JPH0661580B2 - Metal tube straightener - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a metal pipe straightening machine that straightens a bend by interposing a metal pipe between opposed rolls.

[Prior art]

The metal tube is often bent during the manufacturing process, and therefore is bent by a straightening machine. There are various types of straightening machines, and one of them is an inclined 7-roll straightening machine.

In the straightening machine of the inclined 7-roll type, as shown in FIG. 4, the roll 2-2-2-is provided on the downstream side of the pipe charging machine 6 for transferring the metal pipe P in the axial length direction (white arrow direction). The upper roll 1a, the lower roll 1b, the upper roll 2a, the lower roll 2b of the intermediate roll 2, the upper roll 3a, the lower roll 3b, and the auxiliary bending roll of the exit roll 3 are installed in the first type. It is equipped with 4.

All the above rolls 1a, 1b, 2a, 2b, 3a, 3b, 4 are moved up and down by a screw type rolling down device 5 equipped with a drive motor, and the opposing roll gaps are made slightly smaller than the pipe outer diameter. The metal pipe P is pressed down (crashed), and the middle upper and lower rolls 2a and 2b are displaced slightly upward (offset) from the upper and lower rolls 1a and 1b and the upper and lower rolls 3a and 3b. ) To apply bending stress to the metal tube P to correct the bending.

Therefore, when a metal pipe is straightened by the straightening system of this straightening machine (straightening machine I), the roll position is fixed, so that a large amount of pipe reduction can be achieved. A large rolling force was applied at a large circumferential position, and excessive residual stress was generated at this position, causing stress corrosion cracking.

For this reason, the applicant of the present application has proposed a straightening machine (straightening machine II) of a type in which a predetermined rolling force within a predetermined range is applied to a metal pipe to straighten it in order to prevent the occurrence of excessive residual stress (Japanese Patent Laid-Open No. 55-55- 128318
issue).

As shown in FIG. 5, this straightening machine uses hydraulic cylinders such as single-acting cylinders 11 and 11 on the lower rolls 1b and 3b on the inlet side and the outlet side in order to maintain the pipe pressure at a predetermined constant pressure. The upper roll 2a is provided with a hydraulic cylinder, for example, a double-acting cylinder 21, and pressure oil sent from the hydraulic pump 8 to the oil chambers of the single-acting cylinders 11 and 11 and the pipe pressure lowering oil chamber of the double-acting cylinder 21 is supplied to the relief valve 9. The pressure oil sent from the hydraulic pump 8 to the roll supporting oil chamber of the double-acting cylinder 21 corresponds to the load of the roll weight or the like in order to eliminate the influence on the pipe pressure due to the roll weight or the like. The pressure is supplied by adjusting the pressure with a relief valve 9 '.

For this reason, the metal pipe straightened by this straightening machine II has a constant crash amount at all circumferential positions regardless of the length of the outer diameter and no excessive residual stress is generated, but the shape before straightening is maintained. I could not hope to improve the roundness.

[Problems to be solved by the invention]

The required components, dimensional accuracy, mechanical properties, etc. of metal pipes differ depending on the application. For example, there is no possibility that stress corrosion cracking will occur. When correcting the bending of the metal pipe to be used, it is better to use the former straightening machine I, and the dimensional accuracy,
In particular, the latter straightening machine II should be used when straightening the bending of a metal pipe that is loosely specified for roundness and is strictly defined for stress corrosion cracking.

When straightening the bending of a metal pipe whose regulation on stress corrosion cracking is somewhat lenient and whose roundness is strict, both of the straightening machines I and II are not necessarily appropriate. There has been a problem that the I and II correction methods alone cannot sufficiently perform the optimum correction according to the application, material characteristics and the like.

