Patent Publication Number: US-11655721-B2

Title: Turbocharger including a sealing assembly

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a turbocharger including a sealing assembly. 
     2. Description of the Related Art 
     Turbochargers receive exhaust gas from an internal combustion engine of a vehicle and deliver compressed air to the internal combustion engine. Turbochargers are used to increase power output of the internal combustion engine, decrease fuel consumption of the internal combustion engine, and reduce emissions produced by the internal combustion engine. Delivery of compressed air to the internal combustion engine by the turbocharger allows the internal combustion engine to be smaller, yet able to develop the same or similar amount of horsepower as larger, naturally aspirated internal combustion engines. Having a smaller internal combustion engine for use in the vehicle reduces the mass and aerodynamic frontal area of the vehicle, which helps reduce fuel consumption of the internal combustion engine and improve fuel economy of the vehicle. 
     Typical turbochargers include a shaft extending along an axis between a first shaft end and a second shaft end. Turbochargers further include a turbine wheel coupled to the first shaft end of the shaft, and a compressor wheel coupled to the second shaft end of the shaft. The turbine wheel and the compressor wheel are rotatable with the shaft. Specifically, the exhaust gas from the internal combustion engine, which would normally contain wasted energy, is used to drive the turbine wheel, which is used to drive the shaft and, in turn, the compressor wheel to deliver compressed air to the internal combustion engine. Typical turbochargers also include a bearing housing defining a bearing housing interior and disposed about the shaft, and a turbine housing defining a turbine housing interior and disposed about the turbine wheel. 
     In some turbochargers, a sealing assembly is included for sealing the bearing housing interior and the turbine housing interior. Typically, a lubricant is present in the bearing housing interior, and the sealing assembly limits the lubricant from entering the turbine housing interior. Moreover, the exhaust gas is typically present in the turbine housing interior and contains uncombusted carbon and corrosive by-products of combustion, and the sealing assembly limits the exhaust gas from interacting with the lubricant. However, sealing assemblies known in the art suffer from deficiencies, particularly relating to sealing the high temperature exhaust gases present in the turbine housing interior where the high temperature of the exhaust gas is transferred, particularly by conduction, to the bearing housing interior. 
     These deficiencies include, but not limited to, blowby of the exhaust gas from the turbine housing interior to the bearing housing interior, and leakage of the lubricant from the bearing housing interior to the turbine housing interior. Both blowby of the exhaust gas and leakage of the lubricant degrade the quality of the lubricant. Sealing assemblies known in the art lack temperature stability to reduce the blowby of the exhaust gas and the leakage of the lubricant, and thus decrease the life, durability, and reliability of the sealing assembly and of the turbocharger. Moreover, sealing assemblies known in the art attempting to address these deficiencies disadvantageously increase an axial length of the turbocharger. 
     As such, there remains a need to provide an improved sealing assembly for a turbocharger that limits blowby of the exhaust gas from the turbine housing interior to the bearing housing interior and limits leakage of the lubricant from the bearing housing interior to the turbine housing interior. 
     SUMMARY OF THE INVENTION AND ADVANTAGES 
     A turbocharger delivers compressed air to an internal combustion engine. The turbocharger includes a shaft extending along an axis between a first shaft end and a second shaft end. A turbine wheel is coupled to the first shaft end of the shaft. A bearing housing is disposed about the shaft, and the bearing housing defines a bearing housing interior. A turbine housing is disposed about the turbine wheel, and the turbine housing defines a turbine housing interior. The turbocharger also includes a sealing assembly for sealing the bearing housing interior and the turbine housing interior. 
     The sealing assembly includes a case disposed about the shaft. The case extends along the axis between a first case end proximate to the turbine wheel, and a second case end distal from the turbine wheel. The sealing assembly also includes a ring disposed between the shaft and the case such that the ring is unobstructed by the case radially between the shaft and the ring. The sealing assembly further includes a deformable component coupled to the second case end of the case and to the ring. The deformable component is moveable with the ring to seal the bearing housing interior and the turbine housing interior. 
