Transfer of lubricant into the interior of a hollow shaft

Abstract

The invention relates to an arrangement with a means (101) fixed to a housing, with a hollow shaft (103) rotatably mounted in the means (101) fixed to the housing, and with a lubricating point (107, 203) at least partially located in the interior of the hollow shaft (103). The means (101) fixed to the housing has a ring (113), which together with the outer lateral surface of the hollow shaft (103) encloses a hollow space; wherein the ring (113) has one or more bores (113) which each open out into the hollow space; and wherein the hollow shaft (103) has one or more bores (117) which each open out into the interior of the hollow shaft (103) and into the hollow space.

Description

[0001] Transfer of lubricant into the interior of a hollow shaft

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

[0003] In this context, EP 1 488 139 B1 shows a planetary stage of a gearbox with a rotating planet carrier and a stationary ring gear. The output of the planetary stage is via a sun. Planets and planetary bearings are mounted on planetary shafts that rotate together with the planet carrier. A stationary pump feeds oil through stationary oil lines and oil conditioning elements (i.e., coolers, filters, etc.). A circular ring, e.g. made of polyamide, has a U-shaped profile and is mounted on a rear side of the planet carrier. This ring fits into a machined annular groove in the stationary housing. Since the ring is fixed relative to the rotating planet carrier, it consequently rotates relative to the stationary housing.The combination of the U-shaped ring and the ring groove in the housing creates a channel through which oil can flow through holes in a locking plate of the planetary carrier into cavities in the back of the planetary shafts. From here, the oil moves through the holes in the planetary shafts to the planetary bearings. Because the U-shaped ring doesn't fit perfectly into the milled groove in the housing, some oil leakage and pressure drop occur.

[0004] The invention is based on the object of transferring oil between a housing-fixed means and a lubrication point located inside a hollow shaft. This object is achieved by an arrangement according to claim 1. Preferred developments are contained in the subclaims and will become apparent from the following description.

[0005] The arrangement comprises the means fixed to the housing, the hollow shaft, and the lubrication point. The means fixed to the housing is a means that is fixed, i.e., is arranged in a housing without the possibility of relative movement. In particular, the housing itself is a means fixed to the housing. The hollow shaft is rotatably mounted in the means fixed to the housing. It is therefore rotatable relative to the means fixed to the housing. The bearing is provided by means of one or more bearings that support the hollow shaft in the means fixed to the housing. In particular, an outer ring of the bearings can be fixed in the means fixed to the housing, while the inner ring is fixed on the hollow shaft.

[0006] A hollow shaft is characterized by its hollow interior, meaning it encloses a cavity. This cavity is referred to as the interior of the hollow shaft.

[0007] The hollow shaft can, in particular, be designed as the output shaft of the transmission and / or be connected or connectable in a rotationally fixed manner to a rotor of a generator. The hollow shaft is preferably rotationally symmetrical with respect to its axis of rotation. Thus, its interior is also rotationally symmetrical with respect to the axis of rotation.

[0008] Preferably, the interior of the hollow shaft opens into the two end faces of the hollow shaft. This means that both end faces each have an opening through which the interior is accessible from the outside.

[0009] A lubrication point refers to a device that requires lubricant. To prevent wear, lubricant must be supplied to the device.

[0010] The arrangement according to the invention is preferably part of a transmission. This implies that the housing-fixed means, the hollow shaft, and the lubrication point are also part of the transmission. It is preferably a wind turbine transmission.

[0011] According to the invention, the housing-fixed means comprises a ring. The ring can be connected to the housing-fixed means in one or more pieces.

[0012] A ring is a body shaped like a toroid. This is a surface of revolution with a continuous recess through which the rotational axis runs. The ring encloses the hollow shaft so that the hollow shaft extends through the recess of the ring, with a portion of the hollow shaft located in the recess. The ring, together with an outer surface of the hollow shaft, encloses a hollow space. The hollow space is preferably rotationally symmetrical with respect to a rotational axis of the hollow shaft and the aforementioned rotational axis of the ring.

[0013] The ring has one or more holes, each of which opens into the cavity. Holes generally refer to through holes. A through hole is a hole with exactly two openings. It can, in particular, be a cylindrical hole, created, for example, by drilling.

[0014] The hollow shaft also has one or more holes. These lead into the interior of the hollow shaft and into the cavity. The holes in the hollow shaft thus connect the interior of the hollow shaft and the cavity in an oil-conducting manner.

[0015] The bores in the ring and the hollow shaft serve as lubricant lines. Because they open into the cavity, the cavity forms a lubricant-conducting connection between the ring and the hollow shaft, or between their bores. Lubricant can be introduced into the cavity through the bores in the ring. From the cavity, the lubricant flows through the bores in the hollow shaft into the interior of the hollow shaft. This supplies the lubrication point inside the hollow shaft with oil.

