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    The Application of Wood Pulp Fiber in Clutch Facings Production

    In the intricate landscape of clutch facings production, Wood Pulp Fiber has emerged as a material of interest within the clutch facings friction materials. When integrated into clutch facings mixture and clutch facings mixes, it imparts unique properties to the final clutch facings, bringing both advantages and disadvantages to the table.

    I. Function in Clutch Facings Production

    Wood Pulp Fiber is typically added to the clutch facings mixture at a weight percentage ranging from 5% – 20%. Its role in the clutch facings production is multi – faceted. Firstly, it acts as a binder and reinforcement agent. The long, flexible fibers of the wood pulp can form an interwoven network within the clutch facings mix, enhancing the overall mechanical integrity of the clutch facings. Secondly, it can also contribute to the friction – regulating properties of the clutch facings, which is crucial for smooth clutch operation.

    II. Advantages

    A. Good Friction Performance

    1. Friction Coefficient Stability
      • Clutch facings with 10% Wood Pulp Fiber content exhibit a relatively stable friction coefficient. In a series of friction – coefficient tests under varying speeds (from 300 – 3000 RPM) and loads (from 20 – 250 N), the friction coefficient of these clutch facings remained within the range of 0.25 – 0.28, with a deviation of less than ±3%. This stability ensures smooth clutch engagement and disengagement, minimizing the risk of jerky movements during operation. For example, in a passenger vehicle clutch system, the use of Wood – Pulp – Fiber – containing clutch facings provides a seamless driving experience, especially during gear – shifting processes.
    1. Fade Resistance
      • Wood Pulp Fiber – enhanced clutch facings demonstrate decent fade resistance. When subjected to high – speed and high – load conditions for an extended period, the friction coefficient of these clutch facings only decreases by about 6% – 8%. In contrast, non – Wood – Pulp – Fiber – containing clutch facings can experience a friction – coefficient drop of 12% – 15%. This property is important for maintaining the clutch’s effectiveness during heavy – duty operations, such as in long – distance trucking or industrial machinery applications.

    B. Lightweight and Cost – effective

    1. Weight Reduction
      • Incorporating Wood Pulp Fiber into the clutch facings mixture can significantly reduce the weight of the clutch facings. For a standard – sized clutch facing, the addition of 15% Wood Pulp Fiber can lead to a weight reduction of approximately 10% – 15%. This weight reduction is beneficial in automotive applications, as it can contribute to improved fuel efficiency and overall vehicle performance.
    1. Low Cost
      • Wood Pulp Fiber is relatively inexpensive compared to many other materials used in clutch facings production. Using Wood Pulp Fiber in the clutch facings mixture can reduce the production cost by 15% – 25% compared to using some high – performance synthetic materials. This cost – effectiveness makes it an attractive option for manufacturers, especially in price – sensitive markets.

    C. Good Compressibility

    1. Smooth Operation
      • Wood Pulp Fiber has good compressibility, which allows the clutch facings to adapt well to the uneven surfaces of the clutch plates. In a compression – test, the clutch facings with Wood Pulp Fiber could be compressed by up to 10% – 15% without losing their structural integrity. This compressibility ensures a more uniform contact pressure between the clutch facings and the clutch plates, resulting in smooth clutch operation and reduced wear.

    III. Disadvantages

    A. Low Thermal Resistance

    1. Performance Degradation at High Temperatures
      • Wood Pulp Fiber has a relatively low thermal resistance. Clutch facings with Wood Pulp Fiber start to experience performance degradation at temperatures as low as 200 – 250°C. In a high – temperature test, when the temperature reached 250°C, the friction coefficient of the Wood – Pulp – Fiber – containing clutch facings decreased by about 15% – 20%, and the mechanical strength also dropped significantly. This limits their use in high – performance applications where the clutch facings are exposed to high temperatures, such as in racing cars or high – speed industrial machinery.
    1. Risk of Thermal Decomposition
      • At higher temperatures, typically above 300°C, there is a risk of thermal decomposition of the Wood Pulp Fiber. This decomposition can release harmful gases and reduce the lifespan of the clutch facings. In an experiment where the clutch facings were exposed to 350°C for 1 hour, the Wood Pulp Fiber in the clutch facings showed signs of significant decomposition, leading to a loss of mechanical and friction – related properties.

    B. Hygroscopicity

    1. Moisture Absorption and Performance Impact
      • Wood Pulp Fiber is hygroscopic, meaning it can absorb moisture from the environment. In a humidity – absorption test at 80% relative humidity for 48 hours, the Wood – Pulp – Fiber – containing clutch facings absorbed moisture equivalent to 8% – 12% of their dry weight. Moisture absorption can lead to a decrease in the mechanical strength of the clutch facings by about 10% – 15% and also affect the friction coefficient stability. This can be a problem in applications where the clutch facings are exposed to humid environments, such as in marine or outdoor – use machinery.

    C. Wear Susceptibility

    1. Faster Wear Rate
      • Compared to some more durable materials, clutch facings with Wood Pulp Fiber have a relatively higher wear rate. In a wear – test over 100,000 clutch engagement – disengagement cycles, the wear depth of clutch facings with Wood Pulp Fiber was 0.3 – 0.4 mm, while that of some high – performance clutch facings without Wood Pulp Fiber was only 0.1 – 0.2 mm. This faster wear rate may require more frequent replacement of the clutch facings, increasing maintenance costs.
    In conclusion, Wood Pulp Fiber offers certain advantages in the production of clutch facings, such as good friction performance, lightweight characteristics, and cost – effectiveness. However, its low thermal resistance, hygroscopicity, and wear susceptibility are significant drawbacks that need to be carefully considered. Further research and development efforts are required to address these challenges and fully utilize the potential of Wood Pulp Fiber in clutch facings friction materials.