Articulating Drive Shaft Assembly for Large-Angle Torque Transmission
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Solution Overview
Problem
Existing drive shaft arrangements in vehicles, particularly in tilting and off-road vehicles, face inefficiencies and power fluctuations due to the non-linear transmission of torque through large angles, leading to increased friction and wear in constant velocity joints, which affect power balance and require complex suspension systems to accommodate significant wheel displacement and tilt.
Innovation Solution
The axle assembly incorporates a swinging shaft with slidably connected inner and outer portions, utilizing ball splines and bevel gears to maintain equal rotation and variable length, along with universal or constant velocity joints, allowing for large angular displacements and tilting motions without significant power loss or friction changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If constant velocity joints are used to transmit torque through large angles, then power transmission capability is improved, but friction and wear increase significantly
Solution Approach 1:
The patent employs a dynamic articulated shaft design that can change its orientation and length in real-time to match the motion of the wheel hub. The shaft includes articulation joints that allow it to flex and adapt to large angular displacements without relying on high-friction CV joints, thereby maintaining power transmission while reducing energy loss through dynamic adaptation rather than mechanical force multiplication
Solution Approach 2:
The articulated shaft acts as an intermediary element between the fixed drive source and the moving wheel hub. It mediates the transmission of torque by accommodating large angular and linear displacements through its articulated structure, eliminating the need for CV joints that would otherwise be required to handle such extreme motion ranges
2Power
If CV joints operate at large articulation angles, then torque transmission through tilt is improved, but torque reduction due to friction increases
Solution Approach 1:
The articulated shaft dynamically adjusts its configuration to maintain optimal torque transmission paths. The shaft's ability to change angle and length in real-time ensures that torque is transmitted efficiently regardless of the wheel hub's position, maintaining power balance stability even during large tilt angles without relying on friction-prone CV joints
Solution Approach 2:
The system changes the geometric parameters of the drive shaft assembly - specifically the angle and length of the articulated shaft segments - to adapt to varying wheel hub positions. This parametric adaptation allows consistent torque transmission across all operating conditions without the friction-induced power loss that occurs in fixed-geometry CV joint systems
3Reliability
If suspension absorbs bumps through wheel displacement in inclined planes, then suspension capability is improved, but drive shaft length change requirement increases beyond typical plunge capacity
Solution Approach 1:
The drive shaft is segmented into multiple articulated sections that can independently adjust their length and orientation. This segmentation allows the overall shaft length to vary significantly to accommodate large wheel hub displacements while each individual segment maintains a manageable size and structural integrity
Solution Approach 2:
The articulated shaft provides dynamic length adjustment through its telescopic and articulated mechanisms. As the wheel hub moves through large displacements during bump absorption, the shaft dynamically extends or retracts to maintain continuous torque transmission without disconnection or excessive stress, going far beyond the fixed 20mm plunge capacity of conventional CV joints
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 solution ensures consistent torque transmission and power delivery across varying angles, reducing wear and maintaining power balance in vehicles with independent suspension and tilting capabilities, enhancing the efficiency and durability of drive shafts.
Implementation Method 1
utilizing ball splines and bevel gears to maintain equal rotation and variable length
Implementation Method 2
utilizing ball splines and bevel gears to maintain equal rotation and variable length
Data Source
AI summary
An axle arrangement having an outer bevel gear arrangement and an inner bevel gear arrangement. Each bevel gear arrangement allowing large rotation of the axle shaft around a respective swing axis through the bevel gear arrangement, perpendicular to the axle shaft to permit the axle to swing through large angles with negligible impact on transmission of torque. The axle shaft having multiple portions connected in series between the bevel gear arrangements. Between two of the shaft portions is a slidable connection. Between two of the shaft portions is an inner rotatable coupling and between two of the shaft portions is an outer rotatable coupling. Both couplings are stabilised by hinged casings located relative to the bevel gear arrangements with a hinge axis through the rotatable coupling. Each hinge axis is perpendicular to the primary axis of the shaft portion(s) between the rotatable couplings and perpendicular to the respective swing axis.