Tappet for a high-pressure fuel pump of a heavy-duty internal combustion engine with a lubricating oil supply for the camshaft bearings

Abstract

A plunger (1) for a high-pressure fuel pump of a heavy-duty internal combustion engine, comprising a hollow cylindrical housing (2) which has a cam roller (6) running on a bolt (5) via a bearing (4) at its upper annular end face (3), which bolt (5) sits in receptacles (7) of diametrically opposed, vertically recessed flanges (8) of the housing (2), which is axially penetrated below the flanges (8) by a separate bridge piece (9), on the upper end face (10) of which a cover plate (11) lies, on the upper surface (12) of which the flanges (8) with their lower beams (13) stand, wherein the bridge piece (9) bears against the inner shell (15) of the housing (2) at least in the circumferential region of the two flanges (8) with an edge segment (14),wherein a lower face (17) of the bridge piece (9) facing a lower ring face (16) of the housing (2) forms at least an indirect contact surface for a follower element and the bridge piece (9) is fixed in the direction of the lower ring face (16) for example by using a retaining ring (36) on the inner shell (15) of the housing (2), wherein a targeted pressurization of the bearing (4) with lubricating oil is provided on both ends and the housing (2) for this purpose is cut by a passage (18) for the lubricating oil at only one of the edge segments (14) of the bridge piece (9), which leads to a radial channel (19) formed between the bridge piece (9) and the cover plate (11), wherein the cover plate (11) has a passage (20, 21) connected to the radial channel (19) on each flat side,which exits at an axial gap (22) between an inner wall (23) of the respective flat (8) and an adjacent end face (24) of the cam roller (6), wherein either the passage (21) furthest from the passage in the cover plate (11) has a larger diameter than the passage (20) closest to the passage and the radial channel (19) is formed continuously from edge segment (14) to edge segment (14) of the bridge piece, or wherein the passage (21) furthest from the passage and the passage (20) closest to the passage in the cover plate (11) have the same diameter and the radial channel (19), which does not extend completely, widens in a wedge- or cone-like manner from the passage (20) closest to the passage to the passage (21), or wherein the passage (21) furthest from the passage in the cover plate (11) has a larger diameter than the passage (20) closest to the passage. has,and the radial channel (19), which does not extend completely, widens in a wedge- or cone-like shape from the passage near the passage (20) to the passage furthest from the passage (21).

Description

[0001] The invention relates to a plunger for a high-pressure fuel pump of a heavy-duty internal combustion engine, comprising a hollow cylindrical housing which has a cam roller running on a bolt via a bearing at its upper ring face, the bolt being seated in receptacles of diametrically opposed, vertically recessed sections of the housing, the housing being axially penetrated below the sections by a separate bridge piece, on the upper face of which a cover plate rests, on the upper surface of which the sections with their lower beams stand, the bridge piece bearing against the inner shell of the housing at least in the circumferential region of the two sections with an edge segment, a lower face of the bridge piece facing a lower ring face of the housing forming at least an indirect contact surface for a plunger follower, and the bridge piece being fixed to the inner shell of the housing in the direction of the lower ring face, for example by using a retaining ring.wherein a targeted application of lubricating oil to both ends of the bearing is provided and the housing for this purpose is cut by a passage for the lubricating oil at only one of the edge segments of the bridge piece, which leads to a radial channel formed between the bridge piece and the cover plate and wherein the cover plate has a passage connected to the radial channel on each flat side, which exits at an axial gap between an inner wall of the respective flat and an facing end face of the cam roller.

[0002] The term "heavy-duty internal combustion engine" refers to a machine used in particular to power a truck, van, light transporter, agricultural equipment, ship, mining or construction site equipment, etc.

[0003] A plunger of this type is described in document DE 20 2024 100 850 U1. A cover plate rests on its bridge section. The bridge section has a radial channel in its upper face for lubricating oil that can be supplied from one side. This channel is connected to two passages in the cover plate, which direct the lubricating oil axially upwards into the gaps between the inner walls of the flax and the adjacent end faces of the cam roller.

[0004] Document DE 20 2024 100 849 U1 describes a plunger whose bridge piece has an inner-walled radial channel for lubricating oil on both sides, each supplied by a separate passage in the housing.

[0005] WO 2020 / 078 612 A1 shows a tappet installed in a pump unit. The tappet has a solid, integrally mounted crossmember in its head area, with a half-shell for mounting the cam roller. A lubricating oil path, fed from the tappet's guide bore, runs radially through the crossmember, from which, according to... Fig. 2 a branch channel leads towards the cam roller.

[0006] DE 10 2014 219 513 A1 also shows a plunger as described above, with a solid crossbar. Two transversely opposed paths for the lubricant lead to a shell area of ​​the crossbar; their inlets are located in recesses in the outer shell of the housing.

