Brake drive device for driving a mechanical brake device

Abstract

This brake drive device comprises: a positive-side switch for opening / closing a positive-side electrical path between a power source and a mechanical braking device; a negative-side switch for opening / closing a negative-side electrical path between the power source and the mechanical braking 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 brake release start when braking is to be released, and thereafter while keeping braking released, alternately switching between outputting a PWM-controlled ON / OFF signal to the positive-side switch and outputting 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 drive device that drives a mechanical brake device. GENERAL STATE OF THE ART

[0002] In a motor drive device that drives a motor in a machine such as an industrial robot and a machine tool, a non-energized actuation type mechanical brake device is often used to apply a brake to the rotating motor and to fix the stopped motor so that the motor is prevented from rotating. A switch is connected between a brake coil of the mechanical brake device and a power supply. A current flows from the power supply to the brake coil by performing an ON movement of the switch, and braking by the mechanical brake device is released. Further, a current is prevented from flowing from the power supply to the brake coil by performing an OFF movement of the switch, and thus braking of the mechanical brake device is applied. [LIST OF CITATIONS][PATENT LITERATURE] [PTL 1] JP 2019-119530A [PTL 2] JP 2011-195287A [PTL 3] JP 2007-143311A [PTL 4] JP H08-182365A SUMMARY OF THE INVENTION [TECHNICAL PROBLEM]

[0003] A braking device that can easily diagnose a malfunction in a switch provided between a brake coil of a mechanical braking device and a power supply, and also can reduce the size and heat generation of the mechanical braking device, is desired. [SOLVING THE PROBLEM]

[0004] According to one aspect of the present disclosure, a brake drive device includes: a positive switch configured to close a positive circuit between a positive terminal of a power supply and a positive terminal of a non-energized actuation type mechanical brake device by performing an ON movement, and to open the positive circuit by performing an OFF movement; a negative switch configured to close a negative circuit between a negative terminal of the power supply and a negative terminal of the mechanical brake device by performing the ON movement and to open the negative circuit by performing the OFF movement; and a switch control unit configured to output an ON signal to the positive switch and the negative switch to cause the ON movement to be performed and an OFF signal.to cause the OFF movement to be performed, wherein the switch control unit, when a brake is applied by the mechanical braking device, outputs the OFF signal to the positive switch and the negative switch, and when braking is released by the mechanical braking device, outputs the ON signal to the positive switch and the negative switch at a time of brake release initiation, and then switches and performs PWM control for the positive switch for each predetermined period of time between an output of the ON signal and the OFF signal subjected to PWM control for the positive switch and an output of the ON signal and the OFF signal subjected to PWM control for the negative switch, while maintaining a release of the brake by the mechanical braking device. SHORT DESCRIPTION OF DRAWINGS Fig. 1 is a circuit diagram illustrating a brake drive device according to a first embodiment of the present disclosure. Fig. 2 is a cross-sectional view illustrating a structure of a mechanical brake device controlled by the brake drive device according to the first embodiment and a second embodiment of the present disclosure, and illustrates a state in which a brake for a motor is applied. Fig. 3 is a cross-sectional view illustrating a structure of the mechanical braking device controlled by the brake driving device according to the first and second embodiments of the present disclosure, and illustrating a state in which braking is released for the motor. Fig. 4 is a timing chart illustrating application and release of a brake of the mechanical brake device in the brake drive device according to the first and second embodiments of the present disclosure. Fig. 5 is a timing chart illustrating each waveform when a positive switch and a negative switch of the brake drive device according to the first and second embodiments of the present disclosure are normal. Fig. 6 is a timing chart illustrating each waveform when the positive switch and the brake drive device according to the first and second embodiments of the present disclosure experience a short circuit failure. Fig. 7 is a timing chart illustrating each waveform when the positive switch of the brake drive device according to the first and second embodiments of the present disclosure experiences an open circuit failure. Fig. 8 is a flowchart illustrating a movement related to a fault diagnosis in the brake drive device according to the first embodiment of the present disclosure. Fig. 9 is a circuit diagram illustrating the brake driving device according to the second embodiment of the present disclosure. Fig. 10 is a flowchart illustrating a movement related to a fault diagnosis in the brake drive device according to the second embodiment of the present disclosure. DESCRIPTION OF EMBODIMENTS

[0005] Hereinafter, a brake driving device that drives a mechanical brake device according to the embodiments will be described with reference to drawings. It is understood that a configuration having the same or similar function will be designated by the same reference numeral in the following description. Then, redundant description of the configuration can be omitted. Herein, "ON" of a switch means the closing of an electric circuit provided with the switch, that is, when a switch performs an ON movement, an electric circuit provided with the switch is connected and brought into a closed state.Furthermore, "OFF" of a switch means the opening of an electrical circuit provided with the switch, that is, when a switch performs an OFF movement, an electrical circuit provided with the switch is disconnected and brought into an open state. <Konfiguration der Bremsantriebsvorrichtung gemäß der ersten Ausführungsform>

[0006] Fig. 1 is a circuit diagram illustrating a brake drive device according to a first embodiment of the present disclosure.

[0007] A mechanical brake device 2 controlled by a brake drive device 1 according to the first embodiment of the present disclosure is a non-energization actuation type brake device that applies a brake during non-energization without applying a voltage to a brake coil 25 and releases braking during energization with application of a voltage to the brake coil 25.

[0008] Before describing the brake drive device 1 according to the first embodiment of the present disclosure, a structure of the mechanical brake device 2 controlled by the brake drive device 1 will be described with reference to FIG. Fig. 2 and Fig. 3 described. Fig. 2 is a cross-sectional view illustrating a structure of a mechanical brake device controlled by the brake drive device according to the first embodiment and a second embodiment of the present disclosure, and illustrates a state in which a brake for a motor is applied. Fig. 3 is a cross-sectional view illustrating a structure of the mechanical brake device controlled by the brake drive device according to the first and second embodiments of the present disclosure. The mechanical brake device 2 shown in FIGS. Fig. 2 and Fig. 3 is applicable to the first and second embodiments.

[0009] As in the Fig. 2 and Fig. 3, in the mechanical brake device 2, a friction plate 21 is arranged between an armature 22 and an end plate 23. A hub 32 is spline-coupled to the friction plate 21. The hub 32 and a shaft 31 of a motor are integrated, for example, by shrink fitting, and therefore the friction plate 21 also rotates in conjunction with the rotation of the shaft 31 of the motor. The end plate 23 and a spacer 27 are coupled by a bolt 28, and the armature 22 is coupled to the spacer 27 such that the armature 22 can move in a direction closer to and a direction away from the friction plate 21. A spring 24 and the brake coil 25 are provided in a core 26. As shown in Fig. 2, in a non-excitation state in which no voltage is applied to the brake coil 25, the armature 22 is strongly pressed against the friction plate 21 by a spring 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 shaft 31 of the motor coupled to the friction plate 21 cannot rotate, resulting in a state in which braking for the motor (brake applied state) is applied. On the other hand, as shown in Fig. 3, in an energization state in which a braking current flows through the brake coil 25, an electromagnetic force that overcomes the spring force of the spring 24 pressing the armature 22 against the friction plate 21 is generated in the core 26, and the armature 22 is therefore brought closer 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 hence the shaft 31 of the motor can rotate freely, resulting in a state in which braking is released for the motor (brake release state).

