JP2002147961A - Heat treatment furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment furnace capable of improving productivity by improving the cooling efficiency of a heat treatment material. SOLUTION: The heat treatment furnace comprises at least a furnace body 3, a heater 5 situated at the internal part of the furnace body 3, and a muffle M situated on the inside of the heater 5 and containing a material 7 to be treated. The heat treatment furnace has structure when a heating chamber K is cooled, the muffle M is exposed with atmosphere in the heating chamber K held.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment furnace mainly used for heat treatment such as degreasing or firing a ceramic electronic component. More specifically, the present invention relates to at least a furnace body and a furnace body. The present invention relates to a heat treatment furnace including a heater disposed therein and a muffle that is disposed inside the heater and forms a heating chamber in which a workpiece is stored.

[0002]

2. Description of the Related Art Conventionally, as this kind of heat treatment furnace, for example, a heat treatment furnace having a structure disclosed in Japanese Patent Application Laid-Open No. 10-141859 is known.

In this structure, the muffle is kept airtight in order to maintain the atmosphere in the muffle in a predetermined state when the ceramic electronic component is heat-treated, and the atmosphere gas can be supplied into the muffle. , A gas supply pipe is connected to the muffle. Thereby, heat treatment can be performed in a state where the heating chamber is maintained at a predetermined atmosphere.

[0004]

By the way, after the heat treatment step is completed, there is a cooling step of cooling the object and the muffle to, for example, room temperature. For this cooling, the muffle is left inside the furnace body. A possible method is to take out the processed material from the muffle and expose it to the outside air.

However, when the object to be processed is exposed to the outside air at a high temperature as described above, the surface of the object to be processed unduly reacts with the outside air, and there is a possibility that the object to be processed is deteriorated. Therefore,
Although it is desirable to cool in a predetermined atmosphere, there is a disadvantage that the processed material cannot be kept at a high quality because the processed material comes into contact with the outside air.

Therefore, in order to avoid this point, conventionally, the muffle was naturally cooled while leaving the muffle inside the furnace so that the muffle could be cooled while maintaining a predetermined atmosphere in an airtight state. However, in the case of such natural cooling, since the muffle remains in the furnace of the heat insulation structure, it takes a long time for the object to be cooled to the desired temperature, and the productivity is reduced. There is a problem.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a heat treatment furnace capable of improving the cooling efficiency of a heat treatment product and improving productivity.

[0008]

According to a first aspect of the present invention, there is provided a heat treatment furnace comprising at least a furnace body, a heater disposed inside the furnace body, and a processing object disposed inside the heater. A heat treatment furnace including a muffle forming a heating chamber to be housed therein, wherein the muffle is configured to be exposed to outside air while maintaining an atmosphere in the heating chamber when cooling the heating chamber. Is a characteristic configuration.

According to the configuration of the first aspect of the present invention, the muffle is maintained in the heating chamber of the muffle while the atmosphere during the heat treatment is performed, and the object to be processed is stored in the heating chamber. The heating chamber can be cooled in a short period of time because the heating chamber can be cooled in a short time from the state of being confined inside, and the object to be processed is not directly exposed to the outside air during cooling. Deterioration of the processing object due to contact with outside air can be avoided, and the processing object can be maintained at high quality. Further, since it is not necessary to provide a special cooling device for cooling the muffle without exposing it to the outside air while being housed in the furnace main body, the structure of the entire heat treatment furnace can be simplified.

A heat treatment furnace according to a second aspect of the present invention is the heat treatment furnace according to the first aspect, wherein the furnace main body is configured to be separable into a plurality of furnace body portions. The muffle can be exposed to the outside air by separating one or more of the furnace body parts from other furnace body parts.

According to the configuration of the second aspect of the present invention, the muffle is exposed to the outside air by changing the furnace main body configured to be separable into a plurality of furnace bodies from one or more of the furnace body parts. Because of the separation, the heat insulation around the muffle is released, thereby exposing the muffle to the outside air, thereby facilitating the cooling of the heating chamber, that is, the muffle and the workpiece, and thereby, The cooling process can be shortened.