[Means for solving problems]

The present invention has been made to solve such problems, and there is no regulation regarding stress corrosion cracking, and a straightening machine I is used for straightening the bending of a metal pipe when dimensional accuracy is strictly regulated.
The straightening method by the straightening machine II and the straightening method by the straightening machine II for the straightening of the bending of the metal pipe when the regulation of the dimensional accuracy, especially the roundness is loose and the stress corrosion cracking is strictly regulated. When the roundness is somewhat gradual and the roundness is strictly regulated, a certain pressure is applied to the roll to correct the bend of the metal pipe, and the pressure of the hydraulic fluid in the hydraulic cylinder is increased by the force received from the metal pipe of the roll. An object of the present invention is to provide a metal tube straightening machine capable of selectively switching and using a third straightening method for preventing backflow of a pressurized liquid when the pressure is equal to or higher than a predetermined pressure.

The metal pipe straightening machine according to the present invention is equipped with a screw type pressure reducing device on one of the facing rolls and a hydraulic pressure reducing device on the other side, and a roll gap is provided between the screw type pressure reducing device or the screw type pressure reducing device and the hydraulic pressure reducing device. In a straightening machine which passes a metal tube between opposed rolls to be adjusted and gives a crush to it, it is provided between a hydraulic cylinder for adjusting a roll gap and the hydraulic cylinder and a hydraulic pressure source. It is provided between the pressure regulator and the hydraulic cylinder, which sets the pressure of the hydraulic fluid to a predetermined pressure and supplies it to the hydraulic cylinder. A first valve that blocks the backflow of the pressure fluid from the hydraulic cylinder to the pressure regulator side when the pressure of the fluid exceeds the predetermined value, and release the backflow inhibition of the pressure fluid by the first valve, or Allows back flow of pressure fluid from the hydraulic cylinder to the pressure regulator side And a second valve which is provided between the pressure regulator and the hydraulic pressure source and which switches between the supply of the pressure fluid to the pressure regulator and the recirculation of the pressure fluid from the hydraulic cylinder. It is characterized by

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the drawings. FIG. 1 is a schematic view showing an embodiment of the present invention, in which P indicates a straightened metal tube. The metal pipe P is moved in the axial direction (white arrow direction) by the pipe loading machine 6 and the metal pipe straightening machine 10
The roll arrangement of the metal tube straightening machine 100 is a 2-2-2-1 vertical 7-roll system.

The entrance-side upper roll 1a, the intermediate lower roll 2b, the exit-side upper roll 3a, and the auxiliary bending roll 4 are supported by the conventional screw-type reduction devices 5, 5, 5, and 5, respectively.
The output side lower roll 3b is supported by the hydraulic pressure reduction devices 10, 10, and the intermediate upper roll 2a is supported by the screw type reduction device 5'and the hydraulic pressure reduction device 20, respectively.

The heights of the rolls 1a, 2b, 3a, 4, 1b, 2a, 3b are adjusted by the respective rolling down devices 5, 5 ', 10, 20 and the respective hydraulic rolling down devices 10 for the rolls 1b, 2a, 3b. , 20, the pipe pressure can be adjusted.

A single-acting cylinder 11, which is a hydraulic cylinder, is provided at the pivotal support of each of the lower rolls 1b and 3b on the inlet side and the outlet side, and its oil chamber 11a is fed from a hydraulic pump, not shown, which is a hydraulic pressure source. The pressure oil in the common pipe 40 through which the pressure oil is flowing is sent to the pressure reducing valve 14, which is a pressure regulating valve, via a solenoid valve 15 that is a second valve of a 3-port 2-position switchable type that can switch between refueling and recirculation. The pressure oil decompressed in (1) is supplied through the check valve 12 which is a first valve through which oil can flow to the oil chamber 11a side. A relief valve 13 is mounted between the pressure reducing valve 14 and the check valve 12 and is set to a pressure higher than the pressure set by the pressure reducing valve 14. Further, the check valve 12 is provided with a bypass pipe line 10c forming a hydraulic circuit member in parallel, and when the opening / closing valve 17 installed in the middle thereof is opened, the oil chamber 11a and the cylinder 11 of the pressure reducing valve 14 are opened. It is possible to communicate with the side.