[0010] The mechanical braking device 2 is controlled by the brake drive device 1. As in Fig. 1, the brake drive device 1 according to the first embodiment of the present disclosure includes a power supply 10, a positive switch 11, a negative 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. Fig. 1 illustrates only the brake coil 25 for the mechanical braking device 2.

[0011] The power supply 10 outputs a DC voltage. The power supply 10 is formed, for example, from a rectifier that converts an AC voltage to a DC voltage, a switching regulator, a battery, or the like. As an example, the power supply 10 outputs a DC voltage having a voltage value of 24 V, but may be a power supply that outputs a DC voltage having a different voltage value (e.g., 15 V, 12 V, 5 V, and the like).

[0012] The positive switch 11 and the negative switch 12 are each connected in series with the brake coil 25 of the mechanical braking device 2. In the Fig. 1, the positive switch 11 is provided, which opens (disconnects) or closes (connects) a positive circuit 43P between a positive terminal 41P of the power supply 10 and a positive terminal 42P of the mechanical braking device 2. Further, the negative switch 12 is provided, which opens (disconnects) or closes (connects) a negative circuit 43N between a negative terminal 41N of the power supply 10 and a negative terminal 42N of the mechanical braking device 2. Note that in the example shown in Fig. 1, one positive switch 11 and one negative switch 12 are provided, but two or more positive switches 11 and two or more negative switches 12 may be provided as a modification example. As an example of the positive switch 11 and the negative switch 12, there are an FET, an IGBT, a thyristor, a GTO, a transistor, a relay, and the like. A type of the positive switch 11 and the negative switch 12 itself does not limit the present embodiment, and a switching element other than the exemplary switch may be used.

[0013] The ON movement and OFF movement of the positive switch 11 and the negative switch 12 are controlled by the switch control unit 13.

[0014] In other words, the switch control unit 13 transmits an ON signal to the positive switch 11 and the negative switch 12 to perform control to cause the positive switch 11 and the negative switch 12 to perform the ON movement. When the positive switch 11 receives the ON signal from the switch control unit 13, the positive switch 11 performs the ON movement and closes the positive circuit 43P between the power supply 10 and the brake coil 25. When the negative switch 12 receives the ON signal from the switch control unit 13, the negative switch 12 performs the ON movement and closes the negative circuit 43N between the power supply 10 and the brake coil 25.However, in a case that the positive switch 11 or the negative switch 12 experiences an open circuit failure, the switch does not perform the ON movement even if the switch receives the ON signal from the switch control unit 13.

[0015] Further, the switch control unit 13 transmits an OFF signal to the positive switch 11 and the negative switch 12 to perform control to cause the positive switch 11 and the negative switch 12 to perform the OFF movement. When the positive switch 11 receives the OFF signal from the switch control unit 13, the positive switch 11 performs the OFF movement and opens the positive circuit 43P between the power supply 10 and the brake coil 25. When the negative switch 12 receives the OFF signal from the switch control unit 13, the negative switch 12 performs the OFF movement and opens the negative circuit 43N between the power supply 10 and the brake coil 25. However, in a case that the positive switch 11 or the negative switch 12 experiences a short-circuit failure, the switch does not perform the OFF movement even if the switch receives the OFF signal from the switch control unit 13.

[0016] Herein, the actuation and release of the mechanical braking device 2 are described with reference to Fig. 4 described. Fig. 4 is a timing chart illustrating the actuation and release of braking of the mechanical brake device in the brake drive device according to the first and second embodiments of the present disclosure. The description including the timing chart shown in Fig. 4 applies to the first and second embodiments. An upper row in Fig. 4 illustrates an ON and OFF state of the positive switch 11 or the negative switch 12, and a lower row in Fig. 4 illustrates an average voltage applied to the brake coil 25.

[0017] When braking is applied by the mechanical brake device 2 (for example, from the start at a time t1), the switch control unit 13 outputs the OFF signal to the positive switch 11 and the negative switch 12. The positive switch 11 and the negative switch 12, which have received the OFF signal from the switch control unit 13, perform the OFF movement and open the positive circuit 43P and the negative circuit 43N between the power supply 10 and the brake coil 25. In this way, a current from the power supply 10 to the brake coil 25 is interrupted, and therefore, an average voltage of the brake coil 25 is 0 (zero), and no electromagnetic force is generated in the core 26.A spring force of the spring 24 overcomes an electromagnetic force generated in the core 26, and therefore the armature 22 is strongly pressed against the friction plate 21, and braking by the mechanical brake device 2 is applied (brake application state).

[0018] When braking is released by the mechanical brake device 2, the switch control unit 13 performs a series of the following control aspects. First, the switch control unit 13 outputs the ON signal to the positive switch 11 and the negative switch 12 at a time t1, which is an ON time of brake release start. The positive switch 11 and the negative switch 12, having received the ON signal from the switch control unit 13, close the positive circuit 43P and the negative circuit 43N. In this way, a current flows from the power supply 10 to the brake coil 25, an average voltage of the brake coil 25 is V1, and an electromagnetic force that overcomes a spring force of the spring 24 to press the armature 22 against the friction plate 21 is generated in the core 26.The armature 22 is brought closer to the core 26 by the electromagnetic force, and the friction plate 21 is released from contacts with the armature 22 and the end plate 23. As a result, the friction plate 21 and therefore the shaft 31 of the motor can rotate freely, resulting in a state in which braking is released for the motor (brake release state).

[0019] Once the braking of the mechanical brake device 2 is released, even an electromagnetic force that is somewhat smaller than an electromagnetic force generated by the core 26 at the time of brake release initiation can overcome a spring force of the spring 24. At a time t2, the switch control unit 13 alternately switches and performs, for maintaining the brake release state, between outputting the ON signal and the OFF signal under pulse width modulation (PWM) control for the positive switch 11 and outputting the ON signal and the OFF signal subjected to PWM control for the negative switch 12 for each predetermined period. In the upper row in Fig. 4 illustrates the ON and OFF states of a switch of the positive switch 11 and the negative switch 12 as an example. The switch control unit 13 outputs an ON signal to the negative switch 12, while the switch control unit 13 outputs the ON signal and the OFF signal subjected to PWM control for the positive switch 11. Further, the switch control unit 13 outputs the ON signal to the positive switch 11, while the switch control unit 13 outputs the ON signal and the OFF signal subjected to PWM control for the positive switch 12.In this way, at and after time t2, at which the ON and OFF movements of the positive switch 11 and the negative switch 12 are subjected to PWM control, a current also flows from the power supply 10 to the brake coil 25, but the magnitude of the current is smaller than the magnitude of the current from time t1 to time t2, and therefore, an average voltage of the brake coil 25 is V2 (<V1), and the heat generation of the mechanical brake device 2 is reduced. Furthermore, no problem arises even if the size of the mechanical brake device 2 is reduced. A duty ratio used in PWM control is set in advance to a size to an extent that an electromagnetic force that overcomes a spring force of the spring 24 is generated.By setting the duty ratio in this way, the state in which the friction plate 21 is released from contact with the armature 22 and the end plate 23 can be maintained, and therefore the brake release state can be maintained. As an example of the duty ratio used in PWM control, for example, 50% can be set, but one numerical value herein is merely an example, and other numerical values may be adjusted.

