JP7182720B2 - Portable machine tool - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable machine tool, and more particularly to a portable machine tool in which machining is performed while a machine tool body is fixed to a workpiece by an electromagnet.

2. Description of the Related Art Among machine tools such as drilling machines, there are portable machine tools that can be carried to a work site to perform machining work on a workpiece. Such a portable machine tool can be fixed to the work piece by various methods, but in consideration of ease of handling and convenience, the machine tool is fixed to the work piece by magnetic attraction using an electromagnet. there is something (Patent document 1)

JP 2014-231129 A

When the machine tool body is fixed to the workpiece by an electromagnet, when the power supply to the machine tool is stopped, the magnetic attraction force of the electromagnet drops rapidly, and the machine tool body can be fixed with sufficient force. I can't do it. In particular, while processing tools such as drills are being used for processing, portable machine tools are subject to a reaction force that accompanies processing work. It is dangerous if the portable machine tool floats up or falls down.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a portable machine tool capable of improving safety when power supply is stopped.

That is, the present invention
machine tool body;
an electromagnet attached to the machine tool body for fixing the machine tool body to a workpiece;
an electric motor for driving a machining tool attached to the machine tool body so as to perform a machining operation on the workpiece;
a control unit operated by power supplied from a main power supply and configured to control the electromagnet and the electric motor;
a power storage member for a control unit connected to the control unit;
with
When power supply from the main power supply to the control unit is stopped, the operation of the control unit is continued by power stored in the power storage member for the control unit,
When the control unit determines that the power supply from the main power supply has stopped while the electromagnet is operating and the electric motor is being driven, the electric motor is stopped and the electromagnet is kept operating. To provide a portable machine tool configured to perform control so as to allow

In the portable machine tool, when the power supply from the main power supply is stopped while the electromagnet is operating and the electric motor is driving, the control unit continues to operate with the power of the power storage member for the control unit, Control is performed so that the driving of the electric motor is stopped and the operation of the electromagnet is continued. As a result, while the magnetic attraction by the electromagnet continues, the electric motor in operation is stopped to stop the driving of the machining tool, so that the portable machine tool is lifted up or overturned by the reaction force received from the machining tool. It is possible to prevent it from slipping.

again,
further comprising an electromagnet power storage member connected to the electromagnet,
When power supply from the main power supply is stopped while the electromagnet is operating, power can be supplied from the electromagnet power storage member to the electromagnet.

This allows the operation of the electromagnet to continue longer after the power supply has stopped.

Further, when the power supply from the main power source is temporarily stopped and the power supply from the main power source is resumed while the control unit continues to operate with the power of the power storage member for the control unit. , the control unit stops driving the electric motor and continues the state in which the operation of the electromagnet is maintained.

Further, the control unit detects a current flowing through the electric motor while the electric motor is being driven, and stops the power supply from the main power supply when the current flowing through the electric motor becomes equal to or less than a predetermined threshold value. It can be made to judge that it stopped.

or,
The main power supply is a battery having a connection detection terminal,
The machine tool main body is adapted to detachably mount the battery, and has a main body side terminal connected to the connection detection terminal when the battery is mounted,
When the control unit detects that the electric current flowing through the electric motor is equal to or less than a predetermined threshold value and that the connection between the connection detection terminal and the body-side terminal is disconnected, the power supply from the main power supply is stopped. It can be made to judge that it stopped.

This makes it possible to determine that the power supply has stopped due to the removal of the battery, rather than due to a circuit failure or the like.

again,
further comprising a display unit for displaying the state of the portable machine tool,
When the power supply from the main power source is stopped and the power supply from the main power source is resumed while the control unit continues to operate with the power of the power storage member for the control unit, the power supply is temporarily interrupted. The display unit can be configured to display that the motor has been temporarily stopped.

Specifically, the power storage member for the control section is a capacitor, and the capacitor can be charged with electric power supplied from the main power supply.

An embodiment of a portable machine tool according to the present invention will be described below with reference to the accompanying drawings.

