JP2014037903A - Agitation fan for thermal treatment device and thermal treatment device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an agitation fan for a thermal treatment device which extends its life and achieves weight reduction.SOLUTION: An agitation fan 7 includes: a shaft part 20; and multiple blade parts 40 which radially extend from the shaft part 20. A blade fixing part 22 of the shaft part 20 includes a cylindrical part 29 extending in an axial direction S1. A hole part 30 of the cylindrical part 29 opens on one end surface 29a forming one end surface of the shaft part 20. A thickness T1 of the cylindrical part 29 is set so as to be the same or substantially the same as a thickness T2 of a root part 41 of the blade part 40.

Description

  The present invention relates to a stirring fan for a heat treatment apparatus and a heat treatment apparatus including the same.

  A fan as a stirring member for a heat treatment furnace is known (for example, see Patent Document 1). The fan described in Patent Document 1 is used for stirring a gas having a high temperature of about several hundred degrees. This fan has an impeller, a rotating shaft with the impeller attached to the lower end, and a bearing that supports the rotating shaft. The impeller has a boss fixed to the rotating shaft and a plurality of blades coupled to the outer periphery of the boss.

JP-A-8-291978 ([0006], [0007])

  The fan needs to rotate at a high speed in order to ensure a sufficient air volume. For this reason, it is necessary to prevent abnormal vibration from occurring in the fan due to the high-speed rotation operation. Therefore, the weight balance of the fan is usually adjusted. Thereby, the abnormal vibration at the time of rotation of a fan is suppressed. Thereby, the load which acts on a fan can be made small and, as a result, the lifetime of a fan can be made longer.

  By the way, in a heat treatment furnace, a component at room temperature may be disposed in the vicinity of a fan heated to a high temperature in advance, and the component may be heated with a heater from this state. In this case, the component is at a low temperature until it is heated by the heater. For this reason, the fan receives cold air from around the parts. For this reason, the temperature of the surface of the fan is suddenly lowered by the cold air. On the other hand, the temperature inside the fan does not drop rapidly. As a result, the temperature gradient in the fan, particularly the temperature gradient between the blade root and the boss, becomes excessively large. As a result, a large thermal stress is generated in the fan blades. When the heat treatment of the components is repeatedly performed, a large thermal stress acts repeatedly on the fan blades, and abnormalities such as cracks occur in the fan. In other words, the fan reaches the end of its life early.

  Here, it is conceivable to increase the blade strength by increasing the blade thickness. In this case, the thermal stress generated in the blade can be reduced. However, in such a configuration, the mass of the fan increases, and a large load acts on the bearing that supports the rotating shaft. For this reason, although the life of the fan itself is extended, the life of the member supporting the fan is reduced.

  In view of the above circumstances, an object of the present invention is to provide a stirring fan for a heat treatment apparatus that can have a longer life and can achieve weight reduction.

  (1) In order to solve the above problems, a stirring fan for a heat treatment apparatus according to an aspect of the present invention includes a shaft portion and a plurality of blade portions extending radially from the shaft portion. The shaft portion includes a blade fixing portion that fixes each of the blade portions. The blade fixing portion has a cylindrical portion extending in the axial direction of the shaft portion. The hole portion of the cylindrical portion is open to one end surface of the shaft portion. Each of the blade portions has a root portion continuous with the cylindrical portion. The thickness of the cylindrical portion is set in the range of 75% to 125% of the thickness of the root portion.

  According to this configuration, the cylindrical portion is formed in the blade fixing portion. Thereby, the heat capacity of the part which continues to the base part of a blade | wing part among cylindrical parts becomes a value close | similar to the heat capacity of a base part. Thereby, for example, even when cold air from a product to be heat-treated comes into contact with a high-temperature stirring fan, the difference between the temperature of the cylindrical portion and the temperature of the root portion of the blade portion can be further reduced. . That is, the temperature gradient between the cylindrical portion and the root portion of the blade portion can be further reduced. Therefore, the thermal stress which arises in the base part of a blade | wing part can be made small. In addition, the cylindrical portion has an inner peripheral surface in addition to the outer peripheral surface, and has a large surface area. That is, the cylindrical portion can ensure a large surface area, like the blade portion. For this reason, when the cool air from the article to be processed comes into contact with the high-temperature stirring fan, the speed at which the cylindrical part is cooled can be close to the speed at which the root part is cooled. Therefore, the temperature gradient between the cylindrical portion and the root portion of the blade portion can be further reduced. In particular, when the thickness of the cylindrical portion is set to 100% of the thickness of the root portion, the above-described temperature gradient can be remarkably reduced. Thereby, since the thermal stress which arises in the base part of a blade | wing part can be made very small, the lifetime of a fan can be lengthened more. Further, the thickness range of the cylindrical portion is set between the above lower limit and the upper limit. Thereby, the effect substantially the same as the case where the thickness of a cylindrical part is made the same with the thickness of a root part can be exhibited.

  In addition, the cylindrical portion is lightweight because it is hollow. Therefore, the weight of the stirring fan can be reduced. Thereby, the load to support members, such as a bearing which supports a stirring fan, can be made small. Therefore, the lifetime of the entire heat treatment apparatus including the stirring fan can be extended.

  Therefore, according to the present invention, in the stirring fan for the heat treatment apparatus, the life can be further extended and the weight can be reduced.

  (2) Preferably, each said blade | wing part has an edge part which continues to the said one end surface of the said axial part, and the other edge part arrange | positioned apart from this one edge part in the said axial direction. . The shortest distance between the other edge portion and the hole portion is set to be equal to or larger than the radius of the portion of the shaft portion adjacent to the blade fixing portion.

