JP7371406B2 - Continuous heat treatment furnace extraction system and workpiece extraction method - Google Patents

Description

The present invention relates to an extraction system for extracting a workpiece out of the furnace in a continuous heat treatment furnace equipped with a conveyor for transporting the workpiece into the furnace, and a method for extracting the workpiece using the extraction system.

For example, in a continuous heat treatment furnace equipped with a conveyor for transporting workpieces into the furnace, the workpieces may be heat-treated by lining them up in multiple rows on the conveyor. As a workpiece extraction device in such a case, there is known a device in which a detection rod corresponding to each row of the workpieces is suspended from the furnace ceiling into the furnace (see Patent Document 1 below). In the device described in this cited document 1, a workpiece conveyed by a conveyor hits the lower end of a detection rod, and the workpiece is detected by swinging the detection rod. When a workpiece is detected, the detection rod is raised to secure a path for extracting the workpiece, and then a robot arm is used to grasp the workpiece and extract it out of the furnace.

However, in the device described in Cited Document 1, since the detection rod and the workpiece repeatedly come into contact in a high-temperature environment, the detection rod may bend over time, which may lead to misgrip of the workpiece. Furthermore, in order for the robot arm to grasp the workpiece after detecting the workpiece, it is necessary to wait until the detection rod has finished rising and the extraction path has been secured, making it difficult to increase the productivity of the extraction work.

Japanese Patent Application Publication No. 2008-292008

With the above circumstances as a background, the present invention is capable of non-contact detection of workpieces arranged in multiple rows on a conveyor, and is capable of increasing the productivity of extraction work in a continuous heat treatment furnace. The purpose of this invention is to provide an extraction system and a work extraction method.

The extraction system of the present invention is an extraction system for extracting workpieces arranged in a plurality of rows parallel to the conveyance direction on the conveyor of a continuous heat treatment furnace,
A laser beam is provided at a position facing each row of the workpieces on the downstream side of the conveyance direction outside the furnace body, and irradiates the workpiece located at the head of each row with a laser beam to measure the distance to the workpiece at the head. a detection means for detecting;
an extraction robot that has a gripping part at the tip of a movable arm and grips the workpiece on the conveyor and extracts it out of the furnace using distance information of each row sent out from the detection means;
It is characterized by having the following.

According to the extraction system of the present invention configured in this way, it is possible to detect workpieces arranged in multiple rows on the conveyor without contact and obtain distance information for each row, so it is possible to detect the workpieces arranged in multiple rows on the conveyor and obtain distance information for each row. This eliminates the need for workpiece misgrip caused by the detection rod and the problem of waiting for extraction until the detection rod has finished rising, thereby increasing the productivity of extraction work.

Further, in the present invention, the detection is performed so that the laser beam is irradiated into the furnace using an extraction opening formed in the furnace wall through which the movable arm is inserted when extracting the workpiece out of the furnace. Means can be arranged. In this case, the detection means can be arranged so that the laser beam passes through a region below the movable arm insertion region of the extraction opening.
In this way, there is no need to separately provide an opening in the furnace wall through which the laser beam passes, and the opening can be shared with the extraction opening through which the movable arm is inserted.

In the extraction system of the present invention, a heat shield plate having a through hole through which the laser beam passes can be provided between the detection means and the workpiece, and an inner surface of the through hole can be processed to be black. .
The detection means disposed facing the workpiece is easily exposed to heat from the heat treatment furnace. In order to protect the detection means, it is effective to provide a heat shield plate between the detection means and the workpiece. In this case, it is necessary to form a through hole in the heat shield plate to allow the laser beam to pass through, but a portion of the laser beam passing through the through hole is reflected on the inner surface of the through hole and becomes stray light, which is transmitted to the detection means. There is a risk that the light will be received and false detection will occur. As a means to solve this problem, it is effective to blacken the inner surface of the through hole. Stray light is easily absorbed by the black surface, and erroneous detection by the detection means can be suppressed.

Here, in the present invention, a hood may be provided to cover three sides of the detection means other than the front where the heat shield plate is provided, and an air supply path may be provided for supplying high-pressure air to the space within the hood.
By supplying high-pressure air to the space within the hood where the detection means is provided, it is possible to prevent dust from entering the hood and to prevent the detection means from becoming hot.