[0020] Details are described below, and failure diagnosis of the positive switch 11 and the negative switch 12 is performed by the diagnosis unit 15, while the switch control unit 13 switches between PWM control for the positive switch 11 and PWM control for the negative switch 12. Therefore, to achieve a safety brake control (SBC) function that functions in accordance with IEC / EN61800-5-2, switching by the switch control unit 13 between outputting the ON signal and the OFF signal subjected to PWM control for the positive switch 11 and outputting the ON signal and the OFF signal subjected to PWM control for the negative switch 12 may be performed for, for example, about 500 milliseconds. The numerical value herein is merely an example, and other numerical values may be set.

[0021] The description returns to Fig. 1, and the surge absorber 18 is connected between the positive terminal and the negative terminal of the brake coil 25 in parallel with the mechanical braking device 2. The surge absorber 18 removes a short-term high voltage, such as an opening / closing surge and noise of the switches 11 and 12.

[0022] The detection unit 14 detects electrical information including at least one of a voltage applied to the brake coil 25 of the mechanical brake device 2 and a current flowing through the brake coil 25. The electrical information detected by the detection unit 14 is transmitted to the diagnosis unit 15. Note that hereinafter, a voltage applied to the brake coil 25 may be referred to as a "brake coil voltage," and a current flowing through the brake coil 25 may be referred to as a "brake coil current."

[0023] The diagnosis unit 15 makes a diagnosis of the presence or failure in the positive switch 11 and the negative switch 12 based on the electricity information detected by the detection unit 14, while the switch control unit 13 alternately switches and performs, for every predetermined period of time, an output of the ON signal and the OFF signal subjected to PWM control for the positive switch 11 and an output of the ON signal and the OFF signal subjected to PWM control for the negative switch 12.

[0024] The alarm output unit 16 outputs an alarm when the diagnostic unit 15 determines that at least one of the positive switch 11 and the negative switch 12 is faulty.

[0025] A diagnosis result by the diagnosis unit 15 can be displayed, for example, on a display device (not illustrated) based on an output of an alarm from the alarm output unit 16. As an example of the display device, there are a single display device, a display device attached to the brake drive device 1 or a motor drive device including the brake drive device 1, a display device attached to a personal computer and a portable terminal, and the like. The display device performs, for example, display of "positive switch normal," "negative switch normal," "positive switch abnormal," or "negative switch abnormal."The above-described display example by the display device is merely an example. "Positive switch normal," "negative switch normal," "positive switch faulty," or "negative switch faulty" may be displayed based on different expressions and illustrations. Note that when the positive switch or negative switch is faulty, whether the switch is experiencing a short-circuit failure or an open-circuit failure may be displayed as a more detailed fault content.

[0026] A diagnosis result by the diagnosis unit 15 may be output from an acoustic device (not illustrated) that outputs a sound such as a voice, a loudspeaker announcement, a buzzer, or a gong based on an alarm output from the alarm output unit 16. For example, in order to be able to distinguish a difference between "positive switch normal," "negative switch normal," "positive switch malfunction," and "negative switch malfunction," a timbre, a scale, a rhythm, a melody, or the like may be set. Further, the acoustic device may remain silent when "positive switch and negative switch are normal," and may output a sound only when "positive switch malfunction" or "negative switch malfunction."It should be noted that if the positive switch or the negative switch is faulty, the audible device can emit a tone that identifies whether the switch is experiencing a short circuit failure or an open circuit failure.

[0027] A diagnosis result by the diagnosis unit 15 can be printed and displayed on paper and the like using a printer.

[0028] The examples of notification of a diagnostic result by the diagnostic unit 15 to an operator are described above and can be conveniently combined and achieved. Furthermore, each time a diagnostic result is acquired by the diagnostic unit 15, the diagnostic result can be stored, collected, and stored in a database, and thus used to support failure prediction and preventive maintenance.

[0029] An operator can quickly and reliably detect a state of the positive switch 11 and the negative switch 12 of the brake drive device 1 based on a diagnosis result notified by the diagnosis unit 15. Therefore, if the operator can confirm from the diagnosis result by the diagnosis unit 15 that the positive switch 11 or the negative switch 12 is malfunctioning, the operator can take action such as replacing or repairing the positive switch 11 or the negative switch 12.

[0030] At least one processor, which is an arithmetic processing device, is provided in the brake drive device 1 or the motor drive device including the brake drive device 1. As the arithmetic processing device, there are, for example, an IC, an LSI, a CPU, an MPU, a DSP, and the like. The arithmetic processing device includes the switch control unit 13, the detection unit 14, the diagnosis unit 15, the alarm output unit 16, and other processing circuits. Each of these units included in the arithmetic processing device is, for example, a functional module achieved by a program executed on a processor.For example, when the switch control unit 13, the detection unit 14, the diagnostic unit 15, the alarm output unit 16, and other processing circuits are formed in a program form, the arithmetic processing device performs a movement according to the program, and therefore, a function of each unit can be achieved. The program for executing each processing part of the switch control unit 13, the detection unit 14, the diagnostic unit 15, the alarm output unit 16, and other processing circuits may be provided in the form of recording in a computer-readable recording medium such as a solid-state 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 the other processing circuit may be achieved as a semiconductor integrated circuit in which the program that fulfills the function of each unit is written.

[0031] At least one memory, which is a storage device, is provided in the brake drive device 1 or the motor drive device including the brake drive device 1. As the memory, there is a non-volatile memory that is electrically erasable and writable, such as an EEPROM (registered trademark), a random access memory that can perform reading and writing at a high speed, such as a DRAM and an SRAM, or the like. Further, the storage device may have a configuration such as an HDD and an SSD. The program for causing the switch control unit 13, the detection unit 14, the diagnosis unit 15, the alarm output unit 16, and other processing circuits to perform a movement may be stored in the memory. Electricity information acquired by the detection unit 14 is stored in the memory.A diagnosis result by the diagnostic unit 15 is stored in the memory. Various data regarding the brake drive device 1 or the motor drive device including the brake drive device 1 are stored in the memory. <Bewegung der Bremsantriebsvorrichtung gemäß der ersten Ausführungsform>

[0032] A movement of the brake drive device according to the first embodiment will be described with reference to timing charts shown in the Fig. 5 to 7. The description concerning the timing diagrams shown in the Fig. 5 to 7 is applicable to the first and second embodiments. The Fig. 5 to 7 illustrate, in order from an upper row to a lower row, an ON signal and an OFF signal applied to the positive switch 11, an ON signal and an OFF signal applied to the negative switch 12, a voltage of the brake coil 25 of the mechanical brake device 2, and a current flowing through the brake coil 25 of the mechanical brake device 2. Further, in the Fig. 5 to 7, as an example, assume that the brake operation processing is executed from the beginning at a time t11, the brake release processing starts at the time t11, and the brake release state is maintained at and after the time t11.

[0033] Fig. 5 is the timing chart illustrating each waveform when the positive switch and the negative switch of the brake driving device according to the first and second embodiments of the present disclosure are normal.

[0034] When the positive switch 11 and the negative switch 12 are normal, the positive switch 11 and the negative switch 12 perform the ON movement and the OFF movement according to the ON signal and the OFF signal output from the switch control unit 13.

[0035] When braking by the mechanical braking device 2 is applied (for example, from the beginning at time t11), the switch control unit 13 outputs the OFF signal to the positive switch 11 and the negative switch 12. The positive switch 11 and the negative switch 12, which have received the OFF signal from the switch control unit 13, perform the OFF movement and open the positive circuit 43N and the negative circuit 43N between the power supply 10 and the brake coil 25. In this way, a current 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). Since no electromagnetic force is generated in the brake coil 25, the armature 22 is strongly pressed against the friction plate 21 by a spring force of the spring 24, and braking by the mechanical braking device 2 is applied.

