JP2021025933A - Displacement output device and electric actuator - Google Patents

Abstract

To reduce the size and cost of an electric actuator by preventing the restriction of the arrangement of a displacement output device.SOLUTION: A displacement output device (70) is a displacement output device (70) for outputting a signal corresponding to the displacement of the output mechanism of the electric actuator including the output mechanism which is mechanically displaced according to the rotation of a motor, a sensor which detects the mechanical displacement of the output mechanism, and a control part which controls the rotation of the motor on the basis of the output of the sensor and includes a first terminal (W) which is connected to a reference potential, a second terminal (B) which has an arbitrary input voltage applied to the first terminal, a third terminal (R) which outputs an output voltage corresponding to the displacement of the output mechanism with respect to the input voltage, an arithmetic processing part (73) which calculates the ratio of the displacement of the output mechanism on the basis of the output of the sensor, and an output circuit (75) which generates a voltage corresponding to the ratio calculated by the arithmetic processing part with respect to the input voltage and outputs the voltage to the third terminal as the output voltage.SELECTED DRAWING: Figure 1

Description

The present invention relates to a displacement output device and an electric actuator, and more particularly to an electric actuator including a displacement output device and a displacement output device that output a signal corresponding to a mechanical displacement of the output mechanism of the electric actuator.

In an electric actuator equipped with an output mechanism that mechanically displaces according to the rotation of a motor, a potentiometer mechanically connected to the output mechanism outputs a signal corresponding to the displacement of the output mechanism to the outside. In principle, the potentiometer is a variable resistor composed of a resistor and a movable electrode (brush) capable of sliding on the resistor, as shown in FIG. A voltage is applied to both ends (B, W), and the voltage divided according to the position of the movable electrode is output from the terminal R connected to the movable electrode. For example, in the case of a rotary potentiometer that detects a rotation angle, the movable electrode of the potentiometer is mechanically connected to the output shaft of the electric actuator and slides on the resistor as the output shaft rotates.

For example, Patent Document 1 describes that a potentiometer is mounted on the outside of a housing accommodating a gear reduction mechanism of an electric actuator, and the rotation of an output shaft is transmitted to the potentiometer. Further, Patent Document 2 describes that a potentiometer is attached to one end of the output shaft of the actuator.

Japanese Unexamined Patent Publication No. 2-3251 Japanese Unexamined Patent Publication No. 2011-200025

However, the potentiometer requires a certain size due to the structure in which the movable electrode is slid with respect to the resistor. Further, when a potentiometer is provided in the transmission system of the electric actuator as the displacement output device, the potentiometer must be mechanically connected to the output shaft, and therefore, the arrangement of the potentiometer is greatly restricted. Therefore, the provision of the potentiometer has been a cause of hindering the miniaturization and cost reduction of the electric actuator.
Further, a clearance is provided for connecting the potentiometer to the output shaft or the like, and this clearance causes an error. Further, since the movable electrode slides on the resistor, it is inevitable that the reliability will decrease due to aging.

Furthermore, since the voltage applied to both ends of the potentiometer is not standardized, the potentiometer outputs from the movable electrode of the potentiometer depending on the magnitude of the voltage applied to the resistor of the potentiometer even if the displacement of the output mechanism is the same. The magnitude of the voltage produced may vary from application to application.

Therefore, an object of the present invention is to make it possible to reduce the size, reduce the cost, improve the reliability, and process various signals of the electric actuator without being restricted by the arrangement of the displacement output device.

In order to achieve the above object, the displacement output device according to the present invention includes an output mechanism that mechanically displaces according to the rotation of the motor, a sensor that detects the mechanical displacement of the output mechanism, and the sensor. A first displacement output device (70) that outputs a signal corresponding to the displacement of the output mechanism of an electric actuator including a control unit that controls the rotation of the motor based on the output, and is connected to a reference potential. A third terminal (W), a second terminal (B) to which an arbitrary input voltage is applied to the first terminal, and a third terminal (B) that outputs an output voltage corresponding to the displacement of the output mechanism with respect to the input voltage. According to the terminal (R), the arithmetic processing unit (73) that calculates the displacement ratio of the output mechanism based on the output of the sensor, and the ratio calculated by the arithmetic processing unit with respect to the input voltage. It has an output circuit (75) that generates a voltage and outputs the output voltage to the third terminal.

