Motor Vehicle Rear Lock Delayed Opening Mechanism
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Solution Overview
Problem
Existing motor vehicle rear locks generate acoustically audible and uncomfortable opening noises due to abrupt pressure dissipation when the pawl disengages from the rotary latch, leading to a negative impact on user experience.
Innovation Solution
A rear lock design featuring a rotary joint coupled to a variable-length lever that controls the pawl's movement from an engaged to an intermediate position, allowing for a controlled and delayed release, reducing the prestress on the tailgate by moving tangentially and then radially relative to the rotary latch, thus minimizing noise and discomfort during opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pawl disengages from the rotary latch to open the tailgate, then the tailgate can be opened, but the built-up pressure dissipates abruptly causing acoustically audible opening noise and discomfort
Solution Approach 1:
The patent applies preliminary action by moving the pawl radially outward along its movement path before disengagement occurs. This preliminary radial movement reduces the prestress between the tailgate and closing element in advance, so that when the pawl finally disengages from the rotary latch, the pressure dissipates gradually rather than abruptly, eliminating the acoustically audible opening noise while maintaining smooth tailgate operation
2Object-generated harmful factors
If the pawl moves radially outward before disengagement, then the prestress is reduced and noise is minimized, but the structure becomes more complex
Solution Approach 1:
The patent employs dynamics by implementing a movement path for the pawl that combines both radial and tangential components. The radial component enables prestress reduction before disengagement, while the tangential component maintains engagement with the rotary latch during the process. This dynamic movement trajectory is achieved through the geometric arrangement of the pawl's rotational axis relative to the rotary latch, eliminating the need for additional complex mechanical 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 solution effectively reduces the opening noise and enhances the comfort of the opening process by gradually relieving the prestress on the tailgate before the pawl and rotary latch are disengaged, ensuring a smooth and quiet operation.
Implementation Method 1
the rotary joint (12) is coupled to a lever (38) of variable length which controls the movement of the pawl (9) from the engaged position into an intermediate position driving and braking from the intermediate position into the release position
Implementation Method 2
In the closed position of the tailgate, it is prestressed against a seal, for example. Prestressing is to be understood here as meaning that the sealing counter-pressure caused by a flap seal counteracts the closing of the motor vehicle flap
Data Source
Figure 1
Figure 2~3
Figure 4~8
AI summary
The tailgate lock has a closing element (2) which is set in the closed position. A rotary latch (5) and a pawl (9) movable between the release position and engaged position in the direction of the closing element, are biased during the open position of the closing element. The pawl is set in the release position, when the rotary latch is out of engagement. When the latch is in engaged position, the latch is prevented from moving in the direction of open position. A delay unit is coupled to the latch, according to movement speed of latch, for the release of closing element.