WO2012059535A1

WO2012059535A1 - Rolling-element bearing having a direct drive

Info

Publication number: WO2012059535A1
Application number: PCT/EP2011/069299
Authority: WO
Inventors: Günter Schmid; Wolfgang Heinrich; Ralf SCHÜLER; Christoph Frank
Original assignee: Schaeffler Technologies AG & Co. KG; Ina Drives & Mechatronics Gmbh & Co. Ohg
Priority date: 2010-11-06
Filing date: 2011-11-03
Publication date: 2012-05-10
Also published as: DE102010050707A1

Abstract

The invention relates to a rolling-element bearing having a direct drive unit and to a bearing ring of a rolling-element bearing. The rolling-element bearing comprises a stationary bearing ring (01) which is connected to at least one primary part (07) of the direct drive unit, a bearing ring (02) that is designed as a secondary part and that can be rotated relative to the stationary bearing ring (01), and rolling elements (04), which are arranged between the stationary bearing ring and the rotating bearing ring. According to the invention, the rotatable bearing ring (02) is provided with rotor poles (06). The primary part comprises a stator winding (10) and covers the rotor poles (06) of the rotating bearing ring (02) at least in some sections.

Description

Name of the invention

Rolling bearings with a direct drive

The invention relates to a roller bearing with a direct drive according to the preamble of claim 1.

Generic rolling bearings include a fixed bearing ring, a rotatable bearing ring, and arranged therebetween rolling elements. The stationary bearing ring is connected to a primary part of a drive unit, while the rotatable bearing ring forms a secondary part.

Typical applications of the invention are machines, machines and systems in which materials, parts, assemblies, equipment or the like are conveyed on a circular path, or frame or racks must be positioned. These include rotary, clocked assembly and testing machines, continuously operated interlinking, handling systems, robot applications, water jet and laser cutting systems, medical diagnostic equipment, beverage filling systems, wind turbines and packaging machines.

From WO 2008/022737 a sektionaier drive a turntable for a bottling plant is known. The rotatable machine part carries a ring with regularly placed electric or permanent magnets. The wreath opposite a stator is arranged on the stationary machine part. The stator is constructed in the manner of a linear drive and bent so that it covers a sector of the ring. In the case of very large turntables, the permanent magnets on the rotatable machine part represent a considerable danger potential for the assembly and operating personnel. In addition, a very large number of permanent magnets is required, which makes the drive enormously expensive in comparison to the servo drive. From the state of the art so-called torque motors are known as rotary direct drives. These are usually liquid-cooled, high-pole permanent-magnet three-phase synchronous motors, which are used particularly frequently for rotary indexing machines, rotary tables, swivel axes, rotary axes, turret switching and drum switching in single and multi-spindle machines, dynamic tool magazines and turning spindles in milling machines. The rotor is equipped with permanent magnets. For a complete drive unit, a bearing and an encoder system are additionally required. The connection with the rotating machine part and the storage is very expensive for very large diameters of the driven machine parts.

EP 1 485 980 B1 shows a torque motor with a segmented stator, wherein each of the stator segments is independently operable and the motor can also be operated with a single stator segment. The rotor carries the permanent magnets. For very large rotor diameters, many magnets are needed, making the rotor expensive and heavy.

From DE 10 2004 045 992 A1 a permanently excited electrical machine is known, in which the permanent magnets (excitation) and the stator winding are arranged on the primary part, while the secondary part (rotor) has only pronounced poles for guiding the magnetic flux. The publication deals primarily with linear drives. There is no statement for the storage of the secondary part.

In addition, bearings of smaller design with an integrated motor or generator are known in which usually permanent magnets are arranged on the rotating bearing ring, while the stationary bearing ring is the stator with stator windings.

The object of the invention is to provide a rotary direct drive, the cost also for very large systems (diameter of the Rotors larger than 1 m) can be used and in which a risk potential for operating personnel is minimized by large magnetic fields on moving parts. An important aspect in this case are the rotary bearing and the electric drive of the rotating machine head, the bearing should support the axial weight load of the machine head and the centering thereof, while the drive provide a continuous or clocked movement and the required torque angle synchronously with adjacent machine parts should. The object is achieved by a roller bearing with the features of claim 1.

An inventive rolling bearing initially comprises in a known manner a fixed and a rotatable bearing ring, between which rolling elements are arranged. The fixed bearing ring is rotatably connected to a primary part of a direct drive. The primary part preferably comprises a laminated core with a stator winding. The solution of the problem is achieved in that the rotatable bearing ring is formed as a secondary part, that on a primary surface facing the surface of pronounced magnetizable rotor poles and grooves are provided which are integrally formed with the bearing ring. The pronounced rotor poles are arranged directly opposite the primary part.

The rotor poles can preferably be incorporated directly into the production of the massive bearing ring in these, by machining or non-cutting process. The rotor poles are in this case formed integrally with the bearing ring.

