公开(公告)号：US20240364097A1

公开(公告)日：2024-10-31

申请号：US18637892

申请日：2024-04-17

Applicant: MAKITA CORPORATION

Inventor： Kazuaki USAMI ,  Masayuki OKAMURA ,  Dai SUZUKI ,  Kouichi TAKEDA

IPC: H02H7/085 ,  A01G3/08 ,  B27B17/02 ,  B27B17/08

CPC classification number: H02H7/085 ,  B27B17/08 ,  A01G3/086 ,  B27B17/02

Abstract: An electric work machine according to the present disclosure includes: a motor; and a first control circuit. The first control circuit increases a first counter on the basis of the acquired or estimated line current value being greater than a current threshold. The first control circuit decreases the first counter on the basis of the calculated rotational speed being greater than a speed threshold. The first control circuit stops the motor on the basis of the first counter exceeding a first threshold.

公开(公告)号：US20230115229A1

公开(公告)日：2023-04-13

申请号：US17960530

申请日：2022-10-05

Applicant: MAKITA CORPORATION

Inventor： Masayuki OKAMURA ,  Kazuya OKUMA

IPC: A01D34/78

Abstract: An electric work machine includes a first and second motors; a first and second switches disposed on corresponding current conduction path from a direct-current power source to each motor; a first and second carrier frequency setting devices; and a controller. The first and second carrier frequency setting devices respectively set a first and second carrier frequencies of a time when PWM controlling an electric power supply to the first and second motors. The first and second carrier frequencies are different from each other. The controller drives the first switch or the second switch by using a PWM signal generated at the first or second carrier frequency and PWM controls an electric power supply to the first or second motor.

公开(公告)号：US20230336105A1

公开(公告)日：2023-10-19

申请号：US18134309

申请日：2023-04-13

Applicant: MAKITA CORPORATION

Inventor： Dai SUZUKI ,  Masayuki OKAMURA ,  Itsuku KATO

IPC: H02P29/032 ,  B25F5/00 ,  H02P6/24

CPC classification number: H02P29/032 ,  B25F5/00 ,  H02P6/24

Abstract: An electric working machine in one aspect of the present disclosure calculates an estimated heat value based on an electric current value and a parameter. The estimated heat value corresponds to an estimated heat generation amount of a motor. The electric current value corresponds to a magnitude of an electric current delivered from a power source to the motor. The electric work machine varies the parameter based on a load time. The load time corresponds to a time period during which a first load is continuously imposed on the motor. The first load has a specified magnitude or more. The electric work machine performs a protective operation for over temperature protection of the motor based on the estimated heat value having reached a heat threshold.

公开(公告)号：US20220371112A1

公开(公告)日：2022-11-24

申请号：US17751091

申请日：2022-05-23

Applicant: MAKITA CORPORATION

Inventor： Masayuki OKAMURA ,  Takuya KUSAKAWA ,  Itsuku KATO

IPC: B23D49/00

Abstract: An electric work machine in one aspect of the present disclosure includes a motor, a manual switch, and a control circuit. The control circuit switches a preset control either to be enabled or disabled. During the preset control being enabled, the control circuit (i) varies an actual rotational speed of the motor in accordance with an actual moved distance of the manual switch and (ii) increases the actual rotational speed in response to a load being imposed on the motor. During the preset control being disabled, the control circuit varies the actual rotational speed in accordance with the actual moved distance of the manual switch in a manner at least partly distinctive from a variation in the actual rotational speed during the preset control being enabled.