Textiles: spinning – twisting – and twining – Apparatus and processes – Open end spinning
Reexamination Certificate
1997-12-01
2001-04-03
Stryjewski, William (Department: 3741)
Textiles: spinning, twisting, and twining
Apparatus and processes
Open end spinning
C057S100000, C019S258000
Reexamination Certificate
active
06209305
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a driving and supporting device for a transporting roller for textile fibers, in particular for a drawing roller of an open end spinning machine.
The drawing roller for an open end spinning machine guides the fiber material to be spinned to the machine. For transportation of the fibers, relatively high transfer forces are required. Also in rough spinning conditions, sporadically high radial and axial loads can occur during mounting, service or operation of the machine. The running accuracy of the drawing roller is decisive for the quality of the produced yarn. For the automatic spinning, a drive for the drawing roller which is independent from other parts, such as rotor drive and release roller, is of great advantage. As a rule, the drawing rollers of several spinning boxes have been centrally mechanically driven. An individual control of the individual drawing rollers of the spinning boxes is therefore however not possible. By means of an electrically controlled braking coupling, the drawing roller during the spinning process can be started, and in the event of a thread breakage, turned off.
Such a coupling however makes possible only two operational conditions: running with the rotary speed of the central drive or stopping. A stopping. A rotary speed regulation for example for spinning is not possible. Individual motor drives has been proposed for the drawing rollers, which are substantially flexible and with which high yam qualities could be realized. In the known individual motor drives, the drawing roller is supported on the drive shaft of the motor and thereby forces acting in the radial and axial direction on the drawing roller are completely transmitted to the motor bearing and their surface life is substantially limited. On the other hand, in the case of a separate mounting of shaft and motor they are coupled with one another. Such a coupling however occupies a substantial place. Moreover, the motor bearing remains loaded by transverse forces. The stepper motors are rigidly mounted on the machine. The vibration problems and the noise generation in the resonance region of the motor are a serious problem from the machines with 200-300 drive units.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a driving and supporting device for a transporting roller for textile fibers which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a driving and supporting device for a transporting roller for textile fibers, in particular for a drawing roller for textile fibers in particular for a drawing roller of an open end spinning machine, in accordance with which the roller is driven by an electric motor having a drive shaft with a torque transmitted to the transporting roller, and the transporting roller is supported in an axial and a radial direction on a part which is mechanically completely uncoupled from the drive shaft of the motor.
In this construction the drive shaft of the motor does not serve simultaneously for supporting the transporting roller. During the torque transmission between the drive shaft of the motor and the transporting roller, the drive shaft of the motor however must take tangential forces and not the relatively great radial and axial forces which act on the transporting roller. The motor bearing is therefore loaded only a little and has a correspondingly long service life.
Advantageously, the electric motor can be formed as a stepper motor, in particular a hybride motor which is very accurately controllable. Hybride motors have very small reaction times and a high breaking moment, which is required in particular during a thread breakage. The proposed driving device is especially space-economical and can be easily mounted on a supporting plate. Advantageously the motor can be supported elastically on the supporting plate in the axial and radial direction. Thereby the adjustment of an optimal vibration condition of the motor or the whole unit of the motor and the bearing device is possible. As a result, an exceptionally high running quietness of the transporting rollers and the motors is provided which is characterized acoustically by a low noise level. In accordance with an advantageous embodiment of the invention, the motor and the transporting roller can be supported opposite to one another on different sides of the supporting plate. The transporting roller can be anchored for example in the axial and radial direction on a hollow supporting shaft anchored in an opening of the supporting plate.
In accordance with a first embodiment of the driving and supporting device, the drive shaft of the motor can pass through the opening of the supporting plate and through the hollow supporting shaft of the transporting roller. At its end, it can be elastically connected through driving elements with inner cylinder of the roller. In this arrangement, a very small space is needed for the arrangement. Transporting roller can be supported through rollers on the hollow bearing shaft.
Further advantages can be obtained when the hollow supporting shaft and the transporting roller form an assembly which is fixed in an axial direction by magnets to the supporting plate. Thereby the mounting of the bearing device of the transporting roller is especially simple. It includes a snapping mechanism acting in the axial direction. Also, the release of the transporting roller from the device and in some cases an exchange of the motor is therefore very simple.
The at least one driving element can be connected elastically with the drive shaft of the motor or the inner cylinder of the transporting roller. The elasticity must be high in the radial and axial direction, while in the tangential direction it is low. Thereby with a good torque transmission, an improved vibration uncoupling between the drive shaft of the motor and transporting roller is provided.
A further advantage of this arrangement is that both bearing systems operate independently from one another because of the two mechanically uncoupled axles of the transporting roller and the drive roller of the motor which are not radially axially loaded relative to one another. Instead of the direct torque transmission between the drive roller and the transporting roller, the drive roller of the motor can transmit its torque through a transmission to the transporting roller. The transmission can be designed so that no additional supporting points are needed. The use of the transmission has the advantage that the rotary speed-torque characteristic of the stepper motor can be better utilized.
By a corresponding selection of the conversion ratio, the step resolution of the drive can be again reduced. For this purpose, standard 1.8° stepper motors are utilized in full or half stepper operation. This makes possible a simple design of the control. The smaller torque of these stepper motors requires also a low power consumption. The transmission for transmitting the torque can be integrated in the hollow supporting shaft for the transporting roller.
In a third embodiment of the driving and supporting device, the motor and the transporting roller can be supported on a common hollow supporting shaft which is anchored in an opening of the supporting plate and projects at both sides outwardly beyond the supporting plate. In this case separate motor bearings are not needed and therefore a service life problem is resolved.
The inventive device is suitable not only for drawing rollers of open end spinning machines, but also generally for all applications in which a fiber band must be supplied with a relatively small speed and corresponding control. The release roller cooperating with the transporting roller and a fiber passage for a counter pressure roller, can be also supported on a common supporting plate. Supporting roller is preferably formed as a ridge roller. By a corresponding adaptation of the stepped reso
SKF Textilmaschinen-Komponenten GmbH
Striker Michael J.
Stryjewski William
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