DE102012007623B4 - motor-gear unit - Google Patents

Abstract

Motor-gear unit (6) for an at least partially electric drive device (12), with 1.1 an electric machine (10), and 1.2 a planetary gear (11) connected to the electric machine (10), with a sun gear (16 ), with several planet gears (18) mounted on a revolving planet carrier (19) and with an outer ring (21) designed as a ring gear, wherein1.3 the sun gear (16) is firmly connected to a shaft (15) of the electrical machine (10). , whereby1.4 the planetary carrier (19) is firmly connected to an output shaft (7),1.5 a switching device (23) via which a first gear stage, a second gear stage or a neutral stage can be selected is provided, whereby1.6 via the Shifting device (23) in the first gear, the outer ring (21) is connected to a fixed component (25), wherein1.7 the outer ring (21) is connected to the planet carrier (19) via the switching device (23) in the second gear, and where1.8 above sea level The outer ring (21) is released via the switching device (23) in the neutral stage, with the planetary carrier (19) being mounted on the sun gear (16) and/or the shaft (15) of the electrical machine (10), characterized that1.10 the switching device (23) is designed as a claw circuit, wherein1.11 the electric machine (10) and the planetary gear (11) are arranged in a common housing (13), and wherein1.12 the electric machine (10) and the planetary gear (11) have a common oil circuit for lubrication and/or cooling.

Description

The invention relates to a motor-gear unit for an at least partially electric drive device according to the type defined in more detail in the preamble of claim 1. The invention also relates to a drive device with such a motor-gear unit. Ultimately, the invention also relates to a utility vehicle with such a drive device.

The combination of electrical machines with gears to form a motor-gear unit is known from the general state of the art. Such motor-transmission units can be provided in particular in at least partially electric drive devices, such as those used for hybrid vehicles or purely electrically powered vehicles. If there is sufficient installation space, the gear can be designed as a planetary gear. If there is less installation space, a simple, non-shiftable gear stage is typically provided.

As an example of such a motor-gear unit is on the DE 197 56 083 A1 be referenced, which shows structures with engine and generator and which describes the design as a motor-gear unit for these respective structures. Furthermore, from the U.S. 2009/0 247 346 A1 a manual transmission for a direct electric drive is known, which allows two gears and a neutral gear via a plate gear. Similar structures are also from the U.S. 1,598,586 A1 and the DE 10 2009 046 366 A1 known.

From the DE 10 2004 025 763 A1 in another context, the joint cooling and lubrication of hydraulic motors and the hydraulic pump supplying them with working medium is also known in a structure in which the hydraulic motors drive a gear.

For further general prior art can also on the WO 2011 / 098 594 A1 as well as the GB 1 294 548 A and the DE 10 2004 003 213 A1 to get expelled.

The U.S. 2005/0 211 490 A1 describes a vehicle drive device having a motor for driving wheels, an inverter for driving the motor, a rotational position sensor for detecting the rotation of the motor, a gear mechanism for transmitting a power of the motor to the wheels, an oil pump for circulating oil, and housing for motor , inverter, rotary position sensor, gearbox and oil pump. The motor, inverter, rotary position sensor transmission oil pump and housings are formed as an integral structure.

Furthermore, the DE 20 59 351 A a planetary gear with a large ratio jump. This can be used as a supplement to a main gear with fine gear grading.

Also describes the DE 198 10 592 A1 a motor vehicle starter/generator showing the features of the preamble of claim 1.

If such a motor-gear unit is to be implemented with the smallest possible space requirement, in particular with the smallest possible space requirement in its axial direction, then a single-stage gear must usually be used. This makes the structure of the electric machine correspondingly complex, since it must allow a very high speed spread in order to be able to provide the speed range typically required for the application with the single-stage gear of the motor-gear unit. This is correspondingly complex and expensive.

The object of the present invention is to specify a motor-gear unit which is extremely compact, particularly in the axial direction, and which can nevertheless cover a high speed range.

According to the invention, this object is achieved by the features in the characterizing part of claim 1. Advantageous developments of the solution according to the invention result from the dependent subclaims.

