Interlocking spline

Abstract

Planetary gear with at least one sun gear and at least one sun shaft (101); wherein the sun wheel and the sun shaft (101) are connected to each other in a rotationally fixed manner; characterized by an arrangement with a first toothing (103) and a second toothing; wherein the first tooth (103) and the second tooth form a splined connection; characterized in that a first tooth (105) and a second tooth of the first toothing (103) taper in an axial direction; wherein a tooth (201) of the second tooth engages in a space between the first tooth (105) and the second tooth; wherein the tooth (201) of the second tooth tapers in the opposite direction; and wherein the solar wave (101) forms the first toothing (103).

Description

[0001] The invention relates to a planetary gear unit according to the preamble of claim 1.

[0002] Interlocking gears are known from the prior art. These are described in the standard DIN 5480. In an interlocking gear, an external tooth and an internal tooth mesh with each other, creating a rotationally fixed connection.

[0003] To ensure a proper axial fit, additional means are required. These increase the effort required during assembly.

[0004] DE 10 2005 035 706 A1 discloses a shaft-hub connection arrangement with interlocking torque-transmitting teeth on the shaft and in the hub, wherein the shaft (3) has external teeth between a free first end and a connection-side second end of the shaft, and the hub has internal teeth between a free first end and a connection-side second end of the hub. The tooth widths or tooth gap widths of at least one of the two components, namely the shaft or the hub, over the length of the teeth between the first and the second end are designed such that a fit formed at the beginning of the joining process between the teeth at the free first ends between the shaft and the hub has a lower contact pressure than a fit formed at the end of the joining process between the teeth at the free first end of one component and the connection-side second end of the other component.

[0005] From DE 10 2011 057 010 A1, an arrangement is disclosed comprising a shaft and a hub connected to each other via a shaft-hub connection. The shaft is axially enclosed by the hub, whereby the teeth of the shaft engage with the teeth of the hub and torques can be transmitted. The shaft or the hub has first teeth whose tooth flanks are straight, and the hub or the shaft has second teeth whose tooth flanks are twisted by a helical angle on the surface of the element. The second teeth have a crown on at least one side along their tooth flanks.

[0006] DE 91 16 324 U1 discloses an arrangement with a profile toothing between a shaft journal and a hub. The profile toothing has tapered tooth widths at its front end, which is the end joined during the assembly process, while maintaining an unchanged tooth height.

[0007] DE 635 934 A relates to a splined shaft connection with a plurality of splines, generally extending longitudinally and spaced at intervals around the circumference, which are separated by tooth-shaped gaps and have a uniformly conical width in the longitudinal direction. At least one side of each spline has a helical shape.

[0008] DE 10 2009 017 956 A1 teaches a compensating coupling for the torque-transmitting connection of two shafts with the possibility of compensating for axial, angular or lateral misalignments by means of a compensating element, wherein the coupling is designed to be axially pluggable on at least one side, with a plug-in hub carrying external teeth, which has on one side facing the centering hub an axially projecting projection beyond the end of the cams, the outer diameter of which is slightly smaller than the base circle of the centering hub and thus ensures radial pre-centering of these two parts to each other before the teeth of the plug-in hub and centering hub are joined.

[0009] The invention is based on the objective of making a planetary gear available while circumventing the disadvantages inherent in solutions known from the prior art. In particular, the planetary gear should be easy and therefore inexpensive to assemble.

[0010] This problem is solved by a planetary gear according to claim 1. Preferred embodiments are included in the dependent claims.

[0011] The planetary gear set comprises at least one sun gear and at least one sun shaft. The sun gear and the sun shaft are connected to each other in a rotationally fixed manner.

[0012] According to the invention, the planetary gear comprises an arrangement with a first gear and a second gear. The sun shaft forms the first gear.

[0013] The two teeth form a splined connection. The first tooth can be internal and the second external, or the first external and the second internal. If the first tooth is internal, the second tooth is external. Conversely, if the first tooth is external, the second tooth is internal.

