WO2020193976A1 - Seamless-shift transmission - Google Patents

Seamless-shift transmission Download PDF

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Publication number
WO2020193976A1
WO2020193976A1 PCT/GB2020/050802 GB2020050802W WO2020193976A1 WO 2020193976 A1 WO2020193976 A1 WO 2020193976A1 GB 2020050802 W GB2020050802 W GB 2020050802W WO 2020193976 A1 WO2020193976 A1 WO 2020193976A1
Authority
WO
WIPO (PCT)
Prior art keywords
input shaft
transmission
output shaft
shaft
gear
Prior art date
Application number
PCT/GB2020/050802
Other languages
French (fr)
Inventor
John Sutton
Alexander Fraser
Original Assignee
Mclaren Automotive Limited
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 Mclaren Automotive Limited filed Critical Mclaren Automotive Limited
Publication of WO2020193976A1 publication Critical patent/WO2020193976A1/en

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Classifications

    • 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
    • F16H3/00—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion
    • F16H3/006—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion power being selectively transmitted by either one of the parallel flow paths
    • 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
    • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
    • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
    • B60K6/22—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs
    • B60K6/38—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs characterised by the driveline clutches
    • B60K6/387—Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means
    • 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
    • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
    • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
    • B60K6/42—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by the architecture of the hybrid electric vehicle
    • B60K6/48—Parallel type
    • 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
    • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
    • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
    • B60K6/50—Architecture of the driveline characterised by arrangement or kind of transmission units
    • B60K6/54—Transmission for changing ratio
    • B60K6/547—Transmission for changing ratio the transmission being a stepped gearing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/02—Conjoint control of vehicle sub-units of different type or different function including control of driveline clutches
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/10—Conjoint control of vehicle sub-units of different type or different function including control of change-speed gearings
    • B60W10/11—Stepped gearings
    • B60W10/113—Stepped gearings with two input flow paths, e.g. double clutch transmission selection of one of the torque flow paths by the corresponding input clutch
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
    • B60W30/18—Propelling the vehicle
    • B60W30/19—Improvement of gear change, e.g. by synchronisation or smoothing gear shift
    • 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
    • F16H3/00—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion
    • F16H3/02—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion
    • F16H3/08—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion exclusively or essentially with continuously meshing gears, that can be disengaged from their shafts
    • F16H3/087—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion exclusively or essentially with continuously meshing gears, that can be disengaged from their shafts characterised by the disposition of the gears
    • F16H3/089—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion exclusively or essentially with continuously meshing gears, that can be disengaged from their shafts characterised by the disposition of the gears all of the meshing gears being supported by a pair of parallel shafts, one being the input shaft and the other the output shaft, there being no countershaft involved
    • 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
    • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
    • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
    • B60K6/42—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by the architecture of the hybrid electric vehicle
    • B60K6/48—Parallel type
    • B60K2006/4825—Electric machine connected or connectable to gearbox input shaft
    • 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
    • F16H3/00—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion
    • F16H3/006—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion power being selectively transmitted by either one of the parallel flow paths
    • F16H2003/007—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion power being selectively transmitted by either one of the parallel flow paths with two flow paths, one being directly connected to the input, the other being connected to the input though a clutch
    • 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
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/04—Smoothing ratio shift
    • F16H2061/0425—Bridging torque interruption
    • F16H2061/0433—Bridging torque interruption by torque supply with an electric motor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/62—Hybrid vehicles

