GB2129075A

GB2129075A - A drive unit for motor vehicles with a hydrodynamic torque converter

Info

Publication number: GB2129075A
Application number: GB08328777A
Authority: GB
Inventors: Hans-Joachim Forster; Hermann Gaus; Jurgen Pickard; Erwin Nussbaumer
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1982-10-28
Filing date: 1983-10-27
Publication date: 1984-05-10
Also published as: FR2535262A1; JPS5999166A; DE3239947A1; GB8328777D0

Abstract

A drive unit comprises an hydrodynamic torque converter 12, 13, 41 and an epicyclic overdrive gear unit 17 which may be interposed into the drive line between the input shaft 14 and impeller rotor 12 by means of a gear-shift element 15. To enable the torque converter to participate independently of the overdrive gear unit 17, the input shaft may additionally be brought into a driving connection with the impeller rotor 12 by means of a freewheel clutch device 19 for the traction or drive operations which blocks lagging of the impeller rotor in the rotational drive direction and does permit overtaking (over- running). The gear shift element 15 is operatively disposed between the overdrive gear unit 17 and the impeller 12, or a non-rotary housing component 20. <IMAGE>

Description

SPECIFICATION A drive unit for motor vehicles with a hydrodynamic torque converter The invention relates to a drive unit for motor vehicles including a hydrodynamic torque converter having an impeller rotor and a turbine rotor with a turbine rotor shaft rotationally fast therewith and with an input shaft adapted to be driven by a driving engine, an overdrive gear unit with an individual transmission ratio less than one adapted to be interposed in the transmission drive path between the input shaft and impeller rotor by means of a gear shift element.

In a known drive unit of this kind (US-PS 30 54 307) the turbine rotor shaft operates as input shaft of an automatic gear change unit, a direct connection being established between the main shaft of the driving engine and the turbine rotor shaft on leaving the starting range, through a bypass clutch.

In contrast, it is the object of the invention, to provide a drive unit in which the torque converter participates in the torque transmission in other gears as well, independently of the overdrive unit, in particular, to use the torsional vibration damping property of the torque converter, whilst dispensing with a bypass clutch.

According to the present invention there is provided a drive unit for motor vehicles including a hydrodynamic torque converter having an impeller rotor and a turbine rotor with a turbine rotor shaft rotationally fast therewith and with an input shaft adapted to be driven by a driving engine, an overdrive gear unit with an individual transmission ratio less than one adapted to be interposed in the transmission drive path between the input shaft and impeller rotor by means of a gear shift element wherein the input shaft is adapted additionally to be brought into a driving connection with the impeller rotor for drive operations, by means of a clutch device which blocks lagging of the impeller rotor in the rotational drive direction and permits over-riding, the gear shift element being operatively interposed between the overdrive gear unit and the impeller rotor or a non-rotatable housing part.

Embodiments of the invention will now be described by way of example with reference to the drawings in which: Figure 1 shows a first embodiment of a drive unit in accordance with the invention with an automatic gear change unit placed downline in the force transmission, Figure 2 shows a second embodiment of a drive unit in accordance with the invention wherein, as in Figure 1, the overdrive gear unit is structurally disposed ahead of the torque converter, Figures 3 to 6 show four further embodiments of a drive unit in accordance with the invention wherein the overdrive gear unit is disposed structurally behind the torque converter and, Figures 7 to 9 show three embodiments of a drive unit in accordance with the invention wherein the overdrive gear unit is wholly or partially disposed concentrically between the outer torus of the torque converter on the one hand and a stator shaft on the other hand.

The embodiments of Figures 1 to 9 agree in the following characteristics: A drive unit 10 placed ahead of an automatic gear change unit 46 in the flow line of force i.e.

