JP7174118B2 - Fan shaft cooling mechanism - Google Patents

Description

The present invention relates to a fan shaft cooling mechanism in a fan for stirring the atmosphere in a heat treatment furnace.

In the case where the heat treatment furnace has a fan for stirring the atmosphere in the furnace, a configuration has been proposed in which the fan shaft provided in the furnace body suppresses the influence of heat received from the inside of the furnace.

Patent Literature 1 discloses a configuration in which a cooling fan is provided for a fan shaft positioned outside a furnace body, and the fan shaft and bearings are cooled by blowing air from the cooling fan. Patent Literature 2 discloses a configuration in which a fan shaft is cooled by a cooling tube spirally arranged around the outer circumference of a metal cylinder arranged around the fan shaft. Patent Document 3 discloses a configuration in which a heat insulating material is provided in the hollow portion of the fan shaft. Patent Literature 4 discloses a configuration in which a water jacket portion is provided in the lower peripheral region of the shaft seal portion.

JP 2014-185824 A Japanese Unexamined Patent Application Publication No. 2003-21472 JP 2014-163637 A Japanese Utility Model Publication No. 57-52101

In the above-mentioned patent document, in order to protect the bearings and seals, some kind of temperature rise suppressing means (cooling means or heat insulating means) is newly provided separately from the fan shaft. Providing a new temperature rise suppressing means separate from the fan shaft causes problems such as an increase in the number of parts and a need for an installation space.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fan shaft cooling mechanism that does not increase the number of parts and does not require a new installation space.

In order to solve the above problems, a fan shaft cooling mechanism according to an aspect of the present invention includes:
a through hole connecting the interior and exterior of a furnace body in a heat treatment furnace;
a drive source disposed outside the furnace body; blades disposed inside the furnace body; and a fan shaft inserted through the through-hole to transmit rotational driving force from the drive source to the blades. a fan having
a cooling unit disposed in the furnace body so as to surround the through hole,
A stirring portion for stirring gas existing in a gap formed between the through-hole and the fan shaft is provided on the outer peripheral portion of the fan shaft so as to correspond to the cooling portion.

According to the present invention, the gas existing in the gap is stirred by the stirring section provided on the outer peripheral portion of the fan shaft, thereby promoting heat dissipation from the high-temperature fan shaft to the cooling section, thereby effectively cooling the fan shaft. Therefore, it is possible to avoid an increase in the number of parts and eliminate the need for a new installation space.

FIG. 4 is a cross-sectional view schematically explaining a cooling mechanism for a fan shaft according to the first embodiment; FIG. 2 is a cross-sectional view of the cooling mechanism of the fan shaft shown in FIG. 1 taken along line II-II; 3 is an enlarged view of a main part of FIG. 2; FIG. FIG. 8 is an enlarged cross-sectional view of a main part schematically illustrating a cooling mechanism for a fan shaft according to a second embodiment; FIG. 11 is an enlarged cross-sectional view of a main part schematically illustrating a fan shaft cooling mechanism according to a third embodiment;

An embodiment of a fan shaft cooling mechanism 40 according to the present invention will be described below with reference to the drawings.

[First embodiment]
A cooling mechanism 40 for the fan shaft 14 according to the first embodiment will be described with reference to FIGS. 1 to 3. FIG. FIG. 1 is a cross-sectional view schematically explaining a cooling mechanism 40 for a fan shaft 14 according to the first embodiment. FIG. 2 is a cross-sectional view of the cooling mechanism 40 for the fan shaft 14 shown in FIG. 1 taken along line II-II. 3 is an enlarged view of a main part of FIG. 2. FIG. 2 and 3, the arrows at the fan shaft 14 indicate the rotation of the fan shaft 14, and in FIG.

