DE102007053526A1 - Storage of a planetary gear to optimize the load distribution - Google Patents

Abstract

The invention relates to an arrangement for mounting a planetary gear (1) of a planetary gear on a bearing pin (2), comprising at least three axially juxtaposed rows of bearings each with cylindrical and within a row of bearings equally long rolling elements (5, 10, 11), wherein the bearing rows in Comparing rolling elements (5, 10, 11) having at least two different Wälzkörperlängen. In order to increase the service life of the arrangement or to avoid oversizing, at least one of the two axially further outlying bearing rows has rolling bodies with smaller rolling body lengths.

Description

Field of the invention

The The invention relates to an arrangement for mounting a planetary gear a planetary gear on a bearing pin comprising at least three axially juxtaposed rows of bearings, each with cylindrical and rolling elements of the same length within a bearing row, wherein the bearing rows in comparison to each other rolling elements with at least two different Wälzkörperlängen exhibit. The rolling element length corresponds Here, the axial extent of the cylindrical rolling elements. Such an arrangement is in particular as a gearbox mounting Wind turbines suitable.

Background of the invention

In wind turbines, a planetary gear is usually used for speed conversion to the main shaft, which is driven by the rotor blades. A planetary gear is well known, for example http://de.wikipedia.org/wiki/Planetengetriebe , It consists of a ring gear with internal teeth, usually three planet wheels and a sun. In general, a fixed ring gear is used in wind turbines. The three planets driven by the main shaft travel in this and drive, because in engagement with the sun, the sun in the center.

The Planetary gear is typically on the bearing pin through several stored axially juxtaposed rows of warehouses, each having cylindrical rolling elements.

Out The prior art has the problem that the load distribution over these warehouses are not even. Under Load distribution here is the distribution of the bearing pin and planetary gear transmitted force to the individual rows of bearings to understand.

A not uniform load distribution leads to that the rolling elements of each bearing rows different forces between indoor and Must transfer outer ring. Ultimately leads this with the same dimensioning of the bearing rows to a reduction the life of the bearing assembly, as depending on the load distribution certain rows of storage are more heavily loaded and fail earlier. Around avoid early failure of the bearing assembly would have increased the load rating of all storage lines accordingly become. However, this leads to a costly oversizing of such Warehouse rows, which are only slightly smaller if the load distribution is unequal are charged. Oversizing is also particular due to the resulting larger axial Space to avoid the bearing assembly.

From the DE 10 2005 049 185 A1 a bearing of a planetary gear for a wind turbine with several axially adjacent rows of bearings is known, according to a first embodiment of the raceway diameter of a remote from the axial edge of the planet, ie axially inner, bore portion is smaller than the raceway diameter of an adjacent of the axial edge of the planetary gear, ie axially outer, bore section. According to another embodiment of the DE 10 2005 049 185 A1 is the diameter of the cylindrical rollers of an axially inner cylindrical roller bearing is greater than the diameter of the cylindrical rollers of an axially outer cylindrical roller bearing.

From the EP 1 553 315 A1 is a bearing assembly consisting of three rows of bearings with cylindrical rolling elements and an associated planetary gear assembly for wind turbines known. In this case, longer rolling elements are to be used in the bearing rows, which are more heavily loaded due to their axial position within the bearing assembly and due to the load case. This leads to an increased load capacity of said bearing rows, whereby the life of the bearing assembly can be increased.

adversely in the known from the prior art construction with different Track diameter in individual rows of bearings is the high cost in the production of raceways. The result is higher ones Costs and longer design and processing times. Moreover, this solution already has to be timed out the design phase are incorporated, d. H. retrofitting existing ones Stock to improve load distribution is usually not possible.

About that In addition, for cylindrical rollers with different diameter adjust the machine setting accordingly during production a more complex sorting in terms of roll diameter required. In any case, the assembly is also difficult, because the different roll diameter with the bare Eye can not be detected.

The method known from the prior art to use longer rolling elements in more heavily loaded rows of warehouses, has the disadvantage that this does not lead to a more uniform load distribution. In particular, less heavily loaded bearing rows still remain lightly loaded and thus only contribute a small part of the total load. This results in an unnecessary oversizing of the bearing assembly, especially in the axial Extension.

Object of the invention

Of the Invention is therefore based on the object in an aforementioned Arrangement to avoid the disadvantages of the prior art described.

Summary of the invention

The This object is achieved according to the invention by that at least one of the two axially further outward Bearing rows Rolling elements with smaller rolling element lengths having.

