JP2006344421A - High frequency induction heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high frequency induction heating device capable of carrying out high frequency hardening or annealing at a high quality level even if an object to be heated has a complicated shape. <P>SOLUTION: A portable type heating head 1 is held by a robot 2. A robot control part 3 controls the track and the speed of the robot 2, and teaches the robot the track and the speed in accordance with the shape of a work. A high frequency control part 4 controls the output and the frequency of the heating head. The heating head 1 is provided with a temperature sensor, and pre-heating is applied to the work with a prescribed output and a prescribed traveling speed. In accordance with the surface temperature of the work which the temperature sensor obtains by the pre-heating, the output, the traveling speed, and the track at the time of hardening and annealing are modified. Thereby, high hardening and annealing quality can be obtained even if the work has a complicated shape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-frequency induction heating apparatus that can efficiently and surely quench and anneal.

  In the high frequency induction heating, a high frequency current is passed through a coil, and Joule heat of an eddy current generated thereby causes internal heating of the object to be heated. Such high frequency induction heating has the following characteristics.

  (1) The object to be heated can be heated to a high temperature and high temperature without contact.

  (2) Heating efficiency is good because the object to be heated self-heats.

  (3) The heating temperature can be controlled by controlling the output.

  (4) Local heating is possible.

Because of these characteristics, high frequency induction heating is used for various applications. For example, it is also used for quenching large metal parts such as automobile parts, and a high-frequency quenching apparatus that performs quenching while conveying a work has been proposed (for example, see Patent Document 1).
JP 2002-371234 A

  In the induction hardening apparatus described in Patent Document 1, the work moves relative to the heating coil, the part of the work that needs to be quenched is continuously heated, and then a coolant or the like is sprayed onto the heated part. To cool quickly. A diffusion prevention plate is provided around the cooling liquid ejecting portion so that the cooling liquid is applied to the workpiece being heated and unnecessary cooling is not performed.

  However, the induction hardening apparatus described in Patent Document 1 needs to be designed exclusively for the shape of the workpiece that is the object to be heated, the size and shape of the workpiece are limited, and a workpiece having a complicated shape is quenched. There was a problem that could not be done. In addition, there is a problem that the induction hardening apparatus becomes larger as the shape and dimensions of the workpiece become larger.

  Furthermore, such an induction hardening apparatus has a problem that high quenching quality cannot be obtained. That is, if the shape of the workpiece is complicated, the gap between the heating coil and the workpiece changes depending on the location, and the heating temperature is not uniform. In this case, there is a problem that the hardness of the workpiece after quenching and the quenching depth vary depending on the location. Further, when the gap is small and the heating temperature is too high, the work may be cracked.

  An object of the present invention is to provide a high-frequency induction heating apparatus that can perform induction hardening or annealing with high quality even for an object to be heated having a complicated shape.

  A high-frequency induction heating apparatus according to the present invention includes a portable heating head that induction-heats an object to be heated by flowing a high-frequency current, a heating head control unit that sets an output of the heating head, and a holding head that holds the heating head. And a robot control means for setting the moving speed and trajectory of the robot.

  In the present invention, a portable heating head is held by a robot and moved along the shape of an object to be heated. By moving along the shape of the object to be heated, the heating temperature becomes uniform even with a curved object to be heated, and high quenching and annealing quality can be obtained. Moreover, since moving heating is performed by a robot that sets a trajectory along the shape of the object to be heated, quenching and annealing can always be performed under the same conditions. In addition, since the robot holds the portable heating head and moves and heats it, the apparatus does not increase in size even if the shape or size of the object to be heated increases.

  The present invention further comprises a temperature sensor for detecting the surface temperature of the object to be heated, and a memory that records the relationship between the surface temperature and the output of the heating head, the robot moving speed, or the trajectory, and the heating head control means And the robot control means preheats the object to be heated with a predetermined output, moving speed, and trajectory, and after the preheating, based on the detected value of the temperature sensor and the memory contents, the output of the heating head, It is characterized by performing the main heating by correcting the moving speed of the robot or the trajectory of the robot.

