US20200325969A9 - Continuously variable power split transmission - Google Patents
Continuously variable power split transmission Download PDFInfo
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- US20200325969A9 US20200325969A9 US16/355,911 US201916355911A US2020325969A9 US 20200325969 A9 US20200325969 A9 US 20200325969A9 US 201916355911 A US201916355911 A US 201916355911A US 2020325969 A9 US2020325969 A9 US 2020325969A9
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- gear
- sun gear
- entry unit
- planetary gears
- continuously variable
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- 230000005540 biological transmission Effects 0.000 title claims abstract description 38
- 230000008878 coupling Effects 0.000 claims abstract description 49
- 238000010168 coupling process Methods 0.000 claims abstract description 49
- 238000005859 coupling reaction Methods 0.000 claims abstract description 49
- 238000002485 combustion reaction Methods 0.000 claims abstract description 25
- 230000007704 transition Effects 0.000 claims description 19
- 230000003100 immobilizing effect Effects 0.000 claims description 4
- 230000004907 flux Effects 0.000 claims 2
- 230000002706 hydrostatic effect Effects 0.000 description 5
- 230000001360 synchronised effect Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 239000000969 carrier Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
- F16H37/02—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
- F16H37/06—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts
- F16H37/08—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing
- F16H37/0833—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths
- F16H37/084—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths at least one power path being a continuously variable transmission, i.e. CVT
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- 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
- F16H3/44—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion using gears having orbital motion
- F16H3/62—Gearings having three or more central gears
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- 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
- F16H3/44—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion using gears having orbital motion
- F16H3/76—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion using gears having orbital motion with an orbital gear having teeth formed or arranged for obtaining multiple gear ratios, e.g. nearly infinitely variable
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
- F16H37/02—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
- F16H37/06—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts
- F16H37/08—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing
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- 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
- F16H47/00—Combinations of mechanical gearing with fluid clutches or fluid gearing
- F16H47/02—Combinations of mechanical gearing with fluid clutches or fluid gearing the fluid gearing being of the volumetric type
- F16H47/04—Combinations of mechanical gearing with fluid clutches or fluid gearing the fluid gearing being of the volumetric type the mechanical gearing being of the type with members having orbital motion
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
- F16H37/02—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
- F16H37/06—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts
- F16H37/08—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing
- F16H37/0833—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths
- F16H37/084—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths at least one power path being a continuously variable transmission, i.e. CVT
- F16H2037/0866—Power split variators with distributing differentials, with the output of the CVT connected or connectable to the output shaft
- F16H2037/0873—Power split variators with distributing differentials, with the output of the CVT connected or connectable to the output shaft with switching, e.g. to change ranges
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
- F16H37/02—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
- F16H37/06—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts
- F16H37/08—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing
- F16H37/0833—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths
- F16H37/084—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths at least one power path being a continuously variable transmission, i.e. CVT
- F16H2037/088—Power split variators with summing differentials, with the input of the CVT connected or connectable to the input shaft
- F16H2037/0886—Power split variators with summing differentials, with the input of the CVT connected or connectable to the input shaft with switching means, e.g. to change ranges
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
- F16H37/02—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
- F16H37/06—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts
- F16H37/08—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing
- F16H37/0833—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths
- F16H37/084—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths at least one power path being a continuously variable transmission, i.e. CVT
- F16H2037/0893—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings with a plurality of driving or driven shafts; with arrangements for dividing torque between two or more intermediate shafts with differential gearing with arrangements for dividing torque between two or more intermediate shafts, i.e. with two or more internal power paths at least one power path being a continuously variable transmission, i.e. CVT characterised in the ratio of the continuously variable transmission is different from zero when the output shaft speed is zero
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- 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
- F16H2200/00—Transmissions for multiple ratios
- F16H2200/003—Transmissions for multiple ratios characterised by the number of forward speeds
- F16H2200/0043—Transmissions for multiple ratios characterised by the number of forward speeds the gear ratios comprising four forward speeds
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- 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
- F16H2200/00—Transmissions for multiple ratios
- F16H2200/20—Transmissions using gears with orbital motion
- F16H2200/2002—Transmissions using gears with orbital motion characterised by the number of sets of orbital gears
- F16H2200/2007—Transmissions using gears with orbital motion characterised by the number of sets of orbital gears with two sets of orbital gears
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- 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
- F16H2200/00—Transmissions for multiple ratios
- F16H2200/20—Transmissions using gears with orbital motion
- F16H2200/203—Transmissions using gears with orbital motion characterised by the engaging friction means not of the freewheel type, e.g. friction clutches or brakes
- F16H2200/2041—Transmissions using gears with orbital motion characterised by the engaging friction means not of the freewheel type, e.g. friction clutches or brakes with four engaging means
Definitions
- the invention relates to a continuously variable power split transmission for powering vehicles and/or work machines by a combustion engine, comprising a variator, a summing gear train and a number of couplings, the variator delivering a fraction of the power of the combustion engine with a speed that is continuously variably controlled between maximum speeds in both directions to the summing gear train, where it is superposed to the other fraction of the power, and where transition between a plurality of ranges occurs in points of synchronism, the summing gear train being a planetary gear train with four shafts comprising a sun wheel as first central wheel, a second central wheel, a ring gear and a number of planetary gears held on a planet carrier.
