JP6416967B2 - Conveying device in continuous heat treatment furnace - Google Patents

Description

  The present invention relates to a transfer apparatus in a continuous heat treatment furnace.

  Patent Document 1 below discloses a continuous heat treatment furnace that conveys an object to be processed into a furnace heated by a heating device and performs heat treatment on the object to be processed in the furnace. Further, as a transfer device for transferring an object to be processed, a chain transfer mechanism using a ceramic chain that generates less dust and can sufficiently withstand a high temperature environment in a heat treatment furnace is applied.

Japanese Patent Laid-Open No. 9-298163

  The ceramic chain as described above is lighter than a metal chain, but has a low strength. Therefore, it is difficult to increase the load weight of the workpiece. Although it is conceivable to increase the size of the chain components in order to increase the strength of the chain, the weight of the chain itself increases, so the load weight of the workpiece cannot be increased so much, and the heat capacity also increases. Therefore, there is a possibility of adversely affecting the thermal efficiency in the heat treatment furnace.

  The present invention has been made in view of the above circumstances, and provides a transfer device in a continuous heat treatment furnace that can suitably increase the load weight of an object to be processed without increasing the strength of the transfer chain. With the goal.

The present invention relates to a sprocket-like main drive wheel, main drive means having a main drive unit for rotationally driving the main drive wheel, a driven wheel, and an endless transport chain wound around the main drive wheel and the driven wheel. The transfer chain includes a transfer unit that transfers an object to be processed in a continuous heat treatment furnace by being pulled by the main drive wheel at one side portion between the main drive wheel and the driven wheel. The other side portion is a transfer device in a continuous heat treatment furnace that is a return portion that is forwarded from the main drive wheel side to the driven wheel side,
Auxiliary driving means for applying a driving force for rotating the main driving wheel side to the driven wheel side to the return portion ,
The auxiliary drive means includes a sprocket-like auxiliary drive wheel around which the return portion of the transport chain is wound, and an auxiliary drive unit that rotationally drives the auxiliary drive wheel,
The auxiliary drive wheel has a smaller diameter than the main drive wheel .

The maximum tension generated in the transport chain is generated at the winding start portion of the main drive wheel, that is, at the end position of the transport unit, and the size is determined by the weight of the workpiece loaded on the transport unit and the main drive means. Is roughly proportional to the weight of the transport chain routed by Therefore, in order to increase the loading weight without increasing the strength of the transport chain, it is effective to reduce the weight of the transport chain that is forwarded by the main drive means.
In the conventional transport device, the entire transport chain is rotated by a single main drive means. Therefore, the maximum tension generated at the winding start portion of the main drive wheel is the weight of the workpiece and the entire transport chain. Therefore, it is difficult to increase the load weight of the object to be processed.
On the other hand, in the present invention, there is provided auxiliary drive means for applying a driving force to the return portion of the transport chain, in addition to the main drive means, so that the transport of the transport chain is shared between the main drive means and the auxiliary drive means. can do. Therefore, the weight of the transport chain forwarded by the main drive means can be reduced, and the maximum tension generated at the end position of the transport section can be reduced, and the load weight of the workpiece can be increased correspondingly. .

It said auxiliary driving means comprises a sprocket shaped auxiliary driving wheels return portion is wound of the conveyor chain, and an auxiliary driving unit for rotating the auxiliary drive wheels, front Symbol auxiliary drive wheels, the main drive wheel small-diameter der than Ru.
Since the main drive means is responsible for the weight of the object to be processed and the weight of a part of the transport chain, increasing the diameter of the main drive wheel increases the number of teeth that mesh with the transport chain, thereby increasing the load on each tooth. It can be dispersed and made smaller. On the other hand, since the auxiliary drive wheel only takes care of the weight of the other part of the transport chain, the diameter can be reduced, thereby suppressing an increase in the size of the transport device.

The auxiliary driving means is preferably provided closer to the driven wheel than an intermediate position between the main driving wheel and the driven wheel.
With such a configuration, it is possible to increase the weight of the transport chain that the auxiliary drive means handles as much as possible, and to reduce the weight of the transport chain that the main drive means handles. Therefore, the load weight of the workpiece can be further increased.

