WO2018024831A1 - Axial plain bearing having wedge-shaped and stepped sliding surfaces - Google Patents

Abstract

The invention relates to an axial plain bearing having firmly integrated wedge surfaces (6) and latching surfaces (8) respectively adjoining them in a first sliding direction (12), wherein the wedge surfaces (6) are oriented such that a lubrication gap (3) is narrowed in the first sliding direction (12). On the ends of the latching surfaces (8) opposite the wedge surfaces (6) the axial plain bearing has in each case a step gap (16), which in a second sliding direction (12') opposite the first sliding direction (12) is designed such that the lubrication gap (3) is narrowed.

Description

 AXIAL SLIDING BEARINGS WITH WEDGE AND STUDS

 FACES

The hydrodynamic load carrying capacity of plain bearings is fundamentally ^¬ additionally dependent on a convergent, ie narrowing lubricating gap is present, see for example Wittelshofen et al. , Roloff / Matek Maschinenelemente, 20th Edition, Vieweg + Teubner Verlag Wiesbaden 2011, ISBN 978-3-8348-1454-8, chapter

15.1.5.

When the radial slide bearing, for example in the form of a circular cylindrical bearing, raises the convergent lubricating gap by the Ver ^¬ bearing of the shaft due to a radial force in the bearing cup independently a. By contrast, in the case of axial sliding bearings, a wedge surface is produced in the sliding surface by mechanical machining. In a sliding direction vi of the axial sliding bearing, the wedge surface follows the so-called Rastflä ^¬ che. The hydrodynamic pressure distribution then extends over both partial surfaces, the wedge surface and the detent surface. Axial ^¬ sliding bearing with wedge and the locking surfaces are described for example in WO2011 / 154078A1 (Daimler AG) 15.12.2011, DE102010044098 (Robert Bosch GmbH) 24.05.2012 and DE102014222514A1 (Bosch Mahle Turbo Systems GmbH & Co. KG) 14.01.2016.

However, if the sliding direction of the axial sliding bearing reverses, a wedge surface in the axial sliding bearing must likewise be provided for this opposite sliding direction v2. However, since ^¬ by itself reduces the hydrodynamic load carrying capacity for each sliding direction of vi and v2, since the force acting on the first sliding vi than convergent lubricating gap wedge surface for the opposite sliding direction v2 represents a divergent lubricating gap and thus hydrodynamically is not viable. Compared to an axial sliding bearing with two opposite wedge surfaces for both sliding directions vi and v2 has a thrust bearing with a wedge surface for only one sliding direction vi with otherwise the same dimensions (inner / outer diameter) a much higher load capacity. A WKA gearbox in a wind turbine (= WKA) is operated only in one direction of sliding. In contrast, in a series test run, two WTG transmissions are braked back-to-back on a load test rig and operated or tested under nominal load in both directions. DE102012000836A1 (Robert Bosch GmbH) July 18, 2013 describes such a back-to-back transmission test bench from two similar Ge ^¬ drives to be tested. For the relatively short time, usually only a few

Hours serial test run so Axialgleitlager are required, which are suitable for both sliding directions vi and v2; However, for the usually regular use of gears in a wind turbine for years, only axial sliding bearings that can be used in one sliding direction vi are sufficient. However, there is a desire that the prototype components are identical to the Se ^¬ rienbauteilen. In addition, the installation of Axialgleitlagern with two opposing wedge surfaces, which are suitable for both sliding directions vi and v2, requires more space. However, this is a waste because the second sliding direction v2 is not needed during actual operation on the turbine. In addition Axial ^¬ plain bearings are equipped with two opposing wedge surfaces substantially more expensive than axial plain with just a wedge surface.

It is an object of the present invention to provide an improved thrust bearing.

This object is achieved by an axial sliding bearing with the features specified in claim 1.

The Axialgleitlager has firmly incorporated wedge surfaces. The wedge surfaces are eingear ^¬ in a first sliding surface, which is a second sliding surface, preferably a plane mating surface, spaced from it by a lubricating gap opposite. In a first sliding direction, locking surfaces adjoin the wedge surfaces in each case. The wedge surfaces are aligned so that in the first Sliding direction of the lubrication gap is narrowed. The Axialgleit ^¬ bearing has at the opposite ends of the wedge surfaces of the locking surfaces each have a step gap. The step gap is designed in a direction opposite to the first sliding direction of the second sliding direction, that the lubricating gap is narrowed.

