Encoders and control systems

Abstract

An encoder (10) is provided with: an emitting unit (40) that emits light; a rotating plate (20) which rotates and which includes an annular region (26) that is provided so as to surround a rotational axis (A) of the rotating plate (20) and that reflects or transmits light emitted from the emitting unit (40); a light receiving unit (50) that receives light that has been emitted from the emitting unit (40) and that has passed through the annular region (26); a signal processing circuit (61) that processes a signal from the light receiving unit (50); and a determining circuit (62) that determines an abnormality on the basis of an output result processed by the signal processing circuit (61). Further, the light receiving unit (50) includes: a first set having a first light receiving region (55) and a second light receiving region (56) arranged in a first direction intersecting a direction of rotation (C) of the rotating plate (20); and a second set having a third light receiving region (57) and a fourth light receiving region (58) arranged in a second direction intersecting the direction of rotation (C), and provided side-by-side with the first set in the direction of rotation (C).

Description

[Technical Field]

[0001] This disclosure relates to encoders and control systems. [Background technology]

[0002] Conventionally, encoders that detect the rotation of an object to be detected, such as a motor shaft, are known. For example, Patent Document 1 discloses a vibration analysis and diagnostic system comprising a plurality of vibration sensors that detect vibrations in multiple parts of a machine, and an information terminal device that switches between the plurality of vibration sensors individually to diagnose abnormalities in the machine. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-071040 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, in the vibration analysis and diagnostic system described in Patent Document 1, when diagnosing abnormalities in the rotating shaft mounted on a motor or the like, additional equipment such as an information terminal device for diagnosing abnormalities is required, which presents a challenge in that the configuration becomes complicated.

[0005] This disclosure was made to solve these problems and aims to provide an encoder and control system that can diagnose abnormalities with a simple configuration. [Means for solving the problem]

[0006] An encoder according to one aspect of the present disclosure includes: an emission unit that emits light; a rotating plate that rotates, the rotating plate being provided so as to surround the rotation axis of the rotating plate and having an annular region that reflects or transmits light emitted from the emission unit; a light receiving unit that receives light emitted from the emission unit and that has passed through the annular region; a signal processing circuit that processes the signal from the light receiving unit; and a determination circuit that determines an abnormality based on the output result processed by the signal processing circuit, wherein the light receiving unit has a first set having a first light receiving region and a second light receiving region arranged in a first direction intersecting the rotation direction of the rotating plate, and a second set having a third light receiving region and a fourth light receiving region arranged in a second direction intersecting the rotation direction and provided alongside the first set in the rotation direction.

[0007] Furthermore, a control system according to one aspect of the present disclosure includes an encoder and a display unit that displays an abnormality when the DC component of the signal indicating the value of X and the DC component of the signal indicating the value of Y exceed the first threshold, wherein the predetermined threshold includes a first threshold. [Effects of the Invention]

[0008] According to this disclosure, an encoder or the like that can diagnose abnormalities with a simple configuration can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a block diagram showing a control system according to the first embodiment. [Figure 2] Figure 2 is a perspective view showing an encoder according to the first embodiment. [Figure 3] Figure 3 is a schematic diagram of the rotating plate of the encoder shown in Figure 2, viewed from the axial direction. [Figure 4] Figure 4 is a schematic diagram of the light-emitting and light-receiving sections of the encoder shown in Figure 2, viewed from the axial direction. [Figure 5] Figure 5 is an explanatory diagram illustrating the relationship between the dimensions of the first and second light-receiving regions and the dimensions of the light irradiated onto the first and second light-receiving regions in the encoder shown in Figure 2. [Figure 6] FIG. 6 is a block diagram showing the functional configuration of the encoder of FIG. 2. [Figure 7A] FIG. 7A is a diagram showing the state of inclination of the rotation axis of the motor and the X signal intensity and Y signal intensity corresponding to the state of inclination of the rotation axis of the motor. [Figure 7B] FIG. 7B is a diagram showing the rotation axis of the motor inclined obliquely and the X signal intensity and Y signal intensity at that time. [Figure 8] FIG. 8 is a block diagram showing the functional configuration of the encoder according to the second embodiment. [Figure 9] FIG. 9 is a schematic diagram showing an example of a state in which the axis of the annular region is eccentric with respect to the rotation axis. [Figure 10] FIG. 10 is a schematic diagram showing an example of a change in the position of the light irradiated to the first light receiving region, the second light receiving region, the third light receiving region, and the fourth light receiving region as the rotating plate rotates in a state where the axis of the annular region is eccentric with respect to the rotation axis. [Figure 11] FIG. 11 is a graph showing an example of a signal output by an output unit as the rotating plate rotates in a state where the axis of the annular region is eccentric with respect to the rotation axis. [Figure 12A] FIG. 12A is a flowchart showing an example of a calculation method by the calculation unit of the encoder of FIG. 2. [Figure 12B] FIG. 12B is a flowchart showing another example of a calculation method by the calculation unit of the encoder of FIG. 2. [Figure 13A] FIG. 13A is a diagram showing the noise included in the Y signal and the Y signal after fitting. [Figure 13B] FIG. 13B is a flowchart showing an example of a method for angle correction. [Figure 13C] FIG. 13C is a flowchart showing another example of a method for angle correction. [Figure 13D] FIG. 13D is a flowchart showing an example of a method for determining the presence or absence of an abnormality using a constant term γ. [Figure 14]FIG. 14 is a schematic view of the rotating plate of the encoder according to the third embodiment as viewed in the axial direction. [Figure 15] FIG. 15 is a schematic view of the light emitting portion and the light receiving portion of the encoder of FIG. 14 as viewed in the axial direction. [Figure 16] FIG. 16 is a schematic view of the rotating plate of the encoder according to the fourth embodiment as viewed in the axial direction. [Figure 17] FIG. 17 is a schematic view of the light emitting portion and the light receiving portion of the encoder of FIG. 16 as viewed in the axial direction. [Figure 18] FIG. 18 is a schematic view of the light emitting portion and the light receiving portion of the encoder according to the fifth embodiment as viewed in the axial direction. [Figure 19] FIG. 19 is an explanatory diagram for explaining the relationship between the dimensions of the first light receiving region and the second light receiving region and the dimensions of the light irradiated to the first light receiving region and the second light receiving region in the encoder according to the sixth embodiment.

Embodiments for Carrying out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described. Note that each of the embodiments described below shows a specific example of the present disclosure. Therefore, the numerical values, components, arrangement positions and connection forms of the components, and the processes and the order of the processes shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, the components not described in the independent claims are described as optional components.

[0011] Also, each figure is a schematic view and is not necessarily drawn precisely. In each figure, the same reference numerals are given to substantially the same configurations, and duplicate explanations are omitted or simplified.

[0012] Furthermore, in the following embodiments, expressions indicating the relative orientation of two directions, such as parallel and orthogonal, may be used, but these expressions include cases where the orientation is not strictly accurate. For example, when two directions are orthogonal, unless otherwise specified, this means not only that the two directions are perfectly orthogonal, but also that they are substantially orthogonal, that is, that they include a difference of, for example, a few percent.

[0013] Furthermore, in the following embodiments, expressions such as "plate-like" and "axial direction" are used. For example, "plate-like" and "axial direction" mean not only that it is completely plate-like and axial, but also that it is substantially plate-like and axial, i.e., that it includes an error of a few percent. Also, "plate-like" and "axial direction" means plate-like and axial direction to the extent that the effects of this disclosure can be achieved. The same applies to other expressions using "like" and "direction".

[0014] (First Embodiment) First, the functional configuration of the control system 3 according to the first embodiment will be explained using Figures 1 to 5.

[0015] Figure 1 is a block diagram of a control system 3 according to the first embodiment. Figure 2 is a perspective view showing an encoder 10 according to the embodiment. Figure 3 is a schematic diagram of the rotating plate 20 of the encoder 10 in Figure 2 as viewed from the axial direction. Figure 4 is a schematic diagram of the light emission section 40 and light receiving section 50 of the encoder 10 in Figure 2 as viewed from the axial direction. Figure 5 is an explanatory diagram for illustrating the relationship between the dimensions of the first light receiving area 55 and the second light receiving area 56 and the dimensions of the light irradiated onto the first light receiving area 55 and the second light receiving area 56 in the encoder 10 of Figure 2.

[0016] In Figure 2, to avoid making the drawing too complex, the first absolute pattern 22, the second absolute pattern 23, the first incremental pattern 24, and the second incremental pattern 25 are omitted from the illustration. Also, in Figure 3, to avoid making the drawing too complex, only half of the rotating plate 20 is shown. Furthermore, in Figure 5, to avoid making the drawing too complex, the emission section 40 and the first and second light-receiving regions 55 and 56 are shown shifted in the first direction E. The axial direction refers to the direction in which the rotation axis A extends (the Z-axis direction in Figure 2, etc.).

[0017] As shown in Figure 1, the control system 3 can detect the motor's condition and predict motor failure by using an encoder. The control system 3 includes an encoder 10 and a display unit 80.

[0018] Next, we will describe the configuration of encoder 10.

[0019] As shown in Figure 2, the encoder 10 detects the rotation of the object to be detected. Specifically, the encoder 10 detects the position (rotational position), rotational direction, amount of rotation, and / or number of rotations of the object to be detected. The object to be detected rotates around the rotation axis A as the center of rotation. In this embodiment, the object to be detected is the rotation axis (shaft) of the motor 1.

[0020] The encoder 10 comprises a rotating plate 20, a substrate 30, an emission unit 40, and a light receiving unit 50.

[0021] As shown in Figures 2 and 3, the rotating plate 20 rotates with the motor 1 around the rotation axis A as the center of rotation. The rotating plate 20 has a body 21, a first absolute pattern 22, a second absolute pattern 23, a first incremental pattern 24, a second incremental pattern 25, and an annular region 26. The first absolute pattern 22, the second absolute pattern 23, the first incremental pattern 24, and the second incremental pattern 25 are examples of one or more patterns for detecting the rotation angle of the rotating plate 20 (motor 1).

[0022] The main body 21 is plate-shaped with its axial direction as the thickness direction, and is circular when viewed from the axial direction. The main body 21 is attached to one end of the motor 1 in the axial direction and rotates together with the motor 1 about the rotation axis A as the center of rotation. The axis of the main body 21 coincides with the axis B of the annular region 26.

[0023] The first absolute pattern 22 is a pattern for detecting the absolute position of the motor 1. The first absolute pattern 22 is provided on the main surface of the main body 21 on the side of the emission section 40, and is provided in an annular shape so as to surround the rotation axis A. The axis of the first absolute pattern 22 coincides with the axis B of the annular region 26. For example, the first absolute pattern 22 is composed of a reflective section that reflects the light emitted from the emission section 40 toward the light receiving section 50 and a non-reflective section that does not reflect the light emitted from the emission section 40 toward the light receiving section 50, arranged in an annular shape.

[0024] The second absolute pattern 23 is a pattern for detecting the absolute position of the motor 1. The second absolute pattern 23 is provided on the main surface of the main body 21 on the side of the emission section 40, and is provided in an annular shape so as to surround the rotation axis A. The axis of the second absolute pattern 23 coincides with the axis B of the annular region 26. The second absolute pattern 23 is provided further inward than the first absolute pattern 22 in the radial direction centered on the axis B of the annular region 26. For example, the second absolute pattern 23 is composed of a reflective section that reflects the light emitted from the emission section 40 toward the light receiving section 50 and a non-reflective section that does not reflect the light emitted from the emission section 40 toward the light receiving section 50, arranged in an annular shape.

[0025] The first incremental pattern 24 is a pattern for detecting the relative position of the motor 1. The first incremental pattern 24 is provided on the main surface of the main body 21 on the side of the emission section 40, and is provided in an annular shape so as to surround the rotation axis A. The axis of the first incremental pattern 24 coincides with the axis B of the annular region 26. In the radial direction centered on the axis B of the annular region 26, the first incremental pattern 24 is provided further out than the first absolute pattern 22. For example, the first incremental pattern 24 is composed of a reflective section that reflects the light emitted from the emission section 40 toward the light receiving section 50 and a non-reflective section that does not reflect the light emitted from the emission section 40 toward the light receiving section 50, arranged in an annular shape.

[0026] The second incremental pattern 25 is a pattern for detecting the relative position of the motor 1. The second incremental pattern 25 is provided on the main surface of the main body 21 on the side of the emission section 40, and is provided in an annular shape so as to surround the rotation axis A. The axis of the second incremental pattern 25 coincides with the axis B of the annular region 26. The second incremental pattern 25 is provided further inward than the second absolute pattern 23 in the radial direction centered on the axis B of the annular region 26. For example, the second incremental pattern 25 is composed of a reflective section that reflects the light emitted from the emission section 40 toward the light receiving section 50 and a non-reflective section that does not reflect the light emitted from the emission section 40 toward the light receiving section 50, arranged in an annular shape.

[0027] For example, each of the one or more patterns used to detect the rotation angle of the rotating plate 20 may transmit light emitted from the emission unit 40.

[0028] The annular region 26 is an annular region provided so as to surround the axis of rotation A and reflects the light emitted from the emission section 40. The annular region 26 reflects the light emitted from the emission section 40 toward the light receiving section 50. The annular region 26 is provided on the main surface of the main body 21 on the side of the emission section 40. The direction in which the axis B of the annular region 26 extends coincides with the axial direction. Figure 2 illustrates the state in which the axis B of the annular region 26 coincides with the axis of rotation A. For example, the annular region 26 is composed of continuously arranged annular reflective sections that reflect the light emitted from the emission section 40 toward the light receiving section 50.

[0029] As shown in Figure 2, the substrate 30 is positioned opposite the rotating plate 20 in the axial direction. The substrate 30 is plate-shaped with the axial direction being the thickness direction.

[0030] As shown in Figures 2 and 4, the emission unit 40 emits light. Specifically, the emission unit 40 emits light toward the rotating plate 20. More specifically, the emission unit 40 emits light toward the first absolute pattern 22, the second absolute pattern 23, the first incremental pattern 24, the second incremental pattern 25, and the annular region 26. The emission unit 40 is provided on the main surface of the substrate 30 on the rotating plate 20 side.

