Abstract:
A carbon fiber washer is provided and includes a carbon fiber fabric made of a plurality of fiber bundles being woven, in which each of the plurality of fiber bundles is made of discontinuous fibers; the advantage of the carbon fiber washer of the present invention includes high temperature and fatigue resisting, and weather proofing. The structure of the carbon fiber washer is stable due to the use of discontinuous fibers; breakages of discontinuous fibers do not affect other unbroken discontinuous fibers, so that the structure of the carbon fiber washer would not be loosened or delaminated and the service life can be prolonged accordingly.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to carbon fiber washer, and more particularly to a carbon fiber washer having discontinuous carbon fibers. 
       BACKGROUND OF THE INVENTION 
       [0002]    Washers and gaskets are essential to mechanical structures. For instance, metal washers or flat washers are often utilized for fastening screws in order to prevent loosening, spring washers are often utilized to press against objects to prevent leakages, and transmission or winding gaskets are usually implemented in rotating mechanisms. Taking conventional winding gaskets used in fishing reels as an example, conventional winding gaskets bear with abrasions from physical frictions during high-speed rotations, and some are even applied to auxiliary braking mechanisms, and so abrasion resisting, self-lubricating, and high temperature resisting performances of the gaskets are highly required. Metal based and composite materials are the two major types of materials being used in fishing reels or other similar mechanisms. Metal-based materials have lots of benefits such as outstanding thermal conductivities, however, thermal expansion of metals causes problems; Composite materials like winding gaskets contains laminated fiber fabrics formed of continuous fibers, see  FIG. 8 , and that breakages of the continuous fibers would cause delamination thereby loosening the entire structure and reducing the service life. 
       SUMMARY OF THE INVENTION 
       [0003]    In light of the above imperfections, a carbon fiber washer is provided. The carbon fiber washer includes woven discontinuous fibers, so that while the carbon fiber washer is worn and a part of carbon fibers are abrade or torn, others will not be affected. As a result, the entire structure will not be loosened or delaminated, so as to prolong the service life of the carbon fiber washer. 
         [0004]    A carbon fiber washer is provided and includes a carbon fiber fabric made of a plurality of woven fiber bundles, and each of the fiber bundles is formed of a plurality of discontinuous fibers. 
         [0005]    According to an embodiment of the present invention, a bonding material is in between two or more of the carbon fiber fabrics, the bonding material partially infiltrates or impregnates the spaces between the discontinuous fibers of the carbon fiber fabrics; the outer surface of the carbon fiber washer includes at least a portion not infiltrated with the bonding material. 
         [0006]    According to an embodiment of the present invention, the carbonization ratio of the carbon fiber fabric ranges from 10% to 95%. 
         [0007]    According to an embodiment of the present invention, the impregnation ratio of the bonding material being infiltrated into the carbon fiber fabrics ranges from 40% to 80%. 
         [0008]    According to an embodiment of the present invention, the bonding material is thermal-plastic or thermal-setting resin, and the discontinuous fiber is formed by carbonizing acrylic fiber. 
         [0009]    According to an embodiment of the present invention, the thermal-plastic resin is polyester or polysulfone resin, and the thermal-setting resin is epoxy or phenolic resin. 
         [0010]    According to an embodiment of the present invention, a stacking structure can be formed by two of the carbon fiber fabrics with a supporting material, and the two carbon fibers are located at the outer side of the stacking structure. 
         [0011]    According to an embodiment of the present invention, the carbon fiber washer further includes a supporting material disposed between two of the bonding materials, each of the bonding materials is disposed between one of the carbon fiber fabrics and the supporting material, and the outmost layers of the carbon fiber washer are the two of the carbon fiber fabrics. 
         [0012]    According to an embodiment of the present invention, the supporting material is carbon fiber fabric, thin fiber fabric, basalt fiber fabric, or glass fiber fabric or the combination thereof. 
