Brake drive device that drives a mechanical brake device

Abstract

This brake driving device comprises: a positive-side switch for opening / closing a positive-side electrical path between a power source and a mechanical brake device; a negative-side switch for opening / closing a negative-side electrical path between the power source and the mechanical brake device; and a switch control unit for outputting an OFF signal to the positive-side switch and the negative-side switch when braking is to be activated, outputting an ON signal to the positive-side switch and the negative-side switch at the start of brake release when braking is to be released, and while subsequently keeping the braking released, alternately switching between output of a PWM-controlled ON / OFF signal to the positive-side switch and output of the PWM-controlled ON / OFF signal to the negative-side switch at predetermined time intervals.

Description

[Technical Field]

[0001] The present disclosure relates to a brake driving device that drives a mechanical brake device. [Background technology]

[0002] In motor drive devices that drive motors in machines such as industrial robots and machine tools, non-excitation operated mechanical brake devices are widely used to brake rotating motors or to fix stopped motors so that they do not rotate. A switch is connected between the brake coil of the mechanical brake device and the power supply. When the switch is turned on, current flows from the power supply to the brake coil, releasing the brake provided by the mechanical brake device. When the switch is turned off, current is prevented from flowing from the power supply to the brake coil, thereby applying the brake of the mechanical brake device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-119530 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-195287 [Patent Document 3] Japanese Patent Application Laid-Open No. 2007-143311 [Patent Document 4] Japanese Patent Application Publication No. 08-182365 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for a brake drive device that can easily diagnose a fault in a switch provided between a brake coil of a mechanical brake device and a power source, and that can reduce the size and heat generation of the mechanical brake device. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, a brake drive device includes a positive-side switch that, when turned on, closes a positive-side electric circuit between a positive terminal of a power source and a positive terminal of a non-excitation operation type mechanical brake device and, when turned off, opens the positive-side electric circuit; a negative-side switch that, when turned on, closes a negative-side electric circuit between the negative terminal of the power source and the negative terminal of the mechanical brake device and, when turned off, opens the negative-side electric circuit; and a switch control unit that outputs an on signal to turn the positive-side switch and an off signal to turn the negative-side switch on and an off signal to turn the positive-side switch off, wherein the switch control unit outputs an off signal to the positive-side switch and the negative-side switch when activating the brake by the mechanical brake device, and outputs an on signal to the positive-side switch and the negative-side switch when releasing the brake by the mechanical brake device, and thereafter, while the release of the brake by the mechanical brake device is maintained, alternately switches between outputting PWM-controlled on and off signals to the positive-side switch and outputting PWM-controlled on and off signals to the negative-side switch at predetermined intervals. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a circuit diagram showing a brake driving device according to a first embodiment of the present disclosure. [Figure 2] 1 is a cross-sectional view showing the structure of a mechanical brake device controlled by a brake driving device according to the first and second embodiments of the present disclosure, illustrating a state in which a brake is applied to a motor. [Figure 3] 1 is a cross-sectional view showing the structure of a mechanical brake device controlled by a brake driving device according to the first and second embodiments of the present disclosure, showing a state in which the brake applied to the motor is released. [Figure 4] 5 is a timing chart illustrating activation and release of a brake of a mechanical brake device in the brake drive devices according to the first and second embodiments of the present disclosure. [Figure 5]4 is a timing chart illustrating waveforms when the positive-side switch and the negative-side switch of the brake driving device according to the first and second embodiments of the present disclosure are normal. [Figure 6] 4 is a timing chart illustrating waveforms when a short-circuit fault occurs in a positive-side switch of the brake driving device according to the first and second embodiments of the present disclosure. [Figure 7] 4 is a timing chart illustrating waveforms when an open fault occurs in a positive-side switch of the brake driving device according to the first and second embodiments of the present disclosure. [Figure 8] 5 is a flowchart showing an operation related to a fault diagnosis in the brake driving device according to the first embodiment of the present disclosure. [Figure 9] FIG. 4 is a circuit diagram showing a brake driving device according to a second embodiment of the present disclosure. [Figure 10] 10 is a flowchart showing an operation related to a fault diagnosis in a brake driving device according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0007] A brake drive device that drives a mechanical brake device according to an embodiment will be described below with reference to the drawings. In the following description, components having the same or similar functions will be assigned the same reference numerals. Duplicate descriptions of these components may be omitted. Here, "on" of a switch means that the electrical circuit in which the switch is provided is closed; that is, when a switch is turned on, the electrical circuit in which the switch is provided is connected and placed in a closed state. Furthermore, "off" of a switch means that the electrical circuit in which the switch is provided is opened; that is, when a switch is turned off, the electrical circuit in which the switch is provided is interrupted and placed in an open state.

[0008] <Configuration of the brake driving device according to the first embodiment> FIG. 1 is a circuit diagram showing a brake driving device according to a first embodiment of the present disclosure.

[0009] The mechanical brake device 2 controlled by the brake drive device 1 according to the first embodiment of the present disclosure is a non-excitation operated brake device that activates the brake when the brake coil 25 is not excited and no voltage is applied to it, and releases the brake when the brake coil 25 is excited and voltage is applied to it.

[0010] Prior to describing the brake drive device 1 according to the first embodiment of the present disclosure, the structure of a mechanical brake device 2 controlled by the brake drive device 1 will be described with reference to FIGS. 2 and 3. FIG. 2 is a cross-sectional view showing the structure of a mechanical brake device controlled by the brake drive devices according to the first and second embodiments of the present disclosure, illustrating a state in which a brake is applied to a motor. FIG. 3 is a cross-sectional view showing the structure of a mechanical brake device controlled by the brake drive devices according to the first and second embodiments of the present disclosure, illustrating a state in which the brake is released from the motor. The mechanical brake device 2 shown in FIGS. 2 and 3 is applicable to the first and second embodiments.

[0011] As shown in FIGS. 2 and 3 , in the mechanical brake device 2, a friction plate 21 is disposed between an armature 22 and an end plate 23. A hub 32 is splined to the friction plate 21. The hub 32 and the motor shaft 31 are integrated, for example, by shrink fitting, so that the friction plate 21 rotates in conjunction with the rotation of the motor shaft 31. The end plate 23 and a spacer 27 are connected with bolts 28, and the armature 22 is connected to the spacer 27 so as to be movable toward and away from the friction plate 21. A spring 24 and a brake coil 25 are provided within the core 26. As shown in FIG. 2 , in a non-excited state in which no voltage is applied to the brake coil 25, the armature 22 is pressed firmly against the friction plate 21 by the elastic force of the spring 24, and the friction plate 21 is sandwiched between the armature 22 and the end plate 23 and cannot rotate. As a result, the motor shaft 31 connected to the friction plate 21 also cannot rotate, and the motor is braked (brake activated state). 3, in an excited state where a brake current flows through brake coil 25, an electromagnetic force is generated in core 26 that overcomes the elastic force of spring 24 that was pressing armature 22 against friction plate 21, thereby attracting armature 22 to core 26 and releasing friction plate 21 from contact with armature 22 and end plate 23. As a result, friction plate 21, and therefore motor shaft 31, can rotate freely, and the brake on the motor is released (brake released state).

