JPH0248156Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a tube receiving device, and in particular, to a device that can smoothly rotate and feed a tube by keeping the circumferential speed of a turning roller for a tube receiving device constant. The present invention relates to a tube support device suitable for pipe joint welding.

"Prior Art" Conventionally, when welding or painting a pipe, a pipe support device has been used to continuously rotate the pipe little by little. As shown in FIG. 1, this conventional tube support device has a pair of left and right tube support turning rollers (hereinafter simply referred to as "turning rollers") 11, 21, 12, 2 when viewed from the P direction.
2,... are provided in plural sets at equal intervals in the front and back in the axial direction of the work tube 5, and one pair of any particular set has the same drive source, shaft, gear,
They are connected by a transmission mechanism of a joint pipe and are designed to rotate synchronously. In the case of welding work, first, the work tubes 5, 5 placed on the turning rollers 11, 21, . The turning rollers 11, 21, and 13, 23,...
While rotating the pipes 5, 5 to be worked on at the same speed, the welding rod 8 is brought close to welding. If welding is stopped when the workpiece tubes 5, 5 have rotated once, one round of seam welding is completed.

"Problem to be solved by the invention" However, the turning rollers 11 and 2
1, . . . are lined with rubber or the like on their outer peripheral surfaces so as not to damage the pipe 5 to be worked. This lining is subject to wear over time due to the pressing force and frictional force of the pipe to be worked 5, but due to some circumstances such as variations in the roundness of the pipe to be worked 5, the radius of one of the turning rollers may change. When the turning roller 30 becomes smaller than the others (see the dashed line A of the right turning roller 30 in FIG. 2), the circumferential speed of the turning roller 30 becomes smaller than the others because the entire turning roller 30 is rotated synchronously, and the workpiece pipe 5 in contact with this roller 30 (Refer to the two-dot chain line B) Sliding wear occurs, which gives vibration to the pipe 5 to be worked, which has an inconvenient effect on welding quality, coating quality, etc.

The present invention was developed in view of the drawbacks of the prior art, and aims to provide a tube support device that can improve work quality by keeping the circumferential speed of the turning roller constant at all times. purpose.

"Means and operations for solving the problem" In order to achieve the above object, the present invention drives a pair of left and right tube receiving turning rollers with individual induction motors, and the induction motors respond to changes in the motor slip. On the other hand, the torque has the characteristic of changing in a quadratic curve with a large curvature, and when one of the pipe receiving turning rollers becomes smaller in diameter due to wear etc., the torque for receiving and rotating the pipe to be spliced changes. At the same time, the power supply to the induction motor is controlled by a regulator so that the circumferential speed of the tube receiving turning roller can be kept approximately constant due to the change in rotation speed due to the change in motor slip due to the change in torque. The frequency can be adjusted in advance.

"Embodiment" Hereinafter, an embodiment of the present invention will be described based on FIGS. 3 to 6.

FIG. 3 is a perspective view showing the main parts of the welding tube support device according to the present invention. In this figure, 46,4
7 each indicates a driving turning roller part; 6
Reference numerals 1 and 62 indicate a supporting turning roller portion which does not have a driving portion and rotatably supports the pipe 5 to be spliced. Each of these turning roller parts is mounted on the pedestal 3.
It is equipped on 1,32. This frame 31,3
2 are installed on a straight line at a predetermined interval in the axial direction of the tube 5 (an interval that allows one tube 5 to be supported at multiple locations in the front and rear). One of the mounts 31 has two rails 4 made of two H-beams, front and rear, extending left and right when viewed from the direction of arrow P in the figure.
1 and 42 are end plates 43 and 44 and a bearing plate 4 to be described later.
It is integrated into 5th grade. Said rails 41, 42
On the top, driving turning roller parts 46 and 47 are placed, one on the left and one on the left. Now, to explain in detail the structure of the right driving turning roller section 47, first, a rectangular bottom plate 48 is slidably provided on the rails 41, 42 so as to straddle them. Bearing stands 49A, 49B are attached to the front and rear ends of the bottom plate 48 when viewed from the P direction, and a turning roller 52 is attached to a pair of bearings 50, 51 bolted onto each bearing stand 49A, 49B. ,
The tube 5 is rotatably supported with its rotation axis parallel to the central axis. The outer periphery of the turning roller 52 is a lining 5 made of pressure molded natural rubber or the like.
3 is applied to increase its durability.

