WO2011076311A1 - Transmission arrangement and motor vehicle - Google Patents

Abstract

The invention relates to a transmission arrangement for a hybrid vehicle, comprising: a differential (14) having three differential shafts, namely a differential input shaft (14E) and a first and a second differential output shaft (14A1, 14A2), the differential input shaft being coupled to a transmission input shaft (10) that can be coupled to an internal combustion engine, and the first differential output shaft (14A1 ) being coupled to a transmission output shaft (12) that can be coupled to the output of the hybrid vehicle, two of the differential shafts (14E, 14A1, 14A2) being able to be coupled to each other by means of a first controllable coupling device (k1); and a variator (16) having an input shaft that is coupled to the second differential output shaft (14A2), and an output shaft (16A) that is coupled to the first differential output shaft (14A1) and to the transmission output shaft (12) via the node (18). A second controllable coupling device (K2) is arranged between the first differential output shaft (14A1) and the node (18).

Description

 description

Gear arrangement and motor vehicle

Field of the invention

The invention relates to a transmission arrangement for a hybrid vehicle, comprising

 a differential comprising three differential shafts, namely a differential input shaft and first and second differential output shafts, the differential input shaft having a transmission input shaft coupleable to an engine and the first differential output shaft connected via a node to the output coupled to the hybrid vehicle coupled transmission output shaft and wherein two of the differential shafts are coupled to each other by means of a first controllable coupling device,

 a variator whose variator input shaft is coupled to the second differential output shaft and whose variator output shaft is coupled via the node to the first one

 Differential output shaft and coupled to the transmission output shaft.

The invention further relates to a motor vehicle, comprising an internal combustion engine, a transmission arrangement of the aforementioned type and an output, wherein the

Internal combustion engine with the transmission input shaft and the output with the

Transmission output shaft are coupled.

State of the art

Such transmission structures, e.g. from DE 100 04 0812 A1 are known as simple power-split transmission with input-side differential - short ELVeD - and additional, purely mechanical gear.

Vehicle transmissions in general make it possible to adapt a delivery map generated by the internal combustion engine to a demand map required on the driven axle or the driven axles by converting the rotational speed and torque. A stepless conversion is possible for example by an electric transmission, wherein an am

Combustion engine arranged generator is used to generate electricity, which drives one or more arranged on the output electric machines in the motor Operation generate the required torque at a suitable speed. In special driving situations, however, the machine operating predominantly as a generator can also operate as a motor, or the machine or machines operating predominantly as a motor can operate as a generator. Such electrical transmission units of two interconnected via a suitable power electronics electrical machines are known as electrical variators. By adding an electrical energy storage higher

Storage capacity can be a hybrid powertrain with known additional functions of a hybrid vehicle realize.

Instead of electric machines, hydraulic machines, e.g. Axial piston, radial piston, gear and / or vane machines are used. This is called a hydraulic variator.

Especially in hybrid vehicles, the entire must in extreme driving situations

combustion engine power into electrical power and then be converted back into mechanical power. This is usually a big one

Dimensioning of the electrical machines required, which is associated with high costs and unfavorable transmission efficiencies in many operating conditions.

This problem is in the prior art with the principle of so-called

Power split encountered. In this case, the output from the engine power by a differential that is often designed as a planetary gear, but for example, as a not supported on the housing electrical machine can be realized divided. Only part of the engine power is passed through a branch with the two electric machines with torque and speed conversion. The remaining power is fed via one or more mechanical power branches with constant translation to the output. On the output side, the powers of the branches are combined at a so-called node, which can be designed, for example, as a shaft-hub connection or gear stage. As a basic type of such a power split the so-called simple power split with input-side differential, in short ELVeD known.

ELVeD transmissions have the disadvantage that a design of the variator so that the

Vehicle in the entire translation range can be operated near an optimal operating point, hardly possible.

It is therefore known to cover at least work areas high Dauerzugmomente by an additional, purely mechanical gear, which serves at high vehicle speeds for purely mechanical transmission of the moment of the internal combustion engine to the output. However, this solves the problem only selectively. It is typically realized by a coupling of two differential shafts, which prevents the power split and the planetary gear differential of the differential with low loss circulates as a block. In the abovementioned DE 100 04 0812 A1, the "first" clutch device serving for this purpose is designed as a complex 4-state clutch, wherein in the cited document the only purpose of the mechanical gear is torque compensation in the event of failure of both electric machines. Fig. 1 shows a simplified Wolf diagram of the known transmission, which are not relevant to the present invention, the coupling elements of

For clarity, are not shown.

