JPH0336492A - Door device of heating furnace - Google Patents

Abstract

PURPOSE:To suppress as far as possible the change of furnace inside atmosphere by putting-in and out of a work by forming a sub-open part having an open area capable of putting-in and out of the work in a main door means while attaching a sub-door means to the main door means. CONSTITUTION:In the case where a work 22 is put on a work mounting stand 21 of a first upper part turntable 17, a cylinder 72 is operated to locate a main door means 25 and a movable support flame 58 as shown in the righthand figure. Next, a cylinder 43 is operated to lower a sub-door means 38. Here, a cylinder 62 is operated to take out a fork 52 on which a work 22 is put so as to insert in a furnace of a heating furnace body 11 from an opening 26. At the time point when the fork 52 is inserted in the lower part of the work mounting stand 21, an air cylinder 61 is operated to lift slightly a support shaft 54 of the other end opposed to the side of a fork 51 of a rotating member 52 as a supporting point. Thereby, since the side of the fork 51 is lowered, the work 22 is put on the work mounting stand 21.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a heating furnace for heat-treating a workpiece, and more particularly, the present invention relates to a heating furnace for heat-treating a workpiece. The present invention relates to a furnace door device that opens and closes when extracting water from the furnace.

[Conventional technology]

For example, Ni-Cr steel, Ni-Cr-No steel, Cr steel, Cr-N.

When making workpieces such as gears, shafts, piston pins, crankshafts, etc. from steel materials, these steel materials are processed by forging, etc., and then heat treatments such as carburizing and diffusion are performed in order to strengthen the metal structure. Carburizing is carried out at a temperature of 880 to 950℃ in the heating furnace.
Carburizing is a gas carburizing method in which a gas containing carbon oxide, methane, and their hydrocarbons, such as natural gas, coal gas, or generator gas, is appropriately diluted and injected into a heating furnace. It is widely used because it has the advantage of being easy to set the concentration and can be hardened immediately after carburizing and diffusion.

By the way, the above-mentioned carburizing and diffusion methods involve holding the workpiece in a tray or basket, inserting the tray through the opening of a batch furnace, performing carburizing, diffusion, and quenching, and then removing it from the opening. has been used since ancient times. Since multiple workpieces are held in trays, baskets, etc., even if appropriate heat is applied to the workpieces held near the top or outer periphery, the workpieces held near the center or bottom of the tray etc. The temperature increase rate of the applied heat is hindered by the trays, jigs, and workpieces held near the top and outer periphery.Therefore, a stirring fan is installed inside the furnace to equalize the temperature inside the furnace. However, the time difference between the top or outer periphery and the center or bottom is unavoidable, resulting in variations in carburization depth. Furthermore, in a batch furnace, not only the workpiece to be processed as described above but also the jigs that support the workpiece are heated to the carburizing temperature or diffusion temperature.
Heating distortion occurs in jigs, etc. In addition, cooling distortion occurs during cooling, so jigs and the like cannot be used for long periods of time and are treated as consumable items. Furthermore, when controlling the atmospheric temperature in the furnace for heat treatment of workpieces, the heat capacity of trays, baskets, jigs, etc. must of course be taken into account, but the heat capacity of the jig itself is usually larger than the workpiece. As a result, the amount of heat required increases, forcing uneconomical operation.

Therefore, the present inventor has developed an invention that was published as Japanese Patent Publication No. 61-544 and patented as Patent No. 1,339,640, and an invention that was published as Japanese Patent Publication No. 62-48152 and patented as Patent No. 1,441,721. In the patented invention, the furnace chamber is made into a cylindrical shape with an upright axis, a plurality of turntables are arranged vertically inside the furnace chamber, a workpiece is placed on these turntables, and each turntable is rotated horizontally. At the same time, we proposed a furnace that heat-treated the workpiece. That is, these furnaces have a cylindrical furnace chamber whose axial direction is upright. Inside this furnace chamber, a plurality of turntables are coaxially arranged so as to be rotatable in the horizontal direction, and a plurality of workpiece mounting tables for holding workpieces are provided at appropriate intervals on the outer periphery of the upper surface of each turntable. There is. At the center of each turntable, there is a circulation fan that rotates at a higher speed than the turntables to equalize the temperature inside the furnace and speed up heat transfer to the workpiece, and diffuser blades are installed concentrically and radially opposite the circulation fan. It is being Furthermore, a workpiece insertion port and a workpiece removal port are provided on the side of the furnace wall, and the workpiece is placed on the mounting table from the workpiece insertion port by the horizontal direction, and the processed workpiece is removed from the workpiece removal port. It is configured to insert and remove a fork. With such a configuration, the entire furnace can be made relatively compact, and a large number of workpieces can be heat-treated continuously. Further, due to the relative rotation of the turntable and the circulation fan, the heated airflow from the heating means is diffused by the diffuser blades, so that heat can be quickly transferred to the workpiece.

