JP2020045533A - Heat treatment apparatus - Google Patents

Abstract

To improve the quality of a workpiece by quenching in a heat treatment apparatus without increasing the size of the apparatus.SOLUTION: The heat treatment apparatus includes a heating furnace 1, a quenching bath 2 arranged below the heating furnace 1, and an elevator 3 for lifting the workpiece between the heating furnace 1 and the quenching bath 2. The elevator 3 includes a plurality of cable members 31 for suspending and supporting the workpiece, and a plurality of driving units 33 for individually driving the plurality of cable members 31.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for transferring a work between a heating furnace and a quenching tank in a heat treatment apparatus.

  Conventionally, in a quenching apparatus, which is one of the heat treatment apparatuses, a work heated in a heating furnace is transported to a position above a quenching tank using a guide rail or the like, and the work is lowered from the position and the inside of the quenching tank is cooled. (See, for example, Patent Document 1). That is, in the conventional quenching apparatus, it is necessary to execute a step of transporting the work to a position above the quenching tank and a step of lowering the work from the position. For this reason, it takes time from the completion of the heating to the execution of the cooling, which is one of the causes of deteriorating the quality of the quenched work.

JP-A-57-205264

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

  However, the present inventors have found that the above quenching apparatus has the following problems. That is, since the mounting table (or a part thereof) is immersed in the cooling liquid in the quenching tank, a large amount of the cooling liquid adheres to the mounting table. For this reason, when the mounting table is transported into the heating furnace in the next step, a large amount of the coolant 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 a fear.

  Further, in order to raise and lower the mounting table, a large lifting apparatus such as a device for hanging the mounting table outside the heating furnace with a cable member to raise and lower the mounting table and a cylinder for lifting the mounting table from below is required. For example, when the mounting table is moved up and down by a cylinder, the cylinder must be buried in the ground, and a large-scale installation operation is required. Further, since the mounting table is arranged in the quenching tank, maintenance such as replacement is difficult. Furthermore, if it is intended to increase the amount to be processed collectively, the mounting table needs to be enlarged, and as a result, the quenching device becomes large.

  Accordingly, an object of the present invention is to improve the quality of a quenched work without increasing the size of the heat treatment apparatus.

  The 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 and lowering a workpiece between the heating furnace and the quenching tank. The elevating device includes a plurality of cable members for suspending and supporting a work, and a plurality of driving units for individually driving the plurality of cable members.

  According to the heat treatment apparatus described above, the work can be raised and lowered with a simple configuration in which the work is hung by the cable member. When the work is lowered and immersed in the cooling liquid in the quenching bath, it is possible to immerse the entire work in the cooling liquid without immersing the work and parts other than the cage for storing the work in the cooling liquid as much as possible. it can. This reduces the amount of coolant adhering to parts other than the work and the cage, and therefore reduces the amount of coolant brought into the heating furnace. Therefore, the adverse effect on the atmosphere in the heating furnace due to the cooling liquid can be reduced.

  Further, according to the heat treatment apparatus, it is possible to individually drive (including winding and feeding) each of the plurality of cable members. Therefore, the inclination, the transfer speed, the position, and the like of the work can be finely adjusted in consideration of the balance of the work and the like. In addition, by using the cord member for transporting the work (including winding and unwinding), the transport speed can be increased as compared with the case where the transport is performed using a chain or the like. Therefore, it is possible to reduce the time required for moving the work from the heating furnace to the quenching tank (falling time).

  In the above-described heat treatment apparatus, a detection unit and a control unit may be further included. Here, the detection unit detects, for each cable member, a displacement in the longitudinal direction of the cable member caused by driving of the corresponding drive unit. The control unit controls the plurality of driving units based on a detection result by the detection unit. Specifically, 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. More specifically, the control unit corrects the work inclination by controlling the plurality of driving units based on the detected work inclination. According to this configuration, even if a difference occurs in the length of each of the cord members due to some influence (for example, thermal influence from a heating furnace) and the work is inclined, the inclination is reduced before the descent starts. Can be corrected.

  In the heat treatment apparatus, the top of the heating furnace is provided with a plurality of through holes for individually penetrating a plurality of cable members, and the elevating device is individually provided to the plurality of through holes from inside the heating furnace. It may further have a plurality of rods that can be inserted, the plurality of rods may be respectively connected to the plurality of cable members, and the work may be supported via the plurality of rods. In this configuration, when the work is arranged at a predetermined position in the heating furnace, it is preferable that a rod is inserted into each of the plurality of through holes. Thus, most of the space in each through hole can be closed by the corresponding rod. Therefore, adverse effects on heating that may occur due to the provision of the through holes (for example, disturbance of the atmosphere in the heating furnace or the like, which are caused by heat radiation from the through holes, inflow of outside air from the through holes, and the like) ) Can be suppressed.