A vertical support plate 54 is fixed to the front side of the bearing stand 49A, and a gear box 55 and an induction motor 56 for rotating the turning roller 52 are supported and fixed to the support plate 54. The gearbox 55 connects the induction motor 56 to the outside (right side) of the turning roller 52.
The rotational force of the induction motor 56 is transmitted to the turning roller 52 while being decelerated by an internal transmission mechanism and deceleration mechanism, and the tube 5 is moved at a constant speed via the turning roller 52. It is designed so that it can be rotated. The other turning roller section 46 is configured in exactly the same manner as the above-mentioned turning roller section 47, and the rails 41, 4 are arranged with the induction motor 56 on the outside (left side).
It is placed on 2.

Turning roller part 4 formed in this way
6, 47, the left turning roller part 46
is fixed near the left end of the rails 41, 42, while the turning roller section 47 moves on the rails 41, 42 by the action of a slide mechanism 57.
This makes it possible to adjust the interval between the turning roller parts 46 and 47 in accordance with the outer diameter of the pipe 5 to be worked. The slide mechanism 57 is shown in FIG.
As shown in FIG. 4, a feed shaft 58 rotatably supported by an end plate 44 and a bearing plate 45, and a bottom plate 4
8, a guide 59 (see FIG. 4) that protrudes downward through between the rails 41 and 42 and is screwed onto the feed shaft 58.
When the square columnar key part 60 protruding from the right end in FIG. 8 of FIG. 8 is rotated, the guide 59 and shaft 5
8, the turning roller section 46 is moved laterally. The other frames 32, . . . are also equipped with a slide mechanism 57 similar to that of the frame 31 described above. Moreover, the turning roller parts 46, 61...
and the right turning roller parts 47, 62, . . . are installed and adjusted so that their respective rotation center lines are on the same line.

As shown in FIG. 6, even if the lining 53 of the turning roller 52 is worn out and the diameter of the turning roller 52 is reduced and the torque is reduced, even if the induction motor 56 is operated under full load, as shown in FIG. The turning rollers 46 and 47, whose diameters have been reduced in this way, exhibit characteristics of torque versus rotational speed such that the circumferential speeds of the turning rollers 46 and 47 remain substantially constant without fluctuation.

Next, the operation of the tube support device having the above configuration will be explained.

Induction motor 56 of the turning roller section 47
For example, when a three-phase induction motor is used, the relationship between its rotational speed (slip S) and torque is as shown in Figure 5, and before and after full load, it is determined by the power supply frequency and the number of poles of the induction motor 56. Around the synchronous speed, the rotational speed and torque are almost proportional (see Figure 6).
On the other hand, in FIG. 2, when the radius of the turning roller 30 becomes smaller due to wear of the lining, even if the load P received from the tube 5 does not change, the distance between the load action line and the axis becomes shorter, so the roller axis becomes smaller. The torque applied to the radius decreases in proportion to the radius. Therefore, the torque required to rotate the turning roller 30 is also reduced. Considering this in the case of FIG. 3, the load torque of the induction motor 56 that rotates the turning roller 52 becomes smaller, so from the initially set, for example, full load state, the upper left along the solid line in FIG. The operating point moves in the direction and the rotational speed increases. This increase occurs in proportion to the decrease in torque. Here, an increase in the rotational speed of the induction motor 56 inevitably tends to cause an increase in the circumferential speed of the turning roller 52. Therefore, if the rotation speed-torque characteristics of the induction motor 56 are set in advance as shown in FIG.
Despite the reduction in radius due to wear of the lining 53, the circumferential speed of the turning roller 52 can be maintained constant at the time of its initial operation (see dotted line in FIG. 6).

If each of the other turning roller sections 47 is configured similarly to the above-mentioned turning roller section 46, the circumferential speed at the time of initial operation can be kept constant in exactly the same manner as described above, so that the tube 5 is always rotated at this circumferential speed, and there is no slippage between the tube 5 and the turning roller sections 46, 47, so that no vibration occurs in the tube 5.

