Abstract:
The present invention concerns a procedure for the reworking of a open-end spinning apparatus for a spin rotor, which is carried in the V-notch between support disks and is supported by a ball axial thrust bearing. Where the reworking is concerned, the bearing block of the open-end spinning apparatus is dismounted, the ball axial thrust bearing is removed from the bearing block and in accord with the invention, is replaced by an aerostatic bearing in the bearing block.

Description:
BACKGROUND OF THE INVENTION 
     The present application concerns a procedure for the reworking of an open-end spinning apparatus as well as a bearing arrangement for a spin rotor of an open end spinning apparatus. Open-end rotor spinning apparatuses for open-end spinning machines, for example, such as are made by the firm W. Schlafhorst AG &amp; Co. and Rieter Ingolstadt Spinning Machine Construction AG, are generally comprised of a multiplicity of spinning elements as well as a plurality of apparatuses for the winding of the spun yarn. Such a spinning unit possesses a spin rotor, which, by means of a drive motor, is set into rotational motion. Of considerable importance in this matter is the manner in which the spin rotor is carried on its bearings. 
     The bearing assembly for the rotor shaft divides itself into a radial and an axial bearing system. In the case of the radial bearing, the spin rotor is set into a V-shaped notch between two support disks. The axial bearing arrangement, and the reaction to the axial force caused by the spin rotor which this generates during operation, is contained on a thrust bearing. Until a few years previously, the axial thrust bearing in the case of machines of the above described manufacturers, and thereby a substantial part of this type of spinning machines, was equipped with a ball on which the rotor shaft rested while turning. The necessary lubrication of this ball was carried out with the aid of an appropriate lubricant. 
     These types of axial bearing arrangements, however, have the disadvantage that, in order to enable the important rotation of the ball, special demands were called for in regard to the lubrication. In the majority of cases, for this reason, these balls were placed above an oil bath or an oil-containing medium for lubrication. Besides the continuous rotation of the ball, and therewith the danger of considerable abrasive wear, this kind of axial rotor bearing arrangement had the additional disadvantage that lubricant, because of the vibration and high RPM of the rotor shaft, migrated out of the bearing box and contaminated the spinning machine, i.e., the spinning apparatus. Because of the oily surfaces in the bearing area, it happened that fine dusts and fibers of the spinning process could agglomerate on the machine and encrust themselves. This buildup could then lead to disadvantages in the formation of yarn. Such waste material patches that loosened themselves could enter into the to-be-spun fiber material and cause subsequent contamination and non-uniformities in the product. 
     Moreover, these contaminating deposits had the disadvantage that a large maintenance expense continually accrued. Thus, at regular periods, a cleaning of the spinning machine as well as a monitoring of the lubrication supply of the axial bearing had to be done. Under these circumstances, it was often necessary to refill the lubricant containers, which increased the maintenance time even more. 
     In order to set aside the disadvantages of spinning machines with open-end spin rotors supported by bearings of this kind, the state of the technology developed a different approach to axial bearing systems. The arrangement of the bearings for the spin rotors was done without the ball and further allowed the removal of the lubrication, which contaminated the fibers. This type of bearing support has been made known by EP 0 435 016 A2. 
     Following the introduction of this type of pneumatically driven axial thrust bearing system, which avoided the above described disadvantages, attempts were made to substitute these modem bearing arrangements with simplified ball axial thrust bearings, where the construction of the bearing assembly was simple to the extent that an exchange of these two bearing systems could be carried out. For this required construction, the improved version of the pneumatic axial thrust bearing arrangement was used, and the ball axial thrust bearing was simply installed in the receiving enclosure of this modem pneumatic bearing. By this means, a version (minimized in size) of the known oil lubricated, ball axial thrust bearing assembly was pushed into the receiving housing for the modem pneumatic axial bearing system. Through this kind of retrofit of the bearing assembly with conventional systems, the desired advantages of the modem axial bearing methods were circumvented in order to substitute for them apparatuses which were constructed according to the older types of bearings. This kind of bearing design still, as demanded by its components, called for an oil-based lubrication. Instead of refitting the obsolete bearing system with modem pneumatic bearings, the state of the technology, contrary to this, surprisingly simply retrofitted the modem and improved bearing system with the old. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     Thus, it is a principal object of the invention to allow many thousands of spinning apparatuses now in operation with an oil-media lubrication system of the rotor to be reworked without great cost by an appropriate procedure and an apparatus to execute the procedure. The reworking would permit the spinning apparatuses to meet the demands, which have been placed on spinning machines without the necessity of replacing the complete spinning apparatus or machine. The investment amounts for the modernization are held to a minimum and remain restricted to the necessary components. Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention. 