A first slack portion in which the return portion is partially slackened is provided between the auxiliary drive means and the main drive wheel, and the return portion is partially disposed between the auxiliary drive means and the driven wheel. It is preferable that a second slack portion that is loosened is provided .
With such a configuration, it is possible to prevent the transport chain from being pulled due to a difference in the transport speed between the main drive means and the auxiliary drive means when the transport chain is simultaneously fed. .
If the second slack portion is provided between the auxiliary drive means and the driven wheel, even if the transport chain is routed only by the main drive means, the entire transport chain is routed as long as the second slack portion exists. In other words, the maximum tension generated in the transport chain also has a magnitude corresponding to the load weight of the workpiece and the weight of a part of the transport chain.

Before SL auxiliary driving means, thereby intermittently forwarding the previous SL conveyor chain when said main drive means is continuously forwarded to the conveyor chain is preferred.
Further, it is preferable that the auxiliary driving means is rotated at a higher speed than the main driving means so that the second slack portion is maintained.

When the transport chain is forwarded only by the main drive means, the amount of slack in the second slack portion gradually decreases, and when the second slack portion disappears completely, the tension generated in the transport chain increases. Therefore, before the second slack portion disappears completely, the auxiliary drive means is operated and the transport chain is forwarded at a speed higher than that of the main drive means, thereby increasing the slack amount in the second slack portion again, It becomes possible to maintain 2 slack parts. Further, by operating the auxiliary driving means intermittently, it is possible to reduce the operating cost, noise, etc., compared to the case where the auxiliary driving means is always operated.

The transport device further includes a slack measuring unit that measures a slack amount in the second slack portion,
It is preferable that the auxiliary driving unit operates when the amount of slack measured by the slack measuring unit reaches a predetermined minimum, and stops when the amount reaches a predetermined maximum.
According to this configuration, by operating and stopping the auxiliary drive unit according to the measurement result of the slack measurement unit, it is possible to prevent the second slack unit from disappearing while intermittently operating the auxiliary drive unit. .

The slack measurement unit preferably includes a detector that directly detects the minimum and maximum slack amounts of the second slack portion.
In this way, by detecting the minimum and maximum of the slack amount of the second slack portion directly by the detector, it is possible to accurately determine the timing of operation and stop of the auxiliary drive means.

The transport apparatus further includes a load detection unit that detects a load on the main drive unit,
The auxiliary drive means may operate when the load detected by the load detection unit reaches a predetermined maximum.
According to this configuration, when the load on the main drive means reaches a predetermined maximum, for example, when the load weight of the object to be processed on the transport chain increases, the maximum tension generated in the transport chain does not become excessive. The auxiliary drive means can be actuated to reduce the maximum tension. Therefore, it is possible to increase the maximum load capacity of the object to be processed.

The transport chain is preferably made of ceramic.
When the transport chain is made of ceramic, it is difficult to increase the load weight of the object to be processed, but the load weight can be effectively increased by applying each configuration of the present invention as described above. .

  According to the present invention, it is possible to increase the load weight of an object to be processed without increasing the strength of the transport chain.

It is side explanatory drawing which shows the continuous heat processing furnace which concerns on one Embodiment of this invention. It is a side view which expands and shows the main drive means in the conveying apparatus of the continuous heat processing furnace shown by FIG. It is a side view which expands and shows the auxiliary drive means in the conveyance apparatus of the continuous heat processing furnace shown by FIG. It is a graph which shows roughly the tension which arises in the conveyance chain of a conveyance device.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory side view showing a continuous heat treatment furnace according to an embodiment of the present invention.
The continuous heat treatment furnace 10 of the present embodiment heats the workpiece W in the heating chamber 12 while conveying the workpiece W by the transport device 11, and then cools the workpiece W in the cooling chamber 13. It is configured. A supply device (not shown) for supplying the workpiece W is provided on the conveyance start end position P1 side of the conveyance device 11, and a discharge device (not shown) for discharging the workpiece W is provided at the conveyance end position P2. It is done. In FIG. 1, the conveyance direction of the workpiece W is indicated by an arrow X.

