DE102013220835A1 - Planetary gear, in particular axle for a motor vehicle - Google Patents

Abstract

The invention relates to a planetary gear for branching the voltage applied to a power input drive power to a first and a second power output in conjunction with a reduction of the output speed to a below the input speed at the power input speed level, with a superposition gear, the first sun gear, a first Planet set, a first planetary carrier and a first ring gear includes, and a reverse gear stage comprising a second sun gear, a second planetary gear set, a second planet carrier and a second ring gear, wherein the first sun gear acts as a power input, the first ring gear is rotatably coupled to the second ring gear in that the first power output is accomplished via the first planet carrier of the superposition gear stage, the second power output is accomplished via the reverse gear stage, in which the second sun gear constitutes the second power output, the second planetary gear set is formed as a double planetary gearset having at least a pair of intermeshing double planets, wherein one planet of this double planetary gear pair is engaged with the second sun gear and the second ring gear and the other planet of this double planetary gear pair is engaged with a stationary ring gear ,

Description

Field of the invention

The invention is directed to a planetary gear, in particular in the configuration of a transaxle for dividing the provided by a drive device and supplied via a power input drive power to a first and a second power output, wherein within the Umlaufrädergetriebes a translation takes place, so that the power tap on the two Power outputs on a relative to the input speed at the power input reduced output speed level takes place.

Out US 5,845,732 A is a planetary gear transmission of the aforementioned type known. The power split within the transmission is here effected by a superposition gear stage comprising a sun gear, a planet carrier equipped with planets, and a ring gear. The drive power provided by an engine is introduced via the extent acting as a power input sun gear in the transmission, the power split takes place on the planet carrier and the ring gear. The planet carrier is in this case coupled to a first output shaft. The ring gear is coupled to the sun gear of the second planetary stage. The reversing gear stage comprises a stationary ring gear and a planet carrier equipped with double planets. This planet carrier is coupled to a second output shaft.

Object of the invention

The invention has for its object to provide a planetary gear, in particular in the form of a transaxle, which is characterized by a cost feasible, robust and baren in terms of its mechanical performance, robust and advantageous in terms of its mechanical performance structure.

Inventive solution

• – einer Überlagerungsgetriebestufe die ein erstes Sonnenrad, einen ersten Planetensatz, einen ersten Planetenträger und ein erstes Hohlrad umfasst, und
• – einer Wendegetriebestufe die ein zweites Sonnenrad, einen zweiten Planetensatz, einen zweiten Planetenträger und ein zweites Hohlrad umfasst,

wobei

• – das erste Sonnenrad als Leistungseingang fungiert,
• – das erste Hohlrad mit dem zweiten Hohlrad drehfest gekoppelt ist,
• – der erste Leistungsausgang über den ersten Planetenträger der Überlagerungsgetriebestufe bewerkstellig ist,
• – der zweite Leistungsausgang über die Wendegetriebestufe bewerkstelligt ist, indem das zweite Sonnenrad den zweiten Leistungsausgang darstellt,
• – der zweite Planetensatz als Doppelplanetensatz ausgebildet ist, der wenigstens ein Paar miteinander in Eingriff stehende Doppelplaneten aufweist, wobei jeweils ein Planet dieses Doppelplanetenpaares mit dem zweiten Sonnenrad, sowie dem zweiten Hohlrad in Eingriff steht und der weitere Planet dieses Doppelplanetenpaares mit einem stationären Hohlrad in Eingriff steht.

The above-mentioned object is achieved by a planetary gear for branching the voltage applied to a power input drive power to a first and to a second power output on a relative to the drive speed lowered speed level, with:

• - A superposition gear stage comprising a first sun gear, a first planetary gear set, a first planetary carrier and a first ring gear, and
• A reversing gear stage comprising a second sun gear, a second planetary gear set, a second planet carrier and a second ring gear,

in which

• - the first sun gear acts as a power input,
• - The first ring gear is rotatably coupled to the second ring gear,
• The first power output via the first planet carrier of the superposition gear stage is accomplished,
• The second power output is accomplished via the reverse gear stage, the second sun gear representing the second power output,
• - The second planetary gear set is designed as a double planetary set having at least one pair of mutually engaging double planet, each one planet of this double planetary pair with the second sun gear and the second ring gear is engaged and the other planet of this double planetary pair with a stationary ring gear into engagement stands.

