Continuous heating furnace

Abstract

To improve maintainability.SOLUTION: A continuous heating furnace 1 comprises: a tunnel-shaped furnace body 10; plural transport rollers 20 arrayed in a transport direction; a drive mechanism 40 that drives the plural transport rollers 20; and a follower mechanism 60 that supports the plural transport rollers. The drive mechanism 40 includes: plural drive shafts 43 that correspond one-to-one to the plural transport rollers 20 and are inserted respectively into a hollow part of a corresponding transport roller 20; a power transmission mechanism 40A to which the plural drive shafts 43 are connected; and a drive device connected to the power transmission mechanism 40A. In at least a part of the plural drive shafts 43, insert ends 43d that are respectively inserted into the hollow parts of the transport rollers 20 are made sharp in a spindle shape.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a continuous furnace. [Background technology]

[0002] JP 2019-172436 A discloses an invention related to a continuous heating furnace. The continuous heating furnace disclosed in the publication includes a furnace body having a tunnel-shaped furnace chamber and a plurality of conveying rollers. A plurality of through holes are formed in the side wall of the furnace body. The plurality of conveying rollers are each a cylindrical member, and are arranged at a predetermined interval in the longitudinal direction of the furnace body in a parallel state through a plurality of through holes formed in the side wall of the furnace body. The ends of the plurality of conveying rollers protrude from the side wall of the furnace body. The ends of the plurality of conveying rollers are fitted with the tips of support shafts rotatably supported on the outside of the side wall of the furnace body. As a result, the plurality of conveying rollers are each rotatably supported.

[0003] In the publication, the support shaft includes a small diameter shaft portion and a roller support end portion that is larger in diameter than the small diameter shaft portion at the tip side of the small diameter shaft portion and receives the inner peripheral surface of the end portion of the conveying roller. The publication discloses that when the support shaft and the conveying roller are concentric, the width of the annular support surface of the roller support end portion that receives the inner peripheral surface of the end portion of the conveying roller is 5 mm or less in the central axis direction. The publication also discloses that the outer peripheral surface of the roller support end portion is formed by a spherical surface, that it is formed by a curved surface having a radius of curvature shorter than the maximum diameter of the roller support end portion in a cross section passing through the central axis of the roller support end portion, that it has a cylindrical surface parallel to the central axis of the roller support end portion, and that the entire cylindrical surface constitutes the annular support surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-172436 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the present inventors would like to improve the ease of maintenance of such a continuous heating furnace. [Means for solving the problem]

[0006] The continuous heating furnace disclosed herein comprises a tunnel-shaped furnace body enclosing a space along the conveying direction, a plurality of conveying rollers each crossing the tunnel-shaped furnace body and arranged along the conveying direction, a drive mechanism arranged on one side of the width of the furnace body for driving the plurality of conveying rollers, and a driven mechanism arranged on the other side of the width of the furnace body for supporting the plurality of conveying rollers. Here, each of the multiple conveying rollers is a hollow shaft member. The drive mechanism includes multiple drive shafts that correspond one-to-one to the multiple conveying rollers and are inserted into the hollow portion of the corresponding one of the conveying rollers, a power transmission mechanism to which the multiple drive shafts are connected, and a drive device connected to the power transmission mechanism. The driven mechanism is disposed on the other side of the width direction of the furnace body and includes multiple driven shafts that are each inserted into the hollow portion of a corresponding one of the multiple conveying rollers. At least some of the multiple drive shafts have insertion ends that are inserted into the hollow portion of the conveying roller that are each pointed in a cone shape.

[0007] According to this continuous heating furnace, the transport roller can be attached to the drive shaft by pushing it in from the driven mechanism side, which makes it easier to attach the transport roller to the furnace body and improves maintainability. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a vertical cross-sectional side view of a continuous heating furnace 1. [Diagram 2] FIG. 2 is a side view of the continuous heating furnace 1. [Diagram 3] FIG. 3 is a cross-sectional front view of the continuous heating furnace 1 taken along a cross section perpendicular to the conveying direction. [Figure 4]FIG. 4 is a schematic diagram showing a support structure of the transport roller 20 on the drive side. [Diagram 5] FIG. 5 is a schematic diagram showing a support structure of the driven side of the transport roller 20. As shown in FIG. [Figure 6] FIG. 6 is a side view of the insertion end 43d of the drive shaft 43. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An embodiment of the present disclosure will be described below. In the drawings, members and parts that perform the same function are appropriately denoted with the same reference numerals. Furthermore, the dimensional relationships (length, width, thickness, etc.) in each drawing do not reflect the actual dimensional relationships. Unless otherwise specified, the present invention is not limited to the embodiment disclosed herein. In this specification, the notation "X to Y" indicating a numerical range means "X or more and Y or less" unless otherwise specified.

[0010] In each figure, the directions of up, down, left, right, front, and rear are appropriately indicated by arrows U, D, L, R, F, and Rr in the figure. The directions of up, down, left, right, front, and rear are determined merely for convenience of explanation. The front and rear of the continuous heating furnace 1 disclosed here are determined along the conveying direction of the continuous heating furnace 1, and the front of the conveying direction is the "front (F)" and the rear of the conveying direction is the "rear (Rr)". The inlet through which the workpiece is introduced into the continuous heating furnace 1 is provided on the rear side (Rr side) of the conveying direction. The outlet through which the workpiece is discharged from the continuous heating furnace 1 is provided on the front side (F side) of the conveying direction. In addition, the left side facing the front side (F side) of the conveying direction is the left (L), and the right side is the right (R).