According to a third aspect of the present invention, there is provided a heat treatment furnace according to the second aspect, wherein the furnace main body has a cylindrical shape and a bottom opening, and a bottom opening of the furnace body. And a hearth portion which is located on the side of the heating chamber and supports the object to be processed in the heating chamber.

According to the third aspect of the present invention, since the furnace body constituting the heat insulating structure includes the furnace body and the furnace floor supporting the workpiece in the heating chamber, the furnace body during firing is provided. When the furnace body is made to be integral or almost integral, the heat insulation of the furnace body becomes high and the furnace body and the hearth can be separated. Thus, the heating chamber can be exposed to the outside air while supporting the object to be processed, thereby achieving cooling.

According to a fourth aspect of the present invention, in the heat treatment furnace according to the third aspect, when cooling the heating chamber, the muffle is formed by lowering the hearth relative to the furnace body. It is characterized in that it can be exposed to outside air outside the furnace.

According to the fourth aspect of the present invention, the exposure of the muffle to the outside air is realized by lowering the hearth relative to the furnace body, so that the heat insulation around the muffle is achieved. The structure is released, thereby exposing the muffle to the outside air, thereby facilitating the cooling of the heating chamber, that is, the muffle and the workpiece, thereby shortening the cooling process. Further, since a furnace body or the like is separated into a plurality of parts and a muffle is exposed to the outside air, a special structure for separating and connecting the furnace body is not required, so that the structure becomes simple.

A heat treatment furnace according to a fifth aspect of the present invention is the heat treatment furnace according to any one of the first to fourth aspects, wherein the muffle having an internal space as the heating chamber has a cylindrical shape with an open bottom. And a base portion which is a separate structure from the tubular portion and is formed in a flange shape radially outward along the bottom opening peripheral edge, and a lower end opening of the tubular portion and the base portion. It is characterized in that an annular packing is interposed between them.

According to the fifth aspect of the present invention, it is known that the muffle, particularly when made of metal, has a tubular portion and a base portion integrated in advance by welding to maintain an airtight state. However, since the stress due to the load of the cylindrical portion tends to concentrate at the welded portion, there is a problem that the welded portion is easily cracked and the durability is reduced, Because it has a structure that is separated into a part and a base part, and because the cylindrical part and the base part are crimped via packing, the cylindrical part and the base part are separated. regardless of,
The airtightness inside the muffle can be maintained.

According to a sixth aspect of the present invention, in the heat treatment furnace according to the fifth aspect, the packing is pressed toward the base portion by a cylindrical portion of the muffle or a pressing member integrated therewith. The feature configuration is that it is possible.

According to the structure of the sixth aspect of the present invention, since the packing can be pressed toward the base portion by the downward load due to the weight of the cylindrical portion or the pressing member, the cylindrical portion of the packing can be pressed by the pressing force. Adhesion to the base and the base portion is enhanced, and the airtightness in the muffle can be increased.

According to a seventh aspect of the present invention, in the heat treatment furnace according to the sixth aspect, a pressing mechanism for pressing the cylindrical portion of the muffle or a pressing member integrated therewith against the packing. Having a characteristic configuration.

According to the seventh aspect of the present invention, when the packing is pressed by the pressing mechanism, the posture of the tubular portion is maintained as compared with the case where the packing is pressed only by the weight of the tubular portion of the muffle. And the like, and the airtightness in the muffle can be sufficiently increased.

The heat treatment furnace according to claim 8 of the present invention is the heat treatment furnace according to claim 7, wherein the pressing mechanism includes a pressing action portion for pressing the packing, and a power transmission portion connected to the pressing action portion via a power transmission portion. And a driving device for applying a pressing force, and the driving device is arranged to be spaced outward from the pressed portion.

According to the eighth aspect of the present invention, since the driving device is disposed outwardly away from the pressing portion, that is, the peripheral portion of the lower end of the cylindrical portion of the muffle, thermal influence from the muffle is provided. Is hardly received by the driving device, and a favorable thermal environment for the driving device, specifically, an actuator such as an air cylinder or a hydraulic cylinder can be maintained.

