Brake drive device for driving mechanical brake device

Abstract

A brake drive device is provided with: a positive-side switch for opening and closing a positive-side circuit between a power source and a mechanical brake device; a negative-side switch that opens and closes a negative-side circuit between the power source and the mechanical brake device; and a switch control unit that outputs an off signal to the positive-side switch and the negative-side switch when the brake is operated, outputs an on signal to the positive-side switch and the negative-side switch when the brake is released, and thereafter outputs an on signal to the positive-side switch and the negative-side switch when the brake is released, after the on signal is output to the positive-side switch and the negative-side switch during a period in which the brake release is maintained. The PWM-controlled ON / OFF signal is output to the positive-side switch, and the PWM-controlled ON / OFF signal is output to the negative-side switch at predetermined time intervals.

Description

Technical Field

[0001] The present disclosure relates to a brake drive device for driving a mechanical brake device. Background Art

[0002] In a motor drive device that drives a motor in a machine such as an industrial robot or a machine tool, a non-excitation operation type mechanical brake device is widely used to apply a brake to a rotating motor or fix a stopped motor so that it does not rotate. A switch is connected between the brake coil of the mechanical brake device and a power source. By performing an ON operation of the switch, current flows from the power source into the brake coil, and the brake of the mechanical brake device is released. Further, by performing an OFF operation of the switch, current does not flow from the power source into the brake coil, and thus, the mechanical brake device performs a braking operation.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-119530

[0006] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2011-195287

[0007] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2007-143311

[0008] Patent Document 4: Japanese Unexamined Patent Application Publication No. 08-182365 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] There is a need for a brake drive device that can easily diagnose a failure of a switch provided between a brake coil of a mechanical brake device and a power source, and can achieve miniaturization and low heat generation of the mechanical brake device.

[0011] Means for Solving the Problems

[0012] According to one aspect of the present disclosure, a brake drive device includes: a positive-side switch that closes a positive-side circuit between a positive terminal of a power supply and a positive terminal of a non-excited operation type mechanical brake device by performing a closing operation, and opens the positive-side circuit by performing an opening operation; a negative-side switch that closes a negative-side circuit between a negative terminal of the power supply and a negative terminal of the mechanical brake device by performing a closing operation, and opens the negative-side circuit by performing an opening operation; and a switch control unit that outputs a closing signal for performing a closing operation and an opening signal for performing an opening operation to the positive-side switch and the negative-side switch. The switch control unit performs the following operations: when causing the mechanical brake device to perform braking, outputs an opening signal to the positive-side switch and the negative-side switch; when releasing the braking of the mechanical brake device, outputs a closing signal to the positive-side switch and the negative-side switch at the start of braking release, and then, during the period of maintaining the release of the braking of the mechanical brake device, alternately switches every predetermined time to perform: outputting a PWM-controlled closing signal and an opening signal to the positive-side switch, and outputting a PWM-controlled closing signal and an opening signal to the negative-side switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 FIG. is a circuit diagram showing a brake drive device according to a first embodiment of the present disclosure.

[0014] Figure 2 FIG. is a cross-sectional view showing the structure of a mechanical brake device controlled by a brake drive device according to the first and second embodiments of the present disclosure, showing a state in which braking is applied to a motor.

[0015] Figure 3 FIG. is a cross-sectional view showing the structure of a mechanical brake device controlled by a brake drive device according to the first and second embodiments of the present disclosure, showing a state in which braking on the motor is released.

[0016] Figure 4 FIG. is a timing chart for explaining the operation and release of braking of a mechanical brake device in a brake drive device according to the first and second embodiments of the present disclosure.

[0017] Figure 5 FIG. is a timing chart showing waveforms of the positive-side switch and the negative-side switch of a brake drive device according to the first and second embodiments of the present disclosure when they are normal.

[0018] Figure 6 FIG. is a timing chart showing waveforms of the positive-side switch and the negative-side switch of a brake drive device according to the first and second embodiments of the present disclosure when a short-circuit fault occurs in the positive-side switch.

[0019] Figure 7 FIG. is a timing chart showing waveforms of the positive-side switch and the negative-side switch of a brake drive device according to the first and second embodiments of the present disclosure when an open-circuit fault occurs in the positive-side switch.

[0020] Figure 8 is a flowchart showing the operations related to fault diagnosis in the braking drive device according to the first embodiment of the present disclosure.

[0021] Figure 9 is a circuit diagram showing the braking drive device according to the second embodiment of the present disclosure.

[0022] Figure 10 is a flowchart showing the operations related to fault diagnosis in the braking drive device according to the second embodiment of the present disclosure. Detailed Embodiments

[0023] Hereinafter, the braking drive device of the mechanical braking device according to the driving embodiment will be described with reference to the drawings. In addition, in the following description, the same reference numerals are given to components having the same or similar functional structures. Also, repeated descriptions of these components may be omitted. Here, "turning on" of a switch means closing the circuit in which the switch is provided, that is, performing the turning-on operation of the switch, and the circuit in which the switch is provided is connected to form a closed state. In addition, "turning off" of a switch means opening the circuit in which the switch is provided, that is, performing the turning-off operation of the switch, and the circuit in which the switch is provided is cut off to form an open state.

[0024] <Structure of the Braking Drive Device According to the First Embodiment>

[0025] Figure 1 is a circuit diagram showing the braking drive device according to the first embodiment of the present disclosure.

[0026] The mechanical braking device 2 controlled by the braking drive device 1 according to the first embodiment of the present disclosure is a non-excitation operation type braking device that performs braking when not excited, that is, when no voltage is applied to the brake coil 25, and releases the braking when excited, that is, when voltage is applied to the brake coil 25.

[0027] Before describing the braking drive device 1 according to the first embodiment of the present disclosure, refer to Figure 2 and Figure 3 to describe the structure of the mechanical braking device 2 controlled by the braking drive device 1. Figure 2 is a cross-sectional view showing the structure of the mechanical braking device controlled by the braking drive device according to the first and second embodiments of the present disclosure, showing the state where braking is applied to the motor. Figure 3 is a cross-sectional view showing the structure of the mechanical braking device controlled by the braking drive device according to the first and second embodiments of the present disclosure, showing the state where the braking on the motor is released. Figure 2 and Figure 3The illustrated mechanical braking device 2 can be applied to the first and second embodiments.

[0028] As Figure 2 and Figure 3 shown, in the mechanical braking device 2, a friction plate 21 is disposed between the armature 22 and the end plate 23. The friction plate 21 is spline-bonded to the hub 32. The hub 32 and the shaft 31 of the motor are integrated, for example, by hot press fitting. Therefore, the friction plate 21 also rotates in linkage with the rotation of the shaft 31 of the motor. The end plate 23 and the spacer 27 are joined by bolts 28, and the armature 22 is joined to the spacer 27 so as to be movable in a direction approaching the friction plate 21 and a direction away from the friction plate 21. A spring 24 and a brake coil 25 are provided in the iron core 26. As Figure 2 shown, in the non-excitation state where no voltage is applied to the brake coil 25, the armature 22 is strongly pressed against the friction plate 21 by the elastic force of the spring 24, and the friction plate 21 is clamped between the armature 22 and the end plate 23 and cannot rotate. As a result, the shaft 31 of the motor joined to the friction plate 21 also cannot rotate, and a state where the motor is braked (braking operation state) is achieved. On the other hand, as Figure 3 shown, in the excitation state where a braking current flows through the brake coil 25, an electromagnetic force that can overcome the elastic force of the spring 24 pressing the armature 22 against the friction plate 21 is generated in the iron core 26. Thus, the armature 22 is attracted by the iron core 26, and the friction plate 21 is released from the contact with the armature 22 and the end plate 23. As a result, the friction plate 21 and further the shaft 31 of the motor can rotate freely, and a state where the braking of the motor is released (braking release state) is achieved.

