Robot control device and robot system

A robot control device that controls operation of a robot having an actuator includes a casing, an actuator driver, a drive-control board, a main control board, a main power supply board, a vent passage, a cooling fan, and a holding member. The actuator driver is accommodated in the casing and drives the actuator. The drive-control board is accommodated in the casing and controls operation of the actuator driver. The main control board is accommodated in the casing and controls operation of the drive-control board. The main power supply board is accommodated in the casing and supplies a power to the drive-control board and the main control board. The vent passage is defined by at least the drive-control board, the main control board, and the main power supply board and has an end open to the exterior of the casing. The cooling fan is arranged at an end of the vent passage and causes the air to flow through the vent passage. The holding member is provided in the vent passage and holds the actuator driver.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2005-344651, filed on Nov. 29, 2005 and Japanese Patent Application No. 2006-170736, filed on Jun. 20, 2006, the entire contents of which are incorporated herein by reference.

BACKGROUND

The present invention relates to a robot control device and a robot system.

Typically, an industrial robot system includes an industrial robot and a robot control device connected to the industrial robot through a power supply cable and a signal cable. As described in JP-A-11-188686 and JP-A-9-198120, the industrial robot receives a signal from the robot control device and operates in accordance with the signal.

To save space in a production facility, it is now desirable to reduce the size of the robot control device. However, since various heat sources including a servo amplifier are stored in a casing of the robot control device, the heat radiating surface area of the casing as a whole must be relatively great so as to cool the heat sources. Alternatively, a large-sized fan may be provided to forcibly cool the interior of the casing. The size of the casing of the robot control device thus becomes large, which makes miniaturization of the robot control device difficult. Further, the above-described two publications do not teach a cooling structure that operates in correspondence with the amount of the heat generated by the heat sources.

JP-A-6-216552 has proposed a technique that improves cooling efficiency of such electronic devices. Specifically, electronic element mounting surfaces of print circuit boards, each of which is arranged in the vicinity of a side surface of a casing, are oriented in such a manner as to face inward with respect to the casing. This orientation exposes the electronic elements in the vicinity of the side surfaces of the casing to the cooling air flowing at an increased flow rate. This enhances the cooling efficiency of the print circuit boards. Alternatively, as described in JP-A-2002-353679, a cooling duct having a vent hole is provided in the casing. A plurality of heat lanes extend from the cooling duct. A servo amplifier, a power supply, and a transformer are connected to the corresponding ones of the heat lanes. This arrangement permits transportation of a large amount of heat through the heat lanes, improving cooling efficiency of the heat generating bodies.

Nonetheless, in the technique of JP-A-6-216552, improvement of the cooling efficiency is not achieved in the entire portion of the interior of the casing but restricted to the vicinity of the side surfaces of the casing. In JP-A-2002-353679, the cooling duct, which is provided independently, enlarges the size of the casing, making it impossible to reduce the size of the robot control device.

SUMMARY

Accordingly, it is an objective of the present invention to provide a robot control device that improves cooling efficiency and has reduced size and a robot system including such robot control device.

In accordance with a first aspect of the present invention, a robot control device that controls operation of a robot having an actuator. The device includes a casing, an actuator driver that is accommodated in the casing and drives the actuator, a drive-control board that is accommodated in the casing and controls operation of the actuator driver, a main control board that is accommodated in the casing and controls operation of the drive-control board, a main power supply board that is accommodated in the casing and supplies a power to the drive-control board and the main control board, a vent passage defined by at least the drive-control board, the main control board, and the main power supply board, the vent passage having an end open to the exterior of the casing, a cooling fan that is arranged at an end of the vent passage and causes the air to flow through the vent passage, and a holding member that is provided in the vent passage and holds the actuator driver.