  In this invention, the surface temperature of the object to be heated is detected by a non-contact temperature sensor. Prior to the induction hardening and annealing processes, preheating is performed in advance at a predetermined output and moving speed. The preheating is performed by heating to such an extent that the material characteristics of the object to be heated do not change. The surface temperature is detected by preheating, and the memory contents are referred to by the detection result, and the output of the heating head, the moving speed of the robot, and the trajectory of the robot are corrected accordingly. That is, the above parameters are corrected according to the heating location so that the surface temperature is uniform. In places where the surface temperature is low due to preheating, the output is increased, the moving speed is reduced, or the trajectory is adjusted so that the head approaches the workpiece. As a result, higher quenching and annealing quality can be obtained, and by controlling these parameters, the heating temperature can be controlled, and the workpiece can be controlled to a desired hardness and quenching (annealing) depth. .

  The present invention further includes a plurality of injection means for injecting quenching coolant or compressed air, and switching means for switching and supplying the quenching coolant or compressed air to the injection means. It is characterized by that.

  In this invention, the injection nozzle which can inject a fluid thing is provided. The spray nozzle switches between the quenching coolant and the compressed air by the switching mechanism and sprays. Accordingly, the heating head can be moved not only in a single direction but also in a plurality of directions for quenching. For example, bi-directional quenching and annealing can be performed.

  As described above, according to the present invention, since the robot holding the portable heating head moves along the shape of the object to be heated and performs induction heating, what is the size and shape of the object to be heated. However, it is possible to heat evenly, and it is possible to obtain high quenching quality by suppressing variations in hardness and depth of the workpiece after quenching and annealing.

  In addition, by controlling the output of the heating head, the moving speed of the robot, and the gap, the heating temperature can be controlled, and the workpiece after quenching and annealing can be controlled to a desired hardness and depth.

  Moreover, since the robot holds the portable heating head and moves and heats it, it is not necessary to increase the size of the device even when the shape and size of the object to be heated is increased, and the quenching coolant and compressed air are used. The operation of the robot can be simplified by switching.

Hereinafter, the high frequency induction heating apparatus according to the embodiment of the present invention will be described in detail.
FIG. 1 is an external view showing a high frequency induction heating apparatus according to an embodiment of the present invention. As shown in the figure, the high frequency induction heating apparatus includes a portable heating head 1, a robot 2 that holds and moves the heating head 1, a robot control unit 3 that controls the operation of the robot 2, and an output of the heating head 1. The high frequency control part 4 which controls is provided.

  The heating head 1 is configured by a coil or the like that allows high-frequency current to flow (see FIG. 2), and is connected to the high-frequency control unit 4 by a flexible cable. Therefore, the heating head 1 can be moved freely and can be moved in a predetermined path by the connected robot 2. Details will be described later.

  The high frequency control unit 4 includes a power source that supplies a high frequency current, an oscillator, and the like, and controls the output of the high frequency current that flows through the heating head 1. Here, a transistor inverter type oscillator is used. By using a transistor inverter type oscillator, a high frequency (for example, 120 KHz) and a high output (30 KW) can be realized. Note that other types of oscillators may be used.

  The robot 2 holds the heating head 1 and is an industrial robot that moves the heating head 1 three-dimensionally according to the control of the robot control unit 3. The robot control unit 3 controls the trajectory and speed of the robot 2. The trajectory and speed of the robot 2 can be taught in advance, and the same movement can be performed repeatedly under specified conditions.

  FIG. 2 is an external view showing a heating head portion of the high-frequency induction heating apparatus according to the embodiment of the present invention. As shown in FIG. 1, the heating head 1 includes a heating coil 11 for supplying a high-frequency current, and an injection unit 12 and a temperature sensor 13 before and after the heating coil 11. Further, the heating head 1 includes a robot attachment portion 21 for connecting to the robot 2.

