US3911659A

US3911659A - Bearing arrangement for a spinning rotor of an open end spinning device

Info

Publication number: US3911659A
Application number: US459199A
Authority: US
Inventors: Gerhard Mandl
Original assignee: Maschinenfabrik Rieter AG
Current assignee: Maschinenfabrik Rieter AG
Priority date: 1972-08-17
Filing date: 1974-04-08
Publication date: 1975-10-14
Anticipated expiration: 1992-10-14

Abstract

A bearing arrangement for a spinning rotor of an open end spinning device wherein the spinning rotor comprises a shaft, at one end of which there is mounted a turbine and at the other end of which there is mounted a drive whorl. Antifriction bearings are provided for supporting the rotor shaft and the exterior of such bearings is rigidly mounted in a sleeve surrounding the rotor shaft. The sleeve is connected with the walls of a bore in the rotor housing via an elastic member surrounding such sleeve. The sleeve is a thin-walled light and rigid metallic sleeve member and the elastic member comprises a ring of elastomeric material placed upon the end of the thin-walled light metal sleeve facing the turbine. The ring provides an airtight seal for the room or compartment between the sleeve and the bore in the housing at the side of the ring facing away from the turbine. Further there are provided means between the ring sealing the compartment and the drive whorl for permitting penetration of air into said compartment between the sleeve and walls of the bore in the rotor housing. Such air penetration means may be constituted by a second elastic outer support member provided for the sleeve at the other end at the drive side confronting the drive whorl and/or by one or a number of holes or bores provided at the rotor housing.

Description

United States Patent [191 Mandl [4 1 Oct. 14, 1975 BEARING ARRANGEIVIENT FOR A SPINNING ROTOR OF AN OPEN END SPINNING DEVICE Gerhard Mandl, Winterthur,

Switzerland [73] Assignee: Rieter Machine Works Ltd.,

Winterthur, Switzerland [22] Filed: Apr. 8, 1974 [21] Appl. No.: 459,199

Related US. Application Data [63] Continuation-impart of Ser. No. 383,722, July 30,

1973, abandoned.

[75] Inventor:

[52] US. Cl. 57/58.89; 57/130; 308/26 [51] Int. Cl. DOIH 1/12; DOll-l 7/04 [58] Field of Search Primary Examiner lohn Petrakes Attorney, Agent, or FirmWemer W. Kleeman [57] ABSTRACT A bearing arrangement for a spinning rotor of an open end spinning device wherein the spinning rotor comprises a shaft, at one end of which there is mounted a turbine and at the other end of which there is mounted a drive whorl. Antifriction bearings are provided for supporting the rotor shaft and the exterior of such bearings is rigidly mounted in a sleeve surrounding the rotor shaft. The sleeve is connected with the walls of a bore in the rotor housing via an elastic member surrounding such sleeve. The sleeve is a thinwalled light and rigid metallic sleeve member and the elastic member comprises a ring of elastomeric material placed upon the end of the thin-walled light metal sleeve facing the turbine. The ring provides an airtight seal for the room or compartment between the sleeve and the bore in the housing at the side of the ring facing away from the turbine. Further there are provided means between the ring sealing the compartment and the drive whorl for permitting penetration of air into said compartment between the sleeve and walls of the bore in the rotor housing. Such air penetration means may be constituted by a second elastic outer support member provided for the sleeve at the other end at the drive side confronting the drive whorl and/or by one or a number of holes or bores provided at the rotor housing.

13 Claims, 3 Drawing Figures US. Patent Oct. 14, 1975 Sheet10f2 3,911,659

US. Patent Oct. 14, 1975 Sheet 2 of 2 3,911,659

BEARING ARRANGEMENT FOR A SPINNING ROTOR OF AN OPEN END SPINNING DEVICE CROSS-REFERENCE TO RELATED CASE The instant application is a continuation-in-part of my commonly assigned, copending U.S. application Ser. No. 383,722, filed July 30, 1973 now abandoned.

BACKGROUND OF THE INVENTION The present invention relates to a new and improved construction of bearing arrangement for a spinning rotor of an open end spinning device producing staple fiber yarns in a spinning mill operation.

