GB2289451A - Four-wheel-drive vehicle transmission: compact layout of front and centre differentials. - Google Patents

Four-wheel-drive vehicle transmission: compact layout of front and centre differentials. Download PDF

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Publication number
GB2289451A
GB2289451A GB9508016A GB9508016A GB2289451A GB 2289451 A GB2289451 A GB 2289451A GB 9508016 A GB9508016 A GB 9508016A GB 9508016 A GB9508016 A GB 9508016A GB 2289451 A GB2289451 A GB 2289451A
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GB
United Kingdom
Prior art keywords
differential
axle
gear
drive
shaft
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9508016A
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GB9508016D0 (en
GB2289451B (en
Inventor
Klaus Lippitsch
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Steyr Daimler Puch AG
Original Assignee
Steyr Daimler Puch AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
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Application filed by Steyr Daimler Puch AG filed Critical Steyr Daimler Puch AG
Publication of GB9508016D0 publication Critical patent/GB9508016D0/en
Publication of GB2289451A publication Critical patent/GB2289451A/en
Application granted granted Critical
Publication of GB2289451B publication Critical patent/GB2289451B/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K17/00—Arrangement or mounting of transmissions in vehicles
    • B60K17/34—Arrangement or mounting of transmissions in vehicles for driving both front and rear wheels, e.g. four wheel drive vehicles
    • B60K17/344—Arrangement or mounting of transmissions in vehicles for driving both front and rear wheels, e.g. four wheel drive vehicles having a transfer gear
    • B60K17/346—Arrangement or mounting of transmissions in vehicles for driving both front and rear wheels, e.g. four wheel drive vehicles having a transfer gear the transfer gear being a differential gear

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Retarders (AREA)
  • Arrangement And Driving Of Transmission Devices (AREA)

Description

1 2289451 A DRIVE UNIT FOR A MOTOR VEHICLE HAVING A MOUNTED DISTRIBUTOR
GEAR AND A CENTRAL DIFFERENTIAL The invention relates to a drive unit for motor vehicles having a transverse engine gearbox unit, comprising a front-axle differential having wheel drive shafts, and a central differential which is driven by the output gear of the transmission, is arranged parallel to the wheel drive shafts on the side thereof facing away from the drive gear and by which the front-axle differential and a rear-axle drive shaft are driven.
A drive unit of this type is known from German patent specification 32 00 276, wherein a high-speed countershaft is driven by the output gear of the transmission via two intermediate gears not connected to any shaft and drives the inter-axle differential from within. The said inter-axle differential firstly drives the front-axle differential with two pairs of gears via a very high transmission ratio and secondly drives the rearaxle drive shaft via an angular gear. An inter-axle differential loaded with a low moment is made possible by the high-speed countershaft, and thus the overall transmission
2 ratio of the drive can also be reduced, as is desirable for cross-country driving. However, this entails a number of disadvantages. The two intermediate gears and the two gear pairs with a further intermediate gear increase costs and structural dimensions quite considerably, all the more since the intermediate gear concentric with the front-axle differential occupies the space in which the front-axle differential is housed in a conventional two-wheel drive. Thus in such drive units having a transverse engine gearbox unit, the aim is always to be able to mount them on a conventional unit as unaltered as possible. In this arrangement, the addition of a further gear on the high-speed side is most easily accepted, which then contributes to an additional cross-country gear as a result of the reduced overall transmission ratio in the adjacent drive unit.
The object of the invention is to avoid these disadvantages and to provide a drive unit of the type in question which can be mounted on an unaltered conventional unit and permits an increase in gear reduction, having an inter-axle differential under as little load as possible and with as small a spatial requirement as possible. However, it should also be able to receive a shiftable intermediate gear, also called a hi-lo group, with few alterations.
9 p 3 According to the invention, this is achieved in that the output gear drives the central differential via a first hollow shaft co-axial with the front-axle differential and in that a shaft leads from both sides of the central differential, one of the said shafts being drivably connected to the front-axle differential via a second hollow shaft co-axial with the front-axle differential, and the other being drivably connected to the rear-axle drive shaft.
As a result, the conventional front-axle unit can firstly be adopted unaltered with the front-axle differential. The first hollow shaft must transmit the entire moment, for which it has an adequate resistance moment as a hollow shaft, but can then drive the inter-axle differential at high speed and therefore with a low moment by a single gear pair with an easily variable transmission ratio. Therefore the rear-axle drive shaft can also be formed as a high-speed shaft and the front-axle differential can again be driven at the necessary low speed by a single gear pair.
However, if a shiftable intermediate gear (hi-lo group) is to be accommodated, in addition to the gear pair a second gear pair can be provided in a further development of the invention, and the first hollow shaft drives the inter-axle differential via one of these two 4 gear pairs. Thus a second gear pair simply needs to be added at a location at which there is also enough space available for the purpose.
Although in principle any differential, locking or not, is suitable as an inter-axle differential, it is a torsen differential in an advantageous further development of the invention. With this type of construction, operation at a relatively high speed has a favourable effect on operating behaviour.
The invention is described and explained in the following with reference to the drawings which show schematically:
Fig. 1: a first embodiment of the unit according to the invention; Fig. 2: a second embodiment of the unit according to the invention with a hi-lo group.
In Figure 1, the drive gear of the engine gearbox unit (not shown) is designated by 20. It drives a large gearwheel 1 having the transmission ratio also provided in the conventional two-wheel drive vehicle. The gearwheel 1 is arranged on a first hollow shaft 2 which - and this is only indicated - is mounted in the housing and carries a gearwheel 3. This drives a gearwheel 4 (the transmission ratio is il) which is connected to the cage of the inter-axle differential 5 or is formed directly on the cage. A shaft 6, 10 leads from each side of the differential 5. The shaft 6 drives the rear-axle drive shaft 19 via a bevel gear pair 7, 8 (transmission ratio i2) and the said rear-axle drive shaft 19 drives the rear-axle differential (only indicated) via a further bevel gear 9 (transmission ratio i3).
The shaft 10 drives a second hollow shaft 13 via a gear pair 11, 12 (transmission ratio i4) and the said hollow shaft 13 is drivably connected to the cage of the front-axle differential 14. The two wheel drive shafts 15, 16 lead from the said differential 14 to the front wheels (not shown).
The inter-axle differential 5 is arranged parallel to the front-axle differential 14, but on the side thereof facing away from the drive gear 20. It can be seen from the relative sizes of the gear pairs 3, 4 and 11, 12 that the inter-axle differential 5 rotates more quickly than the frontaxle differential 14. By appropriately selecting the numbers of teeth, the overall transmission ratio can be reduced to the value desired for slow cross-country driving.
6 Should the central differential 5 execute no relative movement during non- slip straight travel, the product of the transmission ratios i2 and i4 should be approximately equal to the transmission ratio i3. In this embodiment, the inter-axle differential 5 is a conventional bevel-gear differential. A locking clutch 21 can be provided for the locking thereof.
The embodiment of Figure 2 differs therefrom only in that the inter-axle differential 5 is formed as a torsen differential and in that, in addition to the gear pair 3, 4, a further gear pair 17, 18 (transmission ratio i5) is provided. Of these two gear pairs, either one or the other gearwheel 3, 17 is connected to the first hollow shaft 2. A hi-lo group is thus formed.
4 1 7

