Optical Pickup Transfer Mechanism with Multi-Thread Screw
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional feed-screw type transfer mechanisms for optical pick-up devices in optical disc drives face issues such as high production costs due to precise requirements, the 'running over of teeth' phenomenon during impact loads, and non-uniform lubricant application leading to scattering, which complicates the structure and increases costs.
Innovation Solution
A feed-screw type transfer mechanism with a multiple-thread screw on the drive shaft and a follower member featuring two main teeth and a subsidiary tooth, where the subsidiary tooth is not involved in transfer, reduces the circumferential surface area and allows uniform lubricant distribution, thereby minimizing the 'running over of teeth' phenomenon and lubricant scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-thread screw is used as the feed screw, then the structure is simple, but the circumferential surface area between thread grooves is large causing teeth to run over during impact loads
Solution Approach 1:
The single-thread screw is segmented into multiple threads (double-thread or triple-thread screw) around the drive shaft circumference. This segmentation divides the circumferential surface into smaller sections between adjacent thread grooves, preventing teeth from running over during impact loads while maintaining structural simplicity.
2Reliability
If a multiple-thread screw is used to reduce circumferential surface area, then resistance to running over of teeth improves, but uniform lubricant application becomes difficult
Solution Approach 1:
A lubricant supply mechanism is provided that delivers lubricant to specific local positions between adjacent thread grooves of the multiple-thread screw. This ensures uniform lubricant application only where needed between the threads, rather than attempting to coat the entire screw surface, thereby solving the manufacturing difficulty while maintaining the reliability benefits of multiple threads.
3Speed
If high speed transfer is pursued with large feed pitch, then transfer speed increases, but the circumferential surface area between threads increases causing teeth to run over
Solution Approach 1:
By using a multiple-thread screw configuration, the circumferential surface is segmented into smaller intervals between adjacent thread grooves. This allows the use of larger feed pitches for high-speed transfer while preventing teeth from running over, as the multiple thread starts provide more frequent engagement points around the circumference.
4Manufacturing precision
If precise processing is performed on screw portion and teeth to achieve high accuracy transfer, then transfer accuracy improves, but manufacturing cost increases
Solution Approach 1:
The multiple-thread screw configuration provides inherent self-aligning and self-correcting properties that reduce the need for extremely precise processing. The multiple thread starts distribute loads and provide redundancy, allowing acceptable transfer accuracy to be achieved with less stringent manufacturing tolerances, thereby reducing costs.
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 occurrence of the 'running over of teeth' phenomenon and ensures uniform lubricant application, enhancing the transfer mechanism's reliability and accuracy while maintaining a simple structure and reducing costs.
Implementation Method 1
a feed-screw type transfer mechanism includes a drive shaft provided with an external screw around its external circumference and a follower member having teeth that are engaged with the external screw
Implementation Method 2
a lubricant such as grease is applied to the screw portion of the drive shaft
Data Source
AI summary
A feed-screw type optical pick-up device transfer mechanism is provided for transferring an optical pick-up device through a base member coupled to a follower member in a state in which teeth of the follower member are engaged with a screw portion threaded around an external circumference of a driveshaft. The teeth of the follower member include two main teeth relating to the transfer of the optical pick-up device, and at least one subsidiary tooth provided between the two main teeth and not related to the transfer of the optical pick-up device.