DE10239540A1 - Reverse gear with central synchromesh for load switch transmissions has first-gear countershafts with direct gear connection - Google Patents

Abstract

The reverse gear is for a transmission with input shafts (23, 24) and two countershafts (21, 22) with driven gears (3c, 3d). The first-gear countershaft has at least one direct gear inside the transmission between the input shafts. An extra gear wheel is fitted on the second countershaft directly next to its first gear wheel.

Description

State of the art

In the DE 198 50 549 A1 becomes a multi-speed gearbox 10 (10a) describes the two input shafts 12 . 13 and an output shaft 25 having. Each of the input waves 12 . 13 is with a clutch 29 . 30 connected and with this from the internal combustion engine 11 of the motor vehicle separable. Furthermore, the two input shafts 12 . 13 one or two electrical machines 34 . 35 . 40 assigned and connected to these non-positively, which is based on the internal combustion engine 11 opposite side of the couplings 29 . 30 are located. By means of the electrical machine or machines 34 . 35 . 40 can in particular on a starter and an alternator for the internal combustion engine 11 to be dispensed with. Furthermore, both the synchronous speed of the input shaft 12 . 13 set a target route in a simple way and also implement different operating states. Group power shifts are not possible here and double clutches are required.

In the patent DE 41 02 202C2 (D1) a transmission arrangement is described in which an internal combustion engine directly with the side gear 11 a differential gear 10 connected is. The parallel side gear 12 is via a spur gear 24 . 25 with an electric motor 5 connected. The pinion gears 13 and 14 lead over the pinion shaft 15 and a spur gear 16 . 20 to another gear 3 , The differential gear 10 can neither be blocked nor on one side (side gear 12 ) are fixed so that the side gear 12 always have the same torque as the side gear when the motor vehicle is driven 11 , so that a torque transmission to the pinion shaft 15 can take place. This torque must therefore be permanently from the electric motor 5 to be delivered. The function specified in the description that the electric motor can serve as a generator during the driving process leads to the condition that the pinion shaft 15 (almost) stands and the side gear 12 opposite the side gear 11 turns backwards and drives the generator. For the locomotion of the vehicle must therefore from the electric motor 5 a drive torque is permanently supplied, which will ultimately quickly lead to the discharge of the on-board electrical system battery.

In the published application DE l96 50 723 A1 (D2) a control system for vehicle drive units is presented, in which a motor generator 21 directly with the sun gear of a planetary gear set 30 connected is. The planetary gear set can be via a clutch 36 be blocked. In contrast to the present application, the vehicle drive unit described in D2 requires a starting clutch 31 , the sun gear of the planetary gear set 30 cannot be determined (the planetary set 30 does not have the function of a group transmission for doubling the number of gears) and the motor generator 21 is not used to synchronize the gears of the transmission 4 ,

In the patent DE 196 06 771C2 (D3) a hybrid drive is described in which between the input shaft 1 (connected to the engine) and the output shaft 12 (leading to the drive wheels) two electrical machines 3 and 4 and switchable planetary gear sets 5 . 6 . 16 are arranged. The switchable planetary gears serve as a stepped gearbox and in cooperation with the electrical machines, a switchable stepless gearbox results, which means that favorable operating points can be selected. However, it is a hybrid drive, in which except when the clutch is closed 11 always one from the electric machine 3 Torque generated is necessary for torque transmission, in which no planetary gear set coupled to the electric machine serves as a group transmission for doubling the number of gears, and in which no synchronization processes are carried out with the aid of a planetary gear set and an electric machine.

In the published application DE 198 18 108 A1 (D4) a hybrid drive is also presented, whereby - similar to D2 - an electric machine 2 on the sun gear of a planetary gear set 35 works (see e.g. 2 ) and that this planetary gear set via a clutch 36 can be blocked. Similar to D2, the sun gear of the planetary gear set can 35 cannot be fixed and this planetary gear set therefore does not have the function of a group transmission for doubling the number of gears and the electric machine 2 is not used to synchronize the gears of the transmission 4 ,

The registration WO 98/406 47 relates to a drive unit for motor vehicles with a transmission 18 , wherein the transmission can be coupled to the internal combustion engine via a friction clutch and an electrical machine with the aid of a clutch and an intermediate transmission to the transmission 18 can be coupled. The electric machine serves as a starter motor, as a generator and for gear synchronization. This requires at least two friction clutches and the advantages that are possible with three-shaft operation are not used.

