EP1938002A1

EP1938002A1 - Automatic transmission and shift control method for said transmission

Info

Publication number: EP1938002A1
Application number: EP06805865A
Authority: EP
Inventors: Karl-Fritz Heinzelmann
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2005-10-19
Filing date: 2006-09-26
Publication date: 2008-07-02
Also published as: DE102005050067A1; JP2009511843A; CN101292101A; KR20080058388A; RU2008119408A; US20080245168A1; BRPI0617736A2; WO2007045333A1

Abstract

The invention relates to an automatic transmission of a motor vehicle, comprising an input shaft, an output shaft, arranged coaxially to the input shaft, and a plurality of gears that can be selectively shifted via clutches associated therewith. The input shaft is connected to a driving engine via an engine clutch that can be engaged and disengaged. An additional controlled friction clutch is provided as the powershift clutch for optionally bridging at least one of the clutches. The aim of the invention is to improve a transmission of the aforementioned kind with regard to its performance and for retrofitting an existing transmission. According to the invention, the powershift clutch (K') is effective directly between the driving engine (M) and the output shaft (W2 or W5). For this purpose, the powershift clutch (K') is arranged on the input end of the clutch (1, 1') in coaxial relation to the engine clutch (K). The gear shafts (W1 or W1, W2, W4) arranged axially between the powershift clutch (K') and the output shaft (W2 or W5) are configured as hollow shafts. The output shaft (W2 or W5) is extended within said gear shafts (W1 or W1, W2, W4) up to the part of the powershift clutch (K') on the transmission end.

Description

Automated transmission and method for Schaltsteuerunq such a gearbox

The invention relates to an automated manual transmission of a motor vehicle, having an input shaft, with a coaxially arranged to the input shaft output shaft and a plurality of selectively shiftable gears via associated clutches, wherein the input shaft is connected via an engageable and disengageable engine clutch with a drive motor, and a additional controllable friction clutch is provided as a power-shift clutch for on-demand bridging at least one of the clutches.

The invention further relates to a method for switching control of an automated manual transmission of a motor vehicle having an input shaft, a coaxially arranged to the input shaft output shaft and a plurality of selectively shiftable gears via associated clutches, and wherein the input shaft via an engageable and disengageable engine clutch with a Drive motor is connected, wherein during a switching operation, an additional controllable friction clutch is closed as a power-shift clutch for bridging the clutches involved in the switching process.

Automated manual transmissions are increasingly used in motor vehicles both in passenger vehicles and in the commercial vehicle sector, since they have a high level of operating convenience with relatively low weight, compact dimensions and a high degree of transmission efficiency due to the automatically running gearshifts, and enable low fuel consumption of the motor vehicles in question. A disadvantage of automated manual transmissions, however, is the design-related interruption of the power flow between the drive motor and the output shaft. limited final drive during a gear change, which is caused by the fact that the engine clutch is temporarily open and the transmission is temporarily idle. In this way, an undesired acceleration of the motor vehicle may occur during an upshift, in particular during an upshift during the passage of a gradient, an undesired deceleration of the motor vehicle, and during a downshift, in particular during a push-down during the passage of a gradient. This generally leads to a delay and to an uncomfortable sequence of the switching operation.

It is therefore particularly known in commercial vehicles to accelerate the synchronization of the gear to be engaged in an upshift by a transmission brake or assist in closed engine clutch by engaging in the engine control and optionally in upshifts by means of a motor brake in shifts to shorten the power interruption, which, however associated with additional expenses for the ancillary equipment.

The present invention therefore relates both to simple automatic gearboxes in countershaft design or in planetary design with claw clutches, which are mainly used in passenger cars and light vans, as well as so-called group transmissions consisting of several serially coupled sub-transmissions and mainly in heavier commercial vehicles for use come. Such a group transmission is known for example from DE 100 51 354 A1 in the form of a range group transmission, which consists of a simple main gear in Vorgelegebauweise and this downstream range group in planetary construction.

To avoid an interruption of traction during a shift, an automated transmission can be known with an additional chen controllable friction clutch be provided, through which the input shaft of the transmission is connectable to the output shaft during a switching operation. Thus, a gear change can be performed as a load circuit without interruption of traction or at least as a partial load circuit with reduced torque transmission.