The motor-gear unit according to the invention comprises an electric machine and a planetary gear connected to the electric machine. According to the invention, a switching device is also provided, so that the planetary gear can be switched between a first gear, a second gear and a neutral gear. According to the invention, the sun gear of the planetary gear is firmly connected to the shaft of the electric machine and the planet carrier is firmly connected to an output shaft of the motor-gear unit. The switching device makes it possible to either connect the outer rim to a fixed component, i.e. to hold it in place relative to the other components of the planetary gear, to connect this outer rim to the planet carrier and thus to the output or the output shaft, or to release the outer rim entirely. This special design of the planetary gear with the three switching stages described can be implemented in an extremely compact manner and thus enables the motor-gear unit to be very short in the axial direction. In particular, this structure requires no more space than a simple non-shiftable transmission would also require.

If the outer rim is now held, the desired translation of the planetary gear is created. If it is connected to the output or the planetary carrier, the outer ring and the planetary carrier rotate together, resulting in a ratio of 1:1, i.e. a direct gear. If, on the other hand, the outer rim is released, no power transmission takes place, so that the transmission is in a neutral position. In the case of partially electric drive devices, in particular in the case of hybridized drive trains, this is advantageous in certain driving situations, since the electric machine can be decoupled as a result. All of this can be done directly within the motor-gear unit without an additional clutch, saving a great deal of installation space. In this case, the planetary carrier is mounted on the sun and/or the shaft of the electrical machine in order to obtain a compact structure in the axial direction.

In the motor-gear unit according to the invention, it is provided that the shifting device is designed as a claw shift. Such a claw circuit for connecting the outer ring either to a stationary component or to the planet carrier and in an intermediate position for “letting go” of the outer ring is particularly simple and efficient. It can be implemented in an extremely compact manner and also serves to make the motor-gear unit as compact as possible.

Furthermore, it is provided according to the invention that the motor-gear unit is designed in such a way that the electric machine and the planetary gear are arranged in a common housing. This also serves to make the motor-gear unit according to the invention as compact as possible.

In the motor-gear unit according to the invention, the electric machine and the planetary gear have a common oil circuit for lubrication and/or cooling. The components of the motor-transmission unit arranged in the common housing can be lubricated and/or cooled via a common oil circuit. A common oil circuit is particularly advantageous for lubrication. In terms of a very compact design, however, it is also provided that not only the lubrication but also the cooling is implemented via the one common oil circuit.

In a particularly advantageous development of the motor-gear unit according to the invention, it is provided that the planetary gear has a gear ratio of 1:2.5-3 in the first gear and a gear ratio of 1:1 in the second gear. The maximum speed of the electric machine is 1.5 - 2 times higher than the maximum output speed of the output shaft of the motor-gear unit. It has been shown that such an interpretation of the first gear to a gear ratio of 1: 2.5 - 3, preferably 1: 2.6 - 2.9, and the principle-related configuration of the second gear as a direct gear together with an electric machine , Which allows a higher maximum speed than the maximum required speed of the output shaft, an extremely compact design of the motor-gear unit according to the invention.

In a further very favorable embodiment of this, it is also provided that the dog clutch is designed without a mechanical synchronizing device. This omission of a mechanical synchronizing device allows the design to be made even simpler and more compact. Due to the direct connection of the sun to the electrical machine, the simple and very efficient claw circuit can be synchronized very easily and efficiently by accelerating or braking the electrical machine using the power electronics that control it. As a result, the additional cost and space required for a mechanical synchronizing device can be saved very easily.

According to an advantageous development, it can also be provided that the common housing is designed in two parts, the housing part surrounding the planetary gear being open in the direction of the electrical machine and being flanged to the housing part surrounding the electrical machine. This structure with a housing part open on one side around the planetary gear is extremely efficient in terms of assembly. The two housing parts can then, for example, be detachably flanged to one another via a screw connection and then form the common, very compact housing of the motor-gear unit according to the invention.

The motor-gear unit according to the invention preferably forms part of a drive device for an at least partially electrically driven vehicle, ie a hybrid vehicle or electric vehicle. The motor-gear unit according to the invention requires very little installation space in such a drive device according to the invention and allows the simple and efficient use of an electric machine, which can be designed in a correspondingly simple and efficient manner.