In the displacement output device according to the embodiment of the present invention, an analog / digital conversion circuit (72) that converts the magnitude of the input voltage applied to the second terminal into analog / digital and inputs it to the arithmetic processing unit. ) Is further provided, and the arithmetic processing unit (73) calculates the magnitude of the output voltage from the output of the sensor and the magnitude of the input voltage input from the analog / digital conversion circuit. A digital / analog conversion circuit (74) that digitally / analog-converts the magnitude of the output voltage calculated by the arithmetic processing unit, and a voltage having a magnitude converted by the digital / analog conversion circuit are generated. It includes an analog output circuit (75) that outputs as an output voltage.

In the displacement output device according to the embodiment of the present invention, the first photocoupler (78) that electrically insulates the analog / digital conversion circuit (72) and the arithmetic processing unit (73), and the above. It has a second photocoupler (79) that electrically insulates the digital / analog conversion circuit and the arithmetic processing unit.

In the displacement output device according to the embodiment of the present invention, the first modulation circuit (701) that outputs a modulated digital signal modulated according to the displacement ratio of the output mechanism, and the first modulation circuit (701) using the modulated digital signal. A second modulation circuit (740) that modulates the voltage applied to the two terminals is further provided, and the output circuit includes an analog output circuit (750) that smoothes and outputs the voltage output from the second modulation circuit. Including.

In the displacement output device according to the embodiment of the present invention, the second modulation circuit includes a photocoupler (770) that electrically insulates the arithmetic processing unit and the analog output circuit.

Further, the electric actuator according to the present invention includes a motor (10), a drive circuit (60) for supplying an electric current to the motor, an output mechanism (30) that is mechanically displaced according to the rotation of the motor, and the above. A sensor (40) that detects the mechanical displacement of the output mechanism, a control unit (50) that controls the rotation of the motor based on the output of the sensor, and a first terminal (W) connected to a reference potential. It has a second terminal (B) for applying an arbitrary input voltage to the reference potential, and a third terminal (R) for outputting an output voltage corresponding to the displacement of the output mechanism with respect to the input voltage. A displacement output device (70) is provided, and the displacement output device is the displacement output device described above.

The electric actuator according to the embodiment of the present invention includes an arithmetic processing unit (510) including an arithmetic processing circuit (511), a storage device (512), and an interface, and the arithmetic processing unit is the said. It is configured to operate as a control unit (50) and an arithmetic processing unit (73) of the displacement output device.

According to the present invention, it is possible to reduce the size of the electric actuator, reduce the cost, improve the reliability, and perform various signal processing without being restricted by the arrangement of the displacement output device.

