A clutching device of an automatic transmission includes: a clutch drum connected with a first rotation element, a clutch connected with the clutch drum and also a second rotation element, and a piston unit to operate the clutch. In particular, the piston unit includes: a first piston forming a first sealed space with the first rotation element and the clutch drum and moving toward the clutch to directly press the clutch by a hydraulic pressure supplied to the first space, a second piston forming a second sealed space with the first piston and the first rotation element, a spring retainer arranged on the first rotation element and forming a third sealed space with the first and second pistons and the first rotation element, a first return spring disposed between the first and second pistons, and a second return spring disposed between the spring retainer and the second piston.

A power delivery device configured for an automatic transmission may include a brake disposed between a rotation element connected to a brake hub and a transmission housing, and a piston device disposed corresponding to the brake and operating the brake by hydraulic pressure, wherein the power delivery device configured for an automatic transmission selectively connects the rotation element to the transmission housing by use of dual pistons.

A device for actuating a brake shoe of a brake, in particular a disk brake, includes a pivotably mountable lever element, and a transmission element configured to be mounted in a longitudinally movable fashion is such that a pivot movement of the lever element is translated into a longitudinal movement of the transmission element wherein a hydraulic chamber configured to be filled with a hydraulic fluid is arranged between the brake shoe and the transmission element for the transmission of force between the brake shoe and the transmission element.

Disclosed herein a hydraulic pressure supply apparatus of an electronic brake system includes a motor coupled to a modulator block having a flow path and a valve for adjusting braking hydraulic pressure therein, the motor having a stator and a rotor disposed to be spaced apart from an inner circumferential surface of the stator; a first gear configured to receive a rotational force from the rotor and rotating together with the rotor; a second gear provided with a piston on one side thereof and concentrically connected with the first gear in a ball screw manner to convert a rotational motion of the first gear into a linear motion; and an anti-rotation unit configured to prevent the second gear from rotating together with the first gear.

A brake of an automatic transmission includes: first and second recessed portions and formed in a center support; a first piston having a first pressure-receiving portion that is disposed in the first recessed portion and defines a first engagement oil chamber and having a plate-pressing portion that presses friction plates and separator plates; a second piston having a second pressure-receiving portion that is disposed in the second recessed portion and defines a second engagement oil chamber and a piston-pressing portion that presses the first piston by supply of oil pressure to the second engagement oil chamber; and a return spring that biases the first piston so that the first piston moves away from the friction plates and the separator plates.

A hydraulic brake includes: an inner pad and an outer pad located to sandwich a rotor configured to rotate with a wheel between the inner pad and the outer pad; a wheel cylinder including a cylinder body including a cylinder bore, a hydraulic pressure chamber formed in the cylinder body, and a first piston liquid-tightly and slidably fitted in the cylinder bore and configured to be moved by a hydraulic pressure in the hydraulic pressure chamber so as to press the inner pad against the rotor; and a drive member configured to be moved, by the hydraulic pressure in the hydraulic pressure chamber, in a direction opposite to a direction in which the first piston moves, so as to press the outer pad against the rotor. The cylinder body includes a fragile portion at a portion corresponding to the hydraulic pressure chamber.

A power delivery device configured for an automatic transmission may include a brake disposed between a rotation element connected to a brake hub and a transmission housing, and a piston device disposed corresponding to the brake and operating the brake by hydraulic pressure, wherein the power delivery device configured for an automatic transmission selectively connects the rotation element to the transmission housing by use of dual pistons.

The present disclosure relates to an electronic brake system. The electronic brake system includes a reservoir in which a pressurized medium is stored, an integrated master cylinder having a master chamber and a simulation chamber, a reservoir flow path provided to communicate the integrated master cylinder with the reservoir, a hydraulic pressure supply device provided to generate a hydraulic pressure by operating a hydraulic piston according to an electrical signal output in response to a displacement of the brake pedal, a hydraulic control unit including a first hydraulic circuit provided to control the hydraulic pressure to be transferred to two wheel cylinders, and a second hydraulic circuit provided to control the hydraulic pressure to be transferred to the other two wheel cylinders, and an electronic control unit configured to control valves based on hydraulic pressure information and displacement information of the brake pedal.

The present disclosure provides a brake apparatus comprising: a single monolithic brake shoe having a circular shape, wherein the shoe has a spacing defined therein at a predetermined location thereof; an actuator disposed in the spacing, wherein the actuator includes a hollow cylinder an a piston slidably contained in the cylinder, wherein when the actuator is activated, the spacing increases; and a brake lining lined on an outer face of the brake shoe, wherein when the spacing increases, the lining selectively contacts a brake drum, wherein the piston is step-shaped such that a braking force of the brake apparatus having the single monolithic brake shoe is substantially equal to a braking force of a brake apparatus having two individual brake shoes.

A dual action hydraulic clutch system. The system includes a master cylinder having an outer piston therein, wherein the outer piston includes a channel therethrough that can receive an inner piston therein. A gap is formed between the outer and inner pistons, such that activation of the outer piston activates the inner piston once the outer piston has traveled a length of the gap. The outer piston forces hydraulic fluid through an outer outlet connected to a hydraulic clutch, and the inner piston forces hydraulic fluid through an inner outlet connected to a rear brake, allowing a user to simultaneously disengage the clutch and engage the rear brake. A lever is connected to the outer piston, such that the lever can move the outer piston between a resting position, a clutch position, and a brake position. The master cylinder can secure to a support surface via a mounting bracket thereon.