Front Transmission Shaft Sealing in Hybrid Work Vehicle Gearcases
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Solution Overview
Problem
Existing work vehicles with hybrid transmissions face challenges in preventing the flow of lubricating oil between the electric and gear transmission chambers without altering the shape of the transmission case, especially when the front transmission shaft extends frontward.
Innovation Solution
A tubular member forms a power transmission path through the electric transmission chamber, partitioned from it, with O-rings at support holes to seal gaps and prevent lubricating oil flow, allowing the front transmission shaft to extend frontward without changing the transmission case shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the front transmission shaft is disposed to pass through the electric transmission chamber, then the transmission case shape does not need to be changed, but lubricating oil flows between the electric transmission chamber and the gear transmission chamber
Solution Approach 1:
The patent divides the transmission case into two separate chambers (electric transmission chamber and gear transmission chamber) with a partition wall, and routes the front transmission shaft through a tubular member that passes through the partition wall. This segmentation allows the shaft to extend through the electric transmission chamber without compromising the seal between chambers, as the tubular member creates a dedicated sealed pathway.
Solution Approach 2:
The patent introduces a tubular member as an intermediary element between the front transmission shaft and the partition wall. This tubular member acts as a mediator that allows the shaft to pass through while maintaining the seal, as the oil seal is installed between the tubular member and the partition wall rather than directly between the shaft and partition wall.
2Reliability
If an oil seal is interposed between the partition wall and the front transmission shaft, then lubricating oil flow is reduced, but it cannot be completely prevented
Solution Approach 1:
The tubular member serves as an intermediary that provides a sealed pathway for the front transmission shaft. The oil seal is installed between the tubular member and the partition wall, creating a double-seal effect that more effectively prevents lubricating oil flow compared to a single seal directly on the shaft.
Solution Approach 2:
The patent segments the sealing function into two parts: the partition wall separates the chambers, and the tubular member with its own oil seal provides additional sealing at the shaft penetration point. This segmented approach to sealing more effectively prevents lubricating oil loss.
3Ease of operation
If the front transmission shaft extends outside the transmission case, then a power transmission path must be provided outside the transmission case, but this changes the transmission case shape
Solution Approach 1:
The patent resolves the spatial conflict by changing the dimensionality of the power transmission path. Instead of routing the shaft horizontally outside the transmission case, the shaft is routed vertically through the partition wall via the tubular member, utilizing the vertical dimension to maintain the external shape of the transmission case.
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 lubricating oil flow between transmission chambers while maintaining the transmission case's original shape, ensuring efficient power transmission without additional structural modifications.
Implementation Method 1
O-rings are interposed in support holes of the partition wall and a wall portion forming the electric transmission chamber. The O-rings seal gaps between the tubular member and the partition wall, preventing lubricating oil from flowing between the electric transmission chamber and the gear transmission chamber.
Data Source
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AI summary
A work vehicle includes a transmission case (11) that forms an electric transmission chamber (16) and a gear transmission chamber (17) located rearward of the electric transmission chamber (16), the gear transmission chamber (17) and the electric transmission chamber (16) being partitioned from each other. A front transmission shaft (70) is provided that extends frontward from the gear transmission section and transmits motive power to a front travel device. The transmission case (11) includes a tubular member (73) that forms a power transmission path (74) that passes through the electric transmission chamber (16) in the front-rear direction while being partitioned from the electric transmission chamber (16). The front transmission shaft (70) passes through the power transmission path (74).