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
  • F16H3/02—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion
  • F16H3/20—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion exclusively or essentially using gears that can be moved out of gear
  • F16H3/38—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion exclusively or essentially using gears that can be moved out of gear with synchro-meshing
  • F16H3/385—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion without gears having orbital motion exclusively or essentially using gears that can be moved out of gear with synchro-meshing with braking means
• • 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
  • F16H3/12—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 with means for synchronisation not incorporated in the clutches
• • 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
  • F16H63/00—Control outputs from the control unit to change-speed- or reversing-gearings for conveying rotary motion or to other devices than the final output mechanism
  • F16H63/02—Final output mechanisms therefor; Actuating means for the final output mechanisms
  • F16H63/30—Constructional features of the final output mechanisms
  • F16H63/302—Final output mechanisms for reversing

Definitions

• the invention relates to a gearbox for a motor vehicle.
• the invention relates to a gearbox for a motor vehicle, of the type which comprises three primary, secondary, and intermediate parallel shafts, of the type in which the primary shaft is linked in rotation to a vehicle engine by means of a clutch and carries at least a first fixed reverse gear pinion with straight teeth, of the type in which the secondary shaft is linked via a transmission to at least one wheel of the vehicle and carries at least a second fixed pinion reverse gear with straight teeth, of the type in which one of the primary or secondary shafts carries at least a third idler forward gear, eng renant with a fourth fixed forward gear which is carried by the other of these two shafts , which is capable of being synchronized by an axial synchronizer and then linked, by a dog clutch, in rotation to the shaft which carries it to transmit the motive power of the motor to the wheel of the following vehicle at least one forward gear ratio, and of the type in which the intermediate shaft carries a fixed intermediate reverse gear pinion with straight
• gearboxes of this type are known.
• This arrangement is generally preferred to an eng renage involving toothed wheels with helical teeth, which are quieter in operation but very expensive in terms of manufacturing. Such a cost is not justified in the construction of a motor vehicle gearbox in which the reverse gear is used very little compared to the other forward gear ratios.
• the invention provides means for synchronizing the speed of the gears of the reverse gear using pre-existing synchronization means of the gearbox.
• the invention provides a gearbox of the type described above, characterized in that it includes controlled means making it possible to brake the primary shaft, by actuating the synchronizer of the third idler gear for forward movement, in order to synchronize to synchronize the speed of the fixed intermediate reverse gear with that of the first non-fixed reverse gear carried by the primary shaft and with that of the second fixed reverse gear carried by the secondary shaft, before causing mutual engagement of these gears for establishing the reverse gear.
• the controlled means comprise an electronic control module which is capable of controlling at least one actuator axially actuating at least the synchronizer of the third idler gear for forward travel and / or axially actuating the shaft intermediate bearing the fixed intermediate reverse gear,
• the electronic control module is capable of receiving a command to switch from reverse gear provided by the position of a vehicle speed change member and information representative of the speed of the primary shaft,
• the electronic module successively controls the actuation of the synchronizer of the third forward idler gear without clutching it to its shaft, then the release of the synchronizer of the third idler forward gear, then the actuation of the intermediate shaft carrying the fixed intermediate gear back,
• the electronic module directly controls the actuation of the intermediate shaft carrying the fixed intermediate reverse gear