  According to this configuration, the coupling strength between the blade portion and the shaft portion can be sufficiently ensured. For this reason, even when the stirring fan rotates at a high speed, the tensile stress generated at the root of the blade due to the centrifugal force of the blade does not need to be excessively increased. Therefore, the allowable rotation speed of the stirring fan can be sufficiently increased. That is, the high-temperature gas in the heat treatment apparatus can be sufficiently stirred by the high-speed rotation of the stirring fan.

  (3) Preferably, the said blade | wing fixing | fixed part and each said blade | wing part are mutually integrally formed by casting or welding.

  According to this configuration, it is possible to suppress the occurrence of cracks in a cast agitating fan in which cracks due to thermal stress are likely to occur. Similarly, the occurrence of cracks can be suppressed in a stirring member having a welded portion where cracks due to thermal stress are likely to occur.

  (4) A heat treatment apparatus according to an aspect of the present invention includes a treatment chamber for heat treating an article to be treated, and the stirring fan. The stirring fan is disposed in the processing chamber.

  According to this configuration, the cylindrical portion is formed in the blade fixing portion. Thereby, the heat capacity of the part which continues to the base part of a blade | wing part among cylindrical parts becomes a value close | similar to the heat capacity of a root part. Thereby, for example, even when cold air from a product to be heat-treated comes into contact with a high-temperature stirring fan, the difference between the temperature of the cylindrical portion and the temperature of the root portion of the blade portion can be further reduced. . That is, the temperature gradient between the cylindrical portion and the root portion of the blade portion can be further reduced. Therefore, the thermal stress which arises in the base part of a blade | wing part can be made small. In addition, the cylindrical portion has an inner peripheral surface in addition to the outer peripheral surface, and has a large surface area. That is, the cylindrical portion can ensure a large surface area, like the blade portion. For this reason, when the cool air from the article to be processed comes into contact with the high-temperature stirring fan, the speed at which the cylindrical part is cooled can be close to the speed at which the root part is cooled. Therefore, the temperature gradient between the cylindrical portion and the root portion of the blade portion can be further reduced. In particular, when the thickness of the cylindrical portion is set to 100% of the thickness of the root portion, the above-described temperature gradient can be remarkably reduced. Thereby, since the thermal stress which arises in the base part of a blade | wing part can be made very small, the lifetime of a fan can be lengthened more. Further, the thickness range of the cylindrical portion is set between the above lower limit and the upper limit. Thereby, the effect substantially the same as the case where the thickness of a cylindrical part is made the same with the thickness of a root part can be exhibited.

  In addition, the cylindrical portion is lightweight because it is hollow. Therefore, the weight of the stirring fan can be reduced. Thereby, the load to support members, such as a bearing which supports a stirring fan, can be made small. Therefore, the lifetime of the entire heat treatment apparatus including the stirring fan can be extended.

  Therefore, according to the present invention, in the heat treatment apparatus, the life can be further extended and the weight can be reduced.

  (5) Preferably, it is further provided with the receiving part arrange | positioned in the said process chamber and receiving a to-be-processed goods. The agitation fan is arranged in a posture in which the cylindrical portion and the receiving portion face each other.

  According to this configuration, the cold air from the article to be processed received by the receiving portion is mainly transmitted to the cylindrical portion and the root portion of the blade portion of the stirring fan. Even when the stirring fan is in a high temperature state, the temperature gradient generated between the cylindrical portion and the blade portion due to the cold air is small. Therefore, even when the temperature difference between the stirring fan and the article to be processed is large, the thermal stress generated at the root portion of the blade portion can be reduced. Therefore, the life of the stirring fan can be further extended.

  According to the present invention, in the stirring fan for the heat treatment apparatus, the life can be further extended and the weight can be reduced.

It is a typical side view of the heat processing apparatus which concerns on embodiment of this invention, and has shown the state which cut | disconnected a part. It is a perspective view of a stirring fan, and has shown the state which looked at the stirring fan from the one end side. It is a perspective view of a stirring fan, and has shown the state which looked at the stirring fan from the other end side. It is a side view of a stirring fan. It is sectional drawing which follows the VV line of FIG. It is a bottom view of the stirring fan, and shows a state in which main parts of the stirring fan are viewed from the axial direction of the stirring fan. It is sectional drawing of the principal part for demonstrating the modification of this invention. It is sectional drawing of an Example and a comparative example. It is a graph which shows the result regarding each temperature of an Example and a comparative example. It is a graph which shows the result of having compared the stress of the one end part of the root part in a blade | wing part about each of an Example and a comparative example. It is a graph which shows the result of having compared the stress of the other end part of the root part in a blade | wing part about each of an Example and a comparative example.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The present invention can be widely applied as a stirring fan for a heat treatment apparatus.

[Outline of heat treatment equipment]
FIG. 1 is a schematic side view of a heat treatment apparatus 1 according to an embodiment of the present invention, showing a state where a part thereof is cut. Referring to FIG. 1, a heat treatment apparatus 1 is provided for heat treating a workpiece 100. Examples of the heat treatment include carburizing, quenching, tempering, nitriding, and annealing. In the present embodiment, a case where the heat treatment apparatus 1 is a gas carburizing furnace will be described as an example. In the present embodiment, the article to be processed 100 is a metal part. The heat treatment apparatus 1 is configured to carburize a plurality of workpieces 100 accommodated in a container 101.

  The heat treatment apparatus 1 is provided as a batch type heat treatment apparatus. Specifically, the heat treatment apparatus 1 heats the article to be treated 100 in a state where a certain amount of the article to be treated 100 is accommodated in a lump. After the heat treatment, the article 100 is discharged from the heat treatment apparatus 1 at a time.