[0007] The reference US 10 006 425 B2 teaches a tappet with a two-sided lubricating oil supply to the cam roller bearing, each diagonally through the housing and through an insert part (see Fig. 1).

[0008] Another plunger with a two-sided lubricating oil supply diagonally through the housing in the section of its one-piece connected bridge piece is shown. Fig. 2 of DE 10 2006 031 032 A1.

[0009] From DE 10 2013 215 455 A1 (see Fig. 3, Fig. 4) Another tappet emerges. On the inner walls of the flax, which carries the bolt with the cam guide roller, an axial channel is formed as a path for dripping oil. This originates from an upper ring face of the housing and runs downwards towards the bearing.

[0010] The task is to create a tappet with improved lubrication for its cam roller bearing.

[0011] According to the invention, this problem is solved by either having the passage furthest from the passage in the cover plate having a larger diameter than the passage closest to the passage and forming a continuous radial channel from edge segment to edge segment of the bridge piece, or having the passage furthest from the passage and the passage closest to the passage in the cover plate having the same diameter and having a wedge- or cone-shaped widening of the radial channel which does not extend completely from the passage closest to the passage towards the passage furthest from the passage, or having the passage furthest from the passage in the cover plate having a larger diameter than the passage closest to the passage, and having a wedge- or cone-shaped widening of the radial channel which does not extend completely from the passage closest to the passage towards the passage furthest from the passage.

[0012] Thus, the plunger is designed so that, despite having only one contact point on the housing, its bearing receives approximately the same flow rate of lubricating / cooling oil on both sides. Additional lubrication of the bearing can be achieved via oil dripping from the upper ring face of the housing.

[0013] According to one variant, the enlarged opening in the cover plate at the point furthest from the opening in the housing compensates at least largely for the pressure loss of the lubricating oil over the length of its path.

[0014] The same applies to the wedge- or cone-shaped widening of the radial channel between the cover plate and the bridge section as an alternative, which radial channel is preferably, but not exclusively, formed / embossed into the bridge section and should run radially. It is clear that the aforementioned widening of the radial channel can occur in its transverse and / or depth directions and can be combined with the varying sizes of the openings. Generally speaking, the crucial point is that the radial channel widens in the direction of the opening furthest from the opening. Thus, discontinuous widenings, steps, wave shapes, etc., are also conceivable and intended.

[0015] An area of ​​the housing's outer casing around its single opening is designed as a reservoir for the lubricating oil. This is achieved in particular by means of a recess, flattening, pocket, annular groove, or even an annular groove segment.

[0016] The bearing for the cam roller on the bolt should preferably be a plain bearing, whereby the cam guide roller is intended to run either directly or via an intermediate ring on the bolt. Alternatively, a rolling bearing such as a needle bearing is considered.

[0017] According to a further subclaim, a rising channel for the lubricating oil is applied in the inner wall of each flax, against which inner wall the cam roller contacts with its end faces. The two rising channels improve the targeted upward delivery of lubricating oil to the bearing.

[0018] The proposed cover plate is designed as a simple stamped sheet metal part, which is joined to the bridge piece. The bridge piece itself can also be made of sheet metal. However, it could also be manufactured using a stamping and extrusion process, or generally be solid.

[0019] The tappet is intended for use primarily in a high-pressure fuel pump of a heavy-duty internal combustion engine. However, it can also be used in a high-pressure fuel pump of a passenger car's internal combustion engine or similar vehicle, or in the valve train of an internal combustion engine. A pump piston or an adapter pin are particularly suitable as tappet follower elements.

[0020] Regarding the drawing: • Fig. Figure 1 shows a spatial longitudinal section through a first variant of the plunger with differently sized openings in the cover plate; • Fig. Figure 2 shows, in detail, the bridge piece of the aforementioned plunger; • Fig. Figure 3 shows, in detail, the cover plate of the aforementioned plunger; • Fig. Figure 4 shows a spatial longitudinal section through a second variant of the plunger with a wedge-shaped widening radial channel in the bridge piece; • Fig. Figure 5 shows, as a detail, the bridge piece of the latter pestle and • Fig. Figure 6 shows, in detail, the cover plate of the latter plunger.

[0021] The following is shown in the Fig. 1, Fig. 4 A plunger 1 for a high-pressure fuel pump of an internal combustion engine. The plunger 1 has a hollow cylindrical housing 2 made of sheet steel. At an upper ring face 3, the housing 2 contains a cam roller 6. This projects slightly beyond the ring face 3 and runs on a bearing 4, designed as a sliding bearing with an intermediate ring 28, on a bolt 5. The latter is received at its end in semi-shell-like receptacles 7 of diametrically opposed, inwardly offset flanges 8 of the housing 2. The flanges 8 lie axially below a closed circumferential ring 34 of the housing 2 and have lower beams 13 facing away from the upper ring face 3. These lower beams project through the housing 2 in an arcuate fashion.

