Patent Publication Number: US-10323690-B2

Title: Vertical bearing device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a U.S. National Stage Patent Application from International Patent Application No. PCT/JP2016/072378, filed on Jul. 29, 2016, which is based on and claims priority to Japanese Patent Application No. 2015-162026, filed on Aug. 19, 2015, the entire contents of both of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a vertical bearing device. 
     BACKGROUND OF THE INVENTION 
     A vertical bearing device that supports a rotating shaft member of a rotary machine such as a large generator and electric motor is publicly known. The vertical bearing device supports both of thrust load in the axial direction and radial load in the radial direction, of the rotating shaft member that extends vertically in the direction of gravitational force. Bearing parts corresponding to axial and radial load of the vertical bearing device become heated by rotation of the rotating shaft member, and therefore need to be appropriately cooled. Conventionally, a vertical bearing device has been adopting an air cooler that cools the whole device mainly by air-blowing, or an oil cooler that cools lubricating oil on the outside. When an air cooler is used, a fan that rotates with the rotating shaft member is used to cool the bearing device by an air flow generated by the fan (Japanese Patent Laid-Open No, 2003-293977). Instead, when an oil cooler is used, a pump device or the like for circulating lubricating oil is used to discharge lubricating oil that lubricates the bearing part to the outside, for example, and the lubricating oil is circulated between the bearing device and the cooler to thereby cool the bearing device (Japanese Patent Laid-Open No. 5-106636). 
     However, since rotary machines to which the vertical bearing device is applied are becoming larger and high-speed, the heat generated at the bearing parts also tends to increase. For this reason, the vertical bearing device is required to have higher cooling capacity. However, when an air cooler such as that described in Japanese Patent Laid-Open No. 2003-293977 is used, cooling capacity depends on air flow and the contact area between the air flow and radiator fins that come into contact therewith. In other words, to enhance cooling capacity, it is essential to enlarge the surface area of the radiator fins. Accordingly, improvement in cooling capacity causes a problem of enlargement of radiator fins, and therefore enlargement of the vertical bearing device itself. 
     When an oil cooler is used, enlargement of the vertical bearing device itself can be avoided, but piping from the vertical beating device to the external oil cooler is required. This complicates structure and maintenance. Moreover, if a failure occurs in the function of the oil cooler or the piping, it becomes difficult to cool the vertical bearing device itself. 
     SUMMARY OF THE INVENTION 
     Hence, an objective of the present invention is to provide a vertical bearing device that has high cooling capacity, while preventing enlargement and complication of structure and maintenance. 
     In a vertical beating device, a container-shaped casing partitions an oil chamber into an upper oil chamber on the upper side and a lower oil chamber on the lower side in the direction of gravitational force, the oil chamber being formed by the casing and a base plate. A cooling part has a lubricating oil passage part that allows passage of lubricating oil moving from the upper oil chamber to the lower oil chamber. Lubricating oil stored in the upper oil chamber moves to the lower oil chamber in the direction of gravitational force, through the lubricating oil passage part of the cooling part. The cooling part is exposed to the outside from the casing. Hence, lubricating oil flowing through the cooling part loses heat in the cooling part exposed to the outside of the casing. Thus, lubricating oil having absorbed heat of a thrust bearing part and a journal bearing part is cooled in the cooling part while moving from the upper oil chamber to the lower oil chamber. As a result, the circulating lubricating oil prompts cooling of the heated thrust bearing part and journal bearing part. Additionally, the cooling part is provided integrally with the casing, on the radially outer side of the casing. For this reason, the cooling part does not require long piping. In this way, cooling capacity can be improved while preventing complication of structure and maintenance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a section of a vertical bearing device of a first embodiment. 
         FIG. 2  is a diagram of a rotary machine to the vertical bearing device of the first embodiment is applied. 
         FIG. 3  is an arrow view as seen from an arrow III direction of  FIG. 1 . 
         FIG. 4  is an enlarged view enlarging the vicinity of an annular part of the vertical bearing device of  FIG. 1 . 
         FIG. 5  is a cross-sectional view of the annular part illustrated in  FIG. 4 , cut along line V-V of  FIG. 4 . 
         FIG. 6  is an enlarged view enlarging the vicinity of a connection hole of the vertical bearing device illustrated in  FIG. 4 . 
         FIG. 7  is a cross-sectional view of a casing of the vertical bearing device of the first embodiment, cut along line VII-VII of  FIG. 4 . 
         FIG. 8  is a cross-sectional view of the vicinity of the connection hole of  FIG. 7 , cut along line of  FIG. 7 . 
         FIG. 9  is an enlarged view further enlarging the vicinity of the annular part of the vertical bearing device illustrated in  FIG. 4 . 
         FIG. 10  is a cross-sectional view of the vicinity of a connection hole of a modification of the first embodiment, cut along a position corresponding to line VIII-VIII of  FIG. 7 . 
         FIG. 11  is a cross-sectional view of the vicinity of the connection hole of the modification of the first embodiment, cut along the position corresponding to line VIII-VIII of  FIG. 7 . 
         FIG. 12  is a cross-sectional view of a part of a casing and a cooling part of a vertical bearing device of a second embodiment. 
         FIG. 13  is a cross-sectional view of a part of a casing and a cooling part of a vertical bearing device of a modification of the second embodiment. 
         FIG. 14  is a cross-sectional view of a part of a casing and a cooling part of a vertical bearing device of a modification of the second embodiment. 
         FIG. 15  is a cross-sectional view of a part of a casing and a cooling part of a vertical bearing device of a modification of the second embodiment. 
         FIG. 16  is a schematic diagram of a section of a vertical bearing device of a third embodiment. 
         FIG. 17  is a schematic diagram of a section of a vertical bearing device of a modification of the third embodiment. 
         FIG. 18  is a schematic diagram of a section of a vertical bearing device of a fourth embodiment. 
         FIG. 19  is a schematic diagram of a section of a vertical bearing device of a fifth embodiment. 
         FIG. 20  is a cross-sectional view of a part of a casing and a cooling part of a vertical bearing device of a sixth embodiment. 
         FIG. 21  is a cross-sectional view of a part of a casing and a cooling part of a vertical bearing device of another embodiment. 
     
    
    
     BRIEF DESCRIPTION OF EMBODIMENT(S) OF THE INVENTION 
     Hereinafter, vertical bearing devices of multiple embodiments will be described on the basis of the drawings. Note that in the multiple embodiments, substantially common parts are assigned the same reference numerals, and descriptions thereof will be omitted. 
     First Embodiment 
     A vertical bearing device  10  illustrated in  FIGS. 1, 2, and 3  is used as a bearing of a rotary machine  11  illustrated in  FIG. 2 . The rotary machine  11  includes a rotor  13  that rotates around a rotating shaft member  12 , such as a generator, pump, motor, and a turbine. The rotary machine  11  is not limited to these examples, and may be applied to any device that rotates around a rotating shaft member  12 . The rotary machine  11  includes the rotating shaft member  12  at the center of rotation. The rotating shaft member  12  extends vertically in the direction of gravitational force. The vertical bearing device  10  supports the rotating shaft member  12  of the rotary machine  11  at the upper end of the rotary machine  11 , that is, on the upper side in the direction of gravitational force. The vertical bearing device  10  is fixed on a floor  14  of a facility, and suspends and supports the rotary machine  11 . Note that the rotating shaft member  12  may penetrate the vertical bearing device  10  in the upper direction, and a drive source that drives the rotating shaft member  12  may be provided above the vertical bearing device  10 . 