the transmission drive path between a power source and a drive element, has a hydrodynamic torque converter 11 with an impeller rotor 12, a turbine rotor 13 and a stator 41. The turbine rotor 1 3 is rigidly connected to a concentric turbine rotor shaft 1 8 which constitutes the input shaft of the automatic gear change unit 46. The stator 41 is anchored through a free wheel 42 immovably in the usual way, in the direction of rotation opposite to the direction of rotational drive with respect to the non-rotary gear housing 64 of gear change unit 46, by means of a stator shaft 33 concentrically surrounding the turbine rotor shaft 18.The hydrodynamic torque converter 11 is enveloped by a drive bell 21 which at its front end, is connected to an input shaft 14 adapted to be driven by a driving engine (not shown) and which in its zone lying on the opposite side of torque converter 11, is connected to a pump drive shaft 24 of a primary pump 25 for the pressure supply of the gear change unit 64. Between impeller rotor 12 and drive bell 21, there is operatively interposed into the torque transmission between whose planet carrier 26 is connected to the drive belt 21. The overdrive gear unit 1 7 may be inerposed into the torque transmission between input shaft 14 and impeller rotor 12 by a gear shift clutch or 1 5, 1 6, the overdrive gear unit 17 being necessarily brought to a component gear ratio which is less than 1.Whilst in the embodiments of Figures 1, 3 and 4, a disc clutch is used as the gear shift clutch, the remaining embodiments of Figures 2 and 5 to 9 have a multidisc clutch for this purpose. A second drive connection between the input shaft 14 and impeller rotor 12 may be established in the traction operations independently of the overdrive unit 1 7 by means of a free wheel 1 9, if the gear shift clutch 1 5 or 1 6 respectively is disengaged. The free-wheel 1 9 does, in the drive direction, block over-running of the impeller by drive bell 21.While the respective clutch 1 5 is, in the case of the embodiments of Figures 1,3 and 4, operatively interposed between the overdrive gear unit 1 7 and impeller rotor 12, the respective brake 1 6 operates, in the embodiments of Figures 2 and 5 to 9, between overdrive gear unit 1 7 and a non rotary brake housing component 20. The connection between the overdrive gear unit 17 and impeller rotor 12 is led, via a driving cylinder 27 rigidly connected to impeller rotor 12 which, if a clutch 1 5 in accordance with the embodiments of Figures 1,3 and 4 is used, is connected indirectly through this clutch and in the remaining embodiments of Figures 2 and 5 to 9 with a gearing brake 16, it is rigidly connected to the outer central gear wheel 29 of the overdrive gear unit 17.

The turbine rotor shaft 1 8 leads to the larger central gear wheel at the rear 48, of a Ravigneaux set 47 which is connected to a second epicyclic gear unit 63. A main planet 52 of the Ravigneaux set meshes additionally both with an outer central gear wheel 50 on planet carrier 51. The side planet 53 meshes, moreover, with a second smaller central gear wheel 49. Whilst planet carrier 51 is connected to the outer central gear 54 of the rear epicyclic gear unit 63, an output shaft 57 of gear change unit 46 which may be connected to the vehicle wheels in the usual way, is linked to the planet carrier 55 of the rear gear unit 63. The outer central gear wheel 50 of the Ravigneaux set may be coupled with the inner central gear 56 of the gear planet gear unit 63 both through a gearing clutch 58 and through a freewheel 59.The two inner central gear wheels 49 and 56, as well as the front planet carrier 51 may each be locked by one gearing brake 62 or 65 or 60 respectively. Finally, the Ravigneaux set 47 may also be blocked by a gearing clutch 61 disposed between the inner central gear wheel 49 and the planet carrier 51.

The same gear change unit 46 is used with all the modes of embodiment of Figures 1 to 9. The drive unit 10 in accordance with the invention does not, however, depend on the design of the gear change unit 46 as will be explained below in greater detail.

In the embodiments of Figures 1,3 to 5, 8 and 9, free wheel 1 9 for the traction operations is located between drive bell 21 and the driving cylinder 27 of the impeller rotor 12.

On the other hand, in the embodiments of Figures 2, 6 and 7, the free wheel 19 is located operatively between drive bell 21 and the inner central gear wheel 28 of the overdrive gear unit 1 7 which may be locked by the gearing brake 1 6.

In this arrangement, free wheel 1 9 prevents the over-running of input shaft 1 4 by the inner central gear wheel 28 in the rotational drive direction so that the outer central gear wheel 29 of the overdrive gear unit, rigidly connected to impeller rotor 12, is also driven at the same speed of rotation as input shaft 14.