[0029] The mechanical braking device 2 is controlled by a brake drive device 1. As Figure 1 shown, the brake drive device 1 of 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 Figure 1 it, regarding the mechanical braking device 2, only the brake coil 25 is illustrated.

[0030] The power supply 10 outputs a DC voltage. The power supply 10 is constituted by, for example, a rectifier that converts an AC voltage into a DC voltage, a switching regulator, or a battery. As an example, the power supply 10 outputs a DC voltage with a voltage value of 24V, but it may also be a power supply that outputs a DC voltage with other voltage values (for example, 15V, 12V, 5V, etc.).

[0031] The positive-side switch 11 and the negative-side switch 12 are respectively connected in series with the brake coil 25 of the mechanical braking device 2. In Figure 1In the example shown, a positive-side switch 11 is provided to open (cut off) or close (connect) the positive-side circuit 43P between the positive terminal 41P of the power supply 10 and the positive terminal 42P of the mechanical braking device 2. In addition, a negative-side switch 12 is provided to open (cut off) or close (connect) the negative-side circuit 43N between the negative terminal 41N of the power supply 10 and the negative terminal 42N of the mechanical braking device 2. Further, in Figure 1 In the example shown, one positive-side switch 11 and one negative-side switch 12 are provided respectively. However, as a modification, two or more of each may be provided. Examples of the positive-side switch 11 and the negative-side switch 12 include FET, IGBT, thyristor, GTO, transistor, relay, etc. The types of the positive-side switch 11 and the negative-side switch 12 themselves do not limit this embodiment, and switch elements other than the examples may also be used.

[0032] The on-operation and off-operation of the positive-side switch 11 and the negative-side switch 12 are controlled by a switch control unit 13.

[0033] That is, in order to control the positive-side switch 11 and the negative-side switch 12 to perform on-operations, the switch control unit 13 sends on-signals to the positive-side switch 11 and the negative-side switch 12. When the positive-side switch 11 receives the on-signal from the switch control unit 13, it performs an on-operation to close the positive-side circuit 43P between the power supply 10 and the brake coil 25. In addition, when the negative-side switch 12 receives the on-signal from the switch control unit 13, it performs an on-operation to close the negative-side circuit 43N between the power supply 10 and the brake coil 25. However, when an open-circuit fault occurs in the positive-side switch 11 or the negative-side switch 12, the switch does not perform an on-operation even if it receives the on-signal from the switch control unit 13.

[0034] In addition, in order to control the positive-side switch 11 and the negative-side switch 12 to perform off-operations, the switch control unit 13 sends off-signals to the positive-side switch 11 and the negative-side switch 12. When the positive-side switch 11 receives the off-signal from the switch control unit 13, it performs an off-operation to open the positive-side circuit 43P between the power supply 10 and the brake coil 25. In addition, when the negative-side switch 12 receives the off-signal from the switch control unit 13, it performs an off-operation to open the negative-side circuit 43N between the power supply 10 and the brake coil 25. However, when a short-circuit fault occurs in the positive-side switch 11 or the negative-side switch 12, the switch does not perform an off-operation even if it receives the off-signal from the switch control unit 13.

[0035] Here, with reference to Figure 4 the operation and release of the braking of the mechanical braking device 2 will be described. Figure 4This is a timing chart for explaining the operation and release of the brake of the mechanical brake device in the first and second embodiments of the present disclosure. Figure 4 The description related to the timing chart shown can be applied to the first and second embodiments. Figure 4 The upper part shows the on / off state of the positive-side switch 11 or the negative-side switch 12. Figure 4 The lower part shows the average voltage applied to the brake coil 25.

[0036] When the switch control unit 13 causes the mechanical brake device 2 to perform a braking operation (for example, from the start to time t 1 ), it outputs a disconnection signal to the positive-side switch 11 and the negative-side switch 12. The positive-side switch 11 and the negative-side switch 12 that receive the disconnection signal from the switch control unit 13 perform a disconnection operation, opening the positive-side circuit 43P and the negative-side circuit 43N between the power supply 10 and the brake coil 25. As a result, the current flowing from the power supply 10 toward the brake coil 25 is cut off. Therefore, the average voltage of the brake coil 25 becomes 0 (zero), and the electromagnetic force generated in the iron core 26 disappears. The elastic force of the spring 24 overcomes the electromagnetic force generated in the iron core 26, whereby the armature 22 is strongly pressed against the friction plate 21, and the braking operation (braking operation state) of the mechanical brake device 2 is achieved.

[0037] In addition, when the switch control unit 13 releases the brake of the mechanical brake device 2, it performs the following series of controls. The switch control unit 13 first outputs an on signal to the positive-side switch 11 and the negative-side switch 12 at time t 1 at the start of brake release. The positive-side switch 11 and the negative-side switch 12 that receive the on signal from the switch control unit 13 close the positive-side circuit 43P and the negative-side circuit 43N. As a result, current flows from the power supply 10 to the brake coil 25, and the average voltage of the brake coil 25 is V 1 , and an electromagnetic force is generated in the iron core 26 that can overcome the elastic force of the spring 24 that presses the armature 22 against the friction plate 21. By this electromagnetic force, the armature 22 is attracted by the iron 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 further the shaft 31 of the motor can rotate freely, and the state of releasing the brake on the motor (brake release state) is achieved.

[0038] After the brake of the mechanical brake device 2 is temporarily released, an electromagnetic force that is somewhat smaller than the electromagnetic force generated in the iron core 26 at the start of brake release can overcome the elastic force of the spring 24. Therefore, at time t 2, in order to maintain this brake release state, the switch control unit 13 alternately switches every predetermined time to: output a turn-on signal and a turn-off signal controlled by PWM (Pulse Width Modulation) to the positive-side switch 11, and output a turn-on signal and a turn-off signal controlled by PWM to the negative-side switch 12. In Figure 4 In the upper part of [], as an example, the on-off state of one switch of the positive-side switch 11 or the negative-side switch 12 is shown. During the period when the switch control unit 13 outputs a turn-on signal and a turn-off signal controlled by PWM to the positive-side switch 11, the switch control unit 13 outputs a turn-on signal to the negative-side switch 12. In addition, during the period when the switch control unit 13 outputs a turn-on signal and a turn-off signal controlled by PWM to the negative-side switch 12, the switch control unit 13 outputs a turn-on signal to the positive-side switch 11. In this way, at the moment t when the on-off operations of the positive-side switch 11 and the negative-side switch 12 are PWM-controlled 2 After that, current also flows from the power supply 10 to the brake coil 25, but its magnitude is smaller than that at the moment t 1 to the moment t 2 . Therefore, the average voltage of the brake coil 25 is V 2 (<V 1 ), and the heat generation of the mechanical brake device 2 is reduced. In addition, even if the mechanical brake device 2 is miniaturized, no problem will occur. The duty ratio for PWM control is set to a magnitude such that an electromagnetic force capable of overcoming the elastic force of the spring 24 is generated. By setting the duty ratio in this way, the state of releasing the friction plate 21 from contact with the armature 22 and the end plate 23 can be maintained, and thus the brake release state can be maintained. As an example of the duty ratio for PWM control, for example, 50% can be set, but the value cited here is only an example, and other values can also be used.

