DE102008045583B4 - Automatic transmission with torque converter - Google Patents

Abstract

Automatic transmission (1), with a torque converter (converter 6), which has a drive area (2) in which power can be divided into at least two power branches, one power branch running over the torque converter and which has an output area (output area 3), in which the at least two power branches can be brought together, the torque converter (6) being constructed from at least two electrical machines (7, 8), characterized in that precisely one planetary set (15) is arranged in the output area (3), the coupling structure of which is via two claw clutches (22, 23) is changeable.

Description

The invention relates to an automatic transmission with a torque converter, which has a drive region, in which power can be divided into at least two power branches, wherein a power branch extends over the torque converter, and which has an output region, in which the at least two power branches are merge.

Automatic transmissions with torque converters are well known. Typically, hydrodynamic transducers are used as torque converters, so that combined hydrodynamic-mechanical transmissions are produced, which divide the traction power by means of a differential gear on a power path around the hydrodynamic converter and a pure mechanical power path parallel thereto. The merger of the traction power is then carried out in a further transmission in the output range on a common power path at the transmission output. By way of example, this is on the DE 20 21 543 A1 refer, which describes such a transmission.

These so-called Differenzialwandlergetriebe be used in the drive of vehicles of various kinds. In this case, a plurality of planetary gear sets for the drive region and / or the output region are used in such a transmission, as is usually the case in all automatic transmissions. The planetary gear sets are connected to each other in predetermined fixed coupling schemes and the various ratios of the transmission are then realized via multi-plate clutches or multi-disc brakes. With the slats of the clutches or brakes is thereby achieved that it comes to circuits without interruption of traction.

In such automatic transmissions, the torque converter is typically used to start in first gear. The starting torque is transmitted only at standstill via the converter, while then, as soon as the output starts to rotate, the power flow on the purely mechanical power branch added. Only in second gear is the power typically transmitted purely mechanically and the converter is then no longer used. Another possible use of the hydrodynamic converter is that when braking the vehicle power from the range of the output of the transmission can be introduced backwards into the transmission, so that the hydrodynamic converter can be used in addition as a wear-resistant retarder or retarder.

Hydrodynamic transducers, however, are comparatively expensive in terms of their manufacture and their structural design or design. In particular, when a hydrodynamic converter is to be used on the one hand as a torque converter for starting or the first gear and on the other hand to fulfill the task of a retarder or a wear-free retarder, high demands are placed on the design of the converter.

For further prior art is on the DE 10 2006 044 500 A1 and the EP 1 747 929 A1 directed.

It is therefore the object of the present invention to further develop an automatic transmission with torque converter so that a simplified structure is achieved, which enables energy-efficient operation of the automatic transmission.

According to the invention, this object is solved by the features of claim 1.

By the at least two electric machines, a structure is achieved, which is able to meet all the characteristics of the torque converter with very high flexibility in terms of control. Thus, one of the electrical machines will typically be operated as a generator to convert the power derived from the drive range into electrical power. With this electrical power, the other machine can then be operated by an electric motor to deliver the desired torque to the output range. By means of suitable power electronics, the torque at the electric machine acting on the driven area can be controlled or regulated very flexibly within wide limits.

In the event of deceleration, this at least one electric machine coupled to the output region can also be operated as a generator. By then taken from this generator current that can be adjusted braking torque also controlled and regulated in a simple and flexible manner within wide limits. In addition, braking energy can thus be recovered when braking the output of the automatic transmission via this electric machine. This energy can be temporarily stored in an energy store, so that it can be made available to other electrical energy consumers in the vehicle or can also be used for driving purposes.

According to the invention, exactly one planetary gearset is arranged in the drive region, the coupling structure of which is provided via two jaw clutches is changeable. The structure is so very simple and compact, since a second planetary gear set and a multi-plate clutch can be omitted.

Further advantageous embodiments of the invention will become apparent from the remaining dependent claims and from the embodiments, which are illustrated below with reference to the figures and explained in detail.

Showing:

1 a first embodiment of an automatic transmission according to the prior art;

2 A second embodiment of an automatic transmission according to the prior art;

3 An embodiment of an automatic transmission according to the invention; and

4 an alternative embodiment of the embodiment of the automatic transmission according to the invention.

