Robot

A robot includes: an arm; a shaft supported at a tip of the arm so as to be movable in a direction of a predetermined axis; a power transmitting unit fixed to the arm and connected to a power supply; and a power receiving unit and a battery that are fixed to the shaft. In a state in which the shaft is positioned at a predetermined position in the direction of the axis, the power receiving unit is close to the power transmitting unit to wirelessly receive power transmitted from the power transmitting unit, and the battery stores the power received by the power receiving unit and uses the power as a power source of a device attached to the shaft.

TECHNICAL FIELD

The present disclosure relates to a robot.

BACKGROUND

A known SCARA robot includes a shaft supported so as to be movable in the vertical direction with respect to an arm, and a power supply device that supplies, in a non-contact manner, power to a tool attached to the lower end of the shaft (for example, see Employed in SCARA robot! Solution to disconnection in rotating handling part of robot!”, [online], [searched on Nov. 30, 2020], Internet <URL: https://www.b-plus-kk.jp/blog/2017/11/13/254). In this SCARA robot, the power supply device is attached to the upper end of the shaft, and, when the shaft is moved up or down with respect to the arm, the entire power supply device is moved up or down together with the shaft.

SUMMARY

An aspect of the present disclosure is a robot including: an arm; a shaft supported at a tip of the arm so as to be movable in a direction of a predetermined axis; a power transmitting unit fixed to the arm and connected to a power supply; and a power receiving unit and a battery that are fixed to the shaft. In a state in which the shaft is positioned at a predetermined position in the direction of the axis, the power receiving unit is brought close to the power transmitting unit to wirelessly receive power transmitted from the power transmitting unit, and the battery stores the power received by the power receiving unit and uses the power as a power source of a device attached to the shaft.

DETAILED DESCRIPTION OF EMBODIMENTS

A robot1according to an embodiment of the present disclosure will be described below with reference to the drawings.

The robot1according to this embodiment is, for example, a horizontal articulated type robot as illustrated inFIG.1. The robot1includes a base2installed on a horizontal floor surface, and a first arm3supported so as to be rotatable about a first axis (first vertical axis) A extending in the vertical direction with respect to the base2. The robot1includes a second arm (arm)4supported so as to be rotatable about a second axis (second vertical axis) B, which is parallel to the first axis A, with respect to the first arm3, and a shaft5supported by the second arm4so as to be able to move up and down along a third axis (axis) C, which is parallel to the first axis A.

The robot1also includes a power transmitting unit7attached to the second arm4, and a power receiving unit8and a battery9fixed to a tool (device)6attached to a tip of the shaft5. By being fixed to the tool6, the power receiving unit8and the battery9are indirectly fixed to the shaft5via the tool6.

As shown inFIG.2, the robot1is connected to a controller101by a cable10connected to the base2, and the controller101is connected to a power supply100. A duct11is connected between the base2and the second arm4, and cables12wired from the base2to the second arm4are accommodated in the duct11.

FIG.2illustrates only the cable12connected to the power transmitting unit7(described below). The cable10and the cables12transmit power, control signals, and the like from the controller101.

The base2is provided with a first transmitter/receiver22for transmitting and receiving control signals by wireless communication. The first transmitter/receiver22may be disposed in the controller101or may be disposed at another position, such as the second arm4.

The shaft5is a ball-screw spline shaft passing through a tip portion of the second arm4in the vertical direction. The shaft5is supported by a ball screw nut41disposed in the second arm4so as to be able to move up and down along the third axis C, and is also supported by a ball spline nut42disposed in the second arm4so as to be rotatable about the third axis C. The ball screw nut41and the ball spline nut42are supported so as to be rotatable about the third axis C and are each rotationally driven by a motor (not shown).

As shown in, for example,FIG.3, the tool6is a hand that performs work, such as gripping a workpiece W. The tool6includes a hand base61fixed to the lower end of the shaft5, a pair of fingers62supported by the hand base61, and a servo motor63that drives the fingers62to open and close. As shown inFIGS.2and5, the tool6is provided with a tool controller64for controlling the tool6, and a second transmitter/receiver65for wirelessly transmitting/receiving control signals to/from the first transmitter/receiver22.

The battery9is connected to the power receiving unit8and the tool controller64.

The power transmitting unit7is fixed to the lower surface of the second arm4, and the cable12introduced into the second arm4through the duct11is connected to the power transmitting unit7.

The power receiving unit8is fixed to the upper surface of the hand base61. As shown inFIG.2, in a state in which the shaft5is positioned at the uppermost position in the motion range in the vertical direction and is positioned at a predetermined angle about the third axis C (charging position), the power receiving unit8is disposed at a position facing the power transmitting unit7with a predetermined gap therebetween in the vertical direction.

In a state in which the power transmitting unit7and the power receiving unit8face each other, the power transmitted through the cable12is transmitted from the power transmitting unit7to the power receiving unit8in a non-contact manner, and the battery9is charged with the power. The tool controller64controls the servomotor63in accordance with the control signals wirelessly transmitted from the first transmitter/receiver22to operate the tool6.

The operation of the thus-configured robot1according to this embodiment will be described.

