Arrangement for supporting a spur gear

Abstract

The invention relates to an arrangement comprising a shaft (115), a spur gear (101), a first housing-fixed support structure (119), a second housing-fixed support structure (123), a first bearing (117) and a second bearing (119), wherein: the spur gear (101) has a web (107) which is arranged between the first bearing (117) and the second bearing (119) and which connects a gear rim (105) and a hub (11) of the spur gear (101) to one another; the shaft (115) is connected to the hub (111) for conjoint rotation. The gear rim (105) forms an outer running surface of the first bearing (117) or a seat for an outer ring of the first bearing (117) and an outer running surface of the second bearing (121) or a seat for an outer ring of the second bearing (121), wherein: the first support structure (119) forms an inner running surface of the first bearing (117) or a seat for an inner ring of the first bearing (117); and the second support structure (119) forms an inner running surface of the second bearing (121) or a seat for an inner ring of the second bearing (121).

Description

[0001] Arrangement for the bearing of a spur gear

[0002] The invention relates to an arrangement according to the preamble of claim 1.

[0003] From EP 3 464 894 B1, a wind turbine gearbox with a spur gear stage is known. The spur gear stage has a spur gear whose web is arranged eccentrically. This creates space inside the spur gear for a bearing arrangement.

[0004] An eccentric web leads to an eccentric distribution of forces. This is disadvantageous in highly loaded gearboxes, especially wind turbine gearboxes.

[0005] Therefore, spur gears with a central web are commonly used in wind turbine gearboxes. A corresponding spur gear is shown, for example, in EP 2 302 257 A2. The web connects a toothed ring of the spur gear to a shaft. Bearings are arranged on both sides of the web on the shaft, allowing the shaft and the spur gear to rotate within a gearbox housing.

[0006] The shaft is subjected to bending moments, which are absorbed via the bearings with a long lever arm. Therefore, the shaft must be made of high-strength steel, which is correspondingly expensive. The spur gear itself is forged. This is a disadvantage in terms of weight.

[0007] The invention is based on the objective of providing an arrangement that does not exhibit the disadvantages inherent in solutions known from the prior art. This objective is achieved by an arrangement according to claim 1. Preferred embodiments are included in the dependent claims and will become apparent from the following description and the exemplary embodiments illustrated in the figures.

[0008] The arrangement according to the invention comprises a shaft, a spur gear, a first housing-fixed support structure, a second housing-fixed support structure, a first bearing, and a second bearing. A housing-fixed support structure is a support structure that is fixed immovably within a gearbox housing relative to it. In particular, the gearbox housing itself can form such a support structure. The first housing-fixed support structure and the second housing-fixed support structure can be designed as separate parts or integrally connected. In particular, a gearbox housing can form the first housing-fixed support structure and / or the second housing-fixed support structure.

[0009] The spur gear has a web and a hub. The web is a structure that connects the gear's toothed ring to the hub. The web extends between the toothed ring and the hub. Preferably, the web extends axially. Preferably, the web joins the toothed ring and the hub integrally. In particular, the entire spur gear can be manufactured as a single piece.

[0010] The gear ring consists of teeth and a base body with teeth. The base body has the shape of a toroid that is rotationally symmetrical about an axis of rotation of the spur gear. In addition to the base body, the web and the hub are preferably also rotationally symmetrical with respect to the axis of rotation of the spur gear.

[0011] The bridge is preferably arranged partially or completely within the gear ring. Starting from the bridge or the part of the bridge arranged within the gear ring, the gear ring then extends radially outwards.

[0012] The hub is also arranged at least partially, preferably completely, within the gear ring.

[0013] The shaft is connected to the hub in a rotationally fixed manner. In particular, the shaft can be connected to the hub in a rotationally fixed manner by means of a splined connection. In this case, the shaft has external teeth and the hub has internal teeth. The external teeth and / or the internal teeth are preferably formed integrally by the shaft or the hub, respectively. The internal and external teeth are arranged coaxially with each other, that is, they have a common axis of rotation and / or central axis, and they engage positively with each other.