[0031] The light-receiving unit 50 receives light that has been emitted from the emission unit 40 and passed through the annular region 26. The light-receiving unit 50 has a first absolute light-receiving region 51, a second absolute light-receiving region 52, a first incremental light-receiving region 53, a second incremental light-receiving region 54, a first set, and a second set. The first absolute light-receiving region 51, the second absolute light-receiving region 52, the first incremental light-receiving region 53, and the second incremental light-receiving region 54 are examples of one or more light-receiving regions that receive light that has been emitted from the emission unit 40 and passed through one or more patterns.

[0032] The first absolute light-receiving region 51 receives light emitted from the emission section 40 and that has passed through the first absolute pattern 22.

[0033] The second absolute light-receiving region 52 receives light emitted from the emission section 40 and that has passed through the second absolute pattern 23.

[0034] The first incremental light-receiving region 53 receives light emitted from the emission section 40 and that has passed through the first incremental pattern 24.

[0035] The second incremental light-receiving region 54 receives light emitted from the emission section 40 and that has passed through the second incremental pattern 25.

[0036] The first set has a first light-receiving region 55 and a second light-receiving region 56 aligned in a first direction E that intersects with the rotation direction C of the rotating plate 20. The second set has a third light-receiving region 57 and a fourth light-receiving region 58 aligned in a second direction F that intersects with the rotation direction C, and is provided alongside the first set in the rotation direction C. In other words, the third light-receiving region 57 and the fourth light-receiving region 58 are provided alongside the first light-receiving region 55 and the second light-receiving region 56 in the rotation direction C.

[0037] In this embodiment, the first set and the second set are arranged with the emission unit 40 in the rotation direction C. That is, the first light-receiving area 55 and the second light-receiving area 56, and the third light-receiving area 57 and the fourth light-receiving area 58 are arranged with the emission unit 40 in the rotation direction C.

[0038] The first direction E and the second direction F are directions parallel to a plane perpendicular to the rotation axis A. In this embodiment, the first direction E and the second direction F are directions parallel to a straight line G perpendicular to the rotation axis A (Y-axis direction), and the first set and the second set are arranged symmetrically with respect to the straight line G as the axis of symmetry. That is, the first light-receiving region 55 and the second light-receiving region 56 are aligned in a direction parallel to the straight line G, the third light-receiving region 57 and the fourth light-receiving region 58 are aligned in a direction parallel to the straight line G, and the first light-receiving region 55 and the second light-receiving region 56 and the third light-receiving region 57 and the fourth light-receiving region 58 are arranged symmetrically with respect to the straight line G as the axis of symmetry.

[0039] In the radial direction centered on the rotation axis A, the first light-receiving region 55 and the third light-receiving region 57 are located at the same position, and the second light-receiving region 56 and the fourth light-receiving region 58 are located at the same position.

[0040] The first light-receiving region 55 and the second light-receiving region 56 are each positioned to receive light emitted from the emission section 40 and passing through the annular region 26 (see H in Figure 4). The third light-receiving region 57 and the fourth light-receiving region 58 are each positioned to receive light emitted from the emission section 40 and passing through the annular region 26 (see H in Figure 4).

[0041] For example, the first light-receiving region 55, the second light-receiving region 56, the third light-receiving region 57, and the fourth light-receiving region 58 are each light-receiving regions in a light-receiving element. In other words, for example, the light-receiving unit 50 is composed of multiple light-receiving elements.

[0042] As shown in Figure 5, in this embodiment, the emission unit 40 has a point light source, and the dimension between the annular region 26 and the emission unit 40 in the axial direction is h1, the dimension between the annular region 26 and the first light-receiving region 55 and the second light-receiving region 56 in the axial direction is h2, the dimension from the end of the first light-receiving region 55 opposite to the second light-receiving region 56 in the first direction E is L, the dimension of the annular region 26 in the first direction E is W1, and the dimension in the first direction E of the light emitted from the point light source and irradiated onto the first light-receiving region 55 and the second light-receiving region 56 via the annular region 26 is W2, then W2 = (h2 / h1) × W1 and W2 / L < 1 are satisfied. The same relationship is also satisfied for the third light-receiving region 57 and the fourth light-receiving region 58.

[0043] The dimension L from the end of the first light-receiving region 55 opposite to the second light-receiving region 56 in the first direction E is greater than the dimension W2 in the first direction E of the light emitted from the emission unit 40 and irradiated onto the first light-receiving region 55 and the second light-receiving region 56 via the annular region 26. Also, the dimension from the end of the third light-receiving region 57 opposite to the fourth light-receiving region 58 in the second direction F is greater than the dimension in the second direction F of the light emitted from the emission unit 40 and irradiated onto the third light-receiving region 57 and the fourth light-receiving region 58 via the annular region 26.

[0044] The configuration of encoder 10 has been described above.

[0045] Next, the functional configuration of the encoder 10 will be explained using Figure 6.

[0046] Figure 6 is a block diagram showing the functional configuration of the encoder 10 in Figure 2.

[0047] As shown in Figure 6, the encoder 10 further includes a signal processing circuit 61 and a determination circuit 62.

[0048] The signal processing circuit 61 processes the signals from the light receiving unit 50. In other words, the signal processing circuit 61 processes signals corresponding to the light received by the light receiving unit 50. Specifically, the signal processing circuit 61 processes signals corresponding to the light received in the first absolute light receiving area 51, the second absolute light receiving area 52, the first incremental light receiving area 53, the second incremental light receiving area 54, the first light receiving area 55, the second light receiving area 56, the third light receiving area 57, and the fourth light receiving area 58. For example, a signal corresponding to light reception is a signal corresponding to the intensity of light. The signal processing circuit 61 outputs the result of processing the signals to the determination circuit 62.

[0049] The determination circuit 62 determines an abnormality based on the output result processed by the signal processing circuit 61. When determining whether there is an abnormality in the rotating shaft, the determination includes cases where there is an error in the position signal of the encoder 10. Specifically, when the signal value corresponding to the reception of light in the first light receiving area 55 is A1, the signal value corresponding to the reception of light in the second light receiving area 56 is A2, the signal value corresponding to the reception of light in the third light receiving area 57 is B1, and the signal value corresponding to the reception of light in the fourth light receiving area 58 is B2, the signal processing circuit 61 processes the following signals indicating the value of X (sometimes called the X signal) and the signal indicating the value of Y (sometimes called the Y signal), and the determination circuit 62 monitors whether the changes in the DC component of the X signal and the DC component of the Y signal exceed a predetermined threshold. In this case, the values ​​X and Y satisfy the following relationship.

[0050] X = (A1 + B2) - (B1 + A2) Y=(A1+B1)-(A2+B2)

[0051] The X value indicates the direction and amount of tilt of the rotation axis, based on the difference between the sum of the signal values ​​of the first light-receiving area 55 and the fourth light-receiving area 58 (A1+B2) and the sum of the signal values ​​of the second light-receiving area 56 and the third light-receiving area 57 (B1+A2). The Y value indicates the amount of eccentricity of the center of the rotating plate, as well as the direction and amount of tilt of the rotation axis, based on the difference between the sum of the signal values ​​of the first light-receiving area 55 and the third light-receiving area 57 located on the outer diameter side (A1+B1) and the sum of the signal values ​​of the second light-receiving area 56 and the fourth light-receiving area 58 located on the inner diameter side (A2+B2).

[0052] Here, the predetermined threshold includes a first threshold, a second threshold, and a third threshold.

[0053] The first threshold is used when the total operating time of the motor 1 shown in Figure 1, mounted on the encoder 10, is longer than the first set time. The second threshold is used when the total operating time of the motor is less than or equal to the first set time. The third threshold is used when the total operating time of the motor exceeds the second set time, which is longer than the first set time. Therefore, the first, second, and third thresholds are all different. The first set time is a time when the bearing wear of the motor 1 is considered to be extremely low, for example, 100 hours or less. The second set time is a time when the bearing wear of the motor 1 is considered to be likely to occur, for example, exceeding 1000 hours.

[0054] First, the setting of the first threshold will be explained using Figure 7A.

[0055] Figure 7A shows the tilt of the rotation axis of motor 1 and the corresponding X and Y signal strengths. Figure 7A(a1) shows the rotation axis of motor 1 with no axial misalignment. The rotation axis of motor 1 with no axial misalignment is the rotation axis of motor 1 that is not eccentric. Figure 7A(a2) shows the X and Y signal strengths when there is no axial misalignment on the axis of the rotation axis of motor 1. Figure 7A(b1) shows the rotation axis of motor 1 with axial misalignment in the X direction. Figure 7A(b2) shows the X signal strength when axial misalignment occurs on the axis of the rotation axis of motor 1. Figure 7A(c1) shows the rotation axis of motor 1 with axial misalignment in the Y direction. Figure 7A(c2) shows the Y signal strength when axial misalignment occurs on the axis of the rotation axis of motor 1. Note that in Figure 7A (a1), the motor 1 and the center of the rotating plate are shown to be aligned. However, if the center of the rotating plate and the axis of rotation of the motor 1 are misaligned (eccentricity exists), and there is no angular displacement in the rotation axis of the motor 1, the phase characteristics will be as shown in Figure 7A (a2). For example, in the case of the second light-receiving region 56, even if eccentricity of a few μm, which is smaller than the size of the second light-receiving region 56, occurs, it will appear as a phase characteristic as shown in Figure 7A (a2). Therefore, in Figure 7A (a1), it should be assumed that eccentricity of a degree that cannot be represented is occurring.

[0056] As shown in Figure 7A (a2), there is a 90° phase difference between the X signal and the Y signal, and the amplitudes of the X signal and the Y signal have different relationships.

[0057] As shown in Figures 7A (a1) and (a2), if there is no deviation in the axis of rotation of motor 1, which coincides with the rotation axis A, then there is no DC offset in the X and Y signals.

[0058] However, as shown in Figures 7A (b1) and (b2), when the rotation axis of motor 1 is tilted in the positive X-axis direction (when a deflection occurs in the rotation axis in the positive X-axis direction), there is no DC offset in the Y signal, but a DC offset is added to the X signal. The DC offset added to the X signal is shown by the distance from the axis indicating the eccentric phase passing through the X and Y signal strength 0 to the dashed line. As a result, the X signal in Figure 7A (b2) is shifted to the positive side of the X signal strength.

[0059] Furthermore, as shown in (c1) and (c2) of Figure 7A, when the rotation axis of motor 1 is tilted in the positive Y-axis direction (when a deflection in the positive Y-axis direction occurs on the rotation axis), no DC offset is added to the X signal, but a DC offset is added to the Y signal. The DC offset of the Y signal is shown by the distance from the axis indicating the eccentric phase passing through the X and Y signal strengths of 0 to the dashed line. As a result, the Y signal in (c2) of Figure 7A shifts to the positive side of the Y signal strength. At this time, the DC offset when the rotation axis of motor 1 is tilted in the positive X-axis direction is not equal to the DC offset when the rotation axis of motor 1 is tilted in the positive Y-axis direction. For this reason, different first thresholds are set for the DC components of the X signal and the Y signal, respectively. The first threshold for the DC component of the X signal is called the first X signal threshold, and the first threshold for the DC component of the Y signal is called the first Y signal threshold.

[0060] Next, we will explain how to set the second threshold.

[0061] As described above, the DC offset when the rotation axis of motor 1 is tilted in the positive X-axis direction is not equal to the DC offset when the rotation axis of motor 1 is tilted in the positive Y-axis direction. For this reason, different second thresholds are set for the DC components of the X signal and the Y signal, respectively. The second threshold for the DC component of the X signal is called the second X signal threshold, and the second threshold for the DC component of the Y signal is called the second Y signal threshold.

[0062] Next, we will explain how to set the third threshold.

[0063] As described above, the DC offset when the rotation axis of motor 1 is tilted in the positive X-axis direction is not equal to the DC offset when the rotation axis of motor 1 is tilted in the positive Y-axis direction. For this reason, different third thresholds are set for the DC components of the X signal and the Y signal, respectively. The third threshold for the DC component of the X signal is called the third X signal threshold, and the third threshold for the DC component of the Y signal is called the third Y signal threshold.

[0064] The above explains how to set the first, second, and third thresholds.

[0065] Now, let's return to the explanation of the judgment circuit 62.

[0066] As shown in Figures 1 and 6, (1) the determination circuit 62 determines whether the time is less than or equal to the first set time and monitors whether the changes in the DC components of the X signal and the Y signal exceed a predetermined threshold. Also, (2) the determination circuit 62 determines whether the time has exceeded the second set time and monitors whether the changes in the DC components of the X signal and the Y signal exceed a predetermined threshold.

[0067] Regarding (1), the determination circuit 62 determines whether or not the time is less than or equal to the first set time. Since the second threshold is used when the total motor operating time is short, the determination circuit 62 can determine that a large load is being applied to the rotation shaft of motor 1 and that an angle deviation is occurring in the axis of the rotation shaft when the DC component of the X signal or the DC component of the Y signal exceeds the second threshold. Therefore, the determination circuit 62 sequentially acquires the total motor operating time from motor 1 or the motor control unit, etc., and determines whether or not the time is less than or equal to the first set time based on the acquired total motor operating time.

[0068] If the determination circuit 62 determines that the time is less than or equal to the first set time, it determines whether the DC component of the X signal exceeds the second X signal threshold, or whether the DC component of the Y signal exceeds the second Y signal threshold.

[0069] The determination circuit 62 determines that the total operating time of the motor mounted on the encoder 10 is less than or equal to the first set time, and that the DC component of the X signal or the DC component of the Y signal exceeds the second threshold, and outputs the determination result to the display unit 80. The display unit 80 displays the determination result. Specifically, the display unit 80 displays that the DC component of the X signal exceeded the second X signal threshold despite the total motor operating time being less than or equal to the first set time, or that the DC component of the Y signal exceeded the second Y signal threshold despite the total motor operating time being less than or equal to the first set time. In other words, the display unit 80 indicates that there is excessive rotational shaft load when the total motor operating time is less than or equal to the first set time and the DC component of the X signal or the DC component of the Y signal exceeds the second threshold.

