Continuous heating furnace

Abstract

To increase the versatility of continuous heating furnaces. [Solution] In the constant speed zone Z1, multiple conveyor rollers 22 rotate at a predetermined rotational speed. Multiple drive division zones SZ1 and SZ2 are provided continuously with respect to the constant speed zone Z1. The rapid traverse zone Z2 is provided continuously with respect to the multiple drive division zones SZ1 and SZ2. In the rapid traverse zone Z2, the rotational speed of the multiple conveyor rollers 22 is configured to be faster than in the constant speed zone Z1. In the constant speed zone Z1, the workpiece 5 is conveyed at a predetermined first conveying speed. In the rapid traverse zone Z2, the workpiece 5 is conveyed at a second conveying speed. The control device is configured to determine the conveying speeds of the multiple drive division zones SZ1 and SZ2 based on the size of the workpiece 5 along the conveying direction.

Description

Technical Field

[0001] The present invention relates to a continuous heating furnace. Background Art

[0002] Japanese Unexamined Patent Publication No. 2023-147792 discloses a continuous firing furnace comprising a tunnel-shaped furnace body surrounding a conveyance space, a plurality of conveyance rollers arranged along a conveyance direction set in the conveyance space, a drive device that rotationally drives the plurality of conveyance rollers, and a control device. A first constant speed zone and a fast-forward zone are set in the conveyance space. In the first constant speed zone, the plurality of conveyance rollers rotate at a predetermined first speed, and a plurality of conveyed articles are conveyed at predetermined intervals. The fast-forward zone is provided rearward continuously from the first constant speed zone. The conveyance space includes a first sensor configured to detect a conveyed article at a predetermined position from the boundary between the first constant speed zone and the fast-forward zone. The fast-forward zone is configured to allow changing the rotation speed of the plurality of conveyance rollers, and is configured to convey conveyed articles at a faster speed than the first constant speed zone. The control device acquires the size of the conveyed article to be conveyed along the conveyance direction and the conveyance speed of the first constant speed zone. The control device is configured such that, based on the timing at which a conveyed article is detected by the first sensor, the timing for increasing the conveyance speed of the fast-forward zone is determined so that the conveyance speed of the fast-forward zone is increased after the conveyed article has moved from the first constant speed zone into the fast-forward zone. Prior Art Literature Patent Literature

[0003] Patent Literature 1 Japanese Unexamined Patent Publication No. 2023-147792 Summary of the Invention Problem to be Solved by the Invention

[0004] Incidentally, the inventors of this invention want to increase the versatility of the continuous heating furnace so that when processing multiple types of workpieces with different dimensions, each workpiece can be heat-treated more appropriately. [Means for solving the problem]

[0005] The continuous heating furnace disclosed herein comprises a tunnel-shaped furnace body enclosing a transport space for transporting a workpiece along a predetermined transport path, a plurality of transport rollers arranged along the transport path of the workpiece, a plurality of drive devices for rotating the plurality of transport rollers, and a control device. The transport path is divided into a constant-speed zone where the plurality of transport rollers rotate at a predetermined rotational speed, a plurality of drive division zones provided continuously with the constant-speed zone, and a rapid-feed zone provided continuously with the plurality of drive division zones, where the rotational speed of the plurality of transport rollers is faster than that of the constant-speed zone. Drive devices are provided in the constant-speed zone, the plurality of drive division zones, and the rapid-feed zone, respectively. In the constant-speed zone, the workpiece is transported at a predetermined first transport speed. In the rapid-feed zone, the workpiece is transported at a second transport speed faster than the first transport speed. The control device is configured to determine the transport speed of each of the plurality of drive division zones based on the size of the workpiece along the transport direction. This continuous heating furnace is highly versatile. [Brief explanation of the drawing]

[0006] [Figure 1] Figure 1 is a schematic side cross-sectional view showing a continuous heating furnace according to a reference example. [Figure 2] Figure 2 is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] Figure 3 schematically shows the area near the outlet of the continuous heating furnace proposed here. [Figure 4] Figure 4 is a schematic diagram showing the arrangement of the drive mechanism. [Figure 5] Figure 5 is a block diagram of a continuous heating furnace. [Figure 6] Figure 6 is a schematic diagram illustrating an example of control by a control device. [Figure 7] Figure 7 schematically illustrates another example of control by a control device. [Figure 8] Figure 8 schematically illustrates another example of control by a control device. [Modes for carrying out the invention]

[0007] Hereinafter, an embodiment of the technology disclosed herein will be described with reference to the drawings. Naturally, the embodiment described herein is not intended to particularly limit the present invention. Furthermore, components and parts that perform the same function will be appropriately denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate. In the drawings, the reference numerals F, Rr, L, R, U, and D represent front, back, left, right, up, and down, respectively. The front-back direction is perpendicular to the left-right direction. The up-down direction is perpendicular to both the front-back and left-right directions. However, the directions defined herein are merely for the convenience of explanation and do not limit the present invention unless otherwise specified.

[0008] Figure 1 is a schematic side cross-sectional view showing a continuous heating furnace 1 according to a reference example. Figure 2 is a cross-sectional view taken along line II-II of Figure 1. In the continuous heating furnace 1, the workpiece 5 is heated while being transported on rollers. The continuous heating furnace 1 may be used to heat the workpiece 5 when hot pressing the workpiece 5. The continuous heating furnace 1 may be used, for example, to manufacture structural parts for automobiles. The workpiece 5 may be, for example, a steel plate. The continuous heating furnace 1 comprises a furnace body 10, a plurality of heaters 20, a plurality of transport rollers 22, and a drive mechanism 30. The basic structure of such a continuous heating furnace is known technology. Therefore, any parts that are not mentioned in this specification and are not adequately explained can be understood to the extent that they can be implemented by a person skilled in the art based on various known technologies.

[0009] The furnace body 10 is formed in a tunnel shape. The furnace body 10 encloses a transport space 10a through which the workpiece 5 is transported along a predetermined transport path. In the configuration shown in Figure 1, the transport path is set along the front-to-back direction, and the workpiece 5 is transported from rear to front. In Figure 1, the transport direction in which the workpiece 5 is transported is indicated by a white arrow. Here, the transport direction is the front-to-back direction. Therefore, the upstream side of the transport direction means the rear side, and the downstream side of the transport direction means the front side. Figure 1 illustrates the transport of a workpiece 5 of size L1. In this specification, the size L1 of the workpiece 5 refers to its size along the transport direction.

[0010] The furnace body 10 may be constructed by stacking ceramic fiber boards that have been molded into a predetermined shape. The ceramic fiber board is, for example, a plate material formed into a plate shape by adding inorganic fillers and inorganic-organic binders to so-called bulk fiber. For example, the ceramic fiber boards may be stacked in the vertical direction. As shown in Figure 2, the furnace body 10 may be provided on, for example, a base 18. Note that the base 18 is not shown in Figure 1.