[0039] During the period when the switch control unit 13 switches the PWM control of the positive-side switch 11 and the PWM control of the negative-side switch 12, the diagnostic unit 15 performs fault diagnosis on the positive-side switch 11 and the negative-side switch 12, which will be described in detail later. Therefore, in order to implement the SBC (Safe Brake Control) function according to IEC / EN61800-5-2, for example, the following switching can be performed every about 500 milliseconds: the switching by the switch control unit 13 of outputting a turn-on signal and a turn-off signal controlled by PWM to the positive-side switch 11 and outputting a turn-on signal and a turn-off signal controlled by PWM to the negative-side switch 12. The value cited here is only an example, and other values can also be used.

[0040] Return Figure 1To explain, the surge absorber 18 is connected between the positive terminal and the negative terminal of the brake coil 25 in a manner of being connected in parallel with the mechanical brake device 2. The surge absorber 18 removes instantaneous high voltages such as switching surges or noises of the switches 11 and 12.

[0041] 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 transmitted to the diagnosis unit 15. In addition, hereinafter, the voltage applied to the brake coil 25 is sometimes referred to as "brake coil voltage", and the current flowing through the brake coil 25 is sometimes referred to as "brake coil current".

[0042] The diagnosis unit 15 diagnoses whether there is a failure in the positive-side switch 11 and the negative-side switch 12 based on the following electrical information: during the period when the switch control unit 13 alternately switches to output a PWM-controlled ON signal and OFF signal to the positive-side switch 11 and a PWM-controlled ON signal and OFF signal to the negative-side switch 12 at regular intervals, the electrical information detected by the detection unit 14.

[0043] When it is determined by the diagnosis unit 15 that at least one of the positive-side switch 11 and the negative-side switch 12 has failed, the alarm output unit 16 outputs an alarm.

[0044] Based on the alarm output of the alarm output unit 16, the diagnosis result of the diagnosis unit 15 can be displayed on, for example, a display device (not shown). Examples of the display device include a single display device, the brake drive device 1, or a display device attached to a motor drive device having the brake drive device 1, and a display device attached to a personal computer and a portable terminal, etc. For example, the display device displays, for example, "positive-side switch normal", "negative-side switch normal", "positive-side switch failure", or "negative-side switch failure". The above display examples of the display device are just one example, and "positive-side switch normal", "negative-side switch normal", "positive-side switch failure", or "negative-side switch failure" can also be displayed according to other expressions or depictions. In addition, in the case where a failure occurs in the positive-side switch or the negative-side switch, as more detailed failure content, it can be displayed whether it is a short-circuit failure or an open-circuit failure.

[0045] Based on the alarm output of the alarm output unit 16, the diagnostic result of the diagnostic unit 15 can be output through a sounding audio device (not shown) such as sound, a speaker, a buzzer, a bell, etc. For example, the timbre, scale, rhythm, or melody can be set in a way that can distinguish the differences among "positive-side switch normal", "negative-side switch normal", "positive-side switch failure", and "negative-side switch failure". In addition, the audio device can be set to be silent when both the positive-side switch and the negative-side switch are normal, and only make a sound when the positive-side switch fails or the negative-side switch fails. Furthermore, when a failure occurs in the positive-side switch or the negative-side switch, as more detailed failure content, the audio device can make a sound that can identify whether it is a short-circuit failure or an open-circuit failure.

[0046] It is possible to adopt a method of printing the diagnostic result of the diagnostic unit 15 on paper or the like using a printer for display.

[0047] As described above, examples of notifying the operator of the diagnostic result of the diagnostic unit 15 have been described, but they can also be implemented by appropriately combining them. In addition, each time the diagnostic result of the diagnostic unit 15 is obtained, it can be stored and accumulated in a memory, and databaseization can be performed to assist in failure prediction or preventive maintenance.

[0048] The operator 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 diagnostic result of the diagnostic unit 15. Therefore, when the operator can confirm that a failure has occurred in the positive-side switch 11 or the negative-side switch 12 based on the diagnostic result of the diagnostic unit 15, countermeasures such as replacing or repairing the positive-side switch 11 or the negative-side switch 12 can be taken.

[0049] At least one processor serving as an arithmetic processing device is provided in the brake drive device 1 or in a motor drive device having the brake drive device 1. As the arithmetic processing device, for example, there are ICs, LSIs, CPUs, MPUs, DSPs, etc. The arithmetic processing device has a switch control unit 13, a detection unit 14, a diagnosis unit 15, an alarm output unit 16, and other processing circuits. These units included in the arithmetic processing device are, for example, functional modules realized by programs executed on the processor. For example, in the case where the switch control unit 13, the detection unit 14, the diagnosis unit 15, the alarm output unit 16, and other processing circuits are constructed in the form of programs, by causing the arithmetic processing device to operate according to the programs, the functions of the respective units can be realized. Programs for executing the respective processes of the switch control unit 13, the detection unit 14, the diagnosis unit 15, the alarm output unit 16, and other processing circuits can be provided in the form of being 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 can be implemented as a semiconductor integrated circuit in which programs for realizing the functions of the respective units are written.

[0050] In addition, at least one memory serving as a storage device is provided in the brake drive device 1 or in a motor drive device having the brake drive device 1. As the memory, for example, there are non-volatile memories such as EEPROM (registered trademark) that can be electrically erased / recorded, or random access memories such as DRAM and SRAM that can perform high-speed reading and writing. In addition, the storage device can also have a structure such as an HDD or an SSD. 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 can also be stored in the memory. In addition, electrical information acquired by the detection unit 14 is stored in the memory. In addition, the diagnosis results of the diagnosis unit 15 are stored in the memory. In addition, various data related to the brake drive device 1 or a motor drive device having the brake drive device 1 are stored in the memory.

[0051] <Operation of the Brake Drive Device of the First Embodiment>

[0052] Refer to Figures 5 - 7 The operation of the brake drive device of the first embodiment will be described with reference to the illustrated timing chart. Figures 5 - 7 The explanations related to the illustrated timing chart can be applied to the first and second embodiments. In Figures 5 - 7 it, from the upper row to the lower row, the on-signal and off-signal applied to the positive-side switch 11, the on-signal and 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 are shown in sequence. In addition, in Figures 5 - 7Among them, as an example, from the start to time t 11 Execute the braking operation process. At time t 11 Start the brake release process. At time t 11 Maintain the brake release state thereafter.

[0053] Figure 5 It is a timing chart of each waveform when the positive-side switch and the negative-side switch of the brake drive device according to the first and second embodiments of the present disclosure are normal.

[0054] When the positive-side switch 11 and the negative-side switch 12 are normal, according to the on-signal and off-signal output from the switch control unit 13, the positive-side switch 11 and the negative-side switch 12 perform on-actions and off-actions.

[0055] When the switch control unit 13 operates the brake of the mechanical brake device 2 (for example, from the start to time t 11 ), it outputs an off-signal to the positive-side switch 11 and the negative-side switch 12. The positive-side switch 11 and the negative-side switch 12 that receive the off-signal from the switch control unit 13 perform off-actions, opening the positive-side circuit 43P and the negative-side circuit 43N between the power supply 10 and the brake coil 25. As a result, the current flowing from the power supply 10 to the brake coil 25 is cut off. Therefore, the voltage and current of the brake coil 25 are 0 (zero). No electromagnetic force is generated in the brake coil 25. Therefore, the armature 22 is strongly pressed against the friction plate 21 by the elastic force of the spring 24, and the brake of the mechanical brake device 2 operates.