  The heat treatment apparatus 1 includes a processing chamber 2, an entrance door 3, an exit door 4, a transfer device 5, a heater 6, and a stirring fan 7.

  The processing chamber 2 is formed in a box shape. The processing chamber 2 is configured to be able to accommodate the product to be processed 100, and is configured to be supplied with a gas for heat treating the product to be processed 100. Examples of this gas include acetylene and ethylene. The processing chamber 2 has an inlet 8 and an outlet 9.

  The entrance 8 of the processing chamber 2 can be opened and closed by the entrance door 3. The container 101 containing the workpiece 100 is conveyed from the outside of the processing chamber 2 to the inside of the processing chamber 2 through the inlet 8. The outlet 9 of the processing chamber 2 can be opened and closed by the outlet door 4. The container 101 and the article to be processed 100 in the processing chamber 2 are conveyed from the inside of the processing chamber 2 to the outside of the processing chamber 2 through the outlet 9.

  The entrance door 3 and the exit door 4 are closed when the workpiece 100 is heat-treated in the processing chamber 2. The container 101 and the article to be processed 100 are transferred through the processing chamber 2 by the transfer device 5.

  The conveying device 5 has a plurality of rollers 10 as conveying members and receiving portions. The plurality of rollers 10 are disposed between the inlet 8 and the outlet 9 in the processing chamber 2. The plurality of rollers 10 are arranged at intervals along the conveyance direction A1 as the direction from the inlet 8 toward the outlet 9. The container 101 containing the article to be processed 100 is transported on the plurality of rollers 10 in the transport direction A1. The workpiece 100 is received in the processing chamber 2 by the roller 10. In this state, the article to be processed 100 is heated by the heater 6.

  The heater 6 is an electric heater, for example, and is configured to heat the gas in the processing chamber 2. During the heat treatment of the workpiece 100, the heater 6 heats the gas in the processing chamber 2 to about 1000 ° C. This temperature is preferably about 800 ° C., more preferably about 900 ° C.

  In the present embodiment, the heater 6 has a portion disposed in the processing chamber 2. This portion is arranged in a meandering manner, and meanders up and down in the processing chamber 2 when proceeding in the transport direction A1. In the intermediate region 11 between the inlet 8 and the outlet 9 in the transport direction A1, the heater 6 is located in the upper part in the processing chamber 2. A stirring fan 7 is disposed in the intermediate region 11.

  The stirring fan 7 is provided for stirring the gas in the processing chamber 2. The stirring fan 7 can quickly raise or cool the article 100 to be processed in the processing chamber 2. Further, the temperature distribution of the gas in the processing chamber 2 can be made more uniform by the stirring fan 7.

  The stirring fan 7 is disposed in the upper part of the processing chamber 2. The workpiece 100 is disposed below the stirring fan 7 when being heat-treated. The stirring fan 7 is rotatably supported by the processing chamber 2. Further, the stirring fan 7 is rotated by a driving device such as an electric motor (not shown). By driving the driving device, the stirring fan 7 rotates to stir the gas in the processing chamber 2.

  When the article 100 to be processed is heat-treated by the heat treatment apparatus 1 having the above-described configuration, first, the entrance door 3 is opened. Next, the container 101 containing the article to be processed 100 is put into the processing chamber 2 from the inlet 8. In this case, the temperature of the container 101 and the temperature of the article to be processed 100 are, for example, room temperature and about 20 ° C. The container 101 and the article to be processed 100 are transported in the transport direction A <b> 1 by the transport device 5 and are disposed below the stirring fan 7.

  Next, electric power is supplied to the heater 6 in a state where the entrance door 3 and the exit door 4 are closed. Thereby, the gas in the processing chamber 2 is heated. Further, the stirring fan 7 is rotated. Thereby, the gas in the processing chamber 2 is stirred. Thereby, the concentration distribution of the gas in the processing chamber 2 is leveled, and the temperature of the gas in the processing chamber 2 is leveled.

  The temperature in the processing chamber 2 is raised to the temperature described above. Thereby, the to-be-processed goods 100 are heat-processed. After the heat treatment is completed, the exit door 4 is opened. Further, the transport device 5 operates. As a result, the container 101 is discharged to the outside of the processing chamber 2 through the outlet 9.

[Detailed configuration of stirring fan]
FIG. 2 is a perspective view of the stirring fan 7 and shows the stirring fan 7 as viewed from one end side. FIG. 3 is a perspective view of the stirring fan 7 and shows the stirring fan 7 viewed from the other end side. FIG. 4 is a side view of the stirring fan 7. FIG. 5 is a cross-sectional view taken along line VV in FIG. FIG. 6 is a bottom view of the stirring fan 7 and shows a state in which main parts of the stirring fan 7 are viewed from the axial direction of the stirring fan 7.

  With reference to FIGS. 2-6, in this embodiment, the stirring fan 7 is a centrifugal fan, and it is comprised so that the wind which goes to the outward of radial direction R1 of the stirring fan 7 may be generated. In the following, the axial direction S1 of the stirring fan 7 is simply referred to as “axial direction S1”. In the present embodiment, the direction parallel to the axial direction S1 is also referred to as the axial direction S1. The radial direction R1 of the stirring fan 7 is simply referred to as “radial direction R1”. The circumferential direction C1 of the stirring fan 7 is simply referred to as “circumferential direction C1”. In the present embodiment, the axial direction S1 is a vertical direction, and the radial direction R1 is a horizontal direction.

