JP7308601B2 - Heat treatment equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a technique for conveying a workpiece between a heating furnace and a quenching tank in a heat treatment apparatus.

Conventionally, in a quenching apparatus, which is one type of heat treatment apparatus, a workpiece heated in a heating furnace is transported to a position above a quenching tank using a guide rail or the like, and the workpiece is lowered from that position into the quenching tank. (see, for example, Patent Document 1). That is, in the conventional quenching apparatus, it was necessary to carry out a process of conveying the work to a position above the quenching bath and a process of lowering the work from that position. For this reason, it takes time from the completion of heating to the execution of cooling, which has been one of the causes of deterioration in the quality of the workpiece after quenching.

Japanese Utility Model Laid-Open No. 57-205264

Therefore, in the quenching apparatus, it has been considered to provide a quenching bath below the heating furnace and raise and lower a mounting table on which the work is placed between the heating furnace and the quenching bath. That is, by supporting the workpiece from below with the mounting table, the workpiece can be heated in the heating furnace and then immersed in the cooling liquid in the quenching bath together with the mounting table (or part thereof) to be cooled. It is considered.

However, the inventors have found that the quenching apparatus has the following problems. That is, since the mounting table (or part thereof) is immersed in the cooling liquid in the quenching tank, a large amount of cooling liquid adheres to the mounting table. Therefore, when the mounting table is transported into the heating furnace in the next step, a large amount of cooling liquid adhering to the mounting table is brought into the heating furnace, and the cooling liquid adversely affects the atmosphere in the heating furnace. There is fear.

Further, the lifting and lowering of the mounting table requires a large lifting device such as a device for lifting and lowering the mounting table by means of a rope member outside the heating furnace, a cylinder for lifting the mounting table from below, or the like. For example, when the mounting table is raised and lowered by a cylinder, the cylinder must be buried in the ground, forcing a large-scale installation work. Moreover, since the mounting table is arranged in the quenching tank, maintenance such as replacement is difficult. Furthermore, in order to increase the batch processing amount, it is necessary to increase the size of the mounting table, and as a result, the size of the quenching apparatus is increased.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve the quality of a workpiece after quenching in a heat treatment apparatus without increasing the size of the apparatus.

A heat treatment apparatus according to the present invention includes a heating furnace, a quenching tank provided below the heating furnace, and an elevating device for elevating a workpiece between the heating furnace and the quenching tank. The lifting device has a plurality of cable members for suspending and supporting a work, and a plurality of drive units that individually drive the plurality of cable members.

According to the above-described heat treatment apparatus, the work can be moved up and down with a simple structure in which the work is suspended by the rope member. In addition, when the work is lowered and immersed in the cooling liquid in the quenching tank, the entire work can be immersed in the cooling liquid without immersing the work and any part other than the cage that houses the work in the cooling liquid as much as possible. can. As a result, the amount of coolant adhering to portions other than the workpiece and the cage is reduced, and accordingly the amount of coolant brought into the heating furnace is reduced. Therefore, it is possible to reduce the adverse effect of the cooling liquid on the atmosphere in the heating furnace.

Further, according to the heat treatment apparatus, each of the plurality of cable members can be individually driven (including winding and unwinding). Therefore, it is possible to finely adjust the inclination, the conveying speed, the position, etc. of the work in consideration of the balance of the work. In addition, by using the rope member for conveying the work (including winding and feeding), the conveying speed can be increased compared to the case of conveying using a chain or the like. Therefore, the time (descent time) for moving the workpiece from the heating furnace to the quenching tank can be shortened.

The heat treatment apparatus may further include a detection section and a control section. Here, the detection section detects displacement of each cable member in the longitudinal direction caused by driving of the drive section corresponding to the cable member. The control section controls the plurality of drive sections based on the detection results of the detection section. Specifically, the control unit detects the inclination of the workpiece based on the relationship between the displacements obtained from the displacements detected by the detection unit for each of the plurality of cable members. More specifically, the control unit corrects the tilt of the work by controlling the plurality of drive units based on the detected tilt of the work. According to this configuration, even if the workpiece is tilted due to a difference in the length of the cable members due to some influence (for example, thermal influence from the heating furnace), the tilt is corrected before the start of descent. can be corrected.

