Position detection device

Abstract

In the present invention, three or more first detection reception coils (51 to 53) are provided along the circumferential direction (Dc) of a substrate (30) and are connected in series, three or more second detection reception coils (61 to 63) are provided along the circumferential direction (Dc) of the substrate (30) and are connected in series, and a signal processing unit (110) receives input of a first detection signal value obtained by adding up first signals respectively generated in the plurality of first detection reception coils (51 to 53) and also receives input of a second detection signal value obtained by adding up second signals respectively generated in the plurality of second detection reception coils (61 to 63), and detects the angle of a rotating member on the basis of the first detection signal value and the second detection signal value.

Description

Position detection device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2023-202120, filed on November 29, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a position detection device.

[0003] Position detection devices that detect the rotation angle of a shaft member have been proposed (see, for example, Patent Document 1). Specifically, in this position detection device, a rotating member is coupled to a shaft member so as not to rotate relative to the shaft member, and the rotating member rotates integrally with the shaft member as the shaft member rotates. In this position detection device, an arc-shaped substrate is disposed facing the rotating member. A first sine-wave receiving coil and a second cosine-wave receiving coil are formed on the substrate. More specifically, in this position detection device, the first receiving coil and the second receiving coil are disposed in opposing regions of the substrate across the shaft member. The position detection device detects the rotation angle of the shaft member based on first detection signal values ​​from the first receiving coils and second detection signal values ​​from the second receiving coils.

[0004] European Patent No. 3792599

[0005] Currently, there is a demand for increasing the first detection signal value and the second detection signal value to increase the signal-to-noise ratio (S / N ratio) and thereby improve detection accuracy.

[0006] An object of the present disclosure is to provide a position detection device that can improve detection accuracy.

[0007] According to one aspect of the present disclosure, a position detection device comprises: a rotating member that rotates around the rotation axis of the shaft member; a substrate that is shaped to have an arc portion circumferentially along the rotation axis and is arranged opposite the rotating member; a first detection receiving coil formed on the substrate and that generates a first signal having periodicity corresponding to changes in the magnetic field associated with the rotation of the rotating member; a second detection receiving coil formed on the substrate and that generates a second signal having a phase different from that of the first signal and that has periodicity corresponding to changes in the magnetic field associated with the rotation of the rotating member; and a signal processing unit that detects a rotation angle of the rotating member, wherein three or more of the first detection receiving coils are provided along the circumferential direction of the substrate and connected in series, and three or more of the second detection receiving coils are provided along the circumferential direction of the substrate and connected in series, and the signal processing unit receives as input a first detection signal value obtained by adding together the respective first signals generated in the plurality of first detection receiving coils and a second detection signal value obtained by adding together the respective second signals generated in the plurality of second detection receiving coils, and detects the angle of the rotating member based on the first detection signal value and the second detection signal value.

[0008] According to this, a plurality of first detection receiving coils that generate first signals are connected in series, and a plurality of second detection receiving coils that generate second signals are connected in series. Therefore, a first detection signal value obtained by adding together a plurality of first signals is input to the signal processing unit, and a second detection signal value obtained by adding together a plurality of second signals is input to the signal processing unit. Therefore, the influence of noise can be reduced, thereby increasing the S / N ratio and improving detection accuracy.

[0009] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below.

[0010] 1 is a plan view of the position detection device in the first embodiment as viewed from the axial direction. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a plan view showing the transmitter coil and receiver coil on the substrate. FIG. 4 is a plan view showing a state in which a circuit board is arranged on the substrate. FIG. 5 is a schematic view of the transmitter coil and receiver coil formed on the substrate. FIG. 6 is a block diagram of the circuit board. FIG. 7 is a view showing a first voltage value generated in the first detection receiver coil. FIG. 8 is a view showing a second voltage value generated in the second detection receiver coil. FIG. 9 is a view showing the relationship between amplitudes of detected voltage values ​​between the position detection device of the comparative example and the position detection device of this embodiment. FIG. 10 is a view showing a state when the substrate is displaced in the X-axis direction. FIG. 11 is a view showing a state when the substrate is displaced in the Y-axis direction. FIG. 12 is a view showing angular accuracy when the substrate is displaced in the X-axis direction in the position detection device of the first embodiment. FIG. 13 is a view showing angular accuracy when the substrate is displaced in the X-axis direction in the position detection device of the comparative example. FIG. 14 is a view showing the relationship between separation angle and angular error. FIG. 15 is a view for explaining the formation angle of the receiver coil, the formation angle of the transmitter coil, and the separation angle. FIG. 16 is a plan view of a substrate component plate that constitutes the substrate. FIG. 17 is a plan view of the position detection device in the second embodiment as viewed from the axial direction. FIG. 18 is a view showing the transmitter coil and receiver coil on the substrate of the second embodiment. Fig. 10 is a plan view of a position detection device according to a modified example of the second embodiment, as viewed from the axial direction. Fig. 11 is a diagram schematically showing a transmitter coil and a receiver coil formed on a substrate according to a third embodiment. Fig. 12 is a plan view showing a state in which a circuit board is arranged on a substrate according to a fourth embodiment. Fig. 13 is a diagram schematically showing a transmitter coil and a receiver coil formed on a substrate according to a fifth embodiment.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals.

[0012] First Embodiment A first embodiment will be described with reference to the drawings. The position detection device 10 of this embodiment is suitable for use in detecting the rotation angle of a motor such as a main motor or an in-wheel motor.

[0013] As shown in FIGS. 1 and 2, the position detection device 10 of this embodiment includes a rotating member 20 and a substrate 30 supported by a shaft member 70. The rotational axis CL shown in FIGS. 1 to 3 is the center of rotation of the shaft member 70 and the rotating member 20. For example, when detecting the rotation angle of a motor mounted on a vehicle, it corresponds to the rotational axis of the motor. Hereinafter, the direction in which the rotational axis CL extends is referred to as the axial direction Da, the direction extending radially from the axis of the rotational axis CL is referred to as the radial direction Dr, and the rotational direction of the rotational axis CL is referred to as the circumferential direction Dc. The axial direction Da and the radial direction Dr intersect each other, or more precisely, are perpendicular to each other. Although FIG. 1 is a plan view, the shaft member 70 is hatched for ease of understanding.

[0014] The rotating member 20 is made of a conductive material such as metal, is formed in a flat plate shape having a thickness in the axial direction Da, and is coupled to the shaft member 70 so as to be non-rotatable relative to the shaft member 70. For example, the rotating member 20 may be made non-rotatable relative to the shaft member 70 by using a rotation prevention key member, or may be made non-rotatable relative to the shaft member 70 by being welded to the shaft member 70.

[0015] The rotating member 20 is a rotating body supported by the shaft member 70 so as to be rotatable around a predetermined rotation axis CL, and rotates integrally with the shaft member 70. Therefore, the rotation angle of the rotating member 20 is detected, and thereby the rotation angle (i.e., the position) of the shaft member 70 is detected.

[0016] The rotating member 20 of this embodiment has a connecting portion 21 and five targets 22 to 26. The five targets 22 to 26 provided on the rotating member 20 rotate integrally with the rotation of the shaft member 70, with the rotation axis CL serving as the rotation center.

[0017] The rotating member 20 of this embodiment is configured as a single component including the connecting portion 21 and the five targets 22 to 26. The rotating member 20 is formed in a flat plate shape with a uniform thickness in the axial direction Da. Therefore, the thicknesses of the five targets 22 to 26 in the axial direction Da are the same.

[0018] The connecting portion 21 is a portion located in the center of the rotating member 20, and has an insertion hole 21a formed in the center that penetrates in the axial direction Da, giving it an annular shape centered on the rotation axis CL. The shaft member 70 is inserted into the insertion hole 21a so as to be unable to rotate relative to the connecting portion 21. In other words, the rotating member 20 is connected to the shaft member 70 at this connecting portion 21.

[0019] The five targets 22 to 26 are each formed to protrude outward in the radial direction Dr from the connecting portion 21. In other words, the rotating member 20 is configured to have five recesses formed from the outer edge side, thereby including the five targets 22 to 26. The five targets 22 to 26 are arranged at equal intervals in the circumferential direction Dc. Specifically, the targets 22 to 26 are arranged at 72° intervals in the circumferential direction Dc. The lengths of the five targets 22 to 25 in the circumferential direction Dc (i.e., the intervals between the five targets 22 to 25 in the circumferential direction Dc) are adjusted to match the lengths of the coils 51 to 53 and 61 to 63 in the circumferential direction Dc, which will be described later.

[0020] 1, the targets 22 to 26 of this embodiment are fan-shaped, with the size in the circumferential direction Dc gradually increasing from the innermost portion in the radial direction Dr to the outermost portion in the radial direction Dr. In this embodiment, all five targets 22 to 26 have the same shape and, as described above, rotate integrally with the rotation of the shaft member 70.

