Planetary carrier of a planetary gearbox as well as planetary gearboxes with such a planetary carrier

Description

[0001] The present invention relates to a planetary carrier of a planetary gear. Furthermore, the invention relates to a planetary gear with such a planetary carrier.

[0002] Planetary gears are used in many applications where a high reduction or transmission ratio must be achieved in a small installation space. Planetary gears are characterized in particular by the fact that they have a planet carrier on which at least one planet gear, but usually three or four, are mounted. The planet gears mesh radially inward with a sun gear, while they mesh radially outward with a ring gear. While the planet carrier and sun gear are typically rotatable about a planet carrier axis of rotation, the planet gears are each mounted in the planet carrier so they can rotate about a planet gear axis of rotation.

[0003] Depending on the design of the planetary carrier, it has two spaced-apart carrier sections, each containing a first bearing bore and a second bearing bore for each planetary gear. The bearing bores have a closed perimeter. A receiving cavity in which the planetary gear can be arranged is located between the two carrier sections. The planetary gear often includes a planetary gear axle, which is inserted through the planetary gear and projects beyond the planetary gear on both sides. The projecting sections of the planetary gear axle engage in the two bearing bores. Such planetary carriers are known from DE 44 11 604 A1, EP 3 486 523 A1, US 2015 / 0330467 A1, DE 10 2009 026 751 A1, DE 10 2014 203 587 A1, US 2015 / 354672 A1, US 5 928 105 A and US 6 031 308 A.

[0004] The disadvantage of this is that, to assemble the planetary gear, the planetary gear must be aligned with the first bearing bore and the second bearing bore before the planetary gear axle can be pushed through the first bearing bore, the planetary gear, and the second bearing bore, with the planetary gear axle moving parallel to the planet carrier's rotational axis. Manufacturing the planetary gear is therefore difficult. Furthermore, it is not possible to manufacture the planetary gear axle integrally with the planetary gear.

[0005] The object of one embodiment of the present invention is to propose a planetary carrier for a planetary gear that is easy to manufacture and yet provides good meshing of the gears of the planetary gear. Furthermore, one embodiment of the present invention is based on the object of creating a planetary gear that can be operated with such a planetary carrier.

[0006] This object is achieved with the features specified in claims 1 and 5. Advantageous embodiments are the subject of the subclaims.

[0007] One embodiment of the invention relates to a planet carrier of a planetary gear, comprising a carrier body extending along a planet carrier rotation axis, a first carrier section connected to the carrier body, and a second carrier section connected to the carrier body, wherein the first carrier section and the second carrier section are arranged at a distance from one another along the planet carrier rotation axis and form at least one receiving cavity into which at least one planetary gear can be inserted, the at least one planetary gear having a first bearing section and a second bearing section with which the planetary gear can be rotatably mounted in the planet carrier about a planetary gear rotation axis, the first carrier section having a first bearing recess for each planetary gear and the second carrier section having a second bearing recess for each planetary gear, and the first bearing recess forming a first contact surface with which the first bearing section comes into contact with the first bearing section,when the planetary gear is arranged in the receiving cavity, the second bearing recess forms a second contact surface with which it comes into contact with the second bearing section, when the planetary gear is arranged in the receiving cavity, the first contact surface and / or the second contact surface are divided into a first contact surface section and a second contact surface section by a connecting line running through the planet carrier axis of rotation and the planetary gear axis of rotation, the first contact surface section encloses a first angle with the connecting line, the second contact surface section encloses a second angle with the connecting line, the first angle and the second angle lie in a plane that runs perpendicular to the planetary gear axis of rotation, and the first angle and the second angle are unequal and at least one of the angles is greater than 90°,