     A lubricant may be present in the bearing housing interior, and the exhaust gas may be present in the turbine housing interior and may contain uncombusted carbon and corrosive by-products of combustion. The sealing assembly limits the high temperature exhaust gases that may be present in the turbine housing interior from being transferred, particularly by conduction, to the bearing housing interior. The sealing assembly also limits the blowby of the exhaust gas from the turbine housing interior to the bearing housing interior. Furthermore, the sealing assembly limits leakage of the lubricant from the bearing housing interior to the turbine housing interior. Therefore, the sealing assembly limits blowby of the exhaust gas and leakage of the lubricant from degrading the quality of the lubricant by reducing the uncombusted carbon and corrosive by-products of combustion in the exhaust gas from transferring to the lubricant. 
     More specifically, because the sealing assembly includes a ring disposed between the shaft and the case such that the ring is unobstructed by the case radially between the shaft and the ring, the sealing assembly is thermally stable at the high temperatures present during operation of the turbocharger such that sealing assembly is prevented from thermally degrading (e.g. melting). The ring being unobstructed by the case radially between the shaft and the ring results in the sealing assembly being able to lift-off close to the shaft, thus removing the need for an o-ring in contact with the shaft that is liable to thermally degrade. 
     Therefore, because the sealing assembly is prevented form thermally degrading, the sealing assembly reduces blowby of the exhaust gas and leakage of the lubricant, thus increasing the life of the sealing assembly and of the turbocharger by maintaining the quality of the lubricant. As such, the sealing assembly improves the durability and reliability of the turbocharger. Moreover, the sealing assembly is able to seal the bearing housing interior and the turbine housing interior without significantly increasing an axial length of the turbocharger. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
         FIG.  1    is a schematic illustration of a turbocharger having shaft extending along an axis between a first shaft end coupled to a turbine wheel and a second shaft end coupled to a compressor wheel, a bearing housing defining a bearing housing interior, and a turbine housing defining a turbine housing interior; 
         FIG.  2    is a cross-sectional view of the turbocharger, with the turbocharger including a sealing assembly including a case extending between first and second case ends, a deformable component, a ring, and an isolator; 
         FIG.  3    is a cross-sectional view of the turbocharger, with the sealing assembly including a sealing member, a seating groove, and a piston ring disposed at least partially in the seating groove; 
         FIG.  4    is a cross-sectional view of the turbocharger, with the sealing assembly including a bellow having a first bellow end extending radially away from the shaft and fixedly coupled to the second case end of the case, and having a second bellow end fixedly coupled to the ring to allow the bellow to be moveable with the ring; 
         FIG.  5    is a cross-sectional view of the turbocharger, with the sealing assembly including the second bellow end of the bellow extending radially inward toward the shaft; 
         FIG.  6    is a cross-sectional view of the turbocharger, with the second case end of the case extending radially inward toward the shaft and presenting a coupling surface to which the deformable component is coupled; 
         FIG.  7    is a perspective view of the second bellow end of the bellow, with the second bellow end of the bellow defining a plurality of holes; 
         FIG.  8    is a perspective view of the second bellow end of the bellow, with the second bellow end of the bellow defining a plurality of notches; 
         FIG.  9 A  is a perspective view of the second bellow end of the bellow, with an outer surface of the second bellow end of the bellow defining a plurality of grooves; 
         FIG.  9 B  is a perspective view of the second bellow end of the bellow, with an inner surface of the second bellow end of the bellow defining the plurality of grooves; 
         FIG.  10    is a perspective view of the second bellow end of the bellow, with the second bellow end of the bellow shaped to have a plurality of corrugations; and 
         FIG.  11    is a perspective view of the second bellow end of the bellow, with the second bellow end of the bellow shaped to have a plurality of protrusions. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the Figures, wherein like numerals indicate like parts throughout the several views, a turbocharger  10  is shown schematically in  FIG.  1   . The turbocharger  10  delivers compressed air to an internal combustion engine. The turbocharger  10  includes a shaft  12  extending along an axis A between a first shaft end  14  and a second shaft end  16 . It is to be appreciated that the first and second shaft ends  14 ,  16  need not be the exact terminuses of the shaft  12 . A turbine wheel  18  is coupled to the first shaft end  14  of the shaft  12 . A bearing housing  20  is disposed about the shaft  12 , and the bearing housing  20  defines a bearing housing interior  22 . A turbine housing  24  is disposed about the turbine wheel  18 , and the turbine housing  24  defines a turbine housing interior  26 . 