     As illustrated in  FIG. 1 , the vertical bearing device  10  includes a thrust collar  21 , a base plate  22 , a thrust bearing portion  23 , a casing  24 , a journal bearing portion  25 , and a cooling portion  26 . The thrust collar  21  is formed into a cylinder, and is provided integrally with the rotating shaft member  12 . Accordingly, the thrust collar  21  rotates integrally with the rotating shaft member  12 . The thrust collar  21  has an upper face portion  31 , a cylinder portion  32 , and an annular portion  33 . The upper face portion  31 , cylinder portion  32 , and annular portion  33  are formed as one body. The upper face portion  31  is positioned at the upper end of the thrust collar  21 , and the rotating shaft member  12  penetrates the center of the upper face portion  31 . The cylinder portion  32  extends downward from the upper face portion  31 , and is provided on the axially outer side of the rotating shaft member  12  as a cylinder that is concentric with the rotating shaft member  12 . The annular portion  33  is provided at the lower end of the cylinder portion  32 , that is, on an end part opposite to the upper face portion  31 . The annular portion  33  has a larger outer diameter than the cylinder portion  32 , and its end part on the outer peripheral side protrudes farther to the radially outer side than the cylinder portion  32 . The annular portion  33  has, in the radial direction of the rotating shaft member  12 , an inner peripheral face  331  on the inner peripheral side and an outer peripheral face  332  on the outer peripheral side. The rotating shaft member  12  is assembled integrally with the thrust collar  21  by penetrating the upper face portion  31  of the thrust collar  21 . The rotating shaft member  12  is fixed to the thrust collar  1  by press-fitting or welding, for example. 
     The base plate  22  has a main body  34  and an oil cylinder portion  35 . The main body  34  and the oil cylinder portion  35  of the base plate  22  are formed as individual members, or are formed as one body by a single member. In the embodiment, the oil cylinder portion  35  is formed separately from the main body  34 , and is attached to the main body  34 . The main body  34  is formed into a circular plate having an opening  36  at the center thereof. The rotating shaft member  12  penetrates the center opening  36 . The oil cylinder portion  35  is provided as a cylinder formed along the edge of the opening  36  of the main body  34 , and extends upward from the main body  34 . Hence, the oil cylinder portion  35  cylindrically surrounds the radially outer side of the rotating shaft member  12 . The base plate  22  is fixed to the floor  14  of the facility, or is fixed to an unillustrated housing or the like of the rotary machine  11 . 
     The thrust bearing portion  23  is provided in a part where the thrust collar  21  and the base plate  22  face each other. Specifically, the thrust bearing portion  23  is provided in a part where the thrust collar  21  and the base plate  22  face each other in the axial direction of the rotating shaft member  12 . In the embodiment, the thrust bearing portion  23  is provided in the main body  34  of the base plate  22 , in a position where it faces the annular portion  33  of the thrust collar  21 . The thrust bearing portion  23  slides on the annular portion  33  of the thrust collar  21  that rotates together with the rotating shaft member  12 . To be specific, the thrust bearing portion  23  slides on a sliding surface  333  on the main body  34  side of the annular portion  33 . Thus, the thrust hearing portion  23  axially supports the rotation of the rotating shaft member  12 . 
     The casing  24  surrounds the outer peripheral side of the rotating shaft member  12 . The casing  24  has a casing main body  41 , a middle wall  42 , an inner wall  43 , and a lower wall  44 . The casing  24  is connected to the base plate  22  on the lower end thereof. The casing  24  forms, together with the base plate  22 , a container having an open upper end. The container-like space formed of the casing  24  and the base plate  22  is an oil chamber  45  that stores lubricating oil. In other words, the casing  24  is integrated with the base plate  22  to form a container, and forms the oil chamber  45 . The lubricating oil is filled in the oil chamber  45   
     The casing main body  41  is formed into an annular shape, and constitutes an outer wall of the casing  24 . The lower end of the casing main body  41  is in contact with the base plate  22 . The middle wall  42  is provided in the middle of the casing main body  41  in the axial direction, and protrudes radially inward from the casing main body  41 . That is, the middle wall  42  protrudes to the rotating shaft member  12  side in an annual shape, from an inner wall of the casing main body  41 . The inner wall  43  extends upward from the vicinity of a radially inner end part of the middle wall  42 . The inner wall  43  is provided in a cylindrical shape in the vicinity of the radially inner end part of the middle wall  42 . The lower wall  44  extends downward from the middle of the middle wall  42  in the radial direction. As in the case of the inner wall  43 , the lower wall  44  is provided in a cylindrical shape below the middle wall  42 . 
     Thus, the middle wall  42  of the casing  24  partitions the oil chamber  45  formed with the base plate  22  into an upper oil chamber  46  and a lower oil chamber  47 . The upper oil chamber  46  is formed into an annular shape between the casing main body  41  and the inner wall  43 , on the upper side of the middle wall  42 . Meanwhile, the lower oil chamber  47  is formed into an annular or cylindrical shape between the casing main body  41  and the lower wall  44 , on the lower side of the middle wall  42 . As described above, the casing  24  uses the middle wall  42  to partition the oil chamber  45  into the upper oil chamber  46  on the upper side and the lower oil chamber  47  on the lower side in the direction of gravitational force. The casing  24  has a top plate  48 . The top plate  48  covers the upper end side of the container-shaped oil chamber  45 . 
     The journal bearing portion  25  is provided in a part where the thrust collar  21  and the casing  24  face each other. Specifically, the journal bearing portion  25  is provided in a part where the thrust collar  21  and the casing  24  face each other in the radial direction of the rotating shaft member  12 . In the embodiment, the journal bearing portion  25  is provided on the inner wall  43  of the casing  24 , in a position where it faces the cylinder portion  32  of the thrust collar  21 . The journal bearing portion  25  slides on the cylinder portion  32  of the thrust collar  1  that rotates together with the rotating shaft member  12 . To be specific, the journal bearing portion  25  slides on an outer peripheral face of the cylinder portion  32 . Thus, the journal bearing portion  25  radially supports the rotation of the rotating shaft member  12 . 
     The cooling portion  26  has a lubricating oil passage portion  51  and a radiating portion  52 . The lubricating oil passage portion  51  is configured of a pipe-like member that allows passage of lubricating oil, and has a lubricating oil groove formed therein. The lubricating oil passage portion  51  has one end connected to the upper oil chamber  46 , and the other end connected to the lower oil chamber  47 . Specifically, the lubricating oil passage portion  51  has an upper end part connected to the upper oil chamber  46 , and a lower end part connected to the lower oil chamber  47 . The lubricating oil passage portion  51  is directly attached to the casing main body  41 . In other words, the lubricating oil passage portion  51  is formed integrally with the casing main body  41 . Moreover, the lubricating oil passage portion  51  protrudes radially outward from the casing main body  41 . That is, the lubricating oil passage portion  51  is exposed to the outside from the casing main body  41 . The radiating portion  52  is provided in the lubricating oil passage portion  51  exposed from the casing main body  41 . The radiating portion  52  has unillustrated radiator fins and other parts to ensure surface area for heat exchange. As illustrated in  FIG. 3 , multiple cooling portions  26  are provided in the circumferential direction of the vertical bearing device  10 . In the embodiment, the vertical bearing device  10  includes four cooling portions  26  equally spaced apart in the circumferential direction. The number and arrangement of the cooling portions  26  are not limited to the example illustrated in  FIG. 3 , and may be set arbitrarily. 
     Lubricating oil stored in the upper oil chamber  46  illustrated in  FIG. 1  flows to the lower oil chamber  47  on the lower side through the lubricating oil passage portion  51 , due to gravity and a pumping effect caused by circulation of the lubricating oil. At this time, lubricating oil passes through the lubricating oil passage portion  51  exposed from the casing main body  41 . Hence, lubrication oil loses heat in the radiating portion  52  disposed in the way of lubricating oil passage portion  51 . That is, lubricating oil loses heat in the radiating portion  52  while flowing from the upper oil chamber  46  to the lower oil chamber  47  through the lubricating oil passage portion  51 , and is cooled. As has been described, the cooling portion  26  cools lubricating oil flowing from the upper oil chamber  46  to the lower oil chamber  47 . 
