Offset Oil Passages in Reduction Gear Lubrication
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Solution Overview
Problem
The conventional lubrication structure for reduction gears requires a large case in the up-down direction to accommodate overlapping oil passages, making it difficult to install a spare tire or on-board battery due to the difference in scooping capacity between the first and second pairs of reduction gears.
Innovation Solution
The lubrication structure offsets the first and second pairs of reduction gears in the rotation axis line direction, with non-overlapping catch tanks and oil passages, allowing for a more compact design by positioning the catch tank to avoid vertical overlap and utilizing offset oil passages to guide lubrication oil to a central catch tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the first and second oil passages are arranged to be overlapped with each other forming a double deck structure, then the lubrication oil can be guided from both reduction gear pairs to the catch tank, but the size of the case in the up-down direction becomes large, interfering with the installation of spare tire or on-board battery
Solution Approach 1:
The patent transitions from a vertical stacked arrangement (double deck overlapping oil passages) to a horizontal side-by-side arrangement (offset oil passages). The first oil passage is positioned at a first position and the second oil passage is positioned at a second position offset in the rotation axis line direction, eliminating vertical overlap and reducing the up-down dimension of the case.
2Reliability
If the catch tank is arranged at an upper portion relative to the reduction gears, then the lubrication oil can be supplied effectively, but the case size in the up-down direction becomes large, making it difficult to assure space for spare tire or on-board battery
Solution Approach 1:
The catch tank is repositioned from an upper location (vertical arrangement) to a location adjacent to the oil passages in the rotation axis line direction (horizontal arrangement). This dimensional change maintains the lubrication function while reducing the up-down dimension of the case, creating space for spare tire or on-board battery installation.
3Productivity
If the first and second pairs of reduction gears are arranged with different rotation speeds, then the gear reduction function is achieved, but the oil passages require different positions to accommodate the scooping capacity difference, complicating the lubrication structure
Solution Approach 1:
The patent assigns different positions to the first and second oil passages according to the specific requirements of each reduction gear pair. The first oil passage is positioned to accommodate the first driven gear's scooping capacity, while the second oil passage is positioned to accommodate the second driven gear's scooping capacity. This localized optimization simplifies the overall structure by eliminating the need for a complex overlapping double deck arrangement.
Data Source
AI summary
A lubricating structure for a reduction gear includes a catch tank for holding a part of lubricating oil which is held on the bottom part of a transaxle case and which is supplied, by being scooped up, to each portion to be lubricated, a first oil passage provided within the transaxle case and guiding lubricating oil, which has been scooped up by a first driven gear, to the catch tank and a second oil passage provided within the transaxle case so as to be displaced from the first oil passage in an axial direction relative to the case and guiding lubricating oil, which has been scooped up by a second driven gear, to the catch tank.