Mounting of a spur gear on a planet carrier
The drive arrangement supports the spur gear on the planet carrier's hub with a recess and a fixed connection to the sun gear, addressing space and speed issues, thereby improving bearing life and durability in wind turbine components.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ZF FRIEDRICHSHAFEN AG
- Filing Date
- 2025-12-15
- Publication Date
- 2026-07-23
AI Technical Summary
Existing drive arrangements in wind turbines require significant installation space and suffer from speed differences between components, leading to reduced bearing life and increased maintenance needs.
A drive arrangement where the spur gear is partially or fully supported on a hub of the planet carrier, with a recess in the spur gear and a rotationally fixed connection to the sun gear, utilizing bearings within the recess and a coupling element to minimize space and reduce speed differences.
This design reduces installation space and minimizes speed differences, enhancing bearing life and overall durability by optimizing the distribution of loads and reducing the need for additional support components.
Smart Images

Figure EP2025087053_23072026_PF_FP_ABST
Abstract
Description
[0001] ZF Friedrichshafen AG File 302296 Friedrichshafen 2024-12-16
[0002] Bearing of a spur gear on a planetary carrier
[0003] The invention relates to a drive arrangement according to the preamble of claim 1.
[0004] The invention is based on the objective of making available a drive arrangement for a wind turbine that is improved compared to the prior art.
[0005] This problem is solved by a drive arrangement according to claim 1. Preferred embodiments are included in the dependent claims and result from the following description and the exemplary embodiments shown in the figures.
[0006] The drive arrangement according to the invention comprises a planet carrier and a spur gear. The planet carrier is rotatably mounted, for example in a housing or in a housing-fixed structure.
[0007] The spur gear is arranged coaxially with the planet carrier. This means that one axis of rotation of the planet carrier and one axis of rotation and / or central axis of the spur gear coincide.
[0008] The planet carrier has a hub. This hub is connected to the rest of the planet carrier in one or more parts. The term "hub" refers to a part of the planet carrier that is cylindrical or hollow cylindrical in shape, or that consists of several cylindrical or hollow cylindrical sections.
[0009] According to the invention, the spur gear is at least partially supported on the hub. This means that at least one bearing arrangement supporting the spur gear is mounted on the hub. A bearing arrangement is defined as an arrangement consisting of one or more bearings. Preferably, the gear is supported exclusively on the hub. In this case, all bearing arrangements supporting the spur gear are mounted on the hub. The described mounting of the spur gear is advantageous because it reduces the required installation space in the axial direction. ZF Friedrichshafen AG File 302296 Friedrichshafen 2024-12-16
[0010] Preferably, the spur gear is further developed with a recess. This recess is preferably arranged axially centrally in the spur gear. This means that a central axis of the recess coincides with the axis of rotation of the planet carrier and the spur gear. In particular, a central axis of the hub can coincide with the central axis of the recess.
[0011] According to the further development, the hub engages in the recess of the spur gear. At least part of the hub is therefore located within the recess. This at least part of the hub can be an axial end piece or a central piece. This further development simplifies the mounting of the spur gear on the hub.
[0012] In a preferred embodiment, the bearing arrangement described above is at least partially, and preferably completely, located within the recess. This allows the use of commercially available bearings for the bearing arrangement. For example, two tapered roller or ball bearings arranged in an X or O configuration can be used as the bearing arrangement.
[0013] The planet carrier is preferably further developed as part of a planetary stage, which, in addition to the planet carrier, comprises a sun gear, a ring gear and one or more planet gears, each rotatably mounted in the planet carrier and meshing with the sun gear and / or the ring gear.
[0014] According to the further development, the sun gear is rotationally fixed to the spur gear. Thus, a rotationally fixed connection exists between the sun gear and the spur gear. This counteracts rotations of the sun gear and the spur gear relative to each other, so that the sun gear and the spur gear – apart from deviations resulting from deformations, which can be caused, for example, by load or temperature changes – always rotate or remain stationary at the same speed. This further development, in conjunction with the rotatable mounting of the spur gear on the hub of the planet carrier, results in a reduced speed difference within the bearing arrangement, with which the spur gear on the hub ZF Friedrichshafen AG File 302296 Friedrichshafen 2024-12-16
[0015] is stored. This is advantageous with regard to the service life of the bearing arrangement.
[0016] In a preferred embodiment, the rotationally fixed connection between the sun gear and the spur gear is achieved by a sun shaft, which is rotationally fixed to both the sun gear and the spur gear. According to this embodiment, the sun shaft passes through the hub and / or the spur gear. For this purpose, the hub and / or the spur gear can be hollow, i.e., with a continuous recess. In this case, the sun shaft passes through the respective recess. The sun shaft, as designed in this embodiment, simplifies the structural design of the rotationally fixed connection between the sun shaft and the spur gear.
