JPS61272586A - Roller hearth type vacuum furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention aims to solve the following problems.

(Industrial Application Field) The present invention relates to a roller hearth type vacuum furnace in which a workpiece is heated in a vacuumed furnace.

(Prior art) In this type of roller hearth type vacuum furnace, there is no gas in the furnace, and the radiant heat from the heat source is transferred to the workpiece only by radiation, so the workpiece is moved between the rollers. When heating is performed while the object is placed on top of the roller, radiant heat is applied to the part of the object that is in the shadow of the roller.
There was a problem that the temperature rise in that part was delayed.

(Problems to be Solved by the Invention) This invention eliminates the above-mentioned conventional problems and prevents a part of the workpiece from being in the shadow of the transfer roller, thereby achieving uniform heating of the entire workpiece. The purpose of this project is to provide a roller hearth type vacuum furnace that enables the following.

The configuration of the present invention is as follows.

(Means for Solving the Problems) The present invention takes the measures as described in the claims above, and its effects are as follows.

(Operation) The object to be processed is sent into the furnace body from the inlet and is guided to the holding space by the transfer roller.

At that location, the object to be processed is lifted from the transfer roller by the lifting means, and heated in that state. Next, when the predetermined heating is completed, the object to be processed is placed on the transfer roller again by lowering of the lifting means, carried by the transfer roller from the storage space to the exit, and sent out from there.

(Example) Below, drawings showing examples of the present application will be described. Sintering furnace l shown as an example of a roller hearth vacuum furnace
2, a furnace body has a waiting chamber 3, a dewaxing chamber 4, a sintering chamber 5, a cooling chamber 6, etc. inside the furnace body. Furthermore, code 4
a, 5a, and 6a indicate spaces for storing objects to be processed in each chamber. The furnace body 2 is made of a metal material, and has a water-cooled structure as required. The sintering chamber 5 is separated from other chambers by a metal partition wall 7.8. 9 is the charging port;
Reference numerals 10 and 10 indicate the loading and unloading exits, respectively, and doors 11 and 12 that can be raised and lowered.
It can be opened and closed freely. Reference numerals 13 and 14 indicate lifting devices for the doors 11 and 12, respectively. Next, reference numerals 15 and 16 indicate transfer rollers, which are rotatably attached to the furnace body 2.The structure of the sintering chamber 5 will be described in more detail. Reference numeral 17 denotes a heat insulating wall disposed to surround the space for storing the object to be processed, and is made of a material such as graphite, and its inner surface is mirror-finished so that radiant heat is well reflected. Reference numeral 18 indicates a number of heat sources arranged along the inner surface of the heat insulating wall 17, for example, electric heaters are used. Reference numerals 19 and 20 indicate an entrance door and an exit door that close the entrances 19a and 20a of the sintering chamber 5, respectively. These doors consist of an outer frame 21 made of a metal material and a heat insulating plate 22 provided inside the outer frame 21. It is possible to make contact, and in that contact state,
The insulating board 22 connects the inlet 19a and the outlet 2 in the insulating wall 17.
It is designed so that it can come into contact with the peripheral portion of 0a. As a result, the inside of the sintering chamber 5 is hermetically sealed, and the object to be processed 50
The storage space is surrounded by a heat insulating wall 17 and a heat insulating plate 22. Reference numeral 23 indicates the opening/closing device of the above field. In this structure, reference numeral 24 denotes an elevating frame, which can be moved up and down to a certain position by a guide (not shown) attached to the furnace body 2. Reference numeral 25 indicates a lifting device for the lifting frame 24. Reference numeral 26 indicates a parallel link connecting the door and the lifting frame 24. According to the opening/closing device 23 having such a configuration, when the elevator frame 24 is lowered and the door 19 (or 20) faces the entrance 19a (or the exit 20a), the lower part of the door is received by a receiving member not shown. When stopped, further lowering of the door is prevented. In this state, when the elevating frame 24 is further lowered, a force is applied to the door to press it against the partition wall. As a result, the sealed state described above is achieved. On the other hand, when the lifting frame 24 rises, the pressing force disappears, and the door opens onto the lifting frame 2.
4 and move upwards.