[0011] As shown in Figures 1 and 2, the furnace body 10 has a bottom wall 11, a pair of side walls 12 and 13, a top wall 14, a rear wall 15, and a front wall 16. The thickness of each wall of the furnace body 10 is set to a thickness sufficient to adequately insulate the heat of the transport space 10a. Although not shown in the figures, the furnace body 10 may be covered with a metal (e.g., stainless steel) outer wall.

[0012] As shown in Figure 2, the bottom wall 11, the pair of side walls 12 and 13, and the top wall 14 are formed in a substantially rectangular parallelepiped shape. The bottom wall 11 extends in the front-to-back and left-to-right directions. The side wall 12 extends upward from the left end of the bottom wall 11. The side wall 13 extends upward from the right end of the bottom wall 11. Although not shown in the figure, the pair of side walls 12 and 13 have multiple through holes through which the conveyor rollers 22 are inserted. The top wall 14 rests on the upper ends of the pair of side walls 12 and 13. The left-to-right ends of the top wall 14 are supported by the pair of side walls 12 and 13.

[0013] As shown in Figure 1, the rear wall 15 extends upward from the rear end of the bottom wall 11. The rear wall 15 supports the rear end of the ceiling wall 14. The front wall 16 extends upward from the front end of the bottom wall 11. The front wall 16 supports the front end of the ceiling wall 14.

[0014] The furnace body 10 has an inlet 11a and an outlet 11b. The inlet 11a is an opening for loading the workpiece 5 into the transport space 10a. The inlet 11a is formed in the rear wall 15. The outlet 11b is an opening for unloading the workpiece 5 from the transport space 10a. The outlet 11b is formed in the front wall 16. Here, the inlet 11a and the outlet 11b are formed in a rectangular shape.

[0015] The heater 20 is arranged inside the furnace body 10. The heater 20 heats the workpiece 5 in the transfer space 10a. A plurality of the heaters 20 are arranged along the transfer direction. In the embodiment shown in FIG. 1, the plurality of heaters 20 are arranged at predetermined intervals along the front-rear direction. In the embodiment shown in FIG. 1, thirteen heaters 20 are arranged in a single row along the front-rear direction. In the embodiment shown in FIG. 1, the heaters 20 arranged in a single row are respectively provided at the upper part and the lower part of the transfer space 10a, and sandwich the transfer rollers 22 in the vertical direction. Here, the heater 20 is formed in a cylindrical shaft shape and penetrates the pair of side walls 12 and 13. Various types of heaters 20 can be used according to the heating conditions of the workpiece 5, for example, a ceramic heater can be used. The number and arrangement of the heaters 20 are not limited to the embodiment shown in FIG. 1, and can be appropriately changed according to the dimensions of the furnace body 10 and the like. Although not shown in the figure, a temperature sensor for measuring the temperature of the transfer space 10a may be attached to the furnace body 10. The output of the heater 20 may be controlled based on the measurement result of the temperature sensor.

[0016] The plurality of transfer rollers 22 are arranged along the transfer direction. In the embodiment shown in FIG. 1, the plurality of transfer rollers 22 are arranged at predetermined intervals along the front-rear direction. The rearmost transfer roller 22 among the plurality of transfer rollers 22 is arranged rearward of the carry-in port 11a and outside the furnace body 10. The frontmost transfer roller 22 among the plurality of transfer rollers 22 is arranged forward of the carry-out port 11b and outside the furnace body 10.

[0017] The transfer roller 22 is formed in a hollow cylindrical shaft shape. For the transfer roller 22, for example, a ceramic material with high heat resistance such as alumina may be used. However, a metal material such as heat-resistant cast steel and stainless steel may also be used for the transfer roller 22. The inner diameter, outer diameter and length of each transfer roller 22 are substantially the same except for allowable manufacturing errors. In the embodiment shown in FIG. 2, both end portions in the left-right direction of the transfer roller 22 are supported by support columns 24 arranged outside the furnace body 10.

[0018] The drive mechanism 30 is attached to the conveying rollers 22. In the embodiment shown in Fig. 2, the drive mechanism 30 is provided on the left side of the furnace body 10. In the embodiment shown in Fig. 2, the drive mechanism 30 includes a plurality of driven sprockets 31, a chain 32, a drive sprocket 33, and a drive device 25. The plurality of driven sprockets 31 are respectively attached to the plurality of conveying rollers 22. The chain 32 is wound around the plurality of driven sprockets 31 and the drive sprocket 33. The drive device 25 is attached to the drive sprocket 33. The drive device 25 is a drive source that rotates the plurality of conveying rollers 22. The type of the drive device 25 is not particularly limited. Here, the drive device 25 is an electric motor. It should be noted that the drive mechanism 30 may optionally include a tension roller (not shown) for adjusting the slack of the chain 32, a guide roller 34 (see Fig. 4) around which the chain 32 is wound, and the like.

[0019] As described above, the continuous heating furnace 1 can be used for hot pressing of the workpiece 5. Hot pressing is a processing method in which the workpiece 5 is pressed at a high temperature to deform the workpiece 5 into a desired shape. In order to appropriately perform hot pressing, it is necessary to convey the workpiece 5 heated by the continuous heating furnace 1 to a press machine without cooling it as much as possible. Here, according to the findings of the present inventor, since the workpiece 5 unloaded from the discharge port 11b is located outside the furnace body 10, it is easily cooled by the outside air. Accordingly, the present inventor intends to suppress the temperature drop of the workpiece 5 by unloading the heated workpiece 5 from the inside of the furnace body 10 at a high speed and shortening the time that the workpiece 5 is exposed to the outside air. In addition, for example, even in quenching treatment of steel materials, it is necessary to rapidly cool the steel material after holding it at a predetermined temperature. Even in such applications, there are cases where it is desired to unload the heated workpiece 5 from the inside of the furnace body 10 at a high speed.

[0020] In the configuration shown in Figure 1, the transport path is divided into a constant-speed zone Z1 and a rapid-forward zone Z2. The constant-speed zone Z1 extends from the outside to the inside of the furnace body 10. In the configuration shown in Figure 1, the loading port 11a is located within the constant-speed zone Z1. In the constant-speed zone Z1, multiple transport rollers 22 rotate at predetermined rotational speeds, and the workpiece 5 is transported at a predetermined first transport speed V1. Here, the first transport speed V1 can be appropriately set according to the dimensions of the furnace body 10 and the heating conditions of the workpiece 5. For example, the first transport speed V1 may be set within the range of 4 m / min to 16 m / min. However, the first transport speed V1 is not limited to the above range and can be appropriately set according to the dimensions of the continuous heating furnace 1 and the heating conditions of the workpiece 5.

