Control system for an automatic transmission

Claim 2

In automatic power transmission of a motor vehicle driven by an engine and having a drive shaft, a driven shaft, a plurality of planetary gear sets interposed between said drive and driven shafts for providing drive connection therebetween at different gear ratios, each of said plurality of planetary gear sets having rotary members, first and second free-wheeling units connected to at least two of said rotary members of said planetary gear sets for preventing rotations of said rotary members in one direction, and a plurality of friction elements for controlling relative motions of said rotary members of said planetary gear sets, said plurality of friction elements including two different second brakes and a low and reverse brake, one of said second brakes cooperating with said first free-wheeling unit and engageable to cause said first free-wheeling unit to provide free-wheeling action while the other one of said second brakes is engageable to prevent rotation of that rotary member which is connected to said first free-wheeling unit in any direction thereby to provide an engine braking action, and said low and reverse brake being engageable to prevent rotation of that rotary member which is connected to said second free-wheeling unit in any direction to provide an engine braking action, a control system comprising a source of fluid under pressure; a plurality of fluid pressure operated servo means selectively communicating with said source of fluid under pressure for controlling the actuation of said plurality of friction elements; a manual selector valve communicating with said source of fluid under pressure and having a Drive position, a II position and a I position; and first and second shift valves communicating with said manual selector valve and cooperating with each other for selectively admitting fluid under pressure from said source of fluid under pressure to said fluid pressure operated servo means for actuating respective friction elements; and first and second speed control valves communicating with said manual selector valve, said first speed control valve being hydraulically connected to said fluid pressure operated servo means for said low and reverse brake while said second speed control valve is hydraulically connected to said fluid pressure operated servo means for said second brakes, said first speed control valve having means movable to a position to provide fluid communication between said manual selector valve and said fluid pressure operated servo means for said low and reverse brake when said manual selector valve is set in its I position to provide an engine braking action, and said second speed control valve having means movable to one position to provide fluid communication between said manual selector valve and said fluid pressure operated servo means for said one of said second brakes when said manual selector valve is set in its Drive position to cause said first free-wheeling unit to provide freewheeling action and movable to another position to provide fluid communication between said manual selector valve and said fluid pressure operated servo means for said other one of said second brakes when said manual selector valve is set in its II position to provide an engine braking action.

Claim 3

In an automatic power transmission of a motor vehicle driven by an engine and having a drive shaft, a driven shaft, a plurality of planetary gear sets interposed between said drive and driven shafts for providing drive connection therebetween at different gear ratios, each of said plurality of planetary gear set having rotary members, first and second free-wheeling units connected to at least two of said rotary members of said planetary gear sets for preventing rotations of said rotary members in one direction, and a plurality of friction elements for controlling relative motion of said rotary members of said planetary gear sets, said plurality of friction elements including two different second brakes and a low and reverse brake, one of said second brakes cooperating with said first free-wheeling unit and engageable to cause said first free-wheeling unit to provide free-wheeling action while the other one of said second brakes is engageable to prevent rotation of said rotary member connected to said first free-wheeling unit in any direction thereby to provide an engine braking action, and said low and reverse brake being engageable to prevent rotation of that rotary member which is connected to said second free-wheeling unit in any direction to provide an engine braking action, a control system comprising a source of fluid under pressure; a plurality of fluid pressure operated servo means selectively communicating with said source of fluid under pressure for controlling the actuation of said plurality of friction elements; a manual selector valve communicating with said source of fluid under pressure and having a Drive position, a II position and a I position; and first and second shift valves communicating with said manual selector valve and cooperating with each other for selectively admitting fluid under pressure from said source of fluid under pressure to said fluid pressure operated servo means for actuating respective friction elements; and first and second speed control valves interposed between said manual selector valve and said servo means for said low and reverse brake and said second brakes for controlling the flow of fluid under pressure from said source of fluid under pressure to said servo means thereby to selectively provide free-wheeling action and engine braking action, said first speed control valve having a first port communicating with said manual selector valve, a second port communicating with said servo means for said low and reverse brake, a third port communicating with said manual selector valve to receive a fluid under pressure therefrom when said manual selector valve is set in its I position, a valve spool for controlling fluid communication between said first and second ports, and a spring means biasing said valve spool to a position to interrupt fluid communication between said first and second ports, said valve spool being movable to another position against the action of said spring means to provide fluid communication between said first and second ports in response to the fluid under pressure supplied to said third port, and said second speed control valve having a first port communicating with said manual selector valve, second port communicating with said servo means for said one of said second brakes, a third port communicating with said servo means for said other one of said second brakes, A fourth port communicating with said manual selector valve to receive a fluid under pressure therefrom when said manual selector valve is set in its Drive position, a valve spool for controlling fluid communications between said first and second ports and between said first and third ports, a spring means for biasing said valve spool of said second speed control valve to a position to provide fluid communication between said first and third ports, said valve spool of said second speed control valve being movable to another position against the action of said spring means of said second speed control valve to provide fluid communication between said first and second ports in response to the fluid under pressure supplied to said fourth port.