[0070] Regarding (2), if the determination circuit 62 determines that the first set time has been exceeded, the determination circuit 62 determines whether the second set time has been exceeded. Since the third threshold is used when the total motor operating time is long, the determination circuit 62 can determine that a large load is being applied to the rotation shaft of motor 1 and that an angle deviation is occurring in the axis of the rotation shaft when the DC component of the X signal or the DC component of the Y signal exceeds the third threshold. Therefore, the determination circuit 62 sequentially acquires the total motor operating time from motor 1 or the motor control unit, etc., and determines whether the second set time has been exceeded based on the acquired total motor operating time.

[0071] If the determination circuit 62 determines that the time is less than or equal to the second set time, that is, if it determines that the time is greater than the first set time and less than or equal to the second set time, it determines whether the DC component of the X signal exceeds the first X signal threshold, or whether the DC component of the Y signal exceeds the first Y signal threshold.

[0072] The determination circuit 62 determines that the total operating time of the motor mounted on the encoder 10 is less than or equal to the second set time, and that the DC component of the X signal or the DC component of the Y signal exceeds the first threshold, and outputs the determination result to the display unit 80. The display unit 80 displays the determination result. Specifically, the display unit 80 displays that the DC component of the X signal has exceeded the first X signal threshold, or that the DC component of the Y signal has exceeded the first Y signal threshold. In other words, the display unit 80 indicates that there is a problem with the motor 1 when the total operating time of the motor exceeds the first set time but is less than or equal to the second set time, and the DC component of the X signal or the DC component of the Y signal exceeds the first threshold.

[0073] Furthermore, if the determination circuit 62 determines that the second set time has been exceeded, it determines whether the DC component of the X signal has exceeded the third X signal threshold, or whether the DC component of the Y signal has exceeded the third Y signal threshold.

[0074] The determination circuit 62 determines that the total operating time of the motor mounted on the encoder 10 exceeds the second set time, and that the DC component of the X signal or the DC component of the Y signal exceeds the third threshold, and outputs the determination result to the display unit 80. The display unit 80 displays the determination result. Specifically, the display unit 80 displays that the DC component of the X signal has exceeded the third X signal threshold, or that the DC component of the Y signal has exceeded the third Y signal threshold. In other words, the display unit 80 indicates that there is a bearing failure in the motor 1 when the total operating time of the motor exceeds the second set time and the DC component of the X signal or the DC component of the Y signal exceeds the third threshold.

[0075] The functional configuration of encoder 10 has been explained above.

[0076] Next, the functional configuration of the control system 3 will be described.

[0077] The control system 3 includes an operating mode for normal operation of the motor 1.

[0078] Furthermore, in the control system 3, the determination circuit 62 rotates the motor 1's rotation axis by one or more revolutions in order to determine whether or not there is an abnormality based on the output of the signal processing circuit 61. In other words, the control system 3 has a dedicated operating mode that rotates the motor 1 by one or more revolutions in order to determine whether or not there is an abnormality. In order for the determination circuit 62 to determine whether or not there is an abnormality based on the output of the signal processing circuit 61, the control system 3 rotates the motor 1's rotation axis by one or more revolutions in a dedicated operating mode. Specifically, when the determination circuit 62 determines whether or not there is an abnormality in the motor 1, the motor control unit of the control system 3 rotates the motor 1's rotation axis by one or more revolutions based on the dedicated operating mode. The dedicated operating mode may also be executed in response to a request from the determination circuit 62. Such a dedicated operating mode can be realized by a control unit such as a processor or microcomputer provided in the control system 3.

[0079] This dedicated operating mode is not a normal operating mode in which the control system 3 operates the motor 1, but rather a mode that can be executed when the control system 3 is in a maintenance mode or similar, and it is a mode that allows for the measurement of the phase characteristics of the DC offset.

[0080] Furthermore, the control system 3 has a function to determine the amount and direction of the tilt of the motor 1's rotation axis from the sign (positive or negative) and absolute value of the DC offset of the X signal and Y signal obtained by rotating the motor 1's rotation axis once. In other words, the rotation axis of the motor 1 may be tilted in both the X-axis direction and the Y-axis direction. Figure 7B illustrates the case where the rotation axis of the motor 1 is tilted in both the positive X-axis direction and the positive Y-axis direction. Figure 7B shows the rotation axis of the motor 1 tilted at an angle, and the X signal intensity and Y signal intensity at that time. Figure 7B(a1) shows the rotation axis of the motor 1 with an angle deviation in both the X-axis direction and the Y-axis direction. Figure 7B(a2) shows the X signal intensity when an angle deviation occurs around the axis of the motor 1's rotation axis. Figure 7B(a3) shows the Y signal intensity when an angle deviation occurs around the axis of the motor 1's rotation axis. As shown in Figure 7B(a1), when the rotation axis of motor 1 is tilted in both the X-axis and Y-axis directions, the control system 3 measures the phase characteristics of the DC offsets of the X signal and Y signal, respectively, as shown in Figures 7B(a2) and 7B(a3). This function of determining the amount and direction of the tilt of the rotation axis of motor 1 can be realized by a control unit such as a processor or microcomputer in the control system 3. The amount of tilt is, for example, the angle of deviation of the axis of rotation.

[0081] Furthermore, the control system 3 has a function to determine the amount of tilt of the axis of rotation from the sign and absolute value of the DC offset of the X signal obtained by rotating the rotation axis of the motor 1 once, and to correct the angular error caused by the amount of tilt of the axis of rotation. Specifically, the control system 3 calculates the angle of deviation occurring at the axis of rotation as the amount of tilt of the axis of rotation, calculates an angular error value based on the calculated angle of deviation, and performs angular correction based on the calculated angular error value.

[0082] For example, if the rotation axis of motor 1 is tilted in the positive X-axis direction, an angular error occurs. In this case, the control system 3 calculates the amount of tilt of the rotation axis and the angular error value caused by the amount of tilt of the axis in the positive X-axis direction. The control system 3 performs angular correction based on the calculated amount of tilt and angular error value. For example, in the case of (b2) in Figure 7A, if the axis is tilted in the positive X-axis direction, the control system 3 calculates the angular error value of the DC offset and corrects it by subtracting the DC offset from the X signal, as shown in the Y signal in (a2) in Figure 7A.

[0083] Furthermore, if the rotation axis of motor 1 is tilted in the positive Y-axis direction, angular errors are less likely to occur. In this case, the angular error value caused by the amount of tilt of the axis in the positive Y-axis direction is not calculated, and no angular correction is performed. Also, if the rotation axis of motor 1 is tilted in both the positive X-axis direction and the positive Y-axis direction, angular errors will occur. In this case, only the angular error value caused by the amount of tilt of the axis in the positive X-axis direction is calculated, and angular correction is performed based on the calculated angular error value.

[0084] Here, the phase characteristic of the eccentricity (amount of eccentricity) is a sine function, and the amplitude of the sine function increases or decreases in proportion to the amount of eccentricity. Even with the same amount of eccentricity in the X-axis and Y-axis directions, the amplitudes of the X and Y signals are not the same, and the relationship is that the amplitude of the Y signal > the amplitude of the X signal. For example, when calculating the angular error value caused by the tilt of the axis in the positive X-axis direction, angular correction is performed based on the calculated angular error value, but the angular error value caused by the tilt of the axis in the positive Y-axis direction is not calculated and no angular correction is performed.

[0085] This function to correct such angular errors can be implemented by the control unit, such as a processor or microcomputer, of the control system 3.

[0086] The functional configuration of control system 3 has been explained above.

[0087] Next, the functional configuration of the display unit 80 will be described.

[0088] The display unit 80 displays the status of the encoder 10 as a result of the determination made by the determination circuit 62. For example, the display unit 80 indicates an abnormality when the DC component of the X signal and the DC component of the Y signal exceed a predetermined threshold. In other words, as described above, the display unit 80 indicates that the rotation shaft load is excessive when the total motor operating time is less than or equal to the first set time and the DC component of the X signal or the DC component of the Y signal exceeds the second threshold.

[0089] Furthermore, the display unit 80 indicates that there is an abnormality in the motor 1 when the total motor operating time exceeds the first set time and is less than or equal to the second set time, and the DC component of the X signal or the DC component of the Y signal exceeds the first threshold.

[0090] Furthermore, the display unit 80 indicates a bearing failure in motor 1 when the total motor operating time exceeds the second set time and the DC component of the X signal or the DC component of the Y signal exceeds the third threshold.

[0091] The display unit 80 may be, for example, a liquid crystal display, an organic EL (Electro-Luminescence) display, or a tablet terminal or monitor equipped with such a display.

[0092] The functional configuration of the display unit 80 has been described above.

[0093] Next, we will explain the effects of control system 3.

[0094] The encoder 10 according to this embodiment includes an emission unit 40 that emits light, a rotating plate 20 which is provided so as to surround the rotation axis A of the rotating plate 20 and has an annular region 26 that reflects or transmits light emitted from the emission unit 40, a light receiving unit 50 that receives light emitted from the emission unit 40 and that has passed through the annular region 26, a signal processing circuit 61 that processes the signal from the light receiving unit 50, and a determination circuit 62 that determines an abnormality based on the output result processed by the signal processing circuit 61. The light receiving unit 50 also includes a first set having a first light receiving region 55 and a second light receiving region 56 arranged in a first direction intersecting the rotation direction C of the rotating plate 20, and a second set having a third light receiving region 57 and a fourth light receiving region 58 arranged in a second direction intersecting the rotation direction C and provided alongside the first set in the rotation direction C.

[0095] According to this, as the rotating plate 20 rotates, the signal processing circuit 61 processes the signals from the light receiving area to detect changes in the position of the light received by the first light receiving area 55, the second light receiving area 56, the third light receiving area 57, and the fourth light receiving area 58, thereby accurately detecting the eccentricity of the rotating plate 20. It can also accurately detect whether there is an angle deviation around the axis of the rotation shaft of the motor 1. Therefore, the judgment circuit 62 can detect an abnormality in the rotation shaft from the output result processed by the signal processing circuit 61.

[0096] Therefore, in this embodiment, abnormalities can be diagnosed with a simple configuration without the need for additional equipment such as vibration sensors and information terminal devices for diagnosing abnormalities.

[0097] Furthermore, in the encoder 10 according to this embodiment, when the signal value corresponding to the light received by the first light-receiving area 55 is set to A1, the signal value corresponding to the light received by the second light-receiving area 56 is set to A2, the signal value corresponding to the light received by the third light-receiving area 57 is set to B1, and the signal value corresponding to the light received by the fourth light-receiving area 58 is set to B2, the signal processing circuit 61 processes the signal indicating the value of X and the signal indicating the value of Y as follows, and the determination circuit 62 monitors whether the change in the DC component of the signal indicating the value of X and the DC component of the signal indicating the value of Y exceeds a predetermined threshold, and the values ​​of X and Y satisfy the following relationship.

[0098] X = (A1 + B2) - (B1 + A2) Y=(A1+B1)-(A2+B2)

[0099] According to this, a signal corresponding to the position of the rotating plate 20 can be output, allowing for more accurate detection of the eccentricity of the rotating plate 20 relative to the motor 1. Furthermore, it is possible to accurately detect whether there is an angle deviation around the axis of the motor 1's rotation shaft. Therefore, abnormalities in the rotation shaft can be diagnosed with greater accuracy using a simple configuration.

[0100] Furthermore, in the encoder 10 according to this embodiment, different predetermined thresholds are set for the DC component of the signal indicating the value of X and the DC component of the signal indicating the value of Y.

[0101] According to this method, thresholds can be set according to the DC component of the signal indicating the X value and thresholds according to the DC component of the signal indicating the Y value. Therefore, it is possible to detect with greater accuracy when there is an angular displacement around the axis of rotation.

[0102] Furthermore, in the control system 3 according to this embodiment, an abnormality is detected using the sensor of the light receiving unit 50.

[0103] According to this, abnormalities can be diagnosed with a simple configuration.

[0104] Furthermore, in the control system 3 according to this embodiment, the predetermined threshold includes a first threshold. The control system 3 also includes an encoder 10 and a display unit 80 that displays an abnormality when the DC component of the signal indicating the value of X and the DC component of the signal indicating the value of Y exceed the first threshold.

[0105] According to this, the display unit 80 can indicate that there is an abnormality in the rotating shaft. Therefore, a person can recognize that there is an abnormality in the rotating shaft.

[0106] Furthermore, in the control system 3 according to this embodiment, the predetermined threshold includes a second threshold. Also, when the total operating time of the motor mounted on the encoder 10 is less than or equal to the first set time, and the DC component of the signal indicating the value of X or the DC component of the signal indicating the value of Y exceeds the second threshold, the display unit 80 indicates that the rotation shaft load is excessive.

[0107] For example, if the total motor operating time is less than or equal to the first set time, it is considered that the total motor operating time is short, and therefore the wear on the bearings used in the motor is considered to be low. For this reason, it is considered that too much load is being placed on the motor's rotating shaft, causing eccentricity in the rotating shaft.

[0108] Therefore, in this embodiment, the display unit 80 can display that the rotational shaft load is excessive in such cases. As a result, a person can recognize that the rotational shaft load is excessive.

[0109] Furthermore, in the control system 3 according to this embodiment, the predetermined threshold includes a third threshold. Also, when the total operating time of the motor mounted on the encoder 10 exceeds the second set time, and the DC component of the signal indicating the value of X and the DC component of the signal indicating the value of Y exceed the third threshold, the display unit 80 indicates that there is a bearing failure.

[0110] For example, if the total motor operating time exceeds the first set time, it is considered that the total motor operating time is long, and therefore wear on the bearings used in motor 1 is occurring, causing eccentricity of the rotating shaft.

[0111] Therefore, in this embodiment, the display unit 80 can display that the bearing is faulty in such cases. As a result, a person can recognize that the bearing is faulty.

[0112] Furthermore, the control system 3 according to this embodiment includes a function that rotates the rotation axis of the motor 1 by one or more revolutions in order for the determination circuit 62 to determine an abnormality based on the output of the signal processing circuit 61.

