Electric power tool and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-10562115-B2
Application number	US-201715631949-A
Country	US
Kind code	B2
Filing date	Jun 23, 2017
Priority date	Jul 29, 2016
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

A covering member made of a resin is integrally molded with a sensor substrate of a brushless motor in a circular saw by low-temperature, low-pressure injection molding. The covering member covers rotation detecting elements, a thermistor, resistors, and connecting portions (terminals) of lead wires that serve as electrically conductive portions conducting electric currents.

First claim

What is claimed is:

1. An electric power tool comprising:
a stator including a stator core, an insulating member held by the stator core, and a coil held by the insulating member,
a rotor including a rotor core located inside the stator and a permanent magnet fixed to the rotor core,
a rotor shaft fixed to the rotor,
a rotation detecting element that detects a position of the permanent magnet,
a sensor substrate equipping the rotation detecting element, and
a thermoplastic resin having a softening point below 200° C. that covers the rotation detecting element and at least a part of the sensor substrate.

2. The electric power tool according to claim 1 , wherein
the sensor substrate has a hole through which the rotor shaft passes, and
the thermoplastic resin has an inner surface adjacent portion adjacent to an inner surface of the hole.

3. The electric power tool according to claim 1 , wherein
the sensor substrate has a mounting hole portion so that the sensor substrate is fixed to the insulating member, and
the mounting hole portions are not covered with the thermoplastic resin.

4. The electric power tool according to claim 1 , wherein
the sensor substrate has a connecting portion,
a lead wire is connected to the connecting portion, and
the thermoplastic resin covers the connecting portion and a part of the lead wire.

5. The electric power tool according to claim 4 , wherein
the sensor substrate has a first surface and a second surface, and
the rotation detecting element and the lead wire are connected to the first surface.

6. The electric power tool according to claim 5 , wherein
at least a part of the sensor substrate is not covered with the thermoplastic resin.

7. The electric power tool according to claim 5 , wherein
a plurality of transistors are connected to the second surface, and
the plurality of transistors is covered with thermoplastic resin.

8. The electric power tool according to claim 7 , wherein
a resistor and a thermistor are connected to the first surface, and
the resistor and the thermistor are covered with thermoplastic resin.

Assignees

• Makita Corp

Inventors

• Suzuki Ryosuke
• Niwa Akira

Classifications

• B23B45/008

  Gear boxes, clutches, bearings, feeding mechanisms or like equipment · CPC title

• B23D51/02

  of beds; of guiding arrangements for work-tables or saw carriers; of frames · CPC title

• B23B2260/128

  Sensors · CPC title

• B25F5/008

  Cooling means · CPC title

• B23D47/02 Primary

  of frames; of guiding arrangements for work-table or saw-carrier · CPC title