In accordance with a second aspect of the present invention, a robot control device that controls operation of a robot having an actuator is provided. The device includes an actuator driver that drives the actuator, a drive-control board that controls operation of the actuator driver, a main control board that controls operation of the drive-control board, a main power supply board that supplies a power to the drive-control board and the main control board, a casing that accommodates the actuator driver, the drive-control board, the main control board, and the main power supply board, the casing including four plates that are arranged in such a manner as to form a rectangular pipe, the drive-control board, the main control board, and the main power supply board being each secured to a corresponding one of three of the four plates, a vent passage defined by the drive-control board, the main control board, the main power supply board, and the remaining plate to which none of the boards is attached, the vent passage having an end open to the exterior of the casing, a cooling fan that is arranged at an end of the vent passage and causes the air to flow through the vent passage, and a holding member that is provided in the vent passage and holds the actuator driver.

In accordance with a third aspect of the present invention, a robot system including a robot having an actuator and a control device that controls operation of the robot is provided. The control device includes a casing, an actuator driver that is accommodated in the casing and drives the actuator, a drive-control board that is accommodated in the casing and controls operation of the actuator driver, a main control board that is accommodated in the casing and controls operation of the drive-control board, a main power supply board that is accommodated in the casing and supplies a power to the drive-control board and the main control board, a vent passage defined by at least the drive-control board, the main control board, and the main power supply board, the vent passage having an end open to the exterior of the casing, a cooling fan that is arranged at an end of the vent passage and causes the air to flow through the vent passage, and a holding member that is provided in the vent passage and holds the actuator driver.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

As shown inFIG. 1, a robot system includes a robot RB and a robot controller1as a robot control device. The robot RB is a horizontally articulated type four-axis control industrial robot. Operation of the robot RB is controlled by the robot controller1. A casing2of the robot controller1is a substantially parallelepiped box-like body. The casing2has a base portion3that extends in a left-and-right direction. A pair of interface connectors10,11are provided on a front surface3aof the base portion3.

A connector15of a connection cable13is connected to the interface connector10and a connector16of a connection cable14is connected to the interface connector11. The connection cable13and the connection cable14are connected to a personal computer PC and a teaching pendant TP, respectively. Information regarding setting of the robot RB, information regarding instructions of the robot RB, drive signals that instructs actuation of the robot RB, and peripheral drive signals that control peripheral functions such as a man-machine interface are input to the personal computer PC and the teaching pendant TP.

As shown inFIG. 2, the casing2includes a left side plate4, a right side plate5, a top plate6, a rear side plate, or a back plate7, and a front side plate, or an open-close panel8. The base portion3, the left side plate4, the right side plate5, the top plate6, and the back plate7form a box-like body having a front opening. The top side of the open-close panel8is connected to the top plate6through a hinge H. The open-close panel8pivots about the hinge H, the support point, thus selectively opening and closing the front side of the box-like body.

A vent hole W1is defined in the left side plate4and a vent hole W2is defined in the right side plate5. A fan filter FF is detachably attached to an outer side surface of the left side plate4in such a manner as to cover the vent hole W1. A pair of vertically stacked cooling fans F are secured to an inner side surface of the left side plate4through a hollow spacer T. The hollow spacer T ensures a suction distance for the cooling fans F. The cooling fans F each draw the external air from the veht hole W1to the interior of the casing2. The drawn air is then forcibly discharged from the vent hole W2. In other words, the external air is drawn from one of the opposing side surfaces of the casing2and flows through the casing2toward the other side surface (in direction Y ofFIG. 2).

A CPU board20, or a main control board, is secured to the upper surface of the base portion3, or the bottom plate, in the casing2. The CPU board20is formed as a flat plate that extends in directions X and Y. A surface of the CPU board20extends parallel with the air vent direction. This arrangement allows the CPU board20to decrease flow resistance in the air vent direction, thus enhancing cooling efficiency. A heat generating surface of the CPU board20, which is, for example, a mounting surface on which circuit elements are mounted, faces inward with respect to the casing2. The CPU board20is connected to the interface connectors10,11of the base portion3and receives various types of information and different types of signals from the personal computer PC and the teaching pendant TP. The CPU board20generates position instruction signals in accordance with the drive signals input from the personal computer PC and the teaching pendant TP.

