Angle Sensor

Abstract

Provided is an angle sensor with which it is possible to analyze the relative positional relationship between objects relevant to detection of an angle while practically applying a known angle detection function. This angle sensor (24) comprises: a measurement unit (44) that measures the strength of magnetism generated by a magnet (32) and that acquires a measurement signal indicating the strength of the magnetism; a selection unit (50) that selectively executes a measurement mode, in which an output signal indicating the relative rotation angle between a first object (12) and a second object (14) is generated from the acquired measurement signal, and an inspection mode, in which an output signal indicating the strength of the magnetism is generated from the measurement signal; and an output unit (62) that outputs the output signal generated according to the mode selection.

Description

[Technical field]

[0001] The present invention relates to an angle sensor. [Background technology]

[0002] Magnetic angle sensors are known that detect the angle of a rotating body, such as a motor shaft, by attaching a magnet to the rotating body and measuring the magnetic strength emitted from the magnet using a Hall element (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-103502 A [Patent Document 2] JP 2019-207204 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the position of the rotating body or the angle sensor is shifted for some reason, the relative positional relationship between the magnet and the Hall element may change. If an attempt is made to detect the angle under such circumstances, the accuracy of the angle detection may decrease, or the angle may not be detected at all. As a countermeasure, for example, it is conceivable to provide a detection mechanism for detecting the change in the relative position between the rotating body and the angle sensor. However, the component cost of the angle sensor increases with the addition of the detection mechanism.

[0005] The present invention has been made in consideration of these problems, and its purpose is to provide an angle sensor that can analyze the relative positional relationship between objects involved in angle detection while utilizing existing angle detection functions. [Means for solving the problem]

[0006] In order to solve the above problem, the angle sensor in a first aspect of the present invention is a sensor fixed to a second object that is rotatable relative to a first object, and is provided with a measurement unit that is spaced apart from a magnet built into or external to the first object and measures the magnetic strength emitted by the magnet to obtain a measurement signal indicating the magnetic strength, a selection unit that selectively executes a measurement mode that generates an output signal indicating the relative rotation angle between the first object and the second object from the measurement signal obtained by measurement by the measurement unit, and an inspection mode that generates an output signal indicating the magnetic strength from the measurement signal, and an output unit that outputs the output signal generated in accordance with the mode selection by the selection unit.

[0007] In the angle sensor of the second aspect of the present invention, the selection unit starts the inspection mode in response to a supply of power from an external device, and switches from the inspection mode to the measurement mode when the magnetic strength measured or the measurement signal obtained during execution of the inspection mode is within a predetermined range.

[0008] In the angle sensor of the third aspect of the present invention, if the magnetic strength measured or the measurement signal obtained during execution of the inspection mode is not within a predetermined range, the selection unit switches from the inspection mode to a notification mode in which an output signal having a different signal level than in the measurement mode is generated.

[0009] In the angle sensor according to the fourth aspect of the present invention, the first object and the second object are arranged coaxially along the vertical direction. Effect of the Invention

[0010] According to the present invention, it is possible to analyze the relative positional relationship between objects related to angle detection while utilizing an existing angle detection function. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic perspective view of a hydraulic rotary joint incorporating an angle sensor according to an embodiment of the present invention; [Diagram 2] FIG. 4 is a side view illustrating a schematic diagram of a relative positional relationship between an angle sensor and a magnet. [Diagram 3] 3 is a diagram showing an example of a circuit configuration of the sensor substrate of FIG. 2. [Figure 4] FIG. 4 is a functional block diagram of the DSP shown in FIG. [Diagram 5] FIG. 2 is a diagram showing an example of a correspondence relationship between magnetic flux density and voltage. [Figure 6] 5 is a flowchart showing an example of an operation of the DSP of FIG. 4. [Figure 7] 4 is a time chart showing an example of a voltage waveform in a normal state. [Figure 8] 4 is a time chart showing an example of a voltage waveform during an abnormality. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components and steps in each drawing are denoted by the same reference numerals as much as possible, and duplicated description will be omitted.

[0013] <Overall composition> Fig. 1 is a schematic perspective view of a hydraulic rotary joint 10 incorporating an angle sensor 24 according to an embodiment of the present invention. Fig. 2 is a side view showing a schematic diagram of the relative positional relationship between the angle sensor 24 and a magnet 32.