A spinning rotor for open end spinning (hereinafter sometimes referred to as OE-spinning) arranged in a rotor housing in which sub-atmospheric pressure prevails, is provided at one end with a goblet-shaped fiber collecting surface, hereinafter called a spinning turbine, into which discrete fibers are fed, deposited, and twisted into a yarn, and from which there is then removed a completed yarn. Since the production capacity of a machine of this type possessing a multiplicity of such spinning devices depends directly upon the delivery speed of the yarn and also upon the number of turns per unit of time imparted to the yarn, there are required as high as possible rotational speeds for such rotors. The rotational speeds which are feasible with present day spinning technology are in the order of 50,000 to 60,000 rpm. Considering the magnitude of such rotational speeds, it should be self-evident that such high rotational speeds impose very high requirements upon the bearings. Hence, numerous experiments have been carried out for the purpose of improving the bearings of open end spinning rotors (hereinafter sometimes referred to as OE-rotors). Attempts have been particularly made to achieve a life of 20,000 operating hours for 90% of the bearings at rotational speeds up to 45,000 rpm. by using a flexible instead of a rigid bearing arrangement.

Such prior art bearing arrangements consist of two grease lubricated shoulder ball bearings without an inner race ring. These shoulder ball bearings are arranged at a determined mutual spacing from one another within a bearing housing surrounded by a double sleeve. One such sleeve is fixed to the bearing housing and the other sleeve is rigidly connected to the machine frame. An intermediate layer of an elastic material is arranged between these two sleeves. Since of necessity an air gap is present between the bearing housing and the fixed sleeve surrounding such bearing housing, the latter can carry out radial movements. The forces acting upon the bearing can be thus reduced, so that the rotational speed can be increased without impairing the life of the bearings. However, relatively large radial deviations are caused in the state-of-the-art turbine arrangement which can severely impair the process of yarn formation.

The prior art arrangement employing bearings which are elastically supported by means of an intermediate layer additionally results in large radial turbine deviations at critical speeds, complicating the effective sealing of the open side of the turbine with respect to the housing and furthermore impairing the process of yarn formation. Since the bearing housing including the surrounding sleeve constitutes a very large dead mass, there again results undesirably high bearing loads. A further disadvantage with the prior art arrangement resides in the fact that through the use of shoulder ball bearings and due to the unavoidable tolerances as concerns the mutual spacing of the bearings as well as with regard to the spacer sleeve itself, there can occur much too large axial play, causing noise and material fatigue. Another disadvantage exists in terms of the grease lubrication of the ball bearings which is unsuitable at high rotational speeds since dry running can occur, causing premature excessive wear of the cage and eventual destruction of the bearing before the nominal life span of the bearing determined by the fatigue limits has been reached.

Continuing, it should be appreciated that hydrostatic air bearings have already been proposed for OE- spinning rotors. Such type bearings necessitate a supply of compressed air for each of the multitude of spinning rotors arranged on a machine, and this requirement unfavorably influences the price of the machine. Also, the supporting air cushions are extremely thin, i.e., in the range of thousands of a millimeter, so that such bearings are quite susceptible to dust particles carried into the supporting air cushion by the air supply stream, with the result that a source of extremely clean air is necessary.

SUMMARY OF THE INVENTION It is a primary object of the present invention to provide an economically feasible bearing for a spinning rotor permitting of increased upper limits of the rotational speeds in the range of 50,000 to 60,000 rpm. at quiet running conditions, i.e., small radial deviations of the spinning turbine, and possessing a sufficiently low upper critical rotational speed, without detrimentally affecting the long bearing life span.

A further object of the present invention relates to an improved bearing arrangement for a spinning rotor wherein the bearing units can be exchanged with utmost simplicity, thereby enabling a new bearing to be easily mounted once the bearing life span has been reached.

Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, and to eliminate the aforementioned drawbacks and limitations of the prior art proposals, the bearing arrangement for a spinning rotor of an open end spinning device as contemplated by the invention has the spinning rotor incorporating a shaft, at one end of which there is mounted a turbine and at the other end of which there is mounted a drive whorl. Antifriction bearings are provided for supporting the rotor shaft. The exterior of the bearings is rigidly mounted in a sleeve which surrounds the rotor shaft. This sleeve is connected with the walls of a bore in the rotor housing via an elastic member which surrounds such sleeve. Further, the sleeve is a thin-walled light and rigid metallic sleeve member and the elastic member consists of a ring of elastomeric material -which is placed upon the end of the thin-walled light metal sleeve confronting the turbine. This ring provides an airtight seal for the room or compartment between the sleeve and the bore in the housing at the side of the ring facing away from the turbine. Furthermore, there are provided means for permitting the penetration of air into such compartment between the sleeve and the walls of the bore in the rotor housing. Such air penetration means may be constituted by a second elastic outer support member provided for the sleeve at the other end thereof at the drive side in the neighborhood of the drive whorl and/or by the provision of one or a number of open-ended bores or holes at the rotor housing.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