[0011] FIG. 1 is a vertical cross-sectional side view of a continuous heating furnace 1. FIG. 1 shows a schematic right side view of the continuous heating furnace 1 vertically cut along the conveying direction. FIG. 2 is a side view of the continuous heating furnace 1. FIG. 2 shows the driving side (left side) of the sides of the continuous heating furnace 1. FIG. 3 is a cross-sectional front view of the continuous heating furnace 1 taken along a cross section perpendicular to the conveying direction.

[0012] <Continuous heating furnace 1> As shown in Figs. 1 to 3, the continuous heating furnace 1 includes a furnace body 10, a plurality of conveying rollers 20, a driving mechanism 40, and a driven mechanism 60. The continuous heating furnace 1 is a heating furnace that continuously heats the workpiece A while conveying it along the conveying direction. The continuous heating furnace 1 is a so-called roller hearth kiln that heats the workpiece A while conveying it in the conveying direction (from the rear Rr to the front F) by the rotation of the conveying rollers. The arrow in the figure indicates the conveying direction in which the workpiece A is conveyed. In this embodiment, as shown in Fig. 3, the driving mechanism 40 is provided on the left side (L side) of the furnace body 10 toward the front side (F side) of the conveying direction. The driven mechanism 60 is provided on the right side (R side) of the furnace body 10 toward the front side (F side) of the conveying direction.

[0013] <Furnace body 10> As shown in Fig. 1, the furnace body 10 is tunnel-shaped and encloses a space 10a along the transport direction in which the workpiece A is transported. In this embodiment, the furnace body 10 has a side wall 11, a side wall 12 (see Fig. 6), a bottom wall 13, and a ceiling wall 14. A plurality of transport rollers 20 and a heater 30 are provided in the space 10a inside the furnace body 10.

[0014] The heater 30 is a facility for heat-treating the workpiece A transported on the transport rollers 20. In this embodiment, a cylindrical ceramic heater is used as the heater 30. The heaters 30 are arranged above and below the multiple transport rollers 20 at a predetermined interval along the transport direction. The heaters 30 are hung across the side walls 11 and 12. The heaters 30 are not particularly limited as long as they can heat the workpiece A. By changing the number, output, etc. of the heaters 30, the workpiece A can be processed under different processing conditions along the transport direction. Although not shown, a temperature sensor may be provided in the space 10a. Furthermore, although not shown, a pipe for supplying an atmospheric gas may be connected to the space 10a.

[0015] The furnace body 10 is made of a material that insulates the heat of the space 10a and has fire resistance. The furnace body 10 can be made of an insulating material in which ceramic fiber boards formed into a predetermined shape are stacked in the thickness direction. The ceramic fiber board is, for example, a plate material formed into a plate shape by adding inorganic filler and inorganic / organic binder to so-called bulk fiber. The furnace body 10 may be made of heat-resistant bricks. The thickness of the furnace body 10 is set to a required thickness that sufficiently insulates the heat of the space 10a. The outside of the furnace body 10 is covered with an outer wall 16. The outer wall 16 is made of a metal material that is excellent in rigidity and heat resistance. For example, stainless steel or the like can be used as the outer wall 16. As shown in FIG. 3, a plurality of through holes 11a, 12a are formed in the side walls 11, 12 of the furnace body 10. In the side walls 11, 12 of the furnace body 10, the plurality of through holes 11a, 12a face each other in the width direction. In addition, the multiple through holes 11a, 12a are formed in the side walls 11, 12 of the furnace body 10 so as to be aligned at approximately the same height at predetermined intervals along the conveying direction. The furnace body 10 as a whole is preferably installed on a frame 10b serving as a base.

[0016] The continuous heating furnace 1 may be a so-called atmospheric furnace in which the inlet for carrying the workpiece A and the outlet for carrying the workpiece A are open to the atmosphere. The continuous heating furnace 1 may be a so-called atmospheric furnace in which the atmospheric gas in the furnace body is adjusted. The furnace body may be provided with a gas supply pipe and a gas exhaust pipe. The gas supply pipe is a pipe for supplying the atmospheric gas into the furnace body. A gas cylinder for supplying the atmospheric gas may be connected to the gas supply pipe. Although not particularly limited, for example, nitrogen, argon, air, oxygen, carbon dioxide, hydrogen, etc. may be used as the atmospheric gas. The atmospheric gas is appropriately selected according to the heating conditions of the workpiece, etc. The gas exhaust pipe is a pipe for exhausting the atmospheric gas from the furnace body. An exhaust device such as an exhaust pump may be connected to the gas exhaust pipe. When a reaction gas is generated from the workpiece, the reaction gas is exhausted from the gas exhaust pipe. By providing the gas supply pipe and the gas exhaust pipe in the furnace body 10, the atmosphere in the furnace body can be adjusted. Furthermore, within the furnace body 10, partitions may be provided that divide the space 10a into regions along the conveying direction.

[0017] <Multiple conveying rollers 20> The multiple transport rollers 20 each cross the tunnel-shaped furnace body 10. The multiple transport rollers 20 are arranged in the transport direction. The multiple transport rollers 20 are each a hollow shaft member. In this embodiment, the transport rollers 20 are cylindrical rollers having a required length that can cross the furnace body 10. For example, a ceramic roller is used as the transport roller 20. The transport rollers 20 are not limited to being made of ceramic, and may be made of metal. The transport rollers 20 are aligned at the same height so as to support the workpiece A, and are arranged in the space 10a at a predetermined pitch.