In the above heat treatment apparatus, the ceiling of the heating furnace is provided with a plurality of through-holes through which the plurality of cable members are individually penetrated, and the lifting device is provided to the plurality of through-holes individually from the inside of the heating furnace. A plurality of rods that can be inserted may be further provided, the plurality of rods may be connected to the plurality of cable members, and the workpiece may be supported via the plurality of rods. In this configuration, it is preferable that a rod is inserted into each of the plurality of through-holes when the work is placed at a predetermined position in the heating furnace. This allows most of the space in each through-hole to be filled with the corresponding rod. Therefore, adverse effects on heating that can occur due to the provision of through holes (for example, disturbance of the atmosphere in the heating furnace, etc., caused by heat dissipation from the through holes, inflow of outside air from the through holes, etc. things) can be suppressed.

Further, in such a configuration, the detecting section can detect the displacement of each of the plurality of cable members connected to the plurality of rods by detecting the positions of each of the plurality of rods.

In the above heat treatment apparatus, each of the plurality of through-holes is provided with a seal plate that seals the periphery of the corresponding rod when the corresponding rod is inserted. Radially extending cuts may be provided. According to this configuration, the seal plate can prevent adverse effects on heating that may occur due to the provision of the through holes. Also, the existence of the notch allows the insertion of the rod even if it is inserted into the opening of the seal plate with a slight deviation. That is, by bending the periphery of the opening in the seal plate, the rod can be slid on the surface and moved to a predetermined position where it can be inserted into the opening.

In the above-described heat treatment apparatus, the elevating device may be provided with a path through which the cable member passes between the through hole and the driving section, corresponding to each of the plurality of cable members. The length of the path is preferably longer than the distance from the workpiece to the through hole when the workpiece is immersed in the quenching tank. According to this configuration, even when the workpiece is raised to the upper limit position (the position in the heating furnace) during winding of each cable member, the portion of the cable member passing through the heating furnace (that is, The part that may be heated in the heating furnace during quenching of the workpiece) does not wrap around the driving part. Therefore, it is possible to prevent an excessive load from being applied to the drive unit.

In the heat treatment apparatus described above, the control unit may be capable of adjusting the feeding speed of the corresponding cable members by controlling the plurality of driving units when the work is lowered. In this configuration, the control unit can reduce the delivery speed immediately before the work or the cage containing the work reaches the liquid level of the cooling liquid in the quenching bath, and increase the delivery speed after reaching the liquid level. preferable. According to this configuration, the work or cage can enter the coolant in the quenching bath at a low speed. Therefore, it is possible to suppress scattering of the cooling liquid when the workpiece or the cage enters the cooling liquid in the quenching tank. Further, by accelerating the work after the work or cage reaches the liquid surface of the cooling liquid, the descent time can be further shortened.

In the above heat treatment apparatus, the lifting device may further include a hanger capable of holding the work, and the work may be suspended and supported by the plurality of cable members via the hanger. According to this configuration, each cable member is connected to the hanger so that each cable member can be maintained in a vertically extended state when the workpiece is lifted or lowered regardless of the size of the workpiece. can be done.

Advantageous Effects of Invention According to the present invention, it is possible to improve the quality of a workpiece after quenching in a heat treatment apparatus without increasing the size of the apparatus.

1 is a conceptual diagram showing a heat treatment apparatus according to an embodiment; FIG. It is the figure which showed the state which made the cage immersed in the cooling liquid in a quenching tank. It is a top view of the hanger mechanism which a raising/lowering apparatus has. (A) An enlarged view of the IV area shown in FIG. 1, and (B) a top view of a seal plate. FIG. 3 is a block diagram showing a control unit and a configuration related thereto; It is the figure which showed the position of the rod controlled by correction processing. It is a conceptual diagram showing a modification of the heat treatment apparatus.