In order to perform work with the tool6by using the robot1according to this embodiment, the shaft5is operated to position the tool6at a charging position with respect to the second arm4, as illustrated inFIG.2, so that the power receiving unit8faces the power transmitting unit7. In this state, power is transmitted from the power transmitting unit7to the power receiving unit8in a non-contact manner, and the battery9is charged with the power received by the power receiving unit8.

By operating the ball screw nut41and the ball spline nut42in a state in which the battery9has been appropriately charged, the shaft5is moved up or down and rotated about the third axis C to position the tool6at a desired position.

For example, as shown inFIG.4, in a state in which the power transmitting unit7and the power receiving unit8are away from each other, the supply of power from the power transmitting unit7is stopped. Hence, the tool6is controlled by the tool controller64provided in the tool6with the power charged in the battery9.

Specifically, as shown inFIG.5, the second transmitter/receiver65receives a control signal wirelessly transmitted from the first transmitter/receiver22. The tool controller64is supplied with power from the battery9and receives a control signal from the second transmitter/receiver65. Then, the tool controller64supplies power to the servo motor63on the basis of the input control signal.

This way, the robot1can drive the tool6disposed at a position other than the charging position and perform a desired operation.

In this case, in the robot1according to this embodiment, the second arm4and the shaft5are not connected by a movable cable. Hence, the shaft5can perform up/down operations and rotating operations about the third axis C with respect to the second arm4without being restricted by the movable cable. Hence, it is possible to ensure a wide motion range for the shaft5.

In addition, because the power transmitting unit7is fixed to the second arm4, even when the shaft5is displaced with respect to the second arm4, the cable12connected to the power transmitting unit7can be maintained in a stationary state in the second arm4. Therefore, it is possible to prevent the cable12from being repeatedly deformed with the movement of the shaft5and to improve the durability of the robot1.

In addition, in the robot1according to this embodiment, it is only necessary to operate the shaft5with respect to the second arm4in order to charge the battery9provided in the tool6. Specifically, because there is no need to operate the first arm3and the second arm4for charging, the moving distance of the tool6for charging can be minimized. This can minimize the time required for the operation for charging, and can also reduce the possibility of interference between the tool6and a peripheral object due to the operation for charging.

By minimizing the time required for the operation for charging, not only can charging be performed in the waiting time between operations by the tool6, but also charging can be performed during the operation by frequently moving the tool6to the charging position. This leads to an advantages that the capacity of the battery9can be reduced and the weight thereof can be reduced.

Although the power transmitting unit7is fixed to the second arm4in this embodiment, the power transmitting unit7may be removably attached to the second arm4instead.

For example, the lower surface of the second arm4may be provided with a screw hole (attaching portion) to which a bolt for removably attaching the power transmitting unit7will be fastened. With this configuration, if a failure or the like occurs in the power transmitting unit7, it is possible to remove only the power transmitting unit7from the second arm4for maintenance and thus to improve maintainability.

Furthermore, by providing screw holes for attaching the power transmitting unit7at multiple positions, the power transmitting unit7can be attached at an appropriate position in accordance with the position of the power receiving unit8disposed on the tool6.

Although one power transmitting unit7and one power receiving unit8are provided in this embodiment, instead, at least one of the power transmitting unit7and the power receiving unit8may be provided in multiple numbers.

With such a configuration, multiple charging positions, where the tool6is disposed when the battery9is charged, can be set. Hence, it is possible to select a charging position that requires the minimum moving distance of the shaft5depending on the position of the shaft5immediately before charging the battery9and thus to further improve the efficiency of the charging operation.

Although the power receiving unit8and the battery9are provided on the tool6in this embodiment, they may be fixed to the shaft5separately from the tool6.

Furthermore, in this embodiment, the power transmitting unit7is fixed to the lower surface of the second arm4, and the power receiving unit8is fixed to the upper surface of the tool6, so that the power transmitting unit7and the power receiving unit8face each other in the vertical direction at the charging position. Instead of this, the power transmitting unit7may be fixed to the upper surface of the second arm4, and the power receiving unit8may be made to face the upper part of the power transmitting unit7at the charging position. Alternatively, the power transmitting unit7and the power receiving unit8may be disposed at positions facing each other in the radial direction around the third axis C at the charging position.

This configuration allows the power transmitting unit7and the power receiving unit8to be disposed at positions unlikely to interfere with peripheral devices.

In this embodiment, the battery9may be charged during the movement of the first arm3and the second arm4.

For example, the tool6may be disposed at a predetermined charging position with respect to the second arm4whose posture is being drastically changed while the first arm3and the second arm4are rotated about the first axis A and the second axis B, respectively, in order to switch from the current step to the next step.

By doing so, it is possible to charge the battery9while effectively using time required for switching steps and thus to improve the work efficiency of the robot1.

Although an example of the robot1is a horizontal articulated type robot in this embodiment, the robot1is not limited thereto, and it may be applied to any type of robot that supports the tool6so as to be movable in a predetermined axial direction.

Furthermore, although an example of the tool6is a hand in this embodiment, the tool6is not limited thereto and may be any tool such as a machining tool, a coating tool, or a cleaning tool.

Furthermore, although an example of an electric actuator of the tool6is the servomotor63in this embodiment, the electric actuator is not limited thereto and may be any actuator, such as an electromagnetic valve or an electromagnet, that is driven by electricity.