[0017] In a preferred embodiment, the rotationally fixed connection between the sun shaft and the spur gear is established by a coupling element. This element extends essentially radially, that is, orthogonally to the aforementioned axis of rotation. It is rotationally fixed to the sun shaft and the spur gear.
[0018] The further development stipulates that the sun gear and the coupling element are arranged on opposite axial sides of the hub. This means that the hub extends axially between the sun gear and the coupling element. The coupling element further simplifies the design of the rotationally fixed connection between the sun gear shaft and the spur gear.
[0019] The coupling element is preferably further developed as an axial abutment for the aforementioned bearing arrangement. This eliminates the need for one abutment component.
[0020] In a preferred embodiment, the planet carrier is rotatably mounted in a housing or a housing-fixed support structure. A housing-fixed support structure is defined as a support structure that is fixed within the housing. In particular, the housing can form the support structure as a single piece. ZF Friedrichshafen AG File 302296 Friedrichshafen 2024-12-16
[0021] A bearing arrangement, in which the planet carrier is rotatably mounted in the housing or the housing-fixed support structure, is located axially between the sun gear and the bearing arrangement in which the spur gear is mounted on the hub. This is advantageous with regard to the distribution of the loads acting on the hub from the planetary stage and via the spur gear.
[0022] The housing-mounted support structure preferably extends substantially radially, with both the housing-mounted support structure and the bearing arrangement, by which the planet carrier is rotatably mounted in the housing-mounted support structure, being arranged axially between the sun gear and the first bearing arrangement. A web of the planet carrier can be arranged axially between the sun gear and the bearing arrangement, by which the planet carrier is rotatably mounted in the housing or the housing-mounted support structure. In particular, the aforementioned components can be arranged in the following axial sequence: sun gear, web of the planet carrier, bearing arrangement, by which the planet carrier is rotatably mounted in the housing or the housing-mounted support structure, bearing arrangement, by which the spur gear is mounted on the hub, and coupling element.
[0023] Preferably, the drive arrangement is further developed with a shaft and a pinion mounted on the shaft. In particular, the pinion can be connected to the shaft by friction and / or positive locking, or be formed integrally through the shaft. The pinion meshes with the spur gear.
[0024] The further development stipulates that the shaft is rotatably mounted in the aforementioned support structure. This results in a particularly compact design of the drive assembly.
[0025] Preferred embodiments of the invention are shown in the figures.
[0026] Matching reference numbers indicate identical or functionally equivalent characteristics. Specifically, this shows:
[0027] Fig. 1 shows a sectional view of a drive assembly; ZF Friedrichshafen AG File 302296 Friedrichshafen 2024-12-16
[0028] Fig. 2 shows a first bearing configuration; and
[0029] Fig. 3 shows a second bearing configuration.
[0030] The drive arrangement 101 shown in Fig. 1 comprises a planetary gear stage 103 and a spur gear stage 105. The planetary gear stage 103 includes a ring gear 107, several planet gears 109, a planet carrier 111, and a sun gear 113. The planet gears 109 mesh with the ring gear 107 and the sun gear 113, respectively. They are rotatably mounted in the planet carrier 111.
[0031] The spur gear stage 105 includes a spur gear 115 and an output shaft 117. The output shaft 117 forms a pinion 119 in one piece, which meshes with the spur gear 115.
[0032] The planet carrier 111 has an output-side web 121. Planet bolts are fixed in the web 121, on which the planet gears 109 are rotatably mounted. In addition to the output-side web 121, the planet carrier 111 can have a second, input-side web. In this case, the planet gears 109 are arranged axially between the input-side and the output-side web 121.
[0033] A hub 123 is integrally formed on the output side of the gear web 121. This hub extends from the web 121 towards the spur gear stage 105. An axial end piece of the hub 123 engages in a continuous, axially centrally located recess of the spur gear 115. The spur gear 115 is rotatably mounted on the hub 123 by means of a first bearing arrangement 125, which in the illustrated embodiment consists of two tapered roller bearings arranged in an X configuration.
[0034] A sun gear shaft 127, integrally connected to the sun gear 113, runs through the hub 123 and the aforementioned recess in the spur gear 115. The sun gear 113 is arranged at a first axial end of the sun gear shaft 127. ZF Friedrichshafen AG File 302296 Friedrichshafen 2024-12-16
[0035] A substantially disc-shaped coupling element 129 extends between a second axial end of the sun shaft 127, opposite the first axial end, and the spur gear 115. The coupling element 129 establishes a rotationally fixed connection between the sun shaft 127 and the spur gear 115. Specifically, the sun shaft 127 is rotationally fixed to the coupling element 129 via a splined connection. The coupling element 129, in turn, is screwed to the spur gear 115.