[0021] The substrate 30 includes a printed circuit board or the like, which is a multilayer substrate in which insulating films and wiring layers are alternately stacked. Although not shown in FIG. 1 and other drawings, the substrate 30 of this embodiment includes a circuit board 100 having a signal processing unit 110 that performs angle calculations, as shown in FIG. 4 . The circuit board 100 is positioned so as not to overlap with the coils 40, 51-53, and 61-63 (described later), and is electrically connected to the coils 40, 51-53, and 61-63 (described later). However, the circuit board 100 is positioned within the area surrounded by the transmitter coil 40. Although not specifically shown, the substrate 30 also includes various electronic components such as resistors, diodes, and capacitors, as well as terminals for connecting to an external circuit. The electronic components and terminals may be positioned within the area surrounded by the transmitter coil 40, as with the circuit board 100, or may be positioned outside the area surrounded by the transmitter coil 40.

[0022] Hereinafter, the normal direction to the surface direction of the substrate 30 will be simply referred to as the normal direction. Note that the normal direction of the substrate 30 also coincides with the axial direction Da because the substrate 30 and the rotating member 20 are disposed to face each other in the axial direction Da, as will be described later.

[0023] As shown in FIGS. 1 and 2 , the substrate 30 faces the targets 22 to 26 of the rotating member 20 and is disposed on one side of them in the axial direction Da, spaced a predetermined distance g from them. In this embodiment, the substrate 30 is an arc-shaped plate having a through-hole 30c formed in the center thereof in the axial direction Da and a notch formed in a portion of an imaginary circle centered on the shaft member 70. In other words, the substrate 30 has an arc-shaped portion configured to coincide with the arc of the imaginary circle centered on the shaft member 70. As shown in FIG. 3 , an opening is formed in the substrate 30, giving it a bow-like or C-shaped configuration with two ends 31, 32 in the circumferential direction Dc. The substrate 30 is disposed so that the shaft member 70 is inserted through the through-hole 30c. More specifically, the substrate 30 is disposed so that the center CK of the substrate 30 (i.e., the center of the through-hole 30c) coincides with the rotation axis CL.

[0024] The substrate 30 is disposed so that the distance g between the substrate 30 and each of the targets 22 to 25 in the axial direction Da is the same for all targets. The substrate 30 is disposed on a support member (not shown) so as to be a non-rotating member with respect to the rotating member 20. Therefore, the rotating member 20 rotates relative to the substrate 30.

[0025] The substrate 30 has one planar surface 30a and another planar surface 30b that are perpendicular to the axial direction Da. The one planar surface 30a of the substrate 30 is provided on one side of the substrate 30 in the axial direction Da. The other planar surface 30b of the substrate 30 is provided on the other side of the substrate 30 opposite to the one planar surface 30a in the axial direction Da.

[0026] 1 and 3, the wiring layers of the substrate 30 are appropriately connected between the one surface 30a side and the other surface 30b side, thereby forming the transmitter coil 40, the first first detection receiver coil 51, the first second detection receiver coil 52, the first third detection receiver coil 53, the second first detection receiver coil 61, the second second detection receiver coil 62, and the second third detection receiver coil 63. The transmitter coil 40, the first first detection receiver coil 51, the first second detection receiver coil 52, the first third detection receiver coil 53, the second first detection receiver coil 61, the second second detection receiver coil 62, and the second third detection receiver coil 63 are configured such that the wiring layers of the transmitter coil 40, the first first detection receiver coil 51, the second first detection receiver coil 52, the first third detection receiver coil 53, the second first detection receiver coil 61, the second second detection receiver coil 62, and the second third detection receiver coil 63 are appropriately connected via vias so as not to interfere with each other. In addition, in Figures 1 and 3, for ease of understanding, the transmitting coil 40, the first receiving coil for first detection 51, the second receiving coil for first detection 52, and the third receiving coil for first detection 53 are shown with solid lines, and the first receiving coil for second detection 61, the second receiving coil for second detection 62, and the third receiving coil for second detection 63 are shown with dashed lines.

[0027] Specifically, the transmitter coil 40 is wound multiple times in the normal direction and is formed in the shape of an arc frame with the circumferential direction Dc as the longitudinal direction, and has a configuration in which lead-out wiring 41 connected to the circuit board 100 is formed at the longitudinal end. Furthermore, the transmitter coil 40 of this embodiment is formed so as to collectively surround all of the first detection receiver coil 51, the first detection second receiver coil 52, the first detection third receiver coil 53, the second detection first receiver coil 61, the second detection second receiver coil 62, and the second detection third receiver coil 63. While the transmitter coil 40 is simplified as having one turn in FIGS. 1 and 3 , the actual transmitter coil 40 is wound multiple times as described above. Furthermore, the transmitter coil 40 may be formed in multiple layers to increase the number of turns in order to increase the amplitude of the first voltage value V1 and the second voltage value V2, which will be described later.

[0028] The first detection first receiving coil 51, the first detection second receiving coil 52, and the first detection third receiving coil 53 are each formed to form a closed-loop sinusoidal wave in the normal direction and are arranged in order in the circumferential direction Dc. The first detection first receiving coil 51, the first detection second receiving coil 52, and the first detection third receiving coil 53 are connected in series. The first detection first receiving coil 51 is provided with lead-out wiring 54 for connection to the circuit board 100. The first detection first receiving coils 51 may be formed in multiple wiring layers of the substrate 30 and connected in series to increase the amplitude of the first voltage value V1 (described later). That is, although one period of the first detection first receiving coils 51 is shown in FIG. 3 , multiple first detection first receiving coils 51 may be formed in the thickness direction of the substrate 30 and connected in series. Similarly, the first detection second receiving coil 52 and the first detection third receiving coil 53 may be formed in multiple wiring layers of the substrate 30 and connected in series to increase the amplitude of the first voltage value V1 described later.

[0029] The second detection first receiving coil 61, the second detection second receiving coil 62, and the second detection third receiving coil 63 are each formed to form a closed-loop cosine wave in the normal direction and are arranged in order in the circumferential direction Dc. The second detection first receiving coil 61, the second detection second receiving coil 62, and the second detection third receiving coil 63 are connected in series. The second detection first receiving coil 61 is provided with lead-out wiring 64 for connection to the circuit board 100. The second detection first receiving coils 61 may be formed in multiple wiring layers of the substrate 30 and connected in series to increase the amplitude of the second voltage value V2 (described later). That is, although one period of the second detection first receiving coils 61 is shown in FIG. 3 , multiple second detection first receiving coils 61 may be formed in the thickness direction of the substrate 30 and connected in series. Similarly, the second receiving coil 62 for second detection and the third receiving coil 63 for second detection may be formed in multiple wiring layers of the substrate 30 and connected in series to increase the amplitude of the second voltage value V2 described later.

[0030] The first detection first receiving coil 51 and the second detection first receiving coil 61 are arranged in the same region of the substrate 30, and are configured by appropriately connecting different wiring layers through vias so as not to interfere with each other. More specifically, the first detection first receiving coil 51 and the second detection first receiving coil 61 have the same length in the circumferential direction Dc, and are formed so that both ends in the circumferential direction Dc coincide with the same imaginary lines K1 and K2 extending in the radial direction Dr from the rotation axis CL (i.e., the center CK of the substrate 30).

[0031] Similarly, the first detection second receiving coil 52 and the second detection second receiving coil 62 are arranged in the same region of the substrate 30, and are configured by appropriately connecting different wiring layers through vias so as not to interfere with each other. More specifically, the first detection second receiving coil 52 and the second detection second receiving coil 62 have the same length in the circumferential direction Dc, and are formed so that both ends in the circumferential direction Dc coincide with the same imaginary lines K3 and K4 extending from the rotation axis CL in the radial direction Dr.

[0032] The first third detection receiving coil 53 and the second third detection receiving coil 63 are arranged in the same region of the substrate 30, and are configured by appropriately connecting different wiring layers through vias so as not to interfere with each other. More specifically, the first third detection receiving coil 53 and the second third detection receiving coil 63 have the same length in the circumferential direction Dc, and are formed so that both ends in the circumferential direction Dc coincide with the same imaginary lines K5 and K6 extending from the rotation axis CL in the radial direction Dr.

[0033] In the following description, the first detection first receiver coil 51, the first detection second receiver coil 52, and the first detection third receiver coil 53 will also be collectively referred to as the first detection receiver coils 51 to 53. Similarly, the second detection first receiver coil 61, the second detection second receiver coil 62, and the second detection third receiver coil 63 will also be collectively referred to as the second detection receiver coils 61 to 63.

[0034] The first detection first receiver coil 51, the first detection second receiver coil 52, and the first detection third receiver coil 53 have the same length in the circumferential direction Dc so that they have the same facing area when facing each of the targets 22 to 26. Similarly, the second detection first receiver coil 61, the second detection second receiver coil 62, and the second detection third receiver coil 63 have the same length in the circumferential direction Dc so that they have the same facing area when facing each of the targets 22 to 26.