[0056] At time t 11 Start the brake release process. The switch control unit 13 outputs an on-signal to the positive-side switch 11 and the negative-side switch 12 at time t 11 The positive-side switch 11 and the negative-side switch 12 that receive the on-signal from the switch control unit 13 close the positive-side circuit 43P and the negative-side circuit 43N. As a result, the voltage of the brake coil 25 is V 1 , and the current (the maximum value is I 1 ) flows from the power supply 10 to the brake coil 25, and an electromagnetic force that can overcome the elastic force of the spring 24 pressing the armature 22 against the friction plate 21 is generated in the iron core 26. By this electromagnetic force, the armature 22 is attracted by the iron core 26, and the friction plate 21 is released from the contact with the armature 22 and the end plate 23. As a result, the friction plate 21 and further the shaft 31 of the motor can rotate freely, and the state of braking the motor is released.

[0057] At time t 12Thereafter, in order to maintain the brake release state, the switch control unit 13 alternately switches every predetermined time T to perform: outputting a turned-on signal and a turned-off signal that are PWM-controlled to the positive-side switch 11, and outputting a turned-on signal and a turned-off signal that are PWM-controlled to the negative-side switch 12. As the predetermined time T for performing PWM control, for example, about 500 milliseconds is set, but the value cited here is only an example, and other values may also be used. Regarding the predetermined time T, it can be stored in a rewritable storage unit (not shown) so that it can be rewritten by an external device. Thus, even after the predetermined time T is temporarily set, it can be changed to an appropriate value as needed.

[0058] For example, if the predetermined time T for performing PWM control on the switch with a high failure probability among the positive-side switch 11 and the negative-side switch 12 is set to a longer time, the failure of the switch with a high failure probability can be monitored more closely. Another example is that if the predetermined time T for performing PWM control on one of the positive-side switch 11 and the negative-side switch 12 with excellent heat dissipation is set to a longer time, the heat generation caused by the switching operation of the one switch with excellent heat dissipation can be suppressed.

[0059] To maintain the brake release state, during the period from time t 12 to time t 13 , during the period from time t 14 to time t 15 , and during the period from time t 16 to time t 17 , the switch control unit 13 outputs a turned-on signal and a turned-off signal that are PWM-controlled to the positive-side switch 11, and outputs a turned-on signal to the negative-side switch 12. The positive-side switch 11 that receives the turned-on signal and the turned-off signal that are PWM-controlled by the switch control unit 13 performs a turning-on and turning-off operation, closing and opening the positive-side circuit 43P between the power supply 10 and the brake coil 25. In addition, the negative-side switch 12 that receives the turned-on signal from the switch control unit 13 closes the negative-side circuit 43N. As a result, the voltage of the brake coil 25 vibrates and varies up and down between V 1 and 0 (zero). In addition, a vibration current smaller than the maximum value I 1 of the brake coil current flows from the power supply 10 to the brake coil 25. The duty ratio for PWM control is set to such a magnitude as to generate an electromagnetic force that can overcome the elastic force of the spring 24. Therefore, the brake release state in which the friction plate 21 is released from contact with the armature 22 and the end plate 23 can be maintained.

[0060] To maintain the brake release state, during the period from time t 13 to time t 14 , during the period from time t 15 to time t 16 , and at time t17 Thereafter, the switch control unit 13 outputs an on signal to the positive-side switch 11, and outputs a PWM-controlled on signal and an off signal to the negative-side switch 12. The positive-side switch 11 that receives the on signal from the switch control unit 13 closes the positive-side circuit 43P. In addition, the negative-side switch 12 that receives the PWM-controlled on signal and off signal from the switch control unit 13 performs an on / off operation to close and open the negative-side circuit 43N between the power supply 10 and the brake coil 25. As a result, the voltage of the brake coil 25 vibrates and varies up and down between V 1 and 0 (zero). In addition, a vibration current smaller than the maximum value I of the brake coil current flows from the power supply 10 to the brake coil 25. The duty ratio for PWM control is set to such a magnitude as to generate an electromagnetic force capable of overcoming the elastic force of the spring 24. Therefore, the brake release state in which the friction plate 21 is released from contact with the armature 22 and the end plate 23 can be maintained. 1 In this way, at the moment t when the brake release state is maintained

[0061] thereafter, the switch control unit 13 alternately switches every predetermined time T to perform: outputting a PWM-controlled on signal and an off signal to the positive-side switch 11, and outputting a PWM-controlled on signal and an off signal to the negative-side switch 12. When the positive-side switch 11 and the negative-side switch 12 are normal, according to the PWM-controlled on signals and off signals alternately applied to the positive-side switch 11 and the negative-side switch 12, the positive-side switch 11 and the negative-side switch 12 perform on / off operations. Therefore, the voltage and current of the brake coil 25 change vibrationally. 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. At the moment t when the switch control unit 13 alternately switches the PWM control for controlling the on / off of the positive-side switch 11 and the PWM control for controlling the on / off of the negative-side switch 12 every predetermined time 12 thereafter, when the electrical information detected by the detection unit 14 always changes vibrationally, the diagnosis unit 15 determines that both the positive-side switch 11 and the negative-side switch 12 are normal. 12

[0062] Figure 6 is a timing chart of each waveform when a short-circuit fault occurs in the positive-side switch of the brake drive device according to the first and second embodiments of the present disclosure.

[0063] For example, when a short-circuit fault occurs in the positive-side switch 11 and the negative-side switch 12 is normal, the positive-side switch 11 remains in the on state regardless of the on signal and off signal output from the switch control unit 13. On the other hand, the normal negative-side switch 12 performs an on / off operation according to the on signal and off signal output from the switch control unit 13.

[0064] When the switch control unit 13 activates the braking operation of the mechanical braking device 2 (e.g., from the start to time t 11 ), it outputs a disconnection signal to the positive-side switch 11 and the negative-side switch 12. Even if the positive-side switch 11 with a short-circuit fault receives the disconnection signal from the switch control unit 13, it does not perform a disconnection operation and maintains the state where the positive-side circuit 43P between the power supply 10 and the brake coil 25 is closed. On the other hand, the negative-side switch 12 that receives the disconnection signal from the switch control unit 13 performs a disconnection operation to open the negative-side circuit 43N between the power supply 10 and the brake coil 25. Since the negative-side 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 thus the voltage and current of the brake coil 25 are 0 (zero). No electromagnetic force is generated in the brake coil 25. Therefore, the armature 22 is strongly pressed against the friction plate 21 by the elastic force of the spring 24, and the braking operation of the mechanical braking device 2 is performed.

[0065] At time t 11 , the brake release process starts. The switch control unit 13 outputs an ON signal to the positive-side switch 11 and the negative-side switch 12 at time t 11 . The positive-side switch 11 and the negative-side switch 12 that receive the ON signal from the switch control unit 13 close the positive-side circuit 43P and the negative-side circuit 43N. As a result, the voltage of the brake coil 25 is V 1 , and the current (with a maximum value of I 1 ) flows from the power supply 10 to the brake coil 25, and the iron core 26 generates an electromagnetic force that can overcome the elastic force of the spring 24 pressing the armature 22 against the friction plate 21. Due to this electromagnetic force, the armature 22 is attracted by the iron 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 further the shaft 31 of the motor can rotate freely, and the state of braking the motor is released.

[0066] At time t 12 and later, in order to maintain this brake release state, the switch control unit 13 alternately switches every predetermined time T to perform: outputting a PWM-controlled ON signal and a disconnection signal to the positive-side switch 11, and outputting a PWM-controlled ON signal and a disconnection signal to the negative-side switch 12.