[0018] As shown in Fig. 3, the multiple transport rollers 20 are attached across the furnace body 10 by being inserted into through holes 11a, 12a facing each other in the width direction in the side walls 11, 12 of the furnace body 10. Ends of the multiple transport rollers 20 protrude from the through holes 11a, 12a to the outside of the furnace body 10, respectively. The multiple transport rollers 20 are lengthened according to the width of the furnace body 10. The multiple transport rollers 20 are supported by a drive mechanism 40 and a driven mechanism 60.

[0019] <Drive mechanism 40> The drive mechanism 40 is disposed on one side in the width direction of the furnace body 10. In this embodiment, the drive mechanism 40 faces the left side wall 11 of the furnace body 10 on the outside of the furnace body 10. As shown in Figures 2 and 3, the drive mechanism 40 includes a drive shaft 43, a power transmission mechanism 40A, and a drive unit 40B.

[0020] <Drive shaft 43> The drive shaft 43 corresponds to the plurality of conveying rollers one-to-one, and is a shaft inserted into the hollow portion of the corresponding one of the conveying rollers 20. In this embodiment, a first support plate 41 is provided so as to face the left side wall 11 of the furnace body 10. Furthermore, a second support plate 42 faces the first support plate 41 with a gap therebetween. The drive shaft 43 is attached to the pair of support plates 41, 42. The position where the drive shaft 43 is attached is set so as to face the through hole 11a provided in the furnace body 10. In the furnace body 10, as shown in FIG. 1, a plurality of conveying rollers 20 that cross the width direction are arranged along the conveying direction. In the side wall 11 of the furnace body 10, a plurality of through holes 11a are formed so as to be arranged along the conveying direction in order to insert the plurality of conveying rollers 20. As shown in FIG. 2, the plurality of drive shafts 43 are arranged in a row so as to correspond to the plurality of through holes 11a (see FIG. 1). In this embodiment, as shown in Fig. 3, each drive shaft 43 is spanned across a pair of support plates 41, 42 and rotatably attached via bearings 41a, 42a, respectively. Fig. 4 is a schematic diagram showing a support structure on the drive side of the conveying roller 20.

[0021] As shown in FIG. 4, the drive shaft 43 is a member that supports the conveying roller 20. The drive shaft 43 is supported between a pair of support plates 41, 42, and extends along the width direction of the furnace body 10. The drive shaft 43 protrudes from the support plate 41 facing the left side wall 11 of the furnace body 10, and extends toward the through hole 11a of the furnace body 10. The drive shaft 43 includes a base end shaft portion 43a, a base portion 43b, a spring seat 43c, and an insertion end 43d. In addition, a coil spring 25 is attached to the drive shaft 43.

[0022] <Base end shaft portion 43a, transmission sprocket 40b> The base end shaft portion 43a is a shaft portion that is attached to the bearings 41a, 42a attached to the pair of support plates 41, 42. The base end shaft portion 43a is a substantially cylindrical shaft, and a key groove 43a1 is provided in the middle portion of the base end shaft portion 43a. The transmission sprocket 40b of the power transmission mechanism 40A is attached to the key groove 43a1 provided in the base end shaft portion 43a. Cylindrical collars 44, 45 are respectively attached to both sides of the middle portion where the key groove 43a1 is provided, and the drive sprocket 40a is positioned. The length of the base end shaft portion 43a is longer than the distance between the support plates 41, 42. The base end shaft portion 43a is thickened at a portion 43a2 that protrudes from the support plate 41 facing the left side wall 11 of the furnace body 10.

[0023] <Coil spring 25> A base 43b is provided at a portion extending toward the furnace body 10 side beyond the portion 43a2 protruding from the support plate 41. A spring seat 43c is provided on the outer peripheral surface of the base 43b. An insertion end 43d is provided at the base 43b, which extends toward the furnace body 10 side along the axial direction. As shown in FIG. 4, a coil spring 25 is attached to the base 43b. The coil spring 25 is sandwiched between the spring seat 43c and the end 20a of the conveying roller 20 attached to the insertion end 43d. The coil spring 25 supports the end of the conveying roller 20 by an appropriate elastic reaction force along the axial direction of the conveying roller 20.

[0024] <Insertion end 43d> The insertion end 43d is provided at the tip of the drive shaft 43 extending toward the furnace body 10, and is a portion inserted into the hollow portion of the conveying roller 20. The insertion end 43d is pointed in a cone shape toward the center of rotation. In this embodiment, the insertion ends 43d of the drive shafts 43 inserted into the hollow portion of the conveying roller 20 are each pointed in a cone shape toward the center of rotation. Here, among the multiple drive shafts 43, in the drive shaft 43 on which some of the multiple conveying rollers 20 that are not frequently replaced are mounted, the insertion end 43d of the drive shaft 43 does not have to be pointed in a cone shape toward the center of rotation. In addition, all of the insertion ends 43d of the multiple drive shafts 43 may be pointed in a cone shape. In addition, in this embodiment, the insertion ends 43d of the multiple drive shafts 43 are each pointed toward the center of rotation of the drive shaft 43.

