Power Transmission Subcase Sealing for Assembly Ease
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Solution Overview
Problem
The existing power transmitting apparatuses for switching between 2-wheel and 4-wheel modes and locking/unlocking differential devices face difficulties in assembling the driving shaft to the sub case due to hermetic sealing, which results in a repulsion force making the assembly challenging.
Innovation Solution
The apparatus includes a sub case with an opening to prevent hermetic sealing, allowing the operational shaft to be inserted and sealed using a first sealing means, reducing the number of parts and improving assembly workability, and features a reversible motor-driven driving shaft for engaging the operational shaft to transmit rotational force, with cam grooves for actuating forks to connect/disconnect and lock/unlock the differential mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sub case is hermetically sealed to protect internal components, then reliability is improved, but assembly difficulty increases due to repulsion force on the driving shaft
Solution Approach 1:
The oil seal is pre-installed on the inner circumferential surface of the opening before the driving shaft is inserted. This preliminary action ensures the seal is in place before assembly, allowing the driving shaft to be inserted without creating repulsion forces that would resist assembly, while still achieving hermetic sealing once assembled.
Solution Approach 2:
The oil seal acts as an intermediary element between the sub case opening and the driving shaft. It provides the hermetic sealing function while being positioned away from the driving shaft's path of insertion, thus preventing direct interference with the assembly process and eliminating repulsion forces.
2Ease of manufacture
If the opening size is increased to facilitate assembly of the operational shaft, then assembly ease is improved, but sealing effectiveness may be compromised
Solution Approach 1:
The oil seal is positioned at a specific location on the inner circumferential surface of the opening, away from the driving shaft. This local placement ensures that the seal provides effective sealing at the critical interface between the sub case and the operational shaft, while the opening itself can be sufficiently large to facilitate easy assembly without compromising sealing effectiveness.
Data Source
AI summary
A power transmitting apparatus for performing switching between 2-wheel and 4-wheel drive modes and locking and unlocking of a differential by an operational shaft can comprise a reversible motor, a driving shaft rotationally driven by the motor and adapted to be engaged by the operational shaft for transmitting a rotational force therebetween, a sub case for containing the motor and the driving shaft therein and mounted on the main case, an opening formed in the sub case and having a size permitting the operational shaft to be inserted and an end face of the driving shaft for engaging an end face of the operational shaft to be exposed, and a first sealing arranged on the inner circumferential surface of the opening at a position away from the driving shaft for sealing off the inside of the sub case with forming a seal between the inner circumferential surface of the opening and the outer circumferential surface of the operational shaft when the operational shaft is engaged with the driving shaft.