FIG. 1 is a longitudinal sectional view of a bearing arrangement of a spinning rotor designed according to the teachings of the present invention;

FIG. 2 is a cross-sectional view taken substantially along the line Il-ll of FIG. 1;

FIG. 3 is a longitudinal sectional view, similar to the showing of FIG. 1, of a modified construction of bearing arrangement of a spinning rotor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now the drawings, in the various embodiments disclosed herein, and particularly referring for instance to FIGS. 1 and 2, a rotor housing 1 is sealed by a cover 2 containing a fiber supply duct 3 by means of which discrete fibers 4 are transported under the action of an air stream to a fiber collecting surface 5 of a so-called turbine 6 of a rotatable rotor 7. The pressure drop required for transporting the fibers 4 is generated by connecting the rotor housing 1 with a suitable and therefore not particularly illustrated vacuum source through the agency of a duct or conduit 8. Of course, the pressure drop could also be generated by the rotor itself, e.g., by means of radial holes or fan blades provided on the turbine.

The rotor 7 consists of a rotor shaft 9 rotatably supported at the side thereof facing the turbine 6 by a grooved ball bearing 10 determining the axial position. At the other end of the rotor 7 and specifically the rotor shaft 9, there is mounted a drive whorl 11 about which there can be trained a drive belt 12. At the drive side of the arrangement there is mounted a roller bearing 13 which provides a higher static and dynamic load capacity in radial direction, so that the forces transmitted by the drive belt 12 can be easily absorbed. The outer rings or races 13' and 13" of both brearings l0 and 13 are rigidly mounted in a lightweight and rigid aluminum sleeve 14 of small wall thickness.

The thin-walled sleeve 14 itself is supported in a bore 16 of the housing 1 at the region of the grooved ball bearing 10 by means of a relatively small and thin rubber ring 15. This ring 15, formed of elastomeric material, also seals the air so as to suppress the flow of air from the room or compartment 17' between the sleeve 14 and the bore 16 of the housing into the room or compartment 17 surrounding the turbine 6 where there prevails subatmospheric pressure, so that there is not disturbed the air throughput balance of the turbine 6. For the same purpose, the sleeve 14 externally of the grooved ball bearing 10 is provided with a cover member or cover 18 with respect to the room or compartment 17, a small clearance 19 of course being maintained with respect to the rotor shaft 9. By means of this clearance gap 19 the sub-atmospheric pressure which prevails in the room 17 generates a relatively small air current, which is sucked in through holes or apertures 20 in the sleeve 14 from the room or compartment 17 between the sleeve 14 and the bore 16 of the housing 1 while bypassing the bearing. Hence, the pressure on both sides of the grooved ball bearing 10 is thus equalized. By the same token, migration oflubricant from the grooved ball bearing 10 towards the turbine 6 is effectively prevented. This is of particular importance in the case of oil lubricated ball bearings, which at the present time are the only type of antifriction bearings permitting the highest rotational speeds. The rubber or elastomeric ring 15 thus fulfills several important functions in that it maintains the deviation of the rotor within close limits as an elastic member which is placed in the vicinity of the turbine and notwithstanding its softness, and also is used as a means for practically equalizing the pressure at both sides of the grooved ball bearing 10.

Furthermore, the generated airstream flowing through the clearance gap 19, before passing through the holes 20, flows along the rubber ring 15 and the outside of the sleeve 14, cooling both of these components. At the drive side, that is at the side of the sleeve which confronts the drive whorl 11, the sleeve 14 is supported in the bore 16 of the housing by a number of rubber blocks 21 or equivalent elastic support means, and these rubber blocks 21 are uniformly distributed along the circumference of the aforesaid end of the sleeve 14, so that cooling air can penetrate between the sleeve 14 and the bore 16 of the housing 1. The use of a roller bearing 13 at this location exhibits the advantage that the axial play is not determined by this bearing 13, but by the grooved ball bearing 10, and that the unavoidable length tolerances of the bearings, the shaft and of the sleeve 14, cannot influence the axial play of the bearing. Furthermore, the roller bearing 13 has a longer life span and develops less bearing noise if only loaded in radial direction. Due to the cooperation of the two elastic elements, i.e., the ring 15 and the rubber blocks 21 which are mutually spaced as far as possible from one another, it is possible to maintain as small as possible the turbine deviations at the normal operating speeds as well as during predetermined critical speeds and caused by uneven running of the drive belts. This is of great importance for the undisturbed yarn formation process. Since the dead mass, i.e., all elastically supported but non-rotating elements, is kept to a minimum, the bearing load caused by vibrations is reduced and the fatigue limit of the two