The patent application US 560 32 42 describes a gear arrangement in which at least one electric or hydraulic lathe enables a synchronization of gears with two shafts. At least two friction clutches (or a double-acting friction clutch) are required here and no synchronization processes are possible that span several groups.

The application 199 01 414 (G1) preceding this application describes the integral structure of gears consisting of at least a planetary gear set coupled with at least one (predominantly) unsynchronized countershaft transmission. One shaft of a planetary gear set (here mainly the sun gear shaft) is connected directly to the crankshaft of the internal combustion engine, the second shaft (here mainly the land shaft) is connected directly to the integrated countershaft transmission, while the third shaft (here mainly the ring gear shaft) is connected to a brake and is connected to a lathe. In addition, the planetary gear set can be blocked with a (claw) clutch. This means that several functions can be performed. With the brake and clutch released, the ring gear can be turned with the help of the lathe so that a gear can be synchronized (eg 1st gear when the vehicle is stationary). If the brake is then applied, this gear is activated in the lower group, ie the drive wheels start to move. In this way, all gears of the countershaft transmission can be shifted, which is then the lower group of gears. If the gears of the countershaft transmission are then switched again in sequence - again synchronized via the lathe - and the planetary gear set is then blocked, the upper group of gears is obtained. If two planetary gear sets are each coupled to a countershaft transmission, the gears being assigned alternately to the two planetary gear sets, a power shift without torque interruption is possible in the lower group of gears. In addition to the synchronization tasks, an electric lathe can also take over the functions of starter motor and generator.

The one that preceded this application Additional application 199 21 064 (G2) describes an arrangement of the lathe in alignment with the shaft (s) of the planetary gear (the Planetary gear) with which the lathe is directly connected to the Planetary gear (s) can be coupled. A necessary reduction for the Starter operation takes place via an internal power split of the planetary gear (s). For multi-part designs electric lathes may without additional mechanical switching purely electrically between the functions of synchronization mode, starter mode and generator operation can be switched. Further detail improvements are specified.

The other one preceding this application Additional application 199 33 373 (G3) describes the to the previous registrations simplified construction of a 6-speed gearbox (+ Reverse gear), where the lower 3 courses by actuation can be switched from brakes without torque interruption. Besides, is a possibility installation of the gearbox in the rear area. Further detail improvements are shown.

Preliminary remark on further registrations In the book Alfred Krappel and 26 co-authors crankshaft start generator (KSG) basis for future vehicle concepts expert - publisher Renningen ISBN 3–8169–1808–5
different possibilities and applications of crankshaft start generators (KSG) are described. These are electrical machines that are directly connected to the crankshaft of internal combustion engines of motor vehicles. They can be used both as starters with high torque (at low speeds) and as generators with high power (at higher speeds). In the further additional registrations, the possibilities provided by the KSG are expanded in such a way that the KSG is integrated into the transmission and takes over the additional tasks of transmission synchronization and power shifting. It is therefore called the GSSG transmission synchronization start generator here. Of course, the tasks of gear synchronization and power shifting carried out by the GSSG can also be carried out by a different type of lathe, for example a hydraulic unit.

The other one preceding this application Additional application 199 62 854 (G4) describes applications that take advantage of the high torque of the GSSG, even without planetary gear To be able to carry out synchronization and powershift operations. This is the input shaft of the transmission divided into two sections, each alternating Assigned to gears are. To increase of the starting torque, a friction clutch can be used, otherwise suffice Claw couplings. Arrangements with group gears are described but each group needs its own synchronization and load switching device.

The other one preceding this application Additional application 100 01 602 (G5) describes other applications, who use the high torque of the GSSG for synchronization and powershift operations, but now again using at least one planetary gear set. In contrast to the applications in G1, G2 and G3, it is now sufficient but a single or a double acting planetary gear set for all powershift operations, while in G1, G2, G3 for Powershift two panette sets are required and load switching only in the lower group possible are.

