The Application of Cellulose Fiber in Clutch Facings Production
Cellulose Fiber has emerged as a significant material in the production of clutch facings, playing a crucial role in clutch facings friction materials, clutch facings mixtures, and clutch facings mixes. This article delves into its application, highlighting both the advantages and disadvantages, along with key technical parameters.
Technical Parameters
- Fiber Dimensions
- Cellulose fibers used in clutch facings usually have a diameter in the range of 10 – 30 micrometers. This fine diameter enables better dispersion within the clutch facings mixture. For instance, a diameter of around 15 micrometers allows for a more homogeneous distribution, enhancing the overall performance of the clutch facings.
- The aspect ratio (length – to – diameter ratio) of these fibers typically ranges from 20 – 50. A higher aspect ratio, like 40, contributes to improved mechanical interlocking within the matrix, enhancing the strength of the clutch facings.
- Mechanical Properties
- The tensile strength of cellulose fiber is approximately 100 – 200 MPa. When incorporated into clutch facings mixes at a 10% volume fraction, it can increase the overall tensile strength of the clutch facings by 10 – 15%.
- The elastic modulus of cellulose fiber is in the range of 10 – 20 GPa. This property helps in providing the necessary stiffness to the clutch facings, ensuring stable operation during engagement and disengagement.
Advantages
- Reinforcement and Durability
- In a clutch facings mixture with 12% cellulose fiber by weight, the wear resistance can be improved by 20 – 25%. This is due to the fiber’s ability to reinforce the matrix, reducing the rate of material removal during friction. For example, in a standard wear test of 100,000 clutch cycles, clutches with cellulose – fiber – containing facings showed 25% less material wear compared to those without.
- The fatigue life of clutch facings is extended by 30 – 40% when cellulose fiber is added. This is because the fiber can withstand cyclic loading and prevent crack propagation, thus increasing the overall durability of the clutch facings.
- Cost – effectiveness
- Cellulose fiber is relatively inexpensive compared to some high – performance synthetic fibers. In clutch facings production, using cellulose fiber can reduce the material cost by 15 – 20% without sacrificing too much on performance. This cost – saving aspect makes it an attractive option for manufacturers aiming to produce cost – effective clutch facings.
- Friction Stability
- It helps in maintaining a stable coefficient of friction. In a test where the clutch facings were subjected to different speeds and loads, the coefficient of friction of the facings with 15% cellulose fiber varied within a narrow range of ±0.05, ensuring smooth clutch operation.
Disadvantages
- Thermal Limitations
- As mentioned before, cellulose fiber starts to degrade at 200 – 250°C. In high – performance racing clutches, where temperatures can easily exceed 300°C during aggressive driving, the use of cellulose fiber may lead to premature failure. In a high – temperature test simulating racing conditions, the clutch facings with cellulose fiber lost 40 – 50% of their mechanical properties after 5 minutes at 350°C.
- Moisture – related Issues
- In a high – humidity environment (90% relative humidity), clutch facings with 15% cellulose fiber can absorb up to 10% of their weight in moisture within 24 hours. This moisture absorption can cause swelling, leading to a 10 – 15% change in the dimensions of the clutch facings.
- The absorbed moisture also weakens the fiber – matrix interface. In a shear test after moisture absorption, the shear strength of the clutch facings decreased by 15 – 20%, affecting the overall performance of the clutch.
- Processing Challenges
- Cellulose fiber has a tendency to agglomerate during the mixing process in clutch facings production. This agglomeration can result in non – uniform distribution within the clutch facings mixture. In a study, when the mixing process was not optimized, up to 20% of the cellulose fiber formed agglomerates, leading to inconsistent performance of the clutch facings.
In summary, while Cellulose Fiber offers several advantages in clutch facings production, such as reinforcement, cost – effectiveness, and friction stability, its thermal, moisture – related, and processing limitations need to be carefully considered. Further research and development are required to overcome these challenges and fully utilize the potential of cellulose fiber in the production of high – quality clutch facings friction materials.