[0067] That is, during the period from time t 12 to time t 13 , during the period from time t 14 to time t 15 , and during the period from time t 16 to time t 17During this period, the switch control unit 13 outputs a PWM-controlled on-signal and off-signal to the positive-side switch 11, and outputs an on-signal to the negative-side switch 12. The positive-side switch 11 that has received the PWM-controlled on-signal and off-signal from the switch control unit 13 has a short-circuit fault. Therefore, the positive-side circuit 43P between the power supply 10 and the brake coil 25 remains in a closed state. In addition, the negative-side switch 12 that has received the on-signal from the switch control unit 13 closes the negative-side circuit 43N. Therefore, during this period, the positive-side switch 11 and the negative-side switch 12 are both in a closed state as they were from time t 11 to time t 12 . The voltage of the brake coil 25 is V 1 , and a current (maximum value is I 1 ) flows from the power supply 10 to the brake coil 25, resulting in a waveform F 1 . As described with reference to Figure 5 , if the positive-side switch 11 is normal, then according to the PWM-controlled on-signal and off-signal, the voltage of the brake coil 25 vibrates up and down between V 1 and 0 (zero), and a vibration current smaller than the maximum value I 1 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 a short-circuit fault, a fixed voltage V 1 is applied to the brake coil 25, and a fixed current I 1 flows through the brake coil 25, resulting in a waveform F 1 . However, an electromagnetic force that can overcome the elastic force of the spring 24 is generated, so the brake release state in which the friction plate 21 is released from contact with the armature 22 and the end plate 23 can be maintained.

[0068] During the period from time t 13 to time t 14 , during the period from time t 15 to time t 16 , and after time t 17 , the switch control unit 13 outputs an on-signal to the positive-side switch 11, and outputs a PWM-controlled on-signal and off-signal to the negative-side switch 12. The positive-side switch 11 that has received the on-signal from the switch control unit 13 closes the positive-side circuit 43P. In addition, the negative-side switch 12 that has received the PWM-controlled on-signal and off-signal from the switch control unit 13 performs an on-off operation to close and open the negative-side circuit 43N between the power supply 10 and the brake coil 25. As a result, the voltage of the brake coil 25 vibrates up and down between V 1 and 0 (zero), and a current smaller than the maximum value I 1 of the brake coil current flows from the power supply 10 to the brake coil 25.A small vibration current. The duty ratio for PWM control is set to such a magnitude as to generate an electromagnetic force that can overcome the elastic force of the spring 24, so that the braking release state in which the friction plate 21 is released from contact with the armature 22 and the end plate 23 can be maintained.

[0069] Thus, in the case where a short-circuit fault occurs in the positive-side switch 11, at every prescribed time T, the timing t at which the on-signal and off-signal that are PWM-controlled are alternately switched and output to the positive-side switch 11, and the on-signal and off-signal that are PWM-controlled are output to the negative-side switch 12 12 After that, a fixed voltage V is applied to the brake coil 25 1 , and a fixed current I flows through the brake coil 25 1 Such a waveform F 1 . Therefore, during the period in which the on-signal and off-signal that are PWM-controlled are output to the positive-side switch 11 (from the time t 12 to the time t 13 period, from the time t 14 to the time t 15 period, and from the time t 16 to the time t 17 period), when the electrical information detected by the detection unit 14 is a substantially fixed value equal to or higher than a predetermined first threshold value, it is determined that a short-circuit fault has occurred in the positive-side switch 11. Here, the first threshold value is set to a value that is lower than the maximum voltage value that the brake coil voltage can take by a certain degree (for example, a value that is about 10 to 20% lower) when the electrical information is voltage, and is set to a value that is lower than the maximum current value that the brake coil current can take by a certain degree (for example, a value that is about 10 to 20% lower) when the electrical information is current. The numerical examples shown here are merely examples, and other values may also be used. In addition, regarding the first threshold value, it can be stored in a rewritable storage unit (not shown) so that it can be rewritten by an external device. Thus, even after the first threshold value is temporarily set, it can be changed to an appropriate value as needed.

[0070] As described above, in Figure 6 , the case where a short-circuit fault occurs in the positive-side switch 11 has been described as an example. Regarding the description of the short-circuit fault of the negative-side switch 12, the structure in which the positive-side switch 11 and the negative-side switch 12 are swapped is applied in the description of Figure 6 . That is, during the period in which PWM control for turning on and off the negative-side switch 12 is performed (from the time t 13 to the time t 14 period, from the time t 15 to the time t 16 period, and the time t 17Thereafter, when the electrical information detected by the detection unit 14 is a substantially fixed value equal to or greater than a preset first threshold value, it is determined that a short-circuit fault has occurred in the negative-side switch 12.

[0071] Figure 7 It is a timing chart of each waveform when an open-circuit fault occurs in the positive-side switch of the brake drive device according to the first and second embodiments of the present disclosure.

[0072] For example, when an open-circuit fault occurs in the positive-side switch 11 and the negative-side switch 12 is normal, regardless of the ON signal and OFF signal output from the switch control unit 13, the positive-side switch 11 remains in the open state. On the other hand, the normal negative-side switch 12 performs ON / OFF operations according to the ON signal and OFF signal output from the switch control unit 13.

[0073] When the switch control unit 13 operates the brake of the mechanical brake device 2 (for example, from the start to time t 11 ), it outputs an OFF signal to the positive-side switch 11 and the negative-side switch 12. Since an open-circuit fault occurs in the positive-side switch 11, the positive-side circuit 43P between the power supply 10 and the brake coil 25 remains in an open state. On the other hand, the negative-side switch 12 that receives the OFF signal from the switch control unit 13 performs an OFF operation to open the negative-side circuit 43N between the power supply 10 and the brake coil 25. Since the negative-side 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, so the voltage and current of the brake coil 25 are 0 (zero). Since no electromagnetic force is generated in the brake coil 25, the armature 22 is strongly pressed against the friction plate 21 by the elastic force of the spring 24, and the brake of the mechanical brake device 2 operates.

[0074] At time t 11 The brake release process is started. The switch control unit 13 outputs an ON signal to the positive-side switch 11 and the negative-side switch 12 at time t 11 The negative-side switch 12 that receives the ON signal from the switch control unit 13 closes the negative-side circuit 43N between the power supply 10 and the brake coil 25. However, since an open-circuit fault occurs in the positive-side switch 11, the positive-side switch 11 does not perform an ON operation, and the positive-side circuit 43P between the power supply 10 and the brake coil 25 remains in an open state. Therefore, the current flowing from the power supply 10 to the brake coil 25 is cut off, so the voltage and current of the brake coil 25 are 0 (zero). Since no electromagnetic force is generated in the brake coil 25, the armature 22 is strongly pressed against the friction plate 21 by the elastic force of the spring 24, and the brake of the mechanical brake device 2 remains in the braking state.

[0075] At time t 12After that, the switch control unit 13 alternately switches every predetermined time T to: output a PWM-controlled ON signal and OFF signal to the positive-side switch 11, and output a PWM-controlled ON signal and OFF signal to the negative-side switch 12.