The disadvantage here is that at high vehicle speeds in purely electrical operation, i. at a stationary internal combustion engine, very high speeds of the input side

electrical machine occur. Thus, the maximum vehicle speed in electric driving is determined by the maximum speed of the input side, i. the first electric machine restricted. This is not avoided by a - basically known - Abkoppelbarkeit the internal combustion engine by means of a arranged in front of the differential input shaft coupling device, since the restart of the

Combustion engine this must be reconnected.

task

It is the object of the present invention to develop a generic transmission structure in such a way that the maximum vehicle speed during electric driving is not limited by a design-related maximum speed of the first electric machine.

Presentation of the invention

This object is achieved in conjunction with the features of the preamble of claim 1, characterized in that between the first differential output shaft (14A1) and the node (18), a second controllable coupling device (K2) is arranged.

The basic idea of the present invention is to allow simultaneous decoupling of the differential and internal combustion engine from the drive. As a result, the drag losses are significantly reduced in purely electrical operation.

Also allows second coupling device of the invention, a particularly ^■ advantageous start of the engine from the electric-only mode. In purely electrical operation, the output side electric machine of the variator is operated by a motor. The second coupling device is open. Internal combustion engine and input side electrical machine of the variator stand still. The state of the first

Coupling device that locks the differential is irrelevant in this driving situation. To start the internal combustion engine from this purely electrical operation, however, the first coupling device for locking the differential must be closed. Subsequently, the internal combustion engine with the input side electric machine, which is operated by a motor, accelerated to ignition speed and started. In this case, an engine start without reacting to the output torque (Summenradmoment) is possible because due to the opened second coupling device no mechanical connection between

Internal combustion engine, differential and input-side electric machine on the one hand and the output on the other. Thus, the disadvantage of other Leistungsverzweigter

Transmission structures avoided in which the first differential output shaft

Torque of the input side electric machine to start the engine as. negative torque is transmitted to the transmission output, which is due to the

output side electric machine would have to be compensated and required a good knowledge of the present torques. This would be an additional expense to the exact

Make determination of the actual engine torque required. In addition, the output side electric machine would have such a high at the start of the engine

Apply compensation moment that for this your maximum torque and power would have to be particularly high dimensioned, resulting in space, weight and

Cost disadvantages would result. After the start of the internal combustion engine with open, according to the invention, second coupling device is the first

Coupling device opened, i. the differential is released. Afterwards the speeds are synchronized. This can be done "digitally" because of the synchronized speeds, ie without any special control method.

In a development of the invention, it is provided that a third controllable coupling device is arranged between the variator output shaft and the node. The idea behind this development is to decouple the output-side machine, in particular the electric machine of the variator from the output, when the purely mechanical, long gear, in which the vehicle is driven purely by internal combustion engine, is inserted. Through this decoupling, the translation, with which the

Output side machine is coupled to the output, are selected so high that the machine contributes in medium and slow driving situations, even a high torque to the output. In particular, it is avoided that it is carried along uselessly by the output at high speeds, with its maximum speed could easily be exceeded at a high gear ratio. Another advantage of said training is in the prevention of drag losses of the output engine of the variator. These are currently at the most widespread in the automotive field permanent magnet excited

Synchronous machines particularly high.

The freedom obtained by the additional decoupling freedom in the translation, with which the output side engine of the variator is coupled to the output can, as provided in a preferred embodiment, be used by the variator output shaft via a gear ratio with an input element of the third coupling device connected is. Such an additional translation stage may be used, for example, as an additional planetary gear, e.g. one in which one of its shafts is braked by means of a controllable brake with respect to a transmission housing or fixedly connected to the transmission housing.

In a further development of the invention, it is provided that not with the first

Coupling device connected differential shaft can be coupled by means of a fourth coupling device with one of the other differential shafts. This corresponds to the realization of a second purely mechanical gear. This second purely mechanical gear is preferably designed for a different driving speed range than the first purely mechanical gear. The latter is, as described above, preferably provided with a long translation and intended for high speeds. The second mechanical gear, however, can preferably couple the internal combustion engine with a very short gear ratio to the output, so that with him driving situations low driving speed and high

Dauerzugmomente, for example, mountain travel with trailer, can be covered. To realize the desired translation, the fourth coupling device may be preceded or followed by a corresponding translation stage.

Conveniently, at least one of the coupling devices is designed as a positive coupling. For example, this may be a preferably synchronized jaw clutch. Positive-fit couplings, in contrast to conventional friction clutches wear less and require less space.

Further features and advantages of the invention will become apparent from the following, specific description and the drawings.

