FR2819570A1 - GEARBOX WITH ROBOTIZED CONTROL OF MOTOR VEHICLE AND METHOD FOR MANAGING AN ELECTRONIC CONTROL UNIT OF SUCH A GEARBOX - Google Patents

Abstract

The invention provides a gearbox (10) comprising, from upstream to downstream, a clutch (12) capable of being coupled to an engine (14) of the vehicle, a primary shaft (16), a secondary shaft (18 ) parallel, and a bridge (20) transmitting a driving power to the wheels of the vehicle, of the type which comprises at least two gears (24, 26), each associated with a transmission ratio of the vehicle and interposed between the primary shaft (16 ) and the secondary shaft (18), each of which comprises a fixed pinion (28, 32) carried by the primary shaft (16) and a idler pinion (30, 34) which is carried by the secondary shaft (18) and which is likely to be clutched there by a clutch means (36, 38) associated, characterized in that a freewheel device (52) is interposed between the secondary shaft (18) and the means (36) of the idler gear (30) associated with a determined transmission ratio.

Description

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"Motor vehicle robotic control gearbox and method for managing an electronic control unit for such a gearbox"
The invention relates to a motor vehicle gearbox.

 The invention relates more particularly to a motor vehicle gearbox, of the type which comprises, from upstream to downstream, at least one clutch which is capable of being coupled to a vehicle engine, a primary shaft, at least one shaft secondary parallel to the primary shaft, and a bridge which is intended to transmit a driving power to at least one wheel of the vehicle, of the type which comprises at least two gears, each associated with a transmission ratio of the vehicle, which are interposed between the primary shaft and the secondary shaft, and each of which comprises a fixed pinion carried by the primary shaft and a idler pinion which is carried by the secondary shaft and which is capable of being linked therein in rotation by a means of associated dog clutch.

 Many examples of this type of gearbox are known.

 In most of the current so-called "robotic" gearboxes, that is to say the gearboxes for which the movements of the idler gear clutch means and the clutch are obtained using controlled actuators, said dog clutch means and the clutch are actuated according to a conventional succession of operations.

 Thus, for example, to go from a first to a second transmission gear, the first gear being initially clutched, it is necessary successively to disengage the clutch, then to clutch the first gear, then to clutch the second gear, then to '' re-couple the clutch.

 This succession of operations ultimately leads to high gear change times.

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This configuration is particularly disadvantageous for changing from the first forward gear to the second forward gear, or for switching in the opposite direction from the second forward gear to the first forward gear, for which a reduced gear change time is required.

 To overcome these drawbacks, the invention proposes a gearbox allowing the passage from one report to another according to a reduced number of operations.

 To this end, the invention provides a gearbox of the type described above, characterized in that a freewheel device is interposed between the secondary shaft and the idler gear clutch means associated with a determined transmission ratio, to reduce switching times from one transmission report to another.

- l'unité électronique comporte des moyens de pilotage du couple fourni par le moteur du véhicule, - les engrenages sont associés au premier et deuxième rapports de marche avant. According to other characteristics of the invention: - the freewheel device is associated with the idler gear of the most reduced row transmission ratio, - the freewheel device is linked to the shaft which carries it when the means of dog clutch to which it is linked is subjected to a torque greater than that to which the secondary shaft is subjected and the wheel device is crazy otherwise, the gearbox is a so-called robotic control box, the clutch and the dog clutch means of each idler gear are driven by actuators controlled by an electronic unit of the vehicle,

the electronic unit comprises means for controlling the torque supplied by the vehicle engine, the gears are associated with the first and second forward gear ratios.