Thereby is achieved by the invention that in particular the load distribution on the individual rows of bearings in a simple and cost-effective manner can be optimized to a longer life to reach or to avoid oversizing.

While the operation of the bearing assembly turns over a certain load distribution the warehouse rows. This load distribution is specific to one Use case and depends on the case-specific load situation and the rolling element stiffness.

One Factor that also influences the load situation is the type of Gearing of the planetary gear, z. B. a helical toothing, because the corresponding engagement of the planet gear with the ring gear to a characteristic distribution of forces on the planetary gear leads. In general, however, during the duration of respective application case the load situation, d. H. the between Bearing pin and planetary gear to be transmitted force, constant.

The Stiffness of a body describes the relationship between the power that acts on it and its resulting elastic deformation. The greater the stiffness of a body, the lower it gets at one deform certain force. The rolling element stiffness hangs from the geometry of the rolling elements - at cylindrical rolling elements practically only from the Length - as well as the material of the rolling element from.

Around in a given application, a uniform To achieve load distribution, thus has the rolling element stiffness the rolling elements of certain rows of bearings varies become. A uniform load distribution means Here is a load distribution as z. B. in an axial view symmetrical load situation and bearing rows with rolling elements equal stiffness would occur in practice. The means, the always present in practice small fluctuations the load distribution is not taken into account.

This taking advantage of the invention achieves a uniform Load distribution through targeted modification of the rolling element stiffnesses in particular the fact that selectively used differently long rolling elements become. Compared to diameter changes, this has the advantage that the required differences in rolling element lengths usually of the order of some Millimeters. Cylindrical rolling elements are the same Diameter with different rolling element lengths in this order of magnitude are usually considered so-called standard lengths available, so that no additional production costs arise. on the other hand is the assembly without additional effort possible because the different Wälzkörperlängen with can be recognized by the naked eye.

Become while rolling elements with less Wälzkörpersteifigkeit used in the warehouse rows, due to the given load situation be subjected to the strongest, so these rolling elements of this Warehouse rows now stronger because of their lower stiffness compressed as the stiffer rolling elements of the rest Storage rows. This in turn causes the stiffer ones Rolling elements of the remaining rows of bearings stronger be charged. In this way, the Wälzkörpersteifigkeiten the rolling elements of all bearing rows be set so that a uniform Load distribution results.

The optimal distribution of the rolling element stiffnesses for a particular use case, through calculations, Simulations or experiments are set.

in this connection it turned out that at least one of the two axially further out lying rows of bearings in many applications stronger is loaded, as the remaining rows of storage. To be in this Initial case nevertheless a uniform load distribution to reach, according to the invention, therefore, this corresponding axially outer bearing row rolling elements with smaller Wälzkörperlängen on.

According to the invention thus the desired optimization of the load distribution over all warehouse rows in a simple and cost-effective manner be achieved. Thus, an oversizing of the bearing assembly be avoided and minimizes the axial extent of the arrangement become.

The solution according to the invention can be used in several single-row bearings and in one or more multi-row bearings. The advantage of using several single-row bearings is that standard bearings can be used, whereby a simple and inexpensive construction is possible. The advantage of multi-row bearings is their low axial installation space. Preferred embodiments see multi-row bearings with three, four or five rows of warehouses. It is also possible to provide a direct bearing on the planetary gear with or without inner ring to make the bearing assembly in the radial direction even more compact. In principle, either full complement or cage-guided storage rows can be used. It can be used within a bearing assembly both full complement as well as cage-guided storage rows.

According to one preferred embodiment, both axially further outward lying rows of rolling elements with smaller Wälzkörperlängen on. From practical Experiences, experiments and technical calculations were that each outermost in the axial direction Warehouses are stronger in many applications are loaded as the intervening in the axial direction Storage rows. This can result in misalignment in certain applications the shaft or at a helical toothing of the planetary gear resulting from the resulting force distribution.

According to one preferred embodiment is the distribution of Wälzkörperlängen on the rolling elements of the bearing rows in axial View symmetrical. In many applications arises a with respect to the axial center of the arrangement in axial direction symmetrical, albeit over all rows of bearings not uniform, load distribution. In these Cases can be symmetrical by an axial view arrangement the Wälzkörperlängen a uniform Load distribution can be achieved.

According to one preferred embodiment takes the rolling element length the rolling elements of those axially further outward lying bearing row whose rolling elements smaller Wälzkörperlängen has, to the other axially further outward bearing row steadily.