Brief description of the drawings

Show it:

FIG. 1: Wolf diagram of a transmission structure according to the prior art, FIG. 2: Wolf diagram of a transmission structure according to the invention according to a first embodiment,

Figure 3: Wolf diagram of a preferred embodiment of the transmission structure of FIG

 2,

FIG. 4: Wolf diagram of an alternative development of the transmission structure of FIG. 2,

FIG. 7 shows a schematic representation of the transmission structure of FIG. 3,

FIG. 8 shows a schematic illustration of a further embodiment of the transmission structure of FIG. 3.

Detailed description of preferred embodiments

In the context of the present invention, the term "coupled" means that an active connection path is generally provided between two elements described as "coupled". This operative connection path may include both non-rotatable connections and connections allowing relative rotations, e.g. Translation levels include. Furthermore, it is not necessary for the active connection path to exist permanently. In particular, coupling devices can be provided between two elements described as "coupled", which can interrupt the operative connection path at least temporarily.

The term "couplable" in the context of the present description means that the

Actual connection between two elements described as "coupled" mandatory has an interface that temporarily or by structural coupling by a coupling device

Measures can be closed permanently.

Figure 1 shows a Wolf diagram of a transmission structure according to the prior art. The transmission input shaft 10 is, in particular in the context of the installation of the transmission structure in a motor vehicle, with the internal combustion engine, in particular the crankshaft, coupled. The same applies to the transmission output shaft 12, which can be coupled to the output of the motor vehicle, in particular to the axle differential of a driven axle of the motor vehicle. The transmission structure comprises a differential 14, in particular as

Planetary gear can be formed and comprises at least three shafts, namely a differential input shaft 14E, a first differential output shaft 14A1 and a second differential output shaft 14A2. The planetary gear 14 is followed by a variator 16, in the preferred embodiment comprises a first electric machine 161 and a second electric machine 162, between which a controllable power electronics is provided. Typically, an electrical energy store is also connected to the variator. The variator 16 is connected to the second via its variator input shaft 16E

Differential output shaft 14A2 coupled. The variator output shaft 16A is coupled to the transmission output shaft 12 via a node 18. The node 18 can open

different way, e.g. be designed as a shaft-hub connection, gear stage, transmission gear, countershaft, etc. Also coupled to the node 18 is the first differential output shaft 14A1 of the differential 14. To realize a purely mechanical gear, the differential input shaft 14E and the first differential output shaft 14A1 may be interconnected via a first clutch device K1 so that the differential 14 is locked and lossless without inner relative movements circulates as a block.

The reference numbers introduced in connection with FIG. 1 designate corresponding elements in the remaining figures in the further course.

FIG. 2 shows a first embodiment of a transmission structure according to the invention. This differs from the known transmission structure according to Figure 1 by a second coupling device K2, the node 18 with the free, i. the differential shaft not coupled to the other differential shaft by the first coupling device couples. In the embodiment of Figure 2, this is the first differential output shaft 14A1. By means of the second coupling device K2 can in the case of purely electrical operation of the

Vehicle, the internal combustion engine, the differential 14 and the first electric machine 161 are completely decoupled from the output. This allows, in particular, a start or restart of the internal combustion engine under optimized conditions, regardless of the vehicle speed.

Furthermore, the embodiment of FIG. 2 has an optional (dashed line) third coupling device K3 between the variator output shaft 16A and the node 18.

In this way, a decoupling of the output-side electric machine 162 in the case of vehicle operation in purely mechanical gear, by closing the first

Coupling device K1 is realized, allows. As a result, the drag losses of the second electric machine 162 are avoided. In addition, it is possible, via a not shown in Figure 2, additional gear stage to couple the output side electric machine 162 with high gear ratio to the transmission output shaft 12, which without the third

Coupling device K3 due to the limited maximum speed of the electric

Machine 162 would not be possible at high vehicle speeds. The embodiments of Figures 3 and 4 extend the previously described

Transmission structures to another purely mechanical gear, by the fourth

Coupling device K4 is realized. This couples two different differential shafts as the first coupling device K1. Alternatively, the same waves could be coupled as by means of the first coupling device K1, but with a different intermediate gear ratio. Basically, the coupling of two differential shafts, regardless of which particular waves are coupled, the same effect, namely the locking of the differential. Characterized in that by the coupling devices K1 and K4, however

Differential waves can be coupled to different Wirkverbindungspfaden, these paths could be designed differently, in particular different

Realize translations to the output. In particular, it is possible, for example via the first clutch device K1 to realize a "long" gear, which at high

Vehicle speeds a purely mechanical power transmission of the

Combustion engine allows for downforce. In contrast, the second purely mechanical gear realized by the fourth clutch device K4, a short

Translation and in particular be used when high Dauerzugleistungen at low vehicle speeds, which would overload the electric machines, are required. Corresponding translation stages, e.g. as spur gears or

Planetary gear can be formed, are not shown in Figures 2-4, but can be easily inserted at any point.

