Miniature Drive Locking Mechanism for Automobile Locks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing miniature drives for automobile locks face issues with gear reversal, where the worm gear wheel resets after power is switched off, leading to undesirable stress and the need for expensive freewheeling diodes to prevent reverse rotation.
Innovation Solution
A mechanical locking mechanism, such as a clamping wheel with spring arms or a wrap spring, is used to allow slight reverse rotation and prevent further turning, eliminating the need for freewheeling diodes and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a freewheeling diode is attached to the motor to prevent reverse rotation, then the motor is protected from high voltage and stress, but the manufacturing cost increases due to soldering work and additional materials
Solution Approach 1:
The patent replaces the electrical protection method (freewheeling diode) with a mechanical protection method (locking part with locking surface). The locking part mechanically prevents reverse rotation of the worm gear wheel through a locking surface that engages with a blocking surface, eliminating the need for freewheeling diodes and their associated soldering work, thus reducing manufacturing costs while maintaining motor protection.
2Reliability
If the gear is designed to prevent reverse rotation completely, then the motor is protected from stress, but the transmission cannot relax and may not return to the correct operating position
Solution Approach 1:
The patent creates a dynamic locking system where the locking part can adapt its state based on operational conditions. During normal operation, the locking surface prevents reverse rotation. However, when the cam follower loses contact with the cam profile (indicating transmission relaxation is needed), the locking mechanism allows the worm gear wheel to rotate back slightly to restore proper engagement, then re-engages to prevent further reverse rotation. This dynamic behavior protects the motor while allowing necessary transmission relaxation.
Solution Approach 2:
The patent incorporates a cam mechanism that anticipates and prepares for transmission relaxation needs. The cam profile is designed to maintain cam follower contact during normal operation, which keeps the locking mechanism engaged. When relaxation is needed, the cam follower naturally loses contact, triggering the locking mechanism to allow controlled reverse rotation to restore the correct operating position before re-engagement. This preliminary design of the cam profile ensures proper timing of the locking and unlocking actions.
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 mechanical solution effectively prevents gear reversal, allowing the transmission to relax into the correct operating position, reducing negative loads on the motor and eliminating the need for freewheeling diodes, thus enhancing the reliability and cost-effectiveness of the miniature drive.
Implementation Method 1
spring arms guided in a ring part, which are designed to allow a drive wheel assigned to the transmission to rotate with low friction in the drive direction
Implementation Method 2
rub with their braking surface on the inside of the ring part, so that they then automatically jam when the direction of rotation changes and brake the clamping wheel accordingly
Implementation Method 3
a wrap spring encompassing the drive wheel and is designed to allow a predetermined relaxation of the transmission
Implementation Method 4
a hook part end that protrudes beyond the drive wheel, which in the drive direction causing low friction on the drive wheel is moved against a locking block and, when turning back with the hook mouth, encompasses another locking block
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to miniature drives (1) for use in automobile locks. A return of the mechanism (3) once the lock is opened and the motor is shut down is prevented completely mechanically. For this purpose, the worm wheel is associated with a mechanically active locking element (8) which allows first to slightly turn back the wheel to unlock and reduce the load on the mechanism (3), but then prevents any further rotation against the direction of drive (7).