Electromagnetic inductive encoder

Abstract

Provided is an electromagnetic induction encoder that can suppress the influence of a change in magnetic flux received by a receiver portion and maintain the accuracy of measurement results. An electromagnetic induction encoder 1 includes a scale 2 and a head 3 that is disposed to face the scale 2 and move relative to the scale 2. The head 3 includes a transmitter portion 4 having a plurality of transmitter coils 500 and a receiver portion 5. The receiver portion 5 includes a first receiver portion 51 having at least one receiving coil 500, a second receiver portion 52 disposed separately from the first receiver portion 51 and having at least one receiving coil 500 different from that of the first receiver portion 51, and a connection wiring 53 connecting the first receiver portion 51 and the second receiver portion 52. The first receiver portion 51 and the second receiver portion 52 are arranged in line symmetry with respect to an axis L1 of a Y direction orthogonal to an X direction (measurement direction) in a plane 30 in which the receiving coils 500 are arranged, and are arranged in the same number.

Description

Technical Field

[0001] This invention relates to an electromagnetic induction encoder. Background Technology

[0002] A conventional electromagnetic induction encoder 1 is known to have a scale, which has a scale coil and a head that moves relative to the scale along the measurement direction. For example, in the electromagnetic induction displacement detection device (electromagnetic induction encoder) described in Japanese Patent 2018-159658, the head has a transmitter portion and a receiver portion. The transmitter portion has a transmitting coil that generates magnetic flux in the scale coil, and the receiver portion has a first receiver portion and a second receiver portion that receive changes in magnetic flux from the scale coil. The first and second receiver portions move along the measurement direction. The first and second receiver portions have multiple coil lines, and the multiple receiver coils are arranged along a row direction parallel to the measurement direction. These coil lines are arranged side by side along a column direction orthogonal to the row direction. The receiver portion has one end, another end, and a central portion. The one end and the other end are located at one end and the other end of the receiver portion in the measurement direction, respectively, and have a sparse density of multiple receiver coils. The central portion is located between the one end and the other end and has a dense density of multiple receiver coils.

[0003] Here, the head is positioned at an angle to the scale in the roll, pitch, and yaw directions, which may affect the change in magnetic flux received by the receiver section. For example, the head can rotate relative to the scale, with one end close to the scale and the other end separate from it. In this case, one end of the receiver section is more affected by the change in received magnetic flux, while the other end is less affected.

[0004] In contrast to the effect of magnetic flux variation, in electromagnetic induction displacement detection devices with a sparser density of multiple receiving coils, one end of the multiple receiving coils is less susceptible to changes in magnetic flux received by the receiving unit, even when the head rotates and moves closer to or away from the scale. This is because the magnetic flux variation caused by the multiple receiving coils is smaller than the magnetic flux variation at the center when the multiple receiving coils are denser. The magnitude of the magnetic flux generated in the central portion when the multiple receiving coils are denser is greater than the magnitude of the magnetic flux at one or two ends when the multiple receiving coils are sparser, even when the head rotates and moves closer to or away from the scale. This allows electromagnetic induction displacement detection devices to stabilize changes in magnetic flux received by the receiving portion and suppress the effects of magnetic flux variation. Summary of the Invention

[0005] The problem to be solved by the present invention

[0006] However, although the receiver section described in JP 2018-159658 is arranged symmetrically with respect to a given axial direction or rotation axis of the entire receiver section, the first receiver, second receiver, etc., are not symmetrical. Therefore, changes in magnetic flux received by multiple receiving coils may be received non-uniformly, especially when the head rotates and moves closer to or further away from the scale. The problem is that if the magnetic flux change is non-uniform, the accuracy of the measurement results detected from the magnetic flux change may deteriorate.

[0007] The purpose of this invention is to provide an electromagnetic induction encoder that can suppress the influence of changes in magnetic flux received by the receiver section and maintain the accuracy of the measurement results.

