JPH039842Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an inertial force balance device for a Pilger type rolling mill that manufactures seamless steel pipes and the like.

[Conventional technology and its problems]

Generally, the Pilger type rolling mill equipped with Pilger mill rolls, which is in practical use, is equipped with a pair of Pilger mill rolls with special calipers, as shown in Japanese Patent Publication No. 51-43472, for example. The raw pipe is rolled between the mandrel rod and a seamless steel pipe is manufactured. Its configuration and operation are as follows:
To explain with the schematic diagram of the conventional example shown in the figure, a crank arm 3 and a fan-shaped balancer 4 are fixed to a crankshaft 2 rotated by a main motor, and a connecting rod 5 and a connecting rod 6 for a V balancer are connected to the crank arm 3, respectively. A pilger mill stand 8 equipped with a pair of pilger mill rolls 7, 7 is connected to the tip of the cooking rod 5, and a V balancer 9 is suspended from the tip of the cooking rod 6 for the V balancer.

Then, the main motor rotates the crankshaft 2 at a rotational speed ω
When rotated at a constant speed, the pilger mill stand 8 reciprocates via the crank arm 3 and connecting rod 5. Along with the reciprocating movement, the pilger mill roll 7 rotates via a rack and pinion (not shown) to roll the raw pipe. To put this further into perspective, when the pilger mill roll 7 rotates and the raw tube into which the mandrel rod is inserted moves forward, the roll 7 bites into the raw tube, and when the roll 7 rotates further, the raw tube has the finished size. The raw tube is then rolled away from the contact of the rolls 7. On the other hand, the raw tube stops while being rolled and in contact with the rolls 7, but as soon as the raw tube is freed from the rolls 7, it moves forward.

As described above, the conventional Pilger type rolling mill that has been put into practical use employs a crank mechanism to reciprocate the Pilger mill stand 8 on which the Pilger mill roll 7 is mounted, with great force. Unbalance occurs due to the inertial force of the reciprocating motion induced by the crank motion and the couple due to the inertial force. In order to eliminate this unbalance, the fan-shaped balancer 4 and V
A balancer 9 is provided.

However, in such a conventional Pilger type rolling mill, since the sector balancer 4 and the V balancer 9 are used for balance, the inertia force of the reciprocating motion is expressed as
Since the quadratic term (referring to the inertial force due to cos 2ω, hereinafter simply referred to as the quadratic term of the inertial force) in the well-known general formula cannot be balanced, originally ω
Since the conrod 5, crankshaft 2, etc. receive a large inertial force proportional to the square of Therefore, there is a limit to how high the speed can be increased, and in order to increase the speed, the ratio between the length R of the crank arm 3 and the length L of the connecting rod 5 must be reduced. The length L becomes longer, and as a result, the entire device becomes larger.

[Means for solving problems]

Therefore, the present invention was created in order to solve the problems of the conventional technology, and in particular, it is aimed at increasing the speed of the commonly used Pilger type rolling mill without changing it as much as possible. The purpose of this invention is to provide an inertial force balance device.

〔Example〕

Hereinafter, the structure of the present invention will be explained in detail with reference to embodiments shown in the accompanying drawings. Note that the same parts as those in the conventional example shown in FIG.

First, a theoretical overview of this embodiment will be described.

In other words, from the well-known general formula expressing the reciprocating inertia force, the horizontal inertia force FH of the reciprocating movement of the Pilger mill stand 8 can be calculated as FH=MRω ² (cos ωt+R /LHcos2ωt) M: Weight of pilger mill stand 8 LH: Length of connecting rod 5 ωt: Represented by crank angle θ.

Here, in this embodiment, as in the prior art, the first-order term MRω ² cos ωt is balanced both horizontally and vertically by the fan-shaped balancer 4, but the second-order term MRω ² ×R/LH×cos2ωt In the horizontal direction, the maximum value at is balanced as MRω ² R/LH=mr(2ω) ² ×2, so that the mass unbalancer mr can be obtained.

That is, by attaching mr=MR ² /8LH to the crankshaft 2, the secondary inertia force in the horizontal direction in the pilger mill stand 8 can be balanced.

Similarly, the vertical unbalancer m′r′ is m′r′=MR ² /8LV LV: The length of connecting rod 6 for V balancer is this
If m'r' is attached to the crankshaft 2, the horizontal secondary inertia force in the pilger mill stand 8 can be balanced.

