DE10024019A1 - Magnetic bearing assembly for a high speed open-end spinning rotor has a damper with an oscillating body and a roller body and permanent magnet rings with an additional damping ring to give axial and radial support with low friction - Google Patents

Abstract

The magnetic bearing assembly, to give axial and radial support to a high speed open-end spinning rotor, has a damper (9) with a magnetically mounted oscillating body (31), matching the permanent magnet ring (29) at the rotor side. A roller body (32) is between the bearing plate (40) at the stator side and the oscillating body. The magnetic bearing mounting for an open-end spinning rotor has a permanent magnet ring (33) at the oscillating body, with a magnetic bond to the permanent magnet ring at the rotor side. The roller body has a race path (36) at the oscillating body and a race path (37) at the bearing plate, with a roller cage (38) fitted between them with the rollers. The roller race paths are of a material which has a high wear resistance e.g. a ceramic material. The oscillating body is also held in an additional damping medium (35) as a plastics ring with durable elasticity, surrounding the oscillating body. The oscillating body has a limit mounting (34), around the rotor shaft (4) with a small play.

Description

The invention relates to a magnetic bearing according to the Preamble of claim 1.

Most spinning rotors of open-end rotor spinning machines rotate in so-called support disk bearings. Such bearing devices, which have been tried and tested in practice, allow rotor speeds of <100,000 min ^-1 . A disadvantage of such support disc bearings, however, is the not inconsiderable wear on the running surfaces.

That is why they have been different in the past Attempts have been made to open-end spinning rotors Non-contact, that is, wear-free storage.

With a non-contact, for example magnetic or aerostatically mounted rotor with passive radial bearings however, there is a problem that, especially during the run-up phase of the spinning rotor, to undesirable radial Vibrations can come.

There is a risk that the vibrations Can assume magnitude at which the radial deflection of the spinning rotor becomes so high that it damages the Storage is coming.

To avoid such damage, radial Vibration damping systems developed.  

A non-contact rotor can, for example, relate to radial vibration excitation can be actively damped. However, this is a relatively high effort for the Sensors, actuators and control necessary.

Another way to dampen vibrations is to to use passive vibration damping in which an attempt is also made to reduce the radial deflection. Such a device is for example by DE 195 43 745 A1 known.

In this publication, the stator magnet is a magnetic bearing suspended elastically on struts.

In addition, the stator-side magnetic bearing is replaced by a Friction device applied, the correspondingly large Vibration amplitude of the rotor causes damping. The vibration system known from DE 195 43 745 A1 has several disadvantages, however.

A serious disadvantage is, for example, that the Stiffness of the magnetic bearing around the stiffness of the Strut assembly is reduced.

That is, the stator magnet fixing the rotor is not completely local, but attached swingable. At a such an arrangement, the position of the rotor is analogous to that Vibration movements of the stator magnet inconsistent.

The vibration-damping oscillation of the stator magnets can thereby an additional impairment of the rotor smoothness to lead.

Another disadvantage of this known device is in the relatively complex arrangement of the struts to see because Inaccuracies in this area immediately become radial  Offset and / or failure to comply the desired air gap and / or an error related lead to the plane parallelism of the bearing magnets, which the Functionality of the magnetic bearing assembly in question.

To avoid the aforementioned disadvantages, especially for Improving the smooth running of the spinning rotor is therefore one Damping device has been developed, as in the DE 198 19 767 A1 is described.

This known damping device also has one Friction device with friction partners, their friction surfaces be subjected to mechanical loads.

However, this damping device is one of the Friction partner, at least radially, in a fixed position on a stationary one Bearing part arranged. The other friction partner is radial held changeable. The radially changeable Friction partner includes the with a bearing component rotatable shaft of the spinning rotor.

Although with the damping device according to DE 198 19 767 A1 could be ensured in a relatively inexpensive way, that when accelerating the non-contact, passive bearing Spinning rotor to its operating speed, even when driving through its natural vibration frequency ranges, not problems comes through vibrations and also that Smooth running of the spinning rotor could also be improved, also shows this known device has a major disadvantage.