[0008] Problem Solving Methods

[0009] The electromagnetic induction encoder of the present invention includes a scale with a scale coil and a head that moves relative to the scale along a measurement direction. The head has a transmitter portion and a receiver portion. The transmitter portion has a transmitting coil that generates magnetic flux in the scale coil, and the receiver portion has a plurality of receiving coils arranged in the same plane along the measurement direction, which receive changes in magnetic flux from the scale coil. The receiver portion includes: a first receiver portion having at least one receiving coil; a second receiver portion disposed separately from the first receiver portion and having at least one receiving coil different from the first receiver portion; and connecting wiring connecting the first receiver portion and the second receiver portion. The first receiver portion and the second receiver portion are arranged symmetrically in the plane in which the receiving coils are arranged with respect to an axis line of an orthogonal direction orthogonal to the measurement direction. The first receiver portion and the second receiver portion are arranged in the same number.

[0010] According to the present invention, in the receiver section, a first receiver section and a second receiver section, which are separately disposed from the first receiver section, are connected by a connecting wire. The first receiver section and the second receiver section are arranged symmetrically with respect to an axis line in the orthogonal direction, and are arranged in the same number. With this configuration, even if, for example, the head rotates and one end of the head in the measurement direction approaches or moves away from the scale, the receiver section can still stably detect changes in magnetic flux because the receiver section is arranged symmetrically with respect to an axis line in the orthogonal direction, centered on the connecting wire. Therefore, the electromagnetic induction encoder can maintain the accuracy of the measurement results by suppressing the influence of changes in magnetic flux received by the receiver section.

[0011] Here, the electromagnetic induction type displacement detection device described in Japanese Patent 2018-159658 achieves symmetry of the entire receiver section by stacking multiple receiver sections, which results in high manufacturing costs.

[0012] On the other hand, according to the present invention, the first receiver portion and the second receiver portion are arranged symmetrically in the plane in which the receiving coils are arranged with respect to an axis line orthogonal to the measurement direction, and are arranged in the same number. Therefore, symmetry can be achieved without stacking multiple receiver portions. Therefore, the manufacturing cost of the electromagnetic induction encoder can be reduced compared to the manufacturing cost of a conventional encoder.

[0013] The connecting wiring is preferably arranged along a straight line parallel to the measurement direction and is formed to have a length that is an integer multiple of the length of a receiving coil along the measurement direction.

[0014] Here, magnetic flux is generated in the receiving coil by the transmitting coil. When multiple receiving coils are adjacent to each other, each receiving coil will have alternating positive and negative magnetic flux along the adjacent directions of the multiple receiving coils. Furthermore, when the multiple receiving coils are connected to the connecting wiring along the adjacent directions, no magnetic flux is generated in that section of the connecting wiring. Therefore, depending on the length of the connecting wiring, the magnetic flux received by the receiving section may vary, and the accuracy of the measurement results may deteriorate.

[0015] However, with this configuration, the connecting wiring is arranged in a straight line parallel to the measurement direction and is formed to have a length that is an integer multiple of the length of the receiving coil in the measurement direction. Thus, the portion of the connecting wiring that does not generate magnetic flux can be appropriately interpolated. Therefore, the electromagnetic induction encoder can maintain the accuracy of the measurement results by suppressing the influence of changes in magnetic flux received by the receiver section.

[0016] Furthermore, since the connecting wiring is arranged along a straight line parallel to the measurement direction, it is easy to achieve symmetry in the arrangement of multiple receiving coils in the receiving unit about the axis of the orthogonal direction.

[0017] The connecting wiring is preferably configured to have a length that is an odd multiple of the length of a receiving coil along the measurement direction.

[0018] With this configuration, since the connecting wiring is formed to have a length that is an odd multiple of the length of a receiving coil along the measurement direction, it is possible to properly interpolate the portions of the connecting wiring where no magnetic flux is generated, without interfering with the magnetic flux generated in the positive and negative directions in each receiving coil.

[0019] The connecting wiring is preferably configured to have a length that is an even multiple of the length of a receiving coil along the measurement direction.

[0020] With this configuration, since the connecting wiring is formed to have a length that is an even multiple of the length of a receiving coil along the measurement direction, it is possible to properly interpolate the portions of the connecting wiring where no magnetic flux is generated, without interfering with the magnetic flux generated in the positive and negative directions in each receiving coil.

