Patent Publication Number: US-6984115-B1

Title: Axial sealing structure of scroll compressor

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates in general to an axial sealing structure of a scroll compressor, and more particularly, to an axial sealing structure of a scroll compressor with a floating seal member, capable of both simplifying and reducing the difficulty of the assembling procedure of the scroll compressor. Thereby, a scroll compressor has a better product quality and a lower production cost. 
   A typical scroll compressor includes a fixed scroll and an orbiting scroll. The orbiting scroll revolves about the fixed scroll. The fixed scroll and the orbiting scroll each has a spiral wrap inter-fitting each other to allow working fluid entering a compression pocket through a suction port. The continuous revolutions of the orbiting scroll compress the working fluid until the working fluid is discharged from an inner discharge port of the fixed scroll. During the compression process the volume of the working fluid is reduced while the pressure thereof is increased. Axial force, radial force and tangential force appear in the compression process. The axial force tends to cause axial separation of these two scroll members. The radial and tangential forces generate biasing torques. The axial, radial and tangential forces cause leakage from the end panels or the side surfaces of the wraps. How to enhance the volume efficiency of the compressor has thus become an important topic in this field. 
   A conventional axial sealing structure of a scroll compressor, for example, U.S. RE 35216, comprises a fixed scroll member with an annular cavity formed on the back thereof inside which an annular floating seal member is disposed. The floating seal member has at least one outer lip seal attached the outer wall of the annular cavity and at least one inner lip seal attached the inner wall of the annular cavity. A working fluid under an intermediate pressure flows from a compression pocket into the annular cavity through an orifice and builds an intermediate pressure inside the annular cavity. The fixed scroll member is thus axially biased against an orbiting scroll member by the forces created by discharge pressure acting on the central portion of the fixed scroll member and those created by intermediate pressure acting on the bottom of the cavity. The axial sealing is thereby achieved. 
   However, there is a problem still existing in the conventional axial sealing structure. Because the floating seal member is inserted downward into the annular cavity on the back of the fixed scroll member, both the outer lip seal and the inner lip seal secured to the floating seal member are flipped upward. But, the outer lip seal is to isolate the intermediate pressure working fluid from the low pressure working fluid. The outer lip seal has to be disposed downward to have its isolating function. Therefore, after the installation of the floating seal member, the outer lip seal has to be further reoriented downward. To simplify the assembling procedure for increasing the production speed, it is therefore necessary for manufacturers to design a special tool. The special tool is able to hold the outer lip seal downward and to deform the outer lip seal for decreasing the circumference of the outer lip seal. The special tool holding the outer lip seal and the floating seal member are simultaneously inserted into the annular cavity. The special tool is then withdrawn from the annular cavity. In summary, although the conventional art can produce a scroll compressor with a floating seal member, the manufacture procedure thereof is tedious and complicated. The conventional art has to consume a longer labor hours to produce a scroll compressor with a floating seal. The fabrication cost of the conventional art is inevitably high. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention provides an axial sealing structure of a scroll compressor. Two seal elements are respectively secured to a floating seal member and a fixed scroll. The present invention is capable of both simplifying and reducing the difficulty of the assembling procedure of the scroll compressor. A scroll compressor utilizing the present invention has a better product quality and a lower production cost. 
   The axial sealing structure of a scroll compressor of the present invention has the floating seal member disposed between a partition and the top of the fixed scroll. An intermediate pressure room is formed between the floating seal member and the fixed scroll to force the fixed scroll to closely attach an orbiting scroll, so as to enhance the volume efficiency of the compressor. 
   The axial sealing structure of a scroll compressor of the present invention guides the intermediate pressure working fluid into the intermediate pressure room to force the fixed scroll to move downward such that the axial force and biasing torque applied to the fixed scroll during compression are overcome. The lifetime of the scroll compressor is effectively extended. 
   According to the present invention, the axial sealing mechanism of the scroll compressor comprises a housing, a scroll device, and a floating seal member with a recess portion and a central channel. The housing includes a first shell and a second shell. The first shell has a receiving chamber. A partition is disposed inside the receiving chamber. The scroll device includes a fixed scroll and an orbiting scroll. A plurality of compression pockets is formed between the fixed scroll and the orbiting scroll. The fixed scroll has a protruding portion with a plurality of orifices. The recess portion of the floating seal member receives the protruding portion of the fixed scroll. Seal elements are respectively secured to the floating seal member and the fixed scroll. An intermediate pressure room is thereby formed between the float seal element and the fixed scroll. 