The gearbox described with other groups need for every additional group each have their own synchronization and load switching devices.

The additional application 100 13 734 (G6) preceding this application describes further applications which take advantage of the high torque of GSSG for synchronization and powershift operations. Here, any number of group transmissions can be connected in series, all of which are synchronized and powershifted by a single GSSG. The are Variants designed for a relatively large number of gears and the return of shaft 13 on wave 1 can be difficult. In addition, not all possible gears are used.

The one that preceded this application Additional application 100 21 837 (G7) describes extensions and refinements registration G7 and nested gearbox designs.

The other one preceding this application Additional application 100 34 656 (G8) describes the application of KSG in boats, mainly in sailing boats. In addition to his previous one The KSG serves tasks as a clutch replacement, as an electric drive and as a wave generator.

The previous application 100 62 693.9 (G9) describes power shift group transmissions, in which a GSSG 9 is an integral part. Simplified design options are given for a main and a subgroup, whereby there are no eccentric countershafts and only geometrical gear gradations are used.

The one that preceded this application Additional application 101 33 629.2 (G10) describes powershift transmission, the above an additional eccentric countershaft forward and create multiple reverse gears. Here is not a shortened Hollow shaft used and the auxiliary shaft is via additional gears or Shift sleeves returned.

In the patent DE-195 24 233 C2 describes a six-speed gearbox with 2 countershafts and an additional shaft for the reverse gear, two output gears are used and one gear of the input shaft is responsible for two gears. Here the advantages of an eccentric countershaft are not used and no load switching is possible.

The one that preceded this additional application Additional application 101 41 309.2 describes powershift transmissions with eccentric Besides waves. However, these gears are much more voluminous than that Transmission of this application.

The one that preceded this additional application Additional application 101 45 790.1 describes short powershift transmissions, which, however, require a gearwheel level more than the gearboxes presented here.

The one that preceded this additional application Additional application 101 50 522.1 describes short powershift transmissions, but which need more shift sleeves than the gearbox presented here.

The one that preceded this additional application Additional application 101 54 955.5 describes short powershift transmissions, who also need more gear sleeves than the ones presented here Transmission.

The one that preceded this additional application Additional application 101 57 791.5 describes short 6-speed gearboxes, which also require more shifting elements than the gears presented here. The previous application 102 06 preceding this additional application 584.5 describes short powershift transmissions, but none possibility the central synchronization.

The one that preceded this additional application Additional application 102 25 331.5 describes short powershift transmissions with a countershaft and a countershaft, with the possibility of central synchronization for further Gears are used. As a result, the starter generator connection is not advantageous in all operating states and there are no cheap ones possibilities for reverse gears, like they are described in this application.

Preliminary remarks Two transmission variants with 7 forward gears each with progressive gear gradations are presented as an example (whereby the 7th gear can also be omitted). Both gearbox variants have two countershafts 21 and 22 (as known), their rotation over the two with the gear 3e meshing gears 3c and 3e to the wave 13 is transmitted (which leads to the drive wheels, not shown).

Due to the two countershafts 21 and 22 there are favorable possibilities for a reverse gear, which manages with an additional gear and a shift element coupled with a forward gear. Examples are described in the variants. Basically there is also the possibility to replace a gear wheel of a forward gear with a sliding wheel, then the reverse gear does not require an additional gear wheel (see description of variant 2 ).

The central synchronization takes place via a shaft 50 (as with registration 102 25 331.5), with the omission of additional gears via this shaft 50 enables a cheaper connection of a starter generator. What has to be considered with two countershafts is also described in the variants. You can also use the shaft if necessary 50 further gears are made possible.

In both variants, 2 of the 4 double-acting switching elements (for a total of 8 gears) are each on the shaft 21 and 2 the wave 22 assigned. This enables all switching elements to be actuated from the inside of the associated shaft (eg after registration 102 25 331.5). The switching element for the reverse gear and the associated forward gear must be adapted to the respective requirements.

