Explosion-proof system

Abstract

The present invention provides a highly reliable explosion-proof system 1 while suppressing manufacturing costs. This explosion-proof system 1 comprises a motor drive circuit 20 electrically connected to the exterior of an internal pressure explosion-proof structure for the purpose of controlling and / or driving a motor part, and has a circuit that electrically insulates the motor drive circuit 20 on the input side for a control signal to the motor drive circuit 20 and on the supply side of a power source to the motor drive circuit 20.

Description

Explosion-proof system

[0001] The present disclosure relates to an explosion-proof system.

[0002] Regarding an explosion-proof system, for example, Patent Document 1 proposes a technique for electrically insulating a motor drive circuit in an explosion-proof system in which a motor unit is disposed inside an internal pressure explosion-proof structure.

[0003] Japanese Patent Application Laid-Open No. 2013-111697

[0004] In a conventional explosion-proof system, in order to cut off the energy supply to a robot before the completion of internal pressure application for internal pressure explosion protection, for example, the motor power is separated upstream of a servo amplifier in a motor control device, and the motor control signal is separated downstream of the servo amplifier in the motor control device.

[0005] In a conventional explosion-proof system, since the motor control signal is separated downstream of the servo amplifier, it is necessary to增设 additional separation means as the number of control axes of the motor increases. Also, generally, contacts are often used for the separation means. Therefore, in a conventional explosion-proof system, a decrease in contact reliability is likely to occur. Accordingly, an object of the present disclosure is to provide a highly reliable explosion-proof system while suppressing manufacturing costs.

[0006] The explosion-proof system of the present disclosure is an explosion-proof system including a motor unit inside an internal pressure explosion-proof structure, or an explosion-proof system including a motor drive circuit and a motor unit inside an internal pressure explosion-proof structure, and includes a motor drive circuit electrically connected to the outside of the internal pressure explosion-proof structure for at least one of control and driving of the motor unit, and a circuit for electrically insulating the motor drive circuit on an input side of a control signal to the motor drive circuit and a power supply side of the motor drive circuit.

[0007] According to the explosion-proof system of the present disclosure, a highly reliable explosion-proof system can be provided while suppressing manufacturing costs.

[0008] FIG. 1 is a diagram showing an explosion-proof system according to an embodiment of the present disclosure. FIG. 2 is a diagram showing a conventional explosion-proof system. FIG. 3 is a diagram showing an explosion-proof system according to another embodiment of the present disclosure.

[0009] The embodiments for implementing this disclosure will be described with reference to the drawings. However, this disclosure is not limited to the following embodiments. This disclosure can be implemented with appropriate modifications without departing from the spirit of this disclosure.

[0010] (Explosion-proof system) The explosion-proof system 1 of this disclosure will be explained using a painting robot as an example. Note that the painting robot is for illustrative purposes only. The explosion-proof system 1 of this disclosure can be applied to various industrial machines and the like.

[0011] Figure 1 is a diagram showing an overview of an explosion-proof system 1 according to an embodiment of the present disclosure. The explosion-proof system 1 comprises a motor drive circuit (MDC) 20, a painting robot housing (PRH) 40, an explosion-proof circuit (EPC) 60, and a power supply (EPS) 62 for the explosion-proof circuit.

[0012] (Painting robot housing) Inside the painting robot housing (PRH) 40, the parts that operate as a robot in the explosion-proof system 1, namely the painting unit, are arranged.

[0013] (Hazardous and Non-Hazardous Areas) The explosion-proof system 1 is divided into a non-hazardous area NHR and a hazardous area HR, with boundary line L10 as the dividing line. The side of boundary line L10 indicated by arrow A1 is the non-hazardous area NHR. The side of boundary line L10 indicated by arrow A2 is the hazardous area HR. The painting robot housing (PRH) 40 is included in the hazardous area HR. The parts of the explosion-proof system 1 other than the painting robot housing (PRH) 40 are included in the non-hazardous area NHR.

[0014] In the example shown in Figure 1, the motor unit (MU) 42, position detection circuit (PDC) 54, internal pressure sensor (IPS) 72, and flow sensor (FVS) 74 are arranged inside the painting robot housing (PRH) 40.

