Parking Cam Unlocking Mechanism for Power-Off Electronic Parking
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Solution Overview
Problem
Existing electronic parking mechanisms in new energy vehicles have insufficient structural flexibility, short service life, and require drivers to exit the vehicle for mechanical unlocking when the parking motor is powered off, leading to safety and comfort issues.
Innovation Solution
A mechanical unlocking mechanism for a gearbox that includes a parking cam assembly connected via a pull rod assembly to the vehicle's control part, allowing drivers to unlock the vehicle from inside without power, and a torsion spring failure prevention assembly to ensure unlocking functionality even in case of torsion spring failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the parking motor is powered off, then the mechanical unlocking mechanism can be activated, but the driver must operate under the vehicle which reduces safety and comfort
Solution Approach 1:
A cable assembly is introduced as an intermediary transmission mechanism between the driver's operation inside the cabin and the parking cam outside the vehicle. The cable transmits the unlocking force through the vehicle structure, allowing the driver to remain inside the cabin while still activating the mechanical unlocking function.
2Ease of operation
If a torsion spring is used for the mechanical unlocking mechanism, then the unlocking function is achieved, but the mechanism becomes vulnerable to spring failure
Solution Approach 1:
A spring failure prevention assembly is installed beforehand to protect against the harmful effect of spring failure. The assembly includes a limiting structure that prevents the pawl from falling into the parking gear groove when the torsion spring fails, and a second spring that provides alternative elastic force to maintain unlocking functionality.
Solution Approach 2:
When the torsion spring fails, the system automatically switches to using the second spring as the active elastic element. The failure prevention assembly redirects the mechanical force through the second spring, allowing the system to recover its unlocking function without requiring part replacement or external intervention.
3Device complexity
If the pawl is allowed to fall into the parking gear groove in non-parking state, then the structure is simple, but the vehicle safety is compromised
Solution Approach 1:
The failure prevention assembly includes a limiting structure that preemptively prevents the pawl from falling into the parking gear groove during non-parking operations. This preliminary protective measure blocks the harmful effect before it can occur, maintaining safety without requiring complex control systems.
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
Enables safe and comfortable mechanical unlocking from within the vehicle without power, preventing pawl engagement with the parking gear and ensuring operation even with torsion spring failure, thus enhancing safety and comfort.
Implementation Method 1
a torsion spring (4) one end of which is sleeved on the pawl shaft and the other end of which is fixed on the gearbox case
Implementation Method 2
a parking cam assembly comprising a parking guide shaft and a parking cam, the parking cam is sleeved on the parking guide shaft
Implementation Method 3
The parking cam is connected with the control part in the cab via the pull rod assembly
Data Source
Figure 1
Figure 2~3
AI summary
A mechanical unlocking mechanism for electronic parking is provided, which comprises a parking cam assembly, a pawl assembly, a pull rod assembly and a parking gear (1); the parking cam assembly comprises a parking guide shaft (10) and a parking cam (13), the parking cam (13) is sleeved on the parking guide shaft (10), at least a first convex part and a second convex part are provided at two sides of the parking cam (13), and a connecting part is provided on the second convex part; the pull rod assembly is connected with the parking cam (13) via the connecting part, and the pull rod assembly pulls the second convex part to drive the parking cam (13) to rotate; the parking gear (1) can be fixed or rotatable according to the pawl assembly being in a first position where the parking gear (1) parks in or a second position where the parking gear (1) parks out as the parking cam (13) rotates. The mechanical unlocking mechanism according to the present disclosure provides an emergent mechanical unlocking function when the parking motor is powered off, and the driver can perform manual mechanical unlocking in the cab without getting off the vehicle, so it has high safety and good operation comfort.