Vehicle Damper Mechanism Cam Groove End Shape for Initialization Stability
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Solution Overview
Problem
The existing damper opening/closing mechanism in vehicle air-conditioning devices experiences unstable initialization due to the damper lever rotating in the direction of opening, leading to an unstable closed state, especially when the direction of the damper lever applies torque in the opening direction during reference positioning by a stepping motor.
Innovation Solution
The mechanism incorporates a cam groove with a unique end portion shape that includes a curved surface or flat surface connecting points A and B, ensuring the pin is securely housed without clearance, preventing rotation in the opening direction and maintaining the damper in a closed state during initialization, regardless of the damper lever's direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cam groove has a groove width with clearance for the pin and an arc-shaped end portion, then the pin can be slidably fitted in the cam groove, but the damper lever rotates in the opening direction during initialization, causing unstable initialization
Solution Approach 1:
The invention applies local quality by making the end portion of the cam groove have a different shape (flat or curved surface) compared to the main groove body. This localized shape change at the end portion prevents the pin from rotating in the opening direction during initialization, while maintaining the slidable fitting function in the main groove body.
Solution Approach 2:
The invention applies preliminary action by pre-configuring the end portion of the cam groove with a flat or curved surface that prevents opening-direction rotation before initialization occurs. This preliminary structural design ensures that when the pin reaches the end portion during initialization, it cannot rotate in the opening direction, thus preventing unstable initialization.
2Speed
If the pin is fitted in the cam groove with clearance, then the damper lever can rotate smoothly, but torque in the opening direction causes the pin to return along the arc surface by clearance, opening the damper
Solution Approach 1:
The invention makes the end portion of the cam groove have a different shape (flat or curved surface) compared to the main groove body. This localized shape change prevents the pin from rotating in the opening direction when torque is applied, while maintaining smooth rotation capability in the main groove body through the clearance design.
3Measurement precision
If the cam groove end portion has an arc shape with radius of 1/2 groove width, then the pin can contact the end surface, but the pin returns along the arc surface by clearance, leading to unstable initialization
Solution Approach 1:
The invention changes the shape of the end portion of the cam groove from an arc shape to a flat or curved surface. This localized shape modification ensures that when the pin contacts the end portion, it cannot rotate in the opening direction, thus preventing the return along the arc surface and ensuring stable initialization while maintaining reference positioning accuracy.
Data Source
AI summary
Provided is a damper opening/closing mechanism of a vehicle air-conditioning device, the damper opening/closing mechanism being configured such that a pin (28) of a damper lever (26) is fitted in a cam groove (24) of a link plate (22) rotatably driven by a stepping motor and that a damper (19) is opened/closed through the damper lever (26) rotated by rotation of the link plate (22). One end portion of the cam groove (24) for reference positioning of the stepping motor is in such a shape that a connection surface (32) not contacting an outer peripheral surface of the pin (28) connects between the point of contact of the outer periphery of the pin (28) with one end surface of the cam groove (24) and the point with a side wall surface (24A) of the cam groove (24) when the damper (19) is in a closed state.