         [0013]    Accordingly, the carbon fiber washer of the present invention has numerous advantages listed below: 
         [0014]    1. The carbon fiber washer of the present invention is not just high-temperature resisting, fatigue resisting, and weather proofing, but self-lubricating and abrasion resisting due to the short, discontinuous fiber of the outer most carbon fiber fabrics of the carbon fiber washer. 
         [0015]    2. The carbon fiber washer includes woven discontinuous fibers, so that while the carbon fiber washer is worn and a part of carbon fibers are abrade or torn, other carbon fibers will not be affected. As a result, the entire structure will not be loosened or delaminated, so as to prolong the service life of the carbon fiber washer. 
         [0016]    3. The carbon fiber washer of the present invention can be widely applied to various fields according to its carbonization ratios, such as implementing highly carbonized carbon fiber washer into automobile transmissions as gaskets, fishing reels, or other machines or apparatuses having highly rotating gears, and implementing mid-carbonized carbon fiber washer into machines having gears operating in lower rotating speed, such as food-grade processing machines, rather than using lubricating oils which may remain in the foods during the process. Low carbonized carbon fiber washers require lower manufacturing costs. Besides, low carbonized carbon fiber washers can not just be working with low speed gears, but be used as screw washers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings. 
           [0018]      FIG. 1  is an SEM image of the carbon fiber washer; 
           [0019]      FIG. 2  is another SEM image of the carbon fiber washer; 
           [0020]      FIG. 3  is an SEM image of the cross-section of the carbon fiber washer; 
           [0021]      FIG. 4  is another SEM image of the cross-section of the carbon fiber washer; 
           [0022]      FIG. 5  is a schematic diagram illustrating a second preferred embodiment of the present invention; 
           [0023]      FIG. 6  shows a TGA result of samples of the present invention being tested under 400° C.; 
           [0024]      FIG. 7  shows a TGA result of samples of the present invention being tested under 500° C.; and 
           [0025]      FIG. 8  is a schematic diagram showing a conventional woven carbon fiber washer with continuous carbon fibers. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    The structure and technical features of the present invention will now be described in considerable detail with reference to some embodiments and the accompanying drawings thereof, so that the present invention can be easily understood. 
         [0027]    A carbon fiber washer is provided according to the present invention and includes a carbon fiber fabric  11  made of a plurality of fiber bundles  111  being woven, and each of the plurality of fiber bundles is made of a plurality of discontinuous fibers  1111 . Preferably, the fiber bundles  111  are woven in both latitude and longitude directions as shown in the SEM images of  FIG. 1  to  FIG. 4 . 
         [0028]    A method for producing a carbon fiber fabric  11  is further provided and includes the following steps: 
         [0029]    (1) Providing a plurality of non-carbonized discontinuous fibers and twisting, bundling the discontinuous fibers into lines, in which the discontinuous fibers can be acrylic fibers. 
         [0030]    (2) Interlacing and weaving the bundled non-carbonized discontinuous fibers by different methods to form a non-carbonized fiber fabric having various kinds of weaving patterns; the weaving method mentioned above is not limited to any specific way. Nonetheless, shuttleless weaving, such as plain weaving, is preferable; when the carbon fiber washer is formed by shuttleless weaving, the transmission of transverse shear stress generated during operation can be cut-off, thereby preventing damages. 
         [0031]    (3) Carbonizing the non-carbonized fiber fabric by applying a temperature ranging from 400°˜3500° C. for forming the carbon fiber fabric  11 , where, preferably, the carbonization ratio of the carbon fiber fabric can be ranged from 10% to 95%. 