The preferred application of such a drive device is preferably in the field of commercial vehicles, which have an electric have a rule drive or a serial hybrid drive and in which area the drive device can be used particularly cheaply and efficiently. Such commercial vehicles can be buses, for example, which are used in local transport, as a result of which a particular potential for savings can be achieved, for example, by means of hybridization. In principle, however, it can also be used in parallel hybrids or in purely electrically powered vehicles.

Further advantageous refinements of the motor-gear unit according to the invention result from the remaining dependent claims and are clear from the exemplary embodiment, which is described in more detail below with reference to the figures.

• 1 eine Prinzipdarstellung eines Nutzfahrzeugs in einer möglichen Ausgestaltung gemäß der Erfindung; und
• 2 eine prinzipmäßige Schnittdarstellung durch die obere Hälfte einer erfindungsgemäßen Motor-Getriebe-Einheit.

The individual figures show:

• 1 a schematic representation of a commercial vehicle in a possible embodiment according to the invention; and
• 2 a basic sectional view through the upper half of a motor-gear unit according to the invention.

In the representation of 1 a vehicle 1, in particular a commercial vehicle, for example a bus, can be seen in a highly schematic manner. A drive device 2 is used to drive the vehicle 1, which is designed here as a so-called serial hybrid. This is to be understood purely as an example.

The drive device 2 includes an internal combustion engine 3, for example a diesel engine. This drives an electrical generator 4, which is connected to a motor-gear unit 6 via a power electronics unit 5, which can also have electrical energy stores. Wheels 9 of commercial vehicle 1 are then driven directly or, as shown here, via a differential 8 via an output shaft 7 of motor-gear unit 6 . The core of the drive device 2 of the commercial vehicle 1 shown here is the engine-transmission unit 6. This has, as already shown in FIG 1 is indicated in principle, an electric machine 10 and a gear 11 on. This gear 11 is designed as a planetary gear 11 .

In the sectional view of the 2 the upper half of the motor-transmission unit 6 is now indicated again in a sectional view in a highly schematic manner. The electrical machine 10, which can be operated both as a motor and, if necessary, also as a generator for the recuperation of braking energy, comprises a stator 12, which is arranged in a housing 13 in a rotationally fixed manner and surrounds a rotor 14. The rotor 14 rotates with a shaft 15. In the representation of 2 the planetary gear 11 with the output shaft 7 of the motor-gear unit 6 adjoins this shaft 15 in the axial direction on the right-hand side. A sun or a sun gear 16 of the planetary gear 11 is fixedly connected to the shaft 15 of the electric machine 10 and is mounted together with it via the bearings 17 indicated. A plurality of planet gears 18 , which are accommodated in a common planet carrier 19 , revolve around the sun gear 16 . In the exemplary embodiment shown here, the planet carrier 19 is also supported on the shaft 15 via a bearing 20 . Furthermore, an outer rim 21 is provided, which is designed in the usual way as a ring gear and which is supported via a bearing 22, for example on the planetary carrier 19.

The essential aspect of the planetary gear 11 shown here is that a shifting device 23 is also provided, which is preferably designed as a claw shift. The principle of the claw shift shown here has a shift claw 24 which, as indicated by the double arrow, can be displaced in the axial direction into two further positions relative to the position shown. The position of the shifting claw 24 shown here shows a neutral gear of the motor-transmission unit 6, in which the electric machine 10 is decoupled from the output shaft 7. The shifting claw 24 is in such a way that it only engages with the outer rim 21 . As a result, the outer rim 21 is loose and can move freely in the housing 13 . A power transmission between the sun 16 connected to the shaft 15 and the planetary carrier 19 connected to the output shaft 7 does not take place in this switching position.

If the shifting claw 24 with the shifting device 23 is now shifted to the right in the axial direction in the exemplary embodiment shown here, then it connects the outer rim 21 to a fixed component 25 which is arranged on the housing 13 in a rotationally fixed manner. The outer rim 21 is thus “held in place”. This results in a first gear of the motor-gear unit 6, which is determined by the ratio of the number of teeth of the outer rim 21 and the sun 16. In order to make the structure of the motor-gear unit 6 as compact as possible, this translation should preferably be on the order of 1:2.5-3, particularly preferably on the order of 1:2.6-2.9. The maximum speed of the electric machine 10 is then increased by a factor of 1.5-2 compared to the desired maximum speed of the output shaft 7 . This structure can be implemented in an extremely compact manner.