  The transport device 11 includes a transport chain 21 formed in an endless shape, and a forwarding mechanism 20 that forwards the transport chain 21. The transport chain 21 is configured by connecting a number of links so as to be bendable by pins. Further, the transport chain 21 is provided in a plurality of rows (for example, two rows) in the width direction. The conveyance chain 21 of the present embodiment is made of ceramic and has high heat resistance and low dust generation.

The forwarding mechanism 20 includes a plurality of ring bodies 22 to 25, 32, 42 around which the transport chain 21 is wound, and two drive units 31, 41 that forward-drive the transport chain 21.
In this embodiment, the main drive means 31 and the auxiliary drive means 41 are provided as a drive means. Each drive means 31 and 41 is provided with a drive wheel (a main drive wheel 32 and an auxiliary drive wheel 42). Further, the forwarding mechanism 20 includes a driven wheel 22 and guide wheels 23, 24, and 25. The transport chain 21 is wound around the drive wheels 32 and 42, the driven wheel 22, and the guide wheels 23, 24 and 25. The drive wheels 32 and 42 are formed in a sprocket shape and have a plurality of teeth that mesh with the transport chain 21. The guide wheels 23, 24, 25 and the driven wheel 22 may be formed in a sprocket shape, or may be formed in a roller shape (pulley shape).

FIG. 2 is an enlarged side view showing the main drive means 31.
As shown in FIGS. 1 and 2, the main drive unit 31 includes a main drive wheel 32 and a main drive motor (main drive unit) 33 that rotationally drives the main drive wheel 32. The main drive wheel 32 and the main drive motor 33 are coupled so as to be able to transmit power by a winding transmission mechanism 34 using a chain or a belt. The main drive wheel 32 is disposed at the conveyance end position P <b> 2 in the conveyance device 11. Further, the driven wheel 22 is disposed at the conveyance start end position P <b> 1 in the conveyance device 11. The upper side of the transport chain 21 between the main drive wheel 32 and the driven wheel 22 constitutes a transport unit 26 that transports the workpiece W from the transport start position P1 to the transport end position P2. . The main drive wheel 32 is configured to transport the workpiece W by pulling the transport chain 21 at the transport end position P2.

Further, the lower side of the transport chain 21 between the main drive wheel 32 and the driven wheel 22 constitutes a return portion 27 that is sent from the main drive wheel 32 side to the driven wheel 22 side. A plurality of guide wheels 23, 24, 25 are arranged in the return portion 27.
In addition, the conveyance part 26 of the conveyance chain 21 is supported from the lower side by the upper guide member 10a1 provided in the apparatus frame 10a of the continuous heat treatment furnace 10, and the space between the guide wheels 24 and 25 in the return part 27 is also between the apparatus frames. It is supported from below by a lower guide member 10a2 provided in 10a.

  A first guide wheel 23 is disposed in the vicinity of the main drive wheel 32 upstream of the main drive wheel 32 in the transport direction X (on the right side in FIG. 2), and further in the transport direction from the first guide wheel 23. A second guide wheel 24 is arranged on the upstream side of X. The return portion 27 of the transport chain 21 is partially slackened between the first guide wheel 23 and the second guide wheel 24. In the present embodiment, the slack portion of the return portion 27 between the first guide wheel 23 and the second guide wheel 24 is referred to as a first slack portion 28.

FIG. 3 is an enlarged side view showing the auxiliary driving means 41.
As shown in FIG. 3, the auxiliary drive means 41 includes an auxiliary drive wheel 42 that is wound around the return portion 27 of the transport chain 21, and an auxiliary drive motor (auxiliary drive unit) 43 that rotationally drives the auxiliary drive wheel 42. It has. The auxiliary drive motor 43 and the auxiliary drive wheel 42 are coupled so as to be able to transmit power by a winding transmission mechanism 44 using a chain or a belt. The auxiliary drive wheel 42 is disposed near the driven wheel 22 on the downstream side in the transport direction X from the driven wheel 22. The return portion 27 of the transport chain 21 between the auxiliary drive wheel 42 and the driven wheel 22 is partially loosened. In the present embodiment, the slack portion of the return portion 27 between the auxiliary drive wheel 42 and the driven wheel 22 is referred to as a second slack portion 29.

