Compressor Discharge Valve Anti-Shift Mechanism
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Solution Overview
Problem
In rotary compressors, the discharge valve can shift due to assembling backlash, leading to reduced compression efficiency and refrigerant reversal, especially in downsized or oval-shaped discharge holes, where the valve may not properly close the discharge hole.
Innovation Solution
The compressor design includes a recess with a fixation hole and an annular projection, where the discharge valve has a fixed portion with a protruding portion that contacts the recess wall when rotating, preventing shifting and ensuring proper closure of the annular projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the discharge valve is fixed using only a fixation hole and rivet, then the assembly is simple, but the discharge valve may rotate and shift due to assembling backlash
Solution Approach 1:
The protruding portion acts as an intermediary element between the discharge valve and the recess wall. It provides a contact surface that prevents rotation and shifting, while maintaining the simplicity of the rivet fixation method. This intermediary structure resolves the contradiction by adding a minimal geometric feature rather than a complete additional fixation mechanism.
Solution Approach 2:
The protruding portion is pre-formed on the discharge valve before assembly, creating a built-in anti-rotation feature. This preliminary action ensures that when the valve is installed, the positioning is already established, preventing assembling backlash from causing shifts. The feature is prepared in advance rather than requiring complex adjustment during assembly.
2Volume of moving object
If the recess length is shortened to downsize the compressor, then the compressor is more compact, but the discharge valve is more prone to rotation and shifting
Solution Approach 1:
Instead of increasing the overall recess length, the invention modifies the local geometry by adding the protruding portion at a specific location on the discharge valve. This localized feature provides the necessary anti-rotation capability without extending the recess length, thus maintaining the compact compressor size while improving reliability.
Solution Approach 2:
The solution moves from addressing the problem in the longitudinal dimension (recess length) to the radial dimension (protruding portion geometry). By creating a protrusion that contacts the recess wall, the invention solves the positioning problem in a different dimensional space, allowing short recess lengths while maintaining valve stability.
3Productivity
If the discharge hole has an oval shape to increase flow area, then the compression efficiency is improved, but the discharge valve is more likely to shift and fail to close properly
Solution Approach 1:
The oval-shaped discharge hole creates an asymmetric geometry that increases flow area but also makes the valve more prone to shifting. The protruding portion compensates for this asymmetry by providing a counterbalancing contact feature that ensures proper positioning. The asymmetric protrusion geometry matches the asymmetric valve hole shape, maintaining closure reliability despite the oval configuration.
Data Source
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AI summary
A discharge valve may be misaligned due to assembling backlash, and this may cause a head portion of the discharge valve to fail to properly close a discharge hole. When a discharge valve 31 rotates about a through hole 23b and a first straight portion 55 of a head portion 54 moves in a direction away from a drive shaft 12, a side surface 58a of a protruding portion 58 of a fixed portion 52 comes into contact with a side wall 24a of a recess 24, and thereby the rotation of the discharge valve 31 is restricted. Meanwhile, when the discharge valve 31 rotates about the through hole 23b and a second straight portion 56 of the head portion 54 moves in a direction toward the drive shaft 12, a side surface 58b of the protruding portion 58 of the fixed portion 52 comes into contact with a side wall 24c of the recess 24, and thereby the rotation of the discharge valve 31 is restricted.