Car rearview mirrors, known as the driver's "third eye," are essential for safe driving and integrate multiple functions such as angle adjustment, folding, and heating. However, the assembly process is complex, especially the bolt assembly stage, which involves multiple component stations including upper and lower covers, folding motors, and steering gears. To enhance bolt assembly efficiency and product consistency, automotive parts manufacturers commonly use automatic screw feeding and tightening systems.
.png)
However, rearview mirror screws, due to their long size and high length-to-diameter ratio, as well as the presence of a long smooth shank, pose challenges for the feeding process. Conventional circular vibratory feeder methods are prone to screw jamming and increased risk of jamming when blowing screws to the gun head. Additionally, because the thread diameter is larger than the shank diameter, screws can easily tilt during the gun head support phase.
Optimized Feeding Solutions
1. Feeding Method Optimization for Long Screws
For the automated conveyance of long screws, a step screw feeder is used. This feeder reduces wear on long screws and has a low screw jamming rate, ensuring continuous and stable screw feeding.
2.Noozle Structure Optimization
Given the high length-to-diameter ratio and long smooth shank of the screws, a swivel mouthpiece nozzle is employed. By driving the nozzle mechanism to switch between screw feeding and tightening channels, it ensures that screws are smoothly blown to the holding block. Compared to traditional methods of reducing the inlet channel angle and extending the nozzle length, the swivel mouthpiece nozzle structure is more compact and does not affect the workstation space layout. It can also accommodate screws of the same specification but different lengths with a small length-to-diameter ratio.
3. Effective Support During Feeding
A gripper cylinder is installed on the gun head mounting seat. During the blowing process, the holding block actively opens and then closes after the screw thread section passes through, effectively supporting the smooth shank part of the screw to prevent tilting.
Tightening Solutions
Due to the poor consistency of rearview mirror screws or workpieces, or due to frictional idling during hole recognition, torque may be within specifications, but the tightening angle may not be within the target range, leading to false alarms and affecting production line cycle time.
The tightening solution uses current-based tightening tools to monitor the angle after the screw reaches the contact surface. By setting the upper and lower limits of the angle based on the characteristics of soft and hard connections and on-site processes, it can accurately determine tightening abnormalities and ensure the quality control of bolt tightening. Additionally, it supports data upload functionality to ensure the traceability of the entire tightening process.
.gif)