Integrated Pump Chamber Layout for Leak-Safe Vehicle Drive Units
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Solution Overview
Problem
The existing vehicle drive device configuration is complex due to the external placement of the hydraulic pump, which requires a sealing member and a relief valve to prevent oil leakage, complicating the system.
Innovation Solution
The hydraulic pump's pump chamber is integrated into a partition wall within the case, separating the internal space into two housing chambers, allowing oil to flow only within these chambers and eliminating the need for external sealing members or relief valves, thereby simplifying the configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the hydraulic pump is disposed outside the case with a pump cover joined to the outer surface of the side wall portion, then the pump can be easily accessed and maintained, but the configuration becomes complicated requiring sealing members and relief valves to prevent oil leakage
Solution Approach 1:
The pump chamber is merged with the case structure by forming it as an integrated component of the case body. The partition wall that separates the first and second housing chambers also forms the pump chamber, eliminating the need for separate pump covers and external mounting structures. This integration reduces the number of parts and simplifies the overall configuration while maintaining the pump's functionality.
Solution Approach 2:
The partition wall serves multiple functions: it separates the first housing chamber (housing the rotating electrical machine) from the second housing chamber (housing the transmission gear mechanism and differential gear mechanism), and simultaneously forms the pump chamber for the hydraulic pump. This multi-functionality reduces the total number of components needed in the system.
2Device complexity
If the pump chamber is formed between the side wall portion and pump cover outside the case, then the pump structure is simplified, but sealing members and relief valves are required to prevent oil leakage from the case
Solution Approach 1:
The pump chamber is formed as an integral part of the case structure using the partition wall, eliminating the need for separate pump covers and external sealing structures. By merging the pump chamber with the case, the oil contained in the pump chamber is automatically contained within the case boundaries, removing the need for additional sealing members and relief valves.
3Reliability
If the hydraulic pump is provided with sealing members and relief valves to prevent oil leakage, then oil containment is improved, but the pump configuration becomes complicated
Solution Approach 1:
The pump chamber is merged with the case structure by forming it as an integrated component of the case body. The partition wall that separates the first and second housing chambers also forms the pump chamber, eliminating the need for separate pump covers and external mounting structures. This integration reduces the number of parts and simplifies the overall configuration while maintaining the pump's functionality.
Solution Approach 2:
The partition wall serves multiple functions: it separates the first housing chamber (housing the rotating electrical machine) from the second housing chamber (housing the transmission gear mechanism and differential gear mechanism), and simultaneously forms the pump chamber for the hydraulic pump. This multi-functionality reduces the total number of components needed in the system.
Data Source
AI summary
A vehicle drive device includes: a rotating electrical machine that functions as a driving force source for wheels; an input member drivingly connected to rotating electrical machine; a pair of output members each drivingly connected to wheel; a differential gear mechanism that distributes rotation transmitted from rotating electrical machine to pair of output members; a transmission gear mechanism that drivingly connects input member and differential gear mechanism; a hydraulic pump that includes a pump rotor and chamber housing the pump rotor and that supplies oil to at least the rotating electrical machine; and a case. The case includes a partition portion that separates in an axial direction a first housing chamber housing rotating electrical machine and a second housing chamber housing transmission gear mechanism and differential gear mechanism). Pump chamber is formed in partition wall so as to be located between first and second housing chambers in the axial direction.