[0014] The first and second teeth of the first gear taper in an axial direction. This direction, as well as a second direction opposing it, runs parallel to a central axis of the first gear, which in turn corresponds to a central axis of the second gear. If the first and second gears are rotatably mounted, the central axis coincides with an axis of rotation of both gears. Any two teeth of the first gear or the second gear can be aligned by rotating them around the central axis.

[0015] The tapering of the first and second teeth in the first direction is equivalent to a reduction in the cross-sectional area of ​​the first and second teeth in the first direction. This means that the cross-sectional areas of the first and second teeth decrease strictly monotonically in the first direction.

[0016] The cross-sectional area is defined as the area in which a plane extending radially, i.e., orthogonally to the central axis, intersects the first tooth and the second tooth, respectively. If this plane shifts in the first direction, the area of ​​the cross-sectional surface decreases.

[0017] The cross-sectional area is bounded by a tip circle and a root circle of the first tooth, both lying in the aforementioned plane. Furthermore, the area is bounded by lines of intersection where the flanks of the first tooth and the second tooth intersect the plane.

[0018] A tooth of the second occlusion engages in a space between the first and second teeth. This implies that the first and second teeth are adjacent and form a common tooth base. A flank of the first tooth and a flank of the second tooth are in opposition to each other.

[0019] Corresponding to the tapered design of the first and second teeth, the gap between them tapers in the opposite direction, i.e., in the second direction. The tooth of the second gear is designed such that its flanks are in at least line contact with one flank of the first tooth and one flank of the second tooth. Therefore, the tooth of the second gear also tapers in the second direction.

[0020] The tapering of the tooth of the second gear in the second axial direction is equivalent to a reduction in the cross-sectional area of ​​this tooth in the second direction. The cross-sectional area of ​​the tooth of the second gear is therefore strictly monotonically increasing in the first direction.

[0021] The cross-sectional area is defined as the area in which a plane extending radially, i.e., orthogonally to the central axis, intersects the tooth of the second gear tooth. If this plane shifts in the second direction, the area of ​​the cross-sectional surface decreases.

[0022] The cross-sectional area is bounded by a tip circle and a root circle of the second tooth, both lying in the aforementioned plane. Furthermore, the area is bounded by lines of intersection where the flanks of the second tooth intersect the plane.

[0023] The inventive design of the gear teeth allows the transmission of an axial force acting in the first direction from the first gear tooth to the second gear tooth. Conversely, an axial force acting in the second direction can be transmitted from the second gear tooth to the first gear tooth. Means for axially fixing the first and second gear teeth are not required.

[0024] The first tooth, the second tooth, and the tooth of the second tooth taper across their entire width in a preferred development. The width of each tooth extends in the axial direction. According to this development, the first tooth, the second tooth, and the tooth of the second tooth each taper from a first end face to a second end face of the first tooth. The second end face of the first tooth is located in the first direction relative to the first end face. Similarly, the second end face of the second tooth is located in the second direction relative to the first end face.

[0025] The tapered sections of the first tooth, the second tooth, and the tooth of the second gear are particularly evident in tangential longitudinal sections. Preferably, the flanks of the first tooth, the second tooth, and the tooth of the second gear each form antiparallel lines in at least one tangential longitudinal section. This means that the lines of intersection of any two flanks of the first tooth, the second tooth, and the tooth of the second gear are antiparallel. In a preferred embodiment, the first tooth, the second tooth, and the tooth of the second gear each have a trapezoidal shape in at least one tangential longitudinal section.

[0026] A tangential longitudinal section is a longitudinal section that is oriented tangentially. Tangential orientation refers to an orientation orthogonal to a radially extending line. A radially extending line, in turn, intersects the aforementioned central axis and is oriented orthogonally to it.

