Shaft connector

Abstract

An arrangement having a shaft (103), a hollow shaft (109) and a connector (107); the shaft (103) and the hollow shaft (109) being fixed by means of the connector (107) so as to preclude relative rotation between the shafts and extending in the same axial direction from the connector (107). The connector (107) forms a cavity which receives an axial end of the hollow shaft (109).

Description

[0001] Shaft connectors

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

[0003] Double-row rivet connections are commonly used to join a carbon shaft to a steel shaft. The rivets engage in paired recesses in the carbon shaft. The steel shaft and the carbon shaft are axially offset from each other and extend in different axial directions from the rivet connection.

[0004] Such connections are not suitable for joining nested shafts. If the shafts are nested, one row of rivets will be subjected to excessive stress, while the other row will experience comparatively little stress. This reduces the load-bearing capacity of the connection.

[0005] The invention is based on the objective of improving the connection between a shaft and a hollow shaft compared to 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 figures.

[0006] An arrangement according to the invention comprises a shaft, a hollow shaft, and a connector that fixes the shaft and the hollow shaft together in a rotationally fixed manner. In particular, rotationally fixed connections can exist between the connector and the shaft as well as between the connector and the hollow shaft. As a result, the shaft, the hollow shaft, and the connector rotate as a rotationally fixed unit about a common axis of rotation without twisting relative to each other.

[0007] Starting from the connector, the shaft and the hollow shaft extend in the same axial direction with respect to an axis of rotation and / or symmetry of the shaft, the hollow shaft, and / or the connector. The shaft and the hollow shaft are therefore located entirely on the same axial side of the connector. Specifically, the shaft and the hollow shaft lie entirely on a plane that runs radially, i.e., orthogonally to an axis of rotation and / or symmetry of the shaft, the hollow shaft, and / or the connector, and which intersects the connector. This results in a nested arrangement of the shaft and the hollow shaft. This means that the shaft is located at least partially inside the hollow shaft, or the hollow shaft is located at least partially inside the shaft. In the latter case, where the hollow shaft is located inside the shaft, the shaft itself is also designed as a hollow shaft.

[0008] According to the invention, the connector forms at least one cavity. This cavity accommodates an axial end of the hollow shaft. The cavity has an opening through which the axial end of the hollow shaft engages. Extending from the opening, the cavity preferably in the axial direction, follows the contour of the engaging axial end of the hollow shaft.

[0009] The cavity according to the invention enables a rotationally fixed fixation of the hollow shaft or the axial end of the hollow shaft engaging in the cavity within the connector. Such a connection can be designed to be very robust.

[0010] In a preferred embodiment, an axial end of the shaft is joined to the connector. According to this embodiment, a joining connection exists between the axial end of the shaft and the connector. In particular, this joining connection can be rotationally fixed, resulting in the aforementioned rotationally fixed connection between the shaft and the connector. Specifically, the shaft and the connector can be integrally joined.

[0011] In a preferred embodiment, the cavity and the axial end of the hollow shaft that engages with the cavity are identical in shape. This means that the cavity forms a negative mold of the axial end of the hollow shaft. If the axial end of the hollow shaft has the shape of a hollow cylinder, the cavity is also shaped as a hollow cylinder, according to the embodiment. The connector then forms the negative mold of a hollow cylinder. The cavity is preferably rotationally symmetrical. A corresponding axis of symmetry is identical to the central and / or rotational axis of the shaft, the hollow shaft, and / or the connector. In particular, the connector can be designed to be rotationally symmetrical. The opening of the cavity is preferably annular.

[0012] At least one part of the connector is U-shaped in longitudinal section, that is, in a sectional view that includes the axis of rotation and / or symmetry of the shaft, the hollow shaft, and / or the connector. This part of the connector consists of an inner hollow cylinder, an outer hollow cylinder, and a connecting piece. The inner hollow cylinder is located inside the outer hollow cylinder. The connecting piece extends between an axial end face of the inner hollow cylinder and an axial end face of the outer hollow cylinder. Both end faces are connected to each other via the connecting piece. In longitudinal section, the outer hollow cylinder and the inner hollow cylinder form two legs of the U. The connecting piece forms the base of the U in longitudinal section. The cavity that accommodates the axial end of the hollow shaft forms a punch of the U in longitudinal section.

[0013] In a preferred embodiment, the axial end of the hollow shaft is fixed in the connector's cavity with bolts. The connector has two recesses for each bolt. The bolts engage in two of these recesses. Between each of the two recesses is a recess in the hollow shaft, into which the respective bolt also engages. Thus, each bolt engages in two recesses of the connector and an intermediate recess in the hollow shaft. This embodiment of fixing the axial end of the hollow shaft in the connector's cavity with bolts results in a particularly strong connection.

