JPS63260607A - Device for balancing inertia force of pilger mill - Google Patents

Abstract

PURPOSE:To miniaturize the facility by jointly installing two Pilger mill stands mutually having an equal weight so that they reciprocate in horizontal, opposite directions to each other at the same speed and putting an inertia force balancing device using potential energy between the two stands. CONSTITUTION:A Pilger mill stand 10 provided with a couple of Pilger mill rolls 11 and a Pilger mill stand 12 having the same weight as that of the stand 10 are jointly installed so that the stands 10, 12 interlock and reciprocate in opposite directions to each other at an equal speed. At the time of reciprocating the 1st stand 10 by a motor 15, the 2nd stand 12 reversely reciprocates through racks 17 and pinions 18; generated reciprocative inertia forces are balanced by an inertia force balancing device. The device is composed of coil spring, etc., so that the device stores the kinetic energy of the stands 10, 12 as a potential energy and detects the energy. Reaction force of the coil spring is internally closed in the 1st and 2nd stands 10, 12 and no vibration is propagated to peripheral devices, so that the safety operation is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inertial force balance device for a Birger rolling mill for manufacturing seamless steel pipes and the like.

[Conventional technology and its problems]

In general, a Birger type rolling mill equipped with Birger mill rolls uses a special caliber roll to roll a blank tube between a pair of Birger mill rolls and a mandrel rod, as shown in Japanese Patent Publication No. 51-43472. to produce seamless steel pipes. Its configuration and operation are as follows:
Shown below. That is, to explain with a schematic diagram of a conventional Birger type rolling mill put into practical use in -C, a crank arm 3 and a fan-shaped balancer 4 are fixed to a crankshaft 2 rotated by a main motor. A connecting rod 5 and (1) a connecting rod 6 for a balancer are respectively connected to the connecting rod 3, and a pair of bilger mill rolls 7.7 are provided at the tip of the connecting rod 5.

- The mill stand 8 is connected, and a V-balancer 6'' is suspended from the tip of the above-mentioned balancer connecting rod 6.

When the main motor rotates the crankshaft 2 at a constant rotational speed ω, the bilger mill stand 8 reciprocates via the crank arm 3 and stove throat 5. Along with the reciprocating movement, the bilger mill roll 7 is rotated by a rack and a binion (not shown), and rolls the raw pipe. More specifically, when the bilger mill roll 7 rotates and the raw tube into which the mandrel rod is inserted moves forward while rotating, the bilger mill roll 7 bites into the raw tube. As the Birger mill rolls 7 further rotate, the raw tube is rolled to the finished size, and then the raw tube is removed from contact with the Birger mill rolls 7. On the other hand, the raw tube is stopped while being rolled by the Birger mill rolls 7, but as soon as the raw tube is freed from the Luger mill rolls 7, it moves forward.

As described above, the conventional Birger rolling mill that has been put into practical use uses a crank mechanism to reciprocate the Birger mill stand 8 equipped with the Birger mill rolls 7 with great force. An unbalance occurs due to the inertial force of the reciprocating motion and the couple due to the inertial force, but in order to eliminate this unbalance,
As mentioned above, the fan-shaped balancer 4 and the square balancer 6' are provided.

However, in this Birger type rolling mill, the following disadvantages arise due to the provision of the fan-shaped balancer 4 and the V-balancer 6'. Namely, 1) the Jfi type balancer 4 and the balancer 6' are provided, which increases the size. 2) In the fan-shaped balancer 4 and the V-balancer 6°, the unbalance of the first-order term (the first-order term in the well-known general formula expressing reciprocating inertia force; the same applies hereinafter) based on the rotational speed ω of the crankshaft 2 is It can be eliminated, but
The unbalance of higher-order terms cannot be eliminated. Therefore, in order to reduce the unbalance of higher-order terms, the ratio between the length R of the crank arm 3 and the length of the connecting rod 5 must be reduced. , the length of the connecting rod 5 increases, and the entire device becomes larger. 3) ■ Balancer 6°
Therefore, for example, a pilger mill rolling mill for cold-rolling a 2601 mm diameter mother pipe requires foundation work approximately 8 m deep, which in turn makes maintenance around the 6° balancer difficult.

On the other hand, in Japanese Patent Publication No. 51-43992, a rough rolling bilger mill stand and an intermediate/finish rolling bilger mill stand, which are driven by a main motor via a crank mechanism, are installed in series. A Birger-type rolling mill is introduced in which stands are linked by racks and binions, and the stands are reciprocated in opposite directions.

However, in such a Birger type rolling mill, the main motor drives the rough rolling Birger mill stand via one connecting rod, and the intermediate and finishing Birger mill stands drive the Birger mill stand for intermediate and finishing rolling.
Since the rough rolling bilger mill stand is interlocked with the rack and the pinion, double the inertia force acts on the connecting rod in the crank mechanism, which may cause damage to the crank pin, etc. Moreover, the reciprocating inertia force A balance device is not disclosed.