The mechanical friction damper used tends to Frictional jumps, which are primarily due to the different coefficients of friction of adhesion respectively Are due to sliding friction.

Starting from the aforementioned prior art, the Invention, the object of a damping device for a magnetic bearing arrangement of an open-end spinning rotor develop the disadvantages of the known Damping devices does not have.

This object is achieved by a device solved, as described in claim 1.

Advantageous embodiments of the invention are the subject of Subclaims.

The damping device according to the invention has in particular the Advantage that at each rotational frequency of the spinning rotor immediate damping of the rotor body takes place, the Damping strength selectable or defined is adjustable.

That is, that between the rotor-side bearing component and the vibration body effective damping, which among other things the effective force on the reel body and thus on the Vibration body effective magnetic force is dependent can be easily adjusted across the width of the air gap. Since the damping by a roller body, that is, over Rolling friction takes place, there are jumps in the coefficient of friction as they do are inevitable in the known device, reliable avoided.

As described in claim 2, is an advantageous one Embodiment given in particular when Vibration body a permanent magnet ring is set, the  with a permanent magnet ring attached to the rotor corresponds.

The polarity of the two permanent magnet rings is like this chosen that opposing magnetic poles face each other. In this way, a magnetic field is generated that the Vibrating body with a relatively strong, always uniform pressure against the roller body pulls what in Area of the rolling body to a reproducible at any time Roll friction leads.

As set out in claim 3, the reel body is approximately after Kind of an axial deep groove ball bearing formed.

This means that the reel body essentially consists of two outer roller tracks and an intermediate one Variety of roller cage fixation.

One of the two roller tracks is on the vibrating body, the other on a stationary, stator-side bearing plate fixed.

However, the running surfaces of the two roller conveyors have, in Contrary to axial deep groove ball bearings, no rotating Guide groove for the bearing rollers, but are completely flat, so that the rollers fixed in the roller cage on the Above all, roller conveyors can move in the radial direction.

As described in claim 4, there are roller conveyors preferably made of a highly wear-resistant material, for example a technical ceramic material.

The bearing rollers are also freely rotatable in the roller cage can be made of such a ceramic material and then result in an inexpensive, very durable Damping agents.  

Even if the bearing rollers of such a roller body only are made of "normal" ball bearing steel, is the Service life of such a damping agent significantly.

In an alternative embodiment can also be provided be that the vibrating body in addition in another Damping medium is stored (claim 5).

Such a damping medium is then more preferred Embodiment as set out in claim 6, for example a Bearing ring made of a permanently elastic plastic material, the encloses the vibrating body.

Such an elastic damping ring supports the Roll friction of the roller body effectively without Frictional jumps are to be feared.

In a preferred embodiment is on the vibrating body a limit bearing is also provided, which Mechanically entrains vibrating body if due to a Overshoot of the rotor body, the magnetic coupling of the Damping device is overwhelmed.

The limitation bearing described in claim 7 thus represents reliably sure that even unusual vibrations be effectively dampened.

Further details of the invention are as follows exemplary embodiment explained with reference to the drawings removable.

It shows:  

Fig. 1 in side view a schematic representation of a single motor-driven, magnetically supported spinning rotor, with a damping device according to the invention in the area of the rotor cup,

Fig. 2 shows the damping device according to the invention in a larger scale,

Fig. 3 shows the detail X of FIG. 2.

The open-end spinning device shown in FIG. 1 bears the overall reference number 1 .

Such spinning units 1 known per se and described for example in DE 198 19 767 A1 generally have a rotor housing 2 in which the rotor cup 26 of a spinning rotor 3 rotates at high speed.

The spinning rotor 3 is driven by an electromotive individual drive 18 and lies with its rotor shaft 4 in front and rear bearing positions of a magnetic bearing arrangement 5 , which support the spinning rotor 3 both radially and axially.

In addition, an axial catch bearing 6 is preferably additionally provided, against which the rotor shaft 4 can rest when the position regulating device (not shown) of the magnetic bearing arrangement 5 , which is known per se, fails or is switched off.