Such an automated manual transmission is described in DE 198 59 458 A1, which is a gearbox in countershaft design and acting as a power-shift clutch additional friction clutch parallel to the clutch of a gear gear, preferably on the idler gear of the highest gear, is arranged. A disadvantage ah this gearbox is the arrangement of the additional clutch within the gearbox, as a result, an appropriate retrofitting of an existing gearbox for reasons of space either not at all possible or can only be realized with major changes. Furthermore, the arrangement of the additional friction clutch requires that the engine clutch remain closed during the shift, which makes the design of the load gear and the synchronization and engagement of the target gear at least difficult.

Against this background, the present invention seeks to propose a functionally and in terms of retrofitting an existing gearbox more favorable arrangement of a power-shift clutch on an automated transmission of the type mentioned. Furthermore, a method for switching control of such an automated manual transmission should be specified.

The solution of the problem relating to the manual transmission in conjunction with the features of the preamble of claim 1 is that the power shift clutch is effective directly between the drive motor and the output shaft by the load clutch on the input side of the gearbox is arranged coaxially with the engine clutch by the axially located between the power shift clutch and the output shaft transmission shafts are formed as hollow shafts, and in that the output shaft is extended within these transmission shafts to the transmission-side part of the power shift clutch.

As a result, by closing the power shift clutch, both the engine clutch and all the clutches of the transmission are bridged, whereby switching operations with open and closed engine clutch are possible.

Furthermore, the power-shift clutch can be arranged in the proposed arrangement outside the gearbox of the gearbox, so that existing manual transmission with relatively little effort, namely with the replacement of the output shaft by a prolonged execution of the same and by replacing the coaxial transmission shafts through hollow shafts, to powershift transmissions can be upgraded.

Advantageous embodiments and further developments of the gearbox according to the invention are specified in the dependent claims 2 to 5.

The power-shift clutch can in principle be designed both as a dry clutch and as a hydrostatic multi-plate clutch. The design of the power-shift clutch is oriented expediently to the loads occurring during operation, in particular to the heat load, and on the design of the engine clutch, in the clutch housing, the power-shift clutch, in particular of the same design, is advantageously arranged to reduce the space requirement. In this sense, it is also advantageous if the power shift clutch and the engine clutch have a common clutch basket.

In a widespread embodiment of the gearbox as a simple countershaft transmission with an input shaft, a coaxial to arrange it Neten output shaft, and arranged with a parallel to these transmission shafts countershaft, the input shaft is thus formed as a hollow shaft and extends the output shaft of the gearbox within the input shaft to the transmission-side part of the power shift clutch. As a result, then all circuits within the gearbox by means of the power shift clutch as load circuits or partial load circuits are feasible.

Accordingly, in one embodiment of the gearbox as a group transmission with a main gear in a simple countershaft design and a downstream range group in planetary design, the input shaft and the output shaft of the main gear and the input shaft of the range group are formed as hollow shafts, and the output shaft of the range group, in this case, the output shaft of the forms entire shift transmission, is extended within the output shaft of the range group and within the output shaft and the input shaft of the main transmission to the transmission-side part of the power shift clutch. As a result, in addition to the circuits within the main transmission, the range circuits within the range group can also be implemented as load circuits or partial load circuits.

In addition to the above exemplary embodiments of manual transmissions, the arrangement according to the invention of a power shift clutch is applicable to all types of manual transmissions or group transmissions with coaxial input and output shafts.

The solution of the problem concerning the method of shift control in conjunction with the features of the preamble of claim 6 is that during a shift between two maximum one direct gear-containing gears (i> = 1) before laying out the load gear for torque transfer by an at least partially Close the power shift clutch a direct connection between the drive motor and the output output shaft is made, then the load gear is designed, then the target gear is synchronized and engaged, and finally the power shift clutch is fully opened again.

By at least partially closing the power-shift clutch, the torque transmitted by the drive motor via the engine clutch to the input shaft is largely taken over. As a result, the clutch of the loaded load gear is relieved and can thus be opened to load the load largely free of load. Likewise, the target gear to be engaged can be largely synchronized without load and subsequently loaded.