1 is a side view of a portable machine tool according to an embodiment of the present invention; FIG. FIG. 2 is a sectional view of the portable machine tool of FIG. 1; FIG. 2 is a functional block diagram of the portable machine tool of FIG. 1; 4 is a first flow chart showing the operation of the portable machine tool of the present invention; 4 is a second flow chart showing the operation of the portable machine tool of the present invention;

A portable machine tool 1 according to one embodiment of the present invention includes a machine tool main body 10 and an electromagnet 12 attached to the lower side of the machine tool main body 10, as shown in FIG. A battery 14 serving as a main power source for the portable machine tool 1 is detachably attached to the rear of the machine tool body 10 . As shown in FIG. 2, the machine tool main body 10 includes a working tool mounting portion 18 to which an annular cutter 16 (working tool) is detachably mounted. An electric motor 20 is provided for this purpose. The machining tool mounting portion 18 and the electric motor 20 are drivingly connected via a gear mechanism 22 comprising a plurality of gears. As shown in FIG. 1 , a lever 24 is attached to the machine tool body 10 , and by pivoting the lever 24 , the machining tool attachment portion 18 is moved up and down together with the annular cutter 16 . As shown in FIG. 2, the electromagnet 12 has a ring-shaped first coil 26 and a ring-shaped second coil 30 as well. When power is supplied from the battery 14 to the first coil 26 and the second coil 30 while the portable machine tool 1 is placed on a magnetic material, the machine tool main body is moved by the magnetic attraction force generated by the electromagnet 12. 10 is fixed with respect to the workpiece, which is a magnetic material. The portable machine tool 1 presses an annular cutter 16 rotationally driven by an electric motor 20 against the workpiece while the machine tool main body 10 is fixed to the workpiece by the electromagnet 12 . It is a drilling machine designed to perform processing operations on objects.

As shown in FIG. 1, a motor drive switch 34 for starting driving the electric motor 20, a motor stop switch 36 for stopping driving the electric motor 20, and an electromagnet 12 are provided on the side of the machine tool body 10. An electromagnet switch 38 is provided for starting and stopping the operation of the. A lighting switch 40 is also arranged on the side surface of the machine tool main body 10 . The lighting switch 40 is used to turn on and off a lighting device (not shown) arranged on the lower front surface of the machine tool body 10 . These switches 34, 36, 38, and 40 are push-button momentary switches that are ON only while being pressed and return OFF when released. The machine tool main body 10 is further provided with an LED display section 41 for indicating the state of the portable machine tool 1 to the operator.

As shown in FIG. 2, a magnetic sensor 42 is attached to the electromagnet 12 . The magnetic sensor 42 is adapted to measure the magnitude of magnetic flux density in the magnetic circuit of the electromagnet 12 formed around the electromagnet 12 through the workpiece.

The portable machine tool 1 has a control circuit board 46 in the machine tool main body 10, and the control circuit board 46 is provided with a control section 48 (FIG. 3) for controlling the electric motor 20, the electromagnet 12, and the like. ing. When the battery 14 is attached to the machine tool main body 10, power is supplied from the battery 14 to the control unit 48 through the control power supply circuit 50, and the control unit 48 is activated. The control unit 48 drives the electric motor 20 and operates the electromagnet 12 according to the operating states of the motor drive switch 34, the motor stop switch 36, and the electromagnet switch 38 and the operating state of the portable machine tool 1 at that time. Control. The controller 48 controls the rotation speed of the electric motor 20 by transmitting a control signal to the motor controller 52 while driving the electric motor 20 . At this time, the control unit 48 monitors the load condition of the electric motor 20 by detecting the amount of current flowing through the electric motor 20 with the motor current detection unit 54 . The control unit 48 controls power supplied to the first coil 26 and the second coil 30 via the coil control circuit 56 when the electromagnet 12 is operating. Since the first coil 26 and the second coil 30 are connected in series, the power supplied to the first coil 26 and the second coil 30 will generally be the same. The coil disconnection detection circuit 58 detects currents flowing through the first coil 26 and the second coil 30 to detect disconnection of the first coil 26 and the second coil 30 . When disconnection of the first coil 26 or the second coil 30 is detected, the control unit 48 stops control and turns on the LED display unit 41 to inform the user that the coils 26, 30 are disconnected. Further, the control unit 48 stores that the coils 26 and 30 are disconnected, and lights the LED display unit 41 when the battery 14 is once disconnected and then reconnected and the control of the control unit 48 is resumed. It also informs the user that the coils 26, 30 are disconnected.