[0014] The gear is rotatably mounted in the first support structure by means of the first bearing and rotatably mounted in the second support structure by means of the second bearing. Specifically, the gear rim forms an outer raceway of the first bearing or a seat for an outer ring of the first bearing, and the gear rim forms an outer raceway of the second bearing or a seat for an outer ring of the second bearing. Similarly, the first support structure forms an inner raceway of the first bearing or a seat for an inner ring of the first bearing. The second support structure forms an inner raceway of the second bearing or a seat for an inner ring of the second bearing. In particular, the gear rim can integrally form the outer raceway of the first bearing and / or the outer raceway of the second bearing.Likewise, the first support structure can form the inner running surface of the first bearing and / or the second support structure can form the inner running surface of the second bearing in one piece. Preferably, however, the outer rings of the first bearing and / or the second bearing and the gear ring are designed as separate parts. Likewise, the inner ring of the first bearing and the first support structure are preferably designed as separate parts, and / or the inner ring of the second bearing and the second support structure are preferably designed as separate parts.

[0015] A seat for a ring of a bearing is a receptacle for the ring in which the ring can be fixed by force, form and / or material interlock, or in which the ring is fixed by force, form and / or material interlock.

[0016] The inner and outer raceways of a bearing are paired together. A pair of raceways forms a raceway pair, meaning raceways that slide directly against each other or via a lubrication gap, or that form tracks for the rolling elements located between them. An inner raceway differs from an outer raceway of the same raceway pair in that it is located radially further inwards, or closer to the bearing's axis of rotation. Conversely, the outer raceway of the raceway pair is located radially further outwards, or farther away from the axis of rotation. The surface normals of the outer raceway usually point towards the axis of rotation. Conversely, the surface normals of the inner raceway usually point away from the axis of rotation.

[0017] The outer ring of a bearing refers to the part of the bearing that forms the outer raceway of a pair of raceways. Similarly, the inner ring refers to the part of the bearing that forms the inner raceway of the pair of raceways.

[0018] Due to the bearing arrangement of the spur gear according to the invention, the inner running surfaces of the first and second bearings are fixed to the housing. The outer running surfaces are rotatably held with the spur gear. This results in a particularly compact and correspondingly space-saving design. The hub replaces a shaft used in conventional arrangements. This eliminates the shaft, thus saving the manufacturing costs.

[0019] In a preferred embodiment, at least one part of the first bearing is arranged radially between the first support structure and the gear ring. This at least one part of the first bearing is then located between two planes extending radially, i.e., orthogonally to an axis of rotation of the shaft and the spur gear, whose surface normals are parallel to the axis of rotation and which intersect the gear ring and the first support structure.

[0020] The further development provides that at least a portion of the second bearing is arranged radially between the second support structure and the gear ring. According to this further development, at least a portion of the second bearing is located between two further radially extending planes that intersect the gear ring and the second support structure. This further development saves installation space in the axial direction. In particular, the bearing arrangement of the spur gear occupies very little space in the axial direction. In a preferred embodiment, the described arrangement of at least a portion of the first bearing radially between the first support structure and the gear ring, and of at least a portion of the second bearing radially between the second support structure and the gear ring, is achieved by a first recess and a second recess in the spur gear, between which the web runs.In particular, these can be end-face recesses, that is, recesses that are milled into opposite end faces of the spur gear. Starting from the web, the end-face recesses are open in opposite axial directions.

[0021] The recesses each form a space for a bearing of the spur gear. Thus, the first recess forms a space for the first bearing; the second recess forms a space for the second bearing. Specifically, at least part of the first bearing is located in the first recess and at least part of the second bearing is located in the second recess.

[0022] In a preferred embodiment, the first support structure engages in the first recess. The second support structure engages in the second recess, according to the embodiment. Thus, according to the embodiment, at least a portion of the first support structure is located in the first recess; at least a portion of the second support structure is located in the second recess, according to the embodiment. The corresponding portions of the first and second support structures are suitable for forming a bearing seat for the first and second bearings, respectively. Viewed radially, according to the embodiment, the first support structure and the gear ring, as well as the second support structure and the gear ring, overlap.