[Problem to be solved by the invention]

On the other hand, in the case of such a heating furnace for gas carburizing.

Transferring workpieces to and taking them out of the furnace is done by opening the furnace door or cover that covers the opening that communicates with the furnace wall from the furnace wall, but when taking workpieces in and out, do not prevent outside air from entering the furnace as much as possible. If this occurs, the atmosphere inside the furnace may be damaged and the desired carburization may not be carried out. Especially in a furnace like the above-mentioned patent where multiple turntables are arranged in the furnace,
The opening also needs to be long in the vertical direction, but when placing workpieces on a turntable, for example, first place the workpieces on the upper turntable, then place the workpieces on the lower turntable. It is necessary to take the steps of placing the If the entire opening is opened when loading or unloading a workpiece, gas in the furnace will be lost and outside air will enter the furnace, resulting in deterioration of the working environment and deterioration of the atmosphere inside the furnace.

Therefore, an object of the present invention is to provide a door device for a heating furnace that allows workpieces to be carried into and taken out of a furnace using the smallest possible opening, and that allows the entire opening to be opened during maintenance and inspection inside the furnace. The goal is to provide the following.

[Means to solve the problem]

In this invention, inside the cylindrical furnace chamber whose axial direction is upright,
In a heating furnace, a plurality of turntables are coaxially arranged so as to be rotatable in the horizontal direction, and the furnace wall has an opening through which a workpiece can be inserted and extracted from each of the turntables. A main door means that covers the opening so that it can be opened and closed by moving, a sub-opening provided in the main door means that has an opening area that allows insertion and extraction of a workpiece into one turntable, and a sub-opening that can be opened and closed. The device is characterized by having a sub-door means attached to the main door means so as to cover the main door, and a drive means attached to the main door means for opening and closing the sub-door means.

[For production]

With the above-mentioned configuration, when inserting and extracting a workpiece to the top turntable, the vertical position of the main door means is adjusted so that the opening of the main door means is at the corresponding position, and then the sub-opening is closed. When inserting/extracting a workpiece to/from the lower turntable, the main door means is further lowered to a position corresponding to the lower turntable. Therefore, the only opening that communicates with the outside air is the sub-opening, which has a small opening area, and it is possible to minimize changes in the atmosphere in the furnace due to the insertion and extraction of workpieces.

〔Example〕

Hereinafter, embodiments of the present invention shown in the drawings will be described.

First, the first embodiment shown in FIGS. 1 to 3 will be described. The heating furnace main body 11, only a portion of which is shown, is similar to that described in the above-mentioned patents Nos. 1,339,640 and 1,441.
It has substantially the same configuration as the furnace shown in No. 721,
A detailed explanation thereof will be omitted. In the cylindrical furnace chamber in the heating furnace body 11, there are an upper turntable 13 that rotates around a rotating shaft 12 and a rotating shaft 14 that extends coaxially with the rotating shaft 12.
A lower turntable 15 is provided which rotates separately from the upper turntable 13. A shielding member 16 is interposed between the upper turntable 13 and the lower turntable 15, and the shielding member 16 separates the portion of the upper turntable 13 from the lower turntable 15.
The section allows you to set different furnace temperatures. On the upper turntable 13 is a donut-shaped first
An upper turntable 17 and a second upper turntable 18 having a similar shape to the first upper turntable 17 are attached via a support plate 19. A plurality of workpiece mounting tables 21 are provided on each of the upper surfaces of the upper turntable 13, the lower turntable 15, and the first upper turntable 17 along their outer edges at appropriate intervals. A workpiece 22 is placed on the upper surface of these workpiece mounting tables 21, and a gap is formed in the lower surface to allow the insertion of a fork 51, which will be described later, for inserting and extracting the workpiece 22.

An opening 24 is formed in the furnace wall 23 of the heating furnace main body 11 for inserting and extracting the workpiece 22 . This opening 24 has a height sufficient to allow the hook 51 to insert and extract the workpiece 22 into and out of the workpiece table 21 of the first upper turntable 17 and the workpiece table 21 of the lower turntable 15 in a horizontal state. have. This opening 2
4 is opened and closed by a main door means 25 supported along the outer surface of the furnace wall 23 so as to be movable up and down. Approximately at the center of the main door means 25, a take-out entrance 26 is provided which is large enough to allow the fork 51 carrying the workpiece 22 to enter and exit, and this take-out opening 26 is connected to the first upper turntable 17 and the lower turntable. 15, it is also large enough to cover the opening 24.

