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
  • 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
• • 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
  • F16H37/086—CVT using two coaxial friction members cooperating with at least one intermediate friction member
• • 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 transmissions with summing differentials, with the input of the CVT connected or connectable to the input shaft
  • F16H2037/0886—Power-split transmissions with summing differentials, with the input of the CVT connected or connectable to the input shaft with switching means, e.g. to change ranges

Definitions

• the present invention relates to continuously variable ratio transmission systems. It is known to provide a continuously variable ratio transmission system having coaxial system input and output shaft and a continuously variable ratio transmission unit (known as a variator) connected coaxially to the system input shaft and having a coaxial variator output shaft.
• a mixing epicyclic gear train receives drives from the system input and from the variator output.
• clutches or other braking elements By appropriate use of clutches or other braking elements, the system can operate in a high-gearing regime or low-gearing regime. Examples of such transmissions can be found in JP-A-6-174033 and JP-A-62-255655.
• a multi-regime, continuously variable ratio transmission system comprising: coaxial system input and output shafts; a continuously variable ratio transmission unit (variator) connected coaxially to the system input shaft and having a coaxial variator output shaft; and a mixing epicyclic gear train having an input sun gear drivably connected to the variator output shaft, a planet carrier drivably connected to the system input shaft and a first planet gear mounted on the planet carrier and drivingly engaged with the input sun gear; characterised in that the first planet gear drives a first intermediate output shaft which is arranged coaxially with the system input shaft and which is selectively connectable to the system output shaft via a first clutch in a high- regime operation of the transmission; and in that the first planet gear provides the input for a second epicyclic gear train having an output which is selectively connectable to the system output shaft via a braking element in a low-regime operation of the transmission.
• the mixing epicyclic gear train of the above arrangement does not require an annulus or ring gear. This significantly reduces the physical size required for the mixing epicyclic gear set and, as a consequence, allows much greater flexibility with the selection of the relative sizes of the planet gear and planet carrier.
• the arrangement allows the selection of gears which permit the mixing epicyclic gear train to run at slower speeds as compared with the prior art arrangements, thereby reducing wear, minimising losses and reducing the demand on other components such as bearings.
• the first intermediate output shaft is provided with a sun gear which is driven by the first planet carrier of the mixing epicyclic gear train.
• the sun gear on the output shaft is the same size as the input sun gear.
• the axle of the planet gear of the mixing epicyclic gear train preferably carries a second planet gear which rotates with the first planet gear and drives the first intermediate output shaft.
• the second planet gear is the same size as the first planet gear.
• the axle of the first planet gear of the mixing epicyclic gear train may carry a third planet gear which rotates with the first planet gear and provides the input for the second epicyclic gear train.
• the second epicyclic gear train preferably comprises a second input sun gear driven by the mixing epicyclic gear train, a planet gear driven by the second input sun gear and a planet carrier forming the output of the second epicyclic gear train.
• the system further comprises intermediate gearing further connecting the mixing epicyclic gear train and the second input sun gear.
• the second epicyclic gear train comprises a second sun gear engaged with the planet gear of the second epicyclic gear train.
• the system comprises means for selectively braking the second sun gear.
• This may conveniently comprise a clutch interposed between the second sun gear and the transmission system casing.
• the sun gear is held stationary with respect to the transmission casing and the braking element comprises clutch means for selectively connecting the output of the second epicyclic gear train to the system output shaft.
• FIG. 1 is a diagrammatic illustration of a first embodiment of continuously variable transmission in accordance with the present invention.
• Fig. 2 is a diagrammatic illustration of a second embodiment of continuously variable transmission in accordance with the present invention, as a modification of the embodiment of Fig. 1.
• a continuously variable ratio transmission system comprises a variator V of the known toroidal race rolling traction type having two toroidally-recessed discs 10 arranged one at each end of the unit and a pair of similar output discs 12, each facing a respective one of the input discs 10 and rotating with each other.
• Sets of rollers 14 are mounted between the opposing faces of the input and output discs 10, 12 to transmit drive from the input discs 10 to the output discs 12 with a ratio which is variable by tilting the rollers 14.
• the input discs 10 are connected to and driven by a system input shaft 16.
• the variator provides an output via a tubular variator output shaft 18 which is arranged coaxially with the input shaft 16.
• the end of the shaft 18 remote from the variator V drives the sun gear SI of a first, mixing epicyclic gear train El.
• the carrier Cl of the gear train El is connected to, and driven by, the input shaft 16 and is also connected to the inner of the two variator input discs 10.
• the carrier Cl carries input planet gears PI which engage with, and are driven by, the sun gear SI.
• the planet gears PI are each mounted on the carrier Cl by means of an associated shaft 20 which additionally carries first and second output planet gears PX1 and PY1.
• Output planet gear PX1 is identical to planet gear PI and transfers the summed output of the gear train El via an output sun gear S2 (of the same size as input sun gear SI) to an intermediate output shaft 22 arranged coaxially with the system input shaft 16.
• Drive from the intermediate output shaft can be selectively transmitted via a high-regime clutch H to a system output shaft
• Output planet gear PY1 is of smaller diameter than planet gears PI and PXl and meshes with a pinion 26 formed on one end of a tubular intermediate output shaft 28 arranged coaxially with the input shaft 16.
• the opposite end of the intermediate output shaft is also provided with a pinion 30 of smaller diameter than pinion 26.
• the pinion 30 meshes with larger diameter planet gears P2 of a second, simple reversing epicyclic gear set D2.
• the planet gears P2 are mounted on a carrier C2 which is connected to a second tubular intermediate output shaft 32 arranged coaxially with the system input shaft 16, and which in turn is connected to the system output shaft 24.
• the planet gears P2 of the second epicyclic gear set E2 are each located at one end of a respective shaft 34 mounted in the carrier C2.
• the opposite end of each shaft 34 carries a further, smaller planet gear PX2 which mesh with a sun gear 36 located at one end of a tubular transfer shaft 38 arranged coaxially with the system input shaft 16.
• the other end of the transfer shaft 38 is connected to one side of a braking element in the form of a low-regime clutch L, the other side of which is connected to the transmission casing 40.
• the transmission can operate in one of three regimes, namely high regime, low regime and synchronous mode.
• the high regime clutch H In high regime, in which the transmission operates at ratios from synchronous mode ratio to deep overdrive, the high regime clutch H is engaged and the low regime clutch L is disengaged.
• the high regime clutch H In low regime, in which the transmission operates from full reverse, through "geared neutral" to synchronous mode ratio, the high regime clutch H is disengaged and the low regime clutch L is engaged. Disengagement of the high regime clutch H isolates the system output shaft 24 from the output planet gear PXl of the mixing epicyclic gear set El. Furthermore, engagement of the low regime clutch L allows the output drive from the first mixing epicyclic gear set El to the second epicyclic gear set E2 to be transferred to the carrier C2 of the second epicyclic gear set E2 by providing a reaction force from the transmission casing 40. The drive is then transmitted to the second tubular intermediate output shaft 32 and thence to the system output shaft 24.
• Moving from high regime to low regime or vice versa can be achieved in so-called "synchronous mode" in which the transmission operates in a condition in which the intermediate output shaft 22 leading from the mixing epicyclic gear set El and the second tubular intermediate output shaft 32 leading from the second epicyclic gear set E2 rotate at (or very near) the same speed.
• the clutch of the new regime is engaged, whereby both clutches are simultaneously engaged for a short time and the clutch of the old regime is then disengaged.
• the only gears which are actively engaged in the mixing epicyclic gear set El are the planetary gears PI and PY1, thereby minimising the losses which occur in the mixing epicyclic gear train El, particularly in power recirculation mode.
• the present invention allows the use of a mixing epicyclic gear set El which does not have an annulus or ring gear. Not only does this reduce the weight of the transmission, but it also allows greater flexibility with the selection of the relative sizes of planetary gears PI, PXl and PY1. This in turn allows the speed of the components to be reduced and reduces the number of meshes to a minimum.
• Fig. 2 The embodiment of Fig. 2 is very similar to that of Fig. 1, the only significant difference being the location of the low-regime braking member.
• Features of the Fig. 2 embodiment which correspond to features of the Fig. 1 embodiment are indicated by the same reference numerals and only the differences in construction will be described.
• the planet gears P2 and PX2 are identical to those of the first embodiment but the sun gear 36' is fixedly connected to the transmission casing 40.
• Drive from the second tubular intermediate output shaft 32' is taken continuously from the carrier C2 and is selectively connected to the system output shaft 24 by means of a low-regime clutch L'.
• the Fig. 2 variation has the advantage that when the low-regime clutch L' is disengaged, the second epicyclic gear train E2' is completely disengaged from the system output shaft 24 (as opposed to the first embodiment where the intermediate output shaft 32 is always engaged to the system output shaft 24), whereby any problem arising from the second epicyclic gear set during high- regime operation is not transmitted to the system output shaft 24.
• the invention is not restricted to the details of the foregoing embodiments.
• variators of types other than that described can be used.
• the sizes of the gears may be varied to suit the particular circumstances.
• the sun gear SI of the epicyclic gear train is the same size as the output sun gear S2. However, instead of being the same sizes SI maybe larger than, or smaller than, S2 if appropriate.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Transmission Devices (AREA)
• Structure Of Transmissions (AREA)
• Vehicle Body Suspensions (AREA)
• Control Of Transmission Device (AREA)
• Transmissions By Endless Flexible Members (AREA)
• Eye Examination Apparatus (AREA)
• Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)

