Complex ramp in vehicle shift drum
AssigneeZhejiang CFMOTO Power Co., Ltd.
InventorXie Lebang
Life of this patent
Estimating the term…
Abstract
A shift drum has a recess which controls a fork to move one of two cooperating coaxially arranged gears for transmitting torque in a power train of a vehicle. The recess includes a straight section, which upon rotation of the shift drum does not move the fork either to the left or the right, and at least one ramp which does move the fork in one direction (i.e., to the left or the right). The ramp is more complex than a single line, such as having a first portion at a first right-shift portion ramp angle β and a second portion at a second right-shift portion ramp angle γ, perhaps with the intersection between the first right-shift portion ramp angle β and the second right-shift portion ramp angle γ being at the mid-line defined by the straight section of the recess.
Claims20
A shift drum for a fork to move one of two cooperating coaxially arranged gears for transmitting torque in a power train of a vehicle, the shift drum having a recess for receiving a control arm of the fork, wherein the recess comprises:
- a straight section, which upon rotation of the shift drum does not move the fork either to the left or the right;
- a first ramp, angled relative to the straight section, which upon rotation of the shift drum moves the fork in one direction;
- and
- a second ramp, angled relative to the straight section oppositely to the first ramp, which upon rotation of the shift drum moves the fork in the other direction, wherein the second ramp includes a first portion with a first portion ramp angle measured relative to the straight section and a second portion with a second portion ramp angle measured relative to the straight section, with the second portion ramp angle being shallower than the first portion ramp angle.
A gearbox for transferring power train torque of a vehicle, the gearbox being controllable by a gear selector, the gearbox comprising:
- a shift drum having a recess;
- a fork having a control arm received and sliding within the recess of the shift drum;
- a shaft carrying power train torque;
- a driving gear, axially moveable on the shaft, with its axial movement on the shaft controlled by the fork, the driving gear being rotationally secured to the shaft to transmit power train torque to or from the shaft;
- a driven high gear rotationally mounted on the shaft on one side of the driving gear;
- and
- a driven low gear rotationally mounted on the shaft on an opposing side of the driving gear;
- wherein the recess comprises:
- a straight section, which upon rotation of the shift drum does not move the fork either to the left or the right, the straight section establishing a mid-line in which the driving gear is not in engagement either with the driven high gear or the driven low gear;
- a first ramp, angled relative to the straight section, which upon rotation of the shift drum moves the fork in one direction, with the fork moving the driving gear into engagement with the driven high gear;
- and
- a second ramp, angled relative to the straight section oppositely to the first ramp, which upon rotation of the shift drum moves the fork in the other direction, with the fork moving the driving gear into engagement with the driven low gear, wherein the second ramp includes a first portion with a first portion ramp angle measured relative to the straight section and a second portion with a second portion ramp angle measured relative to the straight section, with the second portion ramp angle being different than the first portion ramp angle.
Dependencies are inferred from the claim text.