[0021] The receiver section may have multiple wiring layers in which coil wiring forming the receiving coil is disposed. In each of the multiple wiring layers, the coil wiring is preferably arranged symmetrically with respect to an axis line in an orthogonal direction.

[0022] With this configuration, symmetry can be easily achieved in the receiver section because the coil wiring forming the receiving coil is arranged symmetrically with respect to the orthogonal axis lines in each of the multiple wiring layers.

[0023] The transmitting coil is preferably arranged symmetrically with respect to an axis line of an orthogonal direction in the plane in which the transmitting coil is provided, the orthogonal direction being orthogonal to the measurement direction.

[0024] With this configuration, since the transmitting coils are arranged symmetrically in the plane in which they are located along an axis that is orthogonal to the measurement direction, symmetry can be easily achieved not only in the receiver section but also in the transmitter section.

[0025] The transmitting coil may have a pull-out wiring portion having wiring extending from the transmitting coil and pulled out for connection to other components. The pull-out wiring portion is preferably arranged symmetrically in the plane in which the transmitting coil is disposed, with respect to at least one of the axis of the measurement direction and an orthogonal direction orthogonal to the measurement direction.

[0026] With this configuration, even when the transmitting coil has a pull-out wiring section, symmetry can be easily achieved because the pull-out wiring section is arranged symmetrically with respect to the axis of at least one of the measurement direction and the orthogonal direction orthogonal to the measurement direction in the plane in which the transmitting coil is set.

[0027] In this case, the transmitter section may have two transmitting coils. The two transmitting coils are preferably arranged symmetrically in the plane in which the transmitting coils are disposed with respect to the axis of at least one of the measurement direction and an orthogonal direction orthogonal to the measurement direction.

[0028] With this configuration, even when the transmitting section consists of two transmitting coils, symmetry can be easily achieved because the two transmitting coils are arranged symmetrically in the plane in which the transmitting coils are located, with respect to at least one of the axes of the measurement direction and an orthogonal direction orthogonal to the measurement direction.

[0029] The electromagnetic induction encoder of the present invention may include a scale having a scale coil and a head that moves relative to the scale along a measurement direction. The head may have: a transmitter portion having a transmitting coil that generates magnetic flux in the scale coil; and a receiver portion having a plurality of receiving coils arranged in the same plane along the measurement direction, which receive changes in magnetic flux from the scale coil. The transmitting coils may be arranged symmetrically in the plane in which the transmitting coils are disposed with respect to an axis line of an orthogonal direction orthogonal to the measurement direction.

[0030] According to the present invention, since the transmitting coils are arranged symmetrically in the plane in which the transmitting coils are provided about an axis line orthogonal to the measurement direction, symmetry can be easily achieved in the transmitter section. Attached Figure Description

[0031] Figure 1 This is a perspective view showing an electromagnetic induction encoder according to a first embodiment.

[0032] Figure 2 This is a top view of the scale of an electromagnetic induction encoder.

[0033] Figure 3 This is a top view of the head of an electromagnetic induction encoder.

[0034] Figure 4A and Figure 4B This demonstrates the principle of magnetic flux generated in the receiving coil of an electromagnetic induction encoder.

[0035] Figure 5A and 5B This is a schematic diagram showing the wiring layer of the receiver section of an electromagnetic induction encoder.

[0036] Figure 6 This is a top view showing the receiver portion of the electromagnetic induction encoder according to the second embodiment.

[0037] Figure 7 This is a top view showing the transmitter portion of an electromagnetic induction encoder according to a third embodiment. Detailed Implementation

[0038] [First Embodiment]

[0039] In the following text, reference will be made to Figures 1 to 5B The first embodiment of the present invention is described.

[0040] Figure 1 This is a perspective view showing an electromagnetic induction encoder 1 according to a first embodiment.

[0041] like Figure 1As shown, the electromagnetic induction encoder 1 includes an elongated scale 2 and a head 3, the head 3 being positioned to face the scale 2 and move relative to the scale 2 along the measurement direction. The electromagnetic induction encoder 1 is disposed inside an electromagnetic induction caliper, which is used as a measuring instrument.

