EP0683704B1 - Tape take-up reel with an electric motor drive, especially one with a speed-transforming transmission - Google Patents

Abstract

The invention pertains to a tape take-up reel with an electric motor drive (A1, A2). In order to be able to wind tapes (B) in the shortest possible winding time, with constant tension on the tape, while providing a low technical complexity, the invention divides the winding operation into two phases. In the initial phase the winding proceeds with a constant tension on the tape at a constant rotational speed (n) of the reel cylinder (HT2), whereas in the second phase the winding proceeds with constant tension on the tape at a constant tape speed (V). Allowing for a negligible lengthening of the winding time, the driving torque of the drive motor can be reduced as a function of the point in time at which the changeover from constant rotational speed (n) to constant tape speed (V) occurs.

Description

The invention relates to a take-up reel for tapes with an electric motor drive, in particular having a transmission gear, which can be switched to different winding speeds by a control and regulating device, with the take-up in the initial phase increasing at a predetermined maximum tape speed and then at a predetermined tape speed he follows.

Depending on the thickness of the tapes, tapes that come from rolling mills, for example, are wound on take-up reels with different tape pulls (tensile forces) and different speeds. While thick tapes are wound with large tape pulls and low speeds, thin tapes are wound with small tape pulls and high speeds. Under these winding conditions, both thick strips and thin strips can be wound into sufficiently strong coils in reasonable winding times. The Different speeds and belt pulls for the thick and thin belts can be achieved with the same drive power by switching the transmission gear to different transmission ratios.

In order to take full advantage of the performance of the electromotive drive, the electromotive drive of take-up reels for reversing rolling mills for strips, in which the strip becomes thinner in several rolling passes, could be equipped with a transmission gear that can be switched to one or more gear ratios and which can be opened after each or several rolling passes a higher translation can be switched. However, in addition to the time required, this would have the disadvantage that the gear would have to be relieved of the belt tension for the changeover. This relief would easily lead to the coil being wound up. It is therefore common practice to use gearboxes with just one gear ratio for such applications.

In order to be able to use a take-up reel of the type mentioned at the beginning for tapes of different thicknesses, the electric motor drive must be designed on the one hand for the maximum tape tension and on the other hand for the maximum speed. As a result, the available electric motor drive is oversized for many applications.

In order to achieve the shortest possible winding times, the gear ratio of the gearbox is chosen so small that the maximum winding speed is reached even with the smallest winding diameter. While with an electric motor drive with a manual gearbox, the If the torque on the winding drum is increased by switching the gear to a lower gear ratio, the large torque must be made available by the drive motor in a take-up reel without a switchable gear. This means that the motor and its supply must be designed accordingly. The additional costs associated with a large reversing rolling mill can amount to 2 to 3 million DM.

In a known take-up reel of the type mentioned at the beginning (JP-A-63 140 724), take-up takes place in two phases at different speeds. However, the prior art also contains no information about the criteria according to which the speed is increased in the initial phase and the criteria according to which the strip tension is to be adjusted. As soon as the specified maximum belt speed is reached, the control system changes from the belt tension to the speed of the drive motors. The control is carried out depending on the maximum diameter of the wound coil and the current winding diameter. The equipment required for this type of winding is great.

The invention has for its object to provide a take-up reel of the type mentioned in particular for reversing rolling mills, which enables short winding times with little investment in engineering.

This object is achieved in a take-up reel for tapes of the type mentioned at the outset in that the take-up takes place in the initial phase as well as thereafter with constant tape tension, the take-up speed and then the maximum belt speed reached is kept constant.

The different modes of operation of the take-up reel in the initial phase and afterwards make it possible to use an electromotive drive at the expense of an extremely slightly longer winding time, which is not operated with the direct drive at the maximum possible speed from the rolling mill or with a higher gear ratio when using a transmission gear Gear ratio can be operated. In the case of an electric motor drive with transmission gear, the required torque of the motor is reduced accordingly. In any case, it means significantly lower costs for the electric motor drive.

mit D_I als Coildurchmesser am Anfang des Aufwickelns durchgeführt.According to a first embodiment of the invention, the winding is carried out at a constant reel speed up to a coil diameter ${\text{D}}_{\text{V}}{\text{= 1.2 D.}}_{\text{I.}}{\text{- 2.0 D.}}_{\text{I.}}$

with D _I as the coil diameter at the beginning of the winding.

Fig. 1

eine Reversierwalzanlage für Bänder mit zwei Aufwickelhaspeln in schematischer Darstellung,

Fig. 2

ein Diagramm für die relative Bandgeschwindigkeit in Abhängigkeit von der aufzuwickelnden relativen Bandlänge und der relativen Aufwickelzeit und

Fig. 3

ein Diagramm für das Antriebsmomentenverhältnis und den Zeitanstieg in Abhängigkeit vom relativen Coildurchmesser.

An exemplary embodiment of the invention is explained in more detail below with reference to a drawing. In detail show:

Fig. 1

a reversing rolling mill for strips with two take-up reels in a schematic representation,

Fig. 2

a diagram for the relative tape speed as a function of the relative tape length to be wound and the relative winding time and

Fig. 3

a diagram for the drive torque ratio and the time increase depending on the relative coil diameter.