Definitions

  • This invention relates to a transmission, particularly for use in hybrid vehicles and methods for using the same.
  • the performance of a transmission is of critical importance for both the driving performance of the vehicle and to the experience of a driver.
  • the transmission can affect almost all aspects of a vehicle’s performance, including acceleration, top speed, fuel economy, total weight and weight distribution.
  • AMTs automatic manual transmissions
  • DCTs dual-clutch transmissions
  • AMTs generally operate in a similar manner to conventional manual transmissions, however, the control of the clutch, gear selection and throttle during gear shifts may be automated.
  • Electronically controlled clutches are commonly used.
  • the gear shifts can be automatic and hence a clutch pedal is not required.
  • Transmissions that incorporate wet clutches can incur fluid drag losses and parasitic torque loss due to an engine driven pump.
  • DCTs include two separate clutches for odd and even gear sets.
  • the two clutches are usually contained within the same housing.
  • the odd and even gear sets each use a transmission similar to a conventional manual transmission.
  • DCTs contain a large number of independent shafts and require a large number (usually 4) actuator state changes per gear shift. These factors, along with the need for two clutches, can make DCTs large, heavy and expensive.
  • a transmission comprising: an output shaft (124); a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft; a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft; a second motor (112) configured to drive the second input shaft; a coupling mechanism (122) configured to controllably engage to positively connect the first and second input shafts.
  • the transmission may be capable of driving the output shaft in a first gear when the transmission is in a state in which the coupling mechanism is disengaged and the output shaft can be driven by a first wheel carried by the first input shaft.
  • the transmission may be capable of driving the output shaft in a first shifting mode when the transmission is in a state in which the output shaft can be driven by a first wheel carried by the second input shaft and a first wheel carried by the first input shaft.
  • the transmission may be capable of driving the output shaft in a second gear when the transmission is in a state in which the coupling mechanism is engaged and the output shaft can be driven by a first wheel carried by the second input shaft.
  • the first motor may be an electric motor and the second motor may be an internal combustion engine.
  • the transmission may be capable of operating in an engine start mode with the internal combustion engine inactive when the transmission is in a state in which the coupling mechanism is engaged such that the first input shaft can drive the second input shaft.
  • the transmission may be capable of operating in an electric generation mode when the transmission is in a state in which the coupling mechanism is engaged such that the second input shaft can drive the first input shaft.
  • the transmission may be capable of coupling the input and output shafts in four gears, the first gear having the lowest gear ratio of the four gears.
  • the first input shaft may carry wheels for driving the output shaft in the first gear and a third gear and the second input shaft may carry wheels for driving the output shaft in a second and fourth gear.
  • the wheels of the first and second input shafts may be gearwheels.
  • the first and second input shafts may be coaxial.
  • the transmission may comprise a clutch configured to controllably disconnect the second motor from the second input shaft.
  • the transmission may be capable of operating in a single engine mode with the second motor inactive when the coupling mechanism is engaged such that the first input shaft can drive the second input shaft.
  • Each of the first and second motors may be configured to provide additional torque when the other of the first and second motors is not driving the output shaft.
  • the transmission may further comprise one or more auxiliary motor(s) for providing torque to an auxiliary axle, the auxiliary motor(s) may be configured to provide additional torque: at a predetermined time during a gear shift; and/or if the torque provided by one or both of the first and second motors to the output shaft falls below a predetermined level.
  • a method of shifting from a first gear to a second gear in a transmission comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft, a second motor (112) configured to drive the second input shaft, the method comprising:
  • the method may further comprise, prior to driving the output shaft with the first wheel carried by the first input shaft and the first wheel carried by the second input shaft, driving the output shaft with just the first wheel carried by the first input shaft.
  • the method may further comprise, prior to positively connecting the first input shaft and the second input shaft, decreasing the speed of revolution of the first input shaft to match the speed of revolution of the second input shaft.
  • a method of shifting from a second gear to a first gear in a transmission comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft, a second motor (112) configured to drive the second input shaft, and wherein the first input shaft is initially positively connected to the second input shaft, the method
  • the method may further comprise, prior to driving the output shaft with the first wheel carried by the second input shaft and a first wheel carried by the first input shaft, increasing the speed of revolution of the first input shaft such that the first wheel carried by the first input shaft can drive the output shaft in a first gear.
  • a method of shifting from a second gear to a third gear in a transmission comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft, a second motor (112) configured to drive the second input shaft, and wherein the first input shaft is initially positively connected to the second input shaft; the method
  • the method may further comprise, prior to driving the output shaft with the first wheel carried by the second input shaft and a second wheel (108) carried by the first input shaft, decreasing the speed of revolution of the first input shaft to match the speed of revolution of the second input shaft.
  • the method may further comprise, prior to positively connecting the first input shaft and the second input shaft, decreasing the speed of revolution of the second input shaft to match the speed of revolution of the first input shaft.
  • the transmission further comprises a clutch (344) configured to controllably disconnect the second motor from the second input shaft, and the method may further comprise, prior to disconnecting the first wheel carried by the second input shaft from the output shaft, opening the clutch.
  • the method may further comprise, subsequent to positively connecting the first input shaft and the second input shaft, closing the clutch.
  • a method of shifting from a third gear to a second gear in a transmission comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft, a second motor (112) configured to drive the second input shaft, and wherein the first input shaft is initially positively connected to the second input shaft; the method
  • the method may further comprise, prior to driving the output shaft with a first wheel carried by the second input shaft and the second wheel carried by the first input shaft, increasing the speed of revolution of the second input shaft such that the first wheel carried by the second input shaft can drive the output shaft in a first gear.
  • the transmission further comprises a clutch (344) configured to controllably disconnect the second motor from the second input shaft, and the method may further comprise, prior to disconnecting the first input shaft and the second input shaft, opening the clutch.
  • the method may further comprise, subsequent to positively connecting the first input shaft and the second input shaft, closing the clutch.
  • Figure 1 shows a schematic view of an exemplary transmission 100.
  • Figure 2 shows a schematic view of exemplary transmission 100 in an engine start mode.
  • Figures 3 to 7 shows a schematic view of exemplary transmission 100 at various stages of the process of shifting from the first to a second gear.
  • Figure 8 shows an exemplary series of steps 200 for changing gear with
  • Figure 9A shows an exemplary plot of the rotational speed of each of the first and second motors 102 and 112 against the time/distance travelled for a vehicle containing transmission 100.
  • Figure 9B illustrates the state of a coupling mechanism 122 against the time/distance travelled for a vehicle containing transmission 100.
  • Figure 9C illustrates the state of locking devices 138, 140 and 142 against the time/distance travelled for a vehicle containing transmission 100.
  • Figure 10A shows an exemplary plot of the torque provided by each motor during two gear shifts against the time/distance travelled for a vehicle containing
  • Figure 10B illustrates the state of the coupling mechanism 122 against the time/distance travelled for a vehicle containing transmission 100 using the torque compensation shown by Figure 10A.
  • Figures 11 A and 11 B illustrate the torque profiles of a vehicle (from transmission 100) against the time/distance travelled for the vehicle.
  • Figure 12 shows a schematic view of an exemplary transmission 300 comprising a K0 clutch 344.
  • Figure 13 shows an exemplary series of steps 400 for changing from an even numbered gear to an odd numbered gear with transmission 300.
  • Figure 14 shows an exemplary series of steps 500 for changing from an odd numbered gear to an even numbered gear with transmission 300.
  • FIG. 1 illustrates an exemplary transmission 100.
  • the transmission 100 and associated methods will herein be primarily described using automotive terminology. However, the transmission 100 and associated methods may also be used in agricultural, industrial, construction, mining, electrical power generation, and other applications.
  • the transmission 100 comprises a first input shaft 104, a second input shaft 114 and an output shaft 124.
  • a first motor 102 is configured to drive the first input shaft 104.
  • a second motor 112 is configured to drive the second input shaft 114.
  • the output shaft 124 may deliver power to other components of a drivetrain. Examples of such other components include differentials, torque converters, front or rear axles, propeller shafts, and flywheels.
  • the first and second input shafts 104 and 114 may be coaxial or eccentric.
  • the first input shaft 104 may partially enclose the second input shaft 114.
  • the second input shaft 114 may partially enclose the first input shaft 104.
  • Figure 1 shows the first and second input shafts 104 and 114 in a coaxial arrangement with the first input shaft 104 partially enclosing the second input shaft 114.
  • the coaxial and enclosing arrangement shown is an advantageously compact arrangement.
  • Transmission 100 also comprises a coupling mechanism 122.
  • Coupling mechanism 122 is configured to controllably engage. Engaging the coupling mechanism 122 (i.e. closing the coupling) causes the first and second input shafts 104 and 114 to become positively connected.
  • the coupling mechanism 122 may comprise a dog/j aw/tooth/positive-contact clutch.
  • the coupling mechanism 122 may comprise a reduction gear.
  • the reduction gear may be an epicyclic/planetary gear. Hence, positive connection should not be understood to imply that a 1 : 1 gear ratio is required.
  • the first input shaft 104 carries one or more wheels 106, 108, 110.
  • the second input shaft 114 carries one or more wheels 116, 118, 120.
  • Each wheel on one shaft may be configured to engage a corresponding wheel on the output shaft 124 so as to drive it to rotate or be driven by it to rotate.
  • the engagement may be positive contact (as in the engagement between two gear wheels) or frictional (as in the engagement of two smooth-surfaced wheels).
  • Examples of such positive contact wheels include gears such as spur gears, helical gears, bevel gears, miter gears, screw gears, worm gears.
  • friction wheels include pulley wheels, and elastomeric or rubber wheels.
  • the term‘wheel’ should not be understood to denote size/diameter.
  • the wheels may alternatively be referred to as pinions.
  • the output shaft 124 carries wheels 126, 128, 130, 132, 134 and 136. Wheels 126, 128, 130, 132, 134 and 136 can be rotationally fixed to or rotationally freed from the output shaft by a locking device. Each wheel on the output shaft 124 may be configured to engage a corresponding wheel on the first and second input shafts 104, 114 so as to drive or be driven by it. As will be described in detail below, a wheel on each of the first and second input shafts 104, 114 may simultaneously engage with corresponding wheels on the output shaft 124 so as to drive the output shaft 124. Transmission 100 is shown with three locking devices 138, 140 and 142.
  • Each locking device is actuatable to rotationally fix or free at least one respective wheel 126, 128, 130, 132, 134 and 136 to or from the output shaft 124.
  • Each locking device may be actuatable to rotationally fix or free two wheels to or from the output shaft, as in the example shown in Figure 1.
  • the locking device may comprise a collar that wholly or partly excircles the output shaft 124.
  • One of wheels 126 and 136 can be rotationally fixed to or rotationally freed from the output shaft 124 by actuating a locking device 138.
