JPH0516050U - Circular saw cutting machine for steel pipe cutting - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the cutting efficiency when cutting a steel pipe using a circular saw. [Structure] In a circular saw cutting machine that rotates a circular saw by a circular saw rotating mechanism and cuts the steel pipe by sending the circular saw to a steel pipe by a saw blade feeding mechanism, a low speed drive that drives the saw blade feeding mechanism at a low speed. A mechanism, a high-speed drive mechanism that drives the saw blade feed mechanism at high speed, and a control circuit that operates the high-speed drive mechanism in a cutting region where the saw blade load is below a predetermined load and the low-speed drive mechanism in a cutting region where the saw blade load is above a predetermined load. To provide. When cutting a steel pipe, high-speed feed is performed in a cutting region where the saw blade load is below a predetermined load, and low-speed feed is performed in a cutting region where the saw blade load is above a predetermined load.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a circular saw cutting machine for cutting steel pipes, and more particularly to a circular saw cutting machine for improving the cutting efficiency of steel pipes.

[0002]

[Prior Art]

 In steelmaking factories, various cutting machines are used to cut off defective parts such as steel ingots and steel pieces, or to cut steel pieces and steel plates to desired dimensions, but when cutting long materials. Circular saw cutting machines are widely used.

Usually, this type of circular saw cutting machine is provided with two drive systems, a circular saw drive system and a saw blade feed system, and the circular saw drive system changes the rotation of the drive motor to a predetermined number of revolutions. Then, while transmitting this to a circular saw to drive it in rotation, the saw blade feed system operates a drive cylinder or the like by supplying hydraulic pressure to feed the saw blade into the material to cut the material. For the blade feed mechanism, a method was used in which the material was cut from end to end at a preset constant speed.

[0004]

[Problems to be solved by the device]

 By the way, considering the saw blade feed speed when cutting a material having a large hollow part, that is, a steel pipe with a circular saw cutting machine, when cutting a steel pipe, as shown in FIG. When the tip of the saw blade reaches the B position or C position of the steel pipe 4, the effective cutting length of the saw blade becomes maximum, and the load acting on the saw blade at that time becomes maximum, and the maximum load causes the entire saw blade to cut. The blade feed speed is regulated.

On the other hand, between the B position and the C position of the steel pipe 4, the effective cutting length is smaller than that at the B position or the C position, and the load acting on the saw blade is also less than that at the B position or the C position. As a result, the saw blade can be fed at a speed close to twice the saw blade feeding speed at the B position or C position.

However, in a conventional circular saw cutting machine, such a point is not taken into consideration at all, and a method of feeding a saw blade at a constant speed set in advance is adopted, so that Even between positions C, cutting was performed at a slow feed rate regulated at positions B or C.

As a result, even when cutting a steel pipe that is a hollow material, if the outer diameter is the same, the cutting time is not much different from that of a solid material such as a round bar, and the cutting rate (cm ² / min) In other words, there is a problem that the cutting ability, which indicates how many square centimeters can be cut in one minute, is significantly worse than that of a solid material such as a round bar.

[0008] In view of such problems, an object of the present invention is to provide a circular saw cutting machine capable of efficiently cutting a steel pipe.

[0009]

[Means for Solving the Problems]

 Therefore, the circular saw cutting machine for steel pipes according to the present invention is a "circular saw cutting device for steel pipe cutting, in which a circular saw is rotated by a circular saw rotating mechanism and the circular saw is fed to the steel pipe by a saw blade feeding mechanism to cut the steel pipe. Machine, a low-speed drive mechanism that drives the saw blade feed mechanism at a low speed, a high-speed drive mechanism that drives the saw blade feed mechanism at a high speed, and a high-speed drive mechanism in the cutting area where the saw blade load is less than a predetermined load It is equipped with a control circuit that operates the low-speed drive mechanism in the above disconnection region. "

Here, the circular saw feed speed may be switched by detecting the load current of the circular saw drive motor during cutting, or by detecting the actual cutting position with a limit switch and switching at the set position. Alternatively, the timer may detect the elapsed disconnection time and switch to the set time. The control circuit can be composed of a microcomputer and a sequencer. Further, the high speed drive mechanism may be configured by utilizing the low speed drive mechanism as shown in the following embodiments, or may be configured separately from the low speed drive mechanism.