     It is to be appreciated that the turbocharger  10  may also include a compressor wheel  40 , and a compressor housing  42  defining a compressor housing interior  44  and disposed about the compressor wheel  40 , as shown in  FIG.  1   . Although not required, it is also to be appreciated that the turbine housing  24  may be a dual volute turbine housing, a twin scroll turbine housing, or a single inlet turbine housing. 
     The turbocharger  10  also includes a sealing assembly  28  for sealing the bearing housing interior  22  and the turbine housing interior  26 . The sealing assembly  28  includes a case  30  disposed about the shaft  12 . The case  30  extends along the axis A between a first case end  32  proximate to the turbine wheel  18 , and a second case end  34  distal from the turbine wheel  18 . It is to be appreciated that the first and second case ends  32 ,  34  need not be the exact terminuses of the case  30 . The sealing assembly  28  also includes a ring  36  disposed between the shaft  12  and the case  30  such that the ring  36  is unobstructed by the case  30  radially between the shaft  12  and the ring  36 . In other words, the case  30  is disposed radially between the shaft  12  and the ring  36 . As such, the case  30  is open or semi-open. The sealing assembly  28  further includes a deformable component  38  coupled to the second case end  34  of the case  30  and to the ring  36 . It is to be appreciated that the deformable component  38  may be freely rotatable relative either to the second case end  34  of the case  30 , to the ring  36 , or to both the second case end  34  of the case  30  and to the ring  36 , while still being coupled to the second case end  34  of the case  30  and to the ring  36 . The deformable component  38  is moveable with the ring  36  to seal the bearing housing interior  22  and the turbine housing interior  26 . 
     A lubricant may be present in the bearing housing interior  22 , and the exhaust gas may be present in the turbine housing interior  26  and may contain uncombusted carbon and corrosive by-products of combustion. The sealing assembly  28  limits the high temperatures that may be present in the exhaust gases in the turbine housing interior  26  from being transferred, particularly by conduction, to the bearing housing interior  22 . The sealing assembly also limits the blowby of the exhaust gas from the turbine housing interior  26  to the bearing housing interior  22 . Furthermore, the sealing assembly  28  limits leakage of the lubricant from the bearing housing interior  22  to the turbine housing interior  26 . Therefore, the sealing assembly  28  limits blowby of the exhaust gas and leakage of the lubricant from degrading the quality of the lubricant by reducing the uncombusted carbon and corrosive by-products of combustion in the exhaust gas from transferring to the lubricant. 
     Moreover, the sealing assembly  28  limits blowby of the exhaust gas into a crankcase of the internal combustion engine, which can then be recirculated into an intake system of the internal combustion engine. The lubricant, uncombusted carbon, and corrosive by-products of combustion that may be recirculated into the intake system may deposit themselves on components of the intake system, thus decreasing the performance of the intake system. The components of the intake system include, but are not limited to, the intake manifold of the internal combustion engine, valves of the internal combustion engine, the compressor wheel  40  of the turbocharger  10 , the compressor housing interior  44  of the compressor housing  42 , or an intercooler. 
     More specifically, because the sealing assembly  28  includes the ring  36  disposed between the shaft  12  and the case  30  such that the ring  36  is unobstructed by the case  30  radially between the shaft  12  and the ring  36 , the sealing assembly  28  is thermally stable at the high temperatures (e.g. about 300 degrees centigrade) present during operation of the turbocharger  10  such that sealing assembly  28  is prevented from thermally degrading (e.g. melting or oxidizing). The ring  36  being unobstructed by the case  30  radially between the shaft  12  and the ring  36  results in the sealing assembly  28  being able to lift-off close to the shaft  12 , thus removing the need for an o-ring in contact with the shaft  12  that is liable to thermally degrade. 
     Therefore, because the sealing assembly  28  is prevented form thermally degrading, the sealing assembly  28  reduces blowby of the exhaust gas and leakage of the lubricant, thus increasing the life of the sealing assembly  28  and of the turbocharger  10  by maintaining the quality of the lubricant. As such, the sealing assembly improves the durability and reliability of the turbocharger and the internal combustion engine. Moreover, the sealing assembly  28  is able to seal the bearing housing interior  22  and the turbine housing interior  26  without significantly increasing an axial length of the turbocharger  10 . 