A drive-control board22is secured to the inner side surface of the back plate7and arranged above the CPU board20. The drive-control board22is formed as a flat plate that extends in directions Y and Z. A surface of the drive-control board22extends parallel with the air vent direction. This arrangement allows the drive-control board22to decrease flow resistance in the air vent direction, thus enhancing the cooling efficiency. A heat generating surface of the drive-control board22, which is, for example, a mounting surface on which circuit elements are mounted, faces inward with respect to the casing2. The drive-control board22is electrically connected to the CPU board20and receives the position instruction signals from the CPU board20. Pairs of connectors, or power supply connectors30and signal connectors32, are arranged on a left side portion of the drive-control board22and spaced at predetermined intervals, extending in an up-and-down direction. In the illustrated embodiment, the drive-control board22has four vertically arranged power supply connectors30and four vertically arranged signal connectors32.

A circuit protector23and a noise filter24connected to the circuit protector23are arranged on a right portion of the drive-control board22.

A front cover25is provided separately from the circuit protector23and the noise filter24. The front cover25is arranged substantially parallel with the drive-control board22. That is, the front cover25is also shaped as a flat plate that extends in directions Y and Z. A surface of the front cover25extends in the air vent direction. This structure allows the front cover25to decrease the flow resistance in the air vent direction. The front cover25has a rectangular opening25aat a position opposed to the power supply connectors30and the signal connectors32. The front cover25also has a circular hole25bat a position opposed to the circuit protector23. A power supply switch SW of the circuit protector23is passed through the hole25b. Pairs of guide rails GR are arranged at opposing sides of the opening25a. The pairs of the guide rails GR are spaced at predetermined intervals in the vertical direction and extend perpendicularly from the front cover25(in direction X ofFIG. 2). Each of the guide rails GR functions as a holding member and holds a corresponding one of motor drivers34, or actuator drivers. The motor drivers34are provided in correspondence with the motors of the robot RB. The motor drivers34are provided to correspond to a plurality of motors90(only one motor is shown) housed in the robot RB. The motors90serve as an actuator. The number of the pairs of the guide rails GR is equal to the number of the motor driver34. In the illustrated embodiment, the front cover25has four pairs of guide rails GR that are vertically arranged. Each pair of the guide rails GR hold the corresponding one of the motor drivers34.

Each of the motor drivers34includes a circuit board35and a heat radiating fin36mounted on the upper side of the circuit board35.

Circuit elements such as a servo amplifier are mounted on the circuit board35. The circuit board35is shaped as a flat plate that extends in directions X and Y. A pair of connectors, or a left connector portion C1and a right connector portion C2, are arranged at an end of the circuit board35. When each pair of the guide rails GR hold the opposing ends of the corresponding circuit board35, the motor driver34connects the connector portions C1, C2to the power supply connector30and the signal connector32, respectively. The heat radiating fin36is, as a whole, shaped as a flat plate that extends in directions X and Y and includes multiple fins each having a heat radiating surface that extends in directions Y and Z.

With the connector portions C1, C2connected to the connectors30,32, respectively, the surface of the circuit board35extends parallel with the air vent direction. In this state, the heat radiating surfaces of the heat radiating fin36also extend parallel with the air vent direction. This arrangement allows the motor drivers34, in the state connected to the drive-control board22, to reduce the flow resistance in the air vent direction, thus improving the cooling efficiency. Each of the motor drivers34is removed from the casing2by retrieving the motor drivers34in a forward direction with respect to the casing2.

A power input terminal40is secured to a right side portion of the opening25aof the front cover25. The power supply cable42is electrically connected to the power input terminal40. The power input terminal40thus receives AC power from an external power supply (not shown). Internal input lines44are secured to the power input terminal40. The internal input lines44extend to the backside of the front cover25and are electrically connected to the noise filter24.

