Resilient Park Lock Coupling for Shock Load Reduction
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Solution Overview
Problem
Electric vehicles lack a clutch to disconnect the electric motor from the wheels, leading to sudden and intense deceleration of the rotor when the park lock is engaged, causing high loads on the park lock system and potential damage due to shock loads exceeding friction loads.
Innovation Solution
A park lock system incorporating a resilient member to reduce deceleration forces by rotationally connecting the rotor shaft to the park lock wheel, allowing for elastic deformation and dissipation of rotational energy, thereby reducing dynamic loads on the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a park lock mechanism is engaged to prevent vehicle rolling, then the vehicle stability is improved, but high loads and shock deceleration occur on the park lock system and drive unit components
Solution Approach 1:
A resilient member is introduced between the rotor shaft and the park lock mechanism to cushion the shock load beforehand. The resilient member elastically deforms during rotor deceleration, absorbing impact energy and reducing peak loads on the park lock mechanism and drive unit components before they can cause damage.
Solution Approach 2:
The mechanical connection between the rotor shaft and park lock mechanism is changed from rigid to resilient by introducing a compliant element. This parameter change allows the system to dynamically adapt to deceleration forces, transforming the rigid load path into a compliant one that can absorb energy and reduce peak stresses.
2Productivity
If the park lock is engaged during vehicle movement, then the vehicle can be stopped, but sudden and intense rotor deceleration causes high shock loads on the park lock system
Solution Approach 1:
The resilient member is positioned in the load path between the rotor shaft and park lock mechanism to provide beforehand cushioning. When the park lock is engaged during movement, the resilient member elastically deforms to cushion the sudden rotor deceleration, reducing shock loads on the park lock system while still enabling effective vehicle stopping.
Solution Approach 2:
The resilient member acts as an intermediary element between the rotor shaft and the park lock mechanism. It mediates the interaction between the rotating rotor and the locking mechanism, filtering out harmful shock loads while transmitting the necessary torque to enable the park lock function.
3Reliability
If larger components are used in the park lock system to withstand high loads, then the system reliability is improved, but the system size and weight increase
Solution Approach 1:
By introducing the resilient member to cushion shock loads beforehand, the peak loads on the park lock system components are reduced. This allows the use of smaller, lighter components that are adequately sized for the reduced load conditions while still maintaining the required reliability and durability for the application.
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
The resilient member mitigates deceleration and dynamic loads on the park lock system, enabling the use of smaller components and reducing the risk of damage from sudden deceleration, while allowing for a more compact design.
Implementation Method 1
The resilient member is arranged for decreasing deceleration forces when engaging the park lock... allowing for elastic deformation and dissipation of rotational energy
Implementation Method 2
a resilient member rotationally connecting the first rotational member and the second rotational member
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A park lock system is used in vehicles to provide a coupling between a rotor of an electric motor powering the vehicle to part of the chassis of the vehicle to, in an engaged setting, prevent rolling of the vehicle when the vehicle is parked on a hill. The park lock system may however also be engaged while the vehicle is rolling. In such a case, high loads may occur on parts of the vehicle's powertrain due to sudden deceleration of those parts. To reduce the deceleration after engaging the park lock mechanism, a resilient member is introduced. The resilient member is arranged to resiliently deform and slow the sudden deceleration, decreasing loads on parts of the powertrain due to the deceleration. By virtue of these decreased loads, smaller and/or lighter components may be used in the powertrain which may be advantageous for the size and/or weight of the vehicle.