Electric Power Tool
First Claim
1. An electric power tool comprising:
- a brushless motor having a plurality of stator windings and configured to rotate in accordance with voltages applied to the plurality of stator windings, an induced voltage being generated in accordance with a rotation of the brushless motor;
a rectifier circuit configured to rectify an AC voltage;
a smoothing capacitor configured to smooth the AC voltage rectified by the rectifier circuit to a pulsation voltage having a maximum value larger than the induced voltage and a minimum value smaller than the induced voltage; and
an inverter circuit configured to perform switching operations to output the pulsation voltage to the plurality of stator windings by rotation.
2 Assignments
0 Petitions
Accused Products
Abstract
An electric power tool includes: a brushless motor having a plurality of stator windings and configured to rotate in accordance with voltages applied to the plurality of stator windings, an induced voltage being generated in accordance with a rotation of the brushless motor; a rectifier circuit configured to rectify an AC voltage; a smoothing capacitor configured to smooth the AC voltage rectified by the rectifier circuit to a pulsation voltage having a maximum value larger than the induced voltage and a minimum value smaller than the induced voltage; and an inverter circuit configured to perform switching operations to output the pulsation voltage to the plurality of stator windings by rotation.
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Citations
20 Claims
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1. An electric power tool comprising:
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a brushless motor having a plurality of stator windings and configured to rotate in accordance with voltages applied to the plurality of stator windings, an induced voltage being generated in accordance with a rotation of the brushless motor; a rectifier circuit configured to rectify an AC voltage; a smoothing capacitor configured to smooth the AC voltage rectified by the rectifier circuit to a pulsation voltage having a maximum value larger than the induced voltage and a minimum value smaller than the induced voltage; and an inverter circuit configured to perform switching operations to output the pulsation voltage to the plurality of stator windings by rotation. - View Dependent Claims (2, 3)
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4. An electric power tool comprising:
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a brushless motor including;
a stator having a plurality of stator windings to which an AC voltage is applied from an AC power source; and
a rotor rotatable for the stator;an end tool that is driven in accordance with the rotation of the rotor; an inverter circuit configured to perform switching operations to output the pulsation voltage to the plurality of stator windings by rotation, even if the AC voltage is smaller than a preset voltage.
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5. An electric power tool comprising:
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a motor; a voltage supplying unit configured to supply a drive voltage to the motor; a current detecting circuit configured to detect a current flowing through the motor; and a control unit configured to control the voltage supplying unit to decrease the drive voltage when the current detected by the current detecting circuit is larger than a first current. - View Dependent Claims (6, 7, 8, 12)
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9. An electric power tool comprising:
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a motor; a voltage supplying unit configured to supply a drive voltage set to a target voltage to the motor; a rotational speed detecting circuit configured to detect a rotational speed of the motor; and a control unit configure to change the target voltage based on the rotational speed detected by the rotational speed detecting unit.
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10. An electric power tool comprising:
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a power cable connectable to an AC power source; a brushless motor that is rotated with a power supplied from the AC power source; an end tool that is driven in accordance with the rotation of the brushless motor; a current detecting circuit configured to detect a current flowing through the brushless motor; and a control unit configured to decrease a drive voltage of the brushless motor when the current detected by the current detecting circuit is larger than a preset current value. - View Dependent Claims (11)
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13. An electric power tool comprising:
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a power cable connectable to an AC power source; a brushless motor that is rotated with an AC power supplied from the AC power source, a pulsation current flowing through the brushless motor with the AC power; an end tool that is driven in accordance with the rotation of the brushless motor; a current detecting circuit configured to detect the pulsation current flowing through the brushless motor; and a restraining unit configured to retrain a peak of the pulsation current flowing through the brushless motor. - View Dependent Claims (14)
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15. An electric power tool comprising:
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a motor; a voltage supplying unit configured to generate a drive voltage from a DC voltage and supply the drive voltage to the motor; a voltage detecting circuit configured to detect the DC voltage; and a control unit configured to prohibit the voltage supplying unit from supplying the drive voltage to the motor when the DC voltage detected by the voltage detecting circuit is outside a preset range.
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16. An electric power tool comprising:
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a motor; a rectifier circuit configured to convert an AC voltage into a rectified voltage; a voltage supplying unit configured to generate a drive voltage from the rectified voltage and supply the drive voltage to the motor; a voltage detecting circuit configured to detect the rectified voltage; and a control unit configured to prohibit the voltage supplying unit from supplying the drive voltage to the motor when the rectified voltage detected by the voltage detecting circuit is outside a preset range. - View Dependent Claims (17)
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18. An electric power tool comprising:
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a power cable connectable to an AC power source; a voltage supplying unit configured to generate a drive voltage from the power supplied from the AC power source; a brushless motor that is rotated with the drive voltage; an end tool that is driven in accordance with the rotation of the brushless motor; a current detecting circuit configured to detect a current flowing through the brushless motor; and a control unit configured to perform a PWM control to control the voltage supplying unit, wherein the control unit determines a duty of the PWM control based on a difference between the current detected by the current detecting circuit and a first current value when the current detected by the current detecting circuit is larger than the first current value.
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19. An electric power tool comprising:
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a power cable connectable to an AC power source; a voltage supplying unit configured to generate a drive voltage from the power supplied from the AC power source; a brushless motor that is rotated with the drive voltage; an end tool that is driven in accordance with the rotation of the brushless motor; a current detecting circuit configured to detect a current flowing through the brushless motor; and a control unit configured to perform a PWM control to control the voltage supplying unit, wherein the control unit decreases a duty of the PWM control when the drive voltage is larger than a first voltage value.
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20. An electric power tool comprising:
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a power cable connectable to an AC power source; a voltage supplying unit configured to generate a drive voltage from the power supplied from the AC power source; a brushless motor that is rotated with the drive voltage; an end tool that is driven in accordance with the rotation of the brushless motor; a voltage detecting circuit configured to detect the drive voltage; and a control unit configured to perform a PWM control to control the voltage supplying unit, wherein the control unit determines a duty of the PWM control based on a difference between the voltage detected by the voltage detecting circuit and a first voltage value when the voltage detected by the voltage circuit is larger than the first voltage value.
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Specification