Reverse shift control device on automatic transmission

In an automatic transmission of a vehicle having a transmission gear mechanism including a plurality of rotatable components and through which transmission gear mechanism power is transmitted in a respective one of power transmitting paths defined therethrough, frictional engaging means operatively connected to the transmission gear mechanism for selecting the power transmitting path through which power is transmitted in the transmission gear mechanism, said frictional engaging means including a third brake, hydraulic servos operatively connected to the frictional engaging means for operating or releasing or for engaging or disengaging the frictional engaging means, a plurality of shift valves operatively hydraulically connected to the hydraulic servos and a source of line pressure and which shift valves are movable between respective positions at which the line pressure is supplied toward the servos and respective positions at which the supply of line pressure is interrupted during forward travelling of the vehicle to provide different speeds which can be output by the transmission while the vehicle is travelling forward, and a manual valve operatively hydraulically connected in the transmission between the source of line pressure and the shift valves and which manual valve is settable to a plurality of ranges including reverse, a reverse shift control device comprising:

• a respective one of said shift valves that is movable to respective positions during forward travelling of the vehicle to provide different speeds which can be output by the transmission while the vehicle is travelling forward;
• said third brake being operatively connected to one of said components for braking a normal and a reverse rotation of said one of said components when said third brake is operated;
• said third brake being operated when the vehicle is travelling in reverse;
• one of the hydraulic servos to which said one of said shift valves is operatively hydraulically connected, said one of the hydraulic servos operatively connected to said third brake;
• said one of said shift valves having a first port in direct open hydraulic communication with said manual valve, line pressure being supplied directly to said first port from said manual valve when said manual valve is set to said reverse range, and said one of said shift valves having a second port in hydraulic communication with said one of the hydraulic servos, line pressure passing from said second port to said one of the hydraulic servos when said third brake operatively connected to said one of the hydraulic servos is to be operated,
• said one of said shift valves being movable between a first position at which said first and said second ports are open to one another and a second position at which said first and said second ports are closed to one another,
• solenoid valve means operatively connected to said one of said shift valves for causing said one of said shift valves to move between said positions thereof;
• and
• control means operatively connected to said solenoid valve means for controlling said solenoid valve means to cause said one of said shift valves to move to said second position thereof when said manual valve is set to said reverse range while the vehicle is travelling at a speed higher than a predetermined speed.