JP6707364B2 - Heat treatment equipment - Google Patents

Description

The present invention relates to a heat treatment apparatus having an oil bath used for quenching a work.

In a heat treatment apparatus, an oil tank used for quenching is usually provided in a heat treatment furnace (for example, refer to Patent Document 1). In the heat treatment furnace, the work heated to a high temperature is immersed in the oil tank to quench the work. After that, the work is lifted from the oil tank, deoiled, and then carried out from the carry-out port of the heat treatment furnace.

In such a heat treatment apparatus, a frame curtain for closing the carry-out port with a flame is usually formed in order to prevent air from entering through the carry-out port. By preventing the air from entering the heat treatment furnace, the atmosphere is prevented from being disturbed or exploded in the heat treatment furnace.

JP, 11-124621, A

However, in the above-mentioned heat treatment apparatus, when the work passes through the frame curtain while being carried out of the heat treatment furnace, the quenching oil adhering to the work surface may catch fire. When the quenching oil burns due to such ignition, the state of the work (for example, the hardness of the work) changes, and there is a possibility that problems such as variations in characteristics may occur in the work after the heat treatment.

Therefore, an object of the present invention is to provide a heat treatment apparatus in which problems such as characteristic variations are unlikely to occur in a work after quenching using an oil tank.

A heat treatment apparatus according to the present invention includes a heat treatment furnace, a frame curtain forming mechanism, and a gas injection mechanism. The heat treatment furnace has an oil tank used for quenching the work and an outlet for carrying out the work after quenching. The frame curtain forming mechanism forms a frame curtain that closes the carry-out port of the heat treatment furnace with a flame. The gas injection mechanism blows an inert gas onto the work immediately after passing through the frame curtain when it is carried out from the carry-out port of the heat treatment furnace.

According to the heat treatment apparatus described above, even if the flame of the quenching oil adhering to the surface of the work ignites when the work passes through the frame curtain, the flame is immediately extinguished by the inert gas. Therefore, the work is not easily affected by the flame of the frame curtain. That is, when the work is carried out, the state of the work (for example, the hardness of the work) hardly changes.

In the specific configuration of the heat treatment apparatus, the heat treatment apparatus further includes a transfer mechanism that transfers the work along a transfer path that passes through the carry-out port. The gas injection mechanism injects the inert gas from above the transfer passage into the transfer passage, and injects the inert gas from the side position of the transfer passage into the transfer passage. It has a 2nd injection part. According to this configuration, it is possible to efficiently blow the inert gas onto the work.

In a more specific configuration, the first injection unit is provided with a shield plate that blocks the flow of the inert gas toward the formation position of the frame curtain. With this configuration, the flame curtain is less likely to be affected by the inert gas pushing down the reaching point of the flame that blows upward.

In another more specific configuration, the work is stored in the work storage tool, and the work storage tool is transported along the transport path. Then, when the work storage device passes through the position where the inert gas is sprayed by the gas injection mechanism, the distance from the upper end of the work storage device to the first injection part is from the side end of the work storage device to the second injection part. The first injection unit and the second injection unit are arranged so as to be smaller than the distance. With this configuration, the inert gas can be efficiently blown to the entire work stored in the work storage tool. As an example, the work storage device is a stack of a plurality of storage baskets for storing the work.

In another specific configuration of the heat treatment apparatus, the distance X from the position where the frame curtain is formed to the position where the inert gas is sprayed in the workpiece transport direction is set within the range of t1·Cs≦X≦t2·Cs. Has been done. Here, Cs is the transport speed (m/sec) of the work, and t1=1 sec and t2=1.5 sec.

According to the heat treatment apparatus of the present invention, problems such as characteristic variations are unlikely to occur in a work after quenching using an oil tank.

It is a fracture|rupture side view which showed notionally the principal part of the heat processing apparatus. It is a perspective view which each showed (a) tray and (b) storage basket. It is the front view which showed the structure of the gas injection mechanism with which a heat processing apparatus is equipped. It is a fracture side view showing composition of a gas injection mechanism in the 1st modification. It is a front view showing the composition of the gas injection mechanism in the 2nd modification.

