A hydraulic control apparatus includes: a branch path that branches from a passage connected to an oil pump and equipment to which oil is supplied by the oil pump; an accumulator connected to the branch path to accumulate and discharge high-pressure oil supplied from the branch path; a check valve provided in an oil inlet path through which oil flows into the accumulator; a balance valve unit including a reference pressure chamber, a balance valve body that is biased toward an opening side by an opening compression spring, and a control pressure chamber; and a control solenoid that introduces or discharges the high-pressure oil into or from the control pressure chamber.

A brake device of a transmission according to the present invention includes: a rotary-side holding member including an inner peripheral surface having a cylindrical surface shape about an axis extending in a forward/rearward direction and configured to hold a rotary-side friction plate on the inner peripheral surface; a fixed-side holding member including an outer peripheral surface having a cylindrical surface shape about the axis extending in the forward/rearward direction and configured to hold a fixed-side friction plate on the outer peripheral surface; and a lubricating oil supply portion supplying lubricating oil to the fixed-side friction plate and the rotary-side friction plate. The fixed-side holding member is provided in a transmission casing so as not to rotate. The rotary-side holding member is provided in the transmission casing at a radially outer side of the fixed-side holding member and is rotatable about a central axis of the inner peripheral surface.

An electronic control device for controlling at least one rotatably arranged actuator includes electronic components, such as a device for the contact-free reception of electrical energy and the contact-free reception of signals, a device for generating magnetic fields, and a common housing that encloses the electronic components and assimilates them. The control device is rotatable and designed for attaching on or into a component rotating around a rotational axis.

Provided is an automatic transmission including: an input section to which power generated by a drive source is input; an output section configured to output a drive force; and a gear shifting mechanism configured to change a gear ratio. The power is input to the input section without intervention of a hydraulic power transmission device. The gear shifting mechanism includes a predetermined frictional engagement element for achieving a starting gear ratio of a vehicle. The frictional engagement element includes: a plurality of friction plates arranged with clearances therebetween; a piston movable between a releasing position where the friction plates are brought into a released state, and an engaging position where the friction plates are brought into an engaged state by pressing the friction plates; and an urging mechanism configured to urge the piston so that the piston abuts against the friction plates and the clearances are reduced.

An automatic transmission includes: a brake device including a friction plate set configured with fixation friction plates and rotation friction plates alternately arranged, a piston, and an oil pressure chamber supplied with oil pressure that moves the piston toward the friction plate set side; a first rotating member; and second and third rotating members arranged at both respective axial sides of the first rotating member and each having an outer diameter smaller than that of the first rotating member. The friction plate set and the oil pressure chamber are arranged at both respective axial sides of the first rotating member and also arranged at an outer periphery side of the second rotating member and at the outer periphery side of the third rotating member, respectively. The piston extends from the oil pressure chamber toward the friction plate set side through the outer periphery side of the first rotating member.

A transfer case includes primary and secondary output shafts, along with a secondary torque transfer mechanism and a locking mechanism, which are configured to selectively couple the primary and secondary output shafts. The secondary torque transfer mechanism comprises a sprocket coupled to the secondary output shaft, and a plate clutch coupled to the sprocket to selectively form a friction coupling with the primary output shaft. The locking mechanism selectively couples the primary output shaft to the sprocket, and includes a locking sleeve and an actuator that moves the locking sleeve between a first position and a second position. In the first position, the locking sleeve forms a first splined connection with the primary output shaft and forms a second splined connection with the sprocket. In the second position, the locking sleeve forms the first splined connection with the primary output shaft and forms a second splined connection with the sprocket.

A transmission system includes planetary gearing with a ring gear, a plurality of planet gears, a carrier, and a sun gear, a forward clutch operatively connected between the ring gear and carrier, a reverse brake operatively connected between the carrier and a rotationally fixed location, and a control subsystem to switch the transmission system between forward and reverse operational modes in the which the ring gear and the sun gear rotate in the same or opposite rotational directions, respectively. A control subsystem actuation stroke can actuate both the forward clutch and the reverse brake based on a common control signal.

The automatic transmission which includes a third brake element formed by a support member including a first cylindrical portion having a first sliding surface at an outer peripheral surface thereof, a second cylindrical portion having a second sliding surface at an inner peripheral surface thereof and a third cylindrical portion having a third sliding surface at an inner peripheral surface thereof, an inner side piston, inner edge portion of which is in contact with the first sliding surface and an outer edge portion of which is in contact with the second sliding surface and an outer side piston which includes a first piston cylindrical portion, outer edge of which is in contact with the second sliding surface over an entire periphery thereof and a second piston cylindrical portion, outer edge portion of which is in contact with the third sliding surface over an entire periphery thereof.

A hydraulic drive unit for use in a vehicle or other application incorporates a motor connected to a pump through a porting system and an output shaft driven by the motor. A mechanical brake is used to brake the motor, while a valve provides a hydraulic brake for preventing flow between the hydraulic motor and the hydraulic pump. A brake actuator is connected to both the mechanical brake and the hydraulic brake, whereby actuation of the brake actuator causes both the mechanical brake and the hydraulic brake to be actuated.

A system for locking and releasing a shifting position of a shifting element that is hydraulically actuatable by an actuating pressure is provided. The shifting element is arranged coaxially with a transmission shaft. The system includes a stop valve. The stop valve is subjectable to a control pressure that is separate from the actuating pressure of the shifting element. The stop valve is arranged radially inside the shifting element in the transmission housing.