Further, in the present invention, the focal position of the laser beam irradiated toward the workpiece can be set at a position between the heat shield plate and the workpiece.
If the diameter of the laser beam that hits the workpiece is too small, distance detection tends to vary depending on the shape of the workpiece that is hit by the laser beam. For this reason, it is desirable to set the focal point of the laser beam in front of the workpiece to widen the diameter of the laser beam hitting the workpiece to some extent. On the other hand, if the focal point position is brought too close to the detection means, stray light is likely to occur at the heat shield plate. For this reason, it is desirable that the focal position of the laser beam be set between the heat shield plate and the workpiece.

The workpiece extraction method of the present invention is a method for extracting workpieces arranged in a plurality of rows parallel to the conveyance direction on a conveyor of a continuous heat treatment furnace, the method comprising:
A detecting means is provided at a position facing each row of the workpieces on the downstream side of the conveyor outside the furnace body, and a gripping section is provided at the tip of the movable arm to grip the workpieces on the conveyor and remove the workpieces from the furnace. Equipped with an extraction robot that extracts into
irradiating the workpiece located at the head of each row with a laser beam from the detection means to detect the distance to the workpiece at the head;
identifying a column located at the shortest distance from the extraction side end of the conveyor as an extraction target column using distance information of each column sent from the detection means;
a step of gripping a workpiece located at the head of the extraction target row by the extraction robot and extracting it out of the furnace;
It is characterized by having the following.

According to the workpiece extraction method configured in this way, similarly to the invention of the extraction system described above, it is possible to detect the workpieces arranged in multiple rows on the conveyor without contact and obtain distance information for each row. This eliminates the need for the conventional detection rod that comes into contact with the detection rod, which eliminates problems such as misgripping of the workpiece caused by the detection rod and waiting for extraction until the detection rod has finished rising, increasing the productivity of extraction work.

1 is a diagram showing the overall configuration of a continuous heat treatment furnace equipped with an extraction system according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of a state in which workpieces are placed on a conveyor in a charging section of the continuous heat treatment furnace shown in FIG. 1; FIG. 2 is a plan view showing the extraction section and the surrounding area of the continuous heat treatment furnace of FIG. 1. FIG. FIG. 2 is a side view showing the extraction section and the surrounding area of the continuous heat treatment furnace of FIG. 1. FIG. FIG. 5 is an enlarged view of the laser sensor of FIG. 4 and its surrounding area. FIG. 3 is a diagram schematically showing a focal position of a laser beam irradiated toward a workpiece W. FIG. It is an explanatory diagram about extraction operation of an extraction system. It is a flowchart of the extraction operation of the extraction system.

Next, embodiments of the present invention will be described in detail based on the drawings.
FIG. 1 shows the overall configuration of a continuous heat treatment furnace equipped with an extraction system, which is an embodiment of the present invention. In FIG. 1, 10 is a continuous heat treatment furnace, and W is a ring-shaped workpiece as an object to be treated. The interior of the continuous heat treatment furnace 10 is divided into a charging section 12, a heat treatment section 14, and an extraction section 16, and the heat treatment section 14 is provided with a heater 15 for heating.
Further, a conveyor 20 for transporting the workpiece W is provided in the furnace, extending over the charging section 12, the heat treatment section 14, and the extraction section 16. Conveyor 20 includes end rollers 21, 22 and support rollers 23.

A charging opening 17 and an extraction opening 18 are formed in the furnace walls on the charging side (upstream side in the transport direction) and the extraction side (downstream side in the transport direction) of the continuous heat treatment furnace 10, respectively. The work W charged through the charging opening 17 is heat treated (for example, normalized) in the heat treatment section 14, and after the predetermined heat treatment is completed, it is extracted out of the furnace through the extraction opening 18.

A charging robot 30 serving as a charging means is arranged outside the furnace body 11 and on the upstream side in the transport direction. The charging robot 30 has a base 32 and a movable arm 34 extending therefrom. The movable arm 34 has a plurality of joints that rotate or bend, and a grip portion 36 for gripping the workpiece W is attached to the tip of the movable arm 34 . The gripping part 36 has a plurality of claws that are movable in the diameter expansion direction or diameter reduction direction, and the diameter-reduced claws are inserted into the holes of the workpiece W, and the claws are expanded to grasp the inner circumference of the workpiece W. The workpiece W is gripped by pressing against the surface. Note that the method of gripping the workpiece W is not limited to this, and it is also possible to grip the workpiece W by gripping the outer peripheral surface of the workpiece W with claws, for example.

