JPH1089851A - Continuous heat treatment furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce vibration during transfer and maintain the degree of freedom of a moving speed in respective zones in a furnace by a method wherein annular rails, guiding a hearth member to freely run, are arranged so as to be passed through respective heat treatment zones while a plurality of driving means, driving the hearth member into one direction, are provided individually in respective heat treatment zones. SOLUTION: A furnace body 1 is provided with a guide means 10, consisting of a pair of annular rails 11, continuously on an internal space 5 and an opening 2 so as to guide a plurality of hearth members 12 runably. A plurality of driving rollers 20, contacted with the inside surface of the base unit of the hearth members 12, are arranged inside of the annular rails 11. The rollers in respective zones are connected to motors, provided in respective zones, through connecting means. Accordingly, the passing speed of hearth members 12, passing through respective zones, can be set by regulating the rotating speed of the motors.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous heat treatment furnace for continuously heat treating an object to be treated.

[0002]

2. Description of the Related Art Conventionally, when firing ceramic parts such as ceramic capacitors, a firing furnace called a roller hearth furnace is used. This roller hearth furnace is a furnace that continuously performs a baking process while transporting an object to be fired in the furnace using a transport roller. The rollers are arranged so as to penetrate the left and right side walls of the furnace body, and are driven by a motor. The ceramic component is housed in a box, and the box (the object to be fired) is placed on a roller, and is continuously conveyed from the inlet to the outlet of the furnace. The furnace body is divided into a plurality of zones in the furnace length direction, and has a structure corresponding to temperature conditions, supply and exhaust gas conditions by changing the roller conveyance speed in each zone.

[0003]

However, since the roller hearth furnace is a linear furnace, when the material to be fired is used repeatedly, an operation for returning the material to be fired from the outlet of the furnace to the inlet is required. However, there is a drawback that work efficiency is reduced and the structure is complicated. Further, in the case of the roller hearth furnace, due to its structure, there is a problem that vibration occurs when the rollers are continuously transferred between the rollers, and the ceramic parts in the object to be fired fall down, and the firing quality is deteriorated.

Therefore, in order to suppress vibration during transport,
A furnace using a continuously rotated turntable has been proposed. However, in this case, since the hearth plate composed of the turntable is constantly moving, the material to be fired is taken in.
Since the removal is difficult and the hearth moving speed is constant, the temperature profile cannot be changed in each zone.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a continuous heat treatment furnace in which vibration during transportation is low and the moving speed in each zone in the furnace has a degree of freedom.

[0006]

To achieve the above object, the present invention provides a heat treatment furnace for continuously heat treating an object to be treated, comprising: a furnace body having a plurality of heat treatment zones;
A plurality of hearth members supporting the object to be processed, and a continuous circling rail for guiding the hearth member so that the hearth member can travel freely, and guide means arranged such that the circulating rail passes through each heat treatment zone of the furnace body. , A plurality of driving means individually provided in each heat treatment zone and driving the hearth member in one direction.

When an object to be processed is placed on a hearth member and the hearth members are individually driven by driving means provided in each heat treatment zone, the hearth member is moved along each of the heat treatment zones of the furnace body along the orbiting rail. Pass through. At this time, since the hearth member is guided by a continuous orbiting rail, the vibration is low, and the workpiece can be continuously fed, so that the shock applied to the workpiece is small, and the hearth is There is no problem such as falling down on the member. Further, since the moving speed in the furnace in each heat treatment zone can be individually set by the driving means, the temperature profile in the furnace can be set variously, and the degree of freedom of the heat treatment is high.

When the orbiting rail of the guide means is formed in a substantially elliptical shape having an arc portion and a linear portion, the heat treatment zone of the furnace corresponding to the linear portion of the orbiting rail is changed to a furnace body corresponding to the arc portion. It is desirable to set the temperature higher than that of the heat treatment zone. In other words, the temperature distribution of the arc is different between the inner and outer diameters, and the influence of radiant heat from other parts is also different. May occur. On the other hand, if the straight portion is in a high temperature range, the temperature unevenness can be reduced, and a uniform heat treatment can be performed.

It is desirable to use a driving roller that comes into contact with the hearth member as the driving means. Since the drive roller only contacts the hearth member, even if the moving speed of the hearth member differs between the zones, it is possible to absorb the difference in speed without shock, and the mechanism is simplified. .

