IP Library Granted Patent US 12,472,564
Granted Patent B2
US 12,472,564 · App. 18/746,120 · Granted Nov 18, 2025

Core drill

Inventor: Tomohiko Imae (Anjo, JP)
Assignee: MAKITA CORPORATION
B23B45/008B23B45/02
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Quick Facts
Patent No.
US 12,472,564
App. No.
18/746,120
Granted
Nov 18, 2025
Kind
B2
Abstract

A core drill includes: a motor having a stator and a rotor, which is rotatable relative to the stator; a speed-reducing mechanism; an output shaft that, in the state in which a core bit is mounted thereon, is rotated by the rotational force of the rotor transmitted via the speed-reducing mechanism; and a battery-mounting part, on which a battery pack is mounted. A stator outer diameter, which is the outer diameter of a stator core of the stator, is 75 mm or more; and a stator length, which is the dimension of the stator core in an axial direction, is 30 mm or more.

Claims (67)

1 . A core drill comprising:

a motor comprising a stator and a rotor, which is rotatable relative to the stator;

a speed-reducing mechanism;

an output shaft that, in the state in which a core bit is mounted thereon, is rotated by the rotational force of the rotor transmitted via the speed-reducing mechanism; and

at least a first battery-mounting part, on which a first battery pack is mountable;

wherein:

a stator outer diameter, which is the outer diameter of a stator core of the stator, is 75 mm or more;

a stator length, which is the dimension of the stator core in an axial direction, is 30 mm or more; and

the core bit has a hole-drilling diameter, which is the outer diameter of a tip portion of the core bit, that is 155 mm or more.

2 . The core drill according to claim 1 , wherein the stator outer diameter is 120 mm or less.

3 . The core drill according to claim 2 , wherein:

the stator length is 65 mm or less;

the speed-reducing mechanism has a speed-reduction ratio of 1/16 to 1/5;

the motor has a rated output of 1,800-3,000 W.

4 . The core drill according to claim 3 , further comprising:

a second battery-mounting part electrically connected in series to the first battery-mounting part, on which a second battery pack is mountable;

wherein each of the first and second battery packs has a rated voltage of 40 V or more.

5 . The core drill according to claim 1 , wherein the stator length is 65 mm or less.

6 . The core drill according to claim 1 , wherein the hole-drilling diameter is 200 mm or less.

7 . The core drill according to claim 1 , wherein the speed-reducing mechanism has a speed-reduction ratio of 1/16 or more and 1/5 or less.

8 . The core drill according to claim 1 , wherein the motor has a rated output of 1,800 W or more and 3,000 W or less.

9 . The core drill according to claim 1 , wherein the at least first battery pack has a rated voltage of 80 V or more.

10 . The core drill according to claim 1 , further comprising:

a second battery-mounting part electrically connected in series to the first battery-mounting part, on which a second battery pack is mountable;

wherein each of the first and second battery packs has a rated voltage of 40 V or more.

11 . A core drill comprising:

a motor comprising a stator and a rotor, which is rotatable relative to the stator;

a motor-housing part that houses the motor;

a speed-reducing mechanism disposed more forward than the stator;

an output shaft that, in the state in which a core bit is mounted thereon, is rotated by the rotational force of the rotor transmitted via the speed-reducing mechanism;

a grip part configured to be gripped by a user, the grip part being disposed more rearward than the motor-housing part;

a trigger lever configured to control operation of the motor, the trigger lever being disposed on the grip part;

a first battery-mounting part, on which a first battery pack is mountable; and

a second battery-mounting part, which is connected in series to the first battery-mounting part and on which a second battery pack is mountable;

wherein:

at least a portion of the output shaft is disposed more forward than the speed-reducing mechanism; and

the first battery-mounting part and the second battery-mounting part are disposed more forward than the trigger lever.

12 . The core drill according to claim 11 , wherein:

a battery-connection part is disposed on the lower side of the motor-housing part; and

the first battery-mounting part and the second battery-mounting part are disposed on the battery-connection part.

13 . The core drill according to claim 11 , wherein:

a battery-connection part is disposed on a lower side of the motor-housing part;

the first battery-mounting part is disposed on the battery-connection part; and

the second battery-mounting part is disposed in the motor-housing part.

14 . The core drill according to claim 13 , wherein the second battery-mounting part is disposed on an upper portion of the motor-housing part.

15 . The core drill according to claim 11 , wherein:

a battery-connection part is disposed on a lower side of the motor-housing part; and

the first battery-mounting part and the second battery-mounting part are both disposed on the motor-housing part.

16 . The core drill according to claim 15 , wherein:

the first battery-mounting part is disposed on a left portion of the motor-housing part; and

the second battery-mounting part is disposed on a right portion of the motor-housing part.

17 . The core drill according to claim 11 , wherein:

a controller is disposed more rearward than the motor and controls the motor;

a controller-housing part is disposed between the motor-housing part and the grip part, the controller-housing part housing the controller;

the first battery-mounting part is disposed on the controller-housing part; and

the second battery-mounting part is disposed on the motor-housing part.

18 . The core drill according to claim 11 , wherein each of the first battery pack and the second battery pack has a rated voltage of 40 V or more.

19 . The core drill according to claim 11 , wherein the second battery-mounting part is disposed on an upper portion of the motor-housing part.

20 . A core drill comprising:

a motor comprising a stator and a rotor, which is rotatable relative to the stator;

a speed-reducing mechanism;

an output shaft configured to be rotated by the rotational force of the rotor transmitted via the speed-reducing mechanism;

a core bit that is mountable on the output shaft, the core bit having a hole-drilling diameter, which is the outer diameter of a tip portion of the core bit, that is 155 mm or more; and

at least a first battery-mounting part, on which a first battery pack is mountable;

wherein:

a stator core of the stator has an outer diameter that is 75 mm or more; and

the stator core has a length in an axial direction that is 30 mm or more.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 18, 2024
From: IMAE, TOMOHIKO
To: MAKITA CORPORATION
Reel/Frame 067751/0846 →
Priority Claims (3)
JP 2023-109190 · Jul 3, 2023 · national
JP 2023-109203 · Jul 3, 2023 · national
JP 2023-109204 · Jul 3, 2023 · national
Continuity (1)
Related Publication 20250010380A1 · Jan 9, 2025
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