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

  In the heat treatment apparatus, each of the plurality of through holes is provided with a seal plate that seals around the rod when the corresponding rod is inserted, and the seal plate has an opening through which the rod passes, and Radially extending cuts may be provided. According to this configuration, the seal plate can prevent adverse effects on heating that may be caused by providing the through holes. In addition, even if the rod is slightly shifted and inserted into the opening of the seal plate due to the presence of the cut, the insertion is allowed. That is, by bending the peripheral portion of the opening in the seal plate, the rod can be slid on the surface thereof, and the rod can be moved to a predetermined position where insertion into the opening is possible.

  In the heat treatment apparatus, a path through which the cable member passes between the through hole and the drive unit may be set in the lifting device in correspondence with each of the plurality of cable members. The length of the path is preferably larger than the distance from the work to the through hole when the work is immersed in the quenching tank. According to this configuration, even when the work is raised to the upper limit position (the position in the heating furnace) at the time of winding each cable member, a portion of the cable member passing through the heating furnace (ie, The part that may be heated by the heating furnace during the quenching of the work) does not wind around the drive unit. Therefore, it is possible to prevent an excessive load from being applied to the driving unit.

  In the heat treatment apparatus, the control unit may be capable of adjusting the feeding speed of the corresponding rope member by controlling the plurality of driving units when the workpiece is lowered. In this configuration, the control unit may reduce the feeding speed just before the work or the cage storing the work reaches the liquid level of the cooling liquid in the quenching tank, and increase the feeding speed after reaching the liquid level. preferable. According to this configuration, the work or the cage can enter the cooling liquid in the quenching tank at a low speed. Therefore, scattering of the cooling liquid when the work or the cage enters the cooling liquid in the quenching tank can be suppressed. Further, after the work or the cage reaches the liquid level of the cooling liquid, the work is accelerated, so that the descent time can be further shortened.

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

  According to the present invention, it is possible to improve the quality of a quenched work without increasing the size of the heat treatment apparatus.

It is a key map showing the heat treatment equipment concerning an embodiment. It is the figure which showed the state where the cage was immersed in the cooling liquid in a quenching tank. It is a top view of the hanger mechanism which a raising / lowering device has. 4A is an enlarged view of an IV region shown in FIG. 1 and FIG. 4B is a top view of a seal plate. FIG. 3 is a block diagram illustrating a control unit and a configuration related thereto. It is a figure showing the position of the rod controlled by correction processing. It is the conceptual diagram which showed the modification of the heat processing apparatus.

[1] Configuration of Heat Treatment Apparatus FIG. 1 is a conceptual diagram showing a heat treatment apparatus according to the embodiment. As shown in FIG. 1, the heat treatment apparatus of the present embodiment is an apparatus for quenching a work mainly containing a metal such as aluminum or steel, and includes a heating furnace 1, a quenching tank 2, Device 3. As an example, the heat treatment apparatus is an apparatus that performs a solution treatment on a workpiece. Further, in the present embodiment, a plurality of works are collectively processed while being stored in the cage Cg. Note that the heat treatment apparatus described below can be applied not only to the solution treatment but also to various kinds of processing for cooling 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 tank 2 is provided below the heating furnace 1, and an opening 12 through which the cage Cg passes when the cage Cg is moved up and down, and an opening and closing of the opening 12 are provided on the bottom 11 b of the furnace wall 11 (see FIG. 1 and FIG. 2) are provided.

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

  The lifting device 3 is a device that raises and lowers 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, Having.

  The four ropes 31 are for suspending the cage Cg from above and moving it up and down. That is, the four ropes 31 are for suspending and supporting the cage Cg. Then, the four ropes 31 penetrate the ceiling 11 a of the furnace wall 11 and are guided into the heating furnace 1. Specifically, the top portion 11a is provided with four through holes 11c (see FIG. 4A) through which the four ropes 31 are individually penetrated, and each rope 31 has a corresponding through hole 11c. To the heating furnace 1. The rope 31 is an example of a rope member for suspending and supporting the cage Cg. Instead of the rope 31, a belt, a cable, a chain, or the like may be used as the rope member.

