Patent Publication Number: US-2009224489-A1

Title: Oil seal

Description:
FIELD OF THE INVENTION 
     The present invention relates to an oil seal used in the oil hydraulic mechanics, and more particularly to an oil seal which has at least two seal components and two seal lips. 
     BACKGROUND OF THE INVENTION 
       FIG. 1  illustrates a section view of the conventional oil seal. The oil seal  1  comprises an annular casing  11 , a seal lip  12  and a seal component  13 . 
     The annular casing  11  includes an outer surface of wall  111  and a spindle hole formed at the center of the annular casing  11 . The spindle hole of annular casing  11  is provided for a shaft  2  passing through the annular casing  11 . The annular casing  11  is operable to mount the seal component  13 . 
     The seal lip  12  is extended circularly from one side of the annular casing  11  towards the axial direction of the shaft  2 . The seal lip  12  firmly encapsulates the annular casing  11  and the shaft  2  for preventing the lubricating oil  20  leaking from the oil seal  1 . 
     The seal component  13  is mounted on the annular casing  11  and extended from the annular casing  11  towards the axial direction of the shaft  2 . A container chamber  110  is formed by the annular casing  11 , the seal component  13  and the shaft  2 , and the container chamber  110  can contain a lubricating oil  20  inside the oil seal  1 . 
     When the shaft  2  passes through the spindle hole of the annular casing  11  and moved along the axial direction of the shaft  2  back and forth, because the shaft  2  is encapsulated firmly by the seal lip  12  and the seal component  13 , the lubricating oil  20  can be remained at the container chamber  110  and not leaking out of the oil seal  1 . 
     When the seal component  13  is damaged and the sealing ability decreased due to usage for a long time, the lubricating oil  20  adhered the shaft  2  may leak from the seal component  13  to the outside of the oil seal  1 , and it results in decreasing of the efficiency of the oil seal  1  and lake of the lubricating oil  20  on the shaft  2 . 
     SUMMARY OF THE INVENTION 
     Therefore, it is one of objectives of the present invention to provide an oil seal which prevents the leakage of the lubricating oil more effectively and has improved endurability. 
     The present invention provides an oil seal for preventing oil leakage and adapted to fit a shaft. The oil seal comprises an annular casing, a first seal component, a second seal component, a first seal lip and a second seal lip. The annular casing has a spindle hole at the center for the shaft passing through the annular casing. The first seal component is mounted on the annular casing. The second seal component is mounted on the annular casing and used for preventing a lubricating oil leaking from the first seal component. The first seal lip is disposed on the first side of the annular casing and used for preventing the lubricating oil leaking from the first side of the annular casing. The second seal lip is disposed on the second side of the annular casing for preventing the dust from entering the oil seal. The second side is opposite to the first side. 
     As described above, when the first seal component or first lip can not firmly encapsulates the shaft for preventing the lubricating oil from leaking due to decreasing of sealing ability, the second seal component can further exert the sealing ability to prevent the lubricating oil leaking out of the oil seal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention together with features and advantages thereof may best be understood by reference to the following detailed description with the accompanying drawings in which: 
         FIG. 1  illustrates a sectional view of the conventional oil seal; 
         FIG. 2  illustrates a section view of the first embodiment of the oil seal in accordance with the present invention; 
         FIG. 3  illustrates a section view of the second embodiment of the oil seal in accordance with the present invention; and 
         FIG. 4  illustrates a section view of the third embodiment of the oil seal in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     To make it easier for our examiner to understand the present invention, the following detailed description with reference to the accompanying drawings of embodiments are given for example, but such preferred embodiment is not intend to limit the scope of the present invention. For simplicity, like numerals are used for like elements as described in the specification of the present invention. 
       FIG. 2  illustrates a section view of the first embodiment of the oil seal in accordance with the present invention. The oil seal  3  comprises an annular casing  31 , a first seal component  33 , a second seal component  34 , a first seal lip  35  and a second seal lip  36 . 
     The annular casing  31  includes an outer surface of wall  312 , a first side  200 , a second side  300  and a spindle hole formed at the center of the annular casing  31 , wherein the second side  300  is opposite to the first side  200 . The spindle hole of annular casing  31  is provided for a shaft  4  passing through the annular casing  31 . The annular casing  31  is operable to mount the first seal component  33  and the second seal component  34 . Preferably, the annular casing  31  can be a metal cylinder, and the annular casing  31  can further comprise multiple constraint components used for constraining the first seal component  33  and the second seal component  34 . The first seal component  33  and the second seal component  34  can be extended to the same direction or the different direction. 
     The first seal lip  35  is extended circularly from the first side  200  of the annular casing  31  towards the axial direction of the shaft  4 . The second seal lip  36  is extended circularly from the second side  300  of the annular casing  31  towards the axial direction of the shaft  4 . The first seal lip  35  is used for preventing the lubricating oil  40  leaking from the oil seal  3 , and the second seal lip  36  is used for preventing the dust from entering the oil seal  3 . Preferably, the first seal lip  35  and the second seal lip  36  can be made from elastic material. Besides, the first seal lip  35  and the second seal lip  36  can be integrally formed if necessary. 
     The first seal component  33  has first fixed portion  331  and a first converged portion  332 . The first fixed portion  331  is mounted into the annular casing  31 , and the first converged portion  332  is extended from the first fixing portion  331  towards the axial direction of the shaft  4 . The first seal component  33  is used for preventing the leakage from the lubricating oil  40 . Preferably, the first seal component  33  can be made from teflon, polyurethane, polyacrylate, fluorosilicone or materials used for oil seal. 
