Hollow Shaft Drivetrain Coupling for Compact All-Wheel Drive
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Solution Overview
Problem
Existing all-wheel drive vehicle drive trains require a large installation space due to the need for a minimum distance between the gearbox housing and the transfer case housing to accommodate small radial and axial deflections, limiting the compactness and ease of assembly.
Innovation Solution
The output element is a hollow shaft that projects through the second drive train component with radial play, allowing greater radial and axial deflections between the coupling element connections, maintaining only the necessary distance between the first and second drive train components, and featuring a coupling element that can be designed as a cardan shaft or constant velocity joint for efficient torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cardan shaft is used to connect the manual transmission and transfer case, then torque transmission is achieved, but a large minimum distance between the gearbox housing and transfer case housing is required, leading to large installation space
Solution Approach 1:
The coupling element is inserted through the hollow output shaft, with the first connection inside the hollow shaft and the second connection outside. This nested arrangement allows the coupling element to pass through the hollow shaft rather than requiring side-by-side mounting, thereby reducing the distance between the manual transmission and transfer case while maintaining torque transmission capability
Solution Approach 2:
Instead of arranging connections in a planar configuration that requires lateral space, the invention uses the axial dimension by passing the coupling element through the hollow shaft. The first connection is positioned inside the hollow shaft while the second connection is outside, utilizing the through-hole space to achieve compact arrangement and reduce installation footprint
2Area of stationary object
If the distance between the first drive train component and second drive train component is reduced, then installation space is minimized, but the permissible radial and axial deflection between the joints is limited
Solution Approach 1:
The invention changes the geometric parameters of the coupling system by using a coupling element with optimized length and flexibility characteristics. The coupling element is designed with specific dimensional parameters that allow it to accommodate larger radial and axial deflections while maintaining a compact overall distance between the drive train components
3Adaptability or versatility
If the coupling element allows large radial and axial deflection, then adaptability to misalignment is improved, but the angular deflections increase requiring larger connection design
Solution Approach 1:
The coupling element is divided into functional segments: the portion inside the hollow shaft (first connection) and the portion outside (second connection). This segmentation allows each connection to be optimized independently - the first connection handles internal mounting constraints while the second connection accommodates external alignment requirements, simplifying the overall design
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
This design achieves a compact structure with reduced installation space requirements while enabling greater relative movements and easy assembly/disassembly, ensuring reliable torque transmission and minimizing additional loads on surrounding components.
Implementation Method 1
through which the coupling element projects in whole or in part with radial play
Implementation Method 2
The torque transmission from the input member to the output member can be modulated
Implementation Method 3
the constant velocity joints have the advantage that the angular velocities of the input and output sides do not deviate from one another
Data Source
Figure 1
AI summary
The invention relates to a drivetrain for an all-wheel-drive road vehicle comprising a first drivetrain component having a rotatably mounted output element and a second drivetrain component having a rotatably mounted drive element axially relative to the output element. The output element is rotationally fixed to the drive element by a coupling element, which allows deviations from coaxiality of the axes of rotation of the output element and the drive element. The coupling element is connected to the output element by a first connection of its first end and to the drive element, and to the drive element by a second connection of its second end. The output element is a hollow shaft 4 that wholly or partially penetrates the second drivetrain component, is rotatably mounted within the second drivetrain component, and is wholly or partially penetrated by the coupling element with radial clearance 5.The first connection is between the first drive component and the second drive component, and the second connection is located in the area within the second drive component or in the area outside the second drive component on its side facing away from the first drive component.