WO2010028633A1

WO2010028633A1 - Multi-row large-diameter rolling bearing having multi-part outer ring

Info

Publication number: WO2010028633A1
Application number: PCT/DE2009/001260
Authority: WO
Inventors: Rudolf Zeidlhack
Original assignee: Schaeffler Kg
Priority date: 2008-09-10
Filing date: 2009-09-05
Publication date: 2010-03-18
Also published as: DE102008046623A1

Abstract

The invention relates to a multi-row large-diameter rolling bearing, comprising at least two bearing rows, the large-diameter rolling bearing comprising an outer ring which is common to all bearing rows and includes at least three ring elements (2, 3, 4), wherein at least one first ring element (2), which is intended for the connection to a connecting design, is made of unhardened steel and at least one second and a third ring element (3, 4), each of which forms at least one raceway (7) for rolling bodies (8), are made of hardened steel.

Description

Name of the invention

Multi-row slewing bearing with multi-part outer ring

description

Field of the invention

The invention relates to a multi-row slewing bearing. Such rolling bearings are used, for example, in rotor main bearings of wind turbines or in main bearings of tunnel boring machines.

Object of the invention

Rolling bearings are usually referred to as slewing bearings whose outer diameter exceeds a range of about 800 mm to 1000 mm. Large rolling bearings, which are used in wind turbines as a rotor bearing to rotatably support a rotor relative to a housing, may have an outer diameter of for example 3000 mm. It is true that with increasing bearing pitch circle more rolling elements can be used, so that the bearing capacity increases. Due to constantly increasing performance of wind turbines and associated larger dimensions of these systems, also increase the forces and moments to be absorbed by the rotor bearing. Basically, this requirement is met with a larger bearing pitch circle and / or with an increase in the number of bearing rows.

However, it proves difficult to find a suitable material or a suitable manufacturing process for the bearing rings, so that the finished bearing ring meets the requirements resulting from the high forces and moments. On the one hand, a high hardness of the raceways is required by the bearing ring in order to be able to absorb the forces transmitted by rolling elements over the required service life. On the other hand, the bearing ring, in particular the outer ring, must also have a certain core toughness, since this also has a component function, namely borrowing during operation tilting moments of the two rows of bearings and thus to the stability of the adjacent construction, e.g. a housing, contribute. Too rough outer ring would greatly increase the risk of cracking or crack propagation.

If the outer ring is made of tempered steel, the result is a cost-effective production and the outer ring has a high toughness, but the hardness of the outer ring is very low. Also, by means of a heat treatment, for example inductive surface hardening of the raceways, ultimately reduced load capacity and thus reduced service life must be expected. In particular, the fatigue life of the hardening layer is low. In addition, since a relatively deep Randhärteschicht is required due to the high forces to be absorbed, also create manufacturing problems, making the production in turn is more expensive. When hardened bearing steel is used, sufficient hardness of the raceways is achieved. However, the outer ring no longer has the required toughness and there are much higher production costs. Due to the heat treatment, the dimensional stability of the outer ring, eg compliance with positional tolerances for bores for attachment to the adjacent construction, can be decisively worsened.

Although the above-mentioned requirements with regard to hardness and toughness on the outer ring can be fulfilled in principle by using hardened steel, the outer ring is hardened to the surface. However, this results in high production costs, since the required manufacturing steps (carburizing, annealing, curing, tempering) are time consuming and costly. The use of case-hardening steel continues to present risks through the heat treatment process, since high stresses can occur in the material and render the workpiece unusable. Critical is especially the phase after carburizing. It is true that the larger the inner circle diameter of the cross-sectional profile of the rings to be hardened, the greater the risk of cracking. However, the size of the cross-sectional profile is determined by design specifications, e.g. Number of bearing rows and thus raceways on a ring or required, minimum area moment of inertia, given.