[0042] The electromagnetic induction caliper moves the scale 2 and head 3 relative to each other along the X direction, which is the measurement direction, and uses the electromagnetic induction encoder 1 to detect the amount of movement between them using induced current. Based on the detected amount of movement, the measurement result is output to a display unit, such as an LCD display screen not shown in the figure.

[0043] In the following description and each figure, the longitudinal direction of the scale 2 and the direction of movement (measurement direction) of the head 3 are described as the X direction, and the width direction of the scale 2, which is orthogonal to the X direction, is described as the Y direction.

[0044] Figure 2 This is a top view of the scale 2 of the electromagnetic induction encoder 1.

[0045] like Figure 2 As shown, the scale 2 has an insulating substrate 21 made of long glass epoxy resin and a scale coil 22 facing the head 3.

[0046] The insulating substrate 21 can be made of a material such as glass or silicon instead of glass epoxy resin.

[0047] The scale coil 22 is made of a low-resistance material such as aluminum, copper or gold, and includes a rectangular wire with a width W in the X direction.

[0048] The scale coil 22 is arranged on the scale 2 at intervals W along the X direction, the intervals W having the same length as the width W of the scale coil 22. The scale coil 22 can be a metal plate or the like instead of a wire, and such metal plates can be arranged periodically.

[0049] Figure 3 This is a top view of the head 3 of the electromagnetic induction encoder 1.

[0050] like Figure 3 As shown, the head 3 has a transmitter portion 4 disposed on an insulating substrate 31 made of glass epoxy resin, and a receiver portion 5 for receiving changes in magnetic flux from the scale coil 22. The insulating substrate 31 can be made of a material such as glass or silicon instead of glass epoxy resin.

[0051] The transmitter unit 4 is configured to face the scale 2 and has a transmitting coil 41 that generates magnetic flux in the scale coil 22 (see [link]). Figure 2 ).

[0052] The transmitting coil 41 is made of a low-resistance material such as aluminum, copper, or gold, and is arranged in a generally rectangular shape around the receiver portion 5. The transmitting coil 41 need not be arranged in a generally rectangular shape around the receiver portion 5, and can be configured in any way as long as it can generate magnetic flux in the scale coil 22.

[0053] The transmitting coil 41 is arranged symmetrically about the axis L1 in the Y direction in the plane 30 where the transmitting coil 41 is provided, the Y direction being orthogonal to the X direction, which is the measurement direction.

[0054] The transmitting coil 41 has a pull-out wiring portion 42, which has wiring extending from the transmitting coil 41 and pulled out to connect to other components.

[0055] The pull-out wiring portion 42 is arranged symmetrically in the plane 30 on which the transmitting coil 41 is provided, with respect to at least one of the axes of the X direction (which is the measurement direction) and the Y direction (which is orthogonal to the X direction). In this embodiment, the pull-out wiring portion 42 is arranged symmetrically with respect to the axis L1 of the Y direction (which is an orthogonal direction). At least one wire in the pull-out wiring portion 42 has a connection portion 43 for connecting to other components. The connection portion 43 is a through hole, via, or the like.

[0056] The receiver section 5 has a plurality of receiving coils 500 arranged inside the transmitting coil 41 and on the same side along the X direction, which is the measurement direction for receiving changes in magnetic flux from the scale coil 22. The receiver section 5 has a first receiver section 51 with at least one receiving coil 500, a second receiver section 52 disposed separately from the first receiver section 51 and having at least one receiving coil 500 different from the first receiver section 51, and a connecting wire 53 connecting the first receiver section 51 and the second receiver section 52. The receiving coils 500 constituting the first receiver section 51 and the second receiver section 52 and the connecting wire 53 are formed of low-resistance materials such as aluminum, copper, and gold.

[0057] The first receiver section 51 and the second receiver section 52 are arranged symmetrically with respect to the axis L1 orthogonal to the X direction (measurement direction) in the plane 30 where the receiving coils 500 are arranged, and are arranged in the same number. In this embodiment, the first receiver section 51 has four receiving coils 500, and the second receiver section 52 has four receiving coils 500, each receiving coil having the same number of receiving coils 500. The first receiver section 51 and the second receiver section 52 are arranged symmetrically with respect to the axis L1 in the Y direction, and the connecting wiring 53 is located at the center. In this embodiment, the number of receiving coils 500 in the first receiver section 51 and the second receiver section 52 is four, but each may have more or fewer receiving coils 500.