     The present purpose of the invention is solved by dismounting the bearing block from the open-end spinning apparatus, separating the axial bearing from the bearing block, and replacing it with an axial bearing carrier for an aerostatic axial bearing equipped with a matching surface on the bearing block. The reworking allows, in this operation, only a small expenditure of time and money in comparison to the substitution of new spinning machines or a new, modernized open-end spinning machine for machines containing the axial ball bearings. 
     Reworked open-end rotor spinning machines retain essentially the same advantages in regard to the character of the bearing assemblies as do newly purchased open-end rotor spinning machines already equipped with the recently installed pneumatic axial bearing system for the spin rotor. For the rework, essentially only the bearing block of the open-end rotor apparatus to be reworked needs to be dismantled, following which, in a simple manner, the axial bearing assembly found on the block can be separated, and, in accord with the invention, replaced with an axial pneumatic bearing carrying block. 
     The reworking can even be accelerated by, for example, doing the reworking section by section. The corresponding parts of the rotor bearing assembly on the open-end spinning machine can be removed and reworked in one section, while the other sections of the spinning machine remain in operation. In another advantageous method, already reworked bearing assemblies can be held on the ready, so that, upon the next removal of the original bearing, the new component can serve as an immediate replacement. Thus, only a very short break in production would occur. The now removed original bearing assemblies, can be reworked at an optional time and place, so that, subsequently, these reworked assemblies can be exchanged piece for piece for existing original bearing assemblies. 
     In an advantageous development of the invented procedure, the removal of the ball axial bearing assembly can be effected by machine cutting, for instance, by sawing or milling, or even by non-machine cutting such as by laser or by electron beam. In this way, a plane of separation, i.e., a separating surface, is generated quickly and advantageously, which can be immediately turned to rework operations. Preferably, this follows as an additional step in the procedure. Also, the plane surface is generated with a minimum of roughness depth, which advantageously serves as a matching surface for another complementary surface. Such a plane surface improves the fitting of the axial bearing block surface to the existing bearing block. 
     The separation of the ball axial bearing is carried out favorably in such a manner that the plane in which the separation occurred lies parallel to the plane in which the support disks lie, that is, that plane which is formed by the support disk pair proximal to the rotor, or the support disk pair proximal to the shaft end. Advantageously, the separation can be made between the two planes of the two above mentioned pairs of support disks. An advantageous separation line can be achieved by having the line in its course suddenly bend, and run perpendicular to the above described planes of the support disks. 
     The axial bearing carrier is advantageously designed with a corresponding matching surface, so that the separating surface is appropriate for the fitting of the axial bearing carrier onto the existing bearing block. This match is especially true, when the bearing block has been correspondingly machined. In a further advantageous development of the procedure, the separating surfaces are provided with fastening means for their union. In this way, the advantage is gained that the fastening of the axial bearing carrier is simple and quick, as well as being exact in surface match. In a particularly favorable option, the fastening means includes a boring, which preferably possesses an inner threading. Thereby, the fixing of the axial bearing carrier onto the existing bearing block is very simple, i.e., with threaded bolts. 
