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US 5,014,565 AGranted
Variable ratio transmission
AssigneesPeter Stephenson, Jacobus Swanepoel
InventorPeter Stephenson
Life of this patent
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AssigneesPeter Stephenson, Jacobus Swanepoel
InventorPeter Stephenson
Estimating the term…
A variable ratio transmission unit includes at least one first transmission element mounted for rotation about a first axis, and at least one second transmission element in contact with the first element and mounted for rotation about a second axis. The first and second axes define a predetermined angle with each other. The first transmission element is generally disc shaped, with a profiled contact face on one major surface thereof, and the second transmission element is generally cylindrical, with a complementary profiled contact face on its periphery. The second element is slidable axially along the second axis to vary the distance between the point of contact of the elements and the first axis, to vary the effective transmission ratio. The first and second elements are so profiled that the common tangent at the point of contact between the elements passes through the point of intersection of the first and second axes irrespective of the axial position of the second element, and relative movement between the elements is substantially rolling movement. The transmission unit finds application in a vehicle transmission, in which a pair of the units are combined with an auxiliary gearbox to provide a steplessly variable friction drive transmission.
A variable ratio transmission unit including at least one first transmission element mounted for rotation about a first axis, and at least one second transmission element in contact with the first transmission element and mounted for rotation about a second axis which defines a predetermined angle with the first axis, the second transmission element being axially slidable along the second axis to vary the distance between the point of contact of the transmission elements and the first axis, thereby to vary the effective transmission ratio, the first and second transmission elements being provided with complementary profiled faces so that the common tangent with respect to the profiles of the transmission elements at the point of contact between the transmission elements passes through the point of intersection of the first and second axes irrespective of the axial position of the second transmission element, relative movement between the transmission elements being substantially rolling movement.
A variable ratio transmission unit including at least one first transmission element mounted for rotation about a first axis, and at least one second transmission element in contact with the first transmission element and mounted for rotation about a second axis which defines a predetermined angle with the first axis, the second transmission element being axially slidable along the second axis to vary the distance between the point of contact of the transmission elements and the first axis, thereby to vary the effective transmission ratio, the first and second transmission elements being provided with complementary profiled faces so that the common tangent with respect to the profiles of the transmission elements at the point of contact between the transmission elements passes through the point of intersection of the first and second axes irrespective of the axial position of the second transmission element, relative movement between the transmission elements being substantially rolling movement, wherein the transmission unit is driven by an internal combustion engine, a control signal being derived from an engine throttle setting or an equivalent setting and from a predetermined relationship between engine speed and throttle setting, so that the control signal causes the position of the second transmission element to be adjusted to maintain a substantially constant engine speed for a given throttle setting, independent of the output load on the transmission.
A transmission for a vehicle comprising first and second transmission units, each transmission unit including at least one first transmission element mounted for rotation about a first axis, and at least one second transmission element in contact with the first transmission element and mounted for rotation about a second axis which defines a predetermined angle with the first axis, the second transmission element being axially slidable along the second axis to vary the distance between the point of contact of the transmission elements and the first axis, thereby to vary the effective transmission ratio, the first and second transmission elements being provided with complementary profiled faces so that the common tangent with respect to the profiles of the transmission elements at the point of contact between the transmission elements passes through the point of intersection of the first and second axes irrespective of the axial position of the second transmission element, relative movement between the transmission elements being substantially rolling movement, the transmission units being arranged to be driven from a common input shaft, the outputs of the transmission units being passed to respective first and second intermediate output shafts, the second intermediate output shaft being arranged to rotate at a speed which is higher than that of the first intermediate output shaft by a factor equal to the ratio range of the transmission units, drive from one or the other of the intermediate output shafts being transmitted to a final output shaft via ones of a plurality of selectively engageable pinions associated with each intermediate output shaft.
Dependencies are inferred from the claim text.