- the Patent publication DE 35 33 193 relates to such a power split transmission.
- the variator as well as the summing gear train are coaxial with the output shaft of the combustion engine.
- the variator being coaxial with the input, a hollow shaft is required.
- the summing gear train is of the planetary type with two ring gears and communicates with the couplings on the final output side via two further hollow shafts, one inside the other.
- the summing gear train and the hollow shafts are very expensive, particularly the wide outer one of the two nested hollow shafts.
- the disposition of the couplings on the exit side is very disadvantageous, as they must be dimensioned for the whole exit torque and therefore are very bulky.
- the transmission has only three ranges whereof one range is purely hydrostatic and two ranges are power-split.
- a further power split transmission is described in the publication U.S. Pat. No. 9,488,263. It comprises two planetary gear train modules, namely a differential module on the entry side and a range module on the exit side, and a variator. Some couplings are interposed between the modules and one is disposed behind the range module. In this transmission the couplings are very bulky, too, as they must be dimensioned for the sum of the mechanically transmitted and the superposed hydrostatic torques. The adduction of control fluid to the couplings is tricky because some couplings are located between the modules and a further coupling on the exit side. Altogether, a higher number of couplings in relation to the number of ranges is required.
- All the couplings and brakes incorporated in the entry unit are dimensioned for the entry torque (which is lower than the output torque), upstream of the final reduction and only for the mechanically transmitted fraction of the torque. Therefore the whole transmission is less bulky and the adduction of oil for operating the couplings is simpler.
- the summing gear train with four shafts comprises only one planetary gear train, unlike the state of the art.
- One geared element (the central gear, either a sun gear or a ring gear) is omitted. This results in a simpler, shorter and cheaper design of the whole transmission and permits the input shaft and the output shaft of the whole transmission to be coaxial. And yet only one hollow shaft is required.
- the mechanical power path leads, depending on the range, either through the first sun gear or the first ring gear.
- the path from the variator leads in every range over a second central gear which is either the second sun gear or the second ring gear. This results in more flexibility design wise.
- the exit drive is via the planet carrier.
- the second central gear is a sun gear and the power output is either by way of a hollow shaft or by way of a planet carrier provided with an exit shaft or an exit gear.
- the second central gear is a ring gear and the exit drive is via a plain (not hollow) shaft. This latter embodiment is particularly suitable for straight-through drive. This means that the input shaft and the output shaft of the transmission are concentric.
- the variator can be hydrostatic or motor-electric or otherwise and located wherever suitable for the particular application, and drivingly connected with the second central gear which is either the sun gear or the ring gear of the summing gear train.
- first ring gear and the first sun gear of the summing gear train are located adjacent the entry unit and the planet carrier and the second central wheel are located at the opposite side, and sets of first planet gears and second planet gears meshing with each other are journaled on the planet carrier.
- This type of planet gear train is known as Ravigneaux—train.
- the second planet gears mesh with the second sun gear
- the second planet gears mesh with the second ring gear, all other features being identical.
- the entry unit communicating with the summing gear train only via adjacent elements (first sun gear and first ring gear) of the summing gear train, the entry unit can be varied without modifying the summing gear train.
- the input shaft from the combustion engine directly drives either the first sun gear via a first coupling or alternatively the first ring gear via a second coupling.
- a first brake is added for immobilizing the first ring gear.
- a break is also a coupling and therefore is encompassed by the term coupling in the claims.
- the entry unit comprises a basic planetary gear train acting as a step-up train that can be activated by a further brake on the input side of the entry unit.
- this step-up train comprises a planet carrier drivingly connected with the input shaft from the combustion engine and carrying the planet gears, and a sun gear on a drive-through shaft between the couplings and comprises a ring gear which can be immobilized by a second brake on the input side.