The production of large outer rings for corresponding bearings is therefore either very expensive, costly and fraught with risks (surface hardening of case hardened steel), associated with reduced life (surface hardening of tempered steel) or characterized by an expensive and dimensional stability negatively affecting heat treatment (hardened bearing steel). The use of multi-part outer or inner rings is already known. Thus, DE 10 2005 019 481 A1 discloses a tapered roller bearing whose outer ring and inner ring each consist of two parts, wherein in each case a part of the rings is formed by a raceway ring for the start of the tapered rollers. This raceway ring should be held by a support ring. By means of these separate raceway elements, a very light bearing with low production costs is to be created, in particular with relatively small demands on the male load and / or precision of the bearing. The support ring is therefore made of plastic, light metal or sintered metal. The tapered roller bearing of DE 10 2005 019 481 A1 can only absorb radial forces and axial forces in one direction.

Object of the invention

The invention has for its object to provide a multi-row slewing bearing, which in addition to the necessary hardness of the raceway surfaces also has the required toughness for an outer ring, and which are made at the same time simple, relatively inexpensive and safe.

Summary of the invention

This object is achieved according to the invention by a multi-row slewing bearing with at least two rows of bearings, the slewing bearing comprising a common outer ring for all bearing rows, comprising at least three ring elements, wherein at least a first ring element, which is provided for connection to a connecting structure, from hardened steel and at least a second and a third ring member, which forms at least one raceway for rolling elements, in each case made of hardened steel. The invention is based on the finding that by separating the outer ring into elements which assume the component function of the outer ring, ie the absorption of tilting moments, and elements which form raceways for rolling elements, the outer ring as a whole optimally fulfills the above-mentioned requirements can fulfill. The various elements can be optimized specifically for their respective function, for example with regard to the selection of materials and / or with regard to production. In particular, materials with different properties in terms of hardness and toughness can be used selectively, so that the respective advantages of the materials can be optimally utilized.

According to the invention, the second and third ring element of the outer ring should form raceways for the rolling elements and therefore preferably has the corresponding material properties. For example, hardened steel should be used here according to the invention. Due to the ability to use now cross-sectional profiles with a much smaller area, in particular smaller Innkreisdurchmesser, the curing of these ring elements is much easier and safer. In contrast, the first ring element has no track and according to the invention should take on the component function of the outer ring, which in turn is preferably associated with a corresponding material property. Uncured steel is best suited for this because it has the necessary toughness.

Although the details of the invention are described below with reference to a purely three-part outer ring. Of course, outer rings with more than three ring elements are also conceivable. Thus, it is possible in addition to the first ring element, which has the component function of the outer ring so the ability to absorb tilting moments, more than two ring elements with raceways. Of course, it is also possible to use a plurality of ring elements with a component function instead of a single first ring element with a component function, each of which has no track. According to one embodiment, the first ring element consists of unhardened tempering steel. As a result, the first ring element has a high degree of toughness and can thus optimally fulfill the component function of the outer ring.

According to one embodiment, the second and the third ring element consists of hardened hardened steel or hardened bearing steel. In one embodiment, the hardness of the second and third ring members is at least 58 HRC. It has been found that these degrees of hardness can be achieved without difficulty even in large rolling bearings, if a division of the outer ring function according to the invention takes place on the different ring elements, i. e.g. only the second and third ring element is hardened accordingly, whereby the cross section to be hardened is correspondingly smaller.

According to one embodiment, the first ring element has at least one passage and / or a threaded bore for attachment to the adjacent construction. According to one embodiment, the at least one bore extends in the axial direction of the large rolling bearing, i. parallel to a bearing axis of the slewing bearing. Furthermore, a plurality of bores is preferably distributed circumferentially over the first ring element. The outer ring can thereby be e.g. be secured by screws in a machine house. Alternatively or additionally, the outer ring can also be held axially, for example, by a corresponding shoulder in a connecting construction and pressed against the shoulder by a further element from the axially opposite side.

According to one embodiment, the first ring element is connected to the second or to the third ring element by an interference fit, connecting elements and / or by gluing. Decisive in the first place is a safeguard against falling out of the second and third ring elements, for example during transport or assembly of the slewing bearing. A suppression of a rotation of the ring elements to each other during operation is not mandatory, but is desirable. In double-row tapered roller bearings in O arrangement, a backup against axial displacement during operation is usually not necessary, since the forces transmitted by the tapered rollers counteract this. As mechanical fasteners come in addition to corresponding lugs, projections, grooves, etc. also welds into consideration.

