WO1991019117A1 - Differential drive assembly - Google Patents

Differential drive assembly Download PDF

Info

Publication number
WO1991019117A1
WO1991019117A1 PCT/GB1991/000817 GB9100817W WO9119117A1 WO 1991019117 A1 WO1991019117 A1 WO 1991019117A1 GB 9100817 W GB9100817 W GB 9100817W WO 9119117 A1 WO9119117 A1 WO 9119117A1
Authority
WO
WIPO (PCT)
Prior art keywords
gear
rotation
output shafts
input shaft
wheel
Prior art date
Application number
PCT/GB1991/000817
Other languages
French (fr)
Inventor
Michael Joseph Egan
Original Assignee
Barton, Gordon, Page
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
Publication date
Application filed by Barton, Gordon, Page filed Critical Barton, Gordon, Page
Publication of WO1991019117A1 publication Critical patent/WO1991019117A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D11/00—Steering non-deflectable wheels; Steering endless tracks or the like
    • B62D11/02—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides
    • B62D11/06—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides by means of a single main power source
    • B62D11/10—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides by means of a single main power source using gearings with differential power outputs on opposite sides, e.g. twin-differential or epicyclic gears
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
    • F16H37/02—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
    • F16H37/06—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts
    • F16H37/08—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing
    • F16H37/0806—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with a plurality of driving or driven shafts

