Saturation of a secondary system pressure circuit (18) of a hydraulic system (4) of a motor vehicle transmission is earlier, in that an excess amount of oil from a primary system pressure circuit (16) of the hydraulic system (4) is not directed to a suction charging (40), but rather into the secondary system pressure circuit (18). This can take place via a system pressure valve (9) for the primary system pressure circuit (16), which is configured for this function.

An additive manufactured (AM) hydraulic control assembly includes an AM housing having a tubular wall defining a bore configured to receive at least one of a hydraulic valve and an accumulator, and a retainer clip configured to selectively secure to the AM housing such that the retainer clip is movable between a secured position that extends across at least a portion of the bore to retain the hydraulic valve or accumulator within the AM housing, and an unsecured position that enables the hydraulic valve or accumulator to be inserted into or removed from the bore.

A hydraulically actuatable shift element (100) includes a clutch piston (101), a fast fill piston (102), a fast fill valve (103), a fast fill pressure chamber (126), and a clutch pressure chamber (117). The fast fill valve (103) includes a sealing body (132) and a control body (131). Before the actuation of the shift element (100), the sealing body (132) is in a first switching position, in which the fast fill pressure chamber (126) is connected to a pressurized oil source (108) and, after the actuation of the shift element (100) in a second switching position, seals off the fast fill pressure chamber (126) with respect to the rest of the hydraulic system. The control body (131) has a first pressure surface (A18) and a second pressure surface (A19), wherein, in the first switching position, only the first pressure surface (A18) is pressurizable from the pressurized oil source (108). The fast fill valve (103) is configured such that, in the second switching position or between the first switching position and the second switching position of the control body (131), the second pressure surface (A19), in addition to the first pressure surface (A18), is pressurizable.

The control valve assembly is provided with a reinforcing portion straddling a drain port, the drain port allowing communication between an inside and an outside of the control valve assembly. The reinforcing portion is provided along a bore in which a spool of the control valve for control is housed. The control valve for control is a pressure regulator vale regulating a line pressure, the line pressure being a primary pressure of a hydraulic oil of the automatic transmission.

A transmission assembly for a hydrostatically or electrically propelled vehicle, comprising an input shaft, an output shaft, a first pair of gears and a second pair of gears, a synchroniser, a hydraulically operated actuator of the synchroniser which comprises a rod, and a hydraulic circuit for moving the rod, wherein the rod comprises an enlarged portion that is slidingly and sealingly housed in a respective portion of the seat so as to define two intermediate chambers. The actuator further comprises a contact element that is slidingly and sealingly housed in a relevant seat that is adjacent to the portion of the sliding seat so as to define a first end chamber, the contact element being able to move independently of the rod and defining an end point of the rod. A second end chamber is defined in an end of the rod that is opposite the enlarged portion.

A check valve assembly for controlling a flow of fluid in a transmission from a first cavity to a second cavity is disclosed. Check valve assembly may include a housing having a fluid passageway therein, a biasing member supported by the housing for axial movement along a first axis, and a valve element positioned within the fluid passageway of the housing. The valve element may be moveable between a seated position and an unseated position. An intersection of a plane normal to the first axis and the valve element defines a seating boundary of the element, which may define a minimum distance from the seating surface of the fluid passageway to the valve element when the valve element is in the unseated position. The check valve may include at least one swage extending radially inwardly from the fluid passageway to limit axial movement of the valve element.

A continuous variable transmission (CVT) hydraulic pressure control device includes: a pressure regulation valve regulating an operation pressure of oil supplied to a friction element of a forward-rearward device; and a switch valve to respectively switch oil discharge paths through which the oil supplied to the friction element is discharged, respectively by a pilot pressure from the pressure regulation valve and an elastic force of a return spring. In particular, the oil discharge paths switched by the switch valve have oil flow resistances different from each other.

A pressure regulator valve assembly for an automatic transmission includes a valve body, a valve chamber within the valve body, a valve piston disposed within the valve chamber, the valve piston having a valve channel, and a check valve disposed within the valve channel, the check valve is operable to permit fluid flow in the valve channel in a first direction and substantially prevent fluid flow in the valve channel in a second direction opposite to the first direction. An automatic transmission may include the pressure regulator valve assembly between a hydraulic pump and a torque converter, the pressure regulator valve assembly configured to control fluid flow between the hydraulic pump and the torque converter.

A hydraulic system is described, in particular for a motor vehicle transmission, with an actuator, a valve, a pressure supply line and a tank line. The actuator may have a first pressure chamber and a second pressure chamber, which can have pressure applied for actuation of the actuator, wherein the pressure chambers, the pressure supply line and the tank line are each connected to a port (A, B, P, T) of the valve. The valve may have several different switching positions, in which the pressure chambers with the pressure supply line or the tank line are selectively connected to each other or shut off from each other.

A hydraulic pressure control method for a transmission includes determining whether a current shift range is among a plurality of shift ranges, setting a dither frequency of a pressure control solenoid valve of a hydraulic circuit for the transmission to a predetermined first frequency when the current shift range is a predetermined first range, and setting the dither frequency of the pressure control solenoid valve to a predetermined second frequency when the current shift range is a shift range other than the first range.