But it is also possible, for example, to attach a laminated core with the rotor poles on the bearing ring. In this case, eddy current losses can be kept small. In a first preferred embodiment of the invention, the rotatable bearing ring is the outer ring of the rolling bearing, wherein the salient rotor poles extend in the radial direction to the outside, wherein the primary part encloses the outer surface of the outer ring at least in sections.

In another embodiment, the inner ring is rotatable and the outer ring fixed. Here, the salient rotor poles are disposed on the inner surface of the rotatable inner ring extending inward in a radial direction while the primary parts are disposed inside the inner ring.

In a further embodiment, the pronounced rotor poles extend in the axial direction, that is to say they are formed, for example, on the end face of the rotatable bearing ring directed downwards (or above, for example, for suspended mounting devices). The primary parts are arranged correspondingly below (or above) the rotatable bearing ring. An advantage of this embodiment is that the rotatable bearing ring is freely accessible over its entire circumference. Another advantage is seen in that the poles of the stator and rotor are flat on the opposite surfaces, which simplifies manufacturing and thus minimizes manufacturing costs.

The direct drive can be designed as a synchronous machine or reluctance machine.

In the synchronous machine, the primary part comprises a stator winding and an exciter circuit. The excitation circuit is preferably formed by permanent magnets, but may also be an electrical field winding. The excitation circuit is not provided on the secondary part in this variant, but integrated into the primary part. Due to the displacement of the excitation in the primary part, a much smaller number of magnets is required when using permanent magnets than would be the case with magnets in the secondary part. In addition, magnets are no longer moved when rotating machine part, so that the risk potential significantly reduced becomes. The weight saving on the moving machine part is also a decisive factor.

In the case of the reluctance machine (preferably switched-reluctance motor SRM), the primary part comprises only the stator winding, which is driven in a known manner according to the motor type. In this case, either diametrically opposite or adjacent stator windings can be used to form the magnetic poles. Advantageously, a rotor position detection is provided which operates preferably inductively or magnetoresistively. The rotor position detection is used for the correct control of the drive, preferably by means of a power converter. In a preferred embodiment, the rotor position detection is based on the counting of the passing rotor poles.

The expert can make the dimensioning of the electrical machine or the primary part and its control depending on the choice of engine type, so that in this respect detailed explanations are omitted. The advantages of the invention are to be seen in particular in the fact that a direct drive for very large diameters can be integrated directly into a bearing, while the rotating bearing ring, which simultaneously forms the secondary part, can be produced simply and inexpensively. The embodiments described below relate to the realization of a synchronous machine with permanent excitation, wherein the permanent excitation is shifted in the stator.

Under very large diameters are here Wälzkreisdurchmesser the bearing of about one to five meters to understand. The ring height of such bearings is preferably about 25 to 400 mm. The tooth period of the poles is preferably about 10 to 50 mm, while the number of poles on the rotatable Bearing ring up to 1600 at the largest possible diameter. It is a tangentially acting electromagnetic motor force density in the rated operation of about 1 to 2 N / cm ² and achieved in peak operation of about 4 to 6 N / cm ² . A preferred embodiment variant of the invention is shown in the figures. Show it:

1: a schematic representation of a rolling bearing with direct drive as a synchronous motor with permanent excitation in the primary part in cross-section and in a plan view;

2 shows a detailed representation of the drive components of the rolling bearing shown in FIG. 1.

Fig. 1 shows an inventive rolling bearing with an inner ring 01 as a fixed bearing ring and an outer ring 02 as a rotatable bearing ring. The outer ring 02 is rotatable about a rotation axis 03. Between inner ring 01 and outer ring 02 rolling elements 04 are arranged in a known manner. A Wälzteilkreisdurchmesser D is greater than 800 millimeters and is preferably in the range of about 1 to 5 meters.

The rolling bearing exemplified in Fig. 1 is a four-point ball bearing, which is also referred to as a rotary joint or ball slewing connection. Of course, the invention can also be applied to other types of bearings, such as double-row angular contact ball bearings in O or X arrangement, radial-axial cylindrical roller bearings, cross-bearings or other bearings in preloaded design. The outer ring 02 is preferably connected at its upper side to the machine part (not shown), which performs the transport or conveying function. takes. The outer ring 02 is provided in the radial direction on the outside with pronounced rotor poles 06, which are distributed uniformly around the circumference of the outer ring 02. Thus, the outer ring 02 forms a secondary part of an electrical machine.

With the inner ring 01 at least two primary parts 07 are connected via a base plate 08, which surround the secondary part or the outer ring 02 in sections. The primary parts 07 comprise stator teeth 09 with stator windings 10 and permanent magnets 11 and interact with the rotatable outer ring 02 according to the electromechanical operating principle as a direct drive (see FIG. 2). The arrangement of the permanent magnets 1 1 can also be done at another suitable location in the laminated core.