According to a ninth aspect of the present invention, in the heat treatment furnace according to the eighth aspect, the power transmission portion is pivotally supported at an intermediate position so that both ends thereof are reciprocally vertically oscillated. An upward force is input from the driving device to one end of the moving arm, and a downward force is applied to the other end of the moving arm.

According to the configuration of the ninth aspect of the present invention, the airtightness of the muffle can be kept good by a simple configuration using the swing arm.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 6 is a view showing an example of a heat treatment furnace according to the present invention. This heat treatment furnace is a heat treatment furnace for performing a baking of a ceramic electronic component such as a piezoelectric element or a magnetic element, or a heat treatment for performing a degreasing treatment or the like.

As shown in FIG. 6, the heat treatment furnace comprises a furnace body 1 composed of a heat insulator 1 made of a ceramic material and a hearth 2 made of a heat insulator. ,
A cylindrical portion 4 of muffle М is arranged in a furnace chamber L to be described later in the furnace body 3, and high heat is applied to a space between the cylindrical portion 4 of muffle と and the inner wall of the furnace body 1 in the furnace chamber L. A heater 5 is provided as a heat source to be generated.

As shown in FIG. 6, the furnace 1 is formed in a cylindrical shape having a ceiling, and the bottom of the furnace 1 is open.
The internal space of the cylindrical structure in the furnace body 1 is a furnace chamber L in which the cylindrical portion 4 of the muffle М is disposed, and is formed of a heat-resistant metal (for example, stainless steel, Inconel 601 or the like). The part 4 is arranged so as to be concentric with the furnace chamber L. The cylindrical portion 4 has a ceiling 4a and has an opening at the bottom. The lower end of the cylindrical portion 4 extends below the opening at the bottom of the furnace body 1 and has a lower end. Are placed on a base 6 described later.

The mounting table 2A of the hearth 2 which can be moved up and down is inserted into the opening at the bottom of the cylindrical portion 4. That is, the hearth 2
Has a disk-shaped base 2B and a mounting table portion 2A formed in a central portion thereof so as to protrude upward in a columnar shape, and is integrally formed of a heat insulating material, and has an outer diameter substantially equal to the inner diameter of the cylindrical portion 4. The mounting table portion 2A rises in the hearth 2 so that the cylindrical portion 4
It is designed to get inside. On the mounting table 2A,
A shelf 8 made of a heat-resistant material is provided for storing and deploying a large number of ceramic electronic components as objects to be processed 7 in a state suitable for heat treatment.

The hearth 2 is configured to be able to be lifted and lowered and stopped up and down while being supported by a lifting device (not shown). It is configured to be driven to rotate around P. Therefore, as shown in FIG. 7, the furnace floor 2 is lowered to a predetermined position below the place where the furnace body 1 and the cylindrical portion 4 are provided, and the shelf 8 and the workpiece 7 face the outside. In this case, the work to be processed 7 can be taken in and out of the shelf 8. On the other hand, in a state where the hearth 2 is raised to a predetermined position so that the mounting table portion 2A enters the inside of the tubular portion 4, the space surrounding the tubular portion 4 and the hearth 2 is sealed (details will be described later). In this state, the cylindrical portion 4 is heated by the radiant heat from the heater 5, and the object to be processed 7 is heated in the heating chamber K, which is a closed space in the cylindrical portion 4. Can be performed.

Further, in the space between the cylindrical portion 4 and the inner wall of the furnace body 1, a plurality of rod-shaped heaters 5 are arranged at predetermined intervals along the circumference concentric with the cylindrical portion 4. Are arranged. These heaters 5 are supplied with electric power from the outside of the furnace body 1 and serve as heat sources during a heating process. Further, a gas supply pipe 10 and an exhaust pipe 11 are connected to a ceiling 4a of the tubular portion 4 in an airtight state. A gas for keeping the heating chamber 4 in an atmosphere suitable for the degreasing step and the main firing step, for example, an atmosphere gas such as a nitrogen gas or an argon gas is supplied into the heating chamber 4 from a gas supply source (not shown) through the gas supply pipe 10. You.