In a reversing rolling mill W, two identical rewinders with a reel drum HT ₁ , HT ₂ and an electromotive drive A ₁ , A _{2 are} provided. In several rolling passes, the strip B to be rolled is unwound from the HT ₁ reel drum and wound onto the HT ₂ reel drum and vice versa. During each winding process, the force of the strip tension is kept constant, while depending on the diameter of the coil C ₁ , C ₂ , namely at the diameter D _V , which is larger than the smallest inner diameter D _I (= diameter of the reel drum HT ₂ ) and smaller than the outer diameter D _{A of} the finished coil, from initially constant speed n of the reel drum HT ₁ , HT ₂ to constant Winding speed V of the tape B is switched. For this purpose, a control and regulating device ST is provided, which receives the speed n of the winding reel drum HT ₂ , the diameter D of the coil C ₂ and the speed V of the strip B and the strip tension F as operating parameters.

. Bei einem Coildurchmesser D_V wird die maximale Anlagengeschwindigkeit V_max erreicht, die durch das Walzwerk W bestimmt ist. Für Coildurchmesser D > D_V wird die Aufwickelhaspel HT₂ mit konstanter Bandgeschwindigkeit und damit auch mit veränderlicher Drehzahl n betrieben. Die Drehzahl beträgt dann $${\text{n = n}}_{\text{max}}{\text{. D}}_{\text{V}}\text{/D.}$$

As already stated, the invention provides for the winding to be controlled in such a way that with a small coil diameter D <D _v , the reel drum HT ₂ is initially wound at a constant speed n. As the coil diameter D increases, the belt speed V increases. The belt speed is then ${\text{V = V}}_{\text{Max}}{\text{. D / D}}_{\text{V}}$

. With a coil diameter D _V , the maximum line speed V _{max is} reached, which is determined by the rolling mill W. For coil diameters D> D _V , the take-up reel HT _{2 is operated} at a constant belt speed and thus also at a variable speed n. The speed is then $${\text{n = n}}_{\text{Max}}{\text{. D}}_{\text{V}}\text{/ D.}$$

The diagram in FIG. ₂ shows how the speed V increases with the winding time and thus also with the wound strip length for different diameter ratios D _I / D _{V of} the reel drum HT ₂ and the coil C ₂ . The diagram shows that only a short winding time or a short strip length does not wind at the maximum system speed V _max . The time loss caused by this mode of operation with a constant winding speed n compared to winding at the maximum winding speed from the beginning is therefore small.

This time loss is plotted in the diagram in FIG. 3 for different diameter ratios D _V / D _I.

eine Verringerung des Antriebsmomentes des Motors auf 70% möglich. Der dabei eintretende Zeitverlust beträgt nur 1,3%. Berücksichtigt man aber, daß in der Praxis die ersten Windungen beim Anwickeln in keinem Fall mit maximaler Drehzahl bzw. maximaler Geschwindigkeit gewickelt werden können, ist der auf die Verringerung des Antriebsmomentes zurückzuführende Zeitverlust noch geringer. Der Zeitverlust kann allerdings auch dadurch kompensiert werden, daß man eine größere Bandgeschwindigkeit für die zweite Phase des Aufwickelvorganges wählt.The driving torque ratio is also plotted in this diagram as a function of the diameter ratio D _V / D _I. Since the maximum belt speed V _{max is} only reached when the winding diameter D _V is greater than the smallest diameter D _I , the electromotive drive A ₁ , A _{2 can be} equipped with a larger gear ratio. This means that a drive motor with a correspondingly lower torque can be used. For example, there is a relationship ${\text{D}}_{\text{V}}{\text{/ D}}_{\text{I.}}\text{= 1.4}$

the drive torque of the motor can be reduced to 70%. The loss of time that occurs is only 1.3%. However, if one takes into account that in practice the first turns cannot be wound at maximum speed or maximum speed during winding, the time loss attributable to the reduction in the drive torque is even less. However, the loss of time can also be compensated for by choosing a higher belt speed for the second phase of the winding process.

The invention is not limited to the exemplary embodiment described with a transmission gear. It can also be used in manual transmissions. Depending on the gear ratio selected, a reduction in the torque of the drive motor is possible.

For reel with direct drive, i.e. Without transmission gear, the invention enables a reduction in the maximum speed of the drive motor.

Claims (2)

1. A recoiler for strips (B), having an electric motor drive (A₁, A₂) which has more particularly a step-up transmission and can be switched by an opened and closed control device (ST) to different coiling speeds (V), wherein the coiling is performed in the initial phase at a strip speed increasing until a predetermined maximum strip speed (V_max) has been reached, and thereafter at a predetermined strip speed, characterized in that the coiling is performed both in the initial phase and also thereafter with a constant strip tension, the coiling speed (n) in the initial phase and thereafter the maximum strip speed (V_max) reached being kept constant.
2. A recoiler according to claim 1, characterized in that coiling is performed at a constant coiling speed (n) up to a coil diameter ${\text{D}}_{\text{V}}{\text{= 1.2 D}}_{\text{I}}{\text{- 2.0 D}}_{\text{I}}$

   

   , where D_I is the coil diameter at the start of coiling.

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