JPH06297141A - Automatic brazing device - Google Patents

Abstract

PURPOSE:To obtain an automatic brazing device in which the accurate grasp of a joined part, proper grasp of a feeding time for brazing and the proper control of the surface temp. of the joined part are each performed. CONSTITUTION:The device is provided with a means 1 for supplying brazing filler metal ('the metal') to the joined part B of a member A to be brazed and a torch 102 by which the metal supplied to the joined part by the means for supplying the metal is heated for brazing. The device is also provided with a position sensor 103 for optically detecting the position of the joined part B; a means 104, for compensating the attitude of the torch, by which the three dimensional coordinate data is obtained based on the detection signal of the position sensor and by which the attitude of the torch is made to follow up the positional deviation of the joined part as shown by the data; a surface temp. detecting means 105 by which the change in the surface temp. of the joined part is detected; a gas flow rate control means 106 by which the flow rate of a gas to be supplied to the torch is controlled in accordance with the change in the detected temp. ; and a means 107 for supplying the metal by which, each time the detected temp. indicated by the surface temp. detecting means reaches the liquidus line temp. of the metal, the metal supplying means is reactivated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic brazing apparatus for carrying out brazing work of a copper pipe joint, for example, by a robot.

[0002]

2. Description of the Related Art Conventionally, it has been widely practiced to automatically braze copper pipe joints and the like using automatic robots. In this case, it is important to automatically detect the position of the joint portion and follow the attitude of the torch.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 60-167787, the positional displacement amount of the joint portion is calculated based on the image data sent from the solid-state camera, and the robot arm is moved. Then, it was proposed to make the torch posture follow the displacement of the joint.

However, a system using a solid-state camera or the like is extremely expensive, and furthermore, when the surface has a metallic luster such as a copper pipe, there is a problem in that it lacks reliability. Therefore, conventionally, the position of the joint is generally determined by a jig that holds the joint, and the brazing is performed while automatically recognizing the position and correcting the attitude of the torch.

[0005]

However, when positioning is performed with a jig as in the prior art, it is practically impossible to further improve the accuracy of recognizing the displacement amount of the displacement of the joint. In addition, when the brazing material is supplied to the joint, it is conventionally set in advance by the timer function in the robot control panel, but this causes a problem that it is not possible to follow variations in the heat capacity of the brazed members. Furthermore, when controlling the gas flow rate to the torch that heats the joint to be brazed, conventionally, it was done by switching the strength of the two systems, but according to this, for example, copper has a small heat capacity, so that the joint The surface temperature cannot be controlled uniformly near the liquidus temperature of the brazing material.

Therefore, in the conventional case, in order to secure the desired joining strength, it is necessary to take measures such as increasing the length of the joining portion, and along with this, downsizing of the joining portion and shortening of brazing time, etc. Could not be planned.

The present invention has been made in view of the above problems, and its purpose is to accurately grasp the joint portion,
An object of the present invention is to provide an automatic brazing device capable of appropriately grasping the brazing material supply time and appropriately controlling the joint surface temperature.

[0008]

In order to achieve the above object, the present invention, as shown in FIG. 1, includes a brazing filler metal supplying means 101 for supplying a brazing filler metal to a joint B of a brazed member A, In an automatic brazing device provided with a torch 102 for brazing by heating the brazing material supplied to the joint B by the brazing material supply means 101, three-dimensional axial directions (X A position sensor 103 that optically detects one of the joints B from each axial direction), and three-dimensional coordinate data of the joint B is obtained based on the detection signal of the position sensor 103, and the obtained two-dimensional coordinate data indicates Torch posture correction means 1 for causing the posture of the torch 102 to follow the displacement amount of the displacement of the joint B.
04, a surface temperature detecting means 105 for detecting a change in the surface temperature of the bonding portion B, and a gas flow rate control means for controlling the gas flow rate to be supplied to the torch 102 according to the change in the detected temperature, which indicates the surface temperature detecting means 105. 106 and a brazing material supply control means 107 for restarting the brazing material supply means 101 each time the detected temperature indicated by the surface temperature detecting means 105 reaches the brazing material liquidus flow rate. Is.

[0009]

With the structure of the automatic brazing apparatus according to the present invention,
The joint B can be accurately grasped by the optical detection by the position sensor 103, and the torch posture correcting unit 104 shifts the posture of the torch 102 according to the accurate grasp of the joint B. The amount can be tracked.

Moreover, the change in the surface temperature of the joint B is constantly monitored by the surface temperature detecting means 105, and the gas flow rate control means 106 controls the gas flow rate supplied to the torch 102 under this monitoring. The surface temperature can be properly controlled.

