Bearing cooling apparatus of heating roller

A bearing cooling apparatus of a heating roller wherein the heating roller includes a roller, heating means disposed inside the roller, and a shaft having the roller mounted thereon, comprising a housing having the shaft rotatably supported thereto by bearings attached to the housing and formed with a first passageway and a second passageway, and means for circulating a cooling medium through the first and second passageways. At least one of the first and second passageways extends along the bearing disposed adjacent the heating means and along the shaft and are disposed adjacent the bearing and the shaft.

FIELD OF THE INVENTION 
The present invention relates in general to a bearing cooling apparatus of 
a heating roller and in particular to a bearing cooling apparatus of a 
heating roller which is employed in the heating process of a yarn-like 
material or a sheet-like material such as film or the like. More 
specifically, the present invention relates to a bearing cooling apparatus 
of a heating roller which is employed in the spin draw process of 
thermosetting synthetic fiber or in the spinning process, etc., of 
thermosetting synthetic fiber. 
SUMMARY OF THE INVENTION 
In accordance with one important aspect of the present invention, there is 
provided a bearing cooling apparatus of a heating roller wherein the 
heating roller includes a roller, heating means disposed inside the 
roller, and a shaft having the roller mounted thereon, comprising a 
housing having the shaft rotatably supported thereto by bearings attached 
to the housing and formed with a first passageway and a second passageway, 
at least one of the first and second passageways extending along the 
bearing disposed adjacent the heating means and along the shaft and being 
disposed adjacent the bearing and the shaft, and means for circulating a 
cooling medium through the first and second passageways. 
In accordance with another important aspect of the present invention, there 
is provided a bearing cooling apparatus of a heating roller wherein the 
heating roller includes a roller, heating means disposed inside the 
roller, and a shaft having the roller mounted thereon, comprising a 
housing having the shaft rotatably supported thereto by bearings attached 
to the housing and formed with a first passageway and a second passageway, 
a cooling fin mounted on the shaft between the roller and the bearing 
disposed adjacent the heating means, at least one of the first and second 
passageways extending along the bearing disposed adjacent the heating 
means and along said shaft and along the cooling fin and being disposed 
adjacent the bearing, said shaft and the cooling fin, and means for 
circulating a cooling medium through the first and second passageways. 
In accordance with another important aspect of the present invention, there 
is provided a bearing cooling apparatus of a heating roller wherein the 
heating roller includes a rotatable roller, a heating coil disposed inside 
the rotatable roller, a cylindrical core having the heating coil wound 
therearound, and a rotatable shaft having the rotatable roller mounted 
thereon, comprising a housing having the rotational shaft of the heating 
roller rotatably supported thereto by bearings attached to the housing and 
formed with a first passageway passing therethrough, an annular flange 
having the cylindrical core attached thereto and formed with a second 
passageway passing therethrough, the annular flange being attached to the 
housing, a cooling fin mounted on the rotational shaft between the bearing 
disposed adjacent the heating coil and the rotatable roller, and a 
partition wall extending axially from the annular flange along the 
rotational shaft and along the bearing disposed adjacent the heating coil 
and terminating short of the cooling fin so that a third passageway is 
defined by the housing, the partition wall and the cooling fin and a 
fourth passageway is defined by the cylindrical core, the partition wall 
and the cooling fin, the third passageway being held at one end thereof in 
fluid communication with the first passageway and at the other end thereof 
with one end of the fourth passageway, the other end of the fourth 
passageway being held in fluid communication with the second passageway, 
and means for circulating a cooling medium through the first, second, 
third and fourth passageways. 
In accordance with another important aspect of the present invention, there 
is provided a bearing cooling apparatus of a heating roller wherein the 
heating roller includes a rotatable roller, a heating coil disposed inside 
the rotatable roller, a cylindrical core having the heating coil wound 
therearound, and a rotatable shaft having the rotatable roller mounted 
thereon, comprising a housing having the rotational shaft of the heating 
roller rotatably supported thereto by bearings attached to the housing and 
formed with a first passageway passing therethrough, an annular flange 
having the cylindrical core attached thereto and formed with a second 
passageway passing therethrough, the annular flange being attached to the 
housing, a cooling fin mounted on the rotational shaft between the bearing 
disposed adjacent the heating coil and the roller so that the first 
passageway is held in fluid communication with the second passageway, and 
means for circulating a cooling medium through the first and second 
passageways. 