[0058] The connecting wire 53 is arranged along a straight line parallel to the X direction, which is the measurement direction, and is formed to have a length that is an integer multiple of the length D1 of the receiving coil 500 in the X direction. Specifically, the connecting wire 53 is formed to have a length that is an odd multiple of the length D1 of the receiving coil 500 in the X direction. In this embodiment, the connecting wire 53 is formed to have a length that is the same as the length D1 of the receiving coil 500 in the X direction. The connecting wire 53 may not be the same as the length D1 in the X direction of the receiving coil 500, but may be formed to be three times or five times the length D1.

[0059] The connecting wiring 53 is arranged such that the line L2 extending from the connecting wiring 53 is positioned at the center of a length D2 in the Y direction, which is the orthogonal direction of each receiving coil 500.

[0060] Figure 4A and Figure 4B The principle of the magnetic flux generated in the receiving coil 500 of the electromagnetic induction encoder 1 is illustrated. Specifically, Figure 4A The magnetic flux generated in the receiving coil 500 without the connection wiring 53 is shown. Figure 4B The magnetic flux generated in the receiving coil 500 having the connecting wire 53 is shown.

[0061] Here, as Figure 4A As shown, positive and negative magnetic flux are alternately generated in the receiving coils 500 arranged side-by-side along the X direction, which is the measurement direction. Therefore, if the connecting wiring 53 is formed with arbitrary length, the balance between the positive and negative magnetic flux may be lost, and the accuracy of the measurement results may deteriorate.

[0062] However, as Figure 4BAs shown, by forming a connecting wire 53 in a receiving coil 500 with a length that is an odd multiple or the same as the length D1 in the X direction, which is the measurement direction, the magnetic flux that should be generated at the connecting wire 53 can be interpolated in the positive direction. In the electromagnetic induction encoder 1, the first receiver section 51 and the second receiver section 52 can be arranged in a linearly symmetrical manner through the connecting wire 53, and the degradation of measurement accuracy can be suppressed.

[0063] Figure 5A and 5B This is a schematic diagram showing the wiring layer of the receiver section 5 of the electromagnetic induction encoder 1. Specifically, Figure 5A The coil wiring 55 without the connected wiring 53 is shown. Figure 5B A coil wire 55 with a connecting wire 53 is shown.

[0064] The receiver section 5 has multiple wiring layers (not shown in the figure), in which coil wiring 55 forming the receiving coil 500 is provided. The coil wiring 55 is provided on the multiple wiring layers and is arranged symmetrically with respect to the axis L1 line in the Y direction, which is an orthogonal direction, in each wiring layer.

[0065] Specifically, at least two coil wirings 55a and 55b are used for coil wiring 55 across multiple wiring layers. For ease of explanation, in Figure 5A and 5B In the diagram, coil wiring 55a is shown in solid line, while another coil wiring 55b, which is different from coil wiring 55a, is shown in dashed line.

[0066] like Figure 5A As shown, when connecting wiring 53 is not used, connecting wirings 55a and 55b are not arranged symmetrically with respect to the axis L1 in the Y direction (orthogonal direction). If they are not arranged symmetrically with respect to the axis L1 in the Y direction, the balance of the detected magnetic flux may be disrupted, and the accuracy of the measurement results may deteriorate.

[0067] However, as Figure 5B As shown, by using the connecting wiring 53, the electromagnetic induction encoder 1 can arrange the coil wirings 55a and 55b symmetrically with respect to the axis L1 in the Y direction (orthogonal direction). In the electromagnetic induction encoder 1, by connecting the wiring 53, the coil wirings 55a and 55b can be arranged in a linearly symmetrical manner, and the degradation of measurement accuracy can be suppressed.

[0068] According to this first embodiment, the following functions and effects can be obtained.

