Abstract: A vehicle power transmission device includes: a continuously variable transmission including a primary pulley, a secondary pulley, and a transmission belt wound between the primary pulley and the secondary pulley; a belt running clutch of hydraulic type for transmitting power to the continuously variable transmission; and a hydraulic control circuit controlling the continuously variable transmission and the belt running clutch. The hydraulic control circuit includes a fail-safe valve switching a communication destination of an oil supply passage for supplying a hydraulic fluid to the belt running clutch to one of a first oil passage supplied with a control hydraulic pressure and a second oil passage supplied with a hydraulic pressure higher than the control hydraulic pressure, the fail-safe valve connecting the oil supply passage with the second oil passage when the fail-safe valve is switched to a failure position. The second oil passage is provided with an orifice.

Abstract: A hydraulic control unit of a vehicle drive system including an automatic transmission, and an oil pump device, includes: a first electromagnetic valve; a second electromagnetic valve; first and second oil passages; a third oil passage; a manual valve operated to connect and disconnect the first and third oil passages and a drain oil passage to and from each other, in response to an operation of a manually operated shifting device by a vehicle operator, such that the first oil passage is connected to the third oil passage when the shifting device is placed in a first operating position, while the first oil passage is connected to the drain oil passage when the shifting device is placed in a second operating position; an accumulator connected to the first oil passage; and a check valve provided in the second oil passage.

Abstract: A hydraulic control unit of a vehicle drive system including an automatic transmission, and an oil pump device, includes: a first electromagnetic valve; a second electromagnetic valve; first and second oil passages; a third oil passage; a manual valve operated to connect and disconnect the first and third oil passages and a drain oil passage to and from each other, in response to an operation of a manually operated shifting device by a vehicle operator, such that the first oil passage is connected to the third oil passage when the shifting device is placed in a first operating position, while the first oil passage is connected to the drain oil passage when the shifting device is placed in a second operating position; an accumulator connected to the first oil passage; and a check valve provided in the second oil passage.

Abstract: A hydraulic control device that includes a second solenoid valve that is capable of supplying a resisting pressure that maintains the switching valve in the non-reverse state against the reverse range pressure, wherein the switching valve is maintained in the non-reverse state by supplying the resisting pressure from the second solenoid valve while a travel range is switched to at least a reverse range during forward travel.

Abstract: A hydraulic control device where the engagement pressure which is supplied from the first solenoid valve is supplied to the synchronization mechanism in the case where the signal pressure is not supplied to the switching valve, and the engagement pressure which is supplied from the first solenoid valve is supplied to the engagement element and the source pressure is supplied to the synchronization mechanism as the engagement pressure in the case where the signal pressure is supplied to the switching valve.

Abstract: A hydraulic control device that includes a source pressure generating valve that generates a source pressure; a solenoid valve that can supply the engagement pressure based on the source pressure; and a supply pressure switching valve that can be switched between a first state where the supply pressure switching valve can supply the engagement pressure to the second engagement element and a second state where the supply pressure switching valve can supply the source pressure to the second engagement element, the supply pressure switching valve being in the first state when the solenoid valve is operating normally, and being switched to the second state in case of abnormality in the solenoid valve.

Abstract: A hydraulic control device for an automatic transmission where the spool is locked at the first position and the switching pressure can regulate the belt holding force of the primary pulley or the secondary pulley without switching a position of the spool when the engagement pressure is supplied to the second working oil chamber, and the spool is not locked at the first position and the switching pressure can switch the spool to the second position against the urging member when the engagement pressure is not supplied to the second working oil chamber.

Abstract: A vehicle power transmission device comprises: a continuously variable transmission configured to include a primary pulley, a secondary pulley, and a transmission belt wound between the primary pulley and the secondary pulley; a belt running clutch of hydraulic type for transmitting power to the continuously variable transmission; and a hydraulic control circuit controlling the continuously variable transmission and the belt running clutch, the hydraulic control circuit comprising a fail-safe valve switching a communication destination of an oil supply passage for supplying a hydraulic fluid to the belt running clutch to one of a first oil passage supplied with a control hydraulic pressure and a second oil passage supplied with a hydraulic pressure higher than the control hydraulic pressure, the fail-safe valve connecting the oil supply passage with the second oil passage when the fail-safe valve is switched to a failure position. The second oil passage is provided with an orifice.

Abstract: A hydraulic control device that includes a second solenoid valve that is capable of supplying a resisting pressure that maintains the switching valve in the non-reverse state against the reverse range pressure, wherein the switching valve is maintained in the non-reverse state by supplying the resisting pressure from the second solenoid valve while a travel range is switched to at least a reverse range during forward travel.

Abstract: A hydraulic control device that includes a source pressure generating valve that generates a source pressure; a solenoid valve that can supply the engagement pressure based on the source pressure; and a supply pressure switching valve that can be switched between a first state where the supply pressure switching valve can supply the engagement pressure to the second engagement element and a second state where the supply pressure switching valve can supply the source pressure to the second engagement element, the supply pressure switching valve being in the first state when the solenoid valve is operating normally, and being switched to the second state in case of abnormality in the solenoid valve.

Abstract: A hydraulic control device has: a modulator valve using oil pressure from a hydraulic source for adjusting a modulator pressure; driving and driven-side hydraulic actuator control valves controlling hydraulic oil from the source to driving and driven-side hydraulic actuators; a driving-side control oil pressure adjusting electromagnetic valve using the modulator pressure for outputting a control oil pressure controlling the driving-side control valve; and a driven-side control oil pressure adjusting electromagnetic valve for outputting a control oil pressure controlling the driven-side control valve, the hydraulic control device including a failsafe valve switched from a normal to a failure position based on a failure disabling electric control for the driving-side and driven-side electromagnetic valves, the modulator valve making the modulator pressure lower than a value at the normal position based on an output switching pressure generated due to switching the failsafe valve from the normal to the failure p

Abstract: A hydraulic control device for an automatic transmission where the spool is locked at the first position and the switching pressure can regulate the belt holding force of the primary pulley or the secondary pulley without switching a position of the spool when the engagement pressure is supplied to the second working oil chamber, and the spool is not locked at the first position and the switching pressure can switch the spool to the second position against the urging member when the engagement pressure is not supplied to the second working oil chamber.

Abstract: A hydraulic control device where the engagement pressure which is supplied from the first solenoid valve is supplied to the synchronization mechanism in the case where the signal pressure is not supplied to the switching valve, and the engagement pressure which is supplied from the first solenoid valve is supplied to the engagement element and the source pressure is supplied to the synchronization mechanism as the engagement pressure in the case where the signal pressure is supplied to the switching valve.

Abstract: A hydraulic control device has: a modulator valve using oil pressure from a hydraulic source for adjusting a modulator pressure; driving and driven-side hydraulic actuator control valves controlling hydraulic oil from the source to driving and driven-side hydraulic actuators; a driving-side control oil pressure adjusting electromagnetic valve using the modulator pressure for outputting a control oil pressure controlling the driving-side control valve; and a driven-side control oil pressure adjusting electromagnetic valve for outputting a control oil pressure controlling the driven-side control valve, the hydraulic control device including a failsafe valve switched from a normal to a failure position based on a failure disabling electric control for the driving-side and driven-side electromagnetic valves, the modulator valve making the modulator pressure lower than a value at the normal position based on an output switching pressure generated due to switching the failsafe valve from the normal to the failure p