WO2002077489A1

WO2002077489A1 - Vehicle transmission

Info

Publication number: WO2002077489A1
Application number: PCT/EP2002/002984
Authority: WO
Inventors: Jürgen WAFZIG
Original assignee: Zf Friedrichshafen Ag
Priority date: 2001-03-24
Filing date: 2002-03-19
Publication date: 2002-10-03
Also published as: DE10114557A1

Abstract

The invention relates to a vehicle transmission provided in a group design comprising an input shaft (8), an output shaft (9) that is arranged coaxial to the input shaft (8), and a countershaft (10) that is provided parallel to said input and output shafts. A two-speed additional transmission group (26) having two gear sets (IV, V) is connected up from or down from a main transmission group (25) having a number of gear sets (I to III and W) that can be manually shifted, and gear sets (W and I to V) each have a fixed gear (11 to 16) and an idler gear (17 to 22). The invention provides that: the main transmission group (25) comprises three gear sets (I to III) for six forward speeds (1 to 6) and a reversing gear set (W) for a reverse speed; the idler gears (17 to 22) of all gear sets (W and I to V) as well as associated clutches (a to e and g) are arranged on the countershaft (10); a seventh speed (7) is shifted as a direct speed by a clutch (f) that, in the shifted state, directly connects the input shaft (8) to the output shaft (9), and; a gear step (f) between the sixth speed (6) and the seventh speed (7) is less than the gear steps between the remaining forward speeds (1 to 6).

Description

vehicle transmissions

The invention relates to a vehicle transmission according to the preamble of claim 1.

Vehicle gearboxes in countershaft design are a very cheap gearbox solution in terms of design and especially considering the price. As a rule, they each have an input shaft and an output shaft, as well as a countershaft arranged parallel to these. The power flow flows via a gear set from the drive shaft to the countershaft and from there via a further gear set to the output shaft. One of the wheel sets, which is involved in all gears and is called a constant, has two fixed gears that mesh with one another and are each seated on the countershaft or the input shaft or the output shaft. The other wheel set has an idler gear and a fixed gear. It is assigned to a gear. The gear set for reverse gear, also called turning gear set, also has an idler gear which meshes with the idler gear on the one hand and with the fixed gear on the other and reverses the direction of rotation of the output shaft with respect to the drive shaft.

In order to reduce the masses to be synchronized in a gearshift, the fixed gears for the forward gears and the reverse gear are usually seated on the countershaft, while the idler gears are rotatably mounted on the drive shaft or output shaft and are coupled to the respective shaft by means of clutch clutches can. Vehicle transmissions of this type require a wheel set for each gear which has a transmission ratio which differs from one. For direct drive through the gearbox, which corresponds to a ratio of one, the drive shaft is coupled directly to the output shaft via a clutch without torque being transmitted via wheel sets. 5 A vehicle transmission with six forward gears, one of which is designed as a direct gear, and one reverse gear needs six gear sets and seven clutches. The clutches are usually arranged in the vehicle transmission in such a way that they are mechanically actuated.

L0 lung elements can be operated by the driver in succession by operating a shift lever in two mutually perpendicular movement levels. Movement in the first movement level selects two gears of a shift gate and movement in the second

L5 direction of movement is one of the selected gears.

There is known a six-speed transmission in the preliminary design for trucks, construction books volume 26, Johan-

20 nes Looman, gear transmission, 1970 Springer-Verlag Berlin, page 4, in which a constant gear set is arranged on the drive side of the transmission. The fixed wheel of this wheel set, which sits on the drive shaft, can be coupled to the output shaft via a clutch.

25 is connected directly to the drive shaft by the output shaft and thus forms a direct sixth gear. The idler wheels of the wheel sets are mounted on the output shaft and are optionally coupled to it by means of clutch clutches. The turning gear set for reverse gear is on

30 the output side of the transmission. Such a transmission requires only five wheel sets for six forward gears. The wheel sets and the clutch clutches are arranged so that the clutch for the turning wheel set in a first lane, the clutches for the first and second wheelsets in a second lane, the clutches for the third and fourth wheelsets in a third lane and the clutches for fifth and sixth gears in a fourth lane, so that the associated gears by a mechanical Manual switching with a logical circuit diagram can be switched in succession.