This makes it possible in an advantageous manner to provide an axle or intermediate differential, which offers a required, in particular symmetrical power split and a high mechanical system efficiency.

The invention relates in essence to a differential in the design as mutually coupled, rolling planetary gear (so-called. Rolling differential). The transmission unit according to the invention represents a combination of differential and final drive ratio stage. The differential can be used in the area of the final drive if an additional ratio is required without reversing the direction of rotation. The invention provides a rolling differential with positive final drive ratio, wherein the partial transmissions have relatively simple structures.

In this case, the second sun gear may advantageously be designed such that the axial length of the external toothing of this spur gear at least corresponds to the distance over which the inner toothings of the two ring gears of the reverse gear stage extend in the direction of the transmission axis. The axial length of the second planetary gear set meshing with that second sun gear preferably corresponds to the axial length of the spur gear toothing of the second sun gear. The axial length of the spur gear teeth of the stationary ring gear engaged planet of the respective double planetary pair preferably corresponds to the axial length of the internal teeth of that stationary ring gear.

The respective double planetary pair is preferably designed and arranged such that the teeth of the planets of the second planetary gearset engaging in the stationary ring gear project radially beyond those enveloping circles which are concentric with the transmission axis and surround the head circles of the planets engaging in the second ring gear. The two planets of a double planetary pair are in this case mounted such that the axes have different radial distances from the transmission axis, ie to the axis of rotation of the second planetary carrier. In particular, the axial spacing of the planet engaging in the stationary ring gear is dimensioned such that these planets do not engage in the sun gear of the reverse gear stage.

The gears of the transmission according to the invention are preferably designed as helical spur gears. The first ring gear and the second ring gear can be formed by a continuously internally toothed ring element and thus constitute sections of an integral part. The second sun gear and the first planet carrier can be radially and optionally axially supported by a bearing arrangement. The first and the second ring gear can be mounted in the transmission housing via a bearing device. This gear housing be stored on a bearing device. This bearing device can optionally sit in a ring section of the third ring gear. In addition, or alternatively to the aforementioned measure, the first ring gear can also be mounted on the first planet carrier or the drive shaft of the first sun gear. Overall, numerous circulating components can be radially supported against one another by bearing arrangements, preferably designed as roller bearings, in order thereby to ensure forcibly or statically overdetermined ideal engagement conditions and component positioning.

According to a particularly preferred embodiment of the invention, the epicyclic gear is designed such that the drive of the first Sonnerades via a hollow shaft journal through which an attached to the first line output first output shaft is passed coaxially. The first sun gear can in this case be mounted on the first output shaft via a bearing arrangement, in particular a rolling bearing arrangement.

The power supply to the first sun gear preferably takes place via an axially offset from the first sun gear, and the same axis to the first sun drive wheel which is designed as a sprocket, bevel or spur gear or as a running disk of a traction drive. This drive wheel is preferably formed either integrally with the first sun gear, or coupled thereto via said hollow shaft journal or drive shaft stub.

The second power output preferably comprises a second output shaft which is rotatably connected to the second sun gear. The second ring gear is preferably mounted on a rolling bearing assembly in the transmission housing.

The superposition gear stage functions as a true epicyclic gearing that accomplishes power splitting to the first sun gear and to the first ring gear. The reversing gear stage causes not only a change in the direction of rotation but also a translation "into the slow".

The invention relates to a rolling differential with positive total ratio, e.g. can be used for electric axle drives. It has a standard planetary gearset as a superposition gearbox, as well as a reduced coupling set as a gearbox with a common ring gear. The invention relates to a differential in the design as mutually coupled, rolling planetary gear (so-called. Rolling differential). The unit is a combination of differential and final drive ratio stage. The differential can be used in the final drive area if an additional ratio is required without reversing the direction of rotation. In particular, in this invention, the reversing gear is formed by a so-called "reduced coupling set". This special design has three central wheels (one sun and two ring gears) and only one planet carrier and two intermeshing planets. The planet gears are simple and not tiered. A ring gear of the coupling set is held, the other ring gear serves as a power input, the sun as a power output. The planetary carrier of the reverse gear stage is not connected and runs freely around, i. he does not carry any external torque.

