Gear arrangement for a hybrid drive with winding gears

Abstract

Transmission arrangement for a hybrid drive, with a first transmission (16) which is designed as a dual-clutch transmission and is intended to be coupled to a first drive machine, an internal combustion engine (10), and a second transmission (18) which is intended to be coupled to a second drive machine, wherein the first and the second transmission (16, 18) can be coupled to a differential (20) in order to combine the drive powers of the drive machines, characterized in that - at least one gear (1, 6) of the first transmission (16) is designed as a winding gear, - the first transmission (16) has at least six gears (1, 2, 3, 4, 5, 6), - at least the first and the sixth gear (1, 6) of the first transmission (16) are designed as winding gears.

Description

The invention relates to a transmission arrangement for a hybrid drive.In modern motor vehicles, various drive concepts are combined with one another in so-called hybrid drives. It is known, for example, to support an internal combustion engine with the aid of an electric motor and vice versa.With the aid of transmission arrangements, the power of the drive engines is passed on to the wheels of the vehicle to be driven. In this case, there is a requirement to operate the respective motors as efficiently as possible.Hybrid drives with various transmission arrangements are known from patent documents DE 10 2007 029 610 A1, DE 10 2011 101 410 A1 and EP 2 087 257 B1.It is an object of the present invention to provide an improved transmission arrangement for a hybrid drive.The aforementioned object is achieved by a transmission arrangement for a hybrid drive, having a first transmission which is designed as a dual clutch transmission and is provided to be coupled to a first drive engine, in particular an internal combustion engine, and having a second transmission which is provided to be coupled to a second drive engine, in particular an electric motor, wherein the first and the second transmission can be coupled to a differential in order to combine the drive powers of the drive engines.When the coupling of the gears and / or the shafts of the gears is mentioned here, this means the production of a path for power transmission within the gear arrangement between at least two gear shafts via one or more gear stages.Both the first and the second transmission can transmit the power provided by the respective drive engines directly to a differential, respectively. That is to say, in this case, the torques are only added at the differential in the region of the transmission output of the respective transmission.The combination of the torques or the drive powers on the output side has the advantage that as few components as possible, in particular only the differential, are acted upon by the total torque which results from the sum of the torques of the first and the second drive machine. The transmission arrangement can thereby be made more compact and lighter.In addition, the gears of the first transmission can be freely combined with the gears of the second transmission, so that the torque provided by the drive engines can be adjusted more finely overall. The gears or gear wheel pairs of the first transmission and the gears or gear wheel pairs of the second transmission can be shifted separately from one another and can be coupled independently of one another to the output or the differential.According to a further development of the transmission arrangement, the second transmission is an automatic transmission capable of powershifting.The combination of a dual clutch transmission with a powershiftable automatic transmission in a transmission arrangement achieves the result that both the gears assigned to the first drive engine and the gears assigned to the second drive engine are powershiftable. The gear changes in the first and the second transmission preferably take place without interruption of the tractive force.In other words, a power of a drive machine introduced at the transmission input of a respective transmission can be transmitted permanently to the transmission output of the respective transmission even during the shifting process with the aid of powershiftable clutches.The transmission arrangement can preferably be an automatic transmission, in particular for cross-installation. The transmission arrangement is suitable for installation both in the rear and in the front region of a vehicle.In the transmission arrangement, at least one gear, in particular at least two gears, of the first transmission are designed as winding path gears. In this way, the dual clutch transmission can be made more compact, since six gears can be realized with, for example, four gearwheel pairings in the first transmission.The first transmission may include an input shaft having two sub-transmission shafts and an output shaft.In order to form a winding path gear, at least one shifting element can be provided which is designed to couple at least two idler gears of two gear wheel pairings arranged adjacently on the output shaft in a rotationally fixed manner relative to one another, wherein the two idler gears are still freely movable or rotatable relative to the output shaft in the coupled state to one another. The correspondingly associated fixed wheels of the gear wheel pairings are arranged on different partial transmission shafts.A torque introduced, for example, into a first partial transmission shaft is initially transmitted from a first fixed gear, which is assigned to this partial transmission shaft, to the two coupled loose gears. Via the coupled loose wheels, which are freely rotatable relative to the output shaft, the drive power is transmitted back to a second fixed wheel, which is assigned to a second partial transmission shaft. The second subtransmission shaft is therefore driven by means of the first subtransmission shaft, wherein a transmission or reduction of the drive rotational speed and of the drive torque takes place via the gear wheel pairings arranged in the force flow.Finally, the power is transmitted from the second