JP7789608B2 - controller - Google Patents

Description

The present invention relates to a controller with a metal housing.

Patent document 1 describes a robot controller that houses various units, such as a control circuit board, a drive circuit board, a communication interface board, a drive voltage generation board, and a power supply circuit board, inside a metal housing.

The controller in Patent Document 1 has an external power connector and a circuit protector on the front panel of the housing that switches between supplying and cutting off the 200V AC current input from the external power connector. Inside the housing are power supply system units such as a drive voltage generation board and a power circuit board equipped with a noise filter that removes noise from the AC current and a DC-AC conversion circuit that converts the noise-removed AC current into DC.

Patent No. 5803213

To suppress noise carried on the AC current supplied from an external power source, controllers use a structure that uses a metal case as a frame ground to allow noise to escape. For example, a frame ground terminal block is provided on the case by fastening a metal terminal block component with screws to a metal plate fixed to the case frame. Each unit in the power supply system is connected to the frame ground via a frame ground wire that runs between the unit and the frame ground terminal block.

However, when installing a frame ground terminal block on a housing, noise resistance may be insufficient depending on the configuration of the frame ground terminal block. For example, if the contact resistance between the terminal block components and the metal panel on the housing side is high, noise and surges cannot be completely dissipated.

In light of the above problems, the objective of this invention is to improve the noise resistance performance of controllers.

To solve the above problem, the controller of the present invention comprises a metal housing, a power input unit that receives AC current from an external power source, a DC/AC conversion circuit that converts the AC current supplied from the power input unit into DC current, and a drive current generation unit that generates a drive current to be output externally based on the DC current supplied from the DC/AC conversion circuit; the power input unit comprises a power input terminal block disposed within the housing and at least one noise filter to which AC current is input via the power input terminal block; the housing comprises a main frame on which the power input unit is mounted and a frame ground terminal block to which a protective earth wire of the power input unit is connected; the frame ground terminal block and the main frame are made of the same metal and are welded together with their base surfaces, which do not have a plating coating, in contact with each other.

According to the present invention, a frame ground terminal block made of the same metal as the mainframe is welded to the mainframe, which is a metal component that constitutes a controller housing and has a large capacity. The welding is performed with the base surfaces, which are not coated with plating, in contact with each other. By directly fastening the frame ground terminal block to the mainframe in this manner, ground resistance can be reduced compared to when other components are interposed between the mainframe and the frame ground terminal block. Furthermore, by abutting the base surfaces, which are not coated with plating, the contact resistance between the mainframe and the frame ground terminal block can be reduced. Reducing ground resistance facilitates noise escape from the frame ground terminal block, thereby improving noise resistance. Furthermore, fastening by welding ensures reliable contact, eliminating variations in contact resistance due to variations in screw tightening torque when fastening with screws. Therefore, variations in noise resistance performance can be suppressed. This allows the noise filter to be simplified while still achieving the required noise resistance performance, thereby reducing noise filter costs. Furthermore, reducing the number of screw fastening holes allows for the frame ground terminal block to be smaller, reducing component costs, and eliminating the risk of incorrect disassembly.

In the present invention, it is preferable that the main frame has a power input unit installation surface on which the power input unit is installed, and that the frame ground terminal block is arranged on the power input unit installation surface. In this way, the power input unit and the frame ground terminal block are arranged on the same surface. This improves the ease of routing and connecting the frame ground wire of the power input unit to the frame ground terminal block.

In the present invention, the main frame preferably includes a bottom plate of the housing and a frame-shaped housing frame connected to the outer edge of the bottom plate, the power input unit installation surface being provided on the bottom plate, and the frame ground terminal block being located on the outer edge of the bottom plate. This allows easy access to the frame ground terminal block by removing the outer panel fixed to the housing frame. This improves the ease of connecting a protective earth wire to the frame ground terminal block.

In the present invention, the frame ground terminal block preferably includes a fixed plate that abuts against the bottom plate and an inclined plate that extends along the outer edge of the bottom plate, the protective earth wire being fixed to the inclined plate, and the inclined plate inclining away from the bottom plate as it approaches the power input section from the outer edge. In this way, when the frame ground terminal block placed on the bottom plate is viewed diagonally from above, the fixing surface (i.e., the inclined plate) that fixes the protective earth wire can be seen. This improves the ease of connecting the protective earth wire.

In the present invention, the power input terminal block is preferably located at the tip of the power input section on the frame ground terminal block side. This allows the power input terminal block and the frame ground terminal block to be closer together. This makes it easier to connect the protective earth wire of the power input terminal block to the frame ground terminal block. Furthermore, since the power input terminal block and the frame ground terminal block can be located together at the tip of the power input section, wiring work can be done efficiently.