Therefore, according to this embodiment, since the inertia of the reciprocating motion of the Pilger mill stand 8 can be almost perfectly balanced, it is possible to increase the speed of the Pilger rolling mill, and moreover, stable operation can be achieved even in the high speed range. I can do it.

Next, the structure for mounting the mass unbalancer mr on the crankshaft 2 will be described. That is, the first
2 and 3, the cells 10 and 10' of the horizontal unbalancer mr are attached to one end of the rotating shafts 11 and 12, and these rotating shafts 1
1 and 12 are rotatably supported on a frame 13 through which a crankshaft 2 is inserted. In the figure, a small diameter gear 14 is fixed to the other end of the lower rotating shaft 11,
The small diameter gear 14 is rotated by a first gear 16 fixed to the crankshaft 2 via an idle gear 15. Here, it is assumed that the gear ratio of the first gear 16 and the small diameter gear 14 is 2:1. Further, an intermediate gear 17 is fixed to the other end of the upper rotating shaft 12, and the intermediate gear 17 is fixed to the upper rotating shaft 12.
is rotated by a second gear 18 fixed to the crankshaft 2. Here, the gear ratio between the second gear 18 and the medium gear 17 is 2/1. Therefore, the rotation shafts 11 and 12 rotate in opposite directions at twice the rotational speed of the crankshaft (ω'=2ω).

Also, 10 of the vertical mass unbalancer m′r′
a and 10'a are also attached to the crankshaft 2 in the same way. It should be noted that these are shown with a added to the drawing symbols (for example, 11, 12, . . . ) described above, and therefore their explanation will be omitted.

Further, although this embodiment has been described using a so-called large-sized Pilger type rolling mill, it goes without saying that the present invention is not limited to this.

[Effect of idea]

In summary, since the present invention adopts the structure described in the claims for utility model registration, it has the following effects.

While following the traditional Pilger rolling mill with fan-shaped and V-balancers, it also balances the quadratic term of inertia, expanding the functionality of the rolling mill and making it especially possible to increase speed. Become.

Stable operation is possible even at high speeds, improving the quality of rolled products.

According to the present invention, since the quadratic term is balanced, there is no need for the connecting rod, crank arm, and crankshaft, which are made of high-quality materials and require machining, to receive excessive force, and as a result, there is no need to increase the size. This makes it possible to significantly reduce costs. In addition to this, for example, the foundation bolt of the housing for storing the Pilger mill stand (which is required for any Pilger mill stand) is At least the next term, the inertial force, had to be supported, so as the speed increased, stronger foundation bolts were required. However, according to the present invention, since the quadratic term is also balanced, the foundation bolt only needs to be supported by the rolling horizontal reaction force, and since this rolling horizontal reaction force is almost unrelated to the rotation speed,
Even if the speed is increased, the foundation bolts will not be affected and there is no need to change them.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of an embodiment of the present invention, Figure 2 is an enlarged view of the main part of Figure 1, and Figure 3 is partially omitted from Figure 2.
~A sectional view, FIG. 4 is a schematic diagram of a conventional example. 2... Crankshaft, 4... Fan-shaped balancer, 6...
...V balancer rod, 7...Pilger mill roll, 8...Pilger mill stand, 9...V balancer, 10, 10', 10a, 10a'...mass,
ω...Rotation speed.

Claims (1)

[Claims for Utility Model Registration] A Pilger mill stand equipped with a pair of Pilger mill rolls is reciprocated by a crankshaft, and the primary term of the inertia of the reciprocating motion of the Pilger mill stand is applied to the crankshaft. In an inertial force balance device for a Pilger type rolling mill that balances with an attached fan-shaped balancer and a V-balancer suspended from a connecting rod for the V-balancer, at least four mass unbalancers are installed on each rotating shaft arranged around the crankshaft. At the same time, the crankshaft and the rotating shaft are connected via gears mounted on the respective shafts, and the ratio of the number of teeth of the gear mounted on the crankshaft to that of the gear mounted on the rotating shaft is 2:1. The mass unbalancers, which are located symmetrically across the crankshaft, are rotated in opposite directions at twice the rotational speed of the crankshaft, and the secondary inertia of the reciprocating motion of the Pilger mill stand is An inertial force balance device for a Pilger rolling mill, characterized by balancing the force in both the horizontal and vertical directions. An inertial force balance device for a Pilger rolling mill as claimed in claim 1, wherein four mass unbalancers are mounted on a crankshaft. An inertial force balance device for a Pilger type rolling mill as claimed in claim 1, wherein four mass unbalancers are mounted on a Pilger mill stand and rotated by another drive source.