A hydraulic control apparatus including a first and second control valves switched to exert hydraulic pressure on a piston to press toward first position, a third and fourth control valves switched to exert hydraulic pressure on the piston to press toward second position and, a CPU. The CPU performs executing a first process controlling the control valves so that hydraulic pressure is exerted by switching of the first, second and third control valves or a second process controlling the control valves so that hydraulic pressure is exerted by switching of the second control valve and determining that the first control valve is failed when movement of the piston to the first position is not detected through the first process and determining that the third control valve is failed when movement of the piston to the first position is not detected through the second process.

The present invention is a hydraulic pressure control device for an automatic transmission that performs a gear shift by switching between engagement and disengagement of a plurality of friction engagement elements and includes solenoid valves, provided corresponding to the friction engagement elements, respectively, that switches between engagement and disengagement of the friction engagement elements by switching between supply and non-supply of hydraulic pressures to the friction engagement elements, and a control device that switches between supply and non-supply of the hydraulic pressures to the friction engagement elements by supplying a predetermined control current to the solenoid valves, in which the control device supplies a fixation preventing current lower than the control current to at least one of the solenoid valves corresponding to the friction engagement elements in a disengagement state of the plurality of friction engagement elements.

Provided is a hydraulic control device in which in the rotation control of the second pump, the required discharge pressure of the second pump can be more reliably maintained below a predetermined pressure in the control that keeps the target rotation speed constant after the feedback control ends. In the rotation control of the second pump, in the control which keeps the target rotation speed constant after the feedback control ends, the rotation of the second pump is controlled by adding a predetermined addition rotation speed to the target rotation speed corresponding to the required discharge pressure. Since the required discharge pressure of the second pump can be maintained below a predetermined pressure in the fixed mode by the addition rotation speed, it can reliably obtain the effect of reducing the work load of the first pump and contribute to the improvement of the fuel efficiency of the vehicle.

A unitized valve body for use in an automatic transmission includes a plurality of valve bores and a plurality of hydraulic passages. Each valve bore is configured to receive a valve. The plurality of hydraulic passages are in fluid communication with the valve bores and arranged parallel to each other. The plurality of valve bores extend normal to the hydraulic passages and are arranged above and below the hydraulic passages.

A hydraulic parking lock actuation module for a parking lock with a parking lock piston, which can be hydraulically actuated in a parking lock cylinder from an initial position in an actuation direction by applying an actuation pressure, and which is mechanically coupled to an actuation rod which can be fixed via an engaging device in order to act as a locking mechanism for the parking lock piston. In order to simplify the actuation of the parking lock, for actuating the parking lock piston and the locking mechanism for the parking lock piston, the hydraulic parking lock actuation module includes only one active actuation valve with a tank connection and a working pressure connection at which different hydraulic pressure levels are applied.

A vehicle hydraulic control system comprises a high-low pressure decoupling valve, a high-pressure control oil circuit including a main pressure regulating pilot solenoid valve connected to a transmission controller and used for regulating the main oil pressure according to the instructions of the transmission controller and a main pressure regulating mechanical valve, a low-pressure cooling and lubricating oil circuit, a mechanical pump communication with the high-pressure control oil circuit, and an electronic pump is in communication with the high-pressure control oil circuit or the low-pressure cooling and lubricating oil circuit by means of the high-low pressure decoupling valve. The main pressure regulating mechanical valve is used for guiding the flow output by the electronic pump and/or the mechanical pump in communication with the high-pressure control oil circuit to the low-pressure cooling and lubricating oil circuit according to the control of the main pressure regulating pilot solenoid valve.

Ground wires are shared between a drive-side pulley solenoid valve and a driven-side pulley solenoid valve. Therefore, when a disconnection or short circuit occurs in the shared portion, a drive-side pulley and a driven-side pulley show substantially the same behavior. As a result, changes in the speed ratio γcvt of a continuously variable transmission are suppressed and changes in vehicle behavior are also suppressed. Therefore, it is possible to suppress the degradation of drivability during the failure of the solenoid valves involved in power transmission.

A unitized valve body for use in an automatic transmission includes a plurality of first hydraulic passages, a second hydraulic passage and a plurality of orifices. The second hydraulic passage extending through the unitized valve body and configured to be in fluid communication with a plurality of valve bores. Each orifice disposed within the unitized valve body and fluidly connecting the second hydraulic passage to a respective first hydraulic passage of the plurality of first hydraulic passages.

A unitized valve body for use in an automatic transmission includes a plurality of first hydraulic passages, a second hydraulic passage and a plurality of orifices. The second hydraulic passage extending through the unitized valve body and configured to be in fluid communication with a plurality of valve bores. Each orifice disposed within the unitized valve body and fluidly connecting the second hydraulic passage to a respective first hydraulic passage of the plurality of first hydraulic passages.

A unitized valve body for use in an automatic transmission includes a valve bore and an annulus. The valve bore is configured to receive a valve. The annulus is in fluid communication with the valve bore. The annulus defines an outer portion having an outer diameter and an innermost portion located at an interface between the valve bore and the valve. The outer portion having a first axial length and the innermost portion having a second axial length. The first axial length is greater than the second axial length.