In accordance with another important aspect of the present invention, there 
is provided a bearing cooling apparatus of a heating roller wherein the 
heating roller includes a rotatable roller, a heating coil disposed inside 
the rotatable roller, a cylindrical core having the heating coil wound 
therearound, and a rotatable shaft having the rotatable roller mounted 
thereon, comprising a housing having the rotational shaft of the heating 
roller rotatably supported thereto by bearings attached to the housing and 
formed with a first passageway, a flange portion of the cylindrical core 
being attached to the housing to define a second passageway therebetween, 
an axial pump mounted on the rotational shaft between the bearing disposed 
adjacent the heating coil and the rotatable roller, and a partition wall 
integrally formed in the housing and axially extending therefrom along the 
bearing disposed adjacent the heating coil and along the rotational shaft 
and terminating short of the axial pump so that a third passageway is 
defined by the housing, the partition wall and the axial pump and a fourth 
passageway is defined by the cylindrical core, the partition wall and the 
axial pump, the third passageway being held at one end thereof in fluid 
communication with the first passageway and at the other end thereof with 
one end of the fourth passageway, the other end of the fourth passageway 
being held in fluid communication with the second passageway, mechanical 
seals disposed between the housing and the axial pump and between the 
cylindrical core and the axial pump to hermetically seal the third 
passageway and the fourth passageway, respectively, and means for 
circulating a cooling medium through the first, second, third and fourth 
passageways. 
In accordance with another important aspect of the present invention, there 
is provided a bearing cooling apparatus of a heating roller wherein the 
heating roller includes a rotatable roller, a heating coil disposed inside 
the rotatable roller, a cylindrical core having the heating coil wound 
therearound, and a rotatable shaft having the rotatable roller mounted 
thereon, comprising a housing having the rotational shaft of the heating 
roller rotatably supported thereto by bearings attached to the housing, 
the cylindrical core attached to the housing and formed with a first 
passageway and a second passageway which are held at one ends thereof in 
fluid communication with each other, a cooling fin mounted on the 
rotational shaft between the bearing disposed adjacent the heating coil 
and the rotatable roller, at least one of the first and second passageways 
extending along the bearing disposed adjacent the heating means and along 
the cooling fin and being disposed adjacent the bearing and the cooling 
fin, and means for circulating a cooling medium through the first and 
second passageways. 
DESCRIPTION OF THE PRIOR ART 
In a conventional heating roller of the type, which is employed in the spin 
draw process and the like of thermosetting synthetic fiber, the heating 
roller is driven by drive means such as, for example, an electric motor. 
In general, the heating roller is mounted directly on a shaft of the 
electric motor, or mounted on a shaft coupled through a coupling member to 
the shaft of the electric motor, in consideration of the resonance point 
and strength of the shaft which are dependent upon operating temperatures, 
thread speeds, denier numbers and the like. Such a heating roller is 
provided with heating means such as, for example, a heater element, an 
induction coil, etc, and in order to rotatably support the shaft of the 
heating roller, a bearing is disposed inside or adjacent the heating 
roller. For this reason, the bearing is heated to a considerably higher 
temperature of the order of 150.degree. C. by heat transferred to the 
bearing through the shaft from the heating means and by radiation of the 
heating means. As a consequence of the high temperature, the bearing is 
damaged and the lubrication oil therefor is degraded. 
Hence, in order to prevent the damage of the bearing and the degradation of 
the lubricating oil, there have been proposed heretofore various kinds of 
bearing cooling apparatuses of the aforementioned heating roller. In the 
conventional bearing cooling apparatuses of these kinds, the bearing is 
cooled by circulating a cooling water therearound through a cooling water 
pipe by means of a circulation system. However, only an outer race of the 
bearing is cooled and the shaft of the heating roller having an inner race 
of the bearing mounted thereon is not cooled. The temperature difference 
therefore becomes large between the inner race and the outer race of the 
bearing. For this reason, the bearing is unduly deformed and damaged due 
to the difference between thermal expansions of the inner and outer races, 
and the lubricating oil is degraded. 