Further, each time the detected temperature indicated by the surface temperature detecting means 105 reaches the brazing material liquidus temperature, the brazing material supplying means 107 restarts the brazing material supplying means 101.
Appropriately grasping the brazing material supply time, the brazing material is supplied at the joint B
Will be done against.

[0012]

FIG. 2 is a perspective view showing a main part and a brazed member of a robot to which the automatic brazing apparatus of the present invention is applied.

This robot has a structure including the respective parts shown in FIG. 1, and has an optical fiber photoelectric sensor 5 as a position sensor, which will be described later with reference to FIG. There are gas flow rate control positions 8a and 8b as gas flow rate control means, and these gas flow rate control devices 8a and 8b are gas flow rate control devices for oxygen and propane gas, respectively. However, from the viewpoint of responsiveness, it is desirable to select a gas flow rate control responsiveness of 1 SEC / 100% F · S or less. Further, there is an infrared radiation thermometer 7 as the surface temperature detecting means, and the infrared radiation thermometer 7 is non-contact, depending on the intensity of infrared rays emitted from the surface of the joint portion 4 of the brazed member 3 which is the heat exchanger body. The surface temperature of the joint portion 4 can be measured. However, it is desirable to select a scan time of 0.5 SEC or less from the viewpoint of responsiveness. Furthermore, a torch posture correction means and a brazing supply control means are provided on a robot control panel (not shown) that is the control center of the entire system. Has the function of. In addition, in FIG.
Reference numeral 1 is a torch, and the attitude of the torch 1 is corrected under the control of the torch attitude correction means of the robot control panel. Two
Indicates brazing wire. 3a and 3b respectively show a heat exchanger hot water supply pipe and a heat exchanger main body side pipe. 6 is a motor for storing the position sensor, and this motor 6 for storing the position sensor is
The purpose of this is to protect the optical fiber photoelectric sensor 5 from damage due to interference between the optical fiber photoelectric sensor 5 and the brazed member 3 during brazing, and burnout due to the need for the torch 1. 9
Reference numerals a and 9b are gas passages for supplying oxygen and propane, which are heat sources, respectively. Reference numeral 10 is a guide pipe for supplying a brazing wire. The brazing wire 2 is supplied to the guide pipe 10 by a brazing wire supplying motor 20 driven under the control of the brazing supply control means of the robot control board. To be done. Reference numeral 11 is a torch body, and the torch body is structured to be moved by the robot body 12.

FIG. 3 is a detailed explanatory view of the optical fiber photoelectric sensor 5. As shown, the optical fiber photoelectric sensor 5
Is an LED light emitting pipe 5a and an LED light receiving pipe 5
b. Reference numeral 19 indicates the optical axis of the optical fiber photoelectric sensor 5. In this figure, the optical fiber photoelectric sensor 5
Is moved in the robot coordinate X direction 13, the optical axis 19 is blocked by the brazed member X end surface 16, so that the optical fiber photoelectric sensor 5 sends a detection signal to the robot control panel.
As a result, the movement of the optical fiber photoelectric sensor 5 is stopped under the control of the robot control panel. The difference between the X coordinate value of the stopped robot coordinate and the X coordinate value of the reference position of the joint 4 previously input to the robot control panel is calculated in the robot control panel, and the calculated joint portion is calculated. The X direction deviation amount ΔX value is automatically stored in a storage unit in the robot control panel. This operation is similarly performed for the robot coordinate Y direction 14 and the Z direction 15, and the Y direction and Z direction deviation amounts ΔY and ΔZ values of the brazed members Y end surface 17 and Z end surface 18 are also stored in the storage unit in the control panel. Automatically memorize. Brazing by shifting the position of the torch 1 during brazing by the function of the torch posture correction means of the robot control panel by the amounts ΔX, ΔY, and ΔZ values due to the displacement of the joint portion 4 thus obtained. This makes it possible to achieve a high brazing joining rate, that is, accurate brazing.

In the robot of the present embodiment having the above-mentioned respective parts, first, as shown in FIG. 3, the optical fiber photoelectric sensor 5 is moved to the robot coordinates X, Y and Z in the directions 13, 14, and.
When moved to 15, the optical axis 1 of the optical fiber photoelectric sensor 5
9 is blocked by the brazed members X, Y, Z end faces 16, 17, 18. This point is the detection point in the robot coordinates X, Y, Z directions of the joint portion 4, and then the difference from the reference position of the joint portion 4 is calculated by the robot control panel, and the calculation is performed by the function of the torch posture correction means. The brazing can be performed accurately by shifting the position of the torch 1 during brazing by the amount of positional deviation indicated by the result and brazing.

