JP7432549B2 - Batch heat treatment furnace - Google Patents

Description

The technology disclosed herein relates to a batch heat treatment furnace for heat treating objects to be treated (for example, laminated ceramic parts such as ceramic capacitors, ceramic piezoelectric elements, ceramic resistors, etc.).

For example, Patent Document 1 discloses a batch-type heat treatment furnace for heat-treating a workpiece. The batch heat treatment furnace disclosed in Patent Document 1 includes a furnace body including a ceiling wall, side walls, and an elevating floor, a processing table provided on the elevating floor, and a drive device that rotationally drives the processing table. The object to be processed is placed on the processing table. The elevating floor is movable between a first position where the lower end of the side wall is open and a second position where the lower end of the side wall is closed. When placing a workpiece in a batch-type heat treatment furnace, first, the elevating floor is moved to a first position, and the workpiece is placed on a processing table. Then, the processing table (that is, the elevating floor) on which the object to be processed is placed is moved from the first position to the second position. Thereby, the object to be processed is placed inside the furnace body.

Japanese Patent Application Publication No. 2005-77001

In the batch type heat treatment furnace of Patent Document 1, the elevating floor is moved from the first position to the second position with the workpiece placed on the processing table. At this time, if the object to be processed is placed on the processing table in a state that deviates from the predetermined standard placement state, the object to be processed will be Contact with the furnace body. Therefore, such a shift of the object to be processed can be corrected by visually checking it by the operator. However, when the workpiece is moved from the first position to the second position on the elevating floor, it may be slightly shifted to the extent that it does not come into contact with the furnace body. Although such a slight deviation does not affect the placement of the workpiece in the furnace body, the rotation of the processing table during heat treatment increases the deviation, making it difficult to contact the furnace body during heat treatment. It may cause It was difficult for an operator to visually confirm such a slight deviation.

This specification discloses a technique for preventing a workpiece from coming into contact with a furnace body.

The batch heat treatment furnace disclosed herein includes a furnace body including a ceiling wall, a side wall, and an elevating floor, a processing table that is rotatably arranged with respect to the elevating floor and on which a workpiece can be placed, and an elevating and elevating floor. It is provided on the floor and includes a drive device that rotationally drives the processing table, and a sensor that detects a deviation of the workpiece placed on the processing table from a reference placement state. The elevating floor is movable between a first position where the lower end of the side wall is open and a second position where the lower end of the side wall is closed. When the elevating floor is located at the second position, the upper surface of the processing table is exposed within the furnace body. The sensor is arranged to detect displacement of the workpiece placed on the processing table when the elevating floor is located at the first position. The sensor detects displacement of the object to be processed when the elevating floor is located at the first position and the drive device is rotating the processing table.

In the above-mentioned batch type heat treatment furnace, the processing table is rotated when the elevating floor is located at the first position, and the sensor detects deviation from the standard mounting state of the processing object. Therefore, by rotating the processing table during heat treatment, it is possible to detect in advance that the object to be processed comes into contact with the furnace body. Furthermore, positional deviation is detected while the processing table is rotated. Therefore, for example, even if the detection sensor is fixedly arranged, it is possible to detect displacement over the entire circumference of the processing table.

FIG. 1 is a cross-sectional view showing a schematic configuration of a heat treatment furnace according to an example (a state in which the elevating floor is lowered). FIG. 1 is a cross-sectional view showing a schematic configuration of a heat treatment furnace according to an example (a state in which an elevating floor is raised). FIG. 2 is a cross-sectional view of a heat treatment furnace in which a processing table is installed (III-III cross-sectional view in FIG. 2). FIG. 2 is a side view showing a state in which a processing table is installed on an elevating floor (however, illustration of the drive device (20, 22) is omitted). FIG. 5 is a plan view showing a state in which the processing table is installed on the elevating floor (a view of the processing table and the elevating floor viewed from above in FIG. 4); FIG. 3 is a schematic diagram showing a schematic configuration of a connecting section that connects a processing table and a drive mechanism (a diagram showing a state in which the processing table and drive mechanism are not connected); FIG. 3 is a schematic diagram showing a schematic configuration of a connecting section that connects a processing table and a drive mechanism (a diagram showing a state in which the processing table and the drive mechanism are connected); FIG. 2 is a plan view (sectional view taken along line VIII-VIII in FIG. 1) showing a state in which an elevating floor on which a processing table is installed is located near the floor surface. FIG. 3 is a sectional view showing the pedestal when the elevating floor on which the processing table is installed is located near the floor surface. 1 is a block diagram showing the configuration of a control system of a heat treatment furnace according to an example. 5 is a flowchart illustrating an example of a process for detecting a deviation from a reference mounting state of a workpiece.

