Speed changing tool

Abstract

The invention discloses a speed changing tool, which comprises a shell, a motor, an output shaft, a gear transmission mechanism and a control system, wherein the motor is arranged in the shell and outputs rotating power; the gear transmission mechanism is arranged between the motor and the output shaft to transmit rotating output of the motor to the output shaft and comprises a gear train and a movable piece; the movable piece can move between a first position and a second position to output the rotating speed of the motor in different speed reducing ratios through the gear transmission mechanism; the gear train comprises at least one gear ring; the control system comprises a driving device matched with the movable piece; the driving device is used for cutting off current of the motor when the speed reducing ratios of the gear transmission mechanism are needed to be changed and driving the movable piece to be switched between the first position and the second position; the gear ring is connected to the shell in a rotatable mode through at least one energy storage unit, has a balance position and at least one energy storage position, and is limited to continuously rotate after rotating to the energy storage position; and the energy storage unit always applies force to the gear ring at the balance position.

Description

technical field [0001] The invention relates to a variable speed tool, in particular to a tool driven by a motor with a variable speed transmission mechanism that can output different rotational speeds, such as electric drills, screwdrivers and hammer drills. Background technique [0002] A variable speed tool, such as an electric drill, screwdriver and hammer drill, etc., has a variable speed transmission mechanism that can output different speeds to adapt to different load torques. The speed change transmission mechanism of the speed change tool usually includes a gear transmission mechanism connecting the motor and the output shaft and a control system. The control system changes the transmission ratio by changing the meshing relationship with the gear transmission mechanism, so that the output shaft outputs different speeds. In the prior art, such as the automatic transmission mechanism disclosed in U.S. Patent No. 6824491, its control system can automatically adjust the...

AI Technical Summary

Problems solved by technology

The above-mentioned automatic transmission mechanisms realize automatic gear shifting based on the change of the positional relationship between the mechanical structures corresponding to the change of the output torque. This mechanical transmission mechanism not only makes the internal mechanical structure of the gear transmission mechanism more complicated, but also due to the It is also rotating while moving axially, and the housing is relatively fixed, so when the speed change mechanism is shifting, the teeth of the rotating ring gear and the teeth of the anti-rotation device on the housing will collide with each other and it is difficult to meshing, so the purpose of automatic gear shifting and industrial implementation cannot be really realized

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