JPS6358048B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a strip rolling mill.

(Prior Art) A strip is a metal, a non-metal, or a composite thereof, and herein refers to a rollable band-like body of these metals.

Strips are mainly manufactured by being stretched using rolling mills. When manufacturing the strip by rolling, it is desirable to use small-diameter work rolls to achieve a large rolling reduction and to reduce the number of passes. Especially when producing ultra-thin strips,
The smaller the work roll diameter, the fewer passes can be made.

When using small-diameter work rolls, a back-up roll is required because the rolls are deflected by the rolling force. The conventionally known Sendzimir rolling mill is
It is the most commonly used rolling mill for ultra-thin strips, and has a complex structure in which two work rolls are supported by 18 back-up rolls.
The dimensional relationship between the work roll and the back-up rolls is subject to geometrical constraints, and in order to reduce the work roll diameter, the number of back-up rolls must be increased arithmetically.

As the number of stages of the back-up rolls increases, the amount of elastic deformation of the rolls accumulates, resulting in poor plate thickness accuracy and plate shape. In addition, the Sendzimir rolling mill has a complex structure, is expensive, and requires advanced technology to operate. U.S. Patent No. 2710550, U.S. Patent No. 2811060,
Each publication of British Patent No. 609706 shows a dual-drive planetary rolling mill, but since this rolling mill uses intermittent rolling in which the work rolls circulate, it produces significant noise and the strength of the work rolls is low. It was weak and had many breakdowns.

Japanese Unexamined Patent Publication No. 58-35003 discloses that one of the upper and lower work rolls is made smaller in diameter than the other work roll, and the small diameter work roll is offset in the rolling direction with respect to the other work roll.
A rolling mill is shown in which a presser roll, a dividing roll, and a horizontal bending device are arranged parallel to the small-diameter work roll on the offset side of the small-diameter work roll.

Since the purpose of this rolling mill is to control the plate thickness, it is offset to the exit side for small diameter work rolls, and for small diameter work rolls, a rolling component force is generated toward the exit side, It is received by the position control device on the exit side.

In such a rolling mill, the position of the small-diameter work roll fluctuates back and forth due to fluctuations in rolling load, making it difficult to make the small-diameter work roll an extremely small diameter.
In particular, this drawback is exacerbated in reciprocating rolling or so-called mixed peripheral speed rolling in which the circumferential speeds of upper and lower work rolls are different, making it difficult to improve plate thickness accuracy and plate shape.

(Objective of the Invention) An object of the present invention is to provide a strip rolling mill that holds small-diameter work rolls and enables high-rigidity rolling and high-reduction rolling both in a reciprocating manner.

(Structure and operation of the invention) The present invention arranges two work rolls separated by a strip for one driving work roll,
In a rolling mill that rolls the strip at two locations,
This strip rolling mill is constructed so that a work roll of the smallest diameter is supported by its back up roll and the work roll.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 shows a rolling mill according to the present invention, in which two work rolls 2 and 3 are arranged with a strip 5 separated from one drive work roll 1. One work roll 2 has a small diameter to the extent that it requires a back-up roll 4, and this small-diameter work roll 2 is also supported by the adjacent work roll 3 and held firmly.

Since the small-diameter work roll 2 is driven to rotate by the rolling force, there is no need to drive it. This small diameter work roll 2 is in contact with the drive work roll 3, and both rolls are moving in opposite directions at the contact position,
Frictional force is generated in the direction of mutually restraining rotation.

Frictional force is generally expressed as the product of the friction coefficient and the force acting perpendicularly to the roll surface. The coefficient of friction on the surface of the small diameter work roll 2 is considerably larger at the position where the strip is deformed than at the position where it contacts the work roll 3, and the force acting on the surface of the work roll 2 is also greater at the position where the strip is in contact with the strip. Since the frictional force is selected to be large, the frictional force will be much larger at the strip contact position than on the work roll 3 side, and the non-driven small diameter work roll 2 will follow the strip.

The contact force between the non-driven small-diameter work roll 2 and the driven work roll 3 is desirably the minimum value in order to prevent the small-diameter work roll from deflecting. On the other hand, the contact force between the non-driven small diameter work roll 2 and the strip is
It is desirable to make it large enough to significantly reduce the wall thickness of the strip.