[0015] (Motor Unit) The motor unit (MU) 42 includes a position information communication unit (PCM) 44 and a power drive unit (PDU) 46. The position information communication unit (PCM) 44 is the part that communicates motor position information with the motor drive circuit (MDC) 20. Motor position information includes, for example, position information related to the motor shaft. The power drive unit (PDU) 46 is the part that receives power from the motor drive circuit (MDC) 20. Power can be received, for example, as a PWM (Pulse Width Modulation) signal.

[0016] (Position detection circuit) The position detection circuit (PDC) 54 includes a position memory device (PMD) 56. The position detection circuit (PDC) 54 may also be provided in the motor unit (MU) 42.

[0017] The position detection circuit (PDC) 54 is a circuit that detects the position of each axis of the motors that make up the robot. The position detection circuit (PDC) 54 includes, for example, a pulse coder.

[0018] The position memory device (PMD) 56 is a device that stores the position data of each axis of the motor detected by the position detection circuit (PDC) 54.

[0019] The position memory device (PMD) 56 of this embodiment can maintain the position of the motor shaft without receiving an external power supply. In other words, the position memory device (PMD) 56 can maintain position data without receiving an external power supply.

[0020] The position memory device (PMD) 56 can retain position data without receiving a power supply because the position detection circuit (PDC) 54 (pulse coder) is composed of a battery-less encoder. Because the position memory device (PMD) 56 can retain position data without receiving a power supply, an external battery for the position memory device (PMD) 56 to maintain its position is unnecessary. This is because even if the power supply from the motor drive circuit (MDC) 20 to the position detection circuit (PDC) 54 is turned off, there is no need to supply power to the position memory device (PMD) 56 from the battery.

[0021] The position detection circuit (PDC) 54 is a so-called battery-less type encoder. The battery-less encoder can be, for example, a mechanical type, or more specifically, a gear-type encoder.

[0022] It should be noted that battery-less encoders are not limited to mechanical types. Any type that can retain position data without receiving an external power supply can be used, such as magnetic encoders, those using non-volatile memory, or self-generating power systems.

[0023] (Internal Pressure Explosion-Proof Structure) The explosion-proof structure in explosion-proof system 1 will be described below. Explosion-proof system 1 includes, for example, robots or machines used in an explosive atmosphere, such as painting robots. The explosion-proof structure includes an internal pressure explosion-proof structure and an intrinsically safe explosion-proof structure.

[0024] First, let's explain the internal pressure explosion-proof structure. In explosion-proof system 1, the painting robot housing (PRH) 40 has an internal pressure explosion-proof structure.

[0025] The painting robot housing (PRH) 40 is equipped with an inlet 51 and a scavenging port 52. A protective gas is supplied into the interior of the painting robot housing (PRH) 40 from the inlet 51, as shown by arrow A51. The protective gas is a gas for internal pressure explosion prevention. The protective gas is, for example, air or nitrogen.

[0026] As protective gas is introduced into the painting robot housing (PRH) 40, the gas that filled the inside of the painting robot housing (PRH) 40 is scavenged through the scavenging port 52 as shown by arrow A52. As the introduction and scavenging progress, the gas inside the painting robot housing (PRH) 40 is approximately replaced by protective gas.

[0027] (Explosion-proof circuit and power supply for explosion-proof circuit) The explosion-proof circuit (EPC) 60 is a circuit that performs control related to the establishment of internal pressure explosion protection and intrinsically safe explosion protection. The power supply for the explosion-proof circuit (EPS) 62 is the part that supplies power related to the establishment of internal pressure explosion protection and intrinsically safe explosion protection. The power supply for the explosion-proof circuit (EPS) 62 supplies power PP (Power purge) for purging the painting robot housing (PRH) 40 in relation to the establishment of internal pressure explosion protection for the painting robot housing (PRH) 40.

[0028] (Internal pressure sensor and flow sensor) The explosion-proof circuit (EPC) 60 is connected to the internal pressure sensor (IPS) 72 via line LS1. The internal pressure sensor (IPS) 72 is a sensor that detects the pressure inside the painting robot housing (PRH) 40.

[0029] The explosion-proof circuit (EPC) 60 is connected to the flow sensor (FVS) 74 via line LS2. The flow sensor (FVS) 74 is a sensor that detects the flow rate of gas inside the painting robot housing (PRH) 40.

[0030] The explosion-proof circuit (EPC) 60 receives the pressure inside the painting robot housing (PRH) 40 detected by the internal pressure sensor (IPS) 72 as a sensor signal. The explosion-proof circuit (EPC) 60 also receives the gas flow rate inside the painting robot housing (PRH) 40 detected by the flow sensor (FVS) 74 as a sensor signal.