In the present invention, the power supply cable drawn into the housing preferably includes a power supply line that supplies AC current from an AC power source and an earth wire that is connected to the ground terminal of the AC power source, with the power supply line being connected to the power input terminal block and the earth wire being connected to the frame ground terminal block. In this way, by connecting the AC power source's earth wire directly to the frame ground terminal block, the frame ground can be effectively earthed. Therefore, by concentrating the protective earth wire of the power input section at the frame ground terminal block, the power input section can be effectively earthed via the frame ground terminal block.

In the present invention, the power input unit preferably includes a molded case circuit breaker disposed in the current supply path connecting the power input terminal block and the noise filter, and the protective earth wire of the power input terminal block and the protective earth wire of the noise filter are connected to the frame ground terminal block. In this way, many of the protective earth wires of the power input unit are concentrated at the frame ground terminal block. Therefore, by connecting the AC power supply's earth wire to the frame ground terminal block, many of the electronic elements that make up the power input unit are earthed via the frame ground terminal block, thereby improving noise resistance. It is also possible to simplify the noise filter and reduce costs.

In this case, the power input unit preferably includes a surge protector placed in the current supply path connecting the power input terminal block and the noise filter, and the protective earth wire of the surge protector is connected directly to the frame ground terminal block or to the frame ground terminal block via the power input terminal block. In this way, when a surge protector is added, the surge protector is also grounded via the frame ground terminal block, just like other electronic elements. This improves noise resistance.

In the present invention, the power input unit preferably includes a distribution connector that distributes the AC current that has passed through the noise filter, and the frame ground terminal block is connected to the protective earth wire of the power input terminal block, the protective earth wire of the noise filter, and the protective earth wire of the distribution connector. This reduces noise in the AC current supplied from the distribution connector, further improving noise resistance.

In the present invention, the power input unit comprises a first power input unit that supplies an AC current to generate a drive current, and a second power input unit that supplies an AC current to generate a control current of a voltage different from the drive current; the first power input unit comprises a first circuit breaker and at least one of the noise filters; the second power input unit comprises a second circuit breaker and at least one of the noise filters and a distribution connector; and the frame ground terminal block is connected to the protective earth wire of the power input terminal block, the protective earth wires of each noise filter provided in the first power input unit, the protective earth wires of each noise filter provided in the second power input unit, and the protective earth wire of the distribution connector; and it is preferable that the protective earth wire of the first surge protector and the protective earth wire of the second surge protector are connected directly to the frame ground terminal block or to the frame ground terminal block via the power input terminal block. In this way, the electronic elements that make up the first power supply input section and the electronic elements that make up the second power supply input section are each grounded via the frame ground terminal block, thereby reducing noise in the control current and drive current.

According to the present invention, a frame ground terminal block made of the same metal as the mainframe is welded to the mainframe, which is the largest metal component constituting the controller housing. The welding is performed with the base surfaces, which are not coated with plating, in contact with each other. By directly fastening the frame ground terminal block to the mainframe in this manner, ground resistance can be reduced compared to when other components are interposed between the mainframe and the frame ground terminal block. Furthermore, by abutting the base surfaces, which are not coated with plating, the contact resistance between the mainframe and the frame ground terminal block can be reduced. Reducing ground resistance facilitates noise escape from the frame ground terminal block, thereby improving noise resistance. Furthermore, fastening by welding ensures reliable contact, eliminating variations in contact resistance due to variations in screw tightening torque when fastening with screws. Therefore, variations in noise resistance performance can be suppressed. This allows the noise filter to be simplified while still achieving the required noise resistance performance, thereby reducing noise filter costs. Furthermore, reducing the number of screw fastening holes allows for a smaller frame ground terminal block, reducing component costs, and eliminating the risk of mis-disassembly of the frame ground terminal block.

1 is a perspective view of the appearance of a controller to which the present invention is applied; FIG. 2 is a partial perspective view of the controller with the interface panel and side panels removed. 2A and 2B are cross-sectional views of the controller (cross-sectional views taken along the line AA in FIG. 1) and partially enlarged views thereof. FIG. 2 is a block diagram schematically illustrating a power supply input unit. FIG. 2 is an enlarged perspective view of the main frame and the power input unit as viewed from the front side. FIG. 2 is a perspective view of a portion of the main frame to which a frame ground terminal block is fixed. 1A and 1B are perspective views of a frame ground terminal block as viewed obliquely from above and below. 10A and 10B are noise waveform diagrams of a noise terminal voltage test in the controller of the present embodiment and a conventional controller. FIG. 10 is a perspective view showing a connection mode of a protective earth wire when a frame terminal block of a modified example is used.

An embodiment of a controller to which the present invention is applied will be described below with reference to the drawings. The controller 1 of this embodiment is a device that supplies power to a robot (manipulator) equipped with an actuator such as a motor.

Figure 1 is an external perspective view of a controller 1 to which the present invention is applied. Figure 2 is a partial perspective view of the controller 1 with the interface panel 21A and side panel 24 removed. Figure 3 is a cross-sectional view of the controller 1 (a cross-sectional view taken at position A-A in Figure 1) and an enlarged view of a portion thereof.