 The invention also provides a method for managing the electronic unit described above, characterized in that when the first forward gear is changed to the second forward gear, the means for clutching the first gear

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marche avant étant actionné, l'unité électronique commande successivement : . le désaccouplement de l'embrayage, puis . l'actionnement du moyen de crabotage du pignon fou du deuxième rapport de marche avant, puis 'l'accouplement de l'embrayage, et
Selon une autre caractéristique du procédé, lors du passage du deuxième rapport de marche avant au premier rapport de marche avant, le moyen de crabotage du premier rapport de marche avant étant toujours actionné, l'unité électronique commande seulement le décrabotage du pignon fou du deuxième rapport de marche avant puis régule le couple du moteur du véhicule de manière que le dispositif de roue libre associé au premier rapport de marche avant soit lié à l'arbre qui le porte.

with forward gear actuated, the electronic unit successively controls: uncoupling the clutch, then. the actuation of the idler gear clutch means of the second forward gear, then 'the clutch coupling, and
According to another characteristic of the method, during the passage from the second forward gear to the first forward gear, the means for clutching the first forward gear being always actuated, the electronic unit controls only the clutching of the idler gear of the second forward gear ratio then regulates the torque of the vehicle engine so that the freewheeling device associated with the first forward gear is linked to the shaft carrying it.

 Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: - Figures 1 to 4 are schematic views in axial section of a gearbox according to the invention representing the different stages of the transition from a first forward gear to a second forward gear; and - Figure 5 is a view of the gearbox of Figure 1 illustrating the transition from the second forward gear to the first forward gear.

 In the following description, identical reference numerals designate identical parts or having similar functions.

 There is shown in the figures the assembly of a gearbox 10 of a motor vehicle produced in accordance with the invention.

 In known manner, the gearbox 10 is intended to be coupled to an engine 14 of the vehicle.

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The gearbox 10 comprises, from upstream to downstream, at least one clutch 12 which is coupled to the engine 14, a primary shaft 16, at least one secondary shaft 18 which is parallel to the primary shaft 16, and a bridge 20 which is intended to transmit motive power to at least one wheel 22 of the vehicle.

 In particular, the secondary shaft 18 drives the bridge 20 by means of a gear 22, which is more particularly known by the name of "bridge descent".

 The gearbox 10 comprises at least two gears 24 and 26 which are each associated with a transmission ratio of the vehicle and which are interposed between the primary shaft 16 and the secondary shaft 18.

 The gear 24 comprises a fixed pinion 28 which is carried by the primary shaft 16 and a idler pinion 30 which is carried by the secondary shaft 18.

 Similarly, the gear 26 includes a fixed pinion 32 which is carried by the primary shaft 16 and a idler pinion 34 which is carried by the secondary shaft 18.

 Each idler gears 30, 34 is capable of being clutched onto the secondary shaft 18 by means of an associated clutch means.

 The gearbox may include, in addition to the idler gearing devices, synchronization devices (not shown in the figures) of dimensions adapted to the characteristics of the gearbox and to the required transit time performance, for example devices synchronization type single cone or multi-cone synchronizers.

 In particular, the idler gear 30 is capable of being clutched to the secondary shaft 18 by means of a dog clutch 36 and the idler gear 34 is capable of being clutched to the secondary shaft 18 by a means dog clutch 38.

 In known manner, and without limitation of the invention, the dog clutch means 36 and 38 each comprise

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un moyeu fixe associé 40, 42 qui reçoit en coulissement un baladeur axial 44, 46 associé dont un jeu de cannelures intérieures (non représenté) est susceptible de coopérer avec des cannelures extérieures 48,50 respectives des pignons fous 30 et 34.

an associated fixed hub 40, 42 which slidably receives an axial sliding gear 44, 46 associated with which a set of internal grooves (not shown) is capable of cooperating with respective external grooves 48.50 of the idler gears 30 and 34.

 According to the invention, a freewheel device 52 is interposed between the secondary shaft 18 and the clutch gear of a idler gear associated with a determined transmission ratio, in order to reduce the times of passage of a transmission ratio. to the other.

 In the figures, there is shown a gearbox 10 comprising only two gears 24 and 26 which are respectively associated with a first forward gear and a second forward gear, but this configuration is in no way limiting of the invention, and the gearbox could have a greater number of gears associated with a greater number of transmission ratios.

 In the preferred embodiment of the invention, the freewheel device 52 is associated with the idler gear 30 of the first forward gear, that is to say the most reduced row transmission ratio.

 In the figures, the freewheel device 52 has been shown as being interposed between the secondary shaft 18 and the hub 40 which carries the sliding gear clutch 40 of the idler gear 30 of the first forward gear, but this arrangement is not not limiting of the invention.

