Valve Actuator Cam Mechanism to Prevent Over-Torque Damage

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Solution Overview

Problem

Existing valve actuators for air conditioners face issues with sensor instability in harsh environments and require separate PCBs for motor stop signals, leading to potential damage from over-torque and inaccurate RPM control.

Innovation Solution

A valve actuator design that utilizes a mechanical cam and groove mechanism for power transmission, eliminating the need for electronic sensors and separate PCBs, and includes a selective power transmission unit to prevent over-torque damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electronic sensors and PCBs are used for motor control, then valve actuation control is achieved, but sensor instability occurs in harsh environments

Engineering Contradiction:
Improvesensor stabilityVSAvoidelectronic component complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces electronic sensors and PCB-based motor control with a purely mechanical control system. A cam mechanism with a groove structure mechanically detects the rotation angle of the output gear and automatically interrupts power transmission at the predetermined 90-degree position, eliminating electronic components entirely and ensuring stable operation in harsh environments.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The mechanical cam mechanism performs multiple functions automatically: it detects the rotation angle, determines when the valve reaches the predetermined position, and interrupts power transmission without requiring external electronic control systems. The system serves itself through the mechanical interaction between the cam groove and the output gear.

Inventive Principle:
Principle #25Self-service

2Strength

If continuous power transmission is provided to the motor, then valve actuation is maintained, but over-torque damage occurs to gears and motor

Engineering Contradiction:
Improveprotection against over-torque damageVSAvoidcontinuous operation capability
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The cam mechanism is designed with a groove structure that proactively prevents over-torque damage by mechanically interrupting power transmission when the output gear reaches the predetermined rotation angle. This preliminary protective action stops the motor before excessive torque can damage the gears or motor, while still achieving complete valve actuation.

Inventive Principle:
Principle #9Preliminary anti-action

3Measurement precision

If electronic limit switches and PCBs are used for motor stop control, then valve position control is achieved, but additional components and cost are required

Engineering Contradiction:
Improvevalve position control accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes electronic control components (limit switches, PCBs, sensors) from the system, retaining only the essential mechanical elements needed for position control. The cam groove structure alone performs the function of detecting valve position and controlling motor stop, simplifying the overall system while maintaining precise control.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enhances durability and driving stability by preventing gear and motor damage, while ensuring accurate control of the valve without electronic sensor instability and reducing material costs.

Implementation Method 1

a cam portion provided in at least one of the output gear and the valve output shaft

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP4137728B1Valve actuator
Publication Date: 2025.09.03 LG ELECTRONICS INC
  • EP4137728B1 patent drawingFigure 1
  • EP4137728B1 patent drawingFigure 2
  • EP4137728B1 patent drawingFigure 3

AI summary

Disclosed is a valve actuator, and a valve actuator according to an exemplary embodiment of the present disclosure includes: a motor; a gear assembly including an input gear rotated by driving force of the motor, an output gear receiving rotational force of the input gear, and at least one power transmission gear transmitting the rotational force of the input gear to the output gear; a valve output shaft actuated to close a path of a valve; and a selective power transmission unit selectively transmitting the rotational force of the output gear to the valve output shaft, and the selective power transmission unit includes a cam portion provided in at least one of the output gear and the valve output shaft. Accordingly, after the valve is actuated to close the path, the driving force of the motor is not transmitted to the valve output shaft.