By means of the arrangement according to the invention of the powershift clutch, the shifting operations, insofar as they do not include an overdrive gear (i <1), can thus be carried out without interruption of the power flow as a partial load shift. As a result, an undesirable deceleration or acceleration of the motor vehicle is avoided, so that the switching operations can be faster and more comfortable as a whole. Due to the load voltage maintained in the drive train, load surges and vibrations are avoided, which is associated with reduced wear on critical parts of the powertrain and an overall higher ride comfort. Other, provided for switching operations to reduce the input speed of the gearbox devices, such as a transmission brake or an engine brake, can be eliminated or saved.

During the switching operations, the power-shift clutch is almost always controlled in the slip state due to the compared to the effective translation of the load gear mostly more direct translation. An exception to this is only a switching operation from the direct gear (i = 1) to a smaller gear (i> 1), in which the load-shifting clutch for taking over the torque can be completely closed, at least temporarily. If a switching operation is performed with the engine clutch open, so the engine clutch is opened before laying out the load cycle, the opening of the power shift clutch at the end of the shift to achieve a smooth speed and torque adjustment advantageously overlapped in time with the closing of the engine clutch.

But it is also possible to keep the engine clutch closed during a shift. In this case, the synchronization of the target gear can be useful at least supported by a change in the transmittable torque of the power shift clutch by the power shift clutch for synchronizing the target gear is further closed in an upshift and further opened in a downshift. By further closing the power shift clutch, the load on the drive motor is increased, thus delaying the input-side driveline. By further opening the power shift clutch, the drive motor is relieved and thus accelerates the input-side driveline by means of the high-speed drive motor. Due to such synchronization support, conventional synchronization means, such as friction ring synchronization devices associated with the shift clutches, for example, can be made more compact due to the lower load, or possibly completely eliminated.

To illustrate the invention, the description is a drawing attached to two embodiments. In this shows

Fig. 1 shows a first embodiment of a gearbox according to the invention in a schematic representation and

Fig. 2 shows a second embodiment of a gearbox according to the invention in a schematic representation. 1 is designed as a simple countershaft transmission with an input shaft W1, a coaxially arranged in the input shaft output shaft W2, and arranged parallel to the two transmission shafts W1, W2 countershaft W3. The input shaft W1 of the gearbox 1 is on the input side via a removable and engageable engine clutch K with a drive motor M designed as an internal combustion engine in combination. The manual transmission 1 has four forward gears and one reverse gear, which are selectively switchable.

To shift the gears, the input shaft W1 is geared internally via a first clutch K1 on the one hand in the shift position S1 with the idler gear 2a of a first gear pair 2a, 2b coupled, which due to the fixed connection of the fixed wheel 2b with the countershaft W3 a drive connection between the input shaft W1 and the countershaft W3 can be produced. Alternatively, the input shaft W1 by means of the first clutch K1 also on the other hand in the shift position S2 with the idler gear 3a of a second gear pair 3a, 3b are coupled.

By the circuit of a second clutch K2 in the shift position S3, the idler gear 3a is coupled to the output shaft W2, so that in this case (when in the switching position S2 located first clutch K1) made a direct connection of the input shaft W1 with the output shaft W2 and thus which is designed as a direct gear (i = 1) designed fourth forward gear.

The next smaller third forward gear is engaged by the switching of the first clutch K1 in the shift position S1 and the switching of the second clutch K2 in the shift position S3, wherein the power flow from the input shaft W1 via the gear pairs 2a, 2b and 3a, 3b in the output shaft W2 takes place. Similarly, the remaining courses in the sequence of second forward gear, first forward gear and reverse gear in the switching position S1 located first clutch K1 by switching the second clutch K2 in the shift position S4, by switching the third clutch K3 in the shift position S5 and by switching the third clutch K3 in the shift position S6, wherein the required direction of rotation reversal at the reverse gear is effected by the between the associated idler gear 6a and the respective fixed gear 6b arranged intermediate wheel 6c.

