Draining a local oil bath

Abstract

Gearbox comprising at least one bearing seat ring (103) with at least one bearing (105) and a receptacle (119) for the bearing seat ring (103); wherein the gearbox forms a local oil bath for the at least one bearing (105); wherein the bearing seat ring (103) forms a first drain (127) for the oil bath; wherein the receptacle (119) closes the first drain (127) when the bearing seat ring (103) is fixed in the receptacle (119); and wherein the receptacle (119) forms a second outlet (125) which comes into fluid contact with the first outlet (127) at least temporarily when the bearing seat ring (103) is removed from the receptacle (119); characterized in that that at least one bearing (105) is at least partially wetted by oil that is in the local oil bath.

Description

[0001] The invention relates to a transmission according to the preamble of claim 1.

[0002] In wind turbines, there is a growing trend towards structurally integrating the gearbox and generator. In such solutions, a generator rotor is supported by a gearbox output shaft. The output shaft bearings can be integrated into a bearing cassette, which can be removed from the rotor side in case of a defect. It is essential to prevent oil from leaking into the generator or nacelle. This is particularly problematic if the bearing cassette's bearings operate in a localized oil bath.

[0003] DE 35 22 600 A1 discloses a gearbox with a gearbox housing having a bore. The bore is provided in its upper region with an opening 21 which is aligned with an opening in a bearing bushing. Another opening in the bearing bushing, which is diametrically opposite the first opening 22, i.e., located in the lower region, is closed by the bore of the gearbox housing.

[0004] The invention is based on the objective of making available a transmission that is improved compared to solutions known from the prior art. In particular, maintainability is to be improved.

[0005] This problem is solved by a transmission according to claim 1. Preferred embodiments are included in the dependent claims.

[0006] The gearbox has at least one bearing seat ring. A bearing seat ring is a component that forms a bearing seat, i.e., a device for fixing at least one outer or inner bearing shell of at least one bearing. Preferably, the bearing seat ring has a basic shape that is rotationally symmetrical about an axis of rotation of the bearing. The basic shape of a body refers to the shape of an original body from which the first-mentioned body is created by eliminating individual areas, for example by inserting recesses, and / or by adding individual areas.

[0007] Furthermore, the gearbox has at least one bearing. This bearing, together with the bearing seat ring, forms a bearing assembly. An outer or inner ring of the bearing is fixed in the bearing seat ring. Preferably, an outer ring of the bearing is fixed in the bearing seat ring. The bearing can be a rolling bearing, in particular a cylindrical or tapered roller bearing.

[0008] The gearbox includes a receptacle for the bearing seat ring. This receptacle is designed to receive and securely fix the bearing seat ring to the housing. Specifically, the gearbox housing or a housing-mounted component can serve as the receptacle for the bearing seat ring.

[0009] A local oil bath is provided for the lubrication of at least one bearing. This oil bath serves as emergency lubrication, ensuring a supply of lubricant even if the regular lubricant supply is interrupted, for example, due to a defect in an electric lubricant pump.

[0010] An oil bath is a trough-shaped, that is, open-topped, reservoir of lubricant. For example, an oil sump is an oil bath formed exclusively by the gearbox housing.

[0011] A local oil bath is an oil bath separate from the oil sump. Preferably, the local oil bath is located within the gearbox housing, so that oil leaking from the local oil bath flows into the oil sump.

[0012] The local oil bath is preferably located within the bearing seat ring. The local oil bath is formed by the bearing seat ring and, if applicable, other components, such as a baffle plate.

[0013] The local oil bath is arranged such that the at least one bearing is at least partially wetted by the oil contained within it. Thus, the at least one bearing is at least partially immersed in the local oil bath. If it is a rolling bearing, its rolling elements pass through the local oil bath when the bearing rotates.

[0014] According to the invention, the bearing seat ring forms a first drain for the oil bath. Here, "drain" refers to a through hole with a slope. The hole has an inlet and an outlet. The slope is such that oil entering the drain through the inlet flows to the outlet due to the effect of gravity and exits the drain through the outlet.

[0015] The inlet of the first drain is located within the oil bath. This means that at least part of the inlet of the first drain lies below the surface of the oil that has collected in the oil bath. This is true at least when the oil level approaches an overflow.

[0016] To ensure reliable oil drainage under all conditions, the inlet of the first drain is preferably located at the bottom of the oil bath, thus forming the lowest point of the oil bath.

