Single-Piece Crosshead for Reciprocating Compressor
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Solution Overview
Problem
Large reciprocating compressors experience excessive wear and friction due to transverse forces transmitted from the connecting rod to the piston, leading to failure in critical areas like the flange of the crosshead.
Innovation Solution
A single-piece crosshead design with a main body that decouples transverse movement of the crankpin from axial piston movement, using sliding shoes and a simplified structure to absorb sideways forces and reduce stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a multi-component crosshead design with flange and bolting holes is used, then the crosshead can be assembled with standard components, but critical stresses build up in the flange area leading to failure
Solution Approach 1:
The patent merges the flange, bolting holes, and main body into a single integrated crosshead component. This eliminates the separate flange that was prone to stress concentration and failure, while maintaining the necessary bolting functionality for assembly. The integration redistributes stresses throughout the entire crosshead structure rather than concentrating them in a localized flange area.
2Reliability
If a single-piece main body design is used, then stress concentrations are reduced and durability enhanced, but component complexity increases
Solution Approach 1:
While the main body is a single piece, the patent segments the functional areas into distinct zones: the main body for structural integrity, sliding shoes for force absorption, and bolting areas for assembly. This functional segmentation within a monolithic structure allows complex stress distribution requirements to be met while maintaining manufacturing feasibility through specialized casting or forging processes.
3Object-affected harmful factors
If sliding shoes are used to absorb sideways forces, then transverse forces are reduced protecting the piston, but the crosshead structure becomes more complex
Solution Approach 1:
The sliding shoes act as intermediary elements between the crosshead and the cylinder wall. They absorb and redirect transverse forces generated by the connecting rod, preventing these forces from being transmitted to the piston. The shoes convert harmful lateral forces into beneficial sliding contact forces, protecting the piston while adding minimal structural complexity.
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 single-piece crosshead design reduces component complexity, enhances durability by redistributing stress, and simplifies assembly, thereby minimizing wear and friction, and preventing flange failure.
Implementation Method 1
The sliding shoes themselves absorb the above mentioned sideway forces, allowing the crosshead to maintain the alignment with respect to the longitudinal axis of the piston
Data Source
AI summary
A crosshead for a piston rod is provided, which comprises a main body having a first and a second seat. The first seat is configured to hold a connecting rod, and the second seat is configured to hold a piston rod. The main body is made as a single piece.