The control circuit board 46 further includes a control unit capacitor 60 (control unit power storage member) connected to the control unit 48 and an electromagnet capacitor 62 (electromagnet power storage member) connected to the electromagnet 12 . The controller capacitor 60 and the electromagnet capacitor 62 are charged with electric power supplied from the battery 14 when the battery 14 is connected. When the power supply from the battery 14 is stopped, the operation of the control unit 48 is continued by the power stored in the control capacitor 60, and the operation of the electromagnet 12 is continued by the power stored in the electromagnet capacitor 62. It has become so.

The battery 14 has a connection detection terminal 64, and when the battery 14 is attached to the machine tool main body 10, the connection detection terminal 64 is connected to a main body side terminal 66 provided on the machine tool main body 10. . The control unit 48 detects the connection state between the main body side terminal 66 and the connection detection terminal 64 .

4 and 5 show the operation of the portable machine tool 1 when the coils 26, 30 of the electromagnet 12 are not disconnected. When the battery 14 is attached to the machine tool main body 10 and power is supplied to the controller 48, control by the controller 48 is started (S10). When the electromagnet switch 38 is pushed and turned from the OFF state to the ON state (S12), the control section 48 starts operating the electromagnet 12 via the coil control circuit 56 (S14). When the electromagnet 12 operates, the portable machine tool 1 is fixed to the workpiece by the magnetic attraction force of the electromagnet 12 . In this state, when the motor drive switch 34 is pushed from the OFF state to the ON state (S16), the control unit 48 starts driving the electric motor 20 (rotating the machining tool mounting unit 18) via the motor control unit 52. (S18).

When the driving of the electric motor 20 is started, the control unit 48 detects the electric current of the electric motor 20 . If the electric current of the electric motor 20 is not equal to or less than the predetermined threshold A[A] (S20), the driving of the electric motor 20 is continued. Here, A[A], which is the threshold value, is a value that is so small that it cannot occur when power is normally supplied from the battery 14 . When any one of the motor drive switch 34, the motor stop switch 36, and the electromagnet switch 38 is pressed to turn ON while the electric motor 20 continues to be driven (S22), the controller 48 stops the electric motor. 20 is stopped (S24). The electric motor 20 may be stopped only when the motor stop switch 36 is pressed. 38 may be pushed, and by stopping the driving of the electric motor 20 even in such a case, a dangerous state can be more reliably avoided.

When the controller 48 detects that the current of the electric motor 20 is A[A] or less (S20), it stops driving the electric motor 20 (S24). is connected to the terminal 64 (S26). When the connection between the body-side terminal 66 and the connection detection terminal 64 is disconnected, the control section 48 determines that the battery 14 is detached from the machine tool body 10 and power supply from the battery 14 is stopped. (S28) and stored in the memory. When the battery 14 is detached from the machine tool main body 10 and the power supply from the battery 14 is stopped, the control section 48 continues to operate with the power stored in the control section capacitor 60 . At this time, the electromagnet 12 is in operation and the control unit 48 is controlled to continue the operation of the electromagnet 12, but the electromagnet 12 continues to operate with the electric power stored in the electromagnet capacitor 62. Even after the power supply to the electromagnet 12 is stopped, the electromagnet 12 is magnetized by the operation up to that point. Further, when the electric motor 20 stops due to the stop of the electric power supply, an electromotive force is generated in the electric motor 20 and a certain amount of electric power is supplied to the electromagnet 12. Therefore, the operation of the electromagnet 12 is also caused by the electric power. Continued.

After stopping the driving of the electric motor 20 (S24), the control unit 48 checks the voltage supplied from the battery 14, and if it is greater than a predetermined C [V] (S30), the battery 14 is It is determined that the battery 14 is attached to the main body 10 and continues to supply power, or that the battery 14 has been detached and reattached to restart the power supply, and the control shown in FIG. 5 is performed. Here, C[V] is a voltage value large enough to operate the control unit 48, the electric motor 20, and the electromagnet 12 normally. The control unit 48 stops driving the electric motor 20 when the power supply from the battery 14 is resumed while the power supply from the battery 14 is stopped and the operation is continued with the power of the control unit capacitor 60. and the state in which the operation of the electromagnet 12 is maintained is continued.