- the step-up gear train and the second brake are integrated together with the other couplings in the entry unit, thus reducing bulk and expense.
- FIG. 1 A first embodiment in longitudinal section, simplified,
- FIG. 2 A second embodiment in longitudinal section, simplified,
- FIG. 3 A rotating speed diagram for the first embodiment
- FIG. 4 A coupling table.
- FIGS. 1 and 2 the essential elements are referenced with suggestive acronyms, other elements with reference numbers. Casing, Variator and control are omitted for the sake of clarity.
- the acronyms stand for:
- the power path proceeds from left to right, from the combustion engine VM via entry shaft StW 0 to the entry unit E which contains all couplings and brakes and, in this case, an entry side planetary gear train PG 0 .
- the input shaft StW 0 forms at its end an entry unit planet carrier St 0 which also contains the outer half of the coupling arrangements C 0 and C 1 .
- the couplings here are clutches, even so they are operated in synchronous points, see below.
- the inner half of the coupling arrangement C 0 is coupled to the entry unit sun gear shaft SW 0 , which in the basic embodiment is also the first sun gear shaft SW 1 , terminating with the first sun gear S 1 of the summing gear train SG 1 .
- the input side sun gear shaft SW 0 is a through-drive shaft carrying the entry unit sun gear S 0 of the entry unit planetary gear train PG 0 .
- This planetary gear train PG 0 selectively operates as a step-up gear train.
- the entry unit sun gear S 0 meshes with the entry unit planetary gears P 0 journaled in the entry unit planet carrier St 0 .
- the entry unit planetary gears P 0 in turn mesh with the entry side ring gear H 0 .
- This ring gear H 0 can be locked with the casing (symbolized by hatched squares in FIG. 1 ) by means of the brake B 0 , thus immobilizing it.
- the inner half of coupling C 1 is located on the first ring gear shaft HW 1 and rigidly united with the first ring gear H 1 of the summing gear train SG 1 (SG 2 in FIG. 2 ).
- the mechanical fraction of the torque transmitted is provided to the summing gear train SG 1 either by way of the first ring gear shaft HW 1 or by way of the first sun gear shaft S 1 of the summing gear train SG 1 .
- the ring gear shaft HW 1 can be locked with the casing of the entry unit E by means of a brake B 1 .
- the summing gear train SG 1 acts as a high-ratio reduction gear train. In this range the first sun gear S 1 together with the sun gear shaft is idling.
- the summing gear train SG 1 is a planetary gear train with four shafts.
- the three entry shafts are the first sun gear shaft SW 1 and the first ring gear shaft HW 1 with ring gear H 1 for the mechanically transmitted fraction of the torque, and the central gear shaft SW 2 (In FIG. 1 the sun gear shaft with the sun gear S 2 ) for the fraction of the torque from the Variator V.
- the output shaft StW 1 here is a hollow shaft with the second sun gear shaft SW 2 inside.
- the arrangement of gears in the summing gear train SG 1 is as follows:
- the first sun gear S 1 meshes with the axially elongated first planetary gears P 1 which in turn mesh with the first ring gear H 1 and with the second planetary gears P 2 journaled on the same first planet carrier St 1 .
- Both sets of planetary gears P 1 , P 2 engaging each other is indicated in FIG. 1 by the lines 10 .
- the planet carrier St 1 can be featured as the output gear Z 1 , unless the output power is exported by way of the output shaft StW 1 . This depends on the position of the whole transmission in a particular application.
- the second embodiment depicted in FIG. 2 differs from FIG. 1 in that as a second central wheel, there is a second ring gear H 2 instead of the second sun gear S 2 of FIG. 1 .
- the second planetary gears P 2 are in meshing engagement with the first planetary gears P 1 (indicated by the lines 10 ) and with the second ring gear H 2 rigidly coupled with the second ring gear shaft HW 1 .
- the first planetary gears P 1 are—as in FIG.
- the second ring gear shaft HW 1 is a hollow shaft and the output shaft StW 1 is a plain shaft providing for easy drive-through through the entire transmission.
- the abscissa axis represents the speed of the vehicle (which is proportional with the rpm of the first planet carrier St 1 ), and the vertical ordinate axis represents the rotating speed of various elements depending on the speed of the vehicle.
- the forward ranges are referred to with F 1 through F 4 , the slow reverse range with FR.
- the points of transition are referred to as 0 (travelling speed zero, transition from forward to reverse), as 1 (transition from F 1 to F 2 ), as 2 (transition from F 2 to F 3 ) and with 3 (transition from F 3 to F 4 ).
