Tensioning pulley set for a straightening line for straightening a strip, re-rolling stand line and method of operating a straightening line

Abstract

A tensioning pulley set for a straightening machine for straightening a strip or for a re-rolling stand for re-rolling a strip, comprising a first tensioning pulley with a first pulley axis and at least one second tensioning pulley with a second pulley axis, the first tension pulley being a flatness measuring pulley having a force sensor for measuring a radial force applied to the circumferential surface of the flatness measuring pulley, and a drive for the second tensioning pulley with which a torque can be applied thereto on the second pulley axis, either the first tensioning pulley configured without a drive, or an auxiliary drive provided for the first tensioning pulley with which a torque can be applied to the first tensioning pulley on the first pulley axis, the auxiliary drive for the first tensioning pulley being significantly weaker than the drive for the second tensioning pulley.

Claims

1. A tensioning pulley set for a straightening line for straightening a strip or for a re-rolling stand for re-rolling a strip, the tensioning pulley set comprising: a first tensioning pulley having a first pulley axis, the first tensioning pulley being a flatness measuring pulley having a force sensor for measuring a radial force exerted on a circumferential surface of the flatness measuring pulley; and a second tensioning pulley with a second pulley axis, and a drive for the second tensioning pulley with which a torque can be applied to the second tensioning pulley on the second pulley axis; wherein the first tensioning pulley is configured without a drive.

2. The tensioning pulley set according to claim 1, further comprising a third tensioning pulley having a third pulley axis and a fourth tensioning pulley having a fourth pulley axis, wherein: a. a drive is provided for the third tensioning pulley with which a torque can be applied to the third tensioning pulley on the third pulley axis; and/or b. a drive is provided for the fourth tensioning pulley with which a torque can be applied to the fourth tensioning pulley on the fourth pulley axis.

3. The tensioning pulley set according to claim 2, further comprising a fifth tensioning pulley having a fifth pulley axis, wherein a drive for the fifth tensioning pulley is provided by which a torque on the fifth pulley axis can be applied to the fifth tensioning pulley.

4. The tensioning pulley set according to claim 1, wherein the flatness measuring pulley has an axial bore running parallel to the first pulley axis, and wherein the force sensor is arranged in the axial bore.

5. The tensioning pulley set according to claim 4, wherein the flatness measuring pulley has a surface coating.

6. The tensioning pulley set according to claim 1, further comprising a belt guided over the first tensioning pulley and over the second tensioning pulley, the belt wrapping around at least one of: a) the first tensioning pulley with a wrap angle of at least 90, and b) the second tensioning pulley with a wrap angle of at least 90.

7. A straightening unit for straightening a strip, comprising: a front tensioning pulley set; a rear tensioning pulley set; a stretching zone between the front tensioning pulley set and the rear tensioning pulley set; and/or a bending stand between the front tensioning pulley set and the rear tensioning pulley set; wherein the front tensioning pulley set and/or the rear tensioning pulley set comprises: a first tensioning pulley having a first pulley axis, the first tensioning pulley being a flatness measuring pulley having a force sensor for measuring a radial force exerted on a circumferential surface of the flatness measuring pulley; and a second tensioning pulley with a second pulley axis, and a drive for the second tensioning pulley with which a torque can be applied to the second tensioning pulley on the second pulley axis; wherein the first tensioning pulley is configured without a drive.

8. The straightening unit according to claim 7, wherein the rear tensioning pulley set is a tensioning pulley set having a first tensioning pulley with a first pulley axis, a second tensioning pulley with a second pulley axis, a third tensioning pulley with a third pulley axis, and a fourth tensioning pulley with a fourth pulley axis, the first tensioning pulley being the tensioning pulley of the tensioning pulley set on which a belt first runs up; and/or the front tensioning pulley set is a tensioning pulley set having a first tensioning pulley with a first pulley axis, a second tensioning pulley with a second pulley axis, a third tensioning pulley with a third pulley axis, a fourth tensioning pulley with a fourth pulley axis, and wherein the first tensioning pulley is the tensioning pulley of the front tensioning pulley set from which the belt runs off last.