  Each rope 31 has an appropriate heat resistance, and is hardly thermally damaged even when heated in the heating furnace 1 to the same degree as the work. Each rope 31 has appropriate rigidity. Therefore, when setting a route R of the rope 31 to the drum 331 described later, the direction can be appropriately changed using a pulley or the like. As each rope 31, for example, a rope made of stainless steel can be used. In addition, as long as it has appropriate heat resistance and appropriate rigidity, a rope 31 other than stainless steel may be used, or a rope member such as a belt, a cable, or a chain is used instead of the rope 31. You may.

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

  The hanger part 321 includes four hooks 321a and a support 321b that supports the hooks 321a in a swingable manner. Four receiving portions 41 (see FIG. 1) are provided on the top portion of the cage Cg, and the four hooks 321a are individually hooked on the four receiving portions 41, respectively, so that the cage Cg is mounted on the hanger portion 321. Will be retained.

  The four rods 322 can be individually inserted into the four through holes 11c from inside the heating furnace 1, and the base ends of the four rods 322 are supported by the support 321b of the hanger part 321. Specifically, the base end of each rod 322 is rotatably supported by the support 321b so that the upper end can swing about a position supported by the support 321b. ing. The four rods 322 are supported by the support 321b in the same positional relationship as the positional relationship of the four through holes 11c. One end of each of the four rods 322 is connected to one rope 31.

  Further, 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 in order to execute the heating of the workpiece, each rod 322 is inserted into the through hole 11c, and the tip of the rod 322 is attached to the top of the furnace wall 11. The length of each rod 322 is set so as to protrude upward from the portion 11a. Therefore, when the cage Cg is arranged at a predetermined position, most of the space in each through hole 11c is closed by the corresponding rod 322. Therefore, adverse effects on heating that may occur due to the provision of the through-holes 11c (for example, disturbance of the atmosphere in the heating furnace 1 due to heat radiation from the through-holes 11c or inflow of outside air from the through-holes 11c). Which occurs as a result) can be suppressed. In the present embodiment, a sealing plate 14 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 part 321 and the rod 322). Therefore, when cooling the work, 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 the present embodiment, as shown in FIG. 2, only the part of each hook 321a is immersed in the coolant, and the entire cage Cg can be immersed in the coolant. As a result, the amount of the coolant adhering to parts other than the work and the cage Cg is reduced, and therefore, the amount of the coolant brought into the heating furnace 1 when the next work is transported into the heating furnace 1 is reduced. Become. Therefore, the adverse effect on the atmosphere in the heating furnace 1 due to the coolant can be reduced, and the quality of the quenched work can be improved.

  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 and the like (in the present embodiment, the positions of the receiving portion 41 and the hook 321a that change according to the size and the like), the connection position of the four ropes 31 to the hanger portion 321 is determined. The relationship can be maintained in the same relationship as the positional relationship between the four through holes 11c. That is, regardless of the size of the cage Cg, each rope 31 can be connected to the hanger part 321 such that the state of each rope 31 can be maintained in a vertically extended state when the cage Cg is raised and lowered. This makes it difficult for each rope 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 moves up and down.

  FIG. 4A is an enlarged view of the IV region 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 around the rod 322 when the rod 322 is inserted into each through hole 11c. More specifically, it is as follows. FIG. 4B is a top view of the seal plate 14.

  In the present embodiment, the seal plate 14 is sandwiched between two flat frame members 121, and the frame member 121 is fixed to the outer surface (upper surface) of the top portion 11a. 11c is provided from the outside. Further, as shown in FIG. 4B, the seal plate 14 is provided with an opening 14a through which the rod 322 passes, and a plurality of cuts 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 a range that can achieve the required sealing performance. As the seal plate 14, for example, a stainless steel plate can be used. Note that the seal plate 14 is not limited to a stainless steel plate, and various flat plates having appropriate heat resistance and appropriate elasticity may be used.

  According to such a seal plate 14, it is possible to prevent adverse effects on heating that may be caused by providing the through holes 11c. Further, even if the rod 322 is slightly shifted and inserted into the opening 14a due to the presence of the cut 14b, the insertion is allowed. That is, when the peripheral portion of the opening 14a bends, the rod 322 can slide on the surface thereof, and the rod 322 can be moved to a predetermined position where the rod 322 can be inserted into the opening 14a.

