US 12,438,494 B2
Power tool
Guang Li, Nanjing (CN)
Assigned to Nanjing Chervon Industry Co., Ltd., Nanjing (CN)
Filed by Nanjing Chervon Industry Co., Ltd., Nanjing (CN)
Filed on Mar. 16, 2022, as Appl. No. 17/695,925.
Claims priority of application No. 202110371026.7 (CN), filed on Apr. 7, 2021.
Prior Publication US 2022/0329197 A1, Oct. 13, 2022
Int. Cl. H02H 1/06 (2006.01); H02K 7/14 (2006.01); H02K 11/33 (2016.01); H02M 1/32 (2007.01); H02P 25/03 (2016.01); H02P 27/08 (2006.01); H02P 29/68 (2016.01)
CPC H02P 29/68 (2016.02) [H02K 7/145 (2013.01); H02K 11/33 (2016.01); H02P 25/03 (2016.02); H02P 27/08 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A power tool, comprising:
a motor comprising a multi-phase winding;
a power supply configured to power the motor;
a switch configured to switch a power on-off state of the power tool;
a driver circuit comprising a plurality of power elements and configured to change a rotational state of the motor;
an operating element operable by a user having a first operating state and a second operating state, wherein a strength of an effective magnetic field of the multi-phase winding when the operating element is in the first operating state is less than a strength of an effective magnetic field of the multi-phase winding when the operating element is in the second operating state; and
a controller connected to the motor and configured to control the rotational state of the motor,
wherein the controller is configured to control conduction manners of the plurality of power elements in the driver circuit according to an operating state of the operating element, so as to adjust the strength of the effective magnetic field of the multi-phase winding to change the rotational state of the motor,
a rotational speed of the motor when the operating element is in the first operating state is greater than a rotational speed of the motor when the operating element is in the second operating state,
wherein the first operating state is a boost state, the second operating state is a normal state, the operating element comprises a boost key, and the boost key is configured to be operated by the user to switch the power tool between the normal state and the boost state, and
wherein the motor is in a first working state and has a maximum rotational speed when the operating element is in the first operating state and the motor is in a second working state and has a rotational speed less than the maximum rotational speed when the operating element is in the second operating state, a temperature threshold of over-temperature protection of the motor in the first working state is T1, a temperature threshold of over-temperature protection of the motor in the second working state is T2, and T2>T1.