     In addition to the above, the vertical bearing device  10  also includes an air blowing portion  53 . The air blowing portion  53  has a fan portion  54  that rotates together with the rotating shaft member  12 . Rotation of the fan portion  54  together with the rotating shaft member  12  forms an up-to-down air flow on the outer side of the casing  24 . The air flow moves along the top plate  48  and the casing main body  41  of the casing  24 , and passes the radiating portion  52  of the cooling portion  26 . Thus, the air flow formed by rotation of the fan portion  54  cools the casing  24  and the cooling portion  26 . Consequently, heat loss from lubricating oil stored in the oil chamber  45  and lubricating oil passing through the cooling portion  26  is prompted. The casing  24  may have fins  49  in a position where the air flow is formed by rotation of the fan portion  54 . 
     The casing  24  partitions the oil chamber  45  not only into the upper oil chamber  46  and the lower oil chamber  47 , but also into a circulation oil chamber  55 . The circulation oil chamber  55  is formed in a part of the oil chamber  45  except for the upper oil chamber  46  and the lower oil chamber  47 . The circulation oil chamber  55  accommodates a part of the cylinder portion  32  and the annular portion  33  of the thrust collar  21 . Additionally, the thrust bearing portion  23  and the journal bearing portion  25  are provided in the circulation oil chamber  55 . That is, the thrust bearing portion  23  that slides on the annular portion  33  of the thrust collar is positioned on the lower side of the circulation oil chamber  55 . Meanwhile, the journal bearing portion  25  that slides on the cylinder portion  32  of the thrust collar  21  is positioned on the upper side of the circulation oil chamber  55 . 
     The circulation oil chamber  55  includes an inner peripheral passage  56 , an outer peripheral passage  57 , a thrust chamber  58 , and a journal chamber  59 . The inner peripheral passage  56  is formed between the inner peripheral face  331  of the annular portion  33  and the oil cylinder portion  35  of the base plate  22 . The outer peripheral passage  57  is formed between the outer peripheral face  332  of the annular portion  33  and the middle wall  42  and lower wall  44  of the casing  24 . The inner peripheral passage  56  and the outer peripheral passage  57  are formed into an annular shape continuous in the circumferential direction of the rotating shaft member  12 . The thrust chamber  58  is formed between the lower end of the annular portion  33  and the base plate  22 . The thrust chamber  58  accommodates the thrust bearing portion  23 . The journal chamber  59  is formed between the cylinder portion  32  of the thrust collar  21  and the inner wall  43  of the casing  24 . The journal chamber  59  accommodates the journal bearing portion  25 . 
     The lubricating oil having moved from the upper oil chamber  46  to the lower oil chamber  47  through the cooling portion  26  flows into the circulation oil chamber  55 , through a lower oil groove  61  formed in the base plate  22 . The lower oil groove  61  is formed as a radially extending groove or an annular recess on the upper side, that is, on the casing  24  side, of the base plate  22 . Lubricating oil in the lower oil chamber  47  passes through the lower oil groove  61  to move to the inner peripheral passage  56  of the circulation oil chamber  55 . 
     The lubricating oil having flowed into the circulation oil chamber  55  is returned to the upper oil chamber  46 , by use of rotation of the thrust collar  21  inside the circulation oil chamber  55 . Thus, the lubricating oil stored in the upper oil chamber  46  is circulated through the cooling portion  26 , lower oil chamber  47 , lower oil groove  61 , and circulation oil chamber  55 . Details of the system for circulating lubricating oil will be described later. Heat generated by sliding of the thrust bearing portion  23  and the journal bearing portion  25  is absorbed by the circulating lubricating oil, Then, the absorbed heat is passed through the cooling portion  26  by circulation of the lubricating oil, and is thereby dissipated in the cooling portion  26 . As a result, the lubricating oil is cooled, and cooling of the thrust bearing portion  23  and journal bearing portion  25  where frictional heat is generated is prompted. 
     Next, the system for circulating lubricating oil from the circulation oil chamber  55  to the upper oil chamber  46  will be described in detail. 
     As illustrated in  FIG. 4 , the vertical bearing device  10  includes a circulation system part  70 . The circulation system part  70  has a circulation hole  71 . The circulation hole  71  is provided in the annular portion  33  of the thrust collar  21 , and penetrates the annular portion  33  from inner to outer sides in the radial direction, As illustrated in  FIG. 5 , multiple circulation holes  71  are extend radially in the circumferential direction of the annular portion  33 . In the embodiment, the annular portion  33  has  12  circulation holes  71  extending radially in the circumferential direction. One end of the circulation hole  71  opens on the outer peripheral face  332 . of the annular portion  33 , and the other end opens on the inner peripheral face  331  of the annular portion  33 . Additionally, as illustrated in  FIG. 4 , the circulation hole  71  is tilted upward from the inner peripheral face  331  toward the outer peripheral face  332  in the radial direction of the rotating shaft member  12 . In other words, of the circulation hole  71 , the end on the outer peripheral face  332  side is positioned higher than the end on the inner peripheral face  331  side in the axial direction of the rotating shaft member  12 , Note that the circulation hole  71  may be tilted with respect to the radial direction of the annular portion  33 . Each of or each group of the circulation hole  71  may have the same or different widths and/or orientations. Note, however, that in the context of manufacturing, it is preferable that the circulation holes  71  all have the same width and orientation. As described above, the width and orientation of the circulation holes  71  can be set arbitrarily to control movement of lubricating oil, depending on the required performance of the vertical bearing device  10 . 
     Since the circulation holes  71  are provided in the annular portion  33 , when the thrust collar  21  rotates together with the rotating shaft member  12 , lubricating oil on the inner peripheral side of the annular portion  33  in the circulation oil chamber  55  is guided to the outer peripheral side of the annular portion  33  by the circulation holes  71 . That is, since the thrust collar  21  rotates relative to the fixed base plate  22 , the lubricating oil on the inner peripheral side of the annular portion  33  flows toward the upper oil chamber  46  through the circulation holes  71 . Thus, a flow of lubricating oil from the circulation oil chamber  55  toward the upper oil chamber  46  is formed. At this time, the upward inclination of the circulation holes  71  allows the lubricating oil to be guided more smoothly toward the upper oil chamber  46  on the upper side. Since the lubricating oil in the circulation oil chamber  55  flows into the upper oil chamber  46  through the circulation holes  71 , the lubricating oil in the lower oil chamber  47  is supplied to the circulation oil chamber  55  through the lower oil groove  61 . The lower oil groove  61  connects the lower oil chamber  47  and the inner peripheral passage  56  of the circulation oil chamber  55 . That is, the lubricating oil stored in the lower oil chamber  47  is supplied to the inner peripheral passage  56  from the lower oil chamber  47 , through the lower oil groove  61 . 
