JPH0212676B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electron beam welding device that performs welding in a vacuum atmosphere using the impact heat of an electron beam accelerated at a high voltage of several tens of kilovolts, and particularly relates to a vacuum evacuation device. .

Fig. 1 is a piping diagram showing a vacuum evacuation device of a conventional electron beam welding device, in which 1 is a sealed welding chamber;
2 is an electron gun mounted on the ceiling of this welding room 1;
3 is a vacuum valve for opening and closing the vacuum pipes 9 and 10; 4 is a mechanical booster pump for evacuating the inside of the welding chamber 1; 5 is connected in parallel to this mechanical booster pump 4; a safety valve for preventing overload from acting on the pump 4; 6 an oil rotary vacuum pump for evacuating the welding chamber 1; and 7 connected to the vacuum piping 10 to enable the mechanical booster pump 4 to operate. 8 is a leak valve for supplying air into the welding chamber 1; 9 is a vacuum pipe connecting the welding chamber 1 and the vacuum valve 3; 10 is the vacuum valve 3; and the mechanical booster pump 4, 11 is a vacuum pipe that connects the mechanical booster pump 4 and the oil rotary vacuum pump 6, and 12 and 13 connect the safety valve 5 to the mechanical booster pump 4 in parallel. Vacuum piping for this purpose. The exhaust capacity of the mechanical booster pump 4 and oil rotary vacuum pump 6 is set appropriately according to the production volume of the workpieces (not shown) in the welding room 1, and The welding output of this kind of electron beam welding equipment used in industry is usually 20 seconds to 30 seconds.
This is about one piece per second, and the time required to vacuum the welding chamber 1 is 10 to 15 seconds.

The evacuation device of the conventional electron beam welding device is configured as described above, so after fixing a predetermined workpiece (not shown) in the welding chamber 1 and closing the leak valve 8, the oil is removed. When the rotary vacuum pump 6 is started and the vacuum valve 3 is opened at the same time, the welding chamber 1 is evacuated by the oil rotary vacuum pump 6 via the mechanical booster pump 4 which has been stopped. This vacuum evacuation increases the pressure in the welding chamber 1 to 50 to 150 torr, which is the operating pressure of the mechanical booster pump 4. When it reaches
The vacuum switch 7 sends a signal to the starting switch of the mechanical booster pump 4, which starts the mechanical booster pump 4, and the welding chamber is filled with the suction force of both the oil rotary vacuum pump 6 and the mechanical booster pump 4. The pressure inside 1 is evacuated to below 0.05 torr, which is the welding pressure. Generally, the pressure inside the welding chamber 1 is the operating pressure of the mechanical booster pump 4.
The time required to evacuate to 50 to 150 torr or less is 2 to 3 seconds.

When the pressure in the welding chamber 1 reaches the welding pressure of 0.05 torr or less using the procedure described above, the workpiece (not shown) in the welding chamber 1 is welded by the electron gun 2. It is designed to be welded. When the specified welding of the object to be welded is completed,
After the vacuum pipes 9 and 10 are temporarily disconnected by closing the vacuum valve 3, the leak valve 8 is opened to supply air into the welding chamber 1, and the welded workpiece is removed from the welding chamber 1. It is designed to take out the welded material. The safety valve 5, which is connected in parallel with the mechanical booster pump 4, is designed to prevent damage to the vacuum piping 9 or 10 due to some kind of accident, causing a large amount of air to flow into the vacuum piping and overloading the mechanical booster pump 4. This is provided to prevent this from acting as a nuisance.

As mentioned above, according to the vacuum evacuation device of the conventional electron beam welding equipment, although the evacuation time required to reach the operating pressure of the mechanical booster pump 4 of 50 to 150 torr is extremely short at 2 to 3 seconds. First, since it cannot be started simultaneously with the oil rotary vacuum pump 6, an external signal is required to start the mechanical booster pump 4, and not only is the vacuum switch 7 required to extract the external signal, but also the vacuum Not only does it have to incorporate an expensive sequence device that starts the mechanical booster pump 4 in response to a signal from the switch 7, but the vacuum piping 10 has to be made longer to attach the vacuum switch 7. This increases the size of the device, and it is also troublesome to set the pressure of the vacuum switch 7. Furthermore, according to the conventional vacuum evacuation device described above, in order to take out the workpiece after welding from the welding chamber 1, it is necessary to bring the inside of the welding chamber 1 to atmospheric pressure each time. Even if the workpiece to be welded is stored in the welding chamber 1 and the vacuum valve 3 is opened, the pressure in the welding chamber 1 does not reach the operating pressure of the mechanical booster pump 4 (50 to 150 torr), so every time welding is completed, Another drawback is that an expensive sequence device for stopping the mechanical booster pump 4 must be incorporated.