In the embodiments of Figures 1,3 and 4, the inner central gear wheel 28 of the overdrive gear unit 1 7 is fixed against rotation with respect to brake housing 20 -- whilst the outer central gear wheel 29 of the overdrive gear unit 1 7 is connected to the brake housing 20 by a brake with impeller rotor 12 through the clutch 15. In this arrangement too, the inner central gear wheel 28 of the overdrive gear unit 1 7 could, of course, be connected to the brake housing20 by a brake with a release facility.

In the case of the embodiments of Figures 2 and 5 to 7 operating with a gearing brake 1 6 in the overdrive gear unit 17, the driving cylinder 27 of impeller rotor 1 2 is rigidly connected to the outer central gear wheel 29 of the overdrive gear unit 17.

The two embodiments of Figures 1 and 2 have in common that the overdrive gear unit 1 7 is located ahead of torque converter 11, that is, the torque converter 11 is located between the gear unit 17 and the main gear unit 46. In this arrangement, planet carrier 26 is axially connected on both sides with radial drive link shaft, 22 or 30 respectively of which the rear drive link shaft 30 is connected to input shaft 14 and the front drive link shaft 22 with drive bell 21.

Finally, the embodiments of Figures 1 and 2 have in common that the driving cylinder 27 is not connected directly to impeller rotor 12 but through an inner drive shell 31.

The driving drum 27 of the embodiments of Figures 1 and 3 is disposed in an axially compact mode of construction concentrically between free wheel 1 9 for the traction operations clutch 1 5.

In the embodiments of Figures 2 and 9, a seal 32 is arranged to operate between drive bell 21 and driving cylinder 27 in order to keep the liquid friction on the inner wall of drive bell 21 to a low level.

In the embodiments of Figures 3 to 9 the overdrive gear unit 1 7 is structurally disposed behind torque converter 11 with a special feature shown in Figure 6 - wherein the primary pump 25 is situated axially between the torque converter and overdrive gear unit 1 7 - and with a seond special feature shown in Figures 7 to 9, according to which the overdrive gear unit 1 7 is radially moved inward, and moreover, displaced forward in the direction of stator -- free wheel 42.

The inner central gear wheel 28 of the overdrive gear unit 1 7 may, as a reaction element, be locked against rotation with respect to stator shaft 33, directly in the embodiments of Figures 3 and 4, and on the other hand, in the embodiments of Figures 5 and 7 to 9 indirectly through gearing brake 1 6. In the embodiment of Figure 6, free wheel 19, the overdrive gear unit 1 7 and gearing brake 1 6 are located concentrically within each other and approximately centrally to a plane normal to the axis of rotation.

The rear position of overdrive gear unit 17 in relation to torque converter 11 and the locking of the reaction element (the inner central gear wheel 28) is illustrated in Figure 6).

In the embodiment of Figure 4, the clutch 1 5 and driving cylinder 27 lie within the annular core zone 34 in the torque converter 11. The clutch 1 5 is connected to the outer central gear wheel 29 of the overdrive gear unit 1 7 through a moving drive link shaft 66 traversing a gap between impeller rotor 12 and stator 41.

In the embodiments of Figures 3 and 4, the inner central gear wheel 28 of overdrive gear unit 1 7 used as a reaction element, is connected directly to stator shaft 33.

In the embodiment of Figure 5 where the primary pump 25 is axially disposed between the overdrive gear unit 17 and gearing brake 16, a hollow shaft 35 disposed concentrically between pump drive shaft 24 and stator shaft 33 is connected at one end to the inner central gear wheel 28, used as the reaction element, and at the other end, to gearing brake 1 6.

In the embodiment of Figure 6 with the primary pump 25 disposed axially between torque converter 11 and the overdrive gear unit 17, drive bell 21 is connected to the pump drive shaft 24 via a radial link shaft 23, the latter being additionally connected with the inner race 44 of free wheel 1 9 for the traction operations, as well as via a radial drive link shaft 37 with the planet carrier 26 of the overdrive gear unit 17. A hollow shaft 36 located concentrically between pump drive shaft 24 and stator shaft 33 is rigidly connected at its front end to impeller rotor 12 and at its rear end, to the driving drum 27 which is rigidly connected to the outer central gear wheel 29.