In this specification, the three directions X, Y, and Z are mutually orthogonal. For convenience, in this specification, the Z direction is defined as the up-down direction of the controller 1. The Z1 direction is downward, and the Z2 direction is upward. The X direction is the front-to-back direction of the controller 1. The X1 direction is forward, and the X2 direction is backward. The Y direction is the width direction of the controller 1. The Y1 direction and the Y2 direction are one side and the other of the Y direction. Note that, in actual use of the controller 1, the Z direction does not have to coincide with the up-down direction (vertical direction).

(Overall structure)
1 to 3, the controller 1 includes a metal housing 2. The housing 2 is a rectangular parallelepiped, and includes a front surface 2a facing the X1 direction, a back surface 2b facing the X2 direction, a side surface 2c facing the Y1 direction, a side surface 2d facing the Y2 direction, a bottom surface 2e facing the Z1 direction, and a top surface 2f facing the Z2 direction. In this embodiment, the components that make up the housing 2 include three interface panels 21A, 21B, and 21C arranged on the front surface 2a, a back plate 22 arranged on the back surface 2b, a side plate 23 arranged on the side surface 2c on the Y1 side, a side plate 24 arranged on the side surface 2d on the Y2 side, a top plate 25 arranged on the top surface 2f, and a main frame 20.

The main frame 20 is a member formed integrally with a bottom plate 26 disposed on the bottom surface 2e and a rectangular parallelepiped housing frame 27 connected to the outer edge of the bottom plate 26. The interface panels 21A, 21B, and 21C, the back plate 22, the side plates 23 and 24, and the top plate 25 are outer panels of the housing 2, and are detachably fixed to the housing frame 27.

As shown in FIG. 2, the housing frame 27 comprises a rectangular front frame 27A, side frames 27B, and top frame 27C. Interface panels 21A, 21B, and 21B are fixed to the front frame 27A. A top plate 25 is fixed to the top frame 27C. A side plate 24 on the Y2 side is fixed to the side frame 27B. The front frame 27A and side frames 27B rise in the Z2 direction from the outer edge of the bottom plate 26 and connect to the outer edge of the top frame 27C. The housing frame 27 also comprises a back frame to which the back plate 22 is fixed, and a side frame to which the side plate 23 on the Y1 side is fixed (neither is shown).

The controller 1 is equipped with a power supply input unit 3 to which AC current is input from an external power supply. As shown in Figures 2 and 3, the power supply input unit 3 is located inside the interface panel 21A, which is located at the Y2 end of the front of the housing, in the internal space of the housing 2. As shown in Figures 1 and 3, two power supply cables 40 of the external AC power supply are pulled into the housing 2 from sleeves 28 attached to the interface panel 21A.

The controller 1 includes a DC/AC conversion circuit (not shown) that converts a portion of the AC current supplied from the power supply input unit 3 into DC current of a predetermined voltage, and a drive current generation unit (not shown) that generates a drive current to be output externally based on the DC current supplied from the DC/AC conversion circuit. The circuit boards and electronic elements that make up the DC/AC conversion circuit and drive current generation unit are located inside the housing 2. The drive current generation unit is connected to an external output connector 29 (see Figure 1) provided on the interface panel 21C. When the manipulator-side connector is connected to the external output connector 29, the drive current is supplied to the manipulator.

The controller 1 also includes a communication board (not shown), a control circuit board (not shown), and a cooling fan 6, all of which are located within the housing 2. Multiple external connection connectors 30, located at the end of the communication board, are placed in holes provided in the interface panel 21B. Multiple fans 6 are located inside the back panel 22. As shown in FIG. 2, one of the multiple fans 6 is located behind the power input unit 3 (on the X2 side).

(Power input section)
Fig. 4 is a block diagram schematically showing the power input unit 3. Fig. 5 is a perspective view of the main frame 20 and the power input unit 3 as viewed from the front side (X1 side). As shown in Fig. 4, the power input unit 3 includes a power input terminal block 4, and a first power input unit 5A and a second power input unit 5B to which AC current is supplied via the power input terminal block 4.

As shown in FIG. 4, one of the two power supply cables 40 drawn into the housing 2 has three power supply lines 40A for supplying three-phase AC current for the drive power supply and one earth wire GL1 connected to the ground terminal of the external AC power supply. The second power supply cable 40 has two power supply lines 40B for supplying two-phase AC current for the control power supply and one earth wire GL2 connected to the ground terminal of the external AC power supply. The three power supply lines 40A and two power supply lines 40B are connected to the power supply input terminal block 4. As will be described later, the earth wires GL1 and GL2 are connected to the frame ground terminal block 10 (see FIG. 5) rather than to the power supply input terminal block 4.

The 200 V AC current input to the power supply input unit 3 is supplied to the first power supply input unit 5A and the second power supply input unit 5B via the power supply input terminal block 4. Three-phase AC current, which serves as the drive power supply, is input to the first power supply input unit 5A via the power supply line 40A and the power supply input terminal block 4. Two-phase AC current, which serves as the control power supply, is input to the second power supply input unit 5B via the power supply line 40B and the power supply input terminal block 4.

