JPH0156876B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a cutter body for electric resistance welded pipes, which is equipped with a mechanism for alleviating the impact force on the cutting tool when cutting the inner bead of the electric resistance welded pipe with a cutting tool. As shown in Figure 1, in a conventional internal bead cutting machine, a beam-shaped mandrel is inserted into the inner surface of the ERW pipe from the opening, and the part 8 to which the cutting tool 11 is attached is called the cutter body. However, a bottom roll 6 supported by a spring 7 is attached to this to fix the position of the cutting tool 11, and a bottom roll 6 to press the cutting tool 11 and the top rolls 9, 10 against the inner surface of the tube.
When cutting the inner bead 5 with such a cutter body, cutting with a hard bit tip to increase wear resistance generally makes it brittle, so the bit breaks off in a much shorter time than it takes to reach its wear life. Put it away. In recent years, due to higher speeds and thicker walls, there has been an increasing need to use brittle bit materials with higher wear resistance and hardness, and there are many cases of bits chipping. The method of changing the cutting tool involves drilling a hole in the pipe with a gas cutter, moving the hole to the cutter body, and replacing the cutting tool, which further reduces the mill's work efficiency. In the current cutter body, the impact that causes damage to the cutting tip occurs. First of all, as shown in FIG. In the second case, as shown in Fig. 3, due to twisting of the ERW welded pipe, the deviation 13 between the top roll center and the bead center suddenly becomes too large, and the top roll changes as shown in Fig. 3. As if, it rides on the bead 14, and this is the impact when it tries to return to its original position. 4, 5, and 6 show the direction of the force applied to the cutting tool 11. In each of the above cases, the Z-direction component fz of the cutting force F applied to the cutting tool 11 becomes large, and normally the direction of the force applied to the cutting tool 11 increases. The condition shown in Fig. 5 changes and the bite tip is lost. Thirdly,
When the mill stops, the main component of cutting disappears and there is only a backward force, resulting in a force state as shown in Figure 5. In addition, the pipe usually moves backward at the same time as the mill stops. As a result, the direction of fz becomes opposite, resulting in the direction of the force as shown in Figure 6, which makes it very likely that defects will occur. Figure 4: The shape of an ERW steel pipe after welding changes due to changes in the shape of the material or insufficient adjustment of the pipe production line. For example, in addition to the above-mentioned twisting of the pipe, there is also a change in the diameter of the pipe in the vertical direction. As a result of these fluctuations, as shown in Fig. 7, the cutting tool shifts from the normal cutting position as indicated by the solid line 15 relative to the bead 14 to the cutting position as indicated by the broken line 16 and the dashed dotted line 17, which occurs with some degree of periodicity. Repeat with . At this time as well, the state of force in Figure 5 appears. The purpose of the cutter body of the present invention is to improve the shortcomings of these conventional devices and extend the life of the cutter. Next, the structure of the cutter body of the present invention will be explained. The present invention provides the following features: (1) A roller having a rotating shaft is provided on the rear upper surface of a cutting tool for cutting an inner bead of an electric resistance welded pipe, and the shaft of the roller is further provided with a spring along a bearing groove provided at an angle backward. A cutter body for electric resistance welded pipes, which is characterized by a slide operation using air pressure or hydraulic pressure to reduce impact force during bead cutting, etc. (2) A lever-shaped beam with a rotating shaft as a fulcrum is provided behind the cutting tool that cuts the inner bead of the electric resistance welded pipe, and a roller is provided at one end of the upper surface of the beam at the rear of the cutting tool, and the other end is equipped with a spring or hydraulic pressure. Alternatively, a cutter body for electric resistance welded pipes is characterized in that the roller swings during bead cutting by pressing with an air cylinder, etc., to alleviate the impact force. (3) The cutter body for electric resistance welded pipes as set forth in item 2 above, characterized in that the roller is provided with a clutch that is locked when the roller is reversed. First, schematic diagrams of examples of a cutter body, which is the first aspect of the present invention, are shown in FIGS. 8, 9, and 10. As shown in the figure, this cutter day is
A roller 18 is provided behind the cutting tool 11, and the roller 18 and the shaft 20 are integrated or tight-fitted, and a spring 23
(FIG. 8), the bearing 22 is pushed by an air cylinder 31 (FIG. 9), or a hydraulic cylinder 32 (FIG. 10), and is movable in the groove forming the slope 23. Next, other embodiments of the present invention are shown in FIGS. 11 and 12.