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

[1] Configuration of Heat Treatment Apparatus As shown in FIG. 1, the heat treatment apparatus includes a heat treatment furnace 1, a transfer mechanism 2, a frame curtain forming mechanism 3, and a gas injection mechanism 4. As an example, the heat treatment apparatus is an apparatus that performs a carburizing process on a work such as a gear. The components of the heat treatment apparatus described in detail below are not limited to those for carburizing, but can be applied to various heat treatment apparatuses that perform quenching using an oil tank in the heat treatment process.

[1-1] Heat Treatment Furnace The heat treatment furnace 1 heats a work conveyed by the conveyance mechanism 2 with quenching. Specifically, the heat treatment furnace 1 has an oil tank 11 used for quenching a work, a carry-out port 12 through which the work after quenching is carried out, and a door 13 capable of opening and closing the carry-out port 12.

In the heat treatment furnace 1, first, the work is heated to a high temperature. In the present embodiment, at this time, the work is heated in the gas atmosphere for carburization, so that carbon permeates the work surface. Next, the work is rapidly cooled by being immersed in the quenching oil 11a stored in the oil tank 11. Such rapid cooling of the work improves the hardness of the work. After that, the work is lifted up from the oil tank 11 and drained. Then, the work is carried out from the carry-out port 12 after the door 13 is opened.

[1-2] Transport Mechanism The transport mechanism 2 is a mechanism for transporting the work along the transport path 20 passing through the carry-out port 12. In the present embodiment, the transport mechanism 2 is a tray pusher, and transports the work along the transport passage 20 by pushing the tray 21 on which the work is placed. As an example, as shown in FIG. 2A, the tray 21 is formed of a frame plate 211 that constitutes a rectangular frame and a partition plate 212 that partitions the inside of the frame into a grid pattern. With such a tray 21, oil can pass vertically inside the oil tank 11 surrounded by the frame plate 211. The structure of the tray 21 is not limited to the structure shown in FIG. 2A, and various modifications are possible.

The work is stored in the storage basket 22, and the storage basket 22 is placed on the tray 21. As an example, as shown in FIG. 2B, the storage basket 22 has a rectangular inlet opening upward and side walls and a bottom wall made of a mesh metal material. According to such a storage basket 22, since oil can pass through the side wall and the bottom wall of the storage basket 22 in the oil tank 11, the oil flows into the storage basket 22 and the oil is removed from the storage basket 22. It is possible to let it out. Further, when the work is lifted up from the oil tank 11, the oil dripping from the work can be guided downward through the storage basket 22.

Further, according to the storage basket 22, when the inert gas is blown as will be described later, the inert gas is made to flow into the storage basket 22 in the vertical direction and the horizontal direction, and the inert gas is discharged from the storage basket 22. Can be drained. The configuration of the storage basket 22 is not limited to the configuration shown in FIG. 2B, and various modifications are possible. Further, for storing the work, various work storage tools not limited to the storage basket 22 can be used.

In the present embodiment, a plurality of storage baskets 22 are stacked on the tray 21, and these storage baskets 22 are transported along the transport passage 20 as a work storage tool. The transfer passage 20 is a passage that enables the transfer of such a work storage tool (a plurality of storage baskets 22 stacked on the tray 21).

As shown in FIG. 1, the transfer passage 20 includes a first passage 20 a used to convey a work in the heat treatment furnace 1 and a second passage 20 b used to convey a work carried out from the carry-out port 12. Including and In the present embodiment, the second passage 20b is defined by the skid rail 23. A predetermined distance is provided between the carry-out port 12 and the end 23a of the skid rail 23 located in the vicinity of the carry-out port 12, and in this space, the frame curtain forming mechanism 3 and the gas injection mechanism described below. A part of the mechanism 4 (third injection unit 43) is arranged.

[1-3] Frame Curtain Forming Mechanism The frame curtain forming mechanism 3 forms the frame curtain 31 that closes the carry-out port 12 of the heat treatment furnace 1 with a flame. In the present embodiment, the frame curtain forming mechanism 3 blows the flame upward from the lower position of the transport passage 20. Further, the frame curtain forming mechanism 3 starts forming the frame curtain 31 when the work is carried out from the carry-out port 12 and immediately before the door 13 is opened. After that, the frame curtain forming mechanism 3 continues to form the frame curtain 31 until the work is carried out and the door 13 is closed. The timing of forming the frame curtain 31 is not limited to this.