The muffle マ ッ is, as described above, a ceiling 4a.
And a base portion 6 having a cylindrical shape. The base portion 6 supports the tubular portion 4 in a mounted state, and the base portion 6 is further fixedly supported by a fixed support portion 12 and also moves the hearth portion 2 to an elevating device. The lower side is closed by a disk-shaped support base 13 for supporting the camera. That is, as shown in FIGS. 6 to 8, the base portion 6 includes a disc-shaped member 15 which penetrates vertically and has a hole 14 having substantially the same diameter as the outer diameter of the cylindrical portion 4. And a cylindrical member 16 integrally welded to the lower surface of the cylindrical member 15, and a sealing member 17 made of a ring-shaped silicon sponge provided on the By closely adhering to the lower edge of the body 16, the space surrounded by the base 6, the support 13 and the like is closed in a closed state.

The cylindrical portion 4 of the muffle М is provided with a heat-resistant packing 18 (for example, a silicone resin packing, a sheet-shaped ceramic packing, a carbon packing, or the like) formed in a ring shape. Are mounted and supported on the upper surface of the disc-shaped member 15. More specifically, a ring-shaped flange portion 19 is mounted on the edge portion which is radially outwardly expanded at the lower end of the cylindrical portion 4 over the entire periphery thereof. Is welded to the rim. The lower edge portion of the cylindrical portion 4 is placed on the packing 18 over the entire circumference. The packing 18 is provided in the hole 14 in the disc-shaped member 15.
Are provided in a ring shape along the edge of the. In this way, the cylindrical portion 4 is supported by the base 6 via the packing 18, and the base 6 is supported by the support base 1 via the seal member 17.
By being placed and supported on the heating chamber 3, the airtightness of the space in which the heating chamber 4 and the hearth 2 are arranged is maintained. Here, the one in which the lower end edge portion of the cylindrical portion 4 directly contacts and presses the packing 18 has been described above, but a pressing member separate from the cylindrical portion 4, for example, the ring-shaped flange 1.
The packing may be pressed by a member integrated with the cylindrical portion 4 such as 9.

Further, in order to increase the airtightness between the cylindrical portion 4 and the base portion 6, the cylindrical portion 4 is
There is provided a pressing mechanism 20 for pressing the base unit 6 side via the. As shown in FIGS. 6 to 8, the pressing mechanism 20 includes four (two of them are not shown) having an axis P.
Are arranged symmetrically with respect to the center, so that a force for uniformly pressing the cylindrical portion 4 downward in the circumferential direction with respect to the axis P is applied. As shown in FIG. 8, each pressing mechanism 20 includes a swing arm as a power transmission unit supported on a stay 21 integrally provided on the upper surface of the disc-shaped member 15 so as to be swingable about a horizontal axis X. 22 and the ring-shaped flange portion which is supported at a radially inner end of the swing arm 22 along the radial direction with respect to the axis P so as to be able to swing substantially around an axis parallel to the horizontal axis X. A push action portion 23 that applies a pressing force in a contact state with the push-down portion 19 downward from above, and an air cylinder 24 as a drive device that applies a force that pushes up a radially outer end of the swing arm 22 upward. Make up. The rod end of the air cylinder 24 is supported at the radially outer end of the swing arm 22 so as to be able to swing substantially around an axis parallel to the horizontal axis X. The driving device may be constituted by a linear actuator such as a hydraulic cylinder instead of the air cylinder 24. The air cylinder 24 operates the swing arm 22 so as to be able to move up and down around the axis X. The air cylinder 24 cools the object to be processed when the object is subjected to a heat treatment such as a baking process, and after the heat treatment. When performing, in order to increase the airtightness between the cylindrical portion 4 and the base portion 6, a force is applied to lift the outer end of the swing arm 22 upward so as to strongly press the cylindrical portion 4 against the packing 18. I do.

Thus, in the heat treatment step and the cooling step, the pressing action portion 2 on the inner end of the swing arm 22 is provided.
3 maintains the state in which the ring-shaped flange 20 is pressed down with a constant force, and the packing 18, the cylindrical portion 4, and the base portion 6 are maintained.
To increase the airtightness. In the drawing, reference numeral 25 denotes the outer end of the swing arm 22 and the air cylinder 2.
4 and is a floating joint capable of permitting displacement of the rod of the air cylinder 24 in the lateral direction. In the drawing, reference numeral 26 denotes the packing 18.
Is a ring-shaped vertical flange portion erected on the disk-shaped member 15 in order to form a storage space.