[0010]

1 to 3 show an example of a heat treatment furnace according to the present invention, for example, an example of a heat treatment furnace used for firing a ceramic molded product. The heat treatment furnace of this embodiment includes an annular furnace body 1 made of a refractory such as a brick or a heat insulating material. The furnace body 1 is open only within a certain range (for example, a range of about 90 °). An inlet 3 is formed at one end facing the opening 2 and an outlet 4 is formed at the other end. 4
An arc-shaped internal space 5 is formed therebetween. A heating section 5a is provided above the internal space 5, and a heating heater (not shown) and a gas supply pipe for forming an atmosphere in the furnace are arranged in the heating section 5a. I know. That is, as shown in FIG. 2, the first zone Z ₁ , the second zone Z ₂ , and the third zone Z ₃ from the entrance side.
Has become, for example, the first zone Z ₁ In the degreasing step, the second zone Z ₂ in the firing step, the third zone Z ₃ in the cooling step is performed. The aforementioned opening 2, the inlet zone Z ₅ taken for introducing the extraction zone Z ₄ and the work W for taking out the object to be treated W (hereinafter referred to as work) are provided, these zones Z ₄ and Z ₅ Are provided with a work W take-out device 6 and a work W take-in device 7, respectively. Since the take-out device 6 and the take-in device 7 are conventionally well-known, detailed description will be omitted.

The furnace body 1 is provided with a guide means 10 comprising a pair of circular arc-shaped revolving rails 11.
The circling rail 11 is provided continuously on the internal space 5 and the opening 2. A plurality of hearth members 12 are guided on the rail 11 so that they can run freely. As shown in FIG. 3, a pair of bearings 13 is attached to the lower end base portion 12a of the hearth member 12, and these bearings 13 are engaged with the rails 11 so as to be able to travel. Hearth member 1
A table 12b is provided integrally with the upper part of the table 2, and a work W is placed on the upper surface of the table 12b.

As shown in FIG. 4, a base 12a of a hearth member 12
A plurality of drive rollers 20 are disposed in contact with the inner surface of the drive roller. In this case, it is desirable that the inner surface of the base portion 12a be formed in a concentric arc shape with the rail 11. Each roller 20 is attached to the tip of an arm 21 that can swing in the horizontal direction. Each arm 21 is urged by a spring 22 in a direction in which the roller 20 comes into contact with the inner surface of the hearth member 12. The roller 20 is disposed by plurality in each zone Z ₁ to Z _5, the roller 20 of each zone via a connecting means 24 such as a chain or a belt, connected to the motor 23 provided in each zone Have been. Therefore, by adjusting the rotation speed of the motor 23, each zone Z ₁ to
The rate of passage of the hearth member 12 passing through the Z ₅ can be set individually.

If a plurality of rollers 20 are simultaneously brought into contact with one hearth member 12, the hearth member 1
2 can be driven more stably. Further, in order to eliminate the slip between the roller 20 and the inner surface of the hearth member 12, the roller 20 may be formed of a material having a high coefficient of friction such as rubber.
Knurls or the like may be provided on the hearth member 12 or the hearth member 12.

In this embodiment, the moving speed of the second zone Z ₂ is set lower than the _first and third zones Z ₁ and Z ₃ . Therefore, so that the speed difference at the boundary portion between the boundary portion, and a second zone Z ₂ and the third zone Z ₃ of the first zone Z ₁ and the second zone Z ₂ occurs. Therefore, at the boundary between the first zone Z ₁ and the second zone Z ₂ where the speed changes from high speed to low speed, a friction clutch is provided for the roller 20 on the high speed side (the first zone Z ₁ side), hearth member 12 is brought into contact with the low-speed side (second zone Z ₂ side) roller 20 after down, thereafter, the high-speed side roller 20 that idles by the friction clutch, which absorbs the speed difference and shock. On the other hand, the second zone Z that changes from low speed to high speed
₂ and in the boundary between the third zone Z _3, the low-speed side to the roller 20 (second zone Z ₂ side) may be provided a one-way clutch, the hearth member 12 is high-speed side (Zone 3 Z ₃ side) roller 20 moves at a high speed when it comes into contact with
Zero absorbs the speed difference and shock by idling by the one-way clutch. If a speed difference occurs at another zone boundary, a speed difference absorbing mechanism similar to the above may be provided at that location.

Moreover, the stopper device is installed properly in the opening 2, the hearth member 12 removal zone Z ₄ or intake zone Z
You may make it possible to position with ₅ . As a drive source of the drive roller 20 in the positioning section, it is desirable to use a drive source capable of slow start in order to reduce a shock applied to the work.