Accordingly, it is the object of the present invention to provide an 
improved bearing cooling apparatus of a heating roller which prevents 
damage of the bearing and degradation of the lubricating oil which are 
caused by the temperature difference between the outer and inner races. 
The object is achieved according to the present by defining a passageway 
for a cooling medium disposed adjacent and extending along the shaft of 
the heating roller and the bearing so that the shaft and the bearing are 
cooled at the same time.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring initially to FIG. 1 of the drawings, a heating roller of a first 
embodiment according to the present invention is designated generally by 
reference numeral 1. The heating roller 1 comprises a rotatable 
cylindrical roller 2, an electromagnetic induction heating coil 4 disposed 
as heating means inside the cylindrical roller 2, a cylindrical core 6 
having the electromagnetic induction heating coil 4 wound therearound, and 
a rotational shaft 8 received at its one end in a central bore formed in a 
boss portion of the roller 2 and attached to the roller 2 by suitable 
fastening means. The rotational shaft 8 extends from the boss portion of 
the cylindrical roller 2 through the cylindrical core 6 and through a 
cylindrical motor housing 10 including a front housing 12, a rear housing 
14 and an end plate 16. The front housing 12, rear housing 14 and end 
plate 16 are connected together in assembled relationship. The rotational 
shaft 8 is rotatably supported at its forward portion by a bearing 18 
attached to an axially extending portion 13 of the front housing 12 and at 
its rearward portion by a bearing 19 attached to the end plate 16. A motor 
generally indicated by reference numeral 20 is disposed as drive means 
inside the motor housing 10 and adapted to drive the heating roller 1 to 
rotate about the rotational shaft 8. The motor 20 comprises a stator 22 
attached to the rear housing 14 and a rotor 24 attached to the rotational 
shaft 8. The bearing 18 attached to the front housing 12 is lubricated by 
a lubrication nozzle 26 arranged adjacent the bearing 18. Likewise, the 
bearing 19 attached to the end plate 16 is lubricated by a lubrication 
nozzle 28 arranged adjacent the bearing 19. 
The front housing 12 of the motor housing 10 further has a radial portion 
15 extending radially outward from the axial portion 13. The radial 
portion 15 is formed with a first inlet passageway 30 passing therethrough 
to take in a cooling medium for cooling the bearing 18 disposed adjacent 
the electromagnetic induction heating coil 4 of the heating roller 1. In 
this embodiment, it will be assumed that the cooling medium is a cooling 
air. The front housing 12 includes an annular flange 32 attached to the 
radial portion 15 of the front housing 12. The annular flange 32 extends 
radially inward from the outer end of the radial portion 15 of the front 
housing 12 and terminates short of the axial portion 13 of the front 
housing 12 as shown. The annular flange 32 is formed with a first outlet 
passageway 34 passing therethrough to discharge the cooling air. A flange 
portion of the aforementioned cylindrical core 6 is attached to the 
annular flange 32 so that an axially extending annular bore 35 is defined 
by the inner peripheral surface of the cylindrical portion of the 
cylindrical core 6, the inner peripheral surface of the annular flange 32, 
the outer peripheral surface of the axial portion 13 of the front housing 
12 and a portion of the rotational shaft 8. 
A cooling fin 36 is mounted on the rotational shaft 8 of the heating roller 
1 adjacent the bearing 18 so that heat to be transferred to the rotational 
shaft 8 from the roller 2 is extracted through the cooling fin 36 by a 
cooling air. The cooling fin 36 has an axial portion with thread-like 
cooling fin portions 36a to induce the flow of a cooling air and increase 
the generating surface thereof, and has a flange portion 36b. The flange 
portion 36b of the cooling fin 36 extends radially outward from the axial 
portion of the cooling fin 36 into the axially extending annular bore 35 
so that the cooling air in the axial annular bore 35 cannot go beyond the 
flange portion 36b. 