[0031] The explosion-proof circuit (EPC) 60 controls the supply of protective gas to the painting robot housing (PRH) 40, as shown in line L61. The explosion-proof circuit (EPC) 60 controls the supply of protective gas by referring to the internal pressure sensor (IPS) 72 and the sensor signals received from the internal pressure sensor (IPS) 72. By controlling the explosion-proof circuit (EPC) 60, the gas inside the painting robot housing (PRH) 40 is scavenged and replaced with protective gas, thereby establishing internal pressure explosion protection.

[0032] To evacuate the gas inside the painting robot housing (PRH) 40 and establish internal pressure explosion protection, the explosion-proof system 1 is equipped with a purge unit (not shown). Based on control from the explosion-proof circuit (EPC) 60, the purge unit replaces the protective gas inside the painting robot housing (PRH) 40.

[0033] (Motor drive circuit) The motor drive circuit (MDC) 20 is a circuit that drives the motor provided in the painting robot housing (PRH) 40. The motor drive circuit (MDC) 20 also functions as an amplifier.

[0034] The motor drive circuit (MDC) 20 includes a position information communication unit (PCD) 22 and a power supply unit (MPSU) 24. Figure 1 illustrates a case where six motors M are provided in the motor unit (MU) 42, corresponding to six axes. In the motor drive circuit (MDC) 20, M(J1) indicates the motor corresponding to the first axis. Similarly, M(J6) indicates the motor corresponding to the sixth axis. In Figure 1, the descriptions of M(J2) to M(J5) are omitted.

[0035] (Position information communication unit on the motor drive circuit side) The position information communication unit (PCD) 22 on the motor drive circuit (MDC) 20 side is the part that communicates position information with the position information communication unit (PCM) 44 on the painting robot housing (PRH) 40 side.

[0036] The position information communication unit (PCD) 22 communicates with the position information communication unit (PCM) 44 of the motor unit (MU) 42 for each motor M, for example, regarding DV (Drive Voltage: voltage supplied to the motor) / RV (Reference Voltage: voltage that serves as the reference for position information). This communication is performed via a communication line. In Figure 1, the communication line for M(J1) is shown as communication line LM1, and the communication line for M(J6) is shown as communication line LM6. Similar communication lines are provided for the other motors.

[0037] (Power supply unit) The power supply unit (MPSU) 24 is the part that supplies power to the power drive unit (PDU) 46 of the motor unit (MU) 42. The power supply unit (MPSU) 24 is also called the PWM (Pulse Width Modulation) control unit.

[0038] The power supply unit (MPSU) 24 transmits, for example, PWM control signals for each motor M, such as U (operated variable), V (speed), W (angular velocity), and G (gain), to the power drive unit (PDU) 46 of the motor unit (MU) 42. This transmission is performed via a power line. In Figure 1, the power line for M(J1) is shown as power line LM11, and the power line for M(J6) is shown as power line LM16. Similar power lines are provided for the other motors. Note that DCP in Figure 1 indicates Duty Cycle Positive, and DCN indicates Duty Cycle Negative.

[0039] (Explosion-proof control) The establishment of explosion-proof safety in the explosion-proof system 1 of this embodiment will be described. In the explosion-proof system 1 of this embodiment, first, the internal pressure explosion-proof structure of the painting robot housing (PRH) 40 located in the hazardous area HR is established. Then, after the internal pressure explosion-proof structure is established, the motor drive circuit (MDC) 20 is energized. The following will be explained in order.

[0040] (Isolation Circuit) Until the internal pressure explosion-proof structure of the painting robot housing (PRH) 40 is established, the circuit used to disconnect circuits such as the motor drive circuit (MDC) 20 from the power supply is called an isolation circuit. Isolation refers to electrical isolation and means the interruption of electrical energy. The explosion-proof system 1 is equipped with two isolation circuits: a first isolation circuit (ICC) 31 and a second isolation circuit (ICP) 32.

[0041] The first isolation circuit (ICC) 31 is an isolation circuit relating to the signal line. In other words, the first isolation circuit (ICC) 31 is an isolation circuit for the communication system or control system.

[0042] The second isolation circuit (ICP) 32 is an isolation circuit related to the power line. In other words, the second isolation circuit (ICP) 32 is an isolation circuit for the power system.