According to one embodiment, the first ring element has a cylindrical outer contour. Preferably, this cylindrical outer contour extends over the entire axial extent of the first ring element or the outer ring and always has the same outer diameter. The cylindrical outer contour can serve for support in a connecting construction. The first ring element is not unnecessarily weakened and can fulfill the component function optimally.

According to one embodiment, the first ring element terminates axially flush with the second and third ring element. The first ring element does not extend axially any further than the second or third ring element lying axially outwards in each case. The axial ends of the outer ring are thus formed on one side by the first ring member and the second ring member and on the other side by the first ring member and the third ring member. A precisely flush axial termination of two ring elements is not required, but rather should serve according to the invention, the first ring member on the one hand for supporting the second and third ring member and on the other hand, however, do not extend unnecessarily far.

According to one embodiment, the first ring element forms a radial guide for the second and the third ring element. The first ring element thus represents a radial stop for the further ring elements. In particular, radially directed forces directed outward from the second and the third ring element can be absorbed by the radial guidance of the first ring element. These radial forces result from the through the Rolling elements transmitted to the second and the third ring member forces. The second, the third ring element and optionally the other ring elements with raceways thus have a smaller outer diameter than the first ring element. According to one embodiment, an axially extending contact surface between the first ring element and the second ring element or between the first ring element and the third ring element is formed by a respective cylinder jacket surface arranged coaxially to a bearing axis. In a three-part outer ring thus at least two separate radial contact surfaces can form, each having the shape of a cylinder jacket surface. Each axially extending contact surface is formed by at least one cylindrical and coaxial to the bearing axis of the large rolling bearing surface.

According to one embodiment, the first ring element forms an axial guide in each case in an axial direction for the second and the third ring element. The first ring element thus represents an axial stop for the other ring elements. In particular axial forces directed from the second and the third ring element can be absorbed by the axial guidance of the first ring element towards the bearing center; optionally also from other ring elements with raceways. These axial forces result from the transmitted through the rolling elements on the second and the third ring member forces. According to one embodiment, a radially extending contact surface between the first ring element and the second ring element or between the first ring element and the third ring element is formed by a respective annular surface arranged perpendicular to a bearing axis. In a three-part outer ring thus resulting in at least two separate annular surfaces. Over these contact surfaces forces can be transmitted between the ring elements. The radially extending contact surface thereby extends in at least one plane perpendicular to the axis of rotation of the large rolling bearing. Preferably, the radially extending contact surface extends in the radial direction at least over the radial extent of the raceway of this ring element and the axially extending contact surface extends in the axial direction at least over the axial extent of the raceway of this ring element. The second and third ring elements are in contact via the contact surfaces with the first ring element. This extension of the contact surfaces ensures that the high forces introduced via the rolling elements, for example tapered rollers, can be conducted via the second or third ring element into the first ring element such that a displacement of the second or third ring element is prevented , At the same time, a corresponding cross section of the second and third ring element, whereby a certain stability of the second and third ring element is ensured.

According to one embodiment, the first ring element has a substantially T-shaped cross-sectional profile. In this case, the first ring element preferably also has an outer contour in the form of a cylinder jacket surface, so that the first ring element is mirror-symmetrical with respect to a plane extending perpendicular to its axis of rotation. According to one embodiment, the second and the third ring element has a substantially triangular cross-sectional profile. The legs and the opening angle of this triangular cross-sectional profile are preferably selected such that it is tuned to the T-shaped cross-sectional profile of the first ring element. Thus, the triangular cross-section preferably represents a right-angled triangle whose base forms the raceway, while the legs form the contact surfaces with the first ring element.