partial transmission shaft via a third gear wheel pairing in a conventional manner to the output shaft. Each of the three gear wheel pairings involved, taken alone, likewise forms one gear of the dual clutch transmission, with the result that, overall, four gears can be realized with three gear wheel pairings.The first transmission preferably has at least two winding path gears.The second drive machine can be an electric motor which can be coupled to the first drive machine and can be operated as a generator. The first prime mover may therefore be used to charge a battery associated with the electric motor. Alternatively or additionally, it is possible to conduct power from the differential into the electric motor operating as a generator, in particular for the purpose of recuperation.In principle, it may be provided to enable a generator operation of a hybrid vehicle equipped with a transmission arrangement in question here during driving operation and / or when the vehicle is stationary.In particular, the transmission arrangement can have additional coupling means in order to enable generator operation when a vehicle equipped with the transmission arrangement is at rest.The coupling means for transmitting the power of the internal combustion engine via the first transmission to the second transmission can have, for example, an additional spur gear stage, a chain drive or similar devices for power transmission.For example, the output shaft of the first transmission can have a loose wheel, via which the second transmission can be coupled to the first transmission in generator operation.The idler gear provided for the generator operation can in principle be a separate gear wheel which is independent of the gear wheel pairs of the first transmission. According to one embodiment of the invention, however, the loose wheel provided for the generator operation is a gear wheel of a gear of the first transmission, to which a shift element is assigned in order to connect the gear wheel to the output shaft of the first transmission in a rotationally fixed manner.In the case of the rotationally fixed connection of the loose wheel to the output shaft, a drive power introduced into the first transmission can be transmitted to the output shaft of the first transmission. In this case, a portion of the drive power can be transmitted via the loose wheel fixed relative to the output shaft to the electric machine operating in the generator mode.In the state decoupled from the output shaft, the idler gear can serve on the one hand for parking and on the other hand for charging a battery during driving operation. The output shaft is "bridged" by the idler gear, so that no torque is transmitted to the output shaft via the idler gear. Rather, the idler gear in this case serves exclusively for transmitting the drive power to the second transmission. At the same time, a drive power can be introduced into the output shaft via a gear wheel pairing separate from the loose wheel.In the transmission arrangement, the first transmission has at least six gears, wherein the second transmission alternatively or additionally has at least one, preferably at least two gears. The gears of the first transmission and of the second transmission can in particular be freely combined with one another or shifted independently of one another.In order to achieve the most compact design possible, at least the first and sixth gears of the first transmission are designed as winding path gears.According to further embodiments of the invention, it is possible to provide more than six gears, for example up to twelve gears or more, for the first transmission. In particular, more than two winding paths can be provided.Alternatively, the first transmission may have less than six, for example five, four or less gears.Alternatively or additionally, the second transmission can have more than two gears, in particular up to twelve gears or more.It is possible to shift the immediately successive gears of the first dual clutch transmission without interruption of the tractive force.A connection of the second transmission to a differential, which connection takes place independently of the first transmission, can additionally enable a gear change between the even or odd gears of the first transmission without interruption of the tractive force. In this way, the driving comfort can be further increased.For example, during a gear change or shifting process in the first transmission, wherein shifting is performed directly from the second gear to the fourth gear, the traction force interruption, which occurs in this case due to the decoupling of the corresponding partial transmission shaft of the first transmission from the output shaft, can be compensated for by engaging or increasing the torque of the second drive machine.The invention is described in more detail below with reference to a drawing. The following are shown:FIG. 1 shows a schematic illustration of a transmission arrangement according to the invention, andFIG. 2 shows the schematic illustration of the transmission arrangement from FIG. 1, wherein a load path for the parking store is shown.FIG. 1 shows an internal combustion engine 10 and an electric motor 12 which are connected to one another via a transmission arrangement 14 for a hybrid drive which is provided for driving a motor vehicle (not shown).The transmission arrangement 14 has a first transmission 16, which is designed as a dual clutch transmission and is connected on the drive side to the internal combustion engine 10, and a second transmission 18, which is capable of load shifting and is connected on the drive side to the electric motor 12.The transmissions 16, 18 collectively drive the axle differential 20. The drive powers introduced into the gears 16, 18 on the drive side are therefore first combined or summed at the differential 20. Each transmission 16, 18 only has to transmit the speeds and torques introduced on the drive side.In comparison with solutions which already provide for the integration of the electric motor, for example directly between the internal combustion