As usual, the rotor housing 2 , which is open towards the front, is closed during operation by a pivotably mounted cover element 8 , into which a channel plate (not shown) is inserted.

The rotor housing 2 is also connected via a corresponding pneumatic line 10 to a vacuum source 11 , which generates the spinning vacuum required in the rotor housing 2 .

In the cover element 8 or in the channel plate, a channel plate adapter 12 is arranged, which has the thread take-off nozzle 13 and the mouth area of the fiber guide channel 14 . A thread take-off tube 15 connects to the thread take-off nozzle 13 . In addition, an opening roller housing 17 is fixed on the cover element 8 , which is rotatably supported to a limited extent about a pivot axis 16 .

The cover element 8 also has rear-side bearing brackets 19 , 20 for mounting an opening roller 21 or a sliver feed cylinder 22 . The opening roller 21 is driven in the region of its whorl 23 by a circumferential, machine-long tangential belt 24 , while the (not shown) drive of the sliver feed cylinder 22 is preferably carried out via a worm gear arrangement which is connected to a machine-long drive shaft 25 .

In an alternative embodiment, opening roller 21 and / or sliver feed cylinder 22 can of course also be driven in each case via a single drive, for example a stepper motor.

As seen from Fig. 2, at least the magnetic bearing arrangement 5 is arranged a damping device 9 according to the invention in the area of the front bearing assembly 27.

This means that the bearing arrangement 27 arranged in the region of the rotor cup 26 has a stator-side permanent magnet ring 28 , which is surrounded by a current-carrying coil 30 , and a rotor-side permanent magnet ring 29 rotating with the spinning rotor 3 .

The damping device 9 essentially consists of a vibrating body 31 which is magnetically connected to the rotating rotor shaft 4 and a roller body 32 .

In the illustrated embodiment, a permanent magnet ring 33 is fixed on the vibrating body 31 , which corresponds to the rotor-side permanent magnet ring 29 of the front bearing 27 of the magnetic bearing arrangement 5 .

Deviating from the illustrated embodiment, that is, not shown in the drawings, embodiments are also conceivable in which, for example, an additional permanent magnet ring is arranged on the rotor shaft 4 , which acts on a corresponding permanent magnet ring 33 of the vibrating body 31 .

Furthermore, an embodiment is also conceivable which, instead of two corresponding permanent magnet rings, has only one permanent magnet ring 29 , which is preferably arranged on the rotor shaft 4 and is magnetically connected to the vibration body 31 , which is made of a ferromagnetic material.

As can be seen in particular from FIGS. 2 and 3, the vibrating body 31 has a limiting bearing 34 which surrounds the rotor shaft 4 with play.

In an alternative embodiment, as indicated in the drawings, the vibrating body 31 can also be supported in an additional damping medium 35 which is switched on between the stator housing 7 and the vibrating body 31 .

The roller body 32, which is connected between the vibration body 31 and a stationary bearing plate 40 , consists of roller tracks 36 , 37 and a roller cage 38 which fixes a plurality of bearing rollers 39 in a freely rotatable manner.

Fig. 3 shows the roller body 32 and the adjacent components of the damping device 9 in a larger scale.

Function of the facility

During the spinning operation, the spinning rotor 3, which is acted upon by an individual electric motor drive 18, rotates at high speed.

The spinning rotor 3 is supported via its rotor shaft 4 in a contactless magnetic bearing arrangement 5 , which ensures both radial and axial mounting of the spinning rotor 3 during operation.

In order to effectively dampen vibrations of the spinning rotor 3 , in particular while the spinning rotor 3 is running up to its operating speed, a damping device 9 is also arranged in the region of the spinning rotor 3 .

As already indicated above, the damping device 9 consists of a vibrating body 31 which is magnetically connected via a permanent magnet ring 33 to the rotor-side permanent magnet ring 29 of the preferably front bearing point 27 of the magnetic bearing arrangement 5 .

