A brake master cylinder comprising a housing having an inner surface defining a bore, and a piston movable in the bore along a piston axis. The piston includes two spaced apart lands defining the radially outermost surfaces capable of contacting the inner surface. At least one of the lands is longitudinally curved at the radially outermost surface. For example, the land can be curved at a radius of less than 1 inch (e.g., between 0.15 inch and 0/75 inch) and preferably less than 0.5 inch. In one embodiment, the longitudinally curved land includes two edges that define an axial length of the land. The two edges have a radius of less than 0.2 inch, and preferably about 0.1 inch. The relative position of the edges and lands is such that neither of the two edges is capable of contacting the inner surface of the bore during reciprocating movement of the piston in the bore.

A combination of piston rings assembled to a piston includes a first compression ring, a second compression ring, a third compression ring and an oil ring. When an axial width of the first compression ring is h1(1), an axial width of the second compression ring is h1(2), an axial width of the third compression ring is h1(3) and an axial width of the oil ring is h1(4), h1(1)?h1(2) and h1(1)?h1(3), and when h1(TOTAL)=h1(1)+h1(2)+h1(3)+h1(4), h1(TOTAL)?3.1 mm.

Steel plungers for hydraulic fracturing pumps having enhanced surface hardness properties, preferably made of alloyed steel and a method for manufacturing said plungers, comprising an ion nitriding process.

A master cylinder includes a piston seal installed in a circumferential groove. The piston seal includes an annular base section, an inner circumferential lip section protruding from an inner circumferential side of the base section to come in sliding contact with an outer circumferential surface of a piston, an outer circumferential lip section protruding from an outer circumferential side of the base section to abut the circumferential groove, and an intermediate protrusion section protruding from between the inner circumferential lip section and the outer circumferential lip section of the base section to a forward side of the outer circumferential lip section. A step difference section is formed at the outer circumferential side. The circumferential groove has a step section that always abuts an outer circumferential surface of the step difference section. A communication path configured to bring a supply path that is in communication with a reservoir and the bottom section side of the circumferential groove in communication with each other is formed between the step difference section and the step section.

An integrally formed piston has a crown portion having an upper crown surface and an undercrown surface. A ring belt extends from the undercrown surface at a periphery thereof. The ring belt includes an uppermost ring land and at least one oil galley contoured to extend around at least two surfaces of the uppermost ring land. The oil galley has an opening at the undercrown surface for receiving a cooling fluid therein for cooling the uppermost ring land. A skirt extends from the undercrown surface and the ring belt and has a plurality of stiffening features arranged in a truss formation. At least one of the plurality of stiffening features has an I-beam cross-section and another of the plurality of stiffening features has a negative draft angle.

A double cup-shaped piston for a disc brake including an electromechanical parking brake device. An aspect of the invention permits an improved compromise between easier operability, rationalised component logistics in piston production, reduced hydraulic volume uptake in cooperation with the wheel brake periphery, and enhanced fatigue strength under maximum collective stress, in particular for heavy-duty applications of a disc brake with an electromechanical parking brake device. The problem is solved by the presence of a piston wall, which is provided, on the one hand, to sit with a free edge on a rear plate of a friction lining, and wherein the piston, on the other hand, includes an integral dome which forms an open receptacle for an actuator arranged diametrically to the edge of the piston.

A power cylinder system for a reciprocating engine includes a piston configured to move within a cylinder of the reciprocating engine. The system also includes a groove extending circumferentially about the piston and configured to support a ring. An axially-facing surface of the groove has circumferential undulations at ambient temperatures that are configured to compensate for distortions to the groove caused by operation of the reciprocating engine.

A method for fabricating a piston with a layering device via an additive manufacturing process is provided. The method may include forming a first layer of the piston on a substrate with a layering device, forming a second layer of the piston adjacent the first layer with the layering device, and binding the first layer with the second layer. The first layer of the piston may include a first material, and the second layer of the piston may include the first material and a second material.

An accumulator piston, in particular a piston for a pressure medium accumulator of a hydraulic unit of an electronically slip-controllable vehicle brake system, includes a cylindrical piston shaft, and a piston head covering the piston shaft. The piston head includes a circumferentially closed blind-hole-shaped recess having an opening. A cross section of the recess in a region of the opening has at least one smaller dimension than a cross section in a region of a base of the recess opposite the opening. The recess forms a mechanism configured to separate particles out from the pressure medium.

Disclosed is a monoblock or cooling channel piston and a method for producing a monoblock piston for use in an internal combustion engine. A piston blank includes a circumferential collar protruding radially in the region of the piston crown is first produced and the collar is then shaped. A contact region on a top region of the piston skirts and the collar is shaped such that the outer circumferential edge thereof points at a distance to the contact region and forms a defined gap. The gap is then sealed by a closure element in order to form a closed cooling channel.