The invention is based on the realization that it tung for a driven only over a relatively short operating time Gleitrich- v2 of an axial plain bearing is sufficient, a hydrody ^¬ namic carrying capacity of the thrust bearing in this sliding ^¬ direction v2 by a step gap to realize, for example by a radial Lubricating groove is designed as a step gap. This becomes possible because the second sliding direction v2 is not needed during the actual operation of the axial sliding bearing on the turbine. The advantage of a stepped gap with respect to a full wedge surface is that it requires less space and thus the wedge area required in a direction opposite the main direction of operation forming sliding vi of the axial sliding bearing for the unrestricted hydrodynamic Tragfä ^¬ ability only minimally reduced. Thus, the existing in conventional trained Axialgleitlagern for two opposite directions Gleitver ^¬ avoided by two wedge surfaces.

The serial test run of a WKA gearbox in a gearbox usually takes only a few hours. For this small "service life requirement", a step gap can be used for the second sliding direction v2 of the axial sliding bearing during the series trial run.

Advantageous embodiments and further developments of the invention are specified in the dependent claims. According to a preferred embodiment of the invention, the step gap in the second direction of sliding towards the lubrication gap has at least one rising step. An advantage of this embodiment is that the number of stages increases the hydro- dynamic load capacity of the step gap in the second sliding direction can be adjusted.

According to a preferred embodiment of the invention, the step gap is arranged in a space of a radial lubrication groove of the axial sliding bearing. As a result, the hyd ^¬ rodynamically viable surface for the main operating direction forming sliding direction vi of the axial sliding bearing is not reduced. Since the hydrodynamic load carrying capacity for the second Gleitrich- tung v2 only a maximum of 100 percent of the rated torque SUC gene must ^¬, the step length of the stepped gap can be as small ge ^¬ hold that these into the construction space of the radial

Lubrication fit. A further preferred embodiment of the invention is a gear, comprising a gear and an inventive Axialgleitlager, wherein the gear is mounted axially by means of Axialgleitla ^¬ gers. According to a preferred embodiment of the invention, the transmission is designed as a planetary gear and the gear as a planetary gear of the planetary gear ausgebil ^¬ det. A further preferred embodiment of the invention is a wind turbine, comprising a rotor which is coupled via a Ro ^¬ torwelle torque transmitting with a transmission which is connected to a generator. Here, the Ge ^¬ gearbox formed in accordance with one of the embodiments of the invention described above.

The above-described characteristics, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood from the following description, which proceeds with reference to the drawings. It shows schematically and not true to measure ^¬ rod 1 shows a section of a conventional axial sliding bearing for a sliding direction.

Figure 2 is a section of a conventional thrust bearing for two opposite directions of sliding.

Fig. 3 is a sectional view of an inventive Axialgleitla ^¬ gers; Fig. 4 embodiments of step columns; Fig. 5 is a view of an axial sliding bearing.

6 shows an embodiment of a transmission according to the invention designed as a planetary gearbox; and

Fig. 7 shows an embodiment of a wind turbine according to the invention in a sectional oblique view. Fig. 1 shows a section through a conventional hydrodyna ^¬ premix axial sliding bearing for a single sliding direction 12 comprises axial thrust bearing two sliding surfaces 2, 4 with a between the sliding surfaces 2, 4, forming the lubricating gap 3. A first sliding surface 2 with surface structures has wedge-shaped surfaces 6 and Locking surfaces 8, wherein a wedge surface 6 in the sliding direction 12 of the Axialgleitlagers immediately followed by a locking surface 8. A second sliding surface 4, the so-called counter surface is formed as a flat surface without surface ^¬ structures. A wedge surface 6 is set against the anti-tread surface 4 in such a way that in the sliding direction 12 a narrowing lubricating gap 3 results, whereas a detent surface 8 runs parallel to the mating surface 4.

Between a locking surface 8 and a DA in the sliding direction 12 up following wedge surface 6, a lubricating groove is arranged in each case 10 in which lubricant trans ^¬ can be ported to the lubrication gap. 3 In the case of the hydrodynamic axial sliding bearing, the first sliding surface 2 moves in the sliding direction 12 relative to the second sliding surface 4. In this way, a convergent lubricating gap 3 forms in the region of the wedge surface 6, the effect of which is the hydrodynamic bearing capacity of the axial sliding bearing. The hydrody ^¬ namic pressure zone extends over both partial surfaces, ie wedge surface 6 and locking surface 8. This is indicated in Fig. 1 by the pressure distribution curve 14. The height of the pressure distribution curve 14 above the sliding surface 2 indicates the height of the hydrodynamic pressure.