[0069] (1) In the receiver section 5, the first receiver section 51 and the second receiver section 52, which are separately arranged from the first receiver section 51, are connected by a connecting wire 53. The first receiver section 51 and the second receiver section 52 are arranged symmetrically with respect to the axis line in the Y direction, which is an orthogonal direction, and are arranged in the same number. With this configuration, even if, for example, the head 3 rotates and one end of the head 3 in the X direction (measurement direction) approaches or moves away from the scale, the receiver section 5 can still stably detect changes in magnetic flux because the receiver section 5 is arranged symmetrically with respect to the axis line L1 in the Y direction (orthogonal direction) with the connecting wire 53 as the center. Therefore, the electromagnetic induction encoder 1 can maintain the accuracy of the measurement results by suppressing the influence of changes in magnetic flux received by the receiver section 5.

[0070] (2) The first receiver section 51 and the second receiver section 52 are arranged symmetrically with respect to the axis L1, which is orthogonal to the X direction (measurement direction), in the plane 30 on which the receiving coil 500 is arranged, and are arranged in the same number. Thus, symmetry can be achieved. Therefore, the manufacturing cost of the electromagnetic induction encoder 1 can be reduced compared to that of a conventional encoder.

[0071] (3) The connecting wiring 53 is arranged along a straight line parallel to the X direction, which is the measurement direction, and is formed to have a length that is an integer multiple of the length of the receiving coil 500 in the measurement direction. Thus, magnetic flux can be appropriately interpolated at the connecting wiring 53. Therefore, the electromagnetic induction encoder 1 can maintain the accuracy of the measurement results by suppressing the influence of changes in magnetic flux received by the receiver section 5.

[0072] (4) Since the connecting wiring 53 is arranged in a straight line parallel to the X direction (measurement direction), the symmetry of the arrangement of the multiple receiving coils 500 in the receiving unit 5 relative to the axis L1 in the Y direction (orthogonal direction) can be easily achieved.

[0073] (5) Since the connecting wiring 53 is formed to have a length that is an odd multiple of the length in the X direction (measurement direction) of a receiving coil 500, magnetic flux can be properly interpolated at the connecting wiring 53 without interfering with the magnetic flux generated in the positive and negative directions in each receiving coil 500.

[0074] (6) Since the coil wiring 55 forming the receiving coil 500 is arranged symmetrically with respect to the axis L1 line in the Y direction (orthogonal direction) in each of the multiple wiring layers, symmetry can be easily achieved at the receiver section 5.

[0075] (7) Since the transmitting coil 41 is arranged symmetrically in the plane 30 on which the transmitting coil 41 is provided with respect to the axis L1 of the Y direction (orthogonal direction) which is orthogonal to the X direction (measurement direction), symmetry can be easily achieved not only in the receiver section 5 but also in the transmitter section 4.

[0076] (8) Even when the transmitting coil 41 has a pull-out wiring portion 42, since the pull-out wiring portion 42 is arranged symmetrically in the plane 30 on which the transmitting coil 41 is provided with respect to the axis of at least one of the X direction (measurement direction) and the Y direction, wherein the Y direction is an orthogonal direction orthogonal to the measurement direction, symmetry can be easily achieved.

[0077] [Second Embodiment]

[0078] Below, based on Figure 6 A second embodiment of the invention is described below. In the following description, the parts that have been described are indicated by the same reference numerals, and their descriptions are omitted.

[0079] Figure 6 This is a top view showing the receiver portion 5A of the electromagnetic induction encoder 1A according to the second embodiment. Apart from the receiver portion 5A, the head 3 in the second embodiment has a similar structure to the head 3 in the first embodiment described above (see...). Figure 3 ).

[0080] In the first embodiment, the connection wiring 53 of the receiver section 5 is formed to have a length that is an odd multiple of the length D1 of the receiving coil 500 in the X direction (measurement direction).

[0081] The connection wiring 53A of the receiver section 5A in the second embodiment differs from that in the first embodiment described above in that it is formed to have a length that is an even multiple of the length D1 of the receiving coil 500 in the X direction (measurement direction).

[0082] Specifically, such as Figure 6 As shown, the connecting wire 53A is formed to have twice the length, which is an even multiple of the length D1 of a receiving coil 500 in the X direction. The connecting wire 53A can be formed to have four or six times the length, instead of twice the length D1 of a receiving coil 500 in the X direction.