     In some embodiments, the case  30  at the first case end  32  has a lip  46  extending radially away from the axis A and directly coupled to the bearing housing  20  to prevent the case  30  from moving axially away from the turbine wheel  18 . The lip  46  may be spaced from the bearing housing  20  along the axis A such that the lip  46  is disposed between the bearing housing  20  and the turbine wheel  18 , as shown in  FIGS.  2 - 6   . Said differently, in this embodiment, the bearing housing  20  is not be disposed axially between the lip  46  and the turbine wheel  18  such that the lip  46  is axially unobstructed by the bearing housing  20  between the lip  46  and the turbine wheel  18 . Alternatively, the bearing housing  20  may define an aperture into which the lip  46  is disposed such that the lip  46  is obstructed by the bearing housing  20  axially between the lip  46  and the turbine wheel  18 . The lip  46  may extend completely about the axis A, or may extend only partially about the axis A. The lip  46  may have multiple sections extending radially away from the axis A that are radially spaced from one another about the axis A. 
     The lip  46  may have a radial surface  48  facing the bearing housing  20  and contactable with the bearing housing  20  to prevent the case  30  from moving axially away from the turbine wheel  18 . The lip  46  may also have an axial surface  50  facing away from the axis A. Although not required, the axial surface  50  may face the bearing housing  20 , may face a heat shield, may face an insert, and/or may face an annular ring. In the embodiments where the axial surface  50  of the lip  46  faces the bearing housing  20 , a space  52  may be defined between the axial surface  50  of the lip  46  and the bearing housing  20 . Although not required, it is also to be appreciated that the lip  46  may be directly coupled to the bearing housing  20  such that the lip  46  is either in direct contact with the bearing housing  20 , or such that the lip  46  is fixed spatially relative to the bearing housing  20 . In a non-limiting example, the lip  46  may be in contact with the insert or the annular ring, which in turn may be fixed spatially relative to the bearing housing  20 . 
     In some embodiments, the deformable component  38  is configured to bias the ring  36  toward the turbine wheel  18 . The deformable component  38  may exert a first force against the second case end  34  of the case  30 , and the first force may be exerted away from the turbine wheel  18 . However, in the embodiments where the first force is exerted against the second case end  34  of the case  30  and the case  30  has the lip  46 , the lip  46  of the case  30  prevents the second case end  34  of the case  30  from moving axially away from the turbine wheel  18 . In these embodiments, therefore, the second case end  34  of the case  30  is static, and the deformable component  38  exerts a second force against the ring  36  to bias the ring  36  toward the turbine wheel  18 . In the embodiments where the deformable component  38  is configured to bias the ring  36  toward the turbine wheel  18 , the deformable component  38  may be a spring. The spring may be, but is not limited to, a conical spring, a wave spring, a coil spring, a compression spring, and/or a disc or Belleville spring. 
     Moreover, it is also to be appreciated that the case  30  and the bearing housing  20  may be interference fit with one another, and the lip  46  of the case  30  may also be interference fit with the bearing housing  20 . In the embodiments where the case  30  is interference fit with the bearing housing  20 , the case  30  and lip  46  may be rotationally and axially fixed relative to the bearing housing  20  and may be sealed relative to bearing housing  20 . 
     In some embodiments, as shown in  FIGS.  2 ,  3 , and  6   , the second case end  34  of the case  30  extends radially inward toward the shaft  12 . The second case end  34  of the case  30  may extend radially inward toward the shaft  12  and present a coupling surface  54  to which the deformable component  38  may couple. In the embodiments where the deformable component  38  is configured to bias the ring  36  toward the turbine wheel  18 , the first force may be exerted against the second case end  34  of the case  30  that extends radially inward toward the shaft  12 . The second case end  34  of the case  30  may also assist in limiting the exhaust gas from contacting the deformable component  38 , thus acting as a shield against the exhaust gas and extending the life, durability, and reliability of the deformable component  38 . More specifically, any exhaust gas that leaks into the bearing housing interior  22  may be limited in contacting the deformable component  38  by the second case end  34  of the case  30  partially surrounding the deformable component  38 . In the embodiments where the second case end  34  of the case  30  extends radially inward toward the shaft  12 , the case  30  in cross-section is generally L-shaped or generally Z-shaped. 
