Power tool

Patent metadata

Field	Value
Publication number	US-11141804-B2
Application number	US-201716463808-A
Country	US
Kind code	B2
Filing date	Oct 27, 2017
Priority date	Nov 30, 2016
Publication date	Oct 12, 2021
Grant date	Oct 12, 2021

Abstract

A power tool includes a motor; a fan configured to be rotated by the motor to generate a cooling air; a housing accommodating therein the motor and the fan and defusing an air passage for the cooling air; an output shaft rotatable by the motor; and a transmission mechanism configured to transmit rotation of the motor to the output shaft. An end bit being attachable to and detachable from the output shaft. The transmission mechanism includes an intermediate shaft provided in the housing, a first belt transmitting a rotational force of the motor to the intermediate shaft, a second belt transmitting a rotational force of the intermediate shaft to the output shaft, and a rotation member transmitting a rotational force of the second belt to the output shaft. The first belt and the second belt are positioned inside a space through which the cooling air passes.

First claim

The invention claimed is:

1. A power tool comprising:
a motor;
a fan configured to be rotated by the motor to generate a cooling air;
a housing accommodating therein the motor and the fan and defining an air passage for the cooling air;
an output shaft rotatable by the motor, an end bit being attachable to and detachable from the output shaft; and
a transmission mechanism configured to transmit rotation of the motor to the output shaft; and
a bearing,
wherein the transmission mechanism comprises an intermediate shaft provided in the housing and supported by the bearing, a first belt transmitting a rotational force of the motor to the intermediate shaft, a second belt transmitting a rotational force of the intermediate shaft to the output shaft, and a rotation member transmitting a rotational force of the second belt to the output shaft, and
wherein the housing comprises:
a motor accommodating portion accommodating the motor;
a first belt accommodating portion accommodating the first belt, the first belt accommodating portion being in communication with the motor accommodating portion;
a second belt accommodating portion accommodating the second belt, the second belt accommodating portion being in communication with the first belt accommodating portion;
a communicating space formed at a position outward of the bearing in a radial direction of the bearing, the communicating space being in communication with the first and second belt accommodating portions; and
an airflow passage that directs the cooling air from an intake port, through the motor accommodating portion, the first belt accommodating portion, the communicating space, and the second belt accommodating portion, to an outlet port.

2. The power tool according to claim 1 ,
wherein the housing comprises a case accommodating therein the rotation member,
wherein the case has a port through which the cooling air is drawn into the case, and the outlet port through which the cooling air is discharged outside the case, and
wherein the case provides a space between the port and the outlet port, and the air passage includes the space where the rotation member is positioned.

3. The power tool according to claim 2 , wherein the rotation member is a pulley.

4. The power tool according to claim 3 , wherein the transmission mechanism further comprises a first pulley configured to rotate in synchronization with the motor a second pulley and a third pulley, each of the second pulley and the third pulley being rotatable about an axis of the intermediate shaft,
wherein the first belt is looped over the first pulley and the second pulley, and the second belt is looped over the third pulley and the pulley, and
wherein the first pulley, the second pulley, and the third pulley are positioned inside the space through which the cooling air passes.

5. The power tool according to claim 2 ,
wherein a working space is defined between the case and a workpiece to be machined by the end bit,
wherein the outlet port is positioned in the case to face at least one of the end bit and the working space, and
wherein the cooling air is discharged toward the end bit or the working space.

6. The power tool according to claim 2 ,
wherein the intake port is open to a space in the housing,
wherein the housing has an air introduction opening,
wherein the air passage is in communication with the air introduction opening and extends to the outlet port through the intake port, and
wherein the air introduction opening is positioned opposite to the outlet port with respect to the output shaft.

7. The power tool according to claim 2 , wherein the intake port and the outlet port are positioned remote from each other in a direction parallel to or orthogonal to a rotation axis of the rotation member, and
wherein the rotation member is positioned between the outlet port and the intake port.

8. The power tool according to claim 1 , wherein the rotation member further comprises a bearing rotatably supporting the output shaft.

9. The power tool according to claim 1 ,
wherein the housing further comprises a second belt accommodating portion accommodating the second belt, the second belt accommodating portion having an air hole, and
wherein the communicating space and the air hole are positioned remote from each other in an axial direction of the output shaft.

10. The power tool according to claim 1 , wherein the cooling air passes through the communicating space after passing through the airflow passage.

11. The power tool according to claim 1 , wherein the second belt is positioned between the first belt and the end bit in an axial direction of the output shaft.

12. The power tool according to claim 1 ,
wherein the transmission mechanism further comprises a first pulley configured to rotate in synchronization with the motor, a second pulley, and a third pulley, each of the second pulley and the third pulley being rotatable about an axis of the intermediate shaft,
wherein the rotation member is a pulley,
wherein the first belt is looped over the first pulley and the second pulley, and the second belt is looped over the third pulley and the pulley, and
wherein the bearing is positioned between the second pulley and the third pulley in an axial direction of the output shaft.

Assignees

• Koki Holdings Co Ltd

Inventors

• Toyoshima Yuuichi
• Kumakura Takeru
• Sekine Yoshitaka

Classifications

• B25F5/008 Primary

  Cooling means · CPC title

• B23D45/048

  the saw blade being adjustable according to angle of cut · CPC title

• B23D47/12

  of drives for circular saw blades · CPC title

• B27B5/20

  the saw blade being adjustable according to depth or angle of cut; Radial saws, i.e. sawing machines with a pivoted radial arm for guiding the movable carriage · CPC title

• B23D45/044 Primary

  the saw blade being adjustable according to angle of cut (B23D45/025 takes precedence) · CPC title