The main features of the embodiment described below will be listed. The technical elements described below are independent technical elements that exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims as filed. do not have.

In the batch heat treatment furnace disclosed herein, the processing table has a circular shape when viewed from above, and is configured to be rotatable around a first axis extending vertically through the center of the processing table. a first rotary table; and at least one rotary table, which is arranged inside the first rotary table when viewed from above and is configured to be rotatable around a second axis extending vertically through the center of the first rotary table. 2 rotary tables. When viewed in plan, the center position of the second rotary table may be at a different position from the center position of the first rotary table. The drive device may include a first drive section that rotationally drives the first rotary table, and a second drive section that rotationally drives the second rotary table. The sensor is configured to rotate the second rotation table when the elevating floor is located at the first position, the first drive unit rotates the first rotary table, and the second drive unit rotates the second rotary table. It is also possible to detect the displacement of the workpiece placed on the table. According to such a configuration, since the processing table includes the first rotary table and the second rotary table, the workpiece revolves during heat treatment (around the first axis as the first rotary table rotates). (rotates around the second axis as the second rotary table rotates) and rotates on its own axis (rotates around the second axis along with the rotation of the second rotary table), and the workpiece placed on the second rotary table can be uniformly heat-treated. Further, the sensor detects the object to be processed placed on the second rotary table when the elevating floor is located at the first position and the first rotary table and the second rotary table are rotated. Detect deviation. Therefore, by rotating the first rotary table and the second rotary table during the heat treatment, it is possible to detect in advance whether or not the object to be treated will come into contact with the furnace body.

In the batch heat treatment furnace disclosed in this specification, a plurality of objects to be processed may be stacked vertically and placed on the processing table. According to such a configuration, many objects to be processed can be heat-treated at one time. On the other hand, when a plurality of objects to be processed are piled up in the vertical direction, there is a high possibility that the objects to be processed will be displaced. Since the displacement of the objects to be processed is detected by the sensor, the displacement of the objects to be processed can be detected in advance even if the objects to be processed are stacked one on top of the other and are likely to deviate from the reference mounting state.

In the batch heat treatment furnace disclosed in this specification, the sensor is arranged to detect that the workpiece is displaced from a predetermined position toward the outer periphery of the processing table when the processing table is viewed from above. Good too. According to such a configuration, it is possible to prevent the object to be processed from collapsing toward the outer periphery of the processing table due to rotation of the processing table.

In the batch heat treatment furnace disclosed in this specification, the sensor may be arranged to detect a shift of the object to be processed in a predetermined range in the height direction. According to such a configuration, it is possible to detect displacement of the object to be processed over a predetermined range in the height direction. Therefore, the displacement of the object to be processed can be detected more reliably.

A heat treatment furnace 10 according to this embodiment will be described with reference to the drawings. The heat treatment furnace 10 is a batch type heat treatment furnace, and is used to heat treat the object W to be treated. As shown in FIGS. 1 and 2, the heat treatment furnace 10 includes a pedestal 16, a furnace body 11, and a processing table 30.

The pedestal 16 is located below the furnace body 11 and supports the furnace body 11. By supporting the furnace body 11 with the pedestal 16, a work space is formed below the furnace body 11 in which the processing table 30 is attached and detached. The pedestal 16 is made up of a plurality of frame members, and an upper frame is formed at the upper end of the four frame members (see FIG. 8). A sensor 40 (shown in FIGS. 8 to 10) is installed in the upper frame. Note that the sensor 40 will be explained in detail later.