  • One of wheels 132 and 134 can be rotationally fixed to or rotationally freed from the output shaft 124 by actuating a locking device 140.
  • One of wheels 128 and 130 can be rotationally fixed to or rotationally freed from the output shaft 124 by actuating a locking device 142.
  • Locking devices 138, 140 and 142 may each comprise a synchroniser.
  • locking devices 138, 140 and 142 comprise a synchroniser
  • the locking devices 138, 140 and 142 and associated wheels 126, 128, 130, 132, 134 and 136 may form a synchromesh arrangement.
  • the neutral (i.e. not actuated/activated) position of each of the locking devices 138, 140, 142 is such that none of wheels 126, 128, 130, 132,
  • First gear will generally have the lowest gear ratio, followed by second, then third etc.
  • Transmission 100 has at least 2 gear ratios (or driving gears). Transmission 100 may have three, four, five, six, seven, eight, or more gear ratios. Each wheel carried by the first and second input shafts 104, 114 may drive the output shaft in a different gear ratio. Each gear ratio is dictated by the relative size of a wheel carried by the output shaft 124 and a corresponding wheel carried by the first or second input shaft 104, 114.
  • the first motor 102 is an electric motor and the second motor 112 is an internal combustion engine (ICE).
  • the first and second motors 102 and 112 may each be an electric motor.
  • FIG. 2 shows a mode of operation wherein the power from one motor is fed to the other motor.
  • the flow of power through the transmission 100 is shown by the dotted arrows.
  • the coupling mechanism 122 is engaged and none of the locking devices 138, 140 and 142 are actuated.
  • the first motor 102 drives the first input shaft 104 which in turn drives the second input shaft 114 via the coupling mechanism 122.
  • the second input shaft 114 then drives the second motor 112.
  • an electric motor may act as a starter motor for an internal combustion engine. This mode of operation may be referred to as the engine start mode.
  • the second motor 112 may provide power to the first motor 102 (i.e. the direction of the dotted arrows may be reversed).
  • an internal combustion engine can drive an electric motor such that the electric motor acts as a generator.
  • the power of the internal combustion engine may thereby be used to charge batteries. This mode of operation may be referred to as the electric generation mode.
  • the first and second motor 102 and 112 may operate independently.
  • the six-gear example shown in Figures 1 to 7, is capable of being driven in a three-gear mode powered solely by the first motor 102 or in a three-gear mode powered solely by the second motor 112.
  • the transmission 100 is capable of being driven in all gears powered solely by the first or second motor 102, 112 when the coupling 122 is closed and the other of the first or second motor 102, 112 is allowed to rotate freely.
  • Figure 3 shows the transmission 100 being driven in a first gear.
  • the first motor 102 drives the first input shaft 104.
  • Locking device 138 is actuated such that the output shaft 124 may be driven by the first input shaft via wheels 106 and 126.
  • an electric motor to drive the output shaft in the first gear as electric motors can provide the initial power required without the need for a starting/pull-away clutch.
  • the transmission may operate in an electric launching mode.
  • using an electric motor in the first gear allows the internal combustion engine to be deactivated whilst a vehicle is stationary, saving fuel that would otherwise be used to keep the combustion engine in its idle state.
  • Figure 9A shows an exemplary plot of the rotational speed of each of the first and second motors 102 and 112 against the time/distance travelled for a vehicle containing transmission 100.
  • References to speed shall herein refer to rotational speed, unless otherwise labelled as vehicle speed or linear speed.
  • the first motor 102 is an electric motor and the second motor 112 is an internal combustion engine.
  • the line corresponding to the first motor 102 passes through the origin as, in the first gear, when the speed of the first motor is zero, the vehicle speed will be zero.
  • the line corresponding to the second motor 112 does not pass through the origin as the internal combustion second motor 112 will have a minimum speed, NICE idle , below which the second motor 112 would stall.
  • the circled numbers 1 to 6 denote the conventional driving gear associated with each region of the plot.
  • the gradients of the lines (which should correspond to the gear ratio) are not represented accurately for simplicity.
  • the first region (1 ), generally corresponds to the first gear discussed above in relation to Figure 3.
  • the speed of the first motor 102 increases from zero linearly with vehicle speed.
  • the speed of the second motor 112 is represented with a dashed line. This is to indicate that the second motor need not contribute any power. However, if more power is required, for example, if a greater acceleration is required, the second motor 112 may contribute power.
  • the second motor 112 matches the speed of the first motor 102. Various examples of when this may occur are illustrated by the dashed lines in Figure 9A.
  • the speed of the second motor 1 12 substantially matches that of the first motor 102 as soon as the first motor reaches NICE IDLE Coupling mechanism 122 may then be engaged at any point. Once coupling mechanism 122 is engaged, the second motor 112 may contribute power.
  • the transmission 100 will be referred to as being in a combined drive mode when both the first and second motor 102 and 1 12 contribute power.
  • the second motor 1 12 remains at NICE IDLE until it is required to contribute power.
  • the second motor 1 12 When the second motor 1 12 is required to contribute power, it increases its speed to match that of the first motor 102. Once the speeds of the motors 102 and 112 are substantially equal, the coupling mechanism 122 may be engaged. Once coupling mechanism 122 is engaged, the second motor 1 12 may contribute power in a combined drive mode.
  • Figure 9B illustrates the state of the coupling mechanism 122.
  • the coupling mechanism 122 will generally be open in the first gear, as described above with reference to Figure 3.
  • the coupling mechanism 122 may engage/close to enter the combined drive mode as described above with reference to Figure 9A.
  • the combined drive mode options in region (1 ) in Figure 9B are shown with dashed lines, corresponding to the dashed lines in Figure 9A.
  • the transmission 100 may enter a combined drive mode at any point in region 1 (i.e. in a first gear), provided the speed of the first motor 102 is above NICE IDLE
  • FIG. 9C illustrates the state of locking devices 138, 140 and 142. As discussed above, each locking device 138, 140 and 142 may be in one of three positions.
  • Locking device 138 may fix wheel 126 to the output shaft 124 (labelled 1 ,
  • Locking device 140 may fix wheel 132 to the output shaft 124 (labelled 2,
  • Locking device 142 may fix wheel 128 to the output shaft 124 (labelled 3,
  • Figure 8 shows an exemplary series of steps 200 for changing up a gear, i.e. from gear X to gear X+1. This process will now be described with reference to Figures 3 to 7 which show the configuration of the transmission 100 at various stages of the process of shifting from the first to a second gear. In particular, the transition from region (1 ) to region (2) will be described by way of example.
  • the transmission 100 may be in a combined drive mode.
  • the first step 202 is therefore to determine whether the transmission 100 is or is not in a combined drive (CD) mode. If the transmission 100 is in a combined drive mode, the coupling mechanism 122 is disengaged/opened at step 204. If the transmission is not in a combined drive mode, step 204 can be skipped as the coupling mechanism 122 will already be disengaged. In the example of shifting from first to second gear, the transmission 100 will now be in the configuration shown in Figure 3.
  • CD combined drive
  • step 206 the input shaft which is not driving the output shaft in gear X reaches a speed suitable for driving the output shaft in the desired next gear, X+1.
  • Figure 4 shows an exemplary configuration of the transmission 100 during step 206 of shifting from first to second gear.
  • the second motor 112 reaches a speed suitable for driving the output shaft 124 in a second gear.
  • the dashed line in Figure 9A shows the second motor 104 reaching a speed suitable for driving the output shaft 124 in a second gear.
  • the second motor 104 reaching a speed suitable for diving the output shaft 124 in a second gear corresponds to where the dashed line transitions to a solid line on the right hand side of region (1 ).
  • the suitable speed is that at which wheel 116 can drive wheel 132 at a speed that substantially matches that of the output shaft 124.
  • the second motor 112 is not yet driving the output shaft 124 as locking device 140 is in the neutral position.
  • Locking device 140 is shown in the neutral position in the middle line of Figure 9C in region (1 ).
  • step 208 the input shaft which reached a suitable speed in the previous step is coupled to output shaft 124 by the actuation of the appropriate locking device.
  • Figure 5 shows an exemplary configuration of transmission 100 after step 208 has been performed during the shift from first gear to second gear.
  • Locking device 140 has been actuated to fix wheel 132 to the output shaft 124.
  • the output shaft 124 is thus coupled to both the first and second motors 102 and 112.
  • the actuation of locking device 140 from a neutral position when shifting from first to second gear is shown by the transition of the middle line in Figure 9C from N to 2.
  • step 210 the input shaft which has been driving the output shaft 124 in gear X is decoupled from the output shaft 124 by the appropriate locking device returning to a neutral position.
  • the transmission is in gear X+1 but further steps may be performed.
  • Figure 6 shows an exemplary configuration of the transmission 100 after step 210 has been performed during the shift from first gear to second gear.
  • Locking device 138 returns to its neutral position, decoupling the first input shaft 104 and wheels 106 and 126 from the output shaft 124. From this point, the transmission is operating fully in second gear.
  • the return of locking device 138 to a neutral position is shown by the transition of the top line in Figure 9C from 1 to N.
  • step 212 it is determined whether or not the transmission should enter a combined drive mode. If combined drive mode is not requested, then no further steps are taken and the transmission 100 is driven by one of the two motors. If combined drive mode is requested, then step 214 is performed. In step 214, the input shaft which is not driving the output shaft in gear X+1 is slowed to reach a speed suitable for driving the output shaft in gear X+1. The suitable speed is that which substantially matches that of the other input shaft.
  • This slowing may be performed actively. Examples of such active slowing include applying a friction brake and applying electromagnetic braking. The slowing may be allowed to occur passively through resistive forces.
  • FIG. 7 shows an exemplary configuration of the transmission 100 after step 216.
  • the transmission 100 may now operate in a combined drive mode.
  • the engagement of the coupling mechanism 122 when entering a combined drive mode in second gear is shown in Figure 9B as entering a closed state towards the end of region (1 ). Shifting down
  • the transmission 100 may be in combined drive mode in second gear, as described above with reference to Figure 7.
  • the transmission 100 may however be driven solely by the second motor 112.
  • the first step 202 is therefore to determine whether the transmission 100 is or is not in a combined drive (CD) mode. If the transmission 100 is in a combined drive mode, the coupling mechanism 122 is disengaged at step 204. If the transmission is not in a combined drive mode, step 204 can be skipped as the coupling mechanism 122 will already be disengaged. In the example of shifting from second to first gear, the transmission 100 will now be in the configuration shown in Figure 6.
  • CD combined drive
  • step 206 the input shaft which is not driving the output shaft in gear X reaches a speed suitable for driving the output shaft in the desired next gear, X-1.
  • Figure 6 shows an exemplary configuration of the transmission 100 during step 206 of shifting from second to first gear.
  • the first motor 102 reaches a speed suitable for driving the output shaft 124 in a first gear.
  • the suitable speed is that at which wheel 106 can drive wheel 126 at a speed that substantially matches that of the output shaft 124.
  • the first motor 102 is not yet driving the output shaft 124 as locking device 138 is in the neutral position. Locking device 138 is shown in the neutral position in the top line of Figure 9C in region (2).
  • step 208 the input shaft which reached a suitable speed in the previous step is coupled to output shaft 124 by the actuation of the appropriate locking device.
  • Figure 5 shows an exemplary configuration of transmission 100 after step 208 has been performed during the shift from second gear to first gear.
  • Locking device 138 has been actuated to fix wheel 126 to the output shaft 124.
  • the output shaft 124 is thus coupled to both the first and second motors 102 and 112.
  • the actuation of locking device 138 from a neutral position when shifting from second to first gear is shown by the transition of the top line in Figure 9C from N to 1.