[0012] The mechanical brake device 2 is controlled by a brake driving device 1. As shown in Fig. 1, the brake driving device 1 according to the first embodiment of the present disclosure includes a power supply 10, a positive-side switch 11, a negative-side switch 12, a switch control unit 13, a detection unit 14, a diagnosis unit 15, an alarm output unit 16, and a surge absorber 18. In Fig. 1, only a brake coil 25 of the mechanical brake device 2 is shown.

[0013] Power supply 10 outputs a DC voltage. Power supply 10 is composed of, for example, a rectifier that converts AC voltage to DC voltage, a switching regulator, or a battery. As an example, power supply 10 outputs a DC voltage of 24 V, but may also output a DC voltage of other voltage values ​​(e.g., 15 V, 12 V, 5 V, etc.).

[0014] The positive-side switch 11 and the negative-side switch 12 are each connected in series to the brake coil 25 of the mechanical brake device 2. In the example shown in FIG. 1 , the positive-side switch 11 is provided to open (disconnect) or close (connect) a positive-side electric circuit 43P between the positive terminal 41P of the power source 10 and the positive terminal 42P of the mechanical brake device 2. In addition, the negative-side switch 12 is provided to open (disconnect) or close (connect) a negative-side electric circuit 43N between the negative terminal 41N of the power source 10 and the negative terminal 42N of the mechanical brake device 2. Note that, although one positive-side switch 11 and one negative-side switch 12 are provided in the example shown in FIG. 1 , two or more of each may be provided as a variation. Examples of the positive-side switch 11 and the negative-side switch 12 include FETs, IGBTs, thyristors, GTOs, transistors, and relays. The types of the positive-side switch 11 and the negative-side switch 12 themselves do not limit this embodiment, and switching elements other than those illustrated may also be used.

[0015] The on and off operations of the positive-side switch 11 and the negative-side switch 12 are controlled by a switch control unit 13 .

[0016] That is, the switch control unit 13 transmits an ON signal to the positive-side switch 11 and the negative-side switch 12 to control the ON operation of the positive-side switch 11 and the negative-side switch 12. When the positive-side switch 11 receives an ON signal from the switch control unit 13, it is turned ON to close the positive-side electric circuit 43P between the power supply 10 and the brake coil 25. When the negative-side switch 12 receives an ON signal from the switch control unit 13, it is turned ON to close the negative-side electric circuit 43N between the power supply 10 and the brake coil 25. However, if the positive-side switch 11 or the negative-side switch 12 has an open-circuit fault, that switch will not be turned ON even if it receives an ON signal from the switch control unit 13.

[0017] Furthermore, the switch control unit 13 transmits an OFF signal to the positive-side switch 11 and the negative-side switch 12 to control the positive-side switch 11 and the negative-side switch 12 to turn them OFF. When the positive-side switch 11 receives an OFF signal from the switch control unit 13, the positive-side switch 11 performs an OFF operation to open the positive-side electric circuit 43P between the power supply 10 and the brake coil 25. When the negative-side switch 12 receives an OFF signal from the switch control unit 13, the switch performs an OFF operation to open the negative-side electric circuit 43N between the power supply 10 and the brake coil 25. However, if the positive-side switch 11 or the negative-side switch 12 has a short-circuit fault, the switch does not perform an OFF operation even when it receives an OFF signal from the switch control unit 13.

[0018] Here, the actuation and release of the brake of the mechanical brake device 2 will be described with reference to Fig. 4. Fig. 4 is a timing chart illustrating the actuation and release of the brake of the mechanical brake device in the brake drive device according to the first and second embodiments of the present disclosure. The description of the timing chart shown in Fig. 4 is applicable to the first and second embodiments. The upper part of Fig. 4 shows the on / off state of the positive-side switch 11 or the negative-side switch 12, and the lower part of Fig. 4 shows the average voltage applied to the brake coil 25.

[0019] When the mechanical brake device 2 is to be braked (for example, from the start to time t1), the switch control unit 13 outputs an OFF signal to the positive-side switch 11 and the negative-side switch 12. Upon receiving the OFF signal from the switch control unit 13, the positive-side switch 11 and the negative-side switch 12 turn OFF and open the positive-side electric circuit 43P and the negative-side electric circuit 43N between the power supply 10 and the brake coil 25. This cuts off the current flowing from the power supply 10 to the brake coil 25, causing the average voltage of the brake coil 25 to become 0 (zero), and the electromagnetic force generated in the core 26 disappears. The elastic force of the spring 24 overcomes the electromagnetic force generated in the core 26, so that the armature 22 is pressed firmly against the friction plate 21, and the mechanical brake device 2 is braked (brake activated state).

[0020] Furthermore, when releasing the brake applied by the mechanical brake device 2, the switch control unit 13 performs the following series of controls. First, the switch control unit 13 outputs an ON signal to the positive-side switch 11 and the negative-side switch 12 at time t1, which is the start of brake release. Upon receiving the ON signal from the switch control unit 13, the positive-side switch 11 and the negative-side switch 12 close the positive-side electric circuit 43P and the negative-side electric circuit 43N. As a result, current flows from the power source 10 to the brake coil 25, the average voltage of the brake coil 25 becomes V1, and an electromagnetic force is generated in the core 26 that overcomes the elastic force of the spring 24 that had been pressing the armature 22 against the friction plate 21. This electromagnetic force attracts the armature 22 to the core 26, and the friction plate 21 is released from contact with the armature 22 and the end plate 23. As a result, the friction plate 21, and therefore the motor shaft 31, become free to rotate, and the brake on the motor is released (brake released state).

[0021] Once the brake of the mechanical brake device 2 is released, even an electromagnetic force slightly smaller than the electromagnetic force generated in the core 26 at the start of brake release can overcome the elastic force of the spring 24. Therefore, at time t2, in order to maintain the brake release state, the switch control unit 13 alternately switches the output of the PWM (Pulse Width Modulation) - controlled on - signal and off - signal for the positive - side switch 11 and the output of the PWM - controlled on - signal and off - signal for the negative - side switch 12 at predetermined time intervals. In the upper part of FIG. 4, as an example, the on - off state of one of the positive - side switch 11 or the negative - side switch 12 is shown. While the switch control unit 13 outputs the PWM - controlled on - signal and off - signal for the positive - side switch 11, it outputs an on - signal for the negative - side switch 12. Also, while the switch control unit 13 outputs the PWM - controlled on - signal and off - signal for the negative - side switch 12, it outputs an on - signal for the positive - side switch 11. Even after time t2 when the on - off operation of the positive - side switch 11 and the negative - side switch 12 is PWM - controlled, current flows from the power supply 10 to the brake coil 25, but its magnitude becomes smaller than the magnitude of the current from time t1 to time t2. Thus, the average voltage of the brake coil 25 becomes V2 (<V1), and the heat generation of the mechanical brake device 2 is reduced. Also, there is no problem even if the mechanical brake device 2 is miniaturized. Set the duty ratio used for PWM control to a magnitude such that an electromagnetic force that can overcome the elastic force of the spring 24 is generated. By setting the duty ratio in this way, the friction plate 21 can be maintained in a state of being released from contact with the armature 22 and the end plate 23, so that the brake release state can be maintained. As an example of the duty ratio used for PWM control, for example, 50% may be set, but the numerical value given here is only an example, and other numerical values may also be used.