     By means of the invented bearing arrangement, an economical bearing has been constructed, the bearing block of which retains the advantages of the original bearing system of the spin rotor by means of support disks and at the same time inherently possesses the advantages of a pneumatic axial bearing of the spin rotor. For this purpose, the axial bearing carrier is equipped with a receptor for a bearing surface of a pneumatic axial bearing. By means of the construction of a matching surface, no further measures are required for the installation of the bearing surface of the axial bearing to the spin rotor, at least that call for a change of the angularity of the bearing surface in relation to the axis of the rotor shaft. 
     In a particularly advantageous development of the bearings, the separating and the matching surfaces are simultaneously shaped, so that they, in connection with the axial bearing carrier, assure that no adjustments are necessary which alter the placement of the bearing surface in the axial direction of the spin rotor. This is particularly favorable, since no time for such adjustment can be lost and, moreover, no special knowledge is required of the maintenance personnel. The separation surface is machined for this reason in accord with the invention. The separation surface forms a centering and positioning surface of the bearing plate of the axial bearing for the rotor shaft, which will be rotationally carried thereon. 
     In a particularly advantageous improvement of the invention, the separation surface is provided with fastening means with the help of which the fastening of the bearing carrier is simple and advantageous. In a particularly advantageous development of the invention, this fastening means is a boring provided with a thread. In a further advantageous improvement of the invention, the separation surface possesses a centering means for the centering, or alignment, of the bearing carrier onto the existing bearing block. For example, these centering means might be centering pins, or complementary borings for the same. By these alignment means, a rapid and sure centering of the bearing carrier on the existing bearing block can be carried out during the installation. These alignment means simplify the mounting and accelerate the installation of the bearing components and thereupon the rework of the open-end rotor spin apparatus. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following, the invention will be described with the aid of the drawings. 
     FIG. 1 shows a bearing assembly of an open-end rotor spinning apparatus before the reworking; 
     FIG. 2 shows the reworked view of the assembly of FIG. 1, following the installation of the axial bearing carrier of an aerostatic axial bearing; 
     FIG. 3 shows the ball axial thrust bearing of FIG. 1 in a cross-sectional view; and 
     FIG. 4 shows the axial bearing carrier of FIG. 2 in a perspective presentation. 
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the presently preferred embodiments of the invention, one or more examples of which are shown in the figures. Each example is provided to explain the invention, and not as a limitation of the invention. In fact, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a further embodiment. It is intended that the present invention cover such modifications and variations. 
     FIG. 1, in combination with FIG. 3, shows the bearing arrangement of an open-end spinning apparatus, in accord with the state of the technology, with a ball axial bearing  13  prior to the rework operation. The bearing arrangement  10  comprises one bearing block  11  on which the support disks  12  as well as the ball axial bearing  13  are placed. Such a bearing arrangement, for instance, is made known by DE 41 21 387 A1, (see FIG. 2 of that patent). In the bearing system of FIG. 1, the support disks  12  are arranged pairwise, so that they present two V-notches  121  in which the rotor shaft is carried. At the end remote from the ball axial bearing  13 , the rotor shaft  14  carries the open-end spin rotor  140 . Due to a (not shown) driving element, which, in the state of the technology is largely based on tangential belts, the spin rotor  140  is driven by the rotor shaft  14  and set into rotation. Respectively, two support disks  12  bound to one another are driven by an axle  15  and carried on support disk bearing  16 . The support disk bearings  16  are received in a semicircular recess  17 . By means of clamp  18 , the support disk bearings  16  are pressed into the recess  17  of the bearing block  11  and there retained. The clamp  18 , at the same time, is affixed to the bearing block  11 . The axles  15  of the support disks  12  are slightly skewed in relation to one another to the effect that the V-notch  121  between the support disks  12  generates an axial thrust against the rotor shaft  14 , which rests on the V-notch of the disks, in the direction of the ball axial bearing of the bearing assembly  10 . 
     The ball axial bearing  13  possesses a container  19  which is closed by a cover  20 . Within the container  19 , a ball  5  is found at the elevation of and abutting the rotor shaft  14 . The ball supports itself on the side remote from the rotor shaft  14  on a recessed detent  21 , which accepts the ball in a cuplike receiver. The recessed detent  21  can be adjusted with an adjustment screw  22 , which is locked by means of the nut  220 . 