[0014] The hydraulic rotary joint 10 in Fig. 1 is a hydraulic device mounted on a vehicle that utilizes hydraulic pressure. Examples of the vehicle include an excavator, a mini excavator, a crawler crane, and aerial work vehicles. The roughly cylindrical hydraulic rotary joint 10 is basically composed of a main body 12 and a rotating part 14.

[0015] The main body 12 is fixed to an undercarriage (not shown) of the vehicle via a fixing plate 16 that protrudes horizontally from the bottom. The rotating part 14 is connected to an upper rotating body (not shown) of the vehicle via a pin 18 that protrudes horizontally from the side. A plurality of input / output ports 20 are provided on the peripheral surfaces of the main body 12 and the rotating part 14. In other words, the hydraulic rotary joint 10 constitutes a part of a hydraulic circuit for hydraulic control of the vehicle.

[0016] A swing motor 22 for swinging the upper swing body is provided outside the hydraulic rotary joint 10. Drive of the swing motor 22 allows the rotating part 14 to rotate clockwise or counterclockwise along the swing direction R relative to the main body part 12. When the vehicle is in a horizontal state, the axial directions of the main body part 12 and the rotating part 14 approximately coincide with the vertical direction (i.e., the direction in which gravity acts). In addition, a cable 26 is connected to the center of the upper surface of the rotating part 14 via an angle sensor 24.

[0017] As shown in Fig. 2, the fixed member 30 is a member fixed to the inner wall of the main body 12. A cylindrical or disk-shaped magnet 32 ​​is fixed to the upper surface of the fixed member 30. The magnet 32 ​​may be either a permanent magnet or an electromagnet. Meanwhile, the angle sensor 24 includes a cylindrical housing 34 having a flange on the rear end side, and a sensor board 36 provided at a position covering the opening on the tip side of the housing 34. When the angle sensor 24 is fixed to the rotating unit 14, the magnet 32 ​​and the sensor board 36 face each other while being separated from each other by a certain gap G.

[0018] The angle sensor 24 and the rotating part 14 rotate together, and thus the measured value of the magnetism generated by the magnet 32 ​​changes. This allows the angle sensor 24 to detect the relative rotation angle between the main body 12 (corresponding to the "first object") and the rotating part 14 (corresponding to the "second object"), which are provided coaxially. Note that in the examples of Figs. 1 and 2, the first object is fixed and the second object is rotatably provided, but this configuration is not limited as long as the rotation angle can be changed relatively. Specifically, [1] the second object may be fixed and the first object may be rotatably provided, or [2] the first object and the second object may be independently rotatably provided.

[0019] <Circuit configuration of sensor board 36> Fig. 3 is a diagram showing an example of a circuit configuration of the sensor substrate 36 of Fig. 2. On the sensor substrate 36, a logic IC (Integrated Circuit) 40, a crystal oscillator 42, a magnetic sensor IC 44 (corresponding to a "measurement unit"), a digital signal processor (hereinafter, DSP 46), and an amplifier 48 are provided.

[0020] The logic IC 40 is an integrated circuit for converting a logic level (here, Vcc) from 5.0 V to 3.3 V. Since the angle sensor 24 itself does not have a power supply, the driving power of the sensor board 36 is supplied from a higher-level device (not shown) via a cable 26 (FIG. 1).

[0021] The crystal oscillator 42 is a passive element used to generate oscillations with high frequency accuracy by utilizing the piezoelectric effect of crystal. A clock signal used for processing by the DSP 46 is generated based on this oscillation.

[0022] The magnetic sensor IC 44 is an integrated circuit incorporating a Hall element that detects magnetic strength. Specifically, the magnetic sensor IC 44 measures the magnetic strength generated by the magnet 32 ​​and obtains a measurement signal indicating the magnetic strength. This measurement signal is, for example, a digital signal that is determined to have a linear relationship with the magnetic strength. The magnetic strength may be any of magnetic flux density (unit: T), magnetic field strength (unit: A / m), and magnetic flux (unit: Wb).

[0023] The DSP 46 functions as a D / A converter that converts the digital signal supplied from the magnetic sensor IC 44 into an analog signal. The execution function of the DSP 46 will be described in detail later with reference to FIG.

[0024] The amplifier 48 amplifies and outputs the analog voltage signal supplied from the DSP 46. The amplified signal waveform is supplied to a higher-level device (not shown) through a predetermined output port.

