Double cam actuation system for CVT

A scissor-ramp mechanism for a Continuously Variable Transmission the scissor-ramp mechanism extending along a rotation axis, with the scissor-ramp mechanism being adapted for varying continuous its axial dimension, the scissor-ramp mechanism comprising:

• a first driving ring and a second driving ring that are coaxial, concentric to each other, and rotatable relative to one another around the rotation axis, each one of the first driving ring and the second driving ring comprising a driving abutting facet;
• and
• a driven ring rotatable around the rotation axis, the driven ring comprising driven abutting facets:
• wherein the driving abutting facets are adapted to abut against the driven abutting facets,
• wherein at least one abutting facet among the driving abutting facets and the driven abutting facets is provided by a first helicoidal ramp,
• wherein rotating the driving relative to one another exerts a contacting section of the abutting face vided by the first helicoidal ramp to migrate thereover, thereby changing the axial dimension of the scissor-ramp mechanism,
• wherein the driven ring comprises an outer-ring section and an inner-ring section each comprising an helicoidal axial face, wherein the helicoidal axial face of the outer-ring section comprises a first one of the abutting facets of the drive in ring and the helicoidal axial face of the inner-ring section comprises a second one of the abutting facets of the driven ring, and wherein the driven ring is made of a single component.

A scissor-ramp mechanism for a Continuously Variable Transmission (CVT), the scissor-ramp mechanism extending along a rotation axis, with the scissor-ramp mechanism being adapted for varying continuous its axial dimension, the scissor-ramp mechanism comprising:

• a first driving ring and a second driving ring that are coaxial, concentric to each other, and rotatable relative to one another around the rotation axis, each one of the first driving ring and the second driving ring comprising a driving abutting facet;
• and
• a driven ring rotatable around the rotation axis, the driven ring comprising driven abutting facets,
• wherein the driving abutting facets are adapted to abut against the driven abutting facets,
• wherein at least one abutting facet among the driving abutting facets and the driven abutting facets is provided by a first helicoidal ramp,
• wherein rotating the driving rings relative to one another exerts a contacting section of the abutting facet provided by the first helicoidal ramp to migrate thereover, thereby changing the axial dimension of the scissor-ramp mechanism,
• wherein the driven ring comprises an outer-ring section and an inner-ring section each comprising an helicoidal axial face, wherein the helicoidal axial face of the outer-ring section comprises a first one of the abutting facets of the driven ring and the helicoidal axial face of the inner-ring section comprises a second one of the abutting facets of the driven ring,
• wherein the scissor-ramp mechanism is adapted to continuously adjust between a compact-most position and an extended-most position, and
• wherein the scissor-ramp mechanism further comprises biasing means biasing the scissor-ramp mechanism towards the compact-most position.

A method of operating a Continuously Variable Transmission (CVT) having a groove width constrained along a rotation axis, the method comprising:

• a) providing a scissor-ramp mechanism adapted to constrain the groove width, comprising:
• i) driving rings that are coaxial, concentric to each other, and rotatable relative to one another around the rotation axis, each one of the driving rings comprising a driving abutting facet;
• and
• ii) a driven ring rotatable around the rotation axis, the driven ring comprising driven abutting facets,
• wherein at least one abutting facet among the driving abutting facets and the driven abutting facets is provided by a first helicoidal ramp;
• b) rotating the driving rings one relative to another in a first spin direction through which the driving abutting facets are abutting against the driven abutting facets with a contacting section of the abutting facet provided by the first helicoidal ramp being exerted to migrate thereover in a first migrating direction, thereby increasing an axial dimension of the scissor-ramp mechanism and thereby causing the groove width to decrease,
• c) providing a biasing means adapted to bias the driven ring towards the driving rings;
• and
• d) rotating the driving rings one relative to another in a second spin direction such that the contacting section being exerted to migrate thereover in a second migrating direction by the biasing means, thereby decreasing the axial dimension of the scissor-ramp mechanism causing the groove width to increase.