In order to be able to operate a vehicle engine while driving in the optimum operating range, gearboxes with many gears are desirable, the step changes between the individual gears increasing progressively from the highest gear to the lowest gear. This ensures that the driver can fine-tune the speed of the vehicle engine to the vehicle speed by means of a fine gradation. Furthermore, the entire gear ratio range of the vehicle transmission between the first and highest gear should be large, the ratio of the gear ratio area to the number of gears being relatively large and the construction effort being kept low. Such vehicle transmissions can be carried out with up to six forward gears at a reasonable cost.

The construction effort of a vehicle transmission can be reduced by using several wheel sets several times by using them to form different gears. For example, in the case of group transmissions of a main transmission group, an additional transmission group, consisting of two or more gear sets, is connected upstream and / or downstream, so that the combination of the gear sets of the auxiliary transmission groups with the wheel sets of the main transmission group results in the number of gears of the vehicle transmission from the product of Number of gears of the individual gear groups results. The increments between the wheelsets of the auxiliary transmission group are matched to the increments between the wheelsets of the main transmission group in such a way that a usable gradation of the vehicle transmission results overall. Due to the group structure of the vehicle transmission, only a geometrical and not a progressive gradation of the entire transmission range is generally possible, since the step changes of the main transmission group recur several times due to the multiple use of the wheel sets of the main transmission group.

The additional transmission group is usually designed so that it divides the increments of the main transmission group as a so-called split transmission group or extends the transmission range of the main transmission group upwards or downwards as a so-called range transmission group. While the main transmission group is usually designed in such a way that it can be shifted mechanically by hand, the additional transmission group is operated by external force, e.g. operated electrically, hydraulically or pneumatically. Group transmissions of this type are known from “Construction Books”, volume 26, pages 181 ff., Above, for transmissions with eight or more gears.

From DE 42 05 670 Cl a six-speed vehicle transmission in countershaft construction is also known, in which a total of six forward gears, including a direct gear, and a reverse gear are realized with five gear sets. This happens because a medium wheel set is used several times, in that it can be assigned to the drive shaft and the output shaft via shift clutches. The number of gears can be increased by two gears using an additional set of wheels. be raised. Winding gears of this type can no longer be switched in a logical circuit diagram using conventional mechanical manual switching devices. However, this is not an obstacle since the clutches can be actuated by external forces.

The invention has for its object to provide a vehicle transmission in countershaft construction with a mechanical manual transmission for light commercial vehicles and a large translation range with little

To reach wheel sets. It is solved according to the invention by the features of claim 1. Further refinements result from the subclaims.

According to the invention, the main transmission group has three gear sets for six forward gears and one turning gear set for one reverse gear. The idler gears of all wheel sets and the associated clutches are arranged on the countershaft. A seventh gear is shifted as a direct gear by means of a clutch, which in the switched state connects the drive shaft directly to the output shaft. Finally, there is a step change between the sixth and seventh gear, which is smaller than the step jumps between the other forward gears.

Such a vehicle transmission is particularly suitable for large passenger cars and light commercial vehicles. Despite its seven gears, it is easy to shift because only the main transmission group is shifted mechanically by hand, while the additional transmission group is shifted by external power. This can be done, for example, electrically, hydraulically or pneumatically, the stage of the additional gear being selected with a switch by actuating one Clutch is switched. This results in a simple circuit diagram with short switching paths.

Due to the seven forward gears, a large overall ratio can be achieved, which nevertheless has relatively small increments. It is a particular advantage that the increment between the sixth and seventh gear is smaller than the increment between the other forward gears, so that the engine speed can be adapted well to the driving speed in the most frequently used driving range.