[0076] That is, during the period from time t 12 to time t 13 , during the period from time t 14 to time t 15 , and during the period from time t 16 to time t 17 , the switch control unit 13 outputs a PWM-controlled ON signal and OFF signal to the positive-side switch 11, and outputs an ON signal to the negative-side switch 12. The positive-side switch 11 that has received the PWM-controlled ON signal and OFF signal from the switch control unit 13 has an open-circuit fault, so it does not perform the ON operation, and the positive-side circuit 43P between the power supply 10 and the brake coil 25 remains in an open state. In addition, the negative-side switch 12 that has received the ON signal from the switch control unit 13 closes the negative-side 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 the OFF state, and a waveform F in which both the voltage and current of the brake coil 25 are 0 appears 2 .

[0077] During the period from time t 13 to time t 14 , during the period from time t 15 to time t 16 , and after time t 17 , the switch control unit 13 outputs an ON signal to the positive-side switch 11, and outputs a PWM-controlled ON signal and OFF signal to the negative-side switch 12. The negative-side switch 12 that has received the PWM-controlled ON signal and OFF signal from the switch control unit 13 performs an ON / OFF operation to close and open the negative-side circuit 43N between the power supply 10 and the brake coil 25. However, the positive-side switch 11 has an open-circuit fault, so the positive-side circuit 43P between the power supply 10 and the brake coil 25 remains in an open state. Therefore, during this period, the positive-side switch 11 and the negative-side switch 12 become the OFF state, and a waveform F in which both the voltage and current of the brake coil 25 are 0 appears 2 .

[0078] As described with reference to Figure 5 , if the positive-side switch 11 is normal, then according to the PWM-controlled ON signal and OFF signal, the voltage of the brake coil 25 vibrates up and down between V 1 and 0 (zero), and a current greater than the maximum value I of the brake coil current should flow from the power supply 10 to the brake coil 25 1A small vibration current. However, the positive-side switch 11 has an open-circuit fault, so the waveform F where both the voltage and current of the braking coil 25 are always 0 appears. 2 . Therefore, during the period when the switch control unit 13 outputs a PWM-controlled on-signal and off-signal to the positive-side switch 11 (from time t 12 to time t 13 , from time t 14 to time t 15 , and from time t 16 to time t 17 ), and during the period when the switch control unit 13 outputs a PWM-controlled on-signal and off-signal to the negative-side switch 12 (from time t 13 to time t 14 , from time t 15 to time t 16 , and after time t17), when the electrical information detected by the detection unit 14 is a substantially fixed value below a preset 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. Here, the second threshold is set to a positive value near 0 volts when the electrical information is voltage, and to a positive value near 0 amperes when the electrical information is current. The numerical examples shown here are just examples, and other values are also possible. In addition, regarding the second threshold, it can also be stored in a rewritable storage unit (not shown) so that it can be rewritten by an external device. Thus, even after the second threshold is temporarily set, it can be changed to an appropriate value as needed.

[0079] As above, in Figure 7 , the case where the positive-side switch 11 has an open-circuit fault has been described as an example. Regarding the open-circuit fault of the negative-side switch 12, the structure in which the positive-side switch 11 and the negative-side switch 12 are swapped is applied to the description related to Figure 7 .

[0080] When the negative-side switch 12 has an open-circuit fault, as Figure 7 shown, the waveform F where both the voltage and current of the braking coil 25 are always 0 also always appears. 2 . That is, in the case where the positive-side switch 11 has an open-circuit fault and the case where the negative-side switch 12 has an open-circuit fault, the waveform F where both the voltage and current of the braking coil 25 are 0 appears. 2 . Therefore, it is impossible to determine based on the waveform F where both the voltage and current of the braking coil 25 are 0. 2To distinguish whether an open circuit fault has occurred in the positive-side switch 11, or in the negative-side switch 12, or in both the positive-side switch 11 and the negative-side switch 12. When the electrical information detected by the detection unit 14 is a substantially fixed value below a preset second threshold, the diagnosis unit 15 determines that an open circuit fault has occurred in at least one of the positive-side switch 11 and the negative-side switch 12.

[0081] Figure 8 It is a flowchart showing the 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 set as the voltage applied to the brake coil 25. When the electrical information detected by the detection unit 14 is the current flowing through the brake coil 25, Figure 8 The shown flowchart is applied by replacing "the voltage applied to the brake coil 25" with "the current flowing through the brake coil 25".

[0082] In step S101, the switch control unit 13 and the diagnosis unit 15 determine whether the mechanical brake device 2 is in the brake release state. If it is determined that the mechanical brake device 2 is in the braking operation state, the process returns to step S101. When it is determined that the mechanical brake device 2 is in the 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.

[0083] In step S102, the switch control unit 13 alternately switches every predetermined time to: output a PWM-controlled ON signal and OFF signal to the positive-side switch 11, and output a PWM-controlled ON signal and OFF signal to the negative-side switch 12. While the switch control unit 13 outputs a PWM-controlled ON signal and OFF signal to the positive-side switch 11, it outputs an ON signal to the negative-side switch 12. In addition, while the switch control unit 13 outputs a PWM-controlled ON signal and OFF signal to the negative-side switch 12, it outputs an ON signal to the positive-side switch 11.

[0084] In step S103, the detection unit 14 detects the brake coil voltage. The information related to the detected brake coil voltage is transmitted to the diagnosis unit 15.

[0085] In step S104, the diagnosis unit 15 determines whether the voltage of the brake coil 25 is a substantially fixed value above the first threshold.

[0086] When it is determined in step S104 that the voltage applied to the brake coil 25 is a substantially fixed value equal to or higher than the first threshold, the process proceeds to S106. In step S106, when it is determined in step S104 that the brake coil voltage detected by the detection unit 14 is a substantially fixed value equal to or higher than the first threshold during the period in which the positive-side switch 11 is output with a PWM-controlled ON signal and OFF signal, the diagnosis unit 15 determines that a short-circuit fault has occurred in the positive-side switch 11. Further, in step S106, when it is determined in step S104 that the brake coil voltage detected by the detection unit 14 is a substantially fixed value equal to or higher than the first threshold during the period in which the negative-side switch 12 is output with a PWM-controlled ON signal and OFF signal, the diagnosis unit 15 determines that a short-circuit fault has occurred in the negative-side switch 12. After step S106, the process returns to step S101.

[0087] When it is determined in step S104 that the voltage applied to the brake coil 25 is not a substantially fixed value equal to or higher than the first threshold, the process proceeds to S105. In step S105, the diagnosis unit 15 determines whether the voltage of the brake coil 25 is a substantially fixed value equal to or lower than the second threshold.

[0088] When it is determined in step S105 that the voltage of the brake coil 25 is a substantially fixed value equal to or lower than the second threshold, the process proceeds to step S108. In step S108, the diagnosis unit 15 determines that an open-circuit 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.

[0089] When it is determined in step S105 that the voltage of the brake coil 25 is not a substantially fixed value equal to or lower 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.

[0090] In addition, the processes of step S104 and step S105 may be executed in a swapped order.

[0091] According to the first embodiment of the present disclosure, during the PWM control of the positive-side switch 11 and the PWM control of the negative-side switch in the brake release state, the diagnosis unit 15 can easily diagnose faults in the positive-side switch 11 and the negative-side switch 12. Further, by performing the PWM control of the positive-side switch 11 and the PWM control of the negative-side switch in the brake release state, it is possible to maintain the brake release state with less power than at the start of brake release, and thus, it is possible to achieve miniaturization and low heat generation of the mechanical brake device 2.

[0092] <Structure of Brake Driving Device of Second Embodiment>

[0093] Figure 9This is a circuit diagram showing the brake drive device according to the second embodiment of the present disclosure.