[0113] According to this, when the control system 3 rotates the motor 1's rotation axis by one or more revolutions, the determination circuit 62 can determine whether or not there is an abnormality in the rotation axis.

[0114] Furthermore, the control system 3 according to this embodiment includes a dedicated operating mode that rotates the motor 1's rotation axis by one or more revolutions in order to detect abnormalities.

[0115] According to this, when the control system 3 executes a dedicated operating mode, the determination circuit 62 can determine whether or not there is an abnormality in the rotating shaft.

[0116] Furthermore, the control system 3 according to this embodiment includes a function to determine the amount of tilt of the rotation axis and the direction of tilt of the rotation axis from the sign and absolute value of the DC offset of the signal indicating the X value and the signal indicating the Y value, respectively, obtained by rotating the rotation axis of the motor 1 once.

[0117] According to this, the amount and direction of the tilt of the axis of rotation can be determined.

[0118] Furthermore, the control system 3 according to this embodiment includes a function to determine the amount of inclination of the axis of rotation from the sign and absolute value of the DC offset of the signal indicating the value of X obtained by rotating the rotation axis of the motor 1 once, and to correct the angular error caused by the amount of inclination.

[0119] According to this method, by calculating the amount of tilt of the rotation axis in the X-axis direction and the direction of the tilt of the rotation axis, the DC offset of the signal indicating the value of X can be calculated with greater accuracy.

[0120] (Second Embodiment) Figure 8 is a block diagram showing the functional configuration of the encoder 10a according to the second embodiment. The configuration of the encoder 10a according to the second embodiment will be described with reference to Figure 8. In the second embodiment, the same reference numerals are used for the same components and functions as in the first embodiment, and detailed explanations of these components and functions are omitted. In the following, the differences from the encoder 10 according to the first embodiment will be mainly described.

[0121] First, the functional configuration of the encoder 10a in the control system 3 according to the second embodiment will be described.

[0122] As shown in Figure 8, the encoder 10a further comprises an output unit 60 and a calculation unit 70.

[0123] The output unit 60 outputs a signal corresponding to the light received by the light receiving unit 50. Specifically, the output unit 60 outputs a signal corresponding to the light received by the first absolute light receiving area 51, a signal corresponding to the light received by the second absolute light receiving area 52, a signal corresponding to the light received by the first incremental light receiving area 53, a signal corresponding to the light received by the second incremental light receiving area 54, a signal corresponding to the light received by the first light receiving area 55, a signal corresponding to the light received by the second light receiving area 56, a signal corresponding to the light received by the third light receiving area 57, and a signal corresponding to the light received by the fourth light receiving area 58. For example, the output unit 60 outputs a signal corresponding to the intensity of the light received by the light receiving unit 50.

[0124] The output unit 60 outputs a signal indicating the following X value and a signal indicating the Y value, when the signal value corresponding to the light received by the first light-receiving area 55 is set as A1, the signal value corresponding to the light received by the second light-receiving area 56 is set as A2, the signal value corresponding to the light received by the third light-receiving area 57 is set as B1, and the signal value corresponding to the light received by the fourth light-receiving area 58 is set as B2.

[0125] Furthermore, the output unit 60 outputs a signal indicating the following Q values.

[0126] Q = A1 + B1 + A2 + B2

[0127] Furthermore, the output unit 60 outputs a signal indicating the value of X1 and a signal indicating the value of Y1.

[0128] X1 = X / Q Y1 = Y / Q

[0129] The calculation unit 70 calculates the following value of P1, where P is the rotation angle (angle address) of the rotating plate 20 detected based on the light emitted from the emission unit 40 and received by one or more light-receiving regions via one or more patterns, Δr (see Figure 9) is the eccentricity of the axis B of the annular region 26 with respect to the rotation axis A, Φ (see Figure 9) is the eccentric phase of the axis B of the annular region 26 with respect to the rotation axis A, and r (see Figure 9) is the radius of the annular region 26. As described above, in this embodiment, the one or more patterns are the first absolute pattern 22, the second absolute pattern 23, the first incremental pattern 24, and the second incremental pattern 25, and the one or more light-receiving regions are the first absolute light-receiving region 51, the second absolute light-receiving region 52, the first incremental light-receiving region 53, and the second incremental light-receiving region 54.

[0130] P1 = P + tan -1 (Δr × sinΦ / r) Alternatively, P1 = P - tan -1 (Δr × sinΦ / r)

[0131] For example, the calculation unit 70 calculates P1 = P + tan when Φ = 0 to π / 2 and when Φ = 3π / 2 to 2π. -1 The value of P1 is calculated using (Δr × sinΦ / r).

[0132] Furthermore, for example, if Φ = π / 2 to 3π / 2, the calculation unit 70 calculates P1 = P - tan. -1 The value of P1 is calculated using (Δr × sinΦ / r).

[0133] Furthermore, for example, if the value of Y calculated by Y=(A1+B1)-(A2+B2) is positive, the calculation unit 70 calculates P1=P+tan -1 The value of P1 is calculated using (Δr × sinΦ / r).

[0134] Furthermore, for example, if the value of Y calculated by Y=(A1+B1)-(A2+B2) is negative, the calculation unit 70 calculates P1=P-tan -1 The value of P1 is calculated using (Δr × sinΦ / r).

[0135] Details of the calculation method used by the calculation unit 70 will be described later.

[0136] The output unit 60 outputs a signal indicating the value of P1 calculated by the calculation unit 70.

[0137] The functional configuration of encoder 10a has been explained above.

[0138] Next, with reference to Figures 9 to 11, the signals output by the output unit 60 will be described.

[0139] Figure 9 is a schematic diagram showing a state in which the axis B of the annular region 26 is eccentric with respect to the rotation axis A. Figure 10 is a schematic diagram showing an example of the change in the position of the light (see H in Figure 10) irradiated onto the first light-receiving region 55, the second light-receiving region 56, the third light-receiving region 57, and the fourth light-receiving region 58 as the rotating plate 20 rotates, in a state in which the axis B of the annular region 26 is eccentric with respect to the rotation axis A. Figure 11 is a graph showing an example of the signal output by the output unit 60 as the rotating plate 20 rotates, in a state in which the axis B of the annular region 26 is eccentric with respect to the rotation axis A.

[0140] As shown in Figure 9, when the axis B of the annular region 26 is eccentric with respect to the rotation axis A, the position of the light irradiated onto the first light-receiving region 55, the second light-receiving region 56, the third light-receiving region 57, and the fourth light-receiving region 58 via the annular region 26 changes as the rotating plate 20 rotates.

[0141] For example, when the rotating plate 20 is located at the position indicated by T1 in Figure 10, the position of the light when the axis B of the annular region 26 is eccentric with respect to the rotation axis A is located on one side in the Y-axis direction compared to the position of the light when the axis B of the annular region 26 is not eccentric with respect to the rotation axis A (see the dashed line in Figure 10).

[0142] Furthermore, for example, if the rotating plate 20 is located at the position indicated by T2 in Figure 10, the position of the light when the axis B of the annular region 26 is eccentric with respect to the rotation axis A is located on one side in the X-axis direction compared to the position of the light when the axis B of the annular region 26 is not eccentric with respect to the rotation axis A (see the dashed line in Figure 10).

[0143] Furthermore, for example, when the rotating plate 20 is located at the position indicated by T3 in Figure 10, the position of the light when the axis B of the annular region 26 is eccentric with respect to the rotation axis A is located on the other side in the Y-axis direction compared to the position of the light when the axis B of the annular region 26 is not eccentric with respect to the rotation axis A (see the dashed line in Figure 10).

[0144] Furthermore, for example, when the rotating plate 20 is located at the position indicated by T4 in Figure 10, the position of the light when the axis B of the annular region 26 is eccentric with respect to the rotation axis A is located on the other side in the X-axis direction compared to the position of the light when the axis B of the annular region 26 is not eccentric with respect to the rotation axis A (see the dashed line in Figure 10).

[0145] As shown in Figure 11, when the axis B of the annular region 26 is eccentric with respect to the rotation axis A, the output unit 60 outputs a signal indicating the displacement in the X-axis direction and a signal indicating the displacement in the Y-axis direction when the rotating plate 20 rotates. This indicates that the axis B of the annular region 26 is eccentric with respect to the rotation axis A. In the following explanation, the signal indicating the displacement in the X-axis direction may be referred to as the first signal, and the signal indicating the displacement in the Y-axis direction may be referred to as the second signal.

[0146] The signals output by the output unit 60 have been described above.

[0147] Next, with reference to Figure 12A, an example of the calculation method of the calculation unit 70 will be described.

[0148] Figure 12A is a flowchart showing an example of the calculation method of the calculation unit 70 of the encoder 10a in Figure 2.

[0149] As shown in Figure 12A, first, the calculation unit 70 matches the amplitude of the first signal with the amplitude of the second signal (step S1). As described above, the first signal is a signal indicating the shift in the X-axis direction, and the second signal is a signal indicating the shift in the Y-axis direction.

[0150] The calculation unit 70 matches the amplitude of the first signal with the amplitude of the second signal and determines the eccentric phase of axis B with respect to the rotation axis A and the amount of eccentricity of axis B with respect to the rotation axis A (step S2). For example, the eccentric phase of axis B with respect to the rotation axis A is calculated using the X value indicated by the first signal and the Y value indicated by the second signal. Alternatively, for example, the amount of eccentricity of axis B with respect to the rotation axis A is calculated from the amplitude of the first signal. Alternatively, for example, the amount of eccentricity of axis B with respect to the rotation axis A is calculated from a pre-prepared table or function. The amplitude for calculating the amount of eccentricity may be determined sequentially from the square root of the sum of the squares of the first and second signals whose amplitudes have been matched. Specifically, for example, if the amplitude for calculating the amount of eccentricity is G, G may be calculated in real time using the following formula.

[0151]

number

[0152] The calculation unit 70 determines the eccentric phase and eccentricity amount, and then calculates the angle (step S3). For example, when the true detection address is P1, P1 = P ± tan -1 The true detection address is calculated using (Δr × sinΦ / r). Here, as described above, P is the rotation angle of the rotating plate 20 detected based on the light emitted from the emission unit 40 and received by the light receiving unit 50 via one or more patterns, r is the radius of the annular region 26, Δr is the eccentricity of the axis B of the annular region 26 with respect to the rotation axis A, and Φ is the eccentric phase of the axis B of the annular region 26 with respect to the rotation axis A.

[0153] The above describes an example of the calculation method of the calculation unit 70.

[0154] Figure 12B is a flowchart showing another example of the calculation method of the calculation unit 70 of the encoder 10a in Figure 2. Referring to Figure 12B, another example of the calculation method of the calculation unit 70 will be explained. Note that the following explanation will mainly focus on the differences from the example calculation method shown in Figure 12A.

[0155] As shown in Figure 12B, first, the calculation unit 70 acquires the amplitude of the second signal (step S11). For example, the calculation unit 70 acquires the amplitude of the second signal from one rotation prior. For example, the calculation unit 70 acquires the amplitude of the second signal from one rotation in test mode or from one rotation during continuous rotation. Specifically, for example, the calculation unit 70 acquires the amplitude of the second signal from data of any 360 degrees. Alternatively, for example, the calculation unit 70 acquires the amplitude of the second signal by clipping the peak value from data of any 180 degrees.

[0156] When the calculation unit 70 acquires the amplitude of the second signal, it determines the eccentric phase of axis B with respect to the rotation axis A and the amount of eccentricity of axis B with respect to the rotation axis A (step S2). For example, the calculation unit 70 estimates the waveform of the second signal from the acquired amplitude of the second signal and determines the eccentric phase of axis B with respect to the rotation axis A from the Y value indicated by the second signal output from the output unit 60 and the trend of increase or decrease in the signal level of the second signal.

[0157] Thus, the calculation unit 70 may calculate the eccentric phase of the axis B with respect to the rotation axis A without using the first signal.

[0158] The above describes another example of the calculation method of the calculation unit 70.

[0159] As described above, the encoder 10a can detect the eccentricity of the rotating plate 20 relative to the motor 1 with greater accuracy. Furthermore, since the encoder 10a can provide the first light-receiving area 55, the second light-receiving area 56, the third light-receiving area 57, and the fourth light-receiving area 58 on a single substrate 30, a smaller and less expensive encoder 10a can be provided.

[0160] The encoder 10a according to the second embodiment has been described above.

[0161] Next, using Figure 13A, we will explain the functional configuration for correcting the position signal based on the Y signal.

[0162] Figure 13A shows the noise contained in the Y signal and the Y signal after fitting.

[0163] Typically, the Y signal is a signal superimposed with noise, as shown by the dot hatching in Figure 13A. In this case, the error is large, so it is necessary to extract the error with high accuracy. Specifically, the control system 3 acquires the Y signal by rotating the rotating plate 20 once with the motor 1, and corrects the position signal of the encoder 10a, which indicates the position of the rotating plate 20 (the center position of the rotating plate 20), based on the acquired angular error. Specifically, the control system 3 performs fitting on the acquired Y signal. The fitting is performed, for example, using the least squares method. The fitting may also be performed using a sine function, or if there are multiple noises in the Y signal, a function obtained by superimposing two or more sine waves may be used, or a polynomial may be used for approximation.

[0164] The control system 3 calculates the angular error value by generating an angular error correction function based on the fitted Y signal. Specifically, the control system 3 calculates the angular error value by setting an angular error correction table based on the generated angular error correction function. For example, the control system 3 extracts the amplitude and phase of the fitted Y signal, or the DC offset to the DC component of the fitted Y signal, and calculates the angular error value based on the extracted information. Based on the calculated angular error value, the control system 3 corrects the position signal of the encoder 10, which indicates the position of the rotating plate 20. In other words, the control system 3 performs angular correction based on the signal (position signal) indicating the center position shift of the rotating plate 20 in the Y-axis direction, obtained from the first light-receiving area 55, the second light-receiving area 56, the third light-receiving area 57, and the fourth light-receiving area 58 of the encoder 10. These processes may also be performed by the signal processing circuit 61 or the determination circuit 62.

[0165] The above describes the functional configuration for correcting angular error values ​​based on the Y signal.