Claim 4

In an automatic power transmission of a motor vehicle driven by an engine and having a drive shaft, a driven shaft, a plurality of planetary gear sets interposed between said drive and driven shafts for providing drive connection therebetween at different gear ratios, each of said plurality of planetary gear set having rotary members, first and second free-wheeling units connected to at least two of said rotary members of said planetary gear sets for preventing rotations of said rotary members in one direction, and a plurality of friction elements for controlling relative motion of said rotary members of said planetary gear sets, said plurality of friction elements including two different second brakes and a low and reverse brake, one of said second brakes cooperating with said first free-wheeling unit and engageable to cause said first free-wheeling unit to provide free-wheeling action while the other one of said second brakes is engageable to prevent rotation of said rotary member connected to said first free-wheeling unit in any direction thereby to provide an engine braking action, and said low and reverse brake being engageable to prevent rotation of that rotary member which is connected to said second free-wheeling unit in any direction to provide an engine braking action, a control system comprising a source of fluid under pressure; a plurality of fluid pressure operated servo means selectively communicating with said source of fluid under pressure for controlling the actuation of said plurality of friction elements; a manual selector valve communicating with said source of fluid under pressure and having a Drive position, a II position and a I position; and first and second shift valves communicating with said manual selector valve and cooperating with each other for selectively admitting fluid under pressure from said source of fluid under pressure to said fluid pressure operated servo means for actuating respective friction elements; and first and second speed control valves interposed between said manual selector valve and said servo means for said low and reverse brake and said second brakes for controlling the flow of fluid under pressure from said source of fluid under pressure to said servo means thereby to selectively provide free-wheeling action and engine braking action, said first speed control valve having a first port communicating with said manual selector valve, a second port communicating with said servo means for said low and reverse brake, a third port communicating with said manual selector valve to receive a fluid under pressure therefrom when said manual selector valve is set in its I position, a valve spool for controlling fluid communication between said first and second ports, and a spring means biasing said valve spool to a position to interrupt fluid communication between said first and second ports, said valve spool being movable to another position against the action of said spring means to provide fluid communication between said first and second ports in response to the fluid under pressure supplied to said third port, and said second speed control valve having a first port communicating with said manual selector valve, second port communicating with said servo means for said one of said second brakes, a third port communicating with said servo means for said other one of said second brakes, A fourth port communicating with said manual selector valve to receive a fluid under pressure therefrom when said manual selector valve is set in its Drive position, a valve spool for controlling fluid communications between said first and second ports and between said first and third ports, a spring means for biasing said valve spool of said second speed control valve to a position to provide fluid communication between said first and third ports, said valve spool of said second speed control valve being movable to another position against the action of said spring means of said second speed control valve to provide fluid communication between said first and second ports in response to the fluid under pressure supplied to said fourth port.

Claim 5

In an automatic power transmission of a motor vehicle, driven by an engine the combination comprising a drive shaft; a driven shaft; a hydraulic torque converter having an impeller connected to said drive shaft, a rotor fixed to a turbine shaft which is in line with said drive and driven shafts, and a stator; first, second and third planetary gear sets interposed between said drive and driven shafts for providing drive connection therebetween at different gear ratios, each of said planetary gear sets having rotary members including an internally toothed ring gear, a carrier carrying at least one planet pinion meshing with said ring gear and a sun gear externally meshing with said planet pinion, said carrier of said first planetary gear set being connected to said driven shaft, said sun gears of said first, second and third planetary gear sets being connected to each other and to a brake drum, said ring gear of said second planetary gear set and said pinion carrier of said third planetary gear set being connected to each other and said ring gear of said third planetary gear set being connected to said driven shaft; a first free-wheeling unit connected to said pinion carrier of said second planetary gear set for preventing rotation of said pinion carrier of said second planetary gear set in one direction; a second free-wheeling unit connected to said ring gear of said second planetary gear set and said pinion carrier of said third planetary gear set for preventing rotations of said ring gear of said second planetary gear set and said pinion carrier of said third planetary gear set; a first friction clutch disposed between said turbine shaft and said brake drum for providing a drive connection therebetween when engaged, said first friction clutch having a servo mechanism into which a fluid under pressure is selectively supplied for engaging said first friction clutch; a second friction clutch disposed between said turbine shaft and said ring gear of said first planetary gear set for providing a drive connection therebetween when engaged, said second friction clutch having a servo mechanism into which a fluid under pressure is selectively supplied for engaging said second friction clutch; a first friction brake having a brake band adapted to act on said brake drum for holding said brake drum and said sun gears stationary and having a servo mechanism into which a fluid under pressure is selectively supplied for braking said sun gears; a second friction brake connected to said pinion carrier of said second planetary gear set through said free-wheeling unit adapted for providing a free-wheel driving when second friction brake is engaged, said second friction brake having a servo mechanism into which a fluid under pressure is selectively supplied for engaging said second friction brake; a third friction brake connected directly to said pinion carrier of said second planetary gear set for preventing rotation of said pinion carrier of said second planetary gear set in either direction when engaged thereby to effect an engine braking action, said third friction brake having a servo mechanism into which a fluid under pressure is supplied for engaging said third friction brake; a fourth friction brake connected to said ring gear of said second planetary gear set and to said pinion carrier of said third planetary gear set for preventing rotations of said ring gear of said second planetary gear set and said pinion carrier of said third planetary gear set in either directions when engaged thereby to provide an engine braking action; a source of fluid under pressure; a manual selector valve communicating with said source of fluid under pressure and having a plurality of different positions including a Drive position, a II position and a I position; first and second shift valves communicating with said manual selector valve and said servo mechanisms of said friction clutches and brakes, said shift valves cooperating with each other for delivering said fluid under pressure from said source of fluid under pressure to said servo mechanisms for selectively actuating said friction clutches and brakes to control relative motions of said rotary members of said first, second and third planetary gear sets; and first and second speed control valves communicating with said manual selector valve, said first speed control valve being hydraulically connected to said servo mechanism of said fourth friction brake while said second speed control valve is hydraulically connected to said servo mechanisms of said second and third friction brakes respectively, said first speed control valve having means movable to a position to provide fluid communication between said manual selector valve and said servo mechanism of said fourth friction brake when said manual selector valve is moved to its I position, and said second speed control valve having means movable to one position to provide fluid communication between said manual selector valve and said servo mechanism of said second friction brake when said manual selector valve is moved in its Drive position and movable to another position to provide fluid communication between said manual selector valve and said servo mechanism of said third friction brake when said manual selector valve is moved in its II position.