  The four driving units 33 individually drive the four ropes 31 respectively. Specifically, the four driving units 33 individually wind the four ropes 31 respectively. 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 servo motor 332 includes a rotation motor and an encoder (detector) (not shown). Then, the servo driver 333 instructs the control unit 34 to rotate the rotation motor by feeding back the rotation angle (rotation position) of the rotation motor detected by the encoder and the rotation speed calculated from the rotation angle to the current. Control with high accuracy so that the rotation is Thereby, the rotation angle and the rotation speed of the drum 331 corresponding to the position and the speed of the cage Cg are accurately controlled.

  According to the four driving units 33, the driving (winding and feeding) of the four ropes 31 can be individually performed. Therefore, the tilt, the transport speed, the position, and the like of the cage Cg can be finely adjusted in consideration of the balance of the cage Cg. Further, by using the ropes 31 for transporting (winding and feeding) of the cage Cg, the transport speed can be increased as compared with the case where transport is performed using a chain or the like.

  According to such a heat treatment apparatus, the work can be raised and lowered with a simple configuration such as hanging the work with the rope 31. Therefore, the size of the apparatus is not increased.

  Further, in the present embodiment, a route R through which the rope 31 passes is set between the through hole 11c and the drum 331 so as to correspond to each rope 31. Specifically, the route R is set so that the length of the route R is larger 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 the present embodiment, the length of the path R to the drum 331 is made larger than the distance L by changing the direction of the rope 31 with the three pulleys 334A to 334C. Further, by changing the direction of the rope 31, a compact heat treatment apparatus can be constructed. Note that the distance L is the length of the rope 31 from the through hole 11c when the cage Cg is immersed in the quenching tank 2 (in this embodiment, the length from the through hole 11c to the tip of the rod 322). 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) at the time of winding each rope 31, the heating furnace of the rope 31 1 (that is, a part that may be heated by the heating furnace 1 during quenching of the work) does not wind around the drum 331. As a comparative example, if the heated rope 31 is taken up by 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 the rope 31 and the drum 331 to decrease in strength or deteriorate. Therefore, by providing the above-described route R, it is possible to prevent an excessive load from being applied to the driving unit 33.

  The control unit 34 controls the four driving units 33 individually. Specifically, the control unit 34 controls the four servo drivers 333 to control the four servo motors 332 individually or in synchronization 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. Further, the series of control processes may be realized by causing a processing device to execute a corresponding program. Such a program may be stored in a readable state on a storage medium (for example, a flash memory or the like), or may be stored on a storage unit (not shown) provided in the lifting device 3. Hereinafter, the control processing performed by the control unit 34 will be specifically described.

  FIG. 5 is a block diagram illustrating the control unit 34 and a configuration related thereto. In the present embodiment, the control unit 34 uses the information on the position of the cage Cg in the heating furnace 1 in addition to the information on the rotation angle and the rotation speed of the drum 331 obtained from each servo driver 333, and Control. Specifically, the elevating device 3 further includes four first sensors 35A and four second sensors 35B as detection units (see FIG. 4A). Then, the positions of the four rods 322 projecting upward from the four through holes 11c are individually detected by the four first sensors 35A, respectively, 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 a stop position of the cage Cg in 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). Then, the upper end is detected and a detection signal is output. Here, the predetermined height P1 is a position where the upper end of the rod 322 reaches when the cage Cg reaches the stop position in the heating furnace 1 (that is, the above-described predetermined position). 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 in the heating furnace 1 based on the detection result.

  As the first sensor 35A, for example, a fiber sensor can be used. Note that the first sensor 35A is not limited to a 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 a descent start position of the cage Cg in 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 has a predetermined range S in the vertical direction (see FIG. 4A). ), The position of the upper end of the rod 322 is detected, and a detection signal corresponding to the position is output. In the present embodiment, a range allowable as 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 a normal posture is detected in a partial region Sc of the predetermined range S. You. That is, when all the four first sensors 35A detect the upper ends of the corresponding rods 322 in the region Sc, the cage Cg reaches the descent start position in the heating furnace 1 based on the detection result, and the posture at that time is normal. The posture can be determined.

  For example, a laser sensor can be used as the second sensor 35B. Note that the second sensor 35B is not limited to a laser sensor, and various sensors capable of detecting the position of an object may be used. Further, the second sensor 35B is not limited to the position of the upper end of the rod 322, and may detect the position of another portion of the rod 322 as a detection target.

[2] Control of Heat Treatment Apparatus In the control described below, the control unit 34 controls four servo motors 332 through four servo drivers 333. When controlling the four servo motors 332, the control unit 34 can switch between the synchronous control and the asynchronous control as necessary and execute the control. Here, the 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. The asynchronous control is a control method for controlling the servo motors 332 so that the servo motors 332 operate individually.