[0025] Specifically, in this embodiment, the insertion end 43d further includes a tapered portion 43d2 that expands in diameter from an end 43d1 that is pointed like a cone toward the center of rotation toward the base end side. Furthermore, in this embodiment, the insertion end 43d includes a roller support end 43d3 and a small diameter shaft portion 43d4. The roller support end 43d3 is provided on the base end side of the tapered portion 43d2, has an outer diameter according to the inner peripheral surface of the conveying roller 20, and is a portion that supports the inner peripheral surface of the conveying roller 20. The small diameter shaft portion 43d4 is provided on the base end side of the roller support end 43d3, and is a shaft portion with a smaller diameter than the roller support end 43d3.

[0026] <Power transmission mechanism 40A> As shown in Fig. 2, the power transmission mechanism 40A is a mechanism that rotates and drives the drive shaft 43. The power transmission mechanism 40A includes a drive sprocket 40a, a plurality of transmission sprockets 40b, a floating sprocket 40c, and an endless chain 40h. The power transmission mechanism 40A transmits the driving force of the drive unit 40B to the transmission sprocket 40b through the meshing of the endless chain 40h with the transmission sprocket 40b.

[0027] <Drive unit 40B, drive sprocket 40a> The driving device 40B may be, for example, a motor or the like. The driving sprocket 40a is a sprocket attached to the output shaft of the driving device 40B. Although not shown, the driving device 40B may have an output shaft provided via a reducer, a clutch, a coupling, or the like, and the driving sprocket 40a may be attached to the output shaft. In this embodiment, as shown in FIG. 2, the driving device 40B is fixed to a frame 40B1 arranged beside the furnace body 10. In addition, a separate frame 40B2 is attached to the side of the furnace body 10. A base 49 is further attached to the frame 40B2. Furthermore, a frame 47 for supporting a pair of support plates 41, 42 is attached to the base 49. The pair of support plates 41, 42 are hung over these frames 47 attached to the side of the furnace body 10.

[0028] <Transmission sprocket 40b> As described above, the transmission sprocket 40b is a sprocket attached to the drive shaft 43. In this embodiment, the transmission sprocket 40b is fixedly attached to the base end shaft portion 43a of the drive shaft 43.

[0029] <Floating sprocket 40c> The floating sprockets 40c are sprockets that form a circular track on which the endless chain 40h runs. The floating sprockets 40c are arranged at predetermined positions so as to form a predetermined circular track together with the driving sprocket 40a and the transmission sprockets 40b attached to the driving shafts 43. In this embodiment, the floating sprockets 40c are attached to a frame 40B1 to which the driving device 40B is fixed and a pair of support plates 41, 42 to which the driving shafts 43 are supported. Among the floating sprockets 40c, the floating sprockets 40c1 arranged at both ends of the transmission sprockets 40b arranged in a row turn back the track of the endless chain 40h and are also called turn rollers. The floating sprockets 40c2 arranged on both sides of the driving sprocket 40a can be adjusted vertically relative to the frame 40B1, and the length of the circular track on which the endless chain 40h runs can be adjusted. For example, when the drive unit 40B is to be installed or removed, the endless chain 40h can be slackened and removed from the drive sprocket 40a.

[0030] <Endless chain 40h> The endless chain 40h is attached along a predetermined track and meshes with the drive sprocket 40a and the transmission sprocket 40b. In this embodiment, the endless chain 40h runs along the underside of the transmission sprockets 40b arranged in a row on the side of the furnace body 10, and a chain rail 40h1 is provided at this location. The chain rail 40h1 supports the endless chain 40h from below so as to push up the endless chain 40h, and the endless chain 40h is meshed with the transmission sprocket 40b by the chain rail 40h1. The multiple transmission sprockets 40b attached to each drive shaft 43 have the same fraction. Therefore, the transmission sprockets 40b arranged in a row rotate in mesh with the endless chain 40h, and each drive shaft 43 rotates synchronously at the same speed.

[0031] <Following mechanism 60> As shown in FIG. 3, the driven mechanism 60 is disposed on the opposite side of the drive mechanism 40 in the width direction of the furnace body 10. The driven mechanism 60 faces the right side wall 12 of the furnace body 10 on the outside of the furnace body 10. FIG. 5 is a schematic diagram showing a support structure of the driven side of the conveying roller 20. In this embodiment, as shown in FIG. 5, the driven mechanism 60 is disposed on the other side of the width direction of the furnace body and is a mechanism for driving a plurality of conveying rollers 20. The driven mechanism 60 has a structure similar to that of the drive mechanism 40 (see FIG. 4) except for the power transmission mechanism 40A. As shown in FIG. 5, the driven mechanism 60 has a driven shaft 63 instead of the drive shaft 43 (see FIG. 4) of the drive mechanism 40. The driven shaft 63 is spanned across a pair of support plates 61 and 62 and is rotatably attached via bearings 41a and 42a, respectively.

[0032] <Driven shaft 63> The driven shaft 63, like the drive shaft 43 (see FIG. 4), includes a base end shaft portion 63a, a base portion 63b, a spring seat 63c, and an insertion end 63d. In this embodiment, the insertion end 63d does not have a pointed tip like a pyramid, unlike the drive shaft 43. In this manner, the driven shaft 63 does not need to have a pointed tip like a pyramid.

[0033] In this embodiment, the insertion end 63d of the driven shaft 63 includes a roller support end 63d3 and a small diameter shaft portion 63d4. The roller support end 63d3 is provided at the tip of the insertion end 63d, has an outer diameter according to the inner peripheral surface of the conveying roller 20, and is a portion that supports the inner peripheral surface of the conveying roller 20. In this embodiment, the outer peripheral surface of the roller support end 63d3 is a convex curved surface that continues in the circumferential direction. Specifically, in this embodiment, the outer peripheral surface of the roller support end 63d3 is formed by a spherical surface having a center on the central axis line of the support shaft. In addition, the tip of the roller support end 63d3 is flat. The small diameter shaft portion 63d4 is provided on the base end side of the roller support end 63d3 and is a shaft portion with a smaller diameter than the roller support end 63d3.