Priority Applications (10)

Applications Claiming Priority (4)

Publications (1)

Family

ID=29585712

Family Applications (1)

Country Status (14)

Cited By (17)

Families Citing this family (27)

Citations (1)

Family Cites Families (6)

• 2003
  • 2003-05-28 DE DE60309021T patent/DE60309021T2/de not_active Expired - Lifetime
  • 2003-05-28 CN CN038121638A patent/CN1656329B/zh not_active Expired - Fee Related
  • 2003-05-28 MX MXPA04011832A patent/MXPA04011832A/es active IP Right Grant
  • 2003-05-28 CA CA2487064A patent/CA2487064C/en not_active Expired - Fee Related
  • 2003-05-28 WO PCT/GB2003/002332 patent/WO2003100295A1/en not_active Ceased
  • 2003-05-28 KR KR10-2004-7019211A patent/KR20050014842A/ko not_active Ceased
  • 2003-05-28 BR BR0311346-9A patent/BR0311346A/pt not_active IP Right Cessation
  • 2003-05-28 EP EP03730341A patent/EP1507991B1/en not_active Expired - Lifetime
  • 2003-05-28 JP JP2004507716A patent/JP4330528B2/ja not_active Expired - Fee Related
  • 2003-05-28 RU RU2004138300/11A patent/RU2307272C2/ru not_active IP Right Cessation
  • 2003-05-28 AU AU2003241023A patent/AU2003241023A1/en not_active Abandoned
  • 2003-05-28 US US10/515,803 patent/US7407459B2/en not_active Expired - Fee Related
  • 2003-05-28 AT AT03730341T patent/ATE342456T1/de not_active IP Right Cessation
  • 2003-05-28 ES ES03730341T patent/ES2276068T3/es not_active Expired - Lifetime

Patent Citations (1)

Also Published As

Similar Documents

Legal Events