         [0032]    Referring to  FIG. 3  to  FIG. 4 , the carbon fiber fabrics  11  of the first preferred embodiment of the present invention made by the aforementioned method are then superimposed to each other side by side to form a laminated structure. The carbon fiber fabrics  11  are bonded by a bonding material  20 . The bonding material  20  can be thermal-plastic resin such as polyester and polysulfone resin, or thermal-setting resin such as epoxy and phenolic resin. A hot-pressing machine is applicable to bond the carbon fiber fabrics  11  with the bonding material  20  by applying a pressure of 45˜250 kg/cm 2  and a temperature not more than 350° C. Further, the carbon fiber fabrics  11  are bonded with the bonding material  20  having a predetermined thickness by laminating with hot-pressing, so that the bonding material  20  can be melted and infiltrated into the discontinuous fibers of the carbon fiber fabric  11 , as shown in  FIG. 3  to  FIG. 4 . The bonding material  20  may partially infiltrate or impregnate the spaces between the discontinuous fibers  1111 , and the outer surface of the carbon fiber washer  10  includes at least a portion not infiltrated with the bonding material  20 . After hardening of the bonding material  20  by, for instance, thermal-setting, each two carbon fiber fabrics  11  are bonded and combined to each other, thereby providing strong structural rigidity and preventing delaminating. The predetermined thickness mentioned above depends on the thickness of the carbon fiber fabric  11 , the volume percentage, and the impregnation ratio to be reached. For instance, if the impregnation ratio impregnated with the bonding material  20  to be reached is 40%˜80%, the predetermined thickness of the bonding material  20  can be ranged from 40vt % to 80vt % of the carbon fiber fabric  11 . The bonding material  20  can be partially infiltrated into the carbon fiber fabrics  11  by coating, spraying or film stacking. Hence, the carbon fiber washer of the present embodiment provides self-lubricating and abrasion resisting due to the short, discontinuous fibers of the carbon fiber fabric  11  located at the outermost layer of the carbon fiber washer. 
         [0033]    In light of mass-producing the carbon fiber washer of the present invention, the materials of the carbon fiber washer including the carbon fiber fabrics  11  and the bonding material  20  can be prepared as rolls, such that a roll-to-roll process can be performed to produce carbon fiber washers having laminated structures. The material of the bonding material  20  can be selected according to the surface property of the bonding object. High pressure and high temperature are applied during the bonding process, thereby strengthening the structure of the laminated carbon fiber washer. The laminated structure having the carbon fiber fabrics  11  and the bonding materials  20  will be formed in rolls, and then further cutting processes such as stamping and cropping can be applied to cut out the carbon fiber washers  10 . 
         [0034]    The second preferred embodiment of the present invention as shown in  FIG. 5  is that other than combining each two carbon fiber fabrics  11  with the bonding material  20 . The carbon fiber washer may further includes a supporting material disposed between two of the bonding materials, each of the bonding materials is disposed between one of the carbon fiber fabrics and the supporting material, and the outmost layers of the carbon fiber washer are the two of the carbon fiber fabrics. The carbon fiber washer  10  includes materials combined in a side-to-side order of carbon fiber fabric  11 , bonding material  20 , supporting material  30 , bonding material  20 , and carbon fiber fabric  11 . Because the thickness of one single carbon fiber fabric  11  is thin and is utilized for lubricating against other mechanical components during operation, the supporting material  30  can be applied for thickening to strengthen the carbon fiber washer  10 . The supporting material  30  can be carbon fiber fabric, thin fiber fabric, basalt fiber fabric, or glass fiber fabric. A sandwich structure of the carbon fiber washer  10  of the present invention is formed while the carbon fiber washer  10  contains three or more laminas, in which the carbon fiber fabrics  11  are located to be the outer most layers of the carbon fiber washer  10 , and the other supporting materials  30  (which might contain one single lamina or laminas) are included at the inner side of the carbon fiber washer  10 . 
         [0035]    The followings are results showing benefits of the present invention, such as abrasion resisting, self-lubricating and thermal conducting. Referring to Table 1 and Table 2 below, illustrating physical properties of samples produced from the method for producing the carbon fiber washer of the present invention. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Carbonization 
                   
