Spur Gear Transmission Cooling via Enveloping Wall Channels
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Solution Overview
Problem
High-speed transmissions, such as turbo transmissions, experience significant power losses due to the turbulence of the air-oil mixture within the transmission housing, and existing solutions that aim to reduce these losses through vacuum creation and encapsulation come with high costs and inefficiencies.
Innovation Solution
A spur gear design featuring an enveloping wall that partially encloses the gears with annular gaps, allowing for a separate coolant flow through cooling channels to efficiently dissipate heat, reducing the need for excessive lubricant flow and minimizing power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If vacuum pumps are used to create strong vacuum inside transmission housing, then power losses due to turbulence are reduced, but device complexity and energy consumption increase
Solution Approach 1:
The invention extracts the harmful air-oil mixture from the gear enclosure by providing openings that allow it to escape to the outside environment, eliminating the need for vacuum pumps while still reducing turbulence-related power losses
Solution Approach 2:
The patent introduces an intermediary fluid (inert gas or vapor) that fills the space between the gears and housing, acting as a mediator that reduces turbulence and power losses without requiring active vacuum systems
2Temperature
If lubricant flow is increased to cool the gears, then temperature stress on components is reduced, but power losses increase
Solution Approach 1:
The invention extracts excess heat through the annular gaps between gears and housing, allowing heat-carrying fluid to escape and new cool fluid to enter, thereby reducing the need for high lubricant flow rates while maintaining effective cooling
Solution Approach 2:
The patent segments the cooling function from the lubrication function by using separate fluid paths - lubricant for lubrication and a separate coolant flow through annular gaps for heat dissipation, allowing optimization of each function independently
3Loss of energy
If encapsulation with outer wall is implemented, then vacuum creation is improved, but manufacturing complexity and cost increase
Solution Approach 1:
Instead of complete encapsulation, the patent applies partial enclosure with the outer wall extending only partially around the gears, providing sufficient vacuum creation and turbulence reduction while significantly simplifying manufacturing compared to full encapsulation
Solution Approach 2:
The outer wall serves multiple functions simultaneously: it creates the vacuum environment, reduces turbulence, and provides structural support, eliminating the need for separate components and simplifying manufacturing
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 effectively reduces power losses by utilizing a larger coolant flow to manage heat dissipation, allowing for a smaller lubricant flow, thereby lowering temperature stress on components and minimizing energy consumption.
Implementation Method 1
a separate coolant flow through cooling channels to efficiently dissipate heat
Implementation Method 2
a lubrication device configured to direct a lubricant flow into the teeth of the spur gears
Data Source
Figure 1
Figure 2
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AI summary
The invention relates to a spur gear transmission having at least two toothed spur gears, the teeth of which intermesh and which can each be rotated about an axis of rotation; having an enveloping wall which encloses the two spur gears in the circumferential direction and in the direction of the axis of rotation; the enveloping wall having an internal contour which is matched to the external diameters of the spur gears in such a way that two annular gaps result which merge into each other between the enveloping wall and the spur gears, in each case an annular gap being arranged at least substantially concentrically in relation to a respective axis of rotation; and having a lubricating device which is set up to lead a stream of lubricant into the teeth of the spur gears. The spur gear transmission according to the invention is characterized in that in addition a cooling device is provided, which is set up to lead a stream of coolant through one or more cooling channels running within the enveloping wall and/or on the outside along the enveloping wall.