Sequentially arranged planet gears

Abstract

The invention relates to a transmission arrangement (101, 201, 301, 401, 501) having a rotatable first planet carrier (107), having a first planet gear (103) mounted rotatably in the first planet carrier (107), having a second planet gear (105), having a rotationally fixed ring gear (109) which meshes with a first toothing (103a) of the first planet gear (103), and having a rotatable sun gear (117). A second toothing (103b) of the first planet gear (105) is rotationally operatively connected to the sun gear (117) via the second planet gear (105).

Description

[0001] Sequentially arranged planetary gears

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

[0003] Such a gear arrangement is known from DE 10 2014 226 046 B4. This document discloses a planetary gear with a first gearing, a second gearing, and a third gearing. The planetary gear is rotatably mounted in a rotatable planet carrier. The first gearing meshes with a non-rotatable ring gear, the second gearing meshes with a rotatable sun gear, and the third gearing meshes with a rotatable ring gear.

[0004] The invention is based on the object of providing a transmission arrangement that is improved over the prior art. This object is achieved by a transmission arrangement according to claim 1. Preferred developments are contained in the subclaims and will become apparent from the following description.

[0005] A gear assembly is an arrangement for use in a transmission. A gear assembly can refer to part of the transmission or the entire transmission.

[0006] The gear assembly according to the invention is preferably intended for use in a wind turbine. It is therefore preferably a wind turbine gearbox or a part thereof.

[0007] The transmission arrangement according to the invention comprises a first planetary carrier, a first planetary gear, a second planetary gear, a first ring gear, and a sun gear. The first planetary carrier and the sun gear are rotatable. This means that the first planetary carrier and the sun gear are rotatably mounted relative to a housing of the transmission. In particular, they can be rotatably mounted in the housing or in a structure fixed to the housing. The first ring gear is rotationally fixed. This means that the first ring gear is fixed in a rotationally fixed manner relative to the housing of the transmission. The ring gear is thus rotationally fixed in the housing or in a structure fixed to the housing.

[0008] The first planet carrier, the first ring gear, and the sun gear are arranged coaxially with each other. Thus, the rotational axis of the first planet carrier and the rotational axis of the sun gear coincide. The two rotational axes also coincide with the center axis of the first ring gear.

[0009] The first planet gear is rotatably mounted in the first planet carrier. It is rotatable relative to the planet carrier. Its axis of rotation is spaced from a rotational axis of the planet carrier. Preferably, the axes of rotation of the first planet gear and the first planet carrier run parallel to each other. The axis of rotation of the first planet gear is immobile relative to the first planet carrier. Upon rotation of the first planet carrier, the axis of rotation of the first planet gear consequently moves in an orbit around the axis of rotation of the first planet carrier.

[0010] The first planetary gear has a first toothing and a second toothing. The first toothing and the second toothing of the first planetary gear are designed as external toothings. They are aligned coaxially with each other and are non-rotatable relative to each other. Preferably, they are connected to each other as a single piece. In particular, the entire first planetary gear can be designed as a single piece.

[0011] The first ring gear, or rather its toothing, meshes with the first toothing of the first planetary gear. The toothing of the first ring gear is accordingly designed as an internal toothing.

[0012] According to the invention, the second planetary gear forms a rotationally effective connection between the second toothing of the first planetary gear and the sun gear. Two rotatably or pivotably mounted members are rotationally effective connected to one another if a bijective relationship exists between a physical quantity describing a rotation or pivoting of the first member and a physical quantity describing a rotation or pivoting of the second member. In particular, a linear relationship can exist between the two quantities. The physical quantity can be, for example, an angle of rotation, an angular velocity, a torque, or an angular acceleration.

[0013] In this case, the second planet gear represents a bijective relationship between a physical quantity describing a rotation of the second toothing of the first planet gear and a physical quantity describing a rotation of the sun gear. The rotation of the second toothing of the first planet gear is transmitted via the second planet gear to the sun gear, or the rotation of the sun gear is transmitted in the opposite direction via the second planet gear to the second toothing of the first planet gear. As a result, there are also rotationally effective connections between the second toothing of the first planet gear and the second planet gear, as well as between the second planet gear and the sun gear. Thus, there is a bijective relationship between a quantity describing a rotation of the second toothing of the first planet gear and a physical quantity describing a rotation of the second planet gear.Another bijective relationship exists between the physical quantity that describes the rotation of the second planetary gear and the physical quantity that describes the rotation of the sun gear.