According to one preferred embodiment, the ratio from maximum to minimum rolling element length in the range of 1.1 to 3.0. The minimum rolling element length denotes the rolling element length of the rolling elements the bearing row whose value is the smallest. The maximal Rolling element length denotes the rolling element length the rolling elements of that bearing row whose value is greatest. At a value of this ratio below 1.1 is the optimization of the invention the load distribution not noticeable to wear. A value of this Ratio greater than 3.0 is in the Practice hardly necessary. According to a preferred Embodiment is the ratio of maximum to minimum rolling element length in the range from 1.3 to 2.0. For most applications, such Ratio optimizes the load distribution most effectively become.

According to one preferred embodiment, the rolling elements at least one bearing row profiling on. The profiling is within the at least one bearing row for all rolling elements equal. Under profiling is understood here that the generatrices of the cylindrical rolling elements, that is, on the lateral surface of the cylindrical rolling elements along its axis of rotation extending lines, not are straight. Due to the profiling, the surface pressure be better distributed over the career path, in particular with eccentric load of the rolling elements, so that achieves a longer life of the bearing assembly can be. According to preferred embodiments the profiling is cylindrical, circular or logarithmic. Such profiles are in Wälzkörperherstellung already known and describe in what form the withdrawal the diameter of the rolling elements in the axial direction the rolling elements in each case from the middle to the end faces the rolling element takes place. In a cylindrical ball Profiling has the rolling elements substantially a cylindrical shape, wherein at the transition between lateral surface and end faces corresponding radii are present. In a circular Profiling show the generatrices of the rolling elements a constant curvature. In a logarithmic Profiling follow the generatrices each from their center to the two front sides of a logarithmic profile. According to the invention it is possible that only one, several or all Bearings have profiled rolling elements. If several rows of bearings profiled rolling elements may have the same or a different profiling of Rolling elements of the bearing rows can be selected.

According to one preferred embodiment, the bearing assembly comprises both at least one cage-guided bearing row as well as at least one full complement bearing row. In this way The rigidity of the bearing assembly itself can be increased. Which of the rows of warehouses caged and which full can be executed while z. B. by experiments or simulations be determined. In particular, a combination is possible with different profiles of the rolling elements the series of orders.

According to a preferred embodiment, the planet gear has a helical toothing. According to the invention, it is advantageous that, in particular, the forces resulting from the helical gearing can be uniformly distributed from the tilting of the planetary gear relative to the ring gear via an optimally selected distribution of the rolling body stiffnesses onto the bearing rows. A helical toothing of the planetary gear usually leads to a higher load on the axially outer rows of bearings. In most applications, therefore, when using a helical gearing, the distribution of the rolling body lengths is to be carried out in such a way that both are located further outside bearing rows have rolling elements with smaller Wälzkörperlängen.

According to one preferred embodiment, the arrangement is in a Wind turbine used. The benefits of having a simple and cost-effective to achieve uniform Load distribution can be achieved, especially in large storage arrangements such as B. bearing arrangements for wind turbines important. An early failure of a bearing row would be due to the relatively poor accessibility and relatively high repair and downtime costs particularly disadvantageous. As well would be due to the size of the bearing assembly an oversizing of less heavily loaded warehouse rows because of the associated costs very disadvantageous.

Brief description of the drawings

embodiments The present invention will become apparent from the attached Characters. Hereby shows:

1 : an assembly consisting of a multi-row bearing with four rows of bearings,

2 : an assembly consisting of a multi-row bearing with three rows of bearings,

3 : an arrangement consisting of a multi-row bearing with three rows of bearings without inner ring,

4 : an arrangement consisting of a multi-row bearing with three rows of bearings comprising inner and outer ring and

5 : An arrangement consisting of two multi-row bearings, each with two rows of bearings.

Detailed description the drawing

1 shows an arrangement consisting of a multi-row warehouse with four rows of storage. Shown is a sectional view of the arrangement for mounting a planetary gear 1 on a corresponding bearing pin 2 , An inner ring 3 is provided, the shelves 4 for an axial guidance of the rolling elements 5 having. The embodiment shown has no outer ring, instead, the rolling elements run directly on the bore surface 6 of the planet wheel 1 from.

The rolling elements of the four rows of bearings have two different Wälzkörperlängen, I ₁ and I ₂ , whose distribution is symmetrical in axial view. In the present case, both in the axial direction of the bearing bolt outer rows of bearings on rolling elements with a smaller Wälzkörperlänge, ie I ₁ . <I ₂ . This can be z. B. from the use of helical gearing 7 The result of the planetary gear, in spite of the resulting force distribution to achieve a uniform load distribution over all rows of bearings.