As shown in FIGS. 1 and 2, the furnace body 11 is made of refractory material and includes a cylindrical side wall 14 and a disk-shaped ceiling wall 12. The lower end of the side wall 14 is fixed to the frame 16, and the upper end extends to the ceiling wall 12. The ceiling wall 12 contacts the upper end of the side wall 14 and closes the opening at the upper end of the side wall 14. An exhaust port (not shown) is formed in the center of the ceiling wall 12.

The furnace body 11 further includes an elevating floor 18. The elevating floor 18 is formed in a rectangular box shape when viewed from above, and a driving device (20, 22) for rotationally driving the processing table 30 is housed inside the elevating floor 18. The drive device (20, 22) includes a drive source 22 and a drive mechanism 20. The drive source 22 is a general-purpose motor (that is, a motor without a servo function) for rotationally driving the processing table 30. The driving force generated by the drive source 22 is transmitted to the processing table 30 (specifically, each of the main hearth 34 and the auxiliary hearth 36) via the drive mechanism 20.

As shown in FIGS. 4 to 7, the processing table 30 includes a main hearth 34 and four auxiliary hearths 36 installed on the main hearth 34. The main hearth 34 has a small diameter part 33 located at the upper end and a large diameter part 32 located below the small diameter part 33. The small diameter portion 33 and the large diameter portion 32 have a disc-shaped outer shape and are integrated so that their central axes are located on the same straight line. A recess 34a that can be engaged with the drive mechanism 20 is formed at the center of the lower surface of the large diameter portion 32. When the processing table 30 is attached to the elevating floor 18, the main hearth 34 (the small diameter portion 33 and the large diameter portion 32) moves along its central axis (i.e., vertically through the center of the small diameter portion 33 and the large diameter portion 32). The extending line) coincides with the axis of the furnace body 11.

The auxiliary hearth 36 has a disc-like shape and is rotatably installed with respect to the main hearth 34 . Specifically, a through hole is formed in the main hearth 34 from its upper end surface (small diameter portion 33) to its lower end surface (large diameter portion 32), and the auxiliary hearth 36 is formed in the through hole. is arranged so that it can rotate. That is, each of the auxiliary hearths 36 is rotatable around its axis (that is, a line extending vertically through the center of the auxiliary hearth 36). In this embodiment, the four sub-hearths 36 are installed at equal intervals in the circumferential direction (that is, the four sub-hearths 36 are installed at 90° intervals in the circumferential direction). Each of the four auxiliary hearths 36 has an engagement surface 36a at its lower end that can be engaged with a drive mechanism 20, which will be described later (see FIGS. 6 and 7). Each of the axes of the four auxiliary hearths 36 is parallel to the axis of the main hearth 34 and arranged at an equal distance from the axis of the main hearth 34 . The upper surface of the main hearth 34 and the upper surface of the auxiliary hearth 36 are flush with each other, and the workpiece W can be placed on the upper surface of the auxiliary hearth 36.

The rotation direction and rotation speed of each of the main hearth 34 and the auxiliary hearth 36 can be changed and stopped. Since the object W to be processed is placed on the upper surface of the auxiliary hearth 36, the object W to be processed rotates as the main hearth 34 rotates, and the object W to be processed rotates as the auxiliary hearth 36 rotates. It will do what is called rotation. The rotation direction of each hearth 34, 36 can be set arbitrarily. For example, as shown in FIG. 3, both the main hearth 34 and the auxiliary hearth 36 may rotate counterclockwise, or the main hearth 34 and the auxiliary hearth 36 may both rotate clockwise. . Alternatively, the main hearth 34 may rotate clockwise while the secondary hearth 36 rotates counterclockwise, or the main hearth 34 rotates counterclockwise while the secondary hearth 36 rotates clockwise. It may be rotated. By appropriately controlling the rotational speed and direction of the main hearth 34 and the sub-hearth 36, the workpiece W placed on the sub-hearth 36 can be heated uniformly.

