JPH0468292A - Roller hearth type vacuum furnace - Google Patents

Abstract

PURPOSE:To reduce the penetrating places of rollers through a furnace shell, simplify the structure of a furnace and facilitate the assemblage as well as the maintenance of the same by a method wherein some rollers among all rollers are constituted of driving rollers and the other rollers are constituted of free rollers while the driving rollers are arranged below moving trays and the downwardly movable free rollers are arranged between neighboring treating chambers. CONSTITUTION:One or two pieces of driving rollers 10a, 10b exist below a tray 24 whereby the tray 24 is transferred to a transfer direction X by these driving rollers. In this case, free rollers 10c, 10d are rotated freely. When the shifting of a work W to be treated between heating chambers is finished, the free roller 10d is moved downwardly whereby the possibility of interferrence between a door 4 as well as the opening and closing mechanism therefor and the free roller 10d is eliminated and the door 4 or another door 7 can be closed without any trouble. The free rollers 10c, 10d are not projected to the outside of a furnace shell 3 and, therefore, the number of airtight sealing places can be reduced while the free rollers do not necessitate a coupling chain or the like and, therefore, the structure of the furnace can be simplified and the trouble of the same can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a roller hearth type vacuum furnace for heating a workpiece in a vacuum state.

[Conventional technology]

Generally, in a roller hearth vacuum furnace, all the rollers for conveying the workpiece are driven by a chain driven by an electric motor. In this case, there are many problems such as the need for vacuum sealing devices at multiple locations in the furnace shell penetration area, which increases manufacturing costs and is cumbersome to assemble, as well as being prone to leakage (intrusion of outside air) and requiring maintenance. .

Therefore, attempts have been made to prevent the shaft ends of the rollers other than those that are directly chain-driven by the motor from protruding outside the furnace shell, and to drive these rollers with interlocking chains inside the shell, but this approach has caused problems due to the furnace temperature. Since high-temperature treatments often exceed 1200°C, the heat resistance of the interlocking chain and lubrication methods are major issues, and the slackness of the interlocking chain cannot be adjusted outside the furnace, making it extremely difficult to put it into practical use.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, and is a roller hearth type vacuum furnace that requires fewer roller passage points and sealing points, and is easy to assemble and maintain. This is what we are trying to provide.

[Means to solve the problem]

However, in the roller hearth type vacuum furnace of the first invention of this application, in a roller hearth type vacuum furnace equipped with rollers for conveying the workpiece, some rollers out of all the rollers are configured with drive rollers, and other rollers are configured with drive rollers. The present invention is characterized in that the rollers are free rollers, and the drive rollers are arranged so that at least one drive roller exists below the tray on which the workpiece is placed and moves.

Moreover, the roller hearth type vacuum furnace of the second invention of this application is
In a roller hearth type vacuum furnace that is equipped with rollers for conveying the workpiece and has multiple processing chambers connected, some of the rollers are driven rollers, and the other rollers are free rollers. At the same time, the drive rollers are arranged so that at least one drive roller exists under the tray on which the objects to be processed are moved, and the rollers between adjacent processing chambers are moved from the transport position to the side (including the bottom). ) is characterized by a free roller that can be moved to.

In this invention, the drive roller refers to a roller that is directly driven by a motor via a chain, gear, or coupling, and a roller that is driven by an interlocking means such as an interlocking chain or a gear mechanism. shall be called.

[Effect]

In the roller hearth type vacuum furnace of the present invention, the tray carrying the workpiece is transported into the furnace by one or more drive rollers located below the tray. During this conveyance, the free roller rotates freely and supports the tray and the heavy molten metal of the workpiece on it. Since the free roller can be provided within the furnace shell, the number of penetration points through the furnace shell is reduced, the number of sealing points is reduced, the furnace structure is simplified, and the roller assembly is facilitated.

Furthermore, since the free roller is not connected to a drive mechanism or interlocking mechanism, it is easy to move. For this reason, especially in a multi-chamber type furnace where multiple processing chambers are connected, if the rollers between adjacent processing chambers are free rollers that can be moved laterally from the conveyance position, the free rollers can move when the processing chamber door is closed. can be retracted to avoid interference between the part or its opening/closing device and the free roller.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

In the figure, reference numeral 1 denotes a roller hearth type vacuum furnace, which has a plurality of processing chambers 2a, 2b, and 2G arranged in series from the inlet side.