[1] Configuration of Heat Treatment Apparatus FIG. 1 is a conceptual diagram showing a heat treatment apparatus according to an embodiment. As shown in FIG. 1, the heat treatment apparatus of the present embodiment is an apparatus for quenching a workpiece whose main component is metal such as aluminum or steel. a device 3; As an example, the heat treatment apparatus is an apparatus that performs solution treatment on a work. In addition, in this embodiment, a plurality of works are collectively processed while being housed in the cage Cg. The heat treatment apparatus described below can be applied not only to solution treatment but also to various treatments in which cooling is performed immediately after heating.

The heating furnace 1 has a furnace wall 11 and heating means (not shown) such as an electric heater and a gas burner. A quenching bath 2 is provided below the heating furnace 1, and the bottom portion 11b of the furnace wall 11 has an opening 12 through which the cage Cg passes when the cage Cg is raised and lowered, and opening and closing of the opening 12 (Fig. 1 and FIG. 2) are provided.

A cooling liquid is stored in the quenching bath 2 . The quenching bath 2 is provided vertically below the opening 12 of the heating furnace 1 . Therefore, by lowering the cage Cg vertically downward from the heating furnace 1 through the opening 12 , the cage Cg can be immersed in the coolant in the quenching tank 2 . In this embodiment, water is used as the coolant. The coolant is not limited to water, and liquid such as oil may be used.

The elevating device 3 is a device for elevating the cage Cg between the heating furnace 1 and the quenching tank 2, and includes four ropes 31, a hanger mechanism 32, four driving units 33, a control unit 34, have

The four ropes 31 are for suspending the cage Cg from above and raising and lowering it. That is, the four ropes 31 are for suspending and supporting the cage Cg. The four ropes 31 are led into the heating furnace 1 through the top portion 11 a of the furnace wall 11 . Specifically, the top portion 11a is provided with four through-holes 11c (see FIG. 4A) through which the four ropes 31 are individually passed. is led into the heating furnace 1 through the . The rope 31 is an example of a cord member for suspending and supporting the cage Cg, and instead of the rope 31, a belt, cable, chain, or the like may be used as the cord member.

Each rope 31 has an appropriate heat resistance, and is less likely to be thermally damaged even when it is heated in the heating furnace 1 to the same extent as the work. Moreover, each rope 31 has an appropriate rigidity, so that when setting a route R of the rope 31 to a drum 331, which will be described later, the direction can be appropriately changed using a pulley or the like. For each rope 31, for example, a rope made of stainless steel can be used. It should be noted that ropes 31 other than those made of stainless steel may be used as long as they have appropriate heat resistance and rigidity. may

3 is a top view of the hanger mechanism 32. FIG. The hanger mechanism 32 is a mechanism for hanging the cage Cg from above with four ropes 31 (see FIG. 1), and includes a hanger portion 321 and four rods 322 .

The hanger portion 321 is composed of four hooks 321a and a support 321b that swingably supports the hooks 321a. Four receiving portions 41 (see FIG. 1) are provided on the top of the cage Cg, and the cage Cg is attached to the hanger portion 321 by individually hooking four hooks 321a on the four receiving portions 41. retained.

The four rods 322 can be individually inserted into the four through-holes 11 c from inside the heating furnace 1 , and their base ends are pivotally supported by the support 321 b of the hanger portion 321 . Specifically, each rod 322 has its base end rotatably supported by the support 321b so that the upper end can swing around the position where it is pivotally supported by the support 321b. ing. Also, the four rods 322 are pivotally supported by the support 321b in the same positional relationship as the four through holes 11c. One rope 31 is connected to each tip of the four rods 322 .

Furthermore, the length of each rod 322 is set as follows (see FIG. 4A). That is, when the cage Cg is arranged at a predetermined position in the heating furnace 1 for heating the workpiece, each rod 322 is inserted into the through-hole 11c and the tip of the rod 322 reaches the ceiling of the furnace wall 11. The length of each rod 322 is set so as to protrude upward from the portion 11a. Therefore, most of the space in each through hole 11c is blocked by the corresponding rod 322 when the cage Cg is placed in a predetermined position. Therefore, adverse effects on heating that may occur due to the provision of the through-hole 11c (for example, disturbance of the atmosphere in the heating furnace 1, etc., which are caused by heat dissipation from the through-hole 11c, inflow of outside air from the through-hole 11c, etc. ) can be suppressed. In this embodiment, the seal plate 14, which will be described later, further enhances the sealing performance to prevent adverse effects on heating.