Fig. 2 shows a section through a conventional hydrodyna ^¬ premix axial sliding bearing for two opposite sliding directions 12, 12 ^λ. The axial slide bearing comprises two sliding surfaces 2, 4 with a between the sliding surfaces 2, 4, forming the lubricating gap 3. A first sliding surface 2 with surfaces ^¬ structure has wedge-shaped surfaces 6, 6 ^λ and latching surfaces 8, wherein a first wedge surface 6 in a first sliding direction 12 the Axialgleitlagers immediately a locking surface 8 and after the locking surface 8 immediately follows a second wedge surface 6. A second sliding surface 4, the so-called mating ^¬ surface is formed as a flat surface without surface structures. A first wedge surface 6 is set against the mating surface 4 so that in the first sliding direction 12, a narrowing lubricating gap 3 results, whereas a locking surface 8 extends parallel to the mating surface 4. A second wedge surface 6 is set against the mating surface 4 so that in the first sliding direction 12, a widening lubricating gap 3 results.

Conversely, in one of the first sliding direction 12 opposite second sliding direction 12 ^{λ forms} a second wedge surface 6 a narrowing lubricating gap 3, whereas a first wedge surface 6 a widening lubricating gap 3 he ^¬ gives. Between a second wedge surface 6 ^λ with a widening lubricating gap and a first wedge surface 6 following in the first sliding direction 12 with a narrowing lubricating gap, a lubricating groove 10 is arranged, wherein lubricant can be transported into the lubricating gap 3.

In the hydrodynamic axial sliding bearing, the first sliding surface 2 moves relative to the second sliding surface 4 in one of the two sliding directions 12, 12 ^λ . In a first sliding direction 12, a convergent lubricating gap 3 forms in the region of the first wedge surface 6, the effect of which is the hydrodynamic bearing capacity of the axial sliding bearing. The hydrodynamic pressure zone extends over both partial surfaces, ie, the first wedge surface 6 and the first wedge surface 6 8 in the first sliding direction 12 below catch surface This is shown in Fig. 2 angedeu ^¬ tet by the first pressure distribution curve 14. The height of the pressure distribution curve 14 above the sliding surface 2 indicates the height of the hydrodynamic pressure.

In a second, the first sliding direction 12 opposite sliding direction 12 ^λ forms in the region of the second wedge surface 6 ^λ a convergent lubricating gap 3, the effect of which is the hydrodynamic load capacity of Axialgleitla- gers. The hydrodynamic pressure zone extends over both partial surfaces, ie, the second wedge surface 6 ^λ and the second wedge surface 6 ^λ in the second sliding direction 12 ^λ subsequent locking surface 8. This is indicated in Fig. 2 by the second pressure distribution curve 14 ^λ .

Fig. 3 shows a section of an axial sliding bearing according to the invention. The axial sliding bearing can be used for two opposite directions of sliding 12, 12 ^λ . The axial sliding bearing according to the invention is of the basic structure similar to the axial sliding bearing shown in Fig. 2 for two opposite

Sliding directions 12, 12 with the difference that the second wedge surface 6 ^λ of Axialgleitlagers shown in FIG. 2 in the axial sliding bearing according to the invention by a step gap 16th is replaced by: a first wedge surface 6 in a first slide ^¬ direction 12 of the axial sliding bearing according to the invention follows immediately a latching surface 8 and after the detent surface 8 UNMIT ^¬ telbar the step slit 16. A second sliding surface 4, the so-called counter surface is as a flat surface formed without surface structures.

The wedge surface 6 is against the mating surface 4 is so ^¬ is that results in the first sliding direction 12, a narrowing lubricating gap 3, whereas the locking surface 8 extends parallel to the mating surface 4. The step gap 16 is formed against the mating surface 4 so that in the first sliding direction 12, a step-widening lubricating gap 3 results.

Conversely, in one of the first sliding direction 12 opposite second sliding direction 12 ^{λ of} the step gap 16 forms a step-narrowing lubricating gap 3, whereas the wedge surface 6 is a widening lubricating gap 3 is.