[0016] The invention is advantageous because it can be implemented without significant structural changes to a conventional arrangement comprising a housing-fixed means, a hollow shaft rotatably mounted in the housing-fixed means, and a lubrication point located inside the hollow shaft. Only the bores and the ring are required to supply the lubrication point with oil. Both the bores and the ring are comparatively simple and inexpensive to manufacture.

[0017] Preferably, the arrangement is further developed with a shaft and a spline. A spline is a multiple-carriage connection consisting of two splines. The splines mesh with each other in such a way that they are connected in a rotationally fixed manner. Their central or rotational axes coincide.

[0018] The spline connects the shaft and the hollow shaft in a rotationally fixed manner. Specifically, one spline of the spline is rotationally fixed to the shaft. The other spline is rotationally fixed to the hollow shaft. In particular, the shaft and / or the hollow shaft can form the respective spline as a single piece.

[0019] The spline provides the aforementioned lubrication point. This design allows the spline to be supplied with lubricant even though it is located at least partially inside the hollow shaft and is therefore difficult to access.

[0020] The arrangement can also be further developed with a feedthrough tube and at least one bearing. A feedthrough tube, also called a pitch tube, is a tube for passing through supply lines, such as electrical cables and / or lubricant lines.

[0021] The at least one bearing supports the feedthrough tube in the hollow shaft. This allows the hollow shaft to rotate relative to the feedthrough tube. In particular, the feedthrough tube can be fixed to the housing, so that no relative movement is possible between the feedthrough tube and the housing.

[0022] The bearing forms the lubrication point according to the design. This design allows the bearing to be supplied with oil even though it is located at least partially inside the hollow shaft and is therefore difficult to access.

[0023] In a preferred embodiment, the ring does not touch the outer surface of the hollow shaft. Preferably, one or more gaps extend between the ring and the outer surface of the hollow shaft. These gaps can be flat or designed as labyrinth seals. This design results in an oil leak between the ring and the outer surface of the hollow shaft, the size of which depends on the design of the gaps. The oil leak is tolerated in favor of wear-free operation.

[0024] Preferably, the arrangement is further developed with at least two bearing assemblies. These support the hollow shaft rotatably in the housing-fixed component. According to the further development, the hollow space is arranged axially between the bearing assemblies. This is advantageous because the bearing assemblies are lubricated by the aforementioned oil leak.

[0025] The hollow shaft is preferably further developed with at least one hydrodynamically active means. This is a movable means designed to build up hydrodynamic pressure. The hydrodynamic pressure is generated by a hydrodynamic effect due to the movement of the means. In this case, the means moves due to a rotation of the hollow shaft. Preferably, the means is connected to the hollow shaft in a rotationally fixed manner. In particular, the hollow shaft can form the means in one piece.

[0026] According to the further development, when the hollow shaft rotates, the means builds up a hydrodynamic pressure that acts on at least one opening of the hollow shaft's bores. This hydrodynamic pressure causes the oil to be pumped through the hollow shaft's bores from the hollow space into the interior of the hollow shaft.

[0027] The means is preferably designed as a recess or pocket. This is preferably located in front of the at least one opening in the direction of rotation of the shaft. Preferably, a raised portion or step is also located behind the at least one opening in the direction of rotation of the shaft.

[0028] Preferred developments of the invention are illustrated in the figures. Corresponding reference numerals indicate identical or functionally equivalent features. Specifically, Fig. 1 shows an arrangement for supplying oil to a spline;

[0029] Fig. 2 shows an arrangement for supplying oil to a bearing of a feedthrough pipe;

[0030] Fig. 3

[0031] Fig. 4 a detailed view with labyrinth seal; and

[0032] Fig. 5 a hydrodynamically effective pocket.

[0033] The arrangement shown in Figure 1 comprises part of a gear housing 101, a hollow shaft 103 and a sun shaft 105.

[0034] The hollow shaft 103 and the sun shaft 105 each form part of a spline 107. The hollow shaft 103 and the sun shaft 105 are connected to one another in a rotationally fixed manner by means of the spline 107. The spline 107 is located inside the hollow shaft 103. Accordingly, the hollow shaft 103 forms an internal toothing associated with the spline 107, and the sun shaft 105 forms an external toothing associated with the spline 107. The internal toothing and the external toothing mesh with one another and are thus connected to one another in a rotationally fixed manner.

[0035] The hollow shaft 103 is rotatably mounted in the gear housing 101 by means of a first bearing 109 and a second bearing 111.