     For the necessary lubrication of the ball  5 , the ball axial bearing  13  possesses a container  3 , which is remote from the cover. The container  3  holds the lubricant  31  which lubricates the ball during its rotation. The lubricant  31  is brought to the point of lubrication of the ball  5  by means of a wick  32 . 
     The bearing block  11  is fastened to the spinning machine framing  24  by means of the fastening screws  23 , which is shown only schematically. For the proposed rework of the open-end spinning apparatus, the bearing block  11  must first be removed from the spinning machine, and thus demounted from the spinning apparatus by the loosening of the fastening screws  23 . For this purpose, it is advantageous to stop the rotor driving means (not shown), so that the bearing block with the support disks  12  and the ball axial bearing  13  can be taken out of the spinning machine. Prior to this step, advantageously, the spin rotor  140  with its rotor shaft  14  have already been removed from the bearing assembly  10 . After the removal of the bearing assembly  10  and the removal of the clamp  18 , the support disks  12  also are removed from the bearing block  11  for the sake of simplicity, so that further operational steps on the bearing block  11  can be carried out without difficulty. 
     The next work step in the rework program on the open-end spinning machine will be the necessary removal of the ball axial bearing  13  from the bearing block  11 . This removal is accomplished by the literal cutting off of the ball axial bearing  13 , for instance, by sawing. The cut is to be made along one of the separation lines marked, for example, as A to E, whereby the left and the right side of the bearing block  11  can possess the same, or different section lines (A, B, C, D, E). Because of the cutting off of the ball axial bearing  13 , there arises along the cutoff lines (A to E) a separation surface to which connects the axial bearing carrier  4 , which has an accommodating counter surface to accommodate a pneumatic axial bearing (See FIG.  2 ). 
     The bearing assembly  10  from FIG. 2 is a re-worked bearing assembly in accord with the invention. By the cutting off of the ball axial bearing ( 13 ) (see FIG.  1 ), the separation surface  25  is so free that an axial bearing carrier  4  of the bearing surface  41  for a pneumatic axial bearing  42  can be placed thereon in accord with the invention. The separation surface  25 , as shown in FIG. 2, is remachined after the cutting off of the ball axial bearing  13 , so that the cut separation surface  25  has a smooth flat surface onto which the axial bearing carrier  4  with its matching surface  45  can make a seamless joining. The machining of the separation surface  25  is carried out in the embodiment of FIG. 2 by means of machine cutting, that is, by milling. By the machining, the separation surface receives the requirement for the bearings of the support disks  12  and subsequent to this the rotor shaft  14  which is carried on the support disks  12 . The separation surface then serves as a detent surface matching the complementary surface  45  of the axial bearing carrier  4 . 
     The separation surface  25 , which, in FIG. 2 is formed from two partial surfaces located respectively right and left of the V-notch of the bearing block  11 , possesses two means of fastening  440 , which are indicated in FIG. 2 by means of a dotted line. The fastening means comprises, respectively, a boring through which a threaded bolt can be run until it extends into the axial bearing carrier  4 . The axial bearing carrier  4  lies with its matching surface  45  on the separating surface  25  of the bearing block  11 . Separation surface  25  and matching surface  45  have been shaped to be complementary to one another. On this account, the bearing surface  41  of the pneumatic axial bearing  42  falls into its correct position following the assembly of the axial bearing carrier  4  in relation to the rest of the bearing components, and especially in relation to the free end of the rotor shaft  14 . 
     In the assembly of the axial bearing carrier  4 , and in the recess formed by a clamping element  46  for the pneumatic axial bearing  42 , an assembly opening has been introduced that shows the position in which the matching surface  45  and the separation surface  25  must be affixed together by the fastening means  440 . For the axial adjustment of the pneumatic axial bearing  42  in relation to the end of the rotor shaft, the clamping element  46  is in the shape of a clenched fist, so that the pneumatic axial bearing  42  can be fastened in the correct axial position with the clamp screw  47  on the axial bearing carrier  4 . The axial bearing carrier  4  possesses respectively two fastening means  440 . However, it is quite possible to also install these in a bearing block that has fastening means formed in a different manner. 