• the third idler gear and the fourth non-fixed forward gear q uth define a high-range forward gear allowing the primary shaft to be braked quickly using the associated synchronizer, - the fixed intermediate reverse gear meshes in permanently with the first non-fixed reverse gear pig carried by the primary shaft, the axial displacement of the intermediate shaft carrying out only the interconnection of the fixed intermediate reverse gear which it carries with the second fixed reverse gear carried by the secondary tree,
• the axial displacement of the intermediate shaft achieves simultaneous clutching of the fixed non-intermediate reverse gear pig which it carries with the first fixed reverse gear pinion carried by the primary shaft and with the second non-fixed pig reverse gear carried by the secondary tree
• Fig ure 1 is a flow diagram of the operation of a gearbox controlled by an electronic control module according to the invention
• FIG. 2 is a schematic view in axial section of a gearbox according to the invention.
• FIG. 2 schematically shows a powertrain 10 of a motor vehicle comprising a gearbox 12 produced according to the invention.
• the powertrain 10 comprises a motor 14 which is coupled, via a clutch 16, to a primary shaft 1 8 of the gearbox 12.
• the primary shaft 1 8 is capable of transmitting, in particular by means of a gear 20 associated with a forward gear, a driving power to a secondary shaft 22 in order to drive in rotation a transmission 24 of the vehicle linked to wheels 26 of the vehicle.
• the motive power of the motor 14 is also capable of being transmitted from the primary shaft 1 8 to the parallel secondary shaft 22 via a gear 40 associated with a reverse gear.
• the engine renage 40 comprises for example, and without limitation of the invention, a first fixed gear 42 of reverse gear which is linked in rotation to the primary shaft, an intermediate gear 44 of reverse gear and a second fixed gear 46 reverse gear which is linked in rotation to the secondary shaft 22.
• the gear 20 comprises for example a idler gear 30 forwards carried by the secondary shaft 22 and a q uighth non-fixed pig 28 forwards which is linked in rotation to the primary shaft 1 8, the third non-crazy pig 30 forwards being capable of being clutched to the secondary shaft 22 by means of a dog clutch device 32 which comprises in particular a dog clutch (not shown) and a synchronizer 34.
• a dog clutch device 32 which comprises in particular a dog clutch (not shown) and a synchronizer 34.
• the synchronizer 34 is a synchronizer which is capable, when it is moved axially along the secondary shaft 22, of carrying out the rotation drive of the third idler gear 30 of forward travel at the same speed of l secondary shaft 22 before the dog clutch (not shown) rotates it with secondary shaft 22.
• the gearbox 1 0 is a so-called robotic control gearbox in which in particular the synchronizer 34 can be actuated axially by an actuator 36 controlled by an electronic module 38 for controlling the gearbox.
• the engagement of the reverse gear ratio associated with the gear 40 is capable of being achieved by the simultaneous clutching of the intermediate reverse gear pinion 44 with the first 42 and second 46 fixed reverse gear pinions.
• intermediate reverse gear 44 is linked in rotation to an intermediate reverse gear shaft 45, which is slidably mounted axially with respect to the casing 48 of the gearbox 1 0, parallel to the primary shafts 1 8 and secondary 22 and it is, like the first 42 and second 46 fixed reverse gears, a pinion with straight teeth.
• the intermediate reverse gear 44 is capable of being moved axially by an actuator 50 from the rest position illustrated in which it is not clutched neither with the first non-fixed pig 42 for reversing the primary shaft 18 nor with the second fixed pinion 46 for reversing the secondary shaft 22, towards a position for engaging reverse gear in which the intermediate reverse gear shaft 45 is moved axially, to the right by considering FIG. 2, by the actuator 50 so that the right teeth of the intermediate reverse gear 44 engage simultaneously with the straight teeth of the first fixed gear 42 of reverse gear and of the second fixed gear 46 of reverse gear, thus achieving the reversal of direction of rotation necessary for establishing the reverse gear ratio.
• the actuator 50 is controlled by the electronic control module 38.
• the actuators 36 and 50 are advantageously electromechanical or hydraulic cylinders with at least two extreme axial positions.
• the actuator 36 can in particular be an actuator with two extreme axial positions and an intermediate axial position making it possible to control a double dog clutch device 32 (not shown) allowing the dog clutching of two forward idler gears associated with two different forward gears .