     As described above, the outer peripheral passage  57  is formed between the outer peripheral face  332  of the annular portion  33  of the thrust collar  21  and the middle wall  42  and lower wall  44  of the casing  24 . The distance between the outer peripheral face  332  and the casing  24  in the outer peripheral passage  57 , is preferably set larger on the upper part than in the lower part in the axial direction of the rotating shaft member  12 . To give a specific description, the lower end of the circulation hole  71  provided in the annular portion  33  is extended to set a virtual line L. As illustrated in  FIG. 6 , when the lower end of the circulation hole  71  is extended, the virtual line L intersects with the casing  24 . With this, the outer peripheral passage  57  is formed by being surrounded with faces  571  and  572  which are inner walls of the casing  24 , and faces  573  and  574  which constitute the outer peripheral face  332  of the annular portion  33 . In the outer peripheral passage  57 , the distance between the faces  572 . and  574  facing each other above the virtual line L is set larger than the distance between the faces  571  and  573  facing each other below the virtual line L. To be more specific, the outer peripheral passage  57  surrounded by the middle wall  42  and lower wall  44  of the casing  24  and the annular portion  33  bulges toward the outer peripheral side, above an intersection point P where the outer peripheral passage  57  intersects with the virtual line L. Thus, in the outer peripheral passage  57 , the distance between opposing faces increases above the virtual line L. In addition, the casing  24  may have a curved face portion  72  on a wall face extending upward from the intersection point P. In other words, an end part on the inner peripheral side of the middle wall  42  and lower wall  44  of the casing  24  may have the curved face portion  72  curving upward from the intersection point P. Note that the outer peripheral passage  57  may be formed such that the distance between the casing  24  and the outer peripheral face  332  increases continuously from lower to upper sides, in a section including the center axis of the rotating shaft member  12 . 
     The casing  24  has a connection hole  73  in the middle wall  42  that separates the circulation oil chamber  55  and the upper oil chamber  46 . In other words, the connection hole  73  connects the circulation oil chamber  55  and the upper oil chamber  46  by penetrating the middle wall  42 . The connection hole  73  has a radially outer face  731  and a radially inner face  732 . The connection hole  73  has a lower opening  74  and an upper opening  75 . The lower opening  74  is a lower end of the connection hole  73 , and opens to the outer peripheral passage  57  of the circulation oil chamber  55 . The upper opening  75  is an upper end of the connection hole  73 , and opens to the upper oil chamber  46 . As illustrated in  FIGS. 7 and 8 , in the connection hole  73 , it is preferable that the opening area of the lower opening  74  be smaller than the opening area of the upper opening  75 . It is also preferable that the connection hole  73  be formed into a. tapered shape where the sectional area increases continuously from the lower opening  74  toward the upper opening  75 . 
     Multiple connection holes  73  are provided in the circumferential direction of the casing  24 . In the embodiment, the casing  24  has six connection holes  73  in the circumferential direction. The number of connection holes  73  may be set arbitrarily. As illustrated in  FIGS. 6 and 7 , for example, in the middle wall  42  in which the connection hole  73  is formed, it is preferable that the face  732  on the inner peripheral side in the radial direction of the rotating shaft member  12  extend parallel to the axis of the rotating shaft member  12 . That is, in the embodiment, the connection hole  73  is formed such that the inner peripheral face  732  is parallel to the center axis of the rotating shaft member  12 . Meanwhile, in the middle wall  42  in which the connection hole  73  is formed, the outer peripheral face  731  in the radial direction of the rotating shaft member  12  is tilted relative to the center axis of the rotating shaft member  12  That is, in the connection hole  73 , the outer peripheral face  731  is tilted in such a manner as to draw away from the rotating shaft member  12  toward the upper side. Hence, the connection hole  73  is formed into a tapered shape where the sectional area increases continuously from the circulation oil chamber  55  side, toward the upper oil chamber  46 . 
     As illustrated in FIGS,  4  and  9 , the vertical bearing device  10  includes a journal through hole  76 . The journal through hole  76  penetrates the cylinder portion  32  of the thrust collar  21  in the radial direction. The journal through hole  76  connects the inner peripheral passage  56  of the circulation oil chamber  55  and the journal chamber  59 , by penetrating the cylinder portion  32 . Hence, lubricating oil in the inner peripheral passage  56  of the circulation oil chamber  55  flows into the journal chamber  59  through the journal through hole  76 . The lubricating oil having flowed into the journal chamber  59  is circulated into the upper oil chamber  46  from the journal chamber  59 , by rotation of the thrust collar  21 . At this time, the lubricating oil having flowed into the journal chamber  59  lubricates the journal bearing portion  25 , and flows into the upper oil chamber  46 . The journal through hole  76  may or may not be tilted from the inner peripheral side to the outer peripheral side, in radial and axial directions of the rotating shaft member  12 . Additionally, each of or each group of the journal through hole  76  may have the same or different widths and/or orientations. Note, however, that in the context of manufacturing, it is preferable that the journal through holes  76  all have the same width and orientation. As described above, the width and orientation of the journal through holes  76  can be set arbitrarily to control movement of lubricating oil, depending on the required performance of the vertical bearing device  10 . 
     The vertical bearing device  10  includes a seal member  77 . The seal member  77  is provided in a position where the upper end of the annular portion  33  of the thrust collar  21  and the lower end of the middle wall  42  of the casing  24  face each other, As mentioned earlier, the circulation oil chamber  55  includes the thrust chamber  58  that accommodates the thrust bearing portion  23 , and the journal chamber  59  that accommodates the journal bearing portion  25 . The lubricating oil supplied to the circulation oil chamber  55  from the lower oil chamber  47  through the lower oil groove  61 , is circulated to the upper oil chamber  46  through the following three circulation paths in the circulation oil chamber  55 . 
     Path 1: circulation path starting from the inner peripheral passage  56 , lubricating the thrust bearing portion  23  of the theist chamber  58 , and flowing toward the upper oil chamber  46  through the outer peripheral passage  57  and the connection hole  73   
     Path 2: circulation path starting from the inner peripheral passage  56 , and flowing toward the upper oil chamber  46  through the circulation hole  71  of the annular portion  33 , the outer peripheral passage  57 , and the connection hole  73   
     Path 3: circulation path starting from the inner peripheral passage  56 , lubricating the journal bearing portion  25  of the journal chamber  59  after passing through the journal through hole  76 , and flowing toward the upper oil chamber  46   
     As described above, lubricating oil in the circulation oil chamber  55  flows into the upper oil chamber  46  through three paths. At this time, the lubricating oil having flowed into the journal chamber  59  through Path 3 may pass through between the upper end of the annular portion  33  and the lower end of the middle wall  42  and form a flow into the outer peripheral passage  57 , instead of lubricating the journal bearing portion  25  accommodated in the journal chamber  59 . For this reason, the seal member  77  is provided between the upper end of the annular portion  33  and the lower end of the middle wall  42 . Thus, the flow of lubricating oil in Path 3 from the journal through hole  76  directed toward the outer peripheral passage  57  is restricted by the seal member  77 . Conversely, the seal member  77  also restricts the lubricating oil flowing through the outer peripheral passage  57  after passing through Path 1 or 2 from flowing into the journal chamber  59 . Lubricating oil having passed through Path 1 and cooled the thrust bearing portion  23  of the thrust chamber  58  also flows through the outer peripheral passage  57 . The lubricating oil having passed through Path 1 is heated after cooling the thrust bearing portion  23 . If the heated lubricating oil flows into the journal chamber  59 , it may hinder cooling of the journal bearing portion  25  accommodated in the journal chamber  59  by lubricating oil. Hence, the seal member  77  is provided to restrict the flow of lubricating oil from the outer peripheral passage  57  into the journal chamber  59  as well. 
     The upper end of the annular portion  33  and the lower end of the middle wall  42  are also parts where the fixed casing  24  and the rotating thrust collar  21  face each other in the axial direction of the rotating shaft member  12 . Accordingly, the seal member  77  may be a secondary thrust bearing portion that supports the thrust collar  21  in the axial direction, together with the thrust beating portion  23 . That is, the seal member  77  supports the rotating shaft member  12  in the axial direction, together with the thrust bearing portion  23 . 