[0008] Due to the fact that bearing recesses are used instead of bearing bores as proposed, it is possible to insert the planet gear axle into the bearing recesses by means of a radial movement directed towards the planet carrier's axis of rotation. This makes it possible to pre-assemble the planet gear in question so that the planet gear axle can already be pushed through the planet gear before the planet gear axle is inserted into the bearing recesses. In particular, there is no longer any need to align the planet gear in alignment with the bearing bore. This significantly simplifies the production of the planetary gear. Due to the fact that at least one of the angles is greater than 90°, the contact surface is simultaneously enlarged to such an extent that radial outward migration of the planet gear axle is prevented.This ensures a favorable meshing of the planetary gear's gears. Because the first and second angles are different, the bearing recesses are designed asymmetrically. This allows at least one contact surface section to be designed so that it extends radially outward far around the planetary gear axis. The aforementioned radial drift of the planetary gears can thus be particularly effectively prevented.

[0009] According to a further embodiment, the first angle and the second angle of the first bearing recess are arranged in opposite directions to the first angle and the second angle of the second bearing recess with respect to the planet carrier's rotational axis. Depending on the direction of rotation of the planetary gear, a direction-dependent lateral force component can arise. Due to the opposite orientation, drift of the planet gears can be prevented regardless of the direction of rotation.

[0010] An embodiment not belonging to the present invention relates to a planet carrier of a planetary gear, comprising a carrier body extending along a planet carrier rotation axis, a first carrier section connected to the carrier body, and a second carrier section connected to the carrier body, wherein the first carrier section and the second carrier section are arranged at a distance from one another along the planet carrier rotation axis and form at least one receiving cavity into which at least one planetary gear can be inserted, the at least one planetary gear having a first bearing section and a second bearing section with which the planetary gear can be rotatably mounted in the planet carrier about a planetary gear rotation axis, the first carrier section having a first bearing recess for each planetary gear and the second carrier section having a second bearing recess for each planetary gear, and the first bearing recess forming a first contact surface with which the first bearing section comes into contact with the first bearing section,when the planetary gear is arranged in the receiving cavity, the second bearing recess forms a second contact surface with which it comes into contact with the second bearing section, when the planetary gear is arranged in the receiving cavity, the first contact surface and / or the second contact surface are divided into a first contact surface section and a second contact surface section by a connecting line running through the planet carrier axis of rotation and the planetary gear axis of rotation, the first contact surface section encloses a first angle with the connecting line, the second contact surface section encloses a second angle with the connecting line, the first angle and the second angle lie in a plane that is perpendicular to the planet carrier axis of rotation and the planetary gear axis of rotation, and the first angle and the second angle are equal to and greater than 90°.

[0011] Due to the proposed use of bearing recesses instead of bearing bores, it is possible to insert the planetary gear axle into the bearing recesses by means of a radial movement directed toward the planet carrier's rotation axis. This makes it possible to pre-assemble the planetary gear in question, allowing the planetary gear axle to be pushed through the planetary gear before the planetary gear axle is inserted into the bearing recesses. In particular, there is no need to align the planetary gear with the bearing bore. This significantly simplifies the production of the planetary gear.

[0012] Due to the fact that both angles are greater than 90°, the contact area is simultaneously enlarged to such an extent that radial outward migration of the planetary gears is prevented. This ensures favorable meshing of the planetary gear's gears.

[0013] According to a further embodiment or further development, the planet carrier consists of an injection-moldable plastic and is injection-molded. The use of injection molding makes it possible to produce a large number of planet carriers at low unit costs. Furthermore, the weight of the planet carrier can be kept low by using plastic. Due to the fact that plastic deforms more than steel under a given load and with a comparable planet carrier dimension, the aforementioned advantages of the asymmetric design of the bearing recesses become particularly apparent in plastic planet carriers.

[0014] In a further developed embodiment or further developed design, the planetary carrier is designed as a single piece. The single-piece design of the planetary carrier simplifies production because a joining step for connecting two or more parts of the planetary carrier is eliminated. Furthermore, warehousing is simplified because only the planetary carrier itself needs to be kept in stock, eliminating the need to ensure that multiple parts are available.

[0015] One embodiment of the invention relates to a planetary gear comprising a planet carrier according to one of the previous embodiments or configurations, and at least one planet gear which is mounted on the planet carrier so as to be rotatable about a planet gear rotation axis.