- Variator V drives the planet carrier St 1 and therewith the output StW 1 by way of the second gear shaft SW 2 , the second sun gear S 2 , and the first and second planetary gears P 2 , P 1 .
- the first sun gear S 1 is idling (couplings C 1 and C 2 being disengaged) at the same rpm as the second sun gear S 2 , but in opposite sense.
- the vehicle is driven by the variator V alone. Reversing is achieved simply by reversing the sense of rotation of the variator.
- the second range F 2 is engaged in the point of transition 1, the variator V and the sun gear S 1 having reached the maximum rotating speed in range F 1 , by closing coupling C 1 and opening the brake B 1 .
- the rotating speed of the combustion engine VM is constant and equals the speed n_S 1 of the first sun gear S 1 .
- This point of transition 2 is a further point of synchronism, wherein the rotating speeds n_S 1 and n_H 1 are equal.
- the speed of the first sun gear S 1 (and therewith the speed of the combustion engine VM) is constant.
- the third range F 3 is engaged in point 3 by opening coupling C 0 and simultaneously closing coupling C 1 , again both couplings do not slip in this point of synchronism.
- the fraction of the torque of the combustion engine VM moves from the first sun gear S 1 to the first ring gear H 1 , which now rotates with a speed of n_H 1 .
- the speed n_S 2 of the variator V and therewith of the second sun gear S 2 starts to drop until it reaches its maximum in the opposite sense of rotation.
- the first sun gear S 1 idles with a speed of n_S 1 .
- the fourth range F 4 is engaged in the synchronous transition point 3 by opening coupling C 1 and closing the brake B 0 .
- the speed of the variator V and therewith the speed n_S 2 of the sun gear S 2 now starts dropping again.
- the entry side planetary gear train PG 0 now acts as a step-up gear train. Its step-up ratio is chosen so that the first sun gear S 1 idling with the speed n_S 1 in the third range has reached the speed corresponding to the speed of the combustion engine VM in the point of transition 4.
- coupling C 1 and brake B 0 are switched without slip.
- the speed of the variator is again varied from a maximum in one sense of rotation to the maximum in the opposite sense.
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Abstract
Description
- The invention relates to a continuously variable power split transmission for powering vehicles and/or work machines by a combustion engine, comprising a variator, a summing gear train and a number of couplings, the variator delivering a fraction of the power of the combustion engine with a speed that is continuously variably controlled between maximum speeds in both directions to the summing gear train, where it is superposed to the other fraction of the power, and where transition between a plurality of ranges occurs in points of synchronism, the summing gear train being a planetary gear train with four shafts comprising a sun wheel as first central wheel, a second central wheel, a ring gear and a number of planetary gears held on a planet carrier.
- The Patent publication DE 35 33 193 relates to such a power split transmission. The variator as well as the summing gear train are coaxial with the output shaft of the combustion engine. The variator being coaxial with the input, a hollow shaft is required. The summing gear train is of the planetary type with two ring gears and communicates with the couplings on the final output side via two further hollow shafts, one inside the other. The summing gear train and the hollow shafts are very expensive, particularly the wide outer one of the two nested hollow shafts. The disposition of the couplings on the exit side is very disadvantageous, as they must be dimensioned for the whole exit torque and therefore are very bulky. The transmission has only three ranges whereof one range is purely hydrostatic and two ranges are power-split.
- A further power split transmission is described in the publication U.S. Pat. No. 9,488,263. It comprises two planetary gear train modules, namely a differential module on the entry side and a range module on the exit side, and a variator. Some couplings are interposed between the modules and one is disposed behind the range module. In this transmission the couplings are very bulky, too, as they must be dimensioned for the sum of the mechanically transmitted and the superposed hydrostatic torques. The adduction of control fluid to the couplings is tricky because some couplings are located between the modules and a further coupling on the exit side. Altogether, a higher number of couplings in relation to the number of ranges is required.
- At last, a power split transmission with a hydrostatic or electric variator is described in the publication EP 2258966 B. Its summing gear train comprises two complete planetary gear trains (sun wheel, ring gear and planets on a planet carrier), whose sun wheels are located on a common shaft, thus rigidly coupled to each other. Likewise rigidly coupled are the planet carriers of both planetary gear trains. The mechanical power path comprises a number of sets of spur gears. Therefore an embodiment with coaxial entry and exit shafts is impossible and the whole transmission is very large. A further disadvantage is that the transition to the highest range does not occur in a point of synchronism.