The charging robot 30 grasps the workpiece W supplied by the external conveyor 39 and places it on the conveyor 20 moving at a predetermined speed inside the furnace (charging section 12) through the charging opening 17. . In this example, as shown in FIG. 2, the workpieces W are arranged in nine rows (2A to 2I) in the width direction of the conveyor 20, and the workpieces W constituting each row are arranged in the conveyance direction of the conveyor 20. arranged along parallel lines. The works lined up on the conveyor 20 are sequentially conveyed to the left in the figure, are heat treated in the heat treatment section 14, and then moved to the extraction section 16 on the left side in the figure.

As shown in FIGS. 3 and 4, on the extraction unit 16 side of the continuous heat treatment furnace 10, there are a plurality of laser sensors 40 as detection means, an extraction robot 60 as extraction means, these laser sensors 40 and extraction A control section 70 connected to the robot 60 is provided. The extraction system 75 of this embodiment includes the laser sensor 40, the extraction robot 60, and the control section 70.

As shown in FIGS. 3 and 4, the laser sensor 40 is provided outside the furnace body 11 and on the downstream side in the conveyance direction, at a position facing each row of workpieces W 2A to 2I.
The laser sensor 40 detects the distance to the workpiece W, which is the object to be measured, using the TOF (Time of Flight) method, and intermittently irradiates the workpiece W with a laser beam. The distance to the workpiece W is detected based on the time from when the laser beam (reflected light) reflected on the surface of the workpiece W is detected.
The laser sensor 40 includes a light projecting part that irradiates the inside with a laser beam (not shown), a light receiving part that receives return light (reflected light) reflected from the workpiece W, and a distance to the workpiece W. A distance measurement section that outputs an electrical signal corresponding to the measured distance is provided.

As shown in FIG. 4, the laser sensor 40 configured in this manner is attached and fixed via a bracket 42 to a dedicated fixed pedestal 41 that is provided separately and apart from the furnace body 11. By using the dedicated fixed frame 41, vibrations of the conveyor 20 and effects of thermal expansion of the furnace body can be suppressed. Note that, as shown in FIG. 3, the fixed pedestal 41 includes a mounting surface 41a extending in a direction perpendicular to the conveyance direction (furnace width direction), and a plurality of (nine in this example) mounting surfaces 41a are mounted on the mounting surface 41a. Laser sensors 40 are installed side by side.

The laser sensor 40 is adjusted to a height on the mounting surface 41a such that the laser beam is irradiated horizontally toward the workpiece W. As shown in FIG. 4, an extraction aperture 18 is provided in the irradiation direction of the laser sensor 40, and the laser light travels into the furnace through the extraction aperture 18 and reaches the side surface of the target workpiece W. The laser light reflected from the side surface of the workpiece W travels out of the furnace through the extraction opening 18 and reaches the light receiving section of the laser sensor 40. More specifically, the region above the extraction opening 18 is a movable arm insertion region used by the movable arm 34 of the extraction robot 60, which will be described later, and the laser beam penetrates the region below the movable arm insertion region of the extraction opening 18. pass.

Here, in order to prevent the heat emitted outward from the extraction aperture 18 from affecting the laser sensor 40 disposed near the extraction aperture 18 in this example, as shown in FIG. A heat shield plate 44 is provided in front of the sensor 40 and between the laser sensor 40 and the workpiece W. The heat shield plate 44 is composed of a metal thin plate 44a and a heat insulating material 44b, and the lower end of the metal thin plate 44a extending downward is supported and fixed by a rod-shaped member 46 extending horizontally from the fixed frame 41. has been done.

In addition, a cover 48 having a substantially L-shaped cross section is provided above and behind the laser sensor 40 (on the side opposite to the heat shield plate 44). A hood is formed to cover three sides (upper, rear, and lower) of the laser sensor 40 where the laser sensor 40 is not present. A pipe body forming an air supply path 43 connected to a high-pressure air source (not shown) is attached to the upper part of the fixed frame 41, and high pressure is supplied from the tip 43a of the air supply path 43 to the space inside the hood. By supplying air, measures against dust and heat of the laser sensor 40 are taken.

As shown in the partially enlarged view of FIG. 5, the heat shield plate 44 is formed with a through hole 45 through which the laser beam passes, and the inner surface of the through hole 45 is processed in black. The black coloring can be achieved, for example, by applying black paint to the inner surface of the through hole 45. By processing the inner surface of the through hole 45 in black, stray light is easily absorbed by the black surface, and erroneous detection by the laser sensor 40 can be suppressed. In this example, as shown by the dotted line in the partially enlarged view, the inner surface of the through hole 45 of the heat shield plate 44 and the surface facing the light emitting/receiving surface of the laser sensor 40 are processed in black.