As shown in FIG. Byte 1 as shown in the figure
1 At the rear, a spring 30 (Fig. 11), an air cylinder 31 (Fig. 12), or a hydraulic cylinder 32 is installed.
(Fig. 13) Beam 29 with fulcrum 33 supported by
A roller 28 is attached to the tip of the beam to enable the beam to swing in the direction of the tube axis. It is preferable to use a commercially available clutch in which the roller 28 is movable only in the direction of the arrow and is locked in the opposite direction. When using the cutter body of the present invention,
This has the effect of alleviating the drawbacks described in the first, second, and fourth points mentioned above. When a force is applied due to the impact force shown in the defects described in the first, second, and fourth defects, the cutting tool always transitions from the state shown by the solid line 15 in FIG. 7 to the state shown by the broken line 16 in FIG. In other words, the spring, hydraulic cylinder, or air cylinder supporting the roller 18 or 28 is compressed, and the force supported by the roller 18 or 28 increases. As a result, the force applied to the cutting tool 11 is reduced and fz does not rise suddenly, and by appropriately selecting the spring constant and the spring force, hydraulic pressure, air pressure, and friction force that support the roller, fx commensurate with the rise in
fz can be increased. This is the buffering effect. In order to prevent the transition from the state shown by the solid line 15 to the state shown by the broken line 16, it is possible to consider a method of attaching a fixed roller to the rear of the cutting tool, but this method makes it difficult to adjust the vertical position of the cutting tool when the wall thickness changes and the inner diameter changes. Therefore, it is necessary to replace rollers with different diameters in response to the change in diameter, resulting in poor workability. When the impact is removed, kinetic energy is applied to the rollers 18 and 28 to move them up and down, and vibrations may remain. In such a case, please refer to Figures 8 to 1.
In the case of FIG.
Kinetic energy is consumed as work of frictional force with the axis of 8, eliminating vibration. Further, as the roller 18 rotates, the bearing 22 tilts, and similarly a frictional force with the slide slope 23 acts, thereby eliminating vibration. In order to have the effect of eliminating this vibration, it is necessary to adjust the slope of the slide slope, the roller 18 and the shaft center 20.
In order to adjust the diameter ratio between the diameter and the groove width between the diameter and both slide slopes, the thickness and friction coefficient of the slide bearing, the surface properties can be adjusted by adjusting the pipe inner diameter, pipe wall thickness, pipe material, bottom roll spring force or hydraulic pressure, spring 25, the spring constant of the air cylinder, and in the case of hydraulic pressure, the spring constant of the spring 26. When using the cutter body shown in FIGS. 11 to 13, the swing center axis diameter of the beam 29 and the beam 29
By selecting the fit between the shaft and the shaft, the above damping effect can be obtained. Furthermore, when escaping the impact when the vehicle stops, the mechanism for escaping the impact differs depending on the illustrated example. First, when the cutter bodies shown in FIGS. 8 to 10 are used, when the pipe moves in the opposite direction 24 due to spring back as shown in FIG. By being pushed down by a distance of 19, the cutter body is also pushed down by a distance of 19, and the cutting tool tends to move away from the inner surface of the pipe, so that chipping of the cutting tool can be prevented. In this case as well, the inclination of the slide slope, the ratio of the diameter of the roller 18 to the diameter of the shaft 13, the shaft diameter, the groove width between both slide slopes, the thickness of the slide bearing, the adjustment of the friction coefficient, and the spring constant of the bottom roll. , the spring constant of the spring 25 or the spring constant of the air cylinder, and in the case of hydraulic pressure, the spring constant of the spring 26 and the spring constant of the hydraulic system.
In other words, these conditions are arbitrarily combined and adjusted so as to optimize the impact relief effect and the impact relief effect when the vehicle is stopped. Once these adjustments are made, they hardly need to be changed and are easy to operate. When the cutter body shown in FIGS. 11 to 13 is used, when the cutter body stops and the force to rotate the roller 28 disappears, the force that tries to bend the spring or compress the air cylinder via the beam 29 is generated. By reducing the force, or in the case of hydraulic pressure, the force that compresses the spring 34, the beam 29 is reduced as shown in FIG.
is swung by an angle of 27, that is, the cutter body is lowered by an interval of 35, and the bite is also at an interval of 3.
