Electric Drive Axle PTO Shifting for Independent Speed Control
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Solution Overview
Problem
Commercial vehicles with electric drive axles require separate power supplies and thermal management for additional electric motors driving power take-off, leading to increased costs and space requirements, and existing solutions do not allow independent rotational speed control of power take-off.
Innovation Solution
An electric drive axle with a double shift element that couples the vehicle drive system to a power take-off interface, enabling variable-speed operation and independent engagement/disengagement of power take-off, and an additional shift element for independent coupling/decoupling, allowing power take-off operation regardless of vehicle drive system rotational speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate electric motor is provided to drive the power take-off, then the power take-off can be driven independently, but additional power supply, power electronics unit, and thermal management systems are required, increasing cost and installation space
Solution Approach 1:
The patent combines the power take-off drive function with the existing electric vehicle drive system by using a single electric motor that can operate in two modes: driving the vehicle wheels through the drive system, and driving the power take-off through a separate connection interface. This merging eliminates the need for separate power supply, power electronics, and thermal management systems for the power take-off, while still enabling independent operation when needed.
Solution Approach 2:
The electric motor is designed with multi-functionality to serve both as the vehicle propulsion motor and as the power take-off drive motor. The drive system includes a connection interface that allows the power take-off to be independently driven from the same motor, making the motor universal for both functions and avoiding the need for dedicated separate systems.
2Device complexity
If the power take-off is driven by the prime mover, then the structure is simplified, but the power take-off cannot be driven independently of the rotational speed
Solution Approach 1:
The patent implements a dynamic shifting mechanism with a double shift element that can change the operational state of the power take-off independently. The shifting system allows the power take-off to be engaged or disengaged from the drive system at any rotational speed, enabling independent speed control while maintaining the simplified structure of using a single motor for both vehicle propulsion and power take-off drive.
3Adaptability or versatility
If additional shift elements are used to decouple the vehicle drive system from the vehicle wheels, then the power take-off can be independently operated, but the device complexity increases
Solution Approach 1:
The double shift element is designed to perform multiple functions simultaneously: it controls both the connection between the drive system and the vehicle wheels, and the connection to the power take-off. This multi-functional shift element reduces the total number of separate shift elements needed, as one element handles both decoupling operations, thereby reducing complexity while maintaining independent operation capability.
Data Source
AI summary
An electric drive axle for a vehicle includes at least one first electric vehicle drive system (1) for driving at least one vehicle wheel (11, 12) and at least one connection interface (8) for at least one power take-off (PTO). The vehicle drive system (1, 13) is coupled at least to one first double shift element (6) such that, at least in a first engagement position of the first double shift element (6), the vehicle drive system (1, 13) is drivingly coupled to at least one vehicle wheel (11, 12) and, in a second engagement position of the first double shift element (6), the vehicle drive system (1, 13) is decoupled from the at least one vehicle wheel (11, 12) and is drivingly coupled to the connection interface (8) for the power take-off (PTO). A vehicle with an electric drive axle is also provided.