[0025] Fig. 4 is a functional block diagram of the DSP 46 shown in Fig. 3. The DSP 46 functions as a mode selection unit 50 (corresponding to a "selection unit"), a front-stage switch 52, a rear-stage switch 54, an inspection and determination unit 56 (corresponding to a "determination unit"), a magnetic conversion unit 58, an angle conversion unit 60, and a voltage output unit 62.

[0026] The mode selection unit 50 selectively executes a plurality of modes including a measurement mode, an inspection mode, and a notification mode. The "measurement mode" is a mode in which a signal indicating the relative rotation angle between the main body unit 12 and the rotating unit 14 is generated from the acquired measurement signal and output. The "inspection mode" is a mode in which a signal indicating the magnetic strength is generated from the acquired measurement signal and output. The "notification mode" is a mode in which a signal having a different signal level from that in the measurement mode is generated and output.

[0027] The mode selection unit 50 starts the inspection mode when it receives a start command triggered by the supply of power from an external device including a higher-level controller. Specifically, the mode selection unit 50 controls the switches so that the output terminal of the front-stage switch 52 is connected to the inspection and determination unit 56 and the input terminal of the rear-stage switch 54 is connected to the magnetic conversion unit 58.

[0028] The mode selection unit 50 starts the measurement mode when it receives a positive determination result from the inspection and determination unit 56. Specifically, the mode selection unit 50 performs switch control so as to connect the output terminal of the front-stage switch 52 and the input terminal of the rear-stage switch 54 to the angle conversion unit 60, respectively.

[0029] The mode selection unit 50 starts the notification mode when it receives a negative determination result from the inspection and determination unit 56. Specifically, the mode selection unit 50 releases the connections of the front-stage switch 52 and the rear-stage switch 54, and instructs the voltage output unit 62 to output a signal (hereinafter also referred to as an "abnormality notification signal") whose signal level is different from that in the measurement mode.

[0030] The front-stage switch 52 is configured to be able to switch the output destination of the measurement signal in accordance with switch control by the mode selection section 50. One output end of the front-stage switch 52 is connected to the inspection and determination section 56. The other output end of the front-stage switch 52 is connected to the angle conversion section 60.

[0031] The rear-stage switch 54 is configured to be able to switch the supply source of the output signal in accordance with switch control by the mode selection unit 50. One input end of the rear-stage switch 54 is connected to the magnetic conversion unit 58. The other input end of the rear-stage switch 54 is connected to the angle conversion unit 60.

[0032] The inspection and determination unit 56 determines whether the magnetic strength measured or the measurement signal acquired during execution of the inspection mode falls within a predetermined range (hereinafter also referred to as the "measurement guarantee range"). For example, the inspection and determination unit 56 obtains a time average of the measurement signal during the execution period of the inspection mode, and determines whether this average value falls within the measurement guarantee range. The inspection and determination unit 56 notifies the mode selection unit 50 of the obtained judgment result, whether positive or negative.

[0033] The magnetic conversion unit 58 converts the measurement signal acquired from the magnetic sensor IC 44 into an output signal (hereinafter also referred to as a "magnetic signal") according to the inspection mode in accordance with a predetermined first conversion table. When the measurement signal has a linear relationship with the magnetic strength, the first conversion table corresponds to a table showing an identity conversion or a linear conversion.

[0034] The angle conversion unit 60 converts the measurement signal acquired from the magnetic sensor IC 44 into an output signal (hereinafter also referred to as an "angle signal") according to the measurement mode in accordance with a predetermined second conversion table. When the measurement signal has a linear relationship with the magnetic strength, the second conversion table corresponds to a table showing a nonlinear conversion.

[0035] The voltage output unit 62 is a D / A converter that converts a digital output signal into an analog voltage signal. The conversion method may be, for example, any of a resistor string type, a resistor ladder type, a current output type, and a delta sigma type.

[0036] Fig. 5 is a diagram showing an example of the correspondence between magnetic flux density and voltage. The horizontal axis of the bar graph indicates magnetic flux density (unit: mT) measured by the magnetic sensor IC 44 (Fig. 3). Regarding the range of voltage that can be output in a normal state (hereinafter, normal output range), for example, the lower limit is set as Vmin = 0.4 V and the upper limit is set as Vmax = 4.0 V. As can be seen from this diagram, the normal output range is the same in the inspection mode and the measurement mode, but the correspondence with the magnetic flux density is different.