In 1 is an automatic transmission 1 illustrated in the prior art, with an input area 2 and an exit area 3 , The entrance area 2 represents the drive area on the side of a drive 4 of the automatic transmission 1 is arranged while the output area 3 represents the output range, on the side of the output 5 of the automatic transmission 1 is arranged. Between the entrance area 2 and the exit area 3 is an electrical converter 6 recognizable, which from a first electric machine 7 and a second electric machine 8th consists. The further construction of the automatic transmission 1 corresponds essentially to that of a conventional differential converter transmission, wherein only in place of a hydrodynamic converter of the electrical converter 6 with the two electric machines 7 . 8th occurs.

In the entrance area 2 are common in such automatic transmissions two planetary gear 9 . 10 to recognize which via multi-plate clutches 11 be switched into different coupling structures. This allows different translations in the entrance area 2 realize, as is common in the art. In addition, in the entrance area 2 the power will be split, so this once has a direct mechanical power branch 12 to the downforce 5 passes or alternatively in the area of the electrical converter 6 arrives. That's the first electric machine 7 of the electrical transformer 6 with the entrance area 2 of the automatic transmission 1 coupled. The electric machine 7 can thus with the brake open 13 over the entrance area 2 from the drive 4 are driven. The electric machine 7 is operated as a generator, so that this generates electrical power. The electrical power then passes through an electronic unit, eg. B. a control device 14 , which may include power electronics, to the second electric machine 8th , which in this case will typically be motorized, and which power in the output range 3 of the automatic transmission 1 emits. In the exit area 3 are two more planetary gearboxes 15 . 16 present, which as well as in the prior art together with multi-disc brakes 17 the power of the second electric machine 8th in a suitable manner to the output 5 conduct. In addition, via the plate gear 15 . 16 in the exit area 3 the reverse gear be switched analogous to the prior art. As with prior art differential transformer transmissions, the electric converter will be used for starting and driving in a "long" first gear with increasing mechanical power output. Here is the first electric machine 7 operated as a generator, while the second electric machine 8th is powered by a motor.

In the prior art, the hydrodynamic converter typically used therein also assumes the task of a wear-resistant retarder, including power via the output 5 and the exit area 3 is introduced into the converter. This task can also be done by the electrical converter 6 be taken over. This is done in a comparable coupling structure of the output area 3 as in the prior art, the second electric machine 8th through the downforce 5 driving power applied. By a suitable control of the power extraction from this then operated as a generator electric machine 8th , for example via the control device 14 , the braking torque can then be adjusted. The further advantage of this type of braking is that the braking energy is not obtained as waste heat energy as in a retarder or hydrodynamic converter used as such, but as electrical energy. This electrical energy can be in an electrical energy storage device 18 be cached and for other electrical consumers in the with the automatic transmission 1 equipped vehicle or even for the electric machine 8th to provide additional power to start up during operation of the electrical converter at a later time 6 provide. Alternatively or additionally, the stored electrical energy can also be used to feed additional electrical energy into the drive train in the case of acceleration in any gear, in the manner of a so-called "mild" hybrid.

The energy storage device 18 Of course, it can also be used if, during operation of the electrical converter 6 Excess energy in the region of the then used generically first electric machine is obtained, which should not be used by the second electric machine or can. The energy storage device 18 can be designed as a battery, as a high-performance capacitor or the like, or it can also be appropriate combinations of these components are used.

The electrical converter 6 offers, as already mentioned, the decisive advantage that it has less effort in terms of design than, for example, a hydrodynamic converter. In addition, via the control device 14 The transmission can be adapted very flexibly to the internal combustion engine. This is the possible application of the electrical converter 6 increased compared to a conventional hydrodynamic converter.