[2-1] Transport processing (elevation processing)
When raising the cage Cg, the control unit 34 controls the four servo motors 332 in synchronization with each other (synchronization control), thereby synchronizing the rotations of the four drums 331 and winding up the four ropes 31 (raising). processing). Then, when receiving the detection signal from at least one of the four first sensors 35A, the control unit 34 stops the cage Cg at a predetermined position by stopping all four servomotors 332 (stop processing). ). Thereafter, the control unit 34 closes the door 13 before performing heating of the work in the heating furnace 1. The transfer processing (elevation processing) and the stop processing described here can be executed by the transfer processing unit 341 (see FIG. 5) in the control unit 34. The timing at which the control unit 34 executes the stop processing may be when the detection signals are received from all the four first sensors 35A, or when the detection signals are received from some of them. Good.

[2-2] Correction Process When the cage Cg is lowered into the quenching tank 2 after the heating of the work is completed, the control unit 34 moves the cage Cg to the descent start position before starting the descent of the cage Cg. Specifically, the control unit 34 controls the four servo motors 332 individually (asynchronous control) to wind up the four ropes 31 at a low speed, thereby raising the cage Cg at a low speed.

  Thereafter, the control unit 34 controls the servo motor 332 so that the upper end position of each rod 322 enters the region Sc based on the detection signal output from each second sensor 35B when the cage Cg approaches the descent start position. 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 servomotors 332. Thereby, even if a difference occurs in the length of each of the ropes 31 due to some influence (for example, thermal influence from the heating furnace 1) and the cage Cg is inclined, the inclination is corrected before the descent starts. be able to. That is, the cage Cg can be arranged at the descent start position in the 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 unit 342 (FIG. 5) in the control unit 34.

  In this manner, by correcting the inclination of the cage Cg before the descent starts, the cage Cg can be lowered in the normal posture, and as a result, the opening of the heating furnace 1 that can be generated if the cage Cg is tilted 12 (including the door 13) and the edge of the quenching tank 2 can be prevented from colliding.

  In the above-described correction processing, an appropriate allowable width (area Sc) is provided at the position of the upper end of the rod 322 adjusted during the correction processing. Therefore, even if the position of a certain rod 322 may be shifted by being dragged when the position of another rod 322 is adjusted, the positions of the upper ends of all the four rods 322 are set to the desired positions. (A position within the region Sc).

  In the present 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 35 </ b> B can be understood as a detecting unit that detects, for each rope 31, a displacement in the longitudinal direction (here, the vertical direction) of the rope 31 caused by driving the corresponding driving unit 33. . Specifically, the second sensor 35B detects the displacement of each of the four ropes 31 connected to the four rods 322 by detecting the position of each of the four rods 322. Then, the control unit 34 may detect the inclination 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, respectively. In this case, the control unit 34 (specifically, the correction processing unit 342) can correct the inclination of the work by controlling the four driving units 33 based on the detected inclination of the work.

[2-3] Transport processing (downward processing)
When lowering the cage Cg, after opening the door 13, the control unit 34 controls the four servo motors 332 in a synchronized manner (synchronous control), thereby synchronizing the rotations of the four drums 331 to the four drums 331. The rope 31 is paid out (descent processing). At this time, the control unit 34 adjusts the feeding speed of the rope 31 corresponding to each by controlling the four servo motors 332 in synchronization (synchronous control). Specifically, the control unit 34 moves the cage Cg at a high speed (immediately before the cage Cg reaches the liquid level of the cooling liquid in the quenching tank 2, which is sufficiently faster than when the cage Cg is lowered using a chain or the like). ). Thereby, the time (fall time) for moving the cage Cg from the heating furnace 1 to the quenching tank 2 can be reduced. Therefore, the quality of the work after quenching can be improved.

  Then, immediately before the cage Cg reaches the liquid level of the cooling liquid in the quenching tank 2, the control unit 34 reduces the feeding speed to reduce the speed of the cage Cg. Then, after the cage Cg reaches the liquid level of the cooling liquid, the controller 34 accelerates the cage Cg by increasing the feeding 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 control unit 34 compares the position of the cage Cg calculated from the rotation angle with the position of the liquid level of the coolant in the quenching tank 2 so that the cage Cg reaches the level of the coolant. It can be determined whether it is immediately before or whether the cage Cg has reached the level of the coolant. Note that the transfer processing (downward processing) described here can be executed by the transfer processing unit 341 (see FIG. 5) in the control unit 34.