     As illustrated in  FIGS. 4 and 9 , the thrust collar  21  may have introduction portions  78  and  79 . The introduction portion  78  is provided in the inner peripheral face  331  of the annular portion  33  of the thrust collar  21 . Meanwhile, the introduction portion  79  is provided on an inner peripheral face of the cylinder portion  32  of the thrust collar  21 . Ends of the circulation hole  71  and the journal through hole  76  open on the inner peripheral face of the thrust collar  21 . The introduction portion  78  is provided at the inner peripheral opening of the circulation hole  71 . Similarly, the introduction portion  79  is provided at the inner peripheral opening of the journal through hole  76 . The introduction portion  78  is recessed radially outward from the inner peripheral face  331 . In addition, the introduction portion  78  is formed such that its inner diameter gradually decreases from the inner peripheral face  331  toward the opening of the circulation hole  71 . Similarly, the introduction portion  79  is recessed radially outward from the inner peripheral face of the cylinder portion  32 . The introduction portion  79 , too, is formed such that its inner diameter gradually decreases from the inner peripheral face of the cylinder portion  32  toward the opening of the journal through hole  76 . The introduction portions  78  and  79  are provided in the circulation hole  71  and the journal through hole  76  that open on the inner peripheral face of the thrust collar  21 , respectively. Note that the introduction portions  78  and  79  may be formed into a circumferentially continuous groove on the inner peripheral face of the thrust collar  21 . In this case, each of the introduction portions  78  and  79  is formed such that its inner diameter in the axial direction of the rotating shaft member  12  gradually decreases toward the opening of the circulation hole  71  or the journal through hole  76 . The groove-like part as the introduction portions  78  and  79  may be formed into an annular shape continuous in the circumferential direction of the thrust collar  21 , or may be discontinuous in the circumferential direction. Moreover, the circumferential depth and axial width of the groove-like parts serving as the introduction portions  78  and  79  may be changed arbitrarily in different positions. The introduction portion  78  guides lubricating oil in the inner peripheral passage  56  into the circulation hole  71 . Similarly, the introduction portion  79  guides lubricating oil in the inner peripheral passage  56  into the journal through hole  76 . This prompts the lubricating oil in the inner peripheral passage  56  to flow into the circulation hole  71  and the journal through hole  76 . Note that the embodiment illustrates an example in which both of the introduction portions  78  and  79  are formed. However, the configuration may include one or both of the introduction portions  78  and  79 . 
     A description will be given of circulation of lubricating oil and cooling of the thrust bearing portion  23  and the journal bearing portion  25  by lubricating oil, according to the vertical bearing device  10  configured in the above manner. 
     The thrust collar  21  rotates together with the rotating shaft member  12 . Accordingly, the thrust collar  21  rotates inside the fixed base plate  22  and casing  24 . Lubricating oil stored in the circulation oil chamber  55  forms a flow directed from inner to outer sides of the rotating shaft member  12 , that is, from the inner peripheral passage  56  to the outer peripheral passage  57 , due to centrifugal force and shear force caused by rotation of the thrust collar  21 , or differential pressure caused by difference in flow rate, for example. This flow causes the lubricating oil in the inner peripheral passage  56  to circulate to the upper oil chamber  46  through the thrust chamber  58  as in the aforementioned Path 1, through the circulation hole  71  as in the aforementioned. Path 2, and through the journal chamber  59  as in the aforementioned Path 3. 
     The circulation hole  71  constituting Path 2 penetrates the annular portion  33  of the thrust col lar  21 , and therefore lubricating oil receives relatively low resistance through the path. Meanwhile, the thrust chamber  58  constituting Path 1 accommodates the thrust bearing portion  23 . Hence, the flow rate of lubricating oil passing through the circulation hole  71  becomes higher than the flow rate of lubricating oil passing through the thrust chamber  58 . The lubricating oil having passed the circulation hole  71  and having a high flow rate flows out to the outer peripheral passage  57 , and its flow direction is smoothly directed upward along the curved face portion  72  formed in the casing  24 . Thus, lubricating oil having flowed into the outer peripheral passage  57  from the circulation hole  71  changes its flow direction upward along the curved face portion  72 , and flows into the connection hole  73 , At this time, the flow rate of lubricating oil from the circulation hole  71  toward the connection hole  73  is higher than the flow rate of lubricating oil from the thrust chamber  58  to the outer peripheral passage  57 . The difference in flow rate between lubricating oil flowing through different paths causes the lubricating oil flowing from the thrust chamber  58  to the outer peripheral passage  57  to be absorbed into lubricating oil directed from the circulation hole  71  toward the connection hole  73 . As a result, the lubricating oil passing through the thrust chamber  58  of Path 1 having a high resistance is drawn up into the upper oil chamber  46  through the connection hole  73 , by the flow of lubricating oil passing through the circulation hole  71  of Path 2. Hence, the lubricating oil having cooled the thrust bearing portion  23  in the thrust chamber  58  does not accumulate in the thrust chamber  58  and the outer peripheral passage  57 , but is circulated to the upper oil chamber  46 . 
     Additionally, rotation of the thrust collar  21  circulates a part of lubricating oil in the inner peripheral passage  56  to the upper oil chamber  46 , through the journal through hole  76  and the journal chamber  59  constituting Path 3. In this case, too, the lubricating oil in the inner peripheral passage  56  flows into the journal chamber  59  through the journal through hole  76 , due to centrifugal force and shear force caused by rotation of the thrust collar  21 , or differential pressure caused by difference in flow rate, for example. The lubricating oil having flowed into the journal chamber  59  is caused to flow into the upper oil chamber  46  from the journal chamber  59 , after lubricating oil is continuously supplied to the journal chamber  59  by rotation of the thrust collar  21 . Hence, the lubricating oil having cooled the journal bearing portion  25  in the journal chamber  59  does not accumulate in the journal chamber  59 , but is circulated to the upper oil chamber  46 . 
     The lubricating oil having returned to the upper oil chamber  46  by circulation flows down to the lower oil chamber  47 , due to gravity and a pumping effect caused by circulation of the lubricating oil. At this time, since the upper oil chamber  46  is connected to the cooling portion  26 , lubricating oil in the upper oil chamber  46  flows into the lower oil chamber  47  through the cooling portion  26 . Although the upper oil chamber  46  is connected to the outer peripheral passage  57  of the circulation oil chamber  55  through the connection hole  73 , lubricating oil passing through Paths 1 and 2 flow into the upper oil chamber  46  through the connection hole  73 , as described earlier. Hence, it is assumed that no flow of lubricating oil from the upper oil chamber  46  toward the circulation oil chamber  55  through the connection hole  73  will occur. 
     The lubricating oil having flowed into the cooling portion  26  loses heat by passing through the radiating portion  52 . Specifically, the lubricating oil having absorbed the heat generated from sliding of the thrust bearing portion  23  and the journal bearing portion  25  loses heat by passing through the cooling portion  26 . The cooled lubricating oil flows into the lower oil chamber  47 . When the thrust collar  21  rotates, lubricating oil in the circulation oil chamber  55  flows out toward the upper oil chamber  46 , as mentioned earlier. Hence, when the lubricating oil in the circulation oil chamber  55  decreases, the lubricating oil having flowed into the lower oil chamber  47  is supplied to the inner peripheral passage  56  of the circulation oil chamber  55  through the lower oil groove  61 . 
     As has been described, the thrust collar  21  rotating together with the rotating shaft member  12  forms a flow of lubricating oil passing through the circulation oil chamber  55  and a flow of lubricating oil passing through the cooling portion  26 , between the upper oil chamber  46  and the lower oil chamber  47 . In other words, a flow of lubricating oil circulating between the upper oil chamber  46  and the lower oil chamber  47  is formed. As a result, the lubricating oil repeats cooling of the thrust bearing portion  23  and journal bearing portion  25 , and the heat dissipation in the cooling portion  26 . This enables lubrication and cooling of the thrust bearing portion  23  and journal bearing portion  25  of the vertical bearing device  10 , and heat dissipation of lubricating oil having absorbed heat from the cooling. 