[Means for solving problems]

Therefore, the present invention was created with a focus on completely solving the problems of the prior art described above, and its gist is to rotate a Birger mill stand equipped with a pair of Birger mill rolls. In an inertial force balance device for a Birger rolling mill that reciprocates horizontally using power converted from motion to reciprocating motion, two of the Birger mill stands are provided.
In addition to interlocking and connecting objects of the same importance so that they move back and forth in opposite directions and at the same speed, these two
This is an inertial force balance device for a Birger type rolling mill, in which an inertia force balance device for balancing the inertia of the Birger mill stands is interposed between each Birger mill stand, and is equipped with potential energy such as a spring or an air cylinder.

[Basic Control of Embodiment] The configuration and operation of this embodiment will be explained in detail with reference to the first and second embodiments shown in the accompanying drawings.

This embodiment is suitable for a so-called large-sized Birger rolling mill that cold-rolls a seamless steel pipe with a diameter of 260+-, for example, and generates about 59 tons of reciprocating inertia force.

In FIG. 1 showing the first embodiment, 10 is a first roll stand (Bilger mill stand) equipped with a pair of bilger mill rolls 11, 11 for intermediate and finishing rolling, and 12 is a pair of rough rolling and balance weights. A second roll stand (Birger mill stand) is shown with Birger mill rolls 13.13 for the first roll stand 10 and the second
The weight is the same as that of the roll stand 12.

14 is an inertia force balance device that balances the inertia force caused by the reciprocating motion of both roll stands 10 and 12. The one shown is a coil spring type, but the piston rond is placed on the first roll stand 10, and the cylinder is placed on the second roll stand 10. A single type of air cylinder connected to each roll stand may be used, and any type having potential energy such as spring force or air compression force may be used, such as the type already filed by the present applicant.

Reference numeral 15 denotes a main motor, which reciprocates the first roll stand 10 via the crankshaft 2, crank arm 3, and connecting rod 5.

A rack 17 and a pinion 18 are interposed between the first roll stand 10 and the second roll stand 12 in a pair, upper and lower, to interlock both roll stands 1o and 12.

That is, the second roll stand 12 is fixed to a U-shaped frame 19, and ranks 17.17 are carved in opposing positions of the U-shaped frame 19. On the other hand, racks 17a, 17a are carved on the upper and lower outer sides of the first roll stand 10, and a pinion 18 is engaged between these racks 17, 17a. Since the axis position of the pinion is fixed during the day, the reciprocating motion of the first roll stand 10 and the second roll stand I2 is the same speed in opposite directions on the floor surface. It moves with the same amount of displacement.

20 is a tacho generator and rotation angle detector (T, G)
, 21 is an inertia force balance calculation unit which detects the rotational speed ω of the crankshaft 20 by T, 0.20, and the inertia force balance calculation unit 21 adjusts the inertia force balance device 14 so that the inertia force balance is at an optimum value. command to.

FIG. 2 is a side sectional view showing the relationship between the bilger mill roll 11.13, the mandrel rod 22, and the raw tube 23;
3 move in opposite directions to each other as described above, and the base pipe 2
3. When moving in the direction of the arrow A, the blank tube 23 is rolled by both pilger mill rolls 11 and 13. On the other hand, the mandrel rod 22 is composed of a common rod of both bilger mill rolls 11 and 13, and
It is configured into two stages 22a and 22b according to the rolling area of No. 3.

Next, the principle of controlling the inertial force balance device 14 is as follows. That is, in this embodiment, control is aimed at focusing on the point that the first-order term of the inertia force of reciprocating motion can be well balanced with the spring force of the coil spring, and moreover, depending on the rotational speed ω of the crankshaft 2, This aims to optimize the spring constant of a coil spring. Therefore, regarding the first roll stand 10, the crankshaft 2
When the rotational speed ω of is constant, the first-order term of the reciprocating inertia of the first roll stand 10 is expressed as the inertia force balance li
Since it is sufficient to balance the balance with the spring force of the coil spring 14, M: Weight of the first roll stand lO ￥ Heaven = Acceleration of the displacement X of the first roll stand lO = Spring constant of the spring of the inertia force balance device 14 Then, Mken-k (2x) ...■.

On the other hand, the Hane constant is determined as follows. That is,
In this example, only the first-order term of the reciprocating inertia of the crank motion was balanced by the coil spring and the higher-order terms were ignored. Therefore, the well-known general formula expressing the reciprocating inertia is R/L (
If it is 1, then x-1-ω ×x...
(2) is obtained, and k = -Mo2 . . . (2) is obtained from these equations (2) and 0. By appropriately selecting the spring constant k according to the rotational speed ω, most of the reciprocating inertia of the first roll stand 10 can be balanced. In addition, when the coil spring is divided and a common base etc. is intervened in the middle, the formula 0 becomes = M
It becomes ω2.

Further, the reciprocating inertia force of the second roll stand 12 is similarly balanced by the inertia force balance device I4.

Since this embodiment adopts the configuration described above, its operation is as follows. That is, when the first roll stand 10 is reciprocated by the main motor 15 via the stove throat 5 or the like, the second roll stand 12 is reciprocated in the opposite direction via the rank pinion 17,18. At this time, the reciprocating inertia force generated from the 18th and second roll stands 10.12 is the inertia force balance EaVt 14
Balance at. Since the inertial force balance device 14 is composed of, for example, a coil spring, it stores the kinetic energy of the first and twentieth stands 10.12 as potential energy of the coil spring, and releases it. The reaction force of the coil springs is therefore internally closed in the first and second roll stands 10.12.