As shown in FIG. 5, the control unit 48 checks whether the battery 14 is temporarily disconnected in the above control (S32). If it is determined in S28 that the battery 14 has been disconnected (S32), the control section 48 lights the LED display section 41 to inform the operator that the battery 14 has been temporarily disconnected (S34). When one of the switches 34, 36, and 38 is pressed to turn on the LED display section 41 (S36), the control section 48 turns off the LED display section 41 (S38). By turning on the LED display unit 41, the operator can be prompted to check the mounting state of the battery 14. FIG. When the motor drive switch 34 is pressed to turn it ON while the LED display 41 is off (S40), the process returns to S18 in FIG. 4 and the electric motor 20 is started again. When the motor drive switch 34 is not pushed and the electromagnet switch 38 is pushed and turned on (S42), the operation of the electromagnet 12 is stopped (S44). This completes a series of controls (S46), and the control of the controller 48 returns to S10.

While the annular cutter 16 is machining, the rotating annular cutter 16 receives a reaction force from the workpiece and the force is transmitted to the portable machine tool 1, but normally the electromagnet 12 has a sufficient magnetic attraction force. Since the portable machine tool 1 is firmly fixed by , there is no danger that the portable machine tool 1 will be lifted up or overturned by the reaction force. However, when the power supply from the battery 14 is stopped, the magnetic attraction force of the electromagnet 12 is abruptly reduced, so there is a risk that the portable machine tool 1 may topple over due to the reaction force. In the portable machine tool 1, when the electric power supply from the battery 14 is stopped while the electromagnet 12 is being operated and the electric motor 20 is being driven as described above, the control unit 48 outputs the electric power of the control unit capacitor 60. , the operation is continued, the driving of the electric motor 20 is stopped, and the operation of the electromagnet 12 is continued. As a result, while the magnetic attraction by the electromagnet 12 continues, the electric motor 20 that is being driven is stopped to stop the rotation of the circular cutter 16 , and the portable machine tool 1 receives a reaction force from the circular cutter 16 . It is possible to prevent the user from falling down.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, instead of the annular cutter, the machine tool may be configured so that other end tools such as a drill can be attached. In the above embodiment, one battery is used as the main power source to supply electric power to the electric motor, electromagnets, and control unit. You can also Also, an external power source such as an AC power source may be used instead of the battery. A primary battery or a secondary battery can be used instead of a capacitor as a power storage member for supplying power to the control unit and the electromagnet when the power supply is stopped. Moreover, the electric storage member for electromagnets is not necessarily required. The determination that the power supply has stopped due to disconnection of the battery or the like may be made based on only one of the current amount of the electric motor and the connection between the connection detection terminals of the battery. Alternatively, the supply voltage from the main power supply may be directly detected to determine that the power supply has stopped.

1 Portable Machine Tool 10 Machine Tool Body 12 Electromagnet 14 Battery 16 Annular Cutter 18 Machining Tool Attachment 20 Electric Motor 22 Gear Mechanism 24 Lever 26 First Coil 30 Second Coil 34 Motor Drive Switch 36 Motor Stop Switch 38 Electromagnet Switch 40 Lighting Switch 41 LED display unit 42 Magnetic sensor 46 Control circuit board 48 Control unit 50 Control power supply circuit 52 Motor control unit 54 Motor current detection unit 56 Coil control circuit 58 Coil disconnection detection circuit 60 Control unit capacitor 62 Electromagnet capacitor 64 Connection detection terminal 66 Main body side terminal

Claims (6)

