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 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:
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 lock-up apparatus in a torque converter includes a first oil chamber (25) and a second oil chamber (26) delimited by a lock-up piston (21), a first oil line system (A) communicating with the first oil chamber (25), and a second oil line system (B) communicating with the second oil chamber (26). An orifice (36) and an oil line (37) for directly communicating the first oil line system (A) and the second oil chamber (26) are provided in an output shaft (20) and a turbine hub (19), respectively. Accordingly, the first oil chamber (25) and the second oil chamber (26) are not directly communicated. As a result, not only is shock produced at release from the locked up state mitigated by the orifice (36) and oil line (37), but it is also possible to reliably prevent a decline in transmission torque capacity in the lock-up ON state.
摘要:
A primary regulator valve has a cutback port which regulates a line pressure to increase, at the first speed of D range, a throttle pressure is applied to the cutback port through a cutback valve. The primary regulator valve sets the line pressure from a line pressure port higher. The cutback valve has a spool which is compressed in one direction. A first control chamber which is connected to a hydraulic servo (for example, a second brake hydraulic servo) which hydraulic pressure is applied at more than the second speed is formed against the pressing direction, a second control chamber which is connected to a hydraulic servo (for example, a second-coast brake hydraulic servo) to limit a coasting condition of the second speed is so formed as to follow the above pressing direction. At the second speed of second range, the cutback valve, as the first speed of D range, the throttle pressure is applied to the cutback port. Furthermore, the primary regulator valve has a control chamber which regulates the line pressure to decrease. A pressure control valve (for example, a linear solenoid valve to control a lock-up clutch) is connected to the control chamber to reduce the line pressure when a manual valve is selected from N range to D or R range.
摘要:
In a hydraulic control system for an automatic transmission comprising a hydraulic servomotor C-2 for a clutch or brake adapted to engage and disengage necessary rotary components of a planetary gear mechanism, and a select valve for selectively supplying hydraulic pressure to the hydraulic servomotor C-2 dependent on two transmission states, the select valve has two input ports selectively supplied with hydraulic pressure dependent on the two transmission states and one output port for outputting hydraulic pressure to the hydraulic servomotor C-2, a first orifice is disposed between the output port and the hydraulic servomotor C-2, and a second orifice is disposed on the same side as either of the two input ports.Upon an upshift from the 2nd to the 3rd speed in the D range condition, a shift valve is changed over such that the line pressure is supplied to one input port of the select valve via a line pressure output port and the second orifice to move a ball valve body in the select valve. Thus, the line pressure is supplied to the hydraulic servomotor C-2 via the output port of the select valve and the first orifice.In the R range condition, a manual valve is changed over such that its ports p and d are communicated with each other, while its port a is blocked off. The line pressure is hence supplied from the line pressure output port to another input port of the select valve for moving the ball valve body, so that the line pressure is supplied to the hydraulic servomotor C-2 via the first orifice.Therefore, at the time of an upshift from the 2nd to the 3rd speed, since the line pressure is supplied to the hydraulic servomotor C-2 while being restricted through both the second orifice and the first orifice, the clutch is gradually connected so as to prevent the occurrence of a shift shock. At the time of a shift into the reverse position, since the line pressure is supplied to the hydraulic servomotor C-2 while being restricted through only the first orifice, the clutch is more quickly connected so as to prevent a time lag in speed change.
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 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 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 control system in an automatic transmission for controlling the change-over of the three speed change patterns which are a speed change pattern having a cross gear ratio on a low speed side, a speed change pattern having a cross gear ratio on a high speed side and a speed change pattern having a normal gear ratio. According to this controlling system, when one of the three speed change pattern is selected based one a throttle opening and a vehicle speed, and when it is judged that the gear shift from a speed range in the present speed change pattern to a speed range in the selected speed change pattern falls under on of prohibited conditions, e.g., requiring engagement and/or disengagement of three or more frictional engaging elements for the gear shift, the gear shift is performed using a temporary speed change pattern (including the present speed change pattern) including a speed range not falling under the prohibited conditions. Thereafter, the pattern selection is repeated and the change-over between speed change pattern is performed under a gear shift condition not falling under the prohibited conditions.