According to the hanger mechanism 32, the cage Cg is suspended and supported by the four ropes 31 via the hanger mechanism 32 (the hanger portion 321 and the rod 322). Therefore, when cooling the workpiece, the entire cage Cg can be immersed in the cooling liquid without immersing parts other than the cage Cg in the cooling liquid as much as possible. In this embodiment, as shown in FIG. 2, the entire cage Cg can be immersed in the cooling liquid only by partially immersing each hook 321a in the cooling liquid. As a result, the amount of the cooling liquid adhering to the workpiece and portions other than the cage Cg is reduced. Become. Therefore, it is possible to reduce the adverse effect of the coolant on the atmosphere in the heating furnace 1 and improve the quality of the workpiece after quenching.

Further, according to the hanger mechanism 32, each rope 31 can be connected to the hanger portion 321 at a position vertically below the corresponding through hole 11c. Therefore, regardless of the size of the cage Cg (in this embodiment, the positions of the receiving portion 41 and the hooks 321a that change according to the size, etc.), the connection positions of the four ropes 31 to the hanger portion 321 are determined. The relationship can be maintained in the same relationship as the positional relationship of the four through holes 11c. That is, regardless of the size of the cage Cg, each rope 31 can be connected to the hanger portion 321 so that each rope 31 can be maintained in a vertically extended state when the cage Cg is raised and lowered. This makes it difficult for the ropes 31 to come into contact with the inner wall of the through hole 11c and the seal plate 14 (described later) when the cage Cg is raised and lowered.

FIG. 4A is an enlarged view of the IV area shown in FIG. As shown in FIG. 4A, in this embodiment, a seal plate 14 is provided in each through hole 11c. Specifically, the seal plate 14 seals the circumference of the rod 322 when the rod 322 is inserted into each through hole 11c. More specifically, it is as follows. 4B is a top view of the seal plate 14. FIG.

In the present embodiment, the seal plate 14 is sandwiched between two flat plate-shaped frames 121, and the frame 121 is fixed to the outer surface (upper surface) of the top portion 11a so that the seal plate 14 can move through the corresponding through holes. 11c from the outside. Further, as shown in FIG. 4B, the seal plate 14 is provided with an opening 14a through which the rod 322 is passed, and a plurality of notches 14b radially extending from the opening 14a. Here, the opening 14a has a shape that matches the cross-sectional shape of the rod 322, or a shape that is slightly larger than the cross-sectional shape of the rod 322 within the range where the necessary sealing performance can be achieved. A stainless steel plate, for example, can be used for the seal plate 14 . The sealing plate 14 is not limited to a stainless steel plate, and various flat plates having moderate heat resistance and moderate elasticity may be used.

According to such a seal plate 14, it is possible to prevent adverse effects on heating that may occur due to the provision of the through holes 11c. In addition, the presence of the notch 14b allows the insertion of the rod 322 even if it is inserted into the opening 14a with a slight deviation. That is, by bending the peripheral portion of the opening 14a, the rod 322 can be slid on the surface thereof to move the rod 322 to a predetermined position where it can be inserted into the opening 14a.

The four drive units 33 drive the four ropes 31 individually. Specifically, the four drive units 33 wind up the four ropes 31 individually. As shown in FIG. 1, each driving unit 33 includes a drum 331 for winding the rope 31, a servo motor 332 for rotating the drum 331, a servo driver 333 for controlling the rotation of the servo motor 332, including. Here, the servomotor 332 is composed of a rotary motor and an encoder (detector) (not shown). Then, the servo driver 333 feeds back the rotation angle (rotational position) of the rotation motor detected by the encoder and the rotation speed calculated from the rotation angle to the current, so that the rotation of the rotation motor is commanded from the control unit 34. It is controlled with high precision so that it rotates smoothly. As a result, the rotation angle and rotation speed of the drum 331 corresponding to the position and speed of the cage Cg are controlled with high accuracy.