 Indeed, the freewheel device 52 could be interposed between the hub 40 and the sliding gear 44, or between the set of splines 48 of the idler gear 30 and its outer periphery or even between the idler gear 30 and the secondary shaft 18 with or without an appropriate control device (dog clutch or other), controlled by the robotization device and allowing the pinion to remain free in certain phases of gearbox operation.

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According to the invention, the freewheel device 52 is blocked, that is to say linked to the secondary shaft 18 which carries it, when the clutch means 36 to which it is linked is subjected to a torque greater than the one to which the secondary shaft 18 is subjected.

 In other words, and as will be seen later in more detail with reference to FIGS. 2 to 4, when the motor 14 drives the primary shaft and exerts a driving torque on said primary shaft 16, the latter transmits by the intermediate of the gear 24 a motor torque C to the freewheel device 52 which is then locked.

 Conversely, when, for example, the clutch 12 is disengaged, the wheel 22 drives the bridge 20 and transmits by means of the lowering of the bridge 22 a torque C ′ to the secondary shaft 18, and therefore, the freewheel device 52 is insane, that is to say it is not linked to the secondary shaft 18.

 Furthermore, the gearbox 10 is advantageously a so-called "robotized" gearbox, the clutch 12 and the clutch gear 36,38 of the idler gears 30,34 are driven by actuators (not shown) controlled by an electronic unit ( not shown) of the vehicle.

 The electronic unit also comprises means for controlling the torque C which is supplied by the engine 14 of the vehicle.

 In this configuration, the electronic control unit of the gearbox 10 and of the engine 14 is capable of operating according to a management method which makes it possible to optimize the time for switching from the first forward gear to the second forward gear and d '' optimize the transition time from the second forward gear to the first forward gear.

 This configuration is shown in Figures 1 to 5.

 From an initial neutral position (not shown) in which the clutch 12 is open and in which none of the clutch means 36, 38 is clutched to the corresponding idler gear 30, 34, the electronic unit is likely to command, as illustrated in Figure 1, the

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crabotage du pignon fou 30 associé au premier rapport de marche avant, en actionnant le moyen de crabotage 36, comme représenté par la flèche de la figure 1.

clutching of the idler gear 30 associated with the first forward gear, by actuating the clutch means 36, as shown by the arrow in FIG. 1.

 Then, as illustrated in FIG. 2, the electronic unit is capable of controlling the closing of the clutch 12 so that an engine torque supplied by the engine 14 is transmitted to the secondary shaft 18 via the gear 24 associated with the first forward gear.

 Then, as illustrated in FIG. 3, in order to change from the first forward gear to the second forward gear, the electronic unit controls the opening of the clutch 12 at the same time as it controls the clutching of the means 38 for clutching the idler gear 34 associated with the second forward gear.

 Consequently, the clutch 12 being open, the freewheel device 52 is no longer linked to the secondary shaft 18 and the torque C ′, which corresponds to the torque supplied by the wheel 22 to the secondary shaft 18 when the vehicle drives, travels from the secondary shaft 18 to the primary shaft 1. 6 via the gear 26.

 Then, as illustrated in FIG. 4, the electronic unit again controls the closing of the clutch 12 and the gearbox 10 then operates according to the second forward gear, the freewheel device 52 remaining idle since the secondary shaft 18 is subjected to a torque C greater than that to which the idler gear 30 is subjected which is driven by the fixed gear 28, the reduction ratio of the second forward gear, which is defined by the gear 26, being higher than the reduction ratio of the first forward ratio which is defined by the gear 24.

 As can be seen, the passage from the first forward gear to the second forward gear considerably reduces the total operating time of the actuators, since there is no need to declutch the clutch means 36

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associé au pignon fou 30 du premier rapport de marche avant pour engager le deuxième rapport de marche avant.

associated with the idler gear 30 of the first forward gear to engage the second forward gear.

 Furthermore, as illustrated in FIG. 5, the method is capable of managing the electronic unit for the passage in the opposite direction from the second forward gear to the first forward gear.

 In this configuration, the clutch 12 being always closed, and the clutch gear 36 of the idler gear 30 associated with the first forward gear being always clutched, the electronic unit controls the clutch clutch clutch 38 of the idler gear 34 associated to the second forward gear and simultaneously regulates the torque supplied by the motor 14 so that the clutch gear 52 is subjected to a torque C greater than the torque to which the secondary shaft 18 is subjected due to its drive by the wheel 22 .