Brief description of the figures

Further details and features of the invention will become apparent from the following description taken in conjunction with the drawings. It shows:

1 a schematic representation of a first embodiment of a running as axle differential gear according to the invention Umlaufrädergetriebes, to illustrate the basic structure of this transmission, as well as the operative linkage of the transmission components.

Detailed description of the figures

The representation after 1 shows in the form of a schematic representation of a first embodiment of a planetary gear according to the invention which is designed here as axle drive for a motor vehicle. This planetary gear transmission according to the invention serves to branch at one Power input I applied drive power to a first and to a second power output O1, O2. The epicyclic gearing comprises a superposition gearing stage G1 which comprises a first sun gear S1, a first planetary gear set P1, a first planet carrier C1 and a first ring gear H1.

The epicyclic gearbox also includes a reverse gear stage G2 which has a second sun gear S2, a second planetary gear set P2, a second planet carrier C2 and a second ring gear H2. The second planetary gear set P2 is designed as a double planetary gearset and comprises at least one pair of engaged double planets P2a, P2b, wherein one planet P2a of a double planetary gear pair is engaged with the second sun gear S2 and the second ring gear H2, and the other planet P2b of this double planetary pair with a stationary ring gear H3 is engaged. The stationary fixing of the ring gear H3 is done by this is coupled torsionally rigid with the transmission housing G.

Furthermore, the first sun gear S1 acts as a power input. The first ring gear H1 is rotatably coupled to the second ring gear H2. The first power output O1 is accomplished via the first planet carrier C1 of the superposition gear stage G1. The second power output O2 is accomplished via the reverse gear stage G2 by the second sun gear S2 driving the second power output.

The first power output O1 comprises a first output shaft OS1, which is passed coaxially through the first sun gear S1. The second power output O2 comprises a second output shaft OS2 which is non-rotatably connected to the second sun gear S2.

The planetary gear shown here is designed as a final drive for a motor vehicle. The two output shafts OS1, OS2 lead to a left or a right drive wheel of a vehicle axle. The planetary gear can be used in particular as a transfer case in a motor vehicle, for dividing the drive power to a front and a rear vehicle axle. In the latter case, the transmission system, if required, also realize an asymmetrical torque distribution.

The drive of the first sun gear S1 via a hollow shaft journal 4 , This hollow shaft journal 4 is via an input gear 5 driven. The entrance wheel 5 is designed here as a sprocket and is driven by a drive chain as such produces a kinematic connection between the epicyclic gear shown here and a not shown in detail, upstream gearbox, in particular an automatic or manual transmission, or possibly also an electromechanical drive.

The first sun gear S1 engages in the planets of the first planetary set P1. These first planets are mounted on the first planet carrier C1. The first planet carrier C1 is rotatably coupled to the output shaft OS1. The first planets P1 roll in the first ring gear H1. The first ring gear H1 is rotatably coupled to the second ring gear H2 of the reverse gear stage G2.

The second sun gear S2 engages in the second planet P2a of the double planetary gear set P2 of the reverse gear stage G2. These second planets P2a are mounted in the second planet carrier C2. This planet carrier C2 is rotatably mounted relative to the transmission housing G. The second planet P2a engage from inside into the second ring gear H2. This second ring gear H2 is rotatably mounted in the gear housing G and, as already mentioned, rotatably coupled to the first ring gear H1.

The superposition gear stage G1 functions as a branching gear and constitutes a true epicyclic gearing. The gearing stage G2 compensates the branching effect of the first gear stage G2, which is unequal in terms of the output torques.

The planetary gear transmission according to the invention is particularly suitable as a final drive for cars with positive final drive ratio. The invention relates in essence to a differential in the design as coupled together. rolling planetary gear (so-called rolling differential) The unit represents a combination of be (so-called rolling differential) The unit represents a combination of differential and final drive ratio stage. The differential can be used in the area of the final drive, if an additional translation is required.

The transmission according to the invention is particularly suitable for use in vehicles with electric drives, in particular drives with rotating field motors in which the drive torque applied to the first gear G1 is provided by a relatively high-torque rotor at a relatively low torque. That electric motor can be arranged coaxially to the axis of rotation of the first sun gear S1, or also radially offset to this.