[0043] In the explosion-proof system 1 of the present embodiment, both the first insulation circuit (ICC) 31 and the second insulation circuit (ICP) 32 are provided on the front stage side of the motor drive circuit (MDC) 20.

[0044] (Conventional explosion-proof system) Here, the conventional explosion-proof system 101 will be described with reference to FIG. 2. FIG. 2 is a diagram showing the conventional explosion-proof system 101. In the following description, mainly the matters different from the explosion-proof system 1 of the present embodiment will be described with respect to the conventional explosion-proof system 101.

[0045] In the conventional explosion-proof system 101, the first insulation circuit (ICC) is provided on the rear stage side of the motor drive circuit (MDC) 20. Specifically, six first insulation circuits (ICC) 311 to 316 are arranged between the motor drive circuit (MDC) 20 and the painting robot housing (PRH) 40. More specifically, the six first insulation circuits (ICC) 311 to 316 are provided between the position information communication unit (PCD) 22 on the motor drive circuit (MDC) 20 side and the position information communication unit (PCM) 44 on the painting robot housing (PRH) 40 side.

[0046] In the conventional explosion-proof system 101, the position storage device (PMD) 561 provided in the position detection circuit (PDC) 54 of the painting robot housing (PRH) 40 is not battery-less. In order for the position storage device (PMD) 561 to hold position data, it is necessary to supply power to the position storage device (PMD) 561. Therefore, a battery (not shown) is connected to the position storage device (PMD) 561.

[0047] When a battery is connected to the position storage device (PMD) 561, the position storage device (PMD) 561 becomes an intrinsically safe circuit. Therefore, in order to suppress it below the maximum external inductance and maximum external capacitance defined for intrinsically safe related equipment, it is necessary to disconnect the position information communication unit (PCM) 44 on the painting robot housing (PRH) 40 side from the motor drive circuit (MDC) 20 and the like. Therefore, as shown in FIG. 2, in the conventional explosion-proof system 101, an insulation circuit is arranged on the rear stage side of the motor drive circuit (MDC) 20, that is, between the motor drive circuit (MDC) 20 and the painting robot housing (PRH) 40.

[0048] In contrast, in the explosion-proof system 1 of the present embodiment shown in FIG. 1, like the second insulation circuit (ICP) 32, the first insulation circuit (ICC) 31 is also provided on the front stage side of the motor drive circuit (MDC) 20. Unlike the conventional position memory device (PMD) 561, a battery is not connected to the position memory device (PMD) 56 of the present embodiment. Therefore, it is not necessary to disconnect the position information communication unit (PCM) 44 on the side of the painting robot housing (PRH) 40 from the motor drive circuit (MDC) 20 or the like.

[0049] Further, in the conventional explosion-proof system 101, six first insulation circuits (ICC) are provided from the first insulation circuit (ICC) 311 to the first insulation circuit (ICC) 316. This is because it is necessary to provide the first insulation circuit (ICC) for each communication line LM of each motor M. For example, when the motor has six axes, six insulation circuits are arranged.

[0050] In contrast, in the explosion-proof system 1 of the present embodiment, only one first insulation circuit (ICC) is provided, which is the first insulation circuit (ICC) 31. In the explosion-proof system 1 of the present embodiment, the first insulation circuit (ICC) 31 is provided on the front stage side of the motor drive circuit (MDC) 20. Therefore, it is not necessary to provide the first insulation circuit (ICC) 31 for each communication line LM of each motor M. Hereinafter, the explosion-proof system 1 of the present embodiment will be specifically described.

[0051] As shown in FIG. 1, in the non-dangerous area NHR of the explosion-proof system 1 of the present embodiment, in addition to the motor drive circuit (MDC) 20, the explosion-proof circuit (EPC) 60, and the explosion-proof circuit power supply (EPS) 62, an AC power supply 10, a power supply unit (PSU) 12, a control unit (CU) 14, and a display / operation unit (DCU) 16 are provided.

[0052] (AC Power Supply) The AC power supply 10 is connected to the power supply unit (PSU) 12 via lines L11 and L12. The AC power supply 10 is also connected to the explosion-proof circuit power supply (EPS) 62 via lines L67 and L68. The explosion-proof circuit power supply (EPS) 62 supplies power PP (Power purge) for purging the painting robot housing (PRH) 40, as described above. On the other hand, the power supply unit (PSU) 12 supplies power PC (Power control) for controlling the explosion-proof system 1.

