Flow Channel Switching Valve Angle Shaft for Precise Positioning
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Solution Overview
Problem
Conventional flow channel switching valves face precision issues due to errors in rotation angle detection caused by tolerances in the valve member, valve stem, and rotation angle sensor, leading to inaccuracies in the rotational position of the valve member.
Innovation Solution
A flow channel switching valve design incorporating a rotation angle output shaft with small, medium, and large-diameter portions, supported rotatably in an attachment hole with a press-fit configuration, which allows for precise positioning and fixation, reducing detection errors and ensuring accurate rotational positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotation angle sensor is combined with the valve stem to detect rotational position, then the rotational position can be detected, but detection precision deteriorates due to error accumulation from tolerances in the valve member, valve stem, and sensor
Solution Approach 1:
The patent introduces a rotation angle output shaft as an intermediary component between the valve stem and the rotation angle sensor. This shaft is press-fitted into the valve stem and rotates together with it, serving as a dedicated interface for angle detection. By separating the detection function from the valve stem structure, the intermediary shaft reduces error transmission and improves detection precision while maintaining reliability.
2Manufacturing precision
If conventional press-fitting is used to attach the rotation angle sensor, then assembly is simple, but positioning precision deteriorates due to tolerance accumulation
Solution Approach 1:
The patent segments the attachment structure into multiple functional portions: a small-diameter portion for press-fitting into the valve stem, a medium-diameter portion for forming a press-fit portion, and a large-diameter portion for support. This segmentation allows each portion to serve a specific function (secure attachment, precise positioning, structural support) while maintaining overall assembly simplicity through integrated design.
3Strength
If the rotation angle output shaft is directly press-fitted into the valve stem, then fixation is secure, but positioning accuracy deteriorates due to inclined press-fitting
Solution Approach 1:
The patent applies local quality by providing different diameter portions at different locations of the rotation angle output shaft. The small-diameter portion enables press-fitting for secure fixation, while the large-diameter portion provides support to prevent inclined press-fitting. Each local portion has optimized dimensions to fulfill its specific function, achieving both strong fixation and high positioning accuracy.
Data Source
AI summary
A flow channel switching valve includes a valve stem that is attached to a ball valve member. The flow channel switching valve includes a potentiometer shaft that is press-fitted into an attachment hole provided in an end surface of the valve stem, and a potentiometer that detects a rotation angle of the potentiometer shaft around an axis. The potentiometer shaft has a small-diameter portion, a medium-diameter portion, and a large-diameter portion that are sequentially connected in a direction of the axis, and is supported rotatably around the axis in the attachment hole in an inserted state before being press-fitted into the attachment hole. The large-diameter portion is press-fitted into an upper end portion of the attachment hole.