A guide ring for a pump element of a hydraulic unit of a vehicle brake system is configured to guide a pump piston in a pump housing when the pump piston is displaced along the axis thereof in the pump housing. On the inner side of the guide ring facing the pump piston, the guide ring includes a first step that has a first inner diameter and a second inner diameter.

A piston for an internal combustion engine includes a cylindrical piston body defining a longitudinal axis and having a top end and an outer cylindrical surface. A first piston ring groove is formed in the outer cylindrical surface and includes a groove root, an upper surface and a lower surface. The groove root has a variable depth about a circumference of the cylindrical piston body.

A piston assembly for an internal combustion engine includes a cylinder bore and a piston having a plurality of ring grooves, and a ring positioned within a ring groove. The ring includes a cross-section having a lower surface and an outer radial surface that form a scraping corner, an inner radial surface, and an upper surface. The upper surface and the lower surface are generally parallel with one another, and both upper and lower surfaces form a positive first angle with respect to a radial axis, and the outer radial surface forms a second positive angle with respect to a central axis. A constant twist occurs in the ring about a rotational center of the cross-section, the constant twist occurring at each cross-sectional location of the ring about the circumference of the ring and between adjacent free ends of the ring.

A piston assembly for an internal combustion engine includes a cylinder bore and a piston having a plurality of ring grooves, and a ring positioned within a ring groove. The ring includes a cross-section having a lower surface and an outer radial surface that form a scraping corner, an inner radial surface, and an upper surface. The upper surface and the lower surface are generally parallel with one another, and both upper and lower surfaces form a positive first angle with respect to a radial axis, and the outer radial surface forms a second positive angle with respect to a central axis. A constant twist occurs in the ring about a rotational center of the cross-section, the constant twist occurring at each cross-sectional location of the ring about the circumference of the ring and between adjacent free ends of the ring.

An inlet port provides a fluid entrance to a body. A chamber has an inner surface. An outlet port is in fluid communication with the chamber and provides a fluid exit from the body. The piston is moveable within the chamber between a first set position, in which the inlet port is not in fluid communication with the outlet port, and a second open position, in which the inlet port is in fluid communication with the outlet port through the chamber. A seal guard is slidably disposed within the chamber. The seal guard is moveable between a first seal-guard position and a second seal-guard position in which the seal guard shields the seal. The seal guard is in the first seal-guard position when the piston is in its first set position and in the second seal-guard position when the piston is in its second open position.

A three-piece oil ring for an internal combustion engine may include an expanding element defining at least a first side and a second side opposite the first side. A first upper annular segment may be associated with the first side of the expanding element. A second lower annular segment may be associated with the second side of the expanding element. The first annular segment and the second annular segment may each include a first internal side surface and a second external side surface. A metallic tungsten matrix coating may be disposed on at least one of the expanding element, the first annular segment and the second annular segment via chemical vapor deposition. The coating may contain a tungsten nanocarbide that may include at least one of WC, W2C, W3C and W12C. The coating may include a thickness between 5 μm and 150 μm and a hardness between 1000HV and 3500HV.

A three-piece oil ring for an internal combustion engine may include an expanding element defining at least a first side and a second side opposite the first side. A first upper annular segment may be associated with the first side of the expanding element. A second lower annular segment may be associated with the second side of the expanding element. The first annular segment and the second annular segment may each include a first internal side surface and a second external side surface. A metallic tungsten matrix coating may be disposed on at least one of the expanding element, the first annular segment and the second annular segment via chemical vapor deposition. The coating may contain a tungsten nanocarbide that may include at least one of WC, W2C, W3C and W12C. The coating may include a thickness between 5 μm and 150 μm and a hardness between 1000HV and 3500HV.

The invention relates to a medical drug delivery apparatus which comprises a cartridge (1) being closed at one end by a membrane (12) and at the opposite end by a movable piston (15). A piston rod foot (1) is provided for transferring the pressure from the piston rod (20) of the drug delivery apparatus and onto the piston (15). The piston rod foot (1) comprises a center part (2) abutting the piston rod (20) and an outer part (3) which center part (2) and outer part (3) are coupled together such that the two (2, 3) can be moved relative to one another, yet remain coupled to each other, when a force above a certain threshold limit is applied to the outer part (3).

The invention relates to a medical drug delivery apparatus which comprises a cartridge (1) being closed at one end by a membrane (12) and at the opposite end by a movable piston (15). A piston rod foot (1) is provided for transferring the pressure from the piston rod (20) of the drug delivery apparatus and onto the piston (15). The piston rod foot (1) comprises a center part (2) abutting the piston rod (20) and an outer part (3) which center part (2) and outer part (3) are coupled together such that the two (2, 3) can be moved relative to one another, yet remain coupled to each other, when a force above a certain threshold limit is applied to the outer part (3).

A piston ring set for internal combustion (IC) engine is provided. The IC engine includes a cylinder having a liner and a finish on the liner. A piston having a crown and a set of grooves is disposed in the cylinder. A set of piston rings is disposed in the set of grooves. The piston rings are disposed in order from closest to the crown and include at least a first compression ring having free ends defining a first end gap, a second compression ring having free ends defining a second end gap. A nominal value of the first end gap of the first compression ring is greater than a nominal value of the second end gap of the second compression ring.