POWER TOOLS

• US 20140374131A1
• Filed: 05/10/2012
• Published: 12/25/2014
• Est. Priority Date: 06/02/2011
• Status: Active Grant

• Current Assignee: Makita Corporation
• Original Assignee: Makita Corporation
• Inventors: Hirabayashi, Shinji, Matsuno, Tadasuke
• Granted Patent: US 9,469,023 B2
• Time in Patent Office: Days
• US Class Current: 173/181
• CPC Class Codes: B23B 45/02 driven by electric power
• CPC Class Codes: B25B 21/00 Portable power-driven screw or nut setting or loosening tools; details or components, e.g. casings, bodies, of portable power-driven tools not particularly related to the operation performed B25F5/00; for mounting or dismounting wheels B60B29/006; Attachments for drilling apparatus serving the same purpose machines B23P19/06
• CPC Class Codes: B25B 21/008 with automatic change-over from high speed-low torque mode to low speed-high torque mode
• CPC Class Codes: B25B 23/14 Arrangement of torque limiters or torque indicators in wrenches or screwdrivers couplings for transmitting rotation or clutches F16D; devices for measuring torque per se G01L
• CPC Class Codes: B25B 23/147 specially adapted for electrically operated wrenches or screwdrivers
• CPC Class Codes: B25F 5/00 Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
• CPC Class Codes: B25F 5/001 Gearings, speed selectors, clutches or the like specially adapted for rotary tools
• CPC Class Codes: F16H 15/52 in which a member of uniform effective diameter mounted on a shaft may co-operate with different parts of another member
• CPC Class Codes: H02P 25/145 whereby the speed is regulated by measuring the motor speed and comparing it with a given physical value, speed feedback

Abstract

A power tool has a continuously variable transmission, a condition detection device, and an operation control device. The continuously variable transmission changes a velocity of a rotational output from a drive motor and outputs the rotational output to a spindle to which a tip end tool is mounted. The condition detection device detects a condition of the power tool. The operation control device determines a target RPM of the spindle based on the condition of the power tool detected by the condition detection device, and controls an RPM of the drive motor and/or a transmission gear ratio of the continuously variable transmission based on the target RPM.

Claims

1. A power tool comprising:

a continuously variable transmission configured to change a velocity of a rotational output from a drive motor and to output the rotational output to a spindle to which a tip end tool is mounted;

a condition detection device is configured to detect a condition of the power tool; and

an operation control device configured to determine a target RPM of the spindle based on the condition of the power tool detected by the condition detection device, and to control an RPM of the drive motor and/or a transmission gear ratio of the continuously variable transmission based on the target RPM.

2. The power tool of claim 1, wherein the power tool comprises a plurality of different condition detection devices.

3. The power tool of claim 2, wherein as the plurality of different condition detection devices, the power tool comprises a device configured to detect an operational condition of a user, and a device configured to detect a condition of a tool main body which changes with an operation by the user, and

wherein the operation control device is configured to control the RPM of the drive motor and/or the transmission gear ratio of the continuously variable transmission based on the operational condition of the user, and control a condition of the tool main body to a predetermined optimum state.

4. The power tool of claim 2, wherein as the plurality of different condition detection devices, the power tool comprises at least two of the following condition detection devices:

a first condition detection device J1 configured to detect an operational condition of the operation member for starting the drive motor, a second condition detection device J2 configured to detect an electric current value, a third condition detection device J3 configured to detect temperature, a fourth condition detection device J4 configured to detect a stress condition of a drive transmission system, and a fifth condition detection device J5 configured to detect changes with passage of time in any of the first to fourth condition detection devices.

5. The power tool of claim 1, wherein the operation control device is configured to exhibit a plurality of control patterns with respect to the RPM of the drive motor and the transmission gear ratio of the continuously variable transmission, the operation control device is configured to select one control pattern out of the plurality of control patterns based on the condition of the power tool detected by the condition detection device, and the operation control device is configured to control the RPM of the drive motor and the transmission gear ratio of the continuously variable transmission by the selected control pattern.

6. The power tool of claim 5, wherein the plurality of control patterns includes a control pattern in which an efficiency of the drive motor is optimized, and a control pattern in which the output of the drive motor is optimized.