As shown in FIG. 1 , the heat treatment furnace 1 has a furnace body 4 . A furnace body 4 has a heat insulating material 2 and a furnace shell 3 . The work is heat-treated in the heat-treating space formed inside the heat insulating material 2 . A furnace shell 3 covers the outer portion of the insulation 2 and serves as a housing for the furnace body 4 . For example, a cylindrical through-hole 5 is formed in the upper portion of the furnace body 4 . The through hole 5 connects the inside and the outside of the furnace body 4 and penetrates the heat insulating material 2 and the furnace shell 3 of the furnace body 4 in the vertical direction, for example.

For example, a fan 10 is provided above the furnace body 4 . The fan 10 is, for example, a stirring fan that stirs the atmosphere in the heat treatment space. The fan 10 has blades 12 , a fan shaft 14 and bearings 16 . The fan shaft 14 is made of, for example, heat-resistant steel having a cylindrical shape extending in the vertical direction, and is inserted through the through hole 5 . The fan shaft 14 inserted through the through hole 5 is separated from the heat insulating material 2 in which the through hole 5 is formed by a gap 7 . On the side of the bearing 16 of the through hole 5 through which the fan shaft 14 is inserted, a seal 18 abutting against the furnace shell 3 prevents the atmosphere inside the furnace body 4 from leaking to the outside of the furnace body 4. there is

A blade 12 is attached to one end (for example, the lower end) of the fan shaft 14 . The blades 12 stir the atmosphere in the heat treatment space. A driving source 11 (for example, a motor) is connected to the other end (for example, the upper end) of the fan shaft 14 . The drive source 11 is arranged outside the furnace body 4 and drives the fan shaft 14 to rotate. The fan shaft 14 is rotatably supported by bearings 16 . A bearing 16 is arranged between the drive source 11 and the seal 18 .

A cooling part 20 is arranged in the heat insulating material 2 so as to surround the through hole 5 . The cooling section 20 has a cooling jacket 21 , an inlet pipe 22 and an outlet pipe 23 . The cooling jacket 21 is composed of a metal portion 24 made of heat-resistant steel or the like, and the introduction pipe 22 and the discharge pipe 23 are composed of metal pipes 25 made of heat-resistant steel or the like. Cooling jacket 21 is disposed near through hole 5 so as to surround through hole 5 and extends in the axial direction of through hole 5 . The inlet pipe 22 communicates with the cooling jacket 21 , and the cooling jacket 21 communicates with the discharge pipe 23 . A cooling fluid (for example, cooling water W) is supplied from the inlet pipe 22 , flows through the cooling jacket 21 , and is discharged from the discharge pipe 23 . As a result, gas existing in the gap 7 (for example, air or atmosphere gas, hereinafter simply referred to as gas) is cooled, and the fan shaft 14 is cooled via the cooled gas.

When the gap 7 is at a close distance, the heat possessed by the fan shaft 14 is radiated to the cooling jacket 21 of the cooling section 20 by radiation. In other words, the heat of the fan shaft 14 is transferred to the cooling water W flowing through the cooling jacket 21 by radiation. Therefore, the cooling jacket 21 of the cooling section 20 works as a cooling mechanism 40 for the fan shaft 14 .

The fan shaft 14 has at least one stirring portion 30 on its outer circumference. As shown in FIG. 1 , the stirring section 30 is provided on the outer peripheral portion of the fan shaft 14 so as to correspond to the axial length of the cooling jacket 21 of the cooling section 20 . The fan shaft 14 exemplified in FIG. 2 has eight grooves 30 that act as stirrers 30 . The groove 30 is recessed from the outer peripheral surface of the fan shaft 14 and extends in the axial direction of the fan shaft 14 . As a result, the stirring portion in the axial direction where the gas existing in the gap 7 is stirred becomes longer, so that the cooling efficiency is improved and the fan shaft 14 can be cooled more effectively. The groove 30 can be easily formed by machining the outer peripheral portion of the fan shaft 14 . As shown in FIGS. 2 and 3, the groove 30 has, for example, a rectangular concave shape in a cross-sectional view in the direction orthogonal to the axis. Note that the groove 30 may have various recessed shapes such as a semi-circular recessed shape, a semi-elliptical recessed shape, and a triangular recessed shape in a cross-sectional view in the direction orthogonal to the axis.