[0053] (Power supply for explosion-proof circuit) The power supply for the explosion-proof circuit (EPS) 62 is a power supply independent of the power supply for the control unit (CU) 14 and the power supply for the motor drive circuit (MDC) 20. In other words, the power supply for the explosion-proof circuit (EPS) 62 can be turned on and off independently of the power supply unit (PSU) 12.

[0054] By having a separate power supply system for the explosion-proof system 1 from the power supply unit (PSU) 12, it becomes possible to monitor the internal pressure state of the painting robot housing (PRH) 40 in the explosion-proof circuit (EPC) 60, and to disconnect the isolation circuit if an abnormality occurs in the painting robot housing (PRH) 40, etc., even when the power supply unit (PSU) 12 is off or temporarily off. In other words, even when the power supply unit (PSU) 12 is off, it becomes possible to monitor sensor signals and control the isolation circuit by the explosion-proof circuit (EPC) 60.

[0055] (Power Supply Unit) The power supply unit (PSU) 12 is the part that supplies power to the motor drive circuit (MDC) 20 and the control unit (CU) 14. As described above, the power supply unit (PSU) 12 can be turned on and off independently of the explosion-proof circuit power supply (EPS) 62.

[0056] Furthermore, an explosion-proof circuit (EPC) 60 is connected to the power supply unit (PSU) 12 via line L63. The power supply unit (PSU) 12 has an off / on function that allows it to be turned on / off by control of the explosion-proof circuit (EPC) 60. Alternatively, the power supply unit (PSU) 12 may be connected to a control unit (CU) 14, and the power supply unit (PSU) may have an off / on function that allows it to be turned on / off by control of the control unit (CU) 14. In this case, if the explosion-proof circuit (EPC) 60 and the control unit (CU) 14 are connected via a network or I / O connection, it is possible to turn the power supply unit (PSU) 12 on / off using the explosion-proof circuit (EPC) 60. The off / on function will be explained later.

[0057] (Second Isolation Circuit) Power is supplied to the Power Supply Unit (MPSU) 24, for example, via line LAC. Line LAC is a line that connects the power supply and the Power Supply Unit (MPSU) 24. In the example shown in Figure 1, power is supplied from the AC power supply 10 to the Power Supply Unit (MPSU) 24 via line LAC. Line LAC connects the AC power supply 10 and the Power Supply Unit (MPSU) 24. Specifically, the end of line LAC on the AC power supply 10 side is connected to lines L67 and L68. However, the end of line LAC on the AC power supply 10 side may be connected to lines L11 and L12, for example.

[0058] Line LAC is provided with a second isolation circuit (ICP) 32. The second isolation circuit (ICP) 32 is a circuit that isolates the motor drive circuit (MDC) 20 from the motor drive power supply. In the example shown in Figure 1, the second isolation circuit (ICP) 32 functions as a circuit that isolates the AC power supply 10 from the motor drive circuit (MDC) 20. The second isolation circuit (ICP) 32 is connected to the explosion-proof circuit (EPC) 60 via line L64. The disconnection or connection of the second isolation circuit (ICP) 32 is controlled by the explosion-proof circuit (EPC) 60.

[0059] (Control Unit) The control unit (CU) 14 is connected to the display / operation unit (DCU) 16 and the motor drive circuit (MDC) 20. The control unit (CU) 14 also receives power from the power supply PC. Furthermore, the control unit (CU) 14 is connected to the explosion-proof circuit (EPC) 60. In the explosion-proof system 1 of this embodiment, the control unit (CU) 14 and the explosion-proof circuit (EPC) 60 are connected via a network connection NC. In the conventional explosion-proof system 101, as shown in Figure 2, the control unit (CU) 14 and the explosion-proof circuit (EPC) 60 are connected via line L69. The network connection NC will be explained later.

[0060] The control unit (CU) 14 is primarily responsible for controlling the motor drive circuit (MDC) 20. The control unit (CU) 14 is connected to the motor drive circuit (MDC) 20 via a communication line LC and a control signal line LCS.

[0061] Furthermore, the control unit (CU) 14 is connected to the display and operation unit (DCU) 16 via line L16.

[0062] The control unit (CU) 14 may, for example, control the motor drive circuit (MDC) 20 based on the content operated by the display and operation unit (DCU) 16.

[0063] (Display and Operation Unit) As described above, the control content of the control unit (CU) 14 can be input from the display and operation unit (DCU) 16. The display and operation unit (DCU) 16 can also display the input control content and the control status.