[0094] In the first embodiment described with reference to Figures 1 - 8 diagnostic processing is performed by the diagnostic unit 15 based on the electrical information detected by the detection unit 14. In the second embodiment, instead of Figure 1 the diagnostic unit 15 and the alarm output unit 16, a display unit 17 that displays the electrical information detected by the detection unit 14 is provided.

[0095] As Figure 9 shown, the brake drive 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 Figure 9 for the mechanical brake device 2 controlled by the brake drive device 1, only the brake coil 25 is shown.

[0096] For the mechanical brake device 2, the power supply 10, the positive-side switch 11, the negative-side switch 12, the switch control unit 13, the detection unit 14, the diagnostic unit 15, and the surge absorber 18, as described with reference to Figures 1 - 9 in the first embodiment.

[0097] The display unit 17 displays the following electrical information: during the period when the switch control unit 13 alternately switches to output a PWM-controlled ON signal and OFF signal to the positive-side switch 11 and a PWM-controlled ON signal and OFF signal to the negative-side switch 12 at regular intervals, the electrical information detected by the detection unit 14. As an example of the display unit 17, there are a single display device, a display device of the brake drive device 1 or attached to a motor drive device having the brake drive device 1, and a display device attached to a personal computer and a portable terminal, etc.

[0098] <Operation of the Brake Drive Device of the Second Embodiment>

[0099] In the second embodiment, the description related to the timing diagram shown in Figures 5 - 7 can also be applied.

[0100] Figure 10 This is a flowchart showing the operation related to fault diagnosis in the brake drive device according to the second embodiment of the present disclosure. Here, as an example, the electrical information detected by the detection unit 14 is set as the voltage applied to the brake coil 25. When the electrical information detected by the detection unit 14 is the current flowing through the brake coil 25, Figure 10 the flowchart shown in

[0101] In step S201, the switch control unit 13 and the diagnosis unit 15 determine whether the mechanical braking device 2 is in the brake release state. If it is determined that the mechanical braking device 2 is in the braking operation state, the process returns to step S201. When it is determined that the mechanical braking device 2 is in the 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 enters step S102.

[0102] In step S202, the switch control unit 13 alternately switches every predetermined time to perform: outputting a PWM-controlled on signal and off signal to the positive side switch 11, and outputting a PWM-controlled on signal and off signal to the negative side switch 12. During the period when the switch control unit 13 outputs a PWM-controlled on signal and off signal to the positive side switch 11, the switch control unit 13 outputs an on signal to the negative side switch 12. In addition, during the period when the switch control unit 13 outputs a PWM-controlled on signal and off signal to the negative side switch 12, the switch control unit 13 outputs an on signal to the positive side switch 11.

[0103] In step S203, the detection unit 14 detects the brake coil voltage. Information related to the detected brake coil voltage is transmitted to the display unit 17.

[0104] In step S203, the display unit 17 displays the brake coil voltage.

[0105] In the display unit 17, for example, as Figures 4 - 6 shown in the example, the following brake coil voltage is displayed: during the period when the switch control unit 13 alternately switches every predetermined time to output a PWM-controlled on signal and off signal to the positive side switch 11 and a PWM-controlled on signal and off signal to the negative side switch 12, the brake coil voltage detected by the detection unit 14. By visually confirming the display content of the display unit 17, the operator can determine whether the positive side switch 11 and the negative side switch 12 are normal, whether a short circuit fault occurs in the positive side switch 11, whether a short circuit fault occurs in the negative side switch, and whether an open circuit fault occurs in at least one of the positive side switch 11 and the negative side switch.

[0106] According to the second embodiment of the present disclosure, the operator can easily diagnose faults in the positive side switch 11 and the negative side switch 12 based on the display content of the display unit 17 for electrical information related to the brake coil 25 of the mechanical braking device 2 during the period of PWM control of the positive side switch 11 and PWM control of the negative side switch in the brake release state. In addition, 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 can be maintained with less power than at the start of brake release. Therefore, miniaturization and low heat generation of the mechanical braking device 2 can be achieved.

[0107] <Balancing Fault Diagnosis and Miniaturization and Low Heat Generation of a Mechanical Brake Device>

[0108] 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 faults in the positive-side switch 11 and the negative-side switch 12, and it is possible to achieve miniaturization and low heat generation of the mechanical brake device 2.

[0109] As described above, the present disclosure has been described in detail, but the present disclosure is not limited to the above-described respective embodiments. These embodiments can be subjected to various additions, replacements, changes, partial deletions, etc. within the scope of not departing from the spirit of the present disclosure, or within the scope of not departing from the spirit of the present disclosure derived from the content described in the claims and its equivalents. In addition, 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 an example, but are not limited thereto. In addition, the same applies to the case where numerical values or mathematical formulas are used in the description of the above-described embodiments.

[0110] <Supplementary Note>

[0111] Regarding the above-described embodiments and modification examples, the following supplementary note is further disclosed.

[0112] (Supplementary Note 1)

[0113] A brake drive device 1 includes:

[0114] A positive-side switch 11 that closes the positive-side circuit 43P between the positive terminal 41P of the power supply 10 and the positive terminal 42P of the non-excitation operation type mechanical brake device 2 by performing a closing operation, and opens the positive-side circuit 43P by performing an opening operation;

[0115] A negative-side switch 12 that closes the negative-side circuit 43N between the negative terminal 41N of the power supply 10 and the negative terminal 42N of the mechanical brake device 2 by performing a closing operation, and opens the negative-side circuit 43N by performing an opening operation; and

[0116] A switch control unit 13 that outputs a closing signal for performing a closing operation and an opening signal for performing an opening operation to the positive-side switch 11 and the negative-side switch 12,

[0117] The switch control unit 13 performs the following operations:

[0118] When making the mechanical brake device 2 perform a braking operation, outputs an opening signal to the positive-side switch 11 and the negative-side switch 12;

[0119] When releasing the brake of the mechanical brake device 2, an ON signal is output to the positive-side switch 11 and the negative-side switch 12 at the start of brake release. After that, during the period of maintaining the release of the brake of the mechanical brake device 2, switching is alternately performed at regular intervals as follows: an ON signal and an OFF signal controlled by PWM are output to the positive-side switch 11, and an ON signal and an OFF signal controlled by PWM are output to the negative-side switch 12.

[0120] (Supplementary Note 2)

[0121] According to the brake drive device 1 described in Supplementary Note 1, wherein,

[0122] During the period when the switch control unit 13 outputs an ON signal and an OFF signal controlled by PWM to the positive-side switch 11, an ON signal is output to the negative-side switch 12. During the period when the switch control unit 13 outputs an ON signal and an OFF signal controlled by PWM to the negative-side switch 12, an ON signal is output to the positive-side switch 11.

[0123] (Supplementary Note 3)

[0124] According to the brake drive device 1 described in Supplementary Note 2, wherein,

[0125] The brake drive device 1 has:

[0126] A detection unit 14 that 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; and

[0127] A diagnosis unit 15 that diagnoses whether there is a failure in the positive-side switch 11 and the negative-side switch 12 based on the following electrical information: the electrical information detected by the detection unit 14 during the period when the switch control unit 13 alternately switches at regular intervals to output an ON signal and an OFF signal controlled by PWM to the positive-side switch 11 and an ON signal and an OFF signal controlled by PWM to the negative-side switch 12.

