Valve Drive Gear Switching to Prevent Step-Out and Noise
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Solution Overview
Problem
Conventional refrigerant valve devices experience noise and vibration due to step-out occurrences during reverse rotation, caused by the arm unit and abutted unit colliding, which restricts the pinion's rotation and results in excessive rotation to determine the origin position.
Innovation Solution
A valve drive device with a power transmission switching unit that allows switching between power transmission and non-transmission states, featuring a drive gear and driven gear with meshing and non-meshing units, and a rotation restriction unit to prevent collision and maintain power disconnection during reverse rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the motor is rotated in the reverse rotation direction to adjust the supply amount of the refrigerant, then the valve element can be positioned, but the arm unit of the output gear abuts on the abutted unit of the pinion, restricting the pinion's rotation and causing step-out and collision noise
Solution Approach 1:
The gear mechanism is segmented into meshing units and non-meshing units. The non-meshing unit provides a gap that prevents collision between the arm unit and abutted unit during reverse rotation, while the meshing unit enables power transmission during forward rotation.
Solution Approach 2:
The non-meshing unit acts as an intermediary that allows the pinion to rotate freely without engaging the driven gear, preventing direct collision between the arm unit and abutted unit while still enabling motor rotation for positioning.
2Measurement precision
If the pinion rotates excessively to position the origin after the arm unit and abutted unit abut against each other, then the origin position can be determined, but vibration and noise are generated between the arm unit and abutted unit
Solution Approach 1:
The gear is divided into meshing and non-meshing units, allowing the pinion to rotate through the non-meshing unit without engaging the driven gear, thus determining origin position without generating vibration or noise from gear collision.
Solution Approach 2:
The non-meshing unit is positioned to engage before the arm unit and abutted unit collide, allowing the pinion to complete its rotation to the origin position in advance, before any collision can occur.
3Reliability
If the meshing state between the drive gear and driven gear is maintained during reverse rotation, then power transmission is continuous, but the motor experiences step-out and collision noise occurs
Solution Approach 1:
The gear system dynamically switches between meshing and non-meshing states based on rotation direction. During reverse rotation, the non-meshing unit disengages to prevent step-out and collision, while during forward rotation, the meshing unit engages for reliable power transmission.
Solution Approach 2:
The gear mechanism periodically engages and disengages based on rotation direction and position, with the non-meshing unit providing periodic disengagement during reverse rotation to prevent harmful effects, while maintaining periodic engagement during forward rotation for reliable operation.
Data Source
AI summary
There is provided a valve drive device including: a base including a fluid inlet, a fluid outlet, and a valve seat surface, at least one of the fluid inlet and the fluid outlet being opened at the valve seat surface; a cover configured to define a valve chamber; a valve element configured to open and close any one of the fluid inlet and the fluid outlet in the valve chamber; and a valve element driver configured to drive and rotate the valve element. The valve element driver includes: a motor; a drive gear configured to rotate together with a rotor of the motor; a driven gear configured to rotate, in a state of meshing with the drive gear, the valve element by rotation of the drive gear; and a power transmission switching unit.