The main door means 25 is composed of a plate-shaped core material 27 made of a heat insulating material such as asbestos or ceramic fiber, and an outer panel 28 made of a steel plate that covers the outer peripheral surface of the core material 27. A pair of hollow rectangular supports 31 are attached to the steel wall plate 29 that covers the outer circumferential surface of the furnace wall 23 and are positioned substantially vertically between them so as to sandwich the main door means 25. A substantially U-shaped crosspiece member 32 is disposed such that the open portion is located on the lower surface. Sprockets 33 are rotatably supported at both ends of the crosspiece member 32, and roller chains 34 each having one end fixed to the main door means 25 are meshed with these sprockets 33. The end is fixed to a counterweight 35 that is loosely fitted into the support column 31.

An air, oil, pneumatic, or electric cylinder 36 is installed approximately at the center of the crosspiece member 32. A plunger 37 of this cylinder 36 is installed approximately at the center of the main door means 25, and the amount of movement of the plunger 37 is fixed at approximately the center of the main door means 25. By operating the cylinder 36 to adjust the main door means 25, the main door means 25 is moved up and down.

A sub-door means 38 is provided in front of the take-out opening 26 of the main door means 25.
is installed so that it can move up and down. That is, a pair of guide rails 41 are rotatably attached to both sides of the auxiliary door means 38 and into which the rollers 39 are rotatably fitted, are attached to the front surface of the main door means 25, and approximately at the lower end of the auxiliary door means 38. A plunger 43 of a cylinder 42 similar to the cylinder 36 described above is attached to the center.

Similarly to the main door means 25, the sub-door means 38 also includes a plate-shaped core material 44 and an outer plate 45 that covers the outer peripheral surface of the core material 44. A known frame curtain burner 46 is attached to the upper edge of the take-out opening 26 to cover the take-out opening 26 with a frame curtain when the sub-door means 38 is lowered to expose the take-out entrance 26.

The fork 51 carries the workpiece 22 on its upper surface and is fed into the furnace from the take-out opening 26 through the opening 24, and places the workpiece 22 on the workpiece mounting table 21 and takes the heat-treated workpiece 22 out of the furnace. It is for transportation. A rod-shaped rotating member 52 held substantially horizontally is attached to the rear end of the fork 51. A support shaft 54 supported substantially horizontally by a support plate member 53 is inserted through a substantially central portion of the rotation member 52, and the rotation member 52 is rotatable about this support shaft 54 as a fulcrum. The support plate member 53 is attached to the tip side of one surface of a movable plate member 55 whose surface is supported substantially vertically, and bearing blocks 56 are attached to the four corners of the other surface of this movable plate member 55. . These bearing blocks 56 are fitted into the grooves of the guide rail 57 and move in the longitudinal direction of the guide rail 57, but are of a known type that do not separate from the guide rail 57 unless removed from both ends of the guide rail 57. . The guide rails 57 are provided so as to extend in the longitudinal direction at the upper and lower portions of a rectangular movable support frame 58 which is arranged so that its surface is substantially perpendicular. A support plate 59 is attached to the lower part of the rear end side so that its rear end extends rearward from the rear end of the movable plate member 55, and the upper part of the front side of this support plate 59 has a support plate 59 whose protrusion stroke can be adjusted. An air cylinder 61 that can be adjusted with a screw or the like is attached.

This air cylinder 61 is in contact with the lower surface of the rear end of the rotating member 52, and when operated, pushes up the rear end of the rotating member 52, thereby lowering the fork 51 side. A plunger 63 of a cylinder 62 similar to the cylinder 36 described above is swingably attached to the rear end of the cylinder 52 . This cylinder 62 is connected to the support plate 59
The fork 51 is moved forward into the furnace by the operation of the cylinder 62.

A fixed support frame 68 is located on the back side of the movable support frame 58 and is constituted by three fixed columns 64, 65, 66 and three crosspiece members 67.