A cylindrical partition wall 38 is attached to the annular flange 32 and 
axially extends in the axial annular bore 35 along the rotational shaft 8 
to divide the axial bore 35 into a second inlet passageway 40 defined by 
the inner peripheral surface of the partition wall 38, the outer 
peripheral surface of the axial portion 13 of the front housing 12 and the 
cooling fin 36, and a second outlet passageway 42 defined by the outer 
peripheral surface of the partition wall 38, the inner peripheral surface 
of the cylindrical core 6 and the cooling fin 36. The partition wall 38 
terminates short of the flange portion 36b of the cooling fin 36 so that 
the second inlet passageway 40 is held at one end thereof in communication 
with the second outlet passageway 42. The other end of the second inlet 
passageway 40 communicates with the first inlet passageway 30 formed in 
the radial portion 15 of the front housing 12. Similarly, the second 
outlet passageway 42 communicates with the first outlet passageway 34 
formed in the annular flange 32. The partition wall 38 also serves to 
intercept the flow of radiation of the heating coil 4 directly from the 
inner peripheral surface of the cylindrical core 6 to the cooling fin 36, 
rotational shaft 8 and bearing 18. As shown in FIG. 2, the axial portion 
13 of the front housing 12 is formed with a plurality of equiangularly 
spaced parallel fin portions 44 to increase a generating surface of the 
front housing 12. In this embodiment, although the partition wall 38 is 
not provided with fin portions, it is noted that it may be provided at its 
outer peripheral portion with fin portions to increase the generating 
surface thereof. 
Returning to FIG. 1, a cooling fan 46 is mounted on the rearward portion of 
the rotational shaft 8 extending from the end plate 16 of the motor 
housing 10 in order to take in the cooling air from the outside. In this 
embodiment, althouth the cooling air is taken in, it is noted that a 
cooling air under pressure may be used in place of the cooling fan 46. An 
introduction passageway 48 is defined by a housing cover 50 attached to 
the radial portion 15 of the front housing 12 and by a fan cover 52 
attached to the housing cover 50. The introduction passageway 48 is 
circumferentially divided into a plurality of chambers by a plurality of 
axially extending parallel fin portions provided in the rear housing 14 of 
the motor housing 10. Some of the axial parallel chambers are communicated 
with the first inlet passageway 30 in the front housing 12, while the 
remaining chambers are communicated with a discharge port 54 formed in the 
housing cover 50. A cooling air is drawn in the introduction passageway 48 
by the cooling fan 46 and supplied in part through some of the axial 
parallel chambers to the first inlet passageway 30 and discharged in part 
through the remaining axial chambers from the discharge port 54 after heat 
is extracted from the motor 20 through the fin portions of the rear 
housing 14. Thus, in this embodiment, the fin portions are provided in the 
introduction passageway 48 so that the introduction passageway 48 is 
divided into a plurality of the chambers, thereby increasing the 
generating surface and a cooling effect. 
FIG. 3 illustrates a cooling fin 56 which is one modification of the 
cooling fin 36 shown in FIG. 1. The cooling fin 56 is substantially 
identical in operation and construction to the cooling fin 36 of FIG. 1, 
but characterized in that the axial portion of the cooling fin 56 has 
mounted thereon a plurality of disc-like fin portions 58 each extending 
radially outward. 
FIG. 4 illustrates a cooling fin 60 which is another modification of the 
cooling fin 36 shown in FIG. 1. The cooling fin 56 is substantially 
identical in operation and construction to the cooling fin 36 of FIG. 1, 
but characterized in that the axial portion of the cooling fin 60 has 
mounted thereon a plurality of plate-like fin portions 62 each extending 
at a predetermined angle with respect to the rotational shaft 8. It is 
noted that the plate-like fin portions 62 may extend axially in parallel 
relation with the rotational shaft 8 of the heating roller 1. 
The operation of the aforementioned first embodiment constructed in 
accordance with the present invention will hereinafter be described in 
detail. 