FIG. 1 is a diagram showing a configuration of an electric actuator according to a first embodiment of the present invention. FIG. 2 is a diagram showing a hardware configuration of the electric actuator according to the first embodiment. FIG. 3 is a flowchart illustrating the operation of the displacement output device of the electric actuator according to the first embodiment. FIG. 4A is a diagram for explaining the relationship (normal operation) between the opening degree on the output side and the magnitude of the output voltage. FIG. 4B is a diagram for explaining the relationship (reverse operation) between the opening degree on the output side and the magnitude of the output voltage. FIG. 4C is a diagram for explaining the relationship (offset and gain) between the opening degree on the output side and the magnitude of the output voltage. FIG. 4D is a diagram for explaining the relationship (broken line) between the opening degree on the output side and the magnitude of the output voltage. FIG. 5 is a diagram showing a configuration example of a displacement device for the electric actuator according to the first embodiment. FIG. 6 is a diagram showing another configuration example of the displacement device for the electric actuator according to the first embodiment. FIG. 7 is a diagram showing a configuration of an electric actuator according to a second embodiment of the present invention. FIG. 8 is a flowchart illustrating the operation of the displacement output device of the electric actuator according to the second embodiment. FIG. 9A is a diagram for explaining the relationship (normal operation) between the opening degree on the output side and the duty ratio. FIG. 9B is a diagram for explaining the relationship (reverse operation) between the opening degree on the output side and the duty ratio. FIG. 9C is a diagram for explaining the relationship (offset and gain) between the opening degree on the output side and the duty ratio. FIG. 9D is a diagram for explaining the relationship (polygonal line) between the opening degree on the output side and the duty ratio. FIG. 10 is a diagram showing a configuration example of a displacement device for the electric actuator according to the second embodiment. FIG. 11 is a diagram showing another configuration example of the displacement device for the electric actuator according to the second embodiment. FIG. 12 is a diagram illustrating the principle of the potentiometer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 shows the configuration of the electric actuator 100 according to the first embodiment of the present invention.
The electric actuator 100 includes a motor 10, a speed reducer 20 that serves as a transmission mechanism for transmitting the rotation of the motor 10, and a rotating shaft 30 that rotates around an axis according to the rotation of the motor 10 transmitted via the speed reducer 20. An angle sensor 40 that detects the rotation angle of the rotating shaft 30, a control unit 50 that controls the rotation of the motor 10, a drive circuit 60 that rotates the motor 10 based on a control signal from the control unit 50, and a rotating shaft. It is provided with a displacement output device 70 that outputs a signal corresponding to the position of 30.

Of these, for the motor 10, for example, a synchronous motor, a brushless DC motor, a stepping motor, or the like can be used, but a power source other than these may be used.

The speed reducer 20 typically comprises a plurality of gears combined with each other. The mechanism may be a combination of a chain or a belt together with the gear or instead of the gear. In the present embodiment, the speed reducer 20 decelerates the rotation of the motor 10 by a predetermined reduction ratio G and transmits the rotation to the rotation shaft 30.

The rotating shaft 30 is a rod-shaped member whose one end is connected to the output shaft of the speed reducer 20 and is made of highly rigid metal or the like, and constitutes an output mechanism that is mechanically displaced according to the rotation of the motor 10. Although not shown, the other end of the rotating shaft 30 is connected to the valve body of the valve and other elements to be operated.

In the electric actuator 100 according to the present embodiment, the mechanical displacement of the rotating shaft 30 which is an output mechanism is the rotation angle around the axis. The angle sensor 40 is a device that detects the rotation angle of the rotation shaft 30. In the present embodiment, the angle sensor 40 uses a potentiometer composed of a variable resistor, but instead, a plurality of rotations different from each other from an arbitrary reference position within the rotation range of the rotation shaft 30. An angle position sensor equipped with a position sensor provided at each position corresponding to an angle, an absolute position sensor such as an absolute rotary encoder that outputs a code signal corresponding to an absolute angle position of the rotating shaft 30, and an absolute position sensor. An incremental rotary encoder or the like, which is a relative position sensor that outputs a pulse corresponding to the rotation angle of the rotation shaft 30, may be used.

The control unit 50 determines the operation amount according to the deviation between the target angle θsp given from a higher-level device (not shown) and the rotation angle θpt of the rotation shaft 30 detected by the angle sensor 40, and operates the drive circuit 60. Controls the rotation of the motor 10. More specifically, the control unit 50 determines the manipulated variable OA according to the deviation between the target angle θsp and the rotational angle θpt of the rotating shaft 30 detected by the angle sensor 40, and the drive circuit 60 determines the manipulated variable OA. The drive signal Dv corresponding to is given. For example, in the case of general proportional control (P control), it is calculated by OA = α (θsp−θpt) (where α is a proportionality constant). The control unit 50 generates a drive signal Dv based on the manipulated variable OA thus obtained and outputs the drive signal Dv to the drive circuit 60.

The proportional control described above is only an example of controlling the rotation angle of the motor 10 or the rotation shaft 30, and in the present invention, for example, in addition to PD control and PID control, a model using a neural network model or other model. Any control method such as control may be used.