[0064] The display and operation unit (DCU) 16 is connected to the explosion-proof circuit (EPC) 60 via the control unit (CU) 14. Therefore, the display and operation unit (DCU) 16 can display the explosion-proof status of the explosion-proof system 1. Specifically, the display and operation unit (DCU) 16 can display the detection results of the internal pressure sensor (IPS) 72, the detection results of the flow sensor (FVS) 74, and the status of the establishment of internal pressure explosion-proofing for the painting robot housing (PRH) 40.

[0065] Furthermore, in the explosion-proof system 1 of this embodiment, as described above, the control unit (CU) 14 and the explosion-proof circuit (EPC) 60 are connected via a network NC. Therefore, the display and operation unit (DCU) 16 can acquire and display purge information, such as the purge of the painting robot housing (PRH) 40 before the purging is completed, from the explosion-proof circuit. In addition, the explosion-proof circuit (EPC) 60 can control the supply of protective gas to the painting robot housing (PRH) 40 in response to input from the display and operation unit (DCU) 16.

[0066] The display and operation unit (DCU) 16 receives power from the power supply unit (PSU) 12. Even when the motor drive circuit (MDC) 20 and motor unit (MU) 42 are not energized, such as before the internal pressure explosion protection of the painting robot housing (PRH) 40 is established, the display and operation unit (DCU) 16 can display the status of the internal pressure sensor (IPS) 72 and the flow sensor (FVS) 74, and input operations.

[0067] (First Isolation Circuit) The first isolation circuit (ICC) 31 is provided in the communication line LC, the control signal line LCS, and the control power line PC that connect the control unit (CU) 14 and the motor drive circuit (MDC) 20. The first isolation circuit (ICC) 31 is a circuit that isolates the connection between the control unit (CU) 14 and the motor drive circuit (MDC) 20.

[0068] In the explosion-proof system 1 of this embodiment, only one first isolation circuit (ICC) 31 is provided. Unlike the conventional explosion-proof system 101 shown in Figure 2, when the first isolation circuit (ICC) 31 is provided on the input side from the control unit (CU) 14 to the motor drive circuit (MDC) 20, the lines that need to be isolated are only one set of communication lines LC, a control signal line, and a control power supply line.

[0069] In other words, in the explosion-proof system 1 of this embodiment, the electrical energy to the hazardous area HR, which is necessary when the painting robot housing (PRH) 40 does not meet the conditions for internal pressure explosion protection, is cut off on the upstream side of the motor drive circuit (MDC) 20. As a result, the number of first isolation circuits (ICCs) 31 can be reduced. This is because, as in the conventional explosion-proof system 101, it is not necessary to provide a first isolation circuit (ICC) for each communication line LM of each motor M.

[0070] The first isolation circuit (ICC) 31 is connected to the explosion-proof circuit (EPC) 60 via line L65. The disconnection or connection of the first isolation circuit (ICC) 31 is controlled by the explosion-proof circuit (EPC) 60.

[0071] This section will describe the establishment of the explosion-proof structure in the explosion-proof system 1 of this embodiment, and the commissioning of the explosion-proof system 1.

[0072] (Establishment of internal pressure explosion protection) First, we will establish internal pressure explosion protection for the painting robot enclosure (PRH) 40 located in the hazardous area HR.

[0073] Both the power supply unit (PSU) 12 and the explosion-proof circuit power supply (EPS) 62 are turned on. The explosion-proof circuit power supply (EPS) 62 remains on continuously without being turned off during the period when the explosion-proof system 1 is on.

[0074] Both the first isolation circuit (ICC) 31 and the second isolation circuit (ICP) 32 are disconnected. This establishes intrinsic safety.

[0075] The control unit (CU) 14 is supplied with power from the power supply unit (PSU) 12. The control unit (CU) 14 is in the ON state. Normally, it takes time for the control unit (CU) 14 to start up. In the explosion-proof system 1 of this embodiment, power is supplied to the control unit (CU) 14 before internal pressure explosion protection is established. Therefore, after internal pressure explosion protection is established, there is no need to wait until the control unit (CU) 14 starts up before starting to use the explosion-proof system 1.

[0076] The explosion-proof circuit (EPC) 60 is supplied with power from the explosion-proof circuit power supply (EPS) 62.

