Throttle Passage Insert Forming for Stable Refrigerant Flow
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Solution Overview
Problem
Conventional throttle passages in automotive air conditioners are costly and prone to generating foreign matter or damage due to press-fitting or screwing, leading to noise and pressure issues from refrigerant bubbles during varying heat exchange conditions.
Innovation Solution
A method of forming a throttle passage by machining a circular plate into a truncated conical shape and deforming it to fit within the refrigerant passage, using a malleable material like pure aluminum or stainless steel, to create a fixed engagement without press-fitting or screwing, thus reducing noise and pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a throttle passage member is formed by press-fitting or screwing into the refrigerant passage, then the throttle passage can be assembled, but the cost increases and foreign matter or damage may be generated
Solution Approach 1:
The throttle passage member is integrated directly into the refrigerant passage structure through deformation engagement, eliminating the need for separate assembly operations like press-fitting or screwing. The member is formed to have an outer periphery that engages with the inner wall of the refrigerant passage, merging the throttle function with the passage structure itself.
Solution Approach 2:
The throttle passage member is deformed from its initial shape to a engaged shape where the outer periphery is expanded to fit tightly against the inner wall of the refrigerant passage. This parameter change in shape and dimension enables secure fixation without requiring additional fastening operations.
2Reliability
If conventional press-fitting or screwing methods are used to form the throttle passage, then the throttle passage member can be fixed, but foreign matter is generated from sliding surfaces causing noise and pressure issues
Solution Approach 1:
The harmful sliding contact between the throttle passage member and the refrigerant passage wall is eliminated by using a deformation engagement method. The member is deformed to expand its outer periphery and engage with the inner wall without sliding, thereby extracting the source of foreign matter generation and noise.
Solution Approach 2:
The potential harm of contact between the throttle passage member and the refrigerant passage is converted into a beneficial interference fit. The deformation process creates a tight engagement that secures the member in place while preventing harmful sliding contact and foreign matter generation.
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 method allows for cost-effective and noise-reduced formation of throttle passages that prevent refrigerant bubbles from forming, maintaining stable refrigerant flow and reducing the likelihood of liquid refrigerant blocking passages, thereby minimizing noise and pressure changes.
Implementation Method 1
squashing the throttle passage member from an expanded side of the refrigerant passage while pressing the throttle passage member against the step portion, to deform the throttle passage member such that the outer periphery of the throttle passage member is widened
Data Source
AI summary
A throttle passage is formed by providing a step portion by expanding an open end side of a refrigerant passage of the refrigeration cycle, placing a throttle passage member on the step portion, and squashing the throttle passage member using a columnar squashing jig to widen a rim of the outer periphery, thereby causing the throttle passage member to be fixedly engaged to an inner wall of the refrigerant passage. The throttle passage member has a simple shape formed only by machining a circular plate having a hole formed in a center thereof into a truncated conical shape, and therefore can be made at low cost. Throttle passage member is only squashed to be fixedly engaged in the refrigerant passage, and therefore can be easily formed.