  • step 210 the input shaft which has been driving the output shaft 124 in gear X is decoupled from the output shaft 124 by the appropriate locking device returning to a neutral position.
  • the transmission is in gear X-1 but further steps may be performed.
  • Figure 4 shows an exemplary configuration of the transmission 100 after step 210 has been performed during the shift from second gear to first gear.
  • Locking device 140 returns to its neutral position, decoupling the second input shaft 114 and wheels 116 and 132 from the output shaft 124. From this point, the transmission is operating fully in first gear.
  • the return of locking device 140 to a neutral position is shown by the transition of the middle line in Figure 9C from 2 to N.
  • step 212 it is determined whether or not the transmission should enter a combined drive mode. If combined drive mode is not requested, then no further steps are taken and the transmission 100 is driven by one of the two motors. If combined drive mode is requested, then step 214 is performed. In step 214, the input shaft which is not driving the output shaft in gear X-1 is adjusted to reach a speed suitable for driving the output shaft in gear X-1. The suitable speed is that which substantially matches that of the other input shaft.
  • the coupling mechanism 122 is then engaged in step 216 so as to positively connect the first and second input shafts 104 and 114.
  • the transmission 100 may now operate in a combined drive mode.
  • the engagement of the coupling mechanism 122 when entering a combined drive mode in first gear is shown in Figure 9B as the dotted lines remaining in a closed state in region (1 ).
  • the transmission 100 as described above may provide several advantages over existing systems.
  • the two motors 102 and 112 enable the transmission 100 to operate using only one of the two motors, in an electric driving mode or an internal combustion driving mode.
  • the transmission 100 may operate in an alternating motor mode.
  • the output shaft 124 may be driven solely by the first motor 102 in gears one, three and five, and may be driven solely by the second motor 112 in gears two, four and six.
  • the transmission 100 may also operate in a three-gear mode powered solely by the first motor 102 or in a three-gear mode powered solely by the second motor 112. These operational modes provide redundancy in the event that a motor and/or its associated gearing malfunctions. For example, if the second motor 112 malfunctions the transmission 100 may operate in a three-gear mode powered solely by the first motor 102. Though powering the output shaft 124 with a single motor provides less power than utilising the combined drive capability, the option to only use one motor provides great flexibility.
  • the use of an electric motor as the first motor 102 allows the transmission 100 to accelerate a vehicle from a stop and travel at low speeds solely under electric power. This can allow the second motor 112 to be turned off at low speeds, saving electrical charge or fuel.
  • Transmission 100 may also operate without a clutch when the first motor 102 comprises an electric motor.
  • a clutch-free configuration requires fewer parts, thus reducing the weight and cost of the system. The savings in weight and cost are particularly pronounced over dual clutch systems.
  • the lack of a clutch eliminates the fluid drag losses that would be caused by a wet clutch.
  • the lack of a wet clutch also removes the necessity for an engine driven high-pressure oil pump, thus reducing parasitic torque loss.
  • Transmission 100 allows for gear shifting to occur without substantial loss of torque. Torque loss during a gear shift is reduced as a consequence of at least one motor is driving the output shaft 124 at all times. Maximum torque is provided when the transmission 100 operates in combined drive mode. Thus, when only one motor is driving the output shaft 124, maximum torque is not provided. An example of when maximum torque is not provided is between steps 204 and 216 when the coupling mechanism 122 is disengaged. Such a drop in torque may be noticeable to a driver and may affect the driving experience. Flence further improvements to the system can be made to improve the driving experience.
  • FIG. 10A An exemplary plot of the torque provided by each motor is shown in Figure 10A.
  • Figure 10A shows two exemplary gear shifts, the shift from third gear to fourth gear and the shift from fourth gear to fifth gear.
  • the torque of the first motor 102 is shown with a solid line and the torque of the second motor 112 is shown with a dashed line.
  • the motors In between gear shifts the motors each operate at a torque Ti. Ti is lower than the maximum torque that each motor is able to provide.
  • the first motor 102 initially provides a higher level of torque T2 to compensate for the second motor 112 being disconnected from the output shaft 124 and providing zero torque at step 204 of the method described above.
  • the disengaging of the coupling mechanism 122 in step 204 is shown as the transition from closed to open in Figure 10B.
  • the second motor 112 provides the higher level of torque T2 to compensate for the first motor 102 providing zero torque.
  • the engaging of the coupling mechanism 122 in step 210 is shown as the transition from open to closed in Figure 10B.
  • the torque compensation method shown in Figures 10A and 10B prevents a noticeable drop in torque when the motors are not providing their maximum torque when a gear shift is initiated. Examples of situations when the motors may not be providing their maximum torque when a gear shift is initiated include: when the driver is not fully depressing the accelerator pedal, and when the motors are limited so as not to provide their maximum torque between gear shifts (though this would negatively affect the overall driving performance).
  • the transmission 100 is used to power a first axle, one or more auxiliary motor(s) may power a second axle.
  • the first axle will be assumed to be a rear axle of a vehicle and the second axle will be assumed to be a front axle of a vehicle.
  • FIGS 1 1 A and 1 1 B show the torque profile of the vehicle, TTOTAL.
  • TTOTAL is the combination of the torque provided at the rear axle (from transmission 1 00), TREAR, and the torque provided at the front axle (from the one or more auxiliary motor(s)), TFRONT.
  • TREAR is a combination of the torque provided by the first motor 102 and the second motor 112.
  • the combined torque provided by the first and second motors 102, 112 are shown with the dotted and dashed lines in Figures 11A and 11 B.
  • the dotted line represents the torque provided by the outgoing gear (i.e. the gear you are shifting from).
  • the dashed line represents the torque provided by the ongoing gear (i.e. the gear you are shifting to).
  • FIG 11A shows the torque profile when the transmission 100 operates according to the torque compensation method described above with reference to Figures 10A and 10B.
  • TTOTAL can remain constant by making use of the torque compensation method.
  • the torque compensation method may only be used in situations where each motor is providing less than its maximum torque.
  • Figure 11 B shows a solution to the loss of rear-axle torque suffered when driving at higher total torque levels that takes advantage of the auxiliary motor(s) on the front axle.
  • the auxiliary motor(s) may increase its torque output during a gear shift. This is shown by the spike in TFRONT. This method may be used even when the rear motors are providing their maximum torque. Thus, the drop in torque from the rear motors during a gear shift can be compensated for by an increase in torque on the front axle.
  • the auxiliary motor(s) may be configured to provide additional torque at a predetermined time during a gear shift. Additionally or alternatively, the auxiliary motor(s) may be configured to provide additional torque when the torque provided by one or both of the first and second motors to output shaft falls below a predetermined level.
  • the transmission may further comprise a clutch for disconnecting the second motor.
  • Figure 12 shows an exemplary transmission 300 of the kind described above, further comprising a clutch 344 for disconnecting the second motor 312 from the second input shaft 314.
  • Clutch 344 may be referred to as a KO clutch.
  • KO clutch 344 is closed in its default state. When KO clutch 344 is opened, the second motor 312 is disconnected from the second input shaft 314, and thus from remainder of the transmission 300.
  • K0 clutch 344 When K0 clutch 344 is closed, the second motor 312 may drive the entirety of the second input shaft 314.
  • K0 clutch 344 may be a wet clutch or a dry clutch.
  • K0 clutch 344 may be a low inertia dry clutch in order to reduce weight, inertia, resistive losses and parasitic torque loss.
  • the K0 clutch may operate differently depending on whether the transmission 300 is shifting from an even numbered gear to an odd numbered gear, or vice versa.
  • Figure 13 shows an exemplary series of steps 400 for the operation of the K0 clutch 344 when shifting from an even numbered gear to an odd numbered gear. These steps may replace steps 210 to 216 shown in Figure 8 during a gear shift. For example, steps 400 may replace steps 210 to 216 when shifting from second to third gear or fourth to fifth gear.
  • the K0 clutch 344 is opened at step 402.
  • step 403 the second input shaft 314 is decoupled from the output shaft 324 by the appropriate locking device 338 or 340 returning to a neutral position.
  • step 404 it is determined whether or not the transmission should enter a combined drive mode. If combined drive mode is not requested, then the K0 clutch is closed at step 408 and the transmission 300 is driven solely by the first motor 302.
  • the coupling mechanism 322 is then engaged in step 406 so as to positively connect the first and second input shafts 304 and 314.
  • the KO clutch is closed at step 410 and the transmission 300 is driven by the first and second motors 302 and 312.
  • Figure 14 shows an exemplary series of steps 500 for the operation of the K0 clutch 344 when shifting from an odd numbered gear to an even numbered gear. These steps may replace steps 202 to 208 shown in Figure 8 during a shift from, for example, first to second gear, third to fourth gear, or fifth to sixth gear.
  • step 501 the K0 clutch 344 is opened.
  • step 502 it is determined whether the transmission 300 is or is not in a combined drive mode. If the transmission 300 is in a combined drive mode, the coupling mechanism 322 is disengaged/opened at step 504. If the transmission is not in a combined drive mode, step 504 can be skipped as the coupling mechanism 322 will already be disengaged.
  • step 506 the second input shaft 314 is coupled to output shaft 324 by the actuation of the appropriate locking device 338 or 340.
  • the K0 clutch is then closed in step 507 and the remaining method steps 210 and 212 (and possibly 214 and 216 depending on the decision at step 212) can be completed as described in relation to Figure 8.
  • the moment of inertia of the engine is relatively high. Opening the K0 clutch 344 decreases the moment of inertial associated with the second input shaft 314. Opening the K0 clutch 344 also removes any binding torque generated by the second motor 312. This reduction in inertia and binding torque allows coupling mechanism 322 and locking mechanisms 338 and 340 to be engaged and disengaged more easily/readily.
  • the K0 clutch 344 can improve the speed gradient of the second motor 312.
  • the speed gradient is the rate at which the motor can slow down, i.e. the gradient of the downslope between gears in Figure 9A.
  • Disconnecting the engine allows the second input shaft 314 to slow down quicker due to the relatively low moment of inertia of the second input shaft 314. This allows the coupling mechanism 322, as well as locking mechanisms 338 and 340 to engage sooner and thus the gear shift to complete sooner.
  • the reduced inertia also makes engaging the locking mechanisms 338, 340 easier.
  • the second input shaft 314 need not be slowed down when operating according to methods 400 and 500. It should be noted that the input shaft slowing step 214 is omitted from method 400. Similarly, the input shaft slowing step 206 is omitted from method 500. The rotation of the second input shaft 314 may be sped up instead.
  • the second motor 312 may provide a burst of power to the transmission 300. This power may be used to give an additional launch by providing a brief period of increased acceleration. Additionally or alternatively some of this power may be absorbed by an electric first motor 302.
  • the K0 clutch 344 also provides further functionality beyond the improved gear shifting described above. By opening the K0 clutch 344, the transmission 300 is able to drive in each gear, powered by the first motor 302 alone.
  • the K0 clutch 344 may be used to assist in launch so as to facilitate a range of regimes in which the vehicle can set off from rest.
  • the second motor 312 can assist in launch, to provide an additional or alternative power source to the transmission. This is in contrast to the electric launching mode described above that solely uses the first motor 102/312.
  • the K0 clutch 344 can also be used to disconnect the second motor 312 in the event that the second motor 312 fails. This provides an additional safety precaution and can prevent a malfunction in the second motor 312 from damaging the rest of transmission 300. Similarly, a malfunction in the rest of the transmission 300 can be prevented from damaging the second motor 312.