As shown in FIG. 4, the first power supply input section 5A includes a first wiring circuit breaker 51, a first surge protector 52, a first noise filter 53, and a second noise filter 54. The first noise filter 53 and the second noise filter 54 include filter circuits for removing noise superimposed on the AC current supplied to the first power supply input section 5A. The first wiring circuit breaker 51 is a no-fuse breaker. The first wiring circuit breaker 51 and the first surge protector 52 are arranged in the current supply path connecting the power supply input terminal block 4 and the first noise filter 53.

The second power supply input section 5B includes a second wiring circuit breaker 55, a second surge protector 56, a third noise filter 57, and a distribution connector 58. The third noise filter 57 includes a filter circuit for removing noise superimposed on the AC current supplied to the second power supply input section 5B. The second wiring circuit breaker 55 is a circuit protector. The second wiring circuit breaker 55 and the second surge protector 56 are arranged in the current supply path connecting the power supply input terminal block 4 and the third noise filter 57.

The distribution connector 58 distributes the AC current output from the second noise filter 54 to multiple destinations. The AC current distributed from the distribution connector 58 is converted into a control current with a different voltage than the drive current. For example, the AC current distributed from the distribution connector 58 generates a 24V DC current supplied to the fan 6 and a 5V DC current supplied to the control circuit board.

The power input unit 3 is a unit that is elongated in the X direction overall. As shown in Figures 2 and 4, the power input terminal block 4 is located at the front end (X1 end) of the power input unit 3. The first and second circuit breakers 51 and 55 are located side by side above the power input terminal block 4 (Z2 side) at the front end (X1 end) of the power input unit 3. As shown in Figure 3, the first surge protector 52 is located behind the first circuit breaker 51 (X2 side). As shown in Figure 2, the second surge protector 56 is located behind the second circuit breaker 55 (X2 side). The front ends of the first and second circuit breakers 51 and 55 protrude forward (in the X1 direction) beyond the power input terminal block 4 and are located in the opening 31 of the interface panel 21A (see Figure 1). The power input terminal block 4 is located inside the interface panel 21A.

As shown in FIG. 3, the first noise filter 53 and the second noise filter 54 are arranged in the front-to-rear direction (X direction) behind the Y1 side (X2 side) of the power input terminal block 4. The first noise filter 53 is located behind (X2 side) the power input terminal block 4, and the second noise filter 54 is located behind (X2 side) the first noise filter 53.

As shown in Figure 2, the third noise filter 57 and distribution connector 58 are arranged in the front-to-rear direction (X direction) behind the Y2 side (X2 side) of the power input terminal block 4. The third noise filter 57 is located behind (X2 side) the power input terminal block 4, and the distribution connector 58 is located behind (X2 side) the third noise filter 57. As shown by the dashed line in Figure 3, the third noise filter 57 is located in a position aligned with the first noise filter 53 in the Y direction. The distribution connector 58 is located in a position aligned with the rear end of the second noise filter 54 in the Y direction.

The power input unit 3 is formed as a unit by screwing the power input terminal block 4, the electronic elements constituting the first power input unit 5A, and the electronic elements constituting the second power input unit 5B to a metal base plate 60. The main frame 20 has a power input unit mounting surface 32 on which the power input unit 3 is mounted. The power input unit 3 is fixed to the main frame 20 by screwing the base plate 60 to the power input unit mounting surface 32. Therefore, as shown in FIGS. 2 and 3 , the power input unit mounting surface 32 is provided on the bottom plate 26.

The base plate 60 includes a first plate portion 61 parallel to the bottom plate 26 and a second plate portion 62 bent in the Z2 direction from the X1-side end of the first plate portion 61. As shown in Figures 2 and 3, the power input terminal block 4, first circuit breaker 51, first surge protector 52, second circuit breaker 55, and second surge protector 56 are fixed to the second plate portion 62. The power input terminal block 4, first circuit breaker 51, and second circuit breaker 55 are located on the X1 side of the second plate portion 62, while the first surge protector 52 and second surge protector 56 are located on the X2 side of the second plate portion 62. The first noise filter 53, second noise filter 54, third noise filter 57, and distribution connector 58 are fixed to the first plate portion 61.

(Frame ground terminal block)
In this embodiment, the protective earth wire PE1 of the power supply input terminal block 4, the protective earth wire PE2 of the first noise filter 53, the protective earth wire PE3 of the second noise filter 54, the protective earth wire PE4 of the third noise filter 57, the protective earth wire PE5 of the distribution connector 58, the protective earth wire PE6 of the first surge protector 52, and the protective earth wire PE7 of the second surge protector 56 are drawn out from the power supply input section 3 in the X1 direction.