[0166] Next, with reference to Figure 13B, an example of a method for angle correction based on the Y signal will be described.

[0167] Figure 13B is a flowchart showing an example of an angle correction method.

[0168] In control system 3, angle correction values ​​can be set by periodically executing maintenance mode before or during use. Maintenance mode is a function that corrects angle error values ​​and is a function provided by control system 3.

[0169] Therefore, as shown in Figure 13B, the user operates the control system 3 to execute a maintenance mode for angle correction (S1a).

[0170] Next, the control system 3 executes maintenance mode to generate a Y signal that causes the motor 1 to rotate the plate 20 at least once. Then, the control system 3 measures the phase characteristics of the acquired Y signal (S2a).

[0171] Next, the control system 3 performs fitting to the Y signal (S3a). Specifically, the control system 3 uses the sine function C × sin(Θ + α) + β to perform fitting to the Y signal. α is a constant that represents the phase offset that occurs when the rotating plate is attached to the motor. β is a constant that represents the DC offset of the Y signal. C is a constant that represents the amplitude of the signal (position signal) obtained in the first light-receiving area 55, the second light-receiving area 56, the third light-receiving area 57, and the fourth light-receiving area 58 of the encoder 10.

[0172] Next, the control system 3 generates an angular error correction function that represents the fitted Y signal (S4a). The angular error correction function is, for example, represented by K × C × sin(Θ + 90 + α) + β. K is a pre-set value and is a constant that represents the amount of deviation of the signal. The angular error correction function makes it possible to calculate the angular error value mentioned above.

[0173] Next, the control system 3 sets an angle error correction table based on the generated angle error correction function (S5a). Once the angle error correction table is set, angle correction can be performed. After setting the angle error correction table, the control system 3 returns the motor 1 to its normal operating mode.

[0174] The above describes one example of a method for angle correction based on the Y signal.

[0175] Next, with reference to Figure 13C, another example of a method for angle correction based on the Y signal will be described. Note that explanations of processes identical to those in Figure 13B may be omitted as appropriate. Figure 13C differs from Figure 13B in that it also acquires the X signal, among other things.

[0176] Figure 13C is a flowchart showing another example of an angle correction method.

[0177] First, after step S1a, the control system 3 executes a maintenance mode, causing the motor 1 to rotate the plate 20 at least once and acquire the X and Y signals. The control system 3 then measures the phase characteristics of the acquired X and Y signals (S2b).

[0178] Next, the control system 3 performs a fitting on the Y signal to obtain only the constant term γ for the X signal (S3b). The constant term γ is the DC offset of the X signal. The fitting on the Y signal is performed using the sine function C × sin(Θ + α) + β. Alternatively, the control system 3 may perform a fitting on the X signal to obtain the DC offset of the X signal.

[0179] Next, the control system 3 returns the motor 1 to a normal operating mode via steps S4a and S5a.

[0180] The above describes another example of a method for angle correction based on the Y signal.

[0181] Next, referring to Figure 13D, we will explain how to determine whether or not there is an abnormality using the constant term γ obtained in step S3b of Figure 13C.

[0182] Figure 13D is a flowchart showing an example of a method for determining the presence or absence of abnormalities using the constant term γ.

[0183] First, the control system 3 stores the γ obtained in step S3b of Figure 13C (S31b). The stored constant term γ is sometimes called γ0. The obtained constant term γ is stored, for example, in the memory of the signal processing circuit 61 or the decision circuit 62, or in a memory unit installed in the control system 3.

[0184] Next, the control system 3 further performs steps S2b and S3b in Figure 13C to acquire a new constant term γ (S32b). The newly acquired constant term γ is sometimes called γ1.

[0185] Next, the control system 3 determines whether γ0 ≠ γ1 by comparing γ0 and γ1 (S33b). This is because the constant term γ may shift due to the use of the rotating plate 20 for a certain period of time, so the system compares the previously determined γ0 with the γ1 determined after that period. In this way, it is possible to determine whether there is an abnormality in the rotating plate 20 based on the change in the constant term γ over time. Here, the certain period can be several days, several weeks, several months, several years, etc.

[0186] If the control system 3 determines that γ0 ≠ γ1 (YES in S33b), it determines that the rotating plate 20 is abnormal (S34b). The control system 3 outputs the determination result to the display unit 80, which displays that the rotating plate 20 is abnormal. The control system 3 then terminates the processing of the flowchart in Figure 13D.

[0187] On the other hand, if the control system 3 determines that γ0 ≠ γ1 is not true (NO in S33b), it determines that the rotating plate 20 is functioning normally (S35b). The control system 3 outputs the determination result to the display unit 80, which displays that the rotating plate 20 is functioning normally. The control system 3 then completes the processing shown in the flowchart in Figure 13D.

[0188] Furthermore, in the comparison between γ0 and γ1, if γ0 and γ1 are identical or substantially identical, the control system 3 may determine that γ0 ≠ γ1. Substantially identical γ0 and γ1 include an error of a few percent.

[0189] In Figure 13D, the constant term γ is used to determine whether the rotating plate 20 is abnormal or not, but β may also be used to determine whether the rotating plate 20 is abnormal or not. Therefore, γ in Figure 13D can be replaced with β.

[0190] The above explains how to determine whether or not there is an abnormality.

[0191] Next, the effects and benefits of the encoder 10a according to the second embodiment will be described.

[0192] The encoder 10a according to the second embodiment includes an emission unit 40 that emits light, a rotating plate 20 which is provided so as to surround the rotation axis A of the rotating plate 20 and has an annular region 26 that reflects the light emitted from the emission unit 40, and a light receiving unit 50 that receives the light emitted from the emission unit 40 and that has passed through the annular region 26. The light receiving unit 50 has a first set having a first light receiving region 55 and a second light receiving region 56 arranged in a first direction E that intersects the rotation direction C of the rotating plate 20, and a second set having a third light receiving region 57 and a fourth light receiving region 58 arranged in a second direction F that intersects the rotation direction C, and provided alongside the first set in the rotation direction C.

[0193] According to this, the device has a first set having a first light-receiving region 55 and a second light-receiving region 56 aligned in a first direction E that intersects the rotation direction C of the rotating plate 20, and a second set having a third light-receiving region 57 and a fourth light-receiving region 58 aligned in a second direction F that intersects the rotation direction C, and provided alongside the first set in the rotation direction C. As a result, as the rotating plate 20 rotates, the position of the light received by the first light-receiving region 55, the second light-receiving region 56, the third light-receiving region 57, and the fourth light-receiving region 58 changes, allowing for accurate detection of the eccentricity of the rotating plate 20 relative to the motor 1.

[0194] Furthermore, the encoder 10a according to the second embodiment further includes an output unit 60 that outputs a signal showing the following Y values ​​when the signal value corresponding to the light received by the first light receiving area 55 is A1, the signal value corresponding to the light received by the second light receiving area 56 is A2, the signal value corresponding to the light received by the third light receiving area 57 is B1, and the signal value corresponding to the light received by the fourth light receiving area 58 is B2.

[0195] Y=(A1+B1)-(A2+B2)

[0196] According to this, a signal corresponding to the position of the rotating plate 20 can be output, allowing for more accurate detection of the eccentricity of the rotating plate 20 relative to the motor 1.

[0197] Furthermore, in the encoder 10a according to the second embodiment, the output unit 60 outputs a signal indicating the following Q value.

[0198] Q = A1 + B1 + A2 + B2

[0199] According to this, a signal corresponding to the position of the rotating plate 20 can be output, allowing for more accurate detection of the eccentricity of the rotating plate 20 relative to the motor 1.

[0200] Furthermore, in the encoder 10a according to the second embodiment, the output unit 60 further outputs a signal indicating the value of X, a signal indicating the value of X1, and a signal indicating the value of Y1.

[0201] X = (A1 + B2) - (B1 + A2) X1 = X / Q Y1 = Y / Q

[0202] According to this, since a signal corresponding to the position of the rotary plate 20 can be output, the eccentricity of the rotary plate 20 with respect to the motor 1 can be detected more accurately.

[0203] Also, in the encoder 10a according to the second embodiment, the rotary plate 20 has one or more patterns for detecting the rotation angle of the rotary plate 20, the light receiving unit 50 has one or more light receiving regions for receiving the light emitted from the light emitting unit 40 and passing through the one or more patterns, and the rotation angle of the rotary plate 20 detected based on the light received by the one or more light receiving regions after being emitted from the light emitting unit 40 and passing through the one or more patterns is defined as P, the eccentricity amount of the axis B of the annular region 26 with respect to the rotation axis A is defined as Δr, the eccentricity phase of the axis B with respect to the rotation axis A is defined as Φ, and the radius of the annular region 26 is defined as r. Further provided is a calculation unit 70 for calculating the following value of P1. P1 = P + tan -1 (Δr × sin Φ / r) Or, P1 = P - tan -1 (Δr × sin Φ / r)

[0204] The output unit 60 outputs a signal indicating the value of P1 calculated by the calculation unit 70.

[0205] According to this, even when the rotary plate 20 is eccentric with respect to the motor 1, the correct position of the motor 1 can be detected.

[0206] Also, the encoder 10a according to the present embodiment rotates the rotary plate 20 once by the motor 1 to acquire a signal indicating the value of Y, acquires the angle error of the rotary plate 20 based on the acquired signal indicating the value of Y, and corrects the position signal of the encoder 10a indicating the position of the rotary plate 20 based on the acquired angle error.

[0207] According to this, the angular error of the rotating plate 20 in the encoder 10 can be obtained based on the Y signal, and therefore the positional error due to the eccentricity of the rotating plate 20 can be corrected. As a result, even if the rotating plate 20 is eccentric, the correct position can be detected.

[0208] Furthermore, the encoder 10a according to this embodiment has a function to correct the position signal of the encoder 10a indicating the position of the rotating plate 20 by fitting the acquired signal indicating the Y value, generating an angle error correction function for determining the angle error of the rotating plate 20 based on the fitted signal indicating the Y value, and setting an angle error correction table based on the generated angle error correction function.

[0209] According to this method, an angle error correction table can be set by generating an angle error correction function based on the Y signal. Therefore, the position error due to eccentricity of the rotating plate 20 can be corrected using the newly set angle error correction table. As a result, even if the rotating plate 20 is eccentric, a more accurate position can be detected.

[0210] Furthermore, in the encoder 10a according to this embodiment, the output unit 60 further outputs a signal indicating the following value of X.

[0211] X = (A1 + B2) - (B1 + A2)

[0212] Furthermore, the encoder 10a has a function to rotate the rotating plate 20 once with the motor 1 to acquire a signal indicating the value of X, to determine γ0 which is the DC offset of the acquired signal indicating the value of X, and to store the γ0 of the acquired signal indicating the value of X.

[0213] According to this, the DC offset γ0 of the X signal can be stored in advance. Therefore, if a new DC offset of the X signal is determined later, it can be used to compare the past DC offset with the current DC offset.

[0214] Furthermore, the encoder 10a according to this embodiment has a function to determine whether or not there is an abnormality based on whether or not γ0 and γ1 match, by rotating the rotating plate 20 once with the motor 1 after a certain period of time has elapsed since determining γ0, thereby acquiring a signal indicating the value of X, and determining the DC offset γ1 of the signal indicating the value of X.

[0215] According to this method, after using motor 1 for a certain period of time, it is possible to determine whether or not there is an abnormality in the rotating plate 20 of motor 1 by comparing the state of the rotating plate 20 of motor 1 in the past with the state of the rotating plate 20 of motor 1 in the present.

[0216] Furthermore, in the encoder 10a according to the second embodiment, the first set and the second set are provided with the ejection section 40 in the rotation direction C.

[0217] According to this, the decrease in the amount of light received by the first light-receiving area 55, the second light-receiving area 56, the third light-receiving area 57, and the fourth light-receiving area 58 can be suppressed, so the eccentricity of the rotating plate 20 relative to the motor 1 can be detected with even greater accuracy.

[0218] Furthermore, in the encoder 10a according to the second embodiment, the first direction E and the second direction F are directions parallel to a straight line G perpendicular to the rotation axis A, and the first set and the second set are arranged symmetrically with respect to the straight line G as the axis of symmetry.

[0219] Since the amount of light received by the first light-receiving area 55, the second light-receiving area 56, the third light-receiving area 57, and the fourth light-receiving area 58 is reduced and variations in light intensity are suppressed, the eccentricity of the rotating plate 20 relative to the motor 1 can be detected with even greater accuracy.

[0220] Furthermore, in the encoder 10a according to the second embodiment, the dimension L from the end of the first light-receiving region 55 opposite to the second light-receiving region 56 in the first direction E is greater than the dimension W2 in the first direction E of the light emitted from the emission unit 40 and irradiated onto the first light-receiving region 55 and the second light-receiving region 56 via the annular region 26, and the dimension from the end of the third light-receiving region 57 opposite to the fourth light-receiving region 58 in the second direction F is greater than the dimension in the second direction F of the light emitted from the emission unit 40 and irradiated onto the third light-receiving region 57 and the fourth light-receiving region 58 via the annular region 26.

[0221] According to this, when the rotating plate 20 is eccentric with respect to the motor 1, the position of the light received by the first light-receiving area 55 and the second light-receiving area 56, and the position of the light received by the third light-receiving area 57 and the fourth light-receiving area 58 can be appropriately changed as the rotating plate 20 rotates, so that the eccentricity of the rotating plate 20 with respect to the motor 1 can be detected with even greater accuracy.

[0222] Furthermore, in the encoder 10a according to the second embodiment, the emission unit 40 has a point light source, and the dimension between the annular region 26 in the axial direction to which the rotation axis A extends and the emission unit 40 is h1, the dimension between the annular region 26 in the axial direction to which the rotation axis A extends and the first light-receiving region 55 and the second light-receiving region 56 is h2, the dimension from the end of the first light-receiving region 55 opposite to the second light-receiving region 56 in the first direction E is L, the dimension of the annular region 26 in the first direction E is W1, and the dimension of the light emitted from the point light source and irradiated onto the first light-receiving region 55 and the second light-receiving region 56 via the annular region 26 in the first direction E is W2, then W2 = (h2 / h1) × W1 and W2 / L < 1.

