Variable speed drive transmission

Claim 2

In a variable speed drive transmission including a drive shaft and a driven shaft with a ball and race frictional drive speed change mechanism having driving elements in frictional engagement drivingly interconnecting said shafts, a pressure regulator for automatically controlling contact drive pressures between said drive elements in accordance with the slippage between the drive elements and the torque loading of the driven shaft, said regulator comprising: a plurality of pistons positioned for reciprocation in sealed fluid cylinders; a coMmon fluid pressure chamber connected to said cylinders by valve means to receive the fluid pumped by said pistons, said common chamber being arranged to apply contact drive pressures to said drive elements in proportion to the fluid pressure in said chamber; cam means joined to said driven shaft and arranged with respect to said pistons to sequentially drive said pistons through uniformly spaced pumping strokes to pump fluid from said cylinders into said common chamber at a substantially uniform rate of flow; and fluid nozzle means in fluid communication with said common chamber to continuously bleed fluid from said chamber at a flow rate in accordance with the pressure in said chamber and the viscosity of the fluid flowing therethrough; whereby said pressure regulator includes a closed fluid system which accurately controls the flow rate and pressure of the fluid flowing into said common fluid chamber to thereby accurately vary the contact pressures between said drive elements.

Claim 3

A variable speed drive transmission in accordance with claim 1 wherein said cam means and pistons are arranged to reciprocate said pistons with a velocity which provides a uniform rate of flow of fluid from said piston cylinders into said common fluid chamber.

Claim 4

A variable speed drive transmission in accordance with claim 2 wherein said pistons comprise cylindrical pistons sealed in said fluid cylinders by piston ring sealing means, with each piston including rolling means engaged with said cam means and further wherein said cam means is provided with a profile which drives said rolling means along a substantially parabolic path, so that the relative rotation of said cam means with respect to said pistons reciprocates said pistons in a manner which produces a substantially constant total fluid displacement from said cylinders into said common fluid chamber.

Claim 5

A variable speed drive transmission in accordance with claim 1 wherein said valve means comprises check valves provided in fluid communication between said cylinders and said common chamber.

Claim 6

A variable speed drive transmission in accordance with claim 4 wherein said pistons are arranged in an annular array adjacent said common chamber and wherein said valve means comrises a resilient annular valve ring arranged in fluid communication between said chamber and each piston cylinder and operative as a one-way pressure-activated check valve permitting fluid flow from said cylinders into said common chamber.

Claim 7

In a variable speed drive transmission including a drive shaft and a driven shaft, a friction drive interconnecting said shafts including a plurality of drive balls in frictional driving engagement with a pair of coaxial input races connected to said drive shaft and a pair of coaxial output races connected to said driven shaft with one of said output races being joined for rotation with said driven shaft and the other of said output races being rotatable with respect to said driven shaft, a pressure regulator for automatically controlling contact drive pressures between said drive balls and races in accordance with the slippage between the drive balls and races and the torque loading of the driven shaft, said regulator comprising: means defining an expandable fluid chamber positioned to apply a varying axial force to said rotatable output race to thereby vary the contact pressures between said drive balls and races; a cylinder barrel coaxially positioned on and rotatable with respect to said driven shaft; a plurality of pistons positioned in sealed cylinders defined in said cylinder barrel in a uniformly spaced array about said output shaft; valve means connecting each of said cylinders to said fluid chamber; cam means joined to said driven shaft and arranged with respect to said pistons so that said piston barrel rotates with respect to said cam means to sequentially reciprocate said pistons axially with respect to said driven shaft, said cam means including a cam profile which drIves each of said pistons axially with a velocity which causes said pistons to pump fluid from said piston cylinders into said chamber at a substantially uniform rate of flow; and nozzle means in fluid communication with said common chamber to continuously bleed fluid from said chamber at a flow rate in accordance with the pressure in said chamber and the viscosity of the fluid flowing therethrough; whereby said pressure regulator includes a closed fluid system which accurately controls the flow rate and pressure of the fluid flowing into said common fluid chamber to thereby accurately vary the contact pressures between said drive balls and races.

Claim 8

In a variable speed drive transmission including a drive shaft and a driven shaft, a friction drive interconnecting said shafts including a plurality of drive balls in frictional driving engagement with a pair of coaxial input races connected to said drive shaft and a pair of coaxial output races connected to said driven shaft with one of said output races being joined for rotation with said driven shaft and the other of said output races being rotatable with respect to said driven shaft, a pressure regulator for automatically controlling contact drive pressures between said drive balls and races in accordance with the slippage between the drive balls and races and the torque loading of the driven shaft, said regulator comprising: means defining an expandable fluid chamber positioned to apply a varying axial force to said rotatable output race to thereby vary the contact pressures between said drive balls and races; a cylinder barrel coaxially positioned on and rotatable with respect to said driven shaft; a plurality of pistons positioned in sealed cylinders defined in said cylinder barrel in a uniformly spaced array about said output shaft; valve means connecting each of said cylinders to said fluid chamber; cam means joined to said driven shaft and arranged with respect to said pistons so that said piston barrel rotates with respect to said cam means to sequentially reciprocate said pistons axially with respect to said driven shaft, said cam means including a cam profile which drIves each of said pistons axially with a velocity which causes said pistons to pump fluid from said piston cylinders into said chamber at a substantially uniform rate of flow; and nozzle means in fluid communication with said common chamber to continuously bleed fluid from said chamber at a flow rate in accordance with the pressure in said chamber and the viscosity of the fluid flowing therethrough; whereby said pressure regulator includes a closed fluid system which accurately controls the flow rate and pressure of the fluid flowing into said common fluid chamber to thereby accurately vary the contact pressures between said drive balls and races.

Claim 9

A variable speed drive transmission in accordance with claim 6 wherein said pistons include rolling means engaged with said cam means and further wherein said cam profile is arranged to reciprocate each of said rolling means along a parabolic path so that the flow rate of fluid from said pistons into said common fluid chamber is uniform.

Claim 10

A variable speed drive transmission in accordance with claim 6 including eight axial pistons spaced uniformly in said piston barrel and wherein said cam means includes a plurality of axially-extending cam lobes spaced uniformly about said driven shafts and engagable with said pistons to reciprocate said pistons axially in said cylinder barrel.

Claim 11

A variable speed drive transmission in accordance with claim 8 wherein said cam means includes three uniformly spaced axially extending cam lobes having substantially equal lobe amplitudes and wave lengths.

Claim 12

A variable speed drive transmission in accordance with claim 9 wherein said valve means comprises an annular resilient valve ring arranged in fluid communication between said chamber and each piston cylinder and operative as a one-way pressure-activated check valve permitting fluid flow from said cylinders into said common chamber.