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
  • F16H15/00—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by friction between rotary members
  • F16H15/48—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by friction between rotary members with members having orbital motion
  • F16H15/50—Gearings providing a continuous range of gear ratios
• • 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
  • F16H15/00—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by friction between rotary members
  • F16H15/02—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by friction between rotary members without members having orbital motion
  • F16H15/04—Gearings providing a continuous range of gear ratios
  • F16H15/06—Gearings providing a continuous range of gear ratios in which a member A of uniform effective diameter mounted on a shaft may co-operate with different parts of a member B
  • F16H15/16—Gearings providing a continuous range of gear ratios in which a member A of uniform effective diameter mounted on a shaft may co-operate with different parts of a member B in which the member B has a conical friction surface

Definitions

• This invention relates to continuously variable traction drive transmissions and more particularly, it concerns improvements in torque transmitting bodies for such transmissions as well as in a method and structure for forcing complementary rolling surfaces incorporated in such transmissions into frictional torque transmitting engagement with each other.
• alpha body identifies one of the three working bodies which is concentric with the primary or first transmission axis
• the .term “beta body” identifies another of the three working bodies which is supported by or from the alpha body to be concentric with a second transmission axis which is inclined with respect to and intersects the first or primary axis
• the term “omega body” identifies the last of the three working bodies which is concentric with the first axis and which is rotatable or not rotatable independently in relation to the alpha body.
• the biconical body in continuously variable transmissions of the general class represented by the aforementioned U.S. patents is an integral or one-piece member supported at opposite ends by radial bearings.
• the bearings do not restrict axial movement of the biconical body and preferably provide also for freedom of pivotal motion spherically about the respecti centers of bearing support.
• the biconical body is used as the nutatable beta body in transmissions of the class described, normal force components by which the rolling or traction surfaces on the biconical body are pressed into engagement with complementing rolling or traction surfaces of revolution of the omega body, which complementing surfaces are concentric with an axis inclined with respect to and intersecting the axis of the biconical body, one of the two bearings in which the biconical body is journalled is carried from the alpha body by an eccentric mechanism which operates to convert torque acting between the alpha body and the biconical beta body into a thrusting force in a radial plane perpendicular to the axis of the beta body.
• the thrusting force is oppose by a reaction at the traction surfaces of the omega body (or rings) .
• the reaction force results in an axial force component at one point of rolling friction contact which is opposed by an equal axial force at a second point of rolling friction contact between the biconical beta body and the omega body.
• the traction surfaces on the respective beta and omega bodies are urged together at two points of contact under equal normal force loading even though the original thrusting force is applied only at one end of the beta body.
• the arrangement of the normal force developing means enables the traction surfaces on the respective beta and omega bodies to be withdrawn from contact with each other.
• a primary object of the present invention is, therefore, the provision of an unique one-piece biconical body for transmissions of the class described together with an unique normal force developing mechanism and method by which traction surfaces on the biconical body are retained in rolling friction engagement with a complementing body at two diametrically opposite points of rolling friction contact.
• FIG. 1 is a longitudinal cross-sectional view through a transmission embodiment incorporating the present invention
• Fig. 2 is an enlarged fragmentary cross-section on line 2-2 of Fig. 1;
• Fig. 3 is a schematic side elevation illustrating force components developed in accordance with the present invention
• Figs. 4 and 5 are schematic diagrams depicting an operational characteristic of the invention.
• a biconical torque transmitting or beta body is shown incorporated in a continuously variable transmission unit having a frame 12, an input shaft 14 and an output shaft 16.
• a continuously variable transmission unit having a frame 12, an input shaft 14 and an output shaft 16.
• the input shaft 14 is connected as an integral shaft extension with an alpha body 18 supported in the frame 12 by bearings 20 and 22 for rotation about a first axis 24.
• the beta body 10 in turn, is supported from the alpha body 18 by bearings 26 and 28 to be rotatable on a second axis 30 inclined with respect to and intersecting the first axis 24 at a point S of axes intersection.
• Supported by and coupled against rotation with respect to the frame 12 are a pair of omega rings 32 and 34 which are capable of axial adjustment toward and away • from the point S of axes intersection.
• the rings 32 and 34 are coupled through the frame 12 as a single torque body and as such, constitute the omega body of the transmission shown.
• axial adjustment of the omega rings.32 and.34 is effected by one or more opposit pitched screws 36 rotatable by an external control (not shown) through gears 38 and 40 which are rotatable on axes fixed with respect to the frame 12.