  The stirring fan 7 is made of a metal material such as heat resistant steel. The manufacturing method of the stirring fan 7 is not particularly limited. For example, the stirring fan 7 can be formed by pouring a molten metal material into a mold. More specifically, the stirring fan 7 can be formed by a die casting method, a lost wax method, or the like. In this embodiment, the stirring fan 7 is formed by die casting.

  The rotation speed of the stirring fan 7 is set to 100 rpm to 1600 rpm, for example. If the rotational speed of the stirring fan 7 is equal to or higher than the above lower limit, the air volume generated by the stirring fan 7 can be sufficiently increased. The lower limit of the rotation speed of the stirring fan 7 is more preferably 500 rpm. Moreover, if the rotational speed of the stirring fan 7 is below the above upper limit, it is possible to suppress an excessive increase in centrifugal force of the blade portion 40 described later of the stirring fan 7. As a result, it is possible to prevent the tensile stress of the stirring fan 7 from becoming excessively large, so that the life of the stirring fan 7 can be further extended. Moreover, the stirring fan 7 is completed through the mass balance adjustment work. Thereby, it is suppressed that a vibration arises when the stirring fan 7 rotates.

  The stirring fan 7 includes a shaft portion 20 and a plurality of blade portions 40.

  The shaft portion 20 is provided as a member extending in the axial direction S1. The outer shape of the shaft portion 20 viewed from the axial direction S1 is a circle.

  The shaft portion 20 includes a main shaft portion 21 and a blade fixing portion 22.

  The main shaft portion 21 is formed in a solid column shape. That is, the main shaft portion 21 is provided as a columnar member whose inside is clogged. The main shaft portion 21 has one end portion 23, a main shaft main body 24, a tapered portion 25, and the other end portion 26. The other end portion 26, the tapered portion 25, the main spindle body 24, and the one end portion 23 are arranged in this order along the axial direction S1.

  The other end portion 26 constitutes the other end portion of the main shaft portion 21 in the axial direction S <b> 1 and constitutes the other end portion of the stirring fan 7. The other end 26 is formed in a cylindrical shape. The other end 26 is configured to receive a driving force from an electric motor (not shown). The other end portion 26 is continuous with the tapered portion 25. The tapered portion 25 is formed in a truncated cone shape. The diameter of the taper-shaped portion 25 is increased toward the one end portion 23 side. The tapered portion 25 is continuous with the main spindle body 24.

  The main shaft body 24 is formed in a columnar shape, and extends in the axial direction S1. The outer peripheral surface of the main spindle body 24 is fitted with bearings 27 and 27. One or a plurality of bearings 27 are provided. In the present embodiment, two bearings 27 are provided. These bearings 27, 27 are arranged in a state of being separated from each other in the axial direction S1. Each bearing 27, 27 is held by the bearing holding portion 12 (see FIGS. 1 and 4) of the processing chamber 2. Thus, the stirring fan 7 is rotatably supported by the processing chamber 2 via the bearings 27 and 27. The rotation direction of the stirring fan 7 is one of the circumferential directions C1. The main spindle body 24 is continuous with the one end portion 23.

  The one end portion 23 is provided as a portion extending outward in the radial direction R1 as it proceeds to the blade portion 40 side. The one end portion 23 is formed in a substantially truncated cone shape. More specifically, the one end portion 23 is formed in a shape in which an intermediate portion in the axial direction S1 is recessed inward in the radial direction R1 in the outer peripheral portion of the truncated cone. The diameter of the one end portion 23 is increased as the portion is closer to the blade fixing portion 22. At the boundary portion between the one end portion 23 and the main spindle body 24, the diameter of the one end portion 23 and the diameter of the main spindle body 24 are the same. One end 23 a of the one end portion 23 is continuous with the other end 22 a of the blade fixing portion 22.

  The blade fixing portion 22 is provided to fix the plurality of blade portions 40. That is, the blade fixing portion 22 is provided as a portion coupled to the blade portion 40. The blade fixing portion 22 forms one end portion of the main shaft portion 21. In the axial direction S <b> 1, the length of the blade fixing portion 22 is set to be shorter than the length of the main spindle body 24.

  The blade fixing part 22 has a solid part 28 and a cylindrical part 29. The solid portion 28 and the cylindrical portion 29 are arranged in the above order along the axial direction S1.

  The solid part 28 is provided in order to ensure sufficient bonding strength with the blade part 40. Specifically, the solid portion 28 is provided as a portion clogged with a metal material. That is, the solid portion 28 is provided as a portion where no hole is formed. The solid part 28 is continuous with the one end part 23. The solid part 28 is formed in a columnar shape extending in the axial direction S1. The solid part 28 is continuous with the cylindrical part 29.

  The cylindrical portion 29 is disposed so as to face the roller 10 (see FIG. 1) in the processing chamber 2. The distance between the container 101 on the roller 10 and the cylindrical portion 29 is, for example, about 10 cm in the vertical direction. The cylindrical portion 29 is provided as a hollow portion for reducing thermal stress generated in the blade portion 40.

  The cylindrical portion 29 has a hole 30 extending in the axial direction S1. The hole 30 is open to one end surface 29a of the cylindrical portion 29, that is, one end surface of the shaft portion 20, and extends from the one end surface 29a toward the solid portion 28 in the other S3 in the axial direction S1. . The hole 30 forms a cylindrical space. The other end portion of the hole 30 is formed in a tapered shape, and the diameter is set smaller as the portion is closer to the solid portion 28. The bottom surface 30a of the hole 30 extends so as to be orthogonal to the axial direction S1.