[0036] A housing section 131 extends in a substantially radial direction between the planetary gear stage 113 and the spur gear stage 105. The housing section 131 serves as a support structure for the planet carrier 111 and the hub 123. The hub 123 is supported in the housing section 131 by means of a second bearing arrangement 133, which in the illustrated embodiment is designed as a double tapered roller bearing in an X-configuration. The output shaft 117 is supported on the input side by a bearing 135 in the housing section 131.
[0037] In the embodiment shown in Fig. 1, the planet carrier 111 is supported exclusively by the second bearing arrangement 127. Apart from the bearings belonging to the second bearing arrangement 127, there are no other bearings supporting the planet carrier 111. In particular, starting from the gears 107, 109, 113 on the side opposite the bearing arrangement 133, there are no further bearings for the planet carrier 111.
[0038] In the bearing configuration shown in Fig. 2, the bearings of the first bearing arrangement 125 are arranged in an O-configuration. Apart from this, the above statements regarding the embodiment shown in Fig. 1 apply mutatis mutandis to Fig. 2.
[0039] In the bearing configuration shown in Fig. 3, the first bearing arrangement 133 consists of a single single-row tapered roller bearing. A further tapered roller bearing 301, with which the planet carrier 111 is rotatably mounted in the housing, is located on the input side. The two tapered roller bearings can be arranged in an O-configuration or, as shown in Fig. 3, in an X-configuration. Likewise, the bearings can be arranged in a different configuration. ZF Friedrichshafen AG File 302296 Friedrichshafen 2024-12-16
[0040] The first bearing arrangement 125 may be arranged in an O-configuration or, as shown in Fig. 3, in an X-configuration. ZF Friedrichshafen AG File 302296
[0041] Friedrichshafen 2024-12-16
[0042] Reference sign
[0043] 101 Drive arrangement
[0044] 103 Planetary Stage
[0045] 105 Spur gear stage
[0046] 107 Ring gear
[0047] 109 Planetary gear
[0048] 111 Planetary Carriers
[0049] 113 Sun wheel
[0050] 115 Spur gear
[0051] 117 Output wave
[0052] 119 sprockets
[0053] 121 Cheek
[0054] 123 hub
[0055] 125 Storage arrangement
[0056] 127 Sun wave
[0057] 129 Coupling element
[0058] 131 Housing section
[0059] 133 Storage arrangement
[0060] 301 Tapered roller bearings
Claims
ZF Friedrichshafen AG File 302296 Friedrichshafen 2024-12-16 Patent claims 1. Drive arrangement (101) for a wind turbine, comprising a rotatably mounted planet carrier (111) and a spur gear (115) arranged coaxially to the planet carrier (111); characterized in that the spur gear (115) is rotatably mounted at least partially on a hub (123) of the planet carrier (111).
2. Drive arrangement (101) according to claim 1; characterized in that the spur gear (115) has a recess into which the hub (123) engages.
3. Drive arrangement (101) according to the preceding claim; characterized in that a first bearing arrangement (125) with which the spur gear (115) is mounted on the hub (123) is arranged at least partially within the recess.
4. Drive arrangement (101) according to one of the preceding claims; characterized by a planetary stage (103) comprising the planetary carrier (111) and a sun wheel (113); wherein the sun gear (113) is connected to the spur gear (115) in a rotationally fixed manner.
5. Drive arrangement (101) according to the preceding claim; characterized by a sun shaft (127) which is rotationally fixed to the sun gear (113) and the spur gear (115), and which passes through the hub (123) and / or the spur gear (115).
6. Drive arrangement (101) according to the preceding claim; characterized by a coupling element (129) extending substantially radially, which is rotationally fixed to the sun shaft (127) and the spur gear (115); wherein The sun gear (113) and the coupling element (129) are arranged on different axial sides of the hub (123). ZF Friedrichshafen AG File 302296 Friedrichshafen 2024-12-16 7. Drive arrangement (101) according to the preceding claim, with reference to claim 3; characterized in that the coupling element (129) forms an axial abutment for the first bearing arrangement (125).
8. Drive arrangement (101) according to one of the preceding claims; characterized by a second bearing arrangement (133) with which the planet carrier (111) is rotatably mounted in a housing or a housing-fixed support structure (131); wherein the second bearing arrangement (133) is arranged axially between the sun gear (113) and the first bearing arrangement (125).
9. Drive arrangement (101) according to the preceding claim; characterized by a shaft (117) with a pinion (119) mounted on the shaft (117) which meshes with the spur gear (115); wherein the shaft (117) is rotatably mounted in the support structure (131).