- The problem the invention sets out to solve, is to create a transmission of this kind that avoids all the mentioned disadvantages. It must be simpler in design with less and cheaper components and less bulky, and yet it must have a higher functionality. This is achieved by the characteristic features of the independent claims and also as disclosed herein.
- All the couplings and brakes incorporated in the entry unit are dimensioned for the entry torque (which is lower than the output torque), upstream of the final reduction and only for the mechanically transmitted fraction of the torque. Therefore the whole transmission is less bulky and the adduction of oil for operating the couplings is simpler.
- The summing gear train with four shafts comprises only one planetary gear train, unlike the state of the art. One geared element (the central gear, either a sun gear or a ring gear) is omitted. This results in a simpler, shorter and cheaper design of the whole transmission and permits the input shaft and the output shaft of the whole transmission to be coaxial. And yet only one hollow shaft is required.
- The mechanical power path leads, depending on the range, either through the first sun gear or the first ring gear. The path from the variator leads in every range over a second central gear which is either the second sun gear or the second ring gear. This results in more flexibility design wise. The exit drive is via the planet carrier.
- The flexibility is the result of the two possible embodiments of the summing gear train, without any modification to the entry unit. In the first embodiment the second central gear is a sun gear and the power output is either by way of a hollow shaft or by way of a planet carrier provided with an exit shaft or an exit gear. In the second embodiment the second central gear is a ring gear and the exit drive is via a plain (not hollow) shaft. This latter embodiment is particularly suitable for straight-through drive. This means that the input shaft and the output shaft of the transmission are concentric.
- The variator can be hydrostatic or motor-electric or otherwise and located wherever suitable for the particular application, and drivingly connected with the second central gear which is either the sun gear or the ring gear of the summing gear train.
- In an advantageous development, the first ring gear and the first sun gear of the summing gear train are located adjacent the entry unit and the planet carrier and the second central wheel are located at the opposite side, and sets of first planet gears and second planet gears meshing with each other are journaled on the planet carrier. This type of planet gear train is known as Ravigneaux—train. In the first embodiment, the second planet gears mesh with the second sun gear, in the second embodiment the second planet gears mesh with the second ring gear, all other features being identical.
- The entry unit communicating with the summing gear train only via adjacent elements (first sun gear and first ring gear) of the summing gear train, the entry unit can be varied without modifying the summing gear train. In a basic embodiment, the input shaft from the combustion engine directly drives either the first sun gear via a first coupling or alternatively the first ring gear via a second coupling.
- In a first development of the entry unit, a first brake is added for immobilizing the first ring gear. A break is also a coupling and therefore is encompassed by the term coupling in the claims. By actuating this brake and closing no other coupling, a slowest range is provided with torque transmission by the variator only. In this range, the summing gear train acts as a high-ratio reduction gear train.
- In a more elaborate development, the entry unit comprises a basic planetary gear train acting as a step-up train that can be activated by a further brake on the input side of the entry unit. By this, a further range is created. In a preferred embodiment, this step-up train comprises a planet carrier drivingly connected with the input shaft from the combustion engine and carrying the planet gears, and a sun gear on a drive-through shaft between the couplings and comprises a ring gear which can be immobilized by a second brake on the input side. In this manner the step-up gear train and the second brake are integrated together with the other couplings in the entry unit, thus reducing bulk and expense.