According to one embodiment, the second and the third ring element consist of a substantially strip-shaped element. These ring elements are thus formed by a sheet-like ring. This can for example have a frustoconical outer contour. According to one embodiment, the slewing bearing has two rows of bearings. In particular, these two rows of bearings form a double row tapered roller bearing. Preferably, the two rows of bearings of the double-row tapered roller bearing form an O-arrangement.

According to one embodiment, rolling elements roll between the second ring element and a first inner ring and between the third ring element and a second inner ring, wherein the inner rings can be arranged directly on a shaft. Since there are two separate inner rings whose cross-sectional profiles are consequently smaller than the cross-sectional profile of a single inner ring, there are no particular problems with respect to production. The first and second inner rings can therefore be made in a conventional manner, preferably these inner rings are made of hardened steel, e.g. Hardened case hardened steel or hardened bearing steel. Preferably, the first and the second inner ring are axially spaced by an intermediate ring.

According to one embodiment, at least one ring element of the outer ring has been produced by machining. On the one hand, high demands on the accuracy, e.g. On the other hand, it is a safe method of production. Preferably, all ring elements of the outer ring were made by machining.

According to one embodiment, the at least two bearing rows can absorb axial forces, radial forces and tilting moments. In particular, axial forces can be absorbed in both directions. The multi-row slewing bearing can thus be used in the context of a so-called Einlager concept. In order to enable a more compact design, the bearing of the rotor shaft in wind turbines or the main bearing in tunnel boring machines is often designed as a storage concept. In contrast to conventional two-point or three-point supports with two or three separate bearing points, when loading ger concept, a single bearing both all axial and radial forces and tilting moments on. This single bearing consists for example of two employed tapered roller bearings or two employed tapered roller rows. The advantages according to the invention are particularly effective here, since the cross-sectional profile of outer rings in the case of insert concepts has a necessarily complex shape due to the at least two raceways. The production is therefore particularly difficult here and possibilities to make the manufacturing process safer, cheaper and easier are of particular importance.

According to one embodiment, the large roller bearing is used as a rotor main bearing a wind turbine. Here again, it may be in the context of a Einlager concept, i. be used with a relatively complex outer ring cross section. Basically, the complex and sometimes massive cross-sectional shape of the outer rings in Rotorhauptlagerungen but also based on the fact that the outer ring is not necessarily completely supported over its axial extent on its outer circumferential surface. The force flow within the outer ring from each raceway to the area of the outer jacket surface, which is supported by a connection construction, is particularly strong here.

However, the large antifriction bearing according to the invention can also be used in other areas in which the benefits of the invention come into play. Thus, the large-diameter rolling bearing according to the invention can e.g. be used as the main storage of a tunnel boring machine.

Brief description of the drawings

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Hereby show: 1 is a schematic representation of a double-row tapered roller bearing according to a first embodiment,

FIG. 2 shows a schematic representation of an outer ring according to the invention according to a second embodiment, and FIG

Fig. 3 is a schematic representation of an outer ring according to the invention according to a third embodiment.

Detailed description of the drawing

Fig. 1 shows a double-row tapered roller bearing 1. Shown is the first ring member 2 with T-shaped cross-section, which is connected to the second ring member 3 and the third ring member 4. The contact takes place via axial contact surfaces 5a and 5b of the first and second ring element 2, 3 and via radial contact surfaces 6a and 6b of the first and second ring element 2, 3. The first and second ring elements 2, 3 also form raceways 7 for tapered rollers 8 and have a triangular cross section. The tapered rollers 8 are further guided by inner rings 9a and 9b, which are axially spaced by an intermediate ring 10 from each other. There is an O arrangement of the two rows of bearings.

At the edges 12, an undercut or a radius in the first ring member 2 may be provided to avoid stress cracks. Accordingly, the second ring element 3 and the third ring element 4 have a radius at this point.

The first ring element 2 has a plurality of bores 11, which are distributed circumferentially, and by means of which the first ring element 2 can be attached to a connecting construction, not shown. The axial contact surfaces 5a and 5b in this case form an annular surface which extends in the radial direction along the entire radial extent of the raceway. The radial contact surfaces 6a and 6b form a cylindrical surface extending in the axial direction along the entire axial extent of the respective raceway.