As the heating roller 1 is driven to rotate through the rotational shaft 8 
by the motor 20, the cooling fan 46 rotates together with the rotational 
shaft 8. The rotation of the cooling fan 46 causes the cooling air to be 
drawn inside the fan cover 52 from the outside. The cooling air passes in 
part through some of the chambers in the introduction passageway 48, 
extracting the heat generated in the motor 20 through the fin portions 
formed in the rear housing 14, and is discharged from the discharge port 
54 of the housing cover 50. The cooling air passing through the remaining 
chambers is supplied to the first inlet passageway 30 of the front housing 
12. The cooling air in the first inlet passageway 30 passes through the 
second inlet passageway 40 while extracting the heat transferred to the 
bearing 18 from the outer race of the bearing through the fin portions 44 
of the front housing 12 and at the same time extracting the heat 
transferred to the rotational shaft 8 through the thread-like fin portions 
36a of the cooling fin 36. Thus, since the rotational shaft 8 is also 
cooled by the cooling air, the heat to be transferred to an inner race of 
the bearing 18 through the rotational shaft 8 is considerably reduced. As 
a consequence, the outer and inner races of the bearing 18 are 
simultaneously cooled by the cooling air passing through the second inlet 
passageway 40. The cooling air is then discharged through the second 
outlet passageway 42 and through the first outlet passageway 34. While the 
cooling air is passing through the second outlet passageway 42, the heat 
to be transferred from the inner peripheral surface of the cylindrical 
core 6 directly to the shaft 8 and the bearing 18 is intercepted by the 
partition wall 38 and also the inner peripheral surface of the core 6 is 
always cooled by the cooling air passing through the second outlet 
passageway 42. Therefore, the heat to be transferred directly to the 
bearing 18 is also prevented by the partition wall 38 and the cooling air 
passing through the second outlet passageway 42. 
Thus, in this embodiment of the present invention, the cooling air supplied 
by the cooling fan 46 cools the bearing 18 and the rotational shaft 8 
concurrently while passing through the second inlet and outlet passageways 
40 and 42. As a consequence, the temperature of the bearing 18 falls to 
the order of, for example, 80.degree. C. and the temperature difference 
does not occur between the outer and inner races of the bearing 18. 
Accordingly, the damage of the bearing 18 and the degradation of the 
lubricating oil of the bearing 18 are prevented. Thus, since the desired 
cooling effect is achieved by the simply constructed passageways, the 
whole assembly of the apparatus according to the present invention becomes 
structurally simple, small in size and less expensive. 
Although it has been illustrated and described that the axial portion 13 of 
the front housing 12 is formed with the fin portions 44, it is noted that 
it is not always necessary to provide the fin portions in the second inlet 
passageway 40. Also, although it has been illustrated and described that 
the axial portion of the cooling fin 36 is formed with thread-like fin 
portions 36b, disc-like fin portions 58 or plate-like fin portions 62, it 
is noted that it is not always necessary to provide the fin portions. 
Referring to FIG. 5, there is shown a second embodiment according to the 
present invention. This embodiment is substantially identical in 
construction and operation to the first embodiment described above, except 
that a cooling fan 64 and a fan casing 66 attached to the radial portion 
15 of the front housing 12 are provided to draw a cooling air directly in 
the first inlet passageway 30 formed in the radial portion 15 of the front 
housing 12. The portions substantially identical in operation and 
construction to those of the first embodiment are designated by like 
reference numerals and therefore the description will hereinafter be 
omitted. It is noted that means for drawing a cooling air in the first 
inlet passageway is not limited to the cooling fan 64 of this embodiment 
and that a cooling air under pressure may be supplied to the first inlet 
passageway by fluid compressing means in stead of the cooling fan 64. This 
is applicable to all the embodiments herein described. Also, although the 
cooling fan 64 is provided in the inlet passageway, it is noted that the 
cooling air may be drawn from the outlet passageway by means of fans or 
blowers to pass through the inlet and outlet passageways. 
FIG. 6 depicts a third embodiment constructed in accordance with the 
present invention. The portions substantially identical in operation and 
construction to those of the first embodiment of FIG. 1 are designated by 
like reference numerals. In this embodiment, the portion of a rotational 
shaft 8 extending through a cylindrical core 6 is shortened so that a 
bearing 18 and a cooling fin 36 are disposed outside the cylindrical core 
6. In addition, the partition wall 38 shown in FIG. 1 is not provided in 
the third embodiment. Thus, the cooling air in an inlet passageway 30 
formed in a front housing 12 is discharged through the cooling fin 36 from 
an outlet passageway 34 formed in an annular flange 32 attached to the 
front housing 12. The other constructions and operations are substantially 
identical to those of the first embodiment of FIG. 1 and therefore the 
description will hereinafter be omitted. 