With such four drive units 33, each drive (winding and unwinding) of the four ropes 31 can be performed individually. Therefore, it is possible to finely adjust the inclination, the transport speed, the position, etc. of the cage Cg in consideration of the balance of the cage Cg. Further, by using the rope 31 for transporting (winding and unwinding) the cage Cg, the transport speed can be increased compared to the transport using a chain or the like.

According to such a heat treatment apparatus, the work can be moved up and down with a simple structure in which the work is suspended by the ropes 31 . Therefore, an increase in device size is not caused.

Further, in this embodiment, a route R along which the rope 31 passes between the through hole 11 c and the drum 331 is set corresponding to each rope 31 . Specifically, the length of the route R is set to be longer than the distance L (see FIG. 2) from the cage Cg to the through hole 11c when the cage Cg is immersed in the quenching tank 2. is set. In this embodiment, the length of the route R to the drum 331 is made longer than the distance L by changing the direction of the rope 31 with three pulleys 334A to 334C. Also, by changing the direction of the rope 31, it becomes possible to construct a compact heat treatment apparatus. The distance L is the length of the rope 31 from the through hole 11c (in this embodiment, the length from the through hole 11c to the tip of the rod 322) when the cage Cg is immersed in the quenching tank 2. There may be.

According to the above setting of the route R, even when the cage Cg is raised to the upper limit position (the position in the heating furnace 1; see FIG. 1) when winding each rope 31, the heating furnace 1 (that is, a portion that may be heated in the heating furnace 1 during quenching of the workpiece) does not wrap around the drum 331 . As a comparative example, if the heated rope 31 is wound on the drum 331 as it is, the rope 31 cools and shrinks while being wound around the drum 331, so the drum 331 is tightened. For this reason, an excessive load is applied to the rope 31 and the drum 331, which may cause a reduction in strength or deterioration of the rope 31 and the drum 331. Therefore, by providing the path R described above, it is possible to prevent an excessive load from being applied to the driving section 33 .

The control unit 34 controls the four driving units 33 individually. Specifically, by controlling the four servo drivers 333 , the controller 34 individually or synchronously controls the four servo motors 332 through the four servo drivers 333 . A series of control processes performed by the control unit 34 can be performed by a processing device such as a CPU (Central Processing Unit) or a microcomputer. Also, the series of control processes may be realized by causing a processing device to execute a corresponding program. Then, such a program may be stored in a readable state in a storage medium (for example, flash memory, etc.), or may be stored in a storage unit (not shown) provided in the lifting device 3 . The control processing performed by the control unit 34 will be specifically described below.

FIG. 5 is a block diagram showing the control unit 34 and the configuration related thereto. In this embodiment, the control unit 34 uses information on the position of the cage Cg in the heating furnace 1 in addition to information on the rotation angle and rotation speed of the drum 331 obtained from each servo driver 333 to control each servo motor 332 to control. Specifically, the lifting device 3 further includes four first sensors 35A and four second sensors 35B as detection units (see FIG. 4A). The positions of the four rods 322 protruding upward from the four through holes 11c are individually detected by the four first sensors 35A and individually detected by the four second sensors 35B. More specifically, it is as follows.

Each first sensor 35A is a sensor that acquires information for determining the stop position of the cage Cg within the heating furnace 1 . Specifically, the first sensor 35A is provided above the through hole 11c through which the corresponding rod 322 passes, and when the upper end of the rod 322 reaches a predetermined height P1 (see FIG. 4A) , the upper end is detected and a detection signal is output. Here, the predetermined height P1 is the position that the upper end of the rod 322 reaches when the cage Cg reaches the stop position (that is, the predetermined position described above) within the heating furnace 1 . That is, when the first sensor 35A detects the upper end of the rod 322, it can be determined that the cage Cg has reached the stop position within the heating furnace 1 based on the detection result.

