摘要:
A changeover valve (13) connected to a shift valve unit (12) via four oil passages L3-L6, and two pressure regulating valves (14.sub.1, 14.sub.2) are provided. At speed changing when the changeover valve (13) is in a first (right) position, an off-going hydraulic clutch is connected to oil passage L3 to control its pressure drop by the pressure regulating valve (14.sub.1) and an on-coming hydraulic clutch is connected to L5 to control its pressure rise by the pressure regulating valve (14.sub.2). After completion of the speed changing, the changeover valve (13) is switched to a second (left) position. At speed changing when the changeover valve (13) is in the second position, an on-coming hydraulic clutch is connected to L4 to control its pressure rise by the pressure regulating valve (14.sub.1) and an off-going hydraulic clutch is connected to the L6 to control its pressure drop by the pressure regulating valve (14). After completion of the speed changing, the changeover valve (13) is switched to the first position. After completion of the speed changing, oil at line pressure is supplied to the on-coming hydraulic clutch from the line pressure oil passage L2 without passing through the pressure regulating valves, and oil is discharged from the off-going hydraulic clutch without passing through the pressure regulating valves.
摘要:
A hydraulic control apparatus for a hydraulically operated vehicular transmission provided with hydraulic engaging elements has a control valve provided with a drain port, and oil discharge passages which are connected, at the time of disengagement of the hydraulic engaging elements, to working oil passages which are in communication with the hydraulic engaging elements. The hydraulic oil to be discharged from the drain port of the control valve is supplied to the oil discharge passages. The apparatus is provided with an oil reservoir for storing therein the hydraulic oil to be discharged from the drain port of the control valve. The oil discharge passages are connected to the oil reservoir.
摘要:
An automatic transmission comprises a forward/reverse selection hydraulic servomechanism 70 which actuates a dog clutch and a plurality of clutches 11, 12, 13, 14 and 15. For this automatic transmission, a control system comprises first˜fifth on/off solenoid valves 81˜85 and first˜third linear solenoid valves 86˜88. These valves are used to control the supply and drain of a line pressure to and from the forward/reverse selection hydraulic servomechanism 70 and first˜fifth shift valves 60, 62, 64, 66 and 68 so as to control the actuation thereof for the selective engagement of the clutches. This system, when it detects, by a hydraulic switch 93, a condition that the D range is selected and that the actuation command signals being sent to the solenoid valves correspond to one of the signal combinations which are used for setting the driving modes of the D range, allows the actuation of the solenoid valves by these actuation command signals.
摘要:
A control system for an automatic transmission comprises a forward/reverse selection hydraulic servomechanism 70, a D inhibitor valve, which controls the supply of a line pressure to the servo-oil chambers of this servomechanism, and a plurality of solenoid valves 81˜85, which are used for controlling the actuation of the shift valves and the D inhibitor valve. This control system comprises a first neutral mode and a second neutral mode for a neutral range. In the first neutral mode, the D inhibitor valve is switched to a forward drive position, and the forward drive servo-oil chamber is connected to a drain. In the second neutral mode, the D inhibitor valve is switched to a reverse drive position, and the forward drive and reverse drive servo-oil chambers are both connected to the drain.
摘要:
An automatic transmission comprises a plurality of clutches 11˜15, which are provided to select power transmission paths, respectively, in a parallel shaft speed change mechanism TM and a plurality of shift valves 60˜68, which are used for controlling the supply and drain of hydraulic oil to and from these clutches. For this automatic transmission, a control system comprises a plurality of solenoid valves 81˜85, which are used for controlling the supply and drain of a line pressure so as to control the actuation of these shift valves. This system, when the shift lever is manipulated to set the neutral range, sets the transmission into either a first neutral mode or a second neutral mode depending upon the speed of the vehicle, the first neutral mode being set when the vehicle is driving at a speed equal to or more than a critical speed, and the second neutral mode being set when the vehicle speed is less than the critical speed. In this control, the combination of on/off operations of the solenoid valves for setting the first neutral mode is different from the combination for setting the second neutral mode.