A main power supply board DB is secured to the inner side surface of the top plate6. The main power supply board DB is shaped as a flat plate that extends in directions X and Y. A surface of the main power supply board DB extends parallel with the air vent direction. This arrangement allows the main power supply board DB to decrease the flow resistance in the air vent direction, thus enhancing the cooling efficiency. A heat generating surface of the main power supply board DB, which is, for example, a mounting surface on which circuit elements are mounted, faces inward with respect to the casing2. The main power supply board DB is electrically connected to the circuit protector23through a non-illustrated connection cable. The circuit protector23supplies the AC power to the main power supply board DB from an external power supply. The main power supply board DB distributes the AC power to the CPU board20and the drive-control board22.

A first switching power supply board50is secured to the drive-control board22. The first switching power supply board50is shaped as a flat plate that extends in directions Y and Z. A surface of the first switching power supply board50extends parallel with the air vent direction. This arrangement allows the first switching power supply board50to decrease the flow resistance in the air vent direction, improving the cooling efficiency. A heat generating surface of the first switching power supply board50, which is, for example, a mounting surface on which circuit elements are mounted, faces inward with respect to the casing2. The upper end of the first switching power supply board50is electrically connected to the main power supply board DB and the lower end of the first switching power supply board50is electrically connected to the drive-control board22. The first switching power supply board50converts the AC power provided by the main power supply board DB into DC power and supplies the DC power to the drive-control board22.

A second switching power supply board52is secured to the inner side surface of the right side plate5. The second switching power supply board52is arranged in such a manner as to ensure opening of the vent hole W2. A heat generating surface of the second switching power supply board52, which is, for example, a mounting surface on which circuit elements are mounted, faces inward with respect to the casing2. The upper end of the second switching power supply board52is electrically connected to the main power supply board DB and the lower end of the second switching power supply board52is electrically connected to the CPU board20. The second switching power supply board52converts the AC power provided by the main power supply board DB into DC power and supplies the DC power to the CPU board20.

The CPU board20, the drive-control board22, the main power supply board DB, the first switching power supply board50, and the second switching power supply board52, which are accommodated in the casing2, cooperate with the front cover25, thus defining a substantially linear vent passage having a rectangular cross-sectional shape. Referring toFIG. 2, the opposing ends of the vent passage correspond to the vent holes W1, W2and are open to the exterior of the casing2. Each of the boards is arranged in such a manner that the heat generating surface of the board faces the vent passage and extends parallel with the air vent direction. This reduces the flow resistance in the flow passage. The heat radiating surface of each of the motor drivers34also extends in the air vent direction and is exposed to the vent passage.

In other words, when the cooling fans F send the air to the vent passage, the boards reduce the flow resistance in the vent passage and facilitate the air flowing at increased flow rate in the vent passage. The entire portion of the heat generating surface of each board is thus exposed to the air flowing at the increased flow rate. Also, the entire portion of each of the upper and lower surfaces of each motor driver34is exposed to the air flowing at the increased flow rate.

As a result, the boards and the motor drivers34efficiently perform heat exchange using the air drawn by the cooling fans F, thus improving the cooling efficiency. Further, in the motor drivers34, heat exchange occurs on the upper surface and the lower surface of the motor driver34. The motor driver34, which generates a great amount of heat, is thus further effectively cooled. Also, since the vent passage is defined by a single side surface of each board, the vent passage is sized in correspondence with the sizes of the boards without becoming excessively large.

Therefore, without providing a large-sized cooling fan or a separate cooling duct, the interior of the casing2is efficiently cooled. The size of the robot controller1is thus reduced.