The additional transmission group can be designed as a range transmission group or as a split transmission group. In the first case, the first wheel set expediently has one

Gear ratio of 0.3, the second gear set of 0.44, the third gear set of 0.63 and the turning gear set a gear ratio of 0.33. These wheelsets form the main transmission group, while a fourth wheelset with a gear ratio of 2.70 and a fifth wheelset with a gear ratio of 0.89 form an upstream auxiliary gear group. The first to third wheelsets in conjunction with the fourth wheelsets form gears 1 to 3, while by switching to the fifth wheelset in conjunction with the first to third wheelsets gears 4 to 6 can be shifted.

If the additional transmission group is upstream of the main transmission group as a split transmission group, the ratios of the first gear set 0.33, the second gear set 0.69, the third gear set 1.46, the fourth gear set 2.97, the fifth gear set 2.05 and the turning gear set 0.36 are expedient. The fourth and fifth wheelset form the split gear group, with the fourth wheel set in connection with the first to third gear sets forms gears 1, 3 and 5, while the fifth gear set in conjunction with the 1st to 3rd gear sets forms gears 2, 4 and 6. The gear ratios chosen result in increments of approximately 1.45 between the first six forward gears, while the increment between the sixth and seventh gears is 1.40.

Further advantages result from the following description of the drawing. Exemplary embodiments of the invention are shown in the drawing. The description and claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into useful further combinations. Show it:

Fig. 1 is a transmission diagram of an inventive

Vehicle transmission, F Fiigg .. 2 2 a tabular compilation of individual translations of wheelsets,

Fig. 3 shows a circuit diagram for a vehicle transmission according to FIG. 1,

Fig. 4 shows a tabular shift logic for a transmission according to FIGS. 1 and 2,

Fig. 5 shows a variant of FIG. 2,

Fig. 6 shows a variant of FIG. 3,

Fig. 7 shows a variant of FIG. 4,

Fig. 8 a variant of Fig. 1, F Fiigg .. 9 9 another variant of Fig. 2 and

Fig. 10 a further variant of FIG. 3. The vehicle transmission according to FIG. 1 has an input shaft 8 and an output shaft 9 arranged coaxially thereto. A countershaft 10 is mounted parallel to both in a transmission housing (not shown). The bearings of the shafts 8, 9, 10 are designated by 24. The vehicle transmission also has a total of six wheel sets I to V and W. The wheel sets I to V and W have fixed wheels 11 to 16, which in the embodiments according to FIGS. 1 and 8 sit on the drive shaft 8 and on the output shaft 9, respectively constantly mesh with idler gears 17 to 22, which are mounted on the countershaft 10 and can optionally be coupled to the countershaft 10 via clutches a to e and g. The wheel set W is a turning wheel set which, in order to reverse the direction of rotation of the output shaft 9 in reverse gear R, has an intermediate gear 23 which meshes with the fixed gear 16 and the idler gear 22.

The gear sets I, II, III and W form a main gear group 25, while the gear sets IV and V belong to an auxiliary gear group 26. In the embodiment according to FIG. 1, the additional transmission group 26 is connected upstream of the main transmission group 25, so that its fixed gears 14 and 15 are seated on the drive shaft 8, while the fixed gears 11, 12, 13, 16 of the main transmission group 25 are assigned to the output shaft 9. The additional transmission group 26 can be designed as a range transmission group. In this case, the wheel sets I to V and W have the gear ratios i shown in FIG. 2, where i represents the gear ratio of the respective fixed gear 11 to 16 to the respective idler gear 17 to 22. The shifting logic shown in FIG. 4 shows that, for shifting the first three gears 1 to 3, the fourth gear set IV of the additional transmission group 26 is shifted by the clutch d and in first gear 1 the first wheel set I through the clutch a, in the second gear the second gear set II through the clutch b and in third gear 3 the third gear III through the clutch c with the countershaft 10 are successively coupled. To shift the three further forward gears 4, 5, 6, the fifth wheel set V is shifted by the clutch e, while the clutches a, b, c are operated in the same order for actuating the fourth to sixth gears 4 to 6 as for shifting the first to third gears 1 to 3. A sixth clutch f switches a seventh gear 7 as a direct gear by connecting the drive shaft 8 to the output shaft 9. A reverse gear R is engaged when the fifth gear set V is engaged by the clutch e and the turning gear set W by the seventh clutch g.