Further, in this example, as shown in the schematic diagram of FIG. 6, the focal position 51 of the laser beam irradiated toward the workpiece W is set at a position between the heat shield plate 44 and the workpiece W. In other words, the focal position of the laser beam is the position where the beam diameter of the laser beam is the smallest.
If the diameter of the laser beam that hits the workpiece W is too small, variations in distance detection tend to occur depending on the shape of the workpiece that is hit by the laser beam. For this reason, it is desirable to set the focal point 51 of the laser beam in front of the workpiece W so that the diameter of the laser beam hitting the workpiece W is increased to some extent. On the other hand, if the focal point position is brought too close to the laser sensor 40, stray light is likely to occur at the heat shield plate 44. Therefore, in this example, the focal position 51 of the laser beam is set at a position between the heat shield plate 44 and the workpiece W.

Next, the control unit 70 (see FIG. 4) is connected to the laser sensor 40 and the extraction robot 60. The control unit 70 stores the distance information for each column sent from the laser sensor 40, and specifies the column located at the shortest distance (the shortest distance from the extraction side end 20a of the conveyor 20) as the extraction target column. , transmits its column number and its distance information to the extraction robot 60. The control unit 70 can be configured by a computer including a CPU, RAM, ROM, storage unit, and the like. Further, the control section 70 can also be configured as a part of the control section of the extraction robot 60.

The extraction robot 60 grasps the workpiece W on the conveyor 20 and extracts it out of the furnace. The basic configuration of the extraction robot 60 is the same as that of the charging robot 30. Components that are common to the configuration of the charging robot 30 are indicated using the same reference numerals, and the explanation thereof will be omitted. The extraction robot 60 uses the row number and distance information of the extraction target row sent from the control unit 70 and information on the conveyor speed to synchronize the timing at which the work W in the extraction target row reaches the scheduled extraction point. Then, insert the gripping part 36 at the tip of the movable arm 34 into the furnace through the extraction opening 18, spread the claws to grip the workpiece W, and extract it outside the furnace (more specifically, onto the outside table 65 shown in FIG. 1). do.

Next, a series of extraction operations will be explained using FIGS. 7 and 8. Here, as shown in FIG. 7(A), the following explanation will be given using as an example a case where all nine rows of workpieces W have reached the heat treatment completion line P1 and can be detected by the laser sensor 40.
First, as shown in FIG. 7A, the laser sensor 40 arranged corresponding to each row 2A to 2I intermittently irradiates laser light and performs a detection operation on the approaching workpiece W (step S001). The distance information of each column detected by the laser sensor 40 is transmitted to the control section 70 and stored in the storage section of the control section 70 (step S002).

Next, the control unit 70 compares the stored distance information of each column and specifies the column (2A in this case) having the shortest distance from the extraction side end 20a of the conveyor 20 as the extraction target column (step S003). Then, the control unit 70 transmits the column number (here, 2A) and its distance information to the extraction robot 60 as information on the extraction target column (step S004).

The extraction robot 60 uses the row number and its distance information sent from the control section 70 and the information on the conveyor speed to determine the relative positional relationship between the gripping section 36 and the workpiece W at the head of the extraction target row 2A. recognize. Based on this relative positional relationship, the extraction robot 60 grips the workpiece W at the timing when the first workpiece W in the extraction target row 2A reaches the scheduled extraction point P2, as shown in FIG. 7(B), and The operation of extracting to the outside is executed (step S005).

After the operation of extracting the workpieces W in the extraction target column 2A to the outside of the furnace is completed (see FIG. 7(C)), by repeatedly performing steps S001 to S005, the workpieces W located in columns 2B to 2I are also sequentially extracted. Extracted outside the furnace.

Note that the workpiece W to be extracted and the surrounding atmosphere are at a high temperature (700° C. can be exemplified as the temperature of the workpiece W). According to research conducted by the present inventors, when distance detection is performed in a high-temperature atmosphere, there is a tendency for the measured value to become larger than the actual distance. In such a case, it is desirable to treat the measured value as the actual distance by adding a predetermined correction to the measured value depending on the ambient temperature on the optical path and the length of the optical path passing through the high-temperature atmosphere.

As described above, according to the extraction system 75 of the present embodiment, the workpieces W arranged in a plurality of rows on the conveyor 20 can be detected without contact and the distance information of each row 2A to 2I can be acquired. The conventional detection rod that makes contact is no longer required, and the problems of misgripping the workpiece caused by the detection rod and waiting for extraction until the detection rod has finished rising can be resolved, increasing the productivity of extraction work.

