Continuously variable transmission
View Patent ↗A continuously variable transmission is disclosed for use in rotationally or linearly powered machines and vehicles. The single axle transmission provides a simple manual shifting method for the user. An additional embodiment is disclosed which shifts automatically dependent upon the rotational speed of the wheel. Further, the practical commercialization of traction roller transmissions requires improvements in the reliability, ease of shifting, function and simplicity of the transmission. The disclosed transmission may be used in vehicles such as automobiles, motorcycles, and bicycles. The transmission may, for example, be driven by a power transfer mechanism such as a sprocket, gear, pulley or lever, optionally driving a one way clutch attached at one end of the main shaft.
1. A continuously variable transmission having a longitudinal axis, a drive side and an output side, comprising:
a plurality of power adjusters, the centers of which are located in a plane about the longitudinal axis, wherein each power adjuster has at least one central bore that defines an axis of rotation of the power adjuster;
a drive disc annularly rotatable about the longitudinal axis and contacting a first point on each of the power adjusters and having a first side facing the power adjusters and a second side facing away from the power adjusters;
a plurality of generally elongated spindles having two ends and a longitudinal axis, wherein each spindle is positioned in a bore of an associated one of the power adjusters and is adapted to tilt the associated power adjuster;
annular first and second stationary supports each having a first side facing the power adjusters and a second side facing away from the power adjusters, wherein each of the first sides have a concave surface, wherein the first stationary support is located between the power adjusters and the drive side of the transmission and the second stationary support is located between the power adjusters and the output side of the transmission;
a support member with generally cylindrical outside diameter, and having two ends, that is adapted to provide radial support for the power adjusters, and is further adapted to move axially as the transmission is shifted;
first and second convex shifting platforms, one located axially adjacent to each end of the support member, adapted to actuate axial movement of the support member and further adapted to actuate a shift in the axis of rotation of the power adjusters;
a plurality of spindle supports adapted to convert an axial motion of the shifting platforms to a corresponding radial motion of the spindle ends;
first and second annular contact bearings, adapted to provide axial thrust to the support member when the transmission is shifted;
at least one spacer having two ends and adapted to maintain a spatial relationship among the first and second stationary supports;
a plurality of spindle rollers having an inside diameter and an outside diameter, the inside diameter coaxially and rotatably positioned over a spindle and the outside diameter adapted to rotatably engage at least one stationary support;
an annular bearing disc rotatably mounted over the longitudinal axis on the drive side of the transmission between and adapted to absorb and transmit axial force to a transmission housing, and further adapted to provide a rotating surface, which is capable of transmitting torque to the drive disc;
a plurality of ramps rotatably mounted over the longitudinal axis of the transmission between the drive disc and the bearing disc and adapted to produce an axial force that is transmitted to the drive disc, and wherein the bearing disc is adapted to transmit torque to the ramps;
a plurality of ramp bearings rotatably mounted over the longitudinal axis of the transmission between the ramps and the drive disc and adapted to transmit torque and axial force from the ramps to the drive disc, and wherein the ramp bearings are positioned radially and angularly by a bearing cage; and
a rotating driving member rotatably mounted over the longitidunal axis of the transmission and adapted to apply torque to the bearing disc.
2. The transmission of claim 1 , further comprising a hub cap bearing rotatably mounted over the longitudinal axis of the transmission and adapted to provide for relative movement between the bearing disc and the housing, and further adapted to transmit axial force to the case.
3. The transmission of claim 1 , further comprising a disengagement mechanism located between the bearing disc and the drive disc, wherein the disengagement mechanism comprises at least one pawl and at least one ratchet, and wherein the disengagement mechanism is adapted to disengage the drive disc from the power adjusters.
4. The transmission of claim 1 , further comprising a plurality of stationary support rollers, at least one stationary support roller attached to each spindle support and adapted to contact the concave surface on a stationary support.
5. The transmission of claim 1 , further comprising a plurality of wheels, at least one wheel for each spindle support, that are attached to the spindle supports and rollingly engage a convex platform.
6. The transmission of claim 1 , wherein the housing is adapted to rotate and the power adjusters contact and transmit torque to the housing.
7. The transmission of claim 1 , wherein the housing does not rotate.
8. The transmission of claim 7 , further comprising an output drive disc rotatably mounted over the longitudinal axis of the transmission and adapted to contact and be rotated by the power adjusters.
9. The transmission of claim 8 , further comprising an annular case bearing, rotatably mounted over the longitudinal axis of the transmission and adapted to provide for relative movement between the output drive disc and the housing and to transmit axial force from the output drive disc to the housing.
10. The transmission of claim 9 , further comprising at least one spacer extension, wherein the at least one spacer extension prevents the stationary supports from rotating, and wherein the spacer extension is attached to a non-moving component and is positioned radially outward from the at least one spacer.
11. The transmission of claim 1 , further comprising a spring positioned on the drive side of the transmission, wherein the spring is adapted to force the drive disc against the power adjusters to ensure that the drive disc frictionally engages the power adjusters.
12. The transmission of claim 1 , further comprising at least two axial force generators, wherein the second axial force generator is capable of sharing axial force production with the ramps.
13. The transmission of claim 12 , wherein the second axial force generator is a screw and nut, wherein the screw and nut are rotatably mounted over the longitidunal axis of the transmission, wherein the screw and nut are capable of providing axial force to the drive disc.
14. The transmission of claim 12 , wherein the ramps provide the majority of axial force when the transmission is in low and the screw and nut provide the majority of axial force when the transmission is in high.
15. The transmission of claim 12 , wherein during a switch in axial force production between the at least two axial force generators, torque is capable of being split between the at least two axial force generators.
16. The transmission of claim 15 , wherein upon a split in torque between the two axial force generators, axial force is capable of changing at a gradual rate as the transmission is shifted.