Between a step slit 16 and a subsequent, in the first sliding direction 12 first wedge surface 6 with a tapered lubrication gap each have a lubrication groove 10 is arranged, wherein the lubricant trans ^¬ can be ported to the lubrication gap. 3

In the hydrodynamic axial sliding bearing, the first sliding surface 2 moves relative to the second sliding surface 4 in one of the two sliding directions 12, 12 ^λ . In a first sliding direction 12, a convergent lubricating gap 3 forms in the region of the first wedge surface 6, the effect of which is the hydrodynamic bearing capacity of the axial sliding bearing. The hydrodynamic pressure zone extends over both part surfaces, ie the wedge surface 6 and the wedge surface 6 in the first slide ^¬ direction 12 below catch surface 8. This is indicated in Fig. 3 by the first pressure distribution curve 14. there indicates the height of the pressure distribution curve 14 on the Gleitflä ^¬ che 2, the height of the hydrodynamic pressure.

In a second sliding direction 12 ^λ opposite the first sliding direction 12, a convergent lubricating gap 3 is formed in the region of the step gap 16, the effect of which is the hydrodynamic bearing capacity of the axial sliding bearing. The hydrodynamic pressure zone extends over both Teilflä ^¬ Chen, that is, the step gap 16 and the stepped slot 16 ^λ in the second sliding direction 12 below catch surface 8. This is interpreted in Fig. 3 ^λ by the second pressure distribution curve 14 at ^¬. The second pressure distribution curve 14 ^λ shows that the hydrodynamic pressure formed by the step gap 16 is less than the hydrodynamic pressure formed by the wedge surface 6. However, if the second sliding direction 12 ^λ is only used for a time-limited series test run, the replacement of a full-value wedge surface 6 by a step gap is justified and completely acceptable. Fig. 4 shows three different embodiments b), c) and d) for the dimensioning of a Stufenspalt- axial ^¬ sliding bearing in comparison to a wedge-surface thrust bearing a). In this case, the figure above shows a section of the Axi ^¬ algleitlagers with the sliding surfaces 2, 4, a between the sliding surfaces 2, 4 arranged lubricating gap 3 and an applied over the upper sliding surface 4 pressure distribution curve 14. The figure below shows a plan view of the lower sliding surface 2. The values of the pressure distribution curve 14 are plotted on the y-axis in the unit of the dimensionless load capacity index o, where o = phi ² / (nUB). In addition, the values of a second dimensionless load index Δ are plotted against the upper sliding surface 4, which in the form of a

Rectangles has a constant value over the entire length of the thrust bearing, where Δ = <p> hi ² / (nUB). For the formulas of the ratios o and Δ the following applies: p surface pressure or hydrodynamic pressure gradient, hi lubrication gap height,

η dynamic viscosity,

 U peripheral speed,

 B width of the warehouse,

 <p> average, specific pressure, and

L length of the segment.

The following applies: <p> = axial force F / (L B), ie per segment.

The wedge surface thrust bearing a) has a wedge surface of width B and length L, wherein the height of the lubricating gap at the wide location of the wedge is 2.25 hl. The Viable ^¬ ness Δ is 0.07.

The stepped gap axial sliding bearing b) has an upper plane of width B and length 0.45 L and a lower plane of the

Width B and length 0.55 L, which are separated by a step vonei ^¬ each other. In this case, the lubrication gap between the lower level of the first sliding surface 2 and the Gegenlaufflä ^¬ che 4 has a height of 1.7 hl. The carrying capacity is Δ

0.0725.

The Stufenspalt- axial plain bearing c) has a C-shaped obe ^¬ re level of width B and length 0.4 L and a lower level of width B and length 0.6 L, which are separated by a C-shaped step. In this case, the lubricating gap between the lower level of the first sliding surface 2 and the mating surface 4 has a height of 2 hl. The carrying capacity Δ be ^¬ contributes 0.114. The Stufenspalt- axial plain bearing d) has a C-shaped obe ^¬ re level of width B and length 0.76 L and a lower Ebe ^¬ ne the width of 0.76 B and 0.76 L length, which by a C-shaped Stage are separated from each other. It has the Lubrication gap between the lower level of the first sliding surface 2 and the mating surface 4 a height of 2.3 hl. The carrying capacity Δ is 0,123. The two dimensionless load capacity indices o and Δ show that at approximately the same hi the sustainable average pressure <p> at the step gap is always greater than in the case of the pure wedge gap. With an optimized step gap design as in d), a load-bearing capacity of Δ = 0.123 results in comparison to the wedge gap on Δ = 0.07.

