# Matching Quality Detection System of Synchronizer Ring and Cone
## 3 Detection Program of Matching Quality between Synchronizer Ring and Cone
### Synchronous Friction Torque Detection Method for Synchronizer Ring and Cone  
After the acceptance criteria of the synchronizer is developed, it is necessary to design a reasonable detection method to ensure the synchronous friction in the shifting process. A common method is to use red lead powder to detect the fit of the synchronizer ring and the cone, and ensure that the fit degree is over 70%. However, if the red lead powder is unevenly applied, an error will occur. The detection requires manual identification, so the detection result is easily affected by subjective factors.  
In order to overcome these problems, this paper proposes a method based on friction torque detection and designs special tooling equipment. By applying a certain pressure to the synchronizer ring, and detecting the friction torque of the synchronizer ring and cone, their fitting degree is determined and the qualification standard for the parts is established. At the same time, the accurate measurement of the synchronizer ring backup gap is realized.  
The main measurement index of the system for detecting the matching quality of the synchronizer ring and cone is the dynamic friction torque value, generated by the end face force of the specific value, after the inner cone surface of the synchronizer ring is matched with the outer cone surface of the synchronizer cone. According to Equation (2), the friction torque can be calculated from the shift force based on the friction coefficient, the average radius of the friction surface, and the cone angle. At the same time, the backup gap of the synchronizing ring gap is measured to determine the degree of wear of the workpiece.  
The installation of the synchronizer on the detection platform is shown in Figure 7. The dynamic friction torque is measured by first bonding the synchronizing ring and the synchronizer cone together, then injecting the lubricating oil to lubricate, applying a fixed force on the upper side, then a motor is driven to rotate the workpiece below. At the same time, a high-precision torque sensor is used to continuously measure the dynamic friction torque. Finally, the average torque at this stage is calculated as the index.  
The measurement method of synchronizer ring backup axial gap is shown as follows in Figure 8.  
First, after placing the measurement reference block (H1) on the synchronizer cone, putting the synchronizer ring. Then move the probe down and the probe force is set to F at this time. After the measured value of H2 is displayed, move the probe up a certain distance to facilitate the removal of the synchronizer and the reference block. Next, move the probe down again to bring the force to F, at which point the measured value (H3) is obtained. The synchronizer ring backup gap \(\rm{H}=\rm{H1}-\rm{H2}-\rm{H3}\) can be calculated.  
In actual detection, the torque value of the device needs to be calibrated. A certain number of synchronizing rings and cone matching components confirmed as qualified products are manually selected. Then, under lubrication conditions, the workpiece is calibrated to determine the dynamic friction torque value. After the mathematical statistics, the dynamic friction torque qualified range of the synchronous ring and cone phase matching component is determined. If one of the two indicators (dynamic friction torque and backup gap) fails, then the equipment will issue a warning.  
Figure 7: Installation schematic diagram of the synchronizer on the detection platform.