As schematically shown in FIG. 3, grooves 30 functioning as agitator 30 fill gaps 7 formed between the inner peripheral surface of through-hole 5 and the outer peripheral surface of fan shaft 14 when fan shaft 14 rotates. agitate the gas present. Agitation of the gas present in the gap 7 causes heat transfer due to gas convection. In other words, the heat of the fan shaft 14 is transferred to the cooling jacket 21 by convection. Accordingly, the grooves 30 of the fan shaft 14 act as a cooling mechanism 40 for the fan shaft 14 .

Since the heat dissipation by convection is added to the heat dissipation by radiation, the cooling efficiency is improved and the fan shaft 14 can be cooled effectively. Further, since the groove 30 functioning as the stirring portion 30 is formed only by processing the outer peripheral portion of the fan shaft 14, the number of parts does not increase and a new installation space is not required.

Therefore, according to the cooling mechanism 40 for the fan shaft 14 according to the first embodiment, the gas existing in the gap 7 is stirred by the groove (stirring portion) 30 provided on the outer peripheral portion of the fan shaft 14 to cool the fan shaft 14 . Since it can be cooled effectively, it is possible to avoid increasing the number of parts and eliminating the need for a new installation space.

[Second embodiment]
A cooling mechanism 40 for the fan shaft 14 according to the second embodiment will be described with reference to FIG. FIG. 4 is an enlarged cross-sectional view of a main part schematically explaining a cooling mechanism 40 for the fan shaft 14 according to the second embodiment. In FIG. 4, the arrows at the fan shaft 14 indicate the rotation of the fan shaft 14, and the arrows at the gap 7 indicate the flow of gas present in the gap 7. As shown in FIG. In the cooling mechanism 40 for the fan shaft 14 according to the second embodiment, the grooves 30 extend obliquely with respect to the axial direction of the fan shaft 14, which is different from the cooling mechanism 40 for the fan shaft 14 according to the first embodiment. are different.

The fan shaft 14 illustrated in FIG. 4 has a plurality of (e.g., eight) grooves 30 that act as agitators 30 . The groove 30 is provided on the outer peripheral portion of the fan shaft 14 so as to correspond to the axial length of the cooling jacket 21 of the cooling section 20 . The groove 30 is recessed in the outer peripheral surface of the fan shaft 14 and extends obliquely with respect to the axial direction of the fan shaft 14 . For example, the groove 30 has an end on the bearing 16 side located forward in the rotation direction on the circumference of the fan shaft 14 and an end on the blade 12 side on the rotation direction rearward on the circumference of the fan shaft 14 . It extends diagonally with respect to the axial direction of the fan shaft 14 so as to be located on the side. In other words, when the fan shaft 14 rotates counterclockwise as viewed from the bearing 16 side, the groove 30 extends obliquely from the upper right to the lower left of the fan shaft 14 as viewed from the side in FIG. configured to exist. As a result, when the fan shaft 14 rotates, the gas existing in the gap 7 flows toward the blades 12 , making it difficult for the heat of the fan shaft 14 to be transmitted to the bearing 16 .

Therefore, when the fan shaft 14 rotates, the gas present in the gap 7 is agitated, and the gas present in the gap 7 flows toward the blades 12, causing heat transfer due to gas convection, resulting in cooling efficiency. is improved, and the fan shaft 14 can be effectively cooled. Therefore, the grooves 30 obliquely extending with respect to the axial direction of the fan shaft 14 act as a cooling mechanism 40 for the fan shaft 14 .

The grooves 30 extending obliquely with respect to the axial direction of the fan shaft 14 illustrated in FIG. 4 can be easily formed by machining the outer peripheral portion of the fan shaft 14 . The groove 30 has, for example, a rectangular concave shape in a cross-sectional view in the direction perpendicular to the axis. Note that the groove 30 may have various recessed shapes such as a semi-circular recessed shape, a semi-elliptical recessed shape, and a triangular recessed shape in a cross-sectional view in the direction orthogonal to the axis.

