Vehicle Transmission Differential Oil Level Control
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Solution Overview
Problem
In vehicle transmissions with a differential unit in a case, hydraulic oil tends to flow back into the differential chamber, increasing resistance during rotation, as it is not efficiently discharged from the ring gear to the oil pan chamber.
Innovation Solution
A vehicle transmission design featuring a differential separation member with a communication portion upstream of the ring gear's rotation direction and a wall member that guides oil away from the differential chamber, preventing it from flowing back, thus maintaining a low oil level and reducing stirring resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ring gear meshes with the final gear in the conventional design, then power transmission is achieved, but hydraulic oil is trapped in the meshing portion and flows back into the differential chamber, increasing stirring resistance
Solution Approach 1:
The differential chamber is segmented from the oil pan chamber by a differential separation member (reservoir plate) with a communication portion. This segmentation allows the oil level in the differential chamber to be controlled independently, maintaining it below the ring gear to prevent oil trapping and reduce stirring resistance while still allowing power transmission through the meshing gears.
Solution Approach 2:
The communication portion formed by the cutout in the upper rib acts as an intermediary structure that regulates oil flow between the differential chamber and oil pan chamber. It enables excess oil to drain from the differential chamber while preventing oil from the oil pan chamber from entering, thus controlling the oil level to minimize stirring resistance during ring gear rotation.
2Loss of energy
If the oil level in the differential chamber is reduced to minimize stirring resistance, then energy loss is reduced, but oil may not be sufficient to lubricate the meshing gears
Solution Approach 1:
The communication portion maintains a continuous controlled connection between the differential chamber and oil pan chamber. This allows oil to continuously drain from the differential chamber when the level rises, preventing excessive oil accumulation and stirring resistance, while ensuring that sufficient oil remains in the differential chamber to continuously lubricate the meshing gears.
Solution Approach 2:
The upper rib structure with its cutout creates a localized oil level control zone. The communication portion is positioned at a specific height to create an optimal oil level in the differential chamber - high enough to ensure gear lubrication but low enough to prevent oil from reaching the ring gear meshing portion, thus balancing lubrication needs with resistance reduction.
3Quantity of substance
If a weir member is used to separate the differential chamber from the oil pan chamber, then oil level control is achieved, but the structure becomes more complex and oil may still flow back through the meshing gears
Solution Approach 1:
The upper rib structure serves multiple functions: it provides structural support for the differential chamber, creates the communication portion for oil level control, and prevents oil backflow into the differential chamber. By integrating these functions into a single structural element rather than adding separate components, the design achieves effective oil level control without significantly increasing structural complexity.
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
Efficient discharge of oil from the differential chamber, preventing its flow back into the chamber, which reduces the oil level and minimizes the stirring resistance of the ring gear, enhancing the transmission's efficiency.
Implementation Method 1
the hydraulic oil in the differential chamber 5 is discharged into the oil pan chamber 3 by rotation of a ring gear 14 of the differential mechanism 10
Implementation Method 2
a communication portion, which is formed in an upper part of the differential separation member, and is located on an upstream side of the opening in a rotation direction of the ring gear during forward traveling, and which discharges the oil from the differential chamber
Data Source
AI summary
A vehicle transmission including a rotatable input shaft connected to a driving source; a countershaft parallel to the input shaft; a differential unit below the countershaft, to which rotation is input from the countershaft, and coupled to right and left wheels; a case member containing the input shaft, countershaft, and the differential unit; a differential chamber disposed in the case member, contains the differential unit, and is separated from an oil storage chamber; and a differential separation member separating the differential chamber from the storage chamber, and formed along the differential unit ring gear, which meshes with an output gear of the countershaft. The differential separation member has an opening so the output gear can mesh with the ring gear, a communication portion, formed in an upper part of the differential separation member, and located on an upstream side of the opening in a rotation direction of the ring gear during forward traveling, discharges oil from the differential chamber, and a wall member on a side of an output gear meshing portion and the ring gear with respect to the communication portion, and contacts the differential separation member outer surface.