As is known, the transmission variants have two input shafts 23 and 24 which, for example, can be coupled to the crankshaft of an internal combustion engine in a rotationally fixed manner via double clutches (which enables load shifting). In both variants, 1st gear works via a shaft 24 and reverse gear while 1 is still on. Gear through the gears of the 1st gear from the shaft 23 forth (with the shaft rotating backwards 24 ), which enables that 1st and reverse gear can be switched on at the same time and only activated by alternating actuation of the double clutches.

The switching elements are e.g. about electrical, pneumatic or hydraulic actuators using a electronic control unit switched.

The reference numerals are largely adapted to the previous registrations. This results in Gaps in the order of numbering.

description the invention

The description is based on the associated Principle drawings. Show it

1 Schematic diagrams of a 7-speed transmission with progressive gear gradations in one variant 1

2 Schematic diagrams of a 7-speed transmission with progressive gear gradations in one variant 2

variant 1

In the 1a ) outlined variant 1 is a 7-speed powershift transmission with progressive gear ratios in countershaft design with 2 countershafts 21 and 22 and the two input shafts 23 and 24 , The central synchronization takes place via shaft 50 , with the wave 50 connected component 60 can be a starter generator or a rotary connection possibility to a starter generator. That to the countershaft 21 proper gear 3c and to the countershaft 22 proper gear 3d meshes with the gear wheel 3e , the associated wave 13 transmits the rotation to the drive wheels.

1st gear works with the shift element closed to the right 37 about the gear pair 4.4 . 4a4 , 2nd gear with the shift element closed to the left 35 about the gear pair 3.2 . 3a2 , 3rd gear with the shift element closed to the left 37 about the gear pair 4.3 . 4a3 and 4th gear with the shift element closed to the right 35 about the gear pair 3.1 . 3a1 , These gears work over waves 21 , During the 5th, 6th and 7th gear over wave 22 work. 5th gear works with the shift element closed to the right 38 about the gear pair 4.2 . 4a2 , 6th gear with the shifting element closed 34a about the gear pair 3.1 . 3b1 and 7th gear with the shift element closed to the left 38 about the gear pair 4.1 . 4a1 , As is known, the two countershafts result in a shortened design and for two gears (here 4th and 6th gear) one drive gear is sufficient (here 3.1 ). Because the gears alternate over the waves 23 and 24 work and adjacent gears never have a common shift element, load shifts are always possible.

The reverse gear works with the shifting element closed 34b and switching element closed to the right 37 about the gear pair 3.1 , 3bl (6th gear), the gears 4b3 . 4a3 and 4.3 (Reversal of direction of rotation for shaft 24 ) and the gear pair 4.4 . 4a4 (1st gear). This process can also be seen as a group gear, but only a gear 4b3 and switching element 34b are necessary. It is also advantageous that the gears 4.3 and 4.4 cause the necessary reduction for the reverse gear and only the already heavily torque-loaded gear pair 4.4 . 4a4 is loaded with high torques. It is further advantageous that the 1st gear remains switched on for the reverse gear and the reverse gear via the shaft 23 works, (1st gear over wave 24 ), which enables "load shifts" between 1st and reverse gear.

It is necessary for this process that the switching element 34b a torsionally rigid connection between the gears 3b1 and 4b3 regardless of wave 22 is made possible (because wave 22 in reverse gear rotates counter to the gears 3b1 and 4b3). It is necessary that the gears 3b1 and 4b3 are arranged immediately adjacent.

If - as drawn - switching elements 34a and 34b the gear 3b1 are assigned, they can be designed as a switching element (with an actuating device), since a connection between the gearwheel shifted to the left as a whole 3b1 and wave 22 (6th gear) and altogether shifted to the right a connection between gears 3b1 and 4b3 (Reverse gear) is produced.