[0077] The explosion-proof circuit (EPC) 60 controls various parts to supply protective gases such as air or nitrogen to the painting robot housing (PRH) 40 in order to establish internal pressure explosion protection for the painting robot housing (PRH) 40. At the same time, the explosion-proof circuit (EPC) 60 may monitor the detection results of the internal pressure sensor (IPS) 72 and the flow sensor (FVS) 74, and may also control various parts by referring to the detection results. The explosion-proof circuit (EPC) 60 may also display information regarding the establishment of internal pressure explosion protection on the display and operation unit (DCU) 16. Furthermore, the explosion-proof circuit (EPC) 60 may change the content of the control regarding the establishment of internal pressure explosion protection based on the content input from the display and operation unit (DCU) 16.

[0078] The explosion-proof circuit (EPC) 60 can determine whether or not the internal pressure explosion-proofing of the painting robot housing (PRH) 40 has been established based on the detection results of the internal pressure sensor (IPS) 72 and the flow sensor (FVS) 74.

[0079] When the explosion-proof circuit (EPC) 60 determines that the internal pressure explosion-proofing of the painting robot housing (PRH) 40 has been established, the explosion-proof circuit (EPC) 60 connects both the first isolation circuit (ICC) 31 and the second isolation circuit (ICP) 32. This ensures that the entire explosion-proof system 1 operates safely.

[0080] (Power supply unit off / on function) The off / on function of the power supply unit (PSU) 12 will now be described. In the explosion-proof system 1 of this embodiment, after the conditions for internal pressure explosion protection are met, the voltage supply from the power supply unit (PSU) 12 to the motor drive circuit (MDC) 20 and the control unit (CU) 14 is temporarily turned off. Then, with the first isolation circuit (ICC) 31 connected, the power supply unit (PSU) 12 is turned on to establish communication between the control unit (CU) 14 and the motor drive circuit (MDC) 20. This allows for smooth connection of the control unit (CU) 14 to the motor drive circuit (MDC) 20 when power is supplied to the control unit (CU) 14.

[0081] In the explosion-proof system of this disclosure, both motor power and control signals are isolated in the motor drive circuit, specifically in front of the servo amplifier in the control unit, in order to cut off the energy supply to the robot before the internal pressure is applied. In conventional configurations employing battery-powered motors, i.e., battery-powered position memory devices (PMDs), isolation between the servo amplifier and the motor is necessary for an intrinsically safe structure.

[0082] In contrast, in cases where a battery-less motor, or a battery-less position memory device (PMD), is used, as in this disclosure, isolation becomes possible before the servo amplifier. Generally, isolation before the servo amplifier reduces the number of disconnection points, thereby improving reliability and reducing costs.

[0083] Furthermore, in the explosion-proof system of this disclosure, power is supplied to the servo amplifier only after the internal pressure application to the paint robot housing (PRH) is complete, and necessary communication and settings are performed within the control unit. For this communication and settings, the relevant electrical equipment within the control unit is temporarily powered off and then powered on. Meanwhile, the explosion-proof system of this disclosure is equipped with an external circuit, i.e., an explosion-proof circuit (EPC), which is unaffected by and does not affect the purging state of the paint robot housing (PRH).

[0084] Normally, initialization and communication settings are performed sequentially after the power is turned on. Therefore, initiating communication at an arbitrary time would complicate the process. To avoid this, the power is turned off and on again after purging is complete, and then reconnection is performed.

[0085] However, even when turning the power off and on to establish this communication, the purging status of the painting robot housing (PRH) must be monitored. For this reason, the explosion-proof system of this disclosure is equipped with an explosion-proof circuit power supply (EPS), which is an independent power supply, and an explosion-proof circuit (EPC), which is an external circuit connected to this independent power supply.

[0086] Furthermore, in the explosion-proof system of this disclosure, the control unit and external circuits communicate via a network before the power is turned off and on as described above, and until the purging of the paint robot housing (PRH) is complete. This allows monitoring of the purging status via the control unit. As a result, the purging status can be monitored. In addition, if purging fails, various switches can be turned off and on as needed, and feedback from the switches, such as the pressure and / or flow rate inside the paint robot housing (PRH), can be confirmed. This facilitates troubleshooting of purging failures.

[0087] This disclosure is not limited to the embodiments or modifications described above, and any modifications or improvements that can achieve the objectives of this disclosure are included.