Together with the individual translations i according to FIG. 2, the translations u of the individual gears 1 to 7 and R result in accordance with the penultimate column in FIG. 4. This shows that in the first gear 1 there is a largest translation of nine, which in Step jumps φ corresponding to the last column in FIG. 4 drop to one in seventh gear 7. It should be noted that the step jump φ between the sixth and seventh gear 6, 7 is advantageously the smallest step jump φ and that the step jump φ between the fifth and sixth gear 5, 6 is still relatively small as the second smallest step jump φ. Thus, between the fifth and seventh gears 5, 7, the driver has a finely graded vehicle transmission available, through which the engine speed can be well adapted to the driving speed in the main driving range. 1 and 3, the first clutch a and the seventh clutch g for reverse gear R are in a first shift gate 27, the second clutch b and the third clutch c in a second shift gate 28 and the sixth clutch f arranged for the seventh gear 7 in a third shift gate 29. The shifting device, not shown, is expediently designed such that reverse gear R, second and fifth gear 2, 5 and seventh gear 7 are shifted in the direction of travel 30 according to the circuit diagram in FIG. 3. Naturally, the other gears 1, 3, 4, 6 are shifted in the opposite direction. The result is a simple, proven circuit diagram that does not take getting used to.

If the additional transmission group 26 is designed as a split transmission group, the gear sets I to V and W expediently receive the individual gear ratios i according to FIG. 5. Together with the shifting logic according to FIG. 7, it follows that the additional gear 26 makes the step change between the first gear set I and the second gear set II or between the second gear set II and the third gear set III or between the third gear set III and the drive in the seventh gear 7, with a step change of 1.4 remaining between the sixth gear 6 and the seventh gear 7 , Here, too, a greatest transmission ratio u is reached in first gear 1 with 9.00, which drops to one in seventh gear 7 according to the penultimate column in FIG. 7. The step jumps φ according to the last column are essentially equal to 1.45, while the step jump φ between the sixth gear 6 and the seventh gear 7 is 1.40 the smallest step jump φ. Corresponding to the different design of the additional transmission group 26, there is a changed circuit diagram in FIG. 6 compared to that in FIG. 3 6, the reverse gear R, the third gear 3, the fourth gear 4 and the seventh gear 7 are switched in the direction of travel 30, while the other gears 1, 2, 5, 6 are switched in the opposite direction.

Fig. 8 shows an embodiment in which the auxiliary transmission group 26 is connected downstream of the main transmission group 25. Correspondingly, the fixed wheels 11 to 13 and 16 of the wheel sets I, II, III and W are located on the drive shaft 8, while the fixed wheels 14 and 15 of the wheel sets IV and V are arranged on the output shaft 9.

In FIG. 9, individual gear ratios i for the wheel sets I to V and W according to FIG. 8 are given. The translations i of the wheel sets IV and V show that the additional transmission group 26 is designed as a split transmission group and has the shifting logic shown in FIG. 10. The switching logic essentially corresponds to the switching logic according to FIG. 7.

The step changes φ are also the same, the gear ratios u differing slightly in the individual gears. The rotating masses to be synchronized are relatively low. Furthermore, there is no gear ratio between the switching elements a to g and the rotating masses to be synchronized which could increase the rotating mass. This results in the switching of the

Main gearbox group 25 low shifting forces, which enable short shifting distances. Since the shift clutches a, b, c, f and g are arranged in the same lanes 27, 28, 29, the same shift pattern as in FIG. 6 can be generated. reference numeral