bearings

10 and 13 is extended, so that the bearing life span is prolonged. The critical rotational speeds, however, in this arrangement are increased. By suitably varying the characteristics of the elastic members it is possible to carry out adaptation of the critical speeds to practical requirements within certain limits. This adaptation, however, is insufficient for requirements occurring with OE spinning devices, e.g. in case the bobbin change is to be effected at a low speed. In such cases the increase of the mass of the turbine 6, as indicated in FIG. 1 with dash-dotted lines, by an additional weight 22' is recommended. In this manner the lower limit of the range of hypercritical rotational speeds is considerably lowered. The bearing arrangement herein disclosed, and using grease lubrication, can be operated at rotational speeds of up to 45,000 rpm. with a practically acceptable life span. Oil lubrication, which is the only lubrication technique which as a practical matter permits the highest possible rotational speeds, is effected in the following manner:

A nozzle or mouthpiece 23 threadably connected with the housing 1 is connected with a hose 22 which guides a wick 25 extending down into a reservoir 24. An extension 26 of the nozzle 23 penetrates through an opening 27 in the sleeve 14 and the wick 25 releases the oil drop by drop, that is to say, with a metered flow, to the rotating shaft 9, from which location the oil flows to the two bearings and 13. A disk 28, which throws off the oil, prevents the penetration of oil into the turbine room or compartment 17.

In the wick lubrication arrangement the supply quantity of oil is determined by the cross-sectional area of the wick 25 and the elevational difference between the reservoir 24 and the

bearings

10 and 13. The supply quantity of oil can be metered such that it corresponds to the effective requirements. The oil which continues to drip during a standstill period of the machine, however, can overfill the bearings. Thus, suitable precautions must be undertaken to assure that excess oil is thrown out of the bearings as the machine is started up. A further possible variation of oil lubrication system resides in the use of a conventional central lubrication system by means of which, at predetermined timeintervals, a controlled pressure is applied to the supply line by a supply pump supplying the oil to a metering piston, so that the oil quantity drips in selectable steps or stages into the bearing arrangement.

Finally, in FIG. 3 there is disclosed a modified construction of bearing arrangement for a spinning rotor, similar to the showing of FIG. 1, and wherein generally the same reference characters have been employed for the same components. This modified construction of bearing arrangement differs from that shown in FIGS. 1 and 2 in that here there is provided one or a number of air admission holes or bores 30 extending radially through the rotor housing 1 from the outside wall thereof to the inner wall thereof, each such hole or bore 30 being located between the ring and the drive whorl 11. In this case, the rubber blocks 21 at the side of the drive whorl 11 may either extend continuously about the associated end of the sleeve 14 or may be constructed and arranged in the manner previously disclosed with respect to the embodiment of FIGS. 1 and 2, and as best seen by referring to FIG. 2. Each such bore 30 is conveniently covered by a suitable filter 31 so as to filter the incoming air. The bore or bores 30 permit the penetration of air into the room or compartment 17'.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims. Accordingly,

What is claimed is:

1. A bearing arrangement for a spinning rotor of an open end spinning device, comprising a rotor housing, a spinning rotor incorporating a shaft having opposed ends, said shaft being arranged in said rotor housing, a turbine mounted at one end of the shaft, a drive whorl mounted at the other end of said shaft, antifriction bearings for supporting said shaft, a sleeve surrounding said shaft for rigidly mounting the antifriction bearings thereat, said rotor housing have a bore bonded by a wall, an elastic member surrounding said sleeve and connecting said sleeve with the wall of said bore, said sleeve being constituted by a thin-walled light and rigid metallic sleeve, said elastic member comprising a ring of elastomeric material placed upon the end of the thinwalled light metallic sleeve confronting the turbine, said sleeve being spaced from the wall of said bore to define a compartment therebetween, said ring sealing said compartment between said sleeve and the wall of said bore in the housing, and means provided between said ring which seals said compartment and said drive whorl for permitting the penetration of air into said compartment.

