Abstract: There is provided a hydraulic pressure control device for an automatic transmission having a fail-safe mechanism to cope with an operation malfunction of electromagnetic valves. A first changeover valve that can be switched between a normal state where a drain port EX of each electromagnetic valve communicates with a predetermined drain destination and a failure state where the drain port EX and a predetermined hydraulic oil supply passage is disposed in a drain oil passage of clutches C1 and C2, and a second changeover valve that can be switched between a normal state where a supply port IN of each electromagnetic valve communicates with a predetermined hydraulic oil supply passage and a failure state where the supply port IN communicates with a predetermined drain destination is disposed in a supply oil passage of the other engaging elements.

Abstract: A hydraulic control apparatus is improved in reliability during a garage shifting with reducing costs of the apparatus. An electronic control unit controls equalizing the shift pattern (on-off pattern) during a first garage shifting when a manual valve is shifted from the neutral position to a drive position to the shift pattern during a second garage shifting when the manual valve is shifted from the neutral position to the reverse position. A control valve unit controls the hydraulic pressure applied to a first engagement element during the first garage shifting while controlling the hydraulic pressure applied to a second engagement element during the second garage shifting.

Abstract: A hydraulic pressure control apparatus for an automatic transmission having plural engaging elements (a first engaging element and a second engaging element) includes plural control valves (a first control valve and a second control valve) controlling each engaging element by supplying controlled hydraulic pressure as output pressure, plural shift valves for switching an oil passage for the line pressure, a fail valve closing an input port and a fail output port thereof while the output pressure is supplied from the second control valve; wherein, once the line pressure is supplied to the control valve through a supply port and a drain port thereof, it outputs the line pressure from as output pressure, and once the line pressure is supplied to the fail valve through the input port and a release port thereof, it outputs the line pressure as output pressure.

Abstract: A headrest height adjusting apparatus includes: a basal member attached to a seatback and supporting a driving member; a movable member linked to a headrest and lifted up and down relative to the basal member; a transmitting member transmitting a driving force of the driving member to the movable member and lifting up and down the headrest linked to the movable member. The transmitting member having a frangible portion that leads a collapse of the transmitting member against an impact applied in a vertical direction between the driving member and the movable member and absorbs energy of the impact.

Abstract: A hydraulic pressure characteristic value setting method for an automatic transmission comprises processes; disengaging one of friction engaging elements, transmitting turbine rotation to one side of each of the friction engaging elements, securing the other side of each of the friction engaging elements, detecting variations of speed of the turbine rotation by means of a turbine rotation sensor, executing a learning of a hydraulic pressure characteristic value in accordance with at least variations in the speed of turbine rotations when a friction engaging element starts to be engaged, and disengaging the engaged friction engaging element when a predetermined guard condition has been fulfilled.

Abstract: An oil pressure control apparatus includes: a first latch circuit for maintaining a predetermined shift valve by oil pressure outputted through a first control valve when a predetermined high shift stage is established; and a second latch circuit for maintaining a predetermined shift valve by oil pressure outputted from the first corresponding control valve when a predetermined shift stage for a vehicle restart is established. In an automatic shift pattern, each control valve is operated to achieve an automatic shift mode by which a shift stage in the transmission is freely selected among plural forward shift stages. In the fixed shift pattern, an oil passage for supplying oil pressure of the hydraulic power source to a predetermined control valve via each shift valve is established to achieve a fixed shift mode by which a predetermined fixed forward shift stage is selected in the transmission.

Abstract: In an oil pressure control apparatus for an automatic transmission, a specific combination of ON and OFF states of shift valves is assigned to an automatic shift pattern for operating solenoid valves for each shift stage of an automatic shift mode. One of other combinations of the ON and OFF states of the shift valves is assigned to a first fixed shift pattern of a first forward shift stage at which two predetermined solenoid valves from among the solenoid valves are employed. The other one of the other combinations is assigned to a second fixed shift pattern of a second forward shift stage at which other solenoid valves from among the solenoid valves are employed, one of the first and second fixed shift patterns being selected in response to operations of the shift valves for driving a vehicle.

Abstract: An automatic transmission including plural friction engaging elements configures plural shift ranges based on combinations of each friction engaging element being in engaging or disengaging condition and a controlling unit for controlling the friction engaging elements to be in engaging or disengaging condition by controlling a hydraulic pressure applied.

Abstract: Under the learning mode during a vehicle stationary condition, an oil pressure of the friction engagement element for setting a standby oil pressure value is increased by a predetermined step pressure while a transmission input shaft rotational speed has been maintained, and a standby oil pressure is set for shifting the friction engagement element to an engagement side. A controlled value is verified whether it is within a predetermined range corresponding to the predetermined step pressure when a change of the input value due to decrease of the turbine rotational speed satisfies a predetermined condition. The controlled value is learned when the controlled value is within the predetermined range corresponding to the step pressure. A step pressure larger than the step pressure is set when the controlled value is beyond the predetermined range corresponding to the step pressure.

Abstract: In a hydraulic control system for an automatic transmission, a valve element of an accumulator closes communication between a pressure switch circuit and a detection circuit when a hydraulic pressure applied to the detection circuit is lower than a predetermined hydraulic pressure, and opens communication between the pressure switch circuit and the detection circuit when the applied pressure is higher than or equal to the predetermined hydraulic pressure. A switching element opens communication between one end of the pressure switch circuit and an exhaust circuit when the other end of the pressure switch circuit does not communicate with the detection circuit, and closes communication between the one end and the exhaust circuit when the other end communicates with the detection circuit.