The housing 2 is equipped with a frame ground terminal block 10 to which five of the seven protective earth wires (protective earth wires PE1 to PE5) of the power input unit 3 and the earth wires GL1 and GL2 of the power supply cable 40 are connected. As shown in Figures 2, 3, and 5, the frame ground terminal block 10 is located on the outer edge of the bottom plate 26 on the X1 side. Therefore, when the interface panel 21A is removed from the main frame 20, the frame ground terminal block 10 is located in a position that is easily accessible from the opening in the front frame 27A.

The frame ground terminal block 10 is located on the front side (X1 side) of the power input unit 3, and is positioned adjacent to the power input unit 3 in the front-to-back direction (X direction) on the power input unit installation surface 32. Therefore, the power input terminal block 4 and the frame ground terminal block 10, which are located at the X1 side end of the power input unit 3, are positioned adjacent to each other in the front-to-back direction (X direction).

The frame ground terminal block 10 is made of the same metal material as the main frame 20. In this embodiment, the frame ground terminal block 10 and the main frame 20 are made of SPCC (cold-rolled steel plate). The frame ground terminal block 10 is fixed to the main frame 20 by welding. The frame ground terminal block 10 and the main frame 20 are welded together before plating, and then plated after welding. Therefore, the frame ground terminal block 10 and the main frame 20 are welded together with their unplated base surfaces abutting against each other.

Figure 6 is a perspective view of the portion of the main frame 20 to which the frame ground terminal block 10 is fixed. Figure 7 is a perspective view of the frame ground terminal block 10 viewed from diagonally above and diagonally below. As shown in Figures 3, 6, and 7, the frame ground terminal block 10 includes a fixed plate 11 that abuts against the bottom plate 26, an inclined plate 13 with multiple screw holes 12, and a connecting plate 14 that connects the fixed plate 11 and the inclined plate 13. The fixed plate 11 extends in the Y direction. The fixed plate 11 abuts against the bottom plate 26 in an unplated state and is welded to the bottom plate 26. The connecting plate 14 includes a side plate 15 that bends at a substantially right angle from the X1-side end of the fixed plate 11 and rises in the Z2 direction, and a top plate 16 that bends at a substantially right angle from the X1-side end of the side plate 15 and extends in the X1 direction. The inclined plate 13 extends from the X1-side end of the top plate 16 toward the outer edge of the bottom plate 26.

The inclined plate 13 extends in the Y direction along the outer edge of the bottom plate 26 on the X1 side. The inclined plate 13 constitutes a ground wire fixing surface with multiple screw holes 12 for fixing the protective earth wires PE1 to PE5 and the ground wires GL1 and GL2. The inclined plate 13 is inclined at an angle of 45 degrees or close to 45 degrees relative to the bottom plate 26. More specifically, the inclined plate 13 inclines in a direction away from the bottom plate 26 (toward the Z2 side) as it extends from the outer edge of the bottom plate 26 toward the inside of the bottom plate 26 (toward the X2 side). In other words, when viewed from diagonally above with the interface panel 21A removed, the inclined plate 13 is angled so that the screw holes 12 are visible from the front, and is inclined in a direction that makes it easy to screw in the protective earth wires PE1 to PE5 and the ground wires GL1 and GL2.

The frame ground terminal block 10 has seven screw holes 12. Five of the seven protective earth wires (protective earth wires PE1 to PE5) and the earth wires GL1 and GL2 of the power supply cable 40 are fixed to the seven screw holes 12 arranged in a row on the inclined plate 13 using conductive metal screws (not shown). The protective earth wire PE6 of the first surge protector 52 and the protective earth wire PE7 of the second surge protector 56 are connected to the power input terminal block 4, and are then connected to the frame ground terminal block 10 via the power input terminal block 4 and the protective earth wire PE1.

As described above, the power input terminal block 4 is positioned adjacent to the frame ground terminal block 10, so the path for routing the protective earth wire PE1 of the power input terminal block 4 is short. Furthermore, the first surge protector 52 and the second surge protector 56 are fixed to the second plate portion 62 of the base plate 60 on the Z2 side of the power input terminal block 4, so the path for routing the frame ground wires FG6 and FG7 of the first surge protector 52 and the second surge protector 56 is short.

As shown in Figure 3, the first noise filter 53, second noise filter 54, third noise filter 57, and distribution connector 58 are located on the opposite side (X2 side) of the power input terminal block 4 from the frame ground terminal block 10. Therefore, the frame ground wires PE2 to PE5 can be pulled forward from the rear of the power input terminal block 4, passing along the side of the power input terminal block 4 (Y2 side), so the route for routing the protective earth wires PE6 and PE7 is simple and relatively short.

(Noise terminal voltage test)
8A and 8B are noise waveform diagrams of the controller of this embodiment and a conventional controller in a noise terminal voltage test. Fig. 8A is a noise waveform diagram of the controller of the conventional embodiment in a noise terminal voltage test, and Fig. 8B is a noise waveform diagram of the controller of this embodiment in a noise terminal voltage test. Unlike this embodiment, the conventional controller has a structure in which a plated frame ground terminal block is fixed with screws to a plated housing part.