[0034] In addition, a coil spring 26 is attached to the driven shaft 63. The coil spring 26 is attached to the base portion 63b, and is sandwiched between the spring seat 63c and the end portion 20b of the conveying roller 20 attached to the insertion end 63d. The coil spring 26 supports the end portion of the conveying roller 20 by an appropriate elastic reaction force along the axial direction of the conveying roller 20.

[0035] The structures of the drive mechanism 40 and the driven mechanism 60 are not limited to these. For example, the track of the endless chain 40h, the arrangement of the drive device 40B, the support structure of the drive shaft 43, and the like can be modified in various ways.

[0036] In the continuous heating furnace 1, as shown in FIG. 3, the conveying roller 20 is passed to the furnace body 10 through the through holes 11a, 12a formed in the left and right side walls 11, 12 of the furnace body 10 so that the conveying roller 20 crosses the furnace body 10. At one end of the conveying roller 20, the insertion end 43d of the drive shaft 43 with the coil spring 25 attached thereto is inserted into the hollow portion of the conveying roller 20. At the other end of the conveying roller 20, the insertion end 63d of the driven shaft 63 with the coil spring 25 attached thereto is inserted into the hollow portion of the conveying roller 20. As a result, the inner circumferential surfaces of both ends of the conveying roller 20 are supported by the insertion end 43d of the drive shaft 43 and the insertion end 63d of the driven shaft 63, and the conveying roller 20 is pressed in the axial direction by the elastic reaction force of the coil spring 25. With this support structure, the conveying roller 20 rotates stably while absorbing distortion.

[0037] In such a continuous heating furnace 1, the conveying roller 20 may be damaged or distorted due to continuous use. For this reason, there are cases where it is desired to replace the damaged or distorted conveying roller 20. To replace the conveying roller 20, it is necessary to remove the conveying roller 20 from either the driving mechanism 40 side or the driven mechanism 60 side, and insert a new conveying roller 20.

[0038] As shown in Fig. 4, the drive mechanism 40 has a transmission sprocket 40b attached to a drive shaft 43, and an endless chain 40h engages with it. For this reason, when replacing the conveyor roller 20, it is troublesome to remove and insert the conveyor roller 20 from the drive mechanism 40 side. In contrast, the driven mechanism 60 side does not have a power transmission mechanism 40A such as the transmission sprocket 40b and the endless chain 40h, and is therefore suitable for removing and inserting the conveyor roller 20.

[0039] When inserting the conveying roller 20 from the driven mechanism 60 side, the conveying roller 20 is inserted through the through hole 12a formed in the side wall 12 of the furnace body 10. The conveying roller 20 is inserted into the through hole 11a on the driving side across the furnace body 10. In this embodiment, the insertion end 43d of the drive shaft 43 is pointed in a cone shape.

[0040] Fig. 6 is a side view of the insertion end 43d of the drive shaft 43. Fig. 6 illustrates a state in which the conveying roller 20 is attached to the insertion end 43d of the drive shaft 43 by being pushed in from the driven mechanism 60 side.

[0041] 6, when the conveying roller 20 is inserted into the through-hole 11a on the drive side, the tip of the insertion end 43d of the drive shaft 43 fits into the hollow portion of the conveying roller 20. When the conveying roller 20 is further pushed in, the center of the tip of the conveying roller 20 is aligned with the outer circumferential surface of the insertion end 43d of the drive shaft 43, which is pointed like a spindle, and the tip of the conveying roller 20 is attached to the insertion end 43d of the drive shaft 43.

[0042] In this way, the conveying roller 20 is attached to the drive shaft 43 by pushing it in from the driven mechanism 60 side. This allows the conveying roller 20 to be attached to the furnace body 10 with a small number of people, and makes the work of attaching the conveying roller 20 to the furnace body 10 easier. Note that the through hole 11a may have a function of guiding the hollow part of the end of the conveying roller 20 so that the hollow part of the end of the conveying roller 20 being pushed in can enter the insertion end 43d of the drive shaft 43 that is pointed like a spindle.

[0043] From this viewpoint, it is preferable that the insertion ends 43d of all of the drive shafts 43 in the continuous heating furnace 1 are sharpened in a cone shape. This makes it possible to attach the conveying roller 20 to the drive shaft 43 by pushing the conveying roller 20 from the driven mechanism 60 side in all of the drive shafts 43 in the continuous heating furnace 1. Note that the continuous heating furnace 1 may include some of the drive shafts 43 whose insertion ends 43d are not sharp. For example, if the conveying rollers 20 that are replaced frequently among the conveying rollers 20 in the continuous heating furnace 1 are determined in advance, a drive shaft 43 whose insertion end 43d is sharpened in a cone shape may be used at the location where the conveying roller 20 is attached.

[0044] The insertion ends 43d of the drive shafts 43 are preferably pointed toward the center of rotation of the drive shafts 43. In other words, the center of the cone-shaped pointed portion is aligned with the central axis of the drive shafts 43. This stabilizes the center of the insertion ends 43d of the drive shafts 43 in the through holes 11a. Therefore, by pushing the conveying rollers 20 from the driven mechanism 60 side, the conveying rollers 20 can be easily attached to the drive shafts 43.