FIG. 7 illustrates a fourth embodiment embodying the present invention. The 
portions substantially identical in operation and construction to those of 
the first embodiment of FIG. 1 are designated by like reference numerals. 
The fourth embodiment of the present invention is characterized in that 
the cooling fin 36 of the first embodiment of FIG. 1 is replaced with a 
boss portion 2a of the roller 2 of the heating roller 1 which is 
integrally formed with a plurality of cooling fin portions 2b. The other 
constructions and operations are substantially identical to the first 
embodiment of FIG. 1 and therefore the description will hereinafter be 
omitted. It should be noted that the cooling fin portions 2b may be of 
disc-like configuration shown in FIG. 3 and of plate-like configuration 
shown in FIG. 4. 
Referring to FIG. 8, there is shown a bearing cooling apparatus of a 
heating roller, which is constructed in accordance with a fifth embodiment 
of the present invention. In the fifth embodiment, it is assumed that a 
cooling medium for cooling a bearing disposed adjacent the heating roller 
is a liquid. The portions substantially identical in operation and 
construction to those of hhe first embodiment of FIG. 1 are indicated by 
like reference numerals. In FIG. 8, a radiator generally designated by 
reference numeral 68 is provided which comprises an inlet nozzle 70 held 
in fluid communication with a first inlet passageway 30 formed in a radial 
portion 15 of a front housing 12, and an outlet nozzle 76 held in fluid 
communication with a first outlet passageway 34 defined by a flange 
portion 80 of a cylindrical core 6 and the radial portion 15 of the front 
housing 12. In this embodiment, the cooling fin 36 of the first embodiment 
shown in FIG. 1 is replaced with an axial pump 84 which is driven by 
rotation of a rotational shaft 8. As the axial pump 84 is driven to 
rotate, the cooling liquid medium in the radiator 68 passes, as indicated 
by an arrow A, from the inlet nozzle 70 through the first inlet passageway 
30 and through a second inlet passageway 40 defined by a partition wall 38 
of the front housing 12, an axial portion 13 of the front housing 12 and 
the axial pump 84, and returns, as indicated by arrows B, through a second 
outlet passageway 42 defined by the partition wall 38, the cylindrical 
portion of the cylindrical core 6 and the axial pump 84. The second inlet 
passageway 40 is sealed by a mechanical seal 86 disposed between the boss 
portion of the axial pump 84 and the axial end of an axial portion 13 of 
the front housing 12 so that the cooling liquid medium in the inlet 
passageway 40 is prevented from leaking in the shaft side. Similarly, the 
second outlet passageway 42 is sealed by a mechanical seal 88 disposed 
between the flange portion of the axial pump 84 and a lug portion 6a 
formed in the cylindrical core 6 so that the cooling liquid medium in the 
outlet passageway 42 is prevented from leaking in the heating coil side. 
The aforementioned radiator 68 is formed with a plurality of radiator fin 
portions 90 to radiate heat while the cooling liquid medium is passing 
through the radiator 68. A cooling air is passed through the radiator fin 
portions 90, as indicated by arrows C, by a cooling fan provided therefor. 
Thus, heat is forcibly radiated from the cooling liquid medium through the 
radiator fin portions 90. The heat can be naturally radiated depending 
upon the outside temperature of the radiator 68 and upon the flow 
condition in the vicinity of the radiator 68. The other constructions and 
operations are substantially identical to the first embodiment of FIG. 1 
and therefore the description will hereinafter be omitted. 
FIG. 9 shows a sixth embodiment of the present invention similar to the 
fifth embodiment of FIG. 8 in that a cooling liquid medium is also 
applicable as a cooling medium to this embodiment. The sixth embodiment is 
characterized in that a core 91 having an electromagnetic induction 
heating coil 4 wound therearound is formed with an inlet passageway 92 and 
an outlet passageway 94 through which the cooling liquid medium circulates 
a radiator 68 and in that the mechanical seals 86 and 88 of the fifth 
embodiment shown in FIG. 8 are omitted. The portions substantially 
identical in construction and operation to those of the fifth embodiment 
of FIG. 8 are designated by like reference numerals. 