  In this way, by lowering the cage Cg immediately before reaching the liquid level of the cooling liquid in the quenching tank 2 when descending, it is possible to enter the cooling liquid in the quenching tank 2 at a low speed. Therefore, scattering of the cooling liquid when the cage Cg enters the cooling liquid in the quenching tank 2 can be suppressed. Further, by accelerating the cage Cg after reaching the liquid level of the cooling liquid in the cage Cg, it is possible to further shorten the descent time.

[3] Modification FIG. 7 is a conceptual diagram showing a modification of the above-described heat treatment apparatus. In the heat treatment apparatus described above, the lifting device 3 is not limited to the device that raises and lowers the cage Cg by winding and unwinding the rope 31, and the balance that balances with the cage Cg via the four ropes 31 as shown in FIG. A weight 335 is further provided, and 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 servomotor 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 may be a plurality of ropes, not limited to four. The number of the parts 33, the rods 322, the through holes 11c, etc.) can be changed.

  In the heat treatment apparatus described above, the descent start position at which the cage Cg is moved in the correction processing may be set below a predetermined position in the heating furnace 1 (position at which 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 in that the elevating device 3 only has a plurality of ropes 31 for suspending the work from above, and a plurality of driving units 33 for individually driving (winding) the plurality of ropes 31. May be used. The above-described components (including the control method) may be partially or wholly added to the heat treatment apparatus, with this feature as the main feature.

  The description of the above embodiment is illustrative in all aspects and should not be construed as limiting. The scope of the present invention is defined by the terms of the claims, rather than the embodiments described above. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the claims.

DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Quenching tank 3 Elevating device 11 Furnace wall 11a Top part 11b Bottom part 11c Through hole 12 Opening 13 Door 14 Seal plate 14a Opening 14b Cut 31 Rope (cord 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 driver 334A, 334B, 334C Pulley 335 Balance weight 341 Transport processing unit 342 Correction processing unit L Distance R Route S Predetermined range Cg Cage Sc area

Claims (9)

Heating furnace,
A quenching tank provided below the heating furnace,
An elevating device for elevating and lowering the work between the heating furnace and the quenching tank,
With
The lifting device,
A plurality of cable members for suspending and supporting the work,
A plurality of driving units for individually driving the plurality of cable members,
, A heat treatment apparatus. The lifting device,
For each of the cable members, a detection unit that detects a displacement in the longitudinal direction of the cable member caused by driving of the corresponding drive unit,
A control unit that controls the plurality of driving units based on a detection result by the detection unit;
Further having
2. The heat treatment apparatus according to claim 1, wherein the control unit detects the inclination of the work based on a relationship between the displacements obtained from the displacements detected by the detection unit with respect to the plurality of cable members. 3.   The heat treatment apparatus according to claim 2, wherein the control unit corrects the inclination of the work by controlling the plurality of driving units based on the detected inclination of the work. A plurality of through holes for individually penetrating the plurality of cable members are provided in a top portion of the heating furnace,
The elevating device further includes a plurality of rods that can be individually inserted into the plurality of through holes from inside the heating furnace, and the plurality of rods are respectively connected to the plurality of cable members.
The heat treatment apparatus according to claim 2, wherein the work is supported via the plurality of rods.   5. 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 a position of each of the plurality of rods. 6. . Each of the plurality of through holes is provided with a seal plate that seals around the rod when the corresponding rod is inserted,
The heat treatment apparatus according to claim 4, wherein the seal plate is provided with an opening through which the rod passes and a cut radially extending from the opening. In the elevating device, a path that the cable member passes between the through hole and the driving unit is set in correspondence with each of the plurality of cable members,
The heat treatment apparatus according to claim 4, wherein a length of the path is larger than a distance from the work to the through hole when the work is immersed in the quenching tank.   The control unit is capable of adjusting the feeding speed of the cable member corresponding to each of the plurality of driving units by controlling the plurality of driving units when the work is lowered, and stores the work or the work. The heat treatment apparatus according to any one of claims 2 to 7, wherein the feed rate is reduced immediately before the cage reaches the liquid level of the cooling liquid in the quenching tank, and the feed rate is increased after the cage reaches the liquid level. The elevating device further includes a hanger portion capable of holding the work,
The heat treatment apparatus according to claim 1, wherein the work is suspended and supported by the plurality of cord members via the hanger portion.

Images