The central synchronization can be done with the switching element closed 36a (Synchronous element) evil the synchronous element 36 take place, the gears of the 2nd gear ( 3.2 ), 3rd course ( 4.3 ) and 4th course ( 3.1 ) to be used. As already described in the application 102 25 331.5, the smaller center distance between the shafts 50 and shafts 23/24 compared to the center distance between the shaft 21 and the waves 23/24 that the smaller gait jumps of the higher gears into larger gait jumps over wave 50 be implemented. With the drawn dimensions of the gears 3x1 and 4x3 and synchronizer element closed to the right 36 exists between the waves 23 and 24 a speed factor like the gear jump between 1st and 2nd gear. This is with the switching element closed to the right 36 wave 23 braked to shift up to 2nd gear or shaft 24 accelerates to downshift to 1st gear. In order to shift up to the higher even gears and to shift down into the higher odd gears, a synchronization can take place by means of controlled "synchronization". With the synchronizing element closed to the left can be reached via the gears 3x2 and 4x3 a speed factor between the shafts 23 and 24 , which is about 11% above the gear jump between 2nd and 3rd gear. This means that the upshift to the odd gear and the downshift into the even gears must always be carried out by "synchronizing". This is due to the fact that an odd and two adjacent even gears are used for the central synchronization (see also intermediate remarks and variant 2 ).

With this arrangement, the shaft rotates 50 mostly faster than waves 23/24, which is advantageous for the starter generator ( 60 ) can be. Basically, the synchronous element 36a omitted. With this element, however, is a much better speed adjustment of the starter generator 60 possible because the wave of the waves not used 23 and 24 brought to a desired speed via the countershaft transmission and via the synchronizing elements 36 and 36a the speed of shaft 50 can be adapted to an optimal speed for the starter generator in a wide speed range.

If wave 50 who have favourited Gears 3x2 and 4x3 and the associated synchronizing elements can be designed according to high torque, can by shaft 23 about the gear pairs 3.2 . 3x2 and 4x3 . 4.3 and further a crawl gear (eg for off-road vehicles) can be realized via the 1st gear, because the shaft 24 rotates accordingly slower (see also registration 102 25 331.5). Because of the large speed factor, this gear jump is also progressive. Power shifts are also possible between creeper and 1st gear. A gearbox designed in this way can therefore be modular for 7 preheat gears (with a "weak" shaft 50 ) and for 8 forward gears (with "strong" shaft 50 ) can be interpreted. However, generator operation is not possible when starting in crawl gear. 1b ) finally shows the spatial arrangement of the axes and where which gears mesh with each other.

interjections

When 1st, 2nd and 3rd gear (gears 4.4 . 3.2 and 4.3 in the variant 1 ) are used for the central synchronization, you have the same center distance from shafts 21 and 50 the right synchronization conditions for waves 23/24. Then the wave needed 50 but large gears and therefore rotates accordingly slowly, which can be unfavorable for the starter generator.

In the application 102 25 331.5 it has already been shown that a central synchronization is also possible with the 3rd, 4th and 5th gear, whereby shaft 50 turns much faster. (There is, however, due to slightly changed gear ratios, the center distance of the shaft 50 larger than here with the variant 2 .)

So that a central synchronization across the aisles 3 . 4 and 5 works properly, they must work on a countershaft (preferably shaft 21). This is with the variant 1 not the case (5th gear works via shaft 22 ). It is also beneficial if in each of the waves 21 and 22 two non-adjacent gears can be actuated with one switching element. The variant shows how these requirements can be met 2 shown. (In principle, central synchronization via completely different gears is also possible, via both shafts 21 and 22 can work. The only decisive factor is the diameter of the gear wheels on the shafts 23 and 24 , About the center distances from the shafts 23/24 to the shafts 21 and 22 and the diameter of the gears 3c and 3d there are many possible variations here.)

Va riante 2

In the 2a ) outlined variant 2 is also a 7-speed powershift transmission with progressive gear ratios in countershaft design with 2 countershafts 21 and 22 , The input waves 23 and 24 , Wave 50 , Component 60 , Gears 3c . 3d and 3e and wave 13 have the same functions as the variant 1 ,