[Third embodiment]
A cooling mechanism 40 for the fan shaft 14 according to the third embodiment will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional view of a main part schematically explaining a cooling mechanism 40 for the fan shaft 14 according to the third embodiment. In FIG. 5, the arrows at the fan shaft 14 indicate the rotation of the fan shaft 14, and the arrows at the gap 7 indicate the flow of gas present in the gap 7. As shown in FIG. The cooling mechanism 40 for the fan shaft 14 according to the third embodiment differs from the cooling mechanism 40 for the fan shaft 14 according to the first embodiment in that the groove 30 has a helical shape like a screw.

The fan shaft 14 exemplified in FIG. 5 has one groove 30 that acts as an agitating portion 30 . The groove 30 is provided on the outer peripheral portion of the fan shaft 14 so as to correspond to the axial length of the cooling jacket 21 of the cooling section 20 . The groove 30 is recessed with respect to the outer peripheral surface of the fan shaft 14 and has a helical shape like a male screw. For example, the groove 30 has an end on the bearing 16 side located forward in the rotation direction on the circumference of the fan shaft 14 and an end on the blade 12 side on the rotation direction rearward on the circumference of the fan shaft 14 . It extends diagonally with respect to the axial direction of the fan shaft 14 so as to be located on the side. In other words, when the fan shaft 14 rotates counterclockwise as viewed from the bearing 16 side, the groove 30 slants from the upper right to the lower left of the fan shaft 14 in a side view of FIG. Constructed to extend like writing. As a result, when the fan shaft 14 rotates, the groove 30 having the helical shape allows the gas existing in the gap 7 to flow toward the blades 12 , thereby making it difficult for the heat of the fan shaft 14 to be transmitted to the bearing 16 .

Therefore, when the fan shaft 14 rotates, the gas present in the gap 7 is agitated, and the gas present in the gap 7 flows toward the blades 12, causing heat transfer due to gas convection, resulting in cooling efficiency. is improved, and the fan shaft 14 can be effectively cooled. Therefore, the groove 30 having a helical shape like an external thread acts as a cooling mechanism 40 for the fan shaft 14 .

The groove 30 having a helical shape like a male screw, illustrated in FIG. 5, can be easily formed by machining the outer peripheral portion of the fan shaft 14 . The groove 30 has, for example, a rectangular concave shape in a cross-sectional view in the direction orthogonal to the axis. Note that the groove 30 may have various concave shapes such as a semi-circular concave shape, a semi-elliptical concave shape, and a V-shaped concave shape when viewed in cross section in the direction perpendicular to the axis.

As the stirring part 30 having a concave shape, the groove 30 which is an elongated recess is exemplified. A mode in which a plurality of minute concave portions having a trapezoidal shape or the like are dispersedly arranged can also be used.

The stirring portion 30 provided on the outer peripheral portion of the fan shaft 14 may have a convex shape protruding radially outward from the outer peripheral surface. At least one convex stirring portion 30 is provided on the outer peripheral portion of the fan shaft 14 and extends so as to correspond to the axial length of the cooling jacket 21 of the cooling portion 20 . The convex shape can be reversed to the above concave shape, and the convex stirring part 30 has, for example, a semi-circular convex shape, a semi-elliptical convex shape, or a V-shaped convex shape in a cross-sectional view in the direction perpendicular to the axis. Elongated protrusions may be used, or a plurality of minute protrusions having a bump protrusion shape (small circular protrusion), a polygonal prism concave shape, a polygonal pyramidal convex shape, a polygonal truncated pyramidal convex shape, etc. may be dispersedly arranged. can also

As an example of numerical values that do not limit the present invention, when the outer diameter of the fan shaft 14 is 100 mm, the depth of the groove 30 is 1 to 5 mm, and the distance of the gap 7 in the direction perpendicular to the axis is 5 to 20 mm. In other words, the depth of the groove 30 is 1 to 5% of the outer diameter of the fan shaft 14, and the distance of the gap 7 in the orthogonal direction to the outer diameter of the fan shaft 14 is 5 to 20%.

