaps (2.12, 2.12'); the ribs (2.11, 2.11') have different widths (BS) in the first direction (X), or the gaps (2.12; 2.12') have different depths (HL) or different widths (BL) in the first direction (X), the electromagnetic field generated by at least one of the excitation conductors (1.3) can be modulated via the graduation track (2.1, 2.1'), a first signal (S1.1) having a first period length (P1.1) can be generated by the receiving conductors (1.11, 1.12, 1.13, 1.14) of the first receiving pattern path (1.1); a second signal (S1.2) having a second period length (P1.2) can be generated by the receiving conductors (1.21, 1.22) of the second receiving pattern path (1.2); n times the first periodic length (P1.1) is equal to m times the second periodic length (P1.2), m and n are coprime, and n times the first periodic length (P1.1) or m times the second periodic length (P1.2) is equal to or less than the length (L). A position measuring device configured as follows.

2. 2. The inductive position measuring device according to claim 1, wherein the first receiving pattern path (1.1) comprises at least two receiving conductors (1.11, 1.12, 1.13, 1.14), each capable of generating the first signal (S1.1) having the first period length (P1.1).

3. 2. The inductive position measuring device according to claim 1, wherein the second receiving pattern path (1.2) comprises at least two receiving conductors (1.21, 1.22), each capable of generating the second signal (S1.2) having the second period length (P1.2).

4. 4. An induction type position measuring device according to claim 1, wherein the receiving pattern paths (1.1, 1.2) are arranged so as to overlap in a second direction (Y) perpendicular to the first direction (X).

5. 4. An induction-type position measuring device according to claim 1, wherein the first periodic pattern has the first period length (P1.1), and the second periodic pattern has the second period length (P1.2).

6. 6. An inductive position measuring device according to claim 5, wherein at least one of the receiving conductors (1.21, 1.22) of the second receiving pattern path (1.2) extends over at least three times the second period length (P1.2).

7. 4. An induction-type position measuring device according to claim 1, wherein the first period length (P1.1) is shorter than the second period length (P1.2), and the second receiving pattern path (1.2) is arranged at a greater distance from the graduation portion (2, 2') than the first receiving pattern path (1.1) in a second direction (Y) perpendicular to the first direction (X).

8. 4. An induction-type position measuring device according to claim 1, wherein the scale portion (2; 2') has a shape that is rotationally symmetrical about an axis (A) that is oriented parallel to the first direction (X).

9. 4. An induction-type position measuring device according to claim 1, wherein the graduation portion (2; 2') has a dimension (M, M') in the first direction (X) that is at least greater than the length (L) plus twice the first period length (P1.1).

10. 4. An inductive position measuring device according to claim 1, wherein the sum of the width (BS) of a rib (2.11) and the width (BL) of the gap (2.12) adjacent to it is not equal to the sum of the width (BS) of another rib (2.11) and the width (BL) of the gap (2.12) adjacent to it.

11. 4. An inductive position measuring device according to claim 1, wherein the first periodic length (P1.1) is greater than the maximum width (BS) of the rib (2.11) or greater than the maximum width (BL) of the gap (2.12).

12. 4. An inductive position measuring device according to claim 1, wherein all ribs (2.11) have the same width (BS).

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