In the embodiments of Figures 6, 8 and 9, the impeller rotor 12 of torque converter 11 may be connected to the drive bell 21 through a further clutch device 38 or 39 respectively, to make it possible to brake with the engine on the over-run.

In the embodiments of Figures 8 and 9, provision is made for a counter free wheel 38 which locks the inner central gear wheel 28 as reaction element in the over-run condition, with respect to stator shaft 33, in the rotational drive direction.

Finally, in the embodiment of Figure 6 it is, moreover, material and advantageous that pump drive shaft 24 is connected with the inner central gear 28 of the overdrive gear unit through the free wheel 1 9 for traction operation.

The embodiments of Figures 7 to 9 having in common that the gearing brake 1 6 of the overdrive unit 1 7 is disposed concentrically between stator shaft 33 and an outer torus 40 whose geometric contour is defined by the shape of the outer shells of impeller rotor 12 and stator 13.

The embodiments of Figures 7 to 9 have, moreover, a brake drum 20 in common, which is rigidly connected to stator shaft 33 and accommodates gearing brake 1 6. Into brake drum 20, there extends, traversed by stator shaft 33, a hollow shaft 35 through which the gearing brake 1 6 is connected to the inner central gear wheel 28.

Moreover, the embodiments of Figures 7 to 9 have in common that the brake housing 20 is used as mounting for the stator 41.

Finally, the embodiments of Figures 7 to 9 have, moreover, in common that the brake housing 20 is disposed axially between free wheel 42 supporting stator 41 in relation to stator shaft 33 and the overdrive gear unit 1 7.

In the two embodiments of Figures 8 and 9, there is, in addition, arranged radially, a counter free wheel 38 on the inside towards outer torus 40 -- thus concentrically between gearing brake 16 and stator shaft 33.

The embodiments of Figures 8 and 9 are distinguished by a particularly compact mode construction in that both the overdrive gear unit 1 7 and the driving cylinder 27, rigidly fixed to impeller rotor 12, are also additionally arranged between outer torus 40 and stator shaft 33.

In the embodiment of Figure 9, the driving cylinder 27 and the overdrive gear unit 1 7 are disposed axially in the transition zone between impeller rotor 12 and stator 41 - thus wholly within the frontal radial boundary planes of torque converter 11.

Moreover, in the embodiment of Figure 9, the drive bell 21 is connected with the outer central gear wheel 29 of the overdrive gear unit 17, through free wheel 1 9 for the traction operations.

To make it possible to accommodate free wheel 1 9 between outer torus 40 and stator shaft 33, the overdrive gear unit 1 7 is designed as a friction gear unit wherein there extend axially, the segmentary race components 43 of planet carrier 26 into the gaps between two planet wheels 67 which are adjacent in the peripheral direction. One of the two central gear wheels 28 and 29 of the overdrive gear unit 17 - in this case, the outer central gear wheel 29 - is itself directly formed as race 44 for the clutch elements of free wheel 19.

As a variant of the embodiment of Figure 9, it is also possible to design the overdrive gear unit 1 7 in the usual way, as a toothed gear unit wherein -just as in the embodiments of Figures 5 and 8 -the respective central gear wheel 29 and the one race 44 of respectively 45 of free wheel 19 are axially disposed next to each other and they may also be formed integrally Within the framework of the invention, features of one embodiment may, as a matter of course, also be used in the other embodiments. In the same way, the type and design of gear change unit 46 is not dependent on the design of the drive unit 10 and may be of any kind.

In the drive unit according to the invention, with a five speed gear unit with overdrive, it is not absolutely necessary to brake with the engine in first gear. For this reason, a special through coupling was dispensed with for the overdrive and only a free wheel for the traction operations was used.

With the drive unit in accordance with the invention, it is possible to dispense with the overdrive only on starting and to start with the full gear ratio of the first gear. The overdrive may then be added as 1/2 gear and to operate the remaining gears invariably with overdrive.

The overdrive unit may be arranged not to operate in the first and second gears of gear change unit 46 and only in third gear.

In the drive unit in accordance with the invention, it is possible to dispense with the use of a by-pass clutch for the torque converter because its firmness is substantially enhanced by driving the impeller rotor at high speeds.

In the drive unit in accordance with the invention, it is advantageous that the primary pump for the pressure supply of the automatic gear change 46 continues to operate at the rotational speed of the engine and that the rotational engine speed in relation to the output speed of the gearing may be reduced in several gears by the overdrive value.