     Alternatively, as shown in  FIGS.  4  and  5   , the second case end  34  of the case  30  may extend axially away from the turbine wheel  18 . In these embodiments, the case  30  may still have the coupling surface  54  to which the deformable component  38  may couple. The coupling surface  54  may extend radially away from the axis A and face away from the turbine wheel  18 , as shown in  FIGS.  4  and  5   . Alternatively, the coupling surface  54  may extend axially along the axis A, and either may face the shaft  12  or may face away from the shaft  12 . 
     In some embodiments, the deformable component  38  is disposed between the shaft  12  and the case  30  such that the deformable component  38  is unobstructed by the case  30  radially between the shaft  12  and the deformable component  38 . In this embodiment, the case  30  is open or semi-open. In the embodiments where the second case end  34  of the case  30  extends axially away from the turbine wheel  18  and the deformable component  38  is disposed between the shaft  12  and the case  30  such that the deformable component  38  is unobstructed by the case  30  radially between the shaft  12  and the deformable component  38 , the case is open. In other words, in these embodiments, the deformable component  38  is enclosed by the case  30  on one of four sides in cross-section when open. In the embodiments where the second case end  34  of the case  30  extends radially inward toward the shaft  12  and the deformable component  38  is disposed between the shaft  12  and the case  30  such that the deformable component  38  is unobstructed by the case  30  radially between the shaft  12  and the deformable component  38 , the case  30  is semi-open. In other words, in these embodiments, the deformable component  38  is enclosed by the case  30  on two of four sides in cross-section when semi-open. 
     Similarly, in the embodiments where the second case end  34  of the case  30  extends axially away from the turbine wheel  18  and the ring  36  is disposed between the shaft  12  and the case  30  such that the ring  36  is unobstructed by the case  30  radially between the shaft  12  and the ring  36 , the case is open. In other words, in these embodiments, the ring  36  is enclosed by the case  30  on one of four sides in cross-section when open. In the embodiments where the second case end  34  of the case  30  extends radially inward toward the shaft  12  and the ring  36  is disposed between the shaft  12  and the case  30  such that the ring  36  is unobstructed by the case  30  radially between the shaft  12  and the ring  36 , the case  30  is semi-open. In other words, in these embodiments, the ring  36  is enclosed by the case  30  on two of four sides in cross-section when semi-open. 
     It is to be appreciated that the case  30  may be both semi-open and obstruct the deformable component  38  radially between the shaft  12  and the deformable component  38  without obstructing the ring  36  radially between the shaft  12  and the ring  36 . 
     To further limit blowby of the exhaust gas and leakage of the lubricant, the shaft  12  may define a seating groove  56 , and the sealing assembly  28  may further include a piston ring  36  disposed between the case  30  and the shaft  12 , and at least partially in the seating groove  56  defined by the shaft  12 . The shaft  12  may also define a second seating groove, a third seating groove, or more than three seating grooves into which a second piston ring, a third piston ring, or more than three piston rings may be at least partially disposed in. The piston ring  58  forms a labyrinth seal by defining a tortuous flow path. 
     It is to be appreciated that the shaft  12  may define the seating groove  56  without having the piston ring  58  being disposed at least partially in the seating groove  56 , while still disrupting conduction of heat from the high temperature turbine housing interior  26  through the shaft  12  to the bearing housing interior  22 , and also to the lubricant. In the embodiments where the shaft  12  defines the seating groove  56  without having the piston ring  58  being disposed at least partially in the seating groove  56 , the seating groove  56  may function as a heat choke to reduce heat flow to the sealing assembly  28 . 
     Although not required, the turbocharger  10  also typically includes a bearing  60  disposed about the shaft  12  for supporting rotation of the shaft  12 . The bearing  60  may be, but is not limited to, a journal bearing, a ball bearing, a roller bearing, a semi-floating bushing, or a fully-floating bushing. 