Definitions

  • This invention relates to a differential drive assembly , and in the preferred embodiment provides a drive assembly for driving a pair of output shafts from a common rotary input shaft and for permitting differential rotation of the output shafts .
  • the preferred differential assembly is particularly suitable for use in motor vehicles, and may be used to effect steering of a motor vehicle, for example a tracked vehicle, by causing differential rotation of the output shafts .
  • a device for driving a pair of output shafts from a common rotary input shaft and for permitting differential rotation of the output shafts relative to each other comprising: means coupling the input shaft to a ring gear whereby the ring gear is rotated in response to rotation of the input shaft; two planetary gear sets , each in mesh with the ring gear and each having a respective planetary gear carrier for driving connection with a respective one of the output shafts; respective sun gears for each planetary gear set; and means for rotating one sun gear relative to the other sun gear to produce differential rotation of the output shafts.
  • each sun gear is provided with a worm wheel , and each worm wheel has associated therewith a worm for rotating the worm wheel and with it the associated sun gear.
  • the worms each carry a gear wheel , and the gear wheels of the worms are in mesh with a common gear wheel whereby rotation of the common gear wheel simultaneously rotates the worms to produce oppositely directed rotation of the sun gears.
  • Figure 1 is a schematic part sectional view of a preferred embodiment of the invention.
  • Figures 2-4 are cross-sections taken respectively on the lines AA, BB, and CC of Figure 1.
  • the differential assembly as shown in Figure 1 is contained within a housing 5 and comprises an input shaft 2 adapted to receive rotary input from an appropriate prime mover by way of an input flange 1.
  • the input shaft 2 carries a pinion 3 which is in mesh with a crown wheel 4 secured to an internally toothed ring gear 6.
  • rotation of the input shaft 2 causes rotation of the ring gear 6 about an axis transverse to the axis of the input shaft .
  • planetary gear sets 9, 10 each comprising four planetary gears mounted on a respective planetary gear carrier 7, 8.
  • the gear carriers are internally splined for driving connection with respective output shafts 19, 20 and are held in spaced apart configuration by a central spacer 18.
  • Each planetary gear set has associated therewith a respective sun gear 11a, 12a and each sun gear carries a respective worm wheel 11 ,12.
  • Appropriate bearings are provided for supporting all the rotating components within the casing of the differential .
  • Each worm gear wheel 11 , 12 is in mesh with a respective worm 31 , 33 of opposite hand, the worms 31 , 33 being keyed to rotate on respective shafts 30, 32 and carrying respective gears 27, 29 which are in mesh with a common gear 28 carried by a control shaft 37.
  • the control shaft 37 is rotated in the appropriate sense to rotate the gears 27, 29 and with them the worms 31 , 33 in the same direction. Because of the opposite hand of the worms this will result in oppositely directed rotation of the worm wheels 11,12 and the associated sun gears 11a, 12a .
  • the effect of this will be to increase the rotational speed of one planetary gear set and reduce the rotational speed of the other planetary gear set, resulting in corresponding respective increases and decreases in the rotational speed of the output shafts 19, 20. As soon as the period of differential rotational speed is no longer required rotation of the control shaft 37 is stopped and the output shafts 19, 20 immediately return to rotation at the same speed.
  • the described differential assembly is particularly suitable for use in effecting steering of a vehicle of the type in which steering is effected by differential rotation of driving arrangements on opposite longitudinal sides of the vehicle.
  • Such steering systems are used, for example, in civil engineering plant, for example tracked vehicles.
  • the proposed differential unit offers significant advantages.
  • a suitable actuator for example a rotary hydraulic motor, can be connected to the control shaft 37 and used to effect the desired differential rotation of the output shafts 19, 20. Since rotation of the control shaft 37 simultaneously effects an increase in speed of rotation of one output shaft and a decrease in speed of rotation of the other output shaft, using the device for steering offers the advantage that the centre line of the vehicle remains on the centre line of the turning circle during steering operations.
  • the shafts 30, 32 of the worms 31 , 33 may be directly coupled to suitable rotary actuators for example hydraulic motors . If separate actuators are provided for the worms, the actuators may be rotated in opposite directions to effect simultaneous increase and decrease of the rotational speed of the output shafts, or only one actuator need be operated, thereby effecting an increase or decrease in the speed of one output shaft .
  • mechanical means may be provided for rotating either a single control shaft 37, or separately and directly rotating the worm shafts 30, 32.
  • rotary power may be taken from a suitable power take-off point and applied via one or more torque converters to the shaft 37 or the shafts 30, 32.
  • embodiments of the invention may be used in other vehicle applications, for example to achieve optimum power distribution between the drive wheels of a wheeled vehicle.
  • relatively high speed control of the worms would be required via suitable microprocessor control so that the rotational speeds of the output shafts would be matched to the particular requirements of the vehicle during, e. g. cornering or traversing undulating surfaces .
  • optimum conditions can be obtained consistent with . permanent drive to each driven wheel .
  • worm wheels 11 , 12 are replaced by respective bevel gears which mesh with a common pinion whereby rotation of the pinion will cause oppositely directed rotation of the bevel gears .
  • the above described differential assembly may be formed as a self contained unit, in which case the output shafts 19, 20 may be inserted after the differential unit itself has been secured in position.
  • the differential unit may be incorporated within the gear box, e. g. of a transversely mounted motor car engine with drive to the ring gear being taken directly from the output of the vehicle gear box .

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Retarders (AREA)

Abstract

A device for driving a pair of output shafts (19, 20) from a common rotary input shaft (2) and for permitting differential rotation of the output shafts relative, to each other. The device comprises means (3, 4) for coupling the input shaft to a ring gear (6) so that the ring gear is rotated in response to rotation of the input shaft, and two planetary gear sets (9, 10) each in mesh with the ring gear and each having a respective planetary gear carrier (7, 8) for driving connection with a respective one of the output shafts. Each planetary gear set has a respective sun gear (11a, 12a) and means (11, 12, 31, 33) are provided for rotating one sun gear relative to the other sun gear to produce differential rotation of the output shafts.