As shown inFIG. 4, the open-close panel8is bent in a stepped shape. The open-close panel8thus has a front surface8a, a projection8b, and a stepped surface8c. The projection8bextends along the entire width of the front surface8aand projects in a normal direction of the front surface8a. The stepped surface8cis one of the side surfaces of projection8band extends in a normal direction of the front surface8a. A relay board51and a non-illustrated third switching power supply board are provided behind the projection8b.

A pair of connectors, or the power supply connector60and the signal connector70, are arranged on the stepped surface8cof the projection8b. The power supply connector60and the signal connector70are electrically connected to the relay board51, which is provided on an inner side of the projection8b. The relay board51is connected to the drive-control board22through a non-illustrated internal power supply line and a non-illustrated internal signal line. The length of the internal power supply line and the length of the internal signal line are selected in such a manner as to prevent interference with the open-close panel8when the open-close panel8opens or closes.

The power supply connector60of the panel8is electrically connected to a connector of a power connection cable62of the robot RB, or a power supply connector64, outside the projection8b. The signal connector70of the panel8is electrically connected to a connector of a signal connection cable72of the robot RB, or a signal connector74, outside the projection8b. When the power supply connector60is connected to the power supply connector64, the power connection cable62extends from the power supply connector64in a normal direction of the stepped surface8c, or in a direction parallel with the front surface8a. When the signal connector70is connected to the signal connector74, the signal connection cable72extends from the signal connector74in a normal direction of the stepped surface8c, or in a direction parallel with the front surface8a.

This arrangement prevents the cables62,72of the robot controller1from projecting forward (in the direction opposite to direction X) from the casing2when the robot RB is in operation. As a result, even if the cables62,72exhibit poor flexibility, the space occupied by the robot controller1is reduced.

A hole8dthrough which the power input terminal40passes is defined at a position opposed to the terminal40and extends through the front surface8aof the open-close panel8. A slit8eextends from the hole8dto the right side end of the open-close panel8. A cup-shaped cover case80covers the hole8d. A recess80ais defined at the right side of the cover case80and extends continuously from the slit8e. When the open-close panel8is held in a closed state, the slit8eand the recess80aare engaged with the power supply cable42. This arrangement allows the power supply cable42to smoothly extend to the exterior of the open-close panel8regardless of whether the open-close panel8is held in an open state or the closed state.

A circular through hole84is defined in the front surface8aof the open-close panel8and arranged below the cover case80. A power supply switch SW of the circuit protector23is passed through the through hole84. This allows manipulation of the power supply switch SW from outside the casing2.

Next, operation of the robot controller1, which has the above-described configuration, will be explained.

With reference toFIG. 1, the personal computer PC and the teaching pendant TP are connected to the robot controller1through the connection cables13,14. Further, the robot RB is connected to the robot controller1through the connection cable62and the cable72.

When the power supply switch SW of the robot controller1is turned on and the power is supplied to the robot controller1, the cooling fans F start operating. When prescribed drive signals are input from the personal computer PC and the teaching pendant TP to the robot controller1, the robot controller1generates a position instruction signal in correspondence with the drive signals and controls operation of the robot RB in accordance with the position instruction signal.

Meanwhile, the boards, which are the CPU board20, the drive-control board22, the main power supply board DB, the first switching power supply board50, and the second switching power supply board52, and the motor drivers34continuously generate heat from the circuit elements mounted on the boards and the motor drivers34.

In this state, the cooling fans F continuously draw the air through the vent hole W1and discharge the air through the vent hole W2. Since the surfaces of the boards extend parallel with the air vent direction in this state, the air flows at an increased flow rate. The heat generating surfaces of the boards and the upper and lower surfaces of the motor drivers34are exposed to the air flowing at the increased flow rate. That is, the boards and the motor drivers34are further efficiently cooled through heat exchange occurring in correspondence with the respective heat generation amounts.

As a result, the air drawn by the cooling fans F achieves efficient heat exchange in the robot controller1, thus enhancing the cooling efficiency.