[0017] The receptacle for the bearing seat ring is designed, and the first drain is arranged, such that the receptacle closes the first drain when the bearing seat ring is fixed in the receptacle. The first drain is sealed oil-tight. Specifically, the receptacle closes the outlet of the first drain. When the bearing ring is fixed in the receptacle, the first drain is thus deactivated. This ensures that, during gearbox operation, the required quantity of oil for lubricating at least one bearing can collect in the oil bath.

[0018] The receptacle forms a second outlet. This outlet is arranged such that it comes into at least temporary fluid contact with the first outlet when the bearing seat is removed from the receptacle. This at least temporary fluid connection between the first and second outlets occurs when the outlet of the first outlet and an inlet of the second outlet overlap at least partially. When the bearing seat ring is removed from the receptacle, the outlet of the first outlet moves along a specific path. The second outlet is arranged such that at least a portion of the outlet of the first outlet overlaps at least a portion of the inlet of the second outlet along this path.

[0019] The fluid-conducting connection between the first and second drains ensures that the oil bath empties when the bearing seat ring is removed from the housing. This prevents oil from escaping into the environment during maintenance, assembly, or repair work.

[0020] Preferably, the second drain is designed such that the oil flowing through it is directed into the oil sump of the gearbox. This empties the local oil bath into the oil sump when the bearing seat ring is removed from the housing.

[0021] In a preferred embodiment, the bearing seat ring is removed from the receptacle in an axial direction, i.e., in the direction of the axis of rotation of the at least one bearing. Therefore, any movement of the bearing seat ring during removal from the receptacle is axial. Simultaneously, an axial offset exists between the outlet of the first oil drain and the inlet of the second oil drain when the bearing seat ring is fixed in the receptacle. Due to the axial movement of the bearing seat ring during removal from the receptacle, this axial offset decreases until at least a portion of the outlet of the first drain and at least a portion of the inlet of the second oil drain finally overlap, thus establishing the fluid-conducting connection according to the invention.

[0022] Preferably, the bearing seat ring is designed with a first cylindrical surface and the receptacle with a second cylindrical surface. A cylindrical surface is a surface that has the shape of the lateral surface of a cylinder, preferably a right circular cylinder. When the bearing seat ring is fixed in the receptacle, the first cylindrical surface and the second cylindrical surface are in contact with each other. Thus, there is planar contact between the first and second cylindrical surfaces when the bearing seat ring is fixed in the receptacle. This contact contributes to the fixation. Furthermore, the cylindrical shape of the two surfaces determines the direction of movement of the bearing seat ring when it is removed from the receptacle. If the central axis of the cylinders defining the two surfaces coincides with the axis of rotation of the bearing, this movement is axial.

[0023] In order for the fluid-conducting connection according to the invention to be established between the first outlet and the second outlet, the outlet opening of the first outlet is located, according to the further embodiment, in the first cylindrical surface and the inlet opening of the second outlet in the second cylindrical surface.

[0024] The bearing seat ring is preferably further developed with a third outlet. This serves as an overflow. Oil is drained from the oil bath through the overflow as soon as its oil level exceeds a certain height. This can be achieved by a suitable arrangement of the inlet opening of the third outlet.

[0025] The oil that overflows and flows into the third drain via its inlet is discharged via the second drain, as described in the further development. For this purpose, the third drain is fluidly connected to the second drain when the bearing seat ring is fixed in the housing. At least part of the outlet of the third drain and at least part of the inlet of the second drain overlap for this purpose. This further development is advantageous because the second drain can be used in two different ways.

[0026] In a preferred embodiment, the gearbox has an output shaft that is rotatably mounted by means of at least one bearing. This is accompanied by the arrangement of the bearing housing at the gearbox output. The advantage of such an arrangement is the easy accessibility of the bearing seat ring, which can be easily removed from its housing.

[0027] Preferred embodiments of the invention are illustrated in the figures. Matching reference numerals denote identical or functionally equivalent features. Specifically, the figures show: Fig. 1 a storage cassette in sectional view; Fig. 2 a first view of a bearing seat ring; and Fig. 3 a second view of the bearing seat ring.