[0022] Although details will be described later, while the switch control unit 13 switches between PWM control of the positive side switch 11 and PWM control of the negative side switch 12, the diagnosis unit 15 performs fault diagnosis on the positive side switch 11 and the negative side switch 12. Therefore, in order to realize a Safe Brake Control (SBC) function compliant with IEC / EN61800-5-2, the switch control unit 13 may switch between outputting PWM-controlled ON and OFF signals to the positive side switch 11 and outputting PWM-controlled ON and OFF signals to the negative side switch 12, for example, approximately every 500 milliseconds. The numerical values ​​given here are merely examples, and other numerical values ​​may be used.

[0023] Returning to Fig. 1 for explanation, the surge absorber 18 is connected between the positive and negative terminals of the brake coil 25 so as to be connected in parallel to the mechanical brake device 2. The surge absorber 18 removes momentary high voltages such as opening and closing surges and noise of the switches 11 and 12.

[0024] The detection unit 14 detects electrical information, which is at least one of the voltage applied to the brake coil 25 of the mechanical brake device 2 and the current flowing through the brake coil 25. The electrical information detected by the detection unit 14 is sent to the diagnosis unit 15. Note that, hereinafter, the voltage applied to the brake coil 25 may be referred to as the "brake coil voltage," and the current flowing through the brake coil 25 may be referred to as the "brake coil current."

[0025] The diagnosing unit 15 diagnoses whether or not there is a fault in the positive-side switch 11 and the negative-side switch 12 based on the electrical information detected by the detecting unit 14 while the switch control unit 13 alternately switches between outputting PWM-controlled on and off signals to the positive-side switch 11 and outputting PWM-controlled on and off signals to the negative-side switch 12 at predetermined time intervals.

[0026] The alarm output unit 16 outputs an alarm when the diagnosis unit 15 determines that at least one of the positive-side switch 11 and the negative-side switch 12 is faulty.

[0027] Based on the output of the alarm by the alarm output unit 16, the diagnosis result by the diagnosing unit 15 may be displayed on, for example, a display device (not shown). Examples of the display device include a standalone display device, a display device attached to the brake drive device 1 or a motor drive device including the same, and a display device attached to a personal computer or a mobile terminal. For example, the display device displays, for example, "The positive side switch is normal," "The negative side switch is normal," "The positive side switch is faulty," or "The negative side switch is faulty." The above-mentioned display example by the display device is merely an example, and other expressions or pictures may be used to display "The positive side switch is normal," "The negative side switch is normal," "The positive side switch is faulty," or "The negative side switch is faulty." If the positive side switch or the negative side switch is faulty, a more detailed description of the fault, such as whether it is a short-circuit fault or an open-circuit fault, may be displayed.

[0028] Based on the output of the alarm by the alarm output unit 16, the diagnosis result by the diagnosis unit 15 may be output by an audio device (not shown) that emits a sound such as a voice, a speaker, a buzzer, or a chime. For example, a tone, a scale, a rhythm, or a melody may be set so that the differences between "positive side switch is normal," "negative side switch is normal," "positive side switch is faulty," and "negative side switch is faulty" can be distinguished. In addition, the audio device may be silent when "positive side switch and negative side switch are normal," and emit a sound only when "positive side switch is faulty" or "negative side switch is faulty." If the positive side switch or negative side switch is faulty, the audio device may emit a sound that identifies a more detailed fault, such as a short circuit fault or an open circuit fault.

[0029] The results of the diagnosis by the diagnosis unit 15 may be printed out on paper or the like using a printer and displayed.

[0030] Although examples of notifying the operator of the diagnosis results by the diagnosing unit 15 have been described above, these may be realized by appropriately combining them. In addition, each time a diagnosis result is obtained by the diagnosing unit 15, it may be stored and accumulated in memory, and made into a database, which may be used for failure prediction and preventive maintenance.

[0031] The worker can quickly and reliably grasp the states of the positive side switch 11 and the negative side switch 12 of the brake drive device 1 based on the notified diagnosis result by the diagnosis unit 15. Therefore, if the worker finds from the diagnosis result by the diagnosis unit 15 that the positive side switch 11 or the negative side switch 12 is faulty, the worker can take action such as replacing or repairing the positive side switch 11 or the negative side switch 12, for example.

[0032] The brake drive device 1 or a motor drive device including the same includes at least one processor, which is an arithmetic processing device. Examples of the arithmetic processing device include an IC, an LSI, a CPU, an MPU, and a DSP. The arithmetic processing device includes a switch control unit 13, a detection unit 14, a diagnosis unit 15, an alarm output unit 16, and other processing circuits. Each of these units included in the arithmetic processing device is a functional module implemented by a program executed on the processor. For example, if the switch control unit 13, the detection unit 14, the diagnosis unit 15, the alarm output unit 16, and other processing circuits are implemented in a program format, the functions of each unit can be realized by operating the arithmetic processing device in accordance with the program. The programs for executing the processes of the switch control unit 13, the detection unit 14, the diagnosis unit 15, the alarm output unit 16, and other processing circuits may be provided in a form recorded on a computer-readable recording medium such as a semiconductor memory, a magnetic recording medium, or an optical recording medium. Alternatively, the switch control unit 13, the detection unit 14, the diagnosis unit 15, the alarm output unit 16, and other processing circuits may be implemented as semiconductor integrated circuits in which programs for implementing the functions of each unit are written.

[0033] The brake drive device 1 or a motor drive device including the same is provided with at least one memory serving as a storage device. Examples of the memory include electrically erasable and recordable nonvolatile memories such as EEPROM (registered trademark), or high-speed read / write random access memories such as DRAM and SRAM. The storage device may also have a configuration such as an HDD or SSD. The memory may store programs for operating the switch control unit 13, the detection unit 14, the diagnosis unit 15, the alarm output unit 16, and other processing circuits. The memory also stores electrical information acquired by the detection unit 14. The memory also stores diagnostic results from the diagnosis unit 15. The memory also stores various data related to the brake drive device 1 or a motor drive device including the same.

[0034] <Operation of the brake driving device according to the first embodiment> The operation of the brake driving device according to the first embodiment will be described with reference to the timing charts shown in Figs. 5 to 7. The explanations regarding the timing charts shown in Figs. 5 to 7 are applicable to the first and second embodiments. Figs. 5 to 7 show, from top to bottom, an on signal and an off signal applied to the positive-side switch 11, an on signal and an off signal applied to the negative-side switch 12, the voltage of the brake coil 25 of the mechanical brake device 2, and the current flowing through the brake coil 25 of the mechanical brake device 2. Also, Figs. 5 to 7 show, as an example, a time period from the start to time t 11 The brake operation process is executed until time t 11 The brake release process starts at time t 11 After that, the brake release state is maintained.

[0035] FIG. 5 is a timing chart illustrating waveforms when the positive-side switch and the negative-side switch of the brake driving device according to the first and second embodiments of the present disclosure are normal.

[0036] When the positive-side switch 11 and the negative-side switch 12 are normal, the positive-side switch 11 and the negative-side switch 12 perform an on operation and an off operation in accordance with an on signal and an off signal output from the switch control unit 13 .