[0083] In this embodiment, although the direction of the magnetic flux generated in each receiving coil 500 is not symmetrical with respect to the axis L1 in the Y direction (orthogonal direction), the entire receiver portion 5A is symmetrical with respect to the axis L1 in the Y direction. Therefore, the connecting wiring 53A is formed to have a length that is an even multiple of the length D1 of a receiving coil 500 in the X direction, which is the measurement direction, so that the magnetic flux to be generated in the connecting wiring 53A can be interpolated according to the appropriate length.

[0084] In this second embodiment, functions and effects similar to those in (1) to (4) and (6) to (8) of the first embodiment can also be obtained. In addition, the following functions and effects can also be obtained.

[0085] (9) Since the connecting wire 53A is formed with twice the length, which is an even multiple of the length in the X direction (measurement direction) of a receiving coil 500, the magnetic flux at the connecting wire 53A can be appropriately interpolated without interfering with the magnetic flux generated in the positive and negative directions in each receiving coil 500.

[0086] [Third Embodiment]

[0087] Below, based on Figure 7 A third embodiment of the invention is described below. In the following description, the parts that have been described are indicated by the same reference numerals, and their descriptions are omitted.

[0088] Figure 7 This is a top view showing the transmitter portion 4B of the electromagnetic induction encoder 1B according to the third embodiment. Besides the transmitter portion 4B, the head 3 in the third embodiment (see...) Figure 3 It has a configuration similar to head 3 in the first embodiment described above.

[0089] In the first embodiment above, the transmitter section 4 consists of a single transmitting coil 41 and is arranged in a rectangular shape around the receiver section 5.

[0090] The third embodiment differs from the first embodiment in that the transmitter portion 4B has two transmitting coils 41B, and the two transmitting coils 41B are arranged symmetrically on the plane 30 where the transmitting coils 41B are provided with respect to the axis of at least one of the X direction, which is the measurement direction, and the Y direction, which is an orthogonal direction orthogonal to the X direction.

[0091] Specifically, such as Figure 7 As shown, the two transmitting coils 41B are arranged side by side along the X direction, which is the measurement direction. It should be noted that the two transmitting coils 41B can also be arranged side by side along the Y direction.

[0092] The pull-out wiring portion 42B is provided at both ends along the X direction, which serves as the measurement direction of the transmitter portion 4B. The pull-out wiring portion 42B is arranged symmetrically in the plane 30 on which the transmitting coil 41B is provided, about the axis L2 of the X direction (measurement direction) and the axis L1 of the Y direction (orthogonal direction to the X direction).

[0093] If transmitter 4B and receiver 5 (see...) Figure 3 If they cannot be placed on the same plane, then the transmitter 4B and receiver 5 can be placed on separate parts. Specifically, the transmitter part 4B and the transmitter part 5 can be placed facing each other, and the scale 2 can be placed between the transmitter part 4B and the receiver part 5. This arrangement allows the receiver part 5 to detect the relative movement of the scale 2 placed between the transmitter part 4B and the receiver part 5.

[0094] In this third embodiment, functions and effects similar to those in (1) to (7) of the first embodiment can also be obtained. In addition, the following functions and effects can also be obtained.

[0095] (10) Even when the transmitter part 4B consists of two transmitting coils 41B, the two transmitting coils 41B are arranged symmetrically in the plane 30 on which the transmitting coils 41B are provided about the axis L2 of the X direction (measurement direction) and the axis L1 of the Y direction (orthogonal direction to the measurement direction). Therefore, symmetry can be easily achieved.

[0096] [Modification of the Implementation Example]

[0097] Note that the present invention is not limited to each of the above embodiments, but includes modifications and improvements within the spirit and scope of the present invention.

[0098] For example, in each of the above embodiments, electromagnetic induction encoders 1, 1A, and 1B are used as measuring instruments in electromagnetic induction calipers. Electromagnetic induction encoders can also be used in other measuring instruments, such as dial indicators (test indicators) or micrometers. That is, electromagnetic induction encoders are not particularly limited in terms of the type and method of the measuring instrument used, and can be used with other measuring instruments, etc. There are no particular limitations on the devices in which the electromagnetic induction encoders of this invention are installed.