Next, the structure related to the transfer roller 16 will be explained based on FIG. 2. The transfer roller 16 has bearings 27, 2
A metal shaft 28 rotatably supported by 7
and an annular receiving member (
(For example, made of graphite) 29 is attached, and the shaft 28
The part facing the internal space of the heat insulating wall 17 is covered with the heat insulating material 3.
covered by 0. A sprocket 31 is attached to one end of the shaft 28, and the sprocket is connected to a known rotation means 32. As a result, the transfer roller 16 is rotated by the operation of the rotation means 32. The above-mentioned shaft 28 may have a water-cooled structure. or,
In some cases, the transfer roller 16 may be entirely or partially made of ceramic.

Next, the lifting means 34 provided in the sintering chamber 5 will be explained. 35 is a rotating shaft, which is rotatably supported by a bearing 36. 37 is an eccentric cam attached to the rotating shaft 35;
Reference numeral 8 denotes an elevating plate placed on the cam, and a plurality of lifting rods 39 are installed on the upper surface of the elevating plate in an upright state. (made of thermal material) 40 is the installation. As shown in FIG. 4, the lifting piece 40 has a projected area on the lower surface of the workpiece 50 that is significantly smaller than the projected area of the transfer roller 16 on the workpiece 50. Reference numeral 41 denotes a retaining member that connects the partition wall 7 and the lifting plate 38, and is provided to prevent the lifting plate 38 from moving in the left-right direction in FIG. 1 when the eccentric cam 37 rotates. .

Next, since the dewaxing chamber 4 has substantially the same configuration as the sintering chamber 5, members that are considered to have the same or equivalent configuration as each member in the sintering chamber 5 are given the same reference numerals as in the case of the sintering chamber 5. will be added to omit duplicate explanations.

Next, in the cooling chamber 6, 42 is a fan, 43 is a motor,
44 is a cooler, 45 is a guide plate, and when the fan 42 is rotated by the operation of the motor 43, the gas inside flows as shown by the arrow in FIG. It is designed to come into contact with the object 50 and cool it.

In FIG. 1, reference numerals 51 and 52 indicate transport carts, each of which is equipped with a roller 53 on its upper surface for placing the object 50 thereon. It is now possible to transport processed materials.

In the normal operation method of the above configuration, the waiting room 3
The dewaxing chamber 4 is brought to atmospheric pressure, while the sintering chamber 5 is
Then, the cooling chamber 6 is brought into a vacuum state and the operation is started. First, the workpiece 50 that has been sent on the transport vehicle 51 is
When the door 11 is opened, it is introduced into the waiting room 3 through the loading port 9,
The door 11 is closed again, and the waiting room 3 and the dewaxing room 4 are closed.
is evacuated to a vacuum state. Next, the entrance door 19 of the wax removal chamber 4 is opened, the object to be processed 50 is guided onto the transfer roller 16 in the wax removal chamber 4, and the entrance door 19 is closed. . In this state, the workpiece 50 is lifted by the lifting device 34 as will be described later, and then heated by radiant heat emitted from the heat source 18. This heating is performed, for example, to about 650°C. After heating as described above for a predetermined period of time, the object to be processed 50 is placed on the transfer roller 16 again. Next, the exit m20 of the dewaxing chamber 4 and the entrance door 19 of the sintering chamber 5 are opened, and the object to be processed is transferred onto the transfer roller 16 toward the storage space in the sintering chamber 5. The door 20.19 is then closed again, the workpiece 50 is lifted off the transfer roller 16 by the lifting device 35, and the heat source 18 is activated and the workpiece 50 is lifted up by the radiant heat emitted from it.
is heated.

The heating is performed at, for example, about 1200°C. After the heating as described above continues for a predetermined period of time, the object to be processed 50 is placed on the transfer roller 16 again, the exit door 20 is opened, and the object to be processed 50 is cooled from above the transfer roller 16. It is sent out onto the transfer rollers 15 in the chamber 6.

After the exit door 20 is closed, cooling gas is introduced, the fan 42 and the cooler 44 are operated, and the object to be processed 50 is cooled. This is how you get treated! Once the Ik 50 has cooled to a predetermined temperature, a valve communicating with the atmosphere (not shown) is opened, the door 12 is opened, and the material to be processed is sent out from the outlet 10 onto the carrier 52. 50 is carried to the next process.