machine tool body;
an electromagnet attached to the machine tool body for fixing the machine tool body to a workpiece;
an electric motor for driving a machining tool attached to the machine tool body so as to perform a machining operation on the workpiece;
a control unit operated by power supplied from a main power supply and configured to control the electromagnet and the electric motor;
a power storage member for a control unit connected to the control unit;
an electromagnet power storage member connected to the electromagnet;
with
When power supply from the main power supply to the control unit is stopped, the operation of the control unit is continued by power stored in the power storage member for the control unit,
When the control unit determines that the power supply from the main power supply has stopped while the electromagnet is operating and the electric motor is being driven, the electric motor is stopped and the electromagnet is kept operating. It is designed to control to let
A portable machine tool configured to supply electric power to the electromagnet from the electric storage member for the electromagnet when power supply from the main power source is stopped during operation of the electromagnet . machine tool body;
an electromagnet attached to the machine tool body for fixing the machine tool body to a workpiece;
an electric motor for driving a machining tool attached to the machine tool body so as to perform a machining operation on the workpiece;
a control unit operated by power supplied from a main power supply and configured to control the electromagnet and the electric motor;
a power storage member for a control unit connected to the control unit;
with
When power supply from the main power supply to the control unit is stopped, the operation of the control unit is continued by power stored in the power storage member for the control unit,
When the control unit determines that the power supply from the main power supply has stopped while the electromagnet is operating and the electric motor is being driven, the electric motor is stopped and the electromagnet is kept operating. It is designed to control to let
When the power supply from the main power source is temporarily stopped and the power supply from the main power source is resumed while the control unit continues to operate with the power of the power storage member for the control unit, A portable machine tool , wherein a control unit stops driving an electric motor and continues the state in which the operation of the electromagnet is maintained. machine tool body;
an electromagnet attached to the machine tool body for fixing the machine tool body to a workpiece;
an electric motor for driving a machining tool attached to the machine tool body so as to perform a machining operation on the workpiece;
a control unit operated by power supplied from a main power supply and configured to control the electromagnet and the electric motor;
a power storage member for a control unit connected to the control unit;
with
When power supply from the main power supply to the control unit is stopped, the operation of the control unit is continued by the electric power stored in the power storage member for the control unit,
When the control unit determines that the power supply from the main power supply has stopped while the electromagnet is operating and the electric motor is being driven, the electric motor is stopped and the electromagnet is kept operating. It is designed to control to let
The control unit detects a current flowing through the electric motor while the electric motor is being driven, and determines that the power supply from the main power supply has stopped when the current flowing through the electric motor falls below a predetermined threshold. A portable machine tool made to judge. machine tool body;
an electromagnet attached to the machine tool body for fixing the machine tool body to a workpiece;
an electric motor for driving a machining tool attached to the machine tool body so as to perform a machining operation on the workpiece;
a control unit operated by power supplied from a main power supply and configured to control the electromagnet and the electric motor;
a power storage member for a control unit connected to the control unit;
with
When power supply from the main power supply to the control unit is stopped, the operation of the control unit is continued by power stored in the power storage member for the control unit,
When the control unit determines that the power supply from the main power supply has stopped while the electromagnet is operating and the electric motor is being driven, the electric motor is stopped and the electromagnet is kept operating. It is designed to control to let
The main power supply is a battery having a connection detection terminal,
The machine tool main body is adapted to detachably mount the battery, and has a main body side terminal connected to the connection detection terminal when the battery is mounted,
When the control unit detects that the electric current flowing through the electric motor is equal to or less than a predetermined threshold value and that the connection between the connection detection terminal and the body-side terminal is disconnected, the power supply from the main power supply is stopped. A portable machine tool that is determined to have stopped. machine tool body;
an electromagnet attached to the machine tool body for fixing the machine tool body to a workpiece;
an electric motor for driving a machining tool attached to the machine tool body so as to perform a machining operation on the workpiece;
a control unit operated by power supplied from a main power supply and configured to control the electromagnet and the electric motor;
A portable machine tool comprising
a power storage member for a control unit connected to the control unit;
a display unit that displays the state of the portable machine tool;
further comprising
When power supply from the main power supply to the control unit is stopped, the operation of the control unit is continued by the electric power stored in the power storage member for the control unit,
When the control unit determines that the power supply from the main power supply has stopped while the electromagnet is operating and the electric motor is being driven, the electric motor is stopped and the electromagnet is kept operating. It is designed to control to let
When the power supply from the main power supply is stopped and the power supply from the main power supply is resumed while the control unit continues to operate with the power of the power storage member for the control unit, the power supply is temporarily interrupted. The portable machine tool is adapted to indicate that the machine tool has been stopped. 6. The portable machine tool according to any one of claims 1 to 5 , wherein said power storage member for control section is a capacitor, and said capacitor is configured to store power supplied from said main power supply.

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