[0045] In this embodiment, the insertion end 43d of the drive shaft 43 further includes a tapered portion that expands in diameter from the cone-shaped pointed end toward the base end, as shown in Fig. 6. Here, in this embodiment, the tapered portion 43d2 is a portion that functions as a guide for guiding the conveying roller 20 to the center when the conveying roller 20 is attached to the insertion end 43d.

[0046] From this viewpoint, the tapered portion 43d2 may have an appropriate gradient α with respect to the rotation center line CL of the drive shaft 43. The gradient of the tapered portion 43d2 may be, for example, about 20 to 60°, for example, about 30 to 45°. The longer the length L1 from the roller support end 43d3 to the tip of the insertion end 43d, the easier it is for the tip of the insertion end 43d, which is pointed like a cone, to enter the hollow portion at the end of the conveying roller 20. Here, the length L1 is, in other words, the length from the position of the thickest diameter on the tip side of the roller support end 43d3 that supports the conveying roller 20 to the tip of the insertion end 43d. However, the tip of the insertion end 43d does not need to be sharper than necessary. From this viewpoint, the length L1 from the roller support end 43d3 to the tip of the insertion end 43d may be, for example, about 0.6 to 1.5 times the outermost diameter (radius r1) of the roller support end 43d3.

[0047] The tip of the end 43d1 pointed in a cone shape may be rounded or flat. If the tip of the end 43d1 pointed in a cone shape is rounded or flat, the conveying roller 20 is less likely to be damaged even if it hits the conveying roller 20. The pointed tip of the insertion end 43d is preferably pointed toward the rotation center of the insertion end 43d. In this case, the pointed tip of the insertion end 43d is preferably positioned approximately at the center of the through hole 11a of the side wall 11 of the furnace body 10. In this case, the pointed tip of the insertion end 43d is preferably fitted into the hollow portion of the end of the conveying roller 20 inserted into the through hole 11a.

[0048] Here, the conveying roller 20 does not necessarily enter straight with respect to the rotation center line CL of the drive shaft 43. For example, the refractory material such as firebricks constituting the furnace wall of the furnace body 10 may be deformed. In such a case, it is necessary to shift the position of the drive shaft 43 supporting the conveying roller 20 so that the conveying roller 20 does not interfere with the through hole 11a formed in the furnace wall. In this way, even if the position of the drive shaft 43 supporting the conveying roller 20 is shifted, it is desirable to suppress the deterioration of the conveying performance of the conveying roller 20 and the stress concentration acting on the conveying roller 20 supported by the drive shaft 43 so as to be small.

[0049] The insertion end 43d of the drive shaft is provided with a roller support end 43d3 on the base end side of the tapered portion 43d2. The roller support end 43d3 has an outer diameter corresponding to the inner peripheral surface of the conveying roller 20 and is a portion that supports the inner peripheral surface of the conveying roller 20.

[0050] By providing the roller support end 43d3 on the base end side of the tapered portion 43d2, the conveying roller 20 guided along the tapered portion 43d2 can be smoothly supported. The roller support end 43d3 may be a curved surface with a constant curvature. In addition, an annular support surface may be provided on the roller support end 43d3 that receives the inner peripheral surface of the end of the conveying roller 20 when the drive shaft 43 and the conveying roller 20 are concentric. The width w1 of the annular support surface in the central axis direction may be, for example, 5 mm or less. Note that the annular support surface may not be provided as long as the conveying roller 20 guided along the tapered portion 43d2 can be smoothly supported.

[0051] In this embodiment, the roller support end 43d3 is further provided at its base end with a small diameter shaft portion 43d4 having a smaller diameter than the roller support end 43d3. On the premise that the drive shaft 43 has a required rigidity, the outer diameter (radius) of the small diameter shaft portion 43d4 is preferably about 1 to 5 mm smaller than the outermost diameter (radius: r1) of the roller support end 43d3. In this case, for example, the diameter difference between the roller support end 43d3 and the inner peripheral surface of the cylindrical end of the conveying roller 20 is preferably 0.75 mm or less. When such a clearance exists between the roller support end 43d3 and the conveying roller 20, the conveying roller 20 may be inclined with respect to the rotation center line CL of the drive shaft 43. The roller support end 43d3 is preferably formed in a shape in which the crossing angle of the conveying roller 20 with respect to the rotation center line CL of the drive shaft 43 is allowed within an angle range of 7 degrees. The conveying roller 20 fits easily into the insertion end 43d of the drive shaft 43, and meandering of the conveyed object is suppressed. The diameter difference between the roller support end 43d3 and the inner circumferential surface of the cylindrical end of the conveying roller 20 is not limited to the above. The diameter difference between the roller support end 43d3 and the inner circumferential surface of the cylindrical end of the conveying roller 20 can be changed as appropriate, and may be 0.75 mm or more.

[0052] The part of the roller support end 43d3 that supports the inner circumferential surface of the conveying roller 20 may be a convex curved surface that continues in the circumferential direction, as shown in FIG. 6. In this case, in the form shown in FIG. 6, the convex curved surface of the roller support end 43d3 is formed by a spherical surface having a center on the rotation center line CL of the drive shaft 43. In this case, even if the position of the drive shaft 43 that supports the conveying roller 20 is shifted so that the conveying roller 20 does not interfere with the through hole 11a, stress concentration can be suppressed without deteriorating the conveying performance. In addition, even if the position of the drive shaft 43 is shifted, there is no change in the clearance between the inner circumferential surface of the end of the conveying roller 20 and the roller support end 43d3 of the drive shaft 43 fitted into the conveying roller 20. Therefore, the conveying performance of the conveying roller 20 is preferably maintained.