As shown in FIGS. 6 and 7, the drive mechanism 20 includes a first connecting portion 46 connected to the recess 34a of the main hearth 34 and a second connecting portion 44 connected to the lower surface of the auxiliary hearth 36. ing. The rotational driving force of the drive source 22 is transmitted to the first connecting portion 46 via a transmission member (such as a chain) not shown. A disk-shaped support plate 48 is fixed to the lower end of the first connecting portion 46 . The support plate 48 comes into contact with the lower surface of the main hearth 34 and supports the main hearth 34 . A second drive shaft 42 is fixed to the lower surface of the second connecting portion 44 . The second drive shaft 42 passes through an unillustrated through hole of the support plate 48, and the rotational driving force of the drive source 22 is transmitted to the lower end of the second drive shaft 42 via an unillustrated transmission member (such as a chain). By transmitting the rotational driving force of the drive source 22 to each of the first connecting portion 46 and the second connecting portion 44, the main hearth 34 rotates (rotates), and the auxiliary hearth 36 rotates and revolves accordingly. I will do it.

The recess 34a of the processing table 30 (main hearth 34) is connected to the first connection part 46, and the engagement surface 36a of the processing table 30 (secondary hearth 36) is connected to the second connection part 44, so that A processing table 30 is attached to the drive mechanism 20. As a result, the processing table 30 is placed on the upper surface of the support plate 48 of the drive mechanism 20, and the processing table 30 is supported by the drive mechanism 20. When the processing table 30 is attached to the drive mechanism 20, the processing table 30 is supported above the elevating floor 18, as shown in FIGS. 1 and 2. Here, the elevating floor 18 is moved between a position near the lower end of the furnace body 11 (an example of a second position in the claims) and a position near the floor surface (an example of the second position in the claims) by an elevating device 24 provided on the pedestal 16. (an example of the first position). When the elevating floor 18 is positioned near the floor surface, the lower end of the side wall 14 is opened and the processing table 30 can be attached to and detached from the drive mechanism 20 (the state shown in FIG. 1).

Further, when the elevating floor 18 is positioned near the lower end of the furnace body 11 with the processing table 30 attached to the drive mechanism 20, the processing table 30 closes the lower end opening of the side wall 14 (as shown in FIG. situation). When the processing table 30 closes the lower end opening of the side wall 14, the processing table 30 and the furnace body 11 form a furnace space 26 in which the workpiece W is heat-treated. As shown in FIGS. 2 and 3, the upper surface of the main hearth 34 and the upper surface of the auxiliary hearth 36 are exposed in the furnace space 26, and the workpiece W placed on the upper surface of the auxiliary hearth 36 is exposed. It is accommodated in the furnace space 26. Note that a heater 50 (not shown in FIG. 10) and a gas supply device 52 (not shown in FIG. 10) are provided in the furnace space 26. The workpiece W is heated by the heater 50, and the atmosphere in the furnace space 26 is controlled by the gas supply device 52.

The work of placing the workpiece W on the upper surface of the processing table 30 (specifically, the auxiliary hearth 36) is performed by an operator. Specifically, the processing table 30 is taken out of the heat treatment furnace 10, and the operator places the workpiece W on the upper surface of the sub-hearth 36 of the processing table 30 outside the heat treatment furnace 10. Examples of the object to be processed W include laminated ceramic parts such as ceramic capacitors, ceramic piezoelectric elements, and ceramic resistors. The object W to be processed is placed on a flat setter and placed on the upper surface of the sub-hearth 36 . The setters are configured so that they can be stacked vertically. Hereinafter, in this embodiment, the entirety of the parts to be heat treated and the setter on which the parts to be heat treated are placed will be referred to as "workpiece W". The objects W to be processed are stacked vertically and placed on the upper surface of the sub-hearth 36 . Thereby, many objects W to be processed can be heat-treated at once. The processing table 30 on which the workpiece W is placed on the upper surface of the auxiliary hearth 36 is transported to a predetermined position within the pedestal 16 using a transport vehicle (not shown) and connected to the drive mechanism 20 .