[0037] When the mechanical brake device 2 is to be braked (for example, from the start to time t 11 The positive-side switch 11 and the negative-side switch 12 output an OFF signal to the positive-side switch 11 and the negative-side switch 12. Upon receiving the OFF signal from the switch control unit 13, the positive-side switch 11 and the negative-side switch 12 turn OFF and open the positive-side electric circuit 43P and the negative-side electric circuit 43N between the power supply 10 and the brake coil 25. This cuts off the current flowing from the power supply 10 to the brake coil 25, so the voltage and current of the brake coil 25 become 0 (zero). Because no electromagnetic force is generated in the brake coil 25, the elastic force of the spring 24 presses the armature 22 firmly against the friction plate 21, and the mechanical brake device 2 applies the brake.

[0038] time t 11 The brake release process is started at time t 11 2. The positive-side switch 11 and the negative-side switch 12 receive an ON signal from the switch control unit 13 and close the positive-side electric circuit 43P and the negative-side electric circuit 43N. As a result, the voltage of the brake coil 25 becomes V1, a current (maximum value is I1) flows from the power supply 10 to the brake coil 25, and an electromagnetic force is generated in the core 26 that overcomes the elastic force of the spring 24 that had been pressing the armature 22 against the friction plate 21. This electromagnetic force attracts the armature 22 to the core 26, and the friction plate 21 is released from contact with the armature 22 and the end plate 23. As a result, the friction plate 21 and therefore the motor shaft 31 can rotate freely, and the brake on the motor is released.

[0039] time t 12Thereafter, in order to maintain the brake release state, the switch control unit 13 alternately switches between outputting PWM-controlled ON and OFF signals to the positive-side switch 11 and outputting PWM-controlled ON and OFF signals to the negative-side switch 12 every predetermined time T. The predetermined time T for PWM control is set to, for example, approximately 500 milliseconds, but this value is merely an example and other values ​​may be used. The predetermined time T may be stored in a rewritable storage unit (not shown) and rewritable by an external device. This allows the predetermined time T to be changed to an appropriate value as needed, even after it has been set.

[0040] For example, by setting a longer predetermined time T for PWM control for one of the positive-side switch 11 and the negative-side switch 12, whichever has a higher failure probability, it is possible to focus on monitoring failures of the switch with the higher failure probability. Also, by setting a longer predetermined time T for PWM control for one of the positive-side switch 11 and the negative-side switch 12, which has better heat dissipation, it is possible to suppress heat generation due to the switching operation of the switch with better heat dissipation.

[0041] To maintain the brake release state, 12 From time t 13 Until time t 14 From time t 15 Between t and t 16 From time t 17During this time, the switch control unit 13 outputs PWM-controlled ON and OFF signals to the positive-side switch 11 and outputs an ON signal to the negative-side switch 12. The positive-side switch 11, which receives the PWM-controlled ON and OFF signals from the switch control unit 13, performs ON / OFF operations to close and open the positive-side electrical circuit 43P between the power supply 10 and the brake coil 25. Furthermore, the negative-side switch 12, which receives an ON signal from the switch control unit 13, closes the negative-side electrical circuit 43N. This causes the voltage of the brake coil 25 to oscillate between V1 and 0 (zero). Furthermore, an oscillating current smaller than the maximum value I1 of the brake coil current flows from the power supply 10 to the brake coil 25. The duty ratio used in the PWM control is set to a value sufficient to generate an electromagnetic force that overcomes the elastic force of the spring 24, thereby maintaining a brake-released state in which the friction plate 21 is released from contact with the armature 22 and the end plate 23.

[0042] To maintain the brake release state, 13 From time t 14 Until time t 15 From time t 16 Between t and t 17 Thereafter, the switch control unit 13 outputs an ON signal to the positive-side switch 11 and PWM-controlled ON and OFF signals to the negative-side switch 12. Upon receiving the ON signal from the switch control unit 13, the positive-side switch 11 closes the positive-side electrical circuit 43P. Furthermore, upon receiving the PWM-controlled ON and OFF signals from the switch control unit 13, the negative-side switch 12 performs ON / OFF operation to close and open the negative-side electrical circuit 43N between the power supply 10 and the brake coil 25. This causes the voltage of the brake coil 25 to oscillate between V1 and 0 (zero). Furthermore, an oscillatory current smaller than the maximum value I1 of the brake coil current flows from the power supply 10 to the brake coil 25. The duty ratio used in the PWM control is set to a value large enough to generate an electromagnetic force that overcomes the elastic force of the spring 24, thereby maintaining a brake-released state in which the friction plate 21 is released from contact with the armature 22 and the end plate 23.

[0043] In this way, the brake release state is maintained until time t 12 Thereafter, the switch control unit 13 alternately switches between outputting PWM-controlled on and off signals to the positive-side switch 11 and outputting PWM-controlled on and off signals to the negative-side switch 12 at predetermined time intervals T. When the positive-side switch 11 and the negative-side switch 12 are normal, the positive-side switch 11 and the negative-side switch 12 perform on and off operations in accordance with the PWM-controlled on and off signals alternately sent to the positive-side switch 11 and the negative-side switch 12, causing the voltage and current of the brake coil 25 to vary in an oscillatory manner. The detection unit 14 detects the voltage applied to the brake coil 25 of the mechanical brake device 2 or the current flowing through the brake coil 25 as electrical information. The diagnosis unit 15 determines whether or not the switch control unit 13 is performing alternate switching between PWM control for on-off control of the positive-side switch 11 and PWM control for on-off control of the negative-side switch 12 at predetermined time intervals. 12 If the electrical information detected by the detector 14 thereafter constantly changes in an oscillatory manner, it is determined that both the positive-side switch 11 and the negative-side switch 12 are normal.

[0044] FIG. 6 is a timing chart illustrating waveforms when a short-circuit fault occurs in the positive-side switch of the brake driving device according to the first and second embodiments of the present disclosure.

[0045] For example, if the positive-side switch 11 has a short-circuit fault and the negative-side switch 12 is normal, the positive-side switch 11 remains in an on state regardless of the on and off signals output from the switch control unit 13. On the other hand, the normal negative-side switch 12 performs on and off operations in accordance with the on and off signals output from the switch control unit 13.

[0046] When the mechanical brake device 2 is to be braked (for example, from the start to time t 11The positive-side switch 11 and the negative-side switch 12 output an OFF signal to the positive-side switch 11 and the negative-side switch 12. The positive-side switch 11, which has a short-circuit fault, does not turn OFF even when it receives an OFF signal from the switch control unit 13, and keeps the positive-side electric circuit 43P between the power source 10 and the brake coil 25 closed. On the other hand, the negative-side switch 12, which receives an OFF signal from the switch control unit 13, turns OFF and opens the negative-side electric circuit 43N between the power source 10 and the brake coil 25. Because the negative-side electric circuit 43N between the power source 10 and the brake coil 25 is open, the current flowing from the power source 10 to the brake coil 25 is cut off, and therefore the voltage and current of the brake coil 25 become 0 (zero). Because no electromagnetic force is generated in the brake coil 25, the elastic force of the spring 24 presses the armature 22 firmly against the friction plate 21, and the mechanical brake device 2 applies brake force.

[0047] time t 11 The brake release process is started at time t 11 2. The positive-side switch 11 and the negative-side switch 12 receive an ON signal from the switch control unit 13 and close the positive-side electric circuit 43P and the negative-side electric circuit 43N. As a result, the voltage of the brake coil 25 becomes V1, a current (maximum value is I1) flows from the power supply 10 to the brake coil 25, and an electromagnetic force is generated in the core 26 that overcomes the elastic force of the spring 24 that had been pressing the armature 22 against the friction plate 21. This electromagnetic force attracts the armature 22 to the core 26, and the friction plate 21 is released from contact with the armature 22 and the end plate 23. As a result, the friction plate 21 and therefore the motor shaft 31 can rotate freely, and the brake on the motor is released.