The person skilled in the principles of the structure of a direct drive familiar and he can adapt to the geometric and electrical conditions.

Since the primary parts 07 and the outer ring 02 attract magnetically, they are arranged relative to one another such that the magnetic attraction forces compensate each other and thus do not cause any additional bearing load. In the case of two primary parts 07, these are arranged diametrically opposite the axis of rotation 03, offset by 120 ° relative to one another in the case of three primary parts, etc.

The size of the tangentially acting engine torque also depends, among other things, on the active air gap area. That is, the longer and higher the primary parts 07, the greater the driving force of the motor. A height h of the primary part 07 must of course be matched to the height of the outer ring 02. At a suitable location between the primary parts 07 or integrated into this, a scanning head 12 is provided, preferably connected to the base plate 08 in a suitable width, by means of which the poles of the outer ring 06th be scanned. Thus, the relative and / or absolute angular position of the outer ring 06, and optionally the speed can be determined.

In interaction with a position control loop, the control of the stator coils 10 of the primary parts 07 takes place depending on the drive design in a known manner to regulate the position of the outer ring 02. The angle measuring system can be based on the inductive or magnetoresistive operating principle, both of which are robust against external environmental influences and thus work reliably.

Fig. 2 shows a detailed view of the primary part 07 and the outer ring 02 in the range of a few poles 06 and stator teeth 09. The periods of primary part 07 and outer ring 02 are only slightly different from each other, in such a way that the number of stator teeth 09 in the primary part differ from the number of poles 06 in the outer ring 02 by integers, for example, by 1, 2 or more. In any case, none of the numbers is a multiple of the other pole or number of teeth. The difference between the number of poles is in any case smaller than the total number of poles of primary part or secondary part. The grooves 13 between the poles 06 of the outer ring 02 can be cast here and also in all embodiments with a Kunststoffvergussmasse or the like, so that the risk of contamination is low and the maintenance and cleaning is facilitated. The primary part 07 is preferably formed from a laminated core. The windings 10 are inserted pre-wound in grooves between the stator teeth 09 or wrapped directly in these. The windings 10 are preferably designed in three phases. There are also other motor structures are known in which, for example, the stator teeth 09 are made separately with the windings and then on Stator be attached. Of course, the stator teeth may also be provided with pole shoes in order to optimize the magnetic flux.

The permanent magnets 1 1 are introduced at a suitable location in the laminated core, so that an excitation circuit is formed, which allows magnetic excitation of the secondary part and an overlay with the magnetic fields of the stator coils is possible.

LIST OF REFERENCE NUMBERS

01 - inner ring

02- outer ring

03- rotation axis

04 rolling elements

05-

06- Pol

07 - primary part

08- base plate

09- stator tooth

10 winding

11 - permanent magnet

12-scanning head

13- grooves between poles

Claims

claims

1 . Rolling bearing with a direct drive unit comprising:

- A stationary bearing ring (01) which is connected to at least one primary part (07) of the direct drive unit;

- A trained as a secondary part relative to the stationary bearing ring (01) rotatable bearing ring (02);

- Rolling elements (04) which are arranged between the stationary and the rotating bearing ring;

characterized in that

- The rotating bearing ring (02) is provided with pronounced magnetizable rotor poles (06) which are formed integrally with the bearing ring; and that

- The primary part comprises a stator winding (10) and at least partially covers the rotor poles (06) of the rotating bearing ring (02).

2. Rolling bearing according to claim 1, characterized in that the primary part (07) comprises an exciter circuit.

3. Rolling bearing according to claim 1 or 2, characterized in that the exciter circuit by permanent magnets (1 1) is formed.

4. Rolling bearing according to one of claims 1 to 3, characterized in that it has a Wälzteilkreisdurchmesser (D) which is equal to or greater than 800 mm.

5. Rolling bearing according to one of claims 1 to 4, characterized in that two or more primary parts (07) are provided, which are arranged distributed on the circumference of the rotatable bearing ring (02).

6. Rolling bearing according to one of claims 1 to 5, characterized in that the stator winding (10) is arranged on stator poles (09), wherein the number of stator poles (09) is not equal to the number of rotor poles (06), wherein the number differs only by integer poles and the difference is smaller than the total number of poles of the primary part or the secondary part.

7. Rolling bearing according to one of claims 1 to 6, characterized in that the pronounced rotor poles (06) extend in the radial or axial direction.

8. Rolling bearing according to claim 6, characterized in that the rotating bearing ring (02) is an outer ring (02) and the salient rotor poles (06) extend in the radial direction to the outside, wherein the primary part, the outer surface of the outer ring (02) at least partially encloses.

9. Rolling bearing according to one of claims 1 to 8, characterized in that the number of rotor poles (06) is 310 to 1600.

10. Rolling bearing according to one of claims 1 to 9, characterized in that the pole pitch of the rotor poles is about 10 to 50 mm.