- The invention will now be described and commented along with the following drawings, representing:
-
FIG. 1 : A first embodiment in longitudinal section, simplified, -
FIG. 2 : A second embodiment in longitudinal section, simplified, -
FIG. 3 : A rotating speed diagram for the first embodiment, -
FIG. 4 : A coupling table. - In
FIGS. 1 and 2 the essential elements are referenced with suggestive acronyms, other elements with reference numbers. Casing, Variator and control are omitted for the sake of clarity. The acronyms stand for: - VM Combustion engine
- SG Continuously variable power split transmission
- E Entry unit
- SG1 Summing gear train in a first embodiment
- SG2 Summing gear train in a second embodiment
- V Variator
- PG0 Step-up planetary gear train, in entry unit E
- H0 Ring gear, in entry unit E
- H1 First ring gear
- H2 Second ring gear in second embodiment
- P0 Planetary gears in entry unit E
- P1 First planetary gears
- P2 Second planetary gears
- S0 Sun gear in entry unit E
- S1 First sun gear
- S2 Second sun gear
- St0 Planet carrier in entry unit E
- St1 First Planet carrier
- StW0 Input shaft from VM
- StW1 Output shaft
- SW0 Sun gear shaft in entry unit E, (drive-through shaft)
- SW1 First sun gear shaft
- SW2 Second sun gear shaft (central gear shaft in first embodiment)
- HW1 First ring gear shaft
- HW2 Second ring gear shaft (central gear shaft in second embodiment)
- Z1 Output gear
- B0 Brake in entry unit E
- B1 First brake
- C0 Coupling for connection with S1
- C1 Coupling for connection with H1
- In
FIG. 1 the power path proceeds from left to right, from the combustion engine VM via entry shaft StW0 to the entry unit E which contains all couplings and brakes and, in this case, an entry side planetary gear train PG0. The input shaft StW0 forms at its end an entry unit planet carrier St0 which also contains the outer half of the coupling arrangements C0 and C1. The couplings here are clutches, even so they are operated in synchronous points, see below. - The inner half of the coupling arrangement C0 is coupled to the entry unit sun gear shaft SW0, which in the basic embodiment is also the first sun gear shaft SW1, terminating with the first sun gear S1 of the summing gear train SG1. In the embodiment shown in
FIG. 1 , the input side sun gear shaft SW0 is a through-drive shaft carrying the entry unit sun gear S0 of the entry unit planetary gear train PG0. This planetary gear train PG0 selectively operates as a step-up gear train. The entry unit sun gear S0 meshes with the entry unit planetary gears P0 journaled in the entry unit planet carrier St0. The entry unit planetary gears P0 in turn mesh with the entry side ring gear H0. This ring gear H0 can be locked with the casing (symbolized by hatched squares inFIG. 1 ) by means of the brake B0, thus immobilizing it. - The inner half of coupling C1 is located on the first ring gear shaft HW1 and rigidly united with the first ring gear H1 of the summing gear train SG1 (SG2 in
FIG. 2 ). Depending on the selected range, the mechanical fraction of the torque transmitted is provided to the summing gear train SG1 either by way of the first ring gear shaft HW1 or by way of the first sun gear shaft S1 of the summing gear train SG1. In order to provide a purely hydrostatic or electric range, the ring gear shaft HW1 can be locked with the casing of the entry unit E by means of a brake B1. In this range, the summing gear train SG1 acts as a high-ratio reduction gear train. In this range the first sun gear S1 together with the sun gear shaft is idling. - The summing gear train SG1 is a planetary gear train with four shafts. The three entry shafts are the first sun gear shaft SW1 and the first ring gear shaft HW1 with ring gear H1 for the mechanically transmitted fraction of the torque, and the central gear shaft SW2 (In
FIG. 1 the sun gear shaft with the sun gear S2) for the fraction of the torque from the Variator V. The output shaft StW1 here is a hollow shaft with the second sun gear shaft SW2 inside. - The arrangement of gears in the summing gear train SG1 is as follows: The first sun gear S1 meshes with the axially elongated first planetary gears P1 which in turn mesh with the first ring gear H1 and with the second planetary gears P2 journaled on the same first planet carrier St1. Both sets of planetary gears P1, P2 engaging each other is indicated in
FIG. 1 by thelines 10. In this embodiment, the planet carrier St1 can be featured as the output gear Z1, unless the output power is exported by way of the output shaft StW1. This depends on the position of the whole transmission in a particular application. - The second embodiment depicted in
FIG. 2 differs fromFIG. 1 in that as a second central wheel, there is a second ring gear H2 instead of the second sun gear S2 ofFIG. 1 . In this way, the second planetary gears P2 are in meshing engagement with the first planetary gears P1 (indicated by the lines 10) and with the second ring gear H2 rigidly coupled with the second ring gear shaft HW1. Due to the driving connection between both ring gears H1, H2, the second planetary gears P2 are wider (=axially elongated) than the first planetary gears P1. The first planetary gears P1 are—as inFIG. 1 —in meshing engagement with the first sun gear S1 and the first ring gear H1. In this embodiment, the second ring gear shaft HW1 is a hollow shaft and the output shaft StW1 is a plain shaft providing for easy drive-through through the entire transmission. - The mode of operation of the transmission of
FIG. 1 will now be described in reference toFIG. 3 . In the rotating speed diagram, the abscissa axis represents the speed of the vehicle (which is proportional with the rpm of the first planet carrier St1), and the vertical ordinate axis represents the rotating speed of various elements depending on the speed of the vehicle. These are: - The speed of the second sun gear S2, driven by the variator with a speed n_S2 in dashed line (long dashes),
- The speed of the first sun gear S1 driven by the combustion engine VM with a speed n_S1 in dashed line (short dashes),
- The speed of the first ring gear H1 with a speed n_H1 in dotted line,
- The speed of the planet carrier St1 as exit speed n_St1 in through line.
