Transmission with band clutch

Abstract

The invention relates to transmissions with band clutches. A transmission is provided having a housing, a plurality of planetary gear sets, a structural member, a sprocket member, an annular drum, a belt, and an actuator. The sprocket member is rotatably supported by the structural member. The annular drum is adjacent to the structural member and is continuously rotationally coupled to a member of one of the plurality of planetary gear sets. The belt surrounds the annular drum and includes at least a first position and a second position. In the first position the belt is substantially spaced from the drum, and in the second position the belt contacts the drum. The actuator selectively positions the belt between at least the first and second positions to transmit torque between the structural member and the annular drum.

Description

technical field

[0001] The present invention relates generally to multi-speed transmissions having multiple planetary gear sets and multiple torque-transmitting devices, and more particularly to transmissions having a band clutch used as one of the multiple torque-transmitting devices. Background technique

[0002] The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.

[0003] A typical multi-speed transmission uses a combination of friction clutches, planetary gear arrangements, and fixed interconnections to achieve multiple gear ratios. Friction clutches typically include a plurality of plates that engage each other to transmit torque. Plate friction clutches are usually tightly spaced and may have drag between the plates when the clutch is disengaged. The drag force in the plate friction clutch increases spin losses and reduces the efficiency of the transmission. Band clutches are...

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