[0028] The in Fig. The bearing cassette 101 shown comprises a bearing seat ring 103 and two tapered roller bearings 105. The outer ring of each tapered roller bearing 105 is fixed in the bearing seat ring 103. Its inner ring is fixed on a hollow shaft 107. This allows the hollow shaft 107 to be rotatably mounted in the bearing cassette 101.

[0029] The hollow shaft 107 is provided with internal teeth 109. These form a connection with a Fig. The external toothing of a solar shaft (not shown) forms a splined connection. In this way, the hollow shaft 107 is driven via the solar shaft. The solar shaft is an output shaft of a generator-side planetary stage 111.

[0030] The planetary stage 111 and a rotor 113 of a generator 115 are arranged on axially opposite sides of the bearing cassette 101. The rotor 113 is fixed in the hollow shaft 107 by means of a screw flange 117. The hollow shaft supports the rotor 113. This means that the rotor 113 is supported by the bearings 105. No further bearings for the rotor 113 are provided.

[0031] The bearing seat ring 103 is fixed in a housing recess 119 of a gearbox housing. To lubricate the tapered roller bearing 105, the bearing seat ring 107 forms a local oil bath. For this purpose, it has a lip 121. This lip causes oil to collect in the lower area of ​​the bearing seat ring 103.

[0032] In Fig. One overflow bore (not shown) opens into a groove 123 of the bearing seat ring 103. The housing nozzle 119 forms a cavity 125 with which the groove 123 is connected in a lubricant-conducting manner. In this way, the oil that has drained from the local oil bath is carried away.

[0033] The bearing seat ring 103 has two radially extending drain holes 127. When the bearing seat ring 107 is fixed in the housing socket 119, the drain holes 127 are closed by the housing socket 119. The drain holes 127 serve to drain the oil bath when the bearing cassette 101 is removed for maintenance or repair purposes.

[0034] For removal, the bearing cassette 101 is pulled out of the housing socket 119 in an axial movement. During this process, the drain holes 127 come into contact with the cavity 125, allowing lubricant to pass through. Consequently, any oil contained in the local oil bath is drained away via the drain holes 127 and the cavity 125.

[0035] The Fig. 2 and Fig. Figure 3 represents the bearing seat ring 107. In Fig. Figure 2 shows the drainage bores 127 and two overflow bores 201. The overflow bores 201 open, as shown in Fig. 3 visible, into groove 123. Reference sign 101 storage cassette 103 Bearing seat ring 105 tapered roller bearings 107 Hollow shaft 109 Internal gearing 111 Planetary Stage 113 Rotor 115 Generator 117 Screw flange 119 Housing nozzles 121 Lippe 123 Nut 125 cavity 127 Drainage hole 201 Overflow borehole

Claims

[1] Gearbox comprising at least one bearing seat ring (103) with at least one bearing (105) and a receptacle (119) for the bearing seat ring (103); wherein the gearbox forms a local oil bath for the at least one bearing (105); wherein the bearing seat ring (103) forms a first drain (127) for the oil bath; wherein the receptacle (119) closes the first drain (127) when the bearing seat ring (103) is fixed in the receptacle (119); and wherein the receptacle (119) forms a second outlet (125) which comes into fluid contact with the first outlet (127) at least temporarily when the bearing seat ring (103) is removed from the receptacle (119); characterized by , that that at least one bearing (105) is at least partially wetted by oil that is in the local oil bath. [2] Gearbox according to claim 1; characterized by , that the bearing seat ring (103) is removed from the receptacle (119) in an axial direction; wherein an axial offset exists between an outlet of the first drain (127) and an inlet of the second oil drain (125). [3] Gearbox according to any one of the preceding claims; characterized by , that the bearing seat ring (103) forms a first cylindrical surface and the receptacle (119) forms a second cylindrical surface; wherein the first cylindrical surface and the second cylindrical surface are in contact when the bearing seat ring (103) is fixed in the receptacle (119); wherein the outlet of the first drain (127) is located in the first cylindrical surface and the inlet of the second drain (125) is located in the second cylindrical surface. [4] Gearbox according to any one of the preceding claims; characterized by , that the bearing seat ring (103) has a third outlet (123, 201) designed as an overflow; wherein the third flow (123, 201) is fluidly connected to the second flow (125) when the bearing seat ring (103) is fixed in the receptacle (119). [5] Gearbox according to any one of the preceding claims; characterized by an output wave (107); wherein the output shaft (107) is supported by means of at least one bearing (105).

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