Motor-Operated Valve Spring Layout for Backlash-Free Flow Control
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Solution Overview
Problem
Conventional motor-operated valves experience hysteresis issues due to backlash in the feed screw mechanism, leading to inconsistencies in flow rate control, and existing solutions like bellows are expensive and complicated to manufacture.
Innovation Solution
A motor-operated valve design with a coil spring arranged within the valve chamber to absorb backlash, allowing for precise control and reducing the vertical dimension, eliminating the need for expensive bellows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bellows are used to prevent coolant leakage and absorb backlash, then sealing performance is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the sealing function from the bellows component and implements it separately through a seal ring (O-ring) that prevents coolant leakage between the valve shaft and valve chamber wall. This separates the sealing function from the backlash absorption function, allowing each to be optimized independently and reducing overall device complexity.
Solution Approach 2:
The patent replaces expensive bellows with a simple, inexpensive seal ring (O-ring) that provides adequate sealing performance. The seal ring is a standard, readily available component that is much cheaper than custom-manufactured bellows, thereby reducing manufacturing cost while maintaining reliability.
2Manufacturing precision
If bellows are used to absorb backlash, then hysteresis is reduced, but manufacturing cost increases
Solution Approach 1:
The patent introduces a spring as an intermediary component between the valve shaft and the seal ring. This spring absorbs the backlash in the feed screw mechanism by providing elastic compression, thereby eliminating hysteresis and improving flow rate control precision without requiring expensive bellows.
Solution Approach 2:
The patent replaces expensive bellows with a simple, inexpensive spring that provides equivalent backlash absorption functionality. The spring is a standard mechanical component that is much easier and cheaper to manufacture, thereby reducing manufacturing cost while maintaining manufacturing precision.
3Manufacturing precision
If spring is arranged above the valve chamber to absorb backlash, then hysteresis is reduced, but vertical dimension increases
Solution Approach 1:
The patent nests the spring within the valve chamber space, positioning it between the valve shaft and the seal ring. This nested arrangement allows the spring to absorb backlash and reduce hysteresis without increasing the vertical dimension of the overall valve assembly, as it utilizes existing internal space rather than adding external height.
Solution Approach 2:
The patent repositions the backlash-absorbing spring from a vertical arrangement (above the valve chamber) to a horizontal arrangement (within the valve chamber, radially outward from the valve shaft). This dimensional change allows the spring to perform its function while minimizing impact on the vertical dimension of the valve.
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 effectively prevents hysteresis and allows for precise flow rate control while minimizing manufacturing costs and vertical dimensions, enhancing the operational efficiency and cost-effectiveness of the valve.
Implementation Method 1
a coil spring arranged in the valve chamber and acting on the valve shaft in the valve opening direction
Implementation Method 2
The valve shaft 124 is always urged downward by a compression coil spring 134 contracted in the valve shaft holder 132
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A motor-operated valve includes a driving unit including a rotor (8) and a stator (2), a feed screw mechanism (1c), and a valve main body unit (10). In order to remove backlash intrinsic in the feed screw mechanism (1c), a coil spring (70) that urges a valve body in a direction away from a valve seat (62) is arranged in a valve chamber. A spring bearing (73) that forms a housing, in which the coil spring is housed, in the valve chamber (12) is provided. Therefore, the large valve chamber is secured in the valve main body unit and passing sound is reduced when a fluid passes the motor-operated valve. Contact surfaces of the valve body and the coil spring can be aligning curved surfaces that absorb a bend of the coil spring.