Guide rails 69 having the same structure as the guide rail 57 are provided on the surfaces of the fixed columns 64 and 66 on the movable support frame 58 side so as to extend in the vertical direction. A bearing block 71 having a similar structure to the bearing block 56 attached to the back surface of the bearing block 71 is slidably and irremovably fitted. A cylinder 7 similar to the cylinder 36 is attached to the fixed column 65.
2 is attached, and its plunger 73 is attached to the movable support frame 58, and the movable support frame 58 is moved in the vertical direction by the operation of the cylinder 72. A counterweight 74 is inserted into each of the fixed columns 64 and 66 so as to be able to move up and down, and a roller chain 75 with one end attached to the counterweight 74 is attached to the fixed column 64.
and 66 are fixed to the movable support frame 58 via sprockets 77 rotatably attached to sprocket support beam members 76 provided so as to protrude toward the movable support frame 58, respectively. A connecting support member 78 for connecting to the main door means 25 is also attached to the upper part of the movable support frame 58 on the side of the main door means 25.
The main door means 25 is fixed to the connecting column member 78 via an angle member 79 and a fastening bolt 81.

This fixed position is a place where the fork 51 can enter the furnace through the take-out entrance 26 when the fork 51 moves forward substantially horizontally. Therefore, as the movable support frame 58 moves up and down, the main door means 25 also moves up and down. This vertical movement is caused by cylinder 7.
2, and therefore the plunger 73 of the cylinder 72 is mounted so as to be located approximately at the balance point of the total weight of the main door means 25 and the movable support frame 58. By removing the fixing bolt 81, the connection between the main door means 25 and the movable support frame 58 is released.

When inserting the workpiece 22 into the workpiece mounting table 21 of the first upper turntable 17, the cylinder 72 is operated to position the main door means 25 and the movable support frame 58 as shown in FIG. Next, the cylinder 43 is operated to lower the sub door means 38. As a result, the extraction opening 2
6 is opened. Here, the cylinder 62 is operated and the fork 52 with the workpiece 22 placed thereon is taken out from the opening 2.
6 into the furnace of the heating furnace main body 11. When the fork 52 is inserted into the lower part of the workpiece mounting table 21 as shown by the imaginary line in FIG.
Using 4 as a fulcrum, lift it slightly. This allows fork 51
Since the side is lowered, the workpiece 22 is placed on the workpiece mounting table 21.

If the operation of the air cylinder 61 is stopped at this point, the fork 51 is moved backward and ejected from the take-out opening 26.

At this point, the operation of the cylinder 43 is stopped and the auxiliary door means 38 is opened.
is raised to close the take-out opening 26, and the air cylinder 6 is closed.
1 to a non-operating state, and the rotating member 52 is made approximately horizontal.

Workpiece 2 is placed on the workpiece mounting table 21 of the upper turntable 13.
2, the cylinder 72 is operated to position the take-out entrance 26 of the main door means 25 to face the upper turntable 13, and then the fork 51 is advanced by the same operation as described above to load the upper turntable. The workpiece 22 can be placed on the workpiece mounting table 21 of No. 13. The workpiece 22 that has undergone heat treatment can be extracted by locating the takeout opening 26 at a position corresponding to the desired turntable and then operating the air cylinder 61. Insert the fork 51 into the workpiece mounting table 21 with the fork 51 lowered, and then press the air cylinder 6.
If the operation of step 1 is stopped, the fork 51 will rise and the workpiece 22 can be placed on it.
All you have to do is move back 1.

The main door means 25 and the movable support frame 58 having the fork 51 are moved up and down by the cylinder 62, but since the main door means 25 and the movable support frame 58 are each provided with counterweights 35.74,
It can be moved up and down with just one cylinder and with a small amount of force.

When performing maintenance inspection inside the heating furnace main body 11, the movable support frame 58 is removed from the angle member 79 and the connecting column member 78 by removing the fixing bolt 81, and only the movable support frame 58 is raised to the maximum. or lower to open the front side of the main door means 25. Next, by raising only the main door means 25 by operating the cylinder 36, the opening 24 can be exposed, and maintenance and inspection can be performed from this opening 24.

In this way, the fork 51 is attached to the main door means 25 with its vertical position fixed, so there is no need to adjust the height of the fork as in the past, which not only simplifies the operation but also makes the structure simple. can be converted into

The second embodiment shown in FIG. 4 and FIG.
Only the essential parts are shown, and the same or substantially the same components as the first embodiment described above are given the same reference numerals. Detailed explanation will be omitted.

That is, the auxiliary door means 38 that covers the front surface of the exit entrance 26 of the main door means 25 is covered by the bestible 85 attached to the main door means 25. On the front of Bestiple 85,
A bestiple opening 86 for inserting the four-hole 51 is formed, and a bestiple door means 87 that can open and close this bestiple opening 86 is attached to the front surface of the bestiple 85. Like the main and sub-door means 25, 38, the vestible door means 87 is also composed of a plate-shaped core material and an outer plate that covers the outer peripheral surface of this core material. Bestiple door means 87
is slidably held by pressing members 88 on both sides thereof, and has a cylinder 8 similar to the cylinder 36 at its upper end.
9 plungers 91 are attached, and are adapted to move up and down by the operation of the cylinder 89. The cylinder 89 is attached to a support member 92 fixed to the bestible 85.