In this embodiment, as shown in FIG.
On the left and right side walls of the internal space 5, convex portions 8 are formed so as to enter under the table portion 12 b of the hearth member 12, and these convex portions 8 are brought close to the vertical wall portions 12 c of the hearth member 12. Thereby, the heat loss in the heating unit 5a is suppressed, and the influence of heat on the guide unit 10 and the roller 20 is suppressed to a minimum. As described above, only the table portion 12b of the hearth member 12 is disposed in the heating portion 5a of the internal space 5, and the heat loss is suppressed, so that the heat of the heater can be efficiently transmitted to the work W, and the heater can be used. The minimum capacity is sufficient, and the temperature inside the furnace is small.

Further, since a gap is inevitably formed between the hearth members 12 before and after moving along the rail 11, heat is easily radiated downward from the gap. Therefore, as shown in FIG. 6, the front end and the rear end of the table portion 12b of the hearth member 12 are
It is also possible to suppress the escape of heat from the gap between the front and rear hearth members 12 by projecting the stepped portion 14 or the uneven portion having the meshing shape and engaging these stepped portions 14. Instead of the step portion 14 or the uneven portion as described above, a shielding member such as an elastic bellows may be attached between the front and rear hearth members 12.

Here, the operation of the heat treatment furnace of the above embodiment will be described.
I will tell. First, the intake zone Z_FiveIn the intake device 7
Therefore, while the work W is taken into the hearth member 12, the furnace W
The floor member 12 is held by a stopper device (not shown).
After the work W has been taken in, the hearth member 12 is
It is released from the stopper device. Intake zone Z_FiveDrive b
Roller 20 transports the hearth member 12 to the entrance 3 at a rapid traverse speed.
I do. By adding a slow start mechanism,
Thus, shock due to acceleration and deceleration can be reduced. From entrance 3
The hearth member 12 introduced into the internal space 5 is moved at a degreasing speed.
Turning Zone Z₁Is switched to the drive roller 20. Drive
The switch of the roller 20 is made soft by the speed difference absorption mechanism.
The transfer shock is small. Degreasing zone Z₁
After passing through the furnace, the hearth member 12
Z_TwoIs switched to the drive roller 20 of the speed
Absorb the difference. Main firing zone Z _TwoAfter passing through the hearth
Material 12 is in cooling zone Z_ThreeAnd the work W is gradually cooled
You. Thereafter, the hearth member 12 is removed from the outlet 4 to the removal zone Z._Four
And the hearth member 12 is positioned by the stopper device.
Heat treatment on the hearth member 12 by the removal device 6
The completed work W is taken out. Hearth material after removal
12 is transported at a high speed to an intake position. Then with the above
A similar operation is repeated.

During the heat treatment as described above, the hearth member 12 is stably held by the bearing 13 and the rail 11, so that the vibration caused by running is extremely small. For this reason, problems such as the work W falling down during the heat treatment and the deterioration of the heat treatment quality can be solved. Further, since the work W can be transported at an individual speed by the drive rollers 20 provided in each of the zones Z _{1 to} Z ₃ , the temperature profile can be set freely and various heat treatments can be performed.

FIGS. 7 and 8 show another embodiment of the heat treatment furnace according to the present invention. The furnace body 30 of this embodiment has a circular arc portion 30.
a, 30b and linear portions 30c, 30d are formed in an elliptical shape, and the revolving rail 31 penetrating the inside of the furnace body 30 is also formed in a substantially elliptical shape having arc portions 31a, 31b and linear portions 31c, 31d. ing. One straight portion 30c of the furnace body 30 is open to the outside, and a work take-out device 32 and a work take-in device 33 are arranged corresponding to the opening 30c. The moving speed of the heat treatment zone of the other linear portion 30d of the furnace body 30 is set lower and higher than that of the heat treatment zone of the arc portions 30a and 30b. For example, arc part 3
At 0a, a degreasing process is performed, at the straight portion 30d, a main firing process is performed, and at the circular arc portion 30b, a cooling process is performed.

As shown in FIG. 8, the hearth member 34 has a table portion 34b at an upper end offset outward from a base portion 34a at a lower end, and the base portion 34a and the table portion 34b are connected by a column 34c. . Inside the furnace body 30, a heating space 38 for accommodating the table portion 34b so as to be movable and a passage 39 narrower than the heating space 38 through which the support 34 can be inserted are continuously formed. Base part 34a
A guide roller 35 for holding the both sides of the rail 31 therebetween is attached to the guide roller 35.
5, the hearth member 34 can run smoothly even if the shape of the rail 31 changes.