 It is noted that this configuration is particularly advantageous since the method uses to its advantage the known property of conventional dog clutch means according to which it is possible to clutch the dog clutch means 38 without opening the clutch 12.

 In this configuration, the transition from the second forward gear to the first forward gear is all the more advantageous since it does not require control of the actuators of the clutch 12 and of the clutch gear 36 of the second gear. forward to re-engage the first forward gear.

 This configuration finds its interest in a case of circulation of the vehicle at reduced speed, for example, in a traffic jam, for which a rapid engagement of the first forward gear is required so that the vehicle benefits from rapid recoveries.

 It will be noted that the gearbox 10 and the method of managing the computer which have been described in the present description are not detrimental to the comfort of use of the

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véhicule car, même si celui-ci se trouve, par rapport à un véhicule conventionnel, dépourvu de frein moteur lorsque le premier moteur de marche avant est engagé, l'utilisation d'un tel frein moteur est généralement exceptionnelle.

vehicle because, even if it is, compared to a conventional vehicle, devoid of engine brake when the first forward engine is engaged, the use of such an engine brake is generally exceptional.

 The gearbox 10 thus allows an improvement in the comfort of using the vehicle in low-speed driving configurations according to the first forward gear by eliminating the jolts linked to the reversal of the torque when the user releases his pressure on the vehicle's accelerator pedal.

Claims (8)

CLAIMS 1. Gearbox (10) of a motor vehicle, of the type which comprises, from upstream to downstream, at least one clutch (12) which is capable of being coupled to an engine (14) of the vehicle, a primary shaft (16), at least one secondary shaft (18) parallel to the primary shaft (16), and a bridge (20) which is intended to transmit a driving power to at least one wheel of the vehicle, of the type which comprises at least two gears (24,26), each associated with a transmission ratio of the vehicle, which are interposed between the primary shaft (16) and the secondary shaft (18) and each of which comprises a fixed pinion (28,32) carried by the primary shaft (16) and a idler pinion (30,34) which is carried by the secondary shaft (18) and which is capable of being linked to it in rotation by an associated dog clutch means (36,38) , characterized in that a freewheel device (52) is interposed between the secondary shaft (18) and the means (36) for clutching the idler gear (30) associated with a determined transmission ratio, to reduce the transition times from one transmission ratio to another.  2. Gearbox (10) according to the preceding claim, characterized in that the freewheel device (52) is associated with the idler gear (30) of the most reduced row transmission ratio.  3. Gearbox (10) according to the preceding claim, characterized in that the freewheel device (52) is linked to the shaft (18) which carries it when the clutch means (36) to which it is linked is subjected to a torque greater than that to which the secondary shaft (18) is subjected and in that it is crazy otherwise.  4. Gearbox (10) according to any one of the preceding claims, characterized in that it is a box (10) with so-called robotic control, the clutch (12) and the means (36,38) of interconnection of each idler gear (30.34) are <Desc / Clms Page number 11>  moved by actuators controlled by an electronic unit of the vehicle.

 5. Gearbox (10) according to the preceding claim, characterized in that the electronic unit comprises means for controlling the torque (C) supplied by the engine (14) of the vehicle.  6. Gearbox (10) according to any one of the preceding claims, characterized in that the gears 24, 26) are associated with the first and second forward gear ratios.  7. A method of managing an electronic control unit according to claim 6 taken in combination with claims 4 and 5, characterized in that, when changing from the first forward gear to the second forward gear, the means ( 36) for interconnection of the first forward gear being actuated, the electronic unit successively controls: - the uncoupling of the clutch (12), then - the actuation of the interconnection means (38) of the idler gear (34) of the second forward gear, then - clutch coupling (12).  8. A method of managing an electronic control unit according to the preceding claim, characterized in that, when changing from the second forward gear to the first forward gear, the means (36) for interconnection of the first gear with the front always being actuated, the electronic unit controls only the declutching of the idler gear (34) of the second forward gear then regulates the torque (C) of the engine (14) of the vehicle so that the freewheel device (52) associated with the first forward gear is linked to the shaft (18) which carries it.