The noise terminal voltage test is performed in a shielded room by placing a line impedance stabilization network between the controller 1 and the AC power supply, and measuring the noise output to the measurement terminals of the line impedance stabilization network with a spectrum analyzer. In the noise waveform diagrams of Figures 8(a) and 8(b), the horizontal axis represents frequency and the vertical axis represents noise level. The limit values (QP) and limit values (AV) shown in Figures 8(a) and 8(b) are values that comply with the common EMC standard (EN61000-6-4 Class A).

As can be seen from the noise waveform diagram in Figure 8(a), the conventional controller only has a 0.2 dB margin to the limit value at frequencies F1 and F2, so it is unable to completely eliminate noise. In contrast, as can be seen from the noise waveform diagram in Figure 8(b), the controller 1 of this embodiment has a 5 dB or greater margin to the limit value at frequencies F1 and F2, which is within the acceptable level. Therefore, by adopting the configuration of the frame ground terminal block 10 of this embodiment, noise resistance performance is improved compared to the conventional controller.

(Main effects of this embodiment)
As described above, the controller 1 of this embodiment includes a metal housing 2, a power supply input unit 3 to which AC current is input from an external power supply, a DC/AC conversion circuit that converts the AC current supplied from the power supply input unit 3 to DC current, and a drive current generation unit that generates a drive current to be output to the outside based on the DC current supplied from the DC/AC conversion circuit. The power supply input unit 3 includes a power supply input terminal block 4 disposed within the housing 2 and noise filters (first noise filter 53, second noise filter 54, third noise filter 57) to which AC current is input via the power supply input terminal block 4. The housing 2 includes a mainframe 20 on which the power supply input unit 3 is mounted and a frame ground terminal block 10 to which the protective earth wires PE1 to PE5 of the power supply input unit 3 are connected. The frame ground terminal block 10 and the mainframe 20 are made of the same metal and are welded together with their base surfaces, which are not coated with a plating film, in contact with each other.

In this embodiment, the frame ground terminal block 10 is fixed directly to the mainframe 20, which is a high-capacity metal component constituting the controller 1's housing 2. This reduces ground resistance compared to when other components are interposed between the mainframe 20 and the frame ground terminal block 10. Furthermore, because the base surfaces (not including the plated coating) are abutted and welded together, contact resistance between the mainframe 20 and the frame ground terminal block 10 is low. This facilitates noise escape from the frame ground terminal block 10, resulting in high noise resistance. Furthermore, because the frame ground terminal block 10 is fixed by welding, reliable contact is achieved, eliminating variations in contact resistance due to variations in screw tightening torque, and suppressing variations in noise resistance. This allows for a simplified noise filter while still achieving the required noise resistance, thereby reducing noise filter costs. Furthermore, eliminating screw fastening holes from the frame ground terminal block 10 allows for a more compact frame ground terminal block 10, reducing component costs, and eliminating the risk of accidental disassembly of the frame ground terminal block 10.

In this embodiment, the frame ground terminal block 10 is placed on the power input unit installation surface 32 of the main frame 20. By placing the power input unit 3 and the frame ground terminal block 10 on the same surface in this way, the frame ground terminal block 10 can be placed near the power input unit 3, which improves workability when routing and connecting the power supply unit's protective earth wires PE1 to PE5 to the frame ground terminal block 10.

In this embodiment, the main frame 20 includes a bottom plate 26 of the housing 2 and a frame-shaped housing frame 27 that connects to the outer edge of the bottom plate 26, making it the metal component that makes up the housing 2 with the largest capacity. Furthermore, a power input unit mounting surface 32 is provided on the bottom plate 26, and the frame ground terminal block 10 is positioned on the outer edge of the bottom plate 26. In this configuration, the frame ground terminal block 10 can be easily accessed by removing an outer panel (e.g., interface panel 21A) fixed to the housing frame 27. This facilitates easy connection of the protective earth wires PE1 to PE5 to the frame ground terminal block 10.

In this embodiment, the frame ground terminal block 10 includes a fixed plate 11 that abuts against the bottom plate 26, and an inclined plate 13 that extends along the outer edge of the bottom plate 26. The inclined plate 13 forms the frame ground wire fixing surface. The inclined plate 13 inclines away from the bottom plate 26 as it approaches the power input unit 3 from the outer edge. Therefore, when the frame ground terminal block 10 placed on the bottom plate 26 is viewed diagonally from above, the screw holes 12 in the inclined plate 13 are visible from the front, improving workability when connecting the protective earth wires PE1 to PE5.

In this embodiment, the power input terminal block 4 is located at the tip of the power input unit 3 on the frame ground terminal block 10 side (i.e., the X1 side), so the power input terminal block 4 and the frame ground terminal block 10 are close to each other. This makes it easy to connect the frame ground wire FG1 of the power input terminal block 4 to the frame ground terminal block 10. Furthermore, because the power input terminal block 4 and the frame ground terminal block 10 are located together on the tip side (X1 side) of the power input unit 3, wiring work can be done efficiently.

