Internal Combustion Engine Compact Shaft Layout
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Solution Overview
Problem
Existing internal combustion engine designs face space utilization challenges due to parallel alignment of the crankshaft, balancer shaft, and oil pump driving shaft, restricting the disposition of auxiliary machines and other components, which hinders the engine's compactness.
Innovation Solution
The engine incorporates a balancer shaft and oil pump driving shaft disposed in a neighboring relationship, with the balancer shaft supported by both the crankcase and case cover, and an oil pump with a smaller diameter pump driving gear that meshes with the balancer driven gear, allowing for closer placement and optimizing space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the crankshaft, balancer shaft, and oil pump driving shaft are disposed parallel to each other in the lateral direction, then the structure is simple and easy to manufacture, but space utilization is restricted and the engine cannot be made compact
Solution Approach 1:
The patent changes the spatial arrangement of shafts from a single-plane parallel configuration to a multi-dimensional layout where the balancer shaft and oil pump driving shaft are positioned at different heights (vertical dimension) and connected through gear meshing. This dimensional change allows closer positioning of components while maintaining functional independence, thereby improving engine compactness without excessive complexity.
2Adaptability or versatility
If the balancer shaft is supported by both crankcase and case cover, then the balancer shaft can be positioned more flexibly, but the support structure becomes more complex
Solution Approach 1:
The support structure for the balancer shaft is segmented into two independent parts: a case side supporting portion formed on the crankcase and a cover side supporting portion formed on the case cover. This segmentation allows each support element to be independently designed and positioned, providing flexible shaft positioning while keeping each support structure relatively simple. The two supports work together to achieve the desired flexibility without creating excessive complexity in any single component.
Data Source
AI summary
An internal combustion engine 1 includes a crankcase 10, a case cover 20R which covers a side of the crankcase 10, a crankshaft 11 and a balancer shaft 61, a balancer 6 having a balancer driven gear 62 and a balance weight 60 provided on the balancer driven gear 62 and acted upon and driven by driving force of the crankshaft 11 to rotate, and an oil pump 8 accommodated in the crankcase 10 and having an oil pump driving shaft 81 disposed in parallel to the crankshaft 11 and the balancer shaft 61. The oil pump 8 includes a pump driven gear 82. The balancer 6 has a pump driving gear 63 which has a smaller diameter than the balancer driven gear 62 and rotates together with the balancer driven gear 62. The pump driving gear 63 meshes with the pump driven gear 82. The oil pump driving shaft 81 is disposed within an area of rotation of the balance weight 60 as viewed in an axial direction thereof. Thus, the balancer shaft and the oil pump driving shaft can be disposed next to each other and the internal combustion engine can be made compact.