Description

DIFFERENTIAL DRIVE ASSEMBLY
This invention relates to a differential drive assembly , and in the preferred embodiment provides a drive assembly for driving a pair of output shafts from a common rotary input shaft and for permitting differential rotation of the output shafts . The preferred differential assembly is particularly suitable for use in motor vehicles, and may be used to effect steering of a motor vehicle, for example a tracked vehicle, by causing differential rotation of the output shafts .
According to one aspect of the present invention there is provided a device for driving a pair of output shafts from a common rotary input shaft and for permitting differential rotation of the output shafts relative to each other, the device comprising: means coupling the input shaft to a ring gear whereby the ring gear is rotated in response to rotation of the input shaft; two planetary gear sets , each in mesh with the ring gear and each having a respective planetary gear carrier for driving connection with a respective one of the output shafts; respective sun gears for each planetary gear set; and means for rotating one sun gear relative to the other sun gear to produce differential rotation of the output shafts.
In one embodiment of the invention each sun gear is provided with a worm wheel , and each worm wheel has associated therewith a worm for rotating the worm wheel and with it the associated sun gear. In a particularly preferred embodiment of the invention the worms each carry a gear wheel , and the gear wheels of the worms are in mesh with a common gear wheel whereby rotation of the common gear wheel simultaneously rotates the worms to produce oppositely directed rotation of the sun gears.
The invention will be better understood ξrom the following description of a preferred embodiment thereof, given by way of example only , reference being had to the accompanying drawings wherein :
Figure 1 is a schematic part sectional view of a preferred embodiment of the invention; and
Figures 2-4 are cross-sections taken respectively on the lines AA, BB, and CC of Figure 1.
The differential assembly as shown in Figure 1 is contained within a housing 5 and comprises an input shaft 2 adapted to receive rotary input from an appropriate prime mover by way of an input flange 1. The input shaft 2 carries a pinion 3 which is in mesh with a crown wheel 4 secured to an internally toothed ring gear 6. Hence, rotation of the input shaft 2 causes rotation of the ring gear 6 about an axis transverse to the axis of the input shaft .
Mounted within the ring gear are a pair of planetary gear sets 9, 10 each comprising four planetary gears mounted on a respective planetary gear carrier 7, 8. The gear carriers are internally splined for driving connection with respective output shafts 19, 20 and are held in spaced apart configuration by a central spacer 18.
Each planetary gear set has associated therewith a respective sun gear 11a, 12a and each sun gear carries a respective worm wheel 11 ,12. Appropriate bearings are provided for supporting all the rotating components within the casing of the differential .
Each worm gear wheel 11 , 12 is in mesh with a respective worm 31 , 33 of opposite hand, the worms 31 , 33 being keyed to rotate on respective shafts 30, 32 and carrying respective gears 27, 29 which are in mesh with a common gear 28 carried by a control shaft 37.
In use, if the control shaft 37 is held against rotation, the worms 31 and 33 will also be held against rotation and they in turn will hold the worm wheels-. 11 , 12 and with them the associated sun gears 11a, 12a . As a result, rotary movement of the ring gear 6 will cause the planetary gear sets to run around the fixed sun gears and drive the output shafts 19, 20 at equal speeds .
If differential rotation of the output shafts is required the control shaft 37 is rotated in the appropriate sense to rotate the gears 27, 29 and with them the worms 31 , 33 in the same direction. Because of the opposite hand of the worms this will result in oppositely directed rotation of the worm wheels 11,12 and the associated sun gears 11a, 12a . The effect of this will be to increase the rotational speed of one planetary gear set and reduce the rotational speed of the other planetary gear set, resulting in corresponding respective increases and decreases in the rotational speed of the output shafts 19, 20. As soon as the period of differential rotational speed is no longer required rotation of the control shaft 37 is stopped and the output shafts 19, 20 immediately return to rotation at the same speed.
The described differential assembly is particularly suitable for use in effecting steering of a vehicle of the type in which steering is effected by differential rotation of driving arrangements on opposite longitudinal sides of the vehicle. Such steering systems are used, for example, in civil engineering plant, for example tracked vehicles. In the context of such equipment the proposed differential unit offers significant advantages. A suitable actuator, for example a rotary hydraulic motor, can be connected to the control shaft 37 and used to effect the desired differential rotation of the output shafts 19, 20. Since rotation of the control shaft 37 simultaneously effects an increase in speed of rotation of one output shaft and a decrease in speed of rotation of the other output shaft, using the device for steering offers the advantage that the centre line of the vehicle remains on the centre line of the turning circle during steering operations. As an alternative to the use of a single control shaft 37, the shafts 30, 32 of the worms 31 , 33 may be directly coupled to suitable rotary actuators for example hydraulic motors . If separate actuators are provided for the worms, the actuators may be rotated in opposite directions to effect simultaneous increase and decrease of the rotational speed of the output shafts, or only one actuator need be operated, thereby effecting an increase or decrease in the speed of one output shaft .
As an alternative to the use of hydraulic actuators , mechanical means may be provided for rotating either a single control shaft 37, or separately and directly rotating the worm shafts 30, 32. For example, rotary power may be taken from a suitable power take-off point and applied via one or more torque converters to the shaft 37 or the shafts 30, 32.
It will be noted that because differential rotation of the output shafts ceases immediately rotation of the worms ceases, when the differential is used as a steering assembly the vehicle will resume straight line movement immediately rotation of the worms is ceased and it is not necessary to return the steering control mechanism to a central position in order to resume straight line steering.
Whilst of particular use as a differential steering mechanism, embodiments of the invention may be used in other vehicle applications, for example to achieve optimum power distribution between the drive wheels of a wheeled vehicle. Under these circumstances relatively high speed control of the worms would be required via suitable microprocessor control so that the rotational speeds of the output shafts would be matched to the particular requirements of the vehicle during, e. g. cornering or traversing undulating surfaces . By appropriate control , optimum conditions can be obtained consistent with . permanent drive to each driven wheel .
In a modified design the worm wheels 11 , 12 are replaced by respective bevel gears which mesh with a common pinion whereby rotation of the pinion will cause oppositely directed rotation of the bevel gears .
The above described differential assembly may be formed as a self contained unit, in which case the output shafts 19, 20 may be inserted after the differential unit itself has been secured in position. As an alternative, the differential unit may be incorporated within the gear box, e. g. of a transversely mounted motor car engine with drive to the ring gear being taken directly from the output of the vehicle gear box .