This invention was made with attention to this point, and the flow rate of gas related to exhaust is adjusted in a vacuum valve provided between an exhaust system consisting of a mechanical booster pump and an oil rotary vacuum pump and a welding chamber. The flow rate of gas passing through the vacuum valve and flowing into the exhaust system for at least a few seconds immediately after the vacuum valve opens, that is, until the welding room reaches a vacuum level sufficient to operate the mechanical booster, is provided. The present invention aims to provide a vacuum evacuation device for electron beam welding equipment that can smoothly start a mechanical booster and an oil rotary vacuum pump from atmospheric pressure by adjusting the opening of the buttful valve so as to narrow down the It is something to do.

That is, although FIG. 2 shows one embodiment of the present invention, the same reference numerals as those in the above-mentioned conventional device (FIG. 1) refer to the same constituent members, and the explanation thereof will be omitted.

Reference numeral 14 denotes a full valve inserted between the vacuum pipes 9 and 10 between the welding chamber 1 and the mechanical booster pump 4 together with the vacuum valve 3;
The opening is kept slightly open until several seconds have passed to suppress the flow of gas flowing into the mechanical booster pump 4, and then it is fully opened to quickly increase the vacuum level in the welding chamber 1 to increase the conductance of the exhaust system. increase. The buff-full valve 14 may be controlled by, for example, using a delay relay so that the buff-full valve 14 is driven several seconds after the vacuum valve 3 is driven, but in this embodiment, the vacuum valve 3 and the buff-full valve 14 are The air is supplied to the air cylinders of the vacuum valve 3 and the buttful valve 14 at the same time by being driven by a cylinder, and adjusting the flow rate of air flowing out from this air cylinder so as to slowly increase their opening degrees. A simple sequence was adopted.

According to the present invention, since it is configured as described above, even if the oil rotary vacuum pump 6 and the mechanical booster pump 4 are started at the same time after the work to be welded is housed and fixed in the welding chamber 1, the vacuum valve 3
Due to the action of the buff-full valve 14 which is connected to the vacuum valve 3 and operates at the same time as the vacuum valve 3, a large load is not applied to the mechanical booster pump 4, so that the mechanical booster pump 4 exhibits sufficient functionality. For example, as mentioned above, the evacuation time required to reach the operational pressure of 50 to 150 torr for a normal mechanical booster pump is 2 to 3 seconds, so the opening/closing time of the vacuum valve 3 is set to 2 to 3 seconds. In addition, the time required for the full valve 14 to fully open is set so that the vacuum valve 3 is fully opened within that time, and the degree of opening of the vacuum valve 3 is initially set small and then gradually increased. If this is set so that the full valve 14 is also fully opened in synchronization with this after 2 to 3 seconds, the mechanical booster pump 4
It is also possible to start the oil rotary vacuum pump 6 at the same time from atmospheric pressure (760 torr).

As described above, the present invention has an extremely simple configuration in which the vacuum valve 3 is inserted between the welding chamber 1 and the mechanical booster pump 4 and operates simultaneously with the buttful valve 14. 6 and the mechanical booster pump 4 can be started at the same time from atmospheric pressure, which not only eliminates the need to incorporate expensive sequence equipment as in the past and can be provided at low cost, but also improves the operation of electron beam welding. The contribution is extremely large.

Although the above-mentioned embodiment has been described with respect to a vacuum evacuation device for an electron beam welding device, it goes without saying that the present invention can be implemented in any other devices that utilize a mechanical booster pump and an oil rotary vacuum pump.

[Brief explanation of drawings]

FIG. 1 is a piping diagram showing a vacuum evacuation device of a conventional electron beam welding device, and FIG. 2 is a piping diagram showing an embodiment of the present invention. In the drawings, 1 is a welding room, 2 is an electron gun, 3 is a vacuum pump, 4 is a mechanical booster pump, and 6 is an oil rotary vacuum pump. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A vacuum valve inserted between a welding chamber equipped with an electron gun and a mechanical booster pump connected to an oil rotary vacuum pump, which is capable of adjusting the flow rate of gas passing through the vacuum valve. and a control means for driving the buff-full valve so as to suppress the flow rate of gas related to evacuation for a predetermined period after the vacuum valve is opened for evacuation of the welding chamber. Vacuum exhaust equipment for electron beam welding equipment. 2. According to claim 1, the welding chamber is further provided with a speed adjusting means for gradually increasing the opening degree of the vacuum valve and the buff-full valve when the vacuum valve is opened to evacuate the welding chamber. A vacuum evacuation device for the electron beam welding device described.