[0027] In a preferred embodiment, the central axes of the first tooth, the second tooth, and the tooth of the second gear are each skew to the central axis. This means that the central axis of each tooth and the central axes of the first and second gears are antiparallel and do not intersect. This skew orientation relieves the splined gear of constant axial forces that can be caused, for example, by helical working gears.

[0028] In a further preferred development, the above statements apply to each tooth of the first tooth and each tooth of the second tooth. In particular, each tooth of the first tooth tapers in the first direction, and each tooth of the second tooth tapers in the opposite direction.

[0029] The planetary gear according to the invention preferably comprises at least two planetary stages. A first of the two planetary stages includes the sun gear.

[0030] In a preferred embodiment of the planetary gear, a second of the two planetary stages features a planet carrier that forms the second gear teeth. The sun shaft is thus positively connected to the planet carrier via the first and second gear teeth. Such a gear is used, for example, as a gearbox in a wind turbine.

[0031] 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. an axially tapered external toothing; and Fig. 2 a tangential longitudinal section.

[0032] According to Fig. Figure 1 has a sun shaft 101 with an external toothing 103, which is part of a splined connection. The external toothing 103 can therefore be divided into a Fig. 1. Internal toothing not shown, so that it forms a positive-locking, rotationally fixed connection with it.

[0033] The external toothing 103 has a large number of teeth, of which in Fig. Figure 1 shows, by way of example, a first tooth 105, a second tooth 107, and a third tooth 109. The profile of all teeth of the external gearing 103 tapers in the axial direction. This is shown in Fig. Figure 1 shows an example of the first tooth 105. In particular, the profile of the second tooth 107 and the third tooth 109 also tapers.

[0034] The external toothing 103 is helical. Thus, the central axes of the individual teeth of the external toothing 103 are skew to a central axis 111 of the sun shaft 101. In particular, a central axis 113 of the first tooth 105 is skew to the central axis 111.

[0035] The in Fig. The tangential longitudinal section shown in Figure 2 includes, in addition to the first tooth 105 of the external gearing 103, teeth 201 of the internal gearing, which together with the external gearing 103 form the interlocking teeth. The teeth 201 taper in the opposite direction to the first tooth 105. In this way, the first tooth 105 and the teeth 201 of the external gearing wedge themselves together. Reference sign 101 Sun Wave 103 External gearing 105 first tooth 107 second tooth 109 third tooth 111 middle salmon 113 Central axis 201 Tooth of an external tooth

Claims

[1] Planetary gear with at least one sun gear and at least one sun shaft (101); wherein the sun wheel and the sun shaft (101) are connected to each other in a rotationally fixed manner; characterized by an arrangement with a first toothing (103) and a second toothing; wherein the first tooth (103) and the second tooth form a fitting tooth; characterized by , that a first tooth (105) and a second tooth of the first toothing (103) taper in an axial direction; wherein a tooth (201) of the second tooth engages in a space between the first tooth (105) and the second tooth; wherein the tooth (201) of the second tooth tapers in the opposite direction; and wherein the solar wave (101) forms the first toothing (103). [2] Planetary gear according to claim 1; characterized by, that the first tooth (105), the second tooth and the tooth (201) of the second tooth taper over their entire width. [3] Planetary gear set according to any one of the preceding claims; characterized by , that the first tooth (105), the second tooth and the tooth (201) of the second toothing are each trapezoidal in at least one tangential longitudinal section. [4] Planetary gear set according to any one of the preceding claims; characterized by , that the central axes (113) of the first tooth (105), the second tooth and the tooth (201) of the second toothing are each skew to a central axis (111) of the first toothing (103) and the second toothing. [5] Planetary gear set according to any one of the preceding claims; characterized by , that each tooth of the first toothing (103) tapers in the direction; wherein each tooth of the second toothing tapers in the opposite direction. [6] Planetary gear set according to any one of the preceding claims; characterized by at least one planet carrier; wherein the planet carrier forms the second interlocking of the arrangement.

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