[0035] As will be described in detail later, in this embodiment, as the rotating member 20 rotates, the first detection first receiving coil 51, the first detection second receiving coil 52, and the first detection third receiving coil 53 generate a first voltage value V1 whose amplitude changes periodically. Also, as the rotating member 20 rotates, the second detection first receiving coil 61, the second detection second receiving coil 62, and the second detection third receiving coil 63 generate a second voltage value V2 whose amplitude changes periodically and has a different phase from the first voltage value V1. In this embodiment, the first voltage value V1 corresponds to a first signal, and the second voltage value V2 corresponds to a second signal.

[0036] In the present embodiment, the lengths of the targets 22-26 in the circumferential direction Dc and the lengths of the first detector coils 51-53 and the second detector coils 61-63 in the circumferential direction Dc are adjusted so that the amplitude of the first voltage value V1 and the amplitude of the second voltage value V2 are large. In the present embodiment, the lengths of the targets 22-26 in the circumferential direction Dc and the lengths of the first detector coils 51-53 and the second detector coils 61-63 in the circumferential direction Dc are adjusted so that the opposing area is half the period of the first detector coils 51-53 and the second detector coils 61-63. However, the lengths of the targets 22-26 in the circumferential direction Dc and the lengths of the first detector coils 51-53 and the second detector coils 61-63 in the circumferential direction Dc are not limited to this. For example, the circumferential length Dc of the targets 22 to 26 and the circumferential length Dc of the first detection receiving coils 51 to 53 and the second detection receiving coils 61 to 63 may be set so that the opposing area is 1 / 4 or 3 / 4 of the period of the first detection receiving coils 51 to 53 and the second detection receiving coils 61 to 63.

[0037] The first detection first receiving coil 51, the first detection second receiving coil 52, and the first detection third receiving coil 53 are connected in series, so that the first voltage values ​​V1 generated in the first detection first receiving coil 51, the first detection second receiving coil 52, and the first detection third receiving coil 53 are added together to form a single first detection voltage value AV1.

[0038] Similarly, the second detection first receiving coil 61, the second detection second receiving coil 62, and the second detection third receiving coil 63 are connected in series, so that the second voltage values ​​V2 generated in the second detection first receiving coil 61, the second detection second receiving coil 62, and the second detection third receiving coil 63 are added together to form a single second detection voltage value AV2.

[0039] In this embodiment, the first detection voltage value AV1 corresponds to the first detection signal value, and the second detection voltage value AV2 corresponds to the second detection signal value. As will be described in detail later, the first detection receiving coil 51, the second detection receiving coil 52, and the third detection receiving coil 53 are connected to the circuit board 100 via lead-out wiring 54. Similarly, the second detection receiving coil 61, the second detection receiving coil 62, and the third detection receiving coil 63 are connected to the circuit board 100 via lead-out wiring 64. The first detection voltage value AV1 to which the first voltage value V1 has been added and the second detection voltage value AV2 to which the second voltage value V2 has been added are also input to the circuit board 100.

[0040] Here, the first detection receiver coils 51-53 and the second detection receiver coils 61-63 of this embodiment are formed as described above. Therefore, if the region between the imaginary lines K1 and K2 in the circumferential direction Dc of the substrate 30 is defined as a first region R1, the first detection receiver coil 51 and the second detection receiver coil 61 can be said to be formed in the first region R1 of the substrate 30. Also, if the region between the imaginary lines K3 and K4 in the circumferential direction Dc of the substrate 30 is defined as a second region R2, the first detection receiver coil 52 and the second detection receiver coil 62 can be said to be formed in the second region R2 of the substrate 30. If the region between the imaginary lines K5 and K6 in the circumferential direction Dc of the substrate 30 is defined as a third region R3, the first detection receiver coil 53 and the second detection receiver coil 63 can be said to be formed in the third region R3 of the substrate 30. In this embodiment, the first region R1 and the third region R3 are configured to face each other across the rotation axis CL. The relationship between these regions is simply shown in FIG.

[0041] In the present embodiment, an example is shown in which the first region R1 and the second region R2 are connected in the circumferential direction Dc and the second region R2 and the third region R3 are connected in the circumferential direction Dc, but the first region R1 and the second region R2 may be spaced apart, or the second region R2 and the third region R3 may be spaced apart. That is, the virtual line K2 may be spaced apart from the virtual line K3, and the virtual line K4 may be spaced apart from the virtual line K5. When the first region R1 and the second region R2 are spaced apart in this manner, connection wiring may be provided between the first region R1 and the second region R2 to connect the first detection first receiving coil 51 and the second detection first receiving coil 61 to the first detection second receiving coil 52 and the second detection second receiving coil 62. Similarly, when the second region R2 and the third region R3 are separated, connection wiring can be provided between the second region R2 and the third region R3 to connect the first detection second receiving coil 52, the second detection second receiving coil 62, and the first detection third receiving coil 53, the second detection third receiving coil 63.

[0042] The circuit board 100 includes a microcomputer equipped with a CPU and storage units such as ROM, RAM, and nonvolatile RAM, and is connected to the transmitter coil 40, the first detection receiver coils 51-53, and the second detection receiver coils 61-63. The circuit board 100 realizes various control operations by the CPU reading and executing programs from the ROM or nonvolatile RAM. The ROM or nonvolatile RAM pre-stores various data (e.g., initial values, lookup tables, maps, etc.) used when executing the programs. The storage medium, such as the ROM, is a non-transient tangible storage medium. CPU stands for Central Processing Unit, ROM stands for Read Only Memory, and RAM stands for Random Access Memory.

[0043] Specifically, as shown in Fig. 6, the circuit board 100 includes a signal processing unit 110 that is connected to the transmitter coil 40, the first detection receiver coils 51 to 53, and the second detection receiver coils 61 to 63 and performs predetermined processing. The signal processing unit 110 includes an oscillator 111, a demodulator 112, an AD converter 113, an angle calculator 114, an output unit 115, a power supply unit 116, and the like. The processing of each unit will be described later. In the following, an example in which an analog signal is converted into a digital signal by the AD converter 113 and processed will be described as a representative example, but if processing is performed using an analog signal, the AD converter 113, etc. may not be provided.

[0044] The above is the configuration of the position detection device 10 in this embodiment. Next, the first voltage value V1 generated in the first detection first receiver coil 51, the first detection second receiver coil 52, and the first detection third receiver coil 53, and the second voltage value V2 generated in the second detection first receiver coil 61, the second detection second receiver coil 62, and the second detection third receiver coil 63 when the rotating member 20 rotates will be described. Note that the first detection first receiver coil 51, the first detection second receiver coil 52, and the first detection third receiver coil 53 have the same sine wave shape and are configured so that the areas facing the targets 22 to 26 are equal to each other. For this reason, the following description will be given using the first detection first receiver coil 51 as an example. Similarly, the second detection first receiving coil 61, the second detection second receiving coil 62, and the second detection third receiving coil 63 have the same cosine wave shape and are configured so that the areas facing the targets 22 to 26 are equal to each other. For this reason, the following description will be given taking the second detection first receiving coil 61 as an example.

[0045] First, an alternating current of a predetermined frequency is applied to the transmitter coil 40 from the oscillator 111, as will be described in detail later. This generates electromagnetic induction in the transmitter coil 40, which inductively couples the transmitter coil 40 with the first detection receiver coil 51 and the second detection receiver coil 61. This generates a magnetic field that passes through the area surrounded by the first detection receiver coil 51 and the second detection receiver coil 61 in the axial direction Da. Furthermore, because the magnetic field generated by the alternating current changes, the first voltage value V1 generated in the first detection receiver coil 51 and the second voltage value V2 generated in the second detection receiver coil 61 change due to electromagnetic induction.

[0046] When the targets 22 to 26 of the rotating member 20 face the first detection first receiving coil 51 and the second detection first receiving coil 61, eddy currents are generated in the targets 22 to 26, and a magnetic field resulting from the eddy currents is generated. Therefore, the magnetic field in the axial direction Da that passes through the area surrounded by the first detection first receiving coil 51 and the area surrounded by the second detection first receiving coil 61 and that passes through the portion facing the targets 22 to 26 is canceled out by the magnetic field resulting from the eddy currents. This causes a change in the first voltage value V1 generated in the first detection first receiving coil 51 and the second voltage value V2 generated in the second detection first receiving coil 61.

[0047] The targets 22 to 26 of the rotating member 20 are arranged side by side at intervals in the circumferential direction Dc, and therefore, as the rotating member 20 rotates, the facing areas of the first detection receiving coil 51 and the second detection receiving coil 61 and the targets 22 to 26 change periodically. Therefore, as the rotating member 20 rotates, the first voltage value V1 generated in the first detection receiving coil 51 and the second voltage value V2 generated in the second detection receiving coil 61 change periodically. In this embodiment, since the first detection receiving coil 51 is formed to have a sine wave shape, the first voltage value V1 generated in the first detection receiving coil 51 is demodulated to have a sine wave shape, as shown in FIG. 7A . Since the second detection receiving coil 61 is formed to have a cosine wave shape, the second voltage value V2 generated in the second detection receiving coil 61 is demodulated to have a cosine wave shape, as shown in FIG. 7B .