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Abstract

A transmission (100) comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft, a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 20) for driving the output shaft, a second motor (112) configured to drive the second input shaft, a coupling mechanism (122) configured to controllably engage to positively connect the first and second input shafts.

Description

SEAMLESS-SHIFT TRANSMISSION
FIELD
This invention relates to a transmission, particularly for use in hybrid vehicles and methods for using the same.
BACKGROUND
The performance of a transmission is of critical importance for both the driving performance of the vehicle and to the experience of a driver. The transmission can affect almost all aspects of a vehicle’s performance, including acceleration, top speed, fuel economy, total weight and weight distribution.
Existing systems include automatic manual transmissions (AMTs) and dual-clutch transmissions (DCTs).
AMTs generally operate in a similar manner to conventional manual transmissions, however, the control of the clutch, gear selection and throttle during gear shifts may be automated. Electronically controlled clutches are commonly used. The gear shifts can be automatic and hence a clutch pedal is not required. Transmissions that incorporate wet clutches can incur fluid drag losses and parasitic torque loss due to an engine driven pump.
DCTs include two separate clutches for odd and even gear sets. The two clutches are usually contained within the same housing. The odd and even gear sets each use a transmission similar to a conventional manual transmission. DCTs contain a large number of independent shafts and require a large number (usually 4) actuator state changes per gear shift. These factors, along with the need for two clutches, can make DCTs large, heavy and expensive.
There is a need for an improved transmission that addresses these problems. SUMMARY OF THE INVENTION
According to the present invention there is provided a transmission (100) comprising: an output shaft (124); a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft; a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft; a second motor (112) configured to drive the second input shaft; a coupling mechanism (122) configured to controllably engage to positively connect the first and second input shafts.
The transmission may be capable of driving the output shaft in a first gear when the transmission is in a state in which the coupling mechanism is disengaged and the output shaft can be driven by a first wheel carried by the first input shaft.
The transmission may be capable of driving the output shaft in a first shifting mode when the transmission is in a state in which the output shaft can be driven by a first wheel carried by the second input shaft and a first wheel carried by the first input shaft.
The transmission may be capable of driving the output shaft in a second gear when the transmission is in a state in which the coupling mechanism is engaged and the output shaft can be driven by a first wheel carried by the second input shaft.
The first motor may be an electric motor and the second motor may be an internal combustion engine.
The transmission may be capable of operating in an engine start mode with the internal combustion engine inactive when the transmission is in a state in which the coupling mechanism is engaged such that the first input shaft can drive the second input shaft. The transmission may be capable of operating in an electric generation mode when the transmission is in a state in which the coupling mechanism is engaged such that the second input shaft can drive the first input shaft.
The transmission may be capable of coupling the input and output shafts in four gears, the first gear having the lowest gear ratio of the four gears.
The first input shaft may carry wheels for driving the output shaft in the first gear and a third gear and the second input shaft may carry wheels for driving the output shaft in a second and fourth gear.
The wheels of the first and second input shafts may be gearwheels.
The first and second input shafts may be coaxial.
The transmission may comprise a clutch configured to controllably disconnect the second motor from the second input shaft.
The transmission may be capable of operating in a single engine mode with the second motor inactive when the coupling mechanism is engaged such that the first input shaft can drive the second input shaft.
Each of the first and second motors may be configured to provide additional torque when the other of the first and second motors is not driving the output shaft.
The transmission may further comprise one or more auxiliary motor(s) for providing torque to an auxiliary axle, the auxiliary motor(s) may be configured to provide additional torque: at a predetermined time during a gear shift; and/or if the torque provided by one or both of the first and second motors to the output shaft falls below a predetermined level.
There is also provided a method of shifting from a first gear to a second gear in a transmission (100), the transmission comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft, a second motor (112) configured to drive the second input shaft, the method comprising:
driving the output shaft with a first wheel (106) carried by the first input shaft and a first wheel (116) carried by the second input shaft; disconnecting the first wheel carried by the first input shaft from the output shaft; and positively connecting the first input shaft and the second input shaft.
The method may further comprise, prior to driving the output shaft with the first wheel carried by the first input shaft and the first wheel carried by the second input shaft, driving the output shaft with just the first wheel carried by the first input shaft.
The method may further comprise, prior to positively connecting the first input shaft and the second input shaft, decreasing the speed of revolution of the first input shaft to match the speed of revolution of the second input shaft.
There is also provided a method of shifting from a second gear to a first gear in a transmission (100), the transmission comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft, a second motor (112) configured to drive the second input shaft, and wherein the first input shaft is initially positively connected to the second input shaft, the method
comprising: driving the output shaft with a first wheel (116) carried by the second input shaft; disconnecting the first input shaft and the second input shaft; driving the output shaft with the first wheel carried by the second input shaft and a first wheel (106) carried by the first input shaft; and disconnecting the first wheel carried by the second input shaft from the output shaft.
The method may further comprise, prior to driving the output shaft with the first wheel carried by the second input shaft and a first wheel carried by the first input shaft, increasing the speed of revolution of the first input shaft such that the first wheel carried by the first input shaft can drive the output shaft in a first gear. There is also provided a method of shifting from a second gear to a third gear in a transmission (100), the transmission comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft, a second motor (112) configured to drive the second input shaft, and wherein the first input shaft is initially positively connected to the second input shaft; the method
comprising: driving the output shaft with a first wheel (116) carried by the second input shaft; disconnecting the first input shaft and the second input shaft; driving the output shaft with the first wheel carried by the second input shaft and a second wheel (108) carried by the first input shaft; disconnecting the first wheel carried by the second input shaft from the output shaft; and positively connecting the first input shaft and the second input shaft.
The method may further comprise, prior to driving the output shaft with the first wheel carried by the second input shaft and a second wheel (108) carried by the first input shaft, decreasing the speed of revolution of the first input shaft to match the speed of revolution of the second input shaft.
The method may further comprise, prior to positively connecting the first input shaft and the second input shaft, decreasing the speed of revolution of the second input shaft to match the speed of revolution of the first input shaft.
The transmission further comprises a clutch (344) configured to controllably disconnect the second motor from the second input shaft, and the method may further comprise, prior to disconnecting the first wheel carried by the second input shaft from the output shaft, opening the clutch.
The method may further comprise, subsequent to positively connecting the first input shaft and the second input shaft, closing the clutch.
There is also provided a method of shifting from a third gear to a second gear in a transmission (100), the transmission comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft, a second motor (112) configured to drive the second input shaft, and wherein the first input shaft is initially positively connected to the second input shaft; the method
comprising: driving the output shaft with a second wheel (128) carried by the first input shaft; disconnecting the first input shaft and the second input shaft; driving the output shaft with a first wheel (116) carried by the second input shaft and the second wheel (108) carried by the first input shaft; disconnecting the first wheel carried by the second input shaft from the output shaft; and positively connecting the first input shaft and the second input shaft.
The method may further comprise, prior to driving the output shaft with a first wheel carried by the second input shaft and the second wheel carried by the first input shaft, increasing the speed of revolution of the second input shaft such that the first wheel carried by the second input shaft can drive the output shaft in a first gear.
The transmission further comprises a clutch (344) configured to controllably disconnect the second motor from the second input shaft, and the method may further comprise, prior to disconnecting the first input shaft and the second input shaft, opening the clutch.
The method may further comprise, subsequent to positively connecting the first input shaft and the second input shaft, closing the clutch.
DESCRIPTION OF THE DRAWINGS
The present invention will now be described by way of example with reference to the accompanying drawings. In the drawings:
Figure 1 shows a schematic view of an exemplary transmission 100.
Figure 2 shows a schematic view of exemplary transmission 100 in an engine start mode. Figures 3 to 7 shows a schematic view of exemplary transmission 100 at various stages of the process of shifting from the first to a second gear.
Figure 8 shows an exemplary series of steps 200 for changing gear with
transmission 100.
Figure 9A shows an exemplary plot of the rotational speed of each of the first and second motors 102 and 112 against the time/distance travelled for a vehicle containing transmission 100.
Figure 9B illustrates the state of a coupling mechanism 122 against the time/distance travelled for a vehicle containing transmission 100.
Figure 9C illustrates the state of locking devices 138, 140 and 142 against the time/distance travelled for a vehicle containing transmission 100.
Figure 10A shows an exemplary plot of the torque provided by each motor during two gear shifts against the time/distance travelled for a vehicle containing
transmission 100.
Figure 10B illustrates the state of the coupling mechanism 122 against the time/distance travelled for a vehicle containing transmission 100 using the torque compensation shown by Figure 10A.
Figures 11 A and 11 B illustrate the torque profiles of a vehicle (from transmission 100) against the time/distance travelled for the vehicle.
Figure 12 shows a schematic view of an exemplary transmission 300 comprising a K0 clutch 344.
Figure 13 shows an exemplary series of steps 400 for changing from an even numbered gear to an odd numbered gear with transmission 300. Figure 14 shows an exemplary series of steps 500 for changing from an odd numbered gear to an even numbered gear with transmission 300.
DETAILED DESCRIPTION
The following description is presented to enable any person skilled in the art to make and use the invention and is provided in the context of a particular application.
Various possible modifications to the disclosed embodiments will be readily apparent to those skilled in the art.
The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and features disclosed herein.
Figure 1 illustrates an exemplary transmission 100. The transmission 100 and associated methods will herein be primarily described using automotive terminology. However, the transmission 100 and associated methods may also be used in agricultural, industrial, construction, mining, electrical power generation, and other applications.
The transmission 100 comprises a first input shaft 104, a second input shaft 114 and an output shaft 124. A first motor 102 is configured to drive the first input shaft 104. A second motor 112 is configured to drive the second input shaft 114. The output shaft 124 may deliver power to other components of a drivetrain. Examples of such other components include differentials, torque converters, front or rear axles, propeller shafts, and flywheels.
The first and second input shafts 104 and 114 may be coaxial or eccentric. The first input shaft 104 may partially enclose the second input shaft 114. Alternatively, the second input shaft 114 may partially enclose the first input shaft 104. Figure 1 shows the first and second input shafts 104 and 114 in a coaxial arrangement with the first input shaft 104 partially enclosing the second input shaft 114. The coaxial and enclosing arrangement shown is an advantageously compact arrangement.
Transmission 100 also comprises a coupling mechanism 122. Coupling mechanism 122 is configured to controllably engage. Engaging the coupling mechanism 122 (i.e. closing the coupling) causes the first and second input shafts 104 and 114 to become positively connected. The coupling mechanism 122 may comprise a dog/j aw/tooth/positive-contact clutch. The coupling mechanism 122 may comprise a reduction gear. The reduction gear may be an epicyclic/planetary gear. Hence, positive connection should not be understood to imply that a 1 : 1 gear ratio is required.
The first input shaft 104 carries one or more wheels 106, 108, 110. The second input shaft 114 carries one or more wheels 116, 118, 120. Each wheel on one shaft may be configured to engage a corresponding wheel on the output shaft 124 so as to drive it to rotate or be driven by it to rotate. The engagement may be positive contact (as in the engagement between two gear wheels) or frictional (as in the engagement of two smooth-surfaced wheels). Examples of such positive contact wheels include gears such as spur gears, helical gears, bevel gears, miter gears, screw gears, worm gears. Examples of friction wheels include pulley wheels, and elastomeric or rubber wheels. The term‘wheel’ should not be understood to denote size/diameter. The wheels may alternatively be referred to as pinions.
