Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
  • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
  • F01L1/352—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear using bevel or epicyclic gear
• • 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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D3/00—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive
  • F16D3/02—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive adapted to specific functions
  • F16D3/10—Couplings with means for varying the angular relationship of two coaxial shafts during motion

Definitions

• THIS INVENTION relates to a variable drive assembly in which first and second rotatable members, such as shafts and/or components, are coupled together in order to transmit torque and/or rotary motion in an adjustable manner.
• a variable drive assembly in which a first rotatable member carries a first coupling eiement which is rotatable with the first member and engages a second coupling element rotatably mounted on a carrier which is rotatable with the second member, rotation of the second coupling element by the first coupling element is precluded so that rotation of the first coupling element causes rotation of the carrier and the second member rotatable therewith, and adjusting drive means are mounted on the carrier for rotating the second coupling element to vary the coupling between the first and second rotatable members.
• Figure 1 is a view from one side of a variable drive assembly embodying the invention
• Figure 2 is a partly sectioned view taken from the left in Figure I ;
• Figure 3 is ⁇ view of the assembly from the other side;
• Figure 4 is a partly cross-sectional plan view of the assembly.
• the shaft I carries at ⁇ its end nearest the shaft 2 a worm-wheel b which is fixed to, or part of, shaft I .
• the shaft 2 carries at its end nearest the shaft I a carrier-hub 8 which is fixed to, or part of, shaft 2.
• a carrier structure Is mounted on the carrier -hub 8 and comprises a back-plate 7 from which extend two parallel arms 5 and 6 which are integral with or fixed to the backplate 7 which itself is integral with, or fixed to, the carrier-hub 8.
• a worm a is mounted at the ends of the arms 5 and 6 on a lay-shaft 3 c ej extending transversely of the axis x-x, the worm a being engaged with the worm-wheel b carried by the shaft I.
• the combination of worm and worm-wheel has a ratio of 10 : I , that is 10 revolutions of the worm will produce one revolution of the worm-wheel.
• the carrier arms 5 and 6 also support an electric motor 9 having a drive shaft 4 extending through the carrier arm 6 and carrying a spu -gear c which is engaged with a spur-gear c on the lay shaft 3.
• the worm a and the spur-gear d are integral with or fixed to the loy shaft 3 which is freely rotatable about axis Y-Y in bearings provided in the carrier arms 5 and 6.
• the spur-gear c is integral with, or fixed to, the motor drive shaft 4 which in rotatable about axis Z-Z.
• the spur-gear d has 16 teeth, whilst spur-gear c has 80 teeth, so that one revolution of gear c will cause gear d to rotate 5.5625 revolutions.
• the lead angle between the worm a and worm-wheel b is selected to be a "locking angle", that is an angle between about 5 degrees and 15 degrees. With such a lead angle, it is possible to drive the worm-wheel b by rotating the worm a, but impossible to drive the worm a by rotating the worm wheel b. Consequently, upon rotation of the first shaft I in the direction R in Figure I the worm-wheel b will lock with the worm a and cause the carrier structure together with the second shaft 2 to rotate en masse with the shaft I in the direction R.
• the driving of the worm a by the electric motor 9 varies the transmission ratio between the shafts I and 2 depending upon the speed at which the electric motor 9 is rotated.
• the electric motor 9 were driven at a speed to drive the worm a at 10 revolutions per revolution of the worm wheel b in the directions indicated, then the rotation of the shaft I would not be transmitted to the carrier and the shaft 2 which would remain stationary.
• shaft 2 is loaded, i.e. is subject to some resistance to rotation, it will be possible to rotate shaft I at I I 1 2.5 rpm without any rot ⁇ tion being transmitted to shaft 2, assuming that the motor 9 is running at 2000 rpm. From this zero coupling condition, power can gradually be applied to shaft 2 by gradually reducing the power to motor 9 and thus effecting a gradual engagement of the shafts I and 2, culminating in a fully ⁇ coupled condition when the motor is fully de-energised and the shaft 2 rotates at the same speed as the shaft I .
• the worm wheel b and shaft I are stationary and power is provided to the motor 9, the worm a would orbit or "walk” around the worm-wheel b at a 5 : I rate of advantage. If this is done with the motor providing an
• the phase of the rotation of the shaft 2 can be advanced or retarded relative to the
• shaft I acts as an input shaft and shaft 2 as an output shaft
• either shaft can, in fact, assume the role of input or output.
• the invention also finds application in transmissions, where the assembly can provide a clutching action which can also provide advance/retard characteristics once the basic clutching action has been ⁇ c completed or partially completed. For example, if full engagement with a
• power may be fed to the motor 9 in order to rotate the worm a in a direction so as to drive the shaft 2 faster than shaft -5-
• the supply could be split betwee main motor driving the shaft I and the secondary motor 9.
• the shaft I is provided with a fixed (say 4 : 1 ) coupl between worm-wheel b and a power source driving the shaft I , once power source has been driven up to its maximum revolutions (say 8000 rp thereby providing 2000 rpm rotation of shaft I , then the shaft 1 could slowed down by energising the motor 9.
• the electric motor 9 of the described embodiments could, of cou be replaced by a hydraulic motor or pump, with a pressure regula hydraulic supply being the prime mover for the worm a.
• the drive sprocket the camshaft could be attached to one of shafts I and 2 and the camsh could be constituted by or attached to the other of the sha
• a drive assembly embodying the invention could be connec between the crankshaft and its output pulley or gear, thereby leaving camshaft totally standard, if desired.
• gearing is inclu between the motor 9 and the worm a.
• the assembly employ a direct drive from the electric motor to the lay-shaft 3, with motor and lay-shaft being in-line.
• the motor 9 could disposed parallel to the output shaft 2 with a flexible or angled coupling the worm by means of cables or gears.
• motor 9 could be mounted concentrically within the worm with a station rotor and a driven outer case integral with, or attached to, the worm a.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Gear Transmission (AREA)
• Valve Device For Special Equipments (AREA)
• Transmission Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10587901

Family Applications (1)

Country Status (5)

Families Citing this family (6)

Family Cites Families (7)

• 1985
  • 1985-11-07 GB GB858527525A patent/GB8527525D0/en active Pending
• 1986
  • 1986-11-06 EP EP19860906412 patent/EP0245344A1/de active Pending
  • 1986-11-06 GB GB08626536A patent/GB2182736A/en not_active Withdrawn
  • 1986-11-06 WO PCT/GB1986/000687 patent/WO1987003055A1/en not_active Ceased
  • 1986-11-06 AU AU65931/86A patent/AU6593186A/en not_active Abandoned
  • 1986-11-07 CN CN86107529A patent/CN86107529A/zh active Pending

Non-Patent Citations (1)

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