A drum brake device for a vehicle includes a first brake shoe and a second brake shoe movably coupled to a back plate, and spaced apart from each other; a wheel cylinder positioned between one end of the first brake shoe and one end of the second brake shoe, and configured to expand the distance between the one end of the first brake shoe and the one end of the second brake shoe; and an actuator positioned between another end of the first brake shoe and another end of the second brake shoe, and configured to provide a driving force to expand the distance between the one end of the first brake shoe and the one end of the second brake shoes and to expand the distance between the another end of the first brake shoe and the another end of the second brake shoe.

An S-cam brake system having is disclosed. The system includes a roller assembly, an S-cam, a shoe, and an S-cam brake. The roller assembly is configured to allow relative movement between a roller and a roller pin. The roller assembly is interposed between the S-cam and the shoe. Relative movement between a roller and a roller pin can compensates a defect in machining the outer contact surface of the S-cam roller or a defect in concentricity of roller seating depressions of the shoe.

An S-cam brake system having is disclosed. The system includes a roller assembly, an S-cam, a shoe, and an S-cam brake. The roller assembly is configured to allow relative movement between a roller and a roller pin. The roller assembly is interposed between the S-cam and the shoe. Relative movement between a roller and a roller pin can compensates a defect in machining the outer contact surface of the S-cam roller or a defect in concentricity of roller seating depressions of the shoe.

An automatic transmission is provided with a brake including a hub member coupled to a transmission case, a drum member coupled to a given rotary member, friction plates, a piston configured to engage the friction plates, and a hydraulic chamber for engagement disposed radially inward of the hub member and to which hydraulic fluid for biasing the piston in an engaging direction is supplied. The piston includes a pressing part configured to press the friction plates, a hydraulic chamber for engagement forming part, and a coupling part coupling the pressing part to the hydraulic chamber for engagement and extending radially. The hub member includes spline parts with which the friction plates are spline-engaged. Notches are formed by cutting the coupling part of the piston so as to be spaced apart from each other in circumferential directions, and end parts of the spline parts in axial directions enter into the notches.

An automatic transmission is provided with a brake including a hub member coupled to a transmission case, a drum member coupled to a given rotary member, friction plates, a piston configured to engage the friction plates, and a hydraulic chamber for engagement disposed radially inward of the hub member and to which hydraulic fluid for biasing the piston in an engaging direction is supplied. The piston includes a pressing part configured to press the friction plates, a hydraulic chamber for engagement forming part, and a coupling part coupling the pressing part to the hydraulic chamber for engagement and extending radially. The hub member includes spline parts with which the friction plates are spline-engaged. Notches are formed by cutting the coupling part of the piston so as to be spaced apart from each other in circumferential directions, and end parts of the spline parts in axial directions enter into the notches.

The invention concerns a brake unit, in particular for use in utility vehicles, comprising an actuating element and a piston element, wherein the actuating element is displaceable along an actuation axis, wherein the piston element is displaceable along a piston axis and is secured against displacement transversely to the piston axis, wherein the actuation axis and the piston axis stand substantially transversely to each other, wherein the actuating element comprises an actuating face and wherein the piston element comprises a piston face, wherein a plurality of roller bodies is arranged between the actuating face and the piston face for transmission of an actuating force between the actuating element and the piston element.

The invention concerns a brake unit, in particular for use in utility vehicles, comprising an actuating element and a piston element, wherein the actuating element is displaceable along an actuation axis, wherein the piston element is displaceable along a piston axis and is secured against displacement transversely to the piston axis, wherein the actuation axis and the piston axis stand substantially transversely to each other, wherein the actuating element comprises an actuating face and wherein the piston element comprises a piston face, wherein a plurality of roller bodies is arranged between the actuating face and the piston face for transmission of an actuating force between the actuating element and the piston element.

An S-cam brake system having is disclosed. The system includes a roller assembly, an S-cam, a shoe, and an S-cam brake. The roller assembly is configured to allow relative movement between a roller and a roller pin. The roller assembly is interposed between the S-cam and the shoe. Relative movement between a roller and a roller pin can compensates a defect in machining the outer contact surface of the S-cam roller or a defect in concentricity of roller seating depressions of the shoe.

An S-cam brake system having is disclosed. The system includes a roller assembly, an S-cam, a shoe, and an S-cam brake. The roller assembly is configured to allow relative movement between a roller and a roller pin. The roller assembly is interposed between the S-cam and the shoe. Relative movement between a roller and a roller pin can compensates a defect in machining the outer contact surface of the S-cam roller or a defect in concentricity of roller seating depressions of the shoe.

A drum brake, in particular for a utility vehicle, has a brake drum, which is rotatably mounted about a rotational axis, and multiple brake shoes, which are mounted in a receiving area of the brake drum and each of which has a friction lining support and a friction lining arranged thereon. The brake shoes can be pressed against a brake drum casing inner surface, which is designed as a friction surface, in a radial direction relative to a rotational axis of the brake drum. The interior of the drum brake is equipped with a brake cylinder assembly which is rotationally fixed to an armature housing for actuating the brake shoes. A respective pressing wedge is arranged on the friction lining support face facing away from the friction lining. The pressing wedge lies on a wedge mechanism which can be moved in a parallel manner relative to the rotational axis of the brake drum. The wedge mechanism can be moved from a non-braking position into a braking position by moving the service brake piston of the brake cylinder assembly in a parallel manner relative to the rotational axis of the brake drum.