A fiber sensor, for example, can be used for the first sensor 35A. The first sensor 35A is not limited to the fiber sensor, and various sensors capable of detecting an object at a desired position may be used. Further, the first sensor 35A is not limited to the upper end of the rod 322, and may detect another portion of the rod 322 as a detection target.

Each second sensor 35B is a sensor that acquires information for determining the descent start position of the cage Cg within the heating furnace 1 . Specifically, the second sensor 35B is provided at a position higher than the first sensor 35A above the through hole 11c through which the corresponding rod 322 passes, and is positioned within a predetermined range S (see FIG. 4A) in the vertical direction. ), the position of the upper end of the rod 322 is detected, and a detection signal corresponding to the position is output. In this embodiment, the allowable range for the position of the upper end of the rod 322 when the cage Cg reaches the descent start position in the heating furnace 1 in the normal posture is detected in a partial area Sc of the predetermined range S. be. That is, when all the four first sensors 35A detect the upper end of the corresponding rod 322 within the area Sc, the cage Cg reaches the descent start position in the heating furnace 1 and the attitude at that time is normal. It can be determined that it is a posture.

A laser sensor, for example, can be used for the second sensor 35B. The second sensor 35B is not limited to the laser sensor, and various sensors capable of detecting the position of the object may be used. Further, the second sensor 35B is not limited to the position of the upper end of the rod 322, and the position of another part of the rod 322 may be the detection target.

[2] Control of Heat Treatment Apparatus In the control described below, the controller 34 controls the four servo motors 332 through the four servo drivers 333 . In controlling the four servo motors 332, the control unit 34 can switch between synchronous control and asynchronous control as necessary. Here, synchronous control is a control method for controlling the servo motors 332 so that the same operation is realized in all the servo motors 332 . Asynchronous control is a control method for controlling the servo motors 332 so that they operate individually.

[2-1] Conveying process (lifting process)
When raising the cage Cg, the control unit 34 synchronizes the rotation of the four drums 331 by controlling the four servomotors 332 in synchronization (synchronization control) to wind up the four ropes 31 (raising). process). When the controller 34 receives a detection signal from at least one of the four first sensors 35A, the controller 34 stops all the four servo motors 332, thereby stopping the cage Cg at a predetermined position (stop processing ). After that, the control unit 34 closes the door 13 before heating the workpiece in the heating furnace 1 . It should be noted that the transport processing (lifting processing) and stop processing described here can be executed by the transport processing section 341 (see FIG. 5) in the control section 34 . Further, the timing at which the control unit 34 executes the stop processing may be when detection signals are received from all the four first sensors 35A, or when detection signals are received from some of them. good.

[2-2] Correction Processing When the cage Cg is lowered into the quenching bath 2 after completion of heating of the workpiece, the control unit 34 moves the cage Cg to the lowering start position before starting lowering of the cage Cg. Specifically, the controller 34 individually controls the four servomotors 332 (asynchronous control) to wind the four ropes 31 at a low speed, thereby raising the cage Cg at a low speed.

After that, based on the detection signals output from the second sensors 35B when the cage Cg approaches the descent start position, the control unit 34 drives the servo motors 332 so that the positions of the upper ends of the rods 322 enter the area Sc. control (correction processing; see FIG. 6). Then, when the positions of the upper ends of all the four rods 322 enter the region Sc as a result of the control, the control unit 34 stops all the four servo motors 332 . As a result, even if the cage Cg is tilted due to a difference in the lengths of the ropes 31 due to some influence (for example, thermal influence from the heating furnace 1), the tilt is corrected before the descent starts. be able to. That is, the cage Cg can be arranged at the descent start position in a normal posture. Here, the normal posture is a posture that does not collide with the opening 12 (including the door 13 and the like) of the heating furnace 1 and the edge of the quenching tank 2 when the cage Cg is lowered. The correction processing described here can be executed by the correction processing section 342 (FIG. 5) in the control section 34. FIG.