[0036] Brake release processing begins at time t11. The switch control unit 13 first outputs the ON signal to the positive switch 11 and the negative switch 12 at time t11. The positive switch 11 and the negative switch 12, having received the ON signal from the switch control unit 13, close the positive circuit 43P and the negative circuit 43N. In this way, the average voltage of the brake coil 25 is V1, the current (peak value is I1) flows from the power supply 10 to the brake coil 25, and an electromagnetic force that overcomes a spring force of the spring 24 for pressing the armature 22 against the friction plate 21 is generated in the core 26. The armature 22 is brought closer to the core 26 by the electromagnetic force, and the friction plate 21 is released from contacts with the armature 22 and the end plate 23.As a result, the friction plate 21 and therefore the shaft 31 of the motor can rotate freely, resulting in a condition in which braking is released for the motor.

[0037] At and after a time t12, the switch control unit 13 alternately switches and performs, for each predetermined time period T, between outputting the ON signal and the OFF signal subjected to PWM control for the positive switch 11 and outputting the ON signal and the OFF signal subjected to PWM control for the negative switch 12, to maintain the brake release state. For example, about 500 milliseconds is set as the predetermined time period T for performing PWM control, but one numerical value is only an example herein, and the other numerical value may be set. The predetermined time period T may be stored in a rewritable memory unit (not illustrated) and rewritable by an external device, and therefore can be changed to an appropriate value as needed even after the predetermined time period T is once set.

[0038] For example, for a switch having a higher failure probability of the positive switch 11 and the negative switch 12, if a longer time period than the predetermined time period T is set for performing PWM control, a failure of the switch having the higher failure probability can be predominantly monitored. For example, for a switch having better heat dissipation of the positive switch 11 and the negative switch 12, if a longer time period than the predetermined time period T is set for performing PWM control, heat generation by a switching movement of the switch having better heat dissipation can be suppressed.

[0039] To maintain the brake release state, the switch control unit 13 outputs the ON signal and the OFF signal subjected to PWM control to the positive switch 11, and outputs the ON signal to the negative switch 12 between time t12 and time t13, between time t14 and time t15, and between time t16 and time t17. The positive switch 11, having received the ON signal and the OFF signal subjected to PWM control by the switch control unit 13, performs the ON movement and the OFF movement, and closes and opens the positive circuit 43P between the power supply 10 and the brake coil 25. The negative switch 12, having received the ON signal from the switch control unit 13, closes the negative circuit 43N. In this way, the voltage of the brake coil 25 fluctuates between V1 and 0 (zero) in a floating manner.Further, an oscillation current smaller than the maximum value I1 of the brake coil current flows from the power supply 10 to the brake coil 25. A duty ratio used in PWM control is set to a size to an extent that an electromagnetic force overcoming a spring force of the spring 24 is generated, and therefore the brake release state in which the friction plate 21 is freed from contact with the armature 22 and the end plate 23 can be maintained.

[0040] To maintain the brake release state, the switch control unit 13 outputs the ON signal and the OFF signal to the positive switch 11, and outputs the ON signal and the OFF signal subjected to PWM control to the negative switch 12 between time t13 and time t14, between time t15 and time t16, and on and after time t17. The positive switch 11, having received the ON signal from the switch control unit 13, closes the positive circuit 43P. The negative switch 12, having received the ON signal and the OFF signal subjected to PWM control by the switch control unit 13, performs the ON movement and the OFF movement and closes and opens the negative circuit 43N between the power supply 10 and the brake coil 25. In this way, the voltage of the brake coil 25 fluctuates between V1 and 0 (zero) in a floating manner.Further, an oscillation current smaller than the maximum value I1 of the brake coil current flows from the power supply 10 to the brake coil 25. A duty ratio used in PWM control is set to a size to an extent that an electromagnetic force overcoming a spring force of the spring 24 is generated, and therefore the brake release state in which the friction plate 21 is freed from contact with the armature 22 and the end plate 23 can be maintained.

[0041] In such a manner, at and after the time t12 at which the brake release state is maintained, the switch control unit 13 switches and performs, for every predetermined period T, between outputting the ON signal and the OFF signal subjected to PWM control for the positive switch 11 and outputting the ON signal and the OFF signal subjected to PWM control for the negative switch 12. When the positive switch 11 and the negative switch 12 are normal, the positive switch 11 and the negative switch 12 perform the ON movement and the OFF movement according to the ON signal and the OFF signal subjected to PWM control alternately on the positive switch 11 and the negative switch 12, and therefore, the voltage and current of the brake coil 25 alternate in an oscillating manner.The detection unit 14 detects, as electrical information, the voltage applied to the brake coil 25 of the mechanical brake device 2 or the current flowing through the brake coil 25. The diagnosis unit 15 determines that both the positive switch 11 and the negative switch 12 are normal if the electrical information detected by the detection unit 14 always changes in an oscillating manner at and after the time t12 at which the switch control unit 13 alternately switches between and performs PWM control for performing ON / OFF control on the positive switch 11 and PWM control for performing ON / OFF control on the negative switch 12 for every predetermined period.

[0042] Fig. 6 is a timing chart illustrating each waveform when the positive switch and the brake driving device according to the first and second embodiments of the present disclosure experience a short circuit failure.

[0043] For example, when the positive switch 11 experiences a short-circuit failure and the negative switch 12 is normal, the positive switch 11 continues to perform the ON movement regardless of the ON signal and the OFF signal output from the switch control unit 13. Meanwhile, the negative switch 12, which is normal, performs the ON movement and the OFF movement according to the ON signal and the OFF signal output from the switch control unit 13.

[0044] When braking is applied by the mechanical braking device 2 (for example, from the beginning at time t11), the switch control unit 13 outputs the OFF signal to the positive switch 11 and the negative switch 12. The positive switch 11, which experiences a short-circuit failure, does not perform the OFF movement even if the positive switch 11 receives the OFF signal from the switch control unit 13, and the positive circuit 43P between the power supply 10 and the brake coil 25 remains closed. Meanwhile, the negative switch 12, which has received the OFF signal from the switch control unit 13, performs the OFF movement and opens the negative circuit 43N between the power supply 10 and the brake coil 25.Since the negative circuit 43N between the power supply 10 and the brake coil 25 is open, the current from the power supply 10 to the brake coil 25 is cut off, and therefore 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 a spring force of the spring 24, and braking by the mechanical brake device 2 is applied.

[0045] Brake release processing begins at time t11. The switch control unit 13 first outputs the ON signal to the positive switch 11 and the negative switch 12 at time t11. The positive switch 11 and the negative switch 12, having received the ON signal from the switch control unit 13, close the positive circuit 43P and the negative circuit 43N. In this way, the average voltage of the brake coil 25 is V1, the current (peak value is I1) flows from the power supply 10 to the brake coil 25, and an electromagnetic force that overcomes a spring force of the spring 24 for pressing the armature 22 against the friction plate 21 is generated in the core 26. The armature 22 is brought closer to the core 26 by the electromagnetic force, and the friction plate 21 is released from contacts with the armature 22 and the end plate 23.As a result, the friction plate 21 and therefore the shaft 31 of the motor can rotate freely, resulting in a condition in which braking is released for the motor.

