Abstract:
PROBLEM TO BE SOLVED: To provide a hydraulic control system of an automatic transmission for a hybrid vehicle having a valve body of simple constitution to improve responsiveness.SOLUTION: This hydraulic control system selectively starts first and second clutches and first and second brakes according to each traveling mode. The hydraulic control system includes: a first proportional control solenoid valve for selectively supplying forward pressure and reverse pressure supplied from a manual valve to the first clutch; a second proportional control solenoid valve for selectively supplying line pressure supplied from a primary regulator valve to the second clutch; a third proportional control solenoid valve for selectively supplying line pressure supplied from the primary regulator valve to the first brake; and a fourth proportional control solenoid valve for selectively supplying forward pressure supplied from the manual valve to the second brake.
Abstract:
There is provided a circuit configuration which does not require an additional fail-safe mechanism caused by the addition of a changeover valve in a hydraulic pressure control device for an automatic transmission having a function to directly supply a line pressure and hold (lock) an engaging pressure by combinations of electromagnetic valves and changeover valves. A changeover valve 20 is disposed between an output port 12 and a feedback port 13 of a linear solenoid valve 10 of the hydraulic pressure control device for an automatic transmission. The changeover valve 20 operates depending on at least an output pressure from the output port, and is switched between (1) a first state (control mode) in which a pressure Pc corresponding to an indicator current is outputted through the linear solenoid valve 10 by bringing the output port into communication with the feedback port, and (2) a second state (lock mode) in which a line pressure PL is outputted through the linear solenoid valve 10 by bringing the feedback port 13 into communication with a drain passage EX and discharging oil from the feedback port.
Abstract:
PROBLEM TO BE SOLVED: To provide a rotary introduction part producing only comparatively small leakage. SOLUTION: A first end range of a tubular section enters and engages with a hole 4 provided on a first construction section 1. A second end range of a tubular section 3 enters and engages with a hole 5 provided on a second construction section 2. The first end range of the tubular section 3 is sealed against an inner wall of the hole 4 of the first construction section 1 by a piston ring 9, and can freely rotate relatively to the first construction section 1. O-ring packing 7 is automatically secured on an inner wall of the hole 5 of the second construction section 2. The tubular section 3 rotates at same rotation speed as the second construction section 2. COPYRIGHT: (C)2008,JPO&INPIT
Abstract:
PROBLEM TO BE SOLVED: To cancel undesirable pressure induced in a fluid in a piston chamber with centrifugal force. SOLUTION: The present invention provides an improved fluid management system for a dual clutch assembly and a multiple clutch assembly, which has a fluid operated piston and a fluid operated balance chamber and is configured to cancel the undesirable pressure in a fluid in a piston chamber with centrifugal force. The especially important improvement is that the present system provides an efficient and cost-effective arrangement of a fluid supplying passage and a supply opening part, which can maintain a low flow amount, i.e., a fluid level required in the balance chamber even under a commonly insufficient flow amount state. In another embodiment, the present system provides a reservoir for the balance chamber for use under circumstances where the fluid flow is stopped or interrupted. COPYRIGHT: (C)2005,JPO&NCIPI
Abstract:
A pressure control apparatus and method are provided for controlling hydraulic clutches of a backward and forward drive switching device mounted in a transmission of a working vehicle such as a tractor. When a backward and forward drive switching shuttle lever is operated, a current supplied to an electromagnetic proportional valve is controlled to gradually increase the pressure for a hydraulic clutch corresponding to a direction of movement. When a propelling drive connecting and disconnecting clutch pedal is operated, the pressure for that hydraulic clutch is controlled through the electromagnetic proportion valve, based on a depressed position of the pedal. When the operator switches the shuttle lever from forward to backward or vice versa, a microcomputer causes the shuttle control current to rise at a point of time of start of a clutch engaging operation of the clutch pedal.
Abstract:
PURPOSE:To optionally adjust the pressure of a clutch, by providing a relief valve whose valve opening pressure set by a spring is changed in association with the displacement of a piston, and a means for electrically control the amount of working oil effected to the above-mentioned piston so that the relief pressure is applied to the clutch. CONSTITUTION:In the case of application of a hydraulic control valve for controlling clutch cylinders in a speed change clutch, a spool 3 having piston sections 4, 5 and a piston 8 positioned on the line coaxial with the spool 3 are disposed in a valve body 2 to constitute a variable relief valve 1, and oil chambers 6-10 are defined in the inside of a cylinder bore. The spring force of spring 19 disposed between the spool 3 and the piston 8 may be adjusted in association with the displacement of the piston 8. Further, a port 22 opened to the chamber 10 is communicated with a circuit in which a selector valve 24 using the hydraulic pressure in the chamber 6 as its pilot pressure, is connected in parallel to a series circuit composed of three solenoid valves 25, 27, 29 and three restrictors 26, 28, 30, and therefore, the displacements of the piston 8 may be adjusted in association with the opening and closing operation of the valves 24, 25, 27, 29.