Reciprocating Compressor Bearing with Recessed Clearance Zones
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Solution Overview
Problem
Reciprocating compressors experience increased friction losses due to the longer journal portion, which affects efficiency, especially under varying load conditions, as it supports large loads effectively but increases friction when loads are small.
Innovation Solution
The compressor design includes a shaft with a first and second journal portion, where the first journal portion is closer to the connecting rod and the second farther away, with corresponding recessed portions in the bearing to increase clearance and reduce friction, specifically forming a larger bearing clearance in ranges where the bearing makes a small contribution to support the shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the journal portion is made longer to support large loads, then the load-bearing capacity is improved, but the friction losses increase
Solution Approach 1:
The bearing is designed with non-uniform clearance distribution, creating different clearance characteristics in different circumferential regions. The first recessed portion creates a localized region with larger clearance where the bearing makes small contribution to support, while other regions maintain smaller clearance for better load support. This local differentiation allows the bearing to optimize both load-bearing capacity and friction losses in different zones.
2Reliability
If the journal portion is made longer to support large loads, then the reliability is improved, but the energy efficiency deteriorates
Solution Approach 1:
The bearing clearance is locally modified by adding the first recessed portion, which creates a larger clearance region in areas where the bearing contributes minimally to shaft support. This local modification reduces friction and improves energy efficiency without compromising the overall reliability of shaft support, as the critical load-bearing regions maintain appropriate clearance characteristics.
3Loss of energy
If the bearing clearance is increased to reduce friction losses, then the energy efficiency is improved, but the load-bearing capacity may be impaired
Solution Approach 1:
Instead of uniformly increasing bearing clearance, the invention applies localized clearance increase only in the first recessed portion where the bearing makes small contribution to support. This selective approach reduces friction losses in non-critical regions while maintaining smaller clearance in load-critical regions, thereby improving energy efficiency without significantly compromising load-bearing capacity.
Solution Approach 2:
The bearing clearance is segmented into different regions with different characteristics: the first recessed portion has larger clearance for reduced friction, while other regions maintain smaller clearance for better load support. This segmentation allows simultaneous optimization of both friction losses and load-bearing capacity in different zones of the bearing.
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
This design reduces friction losses without impairing the bearing's ability to support the shaft, thereby enhancing the compressor's efficiency by optimizing the bearing clearance and supporting forces.
Implementation Method 1
the bearing has a first sliding portion for supporting the first journal portion and a second sliding portion for supporting the second journal portion
Data Source
AI summary
Provided is a reciprocating compressor having a structure in which friction losses between a shaft and a bearing can be reduced without impairing the ability of the bearing to support the shaft. A reciprocating compressor (100) includes a cylinder (5), a piston (4), a connecting rod (6), a shaft (1), and a bearing (2). The shaft (1) has a journal portion (28) as a portion covered by the bearing (2). The journal portion (28) has a first journal portion (7) located closer to the connecting rod (6) with respect to a midpoint M of the journal portion (28) in a direction parallel to a rotational axis and a second journal portion (8) located farther from the connecting rod (6) with respect to the midpoint M. The bearing (2) has a first sliding portion (10) for supporting the first journal portion (7) and a second sliding portion (11) for supporting the second journal portion (8). The first sliding portion (10) has a first recessed portion (29) in at least one range selected from a range of 0° to 180° and a range of 270° to 360° in a rotational direction of the shaft (1) from a reference position.