[0046] At and after a time t12, the switch control unit 13 alternately switches and performs output of the ON signal and the OFF signal subjected to PWM control for the positive switch 11 and output of the ON signal and the OFF signal subjected to PWM control for the negative switch 12 for maintaining the brake release state for every predetermined period T.

[0047] In other words, the switch control unit 13 outputs the ON signal and the OFF signal subjected to PWM control to the positive switch 11 and outputs the ON signal to the negative switch 12 between time t12 and time t13, between time t14 and time t15, and between time t16 and time t17. Since the positive switch 11, which has received the ON signal and the OFF signal subjected to PWM control by the switch control unit 13, experiences a short-circuit failure, the positive circuit 43P between the power supply 10 and the brake coil 25 continues to be closed. The negative switch 12, which has received the ON signal from the switch control unit 13, closes the negative circuit 43N.During this time, therefore, both the positive switch 11 and the negative switch 12 are in a closed state similar to the time from time t11 to time t12, and a waveform F1 in which the voltage from the brake coil 25 is V1 and the current (the maximum value is I1) flows from the power supply 10 to the brake coil 25 appears. As described with reference to FIG. Fig. 5, when the positive switch 11 is normal, it is expected that the voltage of the brake coil 25 fluctuates between V1 and 0 (zero) in an oscillating manner in response to the ON signal and the OFF signal subjected to PWM control, and the oscillating current smaller than the peak value I1 of the brake coil current flows from the power supply 10 to the brake coil 25. However, the positive switch 11 experiences a short-circuit failure, and therefore, the waveform F1 appears in which the fixed voltage V1 is applied to the brake coil 25 and the fixed current I1 flows through the brake coil 25. Note that an electromagnetic force that overcomes a spring force of the spring 24 is generated, and therefore, the brake release state in which the friction plate 21 is released from contacts with the armature 22 and the end plate 23 can be maintained.

[0048] The switch control unit 13 outputs the ON signal to the positive switch 11 and outputs the ON signal and the OFF signal subjected to PWM control to the negative switch 12 between time t13 and time t14, between time t15 and time t16, and on and after time t17. The positive switch 11, having received the ON signal from the switch control unit 13, closes the positive circuit 43P. The negative switch 12, having received the ON signal and the OFF signal subjected to PWM control by the switch control unit 13, performs the ON movement and the OFF movement and closes and opens the negative circuit 43N between the power supply 10 and the brake coil 25.In this way, the voltage of the brake coil fluctuates between V1 and 0 (zero) in an oscillating manner, and the oscillating current smaller than the peak value I1 of the brake coil current flows from the power supply 10 to the brake coil 25. A duty ratio used in PWM control is set to a size to an extent that an electromagnetic force overcoming a spring force of the spring 24 is generated, and therefore the brake release state in which the friction plate 21 is freed from contact with the armature 22 and the end plate 23 can be maintained.

[0049] In such a manner, when the positive switch 11 undergoes a short-circuit failure at and after the time t12 at which an output of the ON signal and the OFF signal subjected to PWM control for the positive switch 11 and an output of the ON signal and the OFF signal subjected to PWM control for the negative switch 12 are alternately switched and performed for every predetermined period T, the waveform F1 appears in which the fixed voltage V1 is applied to the brake coil 25 and the fixed current I1 flows through the brake coil 25.Therefore, the diagnostic unit 15 determines that the positive switch 11 experiences a short-circuit failure when electricity information detected by the detection unit 14 detects a substantially fixed value equal to or greater than a prescribed first threshold while the ON signal and the OFF signal subjected to PWM control for the positive switch 11 are output (between time t12 and time t13, between time t14 and time t15, and between time t16 and time t17).Here, the first threshold value is set to a value (for example, a value lower by about 10% to about 20%) to a certain extent lower than a maximum voltage value that the brake coil voltage can assume when the electrical information is voltage, and the first threshold value is set to a value (for example, a value lower by about 10% to about 20%) to an extent lower than a maximum current value that the brake coil current can assume when the electrical information is current. The numerical example given herein is merely an example, and a different value may be set.Note that the first threshold value is stored in a rewritable storage unit (not illustrated) and is rewritable by an external device, and therefore can be changed to an appropriate value as needed even after the first threshold value has been set once.

[0050] The case where the positive switch 11 experiences a short-circuit failure is described above as an example in Fig. 6. The description in Fig. 6, in which the positive switch 11 is replaced by the negative switch 12, is applied to the description of a short-circuit failure in the negative switch 12. In other words, the diagnostic unit 15 determines that the negative switch 12 experiences a short-circuit failure when the electricity information detected by the detection unit 14 has a substantially fixed value equal to or more than the prescribed first threshold value while PWM control for performing ON / OFF control on the negative switch 12 is performed (between time t14, between time t15 and time t16, and at and after time t17).

[0051] Fig. 7 is a timing chart illustrating each waveform when the positive switch of the brake drive device according to the first and second embodiments of the present disclosure experiences an open circuit failure.

[0052] For example, when the positive switch 11 experiences an open circuit failure and the negative switch 12 is normal, the positive switch 11 continues to perform the OFF movement regardless of the ON signal and the OFF signal output from the switch control unit 13. Meanwhile, the negative switch 12, which is normal, performs the ON movement and the OFF movement according to the ON signal and the OFF signal output from the switch control unit 13.

[0053] When braking is applied by the mechanical brake device 2 (for example, from the beginning at time t11), the switch control unit 13 outputs the OFF signal to the positive switch 11 and the negative switch 12. Since the positive switch 11 experiences an open-circuit failure, the positive circuit 43P between the power supply 10 and the brake coil 25 continues to be open. Meanwhile, the negative switch 12, which has received the OFF signal from the switch control unit 13, performs the OFF movement and opens the negative circuit 43N between the power supply 10 and the brake coil 25. Since the negative circuit 43N between the power supply 10 and the brake coil 25 is open, the current from the power supply 10 to the brake coil 25 is cut off, and therefore 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 a spring force of the spring 24, and braking by the mechanical brake device 2 is operated.

[0054] Brake release processing begins at time t11. The switch control unit 13 first outputs the ON signal to the positive switch 11 and the negative switch 12 at time t11. The negative switch 12, having received the ON signal from the switch control unit 13, closes the negative circuit 43N between the power supply 10 and the brake coil 25. However, the positive switch 11 experiences an open-circuit failure, and therefore, the positive switch 11 does not perform the ON movement, and the positive circuit between the power supply 10 and the brake coil 25 remains open. Therefore, the current from the power supply 10 to the brake coil 25 is turned off, and accordingly, 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 a spring force of the spring 24, and the braking by the mechanical brake device 2 continues to be operated.

[0055] At and after a time t12, the switch control unit 13 switches and performs, for every predetermined time period T, between outputting the ON signal and the OFF signal subjected to PWM control for the positive switch 11 and outputting the ON signal and the OFF signal subjected to PWM control for the negative switch 12.

[0056] In other words, the switch control unit 13 outputs the on signal and off signal subjected to PWM control to the positive switch 11 and outputs the on signal to the negative switch 12 between time t12 and time t13, between time t14 and time t15, and between time t16 and time t17. Since the positive switch 11, which has received the on signal and off signal subjected to PWM control by the switch control unit 13, experiences an open circuit failure, the positive switch 11 does not perform the on movement, and the positive circuit 43P between the power supply 10 and the brake coil 25 continues to remain open. Furthermore, the negative switch 12, which has received the on signal from the switch control unit 13, closes the negative circuit 43N between the power supply 10 and the brake coil 25.During this time, the positive switch 11 and the negative switch 12 are in an open state, and a waveform F2 in which both the voltage and the current of the brake coil 25 are 0 appears.

