Screw-tightening power tool
A screw-tightening power tool includes a motor housing. A brushless motor has a stator that is fixed to the motor housing and a rotor that is rotatable relative to the stator. A tip-tool retaining part is configured to hold a bit and a clutch is disposed between the rotor and the tip-tool retaining part. A grip housing extends from the motor housing. A switch assembly is provided in the grip housing and a trigger is held by the switch assembly. A sensor-circuit board is fixed to the stator. The sensor-circuit board and the switch assembly are connected by a first cord, and the stator and the switch assembly are connected by a second cord.
1. A screw-tightening power tool, comprising:
a motor housing;
a grip housing downwardly extending from a lower part of the motor housing;
a brushless motor comprising: a stator fixed to the motor housing and a rotor that is rotatable relative to the stator, a rotary shaft being attached to the rotor;
a tip-tool retaining part configured to hold a bit;
a clutch disposed between the rotor and the tip-tool retaining part in an axial direction of the power tool, the clutch comprising a cam releasably meshing with a cam part;
a cooling fan disposed between the stator and the clutch in the axial direction;
a battery mounting part disposed at a lower part of the grip housing;
a battery pack detachably affixed to the battery mounting part;
an LED located on an upper portion of the battery mounting part;
a trigger that protrudes from the grip housing;
a trigger switch disposed within the grip housing;
a pinion securely mounted to a front end of the rotary shaft and directly meshing with an integrated gear fixed to a first spindle; and
a coil spring interposed between the cam and the cam part;
wherein the clutch has a rotational axis,
a rotational axis of the rotary shaft is disposed between the rotational axis of the clutch and the lower part of the grip housing in a direction perpendicular to the axial direction, and
the rotational axis of the rotary shaft extends in parallel to the rotational axis of the clutch.
2. The screw-tightening power tool according to claim 1 , wherein:
a trigger switch assembly that includes the trigger switch is provided in the grip housing;
the trigger is held by the trigger switch assembly;
a sensor-circuit board is fixed to the stator;
the sensor-circuit board and the trigger switch assembly are connected by a first cord; and
the stator and the trigger switch assembly are electrically connected by a second cord.
3. The screw-tightening power tool according to claim 2 , wherein the LED is configured to provide illumination and is connected to the switch assembly by a third cord.
4. The screw-tightening power tool according to claim 2 , wherein the second cord is configured to supply electrical current to a coil of the brushless motor and is connected via an insulating member provided on the stator.
5. The screw-tightening power tool according to claim 1 , wherein a sensor-circuit board is located on a rear side of the rotor in the axial direction and the clutch is disposed forward of the rotor in the axial direction.
6. The screw-tightening power tool according to claim 2 , wherein a control circuit board is provided integrally with a lower part of the trigger to form the trigger switch assembly.
7. The screw-tightening power tool according to claim 1 , further comprising a control circuit board disposed in the motor housing between the motor and a lower part of the motor housing in the direction perpendicular to the axial direction, the control circuit board being equipped with an Intelligent Power Module, a microcontroller and capacitors.
8. The screw-tightening power tool according to claim 7 , wherein the Intelligent Power Module contains switching devices and a driver for driving the switching devices.
9. The screw-tightening power tool according to claim 1 , wherein the LED faces diagonally from the upper portion of the battery mounting part toward the tip-tool retaining part.
10. The screw-tightening power tool according to claim 1 , wherein:
the tip-tool retaining part comprises a second spindle that is coaxially disposed forward of the first spindle such that it is capable of forward-rearward movement,
a mount hole configured to receive the bit is defined at a front end of the second spindle, and
the cam part is defined at a rear end of the second spindle.
11. The screw-tightening power tool according to claim 10 , wherein a sensor-circuit board is located on a rear side of the rotor in the axial direction and the clutch is disposed forward of the rotor in the axial direction.
12. The screw-tightening power tool according to claim 11 , wherein a control circuit board is provided integrally with a lower part of the trigger to form a trigger switch assembly.
13. The screw-tightening power tool according to claim 1 , further comprising a terminal block disposed in the battery mounting part, the terminal block being configured to electrically connect to the battery pack.
14. The screw-tightening power tool according to claim 12 , wherein the control circuit board is equipped with a microcontroller, capacitors, switching devices electrically connected to coils on the stator, and a driver that drives the switching devices.
15. The screw-tightening power tool according to claim 1 , wherein the first spindle is a part of the clutch.
16. A screw-tightening power tool comprising:
a motor housing;
a brushless motor in the motor housing, the brushless motor comprising a stator and a rotor rotatably mounted relative to the stator;
a grip housing downwardly extending from a lower part of the motor housing;
a cooling fan disposed frontward of the rotor;
a battery mounting part disposed at a lower part of the grip housing;
a rotary shaft affixed to the rotor and extending in a front-rear direction;
a pinion located frontward of the cooling fan and securely mounted to the rotary shaft;
a gear meshed with the pinion and connected to a first cam;
a second cam disposed frontward of the first cam and shiftable in the front-rear direction from a first position spaced from the first cam to a second position meshed with the first cam;
a tip-tool retaining part operably connected to the second cam and configured to hold a bit;
a coil spring biasing the second cam away from the first cam;
an LED located on an upper portion of the battery mounting part, the LED facing diagonally upward and configured to illuminate an area frontward of the bit;
a trigger switch disposed within the grip housing; and
a control circuit board configured to control the brushless motor, the control circuit board being disposed within the grip housing below the trigger switch and extending in an up-down direction.
17. The screw-tightening power tool according to claim 16 , wherein:
the stator includes a coil and an insulation member having a connecting piece,
the connecting piece is disposed above the rotor, and
the connecting piece connects the coil to a power cord.
18. The screw-tightening power tool according to claim 17 , wherein the power cord passes behind a rear end of the rotary shaft.
19. The screw-tightening power tool according to claim 16 , further comprising:
a sensor circuit board disposed rearward of the stator, the sensor circuit board being connected with the control circuit board by a first cord,
wherein a power cord passes behind a rear end of the rotary shaft.
20. The screw-tightening power tool according to claim 16 , further comprising an operation panel disposed rearward of the LED.
21. The screw-tightening power tool according to claim 16 , further comprising another cord that connects the LED to a lower part of the control circuit board.
22. The screw-tightening power tool according to claim 18 , further comprising:
a sensor circuit board disposed rearward of the stator, the sensor circuit board being connected with the control circuit board by a first cord,
an operation panel disposed rearward of the LED, and
another cord that connects the LED to a lower part of the control circuit board.