2. The bearing arrangement as defined in claim 1, wherein said air penetration means comprises a second elastic outer support member provided for said sleeve at an end thereof defining a drive side which confronts the drive whorl, said second elastic outer support member permitting the penetration of air into said compartment between the sleeve and the wall of the bore in the rotor housing.

3. The bearing arrangement as defined in claim 1, wherein said air penetration means comprise at least one bore provided for said rotor housing for permitting the penetration of air into said compartment between the sleeve and the wall of the bore in the rotor housing.

4. The bearing arrangement as defined in claim 1, wherein the exterior of said antifriction bearings are rigidly mounted at said sleeve.

5. The bearing arrangement as defined in claim I, wherein one of said antifriction bearings comprises a grooved ball bearing and another of said antifriction bearings comprises an axially non-guiding antifriction bearing, said grooved ball bearing being located at the end of the shaft confronting the turbine for rotatably supporting and axially guiding said shaft, the other end of said shaft constituting the drive side of said shaft, said drive side of said shaft being rotatably supported by said axially nonguiding antifriction bearing.

6. The bearing arrangement as defined in claim 5, wherein said axially non-guiding antifriction bearing is a roller bearing.

7. The bearing arrangement as defined in claim 5, wherein said ring of elastomeric material, viewed in axial direction, is arranged externally of the grooved ball bearing, said sleeve having air throughpassage openings located between the grooved ball bearing and the ring of elastomeric material.

8. The bearing arrangement as defined in claim 7, further including a closure provided for the sleeve at the side confronting the turbine, said closure providing a clearance with respect to the rotor shaft, and wherein in the space between the closure and the grooved ball bearing there prevails approximately atmospheric pressure.

9. The bearing arrangement as defined in claim 1, further including an oil drop metering device provided between said antifriction bearings for supplying oil in drops to the rotor shaft.

10. The bearing arrangement as defined in claim 1, further including an additional weight for increasing the mass of said turbine.

11. The bearing arrangement as defined in claim 1, wherein said sleeve is formed of a light metal.

12. The bearing arrangement as defined in claim 11, wherein the light metal of the sleeve is aluminum.

13. The bearing arrangement as defined in claim 1, further including a second elastic outer support member provided for said sleeve at an end thereof defining a drive side which confronts the drive whorl.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,911, 59 DATED October 14, 19 75 INVENTOR(S) IGERHARD MANDL It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Heading, left-hand column, after item [21] insert the following new line:

[30] Foreign Application Priority Data August 17, 1972 Switzerland 12l84/72- Column 5, line 63 "bonded" should read --bounded.

Signed and Sealed this second Day Of March 1976 [SEAL] A ttes t:

Claims

1. A bearing arrangement for a spinning rotor of an open end spinning device, comprising a rotor housing, a spinning rotor incorporating a shaft having opposed ends, said shaft being arranged in said rotor housing, a turbine mounted at one end of the shaft, a drive whorl mounted at the other end of said shaft, antifriction bearings for supporting said shaft, a sleeve surrounding said shaft for rigidly mounting the antifriction bearings thereat, said rotor housing have a bore bonded by a wall, an elastic member surrounding said sleeve and connecting said sleeve with the wall of said bore, said sleeve being constituted by a thin-walled light and rigid metallic sleeve, said elastic member comprising a ring of elastomeric material placed upon the end of the thin-walled light metallic sleeve confronting the turbine, said sleeve being spaced from the wall of said bore to define a compartment therebetween, said ring sealing said compartment between said sleeve and the wall of said bore in the housing, and means provided between said ring which seals said compartment and said drive whorl for permitting the penetration of air into said compartment.

5. The bearing arrangement as defined in claim 1, wherein one of said antifriction bearings comprises a grooved ball bearing and another of said antifriction bearings comprises an axially non-guiding antifriction bearing, said grooved ball bearing being located at the end of the shaft confronting the turbine for rotatably supporting and axially guiding said shaft, the other end of said shaft constituting the drive side of said shaft, said drive side of said shaft being rotatably supported by said axially nonguiding antifriction bearing.