In this embodiment, the power supply cable 40 drawn into the housing 2 includes power supply lines 40A and 40B that supply AC current from the AC power supply and ground wires GL1 and GL2 that connect to the ground terminal of the AC power supply. Power supply lines 40A and 40B are connected to the power supply input terminal block 4, and ground wires GL1 and GL2 are connected to the frame ground terminal block 10. In this way, by connecting the AC power supply's ground wires GL1 and GL2 directly to the frame ground terminal block 10, the frame ground can be effectively earthed. Therefore, by concentrating the protective earth wires PE1 to PE5 of the power supply input unit 3 at the frame ground terminal block 10, the power supply input unit 3 can be effectively earthed via the frame ground terminal block 10.

In this embodiment, the power input unit 3 includes circuit breakers (first circuit breaker 51, second circuit breaker 55) and surge protectors (first surge protector 52, second surge protector 56) arranged in the current supply path connecting the power input terminal block 4 and the noise filters (first noise filter 53, third noise filter 57). The frame ground terminal block 10 is connected to the protective earth wire PE1 of the power input terminal block 4 and the protective earth wires PE2, PE3, and PE4 of the noise filters (first noise filter 53, second noise filter 54, third noise filter 57). Meanwhile, the protective earth wire PE6 of the first surge protector 52 and the protective earth wire PE7 of the second surge protector 56 are connected to the power input terminal block 4 and are then connected to the frame ground terminal block 10 via the power input terminal block 4 and the protective earth wire PE1.

In this way, in this embodiment, many of the protective earth wires of the power input unit 3 are concentrated at the frame ground terminal block 10. Therefore, by connecting the AC power supply's earth wires GL1 and GL2 to the frame ground terminal block 10, many of the electronic elements that make up the power input unit 3 are earthed via the frame ground terminal block 10, resulting in high noise resistance. Therefore, the required noise resistance can be obtained even with a simplified noise filter, allowing for cost reductions in the noise filter.

In this embodiment, the power input unit 3 is equipped with a distribution connector 58 that distributes the AC current that has passed through the third noise filter 57. The frame ground terminal block 10 is connected to the protective earth wire PE1 of the power input terminal block 4, the protective earth wire PE4 of the third noise filter 57, and the protective earth wire PE5 of the distribution connector 58. This reduces the noise in the AC current supplied from the distribution connector 58, further improving noise resistance.

In this embodiment, the power supply input unit 3 includes a first power supply input unit 5A that supplies an AC current for generating a drive current, and a second power supply input unit 5B that supplies an AC current for generating a control current with a voltage different from that of the drive current. The first power supply input unit 5A includes a first wiring circuit breaker 51, a first surge protector 52, a first noise filter 53, and a second noise filter 54. The second power supply input unit 5B includes a second wiring circuit breaker 55, a second surge protector 56, a third noise filter 57, and a distribution connector 58. The frame ground terminal block 10 is connected to a protective earth wire PE1 of the power supply input terminal block 4, and protective earth wires P2 of the first noise filter 53 and the second noise filter 54 provided in the first power supply input unit 5A.
E2 and PE3 are connected to each other, and also the protective earth wire PE4 of the third noise filter 57 provided in the second power supply input section 5B and the protective earth wire PE5 of the distribution connector 58 are connected to each other. Furthermore, the protective earth wire PE6 of the first surge protector 52 and the protective earth wire PE7 of the second surge protector 56 are connected to the power supply input terminal block 4 as described above, and are connected to the frame ground terminal block 10 via the power supply input terminal block 4 and the protective earth wire PE1. Therefore, the electronic elements that make up the first power supply input section 5A and the electronic elements that make up the second power supply input section 5B are each grounded via the frame ground terminal block 10, thereby reducing noise in the control current and drive current.

The configuration of the electronic elements that make up the first power input section 5A and the second power input section 5B is not limited to the above configuration and can be modified as appropriate. For example, in the above configuration, the first power input section 5A is equipped with two noise filters and the second power input section 5B is equipped with one noise filter, but the number of noise filters is not limited to the above configuration. Also, the first surge protector 52 and the second surge protector 56 can be omitted.

(Modification)
FIG. 9 is a perspective view showing the connection of protective earth wires PE1-PE7 when using a modified frame terminal block 10A. The frame terminal block 10A shown in FIG. 9 has nine screw holes 12. Therefore, in addition to the protective earth wires PE1-PE5, the protective earth wire PE6 of the first surge protector 52 and the protective earth wire PE7 of the second surge protector 56 are directly connected to the frame terminal block 10A. Therefore, all of the protective earth wires of the electronic elements that make up the power supply input unit 3 are directly connected to the frame terminal block 10A, further improving noise resistance. Furthermore, as with the above embodiment, the earth wires GL1 and GL2 are directly connected to the frame terminal block 10A, so each electronic element that makes up the power supply input unit 3 can be effectively earthed.

