HVAC Actuator Reset Mechanism With Eccentric Torsion Spring
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Solution Overview
Problem
Existing electric actuators for HVAC systems have complex reset mechanisms, such as flat spiral springs or capacitors, which require maintenance and are not simple or compact, posing challenges in stability and operational reliability.
Innovation Solution
A compact and simple reset mechanism using a torsion spring and eccentric mechanism, where the center of rotation of the eccentric mechanism deviates from the center of torsion of the torsion spring, compensating for the change in restoring torque with torsion angle, ensuring stable and smooth resetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat spiral spring reset mechanism is used, then the output restoring force is stable, but the structure becomes complex
Solution Approach 1:
The patent replaces the traditional flat spiral spring mechanical reset mechanism with an electric motor-driven system. The motor (21) directly drives the valve stem (12) through a transmission mechanism, eliminating the need for complex mechanical springs while maintaining reliable resetting function through electrical control.
Solution Approach 2:
The reset function is separated from the mechanical spring system and integrated into the electric motor control system. The motor's rotational motion is segmented and transmitted through gears (23, 24) and a rack (26) to achieve linear motion of the valve stem, providing stable restoring force through controlled mechanical stages.
2Reliability
If a capacitor reset mechanism is used, then resetting function is provided, but monitoring and maintenance are necessary
Solution Approach 1:
The electric motor-driven system provides self-service resetting capability. The motor automatically drives the valve stem back to the initial position when power is restored or reset signal is received, eliminating the need for manual monitoring and maintenance of energy storage capacitors while maintaining reliable resetting function.
3Device complexity
If the center of rotation of the eccentric mechanism coincides with the center of torsion of the torsion spring, then the structure is simple, but the restoring torque varies significantly with torsion angle
Solution Approach 1:
The patent introduces an eccentric mechanism where the center of rotation (O1) is deliberately offset from the center of torsion (O2) of the torsion spring (31). This asymmetric arrangement creates a variable torque arm length that compensates for the torsion spring's non-linear torque characteristics, providing more stable restoring torque throughout the rotation range while maintaining relatively simple structure.
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
The solution provides a stable restoring torque, allowing for a compact and easy-to-operate electric actuator that can smoothly reset the valve to its initial position, even in the absence of power, enhancing safety and reliability.
Implementation Method 1
a torsion spring (31), which is capable of outputting a restoring force as a function of a torsion angle when the motor (11) stops working
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
The present invention provides an actuator for a heating, ventilating and air conditioning system, which comprises: a motor (10); an actuation end (20) driven by the motor; and a reset mechanism (40). The reset mechanism (40) comprises: a torsion spring (42), which is capable of outputting a restoring force as a function of a torsion angle when the motor stops working; and an eccentric mechanism (44) which is driven to rotate by the restoring force of the torsion spring and outputs a restoring torque, wherein a center of rotation of the eccentric mechanism is arranged to deviate from a center of torsion of the torsion spring.