When heating the workpiece 50 in the dewaxing chamber 4 or sintering chamber 5 as described above, the rotating shaft 3 in the lifting device 34
5 is rotated by the rotating means 35a.

As a result, the elevator plate 38 is raised by the eccentric cam 37, and the lifting means 40 provided at the upper end of the lifting rod 39 lifts the workpiece 50 and moves it away from the roller 16.

In this state, the object to be processed 50 is irradiated with radiant heat that is directly irradiated from a large number of heat sources 18, and after being radiated from those heat sources 18, it is reflected by the inner surface of the heat insulating wall 17, and then the object to be processed 50 is irradiated. It is heated by radiant heat and becomes high temperature. In this case, as described above, the object to be processed 50 is heated not only by the direct radiant heat from the heat source 18 but also by the radiant heat reflected by the inner surface of the heat insulating wall 17, so that some parts around the object to be processed 50 are heated. heat source 18
Even if there is no heat source 18, the portion of the object 50 facing that side is heated by the radiant heat reflected by the heat insulating wall 17 on that side in the same way as when the heat source 18 is present. Therefore, in this specification, the heat source 18 that directly irradiates radiant heat to the object to be processed 50 and the wall surface of the heat insulating wall 17 that reflects the radiant heat and irradiates the object to be processed 50 with the reflected radiant heat are generally referred to as Also called heat radiation surface. Therefore, in the furnace configured as described above, heat radiating surfaces are present at both the top, bottom, right and left of the space 5a for storing the workpiece 50.

When heating the object 50 as described above, the fifth
The workpiece 50 is moved to the roller 1 as shown by the two-dot chain line in the figure.
6, the part 50a of the workpiece 50 located directly above the roller 16 would be exposed to only radiant heat from a very small range as shown by the angle α.In contrast, in this example, the above-mentioned Since the object to be processed 50 is lifted by the lifting member, the above-mentioned portion 50a located directly above the roller 16 is also irradiated with radiant heat from a wide range as shown by the angle β. Therefore, part 5 above
The radiant heat given to 0a does not decrease much compared to other parts, and as a result, it is heated similarly to other parts.

During heating as described above, the rotating means 32 may be operated to rotate the roller 16. In this case, since the roller 16 is in an idling state, it is sufficient to keep it rotating in one direction. When the roller 16 is rotated in this manner, the portion 16a facing downward in FIG. 5, for example, receives radiant heat from below and becomes high in temperature. Eventually, as the roller 16 rotates, the portion 16a turns upward and faces the lower surface of the workpiece 50. In this state, the above-mentioned portion 16a can apply radiant heat toward the lower surface of the object to be processed 50,
The lower surface of the object to be processed 50 is heated by the radiant heat.

Such action continues as the roller 16 rotates. As a result, uniform heating of the lower surface of the object to be processed 50 can be achieved.

Furthermore, in the heating state, the lower surface of the workpiece 50 is not in contact with the roller 16, so the heat of the workpiece 50 is prevented from escaping out of the furnace through the roller 16, and the local temperature of the workpiece 50 is reduced. Deterioration is prevented.

Furthermore, according to the method of heating the workpiece 50 while being lifted by a lifting member as described above, the heat treatment can be performed while the workpiece 50 is kept in a fixed position in the furnace. The internal dimensions of the furnace can be made small enough to accommodate the workpiece 50, and the unit consumption, heat capacity, and evacuation volume can be reduced, and the evacuation pump can be made smaller. Furthermore, damage caused by the object to be processed 50 colliding with components in the furnace can also be prevented.

In the above-mentioned apparatus, the workpiece 50 is placed in the furnace body 2.
Each time a new workpiece 5 is transferred to the next chamber, a new workpiece 5 is introduced from the charging port 9.
0 may be charged, and each treatment may be performed simultaneously in each chamber in the furnace body 2.

Next, FIG. 6 shows a different embodiment, in which a heat insulating wall 17e
This shows an example in which heat a 188 is provided only on the side of the space 5ae for holding the object to be processed 50e.