[0014] By interposing the second planetary gear in accordance with the invention in the rotationally active connection between the second toothing of the first planetary gear and the sun gear, a higher gear ratio can be achieved compared to a direct coupling of the second toothing of the first planetary gear with the sun gear. At the same time, power loss is reduced, thus improving the efficiency of the transmission arrangement.

[0015] The first planetary carrier can be connected in a rotationally fixed manner to a shaft that drives the planetary carrier or is driven by the planetary carrier. In a preferred embodiment, however, the drive is provided by a second ring gear. This second ring gear is rotatable relative to the transmission housing. In particular, it can be rotatably mounted in the housing or in a structure fixed to the housing. Like the gearing of the first ring gear, the gearing of the second ring gear is also designed as an internal gearing.

[0016] According to a further development, the first planetary gear has a third gearing configured as an external gearing. This gearing is arranged coaxially with the first gearing and the second gearing of the first planetary gear and is non-rotatable relative to the first gearing and the second gearing of the first planetary gear. In particular, the third gearing can be integrally connected to the first gearing and the second gearing.

[0017] The teeth of the second ring gear mesh with the third teeth of the first planet gear. This allows a drive torque to be applied to the first planet carrier via the second ring gear and the first planet gear, or conversely, an output torque to the second ring gear via the first planet carrier and the first planet gear.

[0018] The further development of coupling the first planet carrier with the second ring gear via the third toothing of the first planet gear is advantageous because the transmission ratio can be increased even further with reduced power loss.

[0019] In a preferred embodiment, the second toothing of the second planetary gear meshes directly with the sun gear or with its toothing.

[0020] Similarly, in a preferred embodiment, the second toothing of the first planetary gear meshes directly with the first toothing of the second planetary gear. This results in a particularly simple design of the gear arrangement. This is especially true in combination with a further development of the second toothing of the second planetary gear such that it meshes with the sun gear.

[0021] In an alternative preferred development, a rotatable intermediate gear is provided. This rotatably connects the second toothing of the first planetary gear with the first toothing of the second planetary gear. It establishes a bijective relationship between a physical quantity that describes a rotation of the second toothing of the first planetary gear and a physical quantity that describes a rotation of the first toothing of the second planetary gear. The rotation of the second toothing of the first planetary gear is transmitted via the intermediate gear to the first toothing of the second planetary gear, or the rotation of the first toothing of the second planetary gear is transmitted in the opposite direction via the intermediate gear to the second toothing of the first planetary gear.

[0022] The intermediate gear is rotatable. This means it can rotate relative to the transmission housing. It is arranged coaxially with the first planet carrier, the sun gear, and the second ring gear. This means that the rotational axes of the first planet carrier, the sun gear, and the second ring gear coincide.

[0023] The intermediate gear has a first toothing and a second toothing. These are arranged coaxially to one another and cannot be rotated relative to one another. In particular, the first toothing and the second toothing of the intermediate gear can be integrally connected to one another.

[0024] The first gear and the second gear can each be internal or external gears. The first gear can be external and the second gear internal. Alternatively, the first gear can be internal and the second gear external. It is also possible to implement both gears as external gears or both gears as internal gears.

[0025] According to the further development, the second toothing of the first planetary gear meshes with the first toothing of the intermediate gear, whereby the second toothing of the intermediate gear meshes with the first toothing of the second planetary gear.

[0026] The intermediate gear allows the first planetary gear and the second planetary gear to be decoupled from the design. In particular, the sizes of their gear teeth are no longer directly dependent on each other. This opens up additional design freedom. This allows the gear arrangement to be made more compact and / or more powerful.

[0027] In a preferred embodiment, the second planetary gear, like the first planetary gear, is rotatably mounted in the first planetary carrier. A mounting of the second planetary gear in the first planetary gear is necessary if no intermediate gear is present.

[0028] The intermediate gear enables a preferred development with a second planet carrier rotatable relative to the first planet carrier. An axis of rotation about which the first planet carrier and the second planet carrier are rotatable relative to one another is preferably identical to the axis of rotation of the first planet carrier, the sun gear, and the second ring gear.

[0029] There are several options for connecting the second planetary carrier. In a preferred embodiment, the second planetary carrier can be connected to the second ring gear in a rotationally fixed manner.