Claims

1. A device for driving a pair of output shafts from a common rotary input shaft and for permitting differential rotation of the output shafts relative to each other, the device comprising: means coupling the input shaft to a ring gear whereby the ring gear is rotated in response to rotation of the input shaft; two planetary gear sets, each in mesh with the ring gear and each having a respective planetary gear carrier for driving connection with a respective one of the output shafts; respective sun gears for each planetary gear set; and means for rotating one sun gear relative to the other sun gear to produce differential rotation of the output shafts .
2. A device according to claim 1 , wherein each sun gear is provided with a worm wheel , and each worm wheel has associated therewith a worm for rotating the worm wheel and with it the associated sun gear.
3. A device according to claim 2, wherein the worms each carry a gear wheel , and the gear wheels of the worms are in mesh with a common gear wheel whereby rotation of the common gear wheel simultaneously rotates the worms to produce oppositely directed rotation of the sun gears .
4. A device according to any preceding claim, wherein the ring gear is operable to rotate about an axis transverse to the axis of rotation of the input shaft.
5. A device according to claim 4, wherein a pinion is carried on said input shaft, and a crown wheel is secured to said ring gear, the pinion being in mesh with the crown wheel .
PCT/GB1991/000817 1990-05-25 1991-05-24 Differential drive assembly WO1991019117A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9011810.0 1990-05-25
GB909011810A GB9011810D0 (en) 1990-05-25 1990-05-25 Differential drive assembly

Publications (1)

Publication Number Publication Date
WO1991019117A1 true WO1991019117A1 (en) 1991-12-12