The drive circuit 60 includes, for example, a plurality of MOSFETs, and supplies a current to the windings of the motor 10 by appropriately turning on / off switching devices such as MOSFETs and transistors by a drive signal Dv from the control unit 50. 10 can be rotated.

The displacement output device 70 is a device that outputs a signal according to the position of the rotating shaft 30 instead of the potentiometer provided as the displacement output device in the conventional electric actuator. In the electric actuator 100 according to the present embodiment, in the displacement output device 70, an arbitrary input voltage is applied to the first terminal W connected to the reference potential and the first terminal, similarly to the conventional potentiometer. The second terminal B and the third terminal R that outputs a voltage corresponding to the position of the rotating shaft 30 with respect to this input voltage, more specifically, a voltage corresponding to the current rotation angle with respect to the maximum rotating angle of the rotating shaft 30. And have. In the present embodiment, the first terminal W is set to the ground (GND) level.

The displacement output device 70 further has a ratio Θ [%] (hereinafter, this) according to the current rotation angle with respect to the maximum rotation angle of the rotation shaft 30 based on the rotation angle θpt of the rotation shaft 30 detected by the angle sensor 40. The arithmetic processing unit 73 that calculates the ratio Θ is simply referred to as “opening Θ”), and the digital / analog conversion circuit that digitally / analog-converts the output of the arithmetic processing unit 73 and inputs it to the analog output circuit 75. (Hereinafter referred to as "D / A conversion circuit".) A third output voltage is generated according to the ratio calculated by the arithmetic processing unit 73 with respect to the input voltage input to the 74 and the second terminal B. An analog output circuit 75 that outputs to the terminal R is provided.

In the present embodiment, more specifically, the arithmetic processing unit 73 outputs from the third terminal W from the output magnitude Va of the angle sensor 40 and the input voltage magnitude Vw input to the second terminal B. It is configured to calculate the magnitude Vo of the output voltage to be output.

The displacement output device 70 is referred to as an analog input circuit 71 and an analog / digital conversion circuit (hereinafter referred to as "A / D conversion circuit") for inputting an input voltage applied to the second terminal B to the arithmetic processing unit 73. ) 72 is provided. Further, it includes an analog input circuit 76 and an A / D conversion circuit 77 for inputting the output of the angle sensor 40 to the arithmetic processing unit 73.

FIG. 2 shows an example of the hardware configuration of the electric actuator 100 described above. In this example, the control board 500 includes an arithmetic processing device 510, a power supply circuit 520 that supplies power to the arithmetic processing apparatus 510, and analog input circuits 71 and 76 and analog output circuits 75 that input or output analog signals. It is provided. The arithmetic processing device 510 includes, for example, an arithmetic processing circuit (CPU) 511, a storage device (memory) 512, A / D conversion circuits 72 and 77, a D / A conversion circuit 74, and various interface circuits 513 and 514. It is configured to be communicable via bus 518.

In the arithmetic processing device 510, the target angle θsp and the angle sensor 40 given as the control unit 50 described above via the interface circuit 513 by the CPU 511 executing various information processing according to the computer program stored in the memory 512. The drive circuit 60 is operated according to the deviation from the rotation angle θpt of the rotation shaft 30 detected by, controls the rotation of the motor 10, and is output from the analog output circuit 75 as the arithmetic processing unit 73 of the displacement output device 70. Calculate the magnitude of the output voltage to be used.
In addition to the program, the memory 512 may store the magnitude of the maximum rotation angle of the rotation shaft 30.

The analog input circuits 71 and 76 amplify, level shift, shape the waveform, and remove noise so that the analog input signal from the outside can be input to the A / D conversion circuits 72 and 77 in the subsequent stage. It is a circuit, and a known analog input circuit composed of a resistor and a transistor may be appropriately used.
Further, the analog output circuit 75 generates a voltage having a magnitude Vo calculated by the arithmetic processing unit 73 from, for example, a voltage Vcc supplied from the power supply circuit 520 or a voltage Vb supplied to the second terminal B. It is a circuit to output, and a known analog output circuit including an amplifier circuit may be appropriately used.