[0037] In the inspection mode, the minimum value of the magnetic flux density (e.g., 0 mT) corresponds to the voltage Vmin, and the maximum value of the magnetic flux density (e.g., 127 mT) corresponds to the voltage Vmax. In the example shown in the figure, the voltage within the normal output range is determined to have a linear relationship with the magnetic flux density. As a result, the output resolution of the magnetic flux density expressed by the voltage is roughly constant regardless of the magnitude of the magnetic flux density.

[0038] On the other hand, in the measurement mode, the minimum rotation angle (e.g., 0°) corresponds to the voltage Vmin, and the maximum rotation angle (e.g., 359°) corresponds to the voltage Vmax. Here, it is assumed that the magnetic flux density at a rotation angle of 0° is 30 mT, and the magnetic flux density at a rotation angle of 359° is 70 mT. In the example shown in the figure, the voltage within the normal output range is determined to have a linear relationship with the rotation angle. As a result, the output resolution of the rotation angle expressed by the voltage is roughly constant regardless of the magnitude of the rotation angle.

[0039] As can be seen from this figure, when comparing magnetic flux densities, the expressible range of the inspection mode (0 to 127 mT) is set to include the expressible range of the measurement mode (30 to 70 mT). In other words, even in the range that cannot be output in the measurement mode (0 to 30 mT or 70 to 127 mT), the magnetic flux density measurement results can be quantitatively output by selecting the inspection mode.

[0040] <Operation of angle sensor 24> The angle sensor 24 in this embodiment is configured as described above. Next, the operation of the angle sensor 24 (more specifically, the DSP 46) will be described in detail with reference to the flowchart in FIG.

[0041] 6, the DSP 46 starts the inspection mode in response to the supply of power from the upper controller. Then, the DSP 46 outputs a start-up signal showing a waveform pattern that can identify the start-up state until a certain time (e.g., 20 ms) has elapsed since the start-up.

[0042] In step SP12, the DSP 46 performs signal processing corresponding to the "inspection mode" on the measurement signals that are sequentially input, and outputs a voltage waveform that indicates the measurement result of the magnetic flux density.

[0043] In step SP14, the DSP 46 judges whether or not the magnetic flux density measured in step SP12 is within the measurement guaranteed range. If it is judged to be within the measurement guaranteed range (step SP14: YES), the DSP 46 proceeds to the next step SP16.

[0044] In step SP16, the DSP 46 switches from the current inspection mode to the measurement mode and executes it.

[0045] In step SP18, the DSP 46 performs signal processing corresponding to the "measurement mode" on the measurement signals input sequentially, and outputs a voltage waveform indicating the measurement result of the rotation angle. After this, the DSP 46 continues to measure the rotation angle of the rotating unit 14 while power is being supplied from the external device.

[0046] On the other hand, returning to step SP14, if it is determined that the magnetic flux density is not within the measurement guarantee range (step SP14: NO), the process proceeds to step SP20.

[0047] In step SP20, the DSP 46 switches from the current inspection mode to a notification mode.

[0048] In step SP20, the DSP 46 outputs a voltage waveform notifying that the test result is abnormal. After this, the DSP 46 continues to output the abnormality notification signal while power is being supplied from the external device.

[0049] As described above, the DSP 46 operates according to the flowchart in Fig. 6. The upper controller collects the voltage signals output from the angle sensor 24 in association with the acquisition times, thereby enabling the analysis of changes in the relative positional relationship between objects involved in the detection of the angle (for example, between the magnet 32 ​​and the sensor board 36).

[0050] FIG. 7 is a time chart showing an example of a voltage waveform under normal conditions. The horizontal axis of the graph indicates time (unit: ms), and the vertical axis of the graph indicates voltage (unit: V). When power is supplied to the angle sensor 24, [1] an activation signal over a first execution time (here, 20 ms), [2] a magnetic signal over a second execution time (e.g., 100 ms) longer than the first execution time, and [3] a time series of angle signals are sequentially output. The magnetic signal in this figure corresponds to a voltage signal output during execution of the inspection mode. Meanwhile, the angle signal corresponds to a voltage signal output during execution of the measurement mode.

[0051] Under normal circumstances, the gap G between the magnet 32 ​​and the sensor substrate 36 is set to a length according to the design value. In this case, the magnetic signal transitions within the measurement guarantee range shown by double hatching (converted into magnetic flux density "30 to 70 mT" and converted into voltage "1.25 to 2.36 V") regardless of the rotation angle of the rotating part 14.