The position that has dropped by 5 is the equilibrium position, and
When the tube moves backward due to springback, roller 28
Since the cutter body is locked and does not rotate, the beam swings further and the cutter body lowers. Therefore, by moving the cutting tool away from the inner surface of the tube, chipping of the cutting tool can be prevented. Table 1 shows the results of examining the presence or absence of missing bites by repeatedly stopping the cutter body of the present invention. FIG. 16 is a diagram showing the effect of using the cutter body of the present invention, where curve a shows the life of a highly wear-resistant cutting tool and curve b shows the life of a normal cutting tool. The cutter body of the present invention was used to perform bead cutting with a highly wear-resistant bit material, and the life was measured.As shown in Figure 16a, the cutter body had conventionally been damaged up to the solid line (point 26). However, as shown by the dashed line, the cutting tool does not break, so it is now possible to use the cutting tool to its full life.

[Table] As explained above, by using the cutter body of the present invention, it is possible to reduce the impact that occurs during bead cutting during ERW steel pipe manufacturing, such as the step at the coil relay section, the top roll running onto the bead, and the mill stopping. It is possible to reduce the impact of fluctuations in the position of the cutting tool during cutting without causing vibration. Therefore, the cutter body of the present invention can use a cutting tip that has a longer wear life than conventional cutter bodies.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of bead cutting in conventional electric resistance welding, Figure 2 is a diagram showing the step at the intermediate joint, and Figure 3 is a diagram showing the step at the intermediate joint.
The figure shows the top roll riding on the bead, Figures 4 to 6 show the direction of the force applied to the bit, Figure 7 shows the relative positional relationship between the bit and the bead, and Figures 8 to 6. Fig. 10 is a schematic diagram of the slide roller type cutter body of the present invention;
Figures 13 to 13 are schematic diagrams of the swing roller type cutter body of the present invention, Figure 14 is a diagram of the principle of shock relief when stopped, Figure 15 is an explanatory diagram of the swing of the swing roller, and Figure 16 is a diagram of the cutting tool body. It is a figure showing cutting life. 1... Welding equipment, 2... External bead, 3... External bead cutting tool, 4... Pipe-making pipe, 5...
Inner bead, 6... bottom roll, 7... bottom roll pressing mechanism, 8... cutter body,
9,10...Top roll, 11...Inner bead cutting tool, 13...Top roll and deviation from bead center, 14...Inner bead, 15,1
6, 17...Cutting tool position, 18...Slide roller, 19...Distance pushed down by the slide roller, 20...Slide roller axis, 21
... Position fluctuation of slide roller axis due to intermediate step, 22 ... Slide bearing, 23 ... Slide slope, 25 ... Spring, 26 ... Area where damage occurs in conventional cutter body, 27 ... Swing angle of swing roller, 28...Swing roller, 29...
... Swing beam, 30 ... Spring, 31 ... Air cylinder, 32 ... Hydraulic cylinder, 33 ... Swing axis, 34 ... Spring, 35 ... Distance at which the cutter body is pushed down by the swing roller.

Claims (1)

[Scope of Claims] 1. A roller having a rotating shaft is provided on the rear upper surface of a cutting tool for cutting the inner bead of an electric resistance welded pipe, and the shaft of the roller is provided with a spring along a bearing groove provided tilting backward. A cutter body for electric resistance welded pipes, which is characterized by sliding motion using air pressure or hydraulic pressure to alleviate impact force during bead cutting, etc. 2. A lever-like beam with a rotating shaft as a fulcrum is provided behind the cutting tool that cuts the inner bead of the electric resistance welded pipe, and a roller is provided at one end of the upper surface of the beam at the rear of the cutting tool, and the other end is equipped with a spring, hydraulic pressure, air cylinder, etc. A cutter body for electric resistance welded pipes, which is characterized by a roller that swings during bead cutting, etc., by pressing the roller, reducing the impact force. 3. The cutter body for an electric resistance welded pipe according to claim 2, wherein the roller is provided with a clutch that is locked when the roller is reversed.