[0048] As described above, the first detection receiving coil 51, the first detection receiving coil 52, and the first detection receiving coil 53 have the same sine wave shape and are configured so that their facing areas with the targets 22-26 are equal to each other. Therefore, the first detection receiving coil 51, the first detection receiving coil 52, and the first detection receiving coil 53 generate the same first voltage value V1. Similarly, the second detection receiving coil 61, the second detection receiving coil 62, and the second detection receiving coil 63 have the same cosine wave shape and are configured so that their facing areas with the targets 22-26 are equal to each other. Therefore, the second detection receiving coil 61, the second detection receiving coil 62, and the second detection receiving coil 63 generate the same second voltage value V2. Note that the same voltage values ​​V1 and V2 here include some error due to manufacturing errors, etc.

[0049] As described above, the first detection first receiving coil 51, the first detection second receiving coil 52, and the first detection third receiving coil 53 are connected in series, so that the signal processing unit 110 (i.e., the circuit board 100) receives a single first detection voltage value AV1 obtained by adding together the first voltage values ​​V1 generated in the first detection first receiving coil 51, the first detection second receiving coil 52, and the first detection third receiving coil 53.

[0050] Similarly, the second detection first receiving coil 61, the second detection second receiving coil 62, and the second detection third receiving coil 63 are connected in series. Therefore, the signal processing unit 110 receives a single second detection voltage value AV2 obtained by adding together the second voltage values ​​V2 generated in the second detection first receiving coil 61, the second detection second receiving coil 62, and the second detection third receiving coil 63.

[0051] Next, the operation of the signal processing unit 110 in the circuit board 100 will be described.

[0052] 6 , the oscillator 111 is connected to both ends of the transmitting coil 40 and applies an AC current of a predetermined frequency. Two capacitors 117 and 118 are connected in series between both ends of the transmitting coil 40 and the oscillator 111, and the part connecting the two capacitors 117 and 118 is connected to ground. When an AC current is applied to the transmitting coil 40, the transmitting coil 40 generates a magnetic field in the axial direction Da that passes through the first detecting receiver coils 51-53 and the second detecting receiver coils 61-63, as described above. However, the manner in which the transmitting coil 40 and the oscillator 111 are connected can be changed as appropriate; for example, a single capacitor may be disposed between both ends of the transmitting coil 40 and the oscillator 111.

[0053] The demodulation unit 112 is connected to both ends of the part where the first detection first receiving coil 51, the first detection second receiving coil 52, and the first detection third receiving coil 53 are connected in series. Therefore, the demodulation unit 112 (i.e., the signal processing unit 110) receives a first detection voltage value AV1 obtained by adding together the first voltage values ​​V1 generated in the first detection first receiving coil 51, the first detection second receiving coil 52, and the first detection third receiving coil 53. Therefore, in this embodiment, the amplitude of the signal input to the demodulation unit 112 can be increased, and the S / N ratio can be increased.

[0054] Similarly, the demodulation unit 112 is connected to both ends of a portion where the second detection first receiving coil 61, the second detection second receiving coil 62, and the second detection third receiving coil 63 are connected in series. Therefore, the demodulation unit 112 (i.e., the signal processing unit 110) receives a second detection voltage value AV2 obtained by adding the second voltage value V2 generated in the second detection first receiving coil 61, the second detection second receiving coil 62, and the second detection third receiving coil 63. Therefore, in this embodiment, the amplitude of the signal input to the demodulation unit 112 can be increased, and the S / N ratio can be increased.

[0055] For example, a comparative position detection device is one in which one first detection receiver coil and one second detection receiver coil are arranged on the substrate 30. In the position detection device 10 having three first detection receiver coils 51-53 and three second detection receiver coils 61-63 connected in series as in this embodiment, a voltage having three times the amplitude is input to the signal processing unit 110 as shown in Fig. 8 compared to the comparative position detection device. This allows for a larger S / N ratio.

[0056] The demodulation unit 112 then demodulates the first detected voltage value AV1 to generate a first demodulated signal VD1, as shown in Fig. 6. Similarly, the demodulation unit 112 demodulates the second detected voltage value AV2 to generate a second demodulated signal VD2. In this embodiment, the first demodulated signal VD1 is a sine wave signal as shown in Fig. 7A, and the second demodulated signal VD2 is a cosine wave signal as shown in Fig. 7B.

[0057] The AD conversion unit 113 is connected to the demodulation unit 112 and the angle calculation unit 114. The AD conversion unit 113 outputs to the angle calculation unit 114 a first converted signal Si obtained by AD converting the first demodulation signal VD1 and a second converted signal Co obtained by AD converting the second demodulation signal VD2.

[0058] The angle calculation unit 114 calculates an arctangent (i.e., arc tangent) function based on the first converted signal Si and the second converted signal Co to derive tan θ, and calculates the rotation angle θ (i.e., position) of the rotating member 20 based on the derived tan θ. At this time, correction may be made to reduce a phase change or the like according to the gap g between the rotating member 20 and the substrate 30, as necessary.

[0059] The output unit 115 is connected to the angle calculation unit 114 and outputs the rotation angle θ calculated by the angle calculation unit 114 to an external circuit.

[0060] The power supply unit 116 is connected to the individual units 111 to 115 of the signal processing unit 110 and supplies power to the individual units 111 to 115 .

[0061] Next, the operation and effects of the position detection device 10 will be described, and the configuration will be explained in more detail.

[0062] As described above, the position detection device 10 is provided such that the substrate 30 faces the targets 22-26 of the rotating member 20 in the axial direction Da. When the rotating member 20 rotates while an AC current is applied to the transmitter coil 40, the first voltage value V1 of the first detection receiver coils 51-53 and the second voltage value V2 of the second detection receiver coils 61-63 periodically change. In this embodiment, the first detection receiver coils 51-53 are connected in series, and the second detection receiver coils 61-63 are connected in series. Therefore, the signal processing unit 110 receives a first detection voltage value AV1 obtained by adding the first voltage value V1 of the first detection receiver coils 51-53, and a second detection voltage value AV2 obtained by adding the second voltage value V2 of the second detection receiver coils 61-63. This increases the signal-to-noise ratio, improving detection accuracy.

[0063] In this embodiment, the first detection receiver coils 51 to 53 and the second detection receiver coils 61 to 63 are arranged in the circumferential direction Dc and connected in series, as described above, which can reduce errors due to substrate misalignment.

[0064] For example, as shown in FIG. 9A , assume that one direction in the plane of the substrate 30 is the X-axis direction, and the direction perpendicular to the X-axis direction is the Y-axis direction. As a result of the substrate 30 being displaced in the X-axis direction, the center CK of the substrate 30 and the rotation axis CL are displaced in the X-axis direction. Note that in FIG. 9A , the left-right direction on the paper is the X-axis direction, and the up-down direction on the paper is the Y-axis direction. In this embodiment, three first detection receiver coils 51-53 and three second detection receiver coils 61-63 are arranged side by side in the circumferential direction Dc. That is, in this embodiment, the first to third regions R1-R3 are arranged side by side in the circumferential direction Dc. In this case, the first region R1 and the third region R3 are less affected by the misalignment because the direction of the misalignment intersects with the rotation direction, while the second region R2 is more affected by the misalignment because the direction of the misalignment is the same as the rotation direction. However, in this embodiment, the first detection receiving coils 51 to 53 are connected in series, and the second detection receiving coils 61 to 63 are connected in series. This reduces the influence of noise caused by substrate misalignment contained in the first detection voltage value AV1, and reduces the influence of noise caused by substrate misalignment contained in the second detection voltage value AV2. This reduces the influence of noise caused by substrate misalignment.

[0065] 9B , for example, assume that the substrate 30 is misaligned in the Y-axis direction, causing the center CK of the substrate 30 and the rotation axis CL to be misaligned in the Y-axis direction. In this case, the second region R2 is less affected by the misalignment because the direction of misalignment intersects the rotation direction, while the first region R1 and the third region R3 are more affected by the misalignment because the direction of misalignment is aligned with the rotation direction. However, the first region R1 and the third region R3 are affected by the misalignment in the opposite way. Therefore, the first voltage value V1 from the first region R1 and the first voltage value V2 from the third region R3 are added together, canceling out the noise caused by the misalignment. Similarly, the second voltage value V2 from the first region R1 and the second voltage value V2 from the third region R3 are added together, canceling out the noise caused by the misalignment. Therefore, the noise caused by the substrate misalignment can be reduced.

[0066] According to the inventors' investigations, when the first detection receiver coils 51-53 and the second detection receiver coils 61-63 are formed as in this embodiment, the angular accuracy with respect to substrate misalignment in the X-axis direction is confirmed to be 2.2°pp, as shown in FIG. 10 . On the other hand, in a comparative position detection device equipped with one first detection receiver coil 51 and one second detection receiver coil 61, the angular accuracy with respect to substrate misalignment in the X-axis direction is confirmed to be 6.5°pp, as shown in FIG. 11 . Similar results were obtained for the angular accuracy with respect to substrate misalignment in the Y-axis direction, although details are omitted. Therefore, it is confirmed that forming the first detection receiver coils 51-53 and the second detection receiver coils 61-63 as in this embodiment can adequately address substrate misalignment. Note that FIG. 10 also shows the results of reducing the influence of the end of the transmitter coil 40, which will be described later. Therefore, the angular accuracy in FIGS. 10 and 11 differs even when there is no substrate misalignment.