[1-4] Gas Injecting Mechanism The gas injecting mechanism 4 blows an inert gas onto the work immediately after passing through the frame curtain 31 at the time of carrying out from the carry-out port 12. Specifically, the gas injection mechanism 4 blows an inert gas onto the work at a position opposite to the carry-out port 12 with respect to the formation position Pf of the frame curtain 31. For example, nitrogen gas is used as the inert gas. The inert gas is preferable because it does not disturb the atmosphere or explode in the heat treatment furnace 1 even if the inert gas flows into the heat treatment furnace 1.

A more specific structure of the gas injection mechanism 4 is shown in FIG. The skid rail 23 is not shown in FIG. 3 (the same applies in FIG. 5). Further, the injection direction of the inert gas is indicated by the arrow. As shown in FIG. 3, the gas injection mechanism 4 includes a first injection unit 41, second injection units 42A and 42B, and a third injection unit 43. Here, the first injection unit 41 injects the inert gas downward from the position above the transfer passage 20 toward the inside of the transfer passage 20. Each of the second injection units 42</b>A and 42</b>B injects the inert gas from the lateral position of the transport passage 20 into the transport passage 20. Specifically, the second injection unit 42A injects the inert gas rightward from the left position of the transfer passage 20 toward the inside of the transfer passage 20. The second injection unit 42B injects the inert gas leftward from the right side position of the transfer passage 20 toward the inside of the transfer passage 20. The third injection unit 43 injects the inert gas upward from the position below the transfer passage 20 toward the inside of the transfer passage 20.

In the present embodiment, the first injection unit 41, the second injection units 42A and 42B, and the third injection unit 43 each include four pipes 44a, 44b and 44c, and 44d that surround the transport passage 20. Has been done. Specifically, these pipes 44a to 44d are connected to each other in an annular shape and are also connected to an inert gas supply pipe 45. In addition, a plurality of through holes (injection ports of inert gas) that are opened toward the transport passage 20 are provided on the side walls of each of the pipes 44a to 44d. Then, by supplying the inert gas to the pipes 44a to 44d through the supply pipe 45, the inert gas is injected from the through hole. The pipes 44a to 44d and the supply pipe 45 may be provided with a solenoid valve or the like that enables control of the flow of the inert gas. Further, the configuration of the gas injection mechanism 4 is not limited to the above-described configuration, and various modifications are possible.

In the present embodiment, the gas injection mechanism 4 starts the injection of the inert gas when the work is carried out from the carry-out port 12 and immediately after the door 13 is opened. After that, the gas injection mechanism 4 continues to inject the inert gas until the work finishes passing through the frame curtain 31. The timing of injecting the inert gas is not limited to this.

According to the gas injection mechanism 4, even if the flame ignites the quenching oil 11a adhering to the surface of the work when the work passes through the frame curtain 31, the flame is immediately extinguished by the inert gas. It Therefore, the work is unlikely to be affected by the flame of the frame curtain 31. That is, when the work is carried out, the state of the work (for example, the hardness of the work) hardly changes. Therefore, problems such as characteristic variations are unlikely to occur in the work after quenching using the oil tank 11.

After passing through the frame curtain 31, t1≦t≦t2 (here, t1=1 second, t2=1) is set at the position Pg (see FIG. 1) at which the inert gas is sprayed from above and from the side by the gas injection mechanism 4. It is preferable to set the position where the work reaches after a time t defined by 0.5 seconds). This position is appropriately set according to the transport speed Cs (m/sec) of the work. That is, the distance X from the formation position Pf of the frame curtain 31 to the spraying position Pg in the direction along the transport path 20 (transport direction) is preferably set within the range of t1·Cs≦X≦t2·Cs. . From the viewpoint of preventing the influence of the inert gas on the frame curtain 31, the distance X preferably satisfies X≧t1·Cs (t1=1 second). Further, from the viewpoint of efficiently extinguishing the fire by the gas injection mechanism 4, the distance X preferably satisfies X≦t2·Cs (t2=1.5 seconds).

In the present embodiment, the pipes 44b and 44c arranged on the left and right of the transfer passage 20 are connected to the pipe 44d arranged below the transfer passage 20 with their lower ends bent in a crank shape. .. As a result, while the third injection unit 43 is adjacent to the frame curtain formation mechanism 3, the first injection unit 41 and the second injection units 42A and 42B are different from the frame curtain formation mechanism 3 with respect to the third injection unit 43. It is arranged on the other side.

[2] Modified Example A modified example of the heat treatment apparatus described above will be described.