[0030] In an alternatively preferred development, however, the second planet carrier is rotatable relative to the second ring gear. It is furthermore further developed to be rotatable relative to the sun gear and the intermediate gear. In such a development, the second planet carrier is designed to be approximately rotationally fixed, i.e., it is rotationally fixedly coupled to the housing of the transmission or a component fixed to the housing. Alternatively, it is rotatable relative to the housing and is or can be coupled rotationally fixedly to a component outside the transmission arrangement that is also rotatable relative to the housing.

[0031] Preferred embodiments of the invention are illustrated in the figures. Corresponding reference numerals indicate identical or functionally equivalent features. In detail:

[0032] Fig. 1 shows a planetary gear; Fig. 2 shows a planetary gear with a stepped intermediate gear;

[0033] Fig. 3 a planetary gear with cylindrical intermediate gear;

[0034] Fig. 4 shows an alternative arrangement of the intermediate gear; and

[0035] Fig. 5 a planetary gear.

[0036] The planetary gear 101 shown in Figure 1 has a first planetary gear 103 and a second planetary gear 105. The first planetary gear 103 forms three gear sets—a first gear set 103a, a second gear set 103b, and a third gear set 103c. The second planetary gear 105 forms two gear sets—a first gear set 105a and a second gear set 105b.

[0037] Both planetary gears 103, 105 are rotatably mounted in a single planetary carrier 107. The planetary carrier 107 is rotatable relative to a gear housing 109.

[0038] The third toothing 103c of the first planetary gear 103 meshes with the toothing of a first ring gear 111. The first ring gear 111 is rotatable relative to the gear housing 109. It is non-rotatably connected to a shaft via a cage 113.

[0039] A toothing of a second ring gear 115 meshes with the first toothing 103a of the first planet gear 103. The second ring gear 115 is arranged fixed to the housing, i.e., is connected in a rotationally fixed manner to the transmission housing 109.

[0040] The second toothing 103b of the first planetary gear 103 meshes with the first toothing 105a of the second planetary gear 105. The second toothing 105b of the second planetary gear 105, in turn, meshes with a sun gear 117 rotatable relative to the transmission housing 109.

[0041] The planetary gears 201, 301, 401, 501 shown in Figures 2 to 5 differ from the planetary gear 101 shown in Figure 1 by an intermediate gear 203. The intermediate gear 203 is rotatable relative to the gear housing 109. It has a first toothing 203a and a second toothing 203b. The first toothing 203a of the intermediate gear 203 meshes with the second toothing 103b of the first planetary gear 103. The second toothing 203b of the intermediate gear

[0042] 203 meshes with the first toothing 105a of the second planet gear 105.

[0043] The first planetary gear 103 and the second planetary gear 105 are each present in multiple versions. The versions of the first planetary gear 103 and the versions of the second planetary gear 105 are each arranged rotationally symmetrically to one another with respect to a common axis of rotation of the planetary carrier 107, the second ring gear 111, the sun gear 117, and the intermediate gear 203. The second gear teeth 103b of the first planetary gear 103 each mesh with the first gear tooth 203a of the intermediate gear 203. Similarly, the first gear teeth 105a of the second planetary gear 105 mesh with the second gear tooth 203b of the intermediate gear 203. As a result, the intermediate gear 203 is supported by the second gear teeth 103b of the first planetary gear 103 and the first gear teeth 105a of the second planetary gear 105, so that it does not require a separate bearing.

[0044] In contrast to Figure 1, the second planetary gear 105 shown in Figure 2 is not mounted in the first planetary carrier 107, but in a second planetary carrier 205. The second planetary carrier 205 is connected in a rotationally fixed manner to the bell 113.

[0045] The first toothing 203a and the second toothing 203b of the intermediate gear 203 shown in Figure 2 have different pitch circle diameters. The pitch circle diameter of the first toothing 203 is smaller than the pitch circle diameter of the second toothing 203b. This gives the intermediate gear 203 a stepped shape. The first toothing 203a is designed as an external toothing, while the second toothing 203b is designed as an internal toothing.

[0046] In contrast, the intermediate gear 203 shown in Figure 3 has a cylindrical shape. The first gearing 203a and the second gearing 203b are designed as external gearings with the same pitch diameter.