The corridors work so that the requirements set out in the interim comments can be met 1 . 3 . 4 and 5 over wave 21 with gear 3c , the gears work accordingly 2 . 6 and ? over wave 22 with gear 3d , the reverse gear can from the switching element 34b be coupled with 7th gear, otherwise 1st and 4th gear, 2nd and 6th gear and 3rd and 5th gear are combined with one shift element each (so that no adjacent gears belong to one shift element). 1st gear works with the shift element closed to the right 35 about the gear pair 4.4 . 4a4 , 2nd gear with the shifting element closed 34a about the gear pair 3.2 . 3a2 , 3rd gear with the shift element closed to the left 37 about the gear pair 4.3 . 4a3 , 4th gear with the shift element closed to the left 35 about the gear pair 3.1 . 3a1 , 5th gear with the shift element closed to the right 37 about the gear pair 4.1 . 4a1 , 6th gear with the shifting element closed 38 about the gear pair 3.1 . 3b1 and 7th gear with the shifting element closed 34c about the gear pair 4.2 . 4a2 , Here, too, the 4th and 6th gear are geared 3.1 driven. (In principle, two other gears can also be driven with one gear.) The reverse gear works with the shifting element closed 34a and switching element closed to the right 35 by wave 23 forth over the gear pair 3.2 . 3a2 (2nd gear) and the gear pair 4b4 . 4a4 (Speed reversal) on shaft 21 , the gear 4a4 belongs to 1st gear and 1st gear remains engaged for reverse gear. Therefore, "power shift" between 1st and reverse gear is also possible here, since these two gears with unchanged positions of the switching elements over the waves 23 (Reverse gear) and 24 (1st gear) work. Compared to the variant 1 there are fewer gears involved in reverse here, but the gear is for that 4b4 but quite big and this gear and the switching element 34b have to transmit the high torques of the 2nd gear. About the diameter of the gear 4b4 the ratio of the reverse gear can be varied within wide limits (with the dimensions shown, the reverse gear is slightly faster than the 1st gear in both variants).

The switching elements 38 and 34a can be combined into a normal double-acting switching element, switching element 34b and 34e can be axially coupled (one actuating device), but must be able to turn against each other (the coupled switching elements 34a and, 34b of the variant 1 need a turn to the shaft 22 allow).

Basically, the gear 4b4 also omitted. Then the gears 3.1 and 3.2 with the associated gears ( 2 , and 4th gear) swap places. Then if gear continues 4a2 (for 7th gear) is designed as a sliding wheel, the reverse gear can be shifted to the left and with a gear 4a3 meshing gear 4a2 work when the gear 4a2 in this position also with the gear 3b1 torsionally rigid coupling (in principle, the torque transmission is then the same as for the variant 1 ). The positions of the gear 4a2 :

• - shifted to the left and directly (via a claw coupling) with gear 3b1 coupled for reverse gear
• - partially in the middle with the gear 4.2 combing but not yet with the wave 22 coupled, for the forward gears without the 7th gear (switching at a standstill between forward and reverse gear)
• - shifted to the right, full of gear 4.2 intermeshing and (via a claw coupling) with shaft 22 coupled for 7th gear.

So a sliding wheel with the associated Claw couplings for 7th gear and reverse gear responsible be (without associated drawing).

For the central synchronization can synchronous element 36a basically omitted (this element has the same meaning here as for the variant 1 ). If gear 3x1 rotatable with shaft 50 connected and synchronous element 36 closed to the left exists between the waves 23 and 24 a speed factor such as the speed jump between 1st and 2nd gear (with the dimensions shown), this serves to synchronize the upshifts in even gears and the downshifts in odd gears. With the synchronizing element closed to the right 36 exists between the waves 23 and 24 a speed factor like the gear jump between 2nd and 3rd gear, this serves to synchronize the upshifts in odd gears and the downshifts in even gears.

Compared to the variant 1 here the synchronization processes are better adapted and the speed level of the shaft 50 is higher overall. As described, the gear 4b4 also dropped. Here too is about the gears 3x1 and 4x1 a creeper possible. However, the gear jump between crawl gear and 1st gear is the same as the gear jump between 2nd and 3rd gear.