  The thickness T1 of the cylindrical portion 29 is defined as a distance between the outer peripheral surface 29b of the cylindrical portion 29 and the inner peripheral surface 29c. In the present embodiment, the thickness T1 indicates the minimum distance between the outer peripheral surface 29b and the inner peripheral surface 29c. Further, the thickness T1 indicates an interval between the outer peripheral surface 29b and the inner peripheral surface 29c along the radial direction R1. In the present embodiment, the thickness T1 of the cylindrical portion 29 is set to about 15 mm. Further, the outer diameter d1 of the cylindrical portion 29 is set to about 100 mm. The outer diameter d1 is the diameter of the outer peripheral surface 29b. The inner diameter d2 of the cylindrical portion 29 (the diameter of the hole portion 30) is set to about 70 mm. The inner diameter d2 is the diameter of the inner peripheral surface 29c.

  In the present embodiment, the length le1 of the cylindrical portion 29 is set to be greater than the length le2 of the solid portion 28 with respect to the axial direction S1. Regarding the axial direction S1, the length le1 of the cylindrical portion 29 may be the same as the length le2 of the solid portion 28 or may be smaller than the length le2 of the solid portion 28. The blade fixing part 22 having the above configuration fixes a plurality of blade parts 40.

  In this embodiment, the blade | wing part 40 is provided in order to generate the wind which goes to the outward of radial direction R1. A plurality of blade portions 40 are provided at equal intervals in the circumferential direction C1 and extend radially from the blade fixing portion 22. In the present embodiment, four blade portions 40 are provided. The configuration of these blade portions 40 is the same.

  The blade portion 40 is formed in a plate shape, extends along one direction of the radial direction R1, and extends in the axial direction S1. The one direction in the radial direction R1 is defined as the longitudinal direction L1 of the blade portion 40. In the longitudinal direction L1, the distance between the tip of the blade portion 40 and the central axis B1 of the stirring fan 7, that is, the radius of the stirring fan 7 is set to about 250 mm. The thickness direction of the blade portion 40 substantially coincides with the circumferential direction C1.

  The thickness of the blade portion 40 is set to be the largest at the root portion 41 of the blade portion 40. The thickness of the intermediate portion 42 of the blade portion 40 in the longitudinal direction L1 is set to be equal to or less than the thickness of the root portion 41. The thickness of the blade portion 40 is set so as to become smaller as the tip portion 43 of the blade portion 40 is approached.

  The root portion 41 of the blade portion 40 is continuous with the blade fixing portion 22. The other end 45 of the root portion 41 in the axial direction S <b> 1 is fixed to the outer peripheral portion of the solid portion 28. An intermediate portion and one end portion 44 of the root portion 41 in the axial direction S <b> 1 are fixed to the outer peripheral portion of the cylindrical portion 29.

  One side surface 46 and the other side surface 47 of the blade portion 40 are curved at the root portion 41 and are less likely to cause stress concentration. On the other hand, the one side surface 46 and the other side surface 47 are planar at the intermediate portion 42 and the tip portion 43. In the one side face 46 and the other side face 47, a portion that transitions from a curved shape to a planar shape is a boundary portion 50 between the root portion 41 and the intermediate portion 42. The boundary part 50 is also the tip of the root part 41. Further, on one side surface 46 and the other side surface 47, projections 48 and 49 are provided at the tip end portion 43.

  With reference to FIG. 6, in the present embodiment, the thickness T <b> 2 of the root portion 41 of the blade portion 40 refers to the thickness of the boundary portion 50. That is, the thickness T2 of the root portion refers to the thickness of the tip of the root portion 41. In other words, the thickness T2 of the base portion 41 refers to the thickness of the portion of the blade portion 40 where the thermal stress is maximum.

  In the present embodiment, the thickness T <b> 1 of the cylindrical portion 29 is set in a range of 75% to 125% of the thickness T <b> 2 of the root portion 41. By setting the thickness T1 of the cylindrical portion 29 to 100% (T1 = T2) of the thickness T2 of the root portion 41, the temperature difference between the cylindrical portion 29 and the root portion 41 can be significantly reduced. In other words, the heat capacity of a portion of the cylindrical portion 29 that continues to the root portion 41 and the heat capacity of the root portion 41 can be made extremely close to each other.

  Further, when the thickness T1 of the cylindrical portion 29 is set to 75% of the thickness T2 of the root portion 41, the thickness is substantially the same as when T1 = T2, and the same effect as described above can be exhibited. In addition, said lower limit is corresponded to the lower limit of the dimensional tolerance of thickness T1 at the time of manufacturing the stirring fan 7. FIG. That is, at the time of manufacturing the stirring fan 7, 75% of the thickness T2 of the root portion 41 is the lower limit allowable value of the thickness T1 of the cylindrical portion 29.

  Further, when the thickness T1 of the cylindrical portion 29 is set to 125% of the thickness of the root portion 41, the thickness is substantially the same as when T1 = T2, and the same effect as described above can be exhibited. The upper limit value corresponds to the upper limit value of the dimensional tolerance of the thickness T1 when the stirring fan 7 is manufactured. That is, at the time of manufacturing the stirring fan 7, 125% of the thickness T <b> 2 of the root portion 41 is the upper limit allowable value of the thickness T <b> 1 of the cylindrical portion 29.

  With reference to FIGS. 2 to 5, the length of the blade portion 40 in the axial direction S <b> 1 is reduced continuously or stepwise as the tip portion 43 of the blade portion 40 is advanced. Specifically, the blade part 40 has one edge part 51 and another edge part 52. The one edge portion 51 refers to an edge portion on one end side of the blade portion 40 in the axial direction S1. Moreover, the other edge part 52 says the edge part of the other end side of the blade | wing part 40 in the axial direction S1.

