Vehicle Gearbox Lubrication with Gravity Feed and Overflow Backup
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Solution Overview
Problem
Conventional gearbox lubrication methods, such as splash lubrication, reduce efficiency due to viscous friction and heating, and alternative systems relying on pumps can fail, leading to unreliability.
Innovation Solution
A gearbox design incorporating a reservoir with a lifting pump and overflow device ensures reliable lubrication by maintaining a minimum oil level, allowing gravity flow lubrication and preventing toothed wheel bubbling, with an optional heat exchanger to manage temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If splash lubrication is used, then the gears are constantly lubricated by oil, but the gearbox efficiency is reduced due to viscous friction and heating
Solution Approach 1:
The patent extracts the harmful effect of continuous oil immersion by introducing a controlled lubrication system with nozzles that deliver oil only to specific lubrication points on the gears, rather than having gears continuously bubble in oil. This reduces viscous friction while maintaining necessary lubrication.
Solution Approach 2:
The lubricating oil is pre-positioned in a reservoir above the gearbox casing, allowing gravity-fed delivery to nozzles that are positioned to target specific gear lubrication points before the gears complete their rotation, ensuring lubrication without continuous immersion.
2Loss of energy
If a pump is used to deliver oil from an elevated reservoir, then gravity flow lubrication can be achieved, but the system reliability decreases if the pump fails
Solution Approach 1:
The patent incorporates an overflow device that acts as a backup lubrication path. If the pump fails, oil automatically overflows from the reservoir through this device directly into the gearbox casing, ensuring continuous lubrication without requiring active pump control. This cushions against pump failure beforehand.
Solution Approach 2:
The overflow device serves as an intermediary backup system between the reservoir and the gearbox casing. It provides an alternative lubrication path that activates when the primary pump-driven system fails, ensuring lubrication reliability without compromising the efficiency benefits of the pump system during normal operation.
3Loss of energy
If the pump raises oil to maintain low oil level in casing, then gravity flow lubrication efficiency is improved, but the system complexity increases
Solution Approach 1:
The reservoir is positioned at an elevated location above the gearbox casing, utilizing gravity potential energy to feed oil to the nozzles. This eliminates the need for complex pressurization systems while maintaining controlled lubrication flow, reducing system complexity compared to alternative high-pressure lubrication systems.
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 design maintains gearbox efficiency and reliability by ensuring consistent lubrication, even if the pump fails, and prevents overheating through effective oil management and cooling.
Implementation Method 1
A lifting pump 26 is located between the casing 20 and the reservoir 22. It is capable of raising the lubricating oil 21 from the casing 20 to the reservoir 22
Implementation Method 2
the overflow device 28 is able to ensure a minimum oil level N1 in the bottom of the housing 20... the overflow device 28 includes, for example, a conduit connecting the reservoir 22 and the bottom of the housing 20
Implementation Method 3
the gearbox 10 includes a heat exchanger 42 positioned between the bottom of the casing 20 and the reservoir 22 on the path of the lift pump 26, and configured to at least partially dissipate heat from the lubricating oil 21 brought up by the pump 26
Implementation Method 4
the reservoir 22 includes cooling fins 46 capable of at least partially dissipating heat dissipated by the lubricating oil 21 contained in the reservoir 22
Implementation Method 5
At least one nozzle 24 is connected below the reservoir 22 and is configured to deliver the lubricating oil 21 from the reservoir 22 to the gear system 14 under the action of gravity
Data Source
Figure 1
AI summary
The present invention relates to a gearbox (10) for a vehicle, in particular for a railway vehicle, comprising: - a gear system (14) including at least two meshed gears (18), - a casing (20) in which the gear system (14) is located, configured to collect a lubricating oil (21) suitable for lubricating the gear system (14), - an oil reservoir (22) located at a height relative to the gear system (14), - at least one nozzle (24) located below the reservoir (22) and configured to deliver the lubricating oil (21) from the reservoir (22) to the gear system (14) under the action of gravity, and - a pump (26) for lifting the lubricating oil (21) from the casing (20) to the reservoir (22).characterized in that it comprises: - an overflow device (28) configured to ensure the flow of excess lubricating oil (21) from the reservoir (22) to the crankcase (20) when the oil level in the reservoir (22) reaches a predefined overflow height (D).