Propeller Shaft Seal Design Reducing Diameter and Parts
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Solution Overview
Problem
The existing power transmission shafts suffer from increased outside diameter and number of parts due to the use of large-sized boots and boot bands, leading to higher installation time and manufacturing costs, while also compromising impact absorption potential during relative displacements of tubular and shaft members.
Innovation Solution
A power transmission shaft design featuring a male spline joint portion on one shaft member and a female spline joint portion on the other, with a seal member housing and retainer member to prevent foreign matter entry and allow axial sliding movement, eliminating the need for a rubber boot and boot bands, thus reducing diameter and part count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a substantially cylindrical boot is interposed between the rear end of the tubular member and the front end of the shaft member to cover their outer peripheral surfaces, then the spline-connected section is sealed, but the outside diameter of the power transmission shaft enlarges and the number of parts increases
Solution Approach 1:
The invention extracts and eliminates the boot and boot bands from the power transmission shaft structure. Instead of using a separate cylindrical boot component, the patent integrates sealing functionality directly into the spline joint design through the seal ring that fits into the groove formed on the shaft member's outer peripheral surface, thereby reducing the number of parts while maintaining sealing performance
Solution Approach 2:
The invention merges the sealing function with the spline joint structure itself. The seal ring is integrated into the groove formed on the shaft member, combining the structural support function of the shaft with the sealing function, eliminating the need for a separate boot component and reducing overall device complexity
2Reliability
If a substantially cylindrical boot is interposed between the rear end of the tubular member and the front end of the shaft member to cover their outer peripheral surfaces, then the spline-connected section is sealed, but the outside diameter of the power transmission shaft enlarges
Solution Approach 1:
The invention removes the bulky cylindrical boot component that enlarged the outside diameter. By extracting this separate sealing component and replacing it with a compact seal ring integrated into the spline joint groove, the overall outside diameter of the power transmission shaft is reduced while maintaining adequate sealing performance
Solution Approach 2:
The seal ring is nested within the groove formed on the shaft member's outer peripheral surface. This nesting arrangement allows the seal to be housed within the existing structural envelope of the shaft, preventing any increase in outside diameter while still providing effective sealing of the spline-connected section
3Reliability
If boot bands are used to fix both ends of the boot, then the boot is securely retained, but the installation time and manufacturing costs increase
Solution Approach 1:
The invention extracts and eliminates the boot bands from the assembly. The seal ring is retained solely by the groove formed on the shaft member, removing the need for additional fastening components and significantly reducing installation time and manufacturing complexity
Solution Approach 2:
The groove formed on the shaft member provides self-retention for the seal ring through its geometric configuration. The seal ring is held in place by the groove's shape alone, without requiring external fasteners or additional retention mechanisms, thereby simplifying both manufacturing and installation processes
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
The design effectively suppresses the increase in outside diameter and part count, maintaining impact absorption efficiency by enabling smooth axial sliding and preventing seal ring jamming, while reducing manufacturing costs and assembly time.
Implementation Method 1
a seal member (16) configured to prevent entry of foreign matters from an outside into a spline-connected section of the female spline joint portion (13) and the male spline joint portion (19)
Implementation Method 2
when an excessive input load is applied from the transmission to the tubular member, for instance, during a vehicle collision, an impact can be absorbed and reduced by virtue of relative movement of the tubular member toward the shaft member
Data Source
AI summary
In a power transmission shaft including a rear-side shaft having a male spline joint portion formed on the outer periphery of a front end of the rear-side shaft and a tubular front-side shaft having a female spline joint portion formed on the inner periphery of a rear end of the tubular front-side shaft, a seal ring is housed in a seal housing groove configured at the rear end of the tubular front-side shaft. The seal ring is interposed between an outer peripheral seal surface of the rear-side shaft and an inner peripheral surface of the seal housing groove with a compressive deformation. Additionally, the seal ring is sandwiched and retained between the inside wall surface of the seal housing groove and the inside end face of a disk-shaped retainer part of a retainer press-fitted to the rear end of the tubular front-side shaft.