     In some embodiments, as shown in  FIGS.  4 - 6   , the sealing assembly  28  further includes a spacer  62  extending along the axis A, disposed between the deformable component  38  and the shaft  12 , and disposed between the ring  36  and the shaft  12 . The spacer  62  may also be disposed at least partially between the bearing  60  and the shaft  12 . The spacer  62  may prevent contact between the bearing  60  and the sealing assembly  28 , thus preventing potential damage to the sealing assembly  28  caused by the contact with the bearing  60  while the bearing  60  is rotating about the axis A. The spacer  62  may comprise a material with low thermal conductivity to limit heat transfer from the shaft  12  to the bearing  60 , the bearing housing interior  22 , the case  30 , the ring  36 , and the deformable component  38 . Preferably, the spacer  62  may comprise titanium because of the low thermal conductivity of titanium. It is to be appreciated, however, that the spacer  62  may comprise other materials, including, but not limited to, aluminum, steel, iron, lead, copper, brass, bronze, and/or plastics and polymeric materials. 
     The sealing assembly  28  may further include a sealing member  64  disposed between the ring  36  and the case  30  such that the ring  36  is disposed between the sealing member  64  and the shaft  12 . The sealing member  64  may be an o-ring, a gasket, a lip seal, a flip seal, a quad ring, an x-ring, a tubular ring, a c-ring, packing, and/or any elastomeric or metal material that my form a fluid-tight barrier between the ring  36  and the case  30  while being moveable with the ring  36  to seal the bearing housing interior  22  and the turbine housing interior  26 . It is also to be appreciated that the sealing assembly  28  may include two or more sealing members  64  disposed between the ring  36  and the case  30 . Although not limiting, the sealing member  64  may comprise perfluoroelastomers, fluorocarbons, and/or silicones. The arrangement of components in the sealing assembly  28  prevents the sealing assembly from reaching temperatures high enough to cause failure of the sealing member  64 . 
     The ring  36  may present a first sealing surface  66  facing the turbine wheel  18 . The first sealing surface  66  may be flat. In one embodiment, as shown in  FIG.  2   , the sealing assembly may further include an isolator  68  coupled to the shaft  12 , and the isolator  68  may present a second sealing surface  70  contactable with the first sealing surface  66  of the ring  36  to seal the bearing housing interior  22  and the turbine housing interior  26 . It is to be appreciated that the isolator  68  may be relatively thin in cross-section to limit transfer of heat from the shaft  12  to the isolator  68 . It is also to be appreciated that the second sealing surface  70  may be flat. 
     Because the ring  36  is moveable with the deformable component  38 , the first sealing surface  66  of the ring  36  may contact the second sealing surface  70  of the isolator  68 . More specifically, before operation of the turbocharger  10 , the first sealing surface  66  of the ring  36  is in contact with the second sealing surface  70  of the isolator  68 . During operation of the turbocharger  10 , a film pressure is generated between the first sealing surface  66  of the ring  36  and the second sealing surface  70  of the isolator  68 . 
     The film pressure pushes against the first sealing surface  66  of the ring  36 , and thus against the deformable component  38 , to move the first sealing surface  66  of the ring  36  away from the second sealing surface  70  of the isolator  68  to form a gap therebetween. Said differently, during operation of the turbocharger  10 , the ring  36  may lift off the isolator  68 . The film pressure present in the gap is a barrier against blowby of the exhaust gas and leakage of the lubricant, and thus maintains sealing while reducing power friction losses. The film pressure generated in the gap between the first sealing surface  66  of the ring  36  and the second sealing surface  70  of the isolator  68  generally makes the sealing assembly  28  a non-contacting face seal, as referred to in the art. 
     The isolator  68  and the shaft  12  may together define an insulating cavity  72  therebetween to further seal the bearing housing interior  22  and the turbine housing interior  26 . The insulating cavity  72  disrupts conduction of heat from the high temperature turbine housing interior  26  through the shaft  12  to the bearing housing interior  22 , and thus also to the lubricant. The isolator  68  and the insulating cavity  72  may also both prevent the temperature of the sealing member  64  from increasing to the point of failure of the sealing member  64 . More specifically, the isolator  68  and the insulating cavity  72  may prevent the sealing member  64  from being fixed in compression, due to thermal degradation and/or loss of elasticity, during thermal soak back of the high temperatures (e.g. about 400 degrees centigrade) present and stored in the turbine housing interior  26  after operation of the turbocharger  10  and the internal combustion engine. 