The differences between the structures of Figures 3 and 4 exist only in the place of coupling to the output. Preferably, the coupling in the region of the node 18 (Figure 3). In principle, however, the coupling in front of the third coupling device K3, i. between this and the Variatorausgangswelle 16 A. In this variant, however, in the second mechanical gear, no decoupling of the output-side electric machine 162 would be given. However, if the second mechanical gear, as described above, designed for low vehicle speeds, this would not be an obstacle. On the contrary, at low vehicle speeds, depending on the torque demand, the crossfade could be between purely mechanical and boosted, i. combined with electric drive combined combustion engine drive, be facilitated.

Figure 5 shows a schematic representation of the transmission structure of Figure 3. The node 18 is realized here as a drive shaft with three input and one output pinion. Incidentally, the individual elements are readily identifiable by using the already introduced reference numerals. The structure of FIG. 6 differs from that of FIG. 5 in that an additional planetary gear 20 is provided between the output-side electric machine 162 and the third clutch device K3 as a gear stage for the electric machine 162. The sun of the planetary gear 20 is permanently fixed via the gear housing.

Of course, the embodiments discussed in the specific description and shown in the figures represent only illustrative embodiments of the present invention. Those skilled in the art will be aware of a broad spectrum in light of the disclosure herein

Possible variations based on. In particular, the explained features can be combined individually or in groups with each other to create new transmission structures. It is also possible in principle, in each case in each case assigned to a respective coupling device, to arrange transmission stages for adapting the relative speeds to the respective application area. Also, the special design of the

Coupling devices must be selected by the expert in the light of the specific task with regard to wear, space, torque transmission, etc. Particularly advantageous is the use of positive instead of frictional clutches considered.

LIST OF REFERENCE NUMBERS

10 transmission input shaft

 12 transmission output shaft

 14 differential

 14E differential input shaft

 14A1 first differential output shaft

 14A2 second differential output shaft

 16 variator

 161 first electric machine of 16

 162 second electric machine of 16

16E variator input shaft

 16A variator output shaft

18 knots

 20 additional planetary gear

 K1 first coupling device

 K2 second coupling device

 K3 third coupling device

Claims

claims Transmission arrangement for a hybrid vehicle, comprising  a differential (14) comprising three differential shafts, namely a differential input shaft (14E) and first and second differential output shafts (14A1, 14A2), the differential input shaft being connected to a transmission input shaft (10) coupleable to an internal combustion engine. and the first differential output shaft (14A1) is coupled via a node (18) to a transmission output shaft (2) coupleable to the output of the hybrid vehicle, and wherein two of the  Differential shafts (14E, 14A1, 14A2) by means of a first controllable  Coupling device (K1) are coupled to each other,  a variator (16) whose variator input shaft is coupled to the second differential output shaft (14A2) and whose variator output shaft (16A) is connected via the node (18) to the first differential output shaft (14A1) and to the gearbox Output shaft (12) is coupled, characterized, in that a second controllable coupling device (K2) is arranged between the first differential output shaft (14A1) and the node (18). Gear arrangement according to one of the preceding claims, characterized characterized in that a third controllable coupling device (K3) is arranged between the variator output shaft (16A) and the node (18). Gear arrangement according to claim 2, characterized in that the variator output shaft (16A) is connected via a gear ratio with an input element of the third coupling device (K3). Gear arrangement according to one of the preceding claims, characterized characterized in that the differential shaft (14A2) not connected to the first coupling device (K1) can be coupled to one of the other differential shafts (14E) by means of a fourth coupling device (K4). Gear arrangement according to claim 4, characterized in that the fourth coupling device (K4) is a translation stage upstream or downstream. 6. Gear arrangement according to one of the preceding claims, characterized in that at least one of the coupling devices (K1, K2, K3, K4) is formed as a positive coupling. 7. A motor vehicle, comprising an internal combustion engine, a transmission arrangement with a transmission input shaft (10) and a transmission output shaft (12) and an output, wherein the internal combustion engine with the transmission input shaft (10) and the output to the transmission output shaft (12) is coupled,  characterized,  in that the gear arrangement is a gear arrangement according to one of the preceding claims.