[0021] The rapid traverse zone Z2 is provided in conjunction with the constant speed zone Z1. In the configuration shown in Figure 1, the rapid traverse zone Z2 is located in front of the constant speed zone Z1. Therefore, the workpiece 5 is transported from the constant speed zone Z1 to the rapid traverse zone Z2. The rapid traverse zone Z2 extends from inside the furnace body 10 to the outside of the furnace body 10. In the configuration shown in Figure 1, the discharge port 11b is located within the rapid traverse zone Z2. In the configuration shown in Figure 1, the boundary B between the constant speed zone Z1 and the rapid traverse zone Z2 is located inside the furnace body 10 and is positioned upstream of the discharge port 11b in the transport direction.

[0022] In the rapid traverse zone Z2, the rotational speed of multiple conveyor rollers 22 can be changed, and the rotational speed of the multiple conveyor rollers 22 can be made faster than in the constant speed zone Z1. This allows the conveying speed of the workpiece 5 to be changed in the rapid traverse zone Z2. In the rapid traverse zone Z2, the workpiece 5 is conveyed at a second conveying speed V2. Here, the second conveying speed V2 is faster than the first conveying speed V1. The second conveying speed V2 may be set, for example, within the range of 90 m / min to 120 m / min. However, the second conveying speed V2 is not limited to the value within the above range and can be set appropriately according to the dimensions of the continuous heating furnace 1 and the heating conditions of the workpiece 5.

[0023] The conveyor rollers 22 in the constant-speed zone Z1 and the conveyor rollers 22 in the rapid-forward zone Z2 are configured to rotate independently of each other. Here, the conveyor rollers 22 in the constant-speed zone Z1 and the conveyor rollers 22 in the rapid-forward zone Z2 are fitted with independent drive mechanisms 30. In the rapid-forward zone Z2, the conveyor rollers 22 are driven intermittently. After the entire workpiece 5 has moved from the constant-speed zone Z1 to the rapid-forward zone Z2, the workpiece 5 is conveyed at a second conveyor speed V2. That is, after the entire workpiece 5 has moved to the rapid-forward zone Z2, the workpiece 5 is discharged at high speed. By configuring the continuous heating furnace 1 in this way, the workpiece 5 heated by the heater 20 can be discharged at high speed, and the temperature drop of the workpiece 5 can be suppressed.

[0024] Incidentally, for a workpiece 5 with a long size L1 along the conveying direction, it takes longer for the entire workpiece 5 to move from the constant speed zone Z1 to the rapid traverse zone Z2 compared to a workpiece 5 with a short size L1 along the conveying direction. If the boundary B between the constant speed zone Z1 and the rapid traverse zone Z2 is set to match the workpiece 5 with a short size L1 along the conveying direction, then when processing a workpiece 5 with a long size L1 along the conveying direction, it takes longer for the entire workpiece 5 to move from the constant speed zone Z1 to the rapid traverse zone Z2. Also, the front end of the workpiece 5 may protrude outside the furnace body 10, potentially causing a partial temperature drop. On the other hand, if the boundary B between the constant speed zone Z1 and the rapid traverse zone Z2 is set to match the workpiece 5 with a long size L1 along the conveying direction, then when processing a workpiece 5 with a short size L1 along the conveying direction, the rapid traverse zone Z2 is set to be long, causing the workpiece 5 to be removed from the furnace body 10 prematurely, preventing effective use of the space within the furnace body 10. Based on the above considerations, the inventors of the present invention aimed to improve the versatility of the continuous heating furnace 1 by enabling appropriate heat treatment of multiple types of workpieces 5 with different dimensions.

[0025] Figure 3 is a schematic diagram showing the area near the outlet 11b of the continuous heating furnace 1 proposed herein. In the continuous heating furnace 1 proposed herein, the transport path is divided into a constant speed zone Z1, multiple drive division zones, and a rapid traverse zone Z2. In the configuration shown in Figure 3, the transport path is divided into a constant speed zone Z1, two drive division zones SZ1 and SZ2, and a rapid traverse zone Z2. In Figure 3, the drive division zone located upstream (rear) in the transport direction is denoted as SZ1, and the drive division zone located downstream (front) in the transport direction is denoted as SZ2. In the following description, drive division zone SZ1 will be referred to as the first drive division zone, and drive division zone SZ2 will be referred to as the second drive division zone as appropriate.

[0026] The first drive division zone SZ1 is provided continuously with the constant speed zone Z1. The second drive division zone SZ2 is provided continuously with the first drive division zone SZ1. The rapid traverse zone Z2 is provided continuously with the second drive division zone SZ2. In this embodiment, the boundary B2 between the second drive division zone SZ2 and the rapid traverse zone Z2 is provided on the outlet 11b side of the furnace body 10. The distance between boundary B2 and the inlet 11a is greater than the distance between boundary B2 and the outlet 11b. In this embodiment, the outlet 11b is located within the rapid traverse zone Z2. In Figure 3, the boundary between the first drive division zone SZ1 and the constant speed zone Z1 is denoted by the symbol B0. Similarly, in Figure 3, the boundary between the second drive division zone SZ2 and the first drive division zone SZ1 is denoted by the symbol B1, and the boundary between the second drive division zone SZ2 and the rapid traverse zone Z2 is denoted by the symbol B2.

[0027] Boundary B0 is the upstream end in the transport direction of the first drive division zone SZ1 and the downstream end in the transport direction of the constant speed zone Z1. Boundary B1 is the upstream end in the transport direction of the second drive division zone SZ2 and the downstream end in the transport direction of the first drive division zone SZ1. Boundary B2 is the downstream end in the transport direction of the second drive division zone SZ2 and the upstream end in the transport direction of the rapid traverse zone Z2.

[0028] The lengths of the drive division zones SZ1 and SZ2 increase in order from the downstream drive division zone in the conveying direction. That is, if the length of the second drive division zone SZ2 is X2 and the length of the first drive division zone SZ1 is X1, then X2 > X1. Here, the lengths of the drive division zones SZ1 and SZ2 are the lengths along the conveying direction. For example, if the size L1 of the workpiece 5 to be heated in the continuous heating furnace 1 is 500 mm to 2000 mm, then X2 = 500 mm and X1 = 300 mm. The lengths of the drive division zones SZ1 and SZ2 can be appropriately changed according to the value of the size L1 of the workpiece 5 to be heated in the continuous heating furnace 1. Also, the length of the rapid traverse zone Z2 is longer than the lengths of the drive division zones SZ1 and SZ2. For example, if the size L1 of the workpiece 5 to be heated in the continuous heating furnace 1 is 500mm to 2000mm, the length of the rapid traverse zone Z2 may be approximately 1700mm to 1800mm.