  Under the control of the high-frequency control unit 4, the heating coil 11 causes a high-frequency current to flow and induction-heats an object to be heated (work). When a high frequency current is passed through the heating coil 11, an alternating magnetic field is generated. An eddy current is induced in the workpiece by the alternating magnetic field, and the workpiece self-heats due to Joule heat. In such high frequency induction heating, the heating temperature of the workpiece can be controlled by controlling the output of the high frequency current. In general, the workpiece can be heated to about room temperature to about 1000 ° C.

  Although the heating coil 11 can take various shapes according to the shape of the workpiece, in the present embodiment, the heating coil 11 is a substantially rectangular (hollow rectangular parallelepiped) coil. Of course, coils other than this shape may be used. For example, when heating a workpiece having a curved surface, a coil curved in a convex shape (or concave shape) may be used along the curved surface. Although the workpiece | work which is a to-be-heated object can consider various shapes and materials, it is the metal mold | die for resin molding, the steel member for motor vehicles etc., for example. The heating coil 11 includes a pipe (not shown) that circulates cooling water for cooling the coil inside, and has a structure that suppresses self-heating due to high-frequency current by circulating the cooling water.

  A plurality of (two in the present embodiment) jetting units 12 are installed before and after the heating coil 11 to jet a fluid to the work surface. Each injection unit 12 includes a plurality of nozzles for injecting a fluid. One of the injection units 12 is supplied with compressed air, and the other injection unit 12 is supplied with a quenching coolant. Whether to supply compressed air or quenching coolant to each injection unit 12 is determined by an injection control mechanism (described later) connected to the injection unit 12.

  The injection unit 12 that injects the cooling liquid sprays the quenching cooling liquid onto the surface of the work that has been induction-heated to a high temperature by the heating coil 11 to rapidly cool the work. As a result, the workpiece is quenched, and thus the workpiece quenched and quenched after high-temperature heating has a hard surface, excellent wear resistance, and a long-life metal member.

  The injection unit 12 that injects compressed air blows air near the surface of the heating coil 11 to prevent the quenching coolant from splashing. By blowing air near the surface of the heating coil 11, air can be shielded near the heating coil, and the coolant can be prevented from being scattered on the work surface.

  The temperature sensor 13 is a non-contact temperature sensor installed in the vicinity of the heating coil 11, and is constituted by, for example, an infrared sensor in which thermocouples are arranged in series. The temperature sensor 13 can measure the surface temperature of the work heated by induction by the heating coil 11. By measuring the temperature of the workpiece surface, it is possible to detect variations in the heating temperature depending on the location of the workpiece. Note that a plurality (two in the figure) of the temperature sensors 13 are also provided before and after the heating coil 11, so that the heating head 1 can be moved in either the front or rear direction.

  The robot mounting portion 21 is a connection mechanism for connecting to the robot 2 described above, and the robot 2 can hold and move the heating head 1 through this.

  In the high frequency induction heating apparatus of the present invention, the robot 2 holds the heating head 1 and moves it along the shape of the workpiece, thereby moving and quenching or annealing at a uniform temperature even for a workpiece having a complicated shape. It can be carried out.

  Next, the configuration of the high frequency induction heating apparatus will be described in detail. FIG. 3 is a block diagram of the high frequency induction heating device according to the embodiment of the present invention. As shown in the figure, the high frequency induction heating apparatus includes a heating head 1, a robot 2, a robot control unit 3, a high frequency control unit 4, a calculation unit 5, a memory 6, and a supply control unit 7.

  The heating coil 11 of the heating head 1 is connected to the high frequency control unit 4. The injection unit 12 is connected to the supply control unit 7, and the supply control unit 7 is connected to the high frequency control unit 4. The temperature sensor 13 is connected to the calculation unit 5, and the robot control unit 3, the high frequency control unit 4, and the memory 6 are connected to the calculation unit 5. The robot control unit 3 is connected to the robot 2.