A bypass pipe line 10b is provided in parallel between the cylinder 11 side of the check valve 12, the opening / closing valve 17 and the common pipe 40 side of the pressure reducing valve 14,
Along the way, a check valve 16 that allows oil to flow to the common pipe 40 side
Is attached, and when the solenoid valve 15 is switched to the recirculation position, the pressure oil in the oil chamber 11a can be recirculated.

A double-acting cylinder 21, which is a hydraulic cylinder, is provided at the pivotal support portion of the intermediate upper roll 2a, and the rod advancing (lower side) oil chamber 21a supplies the pressure oil of the common pipe 40, It can be sent to the pressure reducing valve 27 via the solenoid valve 28 which is a 3 port / 3 position switching type second valve that can be switched to stop and return, and the pressure oil reduced here can be flowed to the oil chamber 21a side. It is designed to be supplied via a check valve 25 which is a first valve. A relief valve 26 is attached between the pressure reducing valve 27 and the check valve 25, and is set to a pressure higher than the pressure set by the pressure reducing valve 27.

The check valve 25 includes a bypass line (the hydraulic circuit member) 20.
c is installed side by side, and the open / close valve 30 installed midway
When is opened, the oil chamber 21a and the cylinder 21 side of the pressure reducing valve 27 are made to communicate with each other.

Between the cylinder 21 side of the check valve 25 and the opening / closing valve 30 and the common pipe 40 side of the pressure reducing valve 27, the bypass pipeline 20b is provided in parallel,
Along the way, a check valve 29 that allows oil to flow to the common pipe 40 side
Is attached, and when the solenoid valve 28 is switched to the recirculation position, the pressure oil in the oil chamber 21a can be recirculated.

On the other hand, the oil chamber 21 for rod withdrawal (upper side) of the double-acting cylinder 21
The b is supplied with pressure oil at a pressure necessary to eliminate the influence of the roll 2a's own weight on the pipe rolling force.
The oil chamber 21b is sent to the pressure reducing valve 22 via the 3-port 2-position switching type solenoid valve 24 capable of switching the pressure oil in the common pipe 40 between refueling and recirculation, and the pressure oil depressurized to the set pressure here is supplied. Supplied. The pressure reducing valve 22 is provided with a bypass pipe line 20e in parallel,
A check valve 23 that allows oil to flow to the common pipe 40 side is attached midway along the line, and when the electromagnetic valve 20 is switched to the return position, the pressure oil in the oil chamber 21b can be returned.

The solenoid valves 15, 24, 28 can be switched by a control device (not shown) based on the purpose, material, dimensional accuracy, etc. of the metal pipe to be straightened.

[Action]

In the metal pipe straightening machine according to the present invention configured as described above, the solenoid valves 15 and 28 are switched to the return flow to remove the pressure oil from the oil chamber 11a of the single-acting cylinder 11 and the oil chamber 21a of the double-acting cylinder 21, and the electromagnetic solenoid The valve 24 is switched to oil supply, pressure oil is supplied to the oil chamber 21b of the double-acting cylinder 21, and the roll height and roll are adjusted by the screw-type reduction devices 5 and 5'without applying hydraulic reduction to the rolls 1b, 2a, 3b. When the gap is set, there is no flow of pressure oil due to the solenoid valves 15 and 28, so the roll gap between the rolls 1, 2 and 3 is always kept constant at the gap set by the screw type rolling down devices 5 and 5 '. Therefore, the outer diameter can be made constant over the entire circumference, and the crush amount Cm can be made large as shown in (a) of FIG. 2, and an excessive crush amount Cm 'can be imparted to the pipe P in the long diameter portion of the pipe. .

Therefore, in this case, the straightening method is the same as that of the straightening machine I, there is no regulation on stress corrosion cracking, and the bending of the metal pipe whose dimensional accuracy is strictly regulated can be corrected.