[0099] Electromagnetic induction encoders can be used in devices other than measuring equipment, such as sensors.

[0100] In the above embodiments, electromagnetic induction encoders 1, 1A and 1B are so-called linear encoders with a long scale 2, but they can also be so-called rotary encoders, wherein the scale is formed in an arc shape.

[0101] In the first embodiment, the connecting wire 53 of the receiver section 5 is formed to have a length that is an odd multiple of the length D1 of the receiving coil 500 along the X direction, which is the measurement direction. In the second embodiment, the connecting wire 53A of the receiver section 5A is formed to have a length that is an even multiple of the length D1 of the receiving coil 500 in the X direction. However, the connecting wire can be formed to any length. Although the connecting wires 53 and 53A are arranged on a straight line parallel to the X direction, which is the measurement direction, the connecting wires are not necessarily arranged on this straight line. In short, the connecting wires should be able to connect the first receiver section to the second receiver section.

[0102] Although only one pair of lead-out wiring portions 42 and 42B are provided in the first and third embodiments described above, multiple pairs can be provided in the transmitter portions 4 and 4B. In short, in the plane where the transmitting coil is located, the lead-out wiring portions should be arranged symmetrically about the axis of at least one of the measurement direction and an orthogonal direction orthogonal to the measurement direction.

[0103] In the above embodiments, the transmitter sections 4 and 4B are also arranged in a linearly symmetrical manner, but the transmitter sections do not necessarily have to be arranged in a linearly symmetrical manner.

[0104] Industrial applicability

[0105] As described above, the present invention can be applied to electromagnetic induction encoders.

Claims

1. An electromagnetic induction encoder comprising a scale having a scale coil and a head that moves relative to the scale along a measurement direction, wherein the head includes: The transmitter unit has a transmitting coil that generates magnetic flux in the scale coil; and The receiver section has multiple receiving coils arranged in the same plane along the measurement direction, which receive changes in magnetic flux from the scale coils, and The receiver portion includes: The first receiver section has at least one receiving coil; The second receiver section is disposed separately from the first receiver section and has at least one receiving coil different from that of the first receiver section; and Connect the wiring to the first receiver section and the second receiver section. Furthermore, the first receiver portion and the second receiver portion are arranged symmetrically with respect to the axis of the orthogonal direction in the plane in which the receiving coil is arranged, and are arranged in the same number, wherein the orthogonal direction is orthogonal to the measurement direction; The receiver section has multiple wiring layers, in which coil wiring forming a receiving coil is provided, and the coil wiring is arranged symmetrically with respect to the axis line in the orthogonal direction in each wiring layer.

2. The electromagnetic induction encoder according to claim 1, wherein, The connecting wiring is arranged along a straight line parallel to the measurement direction and is configured to have a length that is an integer multiple of the length of a receiving coil along the measurement direction.

3. The electromagnetic induction encoder according to claim 2, wherein, The connection wiring is configured to have a length that is an odd multiple of the length of a receiving coil along the measurement direction.

4. The electromagnetic induction encoder according to claim 2, wherein, The connection wiring is configured to have a length that is an even multiple of the length of a receiving coil along the measurement direction.

5. The electromagnetic induction encoder according to claim 1, wherein, The transmitting coil is arranged symmetrically in the plane in which it is located relative to an axis line of an orthogonal direction, which is orthogonal to the measurement direction.

6. The electromagnetic induction encoder according to claim 1, wherein, The transmitting coil has a pull-out wiring portion having wiring extending from the transmitting coil and pulled out to connect to other components, and the pull-out wiring portion is arranged symmetrically in the plane on which the transmitting coil is disposed with respect to at least one of the axis of the measurement direction and an orthogonal direction orthogonal to the measurement direction.

7. The electromagnetic induction encoder according to claim 4, wherein, The transmitter unit has two transmitting coils, and the two transmitting coils are arranged symmetrically in the plane in which the transmitting coils are disposed with respect to the axis of at least one of the measurement direction and an orthogonal direction orthogonal to the measurement direction.

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