   The objectives of the present invention will become obvious to those of ordinary skill in the art after reading the following detailed description of preferred embodiments. 
   It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These as well as other features of the present invention will become more apparent upon reference to the drawings therein: 
       FIG. 1  is a partial cross sectional view of a scroll compressor utilizing a first embodiment of the present invention. 
       FIG. 2  is an enlarged view of the portion A of  FIG. 1 . 
       FIG. 3  is an enlarged view similar to  FIG. 2 , illustrating the operating condition of the present invention. 
       FIG. 4  is a partial cross sectional view of a scroll compressor utilizing a second embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
   Referring to  FIG. 1  and  FIG. 2 , an axial sealing structure of a scroll compressor in accordance with the present invention includes a housing  10 , a scroll device  20 , and a floating seal member  30 . 
   The housing  10  comprises a first shell  11  and a second shell  12 . Both the first shell  11  and the second shell  12  have a hollow cavity formed therein. The first shell  11  is secured to the top of the second shell  12  by means of a plurality of fastening members, or by other methods such as a welding or a soldering process. The hollow cavity of the first shell  11  defines a receiving chamber  13 . Inside the receiving chamber  13  a partition  14  is installed to separate the inner space of the housing  10  into a high-pressure zone  15  and a low-pressure zone  16 . The partition  14  is preferably a circular plate with a circular opening  141  bored in the middle thereof. The circular opening  141  is the inlet of the high-pressure zone  15 . The high-pressure zone  15  further connects to a gas outlet  17  formed at one side of the first shell  11 . In addition, the second shell  12  has a working fluid inlet (not shown in the figures) bored at one side thereof. The second shell  12  further comprises an electric motor, a transmission mechanism, and other supporting elements installed inside the hollow cavity thereof. The electric motor has a transmission shaft  18  extending from the center thereof. 
   The scroll device  20  includes a fixed scroll  21  and an orbiting scroll  22 . The fixed scroll  21  has a spiral wrap  211  formed at the bottom thereof and a protruding portion  23  formed in the middle thereof. The protruding portion  23  comprises a discharge passageway  24  at the center thereof. The discharge passageway  24  is constituted by two adjoining circular holes with different diameters. The diameter of the lower circular hole is smaller than that of the upper circular hole. A plurality of orifices  25  is bored through the protruding portion  23  at suitable places. Similarly, the orbiting scroll  22  has a spiral wrap  221  formed on the top thereof, which inter-fits the spiral wrap  211  of the fixed scroll  21 . A plurality of compression pockets  26  is thereby formed between the spiral wraps  211 ,  221 . The orbiting scroll  22  further comprises a shaft hole  27  formed at the bottom thereof. The shaft hole  27  is used to install a bearing and an eccentric device for connecting the transmission shaft  18  to the orbiting scroll  22 . 
   The floating seal member  30  is disposed between the partition  14  and the fixed scroll  20 . The floating seal member comprises an inner ring  31 , an outer ring  32 , which are located at the bottom thereof, a top barrel  35 , and an annular contact surface  36 , which are located at the top thereof. The top barrel  35  protrudes into the circular opening  141  of the partition  14 . The inner ring  31  extends into the discharge passageway  24  of the fixed scroll  21 . The interior spaces of the inner ring  31  and the top barrel  35  constitute a central channel  34 , which is able to connect the discharge passageway  24  to the circular opening  141  of the partition  14 . The inner ring  31  and the outer ring  32  define a recess portion  33 , which is able to receive the protruding portion  23  of the fixed scroll  21 . The contact surface  36  tightly engages the bottom of partition  14  in order to prevent the high-pressure working fluid of the high-pressure zone  15  from leakage during compression. The narrow width of the contact surface  36  ensures that the contact surface  36  is under a sufficient pressure to firmly press against the bottom of the partition  14  during compression. 
