Parking Lock Wheel Axial Offset Torsional Stiffness
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Solution Overview
Problem
Existing parking block units for electric drive arrangements face challenges in reducing the load on machine elements when the parking lock is engaged, as they fail to effectively absorb kinetic energy and often require significant installation space.
Innovation Solution
A parking block unit design featuring a parking bike with a stem section and a connecting section, where the locking element can be axially offset, converting kinetic energy into radial and tangential forces that increase torsion length and reduce torsional stiffness, allowing for elastic deformation and reduced load on machine elements, while maintaining a compact installation space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the parking lock wheel has a straight wheel body with locking and connecting sections aligned axially, then the structure is simple and compact, but the torsional stiffness is high causing excessive stress on machine elements during engagement
Solution Approach 1:
The parking lock wheel employs a curved web section connecting the locking section and connecting section, replacing the straight alignment. This curvature creates a lever arm effect that increases torsional flexibility, allowing the wheel to deflect elastically during engagement and reduce stress transmission to machine elements while maintaining structural integrity
Solution Approach 2:
The invention introduces an axial offset between the locking section and connecting section centers, creating a three-dimensional configuration. This axial separation combined with the curved web section provides additional torsional compliance in the axial dimension, enabling energy absorption through elastic deformation without increasing radial or lateral dimensions
2Loss of energy
If the parking lock wheel uses a curved web section with axial offset between locking and connecting sections, then the torsional stiffness is reduced to absorb kinetic energy, but the installation space increases
Solution Approach 1:
The web section's curvature radius and axial offset distance are optimized as geometric parameters to achieve the desired torsional flexibility. By carefully selecting these parameters, the design achieves sufficient energy absorption capability while constraining the overall volume within acceptable limits for vehicle integration
Solution Approach 2:
The web section functions as a flexible structural element that elastically deforms during parking lock engagement. This thin, curved connection allows kinetic energy to be absorbed through elastic strain in the web section itself, converting harmful impact energy into recoverable elastic potential energy without requiring bulky damping components
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 proposed design effectively reduces the load on machine elements by converting kinetic energy into elastic deformation energy, enhancing the parking block's ability to absorb energy and preventing unintended vehicle movement, while minimizing the installation space required.
Implementation Method 1
allows the locking section of the parking lock wheel to deflect radially, thus elastically storing deformation energy within the parking wheel
Implementation Method 2
The axial offset of the locking section relative to the connecting section of the proposed parking lock unit offers the advantage of increasing the torsional length of the power path between the parking lock and the tires, and between the parking lock and the drive unit, thereby reducing the torsional stiffness of the power path
Data Source
Figure 1a~1b
Figure 2~3
Figure 4
AI summary
A parking lock unit for a drive arrangement, in particular with an electric motor, comprising: a parking lock casing, a parking lock wheel, which parking lock wheel is connected for conjoint rotation to a part of the drive arrangement which is mounted rotatably about an axis of rotation by means of at least one bearing, and which parking lock wheel has a connecting portion and a detent portion which are connected to one another by means of a web portion; a locking element which is mounted in the parking lock casing and which can lock and permit a rotational movement of the parking lock wheel about a longitudinal axis of the parking lock wheel, and a controllable locking actuator, which can transfer the locking element reversibly into a position in which it locks the parking lock wheel and a position in which it releases the parking lock wheel, wherein the parking lock wheel is designed such that the detent portion is axially offset relative to the connecting portion.