[2-1] First Modification As shown in FIG. 4, the first injection unit 41 is provided with a shielding plate 46 that blocks the flow of the inert gas toward the formation position Pf of the frame curtain 31. Is preferred. Specifically, the shielding plate 46 is provided in the pipe 44a so as to be interposed between the through hole (injection port of the inert gas) provided in the pipe 44a and the frame curtain 31. As a result, the frame curtain 31 is less susceptible to the influence that the reaching point of the flame that blows upward is pushed down by the inert gas.

[2-2] Second Modification It is preferable that the first injection unit 41 and the second injection units 42A and 42B are arranged as follows (see FIG. 5). That is, the positions Pg (see FIG. 1) at which the inert gas is blown from above and from the side by the gas injection mechanism 4 are stacked on the tray 21 into a plurality of storage baskets 22 (hereinafter, referred to as “workpieces” in this modification). (Hereinafter referred to as "storage device"), the distance L1 from the upper end of the work storage device to the first injection part 41 is the distance L2 from the left end of the work storage device to the second injection part 42A or the right side of the work storage device. It is preferable that the first injection unit 41 and the second injection units 42A and 42B are arranged so as to be smaller than at least one of the distances L3 from the end to the second injection unit 42B. As an example, the distance L1 is set to 90 mm, and each of the distances L2 and L3 is set to 165 mm. The distances L1 to L3 are not limited to this, and can be appropriately changed according to the size of the work storage device or the like.

When a plurality of storage baskets 22 are stacked on the tray 21, the inert gas blown from the side easily flows laterally between the storage baskets 22 and thus easily reaches the center of the work storage device. On the other hand, the inert gas blown from above is blocked by the work or the like in the storage basket 22 and is unlikely to reach the central portion of the work storage device. Therefore, in order that the inert gas blown from above reaches the central portion of the work storage tool, the first injection part 41 may be brought close to the upper end position of the work storage tool when passing the spray position Pg. preferable. Further, according to such a configuration, it becomes possible to efficiently blow the inert gas to the entire work stored in the plurality of storage baskets 22.

The description of the above embodiments is to be considered as illustrative in all points and not restrictive. The scope of the invention is indicated by the claims rather than the embodiments described above. Further, the scope of the present invention is intended to include meanings equivalent to the claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Heat treatment furnace 2 Transport mechanism 3 Frame curtain formation mechanism 4 Gas injection mechanism 11 Oil tank 11a Quenching oil 12 Carrying outlet 13 Door 20 Transport passage 20a 1st passage 20b 2nd passage 21 Tray 22 Storage basket 23 Skid rail 23a End 31 Frame curtain 41 1st injection part 42A, 42B 2nd injection part 43 3rd injection part 44a, 44b, 44c, 44d Pipe 45 Supply pipe 46 Shield plate 211 Frame plate 212 Partition plate L1, L2, L3 Distance Pf Formation position Pg Spray position Cs Transport speed X Distance t time

Claims (5)

A heat treatment furnace having an oil tank used for quenching the work and an outlet for carrying out the work after quenching,
A frame curtain forming mechanism that forms a frame curtain that closes the carry-out port with a flame,
When carried out from the carry-out port, a gas injection mechanism for blowing an inert gas onto the work immediately after passing through the frame curtain,
A transport mechanism for transporting the work along a transport path passing through the carry-out port,
The gas injection mechanism,
A heat treatment apparatus having a first injection part for injecting an inert gas from a position above the transfer passage toward the inside of the transfer passage . The gas injection mechanism,
A second injection unit for injecting inert gas toward the conveying passage from the lateral position of the transport passage, a heat treatment apparatus according to claim 1. The heat treatment apparatus according to claim 2, wherein the first injection unit is provided with a shielding plate that blocks the flow of the inert gas toward the formation position of the frame curtain. The work is stored in a work storage tool, the work storage tool is transported along the transport path,
When the work storage device passes the position where the inert gas is sprayed by the gas injection mechanism, the distance from the upper end of the work storage device to the first injection unit is the second end from the side end of the work storage device. The heat treatment apparatus according to claim 2 or 3, wherein the first injection unit and the second injection unit are arranged so as to be smaller than a distance to the injection unit. The heat treatment apparatus according to claim 4, wherein the work storage device includes a plurality of storage baskets in which the works are stored and stacked.

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