[Operation of displacement output device 70]
As shown in FIG. 3, the procedure of displacement output by the displacement output device 70 first detects the mechanical displacement of the rotating shaft 30, that is, the rotation angle by the angle sensor 40, and acquires the output (step S10). .. After acquiring the rotation angle, it is converted into a ratio of the rotation angle to the maximum rotation angle, that is, an opening degree Θ [%] on the output side (step S20). Then, the magnitude of the voltage Vb applied to the second terminal B is measured (step S30), and the opening degree Θ [%] calculated in step S20 to the magnitude of the voltage Vb applied to the second terminal B. By multiplying by the ratio, the magnitude of the analog output voltage to be output from the third terminal R is calculated (step S40), and the voltage of that magnitude is output from the analog output circuit 75 (step S50).

In step S40 described above, the signal processing for calculating the magnitude of the analog output voltage Vo to be output from the third terminal R from the opening degree Θ [%] on the output side passes through the origin and is positive as shown in FIG. 4A. It becomes a normal operation with an inclination. The relationship between the opening degree Θ [%] on the output side and the analog output voltage Vo at this time can be expressed by the following equation.

Vo = Vb ・ Θ / 100

In the above example, the process of calculating the magnitude of the analog output voltage Vo to be output from the third terminal R from the opening degree Θ [%] on the output side by the arithmetic processing unit 73 is as shown in FIG. 4A. Although it is considered to be a normal operation, in the present invention, in generating the output voltage Vo corresponding to the opening degree Θ [%] on the output side with respect to the magnitude of the input voltage Vb applied to the second terminal B, the above is described. In addition to the positive operation performed, for example, various relationships as shown in FIGS. 4B to 4D can be used.

FIG. 4B is a so-called reverse operation. The relationship between the opening degree Θ [%] on the output side and the analog output voltage Vo can be expressed by the following equation.

Vo = Vb ・ (100-Θ) / 100

FIG. 4C is an example of using offset Vost and gain G. The relationship between the output opening degree Θ [%] and the analog output voltage Vo can be expressed by the following equation.

Vo = Vb ・ G ・ Θ / 100 + Vost

FIG. 4D is an example (line) in which the gain G changes depending on the range.

As described above, the signal processing for calculating the output voltage Vo according to the opening degree Θ [%] on the output side with respect to the magnitude of the input voltage Vb applied to the second terminal B is a normal operation. On the basis of, reverse operation, offset, gain, polygonal line, etc. can be considered, and these may be combined, and the relationship is not limited to the above.

As described above, in the displacement output device 70, a voltage corresponding to the rotation angle of the rotating shaft 30 is output from the third terminal R based on the output of the angle sensor 40. Therefore, as seen in the prior art, the machine It is not necessary to provide a potentiometer having a similar structure in the transmission system of the electric actuator. Further, the ratio of the rotation angle of the rotation shaft 30 detected by the angle sensor 40 to the maximum rotation angle is calculated, and output from the third terminal R based on this ratio and the magnitude of the input voltage applied to the second terminal B. Since the magnitude of the output voltage Vo is calculated, the rotation angle of the rotating shaft 30 can be expressed by the ratio of the magnitudes of the voltage regardless of the magnitude of the input voltage applied to the second terminal B.

[Structure 1 of the displacement output device according to the first embodiment]
FIG. 5 shows the configuration of the displacement output device 70A according to the configuration example 1 of the present embodiment.
The displacement output device 70A according to the configuration example 1 insulates and separates the circuit that handles analog signals from the circuit that handles digital signals, and uses a power source in the electric actuator 100 as a reference voltage for the analog input circuit 71 and the analog output circuit 75. The isolated voltage Vcc1 generated by the circuit 520 is used, and the internal voltage Vcc is also generated.
Specifically, as shown in FIG. 5, the A / D conversion circuit 72 and the arithmetic processing unit 73 are electrically insulated by the first photocoupler 78. The output of the first photocoupler 78 is input to the arithmetic processing unit 73 via the interface circuit 517 conforming to SPI / I2C or the like. Further, the arithmetic processing unit 73 and the D / A conversion circuit 74 are insulated and separated by a second photocoupler 79. The output of the arithmetic processing unit 73 is input to the photocoupler 79 via an interface circuit 515 compliant with SPI / I2C or the like.