That is, in FIG. 2, work rolls 1,
2, 3, the center of the backup roll 4 is P ₁ , P ₂ , P ₃ , P ₄ , and the radius is R ₁ , R ₂ , respectively.
The thickness of the strip between R ₃ , R ₄ , P ₁ and P ₂ is t ₁ ,
Let the thickness of the strip between P ₁ and P ₃ be t ₂ . Since the roll deformation is negligibly small, P ₂ and
When the extension of the straight line passing through P ₄ passes through P ₁ , the vector component force toward work roll 1 becomes maximum, but the vector component force toward work roll 3 becomes 0, and work roll 2 is supported by work roll 3. Power disappears.

Also, when the extension of the straight line passing through P ₂ and P ₄ passes through the half point Q of <P ₁ P ₂ P ₃ , the force from work roll 2 towards the strip and the force towards work roll 3 are equal. If the friction coefficients between the two were equal, the rotational direction of the work roll 2 would become unstable, but in reality the friction coefficient at the position where it contacts the strip is greater than at the position where it contacts the drive roll. The rotation of the work roll 2 coincides to a large extent with the direction of movement of the strip.

However, in order to guarantee stable rolling at all times, it is desirable that the extension of the straight line passing through P ₂ and P ₄ be between P ₁ and Q.

(Effects of the Invention) As described above, by holding a small-diameter work roll with two large-diameter work rolls, the diameter of the small-diameter work roll can be significantly reduced. Generally, the influence of work roll diameter on rolling characteristics is as follows:
Work roll diameters D ₁ and D ₂ on both sides of the rolled material
Then, the equivalent roll diameter (=2D ₁ D ₂ / (D ₁ +
_D2 )) is discussed as an indicator, and by reducing the diameter of one of the work rolls, the equivalent roll diameter can be significantly reduced, the rolling load and rolling torque will be reduced, and high rolling reduction will be possible. .

For example, if D ₂ is set to 1/5 or 1/10 of D ₁ , the equivalent roll diameter becomes as small as 0.33D ₁ or 0.18D ₁ , respectively. In addition, since the small diameter work rolls of the roll set shown in Figure 1 are not driven, they can be easily stored in the housing of a conventional double rolling mill or quadruple rolling mill, and can be used in conventional rolling mills. Therefore, it becomes an inexpensive rolling mill.

In addition, small-diameter work rolls are supported by large-diameter back-up rolls from the direction opposite to the rolling force, so their rigidity can be significantly increased, and as in the Sendzimir rolling mill, elastic deformation of the rolls accumulates, resulting in sheet thickness accuracy. There is no possibility that the shape of the plate will deteriorate. Furthermore, small-diameter work rolls are not limited by geometrical size and are freed from limitations on torsional and bending rigidity, so they can be significantly smaller in diameter and can be operated under high pressure.

This rolling mill has one-side roll drive, different diameter roll rolling,
Alternatively, the industrial effect is great, such as being able to obtain effects such as rolling at different circumferential speeds.

[Brief explanation of the drawing]

FIG. 1 is a side view of the apparatus of the rolling mill of the present invention, and FIG. 2 is an explanatory view of the operation of the rolling mill of the present invention. 1, 3: Large diameter work roll, 2: Small diameter work roll, 4: Backup roll, 5: Strip.

Claims (1)

[Claims] 1. In a rolling mill in which two work rolls are arranged with a strip separated from one drive work roll and the strip is rolled at two locations, the work roll with the smallest diameter is A strip rolling mill characterized in that it is configured to be supported by a back up roll and the work roll. 2 The angle A between the center of the non-driven work roll with the smallest diameter and the center of the other two work rolls is 2
When dividing the inside of the corner into two areas, the extension of the straight line connecting the center of the work roll with the smallest diameter and the center of the back-up roll of the roll is the workpiece on the side that separates the work roll with the largest diameter from the strip. A strip rolling mill according to claim 1, characterized in that the strip rolling mill is constructed in such a way that the roll centers are connected together.