[0036] A lubricant transfer ring 113 is located axially between the first bearing 109 and the second bearing 111. This is part of the gearbox housing 101. A lubricant line 115 passes through the wall of the gearbox housing 101 and the lubricant transfer ring 113.

[0037] Another lubricant line 117 is formed by the hollow shaft 103. The lubricant line 117 connects an outer surface of the hollow shaft 117 to a cavity inside the hollow shaft 117 in a lubricant-conducting manner. To supply the spline 107 with lubricant, the lubricant is introduced into the lubricant line 115 of the gear housing 101. At the lubricant transfer point 113, the lubricant enters the lubricant line 117 of the hollow shaft 103. The lubricant line 117 introduces the lubricant into the cavity 117 formed by the hollow shaft.

[0038] The arrangement shown in Figure 2 differs from the arrangement in Figure 1 in that, instead of the sun shaft 105 and the spline 107, it has a feedthrough tube 201 and a third bearing 203. The feedthrough tube 201 is rotatably mounted in the hollow shaft 103 by means of the third bearing 203. The third bearing 203 is located in the cavity formed by the hollow shaft 103. Therefore, analogous to the spline 107, it is supplied with lubricant via the lubricant lines 115, 117 and the lubricant transfer ring 113.

[0039] Figure 3 illustrates the structure of the lubricant transfer ring 113. The lubricant transfer ring 113 is provided with a groove 301. This groove is open radially inward toward a rotational axis of the hollow shaft 103. Together with an outer circumferential surface of the hollow shaft 103, the groove 301 encloses a cavity. This cavity serves to transfer lubricant from the lubricant line 115 of the transmission housing 101 into the lubricant line 117 of the hollow shaft 103.

[0040] On both sides of the groove 301, a first gap 303 and a second gap 305 extend between the lubricant transfer ring 113 and the hollow shaft 103. Lubricant exits the cavity formed by the groove 301 and the outer surface of the hollow shaft 103 through the first gap 303 and the second gap 305. Therefore, there is no friction between the lubricant transfer ring 113 and the hollow shaft 103. Accordingly, no wear occurs.

[0041] To minimize leaks due to escaping lubricant, the first gap 303 and the second gap 305 can be designed as labyrinth seals, as shown in Figure 4. The sectional view of Figure 5 shows that the hollow shaft 103 has a pocket 501. The depth of the pocket 501 increases continuously towards the lubricant line 117. As a result, when the hollow shaft 103 rotates, a hydrodynamic effect occurs with an increase in the lubricant pressure at the opening of the lubricant line 117. The increased lubricant pressure leads to a pumping effect that pumps lubricant through the lubricant line 117 into the interior of the hollow shaft 113.

[0042] Reference symbol

[0043] Gearbox housing hollow shaft

[0044] Sun shaft spline first bearing second bearing lubricant transfer ring lubricant line lubricant line feed-through pipe third bearing

[0045] Groove first gap second gap pocket

Claims

Patent claims 1. Arrangement with a housing-fixed means (101), a hollow shaft (103) rotatably mounted in the housing-fixed means (101), and a lubrication point (107, 203) located at least partially inside the hollow shaft (103); characterized in that the housing-fixed means (101) has a ring (113) which encloses a cavity with the outer cylindrical surface of the hollow shaft (103); wherein the ring (113) has one or more bores (113) which each open into the cavity; and wherein the hollow shaft (103) has one or more bores (117) which each open into the interior of the hollow shaft (103) and into the cavity.

2. Arrangement according to claim 1; characterized by a shaft (105); and a splined connection (107) wherein the shaft (105) and the hollow shaft (103) are connected to each other in a rotationally fixed manner by the splined connection (107); and wherein the splined connection (107) forms the lubrication point.

3. Arrangement according to claim 1; characterized by a through tube (201 ) and at least one bearing (203) with which the through tube (201 ) is supported in the hollow shaft (103); wherein the bearing (203) forms the lubrication point.

4. Arrangement according to one of the preceding claims; characterized in that the ring (113) does not touch the outer lateral surface.

5. Arrangement according to the preceding claim; characterized by one or more labyrinth seals that seal the ring (113) against the outer surface of the casing.

6. Arrangement according to one of the preceding claims; characterized by at least two bearing arrangements (109, 111) with which the hollow shaft (103) is rotatably mounted in the housing-fixed component (101); wherein the cavity is arranged axially between the bearing arrangements (109, 111).

7. Arrangement according to one of the preceding claims; characterized in that the hollow shaft (103) and / or the ring (113) has at least one hydrodynamically effective means (501) which is configured to build up a hydrodynamic pressure acting on at least one opening of the bores (117) of the hollow shaft (103) when the hollow shaft (103) is rotated.

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