[Structure 2 of the displacement output device according to the first embodiment]
FIG. 6 shows the configuration of the displacement output device 70B according to the configuration example 2 of the present embodiment.
The displacement output device 70B according to the configuration example 2 is common to the displacement output device 70A according to the configuration example 1 described above in that the circuit that handles analog signals and the circuit that handles digital signals are isolated and separated by a photocoupler. As the reference voltage of the analog input circuit 71 and the analog output circuit 75, the voltage Vb given to the second terminal B from the outside may be used.

[Second Embodiment]
Next, the electric actuator 100A according to the second embodiment of the present invention will be described with reference to FIGS. 7 to 11. The components common to the electric actuator 100 according to the first embodiment described above are designated by the same reference numerals, and detailed description thereof will be omitted.

In the first embodiment described above, the arithmetic processing unit 73 of the displacement output device 70 is the third from the output magnitude Va of the angle sensor 40 and the input voltage magnitude Vw input to the second terminal B. In the second embodiment, the displacement output device 700 is modulated according to the input signal, whereas the magnitude of the output voltage Vo to be output from the terminal W is calculated. A point including a first modulation circuit 701 that outputs a modulated digital signal and a second modulation circuit 740 that modulates an input voltage applied to the second terminal B by a modulated digital signal output from the first modulation circuit 701. The difference is that the arithmetic processing unit 73 calculates the ratio of the rotation angle of the rotation shaft 30 detected by the angle sensor 40 to the maximum rotation angle, that is, the opening degree Θ [%] and inputs it to the first modulation circuit 701. There is.

Of these, the first modulation circuit 701 outputs a modulated digital signal whose pulse width is modulated (PWM) according to the opening degree Θ [%] calculated by the arithmetic processing unit 73.
Further, an analog output circuit 750 including a smoothing circuit is provided after the second modulation circuit 740. The PWM-modulated voltage output from the second modulation circuit 740 is smoothed by the analog output circuit 750 and output to the third terminal R as the output voltage Vo.

[Operation of displacement output device 700]
As shown in FIG. 8, the procedure of displacement output by the displacement output device 700 first detects the mechanical displacement of the rotating shaft 30, that is, the rotation angle by the angle sensor 40, and acquires the output (step S110). .. After acquiring the rotation angle, it is converted into a ratio of the rotation angle to the maximum rotation angle, that is, an opening degree Θ [%] on the output side (step S120). Then, the PWM modulation rate corresponding to the opening degree Θ [%], that is, the duty ratio D [%] is calculated (step S130), and the PWM modulation signal of the duty ratio D [%] is transmitted from the first modulation circuit 701. Output (step S140), the input voltage is modulated according to the PWM modulation signal by the second modulation circuit 740 (step S150), and the modulated input voltage is smoothed and output (step S160).

In step S140 described above, the signal processing performed by the arithmetic processing unit 73 for calculating the duty ratio D [%] from the opening degree Θ [%] on the output side passes through the origin and has a positive inclination as shown in FIG. 9A. It becomes a normal operation to have. The relationship between the opening degree Θ [%] and the duty ratio at this time can be expressed by the following equation, where 1 is the proportionality constant.

D = Θ

In the above example, the relationship between the opening degree Θ [%] on the output side and the duty ratio D [%] is regarded as a normal operation, but in the present invention, the duty ratio D according to the opening degree Θ [%] on the output side In calculating [%], in addition to the above-mentioned normal operation (FIG. 9A), for example, various relationships as shown in FIGS. 9B to 9D can be used.

FIG. 9B is a so-called reverse operation. The relationship between the opening degree Θ [%] on the output side and the duty ratio D [%] can be expressed by the following equation.