[0048] time t 12 Thereafter, in order to maintain the brake release state, the switch control unit 13 alternately switches between outputting PWM-controlled on and off signals to the positive side switch 11 and outputting PWM-controlled on and off signals to the negative side switch 12 every predetermined time T.

[0049] That is, at time t 12 From time t 13 Until time t 14 From time t 15 Between t and t 16 From time t 17 During this period, the switch control unit 13 outputs PWM-controlled ON and OFF signals to the positive-side switch 11, and outputs an ON signal to the negative-side switch 12. The positive-side switch 11, which has received the PWM-controlled ON and OFF signals from the switch control unit 13, has a short-circuit fault, so the positive-side electric circuit 43P between the power supply 10 and the brake coil 25 remains closed. Furthermore, the negative-side switch 12, which has received an ON signal from the switch control unit 13, closes the negative-side electric circuit 43N. Therefore, during this period, the positive-side switch 11 and the negative-side switch 12 are in a state where the positive-side electric circuit 43P is closed at time t 11 From time t 12 As in the case up to this point, both switches are closed, the voltage of brake coil 25 becomes V1, and a waveform F1 appears in which a current (maximum value I1) flows from power supply 10 to brake coil 25. As explained with reference to FIG. 5, if positive-side switch 11 were normal, the voltage of brake coil 25 would oscillate between V1 and 0 (zero) in response to the PWM-controlled on and off signals, and an oscillating current smaller than the maximum value I1 of the brake coil current would flow from power supply 10 to brake coil 25. However, because the positive-side switch 11 is short-circuited, a waveform F1 appears in which a constant voltage V1 is applied to brake coil 25 and a constant current I1 flows through brake coil 25. However, because an electromagnetic force that overcomes the elastic force of spring 24 is generated, the brake release state in which friction plate 21 is released from contact with armature 22 and end plate 23 can be maintained.

[0050] time t 13 From time t 14 Until time t 15 From time t 16 Between t and t 17Thereafter, the switch control unit 13 outputs an ON signal to the positive-side switch 11 and outputs PWM-controlled ON and OFF signals to the negative-side switch 12. Upon receiving the ON signal from the switch control unit 13, the positive-side switch 11 closes the positive-side electrical circuit 43P. Furthermore, upon receiving the PWM-controlled ON and OFF signals from the switch control unit 13, the negative-side switch 12 performs ON / OFF operation to close and open the negative-side electrical circuit 43N between the power supply 10 and the brake coil 25. As a result, the voltage of the brake coil 25 oscillates between V1 and 0 (zero), and an oscillating current smaller than the maximum value I1 of the brake coil current flows from the power supply 10 to the brake coil 25. The duty ratio used in the PWM control is set to a value sufficient to generate an electromagnetic force that overcomes the elastic force of the spring 24, thereby maintaining a brake-released state in which the friction plate 21 is released from contact with the armature 22 and the end plate 23.

[0051] In this way, when the positive-side switch 11 has a short-circuit fault, the output of PWM-controlled ON and OFF signals to the positive-side switch 11 and the output of PWM-controlled ON and OFF signals to the negative-side switch 12 are alternately switched every predetermined time T until time t 12 After that, a waveform F1 appears in which a constant voltage V1 is applied to the brake coil 25 and a constant current I1 flows through the brake coil 25. Therefore, the diagnosis unit 15 performs a PWM control to detect the current flowing through the positive-side switch 11 while the PWM-controlled ON and OFF signals are being output (at time t 12 From time t 13 Until time t 14 From time t 15 Between t and t 16 From time t 17If the electrical information detected by the detection unit 14 is a substantially constant value equal to or greater than a predetermined first threshold during the period from the start of the test to the end of the test, the positive-side switch 11 is determined to have a short-circuit fault. Here, if the electrical information is voltage, the first threshold is set to a value somewhat lower (e.g., about 10% to 20% lower) than the maximum voltage value that the brake coil voltage can assume, and if the electrical information is current, the first threshold is set to a value somewhat lower (e.g., about 10% to 20% lower) than the maximum current value that the brake coil current can assume. The numerical examples shown here are merely examples, and other values ​​may also be used. The first threshold may be stored in a rewritable storage unit (not shown) and rewritable by an external device. In this case, even after the first threshold has been set, it can be changed to an appropriate value as needed.

[0052] 6 has been described above by taking as an example a case where the positive-side switch 11 has a short-circuit fault. For the explanation of a short-circuit fault in the negative-side switch 12, the explanation of FIG. 6 is applied with the positive-side switch 11 and the negative-side switch 12 interchanged. That is, the diagnosing unit 15 performs PWM control to turn on and off the negative-side switch 12 (from time t 13 From time t 14 Until time t 15 From time t 16 Between t and t 17 In the following steps, if the electrical information detected by the detection unit 14 is a substantially constant value equal to or greater than a first threshold value that is specified in advance, it is determined that the negative-side switch 12 has a short-circuit fault.

[0053] FIG. 7 is a timing chart illustrating waveforms when an open fault occurs in the positive-side switch of the brake driving device according to the first and second embodiments of the present disclosure.

[0054] For example, if the positive-side switch 11 has an open fault and the negative-side switch 12 is normal, the positive-side switch 11 remains in an off state regardless of the on and off signals output from the switch control unit 13. On the other hand, the normal negative-side switch 12 performs on and off operations in accordance with the on and off signals output from the switch control unit 13.

[0055] When the mechanical brake device 2 is to be braked (for example, from the start to time t 11 The positive-side switch 11 (up to the switch control unit 13) outputs an OFF signal to the positive-side switch 11 and the negative-side switch 12. Because the positive-side switch 11 has an open fault, the positive-side electric circuit 43P between the power supply 10 and the brake coil 25 remains open. Meanwhile, the negative-side switch 12, which has received an OFF signal from the switch control unit 13, performs an OFF operation and opens the negative-side electric circuit 43N between the power supply 10 and the brake coil 25. Because the negative-side electric circuit 43N between the power supply 10 and the brake coil 25 is open, the current flowing from the power supply 10 to the brake coil 25 is cut off, and therefore the voltage and current of the brake coil 25 become 0 (zero). Because no electromagnetic force is generated in the brake coil 25, the elastic force of the spring 24 presses the armature 22 firmly against the friction plate 21, and the mechanical brake device 2 applies brake force.

[0056] time t 11 The brake release process is started at time t 1125. The switch control unit 13 outputs an ON signal to the positive-side switch 11 and the negative-side switch 12. The negative-side switch 12, which has received the ON signal from the switch control unit 13, closes the negative-side electrical circuit 43N between the power supply 10 and the brake coil 25. However, because the positive-side switch 11 has an open fault, the positive-side switch 11 does not turn ON, and the positive-side electrical circuit 43P between the power supply 10 and the brake coil 25 remains open. Therefore, the current flowing from the power supply 10 to the brake coil 25 is cut off, and the voltage and current of the brake coil 25 become 0 (zero). Because no electromagnetic force is generated in the brake coil 25, the elastic force of the spring 24 presses the armature 22 firmly against the friction plate 21, and the mechanical brake device 2 remains braked.