[0052] Fig. 8 is a time chart showing an example of a voltage waveform during an abnormality. When power is supplied to the angle sensor 24, a time series of [1] an activation signal over a first execution time (20 ms), [2] a magnetic signal over a second execution time (100 ms), and [3] an abnormality notification signal is output in sequence. The magnetic signal in this figure corresponds to a voltage signal output during execution of the inspection mode. Meanwhile, the abnormality notification signal corresponds to a voltage signal output during execution of the notification mode.

[0053] For example, assume that the gap G between the magnet 32 ​​and the sensor board 36 becomes longer than the design value due to the fixing member 30 slipping downward. In that case, the magnetic signal may transition in a range below the guaranteed measurement range (0 to 30 mT in magnetic flux density conversion, 0.4 to 1.25 V in voltage conversion). In this case, a voltage signal of 0 V is continuously output as an abnormality notification signal. Alternatively, a similar abnormality process may be performed when the magnetic sensor IC 44 fails and no measurement signal is output.

[0054] For example, assume that the gap G between the magnet 32 ​​and the sensor board 36 becomes shorter than the design value due to the sensor board 36 slipping downward. In that case, the magnetic signal may transition in a range above the guaranteed measurement range (equivalent to "70 to 127 mT" in magnetic flux density, or "2.36 to 4.0 V" in voltage). In this case, a voltage signal of Vcc (e.g., around 5 V) is continuously output as an abnormality notification signal.

[0055] <Effects of the embodiment> As described above, the angle sensor 24 is fixed to the rotating part 14 which is rotatable relative to the main body part 12 of the hydraulic rotary joint 10. The angle sensor 24 is provided at a distance from the magnet 32 ​​which is built into or externally attached to the main body part 12, and includes a magnetic sensor IC 44 which measures the strength of the magnetism emitted by the magnet 32 ​​and acquires a measurement signal indicating the strength of the magnetism, a mode selection unit 50 which selectively executes a plurality of modes including a measurement mode which generates an output signal indicating the relative rotation angle between the main body part 12 and the rotating part 14 from the acquired measurement signal, and an inspection mode which generates an output signal indicating the magnetic strength from the acquired measurement signal, and a voltage output unit 62 which outputs the output signal generated in accordance with the selection of the mode.

[0056] With this configuration, the relative rotation angle between the main body 12 and the rotating part 14 can be detected by selecting the measurement mode, while the length of the gap G between the magnet 32 ​​and the magnetic sensor IC 44 can be estimated using the magnetic strength detected when the inspection mode is selected. This makes it possible to analyze the relative positional relationship between objects involved in angle detection while utilizing the existing angle detection function.

[0057] The mode selection unit 50 may start the inspection mode when power is supplied from an external device, and switch from the inspection mode to the measurement mode if the magnetic strength measured or the measurement signal obtained during the inspection mode is within a predetermined range. This ensures that the inspection is performed every time the angle sensor 24 becomes usable, and that if the magnetic strength or the measurement signal is within a predetermined range, the angle sensor 24 is determined to be normal, and the rotation angle can be automatically shifted to a state where it can be measured.

[0058] Furthermore, the voltage output unit 62 may start the inspection mode when power is supplied from an external device, and if the magnetic strength measured or the measurement signal obtained during the inspection mode is not within a predetermined range, switch from the inspection mode to a notification mode that generates an output signal with a different signal level from that in the measurement mode. This ensures that inspection is performed every time the angle sensor 24 becomes usable, and if the magnetic strength or the measurement signal is not within a predetermined range, it can be determined that an abnormality exists and notify the outside that the measurement mode will not be executed.

[0059] The main body 12 and the rotating part 14 may be arranged coaxially along the vertical direction. In this case, gravity acts on the main body 12 and the rotating part 14, making it easier for the relative positional relationship to change. This makes it more effective to estimate the length of the gap G in the inspection mode.

[0060] <Modification> The present invention is not limited to the above specific examples. In other words, the above specific examples, to which a person skilled in the art has made appropriate design modifications, are also included within the scope of the present invention as long as they have the characteristics of the present invention. In addition, the elements of the above-mentioned embodiment and the modified examples described below can be combined to the extent technically possible, and combinations of these are also included within the scope of the present invention as long as they include the characteristics of the present invention.