摘要:
An apparatus for controlling an oil pressure for a vehicular automatic transmission has an accumulator connected to an oil passage which is in communication with each of clutches for transmission or speed changing; a regulator valve for regulating an oil pressure to be supplied to the hydraulic clutches; a first pressure control valve of electromagnetic type for controlling an output oil pressure of the regulator valve by causing an oil pressure to act thereupon; and a second pressure control valve of electromagnetic type for controlling a back pressure of the accumulator. A drain port of one of the first and second pressure control valves is connected to an oil passage on an output side of the other of the pressure control valves.
摘要:
A hydraulic control circuit for a hydraulically operated vehicular transmission has at least five forward transmission trains. The hydraulic control circuit is made up of three sets of first through third solenoid valves and three sets of first through third shift valves to be controlled for changeover by the three sets of solenoid valves such that each of the transmission trains is established by changeover combinations of each of the shift valves. The first shift valve controls a condition of communication between an oil supply passage which is in communication with a hydraulic oil pressure source and a first oil passage and a second oil passage which are both on a downstream side of the oil supply passage. The second shift valve controls a condition of communication between the first oil passage and a third oil passage which is on a downstream side of the first oil passage and also controls a condition of communication between the second oil passage and a fourth oil passage and a fifth oil passage which are both on a downstream side of the second oil passage. The third shift valve controls a condition of communication between the fifth oil passage and a sixth oil passage and a seventh oil passage which are both on a downstream side of the fifth oil passage.
摘要:
A power transmitting apparatus for a vehicle mounted with a torque converter and an idle-stop mechanism can be configured to improve fuel economy without cancelling a fuel-cut-off during vehicle speed reduction and to reduce the manufacturing cost by eliminating an electrically-driven oil pump. A power transmitting apparatus can comprise a torque converter, a clutch mechanism, an oil pump, a continuously variable transmission, a clutch control device, an engine control device, and a flow control device. The flow control device can be configured to limit or prevent the supply of oil to the torque converter by the oil pump and to prioritize the supply of oil to the clutch mechanism and the continuously variable transmission when the vehicle speed is reduced below a predetermined value with fuel being cut off by the engine control device during vehicle speed reduction.
摘要:
A power transmitting apparatus with improved power transmitting efficiency and reduced lag time for shifting speeds can comprise a starting clutch mechanism configured to selectively transmit and cut off driving power of engine to wheels of a vehicle, a plurality of gear-stage clutch devices operatively positioned to transmit power between the starting clutch mechanism and the wheels, an input and an output of the plurality of gear-stage clutch devices configured at predetermined gear ratios, and a gear-stage selecting device configured to select any one of the gear-stage clutch devices in accordance with a vehicle operating condition and selectively set a gear ratio for power transmission from the engine to the wheels. The gear-stage clutch devices can comprise alternately arranged driving clutch discs and driven clutch discs, and hydraulic pistons. The hydraulic pistons can be configured to selectively engage or disengage the driving clutch discs and driven clutch discs such that driving power of the engine is transmitted to the wheels at a corresponding predetermined gear ratio when the driving clutch discs and driven clutch discs are engaged.
摘要:
A system for controlling an automatic transmission of a vehicle which determines a downgrade or upgrade parameter based on the vehicle acceleration and selects one from among a plurality of shift programs based on the determined grade parameter to determine a gear ratio based on the selected shift program. The system includes a navigation system which determines the instantaneous vehicle position and outputs road information including upgrade/downgrade condition of road including the determined instantaneous vehicle position. In the system, the grade parameter is corrected based on the navigation information and the grade parameter such that the one from among a plurality of shift programs is selected based on the corrected grade parameter, thereby enhancing drivability during downgrade running, without being affected even if the navigation information is temporarily invalid.