     In the aforementioned first embodiment, the lubricating oil passage portion  51  constituting the cooling portion  26  is exposed to the outside. Hence, the lubricating oil flowing through the lubricating oil passage portion  51  loses heat in the radiating portion  52  in the lubricating oil passage portion  51  exposed to the outside of the casing  24 . Thus, the lubricating oil having absorbed heat of the thrust bearing portion  23  and the journal bearing portion  25  is cooled in the cooling portion  26  while moving from the upper oil chamber  46  to the lower oil chamber  47 . As a result, the circulating lubricating oil prompts cooling of the heated thrust bearing portion  23  and journal bearing portion  25 . Additionally, the lubricating oil passage portion  51  of the cooling portion  26  is provided integrally with the casing  24 , on the radially outer side of the casing  24 . For this reason, the cooling portion  26  does not require long piping. Hence, cooling capacity can be enhanced without complicating structure and maintenance. 
     Moreover, the first embodiment includes the air blowing portion  53 . The air blowing portion  53  forms a flow of air toward the cooling portion  26 , by the fan portion  54  that rotates together with the rotating shaft member  12 . Accordingly, cooling of the cooling portion  26  is prompted by the flow of air formed by the fan portion  54 . Hence, it is possible to prompt heat dissipation of lubricating oil circulating through the cooling portion  26 , and to prompt cooling of the thrust bearing portion  23  and journal bearing portion  25  by lubricating oil. 
     In the first embodiment, the thrust bearing portion  23  and the journal bearing portion  25  are provided in the circulation oil chamber  55 , through which the lubricating oil circulating from the lower oil chamber  47  to the upper oil chamber  46  flows. Hence, the thrust bearing portion  23  and the journal bearing portion  25  that generate heat from supporting rotation of the rotating shaft member  12  are cooled by the lubricating oil flowing through the circulation oil chamber  55 . Accordingly, it is possible to prompt cooling of the thrust bearing portion  23  and journal bearing portion  25 , and suppress seizing. Hence, an anti-seize property of the vertical bearing device  10  can be improved. 
     Additionally, the first embodiment includes the circulation system part  70 . In the circulation system part  70 , multiple circulation holes  71  are formed in the annular portion  33  of the thrust collar  21 . When the annular portion  33  of the thrust collar  21  rotates together with the rotating shaft member  12 , centrifugal force and shear force, or differential pressure caused by difference in flow rate, for example, are generated in the lubricating oil in the circulation oil chamber  55 . With this, the lubricating oil in the circulation oil chamber  55  is guided from inner to outer sides of the annular portion  33 , through the circulation holes  71  penetrating the annular portion  33 . The flow of lubricating oil guided by the circulation holes  71  forms a flow of lubricating oil directed toward the upper oil chamber  46 , from the lower oil chamber  47  through the circulation oil chamber  55 . As a result, the lubricating oil stored in the lower oil chamber  47  is circulated to the upper oil chamber  46  through the circulation oil chamber  55 , by rotation of the thrust collar  21 . Accordingly, it is possible to prompt circulation of lubricating oil without using a pump device or the like. Then, the thrust bearing portion  23  and journal bearing portion  25  are lubricated and cooled by the circulating flow of lubricating oil. Hence, seizing of the thrust bearing portion  23  and journal bearing portion  25  can be suppressed. 
     In the first embodiment, the circulation hole  71  is tilted upward from inner to outer sides. Hence, the flow of lubricating oil passing through the circulation hole  71  is directed upward, that is, toward the upper oil chamber  46 , when the lubricating oil flows out of the circulation hole  71 . This allows the lubricating oil having passed the circulation hole  71  to be easily guided to the upper oil chamber  46 . Accordingly, it is possible to prompt the flow of lubricating oil having passed the circulation hole  71 , and to thereby prompt circulation of the lubricating oil. Additionally, the circulation hole  71  penetrates the annular portion  33  of the thrust collar  21 . The thrust bearing portion  23  is provided on the lower end of the annular portion  33 . Since lubricating oil flows through the circulation hole  71 , the thrust bearing portion  23  is cooled by the lubricating oil flowing through the circulation hole  71 . Hence, it is also possible to prompt cooling of the thrust bearing portion  23  and thrust collar  21 . 
     In the first embodiment, in the outer peripheral passage  57 , the distance between the faces  572  and  574  above the virtual line L is set larger than the distance between the faces  571  and  573  below the virtual line L. The flow rate of lubricating oil passing through the circulation hole  71  is higher than the flow rate of lubricating oil passing through the thrust bearing portion  23 . Hence, the flow of lubricating oil passing through the circulation hole  71  and flowing toward the upper oil chamber  46  draws up the lubricating oil passing through the thrust bearing portion  23 . As a result, on the upper side of the virtual line L, lubricating oil having passed through the thrust bearing portion  23  flows together with lubricating oil having passed through the circulation hole  71  For this reason, the distance is increased on the upper side of the virtual line so that the lubricating oil having an increased flow rate does not accumulate and flows toward the upper oil chamber  46 . Hence, it is possible to prompt circulation of lubricating oil. 
     In the first embodiment, the casing  24  has the curved face portion  72  on a wall face provided higher than the intersection point P with the virtual line L. Lubricating oil having flowed out of the circulation hole  71  is guided smoothly by the curved face portion  72 , to the upper oil chamber  46  on the upper side. Accordingly, resistance in the circulation path of lubricating oil is reduced, and circulation of the lubricating oil can be prompted. 
     In the first embodiment, the connection hole  73  provided in the middle wall  42  of the casing  24  connects the circulation oil chamber  55  and the upper oil chamber  46 . The connection hole  73  is formed into a tapered shape whose sectional area increases continuously toward the upper oil chamber  46 , from the outer peripheral passage  57  side of the circulation oil chamber  55 . Hence, the lubricating oil on the circulation oil chamber  55  side is guided by the connection hole  73  having the increasing sectional area, and is moved to the upper oil chamber  46 . Accordingly, it is possible to prompt circulation of lubricating oil without increasing resistance. 
     In the first embodiment, the inner peripheral face  732  of the connection hole  73  is parallel to the center axis of the rotating shaft member  12 . Accordingly, a flow directed toward the upper oil chamber  46  on the upper side is formed in the lubricating oil passing through the connection hole  73 , and therefore the flow is less likely to be disturbed. Hence, it is possible to suppress increase in resistance due to flow disturbance, and to prompt circulation of lubricating oil. 
     The first embodiment includes the seal member  77 , The seal member  77  restricts the flow of lubricating oil between the outer peripheral passage  57  and the journal chamber  59 . If lubricating oil flows from the journal chamber  59  to the outer peripheral passage  57 , lubrication of the journal bearing portion  25  accommodated in the journal chamber  59  may become insufficient. On the other hand, if lubricating oil flows from the outer peripheral passage  57  to the journal chamber  59 , the lubricating oil heated from cooling the thrust bearing portion  23  may flow into the journal bearing portion  25  and raise the temperature of the journal bearing portion  25 . Hence, by providing the seal member  77 , the flow of lubricating oil between the outer peripheral passage  57  and the journal chamber  59  can be blocked. It is therefore possible to prompt circulation of lubricating oil without hindering lubrication and cooling of the journal beating portion  25 . 
