JPS63108997A - Method for driving all positioned welding equipment - Google Patents

Abstract

PURPOSE:To eliminate the chattering between tooth wheels and to stably travel a welding truck by installing to the welding truck two motors having slight difference in the number of revolutions at the same rated torque and traveling the truck via a pinion and rack by the slight difference in the revolutions. CONSTITUTION:Two motors 2a, 2b are simultaneously driven and a welding truck 6 is traveled along a truck rail via the engagement of pinions 3a, 3b and a rack 1 via speed reducing machines 5a, 5b. In this case when the same rated torque is intended to obtain by impressing a voltage V on the motors 2a, 2b, an error is caused in the number of revolutions. The chattering between tooth wheels is absorbed via the engagement of the pinions 3a, 3b and rack 1 by this error is revolutions. With this method the generation of a backlash among tooth wheels can be prevented and the whole welding equipment can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for driving an all-position welding device.

[Prior Art] All-position welding equipment is used for welding the entire circumference of fixed pipes, etc., and is usually equipped with a ring-shaped track rail around the outer periphery of the pipe, and a welding cart is engaged with the track rail. A pinion is attached to the shaft of a motor installed on the welding cart, and by driving the pinion, the welding cart is caused to travel in the circumferential direction through engagement between the pinion and a ring-shaped rack provided on the track rail. That's how you get it.

By the way, when welding a pipe in all positions, it is necessary to make the welding cart run smoothly in order to make the welding uniform. However, since the above-mentioned welding cart travels through engagement between the pinion and the rack, the welding cart does not run smoothly due to play between the tooth surfaces of the pinion and the rank, that is, backlash, resulting in uneven welding. turn into.

Therefore, as shown in Japanese Utility Model Application No. 59-62883, a mechanism has been devised to prevent the above-mentioned backlash by applying an appropriate braking force to the welding cart during traveling.

[Problems to be solved by the invention] However, in this conventional method, the motor that drives the pinion must have a capacity to overcome not only the weight of the welding die itself but also the braking force. . Therefore, in the past, it was necessary to attach a large and long motor to the welding cart, which required a large amount of space around the pipe during welding.

The present invention was developed in view of these circumstances.

[Means for Solving the Problems] The present invention provides an all-position welding apparatus in which a track rail equipped with a ring-shaped rack is mounted on the outer circumference of a pipe, and a welding cart is run along the track rail. Two motors with the same rated torque and a slight difference in rotational speed are installed on a welding cart, and the pinions attached to each motor are meshed with the rack, and due to the slight difference in rotational speed, the pinion and the south side of the rack are connected. This system allows the welding cart to travel while absorbing the backlash.

[Function] If there is a difference in rotation speed with the same rated torque, one motor will pull or push the other motor through the engagement between the pinion and rack, eliminating play between the tooth surfaces.
Welding carts provide stable running.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

The figure schematically shows an apparatus for carrying out the method of the present invention, where ① is a rack provided in a ring shape along a track rail attached to a pipe, and the first motor 2a is attached to the rack ①. By meshing the pinion 3a attached to the second motor 2b and driving the motors 2a, 2b, the welding cart 6 is moved along the track rail in the circumferential direction through the meshing of the pinions 3a, 3b and the rack 1. It is configured so that it can be run on.

The motors 2a and 2b have the same rated torque but slightly different capacities such that there is a slight difference in rotation speed,
and the total capacity is configured to be equal to the capacity of a conventional motor,
Furthermore, they are connected in series. Note that 4 is a rotation speed detector, 5a and 5b are speed reducers, and 6 is a welding cart.

In the present invention, the two motors 2a and 2b are simultaneously driven to cause the welding cart 6 to travel along the track rail through the meshing of the pinions 3a and 3b with the rack 1. In this case, if an attempt is made to obtain the same rated torque by applying voltage to the motors 2a and 2b, an error will occur in the output due to the difference in capacity Ω, that is, an error will occur in the rotation speed. This rotational speed error causes one motor 2a or 2b to pull or push the other motor 2b or 2a through the engagement between the pinions 3a, 3b and the rack 1, thus causing the pinions 3a, 3b and the rack 1 to The play between the south face and the south face is absorbed, preventing backlash from occurring.

By the way, motors commonly available on the market have the same rated capacity Q.
However, due to variations in precision during manufacturing, some differences in rotation speed, torque, output, etc. are allowed, and there are almost no products with exactly the same capacity. Therefore, it is within the scope of the present invention to use motors with half the capacity of conventional motors as the first motor 2a and second motor 2b.

[Effects of the Invention] As explained above, according to the present invention, the play between the tooth surfaces of the pinion and the rack is absorbed by utilizing the error in the rotational speed of the two motors17, thereby causing backlash. This eliminates the need for a large, long motor that has the capacity to overcome brake forces in the brake mechanism as in the past, making it possible to make the entire welding equipment compact. It can produce excellent effects such as reducing the space around the tube.

[Brief explanation of the drawing]

The figure is a schematic diagram of an apparatus for carrying out the method of the invention. 1 is a rack, 2a and 2b are motors, 3a and 3b are pinions, and 6 is a welding cart.

Claims (1)

[Claims] 1) In an all-position welding device in which a track rail equipped with a ring-shaped rack is attached to the outer circumference of the pipe and a welding cart is run along the track rail, there is a slight difference in rotational speed with the same rated torque.2 The motors of the stand are installed on the welding cart, the pinions attached to each motor are engaged with the rack, and the welding cart is run while absorbing the play between the tooth surfaces of the pinion and rack due to the slight difference in the rotation speed. A method of driving an all-position welding device characterized by the following.