[0088] An example of modification is shown in Figure 3. Figure 3 shows an explosion-proof system 1 of another embodiment of the present disclosure. Hereinafter, the explosion-proof system 1 shown in Figure 3 will be described, focusing on the differences from the explosion-proof system 1 shown in Figure 1. Matters of the explosion-proof system 1 shown in Figure 3 that are not specifically described can be the same as those of the explosion-proof system 1 shown in Figure 1.

[0089] The explosion-proof system 1 shown in Figure 3 differs from the explosion-proof system 1 shown in Figure 1 in that the part included inside the internal pressure explosion-proof structure is different. In the explosion-proof system 1 shown in Figure 1, the motor drive circuit (MDC) 20 was not included inside the internal pressure explosion-proof structure, as indicated by the boundary line L10. In contrast, in the explosion-proof system 1 shown in Figure 3, the motor drive circuit (MDC) 20 is included inside the internal pressure explosion-proof structure, as indicated by the boundary line L10.

[0090] For the control and driving of the motor unit (MU) 42, a control unit (CU) 14 and a power supply circuit are provided outside the internal pressure explosion-proof structure. The power supply circuit is a circuit for supplying power to the motor drive circuit (MDC) 20. The power supply circuit includes an AC power supply 10 and a line LAC, etc.

[0091] A circuit that electrically isolates the control unit (CU) 14 from the motor drive circuit (MDC) 20 is provided on the input side of the control signal to the motor drive circuit (MDC) 20. The first isolation circuit (ICC) 31 is the circuit that isolates the control unit (CU) 14.

[0092] Furthermore, a circuit that supplies power to the motor drive circuit (MDC) 20, that is, a circuit that electrically isolates the aforementioned power supply circuit from the motor drive circuit (MDC) 20, is provided on the power supply side to the motor drive circuit (MDC) 20. The second isolation circuit (ICP) 32 is a circuit that isolates the motor drive power supply circuit.

[0093] Thus, in the explosion-proof system 1 of this disclosure, even when the motor drive circuit (MDC) 20 is included inside the internal pressure explosion-proof structure, a highly reliable explosion-proof system 1 can be realized while suppressing manufacturing costs.

[0094] 1 Explosion-proof system 10 AC power supply 12 Power supply unit (PSU) 14 Control unit (CU) 16 Display and operation unit (DCU) 20 Motor drive circuit (MDC) 22 Motor drive circuit side position information communication unit (PCD) 24 Power supply unit (MPSU) 31 First isolation circuit (ICC) 32 Second isolation circuit (ICP) 40 Painting robot housing (PRH) 42 Motor unit (MU) 44 Position information communication unit (PCM) 46 Power drive unit (PDU) 51 Inlet 52 Scavenging port 54 Position detection circuit (PDC) 56 Position memory device (PMD) 60 Explosion-proof circuit (EPC) 62 Explosion-proof circuit power supply (EPS) 72 Internal pressure sensor (IPS) 74 Flow sensor (FVS)

Claims

1. An explosion-proof system comprising a motor unit inside an internal pressure explosion-proof structure, wherein the system includes a motor drive circuit electrically connected to the outside of the internal pressure explosion-proof structure for at least one of controlling and driving the motor unit, and has a circuit for electrically isolating the motor drive circuit on the input side of the control signal to the motor drive circuit and on the power supply side to the motor drive circuit.

2. The explosion-proof system according to claim 1, comprising: a control unit for controlling the motor drive circuit; a power supply unit for supplying power to the motor drive circuit and the control unit, respectively; an explosion-proof circuit for internal pressure explosion prevention; and a power supply for the explosion-proof circuit independent of the power supply unit, wherein, for the period until the internal pressure explosion-proof conditions of the internal pressure explosion-proof structure are met, at least the control unit is operated with the motor drive circuit isolated; and after the internal pressure explosion-proof conditions of the internal pressure explosion-proof structure are met, the power supply unit turns the motor drive circuit and the control unit on and off.

3. The explosion-proof system according to claim 2, wherein the control unit and the explosion-proof circuit are connected by a network.

4. An explosion-proof system comprising a motor section and a motor drive circuit inside an internal pressure explosion-proof structure, wherein the system includes a control unit and a power supply circuit to the motor drive circuit, which are electrically connected to the outside of the internal pressure explosion-proof structure for controlling and driving the motor section, and a circuit for electrically insulating the control unit and the power supply circuit to the motor drive circuit is provided on the input side of the control signal to the motor drive circuit and on the power supply side to the motor drive circuit.

Images