Transmission producing stepless variable speed ratios
A transmission includes a variator including a cone secured to an input, and a second cone driveably connected to the cone, producing a variable speed ratio between the cones, a gearset including a member secured to the second cone, and second and third members, a first clutch opening and closing a connection between the input and the second member, and a second clutch opening and closing a connection between an output and the third member.
1. A transmission, comprising:
a gearset including first, second and third members;
a variator including a cone secured to an input, a second cone secured to the first member and rotating in an opposite direction from a rotary direction of the cone, axial displacement of a ring along the cones producing a variable speed ratio;
a first clutch releasably connecting the input and the second member;
a second clutch releasably connecting the first and third members.
2. The transmission of claim 1 , wherein:
the variator further includes a ring engaging a surface of each cone, the speed ratio produced by the variator changing with movement of the ring along the surfaces of the cones.
3. The transmission of claim 1 , further comprising:
a first pinion secured to the input;
a first gear meshing with the first pinion, the first clutch connecting the input and the second member through the first pinion and the first gear.
4. The transmission of claim 3 , further comprising:
a second pinion journalled on the input;
a second gear meshing with the second pinion and secured to the second member; and
a third clutch opening and closing a connection between the input and the second member through the second pinion and the second gear.
5. The transmission of claim 1 , wherein:
the first member is a sun gear;
the second member is a carrier;
the third member is a ring gear; and
the gearset further comprises planet pinions supported on the carrier and meshing with the sun gear and the ring gear.
6. A transmission, comprising:
a gearset including first, second and third members;
a variator including a cone secured to an input, a second cone secured to the first member and rotating in an opposite direction from a rotary direction of the cone, axial displacement of a ring along the cones producing a variable speed ratio;
a first clutch releasably connecting the input and second member;
a second clutch releasably connecting the first member, an output and third member;
a third clutch releasably connecting the input and second member.
7. The transmission of claim 6 , wherein:
the first member is a sun gear;
the second member is a carrier;
the third member is a ring gear; and
the gearset further comprises planet pinions supported on the carrier and meshing with the sun gear and the ring gear.
8. The transmission of claim 6 , further comprising:
a first pinion secured to the input;
a first gear meshing with the first pinion, the first clutch connecting the input and the second member through the first pinion and the first gear.
9. The transmission of claim 8 , further comprising:
a second pinion journalled on the input;
a second gear meshing with the second pinion, the third clutch connecting the input and the second member through the second pinion and the second gear.
10. The transmission of claim 6 , wherein:
the variator further includes a ring engaging a surface of each cone, the speed ratio produced by the variator changing with movement of the ring along the surfaces of the cones.
11. A transmission, comprising:
a gearset including first, second and third members;
a variator including a cone secured to an input, and a second cone rotating in an opposite direction from a rotary direction of the cone, driveably connected by a ring to the cone and secured to the first member, axial displacement of the ring along the cones producing a variable speed ratio between the cones;
a first gearset comprising a pinion secured to the input, and a first gear meshing with the first pinion;
a first clutch releasably connecting the input and the second member through the first pinion and the first gear;
a second gearset comprising a second pinion concentric with the input, and a second gear meshing with the second pinion and concentric with the second member;
a second clutch releasably connecting the first member, an output and the third member;
a third clutch releasably connecting the input and the second member through the second gear and the second pinion.
12. The transmission of claim 11 , wherein:
the first member is a sun gear;
the second member is a carrier;
the third member is a ring gear; and
the gearset further comprises planet pinions supported on the carrier and meshing with the sun gear and the ring gear.
13. The transmission of claim 11 , wherein:
the variator further includes a ring engaging a surface of each cone, the speed ratio produced by the variator changing with movement of the ring along the surfaces of the cones.
14. A method for operation of a transmission, comprising:
securing a variator to an input, a sun gear of a gearset and a second clutch;
axially displacing a ring along the variator to vary a speed and rotary direction of the sun gear relative to the input;
using a first clutch to releasably connect an input and a carrier of the gearset; and
using the second clutch to releasably connect the sun gear and an output of the transmission.
15. The method of claim 14 , further comprising:
producing a low forward range by increasing the speed ratio of the variator.
16. The method of claim 14 , further comprising:
producing a high low forward drive range by using the first clutch to connect to the carrier of the gearset and using a second clutch to disconnect the output of the gearset from the output of the variator.
17. The method of claim 16 , further comprising:
producing a lower forward drive range by increasing a negative speed ratio of the variator.
18. The method of claim 17 , further comprising:
producing a reverse drive by further increasing the negative speed ratio of the variator.