Here, the sensor 40 installed on the pedestal 16 will be explained. The objects W to be processed are stacked vertically on the upper surface of the auxiliary hearth 36 by an operator, so when stacking another object W on top of one object W, the objects W to be processed are stacked on top of each other. The workpiece W may be placed offset from the workpiece W below. Then, the axes of the plurality of workpieces W in a state of being stacked with deviations are relative to the axis of a state in which the plurality of workpieces W are accurately stacked in the vertical direction (hereinafter also referred to as the reference mounting state). It may shift. If the elevating floor 18 is raised in a state where the plurality of objects W stacked vertically are shifted, there is a possibility that the objects W to be processed will come into contact with the furnace body 11 . Further, even if the plurality of processing objects W stacked in the vertical direction do not come out of place to the extent that they come into contact with the furnace body 11 when the elevating floor 18 is raised, the plurality of processing objects W stacked in the vertical direction If heat treatment is performed in the heat treatment furnace 10 with W slightly deviated, when the main hearth 34 and the auxiliary hearth 36 rotate during heat treatment, the misalignment of the axes of the stacked workpieces W will increase. There is. Then, during the heat treatment, there is a possibility that the plurality of objects W to be processed that are stacked in the vertical direction may collapse and come into contact with the inner wall surface of the furnace body 11. If the deviation between the plurality of workpieces W stacked in the vertical direction is large, the operator can visually recognize it, but if the deviation is slight, the operator cannot visually recognize it. difficult. Therefore, the sensor 40 is used to detect the deviation of the workpiece W from the reference mounting state.

As shown in FIGS. 8 and 9, the sensor 40 is attached to a plate hanging from the upper frame of the pedestal 16. As shown in FIGS. The sensor 40 is an optical sensor including a light emitting part and a light receiving part, and is installed so as to be able to detect the deviation of the workpiece W from the reference mounting state. Specifically, the sensor 40 is installed to detect the workpiece W located outside the outer periphery of the small diameter portion 33 . That is, as shown in FIG. 8, the optical path of the sensor 40 is set to substantially coincide with the tangent to the outer circumference of the small diameter portion 33 when the processing table 30 is viewed from above, and whether the object W to be processed blocks the optical path or not. Detect whether or not. The sensor 40 is installed so that its optical path is parallel to the side surface of the upper frame of the pedestal 16. In this embodiment, four sensors 40 are installed, and when the processing table 30 is viewed from above, one sensor 40 having an optical path parallel to the optical path of one sensor 40 is arranged, and one sensor 40 is arranged orthogonal to the optical path of one sensor 40. Two sensors 40 with optical paths are arranged.

Further, as shown in FIG. 9, the sensor 40 is installed so that its optical path is oblique when the processing table 30 is viewed from the side. Specifically, the sensor 40 (specifically, the light emitting part of the sensor 40) is installed near the upper end of the inner wall surface of the plate hanging from the upper frame of the pedestal 16 (at a position close to the furnace body 11). The light emitting unit outputs light toward a position lower than the installed position and lower than the upper end of the workpiece W placed on the processing table 30. The light receiving section of the sensor 40 is installed on the optical axis of the light emitting section of the sensor 40. Therefore, the light receiving part of the sensor 40 is installed at a position lower than the upper end of the workpiece W placed on the processing table 30. By installing the sensor 40 in this manner, the sensor 40 can have a wide detectable range in the height direction. Note that the angle of the light output from the sensor 40 when the processing table 30 is viewed from the side is not particularly limited. For example, the sensor 40 may output light from near the upper end of the inner wall surface of the pedestal 16 toward near the lower end. Furthermore, if the object W to be processed can be detected (that is, if the optical path of the sensor 40 passes through a position lower than the upper end of the object W to be processed), the sensor 40 may output light substantially horizontally. Further, in this embodiment, the sensor 40 is fixed to the pedestal 16, but the configuration is not limited to this. For example, the sensor may be installed movably, and the position of the sensor may be changed depending on the placement state of the workpiece W (for example, the height of a plurality of workpieces W stacked in the vertical direction). It may be configured so that it can be done. Further, the sensor is not limited to an optical sensor, and the type of sensor is not particularly limited as long as it can detect whether or not the workpiece W is located outside the outer periphery of the small diameter portion 33. .

