Patent ID: 11940045
Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F | IPC F

Claim 1:
2. The power transmission apparatus according to claim 1,
wherein the automatic transmission defines a first power transmission path and a second power transmission path that are disposed in parallel to each other between the input shaft and the output shaft,
wherein the first power transmission path is provided by a gear power transmission device, a hydraulically-operated gear-forward-driving frictional engagement device, a hydraulically-operated gear-reverse-driving frictional engagement device and a hydraulically-operated synchronous-meshing engagement device that is disposed in series with the gear-forward-driving frictional engagement device and the gear-reverse-driving frictional engagement device, for enabling the forward driving and the reverse driving,
wherein the second power transmission path is provided by a belt continuously-variable transmission and a hydraulically-operated belt-driving frictional engagement device, for enabling the forward driving of the vehicle,
wherein the belt-driving frictional engagement device is the forward-driving engagement device while the gear-reverse-driving frictional engagement device is the reverse-driving engagement device,
wherein the hydraulic control unit includes, in addition to the first switching valve, the third switching valve, the failure switching valve, the lockup hydraulic control valve and the second hydraulic control valve, a second switching valve that is provided for switching the fluid paths and a first hydraulic control valve that is provided for controlling the hydraulic pressures,
wherein the first switching valve is configured, when being placed in the second connection state, to output the line pressure as an R-range pressure for the reverse driving of the vehicle, to the second switching valve,
wherein the third switching valve is configured, when being placed in the first connection state, to output the D-range pressure that is supplied with the first switching valve being placed in the first connection state thereof, to the second switching valve, and to output the line pressure to the lockup hydraulic control valve, and is configured, when being placed in the second connection state, to output the R-range pressure that is supplied through the second switching valve with the first switching valve being placed in the second connection state thereof, to the lockup hydraulic control valve,
wherein the second switching valve is configured, when being placed in a first connection state, to output the D-range pressure that is supplied with the first switching valve being placed in the first connection state thereof and with the third switching valve being placed in the first connection state thereof, to the failure switching valve, to output the line pressure to the first hydraulic control valve, to output a control pressure of the first hydraulic control valve to the synchronous-meshing engagement device, and to output the R-range pressure that is supplied with the first switching valve being placed in the second connection state thereof, to the third switching valve, and is configured, when being placed in a second connection state, to output the D-range pressure that is supplied with the first switching valve being placed in the first connection state thereof, to the failure switching valve, to output the D-range pressure that is supplied with the first switching valve being placed in the first connection state thereof and with the third switching valve being placed in the first connection state thereof, to the first hydraulic control valve, to output the control pressure of the first hydraulic control valve, to the failure switching valve, and to output the line pressure to the synchronous-meshing engagement device,
wherein the failure switching valve is configured, when being placed in the first connection state, to output the D-range pressure that is supplied with the first switching valve being placed in the first connection state thereof and with the second switching valve being placed in the second connection state thereof, and supplied with the first switching valve being placed in the first connection state thereof, with the third switching valve being placed in the first connection state thereof and with the second switching valve being placed in the first connection state, to the second hydraulic control valve, and to output the control pressure of the first hydraulic control valve that is supplied with the first switching valve being placed in the first connection state thereof, with the third switching valve being placed in the first connection state thereof and with the second switching valve being placed in the second connection state, to the gear-forward-driving frictional engagement device,
and wherein the control apparatus is configured, upon selection of a reverse range for the reverse driving of the vehicle in the event of the detection of the predetermined anomaly, to place the first switching valve in the second connection state thereof, place the second switching valve in the first connection state, place the third switching valve in the second connection state thereof, and to place the lockup hydraulic control valve and the first hydraulic control valve in hydraulic output states thereof.