  The supply control unit 7 is an injection control mechanism that supplies compressed air and quenching coolant to the injection unit 12 and controls them. As described above, either the compressed air or the quenching coolant is supplied to the plurality of injection units 12, and the supply control unit 7 determines which one is supplied.

  The supply control unit 7 is supplied with compressed air from a compressed air supply source such as an air compressor or a factory line, and supplies quenching coolant from a coolant supply source having a water pump or a tank. is recieving. The supply control unit 7 has a switching mechanism that can select and supply either compressed air or quenching coolant to the plurality of injection units 12.

  The calculation unit 5 acquires the surface temperature data of the workpiece from the temperature sensor 13. Further, the position (trajectory) and moving speed of the robot 2 are acquired from the robot control unit 3, and the output set value of the heating coil 11 is acquired from the high frequency control unit 4. The computing unit 5 can compare the relationship between the workpiece surface temperature, the position of the robot 2, the moving speed, and the output of the heating coil 11 in real time. In addition, the calculation unit 5 can set the trajectory and movement speed of the robot 2 controlled by the robot control unit 3, and can also set the output of the heating coil 11 controlled by the high frequency control unit 4. .

  The arithmetic unit 5 teaches the trajectory and movement speed of the robot 2. The user or the like who uses this high-frequency induction heating device sets the trajectory of the robot 2 in advance. Further, a plurality of setting conditions assuming various works at the time of factory shipment may be stored in the memory 6. The user of the high-frequency induction heating device may select any setting condition. The arithmetic unit 5 teaches the robot 2 by inputting the trajectory set by the user to the robot control unit 3. FIG. 4 shows a schematic diagram of the quenching and annealing process. As shown in the figure, the heating head 1 is moved along the workpiece 8 by the robot 2. The user of the high-frequency induction heating device sets in advance so as to have a trajectory along the workpiece 8, and the robot 2 moves in the trajectory set by the control of the robot control unit 3.

  Of the workpiece 8, the vicinity of the heating coil 11 is heated by induction heating. In the quenching step, the substrate is heated to a high temperature of about 800 ° C., for example. At this time, compressed air and quenching coolant are injected from the injection unit 12. The quenching coolant is sprayed from the spraying section 12 that is installed behind the heating head 1 in the moving direction. Compressed air is injected from the injection part 12 installed ahead of the moving direction. The supply control unit 7 switches between jetting of compressed air and coolant according to the moving direction of the heating head 1. That is, the supply control unit 7 receives information on the moving direction of the heating head 1 from the calculation unit 5 via the high frequency control unit 4 and controls to inject compressed air in front of the movement and inject cooling liquid in the rear of the movement. To do. Thus, quenching can be performed in both directions by switching the compressed air and the coolant according to the moving direction. In the annealing step, the coolant is not sprayed, but the annealing can be performed in both directions as described above.

  After the workpiece 8 is heated to a high temperature, it is rapidly cooled by the quenching coolant. As the heating head 1 continuously moves, the entire surface of the workpiece 8 is rapidly cooled and quenched after being heated at a high temperature. In such a quenching process, the hardness and depth (depth to be quenched) after quenching change by changing the heating temperature of the workpiece 8 and the cooling rate. Also, in the annealing process, the hardness and depth change by changing the heating temperature.

  The heating temperature becomes higher as the output of the heating coil 11 is higher, the gap between the heating coil 11 and the workpiece 8 is narrower, and the moving speed of the robot 2 is slower. The rate of cooling varies depending on the type of quenching coolant. Quenching water or quenching oil is used as the quenching coolant. Generally, quenching water is cooled at high speed, and quenching oil is cooled at low speed. These conditions are changed depending on the material of the workpiece, and the hardness and depth after quenching are controlled.

