ELECTRICALLY POWERED TOOL

• US 20190358769A1
• Filed: 05/26/2017
• Published: 11/28/2019
• Est. Priority Date: 06/30/2016
• Status: Active Grant

• Current Assignee: Koki Holdings Co., Ltd.
• Original Assignee: Koki Holdings Co., Ltd.
• Inventors: MIYAZAWA, Ken, SAKAI, Hironori
• Granted Patent: US 11,986,924 B2
• Time in Patent Office: Days
• CPC Class Codes: B24B 23/02 with rotating grinding tools; Accessories therefor
• CPC Class Codes: B24B 47/12 by mechanical gearing or electric power B24B47/16 takes precedence
• CPC Class Codes: B25F 5/008 Cooling means
• CPC Class Codes: B25F 5/02 Construction of casings, bodies or handles B25F5/006, B25F5/008 take precedence

Abstract

Provided is an electrically powered tool configured so that a handle section is rotatable relative to a body section, wherein a motor housing is formed in a cylindrical integral structure, and a first drive circuit on which a switching element is mounted is received from a rear opening. The first drive circuit is disposed within a circular cylindrical case open to the rear side. A handle housing is provided with an air flow window, and a gear case is provided with a discharge opening. When a cooling fan rotates, air is sucked into the handle housing from the air flow window. Then, as indicated by the arrow, the air cools, within the motor housing, the switching element mounted on the first derive circuit, then cools the motor, and is discharged to the outside from the discharge opening.

Claims

1. An electrically powered tool comprising:

a cylindrical integral motor housing that accommodates and supports a brushless motor;

a cooling fan that is rotated by the brushless motor;

a spindle that is rotated by the brushless motor;

a power transmission mechanism configured to transmit a rotational force of the brushless motor to the spindle;

a gear case which is attached to an other side of the motor housing in an axial direction and in which the power transmission mechanism is accommodated;

a handle housing which is connected to one side of the motor housing and in which a grip section is formed; and

a drive circuit on which a switching element is mounted and which drives the brushless motor,

wherein an air flow window is provided in the handle housing and a discharge opening is provided in the gear case, and when the cooling fan rotates, air is sucked from the air flow window into the handle housing, the air passes through an inside of the motor housing and cools the drive circuit, and then cools the brushless motor, and is discharged from the discharge opening to an outside.

2. The electrically powered tool according to claim 1,

wherein the handle housing has a diameter-increased section that has a larger diameter than the grip section and is connected to the motor housing,

the diameter-increased section is positioned between the grip section and the motor housing, and

the air flow window is provided in the diameter-increased section.

3. The electrically powered tool according to claim 1,

wherein the drive circuit is mounted on a first circuit board that extends in a direction substantially perpendicular to a rotation axis of the brushless motor.

4. The electrically powered tool according to claim 3,

wherein the first circuit board is accommodated in a case having an opening and the opening faces an air intake side.

13. The electrically powered tool according to claim 1,

wherein the drive circuit is mounted on a first circuit board accommodated in the motor housing and further includes a second circuit board on which an operation unit configured to control the switching element is mounted, and

the first circuit board is disposed between the second circuit board and the brushless motor.

14. The electrically powered tool according to claim 13,

wherein the handle housing has a diameter-increased section which has a larger diameter than the grip section and is connected to the motor housing,

the diameter-increased section is positioned between the grip section and the motor housing,

the air flow window is provided in the diameter-increased section, and

the second circuit board is accommodated in the diameter-increased section.

15. The electrically powered tool according to claim 14,

wherein the handle housing is divisible and the second circuit board is clamped by the handle housing.

16. The electrically powered tool according to claim 15,

wherein the first circuit board and the second circuit board are disposed to extend in a direction substantially perpendicular to a rotation axis of the brushless motor.

17. The electrically powered tool according to claim 16,

wherein the air flow window is disposed between the first circuit board and the second circuit board.

18. The electrically powered tool according to claim 17,

wherein the handle housing accommodates a third circuit board on which a noise filter circuit is mounted, and

the second circuit board is disposed between the first circuit board and the third circuit board in rotating shaft direction.

19. The electrically powered tool according to claim 18,

wherein the handle housing has a rim part having a larger diameter than the grip section on the side of the grip section opposite to the diameter-increased section, and

the third circuit board is accommodated in the rim part.

20. The electrically powered tool according to claim 19,

wherein the diameter-increased section and the rim part gradually increase in diameter away from the grip section.

21. The electrically powered tool according to claim 20,

wherein the third circuit board includes a filter element that protrudes from a mounting surface, and

the third circuit board is inclined with respect to rotation axis and is accommodated so that a protrusion direction of the filter element and an extension direction of the grip section cross each other.

22. The electrically powered tool according to claim 21,

wherein a power cord for commercial AC power supply is provided in the rim part,

a switch configured to turn the brushless motor on and off by an operation thereof is provided in the grip section, and

in the rotational axis direction, from the rear side, the power cord, the third circuit board, the switch, the first circuit board, and the brushless motor are accommodated in this order and electrically connected in this order.

23. The electrically powered tool according to claim 22,

wherein a rectifier circuit configured to rectify power supplied from the power cord is provided, and

the rectifier circuit is mounted on the first circuit board and is electrically connected between the switch and the switching element.

5. (canceled)

6. (canceled)

7. (canceled)

8. (canceled)

9. (canceled)

10. (canceled)

11. (canceled)

12. (canceled)

24. (canceled)

25. (canceled)

26. (canceled)

27. (canceled)

28. (canceled)

29. (canceled)

30. (canceled)

31. (canceled)

32. (canceled)

33. (canceled)

34. (canceled)