[0029] As shown in Figure 3, if D1 is the distance between the outlet 11b and boundary B1, and D2 is the distance between the outlet 11b and boundary B2, then D1 = D2 + X2. Therefore, D1 > D2. The value of D2 can be appropriately set according to the dimensions of the workpiece 5 processed in the continuous heating furnace 1. For example, if the size L1 of the workpiece 5 to be heated in the continuous heating furnace 1 is 500 mm to 2000 mm, then D2 may be approximately 1200 mm. Here, the distance between the outlet 11b and boundary B1 refers to the distance between the outermost part of the furnace body 10 within the outlet 11b and boundary B1, as shown in Figure 3. Similarly, the distance between the outlet 11b and boundary B2 refers to the distance between the outermost part of the furnace body 10 within the outlet 11b and boundary B2.

[0030] Figure 4 is a schematic diagram showing the arrangement of the drive mechanism 30. In this embodiment, the conveyor rollers 22 in the constant speed zone Z1, the drive division zones SZ1 and SZ2, and the rapid traverse zone Z2 are each fitted with a drive mechanism 30 that is independent of each other. The drive devices 25 are provided in the constant speed zone Z1, the drive division zones SZ1 and SZ2, and the rapid traverse zone Z2, respectively. As a result, the first drive division zone SZ1, the second drive division zone SZ2, and the rapid traverse zone Z2 are configured to allow the rotational speeds of the multiple transport rollers 22 to be changed independently of each other. The drive division zones SZ1 and SZ2 are configured to transport the workpiece 5 at a first transport speed V1 and to transport the workpiece 5 at a second transport speed V2.

[0031] In the following description, the drive mechanism 30 in the constant speed zone Z1 is denoted by reference numeral 30R, the drive mechanism 30 in the first drive division zone SZ1 is denoted by reference numeral 30a, the drive mechanism 30 in the second drive division zone SZ2 is denoted by reference numeral 30b, and the drive mechanism 30 in the rapid traverse zone Z2 is denoted by reference numeral 30c, for appropriate distinction. Furthermore, the drive device 25 provided in the drive mechanism 30R is denoted by reference numeral 25R, the drive device 25 provided in the drive mechanism 30a is denoted by reference numeral 25a, the drive device 25 provided in the drive mechanism 30b is denoted by reference numeral 25b, and the drive device 25 provided in the drive mechanism 30c is denoted by reference numeral 25c, for appropriate distinction.

[0032] Figure 5 is a block diagram of the continuous heating furnace 1. The continuous heating furnace 1 includes a first sensor 35, a second sensor 40, a third sensor 42, and a control device 60.

[0033] The first sensor 35 detects whether the workpiece 5 is located at the boundary B0 between the constant speed zone Z1 and the first drive division zone SZ1. In this embodiment, as shown in Figure 2, the first sensor 35 is a photoelectric sensor having a light-emitting unit 36 ​​and a light-receiving unit 37. The light-emitting unit 36 ​​is attached to the side wall 12. The light-emitting unit 36 ​​is configured to emit light. The light-emitting unit 36 ​​may be, for example, an LED or a laser diode. The light-receiving unit 37 is attached to the side wall 13. The light-receiving unit 37 receives light emitted from the light-emitting unit 36. The light-receiving unit 37 may be, for example, a light-receiving element such as a photodiode.

[0034] In this embodiment, when the object to be processed 5 is located at boundary B0, the light emitted from the light-emitting unit 36 ​​is blocked by the object to be processed 5. Therefore, when the object to be processed 5 is located at boundary B0, the light-receiving unit 37 cannot receive the light emitted from the light-emitting unit 36. In this specification, the state in which the light-receiving unit 37 is not receiving light emitted from the light-emitting unit 36 ​​is defined as the "OFF state". On the other hand, in this embodiment, when the object to be processed 5 is not located at boundary B0, the light emitted from the light-emitting unit 36 ​​is not blocked by the object to be processed 5. Therefore, when the object to be processed 5 is not located at boundary B0, the light-receiving unit 37 can receive the light emitted from the light-emitting unit 36. In this specification, the state in which the light-receiving unit 37 is receiving light emitted from the light-emitting unit 36 ​​is defined as the "ON state".

[0035] The second sensor 40 detects whether the workpiece 5 is located at the boundary between adjacent drive division zones among a plurality of drive division zones. In this embodiment, the second sensor 40 detects whether the workpiece 5 is located at the boundary B1 between the first drive division zone SZ1 and the second drive division zone SZ2. The third sensor 42 detects whether the workpiece 5 is located at the boundary B2 between the second drive division zone SZ2 and the fast-forward zone Z2. Detailed illustrations are omitted, but in this embodiment, similar to the first sensor 35, the second sensor 40 and the third sensor 42 are photoelectric sensors having a light-emitting unit and a light-receiving unit. In the following description, similar to the first sensor 35, the state in which the light-receiving unit is not receiving light from the light-emitting unit is referred to as the "OFF state," and the state in which the light-receiving unit is receiving light from the light-emitting unit is referred to as the "ON state."

[0036] As shown in Figure 5, the control device 60 is communicatively connected to the first sensor 35, the second sensor 40, the third sensor 42, and the drive unit 25. The control device 60 may be connected to these devices by wire or by wireless connection. The control device 60 may consist of a computer comprising a communication interface, storage, memory, and a processor. The communication interface is an interface for sending and receiving data with devices such as the first sensor 35, the second sensor 40, the third sensor 42, and the drive unit 25. Various programs and various data are stored in the storage. Programs and data necessary for the processor to perform various processes are temporarily stored in the memory. The memory operates as the processor's work area. The control device 60 comprises an input unit 61, a determination unit 62, a position determination unit 63, and a drive control unit 64.

[0037] Figure 6 is a schematic diagram illustrating an example of control by the control device 60. Figure 6 shows the control when an object to be processed 5 is being transported such that its size L1 is L1 ≤ D2.

[0038] The input unit 61 receives the size L1 of the object to be processed 5 along the transport direction. The size L1 of the object to be processed 5 may be input by the user, for example. In this case, it is preferable that the continuous heating furnace 1 is configured so that the heating of the object to be processed 5 starts after the size L1 of the object to be processed 5 has been input to the control device 60 by the user.

[0039] The determining unit 62 executes processing for respectively determining the conveying speeds of the plurality of drive divided zones SZ1 and SZ2 based on the size L1 of the workpiece 5 along the conveying direction. In this embodiment, the determining unit 62 determines the conveying speeds of the first drive divided zone SZ1 and the second drive divided zone SZ2 based on the size L1 of the workpiece 5 input to the input unit 61. In this embodiment, the determining unit 62 executes the above processing based on the magnitude relationship between the size L1 of the workpiece 5 and the distances D1 and D2. In this embodiment, when L1>D1, the determining unit 62 determines the conveying speeds of all the drive divided zones SZ1 and SZ2 as a second conveying speed V2. When D2<L1≤D1, the determining unit 62 determines the conveying speed of the first drive divided zone SZ1 as a first conveying speed V1, and determines the conveying speed of the second drive divided zone SZ2 as the second conveying speed V2. When L1≤D2, the determining unit 62 determines the conveying speeds of all the drive divided zones SZ1 and SZ2 as the first conveying speed V1. In the embodiment shown in FIG. 6, since L1≤D2, the determining unit 62 determines the conveying speeds of all the drive divided zones SZ1 and SZ2 as the first conveying speed V1. It should be noted that the values of the distances D1 and D2 are preferably stored in the control device 60 in advance.