[0067] Furthermore, when the transmitter coil 40 is formed in the shape of an arc frame with the circumferential direction Dc as the longitudinal direction, as in this embodiment, the portion extending in the circumferential direction Dc and the portion extending in the radial direction Dr are arranged close to each other at the ends in the longitudinal direction. Therefore, inside the transmitter coil 40, the magnetic field tends to be stronger in the portions at both ends in the longitudinal direction than in the portion closer to the center, and offset errors tend to be included.

[0068] For this reason, in this embodiment, the transmitter coil 40 is formed so as to collectively surround the first detection receiver coils 51 to 53 and the second detection receiver coils 61 to 63. This makes it possible to reduce the influence of noise caused by the ends of the transmitter coil 40 compared to a case in which a transmitter coil 40 surrounding the first detection receiver coil 51 and the second detection receiver coil 61, a transmitter coil 40 surrounding the first detection receiver coil 52 and the second detection receiver coil 62, and a transmitter coil 40 surrounding the first detection receiver coil 53 and the second detection receiver coil 63 are separately provided.

[0069] The inventors further conducted extensive research into the influence of the ends of the transmitter coil 40 and obtained the results shown in FIG. 12. Note that FIG. 12 shows the results of a study using the model shown in FIG. 13, in which the transmitter coil 40 is arranged to surround the first detector coils 51-53 and the second detector coils 61-63. In this model, the angle formed by the imaginary lines K10 and K11 passing through the ends of the first detector coils 51-53 and the second detector coils 61-63 in the circumferential direction Dc and extending from the rotation axis CL in the radial direction Dr is defined as the receiver coil forming angle θ1, and this θ1 is set to 216°. In this model, the angle formed by the imaginary lines K20 and K21 passing through the ends of the transmitter coil 40 in the circumferential direction Dc and extending from the rotation axis CL in the radial direction Dr is defined as the transmitter coil forming angle θ2. In this model, the angle between the virtual lines K10 and K11 and the virtual lines K20 and K21 is the separation angle θ3. Fig. 12 shows the results of changing the separation angle θ3 by changing the forming angle θ2 of the transmitting coil 40.

[0070] As shown in Figure 12, it is confirmed that the angular error decreases sharply as the separation angle θ3 increases when the separation angle θ3 is in the range of 5° or less. It is also confirmed that the angular error decreases gradually when the separation angle θ3 is in the range of 5 to 10°, and becomes almost constant when the separation angle θ3 is 10° or more. Note that even if the forming angle θ1 of the receiving coil is changed, the relationship between the separation angle θ3 and the angular error does not change.

[0071] That is, it has been confirmed that the angular error is reduced by forming the first detection receiver coils 51 to 53 and the second detection receiver coils 61 to 63 at positions 5° or more away from the virtual lines K20 and K21 in the circumferential direction Dc. It has also been confirmed that the angular error is sufficiently reduced by forming the first detection receiver coils 51 to 53 and the second detection receiver coils 61 to 63 at positions 10° or more away from the virtual lines K20 and K21 in the circumferential direction Dc.

[0072] Therefore, in this embodiment, the transmitter coil 40 is formed in an arc-shaped frame shape, and its ends in the circumferential direction Dc are aligned with imaginary lines K20 and K21 extending from the rotation axis CL in the radial direction Dr. The first and second detection receiver coils 51 and 61, and the first and second detection receiver coils 53 and 63, are preferably formed at a distance of 5° or more in the circumferential direction Dc from the ends of the transmitter coil 40 in the circumferential direction Dc. More preferably, the first and second detection receiver coils 51 and 61, and the first and second detection receiver coils 53 and 63 are formed at a distance of 10° or more in the circumferential direction Dc from the ends of the transmitter coil 40 in the circumferential direction Dc. This reduces the influence of the ends of the transmitter coil 40 in the circumferential direction Dc, thereby reducing angle errors. However, if the first detection first receiver coil 51 and the second detection first receiver coil 61, and the first detection third receiver coil 53 and the second detection third receiver coil 63 are located too far away from the end of the transmitter coil 40 in the circumferential direction Dc, an excess area will increase. For this reason, it is preferable that the maximum value of the separation angle θ3 be set appropriately depending on the shape of the substrate 30 to be used, etc.

[0073] Incidentally, as described above, the substrate 30 of this embodiment has a shape having an arc portion and two ends 31, 32 in the circumferential direction Dc. Therefore, as shown in Fig. 14, when preparing the substrate 30 by cutting it out from a substrate constituent plate 300 for forming the substrate 30, it is possible to reduce unnecessary portions of the substrate constituent plate 300 compared to, for example, a case in which the substrate 30 is a complete ring, that is, a roughly O-shape. Therefore, it is possible to improve the yield when preparing the substrate 30, and ultimately to reduce costs.

[0074] According to the present embodiment described above, the first detection first receiving coil 51, the first detection second receiving coil 52, and the first detection third receiving coil 53, which generate the first voltage value V1, are connected in series. Furthermore, the second detection first receiving coil 61, the second detection second receiving coil 62, and the second detection third receiving coil 63, which generate the second voltage value V2, are connected in series. Therefore, the signal processing unit 110 receives the first detection voltage value AV1 to which the first voltage value V1 has been added, and also receives the second detection voltage value AV2 to which the second voltage value V2 has been added. Therefore, the influence of noise can be reduced, thereby increasing the signal-to-noise ratio and improving detection accuracy.

[0075] (1) In this embodiment, the first detection receiver coils 51 to 53 are formed as closed-loop sine waves, and the second detection receiver coils 61 to 63 are formed as closed-loop cosine waves. This allows the use of coil shapes that have been used in the past, and allows for easy design changes.

[0076] (2) In the present embodiment, the coil 40 is formed to collectively surround the first detection receiver coils 51 to 53 and the second detection receiver coils 61 to 63. Therefore, compared to a case in which a transmitter coil 40 surrounding the first detection receiver coil 51 and the first second detection receiver coil 61, a transmitter coil 40 surrounding the first detection receiver coil 52 and the second detection receiver coil 62, and a transmitter coil 40 surrounding the first detection receiver coil 53 and the second detection receiver coil 63 are separately provided, the influence of noise caused by the ends of the transmitter coil 40 can be reduced.

[0077] (3) In the present embodiment, the first detection first receiver coil 51 and the second detection first receiver coil 61, and the first detection third receiver coil 53 and the second detection third receiver coil 63 are formed at a distance of 5° or more in the circumferential direction Dc from the end of the transmitter coil 40 in the circumferential direction Dc, thereby reducing the influence of the end of the transmitter coil 40 in the circumferential direction Dc. In this case, the first detection first receiver coil 51 and the second detection first receiver coil 61, and the first detection third receiver coil 53 and the second detection third receiver coil 63 are formed at a distance of 10° or more in the circumferential direction Dc from the end of the transmitter coil 40 in the circumferential direction Dc, thereby sufficiently reducing the influence of the end of the transmitter coil 40 in the circumferential direction Dc.

[0078] (4) In this embodiment, the substrate 30 has an arc portion along the circumferential direction Dc and has two ends 31, 32 in the circumferential direction Dc. This improves the yield when cutting out the substrates 30 from the substrate component plate 300.

[0079] (Modification of First Embodiment) A modification of the first embodiment will be described. In the first embodiment, an example has been described in which three first detection receiver coils 51 to 53 and three second detection receiver coils 61 to 63 are provided. However, the number of first detection receiver coils and second detection receiver coils may be four or more.

[0080] In the first embodiment, an example has been described in which a transmitter coil 40 different from the receiver coil is provided. However, the first detector receiver coils 51 to 53 and the second detector receiver coils 61 to 63 may be used as the transmitter coil 40. In other words, the transmitter coil and the receiver coil may be formed by a common coil.

[0081] Furthermore, in the first embodiment, the first region R1 and the third region R3 are configured to face each other across the rotation axis CL, as shown in FIG. 5. However, the first region R1 and the third region R3 do not have to be configured to face each other across the rotation axis CL. That is, the first to third regions R1 to R3 may be arranged in a portion of the substrate 30 having an arc portion, the portion having a length in the circumferential direction Dc that is shorter than the length of the semicircular arc.

[0082] In the first embodiment, the substrate 30 does not have to have the ends 31, 32 in the circumferential direction Dc. In other words, the substrate 30 may be formed in an annular shape.

[0083] Second Embodiment A second embodiment will be described. This embodiment differs from the first embodiment in that the configurations of the first detection receiver coils 51 to 53 and the second detection receiver coils 61 to 63 are changed. As the rest of the configuration is the same as the first embodiment, a description thereof will be omitted here.

