Power tool

Patent metadata

Field	Value
Publication number	US-10875168-B2
Application number	US-201715724598-A
Country	US
Kind code	B2
Filing date	Oct 4, 2017
Priority date	Oct 7, 2016
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

A power tool contains a brushless motor that includes a stator having a stack thickness and an outer diameter, a rotor having a diameter, and a motor shaft extending from the rotor and having a rotational axis. A drive mechanism is operably coupled to the motor shaft and is configured to drive a tool accessory in relation to a drive axis. A first housing houses the motor and the drive mechanism. The drive axis does not intersect the brushless motor, but the rotational axis of the motor shaft intersects the drive axis. The outer diameter of the stator is at least five times greater than the stack thickness. Furthermore, the diameter of the rotor is greater than the stack thickness.

First claim

We claim:

1. A power tool configured to at least linearly reciprocally drive a tool accessory in relation to a drive axis that extends in a first direction, comprising:
a brushless motor comprising a stator having a stack thickness and an outer diameter, a rotor having a diameter and being disposed in an interior of the stator, and a motor shaft extending from the rotor and having a rotational axis;
a drive mechanism comprising a hammer element configured to at least linearly drive the tool accessory in the first direction by striking the tool accessory, and a crank mechanism configured to convert rotary motion of the motor shaft into linear motion and to transmit said linear motion to the hammer element;
a housing that houses the motor and the drive mechanism; and
a first battery-mounting part provided on the housing and configured to detachably mount a first rechargeable battery;
wherein:
the stator and rotor are spaced apart from the drive axis;
the rotational axis of the motor shaft extends in a second direction that intersects the drive axis and the first direction;
the first battery-mounting part includes a first means for physically engaging the first rechargeable battery and a second means for electrically connecting to the first rechargeable battery;
when viewed in a third direction that is perpendicular to both the first direction and the second direction, the brushless motor is interposed between the drive axis and at least one of the first means and the second means in a direction perpendicular to the first direction such that at least a portion of the brushless motor is aligned with at least a portion of the at least one of the first means and the second means in the second direction;
the outer diameter of the stator is at least five times greater than the stack thickness; and
the diameter of the rotor is greater than the stack thickness.

2. The power tool according to claim 1 , further comprising:
a fan that is rotated by the motor; and
a controller configured to control the operation of at least the brushless motor;

wherein:
the fan is configured to generate a cooling draft that flows in from a vent formed in the housing, passes along the controller, and then passes along the motor; and
when viewed in the third direction, the fan is interposed between the drive axis and the at least one the first means and the second means in the direction perpendicular to the first direction such that at least a portion of the fan is aligned with at least a portion of the at least one of the first means and the second means in the second direction.

3. The power tool according to claim 1 , further comprising:
a grasp part configured to be graspable by a user;
wherein:
the housing comprises a first housing part that houses the motor and the drive mechanism; and
the grasp part is coupled to, and is capable of moving relative to, the first housing part via an elastic element.

4. The power tool according to claim 3 , wherein:
the housing further comprises a second housing part that is coupled to, and is capable of sliding in parallel to the first direction relative to, the first housing part via the elastic element;
the second housing part includes the grasp part and a second portion that extends in the first direction; and
the first and second means are provided on the second portion of the second housing part such that, when viewed in the third direction, the second portion of the second housing part is interposed between the stator and the first and second means in the direction perpendicular to the first direction.

5. The power tool according to claim 1 , further comprising:
a controller housed in the housing and configured to control operation of at least the brushless motor;
wherein the controller, when viewed in the third direction, is at least partially interposed between the brushless motor and the at least one of the first and second means in the direction perpendicular to the first direction such that at least a portion of the brushless motor is aligned with at least a portion of the controller in the second direction.

6. A power tool, comprising:
a brushless motor comprising a stator having a stack thickness and an outer diameter, a rotor having a diameter and being disposed in an interior of the stator, and a motor shaft extending from the rotor and having a rotational axis;
a drive mechanism comprising a striker and an impact bolt configured to at least linearly reciprocally drive a tool accessory along a drive axis that extends in a first direction by the impact bolt striking the tool accessory, and a crank mechanism configured to convert rotary motion of the motor shaft into linear motion and to transmit said linear motion to a piston that is slidably disposed in a cylinder and is configured to linearly drive the striker in the cylinder along the drive axis;
a first housing that houses the motor and the drive mechanism; and
a first battery-mounting part having battery-connection terminals provided on a second housing and configured to detachably mount a first rechargeable battery;
wherein:
the drive axis does not intersect the stator, the rotor or the motor shaft;
the rotational axis of the motor shaft intersects the first direction;
when viewed in a lateral direction that is perpendicular to both the first direction and the rotational axis, the brushless motor is interposed between the drive axis and the battery-connection terminals in a direction perpendicular to the first direction such that the at least a portion of the brushless motor is aligned with at least a portion of the battery-connection terminals in the direction perpendicular to the first direction;
the outer diameter of the stator is at least five times greater than the stack thickness; and
the diameter of the rotor is greater than the stack thickness.

7. The power tool according to claim 6 , wherein the drive mechanism further comprises a plurality of gears configured to transmit the rotary motion of the motor shaft to the tool accessory to thereby rotate the tool accessory.

8. The power tool according to claim 7 , further comprising:
a fan operably coupled to the motor shaft; and
a controller configured to control the operation of at least the brushless motor;
wherein the fan and the first housing are configured to generate a cooling draft that flows in from a vent formed in the first housing, passes along the controller, and then passes along the motor; and
when viewed in the lateral direction, the fan is interposed between the drive axis and the battery-connection terminals in the direction perpendicular to the first direction such that at least a portion of the fan is aligned with at least a portion of the battery-connection terminals in the direction perpendicular to the first direction.

9. The power tool according to claim 8 , wherein:
the controller is disposed in the second housing; and
when viewed in the lateral direction, at least a portion of the brushless motor is aligned with at least a portion of the controller in the direction perpendicular to the first direction.

10. The power tool according to claim 9 , further comprising:
a handle is coupled to, and capable of moving relative to, the first housing via at least one elastic element.

11. The power tool according to claim 10 , wherein:
the second housing is coupled to, and is slidable in parallel to the first direction relative to, the first housing via the elastic element; and
the second housing includes the handle.

12. The power tool according to claim 11 , wherein:
the outer diameter of the stator is at least seven times greater than the stack thickness.

Assignees

• Makita Corp

Inventors

• Iida Hitoshi
• Furusawa Masanori

Classifications

• B25D11/00

  Portable percussive tools with electromotor {or other motor} drive · CPC title

• B25D2211/003

  Crossed drill and motor spindles · CPC title

• B25D2216/0015

  Tools having a percussion-only mode · CPC title

• B25D17/043

  Handles resiliently mounted relative to the hammer housing (B25D17/046 takes precedence) · CPC title

• B25D2216/0038

  Tools having a rotation-only mode · CPC title