  Furthermore, the high frequency induction heating device according to the embodiment of the present invention performs the following operation. The calculation unit 5 instructs the robot control unit 3 and the high frequency control unit 4 to perform preheating at a predetermined output, moving speed, and trajectory. In the preheating, moving heating is performed at a temperature at which the material characteristics of the workpiece 8 do not change. For example, the surface temperature of the workpiece 8 is heated to about 200 ° C. In the preliminary heating, the workpiece 8 is moved along the workpiece 8 at a constant output and moving speed. The supply control unit 7 performs control so that the compressed air and the coolant are not injected from the injection unit 12 during the preliminary heating.

  The temperature sensor 13 detects the surface temperature of the workpiece 8 during the preheating. The calculation unit 5 acquires the surface temperature of the workpiece 8, the output of the heating coil 11, the moving speed and the position of the robot 2 in real time. Therefore, the workpiece surface temperature variation can be detected by preheating. The arithmetic unit 5 corrects the output of the heating coil 11, the moving speed of the robot 2, and the position (mainly the gap) so as to eliminate the variation in the surface temperature and make it uniform.

  The calculation unit 5 has a database in which the relationship between the workpiece surface temperature, the output of the heating coil 11, the movement speed of the robot 2, and the gap is described in the memory 6 according to the material of each workpiece, and is detected by preheating. It is possible to perform a correction operation by referring to this database using the workpiece surface temperature. Various conditions can be changed manually. After preheating at a constant output, speed, and gap, refer to variations in workpiece surface temperature and manually change the output, speed, and gap at each position.

  Thereby, it becomes possible to make the hardening (annealing) hardness and depth of the whole workpiece more uniform, and high quenching quality can be obtained.

  As described above, the high-frequency induction heating apparatus according to the embodiment of the present invention moves along a workpiece while the robot holds a portable heating head, so even a complex-shaped workpiece moves in three dimensions. It can be heated and can be heated and cooled uniformly. Also, preheating is performed to such an extent that the material properties of the workpiece do not change, the temperature distribution on the workpiece surface is measured, the output of the heating head, the robot movement speed, the robot trajectory so that this workpiece surface temperature distribution is uniform. Is corrected, so that higher quenching and annealing quality can be obtained. Moreover, the temperature of this heating can be changed by setting said parameter variously, and quenching (annealing) hardness and depth can also be controlled.

  In addition, the high frequency induction heating apparatus of this invention can also be used for uses other than quenching and annealing. It can also be used for general applications of high-frequency induction heating, such as brazing, soldering, and welding.

1 is an external view of a high frequency induction heating device according to an embodiment of the present invention. 1 is an external view of a heating head portion of a high-frequency induction heating device according to an embodiment of the present invention. The block diagram of the high frequency induction heating apparatus which concerns on embodiment of this invention. Schematic diagram showing the quenching and annealing process

Explanation of symbols

1-Heating head 2-Robot 3-Calculation unit 4-High frequency control unit 5-Robot control unit 6-Memory 7-Supply control unit 8-Work

Claims (3)

A portable heating head for inductively heating an object to be heated by passing a high-frequency current;
Heating head control means for setting the output of the heating head;
A robot that holds the heating head and moves the vicinity of the object to be heated at a predetermined speed and orbit,
Robot control means for setting the moving speed and trajectory of the robot;
A high-frequency induction heating device equipped with. A temperature sensor for detecting the surface temperature of the object to be heated;
It further includes a memory that records the relationship between the surface temperature and the output of the heating head, the robot moving speed, or the trajectory,
The heating head control means and the robot control means preheat the article to be heated with a predetermined output, moving speed, and trajectory, and after the preheating, based on the detected value of the temperature sensor and the memory contents, The high frequency induction heating apparatus according to claim 1, wherein the heating is performed by correcting the output of the heating head, the moving speed of the robot, or the trajectory of the robot. A plurality of injection means for injecting quenching coolant or compressed air;
The high-frequency induction heating apparatus according to claim 1, further comprising switching means for switching and supplying quenching coolant or compressed air to the spraying means.

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