Hydraulic Machine Support Bearings for Parasitic Load Separation
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Solution Overview
Problem
Hydraulic machines face issues with parasitic forces generated by pistons and distributors, which disrupt engine bearings, leading to bending, jamming, and reduced rotational efficiency, necessitating either increased mass or reduced performance to compensate for these forces.
Innovation Solution
The addition of a third guide bearing that absorbs parasitic forces, allowing the first and second bearings to remain dedicated to transmission efforts without interference, thereby reinforcing robustness and enabling reduced size without performance loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two bearings are used to guide shaft rotation, then the structure is simple, but parasitic forces from pistons and distributors disrupt the bearings, causing bending, jamming, and reduced rotational efficiency
Solution Approach 1:
The patent divides the bearing support function into three separate bearings: two bearings (26, 28) dedicated to supporting radial and axial loads from the shaft rotation, and a third bearing (37) specifically dedicated to absorbing parasitic forces from the pistons and distributor. This segmentation isolates the harmful parasitic forces from the main load-bearing bearings, preventing them from causing bending, jamming, or reduced rotational efficiency.
2Strength
If bearing size is increased to withstand parasitic forces, then bearing robustness improves, but machine size increases
Solution Approach 1:
By segmenting the bearing functions, each bearing can be optimized for its specific purpose. The two main bearings (26, 28) can be sized appropriately for shaft support without needing to be oversized to handle parasitic forces, while the third bearing (37) is specifically designed to absorb parasitic forces. This results in more compact overall machine size compared to using fewer, larger bearings.
Solution Approach 2:
The third bearing (37) acts as an intermediary element that specifically absorbs parasitic forces from the pistons and distributor before they can affect the main shaft support bearings. This intermediary bearing protects the primary bearings from harmful forces without requiring them to be oversized.
3Stability of the object's composition
If preload on bearings is increased to compensate for parasitic axial forces, then bearing stability improves, but rotational efficiency decreases due to binding
Solution Approach 1:
The third bearing (37) serves as a dedicated intermediary that absorbs parasitic axial forces from the pistons and distributor. By providing this specialized force absorption path, the patent eliminates the need to increase preload on the main bearings (26, 28) to compensate for these forces. The main bearings can operate with optimal preload settings, maintaining high rotational efficiency without energy loss from binding, while still achieving the required stability through the combined support of all three bearings.
Data Source
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AI summary
The rotating hydraulic machine (102) comprises: - a housing (10), - a shaft (20) movably mounted relative to the housing about an axis, - an apron (24) rigidly connected to the shaft and extending around at least a portion of the housing, - a cam (12) rigidly connected to either the housing or the shaft, - a cylinder block (42) rotationally connected to the other of either the housing or the shaft, the cylinder block comprising pistons capable of engaging with the cam to produce a relative rotation between the shaft and the housing, - first and second guide bearings (28) each bearing directly on the housing and the apron, and - at least a third guide bearing (37) bearing directly on the housing and the cylinder block.