If the roll gap is slightly expanded from the above-mentioned state by a screw-type reduction device to open and close the on-off valves 17 and 30 and the solenoid valves 15 and 28 are switched to allow lubrication, single-acting cylinder 11 and double-acting cylinder
The pressure oil pressure between the oil chambers 11a and 21a of 21 and the pressure reducing valves 14 and 27 related to them is constantly adjusted to the set pressure of the pressure reducing valves 14 and 27,
Also, the force received from the roll side suddenly increases and the oil chamber 11
When the pressure oil pressure inside a, 21a is higher than the pressure set by pressure reducing valves 14, 27, it becomes higher than the pressure set by relief valves 13, 26.
Is operated to release the pressure oil, a constant rolling down force is applied to the pipe P, and even if the pipe outer diameter changes as shown in (b) of FIG. The crush amount Cc can be applied to the pipe P.

Therefore, in this case, the straightening method is the same as that of the straightening machine II, and it is possible to straighten the bending of the metal pipe P in which the dimensional accuracy, particularly the roundness, is loosely regulated and the stress corrosion cracking is strictly regulated.

Further, when the on-off valves 17 and 30 are closed and the solenoid valves 15 and 28 are switched to be able to refuel, pressure oil adjusted to the set pressure of the pressure reducing valves 14 and 27 is supplied to the oil chambers 11a and 21a. , When the pressure in the oil chambers 11a, 21a becomes higher than the set pressure, the check valves 12, 25 work, and the pressure on the common piping side is higher than the cylinder side of the check valves 16, 29. Due to this, backflow is prohibited, so that a predetermined pressure acts on the pipe P at the pipe outer diameter portion where the oil pressure in the oil chambers 11a, 21a becomes smaller than the set pressure, that is, the portion where the pipe outer diameter is small, and the pipe P crashes in a predetermined crash. You will receive the amount.
Further, in the pipe outer diameter portion where the oil pressure in the oil chambers 11a, 21a is larger than the set pressure, that is, in the portion where the pipe outer diameter is large, a reduction force of a predetermined pressure or more acts on the pipe P, and the pipe P has a predetermined crash amount or more. You will get a crash.

Therefore, in this case, as shown in (c) of FIG. 2, a constant crush amount Cc is given to the short diameter portion of the pipe, and a larger crush amount Cc 'is given to the long diameter portion of the pipe. For this reason, it is difficult to straighten in the past, and a straight pipe having a slightly loose regulation on stress corrosion cracking and a strict regulation on roundness can be manufactured, and a straightening method not provided by the straightening machines I and II can be obtained.

As described above, the metal pipe straightening machine according to the present invention has the opening / closing valves 17, 30,
By appropriately opening and closing the solenoid valve and switching the solenoid valves 15 and 28, it is possible to select the most suitable correction method based on the material properties of the metal pipe P, application, etc. It is possible to manufacture straight pipes with strict circularity regulations.

FIG. 3 is a sectional view of the single-acting cylinder 11 portion attached to the roll 1b taken along the line III-III in FIG. 1, showing a roll angle adjusting device. This device has push rods 52a, 52b spline-coupled to the respective shaft cores of gears 55a, 55b that are rotated in the opposite direction by a gear 55c provided on the shaft of a drive motor 53, and a screw part formed in the middle thereof. Screw holes 11a, 11b opened in cylinder 11
The push rod 52 that moves in and out by screwing into
It is configured to push the piston 50 at the tip of a or 52b to rotate it, and to rotate the rod 51 which is fitted to the piston 50 by this rotation and which is fixed to the pivotal support of the roll 1b. The rotation control is performed by detecting the number of rotations by the rotary encoder 54 provided on the shaft of the drive motor 53, giving the detection result to the comparator 57 via the A / D converter 56, and the comparator 57 is set by the setter 58. And A / D converter corresponding to the roll angle to be changed set by
Drive motor 53 so that the value input from 56 is the same value.
It is made by rotating.