     FIG. 3 shows the ball axial bearing of FIG. 1 in a cross-sectional view. The rotor shaft  14  lies, when in operation, against the ball  5 . For this purpose, the rotor shaft  14  has a recessed, cup-like detent which bears against the ball  5 . The ball  5  for its part abuts the adjustment screw  22 . The adjustment screw  22  is locked by means of the nut  220 , and thus is non-rotatable. For the lubrication of the ball  5 , a container for holding lubricant  31  is located below the ball. The lubricant is oil, which, is brought into contact with the surface of the ball  5  by means of a wick  32 . A chamber  19  of the ball axial bearing  13 , which is located above the oil container, is closed from above by the cover  20 . The rotor shaft  14  extends into this chamber  19  through a penetrative opening, whereby it is encompassed by a surrounding shell  33  which aids in preventing the leakage of oil to the surroundings. 
     Alternative to the methods and ways depicted in FIGS. 1 and 2 for the separation of the ball axial bearing  13 , it is entirely possible, that first the ball is removed from the ball axial bearing  13 , and subsequently, in the interior of chamber  19 , an axial bearing carrier is placed with a receiving module for the pneumatic axial bearing. For this purpose, the shell  33  as well as the ball retainer  51  must be removed. Ball retainer  51  limits the mobility of the ball  5  in the ball axial bearing. Then, on the cut surface of the shell  33 , which now becomes a separation surface  300 , there would be a matching complementary surface  45  of a correspondingly finished axial bearing carrier  4  (not shown). 
     In an additional embodiment for the removal of the ball axial bearing  13 , the interior of the chamber  19  is machine finished to cylindrical form and on the now ring shaped separation surface  300 , for instance, an annular axial bearing carrier  4  (not shown) is installed that takes up the bearing surface of a pneumatic axial bearing. The separation surfaces of the various embodiments of separation of the ball axial bearing are to fulfill their function, however, in the same manner as shown in FIGS. 1 and 2. 
     FIG. 4 shows the axial bearing carrier in accord with the invention and as it is installed in FIG.  2 . The axial bearing carrier possesses, respectfully, right and left from the pneumatic axial bearing  42 , a matching surface  45 , with which it is positioned on the separation surface of a reworked bearing system. In order that installation may be made with various bearing blocks, for example, or from different spinning machine models, the axial bearing carrier  4  of FIG. 4 exhibits respectively two fastening means  440 . Respectively, the upper means is a blind boring which is provided with an internal thread. Again respectively, the lower means is shown as a through boring through which a fastening device, such as a bolt, of the proper size can be screwed for fastening into the matching reworked bearing block. Besides the use of the boring as a fastening means, it can also serve for the exact positioning of the axial bearing carrier. To this purpose, for instance, other fastening devices, such as a drift pin or positioning pin, can be employed in the boring, which works together with a corresponding working separation surface of a reworked bearing block. 
     For the affixing of the pneumatic axial bearing  42  on the axial bearing carrier  4 , the axial bearing carrier  4  possesses a clamp  46  designed in the form of a clenched fist. By means of bolt  47 , the sheath-like designed pneumatic axial bearing  42  with its bearing plate  41  is fastened upon the axial bearing carrier. By means of the advantageous formation of axial carrier  4  and the clamp  46 , the bearing plate can be located simply in its axial direction, axial being in reference to the axis of the rotor shaft. In operation, the axial bearing is provided with compressed air through a (not shown) air-feed line on the side of the bearing plate opposite to the bearing surface  41 . Besides the described embodiments for separation and changes in the bearing arrangements, other embodiments are also possible. These other embodiments need only to refer to the above-described features to be able to make use of the pneumatic axial bearing and to position it correctly. 
     It will be appreciated by those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention. It is intended that the present invention include such modifications and variations as come within the scope of the appended claims and their equivalents.