IP Library Granted Patent US 10,348,227
Granted Patent B2
US 10,348,227 · App. 15/278,523 · Granted Jul 9, 2019

Electric power tool

Inventor: Yoshitaka Ichikawa (Anjo, JP)
Assignee: MAKITA CORPORATION
H02P6/24B25F5/00H02K11/215H02P23/20H02P27/08H02P29/0241
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Quick Facts
Patent No.
US 10,348,227
App. No.
15/278,523
Granted
Jul 9, 2019
Kind
B2
Abstract

One aspect of the present disclosure relates to an electric power tool including a motor, an operation unit, a bridge circuit, and a control unit. The control unit performs a brake control when the motor is braked, and performs a regenerative current inhibition control before stopping the brake control when a drive command is inputted to the operation unit while the brake control is performed.

Claims (25)

1. An electric power tool comprising:

a motor;

an operation unit comprising a trigger that initiates a drive command for driving the motor;

a bridge circuit comprising a plurality of switching elements, the bridge circuit being configured to switch current flow paths to the motor by the plurality of switching elements each of the plurality of switching elements including a diode coupled thereto in parallel; and

a control unit configured to control the plurality of switching elements in the bridge circuit according to the drive command inputted to the operation unit, to thereby control driving of the motor, the control unit being further configured to perform a brake control when the motor is braked, and the control unit being further configured to perform, in response to the drive command inputted to the operation unit during the brake control being performed, a regenerative current inhibition control to thereafter stop the brake control, the brake control being set to turn on at least part of the plurality of switching elements in the bridge circuit to generate a braking force on the motor, and the regenerative current inhibition control being set to turn off each of all switching elements that are on, from among the plurality of switching elements in the bridge circuit, at given individual timings to inhibit a regenerative current from flowing in a power source of the motor, each of the given individual timings being a timing that allows a brake current to flow via the diode of each corresponding one of all the switching elements that are on in the bridge circuit.

2. The electric power tool according to claim 1 , wherein the regenerative current inhibition control is set to continue the brake control until a given timing when no further regenerative current flows in the power source of the motor via the bridge circuit.

3. The electric power tool according to claim 1 , wherein the regenerative current inhibition control is set to reduce a brake current flowing in the motor by switching control methods of the brake control.

4. The electric power tool according to claim 1 ,

wherein the motor comprises windings of a plurality of phases,

wherein the brake control is set to control the plurality of switching elements in the bridge circuit to generate the braking force by short-circuiting at least two phases out of the windings of the plurality of phases, and

wherein the regenerative current inhibition control is set to reduce phases short-circuited in the brake control.

5. The electric power tool according to claim 4 ,

wherein the windings of the plurality of phases comprise windings of three phases,

wherein the brake control is set to perform three-phase short-circuit braking that short-circuits the three phases, and

wherein the regenerative current inhibition control is set to perform two-phase short-circuit braking that short-circuits two phases of the three phases.

6. The electric power tool according to claim 5 ,

wherein the brake control is set to perform two-phase short-circuit braking that short-circuits two phases out of the plurality of phases, and

wherein the regenerative current inhibition control is set to perform one-phase short-circuit braking that short-circuits one phase of the two phases.

7. The electric power tool according to claim 5 ,

wherein the brake control is set to perform two-phase short-circuit braking that short-circuits two phases out of the plurality of phases, and

wherein the regenerative current inhibition control is set to perform one-phase short-circuit braking that short-circuits one phase of the two phases.

8. The electric power tool according to claim 1 , wherein the control unit is configured

(i) to perform the brake control at least when the drive command is not inputted thereto from the operation unit,

(ii) to control the plurality of switching elements in the bridge circuit to reduce a brake current flowing in the motor in the regenerative current inhibition control, and

(iii) to start driving the motor without performing the regenerative current inhibition control in response to the drive command inputted to the operation unit under a situation where the control unit is not performing the brake control.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 28, 2016
From: ICHIKAWA, YOSHITAKA
To: MAKITA CORPORATION
Reel/Frame 039876/0961 →
Priority Claims (1)
JP 2015-193777 · Sep 30, 2015 · national
Continuity (1)
Related Publication 20170093315A1 · Mar 30, 2017
Cited By (2)
US 12,323,084 US 12,556,113