Although specific embodiments and numerical values of the present invention have been described, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

The present invention and embodiments are summarized as follows.

A cooling mechanism 40 for the fan shaft 14 according to one aspect of the present invention includes:
a through hole 5 connecting the inside and the outside of the furnace body 4 in the heat treatment furnace 1;
A driving source 11 arranged outside the furnace body 4, a blade 12 arranged inside the furnace body 4, and a rotational driving force from the driving source 11 inserted through the through hole 5. a fan 10 having a fan shaft 14 that communicates with the blades 12;
A cooling unit 20 arranged in the furnace body 4 so as to surround the through hole 5,
A stirring portion 30 for stirring the gas existing in the gap 7 formed between the through hole 5 and the fan shaft 14 is provided on the outer peripheral portion of the fan shaft 14 so as to correspond to the cooling portion 20. Characterized by

According to the above configuration, the gas existing in the gap 7 is stirred by the stirring section 30 provided on the outer peripheral portion of the fan shaft 14, thereby promoting heat transfer to the cooling section 20 and effectively moving the fan shaft 14. Since it can be cooled, it is possible to prevent an increase in the number of parts and eliminate the need for a new installation space.

Further, in the cooling mechanism 40 of the fan shaft 14 of one embodiment,
The stirring part 30 has a concave shape.

According to the above embodiment, it can be easily formed by machining the outer peripheral portion of the fan shaft 14 .

Further, in the cooling mechanism 40 of the fan shaft 14 of one embodiment,
The stirring part 30 having the concave shape is a groove 30 .

According to the above embodiment, it can be easily formed by machining the outer peripheral portion of the fan shaft 14 .

Further, in the cooling mechanism 40 of the fan shaft 14 of one embodiment,
The groove 30 extends in the axial direction of the fan shaft 14 .

According to the above-described embodiment, the length of the agitated portion in the axial direction where the gas present in the gap 7 is agitated increases the cooling efficiency, so that the fan shaft 14 can be cooled more effectively.

Further, in the cooling mechanism 40 of the fan shaft 14 of one embodiment,
The groove 30 extends obliquely with respect to the axial direction of the fan shaft 14 .

According to the above embodiment, when the fan shaft 14 rotates, the gas existing in the gap 7 flows toward the blades 12 , and the heat of the fan shaft 14 is less likely to be transmitted to the bearing 16 .

REFERENCE SIGNS LIST 1 heat treatment furnace 2 heat insulating material 3 furnace shell 4 furnace body 5 through hole 7 gap 10 fan 11 drive source 12 blade 14 fan shaft 16 bearing 18 seal 20 cooling part 21 cooling Jacket 22... Introduction pipe 23... Discharge pipe 24... Metal part 25... Metal pipe 30... Groove (stirring part)
40... Cooling mechanism W... Cooling water

Claims (5)

a through hole connecting the interior and exterior of a furnace body in a heat treatment furnace;
a drive source disposed outside the furnace body; blades disposed inside the furnace body; and a fan shaft inserted through the through-hole to transmit rotational driving force from the drive source to the blades. a fan having
a cooling unit disposed in the furnace body so as to surround the fan shaft ;
A stirring portion for stirring gas existing in a gap formed between the cooling portion and the fan shaft is provided on an outer peripheral portion of the fan shaft so as to face the cooling portion,
Fan shaft cooling mechanism. 2. The fan shaft cooling mechanism according to claim 1, wherein said stirring portion has a concave shape. 3. The fan shaft cooling mechanism according to claim 2, wherein the stirring portion having the concave shape is a groove. 4. The fan shaft cooling mechanism according to claim 3, wherein the groove extends in the axial direction of the fan shaft. 4. The fan shaft cooling mechanism according to claim 3, wherein the groove extends obliquely with respect to the axial direction of the fan shaft.

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