Vehicle Drive Device Ring Gear Fixation for Lubrication Stability
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Solution Overview
Problem
The lubrication performance of a vehicle drive device's power transmission mechanism becomes unstable due to air flow generated by the rotation of the planetary gear device during series hybrid mode, leading to impaired lubrication.
Innovation Solution
The vehicle drive device includes a housing case with a non-rotatably held ring gear of the planetary gear device, which prevents air flow from affecting the oil distribution to the power transmission mechanism, ensuring stable lubrication by positioning the ring gear non-rotatably within the housing case and arranging the power transmission mechanism to be partially immersed in oil, thus stabilizing the oil distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the planetary gear device is integrally rotated during series hybrid mode, then the generator can be rotationally driven to generate electric power, but the distributed state of the oil for the power transmission mechanism becomes unstable due to air flow generated by the rotation, impairing lubrication performance
Solution Approach 1:
The planetary gear device is divided into rotating components (sun gear, carrier) and a non-rotating component (ring gear). The ring gear is fixed to the housing case to prevent it from rotating, thereby eliminating the air flow problem while still allowing the generator to be driven through the sun gear and carrier rotation.
Solution Approach 2:
The harmful rotational motion of the ring gear is extracted and eliminated from the system. By fixing the ring gear to the housing case, the source of problematic air flow is removed while the power transmission path through the sun gear and carrier remains intact for generator operation.
2Reliability
If the ring gear is non-rotatably held by the housing case, then air flow interference is eliminated and lubrication becomes stable, but the structural complexity of the housing case increases
Solution Approach 1:
The ring gear is merged with the housing case through direct fixing, creating a unified structure. This eliminates the need for separate support mechanisms or complex mounting arrangements, as the housing case itself serves as the non-rotating support for the ring gear.
Solution Approach 2:
The housing case is given multiple functions: it serves as both the structural enclosure and the non-rotating support for the ring gear. This multi-functionality reduces the need for additional components, thereby simplifying the overall structure despite the added constraint.
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 maintains stable lubrication performance for the power transmission mechanism by preventing air flow interference and ensuring consistent oil distribution, even during integral rotation of the planetary gear device.
Implementation Method 1
a planetary gear device (24), with a sun gear (24s) and a carrier (24c) rotationally driven by an engine (16) and a ring gear (24r) non-rotatably held by a housing case (60), to transmit a rotation of the engine (16) to the generator (28)
Implementation Method 2
oil supplied by an oil pump, scooping-up, etc. is distributed to meshing portions, bearings, etc. of the power transmission mechanism for lubrication
Data Source
AI summary
A vehicle drive device including a generator rotationally driven to generate electric power by an engine via a planetary gear device, an electric motor operated by using an electric energy obtained by the generator, and a power transmission mechanism transmitting an output of the electric motor to wheels comprises: a housing case including a first housing space; and a lubricating device distributing an oil at least to the power transmission mechanism in the first housing space for lubrication. The planetary gear device and the power transmission mechanism are housed in the first housing space and a sun gear and a carrier of the planetary gear device are coupled to one and the other of the engine and the generator respectively, while a ring gear of the planetary gear device is non-rotatably held by the housing case.