     The isolator  68  may comprise a material with low thermal conductivity to limit heat transfer from the shaft  12  to the bearing  60 , the bearing housing interior  22 , the case  30 , the ring  36 , and the deformable component  38 . Preferably, the isolator  68  may comprise titanium because of the exceptionally low thermal conductivity of titanium. It is to be appreciated, however, that the isolator  68  may comprise other materials, including, but not limited to, aluminum, steel, iron, lead, copper, brass, bronze, and/or plastics and polymeric materials. 
     The isolator  68  in cross-section may be generally L-shaped or generally Z-shaped. The isolator  68  may also be fixedly coupled to the shaft  12 . Although not required, the isolator  68  may be laser welded to, resistance welded to, spot welded to, brazed to, soldered to, mechanically affixed to, press fit with, and/or cast integrally with the shaft  12  to be fixedly coupled to the shaft  12 . The isolator  68 , thus, may be rotationally coupled with the shaft  12  such that the isolator  68  rotates with the shaft  12 . The isolator  68  may also define pressure-generating grooves for generating the film pressure between the first sealing surface  66  of the ring  36  and the second sealing surface  70  of the isolator  68  when the shaft  12  is rotating. Particularly, the pressure-generating grooves may be spiraled. 
     In another embodiment, as shown in  FIGS.  3 - 6   , the shaft  12  presents a third sealing surface  74  contactable with the first sealing surface  66  of the ring  36  to seal the bearing housing interior  22  and the turbine housing interior  26 . It is to be appreciated that the third sealing surface  74  may be flat. Because the ring  36  is moveable with the deformable component  38 , the first sealing surface  66  of the ring  36  may contact the third sealing surface  74  of the shaft  12 . More specifically, before operation of the turbocharger  10 , the first sealing surface  66  of the ring  36  is in contact with the third sealing surface  74  of the shaft  12 . During operation of the turbocharger  10 , the film pressure is generated between the first sealing surface  66  of the ring  36  and the third sealing surface  74  of the shaft  12 . The film pressure pushes against the first sealing surface  66  of the ring  36 , and thus against the deformable component  38 , to move the first sealing surface  66  of the ring  36  away from the third sealing surface  74  of the shaft  12  to form a gap therebetween. Said differently, during operation of the turbocharger  10 , the ring  36  may lift off the shaft  12 . The film pressure present in the gap is a barrier against blowby of the exhaust gas and leakage of the lubricant, and thus maintains sealing while reducing power friction losses. The film pressure generated in the gap between the first sealing surface  66  of the ring  36  and the third sealing surface  74  of the shaft  12  generally makes the sealing assembly  28  a non-contacting face seal. 
     In other embodiments, as shown in  FIGS.  4 - 6   , the deformable component  38  is a bellow  76  having a corrugated configuration. The bellow  76  may expand and contract with the movement of the ring  36 . It is to be appreciated that the bellow  76  may also be configured to bias the ring  36  toward the turbine wheel  18 . The bellow  76  may exert a first force against the second case end  34  of the case  30 , and the first force may be exerted away from the turbine wheel  18 . However, in the embodiments where the first force is exerted against the second case end  34  of the case  30  and the case  30  has the lip  46 , the lip  46  of the case  30  may prevent the second case end  34  of the case  30  from moving axially away from the turbine wheel  18 . In these embodiments, therefore, the second case end  34  of the case  30  is static, and the bellow  76  may exert a second force against the ring  36  to bias the ring  36  toward the turbine wheel  18 . 
     In some embodiments, as shown in  FIG.  6   , the second case end  34  of the case  30  extends radially inward toward the shaft  12 . In the embodiments where the bellow  76  is configured to bias the ring  36  toward the turbine wheel  18 , the first force is exerted against the second case end  34  of the case  30  that extends radially inward toward the shaft  12 . The second case end  34  of the case  30  may also assist in limiting the exhaust gas from contacting the bellow  76 , thus acting as a shield against the exhaust gas and extending the life, durability, and reliability of the bellow  76 . More specifically, any exhaust gas that leaks into the bearing housing interior  22  may be limited in contacting the deformable component  38  by the second case end  34  of the case  30  partially surrounding the deformable component  38 . 
     The bellow  76  may have a first bellow end  78  extending radially away from the shaft  12  and fixedly coupled to the second case end  34  of the case  30 . Although not required, the first bellow end  78  of the bellow  76  may be laser welded to, resistance welded to, spot welded to, brazed to, soldered to, mechanically affixed to, press fit with, and/or cast integrally with the second case end  34  of the case  30  to be fixedly coupled to the second case end  34  of the case  30 . 