[0057] The switch control unit 13 outputs the ON signal to the positive switch 11 and outputs the ON signal and the OFF signal subjected to PWM control to the negative switch 12 between time t13 and time t14, between time t15 and time t16, and on and after time t17. The negative switch 12, having received the ON signal and the OFF signal subjected to PWM control by the switch control unit 13, performs the ON movement and the OFF movement, and closes and opens the negative circuit 43N between the power supply 10 and the brake coil 25. Since the positive switch 11 experiences an open-circuit failure, the positive circuit 43P between the power supply 10 and the brake coil 25 continues to be open.During this time, the positive switch 11 and the negative switch 12 are therefore in an open state, and a waveform F2 in which both the voltage and the current of the brake coil 25 are 0 appears.

[0058] As with reference to Fig. 5, when the positive switch 11 is normal, it is expected that the voltage of the brake coil 25 fluctuates between V1 and 0 (zero) in an oscillating manner in response to the ON signal and the OFF signal subjected to PWM control, and the oscillating current smaller than the peak value I1 of the brake coil current from the power supply 10 flows to the brake coil 25. However, the positive switch 11 experiences open circuit failure, and therefore, the waveform F2 in which both the voltage and current of the brake coil 25 are 0 always appears.Therefore, the diagnostic unit 15 determines that at least one of the positive switch 11 and the negative switch 12 experiences an open circuit failure when electricity information detected by the detection unit 14 has a substantially fixed value equal to or less than a prescribed second threshold while the switch control unit 13 outputs an ON signal and the UP signal subjected to PWM control for the positive switch 11 (between time t12 and time t13, between time t14 and time t15, and between time t16 and time t17), and while the switch control unit 13 outputs the ON signal and the OFF signal subjected to PWM control for the negative switch 12 (between time t13 and time t14, between time t15 and time t16, and at and after time t17).Here, the second threshold is set to a positive value close to 0 volts when the electrical information is voltage, and the second threshold is set to a positive value close to 0 amperes when the electrical information is current. The numerical example given herein is merely an example, and a different value may be set. Note that the second threshold is stored in a rewritable storage unit (not illustrated) and is rewritable by an external device, and therefore can be changed to an appropriate value as needed even after the second threshold has been set once.

[0059] The case where the positive switch 11 experiences an open circuit failure is described above as the example in Fig. 7. The description in Fig. 7, in which the positive switch 11 is replaced by the negative switch 12, is replaced by the description of an open circuit failure in the negative switch 12.

[0060] However, if the negative switch 12 experiences an open circuit failure, the waveform F2 always appears, as in Fig. 7, both the voltage and current of the brake coil 25 are 0. In other words, when the positive switch 11 experiences an open circuit failure and when the negative switch 12 experiences an open circuit failure, the waveform F2 appears in which both the voltage and current of the brake coil 25 are 0. Therefore, from the waveform F2 in which both the voltage and current of the brake coil 25 are 0, it cannot be distinguished whether the positive switch 11 experiences an open circuit failure, the negative switch 12 experiences an open circuit failure, or both the positive switch 11 and the negative switch 12 are faulty due to an open circuit.The diagnostic unit 15 determines that at least one of the positive switch 11 and the negative switch 12 experiences an open circuit failure when electricity information detected by the detection unit 14 has a substantially fixed value equal to or less than the second threshold.

[0061] Fig. 8 is a flowchart illustrating a movement related to a fault diagnosis in the brake drive device according to the first embodiment of the present disclosure. Herein, as an example, it is assumed that electrical information detected by the detection unit 14 is a voltage applied to the brake coil 25. When it is assumed that electrical information detected by the detection unit 14 is a current flowing through the brake coil 25, the flowchart shown in Fig. 8, by replacing “voltage applied to the brake coil 25” with “current flowing through the brake coil 25”.

[0062] In step S101, the switch control unit 13 and the diagnostic 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 brake application state, the processing returns to step S101. At a time point when it is determined that the mechanical brake device 2 is in the brake release state, the switch control unit 13 first outputs the ON signal to the positive switch 11 and the negative switch 12 at a time point of brake release start, and then the processing proceeds to step S102.

[0063] In step S102, the switch control unit 13 alternately switches and performs, for every predetermined period of time, outputting the ON signal and the OFF signal subjected to PWM control for the positive switch 11 and outputting the ON signal and the OFF signal subjected to PWM control for the negative switch 12. The switch control unit 13 outputs an ON signal to the negative switch 12 while outputting the ON signal and the OFF signal subjected to PWM control for the positive switch 11. Further, the switch control unit 13 outputs the ON signal to the positive switch 11 while outputting the ON signal and the OFF signal subjected to PWM control for the positive switch 12.

[0064] In step S103, the detection unit 14 detects a brake coil voltage. Information about the detected brake coil voltage is transmitted to the diagnostic unit 15.

[0065] In step S104, the diagnostic unit 15 determines whether the brake coil voltage has a substantially fixed value equal to or more than the first threshold value.

[0066] If it is determined in step S104 that the voltage applied to the brake coil 25 has a substantially fixed value equal to or more than the first threshold, the processing proceeds to step S106. In step S106, the diagnostic unit 15 determines that the positive switch 11 is experiencing a short-circuit failure when, in step S104, the diagnostic unit 15 determines that the brake coil voltage detected by the detection unit 14 has a substantially fixed value equal to or more than the first threshold while the ON signal and the OFF signal subjected to PWM control for the positive switch 11 are output.Further, at step S106, the diagnostic unit 15 determines that the negative switch 12 is experiencing a short-circuit failure when, at step S104, the diagnostic unit 15 determines that the brake coil voltage detected by the detection unit 14 has a substantially fixed value equal to or greater than the first threshold while the ON signal and the OFF signal subjected to PWM control for the positive switch 12 are output. After step S106, the processing returns to step S101.

[0067] If it is not determined in step S104 that the voltage applied to the brake coil 25 has a substantially fixed value equal to or greater than the first threshold, processing proceeds to step S105. In step S105, the diagnostic unit 15 determines whether the brake coil voltage has a substantially fixed value equal to or greater than the first threshold.

[0068] If it is determined in step S105 that the brake coil voltage has a substantially fixed value equal to or less than the second threshold, processing proceeds to step S108. In step S108, the diagnostic unit 15 determines that at least one of the positive switch 11 and the negative switch 12 is experiencing an open circuit failure. After step S108, processing returns to step S101.

[0069] If it is not determined in step S105 that the brake coil voltage has a substantially fixed value equal to or less than the second threshold, processing proceeds to step S107. In step S107, the diagnostic unit 15 determines that both the positive switch 11 and the negative switch 12 are normal. After step S107, processing returns to step S101.

[0070] Note that the processing in step S104 and the processing in step S105 are executed in a switched order.

[0071] According to the first embodiment of the present disclosure, while performing PWM control for the positive switch 11 and the negative switch 12 in the brake release state, diagnosis of a malfunction in the positive switch 11 and the negative switch 12 can be easily performed by the diagnosis unit 15. Moreover, by performing PWM control for the positive switch 11 and the negative switch in the brake release state, the brake release state is maintained with less power than that at the time of the brake release state, and therefore, the size and heat generation of the mechanical brake device 2 can be reduced. <Konfiguration der Bremsantriebsvorrichtung gemäß der zweiten Ausführungsform>

[0072] Fig. 9 is a circuit diagram illustrating the brake driving device according to the second embodiment of the present disclosure.