By correcting the inclination of the cage Cg before the start of descent in this way, the cage Cg can be lowered in a normal posture. 12 (including the door 13 and the like) and the edge of the quenching tank 2 can be prevented from being hit.

Further, in the correction process described above, an appropriate allowable width (region Sc) is provided at the position of the upper end of the rod 322 that is adjusted during the correction process. Therefore, even if the position of one rod 322 is dragged by another rod 322 when the position of another rod 322 is adjusted, the positions of the upper ends of all four rods 322 are adjusted to the desired positions. (Position in area Sc) can be easily guided.

In this embodiment, the second sensor 35B can detect the position of the upper end of the rod 322 within a predetermined range S (see FIG. 4A) in the vertical direction. Therefore, the second sensor 35B can be understood as a detection unit that detects displacement in the longitudinal direction (here, the vertical direction) of the rope 31 caused by the driving of the drive unit 33 corresponding to each rope 31. . Specifically, the second sensor 35B detects the displacement of each of the four ropes 31 connected to the four rods 322 by detecting the positions of each of the four rods 322 . Then, the control unit 34 may detect the tilt of the workpiece based on the relationship between the displacements obtained from the displacements detected by the four second sensors 35B for the four ropes 31 . In this case, the control unit 34 (specifically, the correction processing unit 342) can correct the tilt of the work by controlling the four driving units 33 based on the detected tilt of the work.

[2-3] Conveying process (descent process)
When the cage Cg is lowered, the control unit 34 synchronizes the rotation of the four drums 331 by controlling the four servo motors 332 in synchronization after opening the door 13 (synchronous control). Pull out the rope 31 (descent process). At this time, the controller 34 adjusts the payout speed of the rope 31 corresponding to each by synchronizing and controlling the four servo motors 332 (synchronization control). Specifically, the control unit 34 causes the cage Cg to move at a high speed (sufficiently faster than when lowered using a chain or the like) until just before the cage Cg reaches the liquid surface of the cooling liquid in the quenching bath 2. including ). Thereby, the time (descent time) for moving the cage Cg from the heating furnace 1 to the quenching tank 2 can be shortened. Therefore, the quality of the workpiece after quenching can be improved.

Then, just before the cage Cg reaches the liquid surface of the cooling liquid in the quenching tank 2, the control unit 34 reduces the delivery speed to decelerate the cage Cg. After the cage Cg reaches the liquid surface of the cooling liquid, the controller 34 accelerates the cage Cg by increasing the delivery speed. At this time, the position of the cage Cg can be calculated from the rotation angle of the drum 331 obtained from each servo driver 333 . Therefore, the controller 34 compares the position of the cage Cg calculated from the rotation angle with the position of the liquid level of the cooling liquid in the quenching tank 2 so that the cage Cg reaches the liquid level of the cooling liquid. It can be determined whether it is just before or whether the cage Cg has reached the liquid surface of the cooling liquid. The transportation processing (lowering processing) described here can be executed by the transportation processing section 341 (see FIG. 5) in the control section .

In this way, when the cage Cg is lowered just before it reaches the liquid level of the cooling liquid in the quenching tank 2, it can enter the cooling liquid in the quenching tank 2 at a low speed. Therefore, when the cage Cg enters the cooling liquid in the quenching tank 2, the cooling liquid can be prevented from scattering. Further, by accelerating the cage Cg after reaching the liquid surface of the cooling liquid in the cage Cg, the descent time can be further shortened.

[3] Modification FIG. 7 is a conceptual diagram showing a modification of the heat treatment apparatus described above. In the heat treatment apparatus described above, the lifting device 3 is not limited to lifting and lowering the cage Cg by winding and unwinding the ropes 31. As shown in FIG. Further having a weight 335, for each rope 31, one of the pulleys (the pulley 334B in FIG. 7) on which the rope 31 is hung is driven by the servo motor 332 to raise and lower the cage Cg. good.

[4] Other Modifications In the heat treatment apparatus described above, the number of ropes 31 used for raising and lowering the cage Cg is not limited to four, and may be a plurality of ropes. The number of portions 33, rods 322, through holes 11c, etc.) can be changed.