[0014] Preferably, the two recesses of the connector into which a bolt engages are aligned and / or arranged coaxially with each other. Preferably, the recess of the hollow shaft located between the two recesses of the connector is also aligned with the recess located between them, and / or the recess located between them is arranged coaxially with the two recesses of the connector. The recesses of the hollow shaft are preferably through-holes. The bolts then extend through the respective recess of the hollow shaft and engage with their axial ends in two recesses of the connector. The recesses of the connector preferably open into the cavity of the connector.

[0015] In a preferred embodiment, at least some, and preferably all, of the bolts are arranged rotationally symmetrically with respect to the axis of rotation of the shaft, hollow shaft, and / or connector. The bolts, or the bolts belonging to the at least one part, can thus be mapped onto each other by rotating them by an angle less than 360° around said axis. This results in a circumferentially offset arrangement of the bolts, or the bolts belonging to the at least one part.

[0016] Since the bolts each engage in two recesses of the connector and an intermediate recess of the hollow shaft, the recesses are arranged in a rotationally symmetrical arrangement relative to each other, as further developed. The two recesses of the connector and the intermediate recess of the hollow shaft are therefore, as further developed, at least partially rotationally symmetrical about the axis of rotation and / or symmetry of the shaft, the hollow shaft, and / or the connector.

[0017] In a preferred embodiment, screws are provided to secure the bolts in the recesses. These screws fasten the bolts into the connector.

[0018] Each bolt has a hole to accommodate a screw. The screw is inserted through this hole and threaded into the connector. The bolt acts as a support for the screw, preferably for the screw head, at the opening of the hole. As the screws are inserted into the connector's thread, they are clamped between the bolt and the thread. This exerts a clamping force on the bolt, directed along the thread of the connector. This holds the bolts in position and prevents them from falling out.

[0019] In a preferred embodiment, the hollow shaft consists at least partially of a composite material, for example, a fiber-reinforced composite, preferably a fiber-reinforced composite such as carbon fiber composite. In particular, the axial end of the hollow shaft, which is received in the cavity of the connector, can be made of the composite material. Preferably, the entire hollow shaft consists of the composite material. This embodiment allows the advantages of a hollow shaft made of a composite material to be realized.

[0020] The hollow connector simultaneously avoids the usual disadvantages associated with connecting a steel shaft to a hollow shaft made of a composite material.

[0021] Preferably, the arrangement according to the invention, or one of the preferred embodiments described above, is further developed as part of a wind turbine gearbox with a generator hub. The shaft is designed as a solar shaft.

[0022] A sun shaft is a shaft connected to a sun gear and non-rotatably linked to it. Preferably, the sun shaft is integrally connected to the sun gear. The sun gear is part of a planetary stage of the present wind turbine gearbox.

[0023] A generator hub is a hub designed to accommodate the rotor of a wind turbine generator. It is characterized by being rotationally fixed to the rotor, or being connectable to it. Preferably, it supports the rotor. If the rotor is supported by the generator hub, all forces acting on the rotor, particularly its weight, are absorbed by the generator hub. The rotor is then supported exclusively by one or more bearings of the generator hub. In a further embodiment, the hollow shaft is rotationally fixed to the generator hub. In particular, another axial end of the hollow shaft can be joined to the generator hub. Such a connection is achieved, for example, by a bolted flange in which the hollow shaft and the generator hub are bolted together.

[0024] Preferably, the wind turbine gearbox is further developed such that the shaft runs through the generator hub. The two axial ends of the shaft are then located on opposite sides of the generator hub, while a central section of the shaft, situated between the two axial ends, is located inside or in a cavity formed by the generator hub.

[0025] In this further development, the hollow shaft extends from the connector towards the generator hub. The hollow shaft is therefore located between the connector and the generator hub. Furthermore, the shaft connector and the sun gear are located on opposite axial sides of the generator hub. Therefore, the generator hub is axially positioned between the shaft connector and the sun gear.

[0026] Preferred embodiments of the invention are illustrated in the figures. Specifically, the figures show:

[0027] Fig. 1 shows a connection between the gearbox and the generator; and

[0028] Fig. 2 shows a wave connector.

[0029] Figure 1 shows the output side of a drive train for a wind turbine. The output shaft of the gearbox is a sun shaft 101, which has a sun gear 103. The sun shaft 101 and the sun gear 103 are integrally connected. A generator hub 105 serves to accommodate a generator rotor. This hub is rotatably mounted in a gearbox housing by means of two bearings (not shown in Figure 1).

[0030] The generator hub 105 is hollow. It encloses a cavity through which the solar shaft 101 passes. The two axial ends of the solar shaft 101 are therefore located on opposite axial sides of the generator hub 105.