9. The straightening unit according to claim 7, wherein the rear tensioning pulley set is a tensioning pulley set having a first tensioning pulley with a first pulley axis, a second tensioning pulley with a second pulley axis, a third tensioning pulley with a third pulley axis, and a fourth tensioning pulley with a fourth pulley axis, the first tensioning pulley being the tensioning pulley of the tensioning pulley set on which a belt first runs up; and the front tensioning pulley set is a tensioning pulley set having a first tensioning pulley with a first pulley axis, a second tensioning pulley with a second pulley axis, a third tensioning pulley with a third pulley axis, a fourth tensioning pulley with a fourth pulley axis, and wherein the first tensioning pulley is the tensioning pulley of the front tensioning pulley set from which the belt runs off last.

10. A re-rolling stand for the re-rolling of a strip comprising: a. a front tensioning pulley set; b. a rear tensioning pulley set; C. a re-rolling stand provided between the front tensioning pulley set and the rear tensioning pulley set; wherein the front tensioning pulley set and/or the rear tensioning comprises: a first tensioning pulley having a first pulley axis, the first tensioning pulley being a flatness measuring pulley having a force sensor for measuring a radial force exerted on a circumferential surface of the flatness measuring pulley; and a second tensioning pulley with a second pulley axis, and a drive for the second tensioning pulley with which a torque can be applied to the second tensioning pulley on the second pulley axis; wherein the first tensioning pulley is configured without a drive.

11. The re-rolling stand according to claim 10, wherein the front tensioning pulley set is a tensioning pulley set having a first tensioning pulley with a first pulley axis, a second tensioning pulley with a second pulley axis, a third tensioning pulley with a third pulley axis, a fourth tensioning pulley with a fourth pulley axis; and the rear tensioning pulley set is a tensioning pulley set having a first tensioning pulley with a first pulley axis, a second tensioning pulley with a second pulley axis, a third tensioning pulley with a third pulley axis, and a fourth tensioning pulley with a fourth pulley axis.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) In the following, the invention is explained more closely with the aid of drawings showing merely realizations. Shown are:

(2) FIG. 1 a schematic side view of a straightening machine according to the invention;

(3) FIG. 2 a schematic side view of a further straightening system according to the invention, and

(4) FIG. 3 a schematic representation of the forces acting on a measuring pulley.

DETAILED DESCRIPTION

(5) The straightening unit 1 shown in FIG. 1 for straightening a strip 2 has a front tensioning pulley set 3 and a rear tensioning pulley set 4. A bending frame 5 is provided between the front idler set 3 and the rear idler set 4. A reel 6 is provided in front of the front idler set 3. A reel 7 is provided behind the rear idler set 4.

(6) The strip 2 is uncoiled from the reel 6, passes through the front set of tension pulleys 3, passes through the bending stand 5, passes through the rear set of tension pulleys 4 and is coiled up by the reel 7. In the front tensioning pulley set 3, the belt tension acting on the belt 2 is increased, while in the rear tensioning pulley set 4, the belt tension acting on the belt 2 is reduced, so that the belt tension acting on the belt 2 in the area of the bending stand 5 higher than before the front tensioning pulley set 3 and after the rear tensioning pulley set 4.

(7) The rear tensioning pulley set 4 has a first tensioning pulley 8 with a first pulley axis, a second tensioning pulley 9 with a second pulley axis, a third tensioning pulley 10 with a third pulley axis, a fourth tensioning pulley 11 with a fourth pulley axis,

(8) wherein the first tension pulley 8 is a flatness measuring pulley having a force sensor for measuring a radial force (FR,1) applied to the circumferential surface of the flatness measuring pulley.

(9) a drive (not shown in more detail) for the second tensioning pulley 9 is provided, with which a torque can be applied to the second tensioning pulley 9 on the second pulley axis. Furthermore, a drive (also not shown in more detail) is provided for the third tensioning pulley 10, with which a torque can be applied to the third tensioning pulley 10 on the third pulley axis. Furthermore, a drive (also not shown in more detail) is provided for the fourth tensioning pulley 11, with which a torque can be applied to the fourth tensioning pulley 11 on the fourth pulley axis.

(10) The first tensioning pulley 8 is designed without a drive.