Fig. 2 shows schematically an outer ring consisting of a first ring member 2 with T-shaped cross-section, which is in contact with a second ring member 3 and a third ring member 4. The axial contact surfaces 5a, 5b of the second and third ring member 3, 4 are made in In this case, two annular surfaces whose common axis of rotation is the axis of rotation R of the large roller bearing. Accordingly, the radial contact surfaces 6a, 6b of the second and third ring elements 3, 4 consist of two cylindrical surfaces arranged concentrically about the axis of rotation R.

3 schematically shows an outer ring consisting of a first ring element 2, which is in contact with a second ring element 3 and a third ring element 4. The second and third ring element in this case consists of a strip-shaped element which axially into corresponding recesses of the first ring element. 2 is fitted.

LIST OF REFERENCE NUMBERS

1 double row tapered roller bearing

2 first ring element 3 second ring element

4 third ring element

5a, 5b axial contact surfaces

6a, 6b radial contact surfaces

7 raceways 8 tapered rollers

9a, 9b inner rings

10 intermediate piece

11 bore

12 edge

Claims

claims

1. Multi-row slewing bearings, with at least two rows of bearings, the large rolling bearing comprising a common for all bearing rows outer ring consisting of at least three ring elements (2, 3, 4), wherein at least a first ring element (2), which is provided for connection to a connecting structure is made of unhardened steel and at least a second and a third ring member (3, 4), each of which forms at least one raceway (7) for Wälz- body (8) made of hardened steel.

2. Multi-row slewing bearing according to claim 1, characterized in that the first ring element (2) consists of unhardened tempering steel.

3. Multi-row slewing bearing according to one of the preceding claims, characterized in that the second and the third ring element (3, 4) consists of hardened hardened steel or hardened bearing steel.

4. Multi-row slewing bearing according to one of the preceding claims, characterized in that the first ring element (2) has at least one passage and / or at least one threaded bore (11) for attachment to the adjacent construction.

5. Multi-row slewing bearing according to one of the preceding claims, characterized in that the first ring element (2) is connected to the second or to the third ring element (3, 4) by an interference fit, connecting elements and / or by gluing.

6. Multi-row slewing bearing according to one of the preceding claims, characterized in that the first ring element (2) has a cylindrical outer contour.

7. Multi-row slewing bearing according to one of the preceding claims, characterized in that the first ring element (2) is axially flush with the second and third ring element (3, 4).

8. Multi-row slewing bearing according to one of the preceding claims, characterized in that the first ring element (2) forms a radial guide for the second and the third ring element (3, 4).

9. Multi-row slewing bearing according to one of the preceding claims, characterized in that an axially extending contact surface (6a, 6b) between the first ring element (2) and the second ring element (3) or between the first ring element (2) and the third ring element (4) by one coaxial with one

Bearing axis arranged cylinder jacket surface is formed.

10. Multi-row slewing bearing according to one of the preceding claims, characterized in that the first ring element (2) forms an axial guide in each case an axial direction for the second and the third ring element (3, 4).

11. Multi-row slewing bearing according to one of the preceding claims, characterized in that a radially extending contact surface (5a, 5b) between the first ring element (2) and the second ring element (3) or between the first ring element (2) and the third ring element (4) by one perpendicular to one

Bearing axis arranged annular surface is formed.

12. Multi-row slewing bearing according to one of the preceding claims, characterized in that the first ring element (2) has a substantially T-shaped cross-sectional profile and the second and the third ring element (3, 4) has a substantially triangular cross-sectional profile.

13. Multi-row slewing bearing according to one of the preceding claims, characterized in that the slewing bearing is designed as a double-row tapered roller bearing (1).

14. Multi-row slewing bearing according to one of the preceding claims, characterized in that the at least two bearing rows can absorb axial forces, radial forces and tilting moments.

15. Multi-row large-diameter rolling bearing according to one of the preceding claims, characterized in that the large rolling bearing as Ro tor torlagerung a wind turbine or as the main storage of a

Tunneling machine is used.