   Further, at least a first seal element  37  is disposed between the inner periphery of the outer ring  32  of the floating seal member  30  and the outer wall of the protruding portion  23  of the fixed scroll  21 . Similarly, at least a second seal element is disposed between the exterior periphery of the inner ring  31  and the inner wall of the discharge passageway  24  of the fixed scroll  21 . The sealing elements, in preferred embodiments, comprise a lip seal. The lip seal, however, may be substituted with other devices, which perform essentially the same function. These other devices may include, but not limited to, an o-ring gasket, a u-shaped sealing ring, a mechanical seal. In preferred embodiments, the exterior portion of the first seal element  37  is secured to the bottom of the outer ring  32  of the floating seal member  30  by means of a fixing ring and a plurality of screws. The interior portion of the first seal element  37  is wider than a gap between the floating seal member  30  and the protruding portion  23  of the fixed scroll  21 . The interior portion of the first seal element  37  installed is therefore under a resilient force and presses against the outer wall of the protruding portion  23 . Similarly, the exterior portion of the second seal element is secured to the end surface of the protruding portion  23  of the fixed scroll  21  by means of a fixing ring and a plurality of screws. The interior portion of the second element, under a resilient force, presses against the periphery of the inner ring  31 . Furthermore, the orifice  25 , which is bored through the protruding portion  23 , connects the compression pockets  26  to the recess portion  33 , and allows working fluid under an intermediate pressure to flow into the recess portion  33 . Because the first seal element  37  isolates the recess portion  33  from the low-pressure zone  16  and the second seal element isolate the recess portion  33  from the higher discharge pressure, an intermediate pressure room  38  is thereby formed during compression, between the floating sealing member  30  and the protruding portion  23  of the fixed scroll  21 . 
   To assemble a scroll compressor utilizing the present invention, the first seal element  37  and the second seal element are respectively secured to the outer ring  32  and the end surface of the protruding portion  23  of the fixed scroll  21 . Further, the floating seal member  30  is installed onto the top of the fixed scroll  21 . Because the first seal element  37  is fixed to the floating seal member  30 , the downward movement of the first seal element  37  relative to the fixed scroll  21  during the installation of the floating seal member  30  will bend the interior portion of the first seal element  37  upward. Similarly, because the second seal element is fixed to the protruding portion  23  of the fixed scroll  21 , the interior portion of the second seal element will be pushed downward during the downward movement of the floating seal member  30  relative to the fixed scroll  21 . Consequently, both the first seal element  37  and the second seal element are installed correctly with their interior portions disposed along their desired directions. It is unnecessary for a worker to use a special tool to install the floating seal element  30  of the present invention. The present invention simplifies a scroll compressor&#39;s assembling procedure and reduces the difficulty of the assembling procedure. Thereby, a scroll compressor utilizing the present invention has a better product quality and a lower production cost. 
   Referring to  FIG. 3 , by utilizing the aforementioned assembly, when the electric motor drives the orbiting scroll  22  to revolve, the low-pressure working fluid from the working fluid inlet of the second shell  12  will be sucked into the compression pockets  26  formed between the spiral wrap  211  of the fixed scroll  21  and the spiral wrap  221  of the orbiting scrolls  22 . The revolution of the orbiting scroll  22  further moves the working fluid from the periphery of the scroll device  20  towards the center thereof. During compression the volume of the working fluid is gradually reduced while the pressure thereof gradually increases. The plurality of orifices  25  allows working fluid under an intermediate pressure to flow into the intermediate pressure room  38 . The air pressure of the intermediate pressure room  38  pushed the floating seal member  30  upward against the bottom of the partition  14 . The air pressure of the intermediate pressure room  38  further presses the fixed scroll  21  downward to closely attach the orbiting scroll  22 , so as to achieve the sealing effect. 
   Referring to  FIG. 4 , a cross sectional view of a second embodiment of an axial sealing structure of a scroll compressor in accordance with the present invention is shown. The first shell  11  has a partition  14  extends from the receiving chamber  13  thereof. In the present embodiment, the partition  14  is a cylinder with a circular opening  141  formed at the center thereof. The opening  141  connects to the gas outlet  17  of the first shell  11 . The inner diameter of the opening  141  corresponds with the exterior diameter of the top barrel  35  of the floating seal member  30 . The contact surface  36  of the floating seal member  30  is opposite to the end surface of the cylindrical bottom of the partition  14 . 
   In summary, the axial sealing structure of a scroll compressor as provided has at least three merits. First, two seal elements are respectively secured to the floating seal member and the fixed scroll. This arrangement is capable of both simplifying a scroll compressor&#39;s assembling procedure and reducing the difficulty of the assembling procedure. A scroll compressor utilizing the present invention has a better product quality and a lower production cost. Second, the axial sealing structure of a scroll compressor of the present invention has the floating seal member disposed between a partition and the top of the fixed scroll. An intermediate pressure room is formed between the floating seal member and the fixed scroll to force the fixed scroll to closely attach an orbiting scroll, so as to enhance the volume efficiency of the compressor. Third, the present invention guides the intermediate pressure working fluid into the intermediate pressure room to force the fixed scroll to move downward such that the axial force and biasing torque applied to the fixed scroll during compression are overcome. The lifetime of the scroll compressor is effectively extended. 
   While an illustrative and presently preferred embodiment of the invention has been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.