• An additional control gear 42 rotatable with respect to the frame 12, is shown and in practice is used to synchronize rotation of the gear 40 with corresponding gears for additional sets of double pitched screws (not shown) .
• a pinion gear 44 connected 0 directly to the biconical beta body 10, meshes with a ring gear ⁇ 6 coupled directly with the output shaft 16. .. , - Consistent with the several transmission embodimen
• the biconical beta body 10 in the illustrated embodiment defines a pair of 5 external conical surfaces 48 and 50 to engage complementing internal traction surfaces 51 and 52 on the omega rings 32 and 34 at two diametrically opposite points of contact Pi and P2.
• the rotational 0 speed of the output shaft 16 is the product of both rotation of the alpha body 18 on the first axis 24, causing orbital or planetary movement of the pinion gear 44, and rotation of the pinion gear with the biconical beta body 10 on the axis o
• the biconical member 10 undergoes a nutational movement as a result of its being supported' on the second axis 30 by the alpha body 18.
• the biconical body 10 may be concentric with the first axis 24 as the omega body and coupled directly with an output shaft whereas the rings 32 and 34 are concentric with the second axis 30 as the beta body and, as such, carried in nutation by the equivalent of the alpha body 18.
• the structure and function of the biconical body 10 is equally applicable to either form of transmission in this general class.
• the biconical body 10 is an integral or one-piece structure shaped externally to provide the frusto-conical traction surfaces 48 and 50 and having axially extending hub formations 54 and 56 at opposite ends.
• the body 10 is hollow for reduced weight and to facilitate cooling.
• both hubs 54 and 56 are also hollow to provide fluid communication throughout the length of the body 10.
• the bearings 26 and 28 by which the body 10 is supported from the alpha body 18 are preferably hydrodynamic bearings supplied with lubrication by porting 58 and 60 within the .alpha body 18.
• Each of the bearings 26 and 28 includes an internal bushing or sleeve 62 on the interior of a spherical bearing pad 64.
• Each of the hubs 54 and 56 is, moreover, of a length greater than the length of the bushings 62 so that in the absence of any other restraint, the body 10 will be permitted sliding motion to a limited extent along the second axis 30.
• the spherical bearing pads 64 will, moreover, provide- a similar freedom from restraint against universal pivotal movement of either hub 54 or 56 about the spherical center of the pads 64. It will be appreciated, therefore, that while the bearings 26 and 28 support the beta body 10 for rotation relative to the alpha body 18, the body 10 is supported with freedom from axial restraint by the bearings along the second axis.30.
• the bearing 26 at one end of the beta body 10 is carried from the alpha body 18 by an eccentric member 66 having a flanged ring portion 68 to receive the spherical bearing pad 64 and a semicylindrical lobe-like portion 70.
• the eccentric member 66 fits within the a recess 72 in the alpha body which is shaped to define a semicylindrical bearing surface 74 which complements the circular peripheral portion 76 of the lobe-like formation 70.
• Both of the surfaces 74 and 76 are concentric with a point or axis 78 which is eccentric with respect to the first or primary transmission axis 24 on which the alpha body 18 is rotatable.
• the point or axis 78 is offset from a plane 80 containing both the first axis 24 and the second axis 30 by a distance d and in a direction from which torque is transmitted between the alpha body 18 and the. beta body 10.
• the point 78 is oriented with respect to the first axis 24 as if the alpha body 18 were driven in a clockwise direction of rotation in Fig. 2 or in a direction tending to move the point 78 toward the plane 80.
• the eccentric member 66 is positioned in the alpha body recess 72 to be located diametrically between a yieldable preload plunger 82 and a hydraulic retraction plunger 84.
• the preload plunger 82 is retained in engagement with the member 66 under the bias of a compression spring 86 whereas the plunger 84 is received in a chamber 88 to which hydraulic fluid may be introduced under pressure through porting 90.
• the thrusting force between the alpha body 18 and the beta body 10 is through only the bearing 26 or at one end of the beta body, this initial thrusting force is resolved into substantially equal normal foce loading components at the points Pi and P2 of rolling friction contact.
• the resolution of forces acting to retain the beta body rolling surfaces in engagement with those of the omega rings 32 and 34 may be appreciated by reference to Fig. 3 of the drawings.
• the initial thrusting force F is in the direction of the arrow so designated and, as such, is perpendicular to the second axis 30.
• the thrusting force is opposed by a reaction force

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Friction Gearing (AREA)
• Transmission Devices (AREA)

Applications Claiming Priority (1)

Publications (2)

Family

ID=22154352

Family Applications (1)

Country Status (7)

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• 1980
  • 1980-05-19 JP JP81500493A patent/JPS57500892A/ja active Pending
  • 1980-05-19 WO PCT/US1980/000583 patent/WO1981003366A1/en not_active Ceased
  • 1980-05-19 EP EP19810900275 patent/EP0052603A4/de not_active Withdrawn
  • 1980-05-19 DE DE803050385T patent/DE3050385A1/de not_active Withdrawn
  • 1980-05-19 GB GB8138446A patent/GB2087009B/en not_active Expired
• 1981
  • 1981-05-15 CA CA000377736A patent/CA1149642A/en not_active Expired
  • 1981-05-18 IT IT67663/81A patent/IT1144717B/it active

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