[0057] time t 12 Thereafter, the switch control unit 13 alternately switches between outputting PWM-controlled on and off signals to the positive-side switch 11 and outputting PWM-controlled on and off signals to the negative-side switch 12 every predetermined time T.

[0058] That is, at time t 12 From time t 13 Until time t 14 From time t 15 Between t and t 16 From time t 17 During this period, the switch control unit 13 outputs PWM-controlled on and off signals to the positive-side switch 11, and outputs an on signal to the negative-side switch 12. The positive-side switch 11, which has received the PWM-controlled on and off signals from the switch control unit 13, does not turn on because it has an open fault, and the positive-side electrical circuit 43P between the power supply 10 and the brake coil 25 remains open. Furthermore, the negative-side switch 12, which has received an on signal from the switch control unit 13, closes the negative-side electrical circuit 43N between the power supply 10 and the brake coil 25. Therefore, during this period, the positive-side switch 11 and the negative-side switch 12 are in an open state, and a waveform F2 appears in which the voltage and current of the brake coil 25 are both zero.

[0059] time t 13From time t 14 Until time t 15 From time t 16 Between t and t 17 Thereafter, the switch control unit 13 outputs an ON signal to the positive-side switch 11, and outputs PWM-controlled ON and OFF signals to the negative-side switch 12. The negative-side switch 12, which has received the PWM-controlled ON and OFF signals from the switch control unit 13, performs ON / OFF operation to close and open the negative-side electric circuit 43N between the power supply 10 and the brake coil 25. However, because the positive-side switch 11 has an open fault, the positive-side electric circuit 43P between the power supply 10 and the brake coil 25 remains open. Therefore, during this time, the positive-side switch 11 and the negative-side switch 12 are in an open state, and a waveform F2 appears in which the voltage and current of the brake coil 25 are both zero.

[0060] As explained with reference to FIG. 5, if the positive-side switch 11 is normal, the voltage of the brake coil 25 should fluctuate between V1 and 0 (zero) in response to the PWM-controlled on and off signals, and an oscillatory current smaller than the maximum value I1 of the brake coil current should flow from the power supply 10 to the brake coil 25. However, since the positive-side switch 11 has an open-circuit fault, a waveform F2 in which both the voltage and current of the brake coil 25 are 0 always appears. Therefore, the diagnosis unit 15 performs a PWM-controlled on-signal and off-signal output operation while the switch control unit 13 is outputting the PWM-controlled on-signal and off-signal to the positive-side switch 11 (time t 12 From time t 13 Until time t 14 From time t 15 Between t and t 16 From time t 17 and while the PWM-controlled ON and OFF signals are being output to the negative-side switch 12 (time t 13 From time t 14 Until time t 15 From time t 16 Between t and t 17In both of the above (hereinafter), if the electrical information detected by the detection unit 14 is a substantially constant value equal to or less than a predetermined second threshold, it is determined that at least one of the positive-side switch 11 and the negative-side switch 12 has an open fault. Here, the second threshold is set to a positive value near 0 volts if the electrical information is voltage, and is set to a positive value near 0 amperes if the electrical information is current. The numerical examples shown here are merely examples, and other values ​​may also be used. Note that the second threshold may be stored in a rewritable storage unit (not shown) and rewritable by an external device. In this way, even after the second threshold has been set, it can be changed to an appropriate value as needed.

[0061] 7 has been described above taking as an example a case where an open fault occurs in the positive-side switch 11. For an open fault in the negative-side switch 12, the same description as in FIG. 7 applies except that the positive-side switch 11 and the negative-side switch 12 are interchanged.

[0062] 7, when the negative-side switch 12 has an open-circuit fault, the waveform F2 in which the voltage and current of the brake coil 25 both become zero always appears. That is, when the positive-side switch 11 has an open-circuit fault and when the negative-side switch 12 has an open-circuit fault, the waveform F2 in which the voltage and current of the brake coil 25 both become zero appears. Therefore, it is impossible to distinguish from the waveform F2 in which the voltage and current of the brake coil 25 both become zero whether the positive-side switch 11 has an open-circuit fault, the negative-side switch 12 has an open-circuit fault, or both the positive-side switch 11 and the negative-side switch 12 have an open-circuit fault. When the electrical information detected by the detection unit 14 is a substantially constant value that is equal to or less than a predetermined second threshold, the diagnosis unit 15 determines that at least one of the positive-side switch 11 and the negative-side switch 12 has an open-circuit fault.

[0063] 8 is a flowchart showing an operation related to fault diagnosis in the brake drive device according to the first embodiment of the present disclosure. Here, as an example, the electrical information detected by the detection unit 14 is the voltage applied to the brake coil 25. If the electrical information detected by the detection unit 14 is the current flowing through the brake coil 25, the flowchart shown in FIG. 8 can be applied by replacing "the voltage applied to the brake coil 25" with "the current flowing through the brake coil 25."

[0064] In step S101, the switch control unit 13 and the diagnosis unit 15 determine whether the mechanical brake device 2 is in a brake release state. If it is determined that the mechanical brake device 2 is in a brake applied state, the process returns to step S101. When it is determined that the mechanical brake device 2 is in a brake release state, the switch control unit 13 first outputs an ON signal to the positive side switch 11 and the negative side switch 12 at the start of brake release, and then proceeds to step S102.

[0065] In step S102, the switch control unit 13 alternately switches between outputting PWM-controlled on and off signals to the positive-side switch 11 and outputting PWM-controlled on and off signals to the negative-side switch 12 at predetermined time intervals. While the switch control unit 13 is outputting PWM-controlled on and off signals to the positive-side switch 11, it outputs an on signal to the negative-side switch 12. Moreover, while the switch control unit 13 is outputting PWM-controlled on and off signals to the negative-side switch 12, it outputs an on signal to the positive-side switch 11.

[0066] In step S103, the detection unit 14 detects the brake coil voltage. Information about the detected brake coil voltage is sent to the diagnosis unit 15.

[0067] In step S104, the diagnosis unit 15 determines whether the voltage of the brake coil 25 is a substantially constant value equal to or greater than the first threshold value.

[0068] If it is determined in step S104 that the voltage applied to the brake coil 25 is a substantially constant value equal to or greater than the first threshold, the process proceeds to S106. In step S106, if it is determined in step S104 that the brake coil voltage detected by the detection unit 14 while PWM-controlled on and off signals are being output to the positive-side switch 11 is a substantially constant value equal to or greater than the first threshold, the diagnosis unit 15 determines that the positive-side switch 11 has a short-circuit fault. Also, in step S106, if it is determined in step S104 that the brake coil voltage detected by the detection unit 14 while PWM-controlled on and off signals are being output to the negative-side switch 12 is a substantially constant value equal to or greater than the first threshold, the diagnosis unit 15 determines that the negative-side switch 12 has a short-circuit fault. After step S106, the process returns to step S101.

[0069] If it is not determined in step S104 that the voltage applied to the brake coil 25 is a substantially constant value equal to or greater than the first threshold, the process proceeds to step S105. In step S105, the diagnosis unit 15 determines whether the voltage of the brake coil 25 is a substantially constant value equal to or less than the second threshold.