  In this embodiment, the one edge portion 51 of the blade portion 40 is formed in a planar shape extending in a direction orthogonal to the axial direction S1. The one edge portion 51 is continuous with the one end surface 29a of the cylindrical portion 29, and is arranged on the same plane as the one end surface 29a.

  The other edge part 52 is spaced apart from the one edge part 51 in the axial direction S1. The other edge 52 is an edge including a curved surface portion and a planar portion. The other edge portion 52 includes a first portion 53, a second portion 54, a third portion 55, a fourth portion 56, and a fifth portion 57.

  The first portion 53 is provided as the other edge portion of the root portion 41. The first portion 53 is formed in a circular arc surface shape. The center of curvature E <b> 1 of the first portion 53 is located on the other side S <b> 3 in the axial direction S <b> 1 with respect to the first portion 53. The first portion 53 advances toward one side S <b> 2 in the axial direction S <b> 1 as it moves away from the shaft portion 20, and extends so as to approach the one edge portion 51. The first portion 53 is a portion having the shortest distance from the hole portion 30 of the cylindrical portion 29 in the other edge portion 52.

  In the present embodiment, the shortest distance T3 between the first portion 53 (the other edge portion 52) and the hole 30 is set to be equal to or larger than the radius r1 of the main spindle body 24 of the main spindle portion 21 adjacent to the blade fixing portion 22. (T3 ≧ r1). The main shaft body 24 is a portion having the smallest shaft diameter between the bearing 27 on the one S2 side in the axial direction S1 and the blade portion 40. In the present embodiment, the radius r1 of the main spindle body 24 is set to about 30 mm. Thus, the shortest distance T3 is set to be equal to or larger than the radius r1 of the main spindle body 24 in the main spindle portion 21 adjacent to the blade fixing portion 22 in the shaft portion 20.

  In the present embodiment, the shortest distance T3 is set to the same value as the radius r1 (T3 = r1). The depth and shape of the hole 30 and the diameter of the bottom surface 30a of the hole 30 are defined so that the shortest distance T3 = radius r1 is realized. The first portion 53 is smoothly continuous with the outer peripheral surface of the one end portion 23 of the main shaft portion 21. Further, the first portion 53 is smoothly continuous with the second portion 54.

  The second portion 54 is provided as a part of the other edge portion in the intermediate portion 42 of the blade portion 40. The second portion 54 is formed in a circular arc shape. The center of curvature of the second portion 54 coincides with the center of curvature E1 of the first portion 53. The second portion 54 advances toward one side S <b> 2 in the axial direction S <b> 1 as it moves away from the shaft portion 20, and extends so as to approach the one edge portion 51. The second portion 54 is smoothly continuous with the third portion 55.

  The third portion 55 is provided as a part of the other edge portion in the intermediate portion 42 of the blade portion 40. The third portion 55 extends in parallel with the one edge portion 51. In the present embodiment, in the longitudinal direction L1, the length of the third portion 55 is the length of the first portion 53, the length of the second portion 54, the length of the fourth portion 56, and the length of the fifth portion 57. It is set larger than any of the above. The third portion 55 is continuous with the fourth portion 56.

  The fourth portion 56 is provided as a part of the other edge portion 52 in the intermediate portion 42 of the blade portion 40. The fourth portion 56 extends so as to be inclined with respect to the one edge portion 52. The fourth portion 56 is inclined so that the distance from the one edge portion 51 becomes shorter as the tip portion 43 of the blade portion 40 is approached. One edge of the intermediate portion 42 is formed by the second portion 54, the third portion 55, and the fourth portion 56. The fourth portion 56 is continuous with the fifth portion 57.

  The fifth portion 57 is provided as the other edge portion of the tip end portion 43 of the blade portion 40. The fifth portion 57 is formed on a plane aligned with the fourth portion 56 on the same plane.

  During the heat treatment by the heat treatment apparatus 1, the stress generated in the stirring fan 7 tends to be greatest at the one end portion 44 and the other end portion 45 of the root portion 41 of the blade portion 40.

  As described above, according to the heat treatment apparatus 1, the cylindrical portion 29 is formed in the blade portion fixing portion 22. Thereby, the heat capacity of the portion of the cylindrical portion 29 that is continuous with the root portion 41 of the blade portion 40 becomes a value close to the heat capacity of the root portion 41. For example, even when cool air from the article 100 to be processed comes into contact with the stirring fan 7 in a high temperature state, the difference between the temperature of the cylindrical portion 29 and the temperature of the root portion 41 of the blade portion 40 can be further reduced. That is, the temperature gradient between the cylindrical portion 29 and the root portion 41 of the blade portion 40 can be further reduced. Therefore, the thermal stress generated in the root part 41 of the blade part 40 can be reduced. In addition, the cylindrical portion 29 has an inner peripheral surface 29c in addition to the outer peripheral surface 29b, and has a large surface area. That is, the cylindrical portion 29 can ensure a large surface area, like the blade portion 40. For this reason, when the cold air from the article 100 is in contact with the stirring fan 7 in the high temperature state, the speed at which the cylindrical portion 29 is cooled can be close to the speed at which the root portion 41 is cooled. Therefore, the temperature gradient between the cylindrical portion 29 and the root portion 41 of the blade portion 40 can be further reduced. In particular, when the thickness T1 of the cylindrical portion 29 is set to 100% of the thickness T2 of the root portion 41, the above-described temperature gradient can be remarkably reduced. Thereby, since the thermal stress which arises in the root part 41 of the blade | wing part 40 can be made very small, the lifetime of the fan 7 for stirring can be made longer. Further, the range of the thickness T1 of the cylindrical portion 29 is set between the aforementioned lower limit and the upper limit. Thereby, the effect substantially the same as the case where the thickness T1 of the cylindrical part 29 is made the same as the thickness T2 of the root part 41 can be exhibited.