Further, the rotational speed ω of the crankshaft 2 is detected at T, 0.20, and the inertia force balance calculating section 21 sets the coil spring constant k to the optimum value of the inertia force balance.

Then, the raw tube 23 and the mandrel rod 22 are fed to the bilger mill rolls 13.13 for rough rolling while being given appropriate feed and rotation, and when moving in the flow direction of the raw tube 23, the raw tube 23 is Mill roll 13.13
and a mandrel rod 22a, and further rolled by a bilger mill roll 11.11 for finishing or intermediate rolling and a mandrel rod 22b.

Next, a second embodiment of the present invention will be described. In FIG. 3, only the parts that are different from the first roll stand will be described. The second roll stand 12 is constituted by a box-shaped frame 24, and the first roll stand 10 is reciprocated within the knot-shaped frame 24. These first and second roll stands 10.12 are reciprocated by stove throats 5 and 5a connected by the same crankshaft 2 with a 180' phase difference.

Therefore, the second embodiment does not require a rack and pinion.

In summary, since the present invention adopts the configuration described in the claims, the various effects listed below can be expected.

〔Effect of the invention〕

■Compared to the conventional Pilga rolling mill equipped with ■balancers and fan-shaped balancers, the effect of eliminating unbalance is the same (however, it can be reduced by 20%), but since these balancers have been replaced with rough rolling roll stands, the Miniaturization of the drive unit that converts dynamic motion to reciprocating motion, and increased speed (for example,
It is possible to increase the speed of ω by 1.5 times), ease of maintenance, and simplify foundation work.
Energy savings are achieved by balancing the unbalanced force induced by the reciprocating motion of the Birger mill stand with the potential energy of the inertial force balance device. In other words, for example, in a large pilger rolling mill, the inertial force reaches up to 60 tons, so a lot of external energy is required to balance the inertial force, but this external force can be absorbed by the inertial force balance device. is covered by potential energy. Of course, the continuous bilger mill stand increases the rolling reduction rate and further improves productivity.

■ Since the inertial force is balanced by the potential energy of the inertial force balance device, it can be installed in combination with a Pilga rolling mill equipped with a conventional fan-shaped balancer and V-balancer. can be converted into

■ According to the present invention, inertial force is balanced by the potential energy of the inertial force balance device, so there is no need for connecting rods, crank arms, crankshafts, etc. that require machining to receive excessive force, and there is no need to increase the size. , miniaturization and cost reduction can be achieved.

■ The potential energy that balances the inertial force of one Birger mill stand and the potential energy that balances the inertial force of the other Birger mill stand cancel each other out on the common floor and are closed internally, so the surrounding Vibration is not transmitted to equipment, etc., ensuring operational safety.

■ An inertial force balance device equipped with potential energy, such as a spring or an air cylinder, is interposed between the two Birger mill stands, so the device that drives the Birger mill stands and converts rotational motion into reciprocating motion is Can be made smaller.

(2) Incidentally, FIG. 5 shows a comparison example between the Birger type rolling mill equipped with an inertial force balance device using =Mω2 according to the embodiment of the present invention and the conventional example shown in FIG. 4.

That is, in FIG. 5, L=4000mn+, R=72
The test was conducted at 0 mm and M' = 35 tons, and the graph shows the amount of inertial force imbalance, with force (ton) on the vertical axis and time (seconds) on the horizontal axis. The same figure (a) is ω=
In the case of 45 rpm, k=400kg/cmX2set (both sides), (b) figure is ω=3 Orpm, k=
The case of 178 kg/cm x 2 sets (both sides) is shown. The broken line indicates the inertia force balance oil in the conventional example shown in FIG. 4, and the solid line indicates the inertia force unbalance amount in the present embodiment.

As is clear from the figure, in this embodiment, the unbalance is always kept small.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an embodiment of the present invention, Fig. 2 is a detailed view of the main part of Fig. 1, Fig. 3 is a schematic diagram of the second embodiment, and Fig. 4 is a schematic diagram of a conventional example. Figure 5 shows a graph of the test example. 2... Crankshaft, 3... Crank arm, 5...
・Connecting rod, 10...first roll stand, 11
．． 13... Birger mill roll, 12... Second roll stand, 14... Inertial force balance device, 17.
...Rack, 18...pinion.

Claims (1)

[Scope of Claim] In an inertial force balance device for a Birger type rolling mill, which horizontally reciprocates a Birger mill stand equipped with a pair of Birger mill rolls using power converted from rotary motion to reciprocating interlocking motion, the Birger mill stand is provided with: Two pieces of the same weight are interlocked and connected so that they reciprocate in opposite directions and at the same speed, and potential energy such as a spring or air cylinder is applied between these two bilger mill stands. An inertia force balance device for a Birger type rolling mill that is equipped with an inertia force balance device that balances the inertia force of a Birger mill stand.