     In the first embodiment, the seal member  77  may serve as a secondary thrust bearing portion. In this configuration, the rotating shaft member  12  is supported by the seal member  77  serving as the thrust bearing portion  23  and the secondary thrust bearing portion. Hence, it is possible to more stably support the rotating shaft member  12  and prompt circulation of lubricating oil, without increasing the number of parts. 
     The first embodiment includes the introduction portion  78  to the inlet of the circulation hole  71 , and the introduction portion  79  to the inlet of the journal through hole  76 . The introduction portions  78  and  79  are set such that their inner diameter decrease toward the circulation hole  71  and the journal through hole  76 . With this, the introduction portions  78  and  79  guide lubricating oil in the inner peripheral passage  56  to the circulation hole  71  and the journal through hole  76 . In other words, the lubricating oil in the inner peripheral passage  56  is guided by these introduction portions  78  and  79  to be introduced into the circulation hole  71  and journal through hole  76 . This prompts the flow of lubricating oil from the inner peripheral passage  56  to the circulation hole  71  and the journal through hole  76 . Hence, it is possible to prompt circulation of lubrication oil. 
     Modification of First Embodiment 
     In the aforementioned first embodiment, in the connection hole  73 , tilted faces tilt in opposite directions relative to the circumferential direction of the casing  24 , so as to be symmetric to each other, as illustrated in  FIGS. 7 and 8 . However, the connection hole  73  may be configured such that the tilted faces tilt in the same direction relative to the circumferential direction, as illustrated in  FIG. 10 . If the rotating shaft member  12  is configured to rotate both in the normal and reverse directions, it is preferable that the connection hole  73  be formed into the shape illustrated in  FIGS. 7 and 8 . Additionally, the front and rear inclinations of the connection hole  73  in the circumferential direction of the casing  24  may be the same as illustrated in  FIGS. 8 and 10 , or may be different as illustrated in  FIG. 11 . In both cases, the shape of the connection hole  73  can be set arbitrarily to control movement of lubricating oil, depending on the required performance of the vertical bearing device  10 . 
     Second Embodiment 
       FIG. 12  illustrates a vertical bearing device of a second embodiment. 
       FIG. 12  is a cross-sectional view in which a casing  24  is cut in an intermediate part thereof in the axial direction, and from which a middle wall  42 , an inner wall  43 , and other parts are omitted. In the second embodiment, a casing main body  41  constituting an outer wall of the casing  24  has a plane portion  81  extending flat in the circumferential direction. That is, the casing main body  41  has the plane portion  81  flat in the circumferential direction, and an annular portion  82  that connects the plane portions  81  in the circumferential direction. The annular portion  82  is formed into an annular shape that is concentric with the rotating shaft member  12 . That is, the annular portion  82  is formed into a curved face that is arc shaped in sections such as those illustrated in  FIG. 12 . In the second embodiment, the casing main body  41  has two plane portions  81  and two annular portions  82   
     In the second embodiment, a cooling portion  26  is provided on the plane portion  81  of the casing main body  41 . That is, a lubricating oil passage portion  51  constituting the cooling portion  26  is exposed to the outside of the casing main body  41  from the plane portion  81 , in the casing main body  41 . In addition, a radiating portion  52  constituting the cooling portion  26  is provided in a position facing the plane portion  81 . The two cooling portions  26  of the second embodiment are respectively provided on the two plane portions  81  of the casing main body  41 . 
     By providing the cooling portion  26  on the plane portion  81  as in the second embodiment, an air flow formed by a fan portion  54  flows evenly into a gap between the cooling portion  26  and the plane portion  81 . When the planar cooling portion  26  is provided on the arc-shaped casing main body  41  as in the aforementioned first embodiment, the distance between the cooling portion  26  and the casing main body  41  varies in the circumferential direction of the casing main body  41 . That is, when the arc-shaped casing main body  41  and the planar cooling portion  26  face each other, the distance between the casing main body  41  and the cooling portion  26  is larger on both end sides in the circumferential direction of the casing main body  41 . On the other hand, the distance between the casing main body  41  and the cooling portion  26  is smaller in a middle part in the circumferential direction of the casing main body  41 . Thus, when the arc-shaped casing main body  41  and the planar cooling portion  26  face each other, the sectional area through which air generated by the fan portion  54  passes through varies in the circumferential direction of the casing main body  41 . Meanwhile, in the second embodiment, the cooling portion  26  and the plane portion  81  are arranged substantially parallel to each other. Hence, the sectional area of the space through which air passes is substantially even in the circumferential direction of the casing main body  41 . With this, the air flow formed by the fan portion  54  passes through the cooling portion  26  evenly. Consequently, cooling efficiency of the cooling portion  26  can be enhanced. 
     Additionally, in the second embodiment, the cooling portion  26  is attached to the planar plane portion  81  in the casing main body  41 . Hence, work for positioning and fixing the cooling portion  26  is made simpler than when providing it on the curved annular portion  82 . As a result, it is possible to improve work efficiency in assembling the cooling portion  26  onto the casing main body  41 . 
     As has been described, in the second embodiment, the plane portion  81  is formed in the casing main body  41 , and the cooling portion  26  is provided on the plane portion  81 . Hence, the flow of cooling air formed by the fan portion  54  passes through the cooling portion  26  evenly, Accordingly, cooling efficiency of the cooling portion  26  is improved, and the cooling portion  26  can be downsized. 
     Moreover, in the second embodiment, the cooling portion  26  is provided on the flat plane portion  81 , so that workability of assembling the cooling portion  26  onto the casing main body  41  can also be improved. 
     Modification of Second Embodiment 
     The second embodiment illustrated in  FIG. 12  describes an example of forming two plane portions  81  in the casing main body  41 , and providing the cooling portions  26  on each of the two plane portions  81 . 
     However, the casing main body  41  may have three plane portions  81  as illustrated in  FIG. 13 . In a vertical bearing device  10  illustrated in  FIG. 13 , a cooling portion  26  may be provided on each of the three plane portions  81 . Instead, a casing main body  41  may have four plane portions  81  as illustrated in  FIG. 14 , or may be configured only of plane portions  81 , as illustrated in  FIG. 15 . 
     Thus, any number of plane portions  81  may be provided in the casing main body  41 . Then, by providing the cooling portion  26  on all or any of the plane portions  81 , more cooling portions  26  can be provided, and cooling efficiency can be improved even more. Additionally, as has been described in the second embodiment, since the cooling portion  26  is provided on the plane portion  81 , attachment of the cooling portion  26  onto the casing main body  41  is made easier. Hence, even when more cooling portions  26  are provided to improve cooling efficiency, attachment of the cooling portion  26  onto the plane portion  81  can drastically reduce man-hours. 
     Third Embodiment 
       FIG. 16  illustrates a vertical bearing device of a third embodiment. 
     In the third embodiment, a radiating portion  52  of a cooling portion  26  is tilted relative to the axial direction of a rotating shaft member  12 . In other words, the radiating portion  52  is not parallel to the rotating shaft member  12 , but is tilted relative thereto. When the radiating portion  52  is provided parallel to the rotating shaft member  12 , that is, provided as in the first embodiment, a flow of air formed by a fan portion  54  passes through between the radiating portion  52  and a casing main body  41  in the axial direction. Then, the flow of cooling air having passed through between the radiating portion  52  and the casing main body  41  is curved radially outward by the base plate  22 . For this reason, the air flow formed by the fan portion  54  is more likely to flow on the lower side of the radiating portion  52  than on the upper side thereof. Accordingly, lubricating oil is cooled mainly on the lower side of the radiating portion  52 , and a radiating surface of the radiating portion  52  cannot be fully used in many cases. 