  Moreover, since the cylindrical portion 29 is hollow, it is lightweight. Therefore, the stirring fan 7 can be reduced in weight. Thereby, the load to the bearings 27 and 27 that support the stirring fan 7 can be reduced. Therefore, the lifetime of the heat treatment apparatus 1 as a whole including the stirring fan 7 can be extended.

  Therefore, the life of the stirring fan 7 of the heat treatment apparatus 1 can be extended and weight reduction can be achieved.

  Further, as a result of the longer life of the stirring fan 7, the number of times of replacing the stirring fan 7 can be reduced. For this reason, the frequency which stops the heat processing apparatus 1 can be decreased more. As a result, the cost for the operation of the heat treatment apparatus 1 can be further reduced.

  Further, according to the heat treatment apparatus 1, the shortest distance T3 between the other edge portion 52 of the blade portion 40 and the hole portion 30 of the cylindrical portion 29 is set to be equal to or larger than the radius r1 of the main spindle body 24 of the main spindle portion 21. Thereby, the coupling | bonding strength of the blade | wing part 40 and the axial part 20 is fully securable. For this reason, even when the stirring fan 7 rotates at a high speed, the tensile stress generated in the root portion 41 of the blade portion 40 due to the centrifugal force of the blade portion 40 does not need to be excessively increased. Therefore, the allowable rotational speed of the stirring fan 7 can be sufficiently increased. That is, the high-temperature gas in the processing chamber 2 can be sufficiently stirred by the high-speed rotation of the stirring fan 7.

  Moreover, according to the heat processing apparatus 1, the blade | wing fixing | fixed part 22 and the blade | wing part 40 are integrally formed by casting. As described above, the occurrence of cracks can be suppressed in the casting stirring fan 7 in which cracks due to thermal stress are likely to occur.

  Further, according to the heat treatment apparatus 1, the stirring fan 7 is arranged in a posture in which the cylindrical portion 29 and the roller 10 face each other. According to this configuration, the cold air from the workpiece 100 received by the roller 10 is mainly transmitted to the cylindrical portion 29 and the root portion 41 of the blade portion 40 in the stirring fan 7. Even if the stirring fan 7 is in a high temperature state, the temperature gradient generated between the cylindrical portion 29 and the blade portion 40 due to the cold air described above may be small. Therefore, even when the temperature difference between the stirring fan 7 and the workpiece 100 is large, the thermal stress generated in the root portion 41 of the blade portion 40 can be reduced. Therefore, the life of the stirring fan 7 can be further extended.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment. The present invention can be variously modified as long as it is described in the claims.

  (1) In the above-mentioned embodiment, although the dimension of each part of the stirring fan 7 was illustrated suitably, it does not need to be this way. The dimension of each part of the stirring fan 7 is not limited to the illustrated value.

  (2) In the embodiment described above, the hole 30 of the cylindrical portion 29 of the stirring fan 7 is formed in a cylindrical shape, but this need not be the case. The shape of the hole 30 is not particularly limited. For example, the shape of the hole 30 may be conical.

  (3) Moreover, the shape of the blade | wing part 40 is not specifically limited. For example, the one edge part 51 of the blade | wing part 40 may contain the part formed in the curve shape. Further, the other edge portion 52 of the blade portion 40 may be a single plane.

  (4) Moreover, in the above-mentioned embodiment, the shortest distance T3 between the other edge part 52 of the blade | wing part 40 and the hole 30 of the cylindrical part 29 is the form which is more than the radius r1 of the main spindle main body 24 of the main spindle part 21. Although described in the example, this need not be the case. For example, the shortest distance T3 may be less than the radius r1. Further, the shortest distance T3 may be set to be equal to or larger than the radius of one end of the solid portion 28 or the radius of the other end of the solid portion 28.

  (5) Moreover, although the above-mentioned embodiment demonstrated the form which integrally molds the whole stirring fan 7 by casting, it does not need to be this way. For example, as shown in FIG. 7, the blade portion 40A and the blade fixing portion 22A may be formed as separate members, and the blade portion 40A and the blade fixing portion 22A may be integrally formed by welding. In this case, the welded portion 60 connects the base portion 41A of the blade portion 40A and the outer peripheral surface of the blade fixing portion 22A. In this case, generation of cracks can be suppressed in the stirring fan 7A having the welded portion 60 where cracks due to thermal stress are likely to occur.

  (6) In addition, the manufacturing method of the stirring fan 7 is not specifically limited. For example, the stirring fan 7 may be formed by cutting a metal lump or may be formed by forging.

  (7) In the above-described embodiment, the stirring fan 7 is described as an example of a centrifugal fan, but this need not be the case. For example, the stirring fan 7 may be an axial fan. The axial fan has a twisted blade portion and can blow air toward the axial direction of the axial fan.

  (8) In the above-described embodiment, the stirring fan 7 has been described as an example in which the stirring fan 7 is disposed above the workpiece 100. However, this need not be the case. For example, the stirring fan 7 may be disposed on the side of the article to be processed 100 or below. Further, the direction of the stirring fan 7 is not particularly limited.

  (9) In the present embodiment, the heat treatment apparatus 1 is described as an example in which the heat treatment apparatus 1 is a batch-type heat treatment apparatus, but this need not be the case. The present invention can be used as a stirring fan for a continuous heat treatment apparatus. In the case of a continuous heat treatment apparatus, a plurality of stirring fans are arranged along the transport direction.