In the example shown in Figure 1 , the output shaft 124 carries wheels 126, 128, 130, 132, 134 and 136. Wheels 126, 128, 130, 132, 134 and 136 can be rotationally fixed to or rotationally freed from the output shaft by a locking device. Each wheel on the output shaft 124 may be configured to engage a corresponding wheel on the first and second input shafts 104, 114 so as to drive or be driven by it. As will be described in detail below, a wheel on each of the first and second input shafts 104, 114 may simultaneously engage with corresponding wheels on the output shaft 124 so as to drive the output shaft 124. Transmission 100 is shown with three locking devices 138, 140 and 142. Each locking device is actuatable to rotationally fix or free at least one respective wheel 126, 128, 130, 132, 134 and 136 to or from the output shaft 124. Each locking device may be actuatable to rotationally fix or free two wheels to or from the output shaft, as in the example shown in Figure 1. The locking device may comprise a collar that wholly or partly excircles the output shaft 124.
One of wheels 126 and 136 can be rotationally fixed to or rotationally freed from the output shaft 124 by actuating a locking device 138. One of wheels 132 and 134 can be rotationally fixed to or rotationally freed from the output shaft 124 by actuating a locking device 140. One of wheels 128 and 130 can be rotationally fixed to or rotationally freed from the output shaft 124 by actuating a locking device 142.
Locking devices 138, 140 and 142 may each comprise a synchroniser. When locking devices 138, 140 and 142 comprise a synchroniser, the locking devices 138, 140 and 142 and associated wheels 126, 128, 130, 132, 134 and 136 may form a synchromesh arrangement. The neutral (i.e. not actuated/activated) position of each of the locking devices 138, 140, 142 is such that none of wheels 126, 128, 130, 132,
134 and 136 are coupled to the output shaft.
The labels of 1 to 6 above the wheels 126 to 136 in Figures 1 to 7 indicate the gears in which the transmission may operate. First gear will generally have the lowest gear ratio, followed by second, then third etc. Transmission 100 has at least 2 gear ratios (or driving gears). Transmission 100 may have three, four, five, six, seven, eight, or more gear ratios. Each wheel carried by the first and second input shafts 104, 114 may drive the output shaft in a different gear ratio. Each gear ratio is dictated by the relative size of a wheel carried by the output shaft 124 and a corresponding wheel carried by the first or second input shaft 104, 114.
In the example shown in Figure 1 , the first motor 102 is an electric motor and the second motor 112 is an internal combustion engine (ICE). The first and second motors 102 and 112 may each be an electric motor.
The operation of transmission 100 will now be described with reference to Figures 2 to 9. Figure 2 shows a mode of operation wherein the power from one motor is fed to the other motor. The flow of power through the transmission 100 is shown by the dotted arrows. In the example shown, the coupling mechanism 122 is engaged and none of the locking devices 138, 140 and 142 are actuated. The first motor 102 drives the first input shaft 104 which in turn drives the second input shaft 114 via the coupling mechanism 122. The second input shaft 114 then drives the second motor 112. In this mode of operation, an electric motor may act as a starter motor for an internal combustion engine. This mode of operation may be referred to as the engine start mode.
Additional or alternatively, the second motor 112 may provide power to the first motor 102 (i.e. the direction of the dotted arrows may be reversed). Operating in this mode, an internal combustion engine can drive an electric motor such that the electric motor acts as a generator. The power of the internal combustion engine may thereby be used to charge batteries. This mode of operation may be referred to as the electric generation mode.
The first and second motor 102 and 112 may operate independently. The
independence of the motors allows the transmission 100 to operate in an electric driving mode or internal combustion driving mode. The six-gear example shown in Figures 1 to 7, is capable of being driven in a three-gear mode powered solely by the first motor 102 or in a three-gear mode powered solely by the second motor 112.
The transmission 100 is capable of being driven in all gears powered solely by the first or second motor 102, 112 when the coupling 122 is closed and the other of the first or second motor 102, 112 is allowed to rotate freely.
Figure 3 shows the transmission 100 being driven in a first gear. In first gear, the first motor 102 drives the first input shaft 104. Locking device 138 is actuated such that the output shaft 124 may be driven by the first input shaft via wheels 106 and 126. It is advantageous to use an electric motor to drive the output shaft in the first gear as electric motors can provide the initial power required without the need for a starting/pull-away clutch. In other words, the transmission may operate in an electric launching mode. Furthermore, using an electric motor in the first gear allows the internal combustion engine to be deactivated whilst a vehicle is stationary, saving fuel that would otherwise be used to keep the combustion engine in its idle state.
Figure 9A shows an exemplary plot of the rotational speed of each of the first and second motors 102 and 112 against the time/distance travelled for a vehicle containing transmission 100. References to speed shall herein refer to rotational speed, unless otherwise labelled as vehicle speed or linear speed. In this example, the first motor 102 is an electric motor and the second motor 112 is an internal combustion engine. Hence, the line corresponding to the first motor 102 passes through the origin as, in the first gear, when the speed of the first motor is zero, the vehicle speed will be zero. The line corresponding to the second motor 112 does not pass through the origin as the internal combustion second motor 112 will have a minimum speed, NICEidle, below which the second motor 112 would stall. The circled numbers 1 to 6 denote the conventional driving gear associated with each region of the plot. The gradients of the lines (which should correspond to the gear ratio) are not represented accurately for simplicity.
The first region (1 ), generally corresponds to the first gear discussed above in relation to Figure 3. The speed of the first motor 102 increases from zero linearly with vehicle speed. In this region the speed of the second motor 112 is represented with a dashed line. This is to indicate that the second motor need not contribute any power. However, if more power is required, for example, if a greater acceleration is required, the second motor 112 may contribute power.
If the second motor 112 is to contribute power via wheel 126, the second motor 112 matches the speed of the first motor 102. Various examples of when this may occur are illustrated by the dashed lines in Figure 9A. In the first example, the speed of the second motor 1 12 substantially matches that of the first motor 102 as soon as the first motor reaches NICEIDLE Coupling mechanism 122 may then be engaged at any point. Once coupling mechanism 122 is engaged, the second motor 112 may contribute power. The transmission 100 will be referred to as being in a combined drive mode when both the first and second motor 102 and 1 12 contribute power. In the second and third examples, the second motor 1 12 remains at NICEIDLE until it is required to contribute power. When the second motor 1 12 is required to contribute power, it increases its speed to match that of the first motor 102. Once the speeds of the motors 102 and 112 are substantially equal, the coupling mechanism 122 may be engaged. Once coupling mechanism 122 is engaged, the second motor 1 12 may contribute power in a combined drive mode.
Figure 9B illustrates the state of the coupling mechanism 122. The coupling mechanism 122 will generally be open in the first gear, as described above with reference to Figure 3. Flowever, the coupling mechanism 122 may engage/close to enter the combined drive mode as described above with reference to Figure 9A. The combined drive mode options in region (1 ) in Figure 9B are shown with dashed lines, corresponding to the dashed lines in Figure 9A. As the dashed lines show, the transmission 100 may enter a combined drive mode at any point in region 1 (i.e. in a first gear), provided the speed of the first motor 102 is above NICEIDLE
Figure 9C illustrates the state of locking devices 138, 140 and 142. As discussed above, each locking device 138, 140 and 142 may be in one of three positions.
Locking device 138 may fix wheel 126 to the output shaft 124 (labelled 1 ,
corresponding to first gear), wheel 136 to the output shaft 124 (labelled 6,
corresponding to sixth gear), or be in a neutral position (labelled N). The transitions between these positions are shown in the top line of Figure 9C.
Locking device 140 may fix wheel 132 to the output shaft 124 (labelled 2,
corresponding to second gear), wheel 134 to the output shaft 124 (labelled 4, corresponding to fourth gear), or be in a neutral position (labelled N). The transitions between these positions are shown in the middle line of Figure 9C.
Locking device 142 may fix wheel 128 to the output shaft 124 (labelled 3,
corresponding to third gear), wheel 130 to the output shaft 124 (labelled 5, corresponding to fifth gear), or be in a neutral position (labelled N). The transitions between these positions are shown in the bottom line of Figure 9C. Shifting up
Figure 8 shows an exemplary series of steps 200 for changing up a gear, i.e. from gear X to gear X+1. This process will now be described with reference to Figures 3 to 7 which show the configuration of the transmission 100 at various stages of the process of shifting from the first to a second gear. In particular, the transition from region (1 ) to region (2) will be described by way of example.
The transmission 100 may be in a combined drive mode. The first step 202, is therefore to determine whether the transmission 100 is or is not in a combined drive (CD) mode. If the transmission 100 is in a combined drive mode, the coupling mechanism 122 is disengaged/opened at step 204. If the transmission is not in a combined drive mode, step 204 can be skipped as the coupling mechanism 122 will already be disengaged. In the example of shifting from first to second gear, the transmission 100 will now be in the configuration shown in Figure 3.
In step 206, the input shaft which is not driving the output shaft in gear X reaches a speed suitable for driving the output shaft in the desired next gear, X+1. Figure 4 shows an exemplary configuration of the transmission 100 during step 206 of shifting from first to second gear. In this example, the second motor 112 reaches a speed suitable for driving the output shaft 124 in a second gear. The dashed line in Figure 9A shows the second motor 104 reaching a speed suitable for driving the output shaft 124 in a second gear. The second motor 104 reaching a speed suitable for diving the output shaft 124 in a second gear corresponds to where the dashed line transitions to a solid line on the right hand side of region (1 ). The suitable speed is that at which wheel 116 can drive wheel 132 at a speed that substantially matches that of the output shaft 124. The second motor 112 is not yet driving the output shaft 124 as locking device 140 is in the neutral position. Locking device 140 is shown in the neutral position in the middle line of Figure 9C in region (1 ).
In step 208 the input shaft which reached a suitable speed in the previous step is coupled to output shaft 124 by the actuation of the appropriate locking device.
Figure 5 shows an exemplary configuration of transmission 100 after step 208 has been performed during the shift from first gear to second gear. Locking device 140 has been actuated to fix wheel 132 to the output shaft 124. The output shaft 124 is thus coupled to both the first and second motors 102 and 112. The actuation of locking device 140 from a neutral position when shifting from first to second gear is shown by the transition of the middle line in Figure 9C from N to 2.
In step 210 the input shaft which has been driving the output shaft 124 in gear X is decoupled from the output shaft 124 by the appropriate locking device returning to a neutral position. At this point the transmission is in gear X+1 but further steps may be performed. Figure 6 shows an exemplary configuration of the transmission 100 after step 210 has been performed during the shift from first gear to second gear. Locking device 138 returns to its neutral position, decoupling the first input shaft 104 and wheels 106 and 126 from the output shaft 124. From this point, the transmission is operating fully in second gear. The return of locking device 138 to a neutral position is shown by the transition of the top line in Figure 9C from 1 to N.
In step 212 it is determined whether or not the transmission should enter a combined drive mode. If combined drive mode is not requested, then no further steps are taken and the transmission 100 is driven by one of the two motors. If combined drive mode is requested, then step 214 is performed. In step 214, the input shaft which is not driving the output shaft in gear X+1 is slowed to reach a speed suitable for driving the output shaft in gear X+1. The suitable speed is that which substantially matches that of the other input shaft. This slowing may be performed actively. Examples of such active slowing include applying a friction brake and applying electromagnetic braking. The slowing may be allowed to occur passively through resistive forces.
The coupling mechanism 122 is then engaged in step 216 so as to positively connect the first and second input shafts 104 and 114. Figure 7 shows an exemplary configuration of the transmission 100 after step 216. The transmission 100 may now operate in a combined drive mode. The engagement of the coupling mechanism 122 when entering a combined drive mode in second gear is shown in Figure 9B as entering a closed state towards the end of region (1 ). Shifting down
The process for shifting down a gear, i.e. from gear X to gear X-1 , is similar to the process 200 for shifting up a gear shown in Figure 8. Figures 3 to 7 also
demonstrate an exemplary series of steps for shifting from second to first gear. In particular, the transition from region (2) to region (1 ) will be described by way of example, with the transmission 100 progressing from the state shown in Figure 7 to that shown in Figure 3.
Initially, the transmission 100 may be in combined drive mode in second gear, as described above with reference to Figure 7. The transmission 100 may however be driven solely by the second motor 112.
The first step 202, is therefore to determine whether the transmission 100 is or is not in a combined drive (CD) mode. If the transmission 100 is in a combined drive mode, the coupling mechanism 122 is disengaged at step 204. If the transmission is not in a combined drive mode, step 204 can be skipped as the coupling mechanism 122 will already be disengaged. In the example of shifting from second to first gear, the transmission 100 will now be in the configuration shown in Figure 6.
In step 206, the input shaft which is not driving the output shaft in gear X reaches a speed suitable for driving the output shaft in the desired next gear, X-1. Figure 6 shows an exemplary configuration of the transmission 100 during step 206 of shifting from second to first gear. In this example, the first motor 102 reaches a speed suitable for driving the output shaft 124 in a first gear. The suitable speed is that at which wheel 106 can drive wheel 126 at a speed that substantially matches that of the output shaft 124. The first motor 102 is not yet driving the output shaft 124 as locking device 138 is in the neutral position. Locking device 138 is shown in the neutral position in the top line of Figure 9C in region (2).
