Electric tool

Patent metadata

Field	Value
Publication number	US-10759080-B2
Application number	US-201815863246-A
Country	US
Kind code	B2
Filing date	Jan 5, 2018
Priority date	Jan 22, 2017
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

An electric tool includes a functional piece, a motor, a case and a fan. The case includes a motor case portion. An airflow inlet and an airflow outlet are formed in the case. When the fan operates, an airflow at the airflow inlet is taken out and is directed to the airflow outlet after the airflow flows through the motor. The motor case portion includes an encircling portion which encircles the motor and an end portion arranged on one end of the encircling portion. The motor includes a stator, a motor shaft and a rotor. The stator is fixed relative to the case. The motor shaft is rotatably arranged in the case. The rotor surrounds the stator and rotates synchronously with the motor shaft. A stopping piece having a stopping portion is arranged at a first clearance between the rotor and the encircling portion. A projection of the stopping piece in a plane perpendicular to a rotating axis of the rotor is at least partially located outside a projection of the rotor in the plane. The stopping piece stops the airflow from flowing back from one side of the motor to the other side.

First claim

What is claimed is:

1. An electric tool, comprising:
a rotatable, working accessory;
a motor configured to drive the working accessory to rotate;
a case comprising a motor case portion for accommodating the motor and a main handle portion for gripping; and
a fan arranged on one side of the motor away from the working accessory;
wherein an airflow inlet and an airflow outlet are formed in the case whereby, when the fan operates, an airflow at the airflow inlet is taken out and is directed to the airflow outlet after the airflow flows through the motor, the motor case portion comprises an encircling portion which encircles the motor and an end portion arranged on one end of the encircling portion, and the case further comprises a coupling portion for coupling with a battery pack and a connecting portion for connecting the coupling portion and the motor case portion, and the airflow inlet is arranged at the connecting portion,
wherein the motor comprises a stator fixed relative to the case, a motor shaft arranged in the case rotatably about a motor axis, and a rotor which surrounds the stator and rotates synchronously with the motor shaft,
wherein the electric tool further comprises a stopping piece comprising a stopping portion arranged at a first clearance between the rotor and the encircling portion and a projection of the stopping piece in a plane perpendicular to a rotating axis of the rotor is at least partially located outside a projection of the rotor in the plane, and
wherein the fan is disposed at the rear side of the rotor, at least a portion of the stopping piece is disposed at the front side of the motor, the airflow passes through the inside of the rotor along a first direction from the front side of the motor to the rear side of the motor, and the stopping portion is arranged at the first clearance between the rotor and the encircling portion to stop the airflow from the fan from flowing back outside the rotor along a second direction opposite of the first direction.

2. The electric tool according to claim 1 , wherein the stopping piece forms a fixed connection with the stator.

3. The electric tool according to claim 1 , wherein the stopping portion encircles the rotor and
the stopping piece further comprises a first extending portion extending along a radial direction from the stopping portion to a direction away from the motor and extending to an outer side of the first clearance between the rotor and the encircling portion in the radial direction.

4. The electric tool according to claim 3 , wherein the stopping piece further comprises a second extending portion extending along the radial direction from the stopping portion to a direction close to the motor and extending to an outer side of the first clearance between the rotor and the encircling portion in the radial direction.

5. The electric tool according to claim 3 , wherein the stopping portion extends along a direction parallel to the rotating axis of the rotor, and a length of the stopping portion in the direction parallel to the rotating axis of the rotor is greater than a length of the first extending portion in the radial direction.

6. The electric tool according to claim 1 , wherein a second clearance is formed between the stopping portion and the encircling portion, and a maximum size of the second clearance between the stopping portion and the encircling portion in the radial direction is less than a minimum size of the first clearance between the rotor and the encircling portion in the radial direction.

7. The electric tool according to claim 1 , wherein the fan is a centrifugal fan.

8. The electric tool according to claim 1 , wherein the rotor is further formed with a vent hole located at one side of the stator close to the fan.

Assignees

• Nanjing Chervon Ind Co Ltd

Inventors

• Masatoshi Fukinuki
• Yang Xin
• Lu Bing
• Lu Songsong

Classifications

• B25F5/008 Primary

  Cooling means · CPC title

• B27B9/00

  Portable power-driven circular saws for manual operation (details or components, e.g. handles, casings, of portable power-driven tools not particularly related to the operation performed B25F5/00) · CPC title

• B27B9/02 Primary

  Arrangements for adjusting the cutting depth or the amount of tilting · CPC title

• B25F5/02

  Construction of casings, bodies or handles {(B25F5/006, B25F5/008 take precedence)} · CPC title