Patent Publication Number: US-6209305-B1

Title: Driving and supporting device for transporting roller for textile fibers

Description:
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 resolution of the motor to the reaches of the transporting roller, an optimal supply of the fiber material can be produced. The step resolution amounts to a multiple of the resolution of the regions of the transporting roller. 
     The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view showing a central longitudinal section through a first device in accordance with the present invention with a direct drive of a transporting roller; 
     FIG. 1 a  is a view showing the transporting roller which forms a releasable unit with a hollow supporting shaft. 
     FIG. 2 is a view showing a central longitudinal section through a second embodiment of the inventive device with a direct drive of the transporting roller; 
     FIG. 3 is a view showing a central longitudinal section through a first device with a transmission drive for the transporting roller; 
     FIG. 4 is a view showing a central longitudinal section through a second device with a transmission for the transporting roller; 
     FIG. 5 is a view showing a central longitudinal section through a third device with a transmission for the transporting roller; 
     FIG. 6 is a view showing a central longitudinal section through a first device with a joint hollow bearing shaft for a drive motor and a transporting roller; and 
     FIG. 7 is a view showing a central longitudinal section through a second device with a joint hollow supporting shaft for the drive motor and transporting roller. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     A driving and supporting device for a transporting roller shown in FIG. 1 has a supporting plate  10  with a stepper motor  11  at its one side and with a transporting roller  12  having a corrugated surface at the opposite side. The motor  11  is connected through a flange  13  with a supporting plate  10 . The supporting plate  10  has a opening  14 . A hollow supporting shaft  15  for the transporting roller  12  is arranged in the opening. The transporting roller  12  rotates on the hollow supporting shaft  15  through roller bearings  16  and  17 . A drive shaft  18  of the motor  11  extends through the hollow supporting shaft  15 . 
     An outer ring  28  of the integrated assembly  12 ,  16 ,  17  is connected with the transporting roller  12  through a sliding fit. A three-part driving element  19 ,  20 ,  21  is arranged at the end of the drive shaft  18  and transmits the torque of the drive shaft  18  to the inner cylinder of the transporting roller  12 . The inner part  19  of the drive element is adjusted to for example a flattened shape of the drive shaft. The innermost drive element  20  is formed elastically in the radial and axial direction. The flange  13  of the motor  11  is connected through an elastic element  22  with a connecting piece  23  which is fixedly screwed with the supporting plate  10 . The elastic elements  22  are designed for an optimal vibration condition of the drive. 
     The transporting roller  12  forms with the hollow supporting shaft  15  a releasable unit which is shown in FIG. 1 a.  It is fixed in the axial direction by magnets  24  which are arranged on the supporting plate  10 . FIG. 1 also shows a counterroller  25  which is formed here as releasing roller of an open end-spinning machine, as well as a fiber guiding element  26  and a control unit  27  for the motor  11 . Also, the parts  25  and  27  are mounted on the supporting plate  10 . As can be seen from FIG. 1 a,  the transporting roller can be easily removed for example by post-lubrication of the bearing. 
     FIG. 2 shows a device which in principle is substantially similar to device of FIG. 1. A transporting roller  12 ′ is also supported on a supporting plate  10 ′ through a hollow supporting shaft  15 ′. The drive shaft  18  of the motor  11  is however fixedly connected with a rigid drive element  30 , which furthermore is connected through an elastic connection  34  with the inner cylinder of the transporting roller  12 ′ and transmits the torque of the drive shaft  18 ′ of the motor  11 ′ to the transporting roller  12 ′. The electrical connection takes the objective of mechanically uncoupling the bearing of the motor  11 ′ and the bearing of the transporting roller  12 ′ in the axial and radial directions. 
     FIG. 1 a  is a view showing the transporting roller which forms a releasable unit with a hollow supporting shaft; roller  42  is coupled through a transmission. The transmission has a pinion  43  which is fixedly connected with the motor shaft  44 . The pinion  43  engages in an inner toothing  45  of a receptacle  46  which is fixedly connected with a shaft  47 . The shaft  47  is connected at its one end for joint rotation with a drive element  48 , through which the torque of the shaft  47  is transmitted to the transporting. FIG. 3 shows a device in which a motor  41  is connected with a roller  42 . The motor shaft  44  and the shaft  47  of the transporting roller  42  are offset relative to one another. In the solution shown in FIG. 3 no additional bearing locations for the transmission parts  43 ,  46 ,  47  are needed. 
     A further embodiment of the transmission between a motor  51  and a transporting roller  52  is shown in FIG.  4 . Here the transporting roller  52  is fixedly connected with the hollow supporting shaft  53  which rotates on a shaft  55  through a roller bearing  54 . The shaft  55  is fixedly mounted on the supporting plate  50 . The motor shaft  56  transmits its torque through a pinion  57  to the inner toothing of a receiving element  58  which is fixedly connected with the hollow bearing shaft  53 . The motor  51  is again mounted on the supporting plate through elastic element  59  so that a slight radial pretensioning of the of the transmission element  57  and  58  is produced. This slight radial pretensioning compensates for the radial gap of the bearing. Therefore the drive shaft  56  of the motor and transporting roller  52  are mechanically uncoupled from one another. In this embodiment, the are mechanically uncoupled from one another. In this embodiment, the bearings are available with a relatively great radial and axial gaps and thereby a cost-favorable construction is formed. The same is true for the solution of the transmission shown in FIG.  3 . In this embodiment the motor shaft  56  and the bearing and driving unit  53  of the transporting roller  52  are offset relative to one another. Therefore, sufficient space is available on the device for mounting and required service works. 
     In a third embodiment of a transmission connection between a motor  61  and a transporting roller  62  shown in FIG. 5, the drive shaft  63  of the motor  61  extends into a recess  64  of a shaft  65 , with which the transporting roller  62  is fixedly connected. Moreover, the transmission is arranged in the recess  64  and includes a pinion  66  and an inner toothing  67  on the shaft  65 . The shaft  65  rotates in a receptacle  68  for the motor  61 . In contrast to the devices shown in FIGS. 3 and 4, here the shaft  65  as well as the roller bearing  69  between the shaft  65  and the recess  68  can have a greater size, so that the service life of the device can be increased. The illustrated support is very space economical and stable. 
     FIGS. 6 and 7 show arrangements in which the motors  71  and  81  and the transporting roller  72  and  82  are supported in a common hollow supporting shaft  73  and  83 . The hollow supporting shaft  73  and  83  extend  6  the motor shaft  74  drives the transporting roller  72  directly through a drive element  75 . The shaft  74  rotates on the inner cylinder of the hollow supporting shaft  73  through a ball bearing. For the gap-free adjustment of the support, two springs  76  are provided. By corresponding tightening of a nut  77  at the end of the drive shaft  74 , a corresponding pretensioning is produced and moreover the required pressure is obtained for a reliable driving of the connecting element  75 . As in all previous examples, here again the transporting roller  72  is fixed in the axial direction by the magnet  78 . 
     In the device of FIG. 7 a shaft  84  is fixedly mounted in a receptacle  85  of the motor  81 . Drive magnets  86  of the motor  81  are located in the action region of the excitation field of a stator  87  and kidney-shaped stator windings  88 . The torque is transmitted through a receptacle  89  to the hollow supporting shaft  83  of the transporting roller  82 . The axial pulling force of the magnet  86  serves for the axial adjustment of the support through a spring  90  for the required gap-free running and driving of the transporting roller  62 .