A third guide wheel 25 is disposed in the vicinity of the auxiliary drive wheel 42 on the downstream side in the transport direction X with respect to the auxiliary drive wheel 42, and the transport chain 21 is interposed between the auxiliary drive wheel 42 and the third guide wheel 25. Arranged in a sandwiched state.
The transport device 11 includes a slack measurement unit 51 that measures the amount of slack in the second slack unit 29. Specifically, the slack measurement unit 51 includes a minimum slack detector 52 that detects that the amount of slack in the second slack unit 29 has reached a preset minimum (minimum limit amount) L1, and a preset maximum. And a maximum slack detector 53 that detects that the limit (maximum limit amount) L2 has been reached. The minimum sag detector 52 and the maximum sag detector 53 are, for example, reflective or transmissive optical sensors, and whether or not the lower end of the second sag portion 29 shields the light emitted from the detectors 52 and 53. Thus, it is configured to detect whether or not the slack amount of the second slack portion 29 has reached the minimum L1 or the maximum L2.

  In the transport apparatus 11 having the above configuration, the main drive means 31 is always operated to transport the workpiece W during operation of the continuous heat treatment furnace 10 and continuously transports the transport chain 21. On the other hand, the auxiliary drive means 41 operates intermittently according to the measurement result by the slack measurement unit 51 and applies a driving force for forwarding to the return unit 27 of the transport chain 21.

  When the main drive unit 31 operates while the auxiliary drive unit 41 is stopped, the transport unit 26 of the transport chain 21 is pulled by the main drive wheel 32 toward the transport end position P2 from the transport start end position P1. Further, the second slack portion 29 of the transport chain 21 is sequentially drawn into the transport portion 26. Therefore, the amount of slack of the second slack portion 29 gradually decreases. Further, the amount of slack in the first slack portion 28 gradually increases as the amount of slack in the second slack portion 29 decreases.

  When the amount of slack in the second slack portion 29 reaches the minimum L1, the minimum slack detector 52 detects this state, and the auxiliary drive motor 43 in the auxiliary drive means 41 operates. As a result, the return portion 27 of the transport chain 21 is forwarded by the auxiliary drive wheel 42. The forwarding speed of the transport chain 21 by the auxiliary drive means 41 is set higher than the forwarding speed of the transport chain 21 by the main drive means 31. For example, the forwarding speed by the auxiliary drive means 41 is about 1.5 times the forwarding speed by the main drive means 31. Therefore, when the auxiliary driving means 41 is operated, the amount of slack of the second slack portion 29 gradually increases. When the amount of slack of the second slack portion 29 reaches L2 as much as possible, the maximum slack detector 53 detects this state, and the auxiliary drive motor 43 stops. Thereby, the forwarding of the transport chain 21 by the auxiliary drive wheel 42 is stopped. By repeatedly performing the above operation, the auxiliary driving means 41 is intermittently operated so that the second slack portion 29 is always maintained.

  The main drive means 31 pulls the conveyance portion 26 and the second slack portion 29 of the return portion 27 in the conveyance chain 21 and pushes between the main drive wheel 32 and the first guide wheel 23 in the return portion 27. To the first slack portion 28. Therefore, the main drive means 31 is configured to rotate only a part of the transport chain 21 regardless of whether or not the auxiliary drive means 41 is operated.

  At this time, naturally, tension is generated in a part of the transport chain 21 pulled by the main drive unit 31. This tension is caused by the frictional force generated when the weight of the workpiece W loaded on the transport unit 26 and the weight of the transport unit 26 itself are applied to the upper guide member 10a1 and the weight of the second slack portion 29. It becomes the size according to. Therefore, this tension becomes maximum at the conveyance end position P2.

Such a change in tension is schematically illustrated in FIG. As shown by the solid line in FIG. 4, the tension generated in the transport unit 26 is maximum at the transport end position P2, and becomes proportionally smaller toward the transport start end position P1, exceeding the transport start end position P1, and the auxiliary drive wheel. At position P3 of 42, the tension is minimum.
On the other hand, the auxiliary drive means 41 pulls a portion of the return portion 27 of the transport chain 21 between the position P3 of the auxiliary drive wheel 42 and the first guide wheel 23. The tension generated in the portion has a magnitude corresponding to the frictional force generated when the weight of the portion is applied to the lower guide member 10 a 2 and the weight of the first slack portion 28. Therefore, the tension generated from the position P3 of the auxiliary drive wheel 42 to the position P2 of the main drive wheel 32 in the return portion 27 changes as shown on the right side of FIG.