In the heat treatment apparatus described above, the descent start position for moving the cage Cg in the correction process may be set below a predetermined position in the heating furnace 1 (the position where the cage Cg is arranged during heating). In this case, the second sensor 35B is provided at a position lower than the first sensor 35A.

Further, the heat treatment apparatus is characterized only in that the lifting device 3 has a plurality of ropes 31 for suspending the work from above and a plurality of drive units 33 for individually driving (rewinding) the plurality of ropes 31 respectively. It may be With this feature as the main feature, the above-described component configurations (including the control method) may be appropriately added partially or wholly to the heat treatment apparatus.

The description of the above-described embodiments should be considered illustrative in all respects and not restrictive. The scope of the invention is indicated by the claims rather than the above-described embodiments. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and range of equivalents of the claims.

1 heating furnace 2 quenching tank 3 lifting device 11 furnace wall 11a top 11b bottom 11c through hole 12 opening 13 door 14 seal plate 14a opening 14b notch 31 rope (cable member)
32 hanger mechanism 33 drive unit 34 control unit 35A first sensor 35B second sensor 41 receiver 121 frame 321 hanger 321a hook 321b support 322 rod 331 drum 332 servo motor 333 servo drivers 334A, 334B, 334C pulley 335 balance weight 341 transport processing unit 342 correction processing unit L distance R path S predetermined range Cg cage Sc area

Claims (9)

a heating furnace;
a quenching bath provided below the heating furnace;
a lifting device for lifting the workpiece between the heating furnace and the quenching tank;
with
The lifting device is
a plurality of cable members for suspending and supporting the workpiece;
a plurality of drive units that individually drive the plurality of cable members;
has
The lifting device is
a detection unit for detecting, for each of the cable members, displacement in the longitudinal direction of the cable member caused by driving of the drive unit corresponding to the cable member;
a control unit that controls the plurality of drive units based on the detection results of the detection unit;
further having
The heat treatment apparatus, wherein the control unit detects the inclination of the workpiece based on a relationship between the displacements obtained from the displacements detected by the detection unit for the plurality of cable members. The heat treatment apparatus according to claim 1, wherein the control section corrects the tilt of the work by controlling the plurality of drive sections based on the detected tilt of the work. 3. The heat treatment apparatus according to claim 2 , wherein correction of inclination of said work is performed between one heat treatment process and another heat treatment process performed after said one heat treatment process. The ceiling of the heating furnace is provided with a plurality of through-holes for individually penetrating the plurality of cable members,
The lifting device further includes a plurality of rods that can be individually inserted into the plurality of through holes from within the heating furnace, and the plurality of rods are connected to the plurality of cable members, respectively,
4. The heat treatment apparatus according to claim 1 , wherein said workpiece is supported via said plurality of rods. The heat treatment apparatus according to claim 4 , wherein the detection unit detects the displacement of each of the plurality of cable members connected to the plurality of rods by detecting the positions of each of the plurality of rods. . Each of the plurality of through-holes is provided with a seal plate that seals the periphery of the rod when the corresponding rod is inserted,
6. The heat treatment apparatus according to claim 4 , wherein the seal plate is provided with an opening through which the rod is passed and cuts extending radially from the opening. A route through which the cable member passes between the through hole and the driving unit is set in the lifting device, corresponding to each of the plurality of cable members,
7. The heat treatment apparatus according to claim 4 , wherein the length of said path is greater than the distance from said work to said through hole when said work is immersed in said quenching bath. The control unit is capable of adjusting the feeding speed of the corresponding cable member by controlling the plurality of driving units when the work is lowered, and the work or the work is accommodated. 4. The heat treatment apparatus according to any one of claims 1 to 3 , wherein the feeding speed is reduced immediately before the cage reaches the liquid surface of the cooling liquid in the quenching bath, and the feeding speed is increased after reaching the liquid surface. The lifting device further has a hanger capable of holding the work,
The heat treatment apparatus according to any one of claims 1 to 8 , wherein the work is suspended and supported by the plurality of cable members via the hanger portion.

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