[0061] In the above embodiment, an example was given of a case in which the angle sensor 24 is incorporated into the hydraulic rotary joint 10 and the rotation angle that changes as the swing motor 22 is driven is detected, but the device to which the angle sensor 24 is applied or the type of rotating body to be measured are not limited to these combinations.

[0062] In the embodiment described above, the angle sensors 24 are arranged to be spaced apart in the axial direction of the fixed member 30, but instead, they may be arranged to be spaced apart in the circumferential direction of the fixed member 30. Also, in the embodiment described above, the magnet 32 ​​is attached externally to the fixed member 30, but instead, the magnet 32 ​​may be built into the fixed member 30.

[0063] In the above embodiment, the hydraulic rotary joint 10 is disposed so that its axial direction substantially coincides with the vertical direction, but the orientation of the hydraulic rotary joint 10 is not limited to this. Specifically, the hydraulic rotary joint 10 may be disposed so that its axial direction is along the vertical direction, or along the horizontal direction. Note that "along the vertical direction" includes not only the case where the axial direction coincides with the vertical direction, but also the case where the axial direction is inclined within a predetermined range (generally within ±20 degrees) with respect to the vertical direction.

[0064] In the above embodiment, the inspection and determination unit 56 performs range determination on the measurement signal, but instead, the inspection and determination unit 56 may be configured to perform range determination on the output signal indicating the magnetic strength (i.e., the magnetic signal). In this case, the arrangement of the inspection and determination unit 56 and the magnetic conversion unit 58 in Fig. 4 may be reversed. In addition, when the magnetic conversion unit 58 performs an identity conversion, the configuration of the magnetic conversion unit 58 may be omitted.

[0065] In the above embodiment, the inspection and determination unit 56 performs a determination on the measurement signal, but instead, the angle sensor 24 does not have to perform the determination. In this case, an external device (e.g., a higher-level controller) connected to the angle sensor 24 may analyze the output signal.

[0066] In the above embodiment, the voltage output unit 62 outputs a voltage waveform, but instead, it may be configured to output a current waveform. Also, the normal output range of the voltage (see FIG. 5) may be appropriately changed as necessary.

[0067] In the above embodiment, the measurement guarantee range corresponds to the expressible range of the measurement mode (30 to 70 mT), but there may be cases where it does not match this. Specifically, the measurement guarantee range may be [1] only the lower limit, [2] only the upper limit, or [3] both the upper and lower limits with a predetermined margin (for example, any value between 1 and 5 mT).

[0068] [Explanation of symbols] 10... hydraulic rotary joint, 12... main body portion (first object), 14... rotating portion (second object), 26... angle sensor, 32... magnet, 44... magnetic sensor IC (measurement portion), 50... mode selection portion (selection portion), 62... voltage output portion (output portion)

Claims

1. An angle sensor fixed to a second object that is rotatable relative to the first object and spaced apart in an axial direction of the relative rotation, a measurement unit that is provided at a distance in the axial direction from a magnet that is built into or externally attached to the first object, and that measures a magnetic strength generated by the magnet and acquires a measurement signal indicating the magnetic strength; a selection unit that selectively executes a plurality of modes including a measurement mode that generates an output signal indicating a relative rotation angle between the first object and the second object from the measurement signal acquired by the measurement unit, and an inspection mode that generates an output signal indicating the strength of the magnetic field from the measurement signal; an output unit that outputs an output signal generated in response to the mode selected by the selection unit; Equipped with The angle sensor is characterized in that the selection unit calculates a time average of the measurement signal acquired by measurement at one location by the measurement unit while the inspection mode is being executed, and switches to a different mode depending on the time average.

2. 2. The angle sensor according to claim 1, wherein the selection unit switches from the inspection mode to the measurement mode when the time average obtained during execution of the inspection mode is within a predetermined range.

3. 2. The angle sensor according to claim 1, wherein the selection unit switches from the inspection mode to a notification mode in which an output signal having a different signal level than that in the measurement mode is generated when the time average calculated during execution of the inspection mode is not within a predetermined range.

4. The angle sensor described in Claim 1, characterized in that the selection unit starts the inspection mode in response to a supply of power from an external device.

5. 5. The angle sensor according to claim 1, wherein the first object and the second object are arranged coaxially along a vertical direction.

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