According to the invention designed as a friction clutch power shift clutch K 'is provided, which is arranged coaxially to the engine clutch K on the input side of the gearbox 1 and via which the drive motor M is directly connected to the output shaft W2. For this purpose, the input shaft W1 is formed as a hollow shaft and the output shaft W2 via a centrally extending within the input shaft W1 extension 12 to the transmission-side part of the Lastschältkupplung K 'out. The power-shift clutch K 'and the engine clutch K in the present case have a common clutch basket 13.

By means of the power shift clutch K ', both the engine clutch K and all clutches K1, K2, K3 can be bridged. Thus, by the temporary, at least partially closing the powershift clutch K 'all switching operations within the transmission 1 as a load circuit or partial load without a traction interruption are performed, depending on the specific control of the circuit processes, the engine clutch K during a switching operation either open or closed can be. Due to the external arrangement of the power shift clutch K 'outside of the gearbox 1 also the simple retrofitting of an existing countershaft transmission without power shift clutch to a power shift transmission is possible. A further automated manual transmission 1 'according to FIG. 2 is designed as a group transmission with a main transmission HG and a range group BNG connected downstream of it. The main transmission HG corresponds to the manual transmission 1 according to FIG. 1 and has four forward gears and one reverse gear, wherein the input shaft W1 of the main gear HG is connected to the drive motor M on the input side via the engine clutch K.

The downstream range group BNG is formed as a planetary gear with an input shaft W4 and a coaxially arranged output shaft W5, wherein the input shaft W4 is fixedly connected to the output shaft W2 of the main transmission HG. The output shaft W5 of the range group BNG thus also forms the output shaft of the entire shift transmission 1 'or group transmission.

The range group BNG is formed as a simple planetary gear set with a sun gear 7, a plurality of rotatably mounted on a planet carrier 8 and with the sun gear 7 in meshing planetary gears 9, and one with the planetary gears 9 in meshing ring gear 10. The sun gear 7 serves as an input element of the range group BNG and is therefore rigidly connected to the input shaft W4. The planet carrier 8 serves as an output element of the range group BNG and is therefore rigidly connected to the output shaft W5. The ring gear 10 is connected to the clutch basket of a fourth clutch K4 in combination, which is selectively connectable to the circuit of a low-speed gear L with the housing 11 and the circuit of a direct overdrive S with the planet carrier 8. In the low-speed gear L, the planetary gears 9 roll with a corresponding reduction of the rotational speed of the planet carrier 8 between the rotating sun gear 7 and the locked ring gear 10. In overdrive stage S, all components of the planetary gearbox run due to the coupling of the planetary gear nenrades 10 with the planet carrier 8 rigid with the speed of the sun gear 7 to.

According to the invention, a power-shift clutch K 'designed as a friction clutch is again provided, which is arranged coaxially with the engine clutch K on the input side of the main transmission HG and via which the drive motor M can be directly connected to the output shaft W5 of the range group BNG. For this purpose, the input shaft W1 and the output shaft W2 of the main transmission HG and the input shaft W4 of the range group BNG are formed as hollow shafts. In addition, the output shaft W5 of the range group BNG ends via a centrally extending within the transmission shafts W1, W2, W4 extension 12 on the transmission-side part of the power-shift clutch K '. The power-shift clutch K 'and the engine clutch K in turn have a common clutch basket 13.

By means of the power shift clutch K ', both the engine clutch K and all clutches K1, K2, K3, K4 can be bridged. Thus, by the temporary, at least partially closing the powershift clutch K 'all switching operations within the main transmission HG and the range circuits within the range group BNG as load circuit or partial load circuit can be performed without a traction interruption, depending on the specific control of the circuit processes, the engine clutch K during the switching operations can be either opened or kept closed. Due to the external arrangement of the power shift clutch K 'outside of the main transmission HG and the range group BNG also easy retrofitting of an existing group transmission without power shift clutch to a power shift transmission is possible. Bezuαszeichen

1 automated manual transmission

V automated manual transmission

2a idler gear

2b fixed wheel

3a idler gear

3b fixed wheel

4a loose wheel

4b fixed wheel

5a idler gear

5b fixed wheel

6a idler wheel

6b fixed wheel

6c intermediate wheel

7 sun wheel

8 planet carrier

9 planetary gear

10 ring gear

11 housing

12 extension

13 clutch basket

BNG area group

HG main gear i gear ratio

K engine clutch

K 'power shift clutch

K1 (first) clutch

K2 (second) clutch K3 (third) clutch

K4 (fourth) clutch

L shift position (from K4), low-speed gear (from BNG)