As described above, the muffle М is constituted by the cylindrical portion 4 and the base portion 6 so as to obtain an airtight structure because, when the temperature of the muffle 上 が る rises due to the heat treatment, the muffle 筒 becomes cylindrical. The portion 4 is subjected to a force to expand upward, and the entire muffle is lifted. Therefore, stress is applied to the weld between the base portion and the cylindrical portion fixed to the heat treatment furnace main body. This is because there is a possibility that airtightness may not be maintained due to cracks in this portion. For this reason, in the above embodiment, the ring-shaped flange 19 of the cylindrical portion 4 is pressed, but when an upward force is applied to the cylindrical portion 4, the air cylinder 24 is pressed.
Is pushed back, thereby canceling out this upward force. The cylindrical portion 4 of the muffle す る also expands in the radial direction.
Such displacements are offset by the floating joint. As a result, an unnecessary load is not applied to the ring-shaped flange 19.

Next, a structure for rapidly cooling the workpiece 7 and the muffle ７ after the heat treatment will be described. As shown in FIGS. 1 to 5, the furnace body 1 has a structure that can be divided into two parts left and right or front and rear at a dividing boundary F passing through upper and lower through holes for inserting the gas supply pipe 10 and the exhaust pipe 11. ing. Each of the divided furnace portions 1A and 1B constituting the furnace body 1 is provided so as to be able to move toward and away from each other and to be able to move toward and away from the cylindrical portion 4 of the muffle М. Driving means is provided. FIG. 3 shows a plan view of the furnace body 1 at the time of heat treatment, and shows a state in which the divided furnace parts 1A and 1B are integrated. FIG. 2 is a plan view showing the furnace body 1 at the time of cooling the muffle М and, consequently, the object 7 to be processed. The furnace body 1 shows a state where the divided furnace portions 1A and 1B are separated from each other. FIG. 1 is a perspective view schematically showing the furnace body 1 and the like during the cooling.

More specifically, each split furnace part 1A, 1B is
Each is fixed to the machine bases 27A and 27B in a state of being integrally mounted, and a fixed frame W is provided so as to surround the furnace body 1 and the machines 27A and 27B. Each machine stand 27
A and 27B are provided so as to be slidable relative to the floor. As shown in FIG. 4, the electric motor 28 is fixed to the fixed frame W fixed to the floor.
And a pair of screw shafts 29, 2 which are rotationally driven by transmitting the power from the electric motor 28.
Each of 9 has both ends rotatably supported by a fixed frame W. 4 and FIG. 5.
As shown in the drawing (muffles and the like are omitted), screw guide portions 30A, 30 erected on each machine base 27A, 27B.
B is screwed. In each screw shaft 29, the machine base 27A
One side and the other side from the center of the screw shaft 29 so that the screw engagement with the screw guide portion 30A and the screw engagement of the machine base 27B with the screw guide portion 30B are in opposing screw advancing states. The threading direction of the screw thread formed in is formed in the opposite direction. Also, the respective screw shafts 29, 29 have their screw rotation axis directions set to the dividing boundary surfaces F of the respective dividing furnace portions 1A, 1B.
Are arranged at the side of the lower part of each of the divided furnace sections 1A and 1B in a state orthogonal to the above. The power is transmitted to the screw shaft 29 on the side closer to the electric motor 28 by chain transmission, and the power is transmitted from this screw shaft 29 to the other screw shaft 29 via a chain transmission device arranged in the fixed frame W. Like that. Here, the electric motor 28, the screw shaft 2
9, 29, the screw guides 30A and 30B, the chain transmission mechanism and the like constitute a driving means for movement.