Further, in FIG. 4, as a comparative example with respect to the present embodiment, the tension applied to the transport unit 26 when the auxiliary drive unit 41 and the second slack portion 29 are not provided (in the conventional case) is indicated by a two-dot chain line. Yes. When the auxiliary driving means 41 and the second slack portion 29 are not provided, the entire driving chain 21 is routed by the main driving means 31, so that the weight of the return portion 27 is added to the conveying portion 26 of the conveying chain 21. The corresponding tension is also added, and the maximum tension becomes excessive.
Therefore, in the present embodiment, it is possible to reduce the maximum tension applied to the transport chain 21 by providing the auxiliary driving means 41 and the second slack portion 29. In this way, by reducing the load generated on the transport chain 21, it is possible to increase the load weight of the workpieces W that can be transported by the transport chain 21.

  In particular, when the transport chain 21 is made of ceramic as in the present embodiment, it is difficult to increase the load weight because the strength is reduced compared to the case where the transport chain 21 is made of metal, and in order to increase the strength, When the dimensions of the constituent members are increased, the load weight cannot be increased so much due to the increase in the weight of the transport chain 21 itself, and the thermal efficiency in the continuous heat treatment furnace 10 may be adversely affected due to the increase in the heat capacity of the transport chain 21. In this respect, in this embodiment, since the load weight of the workpiece W can be increased without increasing the strength of the transport chain 21, it is very useful for the transport device 11 using the ceramic transport chain 21. It is.

In the present embodiment, since the auxiliary driving unit 41 operates intermittently, it is possible to reduce the operating cost and noise compared to the case where the auxiliary driving unit 41 operates constantly.
Since the first slack portion 28 is provided between the main drive means 31 and the auxiliary drive means 41, when both the main drive means 31 and the auxiliary drive means 41 are operating, their forward speeds The conveyance chain 21 can be prevented from being pulled by the difference.

In the present embodiment, the minimum slack detector 52 and the maximum slack detector 53 detect the minimum L1 and the maximum L2 of the slack amount of the second slack portion 29, and the auxiliary drive means 41 is based on the detection result. Since it operates, the amount of slack of the second slack portion 29 can be accurately controlled, and the second slack portion 29 can be reliably maintained.
Further, the auxiliary drive means 41 is disposed closer to the driven wheel 22 than an intermediate position between the main drive wheel 32 and the driven wheel 22, and more specifically, is disposed in the vicinity of the conveyance start end position P1 of the workpiece W. Therefore, it is possible to increase the weight of the transport chain 21 forwarded by the auxiliary drive unit 41 and relatively reduce the weight of the transport chain 21 forwarded by the main drive unit 31. Therefore, the load weight of the workpiece W can be easily increased.

The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the invention described in the claims.
For example, the slack measurement unit 51 that measures the amount of slack in the second slack unit 29 may include only one of the minimum slack detector 52 and the maximum slack detector 53. When only the minimum slack detector 52 is provided, the auxiliary driving means 41 is activated when the minimum slack detector 52 detects that the slack amount in the second slack portion 29 has reached the minimum L1, and the slack amount is maximized. What is necessary is just to stop the auxiliary drive means 41 at the timing when the time assumed to reach the limit L2 has elapsed. When only the maximum slack detector 53 is provided, the auxiliary drive means 41 is stopped when the maximum slack detector 53 detects that the slack amount in the second slack portion 29 has reached the maximum L2, and then the slack amount. The auxiliary drive means 41 may be operated at the timing when the time assumed to reach the minimum L1 has elapsed. By providing only one detection unit, the number of parts can be reduced, and the manufacturing cost can be reduced.