2 B ) finally shows the spatial arrangement of the axes and where which gears mesh with each other.

Concluding remarks, advantages the invention

In principle, the gearwheel can also be used in variant 1 463 omitted if the gear 4a1 is converted into a sliding wheel and then has the same functions as the sliding wheel 4a2 in the description of the variant 2 , (The torque vectors for forward and reverse gear operation of the sliding wheel are opposite. Helical-toothed sliding wheels can therefore be designed so that they are pressed against the respective limit by the driving forces.) The reverse gears all work from the last (right) gear wheel of the shaft 23 on a the wave 22 assigned and with the last gear of the shaft 23 meshing gear, from there on to another gear immediately adjacent to the right, these two adjacent to the shaft 22 assigned gears for reverse gear regardless of shaft 22 be connected to one another in a rotationally fixed manner. The right of the two gears connected in a rotationally fixed manner meshes with a gear of the shaft 21 , If this gear is the shaft 21 is a gear of the 1st gear, this gear is in reverse gear via the switching element of the 1st gear with shaft 21 connected and the torque is transmitted directly via this gear (e.g. 2 ). If this gear is the shaft 21 is not a 1st gear, it will not be with the shaft 21 connected and the torque transmission continues via the shaft 24 to the gear pair of the 1st gear and from there to the shaft 21 (eg l ). In all cases, the shafts rotate 24 and 21 (and about the gear pair 3e . 3d also wave 22 ) backwards. The gearwheel for torque transmission from the shaft 22 to the wave 21 in reverse gear can also be designed as a sliding wheel (and, for example, a gear of the 7th gear at the same time). (Of course, the arrangement of the gears can also be reversed, for example, in mirror image.) It is advantageous that there is no need for an additional shaft for the reverse gear (shaft 22 is used) and that only a maximum of one additional gear (or a sliding wheel) must be available for reverse gear. This is achieved by the last (right) gear of the straight gears of the shaft 22 is assigned and the first (left) gear of the odd gears of the shaft 21 that on the wave 22 torque transmission independent of shaft 22 to one with the left gear of the shaft 21 meshing gear and that these two gears reverse the speed.

It is also advantageous that the reverse gear on the shaft 21 is transmitted with the gear and shifting element of the 1st gear. This transmission path must be designed for high torques anyway. And so, without further switching operations, by alternately driving the shafts 23 and 24 toggle between 1st gear and reverse gear. (Before changing to 2nd gear, reverse gear must be switched off, however.)

Compared to application 102 25 331.5, an extra pair of gears is provided for 1st gear (in the above application, 1st gear works via the gear pair of 2nd gear). Connected to this pair of gears for 1st gear are the advantages for reverse gear described above. On the other hand, the starter generator (in stop and go traffic) 60 ) from the wave 23 are driven here (even when 1st gear is engaged and the associated clutch is open), which results in favorable generator operation in all operating states, in particular when the synchronizing element is installed 36a , Of course, the transmission can also be switched into a favorable ratio for starter operation for different conditions.

About wave 50 if additional gears (e.g. a creeper gear) are possible, then generator operation is restricted.

If each of the two waves 21 and 22 has a maximum of 2 double-acting switching elements (with 7 + 1 gears), these switching elements can move from the ends of the shafts 21 and 22 be operated from the inside of these waves.

Claims (9)