In step 208 the input shaft which reached a suitable speed in the previous step is coupled to output shaft 124 by the actuation of the appropriate locking device.
Figure 5 shows an exemplary configuration of transmission 100 after step 208 has been performed during the shift from second gear to first gear. Locking device 138 has been actuated to fix wheel 126 to the output shaft 124. The output shaft 124 is thus coupled to both the first and second motors 102 and 112. The actuation of locking device 138 from a neutral position when shifting from second to first gear is shown by the transition of the top line in Figure 9C from N to 1.
In step 210 the input shaft which has been driving the output shaft 124 in gear X is decoupled from the output shaft 124 by the appropriate locking device returning to a neutral position. At this point the transmission is in gear X-1 but further steps may be performed. Figure 4 shows an exemplary configuration of the transmission 100 after step 210 has been performed during the shift from second gear to first gear. Locking device 140 returns to its neutral position, decoupling the second input shaft 114 and wheels 116 and 132 from the output shaft 124. From this point, the transmission is operating fully in first gear. The return of locking device 140 to a neutral position is shown by the transition of the middle line in Figure 9C from 2 to N.
In step 212 it is determined whether or not the transmission should enter a combined drive mode. If combined drive mode is not requested, then no further steps are taken and the transmission 100 is driven by one of the two motors. If combined drive mode is requested, then step 214 is performed. In step 214, the input shaft which is not driving the output shaft in gear X-1 is adjusted to reach a speed suitable for driving the output shaft in gear X-1. The suitable speed is that which substantially matches that of the other input shaft.
The coupling mechanism 122 is then engaged in step 216 so as to positively connect the first and second input shafts 104 and 114. The transmission 100 may now operate in a combined drive mode. The engagement of the coupling mechanism 122 when entering a combined drive mode in first gear is shown in Figure 9B as the dotted lines remaining in a closed state in region (1 ).
Advantages
The transmission 100 as described above may provide several advantages over existing systems. The two motors 102 and 112 enable the transmission 100 to operate using only one of the two motors, in an electric driving mode or an internal combustion driving mode. In the case where the gears alternate between the first and second input shafts 104 and 114, the transmission 100 may operate in an alternating motor mode. For example, in the six-gear exemplary transmission 100, the output shaft 124 may be driven solely by the first motor 102 in gears one, three and five, and may be driven solely by the second motor 112 in gears two, four and six.
As described above, the transmission 100 may also operate in a three-gear mode powered solely by the first motor 102 or in a three-gear mode powered solely by the second motor 112. These operational modes provide redundancy in the event that a motor and/or its associated gearing malfunctions. For example, if the second motor 112 malfunctions the transmission 100 may operate in a three-gear mode powered solely by the first motor 102. Though powering the output shaft 124 with a single motor provides less power than utilising the combined drive capability, the option to only use one motor provides great flexibility.
The use of an electric motor as the first motor 102 allows the transmission 100 to accelerate a vehicle from a stop and travel at low speeds solely under electric power. This can allow the second motor 112 to be turned off at low speeds, saving electrical charge or fuel.
Transmission 100 may also operate without a clutch when the first motor 102 comprises an electric motor. A clutch-free configuration requires fewer parts, thus reducing the weight and cost of the system. The savings in weight and cost are particularly pronounced over dual clutch systems. Furthermore, the lack of a clutch eliminates the fluid drag losses that would be caused by a wet clutch. The lack of a wet clutch also removes the necessity for an engine driven high-pressure oil pump, thus reducing parasitic torque loss.
Transmission 100 allows for gear shifting to occur without substantial loss of torque. Torque loss during a gear shift is reduced as a consequence of at least one motor is driving the output shaft 124 at all times. Maximum torque is provided when the transmission 100 operates in combined drive mode. Thus, when only one motor is driving the output shaft 124, maximum torque is not provided. An example of when maximum torque is not provided is between steps 204 and 216 when the coupling mechanism 122 is disengaged. Such a drop in torque may be noticeable to a driver and may affect the driving experience. Flence further improvements to the system can be made to improve the driving experience.
Torque compensation
In instances when either motor is not providing its maximum torque when a gear shift is initiated, a noticeable drop in torque during gear shifts can be removed using the following method. An exemplary plot of the torque provided by each motor is shown in Figure 10A. Figure 10A shows two exemplary gear shifts, the shift from third gear to fourth gear and the shift from fourth gear to fifth gear. The torque of the first motor 102 is shown with a solid line and the torque of the second motor 112 is shown with a dashed line. In between gear shifts the motors each operate at a torque Ti. Ti is lower than the maximum torque that each motor is able to provide. During shifting from third to fourth gear, the first motor 102 initially provides a higher level of torque T2 to compensate for the second motor 112 being disconnected from the output shaft 124 and providing zero torque at step 204 of the method described above. The disengaging of the coupling mechanism 122 in step 204 is shown as the transition from closed to open in Figure 10B. As the second input shaft 114 is coupled to the output shaft 124 in step 208 and the first input shaft 104 is decoupled from the output shaft in step 210, the second motor 112 provides the higher level of torque T2 to compensate for the first motor 102 providing zero torque. The engaging of the coupling mechanism 122 in step 210 is shown as the transition from open to closed in Figure 10B.
The torque compensation method shown in Figures 10A and 10B prevents a noticeable drop in torque when the motors are not providing their maximum torque when a gear shift is initiated. Examples of situations when the motors may not be providing their maximum torque when a gear shift is initiated include: when the driver is not fully depressing the accelerator pedal, and when the motors are limited so as not to provide their maximum torque between gear shifts (though this would negatively affect the overall driving performance). If the transmission 100 is used to power a first axle, one or more auxiliary motor(s) may power a second axle. Flerein, the first axle will be assumed to be a rear axle of a vehicle and the second axle will be assumed to be a front axle of a vehicle. It should be appreciated that the position of the first and second axles could be varied or swapped. Further axles may be present without affecting the described methods of operation. Figures 1 1 A and 1 1 B show the torque profile of the vehicle, TTOTAL. TTOTAL is the combination of the torque provided at the rear axle (from transmission 1 00), TREAR, and the torque provided at the front axle (from the one or more auxiliary motor(s)), TFRONT. TREAR is a combination of the torque provided by the first motor 102 and the second motor 112. The combined torque provided by the first and second motors 102, 112 are shown with the dotted and dashed lines in Figures 11A and 11 B. The dotted line represents the torque provided by the outgoing gear (i.e. the gear you are shifting from). The dashed line represents the torque provided by the ongoing gear (i.e. the gear you are shifting to).
Torque infill
Figure 11A shows the torque profile when the transmission 100 operates according to the torque compensation method described above with reference to Figures 10A and 10B. Thus, in Figure 11A it is apparent that TTOTAL can remain constant by making use of the torque compensation method. Flowever, as described above, the torque compensation method may only be used in situations where each motor is providing less than its maximum torque.
Figure 11 B shows a solution to the loss of rear-axle torque suffered when driving at higher total torque levels that takes advantage of the auxiliary motor(s) on the front axle. The auxiliary motor(s) may increase its torque output during a gear shift. This is shown by the spike in TFRONT. This method may be used even when the rear motors are providing their maximum torque. Thus, the drop in torque from the rear motors during a gear shift can be compensated for by an increase in torque on the front axle. The auxiliary motor(s) may be configured to provide additional torque at a predetermined time during a gear shift. Additionally or alternatively, the auxiliary motor(s) may be configured to provide additional torque when the torque provided by one or both of the first and second motors to output shaft falls below a predetermined level.
KO clutch
The transmission may further comprise a clutch for disconnecting the second motor. Figure 12 shows an exemplary transmission 300 of the kind described above, further comprising a clutch 344 for disconnecting the second motor 312 from the second input shaft 314. Clutch 344 may be referred to as a KO clutch. KO clutch 344 is closed in its default state. When KO clutch 344 is opened, the second motor 312 is disconnected from the second input shaft 314, and thus from remainder of the transmission 300. When K0 clutch 344 is closed, the second motor 312 may drive the entirety of the second input shaft 314. K0 clutch 344 may be a wet clutch or a dry clutch. K0 clutch 344 may be a low inertia dry clutch in order to reduce weight, inertia, resistive losses and parasitic torque loss.
The K0 clutch may operate differently depending on whether the transmission 300 is shifting from an even numbered gear to an odd numbered gear, or vice versa.
Figure 13 shows an exemplary series of steps 400 for the operation of the K0 clutch 344 when shifting from an even numbered gear to an odd numbered gear. These steps may replace steps 210 to 216 shown in Figure 8 during a gear shift. For example, steps 400 may replace steps 210 to 216 when shifting from second to third gear or fourth to fifth gear. After step 208, the K0 clutch 344 is opened at step 402. In step 403 the second input shaft 314 is decoupled from the output shaft 324 by the appropriate locking device 338 or 340 returning to a neutral position.
In step 404 it is determined whether or not the transmission should enter a combined drive mode. If combined drive mode is not requested, then the K0 clutch is closed at step 408 and the transmission 300 is driven solely by the first motor 302.
If combined drive mode is requested, then the coupling mechanism 322 is then engaged in step 406 so as to positively connect the first and second input shafts 304 and 314. the KO clutch is closed at step 410 and the transmission 300 is driven by the first and second motors 302 and 312.
Figure 14 shows an exemplary series of steps 500 for the operation of the K0 clutch 344 when shifting from an odd numbered gear to an even numbered gear. These steps may replace steps 202 to 208 shown in Figure 8 during a shift from, for example, first to second gear, third to fourth gear, or fifth to sixth gear. At step 501 , the K0 clutch 344 is opened.
At step 502 it is determined whether the transmission 300 is or is not in a combined drive mode. If the transmission 300 is in a combined drive mode, the coupling mechanism 322 is disengaged/opened at step 504. If the transmission is not in a combined drive mode, step 504 can be skipped as the coupling mechanism 322 will already be disengaged.
In step 506 the second input shaft 314 is coupled to output shaft 324 by the actuation of the appropriate locking device 338 or 340.
The K0 clutch is then closed in step 507 and the remaining method steps 210 and 212 (and possibly 214 and 216 depending on the decision at step 212) can be completed as described in relation to Figure 8.
When the second motor 312 is an internal combustion engine, the moment of inertia of the engine is relatively high. Opening the K0 clutch 344 decreases the moment of inertial associated with the second input shaft 314. Opening the K0 clutch 344 also removes any binding torque generated by the second motor 312. This reduction in inertia and binding torque allows coupling mechanism 322 and locking mechanisms 338 and 340 to be engaged and disengaged more easily/readily.
Operating according to methods 400 or 500, the K0 clutch 344 can improve the speed gradient of the second motor 312. The speed gradient is the rate at which the motor can slow down, i.e. the gradient of the downslope between gears in Figure 9A. Disconnecting the engine allows the second input shaft 314 to slow down quicker due to the relatively low moment of inertia of the second input shaft 314. This allows the coupling mechanism 322, as well as locking mechanisms 338 and 340 to engage sooner and thus the gear shift to complete sooner. The reduced inertia also makes engaging the locking mechanisms 338, 340 easier.
The second input shaft 314 need not be slowed down when operating according to methods 400 and 500. It should be noted that the input shaft slowing step 214 is omitted from method 400. Similarly, the input shaft slowing step 206 is omitted from method 500. The rotation of the second input shaft 314 may be sped up instead.
Thus, when K0 clutch 344 is closed in step 410 or 507, the second motor 312 may provide a burst of power to the transmission 300. This power may be used to give an additional launch by providing a brief period of increased acceleration. Additionally or alternatively some of this power may be absorbed by an electric first motor 302.
The K0 clutch 344 also provides further functionality beyond the improved gear shifting described above. By opening the K0 clutch 344, the transmission 300 is able to drive in each gear, powered by the first motor 302 alone.
Furthermore, the K0 clutch 344 may be used to assist in launch so as to facilitate a range of regimes in which the vehicle can set off from rest. The second motor 312 can assist in launch, to provide an additional or alternative power source to the transmission. This is in contrast to the electric launching mode described above that solely uses the first motor 102/312.
The K0 clutch 344 can also be used to disconnect the second motor 312 in the event that the second motor 312 fails. This provides an additional safety precaution and can prevent a malfunction in the second motor 312 from damaging the rest of transmission 300. Similarly, a malfunction in the rest of the transmission 300 can be prevented from damaging the second motor 312.