[0084] In the first embodiment, a configuration was described in which the first detector coils 51-53 are sine-wave shaped and the second detector coils 61-63 are cosine-wave shaped. However, the shapes of the first detector coils 51-53 and the second detector coils 61-63 are not limited to this. For example, the first detector coils 51-53 and the second detector coils 61-63 may be spiral shaped. In this embodiment, a configuration in which the first detector coils 51-53 and the second detector coils 61-63 are spiral shaped will be described. Note that the rotating member 20 in this embodiment is configured to have four targets 22-24. However, the number of targets 22-24 on the rotating member 20 is not limited to this. As in the first embodiment, the rotating member 20 may have five targets 22-26.

[0085] 15 and 16 , in the first region R1, a first spiral portion 51 a and a second spiral portion 51 b connected in series are formed as a first detection first receiving coil 51. Also, in the first region R1, a first spiral portion 61 a and a second spiral portion 61 b ​​connected in series are formed as a second detection first receiving coil 61.

[0086] Similarly, the second region R2 has a first spiral portion 52a and a second spiral portion 52b connected in series as the first detection second receiving coil 52. Also, the second region R2 has a first spiral portion 62a and a second spiral portion 62b connected in series as the second detection second receiving coil 62.

[0087] In the third region R3, a first spiral portion 53a and a second spiral portion 53b connected in series are formed as a first detection third receiving coil 53. In addition, in the third region R3, a second detection third receiving coil 63, a first spiral portion 63a and a second spiral portion 63b connected in series are formed.

[0088] Each of the first spiral portions 51a, 61a, 52a, 62a, 53a, and 63a and each of the second spiral portions 51b, 61b, 52b, 62b, 53b, and 63b has a spiral pattern formed to draw a square with varying diameters. Each of the first spiral portions 51a, 61a, 52a, 62a, 53a, and 63a and each of the second spiral portions 51b, 61b, 52b, 62b, 53b, and 63b is formed by winding a coil multiple times in the same direction in each of the multiple wiring layers of the substrate 30. Each of the first spiral portions 51a, 61a, 52a, 62a, 53a, and 63a and each of the second spiral portions 51b, 61b, 52b, 62b, 53b, and 63b formed in each of the multiple wiring layers of the substrate 30 is formed to overlap in the normal direction. However, the first spiral portions 51 a, 61 a, 52 a, 62 a, 53 a, 63 a and the second spiral portions 51 b, 61 b, 52 b, 62 b, 53 b, 63 b have coil winding directions (i.e., spiral directions) opposite to each other. Note that, although the first spiral portions 51 a, 61 a, 52 a, 62 a, 53 a, 63 a and the second spiral portions 51 b, 61 b, 52 b, 62 b, 53 b, 63 b have rectangular outer shapes in the above example, they may have circular outer shapes, etc.

[0089] In the first region R1, the first spiral portion 51a, the first spiral portion 61a, the second spiral portion 51b and the second spiral portion 61b are formed in this order from one end 32 to the other end 31 in the circumferential direction Dc of the substrate 30.

[0090] Similarly, in the second region R2, the first spiral portion 52a, the first spiral portion 62a, the second spiral portion 52b and the second spiral portion 62b are formed in this order from one end 32 to the other end 31 in the circumferential direction Dc of the substrate 30.

[0091] In addition, in the third region R3, the first spiral portion 53a, the first spiral portion 63a, the second spiral portion 53b and the second spiral portion 63b are formed in this order along the circumferential direction Dc of the substrate 30 from one end 32 to the other end 31.

[0092] As in the first embodiment, as the rotating member 20 rotates, the first detecting coils 51 to 53 generate a first voltage V1 whose amplitude changes periodically according to the area facing the targets 22 to 25. As the rotating member 20 rotates, the second detecting coils 61 to 63 generate a second voltage V2 whose amplitude changes periodically and has a different phase from the first voltage V1.

[0093] As described above, the rotating member 20 of this embodiment has four targets 22 to 25, which are arranged at 90° intervals in the circumferential direction Dc. The length of each of the targets 22 to 25 in the circumferential direction Dc is adjusted so that each of the targets 22 to 25 faces three of the four spiral portions arranged in the first to third regions R1 to R3, so that the amplitude of the first voltage value V1 and the amplitude of the second voltage value V2 are large. In other words, the length of each of the first spiral portions 51 a, 61 a, 52 a, 62 a, 53 a, and 63 a and each of the second spiral portions 51 b, 61 b, 52 b, 62 b, 53 b, and 63 b in the first to third regions R1 to R3 in the circumferential direction Dc is adjusted so that three of the targets 22 to 26 face each of the targets 22 to 26 in each of the regions R1 to R3.

[0094] In this embodiment, the first and second spiral portions 51 a, 51 b in the first region R1, the first and second spiral portions 52 a, 52 b in the second region R2, and the first and second spiral portions 53 a, 53 b in the third region R3 are connected in series. Similarly, the first and second spiral portions 61 a, 61 b ​​in the first region R1, the first and second spiral portions 62 a, 62 b in the second region R2, and the first and second spiral portions 63 a, 63 b in the third region R3 are connected in series.

[0095] Therefore, similarly to the first embodiment, the first voltage values ​​V1 are added together to form a single first detected voltage value AV1, and the second voltage values ​​V2 are added together to form a single second detected voltage value AV2. Since the first detected voltage value AV1 and the second detected voltage value AV2 are input to the signal processing unit 110, the S / N ratio can be increased.

[0096] As described above, even if the first detection receiver coils 51 to 53 and the second detection receiver coils 61 to 63 are formed in a spiral shape, the same effects as those of the first embodiment can be obtained. Furthermore, by forming the first detection receiver coils 51 to 53 and the second detection receiver coils 61 to 63 in a spiral shape, it becomes easier to increase the facing area with the targets 22 to 25, which makes it easier to further increase the amplitudes of the first detection voltage value AV1 and the second detection voltage value AV2.

[0097] (Modification of Second Embodiment) A modification of the second embodiment will be described. In the second embodiment, an example has been described in which the lengths of the targets 22 to 25 in the circumferential direction Dc are adjusted so that they face three of the four spiral portions arranged in the first to third regions R1 to R3, so that the amplitude of the first voltage value V1 and the amplitude of the second voltage value V2 are increased. However, in order to increase the amplitude of the first voltage value V1 and the amplitude of the second voltage value V2, as shown in FIG. 17 , the lengths of the targets 22 to 25 in the circumferential direction Dc may be adjusted so that they face one of the four spiral portions arranged in the first to third regions R1 to R3. In other words, the lengths of the first spiral portions 51a, 61a, 52a, 62a, 53a, 63a and the second spiral portions 51b, 61b, 52b, 62b, 53b, 63b in the first to third regions R1 to R3 may be adjusted in the circumferential direction Dc so that one spiral portion faces the target 22 to 25 in each region R1 to R3.

[0098] Third Embodiment A third embodiment will be described. This embodiment is different from the first embodiment in that the configuration of the transmission coil 40 is changed. As the rest of the configuration is the same as the first embodiment, a description thereof will be omitted here.

[0099] In this embodiment, as shown in Fig. 18, three transmitter coils 40 are formed: a first transmitter coil 40a, a second transmitter coil 40b, and a third transmitter coil 40c. Although Fig. 18 is a simplified illustration, a first detection first receiver coil 51 and a second detection first receiver coil 61 are formed in the first region R1, as in Fig. 5. Similarly, a first detection second receiver coil 52 and a second detection second receiver coil 62 are formed in the second region R2. A first detection third receiver coil 53 and a second detection third receiver coil 63 are formed in the third region R3.

[0100] The first transmitter coil 40a is formed so as to surround the first region R1. In other words, the first transmitter coil 40a is formed so as to surround the first detection receiver coil 51 and the second detection receiver coil 61.

[0101] The second transmitter coil 40b is formed so as to surround the second region R2. In other words, the second transmitter coil 40b is formed so as to surround the first detection second receiver coil 52 and the second detection second receiver coil 62.

[0102] The third transmitter coil 40c is formed so as to surround the third region R3. In other words, the third transmitter coil 40c is formed so as to surround the first third detection receiver coil 53 and the second third detection receiver coil 63.

[0103] As in the first embodiment, the first detection first receiving coil 51, the first detection second receiving coil 52, and the first detection third receiving coil 53 are connected in series. Also, the second detection first receiving coil 61, the second detection second receiving coil 62, and the second detection third receiving coil 63 are connected in series. Therefore, also in this embodiment, the signal processing unit 110 receives a single first detection voltage value AV1 to which the first voltage value V1 has been added, and a single second detection voltage value AV2 to which the second voltage value V2 has been added.

[0104] According to the present embodiment described above, the first detection receiving coils 51 to 53 are connected in series and the second detection receiving coils 61 to 63 are connected in series, so that the same effects as those of the first embodiment can be obtained.

[0105] (Modification of the Third Embodiment) A modification of the third embodiment will be described. In the third embodiment, the configuration in which the regions R1 to R3 are surrounded by separate transmitter coils 40a to 40c has been described. However, for example, the first region R1 and the second region R2 may be surrounded by a single transmitter coil 40, and the third region R3 may be surrounded by a separate transmitter coil 40.