If the shift dog 24 is now from its neutral position in the other direction, ie in the axial direction in the representation of 2 shifted to the left, then it connects the outer rim 21 with the planetary carrier 19 or the output shaft 7 connected to the planetary carrier 19. Planetary carrier 19 and outer rim 21 thus form a mutually fixed unit, resulting in a ratio of 1: 1 in the planetary gear 11 as the second grade results.

The extraordinarily compact structure makes it possible to ideally meet the requirements of a motor-gear unit 6 in a hybridized or electrically configured drive train in a very simple and space-saving manner. The structure of the motor-gear unit 6 can be integrated in particular in the one housing 13 shown here, which in the illustrated embodiment consists of a first housing part 13.1 around the electric machine 10 and a second housing part 13.2 around the planetary gear 11. The housing part 13.2 can preferably be designed to be open in the direction of the other housing part 13.1, so that the planetary gear 11 can be assembled easily and efficiently. The two housing parts 13.1 and 13.2 are then connected to form the common housing 13, for example via indicated flanges which are connected via screws or the like. A welded connection of the housing parts 13.1 and 13.2 is also conceivable and possible in principle.

As already mentioned several times, the motor-gear unit 6 constructed in this way can be implemented in an extremely compact manner. This applies in particular when the electric machine 10 and the planetary gear 11 have a common oil circuit which is used both for lubricating and for cooling the electric machine 10 and the planetary gear 11 .

Claims (8)

Motor-gear unit (6) for an at least partially electric drive device (12), with 1.1 an electric machine (10), and 1.2 a planetary gear (11) connected to the electric machine (10), with a sun gear (16), with a plurality of planet wheels (18) mounted on a revolving planet carrier (19) and with an outer ring (21) designed as a ring gear, with 1.3 the sun wheel (16) being firmly connected to a shaft (15) of the electrical machine (10), with 1.4 the planet carrier (19) is firmly connected to an output shaft (7), 1.5 a switching device (23) is provided, via which a first gear stage, a second gear stage or a neutral stage can be shifted, 1.6 via the switching device (23) in the first gear the outer rim (21) is connected to a fixed component (25), wherein 1.7 the switching device (23) in the second gear the outer rim (21) is connected to the planetary carrier (19), and wob ei 1.8 the outer ring (21) is released via the switching device (23) in the neutral stage, with 1.9 the planetary carrier (19) being mounted on the sun gear (16) and/or the shaft (15) of the electrical machine (10), thereby characterized in that 1.10 the shifting device (23) is designed as a claw shift, 1.11 the electrical machine (10) and the planetary gear (11) being arranged in a common housing (13), and 1.12 the electrical machine (10) and the planetary gear (11) have a common oil circuit for lubrication and/or cooling. motor-gear unit (6). claim 1 , characterized in that the planetary gear (11) in the first gear has a translation of 1: 2.5 - 3 and in the second gear has a translation of 1: 1, the maximum speed of the electric machine (10) being 1 .5 - 2 times higher than the maximum speed of the output shaft (7). motor-gear unit (6). claim 1 or 2 , characterized in that the claw shift is designed without mechanical synchronizing devices. motor-gear unit (6). claim 1 , 2 or 3 , characterized in that the common housing (13) is designed in two parts, the housing part (13.2) surrounding the planetary gear (11) being open in the direction of the electrical machine (10) and being connected to the housing part (13.2) surrounding the electrical machine (10). 13.1) is flanged. Motor-gear unit (6) according to one of Claims 1 until 4 , characterized in that the sun wheel (16) is connected to the shaft (15) of the electrical machine (10) and is mounted together with it. Motor-gear unit (6) according to one of Claims 1 until 5 , characterized in that the outer ring (21) on the output shaft (7) and / or the planet carrier (19) is mounted. Drive device (12) for an at least partially electrically powered vehicle (1). a motor-gear unit (6) according to one of Claims 1 until 6 . Commercial vehicle (1), preferably a bus, with a drive device (12). claim 7 .

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