Gear Lubrication Gutter Layout for Centrifugal Oil Scattering
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Solution Overview
Problem
In vehicle drive-force transmitting apparatuses, the increased sliding speed and pressure on gear tooth surfaces lead to elevated temperatures, causing damage like 'pitting', and existing lubrication mechanisms struggle to provide a sufficient oil supply to these surfaces due to oil scattering from centrifugal force during forward running.
Innovation Solution
A lubrication mechanism featuring a gutter with a flow-direction changing rib and guide rib, positioned to direct oil towards the meshing region, ensuring efficient oil supply to gear tooth surfaces, and a recessed portion to prevent oil from sticking to the gutter's lower surface, allowing for effective lubrication during forward running while minimizing oil flow during reverse running.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If oil is scooped up by a scooping-up gear during forward running, then the gear is rotated and oil is moved along the side surface of the tooth portion, but the oil is scattered radially outwardly from the gear due to centrifugal force, making it difficult to provide a sufficient amount or rate of supply of oil to the tooth surface
Solution Approach 1:
A gutter is introduced as an intermediary component to intercept and redirect the oil flow. The gutter receives oil that would otherwise be scattered by centrifugal force and guides it to the tooth surface, effectively mediating between the scooping-up gear and the gear tooth surface to ensure adequate lubrication.
Solution Approach 2:
The gutter extends in the axial direction of the gear, creating a new dimensional pathway for oil delivery. By positioning the gutter's end at a specific axial location opposite to the upstream side portion of the gear, the system utilizes the axial dimension to deliver oil against the radial outward scattering tendency.
2Reliability
If the gutter end is positioned to optimize oil supply to the meshing region, then effective lubrication is achieved, but the gutter structure becomes more complex with flow-direction changing ribs and guide ribs
Solution Approach 1:
The gutter structure is segmented into functional zones using ribs: a guide rib that directs oil flow toward the gutter end, and a flow-direction changing rib that redirects oil onto the gear tooth surface. This segmentation allows each rib to perform a specific function, achieving reliable lubrication through divided, specialized components rather than a monolithic complex structure.
3Quantity of substance
If the gutter receives oil during forward running, then oil supply to tooth surfaces is improved, but stirring resistance increases during reverse running
Solution Approach 1:
The gutter system dynamically adapts to different operating conditions. During forward running, the gutter receives and directs oil effectively. During reverse running, the relative motion between the gutter and gear causes oil to be thrown against the flow-direction changing rib, which redirects it back into the gutter, automatically adjusting the lubrication pattern to minimize energy loss from excessive stirring.
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
The mechanism effectively supplies oil to gear tooth surfaces at a sufficient rate, reducing temperature-related damage and maintaining optimal lubrication, while minimizing stirring resistance during reverse running by controlling oil flow.
Implementation Method 1
a flow-direction changing rib with which the received oil is to be collided whereby a flow direction of the received oil is changed to a direction toward the end of the gutter
Implementation Method 2
oil scooped up, for example, during forward running of the vehicle by which the first and second gears are rotated in respective directions
Data Source
AI summary
A lubrication mechanism for a vehicle drive-force transmitting apparatus including; first and second gears meshing with each other in a meshing region; and a casing storing therein the first and second gears. The lubrication mechanism includes a gutter that extends from an inner wall surface such that oil is received in the gutter and is then dropped from an end of the gutter. The gutter includes a flow-direction changing rib with which the received oil is to be collided whereby a flow direction of the received oil is changed to a direction toward the end of the gutter. The end of the gutter is located on upper side of the meshing region, between first and second vertical planes containing respective first and second axes about which the first and second gears to be rotated, and is located between opposite ends of the meshing region.