Pressure-Sensing Electric Tool Structure for Reliable Speed Control
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Solution Overview
Problem
The existing electric tools with piezoelectric elements in the output shaft suffer from reliability degradation due to the rotation of these elements, which affects the precision and longevity of speed control.
Innovation Solution
An electric tool design featuring a pressure-sensitive sensor supported by a separate structure, allowing the output shaft to rotate independently of the sensor, thus preventing damage and enhancing reliability in rotation control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the piezoelectric element is disposed in the output shaft to enable speed control, then the rotational speed can be controlled, but the piezoelectric element may be damaged by rotation which degrades reliability
Solution Approach 1:
The device is divided into two independent rotating systems: the output shaft that rotates with the motor, and the sensor support that remains stationary. The pressure-sensitive sensor is placed in the stationary sensor support rather than in the rotating output shaft, separating the sensing function from the rotating drive mechanism. This segmentation prevents the sensor from being damaged by rotation while maintaining speed control capability through pressing force detection.
Solution Approach 2:
A stationary sensor support acts as an intermediary structure that holds the pressure-sensitive sensor. This intermediary component transmits the pressing force from the bit to the sensor without subjecting the sensor itself to rotational motion. The sensor support mediates between the rotating output shaft and the stationary sensor, enabling reliable force detection while protecting the sensor from rotational damage.
2Device complexity
If the pressure-sensitive sensor rotates with the output shaft, then the structure can be simplified, but the sensor may be damaged which affects measurement precision
Solution Approach 1:
The device is divided into two independent rotating systems: the output shaft that rotates with the motor, and the sensor support that remains stationary. The pressure-sensitive sensor is placed in the stationary sensor support rather than in the rotating output shaft, separating the sensing function from the rotating drive mechanism. This segmentation prevents the sensor from being damaged by rotation while maintaining speed control capability through pressing force detection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration ensures that the pressure-sensitive sensor is not damaged by rotation, maintaining the reliability and precision of speed control, and preventing degradation in rotation control reliability.
Implementation Method 1
a piezoelectric element disposed at a back of a bit attachment hole... A rear end of a bit fit into the bit attachment hole is pressed against a front surface of the piezoelectric element. As a result, the resistance value of the piezoelectric element changes.
Data Source
AI summary
An electric tool includes a pressure-sensitive sensor, a support, an output shaft, and a controller. The pressure-sensitive sensor is configured to sense pressing force which is externally provided. The support supports the pressure-sensitive sensor. The output shaft is configured to hold a tip tool and be rotated relative to the support by motive power provided from an electric motor with the output shaft holding the tip tool. The controller is configured to control rotation of the output shaft in accordance with an output according to the pressing force, the output being output from the pressure-sensitive sensor.