[0016] The technical effects and advantages that can be achieved with the proposed planetary gear system correspond to those discussed for the planet carrier. In summary, it should be noted that the production of the planetary gear system can be simplified, in particular, by pre-assembling the planet gears and the planet gear axles and assembling them by means of a radial movement directed toward the planet carrier's rotational axis.

[0017] According to another design, the planetary gear has helical planetary gear teeth. Helical planetary gears are subject to particular stresses. While virtually no forces act along the planet carrier's rotational axis on a spur-toothed planetary gear, axial and radial forces overlap in helical planetary gears. Particularly when the planet carrier or the entire planetary gear is made of plastic, the radial and axial forces cause increased deformation, particularly of the planet carrier, which can lead to radial drift of the planetary gears. This disrupts the optimal meshing of the planetary gear's gears.Due to the proposed design of the bearing recesses of the planet carrier, radial migration of the planetary gears is prevented or at least reduced to such an extent that the engagement of the gears of the planetary gear is not negatively affected.

[0018] According to a further development, the planetary gear's rotational axis is skewed relative to the planetary carrier's rotational axis. In this configuration, the planetary gear is designed as a helical planetary gear. Helical planetary gears enable even higher transmission or reduction ratios to be achieved in the same space compared to straight-toothed or helical-toothed planetary gears.

[0019] Another design is characterized by the fact that the first bearing section and the second bearing section are formed integrally with the planetary gear. In known planetary gears, the bearing sections are formed by a planetary gear axle that extends through the planetary gear. The planetary gear axle therefore forms an additional component, which can be eliminated in this design, thus simplifying assembly and storage.

[0020] Exemplary embodiments of the invention are explained in more detail below with reference to the accompanying drawings. Figure 1A shows a planet carrier according to the state of the art in a perspective view, Figure 1B shows the Figure 1A shown planet carrier based on a front view, Figure 1C a planetary gear which is mounted on the planet carrier according to the Figures 1A and 1Bcan be rotatably mounted, Figure 2A shows a first embodiment of a planet carrier not according to the invention in a perspective view, Figure 2B which in Figure 2B shown first embodiment of the planet carrier based on a front view, Figure 3A a second embodiment of a planet carrier according to the invention based on a perspective view, Figure 3B the Figure 3A shown second embodiment of the planet carrier based on a front view, Figures 4A to 4C a third embodiment of a planet carrier according to the invention based on various representations, Figure 4D the Figures 4A to 4Cillustrated planet carrier with a planet gear mounted on it based on a partial representation, Figure 4E a basic representation of a planet gear which can be mounted on an embodiment of the planet carrier according to the invention, and Figure 5 a basic representation of a planetary gear.

[0021] In the Figures 1A and 1BA planet carrier 10 according to the prior art is shown in a perspective view and a front view. The planet carrier 10 has a carrier body 12, to which a first carrier section 14 and a second carrier section 16 are fastened at a distance from one another with respect to a planet carrier rotation axis APT. During operation, the planet carrier 10 is rotatable about the planet carrier rotation axis APT. Both the first carrier section 14 and the second carrier section 16 are approximately disc-shaped and connected by webs 18. Between the first carrier section 14 and the second carrier section 16 and between the webs 18, the planet carrier 10 forms a total of three receiving cavities 20, into each of which a planet gear 22 (see Figure 1C ) can be introduced.

[0022] The first carrier section 14 has three first bearing bores 24, and the second carrier section 16 has three second bearing bores 26, each of which serves to support a planetary gear 22. The first bearing bores 24 are aligned along the planetary carrier rotation axis APT in alignment with the second bearing bores 26.

[0023] As mentioned, in Figure 1C a planetary gear 22 is shown, which is mounted on the Figures 1A and 1B shown planet carrier 10. The planet gear 22 comprises a planet gear axle 28, which can be designed as a pin, for example made of metal, which can be pushed through a corresponding through hole 30 of the planet gear 22. As can be seen from the Figure 1C As can be seen, the planetary gear axle 28 projects axially beyond the planetary gear 22 on both sides. The projecting sections form a first bearing section 32 and a second bearing section 34.