M drive motor

S shift position (from K4), overdrive (from BNG)

51 shift position (from K1)

52 switch position (from K1)

53 switch position (from K2)

54 shift position (from K2)

55 switch position (from K3)

56 switch position (from K3)

W1 input shaft (from 1, 1 ', HG)

W2 output shaft (from 1, HG)

W3 countershaft (from 1, HG)

W4 input shaft (from BNG)

W5 output shaft (from 1 ', BNG)

Claims

claims

1. Automated manual transmission (1, 1 ') of a motor vehicle, having an input shaft, a coaxial with the input shaft arranged output shaft, and a plurality of selectively shiftable gears via associated clutches, wherein the input shaft via an engageable and disengageable engine clutch (K) with a drive motor (M) is connected, and an additional controllable friction clutch is provided as a power shift clutch for bridging at least one of the clutches as required, characterized in that the power shift clutch (K ') directly between the drive motor (M) and the output shaft (W2 or W5) is effective by the load-shift clutch (K ') on the input side of the gearbox (1,

1 ') is arranged coaxially with the engine clutch (K) by the axially between the power shift clutch (K') and the output shaft (W2 or W5) located transmission shafts (W1 or W1, W2, W4) are formed as hollow shafts, and in that the output shaft (W2 or W5) within these transmission shafts (W1 or W1, W2, W4) is extended as far as the transmission-side part of the power-shift clutch (K ').

2. Gearbox according to Claim 1, characterized in that the power shift clutch (K ') within the clutch housing of the engine clutch (K) is arranged.

3. Gearbox according to claim 2, characterized in that the power shift clutch (K ') and the engine clutch (K) have a common clutch basket (13).

4. Gearbox according to one of claims 1 to 3, characterized in that in one embodiment of the gearbox (1) in a simple countershaft design, the input shaft (W1) of the gearbox (1) designed as a hollow shaft and the output shaft (W2) of the gearbox (1) is extended within the input shaft (W1) to the transmission-side part of the power-shift clutch (K ').

5. Manual transmission according to one of claims 1 to 3, characterized in that in one embodiment of the gearbox (1 ') as a group transmission with a main gear (HG) in a simple countershaft design and a downstream range group (BNG) in planetary design, the input shaft (W1) and the output shaft (W2) of the main gear (HG) and the input shaft (W4) of the range group (BNG) are formed as hollow shafts, and that the output shaft (W5) of the range group (BNG) within the input shaft (W4) of the range group (BNG) and within the output shaft (W2) and the input shaft (W1) of the main transmission (HG) is extended to the transmission-side part of the power-shift clutch (K ').

6. A method for switching control of an automated manual transmission of a motor vehicle having an input shaft, a coaxially arranged to the input shaft output shaft and a plurality of selectively shiftable gears via associated clutches, and in which the input shaft is connected via an engageable and disengageable engine clutch with a drive motor , wherein during a switching operation, an additional controllable friction clutch is closed as a load clutch for bridging the clutches involved in the switching operation, characterized in that in a shift between two maximum one direct gear containing gears (i> = 1) before laying out the load gear the Lastschaltkupplung (K ') for torque transfer at least partially closed and thereby a direct connection between the drive motor (M) and the output shaft (W2 or W5) is made, then the load gear is designed, then the target gear is synchronized and engaged, and finally the power shift clutch (K ') is fully opened again.

7. The method according to claim 6, characterized in that the engine clutch (K) is opened before laying out the load gear, and that the opening of the power shift clutch (K ') at the end of the shift operation overlapped with the closing of the engine clutch (K) takes place.

8. The method according to claim 6, characterized in that the engine clutch (K) is kept closed during the switching operation, and that the synchronization of the target gear by a change in the transmittable torque of the power-shift clutch (K ') is at least supported.

9. The method according to claim 8, characterized in that the power shift clutch (K ') is further closed during an upshift to synchronize the target gear.

10. The method according to claim 8, characterized in that the power-shift clutch (K ') is opened further in a downshift to synchronize the target gear.