This means that each vibration of the spinning rotor 3 or the rotor shaft 4 is magnetically transmitted via the permanent magnet ring 29 to the permanent magnet ring 33 and thus to the vibration body 31 , which accordingly immediately tries to resonate.

However, the vibrations of the vibrating body 31 are damped by a roller body 32 which is switched on between the vibrating body 31 and the stationary bearing plate 40 . The roller body 32 has roller tracks 36 , 37 which are axially acted upon by the magnetic field of the aforementioned permanent magnet rings 29 , 33 and press on the bearing rollers 39 fixed in the roller cage 38 .

The roller tracks 36 , 37 , which are fixed, for example, by an adhesive connection to the vibrating body 31 or the bearing plate 40 , have flat running surfaces. This means that the bearing rollers 39 are deflected in the radial direction when rotor vibrations occur on the running surfaces of the roller tracks 36 , 37 . The rolling friction occurring when the bearing rollers 39 are shifted leads to an effective damping of the vibration system.

Since the effective rolling friction of the roller body 32 depends, among other things, on the contact pressure of the roller tracks 36 , 37 on the bearing rollers 39 and thus proportionally on the distance of the permanent magnet rings 29 , 33 , the vibration behavior of the damping device 9 according to the invention can be set relatively easily.

If extreme vibrations occur that exceed the magnetic coupling forces of the permanent magnet bearing rings 29 , 33 , the rotor shaft 4 runs against the mechanical limiting bearing 34 , which consists, for example, of a brass bushing, and mechanically displaces the vibrating body 31 in the radial direction.

In an alternative embodiment, the vibrating body 31 can additionally be surrounded by a further damping medium, for example a bearing ring 35 made of permanently elastic plastic.

Such a permanently elastic plastic bearing ring 35 supports the rolling friction of the roller body 32 .

This means that if necessary 35 rotor vibrations can be damped even more effectively by using such a permanently elastic plastic bearing ring.

The invention is not limited to that described above in US Pat Drawings illustrated embodiment limited.

Within the scope of the invention, there are definitely others Design variants conceivable without the general inventive idea is left.

It is conceivable, for example, 9 both, as described above, to install in the area of the front bearing 27 and additionally provide the damping device according to the invention a corresponding damping means 9 in the region of the rear bearing of the magnetic bearing assembly. 5

Claims (7)

1. Magnetic bearing arrangement for the axial and radial support of a spinning rotor rotating at high speed, each with permanent magnet rings on the rotor and stator side and a damping device for influencing radial rotor vibrations, characterized in that the damping device ( 9 ) has a magnetically mounted vibrating body ( 31 ) with corresponds to a rotor-side bearing component ( 29 ), a roller body ( 32 ) being switched on between the vibration body ( 31 ) and a stator-side bearing plate ( 40 ). 2. Magnetic bearing arrangement according to claim 1, characterized in that a permanent magnet ring ( 33 ) is fixed to the vibrating body ( 31 ) and is magnetically connected to a permanent magnet ring ( 29 ) installed on the rotor side. 3. Magnetic bearing arrangement according to claim 1, characterized in that the roller body ( 32 ) from a vibrating body ( 31 ) arranged roller conveyor ( 36 ), a on the bearing plate ( 40 ) fixed roller conveyor ( 37 ) and an intermediate roller cage ( 38 ) with Bearing rollers ( 39 ). 4. Magnetic bearing arrangement according to claim 3, characterized in that the roller tracks ( 36 , 37 ) consist of a highly wear-resistant material, preferably a ceramic material. 5. Magnetic bearing arrangement according to claim 1, characterized in that the vibration body ( 31 ) is additionally mounted in a further damping medium ( 35 ). 6. Magnetic bearing arrangement according to claim 5, characterized in that a permanently elastic plastic bearing ring ( 35 ) is provided as an additional damping medium, which comprises the vibration body ( 31 ). 7. Magnetic bearing arrangement according to claim 1, characterized in that the vibration body ( 31 ) has a limit bearing ( 34 ) which comprises a rotor shaft ( 4 ) of the spinning rotor ( 3 ) with little play.