Reference numeral 3 designates a furnace shell of each processing chamber 2 (general term for processing chambers 2a to 2C; hereinafter, other parts are also collectively referred to in the same manner), and 4 is an airtight door. Inside each processing chamber 2, there is a heating chamber 6 surrounded on all four sides by a heat insulating wall 5 made of graphite and equipped with an electric heater (not shown).
8 to 6C are provided. 7 is a door for heat insulation of each heating chamber 6. Reference numeral 8 denotes a door opening/closing device mainly composed of an air cylinder 9, which is a known mechanism for opening/closing the doors 4 and 7 and driving them down. 10 is a roller for transporting the workpiece W into the furnace, 10a and 10b are drive rollers, and 10c and 10d are free rollers. As shown in the second figure, the drive roller 10a is rotatably supported by a bearing 11 and a bearing 12 that also serves as a sealing device, and a drive sprocket 14 and an interlocking subrocket 1- are attached to one shaft end 13 that protrudes outside the furnace FI 93. 15 is fixed to the drive sprocket 14 and is directly rotationally driven by a motor 17 via a chain 16 wrapped around a drive sprocket 14. Also, the drive O-ra 10b
has the same structure as the drive roller 10a, except that it does not have the drive sprocket 14, and the drive roller 10 is
It is interlocked and driven by a. On the other hand, the free roller 10C is rotatably supported at both shaft ends by bearings 18 provided in the furnace shell 3, as shown in the third figure. Also adjacent processing room 2
The free roller 10d disposed between a and 2b and between 2b and 2c is connected to an air cylinder 19 as shown in the fourth figure.
It is rotatably supported by a bearing 21 on a lifting table 20 which is driven when raised by a bearing 21. Reference numeral 22 designates a storage chamber that accommodates the free roller 10d that has been retracted downward from the processing object transport position shown in FIG. 5, and 23 designates a guide rail that guides the lifting table 20. The drive rollers 10a, 10b and the free rollers 10c, 10d are connected to the tray 2 for conveying the workpiece.
Regardless of the moving position of the tray 24, at least one drive roller 10a or 10b is arranged under the tray 24 (in this embodiment, there is a minimum of one drive roller and a maximum of two drive rollers).

In the roller hearth type vacuum furnace 1 having the above configuration, the workpiece W placed on the tray 24 is loaded into the furnace by opening the furnace inlet doors 4 and 7 at the left end in FIG. It is transported through a furnace and heat-treated in a predetermined vacuum in each processing chamber 2. From inside the heating chamber 6a to inside 6b,
Furthermore, when transporting the object to be processed from inside the heating chamber 6b to inside 6C, after raising the doors 4 and 7 as shown in FIG. 5, the air cylinder 19 is used to raise the free roller 10d. It is stopped at the transport position and supports 24 of the trays to be transported. Since there are one or two drive rollers 10a or 10b under the tray 24,
The tray 24 is conveyed in the conveyance direction indicated by arrow X by these drive rollers.

At this time, free rollers 10c and 10d rotate freely. When the transfer of the workpiece W between the heating chambers is completed, the free roller 10d is lowered to the state shown in the first figure, and there is no possibility of interference between the door 4 and its opening/closing mechanism and the free roller 10d, and the door can be opened without any problem. 4 and 7 can be closed.

Since the free rollers 10c and 10d do not protrude outside the furnace shell 3, there are fewer airtight sealing locations, and the free rollers do not require an interlocking chino or the like, so the SI is simple and there are fewer failures.

The present invention is not limited to the above-mentioned embodiment. For example, the free rollers 10d between adjacent processing chambers may be moved horizontally in the direction of the furnace and retracted from the conveyance position, or 4 or its opening/closing device,
It may be fixedly arranged at the conveyance position similarly to the tree roller 10C. Further, the first invention can also be applied to a single-chamber roller hearth type vacuum furnace having one processing chamber.

〔Effect of the invention〕

As explained above, according to the present invention, the free rollers among the rollers for conveying the processed material can be provided inside the furnace shell, so the number of penetration points of the furnace shell by the rollers is reduced, the furnace structure is simplified, and assembly is possible. In addition to being easy to maintain, the reduction in sealing points reduces the intrusion of outside air into the furnace, and the space for the vacuum pump can also be made smaller. Furthermore, if the roller between the processing chambers is a free roller that can be moved laterally from the conveyance position, interference between the free roller and the processing chamber door or opening/closing device can be avoided, and the distance between the processing chambers and the overall length of the furnace can be reduced. It is possible to shorten the time.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a vertical cross-sectional view of essential parts of a roller hearth vacuum furnace, Fig. 2 is a cross-sectional view taken along the line A-A in Fig. 1, and Fig. 3 is a cross-sectional view taken along the line A-A in Fig. 1. 4 is a sectional view taken along the same <C-CFII line, and FIG. 5 is a partial longitudinal sectional view of the furnace of FIG. 1 showing the processing chamber door in an open state. 1...Roller hearth type vacuum furnace, 2a, 2b, 2c...
- Processing chamber, 10... Rollers, 10a, 10b... Drive rollers, 10c, 10d... Free rollers, 19.
...Air cylinder, 20...Elevating platform, 22...Accommodation chamber, 24...Tray

Claims (1)

[Claims] 1. In a roller hearth type vacuum furnace equipped with rollers for conveying the workpiece, some of the rollers are configured as drive rollers, and other rollers are configured as free rollers. A roller hearth type vacuum furnace, characterized in that a drive roller is arranged so that at least one drive roller exists below a tray on which a workpiece is placed and moves. 2. In a roller hearth type vacuum furnace that is equipped with rollers for conveying the workpiece and has multiple processing chambers, some of the rollers are driven rollers, and the other rollers are free rollers. At the same time, the drive rollers are arranged so that at least one drive roller exists under the tray on which the objects to be processed are placed and moved, and the rollers between adjacent processing chambers can be moved laterally from the conveyance position. A roller hearth type vacuum furnace characterized by a free roller.