D = 100-Θ

FIG. 9C is an example in which the offset Dost and the gain G are used. The relationship between the opening degree Θ [%] on the output side and the duty ratio D [%] can be expressed by the following equation.

D = G · Θ + Dost

FIG. 9D is an example (line chart) in which the gain G changes depending on the range.

Regarding the signal processing when calculating the duty ratio D [%] according to the opening degree Θ [%] on the output side, as described above, the reverse operation, offset, gain, polygonal line, etc. are based on the normal operation. It is conceivable, and these may be combined, and the relationship is not limited to the above.

Also in the present embodiment, since the voltage corresponding to the rotation angle of the rotating shaft 30 is output from the third terminal R based on the output of the angle sensor 40, it has a mechanical structure as seen in the conventional technique. It is not necessary to install the potentiometer in the transmission system of the electric actuator.
Further, the input applied to the second terminal B is input by PWM-modulating the input voltage applied to the second terminal B according to the ratio Θ of the rotation angle of the rotation shaft 30 detected by the angle sensor 40 to the maximum rotation angle. It is not necessary to input the magnitude of the voltage to the arithmetic processing unit 73. Therefore, regardless of the magnitude of the input voltage applied to the second terminal B, not only the rotation angle of the rotating shaft 30 can be expressed by the ratio of the magnitude of the voltage, but also the input voltage applied to the second terminal B can be expressed. The input circuit and A / D conversion circuit for the above are not required, and the displacement output device can be realized with a simpler circuit.

[Structure 1 of the displacement output device according to the second embodiment]
FIG. 10 shows the configuration of the displacement output device 700A according to the configuration example 1 of the present embodiment.
In the displacement output device 700A according to the configuration example 1, the circuit that handles the analog signal and the circuit that handles the digital signal are isolated and separated, and the power supply circuit 520 is generated in the electric actuator 100 as the reference voltage of the analog output circuit 750. The insulated voltage Vcc1 is used, and the internal voltage Vcc is also generated.
Specifically, as shown in FIG. 10, the second modulation circuit 740 is electrically isolated by the photocoupler 770.

[Structure 2 of the displacement output device according to the second embodiment]
FIG. 11 shows the configuration of the displacement output device 700B according to the configuration example 2 of the present embodiment.
The displacement output device 700B according to the configuration example 2 is common to the displacement output device 700A according to the configuration example 1 described above in that the circuit that handles analog signals and the circuit that handles digital signals are isolated and separated by a photocoupler. As the reference voltage of the analog output circuit 750, a voltage Vb given to the second terminal B from the outside may be used.

[Effect of Embodiment]
As described above, according to the electric actuators 100 and 100A according to the embodiment of the present invention, the potentiometer as a conventional displacement output device is realized by an electronic circuit, so that the arrangement of the displacement output device is not restricted. , It is possible to reduce the size and cost of the electric actuator.

Further, since the control unit 50 and the arithmetic processing unit 73 described above can be realized by one arithmetic processing unit 510, the electric actuator can be miniaturized.

Further, since it is not necessary to connect the potentiometer as a displacement output device to the output shaft or the like, an error due to clearance does not occur. In addition, it is possible to avoid a decrease in reliability due to the movable electrode sliding on the resistor.

Further, according to the displacement output devices 70 and 700 according to the embodiment of the present invention, the ratio of the rotation angle of the rotation shaft 30 detected by the angle sensor 40 to the maximum rotation angle and the input voltage applied to the second terminal B. Since the magnitude of the output voltage Vo output from the third terminal R is calculated based on the magnitude of, the rotation angle of the rotating shaft 30 is set to the voltage regardless of the magnitude of the input voltage applied to the second terminal B. It can be expressed by the ratio of the sizes of.

As for the signal processing when calculating the output voltage Vo and the duty ratio D, as described above, the reverse operation, the offset, the gain, the polygonal line, etc. can be considered based on the normal operation, and these are combined. It can correspond to various outputs.
Further, in the above-described embodiment, a photocoupler is used to electrically isolate and separate a circuit that handles analog signals from a circuit that handles digital signals, but any device that can transmit signals and can insulate them. , Any device may be used in place of the photocoupler.