However, since the torque value does not vary in a linear proportional relationship depending on the weight of the motor slip, that is, the tube 5 on which it is placed, the variation in the load applied to the turning roller is small as the diameter of the turning roller is reduced. However, in order to set the relationship between the motor slip and torque that can maintain the circumferential speed of the turning roller at a constant value even with this load variation, the relationship shown in Figs. 5 and 6 is determined by the weight of the tube 5. As is obvious, it is greatly influenced by

That is, the relationship between motor slip (slip S) and torque is not exactly proportional as shown in FIG. 5, but exhibits a quadratic curve-like relationship with a large curvature.
In particular, when the load on the tube 5 changes significantly, the motor slip (S = (Ns - Nr) / Ns, where Ns is the synchronous speed and Nr is the rotor speed) changes, and the torque and circumference change accordingly. The relationship with speed will deviate significantly from the state that is considered to be a constant value in terms of usage. For this reason, the frequency of the power supply supplied to the induction motor is varied to adjust the rotor speed Nr regardless of the motor slip value, and the circumferential speed of the turning roller is adjusted relative to the rotor speed Nr. As shown in FIG. 6, it is possible to maintain a constant value.
In other words, within the range of the variation in the load applied to the roller shaft as described above due to the diameter reduction due to wear caused by the use of the turning roller, the circumferential speed of the turning roller maintains a range in which it is considered to be a constant value during use. In order to make the speed Nr of the rotor follow the speed Nr of the rotor as much as possible, the rotational speed of the induction motor is set in advance by a regulator so that a region exhibiting the relationship as shown in FIG. 6 can be used. In this case, it goes without saying that the region in which the value of slip S rapidly decreases from around the peak value shown in FIG. 5 cannot be used. To change the frequency of the power supply, a widely used regulator using an inverter is usually used. This regulator is
As shown in FIG. 7, three-phase alternating current R, S, and T are first converted into direct current by a converter 70, and then converted into three-phase alternating current with a desired frequency and voltage value by an inverter 71, and then power is supplied to each motor 56. . The inverter 71 has a frequency set by a frequency setting volume VR, and is controlled by an inverter control circuit 72 so that the frequency of power supplied to the motor 56 becomes the set frequency.

The present invention is also useful for painting work, etc. in addition to the above-mentioned welding work.

"Effects of the Invention" As explained above, according to the present invention, even if one of the left and right turning rollers becomes smaller in diameter due to surface abrasion, the circumference of each turning roller can be adjusted without relying on human hands. Since the speed can be maintained constant, there is no vibration of the pipe, and therefore the quality of work such as welding and painting can be extremely high. There is no need for a long shaft, making assembly and installation of the tube support device easy.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing a conventional tube receiving device;
2 is an explanatory view of the operation of FIG. 1, FIG. 3 is a perspective view showing the main parts of the tube receiving device according to the present invention, FIG. 4 is a partial front view showing a part of FIG. 3, and FIG. 5 is a diagram showing the slip vs. torque characteristics of the induction motor in the tube support device shown in FIG. 3, and FIG. 6 is a diagram showing the torque vs. rotation speed characteristics of the induction motor in the tube support device shown in FIG. A diagram showing the characteristics of the circumferential speed of the turning roller portion, and FIG. 7 is a block diagram of an inverter-controlled regulator. 5...Pipe, 11, 12,..., 21, 22,...,
30, 52,... Turning roller, 56... Induction motor.

Claims (1)

[Scope of utility model registration request] In a tube support device equipped with a pair of left and right tube support turning rollers, each of the tube support turning rollers has a characteristic in which torque changes in a quadratic curve with a large curvature in response to changes in motor slip. The induction motors are connected to each other, and the induction motors have a rotational speed change range in which the circumferential speed of the tube support turning roller can follow a constant value in response to torque fluctuations due to changes in the diameter of the tube support turning roller. 1. A tube support device characterized by being provided with a regulator for varying a power supply frequency to be set within the range.