Vehicle Flap Spindle Support with Centrifugal Brake Locking
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Solution Overview
Problem
Existing support devices for vehicle flaps, such as suspension struts or gas springs, fail to adequately prevent undesired closing movements, especially when the drive unit fails, posing a risk of injury due to collision or pinching.
Innovation Solution
A support device with a spindle drive and a brake device activated by centrifugal forces, which includes a first and second centrifugal body that engage with the housing to brake the rotation of the spindle rod and nut, ensuring secure support of the vehicle flap in all positions, even when the drive unit fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If simple suspension struts or gas springs are used as support devices, then the device complexity is low, but the reliability is insufficient to prevent undesired closing movements when the drive unit fails
Solution Approach 1:
The patent combines a spindle drive mechanism with a brake device into an integrated support device. The spindle drive includes a spindle rod, spindle nut, and brake device that work together as a unified system. This merging of functions (support + braking) into a single device provides both structural simplicity and enhanced reliability compared to separate suspension strut and brake system configurations.
Solution Approach 2:
The brake device acts as an intermediary component between the spindle drive and the housing. It includes a brake element that can be pressed against the spindle rod or spindle nut to generate braking torque, mediating the force transmission and providing controlled resistance to undesired movements while maintaining the overall system's functional integrity.
2Reliability
If a brake device is added to the spindle drive to prevent undesired closing movements, then the reliability improves, but the device complexity increases
Solution Approach 1:
The brake device is designed with dynamic characteristics through the use of a wrap spring that can be tensioned and released. The brake element can be dynamically engaged or disengaged from the spindle rod/nut based on operational conditions. This dynamic design allows the brake function to be activated only when needed, reducing the perceived complexity while maintaining high reliability for preventing undesired closing movements.
Solution Approach 2:
The brake device utilizes parameter changes in the form of variable braking torque through the wrap spring mechanism. The spring can be tensioned to different degrees, changing the braking force parameter. This allows the brake device to adapt its braking capability to different operational states, providing reliable prevention of undesired movements while maintaining a relatively simple structural design through parameter adjustment rather than complex mechanical linkages.
3Reliability
If the brake element is constantly pressed against the spindle rod or spindle nut, then the braking reliability is high, but the energy loss increases due to continuous friction
Solution Approach 1:
The brake device operates on a periodic or on-demand basis rather than continuously. The wrap spring mechanism allows the brake element to be engaged when braking is needed (preventing undesired closing movements) and disengaged during normal operation. This periodic action maintains high braking reliability when required while minimizing energy loss from continuous friction by allowing the brake element to separate from the spindle rod or nut during non-braking periods.
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 support device reliably prevents undesired closing movements by activating the brake device when centrifugal forces exceed a threshold, ensuring safe operation and preventing injuries.
Implementation Method 1
the brake device comprises a brake element that is in force-fitting contact with one of the spindle and spindle nut
Implementation Method 2
the pretensioning means is formed as a wrap spring, which pretensions the brake element radially against one of the external spindle thread and internal spindle nut thread
Implementation Method 3
the first brake device can be activated by rotating it relative to the housing about a central axis of rotation via centrifugal forces
Data Source
AI summary
The present disclosure relates to a support device, in particular for a vehicle flap, comprising a housing (2) which can be connected between the vehicle flap and the vehicle body and which comprises at least one first housing part (3) and a second housing part (4) said the first housing part (3) and second housing part (4) are movable relative to each other in a telescopically guided manner. The support device also includes a spindle drive (8) which is coupled to the housing (2). The spindle drive (8) comprises a spindle rod (9) and a spindle nut (10) which is in thread engagement with the spindle rod (9), and one of the aforementioned components, i.e. the spindle rod (9) and the spindle nut (10), is rotatably arranged in the housing (2) about a spindle axis (S) and the respective other component is rotationally fixed in the housing (2). The support device also includes a first brake device (16) which is coupled to one of the aforementioned components in order to brake the rotation of the said component. The first brake device (16) can be activated by being rotated relative to the housing (2) about a central rotational axis via centrifugal forces.