[0053] From the same viewpoint, the convex curved surface of the roller support end 43d3 may be formed by a curved surface having a radius of curvature shorter than the maximum diameter of the roller support end 43d3 in a cross section passing through the central axis of the roller support end 43d3. The part of the roller support end 43d3 that supports the inner peripheral surface of the conveying roller 20 may have a cylindrical surface parallel to the rotation center line CL of the roller support end 43d3. In this case, the width of the cylindrical surface forming the annular support surface is preferably 5 mm or less. According to the knowledge of the present inventors, if the width of the cylindrical surface is 5 mm or less, even if the position of the drive shaft 43 is shifted, the conveying performance of the conveying roller 20 is not deteriorated and stress concentration occurring in the conveying roller 20 can be suppressed.

[0054] In this embodiment, the drive mechanism 40 includes a plurality of drive shafts 43 and a power transmission mechanism 40A. As shown in FIG. 2, the power transmission mechanism 40A includes a drive unit 40B, a drive sprocket 40a attached to the drive unit 40B, a plurality of transmission sprockets 40b attached to the plurality of drive shafts 43, and an endless chain 40h meshed with the drive sprocket 40a and the plurality of transmission sprockets 40b. In this manner, the transmission sprocket 40b of the drive shaft 43 meshes with the endless chain 40h. For this reason, it is more difficult to replace the conveying roller 20 from the drive mechanism 40 side than from the driven mechanism 60 side (see FIG. 3). Since the conveying roller 20 can be replaced from the driven mechanism 60 side in this continuous heating furnace 1, the maintainability is improved.

[0055] In this embodiment, the drive shaft 43 is mentioned, but a similar support shaft may be used on the driven mechanism 60 side. That is, the insertion ends 63d of the multiple driven shafts 63 to be inserted into the hollow parts of the conveying rollers 20 may each be sharpened like a cone. In this case, the insertion ends 63d of the driven shafts 63 are also sharpened like a cone on the driven mechanism 60 side, so that it is easy to insert the insertion ends 63d of the driven shafts 63 into the hollow parts of the conveying rollers 20. This makes it easier to install the conveying rollers 20 on the driven mechanism 60 side, improving maintainability.

[0056] Although the detailed description has been given above with reference to specific embodiments, these are merely examples and do not limit the scope of the claims. Thus, the technology described in the claims includes various modifications and changes to the embodiments described above. In addition, the continuous heating furnace proposed here can be modified in various ways, and each component and each process mentioned here can be omitted or combined as appropriate, as long as no particular problem occurs.

[0057] This specification includes the following items 1 to 12.

[0058] Section 1: A tunnel-shaped furnace body that encloses a space along the conveying direction; A plurality of conveying rollers arranged along the conveying direction and crossing the tunnel-shaped furnace body, A drive mechanism is disposed on one side of the furnace body in the width direction and drives the plurality of conveying rollers; a driven mechanism disposed on the other side of the furnace body in the width direction and supporting the plurality of conveying rollers; Equipped with Each of the plurality of conveying rollers is a hollow shaft member, The drive mechanism includes: a plurality of drive shafts each corresponding to the plurality of conveying rollers and each being inserted into a hollow portion of a corresponding one of the conveying rollers; a power transmission mechanism to which the plurality of drive shafts are connected; A drive device connected to the power transmission mechanism; Equipped with The driven mechanism includes: A plurality of driven shafts are disposed on the other side of the furnace body in the width direction and are inserted into corresponding hollow portions of the plurality of conveying rollers, At least some of the drive shafts have insertion ends that are inserted into the hollow portions of the conveying rollers and are each pointed in a cone shape.

[0059] Section 2: Item 2. The continuous heating furnace according to item 1, wherein the insertion ends of the plurality of drive shafts are all pointed in a cone shape.

[0060] Section 3: Item 2. The continuous heating furnace according to item 1, wherein the insertion ends of the plurality of drive shafts are each pointed toward the center of rotation of the drive shaft.

[0061] Section 4: The insertion end of the drive shaft is Item 4. The continuous heating furnace according to item 3, further comprising a tapered portion whose diameter increases from the cone-shaped pointed end toward the base end.

[0062] Section 5: The insertion end of the drive shaft is Item 2. The continuous heating furnace according to item 1, further comprising a roller support end portion provided on the base end side of the tapered portion, having an outer diameter corresponding to the inner peripheral surface of the conveying roller, and supporting the inner peripheral surface of the conveying roller.

[0063] Item 6: The insertion end of the drive shaft is a small diameter shaft portion having a smaller diameter than the roller support end portion, the small diameter shaft portion being provided on a base end side of the roller support end portion; Item 6. The continuous heating furnace according to item 5, further comprising:

[0064] Section 7: Item 2. The continuous heating furnace according to item 1, wherein a portion of the roller support end portion that supports the inner peripheral surface of the conveying roller is a convex curved surface that is continuous in the circumferential direction.

[0065] Section 8: Item 6. The continuous heating furnace according to item 5, wherein the convex curved surface is formed by a spherical surface having a center on the central axis line of the drive shaft.

