Shift actuator valve having a pressure dead band

A valve assembly for actuating a synchronizer, the synchronizer moveable between a first engaged state, a second engaged state, and a neutral state, the valve assembly comprising:

• a valve body having a stop;
• a sleeve slidably disposed within the valve body, the sleeve defining a bore, wherein the sleeve is moveable between a first position wherein the sleeve is in contact with the stop and a second position;
• a valve slidably disposed within the valve body and within the bore of the sleeve, wherein the valve is sealingly engaged to the valve body and the sleeve and the valve is operatively associated with the synchronizer, wherein the valve includes a first valve end and a second valve end opposite the first valve end, and wherein the valve is moveable between a first position that places the synchronizer in the first engaged state, a second position that places the synchronizer in the second engaged state, and a third position that places the synchronizer in the neutral state;
• a first source of pressurized hydraulic fluid in communication with the first valve end, wherein the first source of pressurized hydraulic fluid is operable to provide pressurized hydraulic fluid in contact with the first valve end, and wherein the pressurized hydraulic fluid in contact with the first valve end creates a first force acting on the first valve end to bias the valve and the sleeve towards the first position;
• and
• a second source of pressurized hydraulic fluid in communication with the second valve end and with the sleeve, wherein the second source of pressurized hydraulic fluid is operable to communicate pressurized hydraulic fluid to contact the second valve end and the sleeve to create a second force on the second valve end and a third force on the sleeve,
• wherein the sleeve and the valve are each in the first position when the second force and the third force combined are less than the first force,
• wherein the sleeve is in the second position and the valve is in the third position when the second force and the third force combined are greater than the first force but the second force is less than or equal to the first force, and
• wherein the valve is in the first position when the second force is greater than the first force.

A valve assembly comprising:

• a valve body having a stop;
• a sleeve slidably disposed within the valve body, the sleeve having a sleeve contact surface, wherein the sleeve is moveable between a first position wherein the sleeve is in contact with the stop;
• a valve slidably disposed within the valve body and within the sleeve, wherein the valve includes a first valve contact surface and a second valve contact surface opposite the first valve contact surface, and wherein the valve is moveable between a plurality of positions;
• a first source of pressurized hydraulic fluid in communication with the first valve contact surface, wherein the first source of pressurized hydraulic fluid is operable to provide pressurized hydraulic fluid in contact with the first valve contact surface, and wherein the pressurized hydraulic fluid in contact with the first valve contact surface creates a constant force acting on the first valve contact surface to bias the valve and the sleeve away from the stop;
• and
• a second source of pressurized hydraulic fluid in communication with the second valve contact surface and with the sleeve contact surface, wherein the second source of pressurized hydraulic fluid is operable to communicate pressurized hydraulic fluid to contact the second valve contact surface and the sleeve contact surface,
• wherein a lower threshold of a pressure dead band is defined by the pressure on the combination of the sleeve contact surface and the second valve contact surface required to balance the constant force developed on the first valve contact surface when the sleeve is restricted from movement by the stop, and wherein an upper threshold of the pressure dead band is defined by the pressure on the second valve contact surface required to balance the constant force developed on the first valve contact surface when the sleeve is restricted from movement by the stop.