engine and the first transmission, the transmissions must therefore bear significantly lower loads and can be constructed in a more compact, lighter and more cost-effective manner.In addition, the separate connection of the electric motor 12 via an additional, separate transmission 18 has the advantage that the gears of the transmissions 16, 18 can be shifted independently of one another and can therefore be freely combined. Consequently, the cumulative torque applied in the region of the differential 20 can be set in finer gradations.The first transmission 16 has an input shaft 21 which has two partial transmission shafts 1.TGW, 2.TGW and an output shaft 22.The transmission 16 has a dual clutch 24, wherein the partial transmission shafts 1.TGW, 2.TGW can be coupled to the internal combustion engine 10 by means of the dual clutch 24.The dual clutch 24 has two clutches 1.KPL, 2.KPL, wherein the clutch 1.KPL is assigned to the partial transmission shaft 1.TGW and the clutch 2.KPL is assigned to the partial transmission shaft 2.TGW.The dual clutch transmission 16 has six gears 1, 2, 3, 4, 5, 6.The gears 1 and 6 are designed as winding path gears, wherein the force flow for the winding path gear 1 is described below. For improved traceability, the force flow is illustrated by the dashed line in the region of the dual clutch transmission 16 in FIG. 1.The internal combustion engine 10 introduces a drive power into the partial transmission shaft 2.TGW via the clutch 2.KPL of the dual clutch 24. Via a toothing 26 which is assigned to the 3rdgear, the drive power is transmitted to a loose wheel 28 which is likewise assigned to the 3rdgear.The idler gear 28 is coupled in a rotationally fixed manner via a shifting element 2.SE to an idler gear 30, which is assigned to the fourth gear 4. It is decisive here that the shift element 2.SE only fixes the idler gears 28, 30 relative to one another, but the combination of the idler gears 28, 30 created in this way is still freely rotatable relative to the output shaft 22 of the dual clutch transmission 16.Via the loose wheel 30, the drive power is transmitted to a toothing 32, which is likewise assigned to the fourth gear. The tooth sets 26 and 32 are arranged on different subtransmission shafts 1.TGW, 2.TGW, so that the subtransmission shaft 1.TGW is driven via the subtransmission shaft 2.TGW.Starting from the 1 TGW, the drive power is transmitted via the gears 34, 36 in a conventional manner to the output shaft 22. By the additional path via the gears 26, 28, 30, 32 of the third and fourth gears 3, 4, the torque introduced by the internal combustion engine into the partial transmission shaft 2.TGW is additionally transmitted (or reduced) before transmission to the output shaft 22.The gear wheels 34, 36 can therefore, on the one hand, form the second gear 2 of the dual clutch transmission 16 when the partial transmission shaft 1.TGW is directly driven by the internal combustion engine 10 and can additionally, in cooperation with the gear wheel pairs of the third and fourth gears 3, 4, realize the first gear of the dual clutch transmission 16.The above explanations can be transferred in an analogous manner to the sixth gear 6, wherein here instead of a shifting element 3.SE assigned to the first and second gear 1, 2, a shifting element 1.SE assigned to the fifth and sixth gear 5, 6 is used in order to establish a rotationally fixed coupling of the respective idler gear of the first and second gear (idler gear 36) or fifth and sixth gear (idler gear 52) to the output shaft 22. A further difference consists in the fact that the drive torque of the internal combustion engine 10 is initially introduced into the partial transmission shaft 1.TGW and is then transmitted to the partial transmission shaft 2.TGW.Therefore, only three shift elements 1.SE, 2.SE, 3.SE and four gear wheel pairings are required in order to realize six gears in the dual clutch transmission 16.The drive power of the internal combustion engine 10 is transmitted to the differential 20 via an output wheel 38 of the output shaft 22.The second transmission 18 has an input shaft 40 and an output shaft 42; the output shaft 42 is likewise connected to the differential 20 via an output wheel 44.The dual clutch transmission 18 has two gears EM 1, EM 2, wherein a clutch 3.KPL and a clutch 4.KPL are part of a clutch arrangement 46 capable of load shifting, which ensures a shift under load between the gears EM 1 and EM 2 without interruption of the tractive force.The gears EM 1, EM 2 of the second transmission 18 are therefore capable of being shifted as load as the gears 1, 2, 3, 4, 5, 6 of the first transmission 16.The connection of the second transmission 18 to the differential 20 that takes place independently of the gears 1, 2, 3, 4, 5, 6 of the first transmission 16 enables a gear change between the even or odd gears of the dual clutch transmission 16 without interruption of the tractive force.For example, during a gear change or shifting process in the first transmission 16, wherein a shift is made directly from the second gear 2 to the fourth gear 4, the traction force interruption in the first transmission, which occurs due to the decoupling of the corresponding partial transmission shaft 1.TGW of the first transmission 16 from the output shaft 22, can be compensated by engaging or increasing the torque of the second drive machine 12.In addition, the transmission 18 has a loose wheel 48 for the parking charging functionality, which is provided for charging a battery (not shown) assigned to the electric motor 12. For this purpose, the loading gearwheel 48 is connected to the first transmission 16, in particular to a loose gearwheel 52, via a coupling 50, which is indicated merely by a dashed line. The electric motor can therefore be operated as a generator 12.In order to establish the force flow between the loose wheel 48 and the electric motor 12, a clutch 5.KPL is provided. In FIG. 2, the force flow or the torque transmission from the internal combustion engine 10 to the electric machine 12 during parking is illustrated by the dashed line.