2 shows an arrangement consisting of a multi-row bearing with three rows of bearings. The basic structure corresponds to that of 1 , so that it can be referenced. The distribution of Wälzkörperlängen aims as well as in 1 shown distribution to a use case in which the outermost in the axial direction Lagereihen are more heavily loaded. That is, for the Wälzkörperlängen applies I ₁ . <I ₂ .

3 shows an arrangement consisting of a multi-row bearing with three rows of bearings without inner ring. In this case, a distribution of Wälzkörperlängen was selected, which steadily increases from one of the two in the axial direction of the bearing pin outermost bearing row to the other in the axial direction of the bearing pin outermost bearing row. In particular, I ₁ applies. <I ₂ . <I ₃ . In addition, this arrangement has no inner ring, ie the rolling elements roll directly on the bearing pin 2 from. Such an arrangement has the advantage of a lower radial height. The disadvantage, however, is that with surface damage of the bearing pin 2 this must be completely replaced. The axial guidance of the rolling elements 5 done by cages, not shown.

4 shows an arrangement consisting of a multi-row bearing with three rows of bearings comprising inner and outer ring. Here, the rolling elements roll on the inner ring 4 and the outer ring 12 from. This arrangement is not symmetrical in the axial view, yet both further outlying bearing rows have rolling elements with smaller Wälzkörperlängen. In the concrete arrangement, I ₂ applies. > I ₁ . > I ₃ . Such an arrangement is conceivable for cases in which the outermost rows of bearings, although stronger, are not equally heavily loaded in comparison with each other.

5 , shows an arrangement consisting of two multi-row bearings, each with two rows of bearings. The left bearing with inner ring 8th has two rows of bearings whose rolling elements 10 have lower rolling element lengths than the rolling elements 11 the two rows of bearings of the right bearing with inner ring 9 (I _1. <I ₂ ). It is advantageous here that bearing rows with rolling elements of different rolling body lengths are used in the bearing arrangement without the need for special inner rings have to be made. Rather, two conventional, multi-row bearings can be used. But it is also possible that the two bearings each have rows of bearings with rolling elements of different Wälzkörperlänge.

1

planet

2

bearing bolt

3

inner ring

4

shelf

5

rolling elements

6

bore surface

7

helical teeth

8th

inner ring

9

inner ring

10

rolling elements

11

rolling elements

12

outer ring

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102005049185 A1 [0006, 0006]
• EP 1553315 A1 [0007]

Cited non-patent literature

• - http://en.wikipedia.org/wiki/Planet_transmission [0002]

Claims (11)

Arrangement for mounting a planetary gear ( 1 ) of a planetary gear on a bearing pin ( 2 ), comprising at least three axially juxtaposed rows of bearings each with cylindrical and within a bearing row of equally long rolling elements ( 5 . 10 . 11 ), wherein the bearing rows compared rolling elements ( 5 . 10 . 11 ) having at least two different Wälzkörperlängen, characterized in that at least one of the two axially further outlying bearing rows has rolling elements with smaller Wälzkörperlängen. Arrangement according to claim 1, characterized characterized in that both axially further outboard Bearing rows Rolling elements with smaller rolling element lengths exhibit. Arrangement according to claim 2, characterized characterized in that the distribution of Wälzkörperlängen on the rolling elements of the rows of bearings in axial view is symmetrical. Arrangement according to claim 1, characterized characterized in that the rolling element length the rolling elements of those axially further outward lying bearing row whose rolling elements smaller Wälzkörperlängen has, to the other axially further outboard bearing row steadily increases. Arrangement according to one of the claims 1-4, characterized in that the ratio from maximum to minimum rolling element length in the range of 1.1 to 3.0. Arrangement according to claim 5, characterized characterized in that the ratio of maximum to minimum Rolling element length in the range of 1.3 to 2.0 lies. Arrangement according to one of claims 1-6, characterized in that the rolling bodies ( 5 . 10 . 11 ) have at least one bearing row profiling. Arrangement according to claim 7, characterized characterized in that the profiling cylindrical-cylindrical, circular or logarithmic. Arrangement according to one of the claims 1-8, characterized in that the bearing assembly both at least one cage-guided bearing row as well includes at least one full complement bearing row. Arrangement according to one of claims 1-9, characterized in that the planetary gear ( 1 ) a helical gearing ( 7 ) having. Arrangement according to one of claims 1-10, characterized in that the arrangement in a wind turbine is used.