Transmission Shaft Self-Locking via Tilting Contact Point
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Solution Overview
Problem
Existing transmission drive devices for motor vehicle comfort systems, such as window lifters and sunroof drives, face inefficiencies due to self-locking issues when axial forces are low, requiring powerful electric drives and resulting in a heavier and less compact design. The goal is to minimize self-locking at low axial forces while maximizing it at higher forces to enable a lightweight and compact transmission drive.
Innovation Solution
The stop element and damping element are designed to increase their distance from the shaft's longitudinal axis with rising axial force, generating a disproportionate counterforce through friction, which enhances self-locking when needed, by allowing the stop element to tilt and the damping element to absorb forces effectively, thus optimizing the transmission drive's efficiency and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a powerful electric drive is used to overcome initial resistance in the gearbox, then the gear drive device can operate reliably, but the drive unit becomes heavier and more complex
Solution Approach 1:
The system uses the axial force from the element to be adjusted itself to generate the counterforce for self-locking, rather than requiring an additional powerful drive mechanism. The starting element and damping element work together to convert the axial force into a counterforce that automatically prevents unwanted rotation.
Solution Approach 2:
The invention changes the parameter of contact point distance from the shaft axis. As axial force increases, the contact point distance increases, which disproportionately increases the counterforce. This dynamic parameter change allows the system to adapt its self-locking capability based on the applied load.
2Stability of the object's composition
If high self-locking is maintained at all times to prevent unwanted adjustment, then position stability is improved, but the drive motor requires higher power consumption
Solution Approach 1:
The system transitions from a static self-locking mechanism to a dynamic one where the self-locking force changes with the applied axial force. The starting element can tilt relative to the shaft axis, and the contact point distance varies dynamically based on the magnitude of the axial force, allowing the system to maintain stability only when needed.
Solution Approach 2:
The invention changes the parameter of contact point distance from the shaft axis. As axial force increases, the contact point distance increases, which disproportionately increases the counterforce. This dynamic parameter change allows the system to adapt its self-locking capability based on the applied load.
3Volume of moving object
If a compact and lightweight gear drive device is designed, then the overall system size is reduced, but generating sufficient counterforce for self-locking becomes more difficult
Solution Approach 1:
The invention changes the parameter of contact point distance from the shaft axis. As axial force increases, the contact point distance increases, which disproportionately increases the counterforce through the damping element. This allows a compact design to generate sufficient counterforce when needed.
Solution Approach 2:
The starting element is designed to tilt relative to the shaft axis, introducing an angular dimension to the force transmission. This tilting mechanism converts axial force into a counterforce through the damping element, effectively using a different dimensional approach to generate the required locking force.
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
This design allows for a disproportionately increasing self-locking mechanism with axial force, enabling the use of a lighter drive motor and achieving a more efficient, compact transmission drive device by minimizing self-locking at low forces and maximizing it at higher forces, resulting in a more efficient and compact transmission drive.
Implementation Method 1
a damping element (32, 32a, 32b, 32c, 32d) arranged on the side of the starting element (30) facing away from the shaft end (15)
Implementation Method 2
the frictional force that develops between the shaft or the contact point of the shaft end results from the sum of the force acting in the longitudinal direction of the shaft and the frictional torque
Data Source
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AI summary
The invention relates to a transmission drive device (10) comprising a shaft (14; 14a) which is arranged in a housing (12) in a longitudinally movable manner in the direction of the shaft axis (26) and comprising a shaft end (15; 15a) which is formed on an end face and which is supported at least indirectly on the housing (12) via at least one starting element (30). Either the shaft end (15) or the starting element (30) has a rounded design at least in some regions, a bearing point (31) being formed between the starting element (30) and the shaft end (15; 15a), and the starting element (30) being coupled to a damping element (32; 32a to 32d) which allows a movement of the starting element (30) in the event of an axial application of force (FA, FA1, FA2) by means of the shaft (14; 14a). According to the invention, the starting element (30) and/or the damping element (32; 32a to 32d) is/are designed and/or arranged such that the distance (r) of the bearing point (31) to the longitudinal axis (26) of the shaft (14; 14a) increases as the axial application of force (FA, FA1, FA2) increases at least starting from a specified level of the application of force (FA, FA1, FA2).