In 2 is now another embodiment of an automatic transmission 1 According to the prior art, which in principle has the same structure with input range 2 , electrical converter 6 and exit area 3 as the embodiment according to 1 shows. The difference lies in the design of the entrance area. As already from the German patent application DE 10 2008 010 064 known, the automatic transmission in the entrance area 2 through the use of dog clutches 19 . 20 compared to the state of the art, as for the entrance area in 2 described, be optimized. This structure allows the elimination of one of the multi-plate clutches 11 and a planetary gear set 10 , The remaining, in the case of a four-speed gearbox only planetary gear set 9 is about the jaw clutches 19 . 20 switched in its coupling structure when it transmits no power or no torque. This is then the case, while typically in third gear the power via a through-clutch 21 , which at the same time one of the remaining multi-plate clutches 11 is, over the direct mechanical power branch 12 to the downforce 5 arrives. In this situation, the planetary gear set runs 9 only load-free and transmits at this time no drive torque.

When switching to the next higher gear is the planetary gear set 9 then used with this new switched coupling structure so that the one planetary gear set 9 can provide both coupling structures which otherwise have two separate planetary gear sets 9 . 10 would have been provided. When switching back from the fourth to the third in the second gear, this process takes place in the reverse manner, so that in turn in third gear in preparation for switching back into the second gear, the coupling structure of the then rotating torque-free planetary gear set 9 through the jaw clutches 19 . 20 is changed accordingly.

Otherwise, the automatic transmission shown in the embodiment 2 1 in its construction and its functionality the automatic transmission in 1 comparable. Again, the electrical converter in turn consists of the two electrical machines 7 . 8th , which accordingly as a converter 6 can be used for propulsion or as regenerative braking unit during braking. The electric machine 8th can also be used in all mechanical gears either to support the internal combustion engine or alone power to the output 5 submit.

The two planetary gear sets 15 . 16 in the exit area 3 serve to merge the two line branches in 1st gear, for the appropriate introduction of forces when braking in the converter 6 on the one hand and for the realization of a reverse gear on the other. Because the absorption of braking power by the electric machine 8th can be realized much more flexible, it makes sense to the output area as in 3 shown instead of the two planetary gear sets 15 . 16 according to the invention with only one planetary gear set 15 train. The reverse gear is then replaced by a change in the coupling structure via two more jaw clutches 22 . 23 realized. Together with the second planetary gear set 16 can also be one of the disc brakes 17 eliminated. This construction of the output area 3 , which could also be supported by an additional optional retarder, is fundamentally from the German patent application with the file number DE 10 2008 027 947 known. The further construction of the electrical converter 6 also corresponds here to the structure already set forth in the other figures and the functionality described in detail there, which by the differently configured output range 3 not changed.

In 4 is shown another alternative, in addition to a clutch 24 compared to the execution 3 is provided. This multi-plate clutch 24 is between bridge and sun of the only remaining planetary set 15 arranged. It allows the electric machine 8th with different translations over the exit area 3 on the downforce 5 to pair. This variability of a second translation between the electric machine 8th and the downforce 5 allows it in the design of the electric machine 8th to have to drive less effort, since the additional ratio reduces the required speed spread or alternatively the achievable speed can be increased. In particular, the electric machine can be 8th Optimize better for a smaller operating range, so that in terms of constructive aspects optimized and thus more economical and energy efficient to be designed electric machine 8th can be used.

All illustrated embodiments are to be understood in principle as an example, so the electrical machines 7 . 8th not necessarily in the housing of the automatic transmission 1 be integrated with, they could also be coupled via appropriate transmission elements. Moreover, it is also to be understood by way of example that the control device 14 and the energy storage device 18 (which may also be optional in the construction of a pure converter) are outside the housing of the automatic transmission. These units could be fully or partially integrated in the automatic transmission.

Claims (2)

Automatic transmission ( 1 ), with a torque converter (converter 6 ), which has a drive area ( 2 ), in which power is divisible into at least two power branches, wherein a power branch extends over the torque converter, and which has an output region (output region 3 ), in which the at least two power branches are merge, wherein the torque converter ( 6 ) from at least two electrical machines ( 7 . 8th ), characterized in that in the output area ( 3 ) exactly one planetary set ( 15 ) is arranged, the coupling structure via two jaw clutches ( 22 . 23 ) is changeable. Automatic transmission ( 1 ) according to claim 1, characterized in that the second electric machine ( 8th ) via a coupling agent ( 24 ) in two different translations with the output range ( 3 ) can be coupled.

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