[0070] If it is determined in step S105 that the voltage of the brake coil 25 is a substantially constant value equal to or less than the second threshold, the process proceeds to step S108. In step S108, the diagnosis unit 15 determines that an open fault has occurred in at least one of the positive-side switch 11 and the negative-side switch 12. After step S108, the process returns to step S101.

[0071] If it is not determined in step S105 that the voltage of the brake coil 25 is a substantially constant value equal to or less than the second threshold, the process proceeds to step S107. In step S107, the diagnosis unit 15 determines that both the positive-side switch 11 and the negative-side switch 12 are normal. After step S107, the process returns to step S101.

[0072] The order of the processing in step S104 and the processing in step S105 may be reversed.

[0073] According to the first embodiment of the present disclosure, while PWM control is being performed on the positive side switch 11 and the negative side switch 12 in the brake release state, the diagnosis unit 15 can easily diagnose failures in the positive side switch 11 and the negative side switch 12. Furthermore, by performing PWM control on the positive side switch 11 and PWM control on the negative side switch in the brake release state, the brake release state is maintained with less power than when the brake release starts, so that the mechanical brake device 2 can be made smaller and generate less heat.

[0074] <Configuration of the brake driving device according to the second embodiment> FIG. 9 is a circuit diagram showing a brake driving device according to the second embodiment of the present disclosure.

[0075] 1 to 8, the diagnosis unit 15 performs diagnostic processing based on the electrical information detected by the detection unit 14. In the second embodiment, a display unit 17 that displays the electrical information detected by the detection unit 14 is provided instead of the diagnosis unit 15 and alarm output unit 16 in FIG.

[0076] 9, a brake driving device 1 according to the second embodiment of the present disclosure includes a power supply 10, a positive-side switch 11, a negative-side switch 12, a switch control unit 13, a detection unit 14, a display unit 17, and a surge absorber 18. In FIG. 9, of the mechanical brake device 2 controlled by the brake driving device 1, only a brake coil 25 is shown.

[0077] The mechanical brake device 2, power supply 10, positive side switch 11, negative side switch 12, switch control unit 13, detection unit 14, diagnosis unit 15, and surge absorber 18 are as described with reference to Figures 1 to 9 in the first embodiment.

[0078] Display unit 17 displays electrical information detected by detection unit 14 while switch control unit 13 alternately switches at predetermined time intervals between outputting PWM-controlled on and off signals to positive-side switch 11 and outputting PWM-controlled on and off signals to negative-side switch 12. Examples of display unit 17 include a standalone display device, a display device attached to brake drive device 1 or a motor drive device including the same, and a display device attached to a personal computer or a mobile terminal.

[0079] <Operation of the brake driving device according to the second embodiment> The explanations regarding the timing charts shown in FIGS. 5 to 7 are also applicable to the second embodiment.

[0080] 10 is a flowchart showing an operation related to fault diagnosis in a brake drive device according to a second embodiment of the present disclosure. Here, as an example, the electrical information detected by the detection unit 14 is the voltage applied to the brake coil 25. If the electrical information detected by the detection unit 14 is the current flowing through the brake coil 25, the flowchart shown in FIG. 10 can be applied by replacing "the voltage applied to the brake coil 25" with "the current flowing through the brake coil 25."

[0081] In step S201, the switch control unit 13 and the diagnosis unit 15 determine whether the mechanical brake device 2 is in a brake release state. If it is determined that the mechanical brake device 2 is in a brake applied state, the process returns to step S201. When it is determined that the mechanical brake device 2 is in a brake release state, the switch control unit 13 first outputs an ON signal to the positive side switch 11 and the negative side switch 12 at the start of brake release, and then proceeds to step S102.

[0082] In step S202, the switch control unit 13 alternately switches between outputting PWM-controlled on and off signals to the positive-side switch 11 and outputting PWM-controlled on and off signals to the negative-side switch 12 at predetermined time intervals. While the switch control unit 13 is outputting PWM-controlled on and off signals to the positive-side switch 11, it outputs an on signal to the negative-side switch 12. Moreover, while the switch control unit 13 is outputting PWM-controlled on and off signals to the negative-side switch 12, it outputs an on signal to the positive-side switch 11.

[0083] In step S203, the detection unit 14 detects the brake coil voltage. Information about the detected brake coil voltage is sent to the display unit 17.

[0084] In step S203, the display unit 17 displays the brake coil voltage.

[0085] 4 to 6, the display unit 17 displays the brake coil voltage detected by the detection unit 14 while the switch control unit 13 alternately switches at predetermined time intervals between outputting PWM-controlled on and off signals to the positive-side switch 11 and outputting PWM-controlled on and off signals to the negative-side switch 12. By visually checking the contents displayed on the display unit 17, the worker can determine whether the positive-side switch 11 and the negative-side switch 12 are normal, whether the positive-side switch 11 has a short-circuit fault, whether the negative-side switch has a short-circuit fault, or whether at least one of the positive-side switch 11 and the negative-side switch has an open-circuit fault.

[0086] According to the second embodiment of the present disclosure, an operator can easily diagnose failures in the positive side switch 11 and the negative side switch 12 based on the display content on the display unit 17 regarding electrical information related to the brake coil 25 of the mechanical brake device 2 while PWM control of the positive side switch 11 and PWM control of the negative side switch are being performed in the brake release state. Furthermore, by performing PWM control of the positive side switch 11 and PWM control of the negative side switch in the brake release state, the brake release state is maintained with less power than when the brake release started, and therefore the mechanical brake device 2 can be made smaller and generate less heat.

[0087] <Achieving fault diagnosis while miniaturizing and reducing heat generation in mechanical brake devices> According to the first and second embodiments of the present disclosure, by performing PWM control on the positive side switch 11 and PWM control on the negative side switch in the brake release state, it is possible to easily diagnose failures in the positive side switch 11 and the negative side switch 12, and also to reduce the size and heat generation of the mechanical brake device 2.

[0088] Although the present disclosure has been described in detail above, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0089] <Additional Notes> The following additional notes are provided regarding the above-described embodiment and modifications.