1 first gear 28 second shift gate

2 second gear 29 third shift gate

3 third gear 30 driving direction

4 fourth gear

5 fifth gear I wheelset

6 sixth gear II wheelset

7 seventh gear III wheelset

8 drive shaft IV wheelset

9 Output shaft V wheel set

10 countershaft W wheelset

11 first fixed gear R reverse gear

12 second fixed gear a first clutch

13 third fixed gear b second clutch

14 fourth fixed gear c third clutch

15 fifth fixed gear d fourth clutch

16 sixth fixed gear e fifth clutch

17 first idler gear f sixth clutch

18 second idler gear g seventh clutch

19 third idler gear

20 fourth idler gear u gear ratio

21 fifth idler gear φ increment

22 sixth idler gear i translation

23 idler gear

24 bearings

25 main transmission group

26 Additional gear group

27 first shift gate

Claims

Patent claims

1. Vehicle transmission in a group construction with an input shaft (8), an output shaft (9) arranged coaxially to the input shaft (8) and a countershaft (10) provided parallel to both, whereby a main transmission group (25) with several manually switchable gear sets (I to III and W) a two-speed auxiliary transmission group (26) with two gear sets (IV, V) is connected upstream or downstream and the gear sets (W and I to V) each have a fixed gear (11 to 16) and an idler gear (17 to 22) , characterized in that the main transmission group (25) has three gear sets (I to III) for six forward gears (1 to 6) and a turning gear set (W) for a reverse gear, that the idler gears (17 to 22) of all gear sets (W and I to V) and associated shift clutches (a to e and g) are arranged on the countershaft (10) such that a seventh gear (7) is shifted as a direct gear by means of a shift clutch (f) which, in the shifted state, drives the drive shaft ( 8) di connects directly to the output shaft (9) and that a step change (φ) between the sixth gear (6) and the seventh gear (7) is smaller than the step jumps between the other forward gears (1 to 6).

2. Vehicle transmission according to claim 1, characterized in that the additional transmission group (26) is connected upstream of the main transmission group (25) and the wheel sets (W and I to V) from their fixed wheels (11 to 16) to their associated idler wheels (17 to 22) have the following translations (i): the first wheel set (I) 0.3, the second wheel set (II) 0.44, the third wheel set (III) 0.63, the fourth wheel set (IV) 2.70, - the fifth wheel set (V) 0.89 and the turning wheel set (W) 0.33.

3. Vehicle transmission according to claim 1, characterized in that the additional transmission group (26) is connected upstream of the main transmission group (25) and the wheel sets (W and I to V) from their fixed wheels (11 to 16) to their associated idler wheels (17 to 22) have the following gear ratios (i): the first gear set (I) 0.33, - the second gear set (II) 0.69, the third gear set (III) 1.46, the fourth gear set (IV) 2.97, the fifth gear set (V) 2.05 and the turning wheel set (W) 0.36.

4. Vehicle transmission according to claim 1, characterized in that the additional transmission group (26) is connected downstream of the main transmission group (25) and the wheel sets (W and I to V) from their fixed wheels (11 to 16) to their associated idler wheels (17 to 22) have the following gear ratios (i): the first gear set (I) 3.39, the second gear set (II) 1.61, the third gear set (III) 0.76, - the fourth gear set (IV) 0.38, the fifth gear set (V) 0.55 and the Turning wheel set (W) 3.13.

5. Vehicle transmission according to one of the preceding claims, characterized in that the first and seventh clutch (a and g) for the first gear set (I) and the turning gear set (W) in a first shift gate (27), the second and third clutch ( b and c) for the second and third gear set (II and III) in a second shift gate (28) and the sixth clutch (f) for coupling the drive shaft (8) with the output shaft (9) in a third shift gate (29) are arranged.

6. Vehicle transmission according to claim 5, characterized in that a shift lever for shifting the gears (R and 1 to 7) for the reverse gear (R) and for the second, fifth and seventh gear (2, 5, 7) in the direction of travel (30 ) is moved.

7. Vehicle transmission according to claim 5, characterized in that a shift lever for shifting the gears (R and 1 to 7) for the reverse gear (R) and for the third, fourth and seventh gear (3, 4, 7) in the direction of travel (30) is moved.