With reference to the embodiment of Figure 1, it should be observed that in the gear change unit 46, four forward gears and a reverse gear may be formed in the following way, the flow line of force i.e. the transmission drive path in drive unit 10 being respectively disposed from input shaft 1 4 via planet carrier 26, drive bell 21, free wheel 19 and further via the torque converter 11 to the turbine rotor shaft 1 8.

In first gear, gearing clutch 58 and gearing brake 65 are engaged and free wheel 59 is operative.

In second gear, the gearing brakes 62 and 65 are engaged.

In third gear, the gearing clutch 61 and gearing brake 65 are engaged.

In fourth gear, the gearing clutches 61 and 58 are engaged to form a transmission ratio of 1:1.

In reverse gear, gearing clutch 58 and gearing brake 60 are engaged and free wheel 59 is operative.

Now through overdrive gear unit 17, an additional fifth forward gear may be formed with an overall transmission ratio smaller than 1 in that all gearing clutches 61,58 and 1 5 are engaged and that the inner central gear 28 in overdrive gear unit 17 is used solely as reaction element.

Since all three clutches are operative, one may also brake with the engine in this gear.

Such engine braking (thrust operation) may also be obtained in the remaining gears, if the gearing clutch 1 5 of overdrive gear unit 17 is engaged additionally which can thus also take over the function of the counter free wheel 38 of Figures 8 and 9 or respectively of gearing clutch 39 of Figure 6.

Claims

1; A drive unit for motor vehicles including a hydrodynamic torque converter having an impeller rotor and a turbine rotor with a turbine rotor shaft rotationally fast therewith and with an input shaft adapted to be driven by a driving engine, an overdrive gear unit with an individual transmission ratio less than one adapted to be interposed in the transmission drive path between the input shaft and impeller rotor by means of a gear shift element wherein, the input shaft is adapted additionally to be brought into a driving connection with the impeller rotor for drive operations, by means of a clutch device which blocks lagging of the impeller rotor in the rotational drive direction and permits overriding, the gear shift element being operatively interposed between the overdrive gear unit and the impeller rotor or a non-rotatable housing part.

2. A drive unit accordimg to claim 1, wherein a drive bell enveloping the torque converter is fast both to the input shaft and to a drive shaft of a primary pump located on the opposite side of the torque converter to said input shaft, as well as additionally to a planet carrier of the overdrive gear unit.

3. A drive unit according to claim 1 or 2, wherein a driving drum fast to the impeller rotor is adapted to be brought into a driving connection with the overdrive gear unit.

4. A drive unit according to any of claims 1 to 3, wherein, a drive bell is connected to a driving cylinder via said clutch device for traction operations.

5. A drive unit according to any one of claims 1 to 3, wherein, a drive bell is connected through said clutch device for traction operations to a reaction element lockable by a gearing brake of the overdrive gear unit.

6. A drive unit according to any one of claims 1 to 4, wherein, the reaction element of the overdrive gear unit is fixed against rotation and a third gear element of the overdrive gear unit is adapted to be coupled with a driving cylinder through a gearing clutch.

7. A drive unit according to claim 5, wherein, the reaction element of the overdrive gear unit may be locked by a gearing brake and that said third gear element of the overdrive gear unit is rigidly connected to the driving cylinder.

8. A drive unit according to claim 7, wherein, the overdrive gear unit is rigidly disposed axially between two radial drive line shafts respectively connected rigidly to a planet wheel carrier, and one drive link shaft is rigidly connected to the drive bell and the other drive link shaft is rigidly connected to the input shaft.

9. A drive unit according to claim 7 or 8, wherein, an inner central gear wheel of the overdrive gear unit is used as a reaction element and the drive link shaft disposed between the overdrive gear unit and the torque converter is connected to the input shaft.

10. A drive unit according to one of claims 7 to 9, wherein, a drive shell located within the drive bell envelops the turbine rotor and is respectively connected rigidly on the one hand to the impeller rotor and on the other hand, to driving cylinder

11. A drive unit according to any one of claims 6 to 10, wherein, the driving cylinder is disposed concentrically between a radial outer clutch device for the traction operations and the radial inner gearing clutch.