[0040] The position determining unit 63 executes processing for determining whether the rear end of the workpiece 5 has moved into the first drive divided zone SZ1 based on the detection result of the first sensor 35. The position determining unit 63 executes processing for determining whether the rear end of the workpiece 5 has moved into the second drive divided zone SZ2 based on the detection result of the second sensor 40. The position determining unit 63 executes processing for determining whether the rear end of the workpiece 5 has moved into the fast-forward zone Z2 based on the detection result of the third sensor 42.

[0041] In this embodiment, when the object to be processed 5 passes through boundary B0, the first sensor 35 transitions from ON state to OFF state and then back to ON state. When the first sensor 35 transitions from ON state to OFF state, the front end of the object to be processed 5 is located at boundary B0. When the first sensor 35 transitions from OFF state to ON state, the rear end of the object to be processed 5 is located at boundary B0. When the first sensor 35 transitions from OFF state to ON state, the rear end of the object to be processed 5 moves onto the first drive division zone SZ1. In this embodiment, the position determination unit 63 determines whether the rear end of the object to be processed 5 has moved onto the first drive division zone SZ1 by determining whether the first sensor 35 has transitioned from OFF state to ON state.

[0042] Similarly, in this embodiment, the position determination unit 63 determines whether the rear end of the workpiece 5 has moved into the second drive division zone SZ2 by determining whether the second sensor 40 has changed from an OFF state to an ON state. The position determination unit 63 determines whether the rear end of the workpiece 5 has moved into the rapid traverse zone Z2 by determining whether the third sensor 42 has changed from an OFF state to an ON state.

[0043] The drive control unit 64 controls the operation of the drive devices 25R, 25a, 25b, and 25c based on the results of the processing performed by the determination unit 62 and the position determination unit 63. The drive control unit 64 controls the drive device 25 to transport the workpiece 5 at the transport speed determined by the determination unit 62. In the configuration shown in Figure 6, since L1 ≤ D2, the drive control unit 64 transports the workpiece 5 at the first transport speed V1 in the first drive division zone SZ1 and the second drive division zone SZ2.

[0044] Furthermore, in this embodiment, the drive control unit 64 determines the timing for increasing the transport speed of the workpiece 5 from the first transport speed V1 to the second transport speed V2 based on the results of the first sensor 35, the second sensor 40, and the third sensor 42.

[0045] In the form shown in Fig. 6, since L1 ≤ D2, the control device 60 determines the conveying speed of all driving division zones SZ1 and SZ2 as the first conveying speed V1. Therefore, the only zone where the object 5 to be processed is conveyed at the second conveying speed V2 is the fast-forward zone Z2. In this case, based on the detection result of the third sensor 42, the control device 60 determines the timing for increasing the conveying speed of the object 5 to be processed such that the conveying speed of the object 5 to be processed increases after the object 5 to be processed moves onto the fast-forward zone Z2. Accordingly, when a part of the object 5 to be processed is located in the second driving division zone SZ2, the object 5 to be processed is conveyed at the first conveying speed V1. Then, after the rear end of the object 5 to be processed moves onto the fast-forward zone Z2, the object 5 to be processed is conveyed at the second conveying speed V2.

[0046] Figs. 7 and 8 are diagrams schematically showing other examples of control by the control device 60. Fig. 7 shows the control when the object 5 to be processed, whose dimension L1 satisfies D2 < L1 ≤ D1, is being conveyed. Fig. 8 shows the control when the object 5 to be processed, whose dimension L1 satisfies L1 > D1, is being conveyed.

[0047] In the form shown in Fig. 7, the control device 60 determines the conveying speed of the first driving division zone SZ1, which is located upstream of the second sensor 40 in the conveying direction, as the first conveying speed V1, and determines the conveying speed of the second driving division zone SZ2, which is located downstream of the second sensor 40 in the conveying direction, as the second conveying speed V2. In this case, based on the detection result of the second sensor 40, the control device 60 determines the timing for increasing the conveying speed of the object 5 to be processed such that the conveying speed of the object 5 to be processed increases after the object 5 to be processed moves onto the second driving division zone SZ2, which is downstream of the second sensor 40 in the conveying direction. Accordingly, when a part of the object 5 to be processed is located in the first driving division zone SZ1, the object 5 to be processed is conveyed at the first conveying speed V1. Then, after the rear end of the object 5 to be processed moves onto the second driving division zone SZ2, the object 5 to be processed is conveyed at the second conveying speed V2.

[0048] In the configuration shown in Figure 8, since L1 > D1, the control device 60 determines the transport speed of all drive division zones SZ1 and SZ2 to be the second transport speed V2. In this case, based on the detection result of the first sensor 35, the control device 60 determines the timing to increase the transport speed of the workpiece 5 so that the transport speed of the workpiece 5 increases after the workpiece 5 has moved into the first drive division zone SZ1. As a result, when a part of the workpiece 5 is located in the constant speed zone Z1, the workpiece 5 is transported at the first transport speed V1. Then, after the rear end of the workpiece 5 has moved into the first drive division zone SZ1, the workpiece 5 is transported at the second transport speed V2.

[0049] The continuous heating furnace 1 according to the above-described embodiment comprises a furnace body 10, a plurality of transport rollers 22, a drive device 25, and a control device 60. The furnace body 10 is formed in the shape of a tunnel. The furnace body 10 encloses a transport space 10a for transporting the workpiece 5 along a predetermined transport path. The plurality of transport rollers 22 are arranged along the transport direction. The drive device 25 rotates the plurality of transport rollers 22. The transport path is divided into a constant speed zone Z1, a plurality of drive division zones SZ1 and SZ2, and a rapid traverse zone Z2. In the constant speed zone Z1, the plurality of transport rollers 22 rotate at a predetermined rotational speed. The plurality of drive division zones SZ1 and SZ2 are provided continuously with the constant speed zone Z1. The rapid traverse zone Z2 is provided continuously with the plurality of drive division zones SZ1 and SZ2. In the rapid traverse zone Z2, the rotational speed of the plurality of transport rollers 22 is configured to be faster than in the constant speed zone Z1. The drive unit 25 is provided in the constant speed zone Z1, the multiple drive division zones SZ1 and SZ2, and the rapid traverse zone Z2. In the constant speed zone Z1, the workpiece 5 is transported at a predetermined first transport speed V1. In the rapid traverse zone Z2, the workpiece 5 is transported at a second transport speed V2. The control device 60 is configured to determine the transport speeds of the multiple drive division zones SZ1 and SZ2 based on the size L1 of the workpiece 5 along the transport direction.