- The forward ranges are referred to with F1 through F4, the slow reverse range with FR. The points of transition are referred to as 0 (travelling speed zero, transition from forward to reverse), as 1 (transition from F1 to F2), as 2 (transition from F2 to F3) and with 3 (transition from F3 to F4).
- In the reverse range FR and in the first forward range F1, according to the table in
FIG. 4 , the brake B1 is closed, the first ring gear H1 thus immobilized (n_H1=0). Variator V drives the planet carrier St1 and therewith the output StW1 by way of the second gear shaft SW2, the second sun gear S2, and the first and second planetary gears P2, P1. The first sun gear S1 is idling (couplings C1 and C2 being disengaged) at the same rpm as the second sun gear S2, but in opposite sense. In this slow range, the vehicle is driven by the variator V alone. Reversing is achieved simply by reversing the sense of rotation of the variator. - The second range F2 is engaged in the point of transition 1, the variator V and the sun gear S1 having reached the maximum rotating speed in range F1, by closing coupling C1 and opening the brake B1. The rotating speed of the combustion engine VM is constant and equals the speed n_S1 of the first sun gear S1. Thus, the transition proceeds synchronously without slip in coupling C0 and brake B1. The output speed n_S2 of variator V now is reduced, crosses the line n=0 and picks up again in the opposite sense of rotation until the next point of
transition 2 is reached. This point oftransition 2 is a further point of synchronism, wherein the rotating speeds n_S1 and n_H1 are equal. In this range, the speed of the first sun gear S1 (and therewith the speed of the combustion engine VM) is constant. - The third range F3 is engaged in point 3 by opening coupling C0 and simultaneously closing coupling C1, again both couplings do not slip in this point of synchronism. By this, the fraction of the torque of the combustion engine VM moves from the first sun gear S1 to the first ring gear H1, which now rotates with a speed of n_H1. At the same time the speed n_S2 of the variator V and therewith of the second sun gear S2 starts to drop until it reaches its maximum in the opposite sense of rotation. In this range, the first sun gear S1 idles with a speed of n_S1.
- The fourth range F4 is engaged in the synchronous transition point 3 by opening coupling C1 and closing the brake B0. The speed of the variator V and therewith the speed n_S2 of the sun gear S2 now starts dropping again. By actuating the brake B0, the entry side planetary gear train PG0 now acts as a step-up gear train. Its step-up ratio is chosen so that the first sun gear S1 idling with the speed n_S1 in the third range has reached the speed corresponding to the speed of the combustion engine VM in the point of transition 4. In this synchronous point of transition also, coupling C1 and brake B0 are switched without slip. In this fourth range, the speed of the variator is again varied from a maximum in one sense of rotation to the maximum in the opposite sense.
- In this way a continuously variable power split transmission with four forward ranges and one reverse range with a synchronous transition throughout is achieved with less expenditure and a better functionality.
Claims (15)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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EP18000267.7A EP3543560B1 (en) | 2018-03-19 | 2018-03-19 | Infinitely variable branched transmission |
EP18000267 | 2018-03-19 | ||
EP1800267.7 | 2018-03-19 | ||
EP18000267.7 | 2018-03-19 |
Publications (3)
Publication Number | Publication Date |
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US20190285154A1 US20190285154A1 (en) | 2019-09-19 |
US10794458B2 US10794458B2 (en) | 2020-10-06 |
US20200325969A9 true US20200325969A9 (en) | 2020-10-15 |
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US16/355,911 Active 2039-04-04 US10794458B2 (en) | 2018-03-19 | 2019-03-18 | Continuously variable power split transmission |
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US (1) | US10794458B2 (en) |