12. A drive unit according to one of claims 7 to 10, wherein, a seal is arranged between drive bell and driving cylinder.

13. A drive unit according to claim 11 or 12, wherein, a hollow stator shaft disposed concentrically between turbine shaft and pump drive shaft is secured against rotation to a nonrotatable housing part and the overdrive gear unit is disposed on the side of torque converter which is on the opposite side from said input shaft, and the reaction element of overdrive gear unit is adapted to be rotationally fast with said stator shaft permitting rotation.

14. A drive unit according to claim 13, wherein, the driving cylinder and gearing clutch are disposed within the annular core zone of the torque converter.

1 5. A drive unit according to claim 13 or 14, wherein, the reaction element is rigidly connected to the stator shaft.

1 6. A drive unit according to any one of claims 13 to 1 5, an inner central gear wheel is used as a reaction element.

17. A drive unit according to claim 13, wherein, the primary pump is disposed axially between the overdrive gear unit and gearing brake, a hollow shaft is disposed concentrically between stator shaft and pump drive shaft and the hollow shaft is connected at one end to the reaction element and on the other end to the gearing brake.

1 8. A drive unit according to claim 7, wherein, the primary pump is disposed axially between the torque converter and the overdrive gear unit and a hollow shaft disposed concentrically between a pump drive shaft and stator shaft is rigidly connected at one of its ends to the impeller rotor and at its other end to the driving cylinder, the pump drive shaft being rigidly connected to a planet gear carrier.

19. A drive unit according to claim 13 or 18, wherein the overdrive gear unit has gear switch means to bring the impeller rotor in drive conditions into a driving connection with the input shaft via the overdrive gear unit.

20. A drive unit according to claim 1 8 or 1 9, wherein, the central gear wheel which is adapted to be locked by a gearing brake and the pump drive shaft are interconnected through a free wheel for the drive operations.

21. A drive unit according to any one of claims 1 8 to 20, wherein, the driving cylinder is connected to the planet carrier through a gearing clutch for the drive conditions.

22. A drive unit according to claims 13 or 19, wherein, the gearing brake is disposed concentrically between the outer torus formed geometrically by the outer shells of bladed rotors of the torque converter and the stator shaft.

23. A drive unit according to claim 22, wherein, a cylindrical brake housing rigidly connected to said stator shaft and a hollow shaft traversed by said stator shaft and rigidly connected to the inner central gear are interconnected through said gearing brake.

24. A drive unit according to claim 22 or 23, wherein, the stator of the torque converter is mounted on the brake housing.

25. A drive unit according to any one of claims 22 to 24, wherein, the brake housing is disposed axially between a free wheel connecting the stator with the stator shaft and the overdrive unit.

26. A drive unit according to claim 22 or 23, wherein, the inner central gear wheel is connected to the stator shaft through a counter free wheel for the drive conditions.

27. A drive unit according to claim 26, wherein, the counter free wheel for the drive conditions is disposed concentrically between the gearing brake and stator shaft.

28. A drive unit according to any one of claims 22 to 27, wherein, the driving cylinder and the overdrive gear unit are disposed concentrically between the outer torus of the torque converter and the stator shaft.

29. A drive unit according to any one of claims 22 to 28, wherein, the driving cylinder and the overdrive gear unit are disposed axially in the transition zone between the impeller rotor and the stator.

30. A drive unit according to any one of claims 22 to 29, wherein, the drive bell is connected to an outer central gear wheel through a free wheel for drive operations.

31. A drive unit according to any one of claims 22 to 30, wherein, the free wheel for the drive operations is disposed concentrically between a central gear wheel and a segmentary race component of the planet carrier.

32. A drive unit according to any one of claims 22 to 31, wherein, a toothless epicyclic friction gear unit is used as the overdrive gear unit and that one central gear wheel is designed as the race of the free wheel for the drive operations.

33. A drive unit according to any one of claims 22 to 31 , wherein the one central gear wheel of the overdrive gear unit and one race of the free wheel for the drive operations are both located axially next to each other and are formed integrally.

34. A drive unit for motor vehicles substantially as described herein with reference to and as illustrated in any one of more of the Figures of the accompanying drawings.