Claims (4)

1. A drive unit for a motor vehicle having a transverse engine gearbox unit, comprising a front-axle differential having wheel drive shafts, and a central differential driven by an output gear of the transmission and arranged parallel to the wheel drive shafts on the side thereof facing away from the drive gear and by means of which the front-axle differential and a rear-axle drive shaft are driven, characterised in that the output gear drives the central differential via a first hollow shaft co-axial with the front-axle differential and in that a shaft leads from both sides of the central differential, one of the said shafts being drivably connected to the front-axle differential via a second hollow shaft co-axial with the front-axle differential, and the other of the said shafts being drivably connected to the rear-axle drive shaft.
2. A drive unit according to claim 1, wherein first and second gear pairs are provided and the first hollow shaft drives the central differential via one of these two gear pairs.
3. A drive unit according to claim 1 or 2, wherein the central differential is a torsen differential.
8
4. A drive unit substantially as herein described with reference to the embodiment shown in Figure 1 or Figure 2 of the accompanying drawings.
GB9508016A 1994-05-11 1995-04-20 A drive unit for a motor vehicle having a central differential Expired - Lifetime GB2289451B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19944416678 DE4416678A1 (en) 1994-05-11 1994-05-11 Drive unit for motor vehicles with add-on transfer case and central differential

Publications (3)

Publication Number Publication Date
GB9508016D0 GB9508016D0 (en) 1995-06-07
GB2289451A true GB2289451A (en) 1995-11-22
GB2289451B GB2289451B (en) 1998-02-18

Family

ID=6517901

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9508016A Expired - Lifetime GB2289451B (en) 1994-05-11 1995-04-20 A drive unit for a motor vehicle having a central differential

Country Status (2)

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DE (1) DE4416678A1 (en)
GB (1) GB2289451B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11285808B2 (en) 2017-11-10 2022-03-29 Syn Trac Gmbh Modular drive train and a vehicle comprising such a drive train

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4700800A (en) * 1986-02-11 1987-10-20 Steyr-Daimler-Puch Ag Drive system for motor vehicles
US4875978A (en) * 1986-08-20 1989-10-24 Mazda Motor Corporation Vehicle four wheel drive system
EP0387053A2 (en) * 1989-03-10 1990-09-12 Fuji Jukogyo Kabushiki Kaisha Differential device for a four-wheel drive vehicle
EP0409529A1 (en) * 1989-07-20 1991-01-23 Fuji Jukogyo Kabushiki Kaisha Torque distribution control system for a four-wheel drive motor vehicle
EP0413436A1 (en) * 1989-07-20 1991-02-20 Fuji Jukogyo Kabushiki Kaisha Torque distribution control system for a four-wheel drive motor vehicle

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4700800A (en) * 1986-02-11 1987-10-20 Steyr-Daimler-Puch Ag Drive system for motor vehicles
US4875978A (en) * 1986-08-20 1989-10-24 Mazda Motor Corporation Vehicle four wheel drive system
EP0387053A2 (en) * 1989-03-10 1990-09-12 Fuji Jukogyo Kabushiki Kaisha Differential device for a four-wheel drive vehicle
EP0409529A1 (en) * 1989-07-20 1991-01-23 Fuji Jukogyo Kabushiki Kaisha Torque distribution control system for a four-wheel drive motor vehicle
EP0413436A1 (en) * 1989-07-20 1991-02-20 Fuji Jukogyo Kabushiki Kaisha Torque distribution control system for a four-wheel drive motor vehicle

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11285808B2 (en) 2017-11-10 2022-03-29 Syn Trac Gmbh Modular drive train and a vehicle comprising such a drive train

Also Published As

Publication number Publication date
DE4416678A1 (en) 1995-11-16
GB9508016D0 (en) 1995-06-07
GB2289451B (en) 1998-02-18

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Legal Events

Date Code Title Description
PE20 Patent expired after termination of 20 years

Expiry date: 20150419