                   
                 Warp 
               
               
                   
                 temperature 
                 Thickness 
                 Basis weight 
                 density 
               
               
                 Sample code 
                 (° C.) 
                 (mm) 
                 (g/m 2 ) 
                 (/inch) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 CF-1001-T 
                 ~1085 
                 0.6 
                 260 
                 46 
               
               
                 CF-1003-T 
                 ~1075 
                 0.48 
                 150 
                 50 
               
               
                 CF-1001-Z 
                 1080~1090 
                 0.55 
                 300 
                 46 
               
               
                 CF-1003-Z 
                 1070~1090 
                 0.48 
                 170 
                 50 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                   
                 Latitude 
                   
                   
               
               
                   
                   
                 density 
                 Number of 
                 Thermal conductivity 
               
               
                   
                 Sample code 
                 (/inch) 
                 Laminas 
                 (W/cm · ° C.) 
               
               
                   
                   
               
             
             
               
                   
                 CF-1001-T 
                 28 
                 5 
                 4.98 
               
               
                   
                 CF-1003-T 
                 28 
                 3 
                 4.54 
               
               
                   
                 CF-1001-Z 
                 28 
                 5 
                 4.64 
               
               
                   
                 CF-1003-Z 
                 28 
                 3 
                 4.47 
               
               
                   
                   
               
             
          
         
       
     
         [0036]    The thermal conductivities of the samples are around 5 (W/cm·° C.), proving that the heats generated from physical frictions and abrasions during operation can be rapidly conducted and dissipated, thereby preventing damages caused by high temperatures of either the operating machine or the fibers. Please refer to  FIG. 6  to  FIG. 7 , which show TGA (TGA Q500) results of the samples listed in Table 1 and Table 2 being tested under 400° C. and 500° C. respectively. The weight percent losses of the samples under 400° C. are less than 3%, and the weight percent losses of the samples under 500° C. are less than 18%, which means that the quality of the samples are stable under high temperatures; the structure and the fibers are not easily damaged. 
         [0037]    Referring to Table 3 below, the dynamic and static friction coefficients, abrasions, and the heat distortion temperatures of the samples are tested under the ASTM D1894, ASTM D3884, and ASTM D648 standard test methods. According to the testing results showing the static and dynamic friction coefficients of the samples, the carbon fiber structure woven with discontinuous fibers of the present invention indeed provides self-lubricating effects. Additionally, the carbon fiber washer  10  formed with discontinuous fibers is high temperature and abrasion resisting according to the test results below. 
         [0000]    
       
         
               
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                   
                 Static 
                 Dynamic 
                   
                   
               
               
                   
                 friction 
                 friction 
                 Abrasion 
                 Heat distortion 
               
               
                 Sample code 
                 coefficient 
                 coefficient 
                 (g) 
                 temperature (° C.) 
               
               
                   
               
             
             
               
                 CF-1001-T 
                 0.41 
                 0.41 
                 0.3318 
                 157.0 
               
               
                 CF-1003-T 
                 0.27 
                 0.27 
                 0.0468 
                 161.1 
               
               
                 CF-1001-Z 
                 0.27 
                 0.27 
                 0.1521 
                 172.6 
               
               
                 CF-1003-Z 
                 0.41 
                 0.41 
                 0.2568 
                 157.8 
               
               
                   
               
             
          
         
       
     
         [0038]    According to the test results above, the structure woven from discontinuous carbon fibers of the present invention is not only self-lubricating, abrasion and high temperature resisting, but with outstanding structural stability; while a part of the carbon fibers are broken, those broken carbon fibers will not affect the stability of the entire woven fiber structure, so that the structure will not be easily loosened or delaminated, so as to prolong the service life of the carbon fiber washer of the present invention. 
         [0039]    Referring to Table 4 below showing abundance of elements under different carbonization ratios of sample code CF-1001-Z of the present invention carbonized with different carbonization temperatures. Carbon fiber washers carbonized under lower temperatures have more functional groups to be more easily bonding with bonding materials like resins, so that the structure will not be easily delaminated. 
         [0000]    
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 4 
               
               
                   
               
               
                   
                   
                   
                 Nitrogen 
                 Carbon 
                 Hydrogen 
               
               
                 Sample 
                 Carbonization 
                 Carbonization 
                 abundance 
                 abundance 
                 abundance 
               
               
                 code 
                 temperature° C. 
                 ratio 
                 N % 
                 C % 
                 H % 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 CF-1001-Z 
                 1080~1090 
                 85 
                 6.604 
                 84.505 
                 1.056 
               
               
                 CF-1001-Z 
                 850 
                 70 
                 12.808 
                 69.986 
                 1.768 
               
               
                   
               
             
          
         
       
     
         [0040]    The carbon fiber washer of the present invention can be widely applied to various fields according to its carbonization ratios. For instance, highly carbonized carbon fiber washers (carbonization ratio ranged between60%˜90%) can be implemented into automobile transmissions as gaskets, fishing reels, or other machines or apparatuses having highly rotating gears. Additionally, mid-carbonized carbon fiber washer (carbonization ratio ranged between 30%˜60%) can be implemented into machines having gears operating in lower rotating speed, such as food-grade processing machines, rather than using lubricating oils which may remain in the foods during the process. Low carbonized carbon fiber washers (carbonization ratio ranged between 10%˜30%) can not just be working with low speed gears, but be used as screw washers.