[0024] As can be seen from the Figures 1A and 1B As can be seen, the bearing bores 24, 26 are completely closed. In order to Figure 1CIn order to be able to mount the planetary gear 22 shown on the planet carrier 10, the planetary gear 22 must be introduced into the receiving cavity 20 without the planetary gear axle 28 in such a way that the through-bore 30 of the planetary gear 22 is aligned with one of the first bearing bores 24 of the first carrier section 14 and one of the second bearing bores 26 of the second carrier section 16. The planetary gear axle 28 is then passed first through the first bearing bore 24, then through the through-bore 30 of the planetary gear 22 and finally through the second bearing bore 26. In the assembled state, the first bearing section 32 engages in the first bearing bore 24 and the second bearing section 34 engages in the second bearing bore 26. Furthermore, the assembled planetary gear 22 is mounted in the planetary carrier 10 so as to be rotatable about a planetary gear rotation axis APR, which runs parallel to the planetary carrier rotation axis APT.

[0025] From this it can be seen that the assembly required to mount the planetary gear 22 on the planetary carrier 10 is comparatively complex.

[0026] In the Figures 2A and 2B A first exemplary embodiment of a planetary carrier 36 1 not according to the invention is shown in a perspective view and a front view. The basic structure of the planetary carrier 36 1 according to the first exemplary embodiment corresponds to that of the planetary carrier 10 shown in the Figures 1A and 1B shown and described. Therefore, only the essential differences will be discussed. In contrast to the planet carrier 10 known from the prior art according to the Figures 1A and 1BAccording to the first exemplary embodiment, the planet carrier 36 1 does not have bearing bores 24, 26, but rather bearing recesses 38, 40. Specifically, the first carrier section 14 comprises three first bearing recesses 38, and the second carrier section 16 comprises three second bearing recesses 40, which are aligned along the planet gear rotation axis APR. As mentioned, the bearing bores 24, 26 are completely closed along the circumference, while the first bearing recess 38 and the second bearing recess 40 are open radially outward.

[0027] As can be seen in particular from the Figure 2BAs can be seen, the first bearing recess 38 forms a first contact surface 42, with which the first bearing recess 38 comes into contact with the first bearing section 32 of the planetary gear 22 in the assembled state. Accordingly, the second bearing recess 40 forms a second contact surface 44, with which the second bearing recess 40 comes into contact with the second bearing section 34 of the planetary gear 22 in the assembled state.

[0028] In Figure 2B It can also be seen that in the assembled state, the planet gear 22 is mounted in the planet carrier 36 1 and in particular in the first bearing recess 38 so that it can rotate about the planet gear rotation axis APR. In the first embodiment of the planet carrier 36 1, the planet gear rotation axis APR runs parallel to the planet carrier rotation axis APT. Furthermore, in the Figure 2Ba connecting line G is shown, which runs through the planet carrier rotation axis APT and the planet gear rotation axis APR. The connecting line G divides the first contact surface 42 into a first contact surface section 46 and a second contact surface section 48.

[0029] Due to the fact that the first bearing recess 38 is open radially outwards, the first contact surface section 46 and the second contact surface section 48 do not completely enclose the first bearing section 32, but only with a first angle α and a second angle β, respectively, which the first contact surface section 46 and the second contact surface section 48 enclose with the connecting line G. According to the first exemplary embodiment of the planet carrier 36 1, the first angle α and the second angle β are, on the one hand, the same size and, on the other hand, greater than 90° and less than 180°. Due to the fact that the first angle α and the second angle β are each greater than 90°, an undercut is created which fixes the first bearing section 32 radially outwards. Migration of the first bearing section 32 during operation of the planet carrier 36 1 is hereby prevented.

[0030] In the first embodiment of the planet carrier 36 1, the second bearing recess 40 is constructed in the same way as the first bearing recess 38 and therefore has the same properties.

