Power Transmission Support Structure for Drag Torque Reduction
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Solution Overview
Problem
In power transmission devices, excessive hydraulic oil between frictional engaging plates can generate large drag torque when the brake is disengaged, leading to significant energy loss.
Innovation Solution
The design includes a ring-shaped wall portion with a through hole that directs hydraulic oil away from the frictional engaging plates, using an oil collecting portion and a tilted through hole to discharge oil outside the drum portion, reducing the likelihood of oil flowing back into the frictional engaging plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic oil is supplied to the bearing for lubrication and cooling, then the bearing can operate smoothly, but hydraulic oil may flow into the space between frictional engaging plates and generate large drag torque when the brake is disengaged
Solution Approach 1:
The support is divided into multiple functional portions: a ring-shaped wall portion, a drum portion, and a boss portion. The ring-shaped wall portion includes a through hole that segments the hydraulic oil flow path, directing oil away from the frictional engaging plates while maintaining supply to the bearing.
Solution Approach 2:
The through hole in the ring-shaped wall portion acts as an intermediary structure that mediates between the hydraulic oil supply to the bearing and the prevention of oil infiltration into the frictional engaging plates space. It provides a controlled passage that directs oil flow appropriately.
2Loss of energy
If the through hole opening facing the first space is located radially inward of the frictional engaging plates, then hydraulic oil can be discharged to the second space effectively, but the structure becomes more complex
Solution Approach 1:
The support structure merges multiple functions into a single component: it provides bearing support through the boss portion, manages hydraulic oil flow through the through hole in the ring-shaped wall portion, and structurally connects the drum portion and other components. This integration reduces the need for separate oil management components.
Solution Approach 2:
The ring-shaped wall portion with the through hole serves multiple purposes: it provides structural support, controls hydraulic oil flow direction, prevents oil infiltration into the frictional engaging plates space, and maintains the mechanical connection between components. This multi-functionality reduces overall system complexity.
Data Source
AI summary
A power transmission device including a transmission, a case housing the transmission, a brake including a plurality of frictional engaging plates and a piston for pressing the frictional engaging plates and configured to non-rotatably hold any one of rotation elements of the transmission stationary to the case, and a support fixed to the case and including a ring-shaped wall portion extending in a radial direction of the transmission, a drum portion extending from the ring-shaped wall portion in an axial direction of the transmission and non-rotatably supporting a part of the frictional engaging plates, and a boss portion extending from the ring-shaped wall portion toward a side opposite to the frictional engaging plates in the axial direction and rotatably supporting another rotation element of the power transmission device.