  (10) Moreover, the heat treatment apparatus 1 may perform nitriding treatment on the workpiece 100. In this case, the heater 6 heats the gas in the processing chamber 2 to 500 ° C. or higher.

[Production of Examples]
The example shown in FIG. 8 was produced by modeling a stirring fan having the same shape as the stirring fan 7 shown in FIGS. 2 to 6 of the above embodiment on a computer. That is, in the embodiment, the outer diameter, the inner diameter (the diameter of the hole), the thickness of the cylindrical portion, and the thickness of the root portion of the blade portion are set to be the same as the corresponding values of the stirring fan 7. ing.

[Production of Comparative Example]
A comparative example shown in FIG. 8 was produced by modeling on a computer a stirring fan having the same configuration as the example except that all of the blade fixing portions were formed as solid portions. That is, the comparative example does not have a cylindrical portion.

[Experimental conditions]
About the Example, the computer simulation using a finite element method was performed on the conditions shown below.
Condition: Assuming a case where an article to be treated at 25 ° C. is placed directly below the blade fixing portion while the blade fixing portion is heated to 930 ° C. The rotational speed of the example is constant at 1050 rpm. And the temperature and stress of each part of an Example in 3 minutes after a to-be-processed product was installed were calculated. In addition, the stress in a present Example is Mises stress.

  Also for the comparative example, the temperature and stress of each part of the comparative example were calculated under the same conditions as described above.

[Calculation result]
The results are shown in FIGS. 9, 10A and 10B. 8 and 9, in the comparative example, the heat capacity of the blade fixing portion was large, and the central portion of the blade fixing portion was the hottest among the blade fixing portions. The temperature difference between the blade fixing portion and the root portion of the blade portion reached about 50 ° C. at the maximum. On the other hand, in the Example, the bottom part of the hole part was the hottest temperature in the blade fixing part. However, as a result of the small heat capacity of the cylindrical portion of the blade fixing portion, the temperature difference between the blade fixing portion and the root portion of the blade portion was only about 10 ° C. at the maximum. As described above, in the examples, it was proved that the temperature gradient can be remarkably reduced even when the temperature change occurs.

  Regarding the stress, two portions where the stress is greatest are extracted for each of the example and the comparative example, and the results are described. Specifically, for each of the example and the comparative example, the stress at one end and the other end of the root portion of the blade portion will be described.

  With reference to FIG. 8 and FIG. 10A, the stress at one end portion of the root portion in the blade portion is approximately 0.73 in the embodiment, where the numerical value in the comparative example is 1. Therefore, it was proved that the stress at one end portion of the root portion in the example was reduced by about 30% as compared with the stress at one end portion of the root portion in the comparative example.

  8 and 10B, the stress at the other end portion of the root portion in the blade portion is about 0.73 in the embodiment when the numerical value in the comparative example is 1. Therefore, it was demonstrated that the stress at the other end portion of the root portion in the example was reduced by about 30% than the stress at the other end portion of the root portion in the comparative example. Therefore, the maximum value of the stress in the example is only about 70% of the maximum value of the stress in the comparative example. Therefore, it was demonstrated that the example can exhibit an excellent stress reduction effect.

  That is, in the examples, it was proved that the internal stress can be remarkably reduced even when a temperature change occurs during rotation.

  The present invention can be widely applied as a stirring fan for a heat treatment apparatus and a heat treatment apparatus.

DESCRIPTION OF SYMBOLS 1 Heat processing apparatus 2 Processing chamber 7, 7A Stirring fan 10 Roller (receiving part)
20 Shaft portion 22, 22A Blade fixing portion 24 Main shaft body (part of shaft portion adjacent to blade fixing portion)
29 Cylindrical portion 29a One end surface of the cylindrical portion (one end surface of the shaft portion)
30 Hole portion 40, 40A Blade portion 41, 41A Root portion 51 One edge portion 52 Other edge portion 100 Product to be processed r1 Radius S1 Axial direction T1 Cylindrical portion thickness T2 Root portion thickness T3 Shortest distance

Claims (5)

The shaft,
A plurality of blade portions extending radially from the shaft portion,
The shaft portion includes a blade fixing portion that fixes each of the blade portions,
The blade fixing portion has a cylindrical portion extending in the axial direction of the shaft portion,
The hole of the cylindrical part is open to one end surface of the shaft part,
Each of the blade portions has a root portion continuous to the cylindrical portion,
The thickness of the said cylindrical part is set to the range of 75%-125% of the thickness of the said base part, The stirring fan for heat processing apparatuses characterized by the above-mentioned. A stirring fan for the heat treatment apparatus according to claim 1,
Each of the blade portions has one edge continuous to the one end surface of the shaft portion, and the other edge portion spaced from the one edge portion in the axial direction.
The shortest distance between the other edge portion and the hole portion is set to be equal to or greater than the radius of the shaft portion adjacent to the blade fixing portion. A stirring fan for the heat treatment apparatus according to claim 1 or 2,
The stirring fan for a heat treatment apparatus, wherein the blade fixing portion and each blade portion are integrally formed by casting or welding. A treatment chamber for heat treating the article to be treated;
The stirring fan according to any one of claims 1 to 3, which is disposed in the processing chamber,
A heat treatment apparatus comprising: The heat treatment apparatus according to claim 4,
Further provided with a receiving portion disposed in the processing chamber for receiving an object to be processed;
The heat treatment apparatus, wherein the stirring fan is arranged in a posture in which the cylindrical portion and the receiving portion face each other.

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