[0050] In this continuous heating furnace 1, multiple drive division zones SZ1 and SZ2 are provided between the constant speed zone Z1 and the rapid traverse zone Z2. The transport speeds of the drive division zones SZ1 and SZ2 are determined according to the size L1 of the workpiece 5. For example, depending on the size L1 of the workpiece 5, the multiple drive division zones SZ1 and SZ2 can switch at an appropriate position from a first transport speed V1, which is the transport speed of the constant speed zone Z1, to a second transport speed V2, which is the transport speed of the rapid traverse zone Z2. Therefore, even when processing multiple types of workpieces 5 with different dimensions, each workpiece 5 can be heated more appropriately. For this reason, the continuous heating furnace 1 is highly versatile.

[0051] According to the above-described embodiment, the furnace body 10 has an inlet 11a and an outlet 11b. The inlet 11a is an opening for loading the workpiece 5 into the transport space 10a. The outlet 11b is an opening for unloading the workpiece 5 from the transport space 10a. The boundary B2 between the second drive division zone SZ2 and the rapid traverse zone Z2 is provided on the outlet 11b side of the furnace body 10. According to the above-described embodiment, for example, when the continuous heating furnace 1 is a furnace used for hot press processing of a workpiece 5, the workpiece 5 can be unloaded from the furnace body 10 at high speed from a position corresponding to the size L1 of the workpiece 5. Therefore, hot press processing can be appropriately performed on multiple types of workpieces 5 with different sizes L1 along the transport direction.

[0052] According to the above embodiment, the discharge port 11b is located within the range of the rapid traverse zone Z2. According to the above embodiment, the workpiece 5 can be transported at high speed before the front end of the workpiece 5 extends outside the furnace body 10. This makes it possible to suppress the temperature drop of the workpiece 5 when it is discharged.

[0053] According to the above embodiment, the conveying path is divided into a constant speed zone Z1, two drive division zones SZ1 and SZ2, and a fast-forward zone Z2. When the size L1 of the workpiece 5 satisfies L1>D1, the control device 60 sets the conveying speed of all the drive division zones SZ1 and SZ2 to a second conveying speed V2. When the size L1 of the workpiece 5 satisfies D2<L1≦D1, the control device 60 sets the conveying speed of the first drive division zone SZ1 to a first conveying speed V1, and sets the conveying speed of the second drive division zone SZ2 to the second conveying speed V2. When the size L1 of the workpiece 5 satisfies L1≦D2, the control device 60 sets the conveying speed of all the drive division zones SZ1 and SZ2 to the first conveying speed V1.

[0054] According to this configuration, the workpiece 5 can be conveyed at high speed before the front end of the workpiece 5 protrudes out of the furnace body 10. Thereby, temperature reduction of the workpiece 5 when the workpiece 5 is carried out can be suppressed. Further, according to the above configuration, it is possible to prevent the workpiece 5 from being conveyed at high speed in an excessively long range with respect to the size L1 along the conveying direction of the workpiece 5. Therefore, for a plurality of types of workpieces 5 having mutually different sizes L1 along the conveying direction, the workpiece 5 can be carried out at high speed while effectively utilizing the space inside the furnace body 10.

[0055] According to the above embodiment, the continuous heating furnace 1 is provided with a first sensor 35. The first sensor 35 detects whether or not the workpiece 5 is positioned at the boundary B0 between the constant speed zone Z1 and the first drive division zone SZ1. When it is determined that the conveying speed of all the drive division zones SZ1 and SZ2 is the second conveying speed V2, the control device 60 is configured to, based on the detection result of the first sensor 35, determine the timing for increasing the conveying speed of the workpiece 5 such that the conveying speed of the workpiece 5 increases after the workpiece 5 has moved into the first drive division zone SZ1. This makes it difficult for conveying troubles caused by changing the conveying speed of the workpiece 5 to occur.

[0056] According to the embodiment described above, the continuous heating furnace 1 is equipped with a second sensor 40. The second sensor 40 detects whether or not the workpiece 5 is located at the boundary B1 between the first drive division zone SZ1 and the second drive division zone SZ2. When the transport speed of the first drive division zone SZ1 is determined to be the first transport speed V1 and the transport speed of the second drive division zone SZ2 is determined to be the second transport speed V2, the control device 60 is configured to determine the timing for increasing the transport speed of the workpiece 5 based on the detection result of the second sensor 40, so that the transport speed of the workpiece 5 increases after it has moved into the second drive division zone SZ2. This makes it less likely for transport problems to occur due to changes in the transport speed of the workpiece 5.

[0057] According to the above-described embodiment, the continuous heating furnace 1 is equipped with a third sensor 42. The third sensor 42 detects whether or not the workpiece 5 is located at the boundary B2 between the second drive division zone SZ2 and the rapid traverse zone Z2. When the transport speeds of all drive division zones SZ1 and SZ2 are determined to be the first transport speed V1, the control device 60 is configured to determine the timing for increasing the transport speed of the workpiece 5 based on the detection result of the third sensor 42, so that the transport speed of the workpiece 5 increases after it has moved into the rapid traverse zone Z2. This makes it less likely for transport problems to occur due to changes in the transport speed of the workpiece 5.

[0058] Incidentally, according to the inventor's findings, for example, when the size L1 of the workpiece 5 is L1 > D1, it is preferable that the rear end of the preceding workpiece 5 moves into the second drive division zone SZ2 before the front end of the subsequent workpiece 5 reaches the first drive division zone SZ1. According to the inventor's findings, if the front end of the subsequent workpiece 5 reaches the first drive division zone SZ1 before the rear end of the preceding workpiece 5 moves into the second drive division zone SZ2, transport problems are likely to occur with the subsequent workpiece 5.

[0059] However, according to the above-described embodiment, the lengths of the drive divided zones SZ1 and SZ2 increase in order from the drive divided zone on the downstream side in the conveyance direction. According to this configuration, before the front end of the subsequent workpiece 5 reaches the first drive divided zone SZ1, the rear end of the preceding workpiece 5 is more likely to move onto the second drive divided zone SZ2, so conveyance troubles are less likely to occur. Similarly, even when the length L1 of the workpiece 5 satisfies D2 < L1 ≤ D1, before the front end of the subsequent workpiece 5 reaches the second drive divided zone SZ2, the rear end of the preceding workpiece 5 is more likely to move onto the fast-forward zone Z2, so conveyance troubles are less likely to occur.