The inlet passageway 92 is held in fluid communication at one end thereof 
with an inlet nozzle 70 of the radiator 68 and at the other end thereof 
with one end of the outlet passageway 94. The other end of the outlet 
passageway 94 is held in fluid communication with an outlet nozzle 76 of 
the radiator 68. The cooling liquid medium in the radiator 68 is naturally 
passed through the inlet and outlet passageways 92 and 94 and returned to 
the radiator 68 by heat generated in the electromagnetic induction heating 
coil 4 and by radiation of the radiator 68. It should be noted that the 
cooling liquid medium may be forcibly circulated by suitable circulation 
means provided in these passageways. The core 91 is further formed with a 
plurality of cooling plate portions 96 at a portion 97 thereof with which 
the inlet passageway 92 is formed. The cooling plate portions 96 are 
axially spaced apart with one another and extend radially inward toward a 
rotational shaft 8. On the rotational shaft 8 is mounted a cooling fin 98 
formed with a plurality of cooling fin portions 100 each extending 
radially outward between the adjacent cooling plate portions 96 of the 
core 91. Thus, the cooling plate portions 96 of the core 91 and the 
cooling fin portions 100 of the cooling fin 98 are alternately spaced 
apart with one another. Accordingly, the inner and outer races of a 
bearing 18 mounted on the rotational shaft 8 are cooled at the same time 
through the rotational shaft 8, the cooling plate portions 96 of the core 
91 and the cooling fin portions 100 of the cooling fin 98 while the 
cooling liquid medium is passing through the inlet passageway 92 of the 
core 91. As described above in the fifth embodiment, a cooling air is 
passed through radiator fin portions 90 of the radiator 68, as indicated 
by arrows D, by a cooling fan provided therefor. Thus, heat is forcibly 
radiated from the cooling liquid medium through the radiator fine portions 
90. The heat can be naturally radiated depending upon the outside 
temperature of the radiator 68 and upon the flow condition in the vicinity 
of the radiator 68. The other constructions and operations are 
substantially identical to the first embodiment of FIG. 1 and therefore 
the description will hereinafter be omitted. 
From the foregoing description regarding the second embodiment to sixth 
embodiment of the present invention, it will be seen that these 
embodiments also can obtain the same effect that is obtained by the first 
embodiment. 
Although it has been described that the electromagnetic induction heating 
coil 4 is used as heating means for heating the rotatable roller 2, it is 
noted that a heat medium such as, for example, steam and the like may be 
used as heating means. Although the present invention has been illustrated 
and described in conjunction with a cooling air or cooling liquid medium, 
it is noted that it may be also applied to other types of cooling fluid or 
a fluid cooled by suitable cooling means. Also, while it has been 
illustrated that the rotatable roller 2 is mounted directly on the 
rotational shaft 8, it is noted that it may be mounted on a shaft which is 
coupled to the rotational shaft 8. Furthermore, although the rotational 
shaft, bearing and bearing cooling apparatus are disposed inside the 
heating roller, it is noted that the present invention may be applied to 
the reverse arrangement. Furthermore, although it has been described that 
the inlet passageway is arranged inside and the outlet passageway is 
arranged outside, it is noted that the arrangement may be reversed. 
In accordance with the present invention, inlet and outlet passageways for 
a cooling medium are arranged between the heating roller and the means for 
circulating the cooling medium, and at least one of the inlet and outlet 
passageways extends along the bearing disposed adjacent the heating means 
and along the shaft and are disposed adjacent the bearing and the shaft. 
The bearing and the shaft are therefore cooled at the same time and the 
generating surface is increased. Furthermore, at least more than one fluid 
layer is provided between the heating roller and the bearing and therefore 
the adiabatic and radiation effect is increased. Thus, there is provided, 
according to the present invention, an improved bearing cooling apparatus 
of a heating roller which prevents damage of the bearing and degradation 
of the lubricating oil which are caused by the temperature difference 
between the outer and inner races. 
While certain representative embodiments and details have shown for the 
purpose of illustrating the present invention, it will be apparent to 
those skilled in this art that various changes and modifications may be 
made therein without departing from the spirit or scope of the invention.