• the intermediate pinion 44 for reversing may have a toothing of great long axial length enabling it to engage permanently with the first fixed pinion 42 for reversing so that when its intermediate shaft 45 is moved axially by the actuator 50, its toothing meshes with the toothing of the second pinion fixed reverse 46 while continuing to mesh with the first non-fixed reverse reverse pig 42.
• the gearbox 10 includes a sensor 52 which can provide the electronic control module 38 with information representative of the speed of the primary shaft 18.
• the gearbox 1 0 comprises controlled means making it possible to brake the primary shaft 18 by actuating the synchronizer 34 of the third forward non-idle pig in order to synchronize the speed of the non-intermediate reverse pig 44 with those of the first fixed pinion 42 of the primary shaft 18 and of the second fixed pinion 46 of the secondary shaft 22.
• the electronic control module 38 is capable of controlling the operation of the actuators 36 and 50 and of the clutch 16 according to a defined sequence allowing this synchronization to be obtained. .
• the electronic control module 38 is capable, when it receives information L representative of the selection of the reverse gear of the vehicle by a vehicle shift lever (not shown), of issue a reverse command command MAR which initiates the reverse gear engagement sequence.
• the control module then issues an order O 16 to open the clutch 16 which controls the disengagement of the clutch 16.
• the electronic control module compares information ⁇ P representative of the speed of the primary shaft 18 which is supplied by the speed sensor 52, and to compare this information ⁇ P to a value of predetermined threshold corresponding to a clutch speed ⁇ c which determines the ideal speed of rotation of the primary shaft 1 8 for clutching the reverse gear.
• the ideal speed ⁇ c for reversing the reverse gear is a low speed, for example between 0 and 50 rpm. If the speed ⁇ P of the primary shaft 18 is less than or equal to the ideal reverse clutch speed ⁇ c , the electronic control module 38 directly controls the reverse clutch engagement by issuing a CMAR order of actuation of the actuator 50 which has the effect of axially displacing the intermediate shaft 45 of reverse gear and directly effecting the simultaneous clutching of the fixed intermediate gear 44 with the first fixed gear 42 and the second fixed gear 46 of reverse gear.
• the electronic control module 38 issues an order E 34 for actuating the synchronizer 34 associated with the third idler gear 30 for forward travel, this which has the effect of slowing down the primary shaft 18 by means of the gear 20, given that the vehicle, necessarily q uas almost stationary when the reverse gear is engaged, requires via the synchronizer 34 a zero speed at the third fixed gear 30 forward.
• the forward synchronizer 34 behaves like a brake on the primary shaft 18.
• the electronic control module again compares the rotation speed ⁇ P of the primary shaft to the speed ⁇ c ideal for interconnection of the intermediate reverse gear 44, this speed then being chosen as being zero speed so as to achieve perfect and silent interconnection. If the speed ⁇ P of the primary shaft 1 8 is not zero, this may be the case in particular if the primary shaft was rotating before the start of the sequence at a high speed or if the vehicle was not rigorously stationary, the electronic control module 38 maintains the actuation E 34 of the synchronizer 34.
• the electronic control module 38 issues a command R 34 for releasing the synchronizer 34, which has the effect of releasing the synchronizer 34, and the electronic control module 38 then emits the CMAR command for interconnection of the fixed non-intermediate pig 44 with the first fixed pinion 42 for reverse gear and the second non-fixed pig 46 for reverse gear.
• the control module then issues an order F 16 to close the clutch 16 which controls the clutch of the clutch 16, and the vehicle can start in reverse.
• the gearbox 1 0 produced in accordance with the invention advantageously makes it possible to benefit from a compact device performing silent synchronization of the reverse gear.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Structure Of Transmissions (AREA)
• Control Of Transmission Device (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=8846065

Family Applications (1)

Country Status (2)

Cited By (1)

Family Cites Families (5)

• 2000
  • 2000-03-17 WO PCT/FR2000/000651 patent/WO2001069104A1/fr not_active Application Discontinuation
  • 2000-03-17 EP EP00910974A patent/EP1264122A1/de not_active Withdrawn

Non-Patent Citations (1)

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