The superposition gear G1 of the rolling differential is used for power division. The drive power of the sun gear S1 is divided equally between the planet carrier C1 and the ring gear H1. Since the ring gear H1 and the planet carrier C1 of the superposition gear G1 indeed same performance, but different torques lead, it requires a further reversing gear G2 to ultimately produce equal torques on the output shafts. The state ratios of the two planetary gears G1, G2 are therefore interdependent. The coupling of the two gears G1, G2 is in this case selected so that there is a positive axle ratio. As shown, for example, a total ratio of +10 or +8 can be achieved by selecting appropriate stand ratios.

In particular, in this invention, the reversing gear G2 is formed by a so-called "reduced coupling set". This particular design has three central wheels coaxial with the transmission axis (one sun S2 and two ring gears H2, H3) and only one planet carrier C2, as well as at least two planetary gears P2a, P2b which are paired and meshed with each other. The planet gears P2a, P2b are simple and not stepped. A ring gear H3 of the coupling set is held, the other ring gear H2 serves as a power input of this stage G2 and the sun gear S2 as a power output. The planet carrier C2 is not connected and is running "freely", i. he does not carry any external torque. With this design, it is possible using simple gear parts to produce a negative partial ratio slower, i. the sun S2 carries a higher torque than the input-side ring gear H2. Furthermore, the common ring gear H1 / H2 of superposition and reverse gear can be designed with identical teeth

The reversing gear is designed as a so-called. Reduced coupling set, the first ring gear H1 and the second ring gear H2 are formed by a common component parts G1, G2, the planets P2a, P2b of the second planetary gear set are ungestufted.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5845732 A [0002]

Claims (10)

 Epicyclic gearing for branching the drive power present at a power input (I) to a first and to a second power output (O1, O2) at a speed level lowered relative to the input rotational speed, comprising: - A superposition gear stage (G1) comprising a first sun gear (S1), a first planetary gear set (P1), a first planet carrier (C1) and a first ring gear (H1), and A reversing gear stage (G2) comprising a second sun gear (S2), a second planetary gear set (P2), a second planet carrier (C2) and a second ring gear (H2), in which The first sun gear (S1) acts as a power input, - the first ring gear (H1) is rotatably coupled to the second ring gear (H2), - The first power output (O1) via the first planet carrier (C1) of the superposition gear stage (G1) is accomplished, - the second power output (O2) is accomplished via the reverse gear stage (G2) by the second sun gear (S2) driving the second power output, - The second planetary gear set (P2) is designed as a double planetary set having at least a pair of mutually engaged double planets (P2a, P2b), wherein in each case a planet (P2a) of this double planetary pair with the second sun gear (S2), and the second ring gear ( H1) is engaged and the further planet (P2b) of this double planetary pair with a stationary ring gear (H3) is engaged. Planetary gear according to claim 1, characterized in that the first power output (O1) comprises an output shaft (OS1), which is guided coaxially through the first sun gear (1). Planetary gear according to claim 1 or 2, characterized in that the output shaft (OS1) in the first sun gear (S1) is mounted. Planetary gear according to at least one of claims 1 to 3, characterized in that the second power output (O2) comprises an output shaft (OS2) which is non-rotatably connected to the second sun gear (S2). Planetary gear according to at least one of claims 1 to 4, characterized in that in the third ring gear (H3) engaging planet (P2b) of the double planetary gear set (P2) on the second planet carrier (C2) are mounted on an axle circle whose diameter is larger than that Diameter of the axis circle on which in the second sun gear (S2) engaging planet (P2a) of the double planetary gear set (P2) are arranged. Planetary gear according to at least one of claims 1 to 5, characterized in that the first ring gear (H1) and the second ring gear (H2) are formed by an integral part. Planetary gear according to at least one of claims 1 to 6, characterized in that the first output shaft (OS1) and the second output shaft (OS2) are centered against each other. Planetary gear according to claim 7, characterized in that the second sun gear (S2) of the reverse gear stage (G2) is designed such that its measured in the direction of the transmission axis (X) length of the external teeth at least the sum of the also in the direction of the transmission axis (X) measured Length of the internal teeth of the two ring gears (H2, H3) corresponds to the reversing gear stage (G2). Planetary gear according to at least one of claims 1 to 8, characterized in that the first ring gear (H1) is mounted on the first planet carrier (C1). Planetary gear according to at least one of claims 1 to 9, characterized in that this transmission is part of an electric drive with a to the transmission axis (X) coaxial, or radially offset to this rotary field motor forms.

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