Further, in the above embodiment, the power supply circuit of the electric actuator has been described as an example, but the present invention applies not only to the electric actuator but also to all products that output a signal according to the mechanical displacement of the output mechanism. Applicable.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the structure and details of the present invention within the scope of the present invention.

The present invention can be applied to an electric actuator provided with a displacement output device.

100, 100A ... Electric actuator, 10 ... Motor, 20 ... Reducer, 30 ... Rotating shaft, 40 ... Angle sensor, 50 ... Control unit, 500 ... Control board, 510 ... Arithmetic processing device, 511 ... CPU, 512 ... Memory, 60 ... Drive circuit, 70 ... Displacement output device, 71,76 ... Analog input circuit, 75,750 ... Analog output circuit, 72, 77 ... A / D conversion circuit, 74 ... D / A conversion circuit, 78,79,770 ... photocoupler, 701 ... first modulation circuit, 740 ... second modulation circuit.

Claims (7)

An electric motor including an output mechanism that mechanically displaces according to the rotation of the motor, a sensor that detects the mechanical displacement of the output mechanism, and a control unit that controls the rotation of the motor based on the output of the sensor. A displacement output device that outputs a signal according to the displacement of the output mechanism of the actuator.
The first terminal connected to the reference potential and
A second terminal to which an arbitrary input voltage is applied to the first terminal, and
A third terminal that outputs an output voltage corresponding to the displacement of the output mechanism with respect to the input voltage,
An arithmetic processing unit that calculates the displacement ratio of the output mechanism based on the output of the sensor, and
A displacement output device including an output circuit that generates a voltage corresponding to the ratio calculated by the arithmetic processing unit with respect to the input voltage and outputs the output voltage to the third terminal. In the displacement output device according to claim 1,
An analog / digital conversion circuit for analog / digital conversion of the magnitude of the input voltage applied to the second terminal and input to the arithmetic processing unit is further provided.
The arithmetic processing unit calculates the magnitude of the output voltage from the output of the sensor and the magnitude of the input voltage input from the analog / digital conversion circuit.
The output circuit
A digital / analog conversion circuit that digitally / analog-converts the magnitude of the output voltage calculated by the arithmetic processing unit, and
Including an analog output circuit that generates a voltage of a magnitude converted by the digital / analog conversion circuit and outputs it as the output voltage.
Displacement output device. In the displacement output device according to claim 2,
A first photocoupler that electrically insulates the analog / digital conversion circuit and the arithmetic processing unit,
It has a second photocoupler that electrically insulates the digital / analog conversion circuit and the arithmetic processing unit.
Displacement output device. In the displacement output device according to claim 1,
A first modulation circuit that outputs a modulated digital signal modulated according to the displacement ratio of the output mechanism, and
Further provided with a second modulation circuit that modulates the voltage applied to the second terminal by the modulated digital signal.
The output circuit
An analog output circuit that smoothes and outputs the voltage output from the second modulation circuit is included.
Displacement output device. In the displacement output device according to claim 4,
The second modulation circuit includes a photocoupler that electrically insulates the arithmetic processing unit and the analog output circuit.
Displacement output device. With the motor
A drive circuit that supplies current to the motor and
An output mechanism that mechanically displaces according to the rotation of the motor,
A sensor that detects the mechanical displacement of the output mechanism and
A control unit that controls the rotation of the motor based on the output of the sensor,
A first terminal connected to a reference potential, a second terminal that applies an arbitrary input voltage to the reference potential, and a third terminal that outputs an output voltage corresponding to the displacement of the output mechanism with respect to the input voltage. Equipped with a displacement output device with terminals
The displacement output device is
The displacement output device according to any one of claims 1 to 5.
Electric actuator. In the electric actuator according to claim 6,
An arithmetic processing unit having an arithmetic processing circuit, a storage device, and an interface is provided.
The arithmetic processing unit is configured to operate as the arithmetic processing unit of the control unit and the displacement output device.
Electric actuator.

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