The bestible door means 87 is formed with an insertion opening 93 through which the rotating member 52 is slidably inserted. When the bestible door means 87 is raised and the bestible opening 86 is opened,
In order to prevent outside air from entering through this opening 86, a frame curtain burner 4 is installed at the lower front of the bestible 85.
A frame curtain burner 94 similar to 6 is attached. Reference numeral 95 represents a regulating valve means for regulating the gas pressure within the bestible 85.

Therefore, in this second embodiment, when inserting and extracting the workpiece 22, the cylinder 89 is first operated to raise the bestible door means 87. Next, move the fork 51 forward so that the tip of the rotating member 52 is aligned with the bestible 85.
When the bestible door means 87 is located inside, the bestible door means 87 is lowered and the bestible door means 87 is closed. bestible door means 8
Since the insertion hole 93 is formed in 7, the rotating member 52
is fitted into this insertion hole 93, and the bestible door means 87 can be lowered to a predetermined position.Next, the sub-door means 38 is opened in the same manner as in the first embodiment described above, and the fork 51 is inserted into the furnace.
By providing the bestiple 85 in this way, the fork 5 can be inserted into the bestiple 85.
1, the inside of the bestible 85 is substantially sealed, and then the sub-door means 38 is opened. Therefore, damage to the atmosphere inside the furnace is greatly improved. Further, since a frame curtain is formed by a frame curtain burner 94 in the insertion opening 93 through which the rotating member 52 passes, it is possible to prevent the flow of gas in the furnace and the intrusion of the atmosphere.

〔Effect of the invention〕

As described above, the heating furnace door device of the present invention is attached to the furnace wall and can be moved vertically to open and close the opening. Since a sub-opening having a large opening area is formed and the sub-door means is attached to the main door means so as to cover the sub-opening in an openable/closable manner, the only opening that communicates with the outside air is the sub-opening having a small opening area. Therefore, changes in the furnace atmosphere due to the insertion and extraction of workpieces can be suppressed as much as possible.

In this invention, the main door means is provided with a bestible in front of the sub-opening, and the opening for inserting and extracting the workpiece into the bestible is also provided with a door means that can be opened and closed, so that the workpiece is once located inside the bestible. After this, the door means of the bestible can be closed and the sub-door means can be opened, thereby further preventing contact between the atmosphere inside the furnace and the outside air.

[Brief explanation of drawings]

FIG. 1 is a side view showing a main part of a first embodiment of the present invention with a part cut away, FIG. 2 is a top view showing a part of FIG. 1 with a cut away, and FIG. FIG. 4 is a front view showing the heating furnace with parts removed, FIG.
It is a front view which shows the heating furnace part removed from the figure. In the drawing, 11 is a heating furnace main body, 13 is an upper turntable, 15 is a lower turntable, 21 is a workpiece mounting table, 22 is a workpiece, 24 is an opening, 25 is a main door means, 2
6 is an extraction opening, 38 is an auxiliary door means, 43 is a plunger,
51 is a fork, 52 is a rotating member, 85 is a bestible,
86 is a bestible opening, and 87 is a bestible door means.

Claims (3)

[Claims] (1) A plurality of turntables are coaxially arranged in a cylindrical furnace chamber whose axial direction is upright so that they can rotate horizontally, and an opening in the furnace wall allows workpieces to be inserted into and extracted from each of the turntables. In the heating furnace, the heating furnace has a main door means attached to the furnace wall and capable of opening and closing the opening by moving in the vertical direction; a sub-opening provided in the main door means, and a sub-door means attached to the main door means so as to cover the sub-opening in an openable and closable manner;
A door device for a heating furnace, comprising: a drive means attached to the main door means for opening and closing the sub door means. (2) The main door means has a bestible in front of the sub-opening, and the bestible door means is also provided in the bestible opening for inserting and extracting the workpiece. The heating furnace door device according to claim 1. (3) further comprising a workpiece conveyance means for inserting and extracting the workpiece into the furnace, the workpiece conveyance means being attached at a position of the main door means capable of being inserted and ejected from the sub-opening; The door device for a heating furnace according to claim 1, wherein the door device moves up and down together with the main door means.