[0106] Fourth Embodiment A fourth embodiment will be described. This embodiment is different from the first embodiment in that the shape of the substrate 30 is changed. As the rest of the fourth embodiment is the same as the first embodiment, a description thereof will be omitted here.

[0107] In this embodiment, as shown in Figure 19, the substrate 30 has a detection area 33 in which the transmitting coil 40, first detecting receiving coils 51 to 53, and second detecting receiving coils 61 to 63 are arranged, and a mounting area 34 connected to the detection area 33.

[0108] Specifically, the detection area 33 is an arc portion formed along the circumferential direction Dc of the rotation axis CL. The mounting area 34 is an area that protrudes outward from the outer edge of the detection area 33 along the surface direction of the substrate 30. The circuit board 100 is disposed in the mounting area 34. Note that electronic components, terminals, etc. may be disposed in the mounting area 34 in the same manner as the circuit board 100, or may be disposed in the detection area 33.

[0109] According to the present embodiment described above, the first detection receiving coils 51 to 53 are connected in series and the second detection receiving coils 61 to 63 are connected in series, so that the same effects as those of the first embodiment can be obtained.

[0110] (1) In this embodiment, the substrate 30 has a detection area 33 and a mounting area 34, and the circuit board 100 is disposed in the mounting area 34. Therefore, compared to disposing the circuit board 100 in the detection area 33, there is no need to adjust the positional relationship between the circuit board 100 and the transmitter coil 40, the first detector receiver coils 51 to 53, and the second detector receiver coils 61 to 63, thereby improving the degree of freedom in mounting the circuit board 100. Furthermore, electromagnetic waves and the like that may be generated from the circuit board 100 are less likely to affect the transmitter coil 40, the first detector receiver coils 51 to 53, and the second detector receiver coils 61 to 63, thereby improving detection accuracy.

[0111] Fifth Embodiment A fifth embodiment will be described. In this embodiment, first detection receiver coils 51, 53 and second detection receiver coils 61, 63 are formed in two regions R1, R3 in comparison with the first embodiment. As the rest of the configuration is the same as the first embodiment, a description thereof will be omitted here.

[0112] First, European Patent No. 3792599 proposes a position detection device for detecting the rotation angle of a shaft member. Specifically, in this position detection device, a rotating member is coupled to the shaft member so as not to rotate relative to the shaft member, and the rotating member rotates integrally with the shaft member as the shaft member rotates. Also, in this position detection device, an arc-shaped substrate is disposed facing the rotating member. A first sine-wave receiving coil and a second cosine-wave receiving coil are formed on the substrate. More specifically, in this position detection device, the first receiving coil and the second receiving coil are disposed in opposing regions of the substrate across the shaft member.

[0113] In addition, in this rotation angle detection device, two arc-frame-shaped transmitter coils with their longitudinal direction aligned with the circumferential direction of the substrate are arranged to surround the first and second receiver coils formed in each region. In other words, in this position detection device, two transmitter coils are arranged to separately surround the first and second receiver coils formed in each region.

[0114] However, at the longitudinal end portions of the transmitter coil, the circumferentially extending portion of the shaft member and the radially extending portion of the shaft member are arranged close to each other. Therefore, according to the inventors' investigation, it was confirmed that, inside the transmitter coil, the magnetic field tends to be stronger at both circumferentially extending end portions than at the central portion, and offset errors are likely to occur. In other words, the detection accuracy of this position detection device may be easily reduced.

[0115] Therefore, an object of this embodiment is to provide a position detection device that can prevent a decrease in detection accuracy.

[0116] 20, the position detection device 10 of this embodiment has first detection receiver coils 51, 53 and second detection receiver coils 61, 63 formed in the first region R1 and the third region R3. In this embodiment, the first region R1 and the third region R3 are arranged to face each other with the rotation axis CL (i.e., the center CK of the substrate 30) in between.

[0117] The transmitter coil 40 is formed so as to surround the first detection first receiver coil 51 and the second detection first receiver coil 61 formed in the first region R1, and the first detection third receiver coil 53 and the second detection third receiver coil 63 formed in the third region R3. In other words, the first detection first receiver coil 51 and the second detection first receiver coil 61 formed in the first region R1, and the first detection third receiver coil 53 and the second detection third receiver coil 63 formed in the third region R3 are surrounded by the same transmitter coil 40.

[0118] In this embodiment, the first detection first receiving coil 51 and the first detection third receiving coil 53 are connected in series, and the second detection first receiving coil 61 and the second detection third receiving coil 63 are connected in series. However, in this embodiment, the first detection first receiving coil 51 and the first detection third receiving coil 53 may not be connected in series, and the first voltage value V1 may be input to the circuit board 100 from the first detection first receiving coil 51 and the first detection third receiving coil 53, respectively. Similarly, the second detection first receiving coil 61 and the second detection third receiving coil 63 may not be connected in series, and the second voltage value V2 may be input to the circuit board 100 from the second detection first receiving coil 61 and the second detection third receiving coil 63, respectively.

[0119] According to the present embodiment described above, the first detection first receiver coil 51 and the second detection first receiver coil 61 formed in the first region R1, and the first detection third receiver coil 53 and the second detection third receiver coil 63 formed in the third region R3 are surrounded by the same transmitter coil 40. This reduces the influence of the ends of the transmitter coil 40 in the circumferential direction Dc, and prevents a decrease in detection accuracy.

[0120] In this case, similarly to the first embodiment, the first detection first receiver coil 51 and the second detection first receiver coil 61 and the first detection third receiver coil 53 and the second detection third receiver coil 63 are formed at a distance of 5° or more in the circumferential direction Dc from the end of the transmitter coil 40 in the circumferential direction Dc, thereby further reducing the influence of the end of the transmitter coil 40 in the circumferential direction Dc. Furthermore, the first detection first receiver coil 51 and the second detection first receiver coil 61 and the first detection third receiver coil 53 and the second detection third receiver coil 63 are formed at a distance of 10° or more in the circumferential direction Dc from the end of the transmitter coil 40 in the circumferential direction Dc, thereby sufficiently reducing the influence of the end of the transmitter coil 40 in the circumferential direction Dc.

[0121] (Summary of Fifth Embodiment) The fifth embodiment is configured as described above. Therefore, in summary, it can be said that the fifth embodiment has the following advantages.

[0122] (Aspect 1) A position detection device comprising: a rotating member (20) that rotates around a rotation axis (CL) of a shaft member (70); a substrate (30) that has an arc portion along a circumferential direction (Dc) of the rotation axis and has regions that face each other across the rotation axis, and is disposed opposite the rotating member; a first detection receiving coil (51, 53) that is formed on the substrate and generates a first signal having periodicity corresponding to a change in a magnetic field caused by the rotation of the rotating member; a second detection receiving coil (61, 63) that is formed on the substrate and generates a second signal (V2) that has periodicity corresponding to a change in a magnetic field caused by the rotation of the rotating member and that is out of phase with the first signal; and a transmitting coil (40) that generates a magnetic field that passes through the first detection receiving coil and the second detection receiving coil when an alternating current is applied, wherein the first detection receiving coil and the second detection receiving coil are formed in respective regions of the substrate that face each other across the rotation axis, A position detection device in which the transmitting coil is formed to collectively surround the first detecting receiving coil and the second detecting receiving coil, which are formed in respective areas of the substrate that face each other across the rotation axis.

[0123] (Aspect 2) The position detection device according to Aspect 1, wherein the transmitting coil is an arc-shaped frame with its longitudinal direction aligned with the circumferential direction of the substrate, and the first detecting receiving coil and the second detecting receiving coil are formed at positions spaced apart from each other in the circumferential direction by 5° or more from imaginary lines (K20, K21) that pass through the circumferential ends of the transmitting coil and extend in a direction perpendicular to the rotation axis.

[0124] (Aspect 3) The position detection device according to Aspect 2, wherein the first detection receiver coil and the second detection receiver coil are formed at positions spaced apart from the imaginary line by 10° or more in the circumferential direction.

[0125] (Other Embodiments) While the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0126] For example, the position detection device 10 in each of the above embodiments may be mounted on a device other than a vehicle.

[0127] In addition, in each of the above embodiments, an example has been described in which the signal processing unit 110 is provided on the circuit board 100. However, the signal processing unit 110 may be provided separately from the circuit board 100, and may not be disposed on the substrate 30.

[0128] In each of the above embodiments, the number of targets on the rotating member 20 can be changed as appropriate. For example, when the number of targets is four, the targets are arranged at 90° intervals in the circumferential direction Dc as described above. When the number of targets is five, the targets are arranged at 72° intervals in the circumferential direction Dc as described above. When the number of targets is six, the targets are arranged at 60° intervals in the circumferential direction Dc. When the number of targets is eight, the targets are arranged at 45° intervals in the circumferential direction Dc. When the number of targets is twelve, the targets are arranged at 30° intervals in the circumferential direction Dc.