EP (1) | EP3543560B1 (en) |
JP (2) | JP2019215075A (en) |
CN (1) | CN110285199A (en) |
PL (1) | PL3543560T3 (en) |
RU (1) | RU2769436C2 (en) |
Family Cites Families (20)
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DE2757300C2 (en) * | 1977-12-22 | 1982-08-12 | Zahnradfabrik Friedrichshafen Ag, 7990 Friedrichshafen | Power-split hydrostatic-mechanical compound transmission |
DE2758659C3 (en) * | 1977-12-29 | 1982-03-18 | Zahnradfabrik Friedrichshafen Ag, 7990 Friedrichshafen | Hydrostatic-mechanical transmission with power split |
DE3125123C2 (en) * | 1981-06-26 | 1987-01-08 | Zahnradfabrik Friedrichshafen Ag, 7990 Friedrichshafen | Gearbox for a front-wheel drive vehicle |
DE3533193C2 (en) * | 1985-09-18 | 1994-03-24 | Michael Meyerle | Stepless hydrostatic-mechanical branching gear for motor vehicles |
DE3536335A1 (en) * | 1985-10-11 | 1987-04-16 | Michael Meyerle | CONTINUOUSLY HYDROMECHANICAL BRANCHING GEARBOX FOR MOTOR VEHICLES |
DE3709191A1 (en) * | 1986-04-10 | 1988-05-11 | Michael Meyerle | CONTINUOUSLY BRANCHING GEARBOX, IN PARTICULAR FOR MOTOR VEHICLES |
US4856371A (en) * | 1987-03-12 | 1989-08-15 | Tractiontec Corporation | Traction drive transmission system |
JP2671463B2 (en) * | 1988-12-07 | 1997-10-29 | トヨタ自動車株式会社 | Gearbox for automatic transmission |
US5931758A (en) * | 1998-04-08 | 1999-08-03 | General Dynamics Land Systems, Inc. | Simplified multi-range hydromechanical transmission for vehicles |
RU2192572C1 (en) * | 2001-08-17 | 2002-11-10 | Коротков Эдуард Константинович | Universal holonomic drive with stepless change of torque (versions) |
US7011600B2 (en) * | 2003-02-28 | 2006-03-14 | Fallbrook Technologies Inc. | Continuously variable transmission |
RU2292270C2 (en) * | 2004-01-28 | 2007-01-27 | Снимщиков Вячеслав Константинович | Active transmission; direct engagement mechaical; gearbox with planetary friction clutch and independent rear drive; transfer case with mechanism to distribute toque between axles (wheels) |
US8251848B2 (en) * | 2006-08-03 | 2012-08-28 | Toyota Jidosha Kabushiki Kaisha | Power split dual input shaft transmission for vehicle |
DE102008027074A1 (en) * | 2007-06-21 | 2008-12-24 | Luk Lamellen Und Kupplungsbau Beteiligungs Kg | Power-split, continuously variable vehicle transmission |
AT11366U1 (en) | 2009-06-04 | 2010-09-15 | Dieter Ing Stoeckl | OVERLAY TRANSMISSION |
US20150345629A1 (en) * | 2012-12-28 | 2015-12-03 | Guangquan LIU | Gear, cam stepless transmissions and vehicles thereof |
JP2013064511A (en) * | 2013-01-06 | 2013-04-11 | Hideki Matsumura | Gear type continuously variable speed change mechanism |
DE102014204009A1 (en) * | 2014-03-05 | 2015-09-10 | Schaeffler Technologies AG & Co. KG | Multi-speed planetary gear system as a component of the drive train of a motor vehicle |
US9488263B2 (en) | 2014-08-15 | 2016-11-08 | Caterpillar Inc. | Modular arrangement for hydromechanical transmission |
DE102016200644B4 (en) * | 2016-01-19 | 2017-10-19 | Bayerische Motoren Werke Aktiengesellschaft | Compact multi-step transmission |
-
2018
- 2018-03-19 PL PL18000267T patent/PL3543560T3/en unknown
- 2018-03-19 EP EP18000267.7A patent/EP3543560B1/en active Active
-
2019
- 2019-03-15 RU RU2019107513A patent/RU2769436C2/en active
- 2019-03-18 CN CN201910204278.3A patent/CN110285199A/en active Pending
- 2019-03-18 JP JP2019049352A patent/JP2019215075A/en active Pending
- 2019-03-18 US US16/355,911 patent/US10794458B2/en active Active
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2023
- 2023-12-22 JP JP2023217123A patent/JP2024038055A/en active Pending
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JP2024038055A (en) | 2024-03-19 |
EP3543560B1 (en) | 2020-11-25 |
US10794458B2 (en) | 2020-10-06 |
CN110285199A (en) | 2019-09-27 |
RU2769436C2 (en) | 2022-03-31 |
RU2019107513A3 (en) | 2022-02-28 |
PL3543560T3 (en) | 2021-06-14 |
US20190285154A1 (en) | 2019-09-19 |
JP2019215075A (en) | 2019-12-19 |
EP3543560A1 (en) | 2019-09-25 |
RU2019107513A (en) | 2020-09-15 |
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