[0223] According to this, when the rotating plate 20 is eccentric with respect to the motor 1, the position of the light received by the first light-receiving area 55 and the second light-receiving area 56 can be appropriately changed as the rotating plate 20 rotates, so that the eccentricity of the rotating plate 20 with respect to the motor 1 can be detected with even greater accuracy.

[0224] Furthermore, in the encoder 10a according to the second embodiment, the Y signal can also be obtained from only the first set or only the second set. For example, after obtaining the Y signal from the first set as Y = A1 - A2, the angle error amount can be calculated based on the obtained Y signal.

[0225] According to this, the angular error can be calculated with the minimum number of photodetectors, which allows for miniaturization of the substrate 30 and simplification of signal processing.

[0226] Furthermore, in the encoder 10a according to the second embodiment, the Y signal can be obtained from only the first set and only the second set, and then the Y signals obtained from the two sets can be compared. For example, a first Y signal YA can be obtained from the first set as YA=A1-A2, and a second Y signal YB can be obtained from the second set as YB=B1-B2. Based on these signals, the angular error can be calculated, compared, or the average can be calculated.

[0227] According to this method, the amount of angular error can be extracted and compared using two types of measurements, allowing for highly accurate correction of angular errors and providing redundancy in error calculation.

[0228] (Third embodiment) Figure 14 is a schematic diagram of the rotating plate 20a of the encoder according to the third embodiment, viewed from the axial direction. Figure 15 is a schematic diagram of the light-emitting section 40a and light-receiving section 50a of the encoder in Figure 14, viewed from the axial direction. The configuration of the encoder according to the third embodiment will be described with reference to Figures 14 and 15. In the third embodiment, the same reference numerals are used for the same components and functions as in the second embodiment, and detailed explanations of these components and functions are omitted. In the following, the differences from the encoder 10a according to the second embodiment will be mainly described.

[0229] Note that in Figure 14, only half of the rotating plate 20a is shown to avoid making the drawing too complex.

[0230] As shown in Figure 14, the encoder according to the third embodiment is equipped with a rotating plate 20a that is different from the rotating plate 20. Also, as shown in Figure 15, the encoder according to the third embodiment is equipped with an output unit 40a that is different from the output unit 40 and a light receiving unit 50a that is different from the light receiving unit 50. The encoder according to the third embodiment differs from the encoder 10a in these respects.

[0231] As shown in Figure 14, the rotating plate 20a has a main body 21, an absolute pattern 22a, an incremental pattern 24a, and an annular region 26a.

[0232] The annular region 26a is an annular region provided so as to surround the axis of rotation A and reflects the light emitted from the emission section 40a. The annular region 26a reflects the light emitted from the emission section 40a toward the light receiving section 50a. The annular region 26a is provided on the main surface of the main body 21 on the side of the emission section 40a. The direction in which the axis B of the annular region 26a extends coincides with the axial direction. For example, the annular region 26a is composed of continuously arranged annular reflective sections that reflect the light emitted from the emission section 40a toward the light receiving section 50a.

[0233] As shown in Figure 15, the emission unit 40a emits light. Specifically, the emission unit 40a emits light toward the rotating plate 20a. More specifically, the emission unit 40a emits light toward the absolute pattern 22a, the incremental pattern 24a, and the annular region 26a. The emission unit 40a is provided on the main surface of the substrate 30 on the rotating plate 20a side.

[0234] The light-receiving unit 50a receives light emitted from the emission unit 40a and passing through the annular region 26a. The light-receiving unit 50a has a first absolute light-receiving region 51a, a second absolute light-receiving region 52a, a first incremental light-receiving region 53a, a second incremental light-receiving region 54a, a first set, and a second set.

[0235] The first absolute light-receiving region 51a and the second absolute light-receiving region 52a each receive light emitted from the emission section 40a and that has passed through the absolute pattern 22a. The first absolute light-receiving region 51a and the second absolute light-receiving region 52a are arranged offset from each other in the rotational direction C.

[0236] The first incremental light-receiving area 53a and the second incremental light-receiving area 54a each receive light emitted from the emission section 40a and that has passed through the incremental pattern 24a. The first incremental light-receiving area 53a and the second incremental light-receiving area 54a are arranged offset from each other in the rotational direction C.

[0237] The first set has a first light-receiving region 55a and a second light-receiving region 56a aligned in a first direction E that intersects with the rotation direction C of the rotating plate 20a. The second set has a third light-receiving region 57a ​​and a fourth light-receiving region 58a aligned in a second direction F that intersects with the rotation direction C, and is provided alongside the first set in the rotation direction C.

[0238] The end of the first light-receiving region 55a on the side of the second light-receiving region 56a, the end of the second light-receiving region 56a on the side of the first light-receiving region 55a, the end of the third light-receiving region 57a ​​on the side of the fourth light-receiving region 58a, and the end of the fourth light-receiving region 58a on the side of the third light-receiving region 57a ​​are all straight lines along the tangential direction of the rotation direction C.

[0239] Furthermore, the end of the first light-receiving region 55a opposite to the second light-receiving region 56a, the end of the second light-receiving region 56a opposite to the first light-receiving region 55a, the end of the third light-receiving region 57a ​​opposite to the fourth light-receiving region 58a, and the end of the fourth light-receiving region 58a opposite to the third light-receiving region 57a ​​are all straight lines along the tangential direction of the rotation direction C.

[0240] The encoder according to the third embodiment has been described above.

[0241] In the encoder according to the third embodiment, the end of the first light-receiving area 55a on the side of the second light-receiving area 56a, the end of the second light-receiving area 56a on the side of the first light-receiving area 55a, the end of the third light-receiving area 57a on the side of the fourth light-receiving area 58a, and the end of the fourth light-receiving area 58a on the side of the third light-receiving area 57a are all straight lines along the tangential direction of the rotation direction C.

[0242] According to this, the decrease in the amount of light received by the first light-receiving area 55a, the second light-receiving area 56a, the third light-receiving area 57a, and the fourth light-receiving area 58a can be suppressed, so the eccentricity of the rotating plate 20a relative to the motor 1 can be detected with even greater accuracy.

[0243] (Fourth embodiment) Figure 16 is a schematic diagram of the rotating plate 20b of the encoder according to the fourth embodiment, viewed from the axial direction. Figure 17 is a schematic diagram of the light-emitting section 40b and light-receiving section 50b of the encoder in Figure 16, viewed from the axial direction. The configuration of the encoder according to the fourth embodiment will be described with reference to Figures 16 and 17. In the fourth embodiment, the same reference numerals are used for the same components and functions as in the second embodiment, and detailed explanations of these components and functions are omitted. In the following, the differences from the encoder 10a according to the second embodiment will be mainly described.

[0244] Note that in Figure 16, only half of the rotating plate 20b is shown to avoid making the drawing too complex.

[0245] As shown in Figure 16, the encoder according to the fourth embodiment includes a rotating plate 20b that is different from the rotating plate 20. Also, as shown in Figure 17, the encoder according to the fourth embodiment includes an output unit 40b that is different from the output unit 40 and a light receiving unit 50b that is different from the light receiving unit 50. The encoder according to the fourth embodiment differs from the encoder 10a in these respects.

[0246] As shown in Figure 16, the rotating plate 20b has a main body 21, an absolute pattern 22b, an incremental pattern 24b, and an annular region 26b.

[0247] The annular region 26b is an annular region provided so as to surround the axis of rotation A and reflects the light emitted from the emission section 40b. The annular region 26b reflects the light emitted from the emission section 40b toward the light receiving section 50b. The annular region 26b is provided on the main surface of the main body 21 on the emission section 40b side. The direction in which the axis B of the annular region 26b extends coincides with the axial direction. For example, the annular region 26b is composed of continuously arranged annular reflective sections that reflect the light emitted from the emission section 40b toward the light receiving section 50b.

[0248] The annular region 26b is positioned inward of the absolute pattern 22b and the incremental pattern 24b in the radial direction centered on the axis B. In other words, of the absolute pattern 22b, the incremental pattern 24b, and the annular region 26b, the annular region 26b is positioned furthest inward in that radial direction.

[0249] As shown in Figure 17, the emission unit 40b emits light. Specifically, the emission unit 40b emits light toward the rotating plate 20b. More specifically, the emission unit 40b emits light toward the absolute pattern 22b, the incremental pattern 24b, and the annular region 26b. The emission unit 40b is provided on the main surface of the substrate 30 on the rotating plate 20b side.

[0250] The light-receiving unit 50b receives light emitted from the emission unit 40b and passing through the annular region 26b. The light-receiving unit 50b has a first absolute light-receiving region 51b, a second absolute light-receiving region 52b, a first incremental light-receiving region 53b, a second incremental light-receiving region 54b, a first set, and a second set.

[0251] The first absolute light-receiving region 51b and the second absolute light-receiving region 52b each receive light emitted from the emission section 40b and that has passed through the absolute pattern 22b.

[0252] The first incremental light-receiving area 53b and the second incremental light-receiving area 54b each receive light emitted from the emission section 40b and that has passed through the incremental pattern 24b.

[0253] The first set has a first light-receiving region 55b and a second light-receiving region 56b aligned in a first direction E that intersects with the rotation direction C of the rotating plate 20b. The second set has a third light-receiving region 57b and a fourth light-receiving region 58b aligned in a second direction F that intersects with the rotation direction C, and is provided alongside the first set in the rotation direction C.

[0254] Each of the first and second sets is positioned inward from the emission section 40b in the radial direction centered on the rotation axis A. In other words, in the radial direction centered on the rotation axis A, each of the first light-receiving area 55b, the second light-receiving area 56b, the third light-receiving area 57b, and the fourth light-receiving area 58b is positioned inward from the emission section 40b.

[0255] The end of the first light-receiving region 55b on the side of the second light-receiving region 56b, the end of the second light-receiving region 56b on the side of the first light-receiving region 55b, the end of the third light-receiving region 57b on the side of the fourth light-receiving region 58b, and the end of the fourth light-receiving region 58b on the side of the third light-receiving region 57b are all curved in the direction of rotation C.

[0256] Furthermore, the end of the first light-receiving region 55b opposite to the second light-receiving region 56b, the end of the second light-receiving region 56b opposite to the first light-receiving region 55b, the end of the third light-receiving region 57b opposite to the fourth light-receiving region 58b, and the end of the fourth light-receiving region 58b opposite to the third light-receiving region 57b are all curved along the rotational direction C.

[0257] Each of the first light-receiving region 55b, the second light-receiving region 56b, the third light-receiving region 57b, and the fourth light-receiving region 58b is arc-shaped along the rotation direction C.

[0258] The first direction E is the direction that coincides with the radial direction centered on the axis of rotation A, and the second direction F is the direction that coincides with the radial direction centered on the axis of rotation A and intersects with the first direction E.

[0259] The first light-receiving region 55b and the third light-receiving region 57b are adjacent in the rotation direction C, and the second light-receiving region 56b and the fourth light-receiving region 58b are adjacent in the rotation direction C.

[0260] The encoder according to the fourth embodiment has been described above.

[0261] In the encoder according to the fourth embodiment, the first set and the second set are each arranged inward from the ejection section 40b in the radial direction with respect to the rotation axis A.

[0262] According to this, the light received by the first light-receiving area 55b, the second light-receiving area 56b, the third light-receiving area 57b, and the fourth light-receiving area 58b can be more easily curved, so the eccentricity of the rotating plate 20b relative to the motor 1 can be detected with even greater precision.

[0263] Furthermore, in the encoder according to the fourth embodiment, the end of the first light-receiving area 55b on the second light-receiving area 56b side, the end of the second light-receiving area 56b on the first light-receiving area 55b side, the end of the third light-receiving area 57b on the fourth light-receiving area 58b side, and the end of the fourth light-receiving area 58b on the third light-receiving area 57b side are all curved in line with the rotation direction C.

[0264] According to this, the decrease in the amount of light received by the first light-receiving area 55b, the second light-receiving area 56b, the third light-receiving area 57b, and the fourth light-receiving area 58b can be suppressed, so the eccentricity of the rotating plate 20b relative to the motor 1 can be detected with even greater accuracy.

[0265] Furthermore, in the encoder according to the fourth embodiment, the first direction E is a direction that coincides with the radial direction centered on the rotation axis A, and the second direction F is a direction that coincides with the radial direction centered on the rotation axis A and intersects with the first direction E.

[0266] Since the decrease in the amount of light received by the first light-receiving area 55b, the second light-receiving area 56b, the third light-receiving area 57b, and the fourth light-receiving area 58b can be further suppressed, the eccentricity of the rotating plate 20b relative to the motor 1 can be detected with even greater accuracy.

[0267] (Fifth embodiment) FIG. 18 is a schematic view of the light emitting portion 40c and the light receiving portion 50c of the encoder according to the fifth embodiment, as viewed in the axial direction. Referring to FIG. 18, the configuration of the encoder according to the fifth embodiment will be described. In the fifth embodiment, the same components and functions as those in the second embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. Hereinafter, the differences from the encoder 10a according to the second embodiment will be mainly described.

[0268] As shown in FIG. 18, the encoder according to the fifth embodiment is mainly different from the encoder 10a in that it includes a rotating plate (not shown) different from the rotating plate 20, a light emitting portion 40c different from the light emitting portion 40, and a light receiving portion 50c different from the light receiving portion 50.

[0269] The light emitting portion 40c emits light. Specifically, the light emitting portion 40c emits light toward the rotating plate. More specifically, the light emitting portion 40c emits light toward an annular region (not shown) of the rotating plate. The light emitting portion 40c is provided on the main surface of the substrate 30 on the rotating plate side.

[0270] The light receiving portion 50c receives light such as light emitted from the light emitting portion 40c and passing through the annular region of the rotating plate of the encoder according to the fifth embodiment. The light receiving portion 50c has a first absolute light receiving region 51c, a second absolute light receiving region 52c, a first incremental light receiving region 53c, a second incremental light receiving region 54c, a first set, and a second set.

[0271] Each of the first absolute light receiving region 51c and the second absolute light receiving region 52c receives light emitted from the light emitting portion 40c and passing through the absolute pattern of the rotating plate.

