EV Gearbox Parking Lock Using Dual Form-Fit Clutches
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Solution Overview
Problem
Existing electric vehicle gearboxes require additional parts for parking brake functionality, increasing the bill of materials and complexity, whereas the proposed solution integrates the form-fit clutches to provide both transmission ratios and a parking state, eliminating the need for a separate parking brake mechanism.
Innovation Solution
The gearbox employs two form-fit clutches to offer two switchable transmission ratios and a parking state where both clutches engage, blocking rotational movement, thus eliminating the need for a separate parking brake by utilizing existing clutches for this function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate parking brake mechanism is added to the gearbox, then the parking brake function is improved, but the device complexity and bill of materials increase
Solution Approach 1:
The patent merges the parking brake function with the existing form-fit clutches in the gearbox. The first and second form-fit clutches are configured to engage simultaneously to provide a parking state, eliminating the need for a separate parking brake mechanism. This combining approach maintains reliable parking functionality while reducing the overall number of parts and simplifying the device structure.
Solution Approach 2:
The form-fit clutches in the gearbox are designed to serve multiple functions: they provide transmission ratio switching during normal operation and simultaneously serve as the parking brake mechanism when both clutches are engaged. This multi-functionality allows the same components to fulfill both transmission and parking locking roles, reducing the bill of materials while maintaining functional reliability.
2Reliability
If additional parking brake parts are included, then the parking brake function is improved, but the manufacturing cost increases
Solution Approach 1:
The patent combines the parking brake function with existing gearbox components (form-fit clutches), eliminating the need to manufacture and supply additional dedicated parking brake parts. This merging strategy reduces the bill of materials and associated manufacturing costs while maintaining the required parking brake functionality.
Solution Approach 2:
The form-fit clutches are designed to perform dual roles: transmission switching and parking brake function. By making these components universal, the patent avoids the need for separate dedicated parking brake parts, thereby reducing manufacturing complexity and material costs while ensuring reliable parking capability.
Data Source
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AI summary
A gearbox (1, 1a..1d) for an electric drivetrain (28, 28a..28e) is proposed, which comprises a gearbox input (2), a gearbox output (4), a number of gear wheels (5..8) and at least a first and a second form-fit clutch (9, 10) providing at least two switchable transmission ratios between the gearbox input (2) and the gearbox output (4) in different switching states (D1, D2) of the form-fit clutches (9, 10). In addition, a parking state (P) is provided, in which both the first transmission ratio and the second transmission ratio are engaged/activated between the gearbox input (2) and the gearbox output (4) at the same time and a transmission of a rotational movement between the gearbox input (2) and the gearbox output (4) is blocked. Moreover, an electric drivetrain (28, 28a..28e) with such a gearbox (1, 1a..1d) and a vehicle (34) with such an electric drivetrain (28, 28a..28e) are disclosed.