Vehicle Drive Unit Shaft Coupling With Bearing-Based Centering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing drive units for vehicles require precise assembly sequences and additional centering elements to align the rotor and transmission shafts, limiting flexibility and achieving only moderate running accuracy.
Innovation Solution
The drive unit design separates the rotor and transmission shafts, allowing them to be assembled independently, with a third rolling bearing at their transition to ensure rotational fixation and centering, eliminating the need for additional centering elements and enhancing coaxial tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the rotor shaft and transmission shaft are integrated and double-mounted, then the assembly structure is compact, but the assembly sequence becomes complex and requires precise coordination
Solution Approach 1:
The patent divides the previously integrated rotor shaft and transmission shaft into two separate components. The rotor shaft is mounted in the motor housing while the transmission shaft is mounted in the transmission housing, allowing independent assembly of each shaft in its respective housing before final coupling. This segmentation eliminates the need for complex double-mounting procedures while maintaining compact overall structure through the coupling mechanism between the two shafts.
2Manufacturing precision
If additional centering elements are used to guide the shafts, then the centering precision is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent employs the third rolling bearing to perform the dual function of supporting radial forces and providing centering guidance for the rotor shaft and transmission shaft. The bearing's inner raceway naturally guides the shafts into coaxial alignment during assembly without requiring separate centering elements. This self-service approach achieves high centering precision while eliminating additional centering components, thereby reducing device complexity and manufacturing cost.
3Adaptability or versatility
If the rotor shaft and transmission shaft are configured separately, then the flexibility in material selection and machining is improved, but the assembly coordination becomes more difficult
Solution Approach 1:
The third rolling bearing acts as an intermediary element that couples the separately configured rotor shaft and transmission shaft in a rotationally fixed manner. This intermediary component facilitates the connection between the two independently designed shafts, allowing each shaft to be manufactured from optimal materials and with optimal geometries while the bearing ensures proper alignment and coordination during assembly. The bearing's standardized interface simplifies the assembly process despite the separate configurations.
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 allows for greater assembly flexibility, improved running accuracy, and reduced material and manufacturing costs by enabling separate machining and material selection for the shafts, while supporting axial and radial forces effectively.
Implementation Method 1
a third rolling bearing which comprises an inner bearing ring is disposed at the (axial) transition between the transmission shaft and the rotor shaft, wherein the inner bearing ring abuts the rotor shaft and the transmission shaft with its inner surface
Implementation Method 2
The transmission shaft is rotatably mounted in a first housing section by means of a first rolling bearing
Implementation Method 3
the rotor shaft is rotatably mounted in a second housing section by means of a second rolling bearing
Data Source
AI summary
A drive unit (10) for a vehicle including an electric machine (12) having a rotor shaft (14) and a transmission (16) with a transmission shaft (18). The transmission shaft (18) is rotatably mounted in a first housing section (22) with a first rolling bearing (20) and the rotor shaft (14) is rotatably mounted in a second housing section (26) with a rolling second bearing (24). The transmission shaft (18) and the rotor shaft (14) are coupled to one another in a rotationally fixed manner. A third rolling bearing (28), which has an inner bearing ring (30), is arranged at the transition between the transmission shaft (18) and the rotor shaft (14), The inner bearing ring (30) is in contact with the rotor shaft (14) and the transmission shaft (18) with its inner surface (32).