[0060] In the above-described embodiment, two drive divided zones SZ1 and SZ2 are set on the conveyance path. However, n drive divided zones may be set on the conveyance path. Here, n is a natural number satisfying n ≥ 2. For example, let L1 be the length of the workpiece 5 along the conveyance direction, and let D be the distance between the downstream end in the conveyance direction of the m-th drive divided zone counted from the upstream side in the conveyance direction (m is a natural number satisfying m ≤ n) and the carry-out port 11b m In this case, when L1 > D1, the control device 60 may set the conveyance speed of all drive divided zones to the second conveyance speed V2. The control device 60 sets D k+1 < L1 ≤ D k (where k is a natural number satisfying 1 ≤ k ≤ n-1), the conveyance speed of the drive divided zones located at the k-th position and below counted from the upstream side in the conveyance direction may be set to the first conveyance speed V1, and the conveyance speed of the drive divided zones located at the (k+1)-th position and above counted from the upstream side in the conveyance direction may be set to the second conveyance speed V2. When L1 ≤ D n the conveyance speed of all drive divided zones may be set to the first conveyance speed V1. When n drive divided zones are set on the conveyance path, the continuous heating furnace 1 is preferably provided with (n-1) pieces of the second sensor 40.

[0061] One embodiment of the technology proposed herein has been described above. However, the above-described embodiment is merely an example, and the technology can be implemented in other aspects.

[0062] In the above-described embodiment, the rapid traverse zone Z2 was located in front of the constant speed zone Z1, but the position of the rapid traverse zone Z2 is not limited to this. The rapid traverse zone Z2 may be located behind the constant speed zone Z1. In this case, the multiple drive division zones may be located in front of the rapid traverse zone Z2 and behind the constant speed zone Z1. In this case, the loading entrance 11a may be located within the rapid traverse zone Z2. Also, in this case, if multiple drive division zones are set in the transport path, the lengths of the multiple drive division zones may increase in order from the drive division zone on the upstream side in the transport direction.

[0063] The rapid traverse zone Z2 may be located in front of and behind the constant speed zone Z1. That is, the constant speed zone Z1 may be located between two rapid traverse zones Z2. In this case, multiple drive division zones may be located between the constant speed zone Z1 and the rapid traverse zone Z2. For example, the transport path may be divided in the following order from the upstream side in the transport direction: rapid traverse zone Z2, multiple drive division zones, constant speed zone Z1, multiple drive division zones, rapid traverse zone Z2. Also, the rapid traverse zone Z2 may be located between two constant speed zones Z1. In this case, the rapid traverse zone Z2 may be located in the central part of the furnace body 10 in the front-rear direction. For example, the transport path may be divided in the following order from the upstream side in the transport direction: constant speed zone Z1, multiple drive division zones, rapid traverse zone Z2, multiple drive division zones, constant speed zone Z1.

[0064] Thus, the positional relationship between the constant-speed zone Z1 and the rapid-forward zone Z2 is not particularly limited. The positional relationship between the constant-speed zone Z1 and the rapid-forward zone Z2 can be appropriately set depending on the application of the continuous heating furnace 1. It is preferable that multiple drive division zones be arranged between the constant-speed zone Z1 and the rapid-forward zone Z2.

[0065] In the above-described embodiment, the continuous heating furnace 1 was equipped with a first sensor 35, a second sensor 40, and a third sensor 42. However, the continuous heating furnace 1 does not need to be equipped with at least one of the first sensor 35, the second sensor 40, and the third sensor 42. For example, if the continuous heating furnace 1 is not equipped with all three sensors, the timing for increasing the transport speed of the workpiece 5 may be predetermined. The timing for increasing the transport speed of the workpiece 5 may be set, for example, based on the elapsed time since the start of the heating treatment of the workpiece 5. Also, for example, if the continuous heating furnace 1 is equipped with the first sensor 35 and the second sensor 40 but not the third sensor 42, when detecting whether the workpiece 5 is located at boundary B2, the detection of whether the workpiece 5 is located at boundary B2 may be based on the time since the workpiece 5 was detected by the first sensor 35.

[0066] In the above-described embodiment, the continuous heating furnace 1 was configured such that the lengths of the multiple drive division zones SZ1 and SZ2 increased sequentially from the drive division zone on the downstream side in the conveying direction. However, the relative sizes of the multiple drive division zones SZ1 and SZ2 are not limited to this. For example, if the length of the second drive division zone SZ2 is X2 and the length of the first drive division zone SZ1 is X1, the continuous heating furnace 1 may be configured such that X2 ≤ X1.

[0067] In the above-described embodiment, the size L1 of the object to be processed 5 was input by the user, but the method by which the control device 60 acquires information regarding the size of the object to be processed 5 is not limited to this. For example, the control device 60 may acquire the size L1 of the object to be processed 5 by inputting the size L1 of the object to be processed 5 measured by a sensor provided in the continuous heating furnace 1 to the control device 60. In this case, the control device 60 does not need to have an input unit 61. As this sensor, for example, an optical sensor that measures the dimensions of an object by irradiating it with laser light may be used. This sensor is preferably positioned behind the furnace body 10 and configured to measure the size L1 of the object to be processed 5 before the object to be processed 5 is brought into the furnace body 10.

[0068] The technologies disclosed herein have been described in detail above. Unless otherwise specified, the embodiments and other details mentioned herein do not limit the present invention. Furthermore, the technologies disclosed herein can be modified in various ways, and each component and each process mentioned herein may be omitted or combined as appropriate, unless no particular problems arise. This specification also includes the disclosures described in the following sections.

[0069] Section 1: A tunnel-shaped furnace body enclosing a transport space for transporting materials along a predetermined transport route, A plurality of conveying rollers arranged along the conveying path of the workpiece, Multiple drive devices for rotating the multiple transport rollers, Control device and Equipped with, The aforementioned transport path is The aforementioned multiple conveying rollers rotate at a predetermined rotational speed in a constant speed zone, Multiple drive division zones are provided continuously with the constant speed zone, A rapid traverse zone is provided in continuity with the plurality of drive division zones, and the rotation speed of the plurality of transport rollers is faster than that of the constant speed zone. It is divided into the following categories: The drive device is The constant speed zone, the plurality of drive division zones, and the rapid traverse zone are each provided with the following: In the constant-speed zone, the workpiece is transported at a predetermined first transport speed. In the rapid-forward zone, the workpiece is transported at a second transport speed that is faster than the first transport speed. The control device is A continuous heating furnace configured to determine the transport speed of each of the plurality of drive division zones based on the size of the workpiece along the transport direction.

[0070] Section 2: The aforementioned furnace body is An entrance for transporting the object to be processed into the transport space, An outlet for unloading the processed object from the transport space. It has, The continuous heating furnace according to item 1, wherein a boundary between the drive division zone and the rapid feed zone is provided on the outlet side of the furnace body.

[0071] Section 3: The continuous heating furnace according to item 2, wherein the discharge port is located within the range of the rapid-forward zone.

[0072] Section 4: The continuous heating furnace according to claim 2 or 3, wherein the lengths of the plurality of drive division zones are progressively larger from the drive division zone downstream in the conveying direction.