As shown in FIG. 10, the heat treatment furnace 10 further includes a control section 54. The control unit 54 is configured by, for example, a computer including a CPU, ROM, and RAM. The control unit 54 is connected to the sensor 40, and receives a detection signal from the sensor 40. The control unit 54 controls the operation of each part of the heat treatment furnace 10 based on input instructions and detection signals. That is, the control unit 54 raises and lowers the elevator floor 18 by controlling the elevator device 24, controls the rotation of the processing table 30 by controlling the drive devices (20, 22), and controls the heater 50 and the gas supply device 52. The temperature and atmosphere inside the furnace are controlled by controlling the temperature and atmosphere inside the furnace.

Next, a process for detecting a deviation of the workpiece W from the reference mounting state will be described. When a plurality of objects W to be processed are stacked vertically on the processing table 30 (specifically, the sub-hearth 36) by an operator, the processing table 30 on which the objects W to be processed are placed can be moved up and down. It is installed on the floor 18. When the processing table 30 on which the workpiece W is placed is installed on the elevating floor 18, the control unit 54 controls the drive devices (20, 22) to move the main hearth 34 and The sub-hearth 36 is rotated (S12). That is, before raising the elevating floor 18 and moving the workpiece W on the processing table 30 into the furnace body 11, the control unit 54 controls the main hearth 34 and the auxiliary furnace in the work space provided on the pedestal 16. Rotate the floor 36. In the process of detecting the deviation of the workpiece W from the standard mounting state, the control unit 54 rotates the main hearth 34 and the sub-hearth 36 until the main hearth 34 rotates once.

Next, the control unit 54 determines whether or not the object W to be processed is detected by the sensor 40 while the main hearth 34 and the auxiliary hearth 36 are rotating (S14). The sensor 40 is installed to detect the workpiece W located outside the outer periphery of the small diameter portion 33 . As described above, if the plurality of objects to be processed W stacked in the vertical direction are misaligned, the misalignment becomes large due to the rotation of the main hearth 34 and the sub-hearth 36. Further, if a plurality of objects W stacked in the vertical direction are shifted toward the center of the processing table 30 when placed on the sub-hearth 36, the shifted objects W are The rotation of the hearth 34 and the auxiliary hearth 36 causes them to protrude toward the outside of the processing table 30 . Therefore, when the plurality of objects W stacked in the vertical direction are misaligned, by rotating the main hearth 34 and the sub-hearth 36, the light emitted from the light emitting part of the sensor 40 can be transferred to the light receiving part. Since this cannot be detected, the inclination of the object W to be processed can be detected depending on whether or not the light is detected by the light receiving section.

When the sensor 40 detects the workpiece W (YES in step S14), the control unit 54 determines that the plurality of workpieces W stacked in the vertical direction are misaligned. Then, the control unit 54 notifies the operator that the plurality of workpieces W stacked in the vertical direction are misaligned (S16). The notification method is not particularly limited; for example, the control unit 54 may notify the operator by displaying a notification to that effect on an interface device (not shown) for operating the heat treatment furnace 10. , the abnormality may be notified by a notification means (not shown) such as a buzzer or a lamp.

On the other hand, if the sensor 40 does not detect the workpiece W until the main hearth 34 rotates once (NO in step S14), the control unit 54 controls the It is determined that W is not shifted. Then, the process of detecting the deviation of the workpiece W from the reference mounting state is completed.

