Geared Machine Bearing with Segmented Groove for Speed Adaptation
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Solution Overview
Problem
Existing gear machines are designed for specific gear speeds and deviate from optimal performance when operated at different speeds, leading to excessive wear on bearing journals and bearing bores, reducing their service life.
Innovation Solution
A groove is designed to run continuously around the bearing journal with a recess on one side connected to a closed supply channel for discharging pressure fluid, allowing the groove to be essentially pressureless, and the pressure fluid flows back into the bearing gap in a low-pressure zone, creating a hydrodynamic lubricating film that separates the bearing journal from the bore at both high and low speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gear machine is designed for a specific gear speed with a conventional bearing setup, then it operates efficiently at that design speed, but excessive wear occurs on the bearing journals or bearing bore when the speed deviates from the design speed
Solution Approach 1:
The bearing bore is segmented into multiple zones along the direction of rotation, with different zones serving different functions: some zones provide hydrodynamic lubrication for high-speed operation, while others provide hydrostatic lubrication for low-speed operation. This segmentation allows the bearing to adapt to different speed conditions without excessive wear.
Solution Approach 2:
The bearing system dynamically transitions between hydrodynamic and hydrostatic lubrication modes depending on the operating speed. At high speeds, the continuous groove enables hydrodynamic lubrication where pressure fluid is generated by relative motion. At low speeds, the recesses enable hydrostatic lubrication where pressurized fluid is supplied through feed channels to maintain the lubricating film.
2Speed
If a continuous groove is provided in the bearing bore without recesses, then the bearing can operate at high speeds with hydrodynamic lubrication, but the lubricating film collapses at low speeds causing excessive wear
Solution Approach 1:
The continuous groove is segmented by introducing recesses that are connected to feed channels. These recesses create discrete zones that can be independently pressurized through the feed channels, enabling hydrostatic lubrication at low speeds while maintaining the continuous groove structure for hydrodynamic lubrication at high speeds.
3Reliability
If pressurized fluid is supplied continuously to the entire bearing bore, then lubrication is maintained at all speeds, but the pressure fluid disturbs the formation of the hydrodynamic lubricating film at high speeds
Solution Approach 1:
Pressurized fluid supply is localized to specific recesses rather than being distributed continuously throughout the bearing bore. The feed channels supply pressurized fluid only to the recesses that are not currently engaged in hydrodynamic lubrication, allowing the continuous groove to maintain hydrodynamic lubrication at high speeds while providing hydrostatic support where needed.
4Reliability
If the groove is connected to pressurized fluid supply, then lubrication is maintained at low speeds, but the pressure fluid cannot be discharged effectively causing excessive pressure in the groove
Solution Approach 1:
The excess pressure fluid is extracted from the groove and redirected back into the bearing gap through the recesses. The recesses serve dual functions: they supply pressurized fluid to maintain the lubricating film at low speeds, and they drain excess pressure fluid from the groove to prevent pressure buildup that would disturb hydrodynamic film formation at high speeds.
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 prevents excessive wear by maintaining a lubricating film at varying gear speeds, ensuring the gear machine's longevity and operational efficiency across different speed ranges.
Implementation Method 1
a hydrodynamic lubricating film forms between the bearing journal and the bearing bore, which completely separates the bearing journal from the bearing bore
Implementation Method 2
the pressure fluid, which flows out of the bearing gap between the bearing journal and the bearing bore into the groove, is discharged from the groove essentially without pressure. This is preferably done in that the pressure fluid flows out of the groove back into the bearing gap, specifically into a zone in which there is a low pressure
Implementation Method 3
In the second region, in which the first recess is arranged, pressurized fluid under pressure is introduced into the bearing gap via the feed channel and the first recess. This means that a lubricating film can form even at a very low speed of the gearwheels
Data Source
Figure 1
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Figure 4~5
AI summary
The machine (10) has two gear wheels (11) externally engaged with one another and surrounded by a housing (30). The gear wheels comprise a bearing pivot (13), which is rotatably accommodated in an assigned bearing bore (51) of the housing with respect to a rotational axis (14). The bore or pivot is provided with a groove, which is covered by a counterpart, the pivot or bore. The groove is endlessly rotatingly formed around the pivot. A recess i.e. oblong hole, is formed in the bore beside the groove and connected with a closed feed channel for supplying pressure fluid i.e. hydraulic oil.