[0272] Each of the first incremental light receiving region 53c and the second incremental light receiving region 54c receives light emitted from the light emitting portion 40c and passing through the incremental pattern of the rotating plate.

[0273] The first set has a first light-receiving region 55c and a second light-receiving region 56c aligned in a first direction E that intersects the rotation direction C of the rotating plate. The second set has a third light-receiving region 57c and a fourth light-receiving region 58c aligned in a second direction F that intersects the rotation direction C, and is provided alongside the first set in the rotation direction C.

[0274] The first and second sets are positioned with a 90-degree phase difference in the rotational direction C. In other words, the second set is positioned 90 degrees away from the first set in the rotational direction C.

[0275] The encoder according to the fifth embodiment has been described above.

[0276] (Sixth Embodiment) Figure 19 is an explanatory diagram illustrating the relationship between the dimensions of the first light-receiving area 55d and the second light-receiving area 56d and the dimensions of the light irradiated onto the first light-receiving area 55d and the second light-receiving area 56d in the encoder according to the sixth embodiment. The configuration of the encoder according to the sixth embodiment will be described with reference to Figure 19. In the sixth embodiment, the same reference numerals are used for the same components and functions as in the second embodiment, and detailed explanations of these components and functions are omitted. In the following, the differences from the encoder 10a according to the second embodiment will be mainly described.

[0277] As shown in Figure 19, in this embodiment, the emission unit 40d has a surface light source, and the dimension between the annular region 26d in the axial direction to which the rotation axis A extends and the emission unit 40d is h1, the dimension between the annular region 26d in the axial direction to which the rotation axis A extends and the first light receiving region 55d and the second light receiving region 56d is h2, the dimension from the end of the first light receiving region 55d opposite to the second light receiving region 56d in the first direction E is L, and the annular region 2 in the first direction E Let W1 be the dimension of 6d, W2 be the dimension of the light emitted from the surface light source, passing through the annular region 26d and illuminating the first light-receiving region 55d and the second light-receiving region 56d in the first direction E, and D be the dimension of the light-emitting opening of the surface light source in the first direction E. Then, it is desirable to design L such that W2 = ((h2 / h1) + 1) × W1 + D and W2 / L < 1, and that even if the reflected light on the light-receiving surface moves due to the maximum correctable eccentricity, the reflected light does not extend beyond the light-receiving region (first light-receiving region 55d and second light-receiving region 56d). The same relationship is satisfied for the third and fourth light-receiving regions.

[0278] The encoder according to the sixth embodiment has been described above.

[0279] In the encoder according to the sixth embodiment, the emission unit 40d has a surface light source, the dimension between the annular region 26d in the axial direction to which the rotation axis A extends and the emission unit 40d is h1, the dimension between the annular region 26d in the axial direction to which the rotation axis A extends and the first light receiving region 55d and the second light receiving region 56d is h2, and the second light receiving region 56d is located from the end of the first light receiving region 55d opposite to the second light receiving region 56d in the first direction E Let L be the dimension from the first light-receiving region 55d to the end opposite to it, let W1 be the dimension of the annular region 26d in the first direction E, let W2 be the dimension of the light emitted from the surface light source that passes through the annular region 26d and irradiates the first light-receiving region 55d and the second light-receiving region 56d in the first direction E, and let D be the dimension of the light-emitting opening of the surface light source in the first direction E. Then, W2 = ((h2 / h1) + 1) × W1 + D and W2 / L < 1 are satisfied.

[0280] According to this, when the rotating plate is eccentric with respect to the motor 1, the position of the light received by the first light-receiving area 55d and the second light-receiving area 56d can be appropriately changed as the rotating plate rotates, so that the eccentricity of the rotating plate with respect to the motor 1 can be detected with even greater accuracy.

[0281] (Other embodiments, etc.) As described above, embodiments have been explained as examples of the technology disclosed in this application. However, the technology disclosed herein is not limited to these embodiments, and can be applied to embodiments or modified versions that are changed, replaced, added, omitted, etc., as appropriate, as long as they do not deviate from the spirit of this disclosure.

[0282] In the embodiments described above, the case in which the annular regions 26 to 26d reflect light was explained, but the invention is not limited to this. For example, the annular regions may transmit light emitted from the emission portion toward the light receiving portion.

[0283] In the above embodiment, the display unit 80 may display an image showing the total motor operating time. For example, the image may be color-coded from blue to red depending on the length of the total motor operating time, such as when the total motor operating time is less than 10 hours, 10 hours or more but less than 100 hours, 100 hours or more but less than 1000 hours, and 1000 hours or more but less than 3000 hours. This makes it possible to display the degree of wear on the motor bearings in a way that a person can understand. In this case, a third and subsequent setting time may be provided that is different from the first and second setting times.

[0284] In the above embodiment, a first threshold, a second threshold, and a third threshold are provided, but these thresholds may be set according to the set time. In other words, a fourth threshold and subsequent thresholds may be provided.

[0285] In the above embodiments, each component may be implemented by dedicated hardware or by executing a software program suitable for each component. Each component may also be implemented by a program execution unit such as a CPU (Central Processing Unit) or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory. Here, the software that implements each of the above embodiments is a computer program that causes a computer to execute each step of the flowchart shown in Figures 12A and 12B, respectively.

[0286] The following cases are also included in this disclosure.

[0287] (1) The at least one device described above is specifically a computer system consisting of a microprocessor, ROM, RAM, hard disk unit, display unit, keyboard, mouse, etc. A computer program is stored in the RAM or hard disk unit. The at least one device described above achieves its function by the operation of the microprocessor in accordance with the computer program. Here, the computer program is composed of a combination of multiple instruction codes that indicate instructions to the computer in order to achieve a predetermined function.

[0288] (2) Some or all of the components constituting at least one of the above-described devices may be made up of a single system LSI (Large Scale Integration). The system LSI is a multi-functional LSI manufactured by integrating multiple components onto a single chip, and specifically, it is a computer system comprising a microprocessor, ROM, RAM, etc. The RAM stores a computer program. The system LSI achieves its function by operating the microprocessor in accordance with the computer program.

[0289] (3) Some or all of the components constituting at least one of the above devices may be composed of an IC card or a single module detachable from the device. The IC card or module is a computer system composed of a microprocessor, ROM, RAM, etc. The IC card or module may include the above-mentioned multifunctional LSI. When the microprocessor operates according to a computer program, the IC card or module achieves its function. This IC card or this module may have tamper resistance.

[0290] (4) The present disclosure may be the method shown above. It may also be a computer program for realizing these methods by a computer, or a digital signal composed of a computer program.

[0291] Further, the present disclosure may be a computer program or a digital signal recorded on a computer-readable recording medium, such as a flexible disk, a hard disk, a CD (Compact Disc)-ROM, a DVD, a DVD-ROM, a DVD-RAM, a BD (Blu-ray (registered trademark) Disc), a semiconductor memory, etc. It may also be a digital signal recorded on these recording media.

[0292] Further, the present disclosure may be a computer program or a digital signal transmitted via a telecommunication line, a wireless or wired communication line, a network represented by the Internet, data broadcasting, etc.

[0293] Also, it may be implemented by another independent computer system by recording and transferring the program or digital signal to a recording medium, or by transferring the program or digital signal via a network or the like.

[0294] The following describes the features of the encoder and control system described based on the above embodiment.

[0295] <Technology 1> A light-emitting section and A rotating plate having an annular region that surrounds the axis of rotation of the rotating plate and reflects or transmits light emitted from the emission portion, A light receiving unit that receives light emitted from the emission unit and that has passed through the annular region, A signal processing circuit that processes the signal from the light receiving unit, The system includes a determination circuit that determines an abnormality based on the output result processed by the signal processing circuit, The light-receiving unit comprises a first set having a first light-receiving region and a second light-receiving region aligned in a first direction intersecting the rotation direction of the rotating plate, and a second set having a third light-receiving region and a fourth light-receiving region aligned in a second direction intersecting the rotation direction, and provided alongside the first set in the rotation direction. Encoder.

[0296] <Technology 2> When the signal value corresponding to the light received by the first light-receiving region is A1, the signal value corresponding to the light received by the second light-receiving region is A2, the signal value corresponding to the light received by the third light-receiving region is B1, and the signal value corresponding to the light received by the fourth light-receiving region is B2, the signal processing circuit processes the following signals indicating the value of X and the signal indicating the value of Y, and the determination circuit monitors whether the changes in the DC component of the signal indicating the value of X and the DC component of the signal indicating the value of Y exceed a predetermined threshold. The values ​​of X and Y satisfy the following relationship: X = (A1 + B2) - (B1 + A2) Y=(A1+B1)-(A2+B2) The encoder described in Technology 1.

[0297] <Technology 3> Different thresholds are set for the DC component of the signal representing the value of X and the DC component of the signal representing the value of Y. The encoder described in Technical 2.

[0298] <Technology 4> The predetermined threshold includes a first threshold, An encoder as described in either Technology 2 or 3, The system includes a display unit that displays an abnormality when the DC component of the signal indicating the value of X and the DC component of the signal indicating the value of Y exceed the first threshold. Control system.

[0299] <Technology 5> The predetermined threshold includes a second threshold, When the total operating time of the motor equipped with the encoder is less than or equal to the first set time, and the DC component of the signal indicating the value of X or the DC component of the signal indicating the value of Y exceeds the second threshold, the display unit indicates that the rotation shaft load is excessive. The control system described in Technical 4.

[0300] <Technology 6> The aforementioned predetermined threshold includes a third threshold, When the total operating time of the motor equipped with the encoder exceeds the second set time, and the DC component of the signal indicating the value of X and the DC component of the signal indicating the value of Y exceed the third threshold, the display unit indicates that there is a bearing failure. A control system as described in Technology 4 or 5.

[0301] <Technology 7> The aforementioned determination circuit includes a function to rotate the motor's rotation shaft by one or more revolutions in order to determine an abnormality based on the output of the signal processing circuit. A control system as described in any one of the technologies 4 to 6.

[0302] <Technology 8> It features a dedicated operating mode that rotates the motor's axis at least one full turn to detect abnormalities. The control system described in Technical 7.

[0303] <Technology 9> The system includes a function to determine the tilt amount and direction of the rotation axis based on the sign and absolute value of the DC offset of the signal indicating the X value and the signal indicating the Y value, respectively, obtained by rotating the motor's rotation axis once. A control system as described in Technical 7 or 8.

[0304] <Technology 10> The system includes a function to determine the tilt of the axis of the rotating shaft from the sign and absolute value of the DC offset of the signal indicating the value of X obtained by rotating the motor's rotating shaft once, and to correct the angular error caused by the tilt. A control system as described in any one of the technologies 4 through 9.

[0305] <Technology 11> The sensor in the light-receiving unit is used to detect an abnormality. The encoder according to any one of claims 1 to 3.

[0306] <Technology 12> The device further includes an output unit that outputs a signal with the following Y values, where A1 is the signal value corresponding to the light received by the first light-receiving region, A2 is the signal value corresponding to the light received by the second light-receiving region, B1 is the signal value corresponding to the light received by the third light-receiving region, and B2 is the signal value corresponding to the light received by the fourth light-receiving region. Y=(A1+B1)-(A2+B2) An encoder as described in one of the following technologies: 1 through 3, or 11.

[0307] <Technology 13> The output unit outputs a signal indicating the following Q values: Q = A1 + B1 + A2 + B2 The encoder described in Technical 12.

[0308] <Technology 14> The output unit further outputs a signal indicating the value of X, a signal indicating the value of X1, and a signal indicating the value of Y1. X = (A1 + B2) - (B1 + A2) X1 = X / Q Y1 = Y / Q The encoder described in Technical 13.

[0309] <Technology 15> The rotating plate has one or more patterns for detecting the rotation angle of the rotating plate. The light-receiving unit has one or more light-receiving regions that receive light emitted from the emission unit and that has passed through one or more patterns. The calculation unit further comprises a calculation unit that calculates the following value of P1, where P is the rotation angle of the rotating plate detected based on the light emitted from the emission unit and received by the one or more light receiving regions after passing through the one or more patterns, Δr is the eccentricity of the axis of the annular region with respect to the rotation axis, Φ is the eccentric phase of the axis with respect to the rotation axis, and r is the radius of the annular region. P1 = P + tan -1 (Δr × sinΦ / r) Alternatively, P1 = P - tan -1 (Δr × sinΦ / r) The output unit outputs a signal indicating the value of P1 calculated by the calculation unit. An encoder as described in any one of the technologies 12 to 14.

[0310] <Technology 16> By rotating the plate once using the motor, a signal indicating the value of Y is obtained. Based on the signal indicating the acquired Y value, the angular error of the rotating plate is acquired. The system includes a function to correct the position signal of the encoder indicating the position of the rotating plate based on the acquired angular error. The encoder described in Technical 12.

[0311] <Technology 17> The signal representing the acquired Y value is fitted, Based on the signal indicating the fitted Y value, an angle error correction function is generated to determine the angle error of the rotating plate. The system includes a function to correct the position signal of the encoder indicating the position of the rotating plate by setting an angle error correction table based on the generated angle error correction function. The encoder described in Technical 16.

[0312] <Technology 18> The output unit further outputs a signal indicating the following value of X: X = (A1 + B2) - (B1 + A2) The motor rotates the rotating plate once to obtain a signal indicating the value of X, The DC offset γ0 of the signal representing the acquired value of X is determined, It has a function to store the γ0 of the signal indicating the acquired value of X, The encoder described in Technical 17.

[0313] <Technology 19> After a certain period of time has elapsed since storing γ0, the motor rotates the plate once to obtain a signal indicating the value of X, and γ1, which is the DC offset of the signal indicating the value of X, is determined. The system includes a function to determine whether or not there is an abnormality based on whether or not γ0 and γ1 match. The encoder described in Technical 18.

[0314] <Technology 20> The first set and the second set are provided with the ejection portion sandwiched between them in the rotational direction, An encoder as described in one of the following technical specifications: 1, 12 through 19.

[0315] <Technology 21> Each of the first set and the second set is provided inward from the ejection portion in the radial direction with respect to the rotation axis, An encoder as described in one of the following technical specifications: 1, 12 through 19.