[0011]

[Action]

 In the present invention, the saw blade is fed at a high speed in the cutting area where the load is equal to or lower than the predetermined load, and the saw blade is fed at a low speed in the cutting area where the load is higher than the predetermined load. The saw blade is fed at an optimum speed according to the above, and the steel pipe is cut efficiently.

[0012]

【Example】

 Hereinafter, the present invention will be described in detail based on specific examples shown in the drawings. FIG. 1 shows a circular saw cutting machine for cutting a steel pipe according to an embodiment of the present invention. In the figure, a movable table 2 is slidably provided on a work table 1, a rotary shaft 30 of a circular saw 3 is rotatably supported on the movable table 2, and the work table 1 should be cut. A hydraulic cylinder type clamping mechanism 5 for clamping the steel pipe 4 is provided.

Further, the work table 1 is provided with a rotating mechanism 6 for rotating the circular saw 3. In the rotating mechanism 6, a movable gear 2 (not shown) is provided in the movable table 2, the input shaft of the variable gear group is connected to the rotary shaft of the drive motor 60, and the output of the variable gear group is It is connected to the rotary shaft 30 of the circular saw 3.

Further, a saw blade feeding hydraulic cylinder (saw blade feeding mechanism) 7 is attached to the work table 1, and a piston rod 70 of the hydraulic cylinder 7 is connected to the movable table 2 in this manner. The circular saw 3 is sent to the steel pipe 4 by the extension of the piston 70 of 7 to cut the steel pipe 4.

Further, one end of the hydraulic pressure supply passage 80 is connected to one hydraulic chamber 71 of the hydraulic cylinder 7, and one end of the hydraulic return passage 81 is connected to the other hydraulic chamber 72. And the other end of the hydraulic pressure recirculation passage 81 is connected to the connection ports a and b of the first solenoid valve 82, respectively, and the hydraulic pressure reaching the oil tank T and the hydraulic pump P is connected to the connection ports t and p of the first solenoid valve 82. The aisle is connected. Further, hydraulic throttle valves 83 and 84 with check valves for setting the supply hydraulic pressure are provided in the middle of the hydraulic pressure supply passage 80 and the hydraulic pressure return passage 81, and the hydraulic pressure return passage 81 is provided downstream of the hydraulic throttle valve 84. A drain valve 85 is interposed, and a low-speed drive mechanism 86 that supplies a low hydraulic pressure to the hydraulic cylinder 7 that is a saw blade feed mechanism and drives it at a low speed is configured as described above.

Further, a bypass passage 87 is connected to the hydraulic supply passage 80 by bypassing the hydraulic throttle valve 83, and a second solenoid valve 88 is provided in the bypass passage 87, and an upstream side thereof is provided. Is provided with a hydraulic throttle valve 89, and thus a high-speed drive mechanism 810 for driving the hydraulic cylinder 7 at high speed by supplying hydraulic pressure to the hydraulic cylinder 7 in addition to the hydraulic pressure from the hydraulic pressure supply passage 80 is configured. .. The check valve 811 allows oil to freely pass in the direction opposite to the throttle direction of the hydraulic passages 80 and 81.

In the figure, 90 is a saw blade load sensor that detects the load current of the drive motor 60, and 91 is a signal from the saw blade load sensor 90, and the operation of the first and second solenoid valves 82 and 88 is performed. The control circuit 91 controls the low speed drive mechanism 86 and the high speed drive mechanism 810 by operating the first and second solenoid valves 82 and 88 in the cutting region where the saw blade load is below a predetermined value. On the other hand, the second solenoid valve 88 is stopped in a disconnection region of a predetermined load or more, and only the first solenoid valve 82 is operated to operate the low speed drive mechanism 86.

