Coaxial Electric Steering Axle Layout for Compact Power Transmission
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Solution Overview
Problem
Existing electrically drivable axles in vehicles have high weight and large installation space requirements, and the efficiency is reduced due to the external feeding of torque and rotational speed into the axle body.
Innovation Solution
The electrically drivable steering axle is designed with the electric motor, transmission, and differential arranged coaxially with the output shafts, eliminating the need for additional spur gears and allowing for a compact, lightweight design that improves efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the electric motor, transmission and differential are arranged in a conventional non-coaxial configuration, then the steering axle can transmit power to the wheels, but the total weight and installation space requirement increase
Solution Approach 1:
The electric motor, transmission, and differential are merged into a single coaxial arrangement where all components share a common central axis. This integration eliminates the need for separate mounting structures and reduces the overall volume occupied by these powertrain components, directly addressing the weight and space constraints.
Solution Approach 2:
The transmission and differential are nested within the same housing space that would conventionally require separate allocations. The coaxial arrangement allows the transmission output shaft to align with the differential input, creating a compact nested structure where components are housed within each other's spatial envelope.
2Loss of energy
If torque and rotational speed are fed into the axle body from outside, then the steering axle can be driven, but the efficiency is reduced
Solution Approach 1:
The electric motor is extracted from the conventional position outside the axle body and integrated directly into the coaxial arrangement. This extraction eliminates the need for external torque feeding mechanisms and reduces the number of power transmission interfaces, thereby minimizing energy losses.
Solution Approach 2:
The coaxial arrangement enables the powertrain components to serve themselves in terms of power transmission. The direct alignment of the motor shaft with the transmission and differential eliminates the need for external power input shafts and reduces the complexity of power feeding into the axle body.
3Power
If additional spur gears are added to connect the motor to the output shafts, then power transmission is enabled, but the weight and installation space increase
Solution Approach 1:
The patent transitions from a conventional lateral power transmission arrangement to a coaxial three-dimensional arrangement. By utilizing the vertical dimension and aligning all power transmission components along a common axis, the patent eliminates the need for additional spur gears that would be required in a planar arrangement, thereby reducing the installation space.
Solution Approach 2:
The coaxial arrangement replaces the need for complex mechanical gear connections with a direct alignment of rotational components. The motor shaft, transmission output shaft, and differential input shaft are all aligned coaxially, eliminating the need for additional spur gears and reducing the mechanical complexity of the power transmission system.
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 arrangement results in a steering axle with reduced weight, minimal installation space, and enhanced efficiency, enabling a simple all-wheel drive in vehicles.
Implementation Method 1
an electric motor (12), in particular a three-phase synchronous or as a three-phase asynchronous machine
Implementation Method 2
a transmission (13), such that a suitable ratio of the torque provided by the electric motor and fed into the transmission, and of the rotational speed provided by the electric motor and fed into the transmission, may be set as required
Implementation Method 3
The fed-in rotational speed and fed-in torque are distributed in the differential to the first and the second output shaft on the basis of a rotational resistance of the first and the second output shaft
Data Source
AI summary
The invention relates to an electrically drivable steering axle (10) having an axle housing (11), an electric motor (12), a transmission (13), a differential (14) with a first output shaft (18) and a second output shaft (18′), a first wheel head (15), a second wheel head (16) and a steering linkage (17, 17′, 17″). The electric motor (12) is drive-connected to the first wheel head (15) and to the second wheel head (16) via the transmission (13) and the differential (14). The steering axle (10) according to the invention is distinguished by the fact that the electric motor (12), the transmission (13), and the differential (14) are arranged coaxially with the first output shaft (18) and the second output shaft (18′). The invention additionally relates to a corresponding vehicle.