     The bellow  76  also has a second bellow end  80  opposite the first bellow end  78 . It is to be appreciated that the first and second bellow ends  78 ,  80  need not be the exact terminuses of the bellow  76 . The second bellow end  80  of the bellow  76  may be fixedly coupled to the ring  36  to allow the bellow  76  to be moveable with the ring  36 . In some embodiments, as shown in  FIGS.  4 - 6   , the second bellow end  80  of the bellow  76  is encompassed by the ring  36 . The ring  36  may comprise carbon, silicon nitride, ceramics, aluminum, steel, iron, lead, copper, brass, bronze, and/or plastics and polymeric materials. Although not limiting, the ring  36  may be molded onto the second bellow end  80  of the bellow  76 , or the ring  36  may be sintered onto the second bellow end  80  of the bellow  76 . 
     In some embodiments, the second bellow end  80  of the bellow  76  extends along the axis A toward the turbine wheel  18 . In this embodiment, as shown in  FIGS.  4  and  6   , the second bellow end  80  of the bellow  76  may be encompassed by the ring  36  such that only a portion of the bellow  76  that extends along the axis A is encompassed by the ring  36 . It is to be appreciated that the second bellow end  80  need not be the exact terminus of the bellow  76 . 
     Alternatively, in other embodiments, the second bellow end  80  extends either radially inward toward the shaft  12 , as shown in  FIG.  5   , or radially outward away from the shaft  12 . In the embodiments where the second bellow end  80  of the bellow  76  is encompassed by the ring  36 , the second bellow end  80  of the bellow  76  may be angled relative to where the bellow  76  begins to be encompassed by the ring  36 . Angling the second bellow end  80  of the bellow  76  relative to where the bellow  76  begins to be encompassed by the ring  36  increases the strength at which the bellow  76  is coupled to the ring  36 . In other words, angling the second bellow end  80  of the bellow  76  relative to where the bellow  76  begins to be encompassed by the ring  36  prevents the second bellow end  80  of the bellow  76  from being removed (e.g. pulled out) from the ring  36  during operation of the turbocharger  10  or when the ring  36  moves with the bellow  76 . 
     The second bellow end  80  may define at least one of a plurality of holes  82 , grooves  84 , and notches  86 , encompassed by the ring  36 , as shown in  FIGS.  7 - 9 B . The plurality of holes  82 , plurality of grooves  84 , and/or plurality of notches  86  that may be defined by the ring  36  increase the strength at which the bellow  76  is coupled to the ring  36 . In other words, the plurality of holes  82 , plurality of grooves  84 , and/or plurality of notches  86  that may be defined by the second bellow end  80  further prevents the second bellow end  80  of the bellow  76  from being removed (e.g. pulled out) from the ring  36  during operation of the turbocharger  10 , or when the ring  36  moves with the bellow  76 . It is to be appreciated that the plurality of grooves  84  may be defined on an outer surface of the second bellow end  80 , as shown in  FIG.  9 A , may be defined on an inner surface of the second bellow end  80 , as shown in  FIG.  9 B , or may be defined on both the inner and outer surfaces of the second bellow end  80 . 
     Moreover, the second bellow end  80  may be shaped to have a plurality of corrugations  88  and/or a plurality of protrusions  90 , encompassed by the ring  36 , as shown in  FIGS.  10  and  11   , respectively. The plurality of corrugations  88  and/or the plurality of protrusions  90  that may be shaped with the second bellow end  80  increase the strength at which the bellow  76  is coupled to the ring  36 . In other words, the plurality of corrugations  88  and/or the plurality of protrusions  90  that may be shaped with the second bellow end  80  further prevents the second bellow end  80  of the bellow  76  from being removed (e.g. pulled out) from the ring  36  during operation of the turbocharger  10 , or when the ring  36  moves with the bellow  76 . 
     It is to be appreciated that either the case  30 , the ring  36 , or both the case  30  and the ring  36  may include an anti-rotation feature to prevent rotation of either the case  30 , the ring  36 , or both the case  30  and the ring  36  relative to the bearing housing  20 . 
     The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings, and the invention may be practiced otherwise than as specifically described.