With this structure, the two screw shafts 29, 29 are driven to rotate in synchronization. And split furnace part 1
When the A and 1B are separated from each other, an artificial command is given by a switch operation (not shown), the electric motor 28 is driven to rotate forward, and the two screw shafts 29,
29 rotates, and with the rotation, the screw guide portions 30A, 3
Since OBs are operated so as to be separated from each other, the machine bases 27A and 27B are operated so as to be separated from each other, and thus the split furnace portions 1A and 1B are operated so as to be separated from each other. For example, a split furnace part 1A or a split furnace part 1B is operated by a limit switch (not shown) such as a photo sensor.
Is detected at the maximum separation position, and when it is detected that it is at the maximum separation position, the electric motor 28 is controlled to stop automatically. On the other hand, when the split furnace portions 1A and 1B in the open state are united to perform the heat treatment, a start command for starting a closing operation toward the uniting is artificially input, so that the electric motor 28 is driven to rotate in reverse, and the two screw shafts 29, 29 rotate in the opposite direction to the opening when the screw shaft is opened, and the screw guide portion 3
0A and 30B are operated so as to approach each other, so that the machine bases 27A and 27B operate so as to approach each other, and as a result, the split furnace sections 1A and 1B are operated so as to approach each other, and the split furnace sections 1A and 1B are operated. Will be united. The control is performed so that the electric motor 28 is stopped by detecting an overload state of the electric motor 28 due to the merging or detecting the merging state by a limit switch or the like. The drive control of the moving drive device is performed by a control device (not shown), and the divided furnace portions 1A, 1B
The control to separate or unite the two in a separated state is not limited to inputting a start command or a stop command etc. artificially, and is automatically operated by a control device according to completion of a predetermined firing process. It may be possible to start and stop. Further, each heater 5 moves together with being attached to the divided furnace parts 1A, 1B. However, when dividing the divided furnace parts 1A, 1B, the heater 5 is moved to the divided furnace parts 1A, 1B.
You may comprise so that it can leave | separate from 1B.

With the above configuration, the object to be processed 7 is muffled.
When performing the heat treatment in the state of being accommodated in the heating chamber K,
The furnace body 1 is kept in an integrated state, and when the heating process is completed and the workpiece 7 is cooled, the divided furnace portions 1A and 1B are mutually moved by a driving device by an artificial command or the like. Will be separated. Accordingly, the muffle М is exposed to the outside so as to be exposed to the outside air while the heating chamber K is maintained in an airtight state. Therefore, the muffle М is quickly cooled by heat exchange with the outside air.
Therefore, the object 5 can be cooled to, for example, room temperature in a relatively short time, and the cooling step and thus the entire step can be shortened.

In the above embodiment, the structure in which the furnace body is divided into two parts has been described. However, the furnace body may be divided into three or more parts so that the divided furnace parts can be relatively separated from each other.

In the above embodiment, the divided furnace parts are shown to be separated from each other. However, a part of the divided furnace is kept fixed, and only the other parts are separated from the fixed divided furnace so that the muffle is exposed to the outside air. It may be configured to move to the separated side. Also, the manner of movement is not limited to the structure of sliding as in the above embodiment, and for example, a divided furnace part swings relatively to other divided furnace parts around the vertical axis as in a so-called double door. A configuration in which the muffle can be exposed to the outside by allowing it to open and close dynamically may be employed. Further, a crane or a forklift may be used to move the divided furnace part away from other furnace parts. In addition, as a configuration in which the furnace body can be separated, the furnace body may be vertically divided using a horizontal plane as a dividing surface.
As a specific example, it is possible to expose the muffle М to the outside by exposing the muffle М to the outside by separating the ceiling portion of the furnace body from the side wall portion of the furnace body together with the heater or the like or while leaving the heater etc. good.

In the above embodiment, the ring-shaped flange portion 19 is welded to the lower end edge of the cylindrical portion 4 to be integrated with the muffle main body portion by casting or cutting without welding. It may be formed in an integrated state.

In the above embodiment, the structure in which the muffle is provided with the flange-shaped base portion in the cylindrical portion is shown, but a structure without such a flange-shaped portion may be employed.

