A follower mechanism movable within a bore, the mechanism including an outer cup with a substantially cylindrical side wall and a first annular lip portion disposed at a first end of the side wall, an inner cup including a side wall portion defining a pair of shaft apertures and a ledge that is transverse to a longitudinal center axis of the follower mechanism, the inner cup being disposed in the outer cup so that the first annular lip portion of the outer cup abuts a top surface of the side wall portion of the inner cup, a pallet having an outer perimeter, at least a portion of the outer perimeter being adjacent the ledge of the inner cup, a shaft having a first end and a second end disposed in the shaft apertures, and a roller follower rotatably received on the shaft.

A pump includes a cylinder having a working chamber which contains a fluid. A drive system including at least two linear motors which are connected electrically and/or mechanically in parallel moves a piston in the working chamber to bound the working chamber in the cylinder and to pressurize the fluid in the working chamber. A piston rod is connected to the piston and bundles a force applied by the drive system.

The disclosure proposes a tappet with a housing which is composed of a drive-side and an output-side section. The drive-side section, at its outer end, has a roller and the output-side section, at its outer end, has a contact area for a follower part. The separate sections are axially spaced apart from one another and are connected to one another by a central rod piece.

In order to provide a piston device that is of simple construction and provides optimised sealing, it is proposed that the piston device should include the following: a housing that includes a piston receptacle; a piston that is arranged to be linearly displaceable in the piston receptacle; a main gasket element that separates a first medium space from a second medium space, and a supplementary gasket element, different from the main gasket element, for sealing in a region between the piston and the piston receptacle.

A fuel injection pump pressurizes and injects fuel. A cam rotates about a rotational axis of the cam. A housing includes a cam chamber that houses the cam and a sliding chamber communicated to the cam chamber. A roller rotates while being in contact with a surface of the cam. A shoe reciprocates in the sliding chamber by rotation of the cam and is in contact with and slides on a surface of the roller. A plunger reciprocates with the shoe. A cylinder houses the plunger and includes a pump chamber to pressurize and feed the fuel by reciprocation of the plunger. A deformed section is a groove or a protrusion which extends in a direction of a rotational axis of the cam, on a part of a surface of the cam, and has a shape different from a cam profile of the cam.

A pump includes a pump body having an admission valve movable therein to alternately block and unblock a valve seat to connect a low pressure space to a pumping chamber. A control valve is positioned fluidly between a control chamber and the low pressure space, and moves between a closed position where the control chamber receives high pressure for hydraulically actuating the admission valve, and an open position where the control chamber is connected to the low pressure space to enable closing of the admission valve. The pilot actuation of the admission valve produces a greater travel distance and efficiency than what might be available with certain other actuating mechanisms.

A tappet assembly for use in translating force between a camshaft lobe and a fuel pump assembly via reciprocal movement within a tappet cylinder having a guide slot. The tappet assembly comprises a tappet body having a shelf and defining a pair of apertures, and a follower assembly. The follower assembly has a shaft, a first bearing and a second bearing, each supported on the shaft for engaging the camshaft lobe. A beam is further supported on the shaft between the first and second bearings and has a platform for engaging the fuel pump assembly. The shaft is disposed in the pair of apertures of the tappet body and the beam is arranged in the tappet body and engaged with the shelf.

A piston pump as a high-pressure fuel pump of a common rail system includes: a pump cylinder; a pump piston moveably mounted in a recess of the pump cylinder, the pump piston being moveable up and down in the recess; and a leakage groove arranged in the pump cylinder in a region of the recess, the leakage groove being coupled with a leakage line configured to discharge a fuel leakage. Between the pump cylinder and the pump piston a different size pairing clearance is formed in first and second portions of the pump cylinder.

The invention relates to a roller tappet (1) for a piston pump, in particular for a high-pressure fuel pump, for supporting a pump piston (2) which can move in a reciprocating motion on a cam (3) or eccentric of a drive shaft (4), comprising a tappet body (5) with an end-side recess (6) and two radial bores (7) which lie diametrically opposite one another at the recess (6) and receive a pin (8), on which a roller (10) is rotatably mounted directly or indirectly via a bearing bush (9), wherein at least one radially or obliquely running feed bore (12) is configured in the tappet body (5) in order to supply a lubricating medium to a radial bearing gap (11) which is configured between the roller (10) and the pin (8) or between the roller (10) and the bearing bush (9), which feed bore (12) opens into the recess (6) in the region of an axial bearing gap (13) between the roller (10) and the tappet body (5). According to the invention, the feed bore (12) is connected to an arcuately running lubricating duct (14) which is configured in a surface (15) of the tappet body (5), which surface (15) delimits the axial bearing gap (13). Furthermore, the invention relates to a piston pump comprising a roller tappet (1) of said type.

A pump unit for feeding fuel, in particular diesel fuel, to an internal-combustion engine; the pump unit comprising a head (2) inside which a cylinder (3) is formed along an axis; a pumping piston (4) housed inside the cylinder and comprising a head portion (24) inside the cylinder and an opposite foot portion (23) projecting outside the cylinder; wherein the piston is slidable inside the cylinder in a reciprocating manner between a first position and a second position where the foot projects from the cylinder by a greater or smaller amount respectively; and wherein the outer surface of the piston comprises a portion (16) with a surface finish so as to have less friction and a greater lubricant-retaining capacity than the remainder of the outer surface of the piston; the portion extending along the axis between the head of the piston and a first intermediate point (17) in the first position of the piston, the first intermediate point being inside the cylinder.