(11) The front idler set 3 has a first tensioning pulley 14 with a first pulley axis, a second tensioning pulley 15 with a second pulley axis, a third tensioning pulley 16 with a third pulley axis, a fourth tensioning pulley 17 with a fourth pulley axis,

(12) on. a drive (not shown in more detail) for the second tensioning pulley 15 is provided, with which a torque can be applied to the second tensioning pulley 15 on the second pulley axis. Furthermore, a drive (also not shown in more detail) is provided for the third tensioning pulley 16, with which a torque can be applied to the third tensioning pulley 16 on the third pulley axis. Furthermore, a drive (also not shown in more detail) is provided for the fourth tensioning pulley 17, with which a torque can be applied to the fourth tensioning pulley 17 on the fourth pulley axis.

(13) The first tensioning pulley 14 is designed without a drive.

(14) The straightening unit 1 shown in FIG. 2 differs from the straightening unit 1 shown in FIG. 1 in the design of the rear tensioning pulley set 4 and the design of the front tensioning pulley set 3. In addition to the first tensioning pulley 8, the second tensioning pulley 9, the third tensioning pulley 10 and the fourth tensioning pulley 11, this has a fifth tensioning pulley 12 and a sixth tensioning pulley 13.

(15) a drive (not shown in more detail) for the second tensioning pulley 9 is provided, with which a torque can be applied to the second tensioning pulley 9 on the second pulley axis. Furthermore, a drive (also not shown in more detail) is provided for the third tensioning pulley 10, with which a torque can be applied to the third tensioning pulley 10 on the third pulley axis. Furthermore, a drive (also not shown in more detail) is provided for the fourth tensioning pulley 11, with which a torque can be applied to the fourth tensioning pulley 11 on the fourth pulley axis. Furthermore, a drive (also not shown in more detail) for the fifth tensioning pulley 12 is provided, with which a torque can be applied to the fifth tensioning pulley 12 on the fifth pulley axis.

(16) The first tensioning pulley 8 and the sixth tensioning pulley 13 are designed without a drive.

(17) The front tensioning pulley set 3 in the embodiment of FIG. 2 has a first tensioning pulley 14 with a first pulley axis, a second tensioning pulley 15 with a second pulley axis, a third tensioning pulley 16 with a third pulley axis, a fourth tensioning pulley 17 with a fourth pulley axis,

(18) on. a drive (not shown in more detail) for the second tensioning pulley 15 is provided, with which a torque can be applied to the second tensioning pulley 15 on the second pulley axis. Furthermore, a drive (also not shown in more detail) is provided for the third tensioning pulley 16, with which a torque can be applied to the third tensioning pulley 16 on the third pulley axis. Furthermore, a drive (also not shown in more detail) is provided for the fourth tensioning pulley 17, with which a torque can be applied to the fourth tensioning pulley 17 on the fourth pulley axis. Furthermore, a drive (also not shown in more detail) is provided for the first tensioning pulley 14, with which a torque can be applied to the first tensioning pulley 14 on the first pulley axis.

(19) FIG. 3 shows the forces applied to the measuring pulley by a metal strip partially wrapped around the measuring pulley and under tension. The quartz force sensors arranged in the cavities in the measuring pulley generate electrical charge. This is directly proportional to the force applied to the quartz.

(20) The strip length deviation, usually measured in 1-units and commonly used as a representative of strip flatness, can be calculated based on the following relationships:

(21) Local tensile stress in strip section i
Z,i=FR,ir_Roll/(A_Sensord) with F_R,i=Local radial force in N (sensor force) r_Roll=Radius of the measuring pulley A_Sensor=area of the sensor or the cover on the sensor that is in contact with the tape. d=strip thickness

(22) Tensile stress deviation of the belt section from belt section with maximum tensile stress:
Z,i=Z,lZ,max with Z,max=maximum of all local tensile stresses

(23) Local strip length deviation (flatness):
L/Li=Z,i/E with E=E-modulus

EXAMPLE

(24) FR,i=500 N r_Roll=300 mm A_Sensor=707 mm.sup.2 d=0.5 mm Z,l=424.4 MPa Z,max=430 MPa Z,l=5.59 MPa E=206 GPa L/1i=27.1 m/m=2.71 l-units.