In the above-described embodiment, the structure in which the cylindrical portion 4 of the muffle is pressed against the base portion 6 by the pressing mechanism 20 has been described. However, the packing is interposed by the own weight of the cylindrical portion without providing a special pressing mechanism. Then, it may be pressed against the base portion.

It is preferable that two or more pressing mechanisms are provided in order to surely press the cylindrical portion of the muffle against the base portion. However, three pressing mechanisms are provided in order to uniformly apply a load to the base portion in the circumferential direction. It is more preferable to make the above.

In the above-described embodiment, the furnace body structure having the hearth portion with respect to the furnace body has been described, but a structure having only the furnace body and no hearth portion may be used. (Another Embodiment) Next, another embodiment will be described with reference to FIG. The description of the same structure as in the above embodiment is omitted, and the same reference numeral is given. As shown in FIG. 9, the furnace body 1 can be raised with respect to the muffle し な が ら while maintaining the airtight state in which the atmosphere gas at the time of firing remains in the heating chamber in the muffle 、. Is exposed to the outside air. Thus, while the inside of the heating chamber K is maintained at a predetermined atmosphere at the time of firing, rapid cooling of the muffle М and, consequently, rapid cooling of the workpiece 7 can be performed. The gas supply pipe 10 and the like are configured so as not to obstruct the rise of the furnace body 1.

In order to allow the muffle to be exposed to the outside air while maintaining the airtight state so that the inside of the muffle is maintained in a predetermined atmosphere, the muffle is lowered with respect to the furnace body or the furnace body is lowered. And the muffle may be simultaneously performed.

[0050]

According to the first aspect of the present invention,
Since the muffle can be exposed to the outside air while keeping the atmosphere during the heat treatment in the muffle, the heating chamber can be cooled in a short time, and the productivity can be improved.
Since the object to be processed is not directly exposed to the outside air during cooling, deterioration of the object to be processed due to contact with the outside air during cooling can be avoided, and high quality can be maintained.

According to the structure of the second aspect of the present invention, the muffle is exposed to the outside air by changing the furnace main body configured to be separable into a plurality of parts from one or more of the furnace body parts from other furnace body parts. Because of the separation, the heat insulation around the muffle is released, thereby exposing the muffle to the outside air, thereby facilitating the cooling of the heating chamber, that is, the muffle and the workpiece, and thereby, The cooling process can be shortened.

According to the third aspect of the present invention, since the furnace main body constituting the heat insulating structure includes the furnace body and the furnace floor supporting the workpiece in the heating chamber, the furnace body at the time of firing is provided. When the furnace body is made to be integral or almost integral, the heat insulation of the furnace body becomes high and the furnace body and the hearth can be separated. Thus, the heating chamber can be exposed to the outside air while supporting the object to be processed, thereby achieving cooling.

According to the structure of the fourth aspect of the present invention, the exposure of the muffle to the outside air is realized by lowering the hearth relative to the furnace body. The structure is released, thereby exposing the muffle to the outside air, thereby facilitating the cooling of the heating chamber, that is, the muffle and the workpiece, thereby shortening the cooling process.

According to the fifth aspect of the present invention, it is known that the muffle, particularly when made of metal, has a tubular portion and a base portion integrated in advance by welding to maintain an airtight state. However, since the stress due to the load of the cylindrical portion tends to concentrate at the welded portion, there is a problem that the welded portion is easily cracked and the durability is reduced, Because it has a structure that is separated into a part and a base part, and because the cylindrical part and the base part are crimped via packing, the cylindrical part and the base part are separated. regardless of,
The airtightness inside the muffle can be maintained.

According to the structure of the sixth aspect of the present invention, the packing can be pressed toward the base portion by the cylindrical portion or the pressing member, so that the pressing force causes the packing to adhere to the cylindrical portion and the base portion. The airtightness inside the muffle can be increased due to the enhanced properties.

According to the configuration of claim 7 of the present invention, when the packing is pressed by the pressing mechanism, the stability of the cylindrical portion is reduced as compared with a case where the packing is pressed only by the weight of the cylindrical portion of the muffle. And airtightness in the muffle can be sufficiently increased.