[0128] (Supplementary Note 4)

[0129] According to the brake drive device 1 described in Supplementary Note 3, wherein,

[0130] The diagnosis unit 15 performs the following operations:

[0131] When the electrical information detected by the detection unit 14 during the period when the switch control unit 13 outputs an ON signal and an OFF signal controlled by PWM to the positive-side switch 11 is a substantially fixed value equal to or greater than a predetermined first threshold, it is determined that a short-circuit failure has occurred in the positive-side switch 11.

[0132] When the electrical information detected by the detection unit 14 is a substantially fixed value equal to or greater than the first threshold during the period in which the switch control unit 13 outputs a PWM-controlled on-signal and off-signal to the negative-side switch 12, it is determined that a short-circuit fault has occurred in the negative-side switch 12.

[0133] (Appendix 5)

[0134] According to the braking drive device 1 described in Appendix 3, wherein,

[0135] During the period in which the switch control unit 13 outputs a PWM-controlled on-signal and off-signal to the positive-side switch 11 and during the period in which the switch control unit 13 outputs a PWM-controlled on-signal and off-signal to the negative-side switch 12, when the electrical information detected by the detection unit 14 is a substantially fixed value equal to or less than a preset second threshold, the diagnosis unit 15 determines that an open-circuit fault has occurred in at least one of the positive-side switch 11 and the negative-side switch 12.

[0136] (Appendix 6)

[0137] According to the braking drive device 1 described in Appendix 3, wherein,

[0138] The braking drive device 1 includes: an alarm output unit that outputs an alarm when the diagnosis unit 15 determines that a fault has occurred in at least one of the positive-side switch 11 and the negative-side switch 12.

[0139] (Appendix 7)

[0140] According to the braking drive device 1 described in Appendix 2, wherein,

[0141] The braking drive device 1 includes:

[0142] A detection unit 14 that detects electrical information, which is at least one of the voltage applied to the brake coil 25 of the mechanical braking device 2 and the current flowing through the brake coil 25; and

[0143] A display unit 17 that displays the following electrical information: the electrical information detected by the detection unit 14 during the period in which the switch control unit 13 alternately switches at regular intervals between outputting a PWM-controlled on-signal and off-signal to the positive-side switch 11 and outputting a PWM-controlled on-signal and off-signal to the negative-side switch 12.

[0144] (Appendix 8)

[0145] According to the braking drive device 1 described in any one of Appendices 1 to 7, wherein,

[0146] The mechanical brake device 2 presses the armature 22 against the friction plate 21 coupled to the shaft 31 of the motor by the elastic force of the spring 24, thereby applying a brake to the motor, and separates the armature 22 from the friction plate 21 by the electromagnetic force generated when current flows through the brake coil 25, thereby releasing the brake on the motor.

[0147] Symbol Explanation

[0148] 1 Brake drive device

[0149] 2 Mechanical brake device

[0150] 10 Power supply

[0151] 11 Positive side switch

[0152] 12 Negative side switch

[0153] 13 Switch control unit

[0154] 14 Detection unit

[0155] 15 Diagnosis unit

[0156] 16 Alarm output unit

[0157] 17 Display unit

[0158] 18 Surge absorber

[0159] 21 Friction plate

[0160] 22 Armature

[0161] 23 End plate

[0162] 24 Spring

[0163] 25 Brake coil

[0164] 26 Iron core

[0165] 27 Spacer

[0166] 28 Bolt

[0167] 31 Shaft

[0168] 32 Hub

[0169] 41P Positive terminal of the power supply

[0170] 41N Negative terminal of the power supply

[0171] 42P Positive terminal of the mechanical brake device

[0172] 42N Negative terminal of the mechanical brake device

[0173] 43P Positive side circuit

[0174] 43N negative side circuit.

Claims

1. A braking drive device, characterized in that, the braking drive device has: a positive-side switch, which closes the positive-side circuit between the positive terminal of the power supply and the positive terminal of the non-excitation-operated mechanical braking device by performing a closing operation, and opens the positive-side circuit by performing an opening operation; a negative-side switch, which closes the negative-side circuit between the negative terminal of the power supply and the negative terminal of the mechanical braking device by performing a closing operation, and opens the negative-side circuit by performing an opening operation; and a switch control unit, which outputs a closing signal for performing a closing operation and an opening signal for performing an opening operation to the positive-side switch and the negative-side switch, the switch control unit performs the following operations: when braking the mechanical braking device, outputs an opening signal to the positive-side switch and the negative-side switch; when releasing the brake of the mechanical braking device, outputs a closing signal to the positive-side switch and the negative-side switch at the start of brake release, and then, during the period of maintaining the release of the brake of the mechanical braking device, alternately switches every predetermined time to perform: outputting a PWM-controlled closing signal and an opening signal to the positive-side switch, and outputting a PWM-controlled closing signal and an opening signal to the negative-side switch.

2. The braking drive device according to claim 1, characterized in that, the switch control unit outputs a closing signal to the negative-side switch during the period of outputting a PWM-controlled closing signal and an opening signal to the positive-side switch, and outputs a closing signal to the positive-side switch during the period of outputting a PWM-controlled closing signal and an opening signal to the negative-side switch.

3. The braking drive device according to claim 2, characterized in that, the braking drive device has: a detection unit, which detects electrical information, the electrical information being at least one of the voltage applied to the brake coil of the mechanical braking device and the current flowing through the brake coil; and a diagnosis unit, which diagnoses whether there is a fault in the positive-side switch and the negative-side switch based on the following electrical information: the electrical information detected by the detection unit during the period when the switch control unit alternately switches every predetermined time to output a PWM-controlled closing signal and an opening signal to the positive-side switch and a PWM-controlled closing signal and an opening signal to the negative-side switch.

4. The braking drive device according to claim 3, characterized in that, the diagnosis unit performs the following operations: when the electrical information detected by the detection unit during the period when the switch control unit outputs a PWM-controlled closing signal and an opening signal to the positive-side switch is a substantially fixed value equal to or greater than a predetermined first threshold, it is determined that a short-circuit fault has occurred in the positive-side switch; when the electrical information detected by the detection unit during the period when the switch control unit outputs a PWM-controlled closing signal and an opening signal to the negative-side switch is a substantially fixed value equal to or greater than the first threshold, it is determined that a short-circuit fault has occurred in the negative-side switch.

5. The braking drive device according to claim 3, wherein, during the period when the switch control unit outputs a PWM-controlled on-signal and off-signal to the positive-side switch, and during the period when the switch control unit outputs a PWM-controlled on-signal and off-signal to the negative-side switch, when the electrical information detected by the detection unit is a substantially fixed value below a preset second threshold, the diagnosis unit determines that an open-circuit fault has occurred in at least one of the positive-side switch and the negative-side switch.

6. The braking drive device according to claim 3, wherein, the braking drive device includes: an alarm output unit that outputs an alarm when the diagnosis unit determines that a fault has occurred in at least one of the positive-side switch and the negative-side switch.

7. The braking drive device according to claim 2, wherein, the braking drive device includes: a detection unit that detects electrical information, which is at least one of the voltage applied to the brake coil of the mechanical braking device and the current flowing through the brake coil; and a display unit that displays the following electrical information: the electrical information detected by the detection unit during the period when the switch control unit alternately switches every predetermined time to output a PWM-controlled on-signal and off-signal to the positive-side switch and a PWM-controlled on-signal and off-signal to the negative-side switch.

8. The braking drive device according to any one of claims 1 to 7, wherein, the mechanical braking device presses the armature against the friction plate coupled to the shaft of the motor by the elastic force of a spring, thereby applying braking to the motor, and separates the armature from the friction plate by the electromagnetic force generated when current flows through the brake coil, thereby releasing the braking on the motor.

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