[0073] In the first embodiment described with reference to the Fig. 1 to 8, diagnostic processing is performed by the diagnostic unit 15 based on electricity information detected by the detection circuit 14. In the second embodiment, a display unit 17 configured to display electricity information detected by the detection unit 14 is provided instead of the diagnostic unit 15 and the alarm output unit 16 in Fig. 1 provided.

[0074] As in Fig. 9, a brake drive device 1 according to the second embodiment of the present disclosure includes a power supply 10, a positive switch 11, a negative switch 12, a switch control unit 13, a detection unit 14, the display unit 17, and a surge absorber 18. Fig. 9 illustrates only one brake coil 25 for a mechanical braking device 2 controlled by the brake drive device 1.

[0075] The mechanical braking device 2, the power supply 10, the positive switch 11, the negative switch 12, the switch control unit 13, the detection unit 14 and the surge arrester 18 are as described with reference to the Fig. 1 to 9 in the first embodiment.

[0076] The display unit 17 displays electricity information acquired by the detection unit 14, while the switch control unit 13 switches and performs, for every predetermined period, between outputting the ON signal and the OFF signal subjected to PWM control for the positive switch 11 and outputting the ON signal and the OFF signal subjected to PWM control for the negative switch 12. As an example of the display unit 17, there are a single display device, a display device attached to the brake drive device 1 or a motor drive device including the brake drive device 1, a display device attached to a personal computer and a portable terminal, and the like. <Bewegung der Bremsantriebsvorrichtung gemäß der zweiten Ausführungsform>

[0077] The description concerning the timing diagrams shown in the Fig. 5 to 7 is also applicable to the second embodiment.

[0078] Fig. 10 is a flowchart illustrating a movement related to a fault diagnosis in the brake drive device according to the second embodiment of the present disclosure. Herein, as an example, it is assumed that electrical information detected by the detection unit 14 is a voltage applied to the brake coil 25. When it is assumed that electrical information detected by the detection unit 14 is a current flowing through the brake coil 25, the flowchart shown in Fig. 10, by replacing “voltage applied to the brake coil 25” with “current 15 flowing through the brake coil”.

[0079] In step S201, the switch control unit 13 determines 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 brake application state, the processing returns to step S201. At a time point when it is determined that the mechanical brake device 2 is in the brake release state, the switch control unit 13 first outputs the on signal to the positive switch 11 and the negative switch 12 at a time point of starting the brake release, and then the processing proceeds to step S102.

[0080] At and after a time S202, the switch control unit 13 switches for every predetermined period of time T and outputs the on signal and the off signal subjected to PWM control for the positive switch 11 and the on signal and the off signal subjected to PWM control for the negative switch 12. The switch control unit 13 outputs an on signal to the negative switch 12, while the switch control unit 13 outputs the on signal and the off signal subjected to PWM control for the positive switch 11. Further, the switch control unit 13 outputs the on signal to the positive switch 11, while the switch control unit 13 outputs the on signal and the off signal subjected to PWM control for the positive switch 12.

[0081] In step S203, the detection unit 14 detects a brake coil voltage. Information about the detected brake coil voltage is transmitted to the display unit 17.

[0082] In step S203, the display unit 17 displays a brake coil voltage.

[0083] As in the Fig. 4 and Fig.6, the display unit 17 displays, for example, the brake coil voltage detected by the detection unit 14, while the switch control unit 13 controls and performs PWM control for each predetermined period between an output of the ON signal and the OFF signal that are subjected to PWM control for the positive switch 11 and an output of the ON signal and the OFF signal that are subjected to PWM control for the negative switch 12. By confirming a display content of the display unit 17, an operator can determine whether the positive switch 11 and the negative switch 12 are normal, the positive switch 11 is experiencing a short-circuit failure, the negative switch is experiencing a short-circuit failure, or at least one of the positive switch 11 and the negative switch is experiencing an open-circuit failure.

[0084] According to the second embodiment of the present disclosure, an operator can easily diagnose a failure of the positive switch 11 and the negative switch 12 based on a display content of electricity information about the brake coil 25 of the mechanical brake device 2 by the display unit 17 while performing PWM control for the positive switch 11 and PWM control for the negative switch in the brake release state. Moreover, by performing PWM control for the positive switch 11 and PWM control for the negative switch in the brake release state, the brake release state is maintained with less power than that at the time of the brake release state, and therefore, the size and heat generation of the mechanical brake device 2 can be reduced. <Erreichen sowohl der Störungsdiagnose als auch der Verringerung der Größe und Wärmeerzeugung der mechanischen Bremsvorrichtung>

[0085] According to the first and second embodiments of the present disclosure, by performing PWM control for the positive switch 11 and PWM control for the negative switch in the brake release state, a diagnosis of a failure of the positive switch 11 and the negative switch 12 can be easily performed, and the size and heat generation of the mechanical brake device 2 can also be reduced.

[0086] Although the present disclosure is described above in detail, the present disclosure is not limited to the individual embodiments described above. Various types of addition, replacement, modification, partial omission, and the like can be made to the embodiments without departing from the purpose of the present disclosure or without departing from the purpose described in the claims and the scope of the present disclosure derived from equivalents thereof. The embodiments can also be carried out in combination. In the embodiments described above, for example, an order of operations and an order of processing parts are given as an example, which is not limited thereto. Furthermore, this also applies to a case where a numerical value or a numerical expression is used in the description of the embodiments described above. <Ergänzender Hinweis>

[0087] With regard to the embodiments and modification examples described above, additional information is disclosed below. [Supplementary Note 1]

[0088] A brake drive device 1 comprising: a positive switch 11 configured to close a positive circuit between a positive terminal 41P of a power supply 10 and a positive terminal 42P of a non-energizing operation type mechanical braking device 2 by performing an ON movement, and to open the positive circuit 43P by performing an OFF movement; a negative switch 12 configured to close a negative circuit 42N between a negative terminal 41N of the power supply 10 and a negative terminal 42N of the mechanical braking device 2 by performing the ON movement and to open the negative circuit 43N by performing the OFF movement; and a switch control unit 13 configured to output to the positive switch 11 and the negative switch 12 an ON signal to cause the ON movement to be performed and an OFF signal to cause the OFF movement to be performed, wherein the switch control unit 13, when a brake is applied by the mechanical braking device 2, outputs the OFF signal to the positive switch 11 and the negative switch 12 and, when the braking by the mechanical braking device 2 is released, outputs the ON signal to the positive switch 11 and the negative switch 12 at a time of brake release start, and then alternately switches between outputting the ON signal and the OFF signal subjected to PWM control for the positive switch 11 and outputting the ON signal and the OFF signal subjected to PWM control for the negative switch 12 for every predetermined period of time and performs them while maintaining release of the braking by the mechanical braking device 2. [Supplementary Note 2]

[0089] The brake drive device 1 according to Supplementary Note 1, wherein the switch control unit 13 outputs the ON signal to the negative switch 12 while the switch control unit 13 outputs the ON signal and the OFF signal subjected to PWM control for the positive switch 11, and the switch control unit 13 outputs the ON signal to the positive switch 11 while the control switch unit 13 outputs the ON signal and the OFF signal subjected to PWM control for the negative switch 12. [Supplementary Note 3]