[0031] A first axial end of the sun shaft 101 is joined to the sun gear 103. A second axial end of the sun shaft 101, located on the opposite axial side of the generator hub 105, is joined to a hollow shaft 109 by means of a shaft connector 107.

[0032] A rotationally fixed connection between the solar shaft 101 and the rotor hub 105 is established via the hollow shaft 109. The hollow shaft 109 extends between the shaft connector 107 and the generator hub 105. It forms a screw flange 111, which is rotationally fixed to the generator hub 105.

[0033] The structure of the shaft connector 107 is shown in detail in Fig. 2. The shaft connector 107 consists of a first section 201, a second section 203, and a third section 205. The three sections 201, 203, and 205 are hollow cylindrical and run around a common axis of symmetry, which is identical to an axis of rotation of the sun shaft 101, the sun gear 103, the shaft connector 107, the hollow shaft 109, and the generator hub 105.

[0034] The first section 201 is arranged within the second section 203, or rather within a cavity enclosed by the second section 203. Its radius is correspondingly smaller than the radius of the second section 203. Thus, the first section 201 and the second section 203 enclose a gap into which an axial end of the hollow shaft 109 engages. The first section 201 and the second section 203 are identical in their axial extent with respect to the aforementioned axes. Both sections 201 and 203 extend between two radially extending planes, i.e., planes oriented orthogonally to the aforementioned axes. These two planes form the axial boundaries of sections 201 and 203.

[0035] Towards the axial side opposite the hollow shaft 109, the gap is closed by a third section 205. The section 205 extends radially between an axial end of the first section 201 and an axial end of the second section 203 and connects the two axial ends of the first section 201 and the second section 203.

[0036] The third section 205 forms a stop for the hollow shaft 109. The third section 205 positively limits the movement of the hollow shaft 109 relative to the shaft connector 107 in the axial direction.

[0037] The first section 201 and the second section 203 have pairs of coaxially aligned bores. Each pair of bores accommodates a bolt 207. The bolt 207 engages positively in the bores of the respective pair. It also engages in a bore of the hollow shaft 109. This creates a positive connection between the hollow shaft 109 and the shaft connector 107.

[0038] At an axial end opposite the third section 205, the first section 201 is integrally connected to the sun shaft 101. This connection is particularly rotationally fixed. Therefore, the sun shaft 101 is rotationally fixed to the hollow shaft 109 via the shaft connector 101 and the positive locking effect achieved by means of the bolts 207.

[0039] Each bolt is equipped with a screw 209 to prevent loss. The screw 209 is received in a through bore of the respective bolt 207, which extends axially through the bolt 207, and is screwed into a thread in the first section 201 of the shaft connector 107. The opening of the bore serves as a bearing surface for the head of the screw 209. The screw 209 is thus clamped between the opening and the thread.

[0040] Reference mark

[0041] Sun wave

[0042] sun wheel

[0043] Generator hub

[0044] Shaft connectors

[0045] Hollow shaft

[0046] screw flange

[0047] Section

[0048] Section

[0049] Section

[0050] bolt

[0051] screw

Claims

Patent claims 1. Arrangement with a shaft (103), a hollow shaft (109) and a connector (107); wherein the shaft (103) and the hollow shaft (109) are fixed together by means of the connector (107) and extend in the same axial direction from the connector (107); characterized in that the connector (107) forms a cavity which receives an axial end of the hollow shaft (109).

2. Arrangement according to claim 1; characterized in that an axial end of the shaft (101) is joined to the connector (107).

3. Arrangement according to one of the preceding claims; characterized in that the cavity and the axial end of the hollow shaft (109) are identical in shape.

4. Arrangement according to one of the preceding claims; characterized in that at least a part of the connector (107) is U-shaped in longitudinal section.

5. Arrangement according to one of the preceding claims; characterized by bolts (207) which engage in two recesses of the connector (107) and an intermediate recess of the hollow shaft (109).

6. Arrangement according to the preceding claim; characterized in that the bolts (207) are arranged at least partially rotationally symmetrically to each other.

7. Arrangement according to one of the preceding two claims; characterized by Screws (209) which are screwed through a hole in each of the bolts ()207 into a thread of the connector (107).

8. Arrangement according to one of the preceding claims; characterized in that the hollow shaft (109) consists at least partially of a composite material.

9. Wind turbine gearbox with a generator hub; characterized by an arrangement according to one of the preceding claims; wherein the shaft (101) is designed as a solar shaft; and wherein the hollow shaft (109) is rotatably connected to the generator hub.

10. Wind turbine gearbox according to the preceding claim; characterized in that Wave (101) passes through the generator hub.

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