[0316] <Technology 22> Each of the ends of the first light-receiving region on the second light-receiving region side, the end of the second light-receiving region on the first light-receiving region side, the end of the third light-receiving region on the fourth light-receiving region side, and the end of the fourth light-receiving region on the third light-receiving region side are curved along the direction of rotation. An encoder as described in any one of the following technical specifications: 1, 12 to 21.

[0317] <Technology 23> Each of the ends of the first light-receiving region on the second light-receiving region side, the end of the second light-receiving region on the first light-receiving region side, the end of the third light-receiving region on the fourth light-receiving region side, and the end of the fourth light-receiving region on the third light-receiving region side are in a straight line along the tangential direction of the rotational direction. An encoder as described in any one of the following technical specifications: 1, 12 to 22.

[0318] <Technology 24> Each of the first and second directions is a direction parallel to a straight line perpendicular to the axis of rotation, The first set and the second set are arranged symmetrically with respect to the straight line as the axis of symmetry. An encoder as described in one of the following technologies, 1, 12 to 23.

[0319] <Technology 25> The first direction is the direction that coincides with the radial direction centered on the axis of rotation, The second direction is a direction that coincides with the radial direction centered on the axis of rotation and intersects with the first direction. An encoder as described in one of the following technologies, 1, 12 to 23.

[0320] <Technology 26> The distance from the end of the first light-receiving region opposite to the second light-receiving region in the first direction to the end of the second light-receiving region opposite to the first light-receiving region is greater than the distance in the first direction of the light emitted from the emission portion and irradiated onto the first light-receiving region and the second light-receiving region via the annular region. The distance in the second direction from the end of the third light-receiving region opposite to the fourth light-receiving region to the end of the fourth light-receiving region opposite to the third light-receiving region is greater than the distance in the second direction of the light emitted from the emission portion and irradiated onto the third and fourth light-receiving regions via the annular region. An encoder as described in any one of the following technical specifications: 1, 12 to 25.

[0321] <Technology 27> The emission unit has a point light source, Let h1 be the dimension between the annular region and the emission portion in the axial direction in which the rotation axis extends, let h2 be the dimension between the annular region and the first light-receiving region and the second light-receiving region in the axial direction in which the rotation axis extends, let L be the dimension from the end of the first light-receiving region opposite to the second light-receiving region in the first direction, let W1 be the dimension of the annular region in the first direction, and let W2 be the dimension in the first direction of the light emitted from the point light source and irradiated onto the first light-receiving region and the second light-receiving region via the annular region, then W2 = (h2 / h1) × W1 and W2 / L < 1. The encoder described in Technical 26.

[0322] <Technology 28> The emission unit has a surface light source, Let h1 be the dimension between the annular region and the emission part in the axial direction in which the rotation axis extends, let h2 be the dimension between the annular region and the first light-receiving region and the second light-receiving region in the axial direction in which the rotation axis extends, let L be the dimension from the end of the first light-receiving region opposite to the second light-receiving region in the first direction, let W1 be the dimension of the annular region in the first direction, let W2 be the dimension of the light emitted from the surface light source and irradiated onto the first light-receiving region and the second light-receiving region via the annular region in the first direction, and let D be the dimension of the light emission opening of the surface light source in the first direction, then W2 = ((h2 / h1) + 1) × W1 + D and W2 / L < 1. The encoder described in Technical 26. [Industrial applicability]

[0323] The encoder described herein can be used for detecting the rotation of the rotating shaft of a motor that rotates a load. [Explanation of Symbols]

[0324] 3. Control System 10,10a encoder 20, 20a, 20b Rotating plate 21 Main unit 22. First Absolute Pattern 22a, 22b Absolute Pattern 23. Second Absolute Pattern 24. First Incremental Pattern 24a, 24b Incremental pattern 25. Second Incremental Pattern 26,26a,26b,26d Circular region 30 circuit boards 40,40a,40b,40c,40d Output part 50,50a,50b,50c Light receiving section 51, 51a, 51b, 51c First absolute photoreceiving region 52, 52a, 52b, 52c Second absolute photoreceiving region 53, 53a, 53b, 53c First incremental light-receiving region 54, 54a, 54b, 54c Second incremental light-receiving region 55,55a,55b,55c,55d 1st light receiving area 56,56a,56b,56c,56d 2nd light receiving area 57,57a,57b,57c 3rd light receiving area 58,58a,58b,58c 4th light receiving area 60 Output section 61 Signal Processing Circuits 62 Judgment circuit 70 Calculation Unit 80 Display section

Claims

1. A light-emitting section and A rotating plate having an annular region that surrounds the axis of rotation of the rotating plate and reflects or transmits light emitted from the emission portion, A light receiving unit that receives light emitted from the emission unit and that has passed through the annular region, A signal processing circuit that processes the signal from the light receiving unit, The system includes a determination circuit that determines an abnormality based on the output result processed by the signal processing circuit, The light-receiving unit comprises a first set having a first light-receiving region and a second light-receiving region aligned in a first direction intersecting the rotation direction of the rotating plate, and a second set having a third light-receiving region and a fourth light-receiving region aligned in a second direction intersecting the rotation direction, and provided alongside the first set in the rotation direction. Encoder.

2. When the signal value corresponding to the light received by the first light-receiving region is A1, the signal value corresponding to the light received by the second light-receiving region is A2, the signal value corresponding to the light received by the third light-receiving region is B1, and the signal value corresponding to the light received by the fourth light-receiving region is B2, the signal processing circuit processes the following signals indicating the value of X and the signal indicating the value of Y, and the determination circuit monitors whether the changes in the DC component of the signal indicating the value of X and the DC component of the signal indicating the value of Y exceed a predetermined threshold, The values ​​of X and Y satisfy the following relationship: X=(A1+B2)-(B1+A2) Y=(A1+B1)-(A2+B2) The encoder according to claim 1.

3. Different predetermined thresholds are set for the DC component of the signal indicating the value of X and the DC component of the signal indicating the value of Y, respectively. The encoder according to claim 2.

4. The predetermined threshold includes a first threshold, The encoder according to claim 2, The system includes a display unit that displays an abnormality when the DC component of the signal indicating the value of X and the DC component of the signal indicating the value of Y exceed the first threshold. Control system.

5. The aforementioned predetermined threshold includes a second threshold, The encoder detects the rotation of an external motor for rotating the rotating plate, When the total operating time of the motor is less than or equal to the first set time, and the DC component of the signal indicating the value of X or the DC component of the signal indicating the value of Y exceeds the second threshold, the display unit indicates that the rotation shaft load is excessive. The control system according to claim 4.

6. The aforementioned predetermined threshold includes a third threshold, The encoder detects the rotation of an external motor for rotating the rotating plate, When the total operating time of the motor exceeds the second set time, and the DC component of the signal indicating the value of X and the DC component of the signal indicating the value of Y exceed the third threshold, the display unit indicates that there is a bearing failure. The control system according to claim 4.

7. The encoder detects the rotation of an external motor for rotating the rotating plate, The determination circuit includes a function to rotate the motor's rotation shaft by one or more revolutions in order to determine an abnormality based on the output of the signal processing circuit. The control system according to claim 4.

8. The motor is equipped with a dedicated operating mode that rotates the motor's rotating shaft at least once to detect abnormalities. The control system according to claim 7.

9. A function to determine the amount of inclination of the rotating shaft and the direction of inclination of the rotating shaft from the sign and absolute value of the DC offset of the signal indicating the value of X and the signal indicating the value of Y, respectively, obtained by rotating the rotating shaft of the motor once. The control system according to claim 7.

10. The encoder detects the rotation of an external motor for rotating the rotating plate, The system includes a function to determine the amount of inclination of the axis of rotation from the sign and absolute value of the DC offset of the signal indicating the value of X obtained by rotating the motor's rotation axis once, and to correct the angular error caused by the amount of inclination. The control system according to claim 4.

11. The sensor in the light-receiving unit is used to detect an abnormality. The encoder according to claim 1.

12. The device further includes an output unit that outputs a signal with the following Y values, where A1 is the signal value corresponding to the light received by the first light-receiving region, A2 is the signal value corresponding to the light received by the second light-receiving region, B1 is the signal value corresponding to the light received by the third light-receiving region, and B2 is the signal value corresponding to the light received by the fourth light-receiving region. Y=(A1+B1)-(A2+B2) The encoder according to claim 11.

13. The output unit outputs a signal showing the following Q values: Q=A1+B1+A2+B2 The encoder according to claim 12.

14. The output unit further outputs a signal indicating the value of X, a signal indicating the value of X1, and a signal indicating the value of Y1. X=(A1+B2)-(B1+A2) X1 = X / Q Y1 = Y / Q The encoder according to claim 13.

15. The rotating plate has one or more patterns for detecting the rotation angle of the rotating plate. The light-receiving unit has one or more light-receiving regions that receive light emitted from the emission unit and that has passed through one or more patterns. The calculation unit further comprises a calculation unit that calculates the following value of P1, where P is the rotation angle of the rotating plate detected based on the light emitted from the emission unit and received by the one or more light receiving regions after passing through the one or more patterns, Δr is the eccentricity of the axis of the annular region with respect to the rotation axis, Φ is the eccentric phase of the axis with respect to the rotation axis, and r is the radius of the annular region. P1=P+tan －１ (Δr×sinΦ / r) Alternatively, P1 = P - tan －１ (Δr×sinΦ / r) The output unit outputs a signal indicating the value of P1 calculated by the calculation unit. The encoder according to any one of claims 12 to 14.

16. The encoder detects the rotation of an external motor for rotating the rotating plate, By rotating the rotating plate once using the motor, a signal indicating the value of Y is obtained. Based on the signal indicating the acquired value of Y, the angular error of the rotating plate is acquired. The system includes a function to correct the position signal of the encoder indicating the position of the rotating plate based on the acquired angular error. The encoder according to claim 12.

17. The signal representing the acquired value of Y is fitted, Based on the signal indicating the fitted Y value, an angle error correction function is generated to determine the angle error of the rotating plate. The system includes a function to correct the position signal of the encoder indicating the position of the rotating plate by setting an angle error correction table based on the generated angle error correction function. The encoder according to claim 16.

18. The output unit further outputs a signal indicating the following value of X: X=(A1+B2)-(B1+A2) The motor rotates the rotating plate once to obtain a signal indicating the value of X, The DC offset γ0 of the signal indicating the acquired value of X is determined, It has a function to store the γ0 of the signal indicating the acquired value of X, The encoder according to claim 17.

19. After determining γ0, a certain period of time has elapsed, and the motor is used to rotate the rotating plate once to obtain a signal indicating the value of X, and the DC offset γ1 of the signal indicating the value of X is determined. The system includes a function to determine whether or not there is an abnormality based on whether or not γ0 and γ1 match. The encoder according to claim 18.

20. The first set and the second set are provided with the ejection part in the direction of rotation, The encoder according to any one of claims 1, 12 to 14.

21. Each of the first set and the second set is provided inward from the ejection portion in the radial direction with respect to the rotation axis, The encoder according to any one of claims 1, 12 to 14.

22. Each of the ends of the first light-receiving region on the second light-receiving region side, the end of the second light-receiving region on the first light-receiving region side, the end of the third light-receiving region on the fourth light-receiving region side, and the end of the fourth light-receiving region on the third light-receiving region side are curved along the direction of rotation. The encoder according to any one of claims 1, 12 to 14.

23. Each of the ends of the first light-receiving region on the second light-receiving region side, the end of the second light-receiving region on the first light-receiving region side, the end of the third light-receiving region on the fourth light-receiving region side, and the end of the fourth light-receiving region on the third light-receiving region side are in a straight line along the tangential direction of the rotational direction. The encoder according to any one of claims 1, 12 to 14.

24. Each of the first and second directions is a direction parallel to a straight line perpendicular to the axis of rotation, The first set and the second set are arranged symmetrically with respect to the straight line as the axis of symmetry. The encoder according to any one of claims 1, 12 to 14.

25. The first direction is the direction that coincides with the radial direction centered on the axis of rotation, The second direction is a direction that coincides with the radial direction centered on the axis of rotation and intersects with the first direction. The encoder according to any one of claims 1, 12 to 14.

26. The distance from the end of the first light-receiving region opposite to the second light-receiving region in the first direction to the end of the second light-receiving region opposite to the first light-receiving region is greater than the distance in the first direction of the light emitted from the emission unit and irradiated onto the first light-receiving region and the second light-receiving region via the annular region. The distance in the second direction from the end of the third light-receiving region opposite to the fourth light-receiving region to the end of the fourth light-receiving region opposite to the third light-receiving region is greater than the distance in the second direction of the light emitted from the emission section and irradiated onto the third and fourth light-receiving regions via the annular region. The encoder according to any one of claims 1, 12 to 14.

27. The emission unit has a point light source, Let h1 be the dimension between the annular region and the emission portion in the axial direction in which the rotation axis extends, let h2 be the dimension between the annular region and the first light-receiving region and the second light-receiving region in the axial direction in which the rotation axis extends, let L be the dimension from the end of the first light-receiving region opposite to the second light-receiving region in the first direction, let W1 be the dimension of the annular region in the first direction, and let W2 be the dimension in the first direction of the light emitted from the point light source and irradiated onto the first light-receiving region and the second light-receiving region via the annular region, then W2 = (h2 / h1) × W1 and W2 / L < 1. The encoder according to claim 26.

28. The emission unit has a surface light source, Let h1 be the dimension between the annular region and the emission part in the axial direction in which the rotation axis extends, let h2 be the dimension between the annular region and the first light-receiving region and the second light-receiving region in the axial direction in which the rotation axis extends, let L be the dimension from the end of the first light-receiving region opposite to the second light-receiving region in the first direction, let W1 be the dimension of the annular region in the first direction, let W2 be the dimension of the light emitted from the surface light source and irradiated onto the first light-receiving region and the second light-receiving region via the annular region in the first direction, and let D be the dimension of the light emission opening of the surface light source in the first direction, then W2 = ((h2 / h1) + 1) × W1 + D and W2 / L < 1. The encoder according to claim 26.

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