Reverse gear for powershift transmission with two input shafts 23 and 24 , two countershafts 21 and 22 with associated output gears 3c and 3d , characterized in that the shaft 21 1st gear (and preferably low gears) and the wave 22 At least one straight (and preferably high gears) are assigned to this straight gear of the shaft 22 inside the gearbox in the transition area between the shaft 23 and 24 the shaft with the straight gears (here shaft 23 ) is assigned to that on the shaft 22 another gear is attached directly adjacent to this gear or can be moved into this position and with a gear for odd gears of the shaft 21 combs or meshes with this gear in the shifted state and a rotationally fixed connection between this gear and the gear of the immediately adjacent straight gear regardless of the shaft 22 can be manufactured. Powershift transmission according to claim 1, characterized in that said shaft 22 independent rotatable connection between gears 3b1 and 4b3 via a switching element 34b takes place and this switching element 34b with a switching element 34a can be coupled and via these switching elements 34a and 34b the gear 3b1 (as idler gear of the shaft 22 ) either with wave 22 can be rotatably connected (e.g. for 6th gear) or can be released or with the gear 4b3 can be rotatably connected (for reverse gear) (variant 1 ) or that this from wave 22 independent non-rotatable connection of gear 3a2 and gear 4b4 via a switching element 34b takes place and that this switching element 34 for axial displacements but otherwise rotatable with a switching element 34c can be coupled. Power shift transmission according to at least one of claims 1 and 2, characterized in that a gear 4a1 (Variant 1) or 4a2 (variant 2) is axially displaceable so that either the gear 4a1 in one with the gear 4.1 or the gear 4a2 in one with the gear 4.2 combing position can be moved and in this position with shaft 22 For example, the cogwheel can be connected in a rotationally fixed manner via a claw coupling or a switching element 4a1 or 4a2 in one with a gear 4a3 combing position can be brought and in this position a shaft 22 independent non-rotatable connection between gear 4a1 or 4a2 and gear 3b1 can be manufactured. Power shift transmission according to claim 3, characterized in that sliding gears 4a1 or 4a2 are so helically toothed that the gear wheels 4al and 4a2 are pressed in their respective end positions in drive operation against the respective stop. Power shift transmission according to at least one of claims 1 to 4, characterized in that the gear 4a4 for reverse gear via switching element 35 rotatable with shaft 21 is connected and thus the reverse gear directly from the gear 4b4 on the gear of the 1st gear 4a4 is transferred (variant 2 ). Power shift transmission according to at least one of claims 1 to 4, characterized in that the gear 4b3 with the gear 4a3 combs (variant 1 without sliding wheel) or that the gear 4a1 or 4a2 (Variant 1 or variant 2 with sliding wheel) in one with the gear 4a3 combing position can be brought up that gear 4a3 not with wave 21 rotatably connected that with a gear 4.3 meshing gear 4a3 the one with gear 4.3 firmly connected shaft 24 drives backwards and that from wave 24 forth about a pair of gears 4.4 . 4a4 (otherwise responsible for 1st gear) and one to the gear 4a4 closed switching element 37 a non-rotatable connection to the shaft 21 is produced and so the reverse gear is transmitted. Power shift transmission according to at least one of claims 1 to 6, characterized in that each of the shafts 21 and 22 is equipped with a maximum of 2 double-acting switching elements. Central synchronization for powershift transmissions with two input shafts 23 and 24 , two countershafts 21 and 22 and a secondary wave 50 , characterized in that either the gears of the 2nd, 3rd and 4th gear of a countershaft (variant 1 , here wave 21 ) or the 3rd, 4th and 5th gear wheels of a countershaft (variant 2 , here also wave 21 ) that are assigned to gears 3.1 . 3.2 and 4.3 with one each to the shaft 50 proper gear 3x1 . 3x2 and 4x3 comb that at least the gears 3x1 and 3x2 are designed as idler gears and via a double-acting synchronizing element 36 with wave 50 can be connected to that optionally also gear 4x3 via a synchronous element 36a by wave 50 can be solved and that the distance between shaft 50 and the waves 23/24 is chosen so that between the waves 23 and 24 over the wave 50 a speed factor can be achieved that corresponds at least to the gear jump between 1st and 2nd gear (variant 1 ) or that the gears 3.1 . 4.1 and 4.3 with one each to the shaft 50 proper gear 3x1 . 4x1 and 4x3 comb that at least the gears 4x1 and 4x3 are designed as idler gears and via a double-acting synchronizing element 36 with wave 50 can be connected to that optionally also gear 3x1 via a synchronous element 36a by wave 50 can be solved and that the distance between shaft 50 and the waves 23/24 is chosen so that between the waves 23 and 24 over the wave 50 a speed factor can be achieved that corresponds at least to the gear jump between 2nd and 3rd gear (variant 2 ) and that with the wave 50 a starter generator connected directly or via a component 60 can be connected. Central synchronization for powershift transmissions with two input shafts 23 and 24 , two countershafts 21 and 22 with associated output gears 3c and 3d and a secondary wave 50 , characterized in that the center distances between the shafts 21 respectively. 22 and shafts 23/24, the diameter of the gears 3e and 3d and a gear pair with a common gear for the shafts 21 and 22 be chosen so that the requirements in claim 8 for the speed factors between shafts 23 and 24 over wave 50 approximately also be met via gears that are not just one of the waves 21 or 22 assigned.