Family

ID=10676611

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1991/000817 WO1991019117A1 (en) 1990-05-25 1991-05-24 Differential drive assembly

Country Status (3)

Country Link
AU (1) AU7902491A (en)
GB (1) GB9011810D0 (en)
WO (1) WO1991019117A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100463829C (en) * 2007-04-30 2009-02-25 长安大学 Steering drive device for caterpillar vehicle

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB127187A (en) * 1918-11-13 1919-05-29 Caterpillar Tractors Ltd Improvements in and relating to Self-propelled Vehicles.
GB138475A (en) * 1919-03-21 1920-02-12 Richard Brennan Improvements in and connected with self propelled vehicles having all wheels coupledand in fixed relation to each other
DE734330C (en) * 1940-01-25 1943-04-14 Carl F W Borgward Steering device for half caterpillar vehicles
DE2736009A1 (en) * 1977-08-10 1979-02-22 Zahnradfabrik Friedrichshafen Steering system for endless tracked vehicles - has respective planetary gear trains combined into single unit offset from drive shaft
EP0304594A2 (en) * 1987-08-24 1989-03-01 Renk Aktiengesellschaft Electromechanical drive assembly for a track-laying vehicle

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB127187A (en) * 1918-11-13 1919-05-29 Caterpillar Tractors Ltd Improvements in and relating to Self-propelled Vehicles.
GB138475A (en) * 1919-03-21 1920-02-12 Richard Brennan Improvements in and connected with self propelled vehicles having all wheels coupledand in fixed relation to each other
DE734330C (en) * 1940-01-25 1943-04-14 Carl F W Borgward Steering device for half caterpillar vehicles
DE2736009A1 (en) * 1977-08-10 1979-02-22 Zahnradfabrik Friedrichshafen Steering system for endless tracked vehicles - has respective planetary gear trains combined into single unit offset from drive shaft
EP0304594A2 (en) * 1987-08-24 1989-03-01 Renk Aktiengesellschaft Electromechanical drive assembly for a track-laying vehicle

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100463829C (en) * 2007-04-30 2009-02-25 长安大学 Steering drive device for caterpillar vehicle

Also Published As

Publication number Publication date
AU7902491A (en) 1991-12-31
GB9011810D0 (en) 1990-07-18

Similar Documents

Publication Publication Date Title
US5390751A (en) Planetary steering system for a skid-steered vehicle
US5409425A (en) Torque distributing mechanism in differential
US7309300B2 (en) Electric drive system with plural motors
US5387161A (en) Torque distributing mechanism in differential
US4471669A (en) Track drive system with dual mode steering
US5176589A (en) Differential gear
US4998591A (en) Electro-mechanical drive system for a full-track vehicle
US7441613B2 (en) Electric drive system with differential steering
CN101041362B (en) A skid steered vehicle and drive configuration
ES2004231A6 (en) Driving and steering system.
US6656074B2 (en) Crawler vehicle transmission-steering assembly
US6554729B2 (en) Steer-drive for boats and planes
EP2125492B1 (en) Drive configuration for a skid steered vehicle
JPS6020621B2 (en) Device with planetary gears
US6454031B2 (en) Vehicle transmission apparatus
US9109687B1 (en) Differential system with a differential rate governed by an auxiliary electric motor and its associated method of operation
US5545098A (en) Compact steering apparatus
JPH06300096A (en) Torque distributing mechanism for differential gear
US4784232A (en) Transmission for a wheel- or tracktype vehicle comprising a braking device and a steering unit
JP2876376B2 (en) Differential torque distribution mechanism
WO1991019117A1 (en) Differential drive assembly
US5263905A (en) Arrangement for driving two wheels of the same axle in rotation, with a regulation of their rotational speeds
CN220320241U (en) Zero differential speed type double-flow transmission device
JP2593583Y2 (en) Vehicle steering system
JPH06297977A (en) Torque dividing mechanism for differential gear

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU BR JP SU US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LU NL SE