[0090] (Appendix 1) a positive-side switch 11 that, when turned on, closes a positive-side electric circuit 43P between a positive terminal 41P of the power source 10 and a positive terminal 42P of the non-excitation operation type mechanical brake device 2, and that, when turned off, opens the positive-side electric circuit 43P; a negative-side switch 12 that, when turned on, closes a negative-side electric circuit 43N between a negative terminal 41N of the power source 10 and a negative terminal 42N of the mechanical brake device 2, and that, when turned off, opens the negative-side electric circuit 43N; a switch control unit 13 that outputs an ON signal for turning on the positive-side switch 11 and an OFF signal for turning off the negative-side switch 12; Equipped with The switch control unit 13 When the mechanical brake device 2 is to operate the brake, an OFF signal is output to the positive side switch 11 and the negative side switch 12. When releasing the brake by the mechanical brake device 2, the brake driving device 1 outputs an on signal to the positive side switch 11 and the negative side switch 12 at the start of brake release, and thereafter, while maintaining the release of the brake by the mechanical brake device 2, alternately switches between outputting PWM-controlled on and off signals to the positive side switch 11 and outputting PWM-controlled on and off signals to the negative side switch 12 at predetermined time intervals. (Appendix 2) The brake driving device 1 described in Appendix 1, wherein the switch control unit 13 outputs an on signal to the negative side switch 12 while outputting a PWM-controlled on signal and an off signal to the positive side switch 11, and outputs an on signal to the positive side switch 11 while outputting a PWM-controlled on signal and an off signal to the negative side switch 12. (Appendix 3) a detection unit 14 that detects electrical information, which is at least one of a voltage applied to a brake coil 25 of the mechanical brake device 2 and a current flowing through the brake coil 25; a diagnosis unit 15 that diagnoses whether or not there is a fault in the positive-side switch 11 and the negative-side switch 12 based on electrical information detected by the detection unit 14 while the switch control unit 13 alternately switches between outputting PWM-controlled on and off signals to the positive-side switch 11 and outputting PWM-controlled on and off signals to the negative-side switch 12 at predetermined time intervals; The brake drive device 1 according to claim 2, comprising: (Appendix 4) The diagnosis unit 15 If the electrical information detected by the detection unit 14 is a substantially constant value equal to or greater than a predetermined first threshold value while the switch control unit 13 is outputting PWM-controlled on and off signals to the positive side switch 11, it is determined that the positive side switch 11 has a short-circuit fault, The brake driving device 1 described in Appendix 3, wherein if the electrical information detected by the detection unit 14 is an approximately constant value equal to or greater than a first threshold value while the switch control unit 13 is outputting PWM-controlled on signals and off signals to the negative side switch 12, it is determined that the negative side switch 12 has a short circuit fault. (Appendix 5) The brake driving device 1 described in Appendix 3, wherein the diagnostic unit 15 determines that at least one of the positive side switch 11 and the negative side switch 12 has an open circuit fault if the electrical information detected by the detection unit 14 is an approximately constant value that is equal to or less than a predetermined second threshold value both while the switch control unit 13 is outputting PWM-controlled on and off signals to the positive side switch 11 and while the switch control unit 13 is outputting PWM-controlled on and off signals to the negative side switch 12. (Appendix 6) The brake driving device 1 described in Appendix 3 includes an alarm output unit that outputs an alarm when the diagnostic unit 15 determines that at least one of the positive side switch 11 and the negative side switch 12 is faulty. (Appendix 7) a detection unit 14 that detects electrical information, which is at least one of a voltage applied to a brake coil 25 of the mechanical brake device 2 and a current flowing through the brake coil 25; a display unit 17 that displays electrical information detected by the detection unit 14 while the switch control unit 13 alternately switches between outputting PWM-controlled on and off signals to the positive-side switch 11 and outputting PWM-controlled on and off signals to the negative-side switch 12 at predetermined time intervals; and The brake drive device 1 according to claim 2, comprising: (Appendix 8) The mechanical brake device 2 applies a brake to the motor by using the elastic force of a spring 24 to press an armature 22 against a friction plate 21 to which a shaft 31 of the motor is connected, and releases the brake on the motor by pulling the armature 22 away from the friction plate 21 with an electromagnetic force generated by current flowing through a brake coil 25. The brake drive device 1 described in any one of Appendices 1 to 7. [Explanation of symbols]

[0091] 1 Brake drive unit 2 Mechanical braking device 10 Power supply 11 Positive switch 12 Negative switch 13 Switch control section 14 Detector 15 Diagnostic Department 16 Alarm output section 17 Display 18 Surge absorber 21 Friction plate 22 Amateur 23 End plate 24 springs 25 Brake coil 26 cores 27 Spacer 28 volts 31 Shaft 32 Hub 41P Positive terminal of power supply 41N Negative terminal of power supply 42P Positive terminal of mechanical brake device 42N Negative terminal of mechanical brake device 43P positive circuit 43N Negative-side circuit

Claims

1. a positive-side switch that, when turned on, closes a positive-side electric circuit between a positive terminal of a power supply and a positive terminal of a non-excitation operation type mechanical brake device, and that, when turned off, opens the positive-side electric circuit; a negative-side switch that, when turned on, closes a negative-side electric circuit between a negative terminal of the power source and a negative terminal of the mechanical brake device, and that, when turned off, opens the negative-side electric circuit; a switch control unit that outputs an ON signal for turning on the positive-side switch and an OFF signal for turning off the negative-side switch; Equipped with The switch control unit When the brake is to be applied by the mechanical brake device, an OFF signal is output to the positive side switch and the negative side switch, A brake drive device that, when releasing the brake by the mechanical brake device, outputs an on signal to the positive side switch and the negative side switch at the start of brake release, and thereafter, while the release of the brake by the mechanical brake device is maintained, alternately switches between outputting a PWM-controlled on signal and an off signal to the positive side switch and outputting a PWM-controlled on signal and an off signal to the negative side switch at predetermined time intervals.

2. 2. The brake drive device according to claim 1, wherein the switch control unit outputs an on signal to the negative side switch while outputting PWM-controlled on and off signals to the positive side switch, and outputs an on signal to the positive side switch while outputting PWM-controlled on and off signals to the negative side switch.

3. a detection unit that detects electrical information, which is at least one of a voltage applied to a brake coil of the mechanical brake device and a current flowing through the brake coil; a diagnosis unit that diagnoses whether or not there is a failure in the positive-side switch and the negative-side switch based on the electrical information detected by the detection unit while the switch control unit alternately switches between outputting PWM-controlled on-signals and off-signals to the positive-side switch and outputting PWM-controlled on-signals and off-signals to the negative-side switch at predetermined time intervals; The brake actuation device according to claim 2 , comprising:

4. The diagnostic unit if the electrical information detected by the detection unit is a substantially constant value equal to or greater than a predetermined first threshold value while the switch control unit is outputting PWM-controlled on and off signals to the positive-side switch, it is determined that the positive-side switch has a short-circuit fault; 4. The brake drive device according to claim 3, wherein if the electrical information detected by the detection unit is a substantially constant value equal to or greater than the first threshold value while the switch control unit is outputting PWM-controlled on and off signals to the negative switch, it is determined that the negative switch has a short-circuit fault.

5. 4. The brake drive device according to claim 3, wherein the diagnostic unit determines that at least one of the positive-side switch and the negative-side switch has an open-circuit fault when the electrical information detected by the detection unit is a substantially constant value equal to or less than a predetermined second threshold value both while the switch control unit is outputting PWM-controlled on-signals and off-signals to the positive-side switch and while the switch control unit is outputting PWM-controlled on-signals and off-signals to the negative-side switch.

6. The brake drive device according to claim 3 , further comprising an alarm output unit that outputs an alarm when the diagnosing unit determines that at least one of the positive-side switch and the negative-side switch has failed.

7. a detection unit that detects electrical information, which is at least one of a voltage applied to a brake coil of the mechanical brake device and a current flowing through the brake coil; a display unit that displays the electrical information detected by the detection unit while the switch control unit alternately switches between outputting PWM-controlled on and off signals to the positive-side switch and outputting PWM-controlled on and off signals to the negative-side switch at predetermined time intervals; and The brake actuation device according to claim 2 , comprising:

8. The brake drive device according to any one of claims 1 to 7, wherein the mechanical brake device applies a brake to the motor by using the elastic force of a spring to press an armature against a friction plate to which the motor shaft is connected, and releases the brake on the motor by pulling the armature away from the friction plate by electromagnetic force generated when a current flows through a brake coil.

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