[0031] Furthermore, the planet carrier 36 1 is designed as a single piece and is made of an injection-moldable plastic.

[0032] In the Figures 3A and 3B A second embodiment of a planetary carrier 36 2 according to the invention is shown in a perspective view and a front view, respectively. The essential structure of the planetary carrier 36 2 according to the second embodiment corresponds to the structure of the planetary carrier 36 1 according to the first embodiment. However, the first bearing recess 38 and the second bearing recess 40 are constructed differently.

[0033] In Figure 3BThe first bearing recess 38 according to the second embodiment of the planet carrier 36 2 according to the invention is clearly visible. In contrast to the first embodiment of the planet carrier 36 1 according to the invention, the first angle α is not equal to the second angle β, but they differ. As can be seen from the Figure 3B As can be seen, the first angle α is greater than the second angle β. Both the first angle α and the second angle β are greater than 90° and less than 180°.

[0034] As can be seen in particular from the Figure 3A As can be seen, the first angle α and the second angle β in the first bearing recess 38 relative to the planetary gear rotation axis APR run in the opposite direction to the first angle α and the second angle β of the second bearing recess 40. In other words, the first bearing recesses 38 are relative to the Figures 3A and 3Bselected representation is open to the left, while the second bearing recesses 40 are open to the right.

[0035] In the Figures 4A to Figure 4C A third embodiment of the planet carrier 36 3 according to the invention is shown in various representations. The planet carrier 36 3 according to the third embodiment largely corresponds to the planet carrier 36 2 according to the second embodiment. However, as can be seen from the Figure 4D which shows an enlarged section of the Figures 4A to 4C As shown in Figure 3, the second angle β is less than 90°, while the first angle α is significantly more than 90°, but less than 180°.

[0036] In the Figure 4E a planetary gear 49 is shown, which can be used with the illustrated embodiments of the planetary carrier 36. In contrast to the Figure 1CIn the planetary gear 22 shown, the first bearing section 32 and the second bearing section 34 are formed integrally with the planetary gear 49. Consequently, the planetary gear 49 is designed as a single piece, so that a separate planetary gear axle 28 does not have to be provided. Nevertheless, the Figure 1C The planetary gear 22 shown can also be used with all illustrated embodiments of the planetary carrier 36 2 - 36 3 according to the invention. It should be noted that the Figure 4E The planetary gear 49 shown has a helical planetary gear toothing 50.

[0037] To assemble the planet carrier 36, for example, the Figure 4EThe planetary gear 49 shown is introduced into the first bearing recess 38 and the second bearing recess 40 by means of a movement directed towards the planetary carrier rotation axis APT. To assemble the planetary carrier 36 2 , 36 3 according to the second and third embodiments, the planetary gear 22 must be rotated slightly about the connecting line G, so that a helical or screw-shaped movement must be carried out. In both cases, however, the assembly is more complex than the assembly of the planetary gear shown in the Figures 1A and 1B illustrated planet carrier 10 according to the prior art is significantly simpler, in particular because the aligned alignment of the planet gear 22 with respect to the first bearing bore 24 and the second bearing bore 26 can be omitted.

[0038] In Figure 5A planetary gear 52 is shown in a schematic diagram, in which a total of three planet gears 49 are mounted by means of a planet carrier 36 according to one of the previously described embodiments. In addition to the planet gears 49, a central sun gear 54 and a ring gear 56 can be seen. The planet gears 49 are in meshing engagement with both the sun gear 54 and the ring gear 56.

[0039] The ring gear 56 is not rotatable, while the sun gear 54 can rotate about a sun gear rotation axis ASR, which coincides with the planet carrier rotation axis APT. The planet gears 49 are each mounted in the planet carrier 36 so they can rotate about a planet gear rotation axis APR. The planet gear rotation axes APR run parallel to the planet carrier rotation axis APT.

[0040] The planetary gear 52 is made entirely of an injection-moldable plastic.