[0073] Section 5: The transport path is divided into the constant speed zone, n drive division zones (where n is a natural number satisfying n≧2), and the rapid traverse zone. L1 is the size of the object to be processed along the transport direction, and D is the distance between the downstream end of the drive division zone located at the mth position (where m is a natural number satisfying m ≤ n) from the upstream side in the transport direction and the discharge port. m In that case, The control device is If L1 > D1, the transport speed of all the drive division zones is determined to be the second transport speed. D k+1 <L1≦D k If k is a natural number satisfying 1 ≤ k ≤ n-1, the transport speed of the drive division zones located k or less from the upstream side in the transport direction is determined as the first transport speed, and the transport speed of the drive division zones located (k+1) or more from the upstream side in the transport direction is determined as the second transport speed. L1≦D n In the case of a continuous heating furnace according to any one of items 2 to 4, the transport speed of all the drive division zones is determined to be the first transport speed.

[0074] Item 6: A first sensor is provided to detect whether or not the workpiece is located at the boundary between the constant speed zone and the drive division zone. When the control device determines that the transport speed of all the drive division zones is the second transport speed, The control device is A continuous heating furnace according to any one of claims 2 to 5, configured to determine the timing for increasing the transport speed of the workpiece after the workpiece has moved onto the drive division zone, based on the detection result of the first sensor.

[0075] Section 7: The system includes a second sensor that detects whether or not the workpiece is located at the boundary between adjacent drive division zones among the plurality of drive division zones, When the control device determines the transport speed of the drive division zone located downstream of the second sensor in the transport direction as the second transport speed, and determines the transport speed of the drive division zone located upstream of the second sensor in the transport direction as the first transport speed, The control device is A continuous heating furnace according to any one of claims 2 to 6, wherein the furnace is configured to determine the timing for increasing the transport speed of the workpiece after the workpiece has moved onto the drive division zone located downstream of the second sensor in the transport direction, based on the detection result of the second sensor.

[0076] Section 8: A third sensor is provided to detect whether or not the workpiece is located at the boundary between the drive division zone and the rapid traverse zone. When the control device determines that the transport speed of all the drive division zones is the first transport speed, The control device is A continuous heating furnace according to any one of claims 2 to 7, configured to determine the timing for increasing the transport speed of the workpiece after the workpiece has moved into the rapid transport zone, based on the detection result of the third sensor.

[0077] Section 9: The control device is A continuous heating furnace according to any one of claims 1 to 8, comprising an input unit for inputting the size of the workpiece along the transport direction. [Explanation of symbols]

[0078] 1. Continuous heating furnace 5. Items to be processed 10 Furnace body 10a Conveying space 11a Loading entrance 11b Exit 22 Conveyor rollers 25 Drive unit 35 First Sensor 40. Second Sensor 42 Third Sensor 60 Control device 61 Input section Z1 Constant Speed ​​Zone Z2 Fast Forward Zone SZ1 Drive Split Zone (First Drive Split Zone) SZ2 Drive Split Zone (Second Drive Split Zone) V1 First conveying speed V2 Second transport speed

Claims

1. A tunnel-shaped furnace body enclosing a transport space for transporting materials along a predetermined transport route, A plurality of conveying rollers arranged along the conveying path of the workpiece, Multiple drive devices for rotating the multiple transport rollers, Control device and Equipped with, The aforementioned transport path is The aforementioned multiple conveying rollers rotate at a predetermined rotational speed in a constant speed zone, Multiple drive division zones are provided continuously with the constant speed zone, A rapid traverse zone is provided in continuity with the aforementioned multiple drive division zones, and the rotation speed of the multiple transport rollers is faster than that of the constant speed zone. It is divided into the following categories: The drive device is The constant speed zone, the plurality of drive division zones, and the rapid traverse zone are each provided with the following: In the constant-speed zone, the workpiece is transported at a predetermined first transport speed. In the rapid-forward zone, the workpiece is transported at a second transport speed that is faster than the first transport speed. The control device is A continuous heating furnace configured to determine the transport speed of each of the plurality of drive division zones based on the size of the workpiece along the transport direction.

2. The aforementioned furnace body is An entrance for transporting the object to be processed into the transport space, An outlet for unloading the processed object from the transport space. It has, The continuous heating furnace according to claim 1, wherein a boundary between the drive division zone and the rapid feed zone is provided on the outlet side of the furnace body.

3. The continuous heating furnace according to claim 2, wherein the discharge port is located within the range of the rapid-forward zone.

4. The continuous heating furnace according to claim 2, wherein the lengths of the plurality of drive division zones are progressively larger from the drive division zone downstream in the conveying direction.

5. The transport path is divided into the constant speed zone, n drive division zones (where n is a natural number satisfying n≧2), and the rapid traverse zone. L1 is the size of the object to be processed along the transport direction, and D is the distance between the downstream end of the drive division zone located at the mth position (where m is a natural number satisfying m ≤ n) from the upstream side in the transport direction and the discharge port. ｍ In that case, The control device is L1>D １ In this case, the transport speed of all the drive division zones is determined to be the second transport speed. D ｋ＋１ <L1≦D ｋ In the case where k is a natural number satisfying 1 ≤ k ≤ n-1, the transport speed of the drive division zones located k or less from the upstream side in the transport direction is determined as the first transport speed, and the transport speed of the drive division zones located (k+1) or more from the upstream side in the transport direction is determined as the second transport speed. L1 ≤ D ｎ In this case, the continuous heating furnace according to claim 2, wherein the transport speed of all the drive division zones is determined to be the first transport speed.

6. A first sensor is provided to detect whether or not the workpiece is located at the boundary between the constant speed zone and the drive division zone. When the control device determines that the transport speed of all the drive division zones is the second transport speed, The control device is The continuous heating furnace according to claim 2, configured to determine the timing for increasing the transport speed of the workpiece after the workpiece has moved onto the drive division zone, based on the detection result of the first sensor.

7. The system includes a second sensor for detecting whether the workpiece is located at the boundary between adjacent drive division zones among the plurality of drive division zones, When the control device determines the transport speed of the drive division zone located downstream of the second sensor in the transport direction as the second transport speed, and determines the transport speed of the drive division zone located upstream of the second sensor in the transport direction as the first transport speed, The control device is The continuous heating furnace according to claim 2, wherein the system is configured to determine the timing for increasing the transport speed of the workpiece after the workpiece has moved onto the drive division zone located downstream of the second sensor in the transport direction, based on the detection result of the second sensor, so that the transport speed of the workpiece increases.

8. A third sensor is provided to detect whether or not the workpiece is located at the boundary between the drive division zone and the rapid traverse zone. When the control device determines that the transport speed of all the drive division zones is the first transport speed, The control device is The continuous heating furnace according to claim 2, configured to determine the timing for increasing the transport speed of the workpiece after the workpiece has moved into the rapid-forward zone, based on the detection result of the third sensor.

9. The control device is The continuous heating furnace according to claim 1, further comprising an input unit for inputting the size of the object to be processed along the conveying direction.

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