Claim 6

In an automatic power transmission of a motor vehicle, driven by an engine the combination comprising a drive shaft; a driven shaft; a hydraulic torque converter having an impeller connected to said drive shaft, a rotor fixed to a turbine shaft which is in line with said drive and driven shafts, and a stator; first, second and third planetary gear sets interposed between said drive and driven shafts for providing drive connection therebetween at different gear ratios, each of said planetary gear sets having rotary members including an internally toothed ring gear, a carrier carrying at least one planet pinion meshing with said ring gear and a sun gear externally meshing with said planet pinion, said carrier of said first planetary gear set being connected to said driven shaft, said sun gears of said first, second and third planetary gear sets being connected to each other and to a brake drum, said ring gear of said second planetary gear set and said pinion carrier of said third planetary gear set being connected to each other and said ring gear of said third planetary gear set being connected to said driven shaft; a first free-wheeling unit connected to said pinion carrier of said second planetary gear set for preventing rotation of said pinion carrier of said second planetary gear set in one direction; a second free-wheeling unit connected to said ring gear of said second planetary gear set and said pinion carrier of said third planetary gear set for preventing rotations of said ring gear of said second planetary gear set and said pinion carrier of said third planetary gear set; a first friction clutch disposed between said turbine shaft and said brake drum for providing a drive connection therebetween when engaged, said first friction clutch having a servo mechanism into which a fluid under pressure is selectively supplied for engaging said first friction clutch; a second friction clutch disposed between said turbine shaft and said ring gear of said first planetary gear set for providing a drive connection therebetween when engaged, said second friction clutch having a servo mechanism into which a fluid under pressure is selectively supplied for engaging said second friction clutch; a first friction brake having a brake band adapted to act on said brake drum for holding said brake drum and said sun gears stationary and having a servo mechanism into which a fluid under pressure is selectively supplied for braking said sun gears; a second friction brake connected to said pinion carrier of said second planetary gear set through said free-wheeling unit adapted for providing a free-wheel driving when second friction brake is engaged, said second friction brake having a servo mechanism into which a fluid under pressure is selectively supplied for engaging said second friction brake; a third friction brake connected directly to said pinion carrier of said second planetary gear set for preventing rotation of said pinion carrier of said second planetary gear set in either direction when engaged thereby to effect an engine braking action, said third friction brake having a servo mechanism into which a fluid under pressure is supplied for engaging said third friction brake; a fourth friction brake connected to said ring gear of said second planetary gear set and to said pinion carrier of said third planetary gear set for preventing rotations of said ring gear of said second planetary gear set and said pinion carrier of said third planetary gear set in either directions when engaged thereby to provide an engine braking action; a source of fluid under pressure; a manual selector valve communicating with said source of fluid under pressure and having a plurality of different positions including a Drive position, a II position and a I position; first and second shift valves communicating with said manual selector valve and said servo mechanisms of said friction clutches and brakes, said shift valves cooperating with each other for delivering said fluid under pressure from said source of fluid under pressure to said servo mechanisms for selectively actuating said friction clutches and brakes to control relative motions of said rotary members of said first, second and third planetary gear sets; and first and second speed control valves communicating with said manual selector valve, said first speed control valve being hydraulically connected to said servo mechanism of said fourth friction brake while said second speed control valve is hydraulically connected to said servo mechanisms of said second and third friction brakes respectively, said first speed control valve having means movable to a position to provide fluid communication between said manual selector valve and said servo mechanism of said fourth friction brake when said manual selector valve is moved to its I position, and said second speed control valve having means movable to one position to provide fluid communication between said manual selector valve and said servo mechanism of said second friction brake when said manual selector valve is moved in its Drive position and movable to another position to provide fluid communication between said manual selector valve and said servo mechanism of said third friction brake when said manual selector valve is moved in its II position.