[0023] The spur gear is preferably further developed such that the web is arranged centrally with respect to the gear ring. The gear ring then extends equally far radially from the web to both sides. In particular, the spur gear – except for the teeth – can be mirror-symmetrical about a plane extending radially, i.e., orthogonally to the aforementioned axis of rotation. Since the first support structure and the second support structure are fixed to the housing, the first support structure and / or the second support structure can be integrally connected to the housing. In a preferred embodiment, however, the first support structure and / or the second support structure are designed as separate pieces from the housing. Thus, according to this embodiment, the first support structure and / or the second support structure are not integrally connected to the housing. Parting surfaces then extend between the housing and the first support structure and / or between the housing and the second support structure.Such further training is advantageous with regard to the ease of assembly of the arrangement.

[0024] Preferably, the first support structure and / or the second support structure are detachably fixed in the housing. In particular, they can be screwed to the housing.

[0025] In a preferred embodiment, the second support structure is designed as a housing cover. A housing cover is a cover for a through-hole in the housing. This means that, in the assembled state, the second support structure at least partially covers the housing recess. Preferably, the second support structure is screwed to the housing along one opening of the recess. This embodiment allows the second support structure to be inserted into the housing through the recess for assembly.

[0026] The arrangement described above is preferably further developed as part of a wind turbine gearbox. Starting from the web, the first support structure is preferably arranged on the rotor side, i.e., in the direction of a wind-driven rotor of the wind turbine. Correspondingly, the second support structure is preferably arranged on the generator side with respect to the web, i.e., starting from the web and extending towards a generator of the wind turbine.

[0027] Preferably, the wind turbine gearbox is further developed with at least one planetary stage, an output shaft, and a pinion that is fixed to the output shaft in a rotationally fixed manner. In particular, the output shaft can form the pinion as a single unit. The pinion meshes with the spur gear. Thus, the teeth of the pinion and the teeth of the spur gear mesh with each other, allowing the pinion and the spur gear to rotate relative to each other at a fixed speed ratio. According to the further development, the shaft is also rotationally fixed to a sun gear of the planetary stage. In particular, the shaft can be integrally connected to the sun gear.

[0028] In a preferred embodiment, a planet carrier of the planetary stage is rotatably mounted by means of at least one bearing arrangement. In particular, the planet carrier can be mounted in the housing by means of the bearing arrangement. The first support structure is further developed as a fixing element for this bearing arrangement. This simplifies the design of the wind turbine gearbox, as the need for a separate fixing element is eliminated. Preferably, the fixing element forms an axial abutment for the bearing arrangement.

[0029] Preferred embodiments of the invention are illustrated in the figures. Matching reference numerals denote identical or functionally equivalent features. Specifically, the figures show:

[0030] Fig. 1 shows a spur gear stage;

[0031] Fig. 2 shows a first section; and

[0032] Fig. 3 shows a second detail.

[0033] The spur gear stage shown in Fig. 1 comprises a spur gear 101 and a pinion 103 arranged on an output shaft. The spur gear 101 and the pinion 103, or rather their teeth, mesh with each other.

[0034] The spur gear 101 has a toothed ring 105 and a web 107. The teeth of the spur gear 101 are formed on the outer circumference of the toothed ring 105. Extending from the inner circumference of the toothed ring 105, the web 107 extends radially inwards towards an axis of rotation 109 of the spur gear 101. The web 107 connects a hub 111, located internally and extending from the web towards the axis of rotation 109, to the toothed ring 105. The hub 111, in turn, forms an external toothing of a splined connection 113 within its interior. An internal toothing of the splined connection, which engages with the external toothing, is formed by a sun gear 115 of an upstream planetary gear stage.

[0035] The spur gear 101 is supported by a first bearing 117 in a first housing-fixed support structure 119 and by a second bearing 121 in a second housing-fixed support structure 123. The web 107 extends between the first bearing 117 and the second bearing 121.

[0036] The gear ring 105 forms bearing seats on its inner circumference for the first bearing 117 and the second bearing 121. A bearing seat for the first bearing 117 is located in a rotor-side recess in a rotor-side end face of the spur gear 101. Correspondingly, a bearing seat for the second bearing 121 is located in a recess on a generator-side end face of the spur gear 101.