Next, the function and effect will be described.

In the circular saw cutting machine of the present embodiment, the saw blade load during cutting is checked by the motor current value, and when the preset current value or more is fed at low speed, below the set value is automatically fed at high speed. A saw blade feed mechanism 7 having selectable mechanisms 86 and 810 is provided, and the feed mechanism 810 and 86 of two high-speed and low-speed systems are composed of a hydraulic circuit as shown in FIG.

Now, the saw blade feeding operation will be described. When the forward movement of the circular saw 3 is started, the saw blade is fed at high speed until the motor current reaches the set value 15A. When the saw blade reaches the outer peripheral surface A of the steel pipe 4, the cutting is started, the steel pipe 4 is cut along with the feeding, and the effective cutting length is gradually increased accordingly. It increases as shown in b). When the tip of the saw blade reaches the position before the position B of the steel pipe 4, the motor current value exceeds the set value 15A, so the feed of the saw blade is switched to the low speed feed, and the vicinity of the B portion is cut at low speed.

When the tip of the saw blade exceeds the position B of the steel pipe 4, the effective cutting length gradually decreases and the motor current value also decreases as shown in FIG. 3 (b). The hollow portion between B and C of the steel pipe 4 is cut to the position before the C position.

When the tip of the saw blade reaches the position before the C position of the steel pipe 4, the motor current value increases again as shown in FIG. 3B, so the saw blade feed is switched to the low speed and the steel pipe 4 When cutting the vicinity of C part at a low speed and before reaching the D position of the steel pipe 4, the motor current becomes less than the set value, so the feed of the saw blade is switched to the high speed again and the steel pipe 4 is cut to the D position. finish.

Next, the operation will be described in detail. When the cutting machine is started, first, the drive motor 60 is operated, and its rotation is transmitted to the rotary shaft 30 of the circular saw 3 by changing the rotation speed thereof to a predetermined number of rotations by the speed change gear group. It is rotationally driven at the number of revolutions, and at the same time, the hydraulic pump P is started. At that time, the current of the drive motor 60 is detected by the saw blade load sensor 90, and the detection signal is input to the control circuit 91 to determine whether or not the set value is 15 A or more.

In the region where the motor current is below the set value, the control circuit 91 opens both the first and second solenoid valves 82 and 88. Then, oil is fed from the hydraulic pump P to the hydraulic pressure supply passage 80, adjusted to a predetermined pressure by the hydraulic throttle valve 83 and supplied to the hydraulic chamber 71 of the hydraulic cylinder 7, and one of the oil in the hydraulic pressure supply passage 80 is supplied. The portion circulates in the bypass passage 87, is adjusted to a predetermined pressure by the hydraulic throttle valve 89 and is also supplied to the hydraulic chamber 71 of the hydraulic cylinder 7, and the piston 70 of the hydraulic cylinder 7 advances at high speed.

Further, as the piston 70 advances, the oil in the hydraulic chamber 72 is returned to the hydraulic tank T via the check valve 811 of the throttle valve 84, the hydraulic return passage 81 and the first solenoid valve 82, thus driving at low speed. By operating the high speed drive mechanism 810 in addition to the mechanism 86, the piston 70 of the hydraulic cylinder 7 advances at high speed, and the saw blade is advanced at high speed.

On the other hand, in the region where the motor current is equal to or higher than the set value, the control circuit 91 closes the second solenoid valve 88, stops the hydraulic pressure supply from the bypass passage 87, and the hydraulic chamber 71 of the hydraulic piston 7 is closed. The hydraulic pressure is supplied only from the hydraulic pressure supply passage 81, that is, only the low speed drive mechanism 86 operates, so that the piston 70 of the hydraulic cylinder 7 advances at a low speed and the saw blade moves at a low speed.

