Pumps

A transmission comprising:

• a hydrodynamic torque converter and a mechanical change-speed gear box downstream therefrom connected to the turbine shaft of the torque converter, said change-speed gear box having servomotors for selectively engaging the brakes and/or clutches therein to select different change speed ratios,
• and a fluid system for supplying pressurized fluid to the transmission comprising a first pump which operates continuously for supplying pressurized fluid to the working chamber of the torque converter, and a second pump, said second pump connected to the discharge side of the first pump via a one-way valve when the outlet side of the second pump exceeds by a predetermined amount the outlet pressure of the first pump, and a by-pass connecting channel from the outlet side of the second pump to the inlet side thereof, and a selectively openable shut-off valve in said by-pass connecting channel arranged such that when the shut-off valve of the by-pass connecting channel is open, fluid from the second pump does not supply fluid to the outlet side of the first pump, said by-pass channel and the maximum opening of the shut-off valve each having a flow cross-sectional area at least as great as the delivery flow cross-sectional area of the second pump, said shut-off valve being a disc valve which closes upon movement toward the inlet of the second pump, and a control device for controlling the opening of the shut-off valve independently of the pressure in the first and second pumps.

A transmission comprising:

• a hydrodynamic torque converter and a mechanical change-speed gear box downstream therefrom connected to the turbine shaft of the torque converter, said change-speed gear box having servomotors for selectively engaging the brakes and/or clutches therein to select different change speed ratios,
• and a fluid system for supplying pressurized fluid to the transmission comprising a first pump which operates continuously for supplying pressurized fluid to the working chamber of the torque converter, and a second pump, said second pump connected to the discharge side fo the first pump via a one-way valve when the outlet side of the second pump exceeds by a predetermined amount the outlet pressure of the first pump, and a by-pass connecting channel from the outlet side of the second pump to the inlet side thereof, and a selectively openable shut-off valve in said by-pass connecting channel arranged such that when the shut-off valve of the by-pass connecting channel is open, fluid from the second pump does not supply fluid to the outlet side of the first pump, an auxiliary high pressure pump having an outlet pressure greater than the first and second pumps, the inlet side of the high pressure pump being connected to the discharge side of the second pump, a first one-way valve permitting fluid flow from the outlet of the high pressure pump to the outlet side of the second pump at a predetermined pressure difference, and a second one-way valve permitting fluid flow from the outlet of the first pump to the outlet of the high pressure pump below a predetermined pressure difference, wherein fluid flows to the said servo-motors initially from the second pump, and thereafter the high pressure pump delivers its pressurized fluid to said servo-motors to selectively increase the pressure therein.

A transmission comprising:

• a hydrodynamic torque converter and a mechanical change-speed gear box downstream therefrom connected to the turbine shaft of the torque converter, said change-speed gear box having servomotors for selectively engaging the brakes and/or clutches therein to select different change speed ratios,
• and a fluid system for supplying pressurized fluid to the transmission comprising a first low pressure pump which operates continuously for supplying pressurized fluid to the working chamber of the torque converter and to the servomotors of the change-speed gear, and a second low pressure pump, said second low pressure pump connected to the discharge side of the first low pressure pump via a non-return valve when the outlet side of the second low pressure pump exceeds the outlet pressure of the first low pressure pump, and a by-pass connecting channel from the outlet side of the second low pressure pump to the inlet side thereof, and a selectively openable shut-off valve in said by-pass connecting channel arranged such that when the shut-off valve of the by-pass connecting channel is open, fluid from the second low pressure pump does not supply fluid to the outlet side of the first low pressure pump,
• said first and second low pressure pumps being gear pumps located side by side with the driving gears of each of said gear pumps being coaxial and connected to a common driving means, said driving means being driven by the turbine shaft of the torque converter,
• and including a high pressure pump having its inlet side connected to the outlet side of the second low pressure pump, said high pressure pump being a gear pump located in the same housing with said first and second low pressure pumps with its drive gear coaxial with and driven from the same source as the drive gears of the first and second low pressure pumps.

A transmission comprising:

• a hydrodynamic torque converter and a mechanical change-speed gear box downstream therefrom connected to the turbine shaft of the torque converter, said change-speed gear box having servomotors for selectively engaging the brakes and/or clutches therein to select different change speed ratios,
• and a fluid system for supplying pressurized fluid to the transmission comprising a first pump which operates continuously for supplying pressurized fluid to the working chamber of the torque converter, and a second pump, said second pump connected to the discharge side of the first pump via a one-way valve when the outlet side of the second pump exceeds by a predetermined amount the outlet pressure of the first pump, and a by-pass connecting chamber from the outlet side of the second pump to the inlet side thereof, and a selectively openable shutoff valve in said by-pass connecting channel arranged such that when the shut-off valve of the by-pass connecting channel is open, fluid from the second pump does not supply fluid to the outlet side of the first pump, and a control device for controlling the opening of the shut-off valve independently of the pressure in the first and second pumps, said first and second pumps being gear pumps located side by side with the driving gears of each of said gear pumps being coaxial and connected to a common driving means, said driving means being driven by the turbine shaft of the torque converter.