Compact Final Drive Axle with Nested Radial Bearings
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Solution Overview
Problem
Existing axle drives for motor vehicles require large installation space due to the arrangement of ring gears and bearings, which complicates the mounting and compactness of the transmission housing.
Innovation Solution
The axle drive features a unique arrangement of input and output shafts with ring gears mounted using radial bearings on bearing projections, allowing for a tandem or X-arrangement of the bearings, which reduces the space requirement by eliminating the need for a hypoid offset and enabling a compact configuration of the transmission housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ring gears are mounted using conventional bearing arrangements, then reliable torque transmission is achieved, but large installation space is required
Solution Approach 1:
The patent implements a nested bearing arrangement where one radial bearing is positioned inside the outer diameter of another radial bearing. The inner bearing supports the ring gear at one location while the outer bearing provides additional support at a different location along the same radius. This nesting configuration allows both bearings to occupy the same radial space rather than requiring separate radial zones, thereby reducing the overall installation space while maintaining reliable torque transmission through dual bearing support.
2Adaptability or versatility
If hypoid offset is used to arrange input and output shafts at angles, then shaft orientation flexibility is improved, but installation space requirement increases
Solution Approach 1:
The patent resolves the shaft orientation problem by transitioning from a hypoid offset arrangement (which requires axial displacement and increases installation space) to a configuration where both input and output shafts are arranged coaxially. The angular relationship between shafts is achieved not through radial offset but through the perpendicular arrangement of the ring gear planes, effectively moving the orientation flexibility to a different dimensional approach. This coaxial arrangement with perpendicular ring gear planes reduces the installation space requirement while maintaining the desired shaft orientation flexibility.
3Reliability
If multiple radial bearings are arranged in tandem or X configuration, then ring gear support reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines the functions of multiple radial bearings by arranging them in a nested configuration where one bearing is positioned within the outer diameter of another. This merging of spatial occupancy allows both bearings to support the ring gear simultaneously without requiring separate mounting locations that would increase device complexity. The nested arrangement simplifies the overall bearing support structure while maintaining the reliability benefits of multiple bearing contacts.
Data Source
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AI summary
The invention relates to a final drive (1) for a motor vehicle, comprising a first input shaft (2), a second input shaft (4), a first output shaft (7), and a second output shaft (10), wherein the first input shaft (2) is permanently coupled to the first output shaft (7) by means of a first bevel-gear transmission (6) and the second input shaft (4) is permanently coupled to the second output shaft (10) by means of a second bevel-gear transmission (9). According to the invention, the first input shaft (2) and the second input shaft (4) are arranged coaxial to each other and the first output shaft (7) and the second output shaft (10) extend from the respective bevel-gear transmissions (6, 9) in opposite directions, wherein an axis plane (21) contains the axes of rotation (17, 18) of the input shafts (2, 4) and a plane perpendicular to the axis plane (21) includes an angle of at least 75° and at most 90° with each of the axes of rotation (19, 20) of the output shafts (7, 10), and that a first bevel gear (13) of the first bevel-gear transmission (6), which first bevel gear is rigidly connected to the first output shaft (7), and/or a second bevel gear (15) of the second bevel-gear transmission (9), which second bevel gear is rigidly connected to the second output shaft (10), is mounted in a drive housing (16) of the final drive (1) in each case by means of a first radial bearing (43) and a second radial bearing (44), which are arranged in tandem arrangement or in X arrangement to each other or are designed as a fixed bearing and as a floating bearing.