Piston Limiting Structure Prevents Auto-Rotation Without Clearance Volume
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Solution Overview
Problem
Circular pistons in rotary cylinder piston compressors tend to auto-rotate, causing interference and collision with the cylinder, and existing limiting structures introduce clearance volumes or require complex machining, affecting assembly and performance.
Innovation Solution
A piston limiting structure featuring a circular piston hole and a limiting member that abuts against a non-penetrating limiting surface on the piston to prevent auto-rotation without introducing clearance volume, using a cylindrical limiting pin for easy machining and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circular piston with a pin limiting structure is used, then piston auto-rotation is prevented, but a through avoidance groove is required in the piston hole which introduces clearance volume and affects air suction-exhaust process
Solution Approach 1:
The invention extracts the harmful through avoidance groove from the piston hole structure and replaces it with a limiting member arranged in a limiting hole that penetrates the cylinder wall. This removes the source of clearance volume while maintaining the piston limiting function through a separate limiting mechanism.
Solution Approach 2:
The invention introduces a limiting member as an intermediary element that mediates between the piston and the cylinder. This limiting member, arranged in a limiting hole, provides the necessary constraint against piston auto-rotation without requiring modifications to the piston hole that would create clearance volume.
2Reliability
If a non-circular piston is used to prevent auto-rotation, then piston rotation is limited, but machining complexity increases and assembly accuracy becomes difficult to guarantee
Solution Approach 1:
The invention segments the piston limiting function from the piston and cylinder main structures. Instead of making the piston or cylinder non-circular, a separate limiting member is used to provide the limiting function, keeping the main components simple and easy to manufacture.
Solution Approach 2:
The limiting member serves as an intermediary that provides the rotation limiting function without requiring complex machining of the piston or cylinder. This allows both the piston and cylinder to maintain simple circular cross-sections for easy manufacturing while still achieving the desired limiting effect.
3Reliability
If a through avoidance groove is used in the piston hole, then piston limiting is achieved, but the groove location affects sealing requirements and increases machining difficulty
Solution Approach 1:
The invention removes the avoidance groove from the piston hole structure and extracts the limiting function to a separate limiting member arranged in a limiting hole. This eliminates the need for complex sealing arrangements around a groove in the piston hole.
Solution Approach 2:
Instead of modifying the piston hole with an avoidance groove, the invention creates a separate limiting hole structure that copies the limiting function. This separate structure simplifies the piston hole and reduces sealing complexity by avoiding the need to maintain seals around a groove.
Data Source
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Figure 3~4A
AI summary
Some embodiments of a disclosure provide a piston limiting structure, a compressor, and a heat exchange apparatus. The piston limiting structure includes: a cylinder (1), having a piston hole (11) perpendicular to an axial direction of the cylinder (1) and penetrating the cylinder (1), wherein a projection of the piston hole (11) in a penetrating direction is circular; a piston (2), disposed in the piston hole (11) in a form-fit manner and slid in the piston hole (11) in a reciprocating manner, wherein a side wall of the piston (2) is provided with a limiting surface (21), and the limiting surface (21) does not penetrate two ends of the side wall of the piston (2) along an axial length of the piston (2); and a limiting member (3), wherein the cylinder (1) is provided with a limiting hole (13) penetrating from an outer wall of the cylinder (1) to the piston hole (11), the limiting member (3) is mounted in the limiting hole (13) in the form-fit manner, and the limiting member (3) abuts against the limiting surface (21) to limit a rotation of the piston (2) around an axis of the piston itself. The piston limiting structure does not introduce a clearance volume, and has a better limiting effect on the piston (2).