Next, as shown in FIG. 2, each time the measured surface temperature of the joint 4 detected by the infrared radiation thermometer 7 attached to the torch 1 reaches the liquidus temperature of the brazing wire 2, the robot control is performed. The brazing wire supply motor 20 is restarted under the control of the function of the brazing material supply control means of the board to supply the brazing wire 2 to the joint 4. By this operation, the brazing can be performed by following the variation in the heat capacity of the joint portion 4,
A stable brazed joint state can be obtained.

At this time, the gas flow rate control devices 8a and 8b are adjusted in 15 steps under the control of the robot control panel according to the change in the surface temperature of the joint portion 4 detected by the infrared radiation thermometer 7. The surface temperature of the can be controlled uniformly, which results in a high quality joint crystal viscosity.

In this way, according to this embodiment, the brazing characteristics as shown in [Table 1] could be obtained. However, here, the brazing joining rate = (actual brazing length) /
(The brazing length required by the design) x 100 (%), and the amount of deviation given to the joint is plus or minus 3 mm, which is a general value for the accuracy of the assembly jig.

[0019]

[Table 1]

[Table 2] shows specifications of the sensor and the like used in the apparatus of this embodiment.

[0021]

[Table 2]

As shown in [Table 1], the brazing joining ratio in the case where there is a deviation in the joining portion was 70% or less according to the prior art, whereas it was 100% of this embodiment.

Further, according to the prior art, the brazing joining rate when the heat capacities of the members to be brazed are 0-10.
While it was indefinite between 0%, it was 100% according to the robot of this example.

The crystal viscosity of the brazed member at the joint is
According to the prior art, it is 0.25 mm or more, whereas according to this embodiment, it is 0.2 mm or less. As a result, the design limit value of the field where reheating stress acts on the joint is 0.2
It was possible to obtain a crystal viscosity of less than mm (Gen Sasaki: Fatigue behavior of non-oxidized copper and fractography P103, No. 19 of 1980, Copper and Brass Engineering Society). Therefore, the measure for increasing the length of the joining portion, which has been conventionally required, is completely unnecessary.

[0025]

As described above, according to the present invention, all of the accurate grasping of the joint portion, the proper grasping of the brazing material supply time, and the proper control of the joint surface temperature are achieved in the automatic brazing work. Therefore, the brazing quality can be significantly improved as compared with the conventional one.

[Brief description of drawings]

FIG. 1 is a block diagram showing a functional configuration of an automatic brazing device of the present invention.

FIG. 2 is a perspective view showing a main part and a brazed member in a robot to which the automatic brazing device of the present invention is applied.

FIG. 3 is a detailed explanatory diagram of an optical fiber photoelectric sensor.

[Explanation of symbols]

 1 Torch 2 Brazing Wire 3 Brazing Member 4 Joint 5 Optical Fiber Photoelectric Sensor 6 Position Sensor Storage Motor 7 Infrared Radiation Thermometer 8a, 8b Gas Flow Control Device 9a, 9b Gas Passage 10 Brazing Wire Supply Guide Pipe 11 Torch body 12 Robot body 13 Robot coordinate X direction 14 Robot coordinate Y direction 15 Robot coordinate Z direction 16 Braze member X end face 17 Braze member Y end face 18 Braze member Z end face 19 Position sensor optical axis 20 Braze wire Supply motor 101 Brazing material supplying means 102 Torch 103 Position sensor 104 Torch posture correcting means 105 Surface temperature detecting means 106 Gas flow rate controlling means 107 Brazing supply controlling means

Claims (1)

[Claims] 1. A brazing material supplying means for supplying a brazing material to a joint part of a brazed member and brazing by heating the brazing material supplied to the joint part of the brazed member by the brazing material supply means. In an automatic brazing apparatus including a torch, a position sensor that optically detects the position of the joint portion of the brazed member in the three-dimensional axial directions around the joint portion of the brazed member, Three-dimensional coordinate data of the joint portion of the brazed member is obtained based on the detection signal of the position sensor, and the torch posture is made to follow the torch posture to the amount of displacement of the joint portion indicated by the obtained three-dimensional coordinate data. Correcting means, surface temperature detecting means for detecting changes in the surface temperature of the joint portion of the brazed member, and gas for controlling the gas flow rate supplied to the torch according to the change in the detected temperature indicated by the surface temperature detecting means. Flow control means, and Each time the detected temperature indicated by the surface temperature detection means reaches a braze liquidus temperature, with an automatic brazing device characterized by comprising a, and the brazing material supply control means to restart the brazing material supply means.