Abstract: A hydraulic control apparatus is improved in reliability during a garage shifting with reducing costs of the apparatus. An electronic control unit controls equalizing the shift pattern (on-off pattern) during a first garage shifting when a manual valve is shifted from the neutral position to a drive position to the shift pattern during a second garage shifting when the manual valve is shifted from the neutral position to the reverse position. A control valve unit controls the hydraulic pressure applied to a first engagement element during the first garage shifting while controlling the hydraulic pressure applied to a second engagement element during the second garage shifting.

Abstract: An automatic transmission includes a plurality of frictional engagement elements for constructing plural shift stages with combinations of engagement and disengagement thereof, a control portion for controlling the engagement and the disengagement of the frictional engagement elements, a switching device switching to a learning mode for learning a precharge time, and a precharge time determination device. The precharge time determination device transits the frictional engagement elements to an engagement side by maintaining the hydraulic pressure for determining the precharge time at a first precharge pressure while maintaining input shaft rotational speed at the learning mode at a vehicle stop state. A first precharge time defined from a start of maintaining the first precharge pressure until variation of an input value assumes significant is obtained. And a second precharge time at a second precharge pressure is obtained to be set for learning by a predetermined formula.

Abstract: There is provided a circuit configuration which does not require an additional fail-safe mechanism caused by the addition of a changeover valve in a hydraulic pressure control device for an automatic transmission having a function to directly supply a line pressure and hold (lock) an engaging pressure by combinations of electromagnetic valves and changeover valves. A changeover valve 20 is disposed between an output port 12 and a feedback port 13 of a linear solenoid valve 10 of the hydraulic pressure control device for an automatic transmission.

Abstract: There is provided a hydraulic pressure control device for an automatic transmission having a fail-safe mechanism to cope with an operation malfunction of electromagnetic valves. A first changeover valve that can be switched between a normal state where a drain port EX of each electromagnetic valve communicates with a predetermined drain destination and a failure state where the drain port EX and a predetermined hydraulic oil supply passage is disposed in a drain oil passage of clutches C1 and C2, and a second changeover valve that can be switched between a normal state where a supply port IN of each electromagnetic valve communicates with a predetermined hydraulic oil supply passage and a failure state where the supply port IN communicates with a predetermined drain destination is disposed in a supply oil passage of the other engaging elements.

Abstract: An automatic transmission including plural friction engaging elements configures plural shift ranges based on combinations of each friction engaging element being in engaging or disengaging condition and a controlling unit for controlling the friction engaging elements to be in engaging or disengaging condition by controlling a hydraulic pressure applied.

Abstract: According to an aspect of the present invention, an automatic transmission includes plural friction engaging elements configures plural shift ranges based on combinations of each friction engaging element being in engaging or disengaging condition, a controlling unit for controlling the friction engaging elements to be in engaging or disengaging condition by controlling a hydraulic pressure applied.

Abstract: A hydraulic pressure characteristic value setting method for an automatic transmission comprises processes; disengaging one of friction engaging elements, transmitting turbine rotation to one side of each of the friction engaging elements, securing the other side of each of the friction engaging elements, detecting variations of speed of the turbine rotation by means of a turbine rotation sensor, executing a learning of a hydraulic pressure characteristic value in accordance with at least variations in the speed of turbine rotations when a friction engaging element starts to be engaged, and disengaging the engaged friction engaging element when a predetermined guard condition has been fulfilled.

Abstract: An automatic transmission system for a vehicle includes a rotational speed detector for detecting a variation of a rotation number of driving torque transmitting member when a friction engagement element, which has been disengaged based upon oil pressure controlled by a control unit, a side of which has been transmitted with the rotation of the driving torque transmitting member, and the other side of which is locked not to be rotated during the vehicle at a stationary condition, is controlled to be engaged, wherein an oil pressure characteristic value of the friction engagement element is learned by the control unit based upon the variation of the rotation number of the driving torque transmitting member when the friction engagement element is initially engaged.

Abstract: Under the learning mode during a vehicle stationary condition, an oil pressure of the friction engagement element for setting a standby oil pressure value is increased by a predetermined step pressure while a transmission input shaft rotational speed has been maintained, and a standby oil pressure is set for shifting the friction engagement element to an engagement side. A controlled value is verified whether it is within a predetermined range corresponding to the predetermined step pressure when a change of the input value due to decrease of the turbine rotational speed satisfies a predetermined condition. The controlled value is learned when the controlled value is within the predetermined range corresponding to the step pressure. A step pressure larger than the step pressure is set when the controlled value is beyond the predetermined range corresponding to the step pressure.

Abstract: An automatic transmission includes a plurality of frictional engagement elements for constructing plural shift stages with combinations of engagement and disengagement thereof, a control portion for controlling the engagement and the disengagement of the frictional engagement elements, a switching means switching to a learning mode for learning a precharge time, and a precharge time determination means. The precharge time determination means transits the frictional engagement elements to an engagement side by maintaining the hydraulic pressure for determining the precharge time at a first precharge pressure while maintaining input shaft rotational speed at the learning mode at a vehicle stop state. A first precharge time defined from a start of maintaining the first precharge pressure until variation of an input value assumes significant is obtained. And a second precharge time at a second precharge pressure is obtained to be set for learning by a predetermined formula.