Trigger Switch Actuator Dynamics for Motor Speed Control
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Solution Overview
Problem
Existing speed change switches for motors face difficulties in fine adjustment of rotation speed due to the requirement for small displacement of the actuator to maximize rotation speed, and the need for large movement of the actuator to control motor speed proportionally to applied force, making precise control challenging.
Innovation Solution
A trigger switch with a pressure-sensitive sensor and a pressing member that applies force corresponding to the actuator's movement, using a conversion member to convert movement to force when the actuator's movement is small, and direct linkage for larger movements, along with a limitation mechanism to prevent excessive force, allowing for fine adjustment of motor speed with reduced actuator movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conversion of the amount of displacement of the actuator to pressing force is implemented, then the amount of movement of the actuator is reduced, but fine adjustment of motor speed becomes difficult
Solution Approach 1:
The pressing member is designed to dynamically switch between two operational modes: linked to the actuator for small movements to enable fine adjustment, and directly pressing the load sensor for large movements to maximize motor speed. This dynamic reconfiguration resolves the contradiction by adapting the system's mechanical configuration to the required control precision.
Solution Approach 2:
The pressing member acts as an intermediary between the actuator and the load sensor, providing two different transmission paths: one through the conversion member for precise control, and another direct path for full-range control. This intermediary mechanism allows the system to select the appropriate transmission mode based on the required adjustment precision.
2Measurement precision
If a small spring constant of the elastic body is used, then fine adjustment of motor speed is enabled, but large movement of the actuator is required to maximize motor rotation
Solution Approach 1:
The system dynamically switches between two mechanical configurations: when fine adjustment is needed, the pressing member links to the actuator through the conversion member; when maximum speed is required, the pressing member directly presses the load sensor, bypassing the conversion member. This eliminates the need for large actuator movements while maintaining fine adjustment capability.
Solution Approach 2:
The control range is segmented into two zones: a fine adjustment zone for low-speed control and a high-speed zone for maximum power output. The pressing member transitions between these zones by changing its linkage configuration, allowing the system to achieve both fine adjustment and rapid response without requiring large actuator travel.
3Device complexity
If direct transmission of pressing force to the load sensor is implemented, then motor speed control is simplified, but fine adjustment of motor speed becomes difficult
Solution Approach 1:
The pressing member dynamically adjusts its mechanical advantage by switching between two configurations: linked to the actuator for amplified fine control, and directly pressing the load sensor for direct force transmission. This dynamic adaptation maintains simple control while enabling fine adjustment when needed.
Solution Approach 2:
Different transmission characteristics are applied to different portions of the actuator's travel range: the conversion member provides high mechanical advantage for fine adjustment in the initial range, while direct transmission provides linear control for the remaining range. This local differentiation resolves the contradiction between simplicity and precision.
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
Facilitates fine adjustment of electric power and motor speed with reduced actuator movement, prevents unintentional pressing, and limits excessive force applied to the pressure-sensitive sensor, enhancing control precision and preventing overload.
Implementation Method 1
a compression spring intervening between the actuator and the pressing member
Implementation Method 2
a pressure sensitive sensor to detect applied pressing force
Data Source
Figure 1~3
Figure 4~6
Figure 7
AI summary
It is enabled to facilitate fine adjustment of power as well as reduction of the amount of movement required to maximize the power. An actuator 13 is moved by operation of a user. A pressure sensitive sensor 15 detects applied pressing force. A pressing member 14 presses the pressure sensitive sensor 15. When the amount of movement of the actuator 13 is smaller than a predetermined amount, the pressing member 14 presses the pressure sensitive sensor 15 to apply force corresponding to the amount of movement of the actuator 13. When the amount of movement of the actuator 13 is not smaller than the predetermined amount, the pressing member 14 presses the pressure sensitive sensor 15 to apply force corresponding to pressing force applied to the actuator 13 by the user.