The illustrated embodiment has the following advantages.

The CPU board20, the drive-control board22, and the main power supply board DB are secured to the inner side surface of the base portion3, the back plate7, and the top plate6, respectively, and define the vent passage. The motor drivers34, which generate a great amount of heat, are provided in the vent passage. The vent holes W1, W2are defined in the side plates4,5. The cooling fans F are provided in the vent passage and cause the air to flow through the vent passage.

Therefore, the surfaces of the boards extend parallel with the air vent direction and thus reduce the flow resistance in the vent passage. Further, since the vent passage is defined by one of the side surfaces of each board, the vent passage is sized in correspondence with the sizes of the boards without becoming excessively large. As a result, the interior of the casing2is efficiently cooled without providing a large-sized cooling fan or a separate cooling duct. This reduces the size of the robot controller1.

Also, each of the motor drivers34, which generate a large amount of heat, is entirely exposed to the air flow. The components are thus cooled in correspondence with the amount of the heat generated by themselves, further enhancing the cooling efficiency of the robot controller1.

The first switching power supply board50is arranged between and connected to the main power supply board DB and the drive-control board22. The second switching power supply board52is arranged between and connected to the main power supply board DB and the CPU board20. This arrangement shortens the length of the cables extending between the boards. The size of the robot controller1is thus further reduced.

The open-close panel8is selectively opened and closed through the hinge H. The drive-control board22is secured to the back plate7. The motor drivers34are attachable and detachable in a rearward direction and a forward direction. Therefore, simply by opening the open-close panel8, the motor drivers34are replaced easily. This facilitates maintenance of the robot controller1.

The open-close panel8has the stepped surface8cand the connectors60,70are secured to the stepped surface8c. This allows the cables62,72to extend along the front surface8a. In other words, the cables62,72(the connectors64,74) are prevented from projecting forward. This reduces the space occupied by the robot controller1.

The connection state of the connectors60,64and the connection state of the connectors70,74are visible simply by opening the open-close panel8. This facilitates attachment and detachment of the connectors64,74.

The connection cables13,14are connected to the front surface3aof the base portion3. The power supply cable42is connected to the front cover25. This arrangement allows attachment and detachment of all the cables13,14,42,62,72and the motor drivers34from the front side of the robot controller1. The maintenance of the robot controller1is thus further facilitated.

The illustrated embodiment may be modified in the following forms.

As long as the CPU board20, the drive-control board22, and the main power supply board DB are arranged in such a manner as to define the vent passage, each of the boards20,22, DB may be attached to any one of the base portion3, the back plate7, and the top plate6. For example, the CPU board20may be secured to the inner side surface of the top plate6and the main power supply board DB may be secured to the base portion3.

The first and second switching power supply boards50,52may be secured to any ones of the side plates of the casing2, other than the back plate7and the right side plate5. For example, the first switching power supply board50may be secured to the top plate6on which the main power supply board DB is arranged. The second switching power supply board52may be secured to the top plate6on which the main power supply board DB is arranged or the bottom plate3on which the main control board20is provided.

As long as the motor drivers34are arranged in the vent passage, the motor drivers34may be aligned in any suitable direction.

The stepped surface8cmay be omitted.

Any side plate of the casing2other than the front side plate may be selectively opened and closed. Alternatively, all of the side plates of the casing2may be held in a closed state.

The power supply connection cable62and the signal connection cable72may be formed by a single common cable.

Any suitable devices other than the personal controller PC and the teaching pendant TP, for example an emergency stop switch and a programmable logic controller, may be connected to the robot controller1.

The robot RB is not restricted to the horizontally articulated type four-axis control industrial robot but may be, for example, a single-axis or two-axis or three-axis control industrial robot or five-or-more-axis control industrial robot (for example, a vertically articulated type six-axis control industrial robot). In these cases, the motor drivers34corresponding to the motors90housed in the robot RB are installed in the robot controller1.