In this embodiment, before the elevating floor 18 is raised and the workpiece W on the processing table 30 is moved into the furnace body 11, a deviation of the workpiece W from the standard mounting state is detected. Therefore, the displacement of the workpiece W can be detected before the workpiece W is placed in the furnace body 11. Further, the process of detecting the deviation of the workpiece W from the standard mounting state is performed while rotating the main hearth 34 and the sub-hearth 36. Therefore, it is possible to detect whether or not the object to be processed W has deviated from the reference mounting state over the entire circumference of the object to be processed. If the workpiece W is deviated from the reference mounting state, the deviation may become larger by rotating the processing table 30 during the heat treatment. Since a slight deviation of the workpiece W from the reference mounting state can be detected in advance, it is possible to avoid the workpiece W collapsing during the heat treatment.

In this embodiment, in the process of detecting the deviation of the workpiece W from the reference mounting state, it is determined whether the sensor 40 detects the workpiece W before the main hearth 34 rotates once. was detected, but the configuration is not limited to this. The sensor 40 may detect whether or not the object to be processed W is detected while the main hearth 34 rotates more than once (for example, while the main hearth 34 rotates twice). It is detected whether the sensor 40 detects the object W to be processed while the bed 34 rotates less than one rotation (for example, while the main hearth 34 rotates 180 degrees or 90 degrees, etc.). Good too. Further, in this embodiment, four sensors 40 are installed in the pedestal 16, but the configuration is not limited to this. The number of sensors 40 installed in the frame 16 may be less than four or more than four.

Although specific examples of the technology disclosed in this specification have been described above in detail, these are merely illustrative and do not limit the scope of the claims. The techniques described in the claims include various modifications and changes to the specific examples illustrated above. Further, the technical elements described in this specification or the drawings exhibit technical usefulness singly or in various combinations, and are not limited to the combinations described in the claims as filed.

W Workpiece 10 Heat treatment furnace 11 Furnace body 12 Ceiling wall 14 Side wall 16 Frame 18 Elevating floor 20 Drive mechanism 22 Drive device 24 Elevating device 26 Furnace space 28 Opening 30 Processing table 32 Large diameter portion 33 Small diameter portion 34 Main hearth 36 Secondary hearth 40 Sensor 42 Second drive shaft 44 Second connection section 46 First connection section 48 Support plate 50 Heater 52 Gas supply device 54 Control section

Claims (4)

A furnace body including a ceiling wall, a side wall, and an elevating floor;
a processing table that is rotatably arranged with respect to the elevating floor and on which a workpiece can be placed;
a drive device that is provided on the elevating floor and rotationally drives the processing table;
a sensor that detects a deviation from a reference placement state of the object to be processed placed on the processing table;
The elevating floor is movable between a first position where the lower end of the side wall is open and a second position where the lower end of the side wall is closed.
When the elevating floor is located at the second position, the top surface of the processing table is exposed in the furnace body,
The sensor is arranged to detect a shift of the object to be processed placed on the processing table when the elevating floor is located at the first position,
In the batch type heat treatment furnace, the sensor detects a shift of the object to be processed when the elevating floor is located at the first position and the drive device rotates the processing table. The processing table is
a first rotary table that has a circular shape when viewed from above and is configured to be rotatable around a first axis extending vertically through the center;
at least one second rotary table that is arranged inside the first rotary table when viewed in plan and configured to be rotatable around a second axis that extends vertically through the center thereof; It is equipped with
When viewed in plan, the center position of the second rotary table is at a different position from the center position of the first rotary table,
The drive device includes a first drive unit that rotationally drives the first rotary table, and a second drive unit that rotationally drives the second rotary table,
The sensor is configured such that the elevating floor is located at the first position, and the first drive unit rotates the first rotary table and the second drive unit rotates the second rotary table. 2. The batch heat treatment furnace according to claim 1, wherein displacement of the object to be processed placed on the second rotary table is detected in this state. 3. The sensor according to claim 1 , wherein the sensor is arranged to detect that the object to be processed is shifted from a predetermined position toward the outer circumference of the processing table when the processing table is viewed from above. Batch type heat treatment furnace. The batch heat treatment furnace according to any one of claims 1 to 3 , wherein the sensor is arranged to detect a shift of the workpiece in a predetermined range in the height direction.

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