[0090] Brake drive device 1 according to supplementary note 2, further comprising: a detection unit 14 configured to detect electrical information of 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; and a diagnosis unit 15 configured to make a diagnosis of presence or absence of a fault in the positive switch 11 and the negative switch 12 based on electricity information detected by the detection unit 14, while the switch control unit 13 switches and performs, for every predetermined period of time, between outputting the ON signal and the OFF signal subjected to PWM control for the positive switch 11 and outputting the ON signal and the OFF signal subjected to PWM control for the negative switch 12. [Supplementary Note 4]

[0091] Brake drive device 1 according to supplementary note 3, wherein the diagnostic unit 15 determines that the positive switch 11 experiences a short-circuit failure when the electricity information detected by the detection unit 14 has a substantially fixed value equal to or more than a prescribed first threshold value while the switch control unit 13 outputs the ON signal and the OFF signal subjected to PWM control for the positive switch 11, and determines that the negative switch 12 experiences a short-circuit failure when the electricity information detected by the detection unit 14 has a substantially fixed value equal to or more than the first threshold value while the switch control unit 13 outputs the ON signal and the OFF signal subjected to PWM control for the negative switch 12. [Supplementary Note 5]

[0092] Brake drive device 1 according to supplementary note 3, wherein the diagnostic unit 15 determines that at least one of the positive switch 11 and the negative switch 12 experiences an open circuit failure when the electricity information detected by the detection unit 14 has a substantially fixed value equal to or lower than a prescribed second threshold value, while the switch control unit 13 outputs the ON signal and the OFF signal subjected to PWM control for the positive switch 11, and while the switch control unit 13 outputs the ON signal and the OFF signal subjected to PWM control for the negative switch 12. [Supplementary Note 6]

[0093] Brake drive device 1 according to supplementary note 3, further comprising the following an alarm output unit configured to output an alarm when the diagnostic unit 15 determines that at least one of the positive switch 11 and the negative switch 12 is faulty. [Supplementary Note 7]

[0094] Brake drive device 1 according to supplementary note 2, further comprising: a detection unit 14 configured to detect electricity information that 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; and a display unit 17 configured to display and perform the electricity information detected by the detection unit 14 while the switch control unit 13 alternately switches between outputting the ON signal and the OFF signal subjected to PWM control for the positive switch 11 and outputting the ON signal and the OFF signal subjected to PWM control for the negative switch 12 for every predetermined period of time. [Supplementary Note 8]

[0095] Brake drive device 1 according to one of the supplementary notes 1 to 7, wherein the mechanical braking device 2 applies a brake to a motor by a spring force of a spring 24 pressing an armature 22 against a friction plate 21 to which a shaft 31 of the motor is coupled, and releases the braking on the motor by separating the armature 22 from the friction plate 21 by an electromagnetic force generated by a current flowing through the brake coil 25. LIST OF REFERENCE SYMBOLS 1 brake drive device 2 Mechanical braking device 10 Power supply 11 Positive switch 12 Negative switch 13 Switch control unit 14 Recording unit 15 Diagnostic unit 16 Alarm output unit 17 Display unit 18 surge arresters 21 Friction plate 22 anchors 23 End plate 24 springs 25 brake coil 26 core 27 spacers 28 bolts 31 Wave 32 Hub 41P Positive terminal of the power supply 41N Negative terminal of the power supply 42P Positive terminal of the mechanical brake device 42N Negative clamp of the mechanical brake device 43P Positive circuit 43N Negative circuit QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2019-119530A

[0002] JP 2011-195287A

[0002] JP 2007-143311A

[0002] JP H08-182365A

[0002]

Claims

[1] Brake drive device comprising: a positive switch configured to close a positive circuit between a positive terminal of a power supply and a positive terminal of a non-energizing actuation type mechanical braking device by performing an ON movement, and to open the positive circuit by performing an OFF movement; a negative switch configured to close a negative circuit between a negative terminal of the power supply and a negative terminal of the mechanical braking device by performing the ON movement and to open the negative circuit by performing the OFF movement; and a switch control unit configured to output to the positive switch and the negative switch an ON signal to cause the ON movement to be performed and an OFF signal to cause the OFF movement to be performed, wherein the switch control unit, when a brake is applied by the mechanical braking device, outputs the OFF signal to the positive switch and the negative switch and, when the brake is released by the mechanical brake device, outputs the ON signal to the positive switch and the negative switch at a time of brake release start, and then alternately switches between outputting the ON signal and the OFF signal subjected to PWM control for the positive switch and outputting the ON signal and the OFF signal subjected to PWM control for the negative switch for every predetermined period of time and performs them while maintaining release of the brake by the mechanical brake device. [2] The brake drive device according to claim 1, wherein the switch control unit outputs the ON signal to the negative switch while the switch control unit outputs the ON signal and the OFF signal subjected to PWM control for the positive switch, and the switch control unit outputs the ON signal to the positive switch while the control switch unit outputs the ON signal and the OFF signal subjected to PWM control for the negative switch. [3] A brake drive device according to claim 2, further comprising: a detection unit configured to detect electricity information of at least one of a voltage applied to a brake coil of the mechanical brake device and a current flowing through the brake coil; and a diagnosis unit configured to make a diagnosis of presence or absence of a fault in the positive switch and the negative switch based on electricity information detected by the detection unit, while the switch control unit switches between and performs output of the ON signal and the OFF signal subjected to PWM control for the positive switch and output of the ON signal and the OFF signal subjected to PWM control for the negative switch every predetermined period of time. [4] Brake drive device according to claim 3, wherein the diagnostic unit determines that the positive switch experiences a short-circuit failure when the electricity information detected by the detection unit has a substantially fixed value equal to or more than a prescribed first threshold value while the switch control unit outputs the ON signal and the OFF signal subjected to PWM control for the positive switch, and determines that the negative switch experiences a short-circuit failure when the electricity information detected by the detection unit has a substantially fixed value equal to or more than the first threshold value while the switch control unit outputs the ON signal and the OFF signal subjected to PWM control for the negative switch. [5] The brake drive device according to claim 3, wherein the diagnosis unit determines that at least one of the positive switch and the negative switch experiences an open circuit failure when the electricity information detected by the detection unit has a substantially fixed value equal to or lower than a prescribed second threshold value while the switch control unit outputs the ON signal and the OFF signal subjected to PWM control for the positive switch, and while the switch control unit outputs the ON signal and the OFF signal subjected to PWM control for the negative switch. [6] The brake drive device according to claim 3, further comprising an alarm output unit configured to output an alarm when the diagnostic unit determines that at least one of the positive switch and the negative switch is malfunctioning. [7] A brake drive device according to claim 2, further comprising: a detection unit configured to detect electricity information that 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; and a display unit configured to display and perform the electricity information detected by the detection unit while the switch control unit alternately switches between outputting the ON signal and the OFF signal subjected to PWM control for the positive switch and outputting the ON signal and the OFF signal subjected to PWM control for the negative switch for every predetermined period of time. [8] A brake drive device according to any one of claims 1 to 7, wherein the mechanical brake device applies a brake to a motor by an elastic force of a spring pressing an armature against a friction plate to which a shaft of the motor is coupled, and releases the brake on the motor by separating the armature from the friction plate by an electromagnetic force generated by a current flowing through the brake coil.

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