In the arc portions 30a and 30b of the furnace body 30, a driving roller 36 similar to that of the first embodiment is disposed. These rollers 36 are arranged so as to face the window hole 40 of the furnace body 30, and the rollers 36 are connected to the base portion 34 of the hearth member 34.
The hearth member 34 is conveyed while being inscribed in a. One straight part 3
At 0d, a direct-acting drive device 37 is disposed, and the drive device 37 conveys the hearth member 34 intermittently or continuously. Note that as the driving device 37, any device such as a cylinder system, a ball screw driving system, and a chain driving system may be used. The other straight section 30c is provided with a transfer means such as a free flow conveyor, and is adjusted so that the hearth member 34 can be transferred at an arbitrary interval and speed.

In this embodiment, the linear portion 30d is replaced with the circular arc portion 30.
By setting the temperature higher than a and 30b, temperature unevenness can be reduced and uniform heat treatment can be performed. That is, the arc portions 30a and 30b have different heat radiation areas on the inner diameter side and the outer diameter side, and also have different effects of radiant heat from other portions. While unevenness is likely to occur, the straight section 30
This is because d has a small unbalance between the heat radiation areas of the left and right side walls and the radiant heat, so that uneven temperature distribution hardly occurs.

The above embodiment is only a few examples, and various modifications can be made. The shapes of the furnace body and the rail are not limited to the circular and elliptical shapes as in the embodiment, but may be any shapes having a orbit. The means for driving the hearth member is not limited to a drive roller, and any means such as a cylinder drive or a chain drive may be used. Further, when a substantially elliptical circuit rail is provided, the furnace body may be provided only on the linear portion of the circuit rail. Although three zones are provided inside the furnace body, one, two, or four or more zones may be provided. Further, the moving speeds of the respective zones need not be different from each other, and may be the same. Further, a plurality of independent furnace bodies may be arranged for one orbiting rail.

[0025]

As is clear from the above description, the heat treatment furnace of the present invention has a furnace body having a plurality of heat treatment zones, a plurality of hearth members supporting an object to be processed, and a freely movable hearth member. And a guide means arranged so as to pass through each heat treatment zone of the furnace body, and provided separately in each heat treatment zone, and drives the hearth member in one direction. Since a plurality of driving means are provided, the hearth member is guided by a continuous orbiting rail, so that the vibration is low, the shock applied to the object is small, and the object falls down on the hearth member. There are few defects. Further, since the moving speed in the furnace in each heat treatment zone can be individually set by the driving means, the temperature profile in the furnace can be variously set, and the degree of freedom of heat treatment is high.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of a heat treatment furnace according to the present invention.

FIG. 2 is a plan view of the heat treatment furnace of FIG.

FIG. 3 is an enlarged view of a main part of the heat treatment furnace of FIG.

FIG. 4 is a plan view of driving means for driving a hearth member.

FIG. 5 is a sectional view taken along line AA of FIG. 2;

FIG. 6 is a perspective view of a modified example of a hearth member.

FIG. 7 is a plan view of a heat treatment furnace according to a second embodiment of the present invention.

FIG. 8 is a sectional view taken along line BB of the heat treatment furnace of FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace body 2 Opening 5 Internal space 10 Guide means 11 Circulating rail 12 Hearth member 20 Drive roller W Work (workpiece)

Claims (3)

[Claims] 1. A heat treatment furnace for continuously heat-treating an object to be processed, a furnace body having a plurality of heat treatment zones, a plurality of hearth members supporting the object to be processed, and a hearth member capable of running freely. A guide means having a continuous orbiting rail for guiding, the orbiting rail being arranged to pass through each heat treatment zone of the furnace body; and a plurality of individually provided in each heat treatment zone for driving the hearth member in one direction. A continuous heat treatment furnace, comprising: 2. The continuous heat treatment furnace according to claim 1, wherein the orbiting rail of the guide means is formed in a substantially elliptical shape having an arc portion and a linear portion, and the furnace corresponds to the linear portion of the orbiting rail. The heat treatment zone of the body is set at a higher temperature than the heat treatment zone of the furnace body corresponding to the arc portion. 3. The continuous type heat treatment furnace according to claim 1, wherein said driving means has a driving roller which comes into contact with a hearth member.