[0129] Furthermore, in the above first to fourth embodiments, the first detection first receiving coil 51 and the second detection first receiving coil 61, and the first detection third receiving coil 53 and the second detection third receiving coil 63 do not have to be formed more than 5° away from the end of the transmitting coil 40 in the circumferential direction Dc.

[0130] The above embodiments can also be combined. For example, the second embodiment can be combined with the third to fifth embodiments, so that the first detection receiver coils 51 to 53 and the second detection receiver coils 61 to 63 are spirally wound. The third embodiment can also be combined with the fourth embodiment, so that the transmitter coil 40 is formed to surround the first detection receiver coils 51 to 53 and the second detection receiver coils 61 to 63 formed in the regions R1 to R3, respectively. Furthermore, the fourth embodiment can be combined with the fifth embodiment, so that the substrate 30 has a detection region 33 and a mounting region 34. Combinations of the above embodiments can also be combined.

[0131] The controller (i.e., circuit board 100) and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the controller and methods described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the controller and methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0132] [Disclosure of the Present Invention] The present disclosure described above can be understood from the following viewpoints, for example.

[0133] [First Aspect] A position detection device comprising: a rotating member (20) that rotates around a rotation axis (CL) of a shaft member (70); a substrate (30) that is shaped to have an arc portion along a circumferential direction (Dc) of the rotation axis and that is arranged opposite the rotating member; first detection receiver coils (51-53) that are formed on the substrate and generate a first signal (V1) having periodicity corresponding to a change in a magnetic field caused by the rotation of the rotating member; second detection receiver coils (61-63) that are formed on the substrate and generate a second signal (V2) that has periodicity corresponding to a change in a magnetic field caused by the rotation of the rotating member and that is out of phase with the first signal; and a signal processing unit (110) that detects a rotation angle of the rotating member, wherein three or more of the first detection receiver coils are provided along the circumferential direction of the substrate and are connected in series; and three or more of the second detection receiver coils are provided along the circumferential direction of the substrate and are connected in series, The signal processing unit receives a first detection signal value (AV1) obtained by adding together the first signals generated in the plurality of first detection receiving coils, and a second detection signal value (AV2) obtained by adding together the second signals generated in the plurality of second detection receiving coils, and the signal processing unit is a position detection device that detects the angle of the rotating member based on the first detection signal value and the second detection signal value.

[0134] [Second Aspect] A position detection device according to the first aspect, wherein the first detection receiver coil is formed as a closed-loop sine wave in a normal direction to the surface direction of the substrate, and the second detection receiver coil is formed as a cosine wave in the normal direction.

[0135] [Third Aspect] The position detection device according to the first aspect, wherein the first detection receiver coil is spirally shaped in a normal direction to the surface direction of the substrate, and the second detection receiver coil is spirally shaped in the normal direction.

[0136] [Fourth Aspect] A position detection device according to any one of the first to third aspects, which includes transmitting coils (40a to 40c) that generate a magnetic field that passes through the first detecting receiving coil and the second detecting receiving coil when an alternating current is applied, and wherein the transmitting coils are formed in plurality so as to surround one of the first detecting receiving coil and one of the second detecting receiving coil.

[0137] [Fifth Aspect] A position detection device according to any one of the first to third aspects, comprising a transmitting coil (40) that generates a magnetic field that passes through the first detecting receiving coil and the second detecting receiving coil when an alternating current is applied, and the transmitting coil is formed so as to collectively surround at least a portion of the plurality of first detecting receiving coils and the plurality of second detecting receiving coils.

[0138] [Sixth Aspect] The position detection device according to the fifth aspect, wherein the transmitter coil is formed so as to surround all of the plurality of first detector receiver coils and the plurality of second detector receiver coils.

[0139] [Seventh Aspect] A position detection device according to any one of the fourth to sixth aspects, wherein the transmitting coil is in the shape of an arc frame with the longitudinal direction being the circumferential direction of the substrate, and the first detecting receiving coil and the second detecting receiving coil are formed at positions that are 5° or more away from an imaginary line (K20, K21) that passes through the circumferential end of the transmitting coil and extends in a direction perpendicular to the rotation axis.

[0140] [Eighth Aspect] The position detection device according to the seventh aspect, wherein the first detection receiver coil and the second detection receiver coil are formed at positions spaced apart from the imaginary line by 10° or more in the circumferential direction.

[0141] [Ninth Aspect] A position detection device according to any one of the fourth to eighth aspects, wherein the transmitting coil is in the shape of an arc frame with the longitudinal direction being the circumferential direction of the substrate, and a circuit board (100) having the signal processing unit is arranged on the substrate in an area surrounded by the transmitting coil.

[0142] [Tenth Aspect] A position detection device according to any one of the first to ninth aspects, wherein the substrate has an arc portion along the circumferential direction, and an opening is formed therein, so that the substrate has one end (31) on one side of the circumferential direction and the other end (32) on the other side of the circumferential direction.

[0143] [Eleventh Aspect] A position detection device according to any one of the first to eighth and tenth aspects, wherein the substrate has a detection area (33) formed by the arc portion along the circumferential direction and a mounting area (34) protruding from the outer edge of the arc portion, the first detection receiver coil and the second detection receiver coil are formed in the detection area, and a circuit board (100) having the signal processing unit is arranged in the mounting area.

Claims

1. A position detection device comprising: a rotating member (20) that rotates around a rotation axis (CL) of a shaft member (70); a substrate (30) that is shaped to have an arc portion along a circumferential direction (Dc) of the rotation axis and that is disposed opposite the rotating member; first detection receiving coils (51-53) that are formed on the substrate and generate a first signal (V1) having periodicity corresponding to a change in a magnetic field accompanying the rotation of the rotating member; second detection receiving coils (61-63) that are formed on the substrate and generate a second signal (V2) having a periodicity corresponding to a change in a magnetic field accompanying the rotation of the rotating member and having a phase different from that of the first signal; and a signal processing unit (110) that detects a rotation angle of the rotating member; wherein a plurality of three or more first detection receiving coils are provided along the circumferential direction of the substrate and are connected in series; and a plurality of three or more second detection receiving coils are provided along the circumferential direction of the substrate and are connected in series; The signal processing unit receives a first detection signal value (AV1) obtained by adding together the first signals generated in the multiple first detection receiving coils, and a second detection signal value (AV2) obtained by adding together the second signals generated in the multiple second detection receiving coils, and detects the angle of the rotating member based on the first detection signal value and the second detection signal value.

2. A position detection device as described in claim 1, wherein the first detection receiving coil is formed as a closed-loop sine wave in a normal direction to the surface direction of the substrate, and the second detection receiving coil is formed as a cosine wave in the normal direction.

3. A position detection device as described in claim 1, wherein the first detection receiver coil is spirally shaped in a normal direction to the surface direction of the substrate, and the second detection receiver coil is spirally shaped in the normal direction.

4. A position detection device as described in claim 1, comprising transmitting coils (40a to 40c) that generate a magnetic field that passes through the first detection receiving coil and the second detection receiving coil when an alternating current is applied, and the transmitting coils are formed in plurality so as to surround one of the first detection receiving coil and one of the second detection receiving coils.

5. A position detection device as described in claim 1, further comprising a transmitting coil (40) that generates a magnetic field passing through the first detection receiving coil and the second detection receiving coil when an alternating current is applied thereto, the transmitting coil being formed so as to collectively surround at least a portion of the plurality of first detection receiving coils and the plurality of second detection receiving coils.

6. A position detection device according to claim 5, wherein the transmitting coil is formed so as to collectively surround all of the plurality of first detecting receiving coils and all of the plurality of second detecting receiving coils.

7. A position detection device as described in any one of claims 4 to 6, wherein the transmitting coil is in the shape of an arc frame with its longitudinal direction being the circumferential direction of the substrate, and the first detecting receiving coil and the second detecting receiving coil are formed at a position 5° or more away in the circumferential direction from an imaginary line (K20, K21) that passes through the circumferential end of the transmitting coil and extends in a direction perpendicular to the rotation axis.

8. A position detection device according to claim 7, wherein the first detection receiving coil and the second detection receiving coil are formed at a position spaced apart from the imaginary line by 10° or more in the circumferential direction.

9. A position detection device as described in any one of claims 4 to 6, wherein the transmitting coil is in the shape of an arc frame with its longitudinal direction aligned with the circumferential direction of the substrate, and a circuit board (100) having the signal processing unit is disposed on the substrate in an area surrounded by the transmitting coil.

10. A position detection device as described in claim 1, wherein the substrate has an arc portion along the circumferential direction, and an opening is formed so that the substrate has one end (31) on one side in the circumferential direction and the other end (32) on the other side in the circumferential direction.

11. A position detection device as described in claim 1, wherein the substrate has a detection area (33) consisting of the arc portion along the circumferential direction, and a mounting area (34) protruding from the outer edge of the arc portion, the first detection receiving coil and the second detection receiving coil are formed in the detection area, and a circuit board (100) having the signal processing unit is disposed in the mounting area.

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