Further, the rotation control as described above is also applied to the adjustment of the roll height, and the roll height adjusting device is the screw type rolling down device 5
And the drive motor 63 provided in the double-acting cylinder 21 is driven by the same setter, comparator, A / D converter, rotary encoder 64, etc. as before, so that the screw of the screw type screw-down device 5 and the screw of the double-acting cylinder 21 are It is configured to rotate the formed rod by a required amount.

By the roll angle adjusting device and the roll height adjusting device,
Conventionally, complicated roll angle adjustment and roll height adjustment can be automatically performed. Therefore, the roll angle and height can be changed at any time according to the pipe diameter, and the change can be made quickly.

In the above embodiment, the 2-2-2-1 type 7-roll type metal pipe straightening machine is applied, but the present invention is also applied to other types of metal pipe straightening machine having opposed rolls. it can.

Further, although oil is used in the above-mentioned embodiments, the present invention is not limited to oil, and other liquids may be used.

Further, although the on-off valves 17 and 30 of the manually operated type are used in the above embodiment, the present invention can be carried out by replacing them with the automatically controlled type.

Further, it goes without saying that the present invention can be implemented by using a manually operated type instead of the solenoid valves 15, 24, 28.

Further, in the above embodiment, the check valves 1
Although 7,7 are arranged in parallel, the present invention configures a hydraulic circuit member that can prevent the reverse flow from the hydraulic cylinder to the pressure regulator side instead of the check valves 12 and 25, and that enables the reverse flow. Valve may be used, and if the valve is used, bypass pipes 10c, 20
c can be eliminated.

〔effect〕

As described above in detail, the present invention can selectively use three types of pipe pressure reduction methods by a simple operation for the hydraulic circuit member and the first and second valves. It can be optimally used for metal pipes with different straightening purposes, which is advantageous in terms of equipment cost and installation space for straightening machines, and is excellent in that it can be used in conformity with the production of small variety of small rods. Produce the effect.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention, FIG. 2 is an explanatory view of correction contents when the correction method of the metal pipe straightening machine according to the present invention is changed, and FIG. 3 is a metal pipe straightening according to the present invention. Sectional views of the roll angle adjusting device of the machine, FIG. 4 and FIG. 5 are schematic sectional views showing a conventional straightening machine. P ... Metal tube, 1, 2, 3, 4 ... Roll, 10, 20 ...
Hydraulic pressure reduction device, 11 …… single acting cylinder, 21 …… double acting cylinder, 12,25 …… check valve, 13,26 …… relief valve, 14,27…
… Pressure reducing valve, 15, 28… Solenoid valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Publication No. 48-1291 (JP, B1) Japanese Patent Publication No. 4-42095 (JP, B2) Japanese Patent Publication No. 62-47608 (JP, B2)

Claims (1)

[Claims] 1. An opposed roll having a screw type reduction device on one of the opposed rolls and a hydraulic pressure reduction device on the other side, and the roll gap is adjusted by the screw type reduction device or the screw type reduction device and the hydraulic pressure reduction device. In a straightening machine that gives a crash to this by passing a metal tube between them, a hydraulic cylinder that adjusts the roll gap, and the pressure of the hydraulic liquid that is provided between the hydraulic cylinder and the hydraulic pressure source and is sent from the hydraulic pressure source. Is set between the pressure regulator and the hydraulic cylinder to set a predetermined pressure to the hydraulic cylinder, and the force of the roll from the metal tube causes the pressure of the hydraulic fluid in the hydraulic cylinder to The first valve that prevents the backflow of the pressure fluid from the hydraulic cylinder to the pressure regulator side when the value exceeds a predetermined value, and either release the backflow prevention of the pressure fluid by the first valve or adjust it from the hydraulic cylinder. Hydraulic circuit section that allows backflow of pressure fluid to the pressure side And a second valve which is provided between the pressure regulator and the hydraulic pressure source and which switches between supplying the pressure fluid to the pressure regulator and circulating the pressure fluid from the hydraulic cylinder. Metal tube straightening machine.