[0037] The first support structure 119 and the second support structure 123 each form corresponding bearing seats. Specifically, the first support structure 119 forms a corresponding bearing seat for the first bearing 117. The second support structure 123 forms a corresponding bearing seat for the second bearing 121.

[0038] The first support structure 119 has a continuous recess in its axial center through which the sun shaft 115 passes. Accordingly, the splined toothing 113 and a sun gear formed by the sun shaft 115 are located on opposite axial sides of the first support structure 119.

[0039] The first support structure 119 is, as shown in Fig. 2, screwed to a housing 201. The housing 201 forms a bearing seat for a bearing assembly 203 of a planet carrier of a planetary stage, which also includes the aforementioned sun gear. Specifically, the housing 201 fixes the bearing assembly 203 in the radial direction and forms a shoulder as a rotor-side axial stop for the bearing assembly 203. The first support structure 119 serves as the generator-side axial stop for the bearing assembly 203.

[0040] The second support structure 123 is also screwed to the housing 201, as shown in Fig. 3. The screw connection is located outside the housing 201. Through an opening in the housing 201, the second support structure 123 engages the interior of the housing 201, where the components described above are located.

[0041] A pitch tube passes through the housing 201. This tube is supported in the second support structure 123 by means of a bearing 301. Accordingly, the second support structure 123 has a central recess through which the pitch tube passes and in which the bearing 301 is arranged.

[0042] Reference sign

[0043] Spur gear pinion ring gear bridge

[0044] pivot axis hub

[0045] Splined shaft bearing support structure bearing support structure housing bearing arrangement bearing

Claims

Patent claims 1. An arrangement comprising a shaft (115), a spur gear (101), a first housing-fixed support structure (119), a second housing-fixed support structure (123), a first bearing (117), and a second bearing (119); wherein the spur gear (101) has a web (107) arranged between the first bearing (117) and the second bearing (119), which connects a gear ring (105) and a hub (11) of the spur gear (101); and wherein the shaft (115) is rotationally fixed to the hub (111); characterized in that the gear ring (105) forms an outer running surface of the first bearing (117) or a seat for an outer ring of the first bearing (117) and an outer running surface of the second bearing (121) or a seat for an outer ring of the second bearing (121); wherein the first support structure (119) forms an inner running surface of the first bearing (117) or a seat for an inner ring of the first bearing (117);and wherein the second support structure (119) forms an inner running surface of the second bearing (121) or a seat for an inner ring of the second bearing (121).

2. Arrangement according to claim 1 ; characterized in that at least a part of the first bearing (117) is arranged radially between the first support structure (119) and the toothed ring (105) and at least a part of the second bearing (121) is arranged radially between the second support structure (123) and the toothed ring (105).

3. Arrangement according to the preceding claim; characterized in that the spur gear (101) has a first recess and a second recess, between which the web runs; wherein at least a part of the first bearing (117) is arranged in the first recess and at least a part of the second bearing (121) is arranged in the second recess.

4. Arrangement according to the preceding claim; characterized in that the first support structure (119) engages in the first recess and the second support structure (123) engages in the second recess.

5. Arrangement according to one of the preceding claims; characterized in that the bridge (107) is arranged centrally with respect to the toothed ring (105).

6. Arrangement according to one of the preceding claims; characterized by a housing (201); wherein the first support structure (119) and the housing (201) are designed as separate pieces, and / or the second support structure (123) and the housing (201) are designed as separate pieces.

7. Arrangement according to the preceding claim; characterized in that the second support structure (123) is designed as a housing cover.

8. Wind turbine gearbox; characterized by an arrangement according to one of the preceding claims.

9. Wind turbine gearbox according to the preceding claim; characterized by at least one planetary stage, an output shaft and a pinion (103) fixed non-rotatably on the output shaft; wherein the pinion (103) meshes with the spur gear (101); and wherein the shaft (115) is non-rotatably connected to a sun gear of the planetary stage.

10. Wind force transmission according to the preceding claim; characterized in that the first support structure (119) is designed as a fixing means for a bearing arrangement (203) of a planet carrier of the planetary stage.

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