[0041] Not shown is an embodiment in which the planetary gear rotation axes APR are skewed relative to the planet carrier rotation axis APT. In this embodiment, the planetary gear 52 is designed as a helical planetary gear. List of reference symbols

[0042] 10Planet carrier according to the state of the art 12Carrier body 14First carrier section 16Second carrier section 18Web 20Holding cavity 22Planet gear 24First bearing bore 26Second bearing bore 28Planet gear axle 30Through hole 32First bearing section 34Second bearing section 36Planet carrier 36 1 - 36 3 Planet carrier 38First bearing recess 40Second bearing recess 42First contact surface 44Second contact surface 46First contact surface section 48Second contact surface section 49Planet gear 50 Helical planetary gear teeth 49 Planetary gear 52 Planetary gear 54 Sun gear 56 Ring gear APT Planetary carrier rotation axis APR Planetary gear rotation axis G Connecting line α First angle β Second angle

Claims

1. A planet carrier (36) of a planetary gearbox (52), comprising - a carrier body (12) extending along a planet carrier rotation axis (APT), - a first carrier portion (14) connected to the carrier body (12), and - a second carrier portion (16) connected to the carrier body (12), wherein - the first carrier portion (14) and the second carrier portion (16) are arranged at a distance from one another along the planet carrier rotation axis (APT) and form at least one receiving cavity (20) into which at least one planet gear (22, 49) can be introduced, - the at least one planetary gear (22, 49) has a first bearing portion (32) and a second bearing portion (34), with which the planetary gear (22, 49) can be mounted in the planetary carrier (36) so as to be rotatable about a planetary gear rotation axis (APR), - the first carrier portion (14) has a first bearing recess (38) for each planetary gear (22, 49) and the second carrier portion (16) has a second bearing recess (40) for each planetary gear (22, 49), and - the first bearing recess (40) forms a first contact surface (42) with which it comes into contact with the first bearing portion (32) when the planetary gear (22, 49) is arranged in the receiving cavity (20), - the second bearing recess (38) forms a second contact surface (44) with which it comes into contact with the second bearing portion (34) when the planetary gear (22, 49) is arranged in the receiving cavity (20), - the first contact surface (42) and / or the second contact surface (44) are divided into a first contact surface portion (46) and a second contact surface portion (48) by a connecting straight line (G) passing through the planet carrier rotation axis (APT) and the planet gear rotation axis (APR), - the first contact surface portion (46) encloses a first angle (α) with the connecting straight line (G), - the second contact surface portion (48) encloses a second angle (β) with the connecting straight line (G), - the first angle (α) and the second angle (β) lie in a plane perpendicular to the planet carrier axis of rotation (APT), characterized in that - the first angle (α) and the second angle (β) are unequal and at least one of the angles (α, β) is greater than 90°.

2. The planet carrier (36) according to claim 1, characterized in that the first angle (α) and the second angle (β) of the first bearing recess (38) are arranged in relation to the planet carrier axis of rotation (APT) in opposite directions to the first angle (α) and the second angle (β) of the second bearing recess (40).

3. The planet carrier (36) according to any one of the preceding claims, characterized in that the planet carrier (36) consists of an injection-moldable plastic and is injection-molded.

4. The planet carrier (36) according to any one of the preceding claims, characterized in that the planet carrier (36) is designed in one piece.

5. A planetary gearbox (52), comprising - a planet carrier (36) according to any one of the preceding claims, and - at least one planetary gear (22, 49) which is mounted on the planetary carrier (36) so as to be rotatable about a planetary gear rotation axis (APR).

6. The planetary gearbox (52) according to claim 5, characterized in that the planetary gear (22, 49) has a helical planetary gear toothing (50).

7. The planetary gearbox (52) according to claim 5, characterized in that the planet gear rotation axis (APR) is skewed relative to the planet carrier rotation axis (APT).

8. The planetary gearbox (52) according to any one of claims 5 to 7, characterized in that the first bearing portion (32) and the second bearing portion (34) are formed integrally with the planetary gear (49).