Fig. 5 is a view of a thrust bearing again, the ^¬ sen section III-III in Fig. 3 is shown. On a Wel ^¬ le 18, a second ring 40 is rotatably disposed, which carries a plane mating surface 4. The mating surface 4 is spaced a lubricating gap 3 of a first ring 20, which bears a sliding surface 2 of Fig. 3, ie with wedge ^¬ surface 6, catch surface 8 and step slit 16. The first ring 20 relative to the shaft 18 arranged dormant, which pierces the first ring 20 without contact in a central ring opening of the first ring 20. By Rotati ^¬ on the rotating shaft 18 with the second ring 40 with the mating surface relative to the first ring 20 to the thrust bearing surface structure 6, 8, 16, a hydrodynamic bearing thrust bearing is formed.

Fig. 6 shows an embodiment of a transmission according to the invention, which is designed as a planetary gear. The transmission 50 includes a provided with a helical gear 34 planetary wheel 55, which by means of a sliding bearing ^¬ sleeve 33 on a fixed in a support flange 32 of a Planetenträ ^¬ gers pinion shaft 30 about a rotation axis 35 which sammenfällt supply with a symmetry axis of the pinion shaft 30 rotatably is stored. The planet gear meshes simultaneously with a ring gear, not shown, and a sun gear, not shown. In an annular region of the front end which directly surrounds the planetary gear axle 30 surface of the planet 55, a second ring 40 is fixed against rotation, the sliding surface is separated from an opposite sliding surface of a first ring 20 through a lubrication gap. The first ring 20 is coaxially fixed to the second ring 40 on the support cheek 32 of the planet carrier by screwings 31 rotatably. The planet 55 of the planetary gear ^¬ 50 is axially supported by means of the axial sliding bearing formed by the two rings 20, 40. Fig. 7 shows an embodiment of an inventive

Wind turbine 70 in a sectional oblique view. The wind turbine 70 includes a rotor 75 which is connected via a rotor shaft 54 to transmit torque with a Planetengetrie ^¬ be 50. The rotor shaft 54 is received in a rotor bearing 58. The planetary gear 50 in turn is coupled to a generator 76 for generating electricity. The rotor bearing 58, the rotor shaft 54, the planetary gear 50 and the generator 76 belong to a drive train 60 of the wind turbine 70. In the planetary gear 50 at least one not shown planet carrier 52 is included, which includes an embodiment of the invention Axialgleitlagers. In the axial sliding bearing according to the invention, at least one planetary gear 55 of the planetary gear is axially ge ^¬ superimposed. As a result, the planetary gear 50 can be operated in two directions of rotation.

Claims

claims 1. Axial sliding bearing with firmly incorporated wedge surfaces (6) and in a first sliding direction (12) each subsequent thereto locking surfaces (8), wherein the wedge surfaces (6) are aligned so that in the first sliding direction (12) a lubricating gap (3 ) is narrowed, characterized in that the Axialgleitlager at the wedge surfaces (6) opposite ends of the locking surfaces (8) each have a step gap (16) which in one of the first sliding direction (12) opposite second sliding direction (12 ^λ ) is formed so that the Grease gap (3) is narrowed. 2. Axialgleitlager according to claim 1, wherein the step gap (16) in the second sliding direction (12 ^λ ) to the lubrication gap (3) towards at least one rising step. 3. Axialgleitlager according to claim 1 or 2, wherein the Stu fenspalt (16) in a space of a radial lubrication groove (10) of the Axialgleitlagers is arranged. 4. gear (50) comprising a gear (55) and an axial ^¬ slide bearing according to one of the preceding claims, characterized in that the gear (55) is axially supported by means of the Axialgleitlagers. 5. Transmission (50) according to claim 4, wherein the transmission (50) is designed as a planetary gear and the gear (55) is designed as a planetary gear of the planetary gear. Is connected 6. Wind power plant (70) comprising a rotor (75) via a rotor shaft (54) is a torque-transmitting coupled to a Ge ^¬ gear (50) comparable to a generator (76) characterized in that the transmission (50) is designed according to claim 4 or 5.