[0047] The planetary gear 401 shown in Figure 4 differs from the planetary gears 201, 301, 501 shown in Figures 2, 3 and 5 with regard to the axial order of the toothings 103a, 103b, 103c, 105a, 105b of the first planetary gear 103 and the second planetary gear 105. The toothings 103a, 103b, 103c, 105a, 105b of the planetary gears 201, 301, 501 shown in Figures 2, 3 and 5 are arranged in the following axial order: Third toothing 103c of the first planetary gear 103, first toothing 103a of the first planetary gear 103, second toothing 103b of the first planetary gear 103, first toothing 105a of the second planetary gear 105 and second gearing 105b of the second planetary gear 105.In contrast, the gears 103a, 103b, 103c, 105a, 105b of the first planetary gear 103 and the second planetary gear 105 of the planetary gear 401 shown in Figure 4 are arranged in the following axial order: second gear 103b of the first planetary gear 103, first gear 105a of the second planetary gear 105, second gear 105b of the second planetary gear 105, third gear 103c of the first planetary gear 103, and first gear 103a of the first planetary gear 103. This has the advantage of a shorter connection of the second planet carrier 205 to the cage 113.

[0048] The planetary gear 501 shown in Figure 5 differs from the planetary gear 201 shown in Figure 2 with regard to the connection of the second planet carrier 205. The second planet carrier 205 according to Figure 5 is not connected to the cage 113, but extends toward the axially opposite side. This makes it possible to connect the second planet carrier 205 approximately rotationally fixed to the gear housing 109. It is also possible to fix the sun gear 117 rotationally fixed relative to the gear housing 109 and instead connect the second planet carrier 205 to a shaft for transmitting a torque flow. Furthermore, it is possible to design both the second planet carrier 205 and the sun gear 117 to be rotatable relative to the gear housing 109, so that the power transmitted by the planetary gear 501 is distributed to both components 205, 117. Reference numerals

[0049] Planetary gear Planet gear a Toothing b Toothing c Toothing Planet gear a Toothing b Toothing

[0050] Planet carrier gearbox housing ring gear

[0051] cage ring gear sun gear

[0052] Planetary gear intermediate gear a toothing b toothing planet carrier

[0053] Planetary gears Planetary gears Planetary gears

Claims

Patent claims 1. A gear arrangement (101, 201, 301, 401, 501) having a rotatable first planet carrier (107), a first planet gear (103) rotatably mounted in the first planet carrier (107), a second planet gear (105), a non-rotatable ring gear (109) meshing with a first toothing (103a) of the first planet gear (103), and a rotatable sun gear (117); characterized in that a second toothing (103b) of the first planet gear (103) is rotationally connected to the sun gear (117) via the second planet gear (105).

2. Gear arrangement (101, 201, 301, 401, 501) according to claim 1; characterized by a rotatable ring gear (111) which meshes with a third toothing (103c) of the first planetary gear (103), 3. Gear arrangement (101, 201, 301, 401, 501) according to one of the preceding claims; characterized in that the second toothing (105b) of the second planet gear (105) meshes with the sun gear (117).

4. Gear arrangement (101) according to one of the preceding claims; characterized in that the second toothing (103b) of the first planetary gear (103) meshes with the first toothing (105a) of the second planetary gear (105).

5. Gear arrangement (101) according to one of the preceding claims; characterized in that the second planet gear (105) is rotatably mounted in the first planet carrier (107).

6. Gear arrangement (201, 301, 401, 501) according to one of claims 1 to 3; characterized by a rotatable intermediate gear (203); wherein the second toothing (103b) of the first planetary gear (103) meshes with a first toothing (203a) of the intermediate gear (203); and wherein a second toothing (203b) of the intermediate gear (203) meshes with the first toothing (105a) of the second planetary gear (105).

7. Gear arrangement (201, 301, 401, 501) according to one of claims 1 to 3 or 6; characterized by a second planet carrier (205) rotatable relative to the first planet carrier (107), in which the second planet gear (105) is rotatably mounted.

8. Gear arrangement (201, 301, 401) according to the preceding claim; characterized in that the second planet carrier (205) is rotationally connected to the rotatable ring gear (111).

9. Gear arrangement (501) according to claim 7; characterized in that the second planet carrier (205) is rotatable relative to the rotatable ring gear (111), the sun gear (117) and the intermediate gear (203).

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