     The second seal component  34  includes a second fixed portion  341  and a second converged portion  342 . The second fixed portion  341  is mounted into the annular casing  31 , and the second converged portion  342  is extended from the second fixed portion  341  towards the axial direction of the shaft  4 . The second seal component  34  is used for preventing a lubricating oil  40  leaking from the first seal component  33 . A container chamber  311  is formed by the annular casing  31 , a first seal component  33 , a second seal component  34  and a shaft  4 , and the container chamber  311  can contain a lubricating oil  40  inside the oil seal  3 . Preferably, the second seal component  34  can be made from teflon, polyurethane, polyacrylate, fluorosilicone or materials use for oil seal. Preferably, the first seal component  33  and the second seal component  34  can be extended towards the same direction or different directions. 
     When the shaft  4  passes through the spindle hole of the annular casing  31  and moved along the axial direction of the shaft  4  back and forth, because the shaft  4  is encapsulated firmly by the first seal lip  35  and the first seal component  33 , the lubricating oil  40  can be remained at the container chamber  311  and not leak out of the oil seal  3 . 
     When the first seal component  33  is damaged and the sealing ability decreased, the lubricating oil  40  adhered to the shaft  4  may leak from first seal component  33  and moved towards the second seal component  34 , the second seal component  34  can exert the sealing ability to prevent the lubricating oil  40  leaking out of the oil seal  3 . 
       FIG. 3  illustrates a section view of the second embodiment of the oil seal in accordance with the present invention. The oil seal  3  comprises an annular casing  31 , a first seal component  33 , a second seal component  34 , a first seal lip  35  and a second seal lip  36 . 
     The annular casing  31  includes an outer surface of wall  312 , an inner side of wall  313 , a first side  200  and a second side  300 , wherein the second side  300  is opposite to the first side  200 . The spindle hole of the annular casing  31  is provided for a shaft  4  passing through the annular casing  31 . The annular casing  31  is operable to mount the first seal component  33  and the second seal component  34 . Preferably, the annular casing  31  can be a metal cylinder and the annular casing  31  can further comprise multiple constraint components used for constraining the first seal component  33  and the second seal component  34 . 
     The annular casing  31  further includes a first constraint component  314 , a second constraint component  315 , a third constraint component  317 , a first constraint groove  318 , a second constraint groove  319 , a first seal component  33  and a second seal component  34 . 
     The first seal lip  35  is extended circularly from the first side  200  of the annular casing  31  towards the axial direction of the shaft  4 . The second seal lip  36  is extended circularly from the second side  300  towards the axial direction of the shaft  4 . The first seal lip  35  is used for preventing the lubricating oil  40  leaking from the oil seal  3 , and the second seal lip  36  is used for preventing the dust from entering the oil seal  3 . The first seal lip  35  and the second seal lip  36  are integrally formed and firmly encapsulating the annular casing  31 . Preferably, the first seal lip  35  and the second seal lip  36  can be made from elastic material. 
     The first constraint component  314 , the second constraint component  315  and the third constraint component  317  are extended circularly from the inner side of wall  313  towards the axial direction of the shaft  4 . The second constraint component  315  is disposed between the first constraint component  314  and the third constraint component  317 . Preferably, the first constraint component  314 , the second constraint component  315  and the third constraint component  317  can be made from metal material. 
     The first constraint groove  318  is formed between the first constraint component  314  and the second constraint component  315 , and the second constraint groove  319  is formed between the second constraint component  315  and the third constraint component  317 . 
     The first seal component  33  has a first fixed portion  331  and a first converged portion  332 . The first fixed portion  331  is inserted into the first constraint groove  318 , and the first converged portion  332  is extended circularly from the first fixed portion  331  towards the shaft  4 . Preferably, the first seal component  33  is made from teflon, polyurethane, polyacrylate, fluorosilicone or materials used for oil seal. 
     The second seal component  34  has a second fixed portion  341  and a second converged portion  342 . The second fixed portion  341  is inserted into the second constraint groove  319 , and the second converged portion  342  is extended circularly from the second fixed portion  341  towards the shaft  4 . The first seal component  33  and the second seal component  34  are extended towards the same direction. A container chamber  311  is formed by the annular casing  31 , a first seal component  33 , a second seal component  34  and a shaft  4  for containing a lubricating oil  40  inside the oil seal  3 . Preferably, the second seal component  34  is made from teflon, polyurethane, polyacrylate, fluorosilicone or materials used for oil seal. 
     The second constraint component  315  further has a press edge  316  which is extended circularly from one side of the second constraint component  315  towards the axial direction of the shaft  4 . Preferably, the press edge  316  is used for enhancing the pressing ability of the second constraint component  315  for constraining the first seal component  33 . 
     When the shaft  4  passes through the spindle hole of the annular casing  31  and moved along the axial direction of the shaft  4  back and forth, because the shaft  4  is encapsulated firmly by the first seal lip  35  and the first seal component  33 , the lubricating oil  40  can be remained at the container chamber  311  and not leak out of the oil seal  3 . 
     When the first seal component  33  is damaged and the sealing ability decreased, the lubricating oil  40  adhered to the shaft  4  may leak from first seal component  33  and moved towards the second seal component  34 , the second seal component  34  can exert the sealing ability to prevent the lubricating oil  40  from leaking out of the oil seal  3 . 
       FIG. 4  illustrates a section-view of the third embodiment of the oil seal in accordance with the present invention. The oil seal  3  comprises an annular casing  31 , a first seal component  33 , a second seal component  34 , a first seal lip  35  and a second seal lip  36 . The difference between the third embodiment and second embodiment is that the first seal component  33  and the second seal component  34  are extended to different directions. 
     While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.