Claims

Transmission arrangement for a hybrid drive, having a first transmission (16) which is designed as a dual clutch transmission and is provided to be coupled to a first drive engine, an internal combustion engine (10), and a second transmission (18) which is provided to be coupled to a second drive engine, it being possible for the first and the second transmission (16, 18) to be coupled to a differential (20) in order to combine the drive powers of the drive engines, characterized in that - at least one gear (1, 6) of the first transmission (16) is designed as a winding path gear, - the first transmission (16) has at least six gears (1, 2, 3, 4, 5, 6), - at least the first and the sixth gear (1, 6) of the first transmission (16) are designed as winding path gears.Transmission arrangement according to Claim 1, characterized in that the second transmission (18) is an automatic transmission capable of powershifting.Transmission arrangement according to Claim 1 or 2, characterized in that at least two gears (1, 6), of the first transmission (16), are designed as winding-path gears.Transmission arrangement according to one of the preceding claims, characterized in that the first transmission (16) has an input shaft (21) which has two partial transmission shafts (1.TGW, 2.TGW) and an output shaft (22).Transmission arrangement according to one of the preceding claims, characterized in that the second drive machine is an electric motor (12) which can be coupled to the first drive machine and can be operated as a generator.Transmission arrangement according to Claims 4 and 5, characterized in that the output shaft (22) of the first transmission (16) has a loose wheel (52), via which the second transmission (18) can be coupled to the first transmission (16) in the generator mode.Transmission arrangement according to Claim 6, characterized in that the loose wheel (52) is a gear wheel of a gear (5, 6) of the first transmission (16), to which a shift element (1.SE) is assigned in order to connect the gear wheel (52) in a rotationally fixed manner to the output shaft (22) of the first transmission (16).Transmission arrangement according to one of the preceding claims, characterized in that the second transmission (18) has at least one gear (EM1, EM2).Transmission arrangement according to one of the preceding claims, characterized in that the second transmission (18) has at least two gears (EM1, EM2).

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