[0066] Section 9: Item 6. The continuous heating furnace according to item 5, wherein the convex curved surface is formed by a curved surface having a radius of curvature shorter than a maximum diameter of the roller support end in a cross section passing through a central axis of the roller support end.

[0067] Section 10: Item 2. The continuous heating furnace according to item 1, wherein a portion of the roller support end portion that supports the inner peripheral surface of the conveying roller has a cylindrical surface parallel to a central axis of the roller support end portion.

[0068] Section 11: The power transmission mechanism includes: A drive unit; a drive sprocket attached to the drive; a plurality of transmission sprockets respectively attached to the plurality of drive shafts; an endless chain engaged with the drive sprocket and the plurality of transmission sprockets; The continuous heating furnace according to item 1,

[0069] Section 12: Item 2. The continuous heating furnace according to item 1, wherein the ends of the driven shafts that are inserted into the hollow portions of the conveying rollers are each pointed in a cone shape. [Explanation of symbols]

[0070] 1 Continuous heating furnace 10 Furnace body 10a space 10b Frame 11,12 side wall 11a,12a through hole 13 Bottom wall 14 Ceiling Wall 16 Exterior Wall 20 Conveyor roller 20a,20b end 30 Heater 40 Drive mechanism 40A Power transmission mechanism 40B Drive unit 40B1 Frame 40B2 Frame 40a drive sprocket 40b transmission sprocket 40c, 40c1, 40c2 floating sprocket 40h endless chain 40h1 chain rail 41,42 Support plate 41a, 42a Bearings 43 Drive shaft 43a Proximal shaft part 43a1 Key groove 43a2 Part protruding from the support plate 41 43b base 43c Spring seat 43d Insertion end 43d1 End of insertion end 43d 43d2 Tapered section 43d3 Roller support end 43d4 Small diameter shaft part 44,45 Color 47 Frames 49 Base 60 Driven mechanism 61,62 Support plate 63 Driven shaft 63a Proximal shaft part 63b base 63c Spring seat 63d Insertion end 63d3 Roller support end 63d4 Small diameter shaft A. Processing object CL Rotational centerline of drive shaft 43 r1: outermost diameter (radius) of the roller support end 43d3 w1: the width of the annular support surface of the roller support end 43d3 in the central axis direction α Gradient of the tapered portion 43d2

Claims

1. A tunnel-shaped furnace body that encloses a space along the conveying direction; A plurality of conveying rollers arranged along the conveying direction and crossing the tunnel-shaped furnace body, A drive mechanism is disposed on one side of the furnace body in the width direction and drives the plurality of conveying rollers; a driven mechanism disposed on the other side of the furnace body in the width direction and supporting the plurality of conveying rollers; Equipped with Each of the plurality of conveying rollers is a hollow shaft member, The drive mechanism includes: a plurality of drive shafts each corresponding to the plurality of conveying rollers and each being inserted into a hollow portion of a corresponding one of the conveying rollers; a power transmission mechanism to which the plurality of drive shafts are connected; A drive device connected to the power transmission mechanism; Equipped with The driven mechanism includes: A plurality of driven shafts are disposed on the other side of the furnace body in the width direction and are inserted into corresponding hollow portions of the plurality of conveying rollers, At least some of the drive shafts have insertion ends that are inserted into the hollow portions of the conveying rollers and are each pointed in a cone shape.

2. 2. The continuous heating furnace according to claim 1, wherein all of the insertion ends of the plurality of drive shafts are pointed in a cone shape.

3. 2. The continuous heating furnace according to claim 1, wherein the insertion ends of the plurality of drive shafts are each pointed toward a center of rotation of the drive shaft.

4. The insertion end of the drive shaft is 4. The continuous heating furnace according to claim 3, further comprising a tapered portion whose diameter increases from the cone-shaped pointed end toward a base end.

5. The insertion end of the drive shaft is 2. The continuous heating furnace according to claim 1, further comprising a roller support end portion provided on a base end side of the tapered portion, having an outer diameter corresponding to the inner peripheral surface of the conveying roller, and supporting the inner peripheral surface of the conveying roller.

6. The insertion end of the drive shaft is a small diameter shaft portion having a smaller diameter than the roller support end portion, the small diameter shaft portion being provided on a base end side of the roller support end portion; 6. The continuous heating furnace of claim 5, further comprising:

7. 2. The continuous heating furnace according to claim 1, wherein a portion of the roller support end portion that supports the inner peripheral surface of the transport roller has a convex curved surface that is continuous in the circumferential direction.

8. 6. The continuous heating furnace according to claim 5, wherein the convex curved surface is formed by a spherical surface having a center on the central axis of the drive shaft.

9. 6. The continuous heating furnace according to claim 5, wherein the convex curved surface is formed by a curved surface having a radius of curvature shorter than a maximum diameter of the roller support end in a cross section passing through a central axis of the roller support end.

10. 2. The continuous heating furnace according to claim 1, wherein a portion of said roller support end portion that supports the inner peripheral surface of said transport roller has a cylindrical surface that is parallel to a central axis of said roller support end portion.

11. The power transmission mechanism includes: A drive unit; a drive sprocket attached to the drive; a plurality of transmission sprockets respectively attached to the plurality of drive shafts; an endless chain engaged with the drive sprocket and the plurality of transmission sprockets; 2. The continuous heating furnace according to claim 1, comprising:

12. 2. The continuous heating furnace according to claim 1, wherein each of the plurality of driven shafts has an insertion end, which is inserted into the hollow portion of the conveying roller, pointed in a cone shape.

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