In the extraction system 75 of this embodiment, the laser sensor 40 is arranged so that the laser beam passes through an area below the movable arm insertion area in the extraction opening 18. There is no need to provide a separate opening in the furnace wall, and the opening can be shared with the extraction opening 18 through which the movable arm 34 is inserted.

In the extraction system 75 of this embodiment, a heat shield plate 44 having a through hole 45 through which laser light passes is provided between the laser sensor 40 and the workpiece W, and the inner surface of the through hole 45 is processed black. There is. By doing so, the laser sensor 40 is prevented from being exposed to heat from the heat treatment furnace, and stray light is easily absorbed by the black surface formed on the inner surface of the through hole 45, resulting in false detection in the laser sensor 40. can be suppressed.

In the extraction system 75 of this embodiment, a hood is provided to cover three sides of the laser sensor 40 other than the front where the heat shield plate 44 is provided, and an air supply path 43 is provided to supply high pressure air to the space inside the hood. ing. By supplying high-pressure air to the space inside the hood where the laser sensor 40 is provided, it is possible to prevent dust from entering the hood and to prevent the laser sensor 40 from becoming hot.

Furthermore, in the extraction system of this embodiment, the focal position 51 of the laser beam irradiated toward the workpiece W is set at a position between the heat shield plate 44 and the workpiece W, thereby suppressing variations in distance detection. be able to.

Although the embodiments of the present invention have been described in detail above, this is merely an example. For example, the workpiece can have a shape other than a ring shape, and the gripping mechanism of the robot can be appropriately adapted to the shape of the workpiece. Further, the extraction operation illustrated in the above embodiment is merely an example, and the frequency and timing of detecting the distance to the workpiece can be changed as appropriate. Further, although the above embodiment is an example using a single extraction robot, the present invention does not depart from the spirit of the invention, such as by using multiple extraction robots together in some cases to execute the extraction operation. It can be implemented with various modifications within the scope.

2A to 2I Rows 10 Continuous heat treatment furnace 11 Furnace body 18 Extraction opening 20 Conveyor 34 Movable arm 36 Gripping part 40 Laser sensor (detection means)
43 Air supply path 44 Heat shield plate 45 Through hole 51 Focus position 60 Extraction robot 75 Extraction system W Work

Claims (6)

An extraction system for extracting workpieces arranged in multiple rows parallel to the conveyance direction on a conveyor of a continuous heat treatment furnace,
A laser beam is provided at a position facing each row of the workpieces on the downstream side of the conveyance direction outside the furnace body, and irradiates the workpiece located at the head of each row with a laser beam to measure the distance to the workpiece at the head. a detection means for detecting;
an extraction robot that has a gripping part at the tip of a movable arm and grips the workpiece on the conveyor and extracts it out of the furnace using distance information of each row sent out from the detection means;
An extraction system for a continuous heat treatment furnace characterized by comprising: irradiating the inside of the furnace with the laser light using an extraction opening formed in the furnace wall through which the movable arm is inserted when extracting the workpiece out of the furnace;
2. The continuous heat treatment furnace according to claim 1, wherein the detection means is arranged so that the laser beam passes through a region below a movable arm insertion region of the extraction opening. extraction system.
Claim 1, wherein a heat shield plate having a through hole through which the laser beam passes is provided between the detection means and the workpiece, and an inner surface of the through hole is processed to be black. , 2. The extraction system for a continuous heat treatment furnace according to any one of . A hood is provided to cover three sides of the detection means other than the front where the heat shield plate is provided, and an air supply path is provided for supplying high pressure air to a space within the hood. 3. The extraction system for the continuous heat treatment furnace according to 3. The continuous laser beam according to claim 3, wherein a focal position of the laser beam irradiated toward the workpiece is set at a position between the heat shield plate and the workpiece. Type heat treatment furnace extraction system. A method for extracting workpieces arranged in a plurality of rows parallel to the conveyance direction on a conveyor of a continuous heat treatment furnace, the method comprising:
A detecting means is provided at a position facing each row of the workpieces on the downstream side of the conveyor outside the furnace body, and a gripping section is provided at the tip of the movable arm to grip the workpieces on the conveyor and remove the workpieces from the furnace. Equipped with an extraction robot that extracts into
irradiating the workpiece located at the head of each row with a laser beam from the detection means to detect the distance to the workpiece at the head;
identifying a column located at the shortest distance from the extraction side end of the conveyor as an extraction target column using distance information of each column sent from the detection means;
a step of gripping a workpiece located at the head of the extraction target row by the extraction robot and extracting it out of the furnace;
A work extraction method characterized by having the following.

Images