     Hence, by tilting the radiating portion  52  as in the third embodiment, the air flow formed by the fan portion  54  can be spread more easily over the entire radiating portion  52 . In other words, the air flow formed by the fan portion  54  is more likely to flow into the entire radiating portion  52  than when the radiating portion  52  is parallel to the axis. Hence, it is possible to prompt cooling of lubricating oil without expanding the area of the radiating portion  52 . Accordingly, cooling efficiency of the radiating portion  52  can be improved. 
     Incidentally, the radiating portion  52  may be provided perpendicular to the axial direction of the rotating shaft member  12 , as illustrated in  FIG. 17 . In other words, the radiating portion  52  forms a 90-degree angle with the rotating shaft member  12 . By thus arranging the radiating portion  52  perpendicular to the axis of the rotating shaft member  12 , the air flow formed by the fan portion  54  passes through the entire radiating portion  52  substantially evenly. Hence, it is possible to prompt cooling of lubricating oil without expanding the area of the radiating portion  52 . Accordingly, cooling efficiency of the radiating portion  52  can be improved even more. 
     Fourth Embodiment 
       FIG. 18  illustrates a vertical bearing device of a fourth embodiment. 
     In the fourth embodiment, a cooling portion  26  has a straightening vane  91 . The straightening vane  91  is provided on an inlet side, where air flows into a radiating portion  52  from a fan portion  54 . In the fourth embodiment, the straightening vane  91  is provided in a lubricating oil passage portion  51  connected to an upper oil chamber  46 . Specifically, the straightening vane  91  is provided in a part where the lubricating oil passage portion  51  extending from the upper oil chamber  46  connects to the radiating portion  52 . By providing the straightening vane  91 , an air flow formed by the fan portion  54  is aligned by the straightening vane  91 . That is, the straightening vane  91  cancels disturbance in the air flow formed by the fan portion  54 , and guides a stable air flow to enter the radiating portion  52 . Hence, a less disturbed air flow passes through the radiating portion  52 . 
     In the fourth embodiment, the air flow formed by the fan portion  54  is aligned by the straightening vane  91 , and is guided to the radiating portion  52 . With this, the flow of air passing through the radiating portion  52  is stabilized. Hence, cooling efficiency can be improved. 
     Fifth Embodiment 
       FIG. 19  illustrates a vertical bearing device of a fifth embodiment. 
     A vertical bearing device  10  of the fifth embodiment includes a shielding plate  92 . The shielding plate  92  is provided between a cooling portion  26  and a casing  24 . The shielding plate  92  blocks transmission of heat from the cooling portion  26  to the casing  24 . When the radiating portion  52  is tilted relative to the axis of the rotating shaft member  12  as in the third embodiment illustrated in  FIGS. 16 and 17 , the distance between the radiating portion  52  and the casing  24  is reduced in some parts, When the radiating portion  52  and the casing  24  thus come close, heat may be transmitted from the heated radiating portion  52  to the casing  24 . For this reason, the shielding plate  92  is provided between the radiating portion  52  and the casing  24 , With this, heat of the radiating portion  52  is shielded by the shielding plate  92 , and transmission thereof to the casing  24  can be suppressed. 
     In the fifth embodiment, the shielding plate  92  is provided to suppress transmission of heat from the radiating portion  52  to the casing  24 . Accordingly, it is possible to suppress deterioration in cooling capacity, even when the tilted radiating portion  52  is brought close to the casing  24 . 
     Sixth Embodiment 
       FIG. 20  illustrates a vertical bearing device of a sixth embodiment. 
     In the sixth embodiment, a cooling portion  26  has a lubricating oil passage portion  51 , and multiple radiating portions  52 . The lubricating oil passage portion  51  is exposed to the outside of a casing main body  41  from an upper oil chamber  46 , and consecutively passes through multiple radiating portions  52  before connecting to a lower oil chamber  47 . That is, the lubricating oil passage portion  51  consecutively passes through multiple serially-arranged radiating portions  52 . Hence, lubricating oil having flowed into the lubricating oil passage portion  51  from the upper oil chamber  46  passes through the serial radiating portions  52 , and is thereby cooled in multiple steps. Then, the lubricating oil cooled by the multiple radiating portions  52  flows into the lower oil chamber  47 . 
     In the sixth embodiment, cooling of the lubricating oil flowing through the lubricating oil passage portion  51  is prompted, by allowing the lubricating oil to consecutively pass through multiple radiating portions  52 . Then, in the sixth embodiment, even when multiple radiating portions  52  are provided, only two holes, which are an inlet and an outlet, need to be formed in the casing main body  41  to allow passage of the lubricating oil. For example, when the radiating portion  52  is arranged in front of each of six plane portions  81  provided in the casing main body  41 , six lubricating oil passage portions  51  need to be connected to the casing main body  41 . In this case, two holes for one lubricating oil passage portion  51 , that is, a total of 12 holes need to be formed in the casing main body  41  to allow passage of the lubricating oil. Meanwhile, in the sixth embodiment, even when six radiating portions  52  are provided, only two lubricating oil passage portions  51  are used, and therefore, a total of four holes are formed in the casing main body  41 . Thus, in the sixth embodiment, less holes need to be formed in the casing main body  41  to allow passage of lubricating oil. This reduces man-hours and required parts of the casing main body  41 . Hence, the structure can be simplified while maintaining the cooling capacity. 
     Other Embodiments 
     The present invention described above is not limited to the above embodiments, and is applicable to various embodiments without departing from the gist of the invention. 
     The third embodiment describes a configuration in which the radiating portion  52  is tilted to widen the upper side in the axial direction of the rotating shaft member  12 . However, reversely, the radiating portion  52  may be tilted to widen the lower side in the axial direction of the rotating shaft member  12 . In this case, it is preferable that the shielding plate  92  of the fourth embodiment be provided on the upper side of the radiating portion  52  that comes close to the casing main body  41 . Moreover, the connection between the radiating portion  52  and the lubricating oil passage portion  51  is not limited to the above examples. For example, in the example of  FIG. 17 , the lubricating oil passage portion  51  connects to the radially outer side of the radiating portion  52  from the upper oil chamber  46 , and connects to the lower oil chamber  47  from the radially inner side of the radiating portion  52 . In contrast, the lubricating oil passage portion  51  may connect to the radially inner side of the radiating portion  52  from the upper oil chamber  46 , and connect to the lower oil chamber  47  from the radially outer side of the radiating portion  52 . Additionally, the flow of lubricating oil may be clockwise or anticlockwise, around the rotating shaft member  12 . Thus, connection between the radiating portion  52  and the lubricating oil passage portion  51 , and the direction of flow of lubricating oil may be changed arbitrarily, depending on the usage of the applied radiating portion  52 . 
     In addition, the aforementioned multiple embodiments describe an example in which lubricating oil passing through the radiating portion  52  through the lubricating oil passage portion  51  flows from the upper oil chamber  46  to the lower oil chamber  47 . On the other hand, in another conceivable configuration, lubricating oil passing through the radiating portion  52  through the lubricating oil passage portion  51  may flow from the lower oil chamber  47  to the upper oil chamber  46 . In this case, lubricating oil passing through the radiating portion  52  flows from the lower oil chamber  47  to the upper oil chamber  46 , by a pumping effect using centrifugal force and shear force generated in the lubricating oil by rotation of the thrust collar  21 . Thus, the path and direction in which lubricating oil flows in the lubricating oil passage portion  51  may be set arbitrarily, as long as the lubricating oil passes through the radiating portion  52 . 
     Moreover, the aforementioned multiple embodiments describe an example in which the plane portion  81  is provided in the casing main body  41  for attachment of the cooling portion  26 . However, as illustrated in  FIG. 21 , the cooling portion  26  does not necessarily have to be attached on the plane portion  81  of the casing main body  41 . That is, the casing main body  41  may have a plane portion  81  that does not have the cooling portion  26  attached thereon.