Even in such a configuration, as described above, the inner surfaces of the heat insulating walls above and below the storage space 5ae for the workpiece 50e reflect radiant heat and irradiate the workpiece 50e with it.
The inner surfaces of these insulating walls act as heat radiating surfaces.

It should be noted that parts that are functionally the same or equivalent to those in the previous figure are given the same reference numerals and the letter e, and redundant explanations are omitted.

(Also, in the next version, the same idea will be added with the alphabet f and redundant explanation will be omitted.

Next, Figure 7 shows a different example of the configuration of the lifting device.
This shows an example in which the lifting means 40f is moved up and down by a fluid cylinder 55. In both figures, a piston rod 56 is inserted into the furnace body 2f through a sealing device 57 attached to the furnace body 2r, and the elevating plate 38f is attached to the upper end of the piston rod.

(Effects of the Invention) As described above, in the present invention, when the workpiece 50 is heat-treated, the workpiece 50 is placed at the inlet 19a.
It is then slid onto the transfer roller 16 and placed in the holding space 5a, where it is heated by radiant heat from the upper and lower heat radiation surfaces, and after being subjected to a certain heat treatment, it is placed again. Exit 2 by sliding on transfer roller 16
It has the advantage of being able to send out from 0a.

Moreover, when heating the workpiece 50 in the storage space 5a, if the transport roller 16 is located below the workpiece 50, the heat will be applied downward to the part of the underside of the workpiece that is in the shadow of the transport roller. Even if radiant heat is not applied from the radiation surface and the temperature rise there is insufficient and the overall temperature uniformity may be impaired, the object to be processed 50 can be lifted by the lifting means 40 and its lower surface transferred. By moving the workpiece away from the transfer roller 16, the radiant heat from below can easily hit the part of the workpiece's lower surface located directly above the transport roller, and the temperature rise on the workpiece's underside can be approximately evened out in each part. - It has the effect of making people feel negative.

Furthermore, during the above-mentioned heating, the workpiece 50 is lifted and separated from the transfer roller 16, so that the transfer roller 1
It has the advantage of being able to turn 6 arbitrarily.

This not only has the effect of preventing the transfer roller from bending due to local heating from the heat radiation surface below, but also has the effect of preventing the transfer roller from bending when it is facing downward. It receives thermal energy from the heat radiation surface and becomes high in temperature, and then when the heated part faces upward, radiant heat can be applied to the lower surface of the object to be processed, and the object to be processed 50 can be uniformly heated. It has the usefulness of further promoting the heating effect.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and FIG. 1 is a longitudinal cross-sectional view of a sintering furnace, FIG. 2 is a cross-sectional view taken along the nm line, FIG. 3 is a cross-sectional view taken along the mm line, and FIG. FIG. 5 is a plan view showing the relationship between the lifting roller, the lifting means, and the workpiece; FIG. 5 is a diagram for explaining the state of radiant heat irradiation on the lower surface of the workpiece; FIG. 6 is an example of a different arrangement of the heat source. FIG. 7 is a partial view showing a different embodiment of the lifting device. 2... Furnace body, 5a... Storage space, 19a... Inlet, 20a... Outlet, 16... Transfer roller, 50
...Processed object, 40... Lifting means. Figure 2 j5 Figure 3 Figure 4 I/I Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] A part of the hollow furnace body, which has a space for storing the object to be treated inside, is provided with an inlet for introducing the object to be treated from the outside into the furnace body, and an outlet for taking the object to be taken out from the inside to the outside. A plurality of transfer rollers are arranged in a lower position inside the furnace body to transfer the workpiece from the inlet to the holding space and from the holding space to the exit. Further, within the furnace body, heat radiating surfaces are disposed above the storage space and below the storage space, respectively, to radiate radiant heat toward the storage space, and further, A lifting means that can be raised and lowered to lift the workpiece from the transfer roller is disposed below the holding space, and the projected area of the lifting means with respect to the lower surface of the workpiece is A roller hearth type vacuum furnace characterized in that the projected area of the transfer roller on the lower surface of the furnace is significantly smaller than that of the transfer roller.