Vehicle Drive Layout for Bubble-Free Oil Pump Supply
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Solution Overview
Problem
Existing vehicle drive devices face issues with the production of air bubbles at the oil pump due to insufficient oil supply, which can occur when the oil return speed is slower than the pump's intake speed, especially during vehicle acceleration, deceleration, or turning.
Innovation Solution
The vehicle drive device is configured with a power transmission mechanism that includes a differential gear mechanism disposed on a second axis below a first axis, with the suction port positioned between and below these axes, and a peripheral wall section inclined towards the suction port, ensuring efficient collection and supply of oil to the oil pump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the suction port is disposed at a position directly above the flat bottom surface of the case, then it is possible to avoid exposure of the suction port above the oil level during vehicle acceleration, deceleration, or turning, but the oil supply to the oil pump may not keep up with the pump's intake speed, resulting in air bubble production
Solution Approach 1:
The peripheral wall section is given a specific downward inclination toward the suction port to create a preferential flow path. This local geometric modification directs oil flow from the rotating electric machine region toward the suction port, enhancing oil supply in the critical area without changing the overall suction port position or pump structure.
Solution Approach 2:
The solution introduces a new geometric dimension (the inclination angle of the peripheral wall) to control oil flow. By modifying the wall's slope in the radial direction, the patent creates a flow guidance mechanism that complements the axial positioning, effectively directing oil toward the suction port from multiple spatial directions.
2Productivity
If the oil pump draws in and expels oil at high speed, then cooling efficiency is improved, but the oil return speed may be slower than the pump's intake speed, causing insufficient oil supply and air bubble production
Solution Approach 1:
The downwardly inclined peripheral wall is configured in advance to guide oil flow toward the suction port region. This pre-established flow path ensures that oil is continuously directed toward the suction port before the pump creates a vacuum, preventing air bubble formation and ensuring continuous oil supply during high-speed operation.
Solution Approach 2:
The inclined peripheral wall acts as an intermediary structure between the oil circulation system and the suction port. It mediates the oil flow by directing it toward the suction port, ensuring smooth transition and continuous supply without requiring direct modification of the pump mechanism or oil return channels.
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 configuration effectively prevents the production of air bubbles at the oil pump by ensuring a sufficient oil supply, enhancing the reliability and efficiency of the cooling system.
Implementation Method 1
a portion of an inner surface of the peripheral wall section facing a lower surface of the rotating electric machine is downwardly inclined in the width direction toward the suction port
Implementation Method 2
the outermost gear is disposed so that a direction of rotation at a lower end portion of the outermost gear while the vehicle is moving forward points toward the suction port in the width direction
Data Source
AI summary
A vehicle drive device includes a rotating electric machine disposed on a first axis, an output gear mechanism and an output member disposed on a second axis, and a case that houses these elements. The second axis is disposed below the first axis, a suction port of an oil pump is disposed below the first axis and the second axis and between the first axis and the second axis in a width direction, an outermost gear is disposed so that a direction of rotation at a lower end portion of the outermost gear during forward movement of a vehicle points toward the suction port, and a part of a peripheral wall section of the case that faces a lower surface of the rotating electric machine is inclined downward toward the suction port.