According to the eighth aspect of the present invention, since the driving device is disposed outwardly away from the pressing portion, that is, the peripheral portion of the lower end of the tubular portion of the muffle, thermal influence from the muffle is provided. Is hardly received by the driving device, and a favorable thermal environment for the driving device, specifically, an actuator such as an air cylinder or a hydraulic cylinder can be maintained.

According to the configuration of the ninth aspect of the present invention, the airtightness of the muffle can be kept good by a simple configuration using the swing arm.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a state in which a furnace body is separated so as to expose a muffle to outside air in one embodiment.

FIG. 2 is a schematic plan view showing a state where a furnace body is separated so as to expose a muffle to outside air in one embodiment.

FIG. 3 is a schematic plan view showing a furnace body and the like during heat treatment in one embodiment.

FIG. 4 is a plan view showing a furnace body in a separated state and a mechanism for separating the furnace body in one embodiment;

FIG. 5 is a side view showing a furnace body in a separated state and a mechanism for separating the furnace body in one embodiment;

FIG. 6 is a longitudinal sectional front view showing a heat treatment furnace apparatus during heating or cooling processing in one embodiment.

FIG. 7 is a longitudinal sectional front view showing the heat treatment furnace apparatus in a state where the hearth is lowered in one embodiment.

FIG. 8 is a longitudinal sectional front view showing a pressing mechanism and the like in one embodiment.

FIG. 9 is a longitudinal sectional view showing a furnace body and the like at the time of heat treatment in another embodiment.

FIG. 10 is a longitudinal sectional view showing a furnace body and the like during a cooling process in another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace body 2 Hearth part 3 Furnace main body 5 Heater 6 Base part 18 Packing 20 Pressing mechanism 22 Swing arm (power transmission part) 23 Pressing action part 24 Drive unit K Heating chamber マ ッ Muffle

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F27D 11/02 F27D 11/02 Z 15/02 15/02 H

Claims (9)

[Claims] 1. A heat treatment furnace including at least a furnace main body, a heater disposed inside the furnace main body, and a muffle arranged inside the heater and constituting a heating chamber for accommodating an object to be processed. A heat treatment furnace having a structure in which, when cooling the heating chamber, the muffle is exposed to outside air while maintaining the atmosphere in the heating chamber. 2. The heat treatment furnace according to claim 1, wherein the furnace main body is configured to be separable into a plurality of furnace body portions, and when cooling the inside of the heating chamber, one or more of the furnace body portions are cooled. A heat treatment furnace, wherein the muffle can be exposed to the outside air by separating the muffle from other furnace body parts. 3. The heat treatment furnace according to claim 2, wherein the furnace main body is cylindrical and has an open bottom, and is located on the bottom opening side of the furnace and is processed in the heating chamber. A furnace floor for supporting an object. 4. The heat treatment furnace according to claim 3, wherein, when cooling the heating chamber, the muffle is exposed to outside air outside the furnace by lowering the hearth relative to the furnace body. And a heat treatment furnace. 5. The heat treatment furnace according to claim 1, wherein the muffle having an internal space as the heating chamber has a cylindrical portion having an open bottom, and is separate from the cylindrical portion. A base portion formed in a flange shape radially outward along the bottom opening peripheral edge, and an annular packing is interposed between the lower end opening of the cylindrical portion and the base portion. A heat treatment furnace. 6. The heat treatment furnace according to claim 5, wherein the packing can be pressed toward the base portion by a cylindrical portion of the muffle or a pressing member integrated therewith. Furnace. 7. The heat treatment furnace according to claim 6, further comprising a pressing mechanism that presses the cylindrical portion of the muffle or a pressing member integrated therewith against the packing. . 8. The heat treatment furnace according to claim 7, wherein the pressing mechanism presses the packing,
A heat treatment furnace comprising: a driving device for applying a pressing force to the pressing action portion via a power transmission portion; and wherein the driving device is disposed outside of the pressing portion. 9. The heat treatment furnace according to claim 8, wherein the power transmission unit is connected to one end of a swing arm pivotally supported at an intermediate point so that both ends swing reciprocally up and down. A heat treatment furnace characterized in that an upward force is input and a downward force is applied to the other end of the pressing portion.