1...controller, 2...chassis, 2a...front, 2b...rear, 2c, 2d...side, 2e...bottom, 2f...top, 3...power input section, 4...power input terminal block, 5A...first power input section, 5B...second power input section, 6...fan, 10, 10A...frame ground terminal block, 11...fixing plate, 12...screw hole, 13...inclined plate, 14...connection plate, 15...side plate, 16...top plate, 20...main frame, 21A, 21B, 21C...interface panel, 22...rear plate, 23, 24...side plate, 25...top plate, 26...bottom plate, 27...chassis frame, 27A...front frame, 27B...side frame, 27C...top frame , 28...sleeve, 29...external output connector, 30...external connection connector, 31...opening, 32...power input unit installation surface, 40...power supply cable, 40A, 40B...power supply line, 51...first wiring circuit breaker, 52...first surge protector, 53...first noise filter, 54...second noise filter, 55...second wiring circuit breaker, 56...second surge protector, 57...third noise filter, 58...distribution connector, 60...base plate, 61...first plate portion, 62...second plate portion, GL1, GL2...earth wire, PE1, PE2, PE3, PE4, PE5, PE6, PE7...protective earth wire

Claims (10)

A metal housing and
a power supply input section to which AC current is input from an external power supply;
a DC/AC conversion circuit that converts AC current supplied from the power supply input unit into DC current, and a drive current generation unit that generates a drive current to be output to an external device based on the DC current supplied from the DC/AC conversion circuit,
the power supply input unit includes a power supply input terminal block disposed within the housing and at least one noise filter to which AC current is input via the power supply input terminal block;
the housing includes a main frame on which the power input unit is installed and a frame ground terminal block to which a protective earth wire of the power input unit is connected,
A controller characterized in that the frame ground terminal block and the main frame are made of the same metal and are welded together with their base surfaces, which are not coated with plating, in contact with each other. the main frame includes a power input unit installation surface on which the power input unit is installed,
2. The controller according to claim 1, wherein the frame ground terminal block is disposed on a surface on which the power input unit is installed. the main frame includes a bottom plate of the housing and a frame-shaped housing frame connected to an outer edge of the bottom plate,
the power input unit installation surface is provided on the bottom plate,
The controller according to claim 2 , wherein the frame ground terminal block is disposed on an outer edge of the bottom plate. the frame ground terminal block includes a fixed plate that contacts the bottom plate and an inclined plate that extends along the outer edge of the bottom plate, and the protective earth wire is fixed to the inclined plate;
The controller according to claim 3 , wherein the inclined plate is inclined in a direction away from the bottom plate as it approaches the power input portion from the outer edge. A controller as described in any one of claims 1 to 4, characterized in that the power input terminal block is located at the tip of the power input section on the frame ground terminal block side. the power supply cable drawn into the housing includes a power supply line for supplying AC current from an AC power supply and a ground line connected to a ground terminal of the AC power supply;
the power supply line is connected to the power input terminal block;
6. The controller according to claim 1, wherein the earth wire is connected to the frame ground terminal block. the power supply input unit includes a molded-case circuit breaker disposed in a current supply path connecting the power supply input terminal block and the noise filter,
7. The controller according to claim 1, wherein a protective earth wire of the power supply input terminal block and a protective earth wire of the noise filter are connected to the frame ground terminal block. the power supply input unit includes a surge protector disposed in a current supply path connecting the power supply input terminal block and the noise filter,
8. The controller according to claim 7, wherein the protective earth wire of the surge protector is connected directly to the frame ground terminal block or is connected to the frame ground terminal block via the power input terminal block. the power supply input unit includes a distribution connector that distributes the AC current that has passed through the noise filter;
A controller as claimed in any one of claims 1 to 8, characterized in that the frame ground terminal block is connected to a protective earth wire of the power supply input terminal block, a protective earth wire of the noise filter, and a protective earth wire of the distribution connector. the power supply input unit includes a first power supply input unit that supplies an AC current for generating a drive current, and a second power supply input unit that supplies an AC current for generating a control current having a voltage different from that of the drive current;
the first power supply input unit includes a first molded case circuit breaker, a first surge protector, and at least one of the noise filters;
the second power input section includes a second molded case circuit breaker, a second surge protector, and at least one of the noise filter and a distribution connector;
a protective earth wire of the power supply input terminal block, a protective earth wire of each noise filter provided in the first power supply input section, a protective earth wire of each noise filter provided in the second power supply input section, and a protective earth wire of the distribution connector are connected to the frame ground terminal block;
A controller as described in any one of claims 1 to 6, characterized in that the protective earth wire of the first surge protector and the protective earth wire of the second surge protector are connected directly to the frame ground terminal block or connected to the frame ground terminal block via the power input terminal block.