Claims

1. A transmission (100) comprising:
an output shaft (124);
a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft;
a first motor (102) configured to drive the first input shaft;
a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft;
a second motor (112) configured to drive the second input shaft;
a coupling mechanism (122) configured to controllably engage to positively connect the first and second input shafts.
2. The transmission of claim 1 , the transmission being capable of driving the output shaft in a first gear when the transmission is in a state in which the coupling mechanism is disengaged and the output shaft is driven by a first wheel carried by the first input shaft.
3. The transmission of any claim 1 or 2, the transmission being capable of driving the output shaft in a first shifting mode when the transmission is in a state in which the output shaft is driven by a first wheel (116) carried by the second input shaft and a first wheel (106) carried by the first input shaft.
4. The transmission of any preceding claim, the transmission being capable of driving the output shaft in a second gear when the transmission is in a state in which the coupling mechanism is engaged and the output shaft is driven by a first wheel carried by the second input shaft.
5. The transmission of any preceding claim, wherein the first motor is an electric motor and the second motor is an internal combustion engine.
6. The transmission of any claim 5, the transmission being capable of operating in an engine start mode with the internal combustion engine inactive when the transmission is in a state in which the coupling mechanism is engaged such that the first input shaft drives the second input shaft.
7. The transmission of claim 5 or 6, the transmission being capable of operating in an electric generation mode when the transmission is in a state in which the coupling mechanism is engaged such that the second input shaft drives the first input shaft.
8. The transmission of any preceding claim, the transmission being capable of coupling the input and output shafts in four gears, the first gear having the lowest gear ratio of the four gears.
9. The transmission of any preceding claim, wherein the first input shaft carries wheels for driving the output shaft in the first gear and a third gear and the second input shaft carries wheels for driving the output shaft in a second and fourth gear.
10. The transmission of any preceding claim, wherein the wheels carried by the first and second input shafts are gearwheels.
11. The transmission of any preceding claim, wherein the first and second input shafts are coaxial.
12. The transmission of any preceding claim, further comprising a clutch configured to controllably disconnect the second motor from the second input shaft.
13. The transmission of claim 12, the transmission being capable of operating in a single engine mode with the second motor inactive when the coupling mechanism is engaged such that the first input shaft drives the second input shaft.
14. The transmission of any preceding claim, wherein each of the first and second motors is configured to provide additional torque when the other of the first and second motors is not driving the output shaft.
15. A motor vehicle comprising the transmission of any preceding claim, further comprising one or more auxiliary motor(s) for providing torque to an auxiliary axle, the auxiliary motor(s) configured to provide additional torque: at a predetermined time during a gear shift; and/or if the torque provided by one or both of the first and second motors to the output shaft falls below a predetermined level.
16. A method of shifting from a first gear to a second gear in a transmission (100), the transmission comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft, a second motor (112) configured to drive the second input shaft, the method comprising:
driving the output shaft with a first wheel (106) carried by the first input shaft and a first wheel (116) carried by the second input shaft;
disconnecting the first wheel carried by the first input shaft from the output shaft; and
positively connecting the first input shaft and the second input shaft.
17. A method as claimed in claim 16, further comprising, prior to driving the output shaft with the first wheel (106) carried by the first input shaft and the first wheel (116) carried by the second input shaft:
driving the output shaft with just the first wheel carried by the first input shaft.
18. A method as claim in claim 16 or claim 17, further comprising, prior to positively connecting the first input shaft and the second input shaft:
decreasing the speed of revolution of the first input shaft to match the speed of revolution of the second input shaft.
19. A method of shifting from a second gear to a first gear in a transmission (100), the transmission comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft, a second motor (112) configured to drive the second input shaft, and wherein the first input shaft is initially positively connected to the second input shaft, the method comprising: driving the output shaft with a first wheel (116) carried by the second input shaft;
disconnecting the first input shaft and the second input shaft;
driving the output shaft with the first wheel carried by the second input shaft and a first wheel (106) carried by the first input shaft; and
disconnecting the first wheel carried by the second input shaft from the output shaft.
20. A method as claimed in claim 19, further comprising, prior to driving the output shaft with the first wheel (116) carried by the second input shaft and a first wheel (106) carried by the first input shaft:
increasing the speed of revolution of the first input shaft such that the first wheel carried by the first input shaft can drive the output shaft in a first gear.
21. A method of shifting from a second gear to a third gear in a transmission (100), the transmission comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft, a second motor (112) configured to drive the second input shaft, and wherein the first input shaft is initially positively connected to the second input shaft; the method comprising:
driving the output shaft with a first wheel (116) carried by the second input shaft;
disconnecting the first input shaft and the second input shaft;
driving the output shaft with the first wheel carried by the second input shaft and a second wheel (108) carried by the first input shaft;
disconnecting the first wheel carried by the second input shaft from the output shaft; and
positively connecting the first input shaft and the second input shaft.
22. A method as claimed in claim 21 , further comprising, prior to driving the output shaft with the first wheel carried by the second input shaft and a second wheel (108) carried by the first input shaft, decreasing the speed of revolution of the first input shaft to match the speed of revolution of the second input shaft.
23. A method as claimed in claim 21 or claim 22, further comprising, prior to positively connecting the first input shaft and the second input shaft:
decreasing the speed of revolution of the second input shaft to match the speed of revolution of the first input shaft.
24. A method as claimed in any of claims 21 to 23, wherein the transmission further comprises a clutch (344) configured to controllably disconnect the second motor from the second input shaft, the method further comprising, prior to disconnecting the first wheel carried by the second input shaft from the output shaft:
opening the clutch.
25. A method as claimed in claim 24, further comprising, subsequent to positively connecting the first input shaft and the second input shaft:
closing the clutch.
26. A method of shifting from a third gear to a second gear in a transmission (100), the transmission comprising an output shaft (124), a first input shaft (104) carrying one or more wheels (106, 108, 110) for driving the output shaft; a first motor (102) configured to drive the first input shaft, a second input shaft (114) carrying one or more wheels (116, 118, 120) for driving the output shaft, a second motor (112) configured to drive the second input shaft, and wherein the first input shaft is initially positively connected to the second input shaft; the method comprising:
driving the output shaft with a second wheel (108) carried by the first input shaft;
disconnecting the first input shaft and the second input shaft;
driving the output shaft with a first wheel (116) carried by the second input shaft and the second wheel (108) carried by the first input shaft;
disconnecting the first wheel carried by the second input shaft from the output shaft; and
positively connecting the first input shaft and the second input shaft.
27. A method as claimed in claim 26, further comprising, prior to driving the output shaft with a first wheel carried by the second input shaft and the second wheel carried by the first input shaft:
increasing the speed of revolution of the second input shaft such that the first wheel carried by the second input shaft can drive the output shaft in a first gear.
28. A method as claimed in claim 26 or claim 27, wherein the transmission further comprises a clutch (344) configured to controllably disconnect the second motor from the second input shaft, the method further comprising, prior to disconnecting the first input shaft and the second input shaft:
opening the clutch.
29. A method as claimed in claim 28, further comprising, subsequent to positively connecting the first input shaft and the second input shaft:
closing the clutch.
PCT/GB2020/050802 2019-03-25 2020-03-25 Seamless-shift transmission WO2020193976A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB1904112.8A GB201904112D0 (en) 2019-03-25 2019-03-25 Seamless-shift transmission
GB1904112.8 2019-03-25

Publications (1)

Publication Number Publication Date
WO2020193976A1 true WO2020193976A1 (en) 2020-10-01

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Application Number Title Priority Date Filing Date
PCT/GB2020/050802 WO2020193976A1 (en) 2019-03-25 2020-03-25 Seamless-shift transmission

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GB (1) GB201904112D0 (en)
WO (1) WO2020193976A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112706598A (en) * 2021-01-12 2021-04-27 中国重汽集团济南动力有限公司 Vehicle with double-motor drive axle
US11193558B2 (en) * 2019-05-02 2021-12-07 Loc Performance Products, Llc Transmission with dual bi-directional input and single bi-directional output
DE102023204338A1 (en) 2023-05-10 2024-04-11 Zf Friedrichshafen Ag Transmission for a drive train of a vehicle and method for controlling such a transmission

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US20050164827A1 (en) * 2004-01-23 2005-07-28 Beaty Kevin D. Hybrid powertrain system including smooth shifting automated transmission
EP1610038A1 (en) * 2004-06-21 2005-12-28 Getrag Ford Transmissions GmbH Double coupling transmission
EP3020588A2 (en) * 2014-11-14 2016-05-18 Saic Motor Corporation Limited Dual-motor power system for vehicle
CN108895128A (en) * 2018-06-30 2018-11-27 吉泰车辆技术（苏州）有限公司 Hybrid power transmission system with dual gear structure

Patent Citations (4)

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Publication number Priority date Publication date Assignee Title
US20050164827A1 (en) * 2004-01-23 2005-07-28 Beaty Kevin D. Hybrid powertrain system including smooth shifting automated transmission
EP1610038A1 (en) * 2004-06-21 2005-12-28 Getrag Ford Transmissions GmbH Double coupling transmission
EP3020588A2 (en) * 2014-11-14 2016-05-18 Saic Motor Corporation Limited Dual-motor power system for vehicle
CN108895128A (en) * 2018-06-30 2018-11-27 吉泰车辆技术（苏州）有限公司 Hybrid power transmission system with dual gear structure

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11193558B2 (en) * 2019-05-02 2021-12-07 Loc Performance Products, Llc Transmission with dual bi-directional input and single bi-directional output
CN112706598A (en) * 2021-01-12 2021-04-27 中国重汽集团济南动力有限公司 Vehicle with double-motor drive axle
DE102023204338A1 (en) 2023-05-10 2024-04-11 Zf Friedrichshafen Ag Transmission for a drive train of a vehicle and method for controlling such a transmission

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