Power Transmission Unit Drainage and Locking Device Design
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Solution Overview
Problem
Conventional power transmission units in hybrid vehicles allow foreign matter such as water and dust to enter the housing, leading to malfunction and deterioration of the braking means, particularly the one-way clutch or brake, due to the lack of sealing between the engine block and transmission housing.
Innovation Solution
A power transmission unit design featuring a locking device with a fixed member and a movable member, where a through hole is strategically positioned at the lowest portion of the housing outside the locking device's region to drain foreign matter, and the fixed member is made with enhanced elasticity and a buffer portion to absorb torsional loads, preventing adhesion and damage from foreign intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a through hole is formed on the housing to drain water, then water drainage function is improved, but foreign matter such as dust can enter the housing causing malfunction of the braking means
Solution Approach 1:
The through hole is positioned at a specific location on the housing that is axially outside the locking device region. This localized placement allows water drainage while preventing foreign matter from entering the locking device area, as the hole is situated in a region where foreign matter intrusion is less likely to occur.
Solution Approach 2:
The locking device region acts as an intermediary barrier. By positioning the through hole axially outside this region, the design uses the locking device's spatial boundary as a protective mediator, allowing water to drain while blocking foreign matter from reaching the locking device components.
2Reliability
If the fixed member is made with higher elasticity to absorb torsional loads, then durability is improved, but the structural rigidity is reduced
Solution Approach 1:
The fixed member is designed with enhanced elasticity by modifying its material properties or structural parameters. This allows the fixed member to deform elastically under torsional loads, absorbing impact and excessive torque while maintaining sufficient structural integrity for normal operation.
Solution Approach 2:
The elastic fixed member acts as a pre-designed cushioning element that absorbs torsional shocks and impacts before they can damage the locking device. The enhanced elasticity provides a buffer zone that protects the system from sudden torque variations and external impacts.
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
Prevents malfunction of the locking device by excluding foreign matter and enhances durability and reliability by absorbing impact and excessive torque, thereby maintaining the power transmission unit's performance.
Implementation Method 1
The fixed member is formed in a manner to have higher elasticity than that of other members of the locking device. The buffer portion is formed on at least a portion of the fixed member to enhance torsional elasticity higher than that of remaining portion.
Data Source
AI summary
A power transmission unit for preventing malfunction and deterioration in durability of a locking device arranged in a housing by preventing the ingress of foreign matters into the locking device. In the power transmission unit, a one-way brake 10 for selectively stopping a rotation of an output shaft 1a of an engine 1 is disposed between the housing 11 of a transmission mechanism and an engine block 1b. A fixed member 10a is fixed to the housing 11 or to the engine block 1b, and a movable member 10b is attached to the output shaft 1a. A through hole 21 is formed on the housing at a vertically lowest portion and axially outside of a region where the one-way brake 10 is situated, so as to provide a communication between an inner space and an outer space of the housing 11.