Further, the slack measurement unit 51 may measure a slack amount based on the weight of the second slack unit 29. In this case, a weight sensor such as a load cell may be provided on the support portion of the driven wheel 22 or the auxiliary drive wheel 42, and the auxiliary drive means 41 may be operated according to the detection result of the weight sensor.
Further, when the second slack portion 29 and the detectors 52 and 53 are omitted, a load detection portion for detecting a load applied to the main drive motor 33 in the main drive means 31 is provided, and the load exceeds a predetermined maximum. Alternatively, the auxiliary driving means 41 may be operated. In this case, the load applied to the main drive motor 33 can be detected by measuring the current value supplied to the main drive motor 33. Further, the auxiliary drive wheels 42 in the auxiliary drive means 41 may be supported via a one-way clutch so that the auxiliary drive wheels 42 can idle following the rotation of the transport chain 21 even when stopped.

The auxiliary drive means 41 may always operate together with the main drive means 31. In this case, the auxiliary drive unit 41 and the main drive unit 31 may feed the transport chain 21 at the same speed. Further, the transport chain 21 is not limited to ceramic but may be made of metal or the like.
The transfer apparatus 11 of the present invention can be applied to any continuous heat treatment furnace such as a heat treatment furnace that performs surface treatment of the workpiece W and a heat treatment furnace that performs a drying process.

10: continuous heat treatment furnace 11: transfer device 21: transfer chain 22: driven wheel 26: transfer unit 27: return unit 28: first slack unit 29: second slack unit 31: main drive means 32: main drive wheel 33: main Drive motor (main drive unit)
41: Auxiliary drive means 42: Auxiliary drive wheel 43: Auxiliary drive motor (auxiliary drive unit)
51: Sag measuring unit 52: Minimum sag detector 53: Maximum sag detector L1: Minimum L2: Maximum W: Workpiece

Claims (9)

A main driving means having a sprocket-like main driving wheel and a main driving portion for rotationally driving the main driving wheel; a driven wheel; and an endless transport chain wound around the main driving wheel and the driven wheel; The transfer chain is a transfer unit that transfers an object to be processed in a continuous heat treatment furnace by pulling one side portion between the main drive wheel and the driven wheel by the main drive wheel. The side unit is a transfer device in a continuous heat treatment furnace that is a return unit that is forwarded from the main drive wheel side to the driven wheel side,
Auxiliary driving means for applying a driving force for rotating the main driving wheel side to the driven wheel side to the return portion ,
The auxiliary drive means includes a sprocket-like auxiliary drive wheel around which the return portion of the transport chain is wound, and an auxiliary drive unit that rotationally drives the auxiliary drive wheel,
The auxiliary drive wheel is a transfer device in a continuous heat treatment furnace having a smaller diameter than the main drive wheel . The conveying device in the continuous heat treatment furnace according to claim 1, wherein the auxiliary drive means is provided closer to the driven wheel than an intermediate position between the main drive wheel and the driven wheel. Between the auxiliary drive means and the main drive wheel, a first slack portion in which the return portion is partially slackened is provided ,
Wherein between the auxiliary drive means and said driven wheel, the second slack portion slackened the return portion partially is provided, the conveying device in a continuous heat treatment furnace according to claim 1 or 2. Before SL auxiliary driving means, when said main drive means is continuously forwarded to the conveyor chain, prior SL intermittently to route the conveyor chain, the conveying device in the continuous heat treatment furnace according to claim 3. A slack measurement unit for measuring the amount of slack in the second slack unit;
The said auxiliary drive means is a transfer apparatus in the continuous heat processing furnace of Claim 4 which operate | moves when the amount of slack measured by the said slack measurement part reaches a predetermined minimum, and stops when it reaches a predetermined maximum. The said slack measurement part is a conveyance apparatus in the continuous heat processing furnace of Claim 5 containing the detector which detects the minimum and maximum of the slack amount of a 2nd slack part. The said auxiliary drive means is a conveyance apparatus in the continuous heat processing furnace of Claim 4 which makes the said conveyance chain forward at a higher speed than the said main drive means so that the said 2nd slack part may be maintained.
A load detector for detecting a load on the main drive means;
It said auxiliary driving means is actuated when the load detected by the load detector has reached a predetermined maximum transport apparatus in a continuous heat treatment furnace according to any one of claims 1-7. The conveying apparatus in the continuous heat treatment furnace according to any one of claims 1 to 8 , wherein the conveying chain is made of ceramic.