摘要:
Hydraulic pressure which is regulated by a pressure control valve (linear solenoid valve) is applied to a hydraulic servo of a brake which is actuated when an engine-brake is effected. When the engine-brake is effected, a hydraulic pressure which is modulated by a modulator valve controlled by the linear solenoid valve is applied to the brake hydraulic servo. The pressure control valve provides high hydraulic pressure when vehicle speed is high based on signals from a speed sensor, and provides low hydraulic pressure when vehicle speed is low based on signals from the speed sensor, so that an engine-brake force is adequately controlled in accordance with vehicle speed. Furthermore, if a foot brake sensor is employed, the hydraulic pressure in accordance with vehicle speed can be made low when the engine-brake is effected with the foot brake applied. Based on signals from a front wheel rotation sensor and a rear wheel rotation sensor, the control unit calculates a rotational difference, so that the engine-brake force can be made low when the rotational difference is large.
摘要:
A hydraulic control apparatus for controlling a shifting action of a hydraulically operated frictional coupling device of an automatic transmission connected to a vehicle engine, from a neutral position to a forward drive position, in response to an operation of a shift lever. The apparatus includes a shift control valve operable in response to the shift lever, between a position for supplying a fluid to the coupling device for engagement thereof, and a position for discharging the fluid from the coupling device for disengagement thereof, a flow control device for controlling a rate of flow of the fluid between the shift lever valve and the coupling device, a fail-safe fluid passage disposed between the shift lever valve and the coupling device, for fluid communication between the shift lever valve and the frictional coupling device, irrespective of an operating position of the flow control device, and a controller for controlling the flow control device so as to restrict the fluid flow into or from the coupling device after an engaging or disengaging action of the frictional coupling device is actually started.
摘要:
A supplying port connecting to a supplying-side hydraulic pressure is arranged in a lock-up control valve. When the lock-up relay valve is switched ON (right half position), a supplying hyraulic pressure is supplied to a second oil chamber through an oil passage, led to a first oil chamber through an orifice and drained to a draining hydraulic oil passage through the oil passage. At this state in the lock-up control valve an inner pressure of the first oil chamber operates on a chamber through the oil passage, while an inner pressure of the second oil chamber operates on a chamber through the oil passage, and a controlling pressure from a linear solenoid valve operates on the controlling chamber. When the controlling pressure from the controlling chamber decreases by a deceleration of a vehicle speed, a valve closes a draining oil port and a drain port and increases an inner pressure of the first oil chamber. At this state when the hydraulic pressure of the second oil chamber increases by the contraction of the outer configuration of a torque convertor by a decrease of the centrifugal force, the draining oil port is connected to the supplying port and the hydraulic pressure is supplied to the first oil chamber to increase the hydraulic pressure of the chamber.
摘要:
A shift control system for an automatic transmission including a first transmission assembly for changing gear ratios in accordance with the release or engagement of a first frictional engagement system and a second transmission assembly connected in series to the first transmission assembly for changing gear ratios in accordance with the engagement or release of a second frictional engagement system. It includes a decision system for deciding whether or not the automatic transmission should execute the gear changes and a time lag controller for making the time lag for the second frictional engagement system to be engaged shorter than the time lag for the second frictional engagement system to be engaged for another gear change when the automatic transmission is to execute the gear changes.
摘要:
A reverse-engaging condition is prevented by a reverse inhibit valve operated by the solenoid valve even if a shift lever is operated to a reverse range at forward running. A solenoid valve controlling a 1-2 shift valve is "OFF" when controlling a manual valve to a reverse range under 7 km/h of a vehical speed. The reverse inhibit valve is at a right-half position. Therefore, the hydraulic pressure from the reverse range port of the manual valve runs through oil passages and supplied to the hydraulic servos. At forward running over 7 km/h the solenoid valve is switched "ON", the reverse inhibit valve is switched to a left-half position and oil passages are isolated. When the solenoid valve is switched at forward running, a hydraulic pressure from a R range port of the manual valve does not operate on a difference of cross sectional areas of lands of the reverse inhibit valve, so that the reverse inhibit valve is kept at the right-half position together with a pressing force of a spring therein.
摘要:
A hydraulic breather for a valve body in an automatic transmission, in which is disposed hydraulic equipment, for example, linear solenoid valves. The breather separates oil in the oil pan from the oil in the hydraulilc equipment when the automatic transmission is at work while allowing clean oil from the oil pan to enter the hydraulic equipment when the automatic transmission is at rest. The breating hole is provided in the form of an oil passage extending from hydraulic equipment within the valve body and includes an open-end section disposed in an upper part of the valve body. The open-end is located at a point higher than the working oil level in the automatic transmission. When the automatic transmission is at work, oil in the oil pan is used to lubricate, so the oil level is at its lowest level and the open-end section is above that oil level and thereby connects with air space in the valve body. When the automatic transmission is at rest, the oil level in the oil pan rises and oil from the oil pan enters into the breathing hole.
摘要:
A separate plate for use in a valve body of an automatic transmission has a gasket bonded to each side of the separate plate. The gasket is provided with boxes which are different in configuration from bores provided in the separate plate. Bores are punched out in the separate plate and the gasket coated with an adhesive, separately from each other, and then the separate plate and the gasket are bonded together in one unit. Accordingly, it is possible to provide a separate plate having improved assembling efficiency and superior resistances to heat, oil and rupture.
摘要:
An accumulator back pressure control device for an automatic transmission regulates the accumulator back pressure when a shift valve is switched. For example, when up-shifting from first to second speed, when the second brake starts to engage by switching of a shift valve, the rotational speed of the input is varied to change the output torque of the transmission gear mechanism. By detecting the change in rotational speed with a sensor, a pressure control valve (linear solenoid) is controlled by signals from a control unit so that the control pressure is regulated at a desired time. Thus, for example, the change of hydraulic pressure at a control pressure port regulates the oil source pressure (line pressure) and applies such regulated pressure to the back pressure chamber of an accumulator to change the back pressure of the accumulator. When shifting from second to third speed, the back pressure of another accumulator is similarly controlled, and when shifting from third to fourth speed, the back pressure of still another accumulator is similarly controlled. When down-shifting, the operations are preformed in the same manner as described above.
摘要:
An oil pressure control system for an automatic transmission which is equipped with a clutch including: an oil chamber; a piston adapted to be moved forward by pressure oil fed to the oil chamber; a plurality of friction discs adapted to engage when thrust by the piston; and a check valve assembly adapted to be opened by a centrifugal force, to release the pressure oil from the oil chamber. The control system comprises: an oil passage for feeding and releasing the pressure oil to and from the oil chamber; a limiter for limiting the inflow of the pressure oil into the oil chamber via the oil passage; an idle revolution detector for detecting that the clutch is idly revolving, to output an output signal when it detects the idle revolution; and a command unit made responsive to the output signal of the detector for limiting the inflow of the pressure oil into the clutch via the oil passage.
摘要:
A linear solenoid valve apparatus for discharging foreign matter collected at the exhaust port by engaging the electromagnet of the linear solenoid valve. The apparatus includes a linear solenoid valve having a valve sleeve, a spool, a spring, and an electromagnet, and a modulator valve including an exhaust port in which foreign matter is collected. The electromagnet is energized by foreign matter discharging control, responsive to detection of lack of need for output pressure from the solenoid valve, so that the foreign matter is discharged from the exhaust port.