In the circular saw cutting machine for steel pipe cutting according to the present embodiment as described above, the magnitude of the saw blade load is determined by detecting the current of the drive motor 60. When the load is large, the load is low, and when the load is small, the load is high. Since the saw blade is fed, it is possible to efficiently cut the steel pipe 4, which has a large saw blade load fluctuation during cutting, and to significantly reduce the actual cutting time.

The inventors of the present invention actually manufactured a variable-feed cutting machine according to the present invention and compared the effect with a conventional constant-speed cutting machine. A 163φ × 123φ bearing steel pipe was used as the material to be cut, and a 570φ × 5.7t segment saw was used as the circular saw. The relation between the cutting position of the steel pipe 4 and the motor current value and the feed rate in the conventional cutting machine and the cutting machine of the present invention is shown in FIGS. 3 (a) and 3 (b). In the conventional cutting machine, the saw blade feed rate is 1.81 mm / sec and the cutting time is 90 seconds, whereas in the cutting machine of the present invention, the low saw blade feed rate is 1.81 mm / sec, high speed. At a feed rate of 3.40 mm / sec and a cutting time of 60 seconds, it was possible to obtain a cutting capacity 1.5 times that of a conventional constant speed cutting machine.

By the way, as a variable feed method, a method of increasing or decreasing the saw blade feed speed in proportion to the magnitude of the saw blade load can be considered, but in such a method, the control system of the cutting machine becomes complicated and the cost height is increased. However, in the circular saw cutting machine of the present embodiment, a bypass passage 87 for supplying hydraulic pressure is provided to switch the feed of the saw blade between high speed and low speed. Is easy and does not cost much.

In the above embodiment, switching between high-speed feed and low-speed feed is performed based on the detection of the motor current value. However, limit switches are provided at positions B and C of the steel pipe 4 so that the steel pipe 4 has an A-B position. It is also possible to switch between low speed feed, low speed feed between B and C, and low speed feed between C and D. Further, a timer may be used to measure the time from the start of the forward movement of the saw blade, and the high speed feed and the low speed feed of the saw blade may be switched at the set time.

[0031]

[Effect of the device]

 As described above, according to the circular saw cutting machine for cutting a steel pipe according to the present invention, the circular saw is rotated by the circular saw rotating mechanism, and the circular saw is fed to the steel pipe by the saw blade feeding mechanism to move the steel pipe. When cutting, high-speed feed is performed in the cutting area where the saw blade load is less than the prescribed load, and low-speed feeding is performed in the cutting area where the saw blade load is greater than the prescribed load, so there is no increase in cost or complication of the control system. , Has the effect of efficiently cutting steel pipes.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a circular saw cutting machine for cutting a steel pipe according to an embodiment of the present invention.

FIG. 2 is a diagram showing a cutting position of a steel pipe for explaining a problem to be solved by the invention.

FIG. 3 is a diagram showing a relationship between a cutting position of a steel pipe and a drive motor current value and a feed rate in a conventional example and a present example.

[Explanation of symbols]

 3 circular saw 4 steel pipe 6 circular saw drive mechanism 7 hydraulic cylinder (saw blade feed mechanism) 86 low speed drive mechanism 810 high speed drive mechanism 91 control circuit

Claims (1)

[Scope of utility model registration request] 1. A circular saw rotating mechanism (6) rotates the circular saw (3) and a saw blade feed mechanism (7) moves the circular saw (3) into a steel pipe (4).
In the circular saw cutting machine for feeding the steel pipe 4 and cutting the steel pipe 4, a low speed drive mechanism 86 for driving the saw blade feed mechanism 7 at a low speed.
And a high speed drive mechanism 810 for driving the saw blade feed mechanism 7 at high speed.
And the high-speed drive mechanism 8 in the cutting area where the saw blade load is less than the predetermined load.
A circular saw cutting machine for cutting a steel pipe, characterized in that 10 is provided with a control circuit 91 for operating the low speed drive mechanism 86 in a cutting region of a predetermined load or more.