[0022] A separate bridge piece 9 (sa) runs axially below the flax 8 in the housing 2. Fig. 2, Fig. 5). This has an upper and a lower face 10, 17. The face 17 of the bridge piece 9 facing a lower ring face 16 of the housing 2 has a central contact surface for a pump piston.

[0023] The bridge piece 9 has four circumferentially evenly distributed, cloverleaf-like edge segments 14, which abut the inner shell 15 of the housing 2 and between which recesses 35 are formed (sa Fig. 2, Fig. 5).

[0024] From the one in the background of the image plane Fig. 2, Fig. A single anti-rotation lug 31 projects from the edge segment 14 shown in Figure 5. This lug runs through a longitudinal slot 30 extending from the lower ring face 16 of the housing 2 and projects beyond an outer shell 26 of the housing 2. This provides a simple anti-rotation device for the bridge piece 9 relative to the plunger 1 and for the latter relative to its guide. A separate anti-rotation element is therefore unnecessary.

[0025] As from the Fig. 1, Fig. 4, which is removable, a cover plate 11 made of sheet steel (sa) lies on the upper face 10 of the bridge section 9. Fig. 3, Fig. 6) On their upper surface 12, facing away from the bridge piece 10, stand the lower beams 13 of the flax 8. This assembly is fixed in the direction of the lower ring face 16 of the housing 2 by means of a retaining ring 36 on the inner shell 15 of the housing 2.

[0026] A rotating anti-rotation lug 32 projects radially from the cover plate 11 in one piece. This lug, together with the aforementioned rotating anti-rotation lug 31 of the bridge piece 9, engages in the longitudinal slot 30 of the housing 2, without, however, protruding beyond the outer shell 26 of the housing 2.

[0027] The cover plate 11 has two kidney-shaped cutouts 33, which are aligned with the recesses 35 below in the bridge section 9. This design allows the passage of lubricating oil or air during the oscillating operation of the plunger 1.

[0028] The housing 2 has exactly one passage 18 for lubricating oil. This is in fluid communication upstream with a recess 25 on the outer shell 26 of the housing 2 (see figure). Fig. 1, Fig. 4) The lubricating oil is supplied to the recess 25 via a supply line that intersects the tappet guide (not shown).

[0029] The bridge piece 9 has a radial channel 19 in its upper face 10, extending from edge segment 14 to edge segment 14, for the lubricating oil. This channel, e.g., embossed, is axially limited by the cover plate 11 and fed by the passage 18 in the housing 2.

[0030] In the section of each flange 8 of the housing 2, the cover plate 11 has a passage 20, 21 connected to the radial channel 19. Each of these passages emerges in the direction of the upper ring face 3 through an axial gap 22 between an inner wall 23 of the respective flange 8 and an adjacent end face 24 of the cam roller 6. It can be seen that in the variant according to the Fig. 1 - 3 the passage 20 adjacent to passage 18 has a smaller diameter than the passage 21 further away from passage 18.

[0031] In the inner wall 23 of each flax 8 a rising channel 29 for the lubricating oil in the direction of the bearing 4 is formed, supplied by the respective passage 20, 21 below in the cover plate 11.

[0032] The variant according to the Fig. 4 - 6 differs from the variant according to the Fig.1 - 3 in that the radial channel 19 widens wedge-shaped from the passage near to the passage far from the passage 20, 21 in the cover plate 11, wherein the two passages 20, 21 have the same diameter and wherein the radial channel 19 does not extend completely through.

[0033] Thus, a plunger 1 is present, whose bearing 4, designed as a sliding bearing with intermediate ring 28, receives approximately the same volume flow of lubricating oil / cooling oil on both sides, despite only having a one-sided passage 18 as the transfer point for the lubricating oil. List of reference figures 1 pestle 2 cases 3 upper ring forehead 4 Storage 5 bolts 6 cam roller 7th recording 8 Flat 9 Bridge section 10 upper forehead 11 Cover plate 12 Top 13 lower beams 14 Edge segment 15 inner mantle 16 Ring forehead 17 lower forehead 18 passage 19 Radial canal 20 passage 21 Passage 22 Axial gap 23 Interior wall 24 End forehead 25° sink 26 Outer jacket 27 Inner jacket 28 Intermediate ring 29 Riser channel 30 longitudinal slots 31 Anti-rotation nose 32 Anti-rotation approach 33. Exemption 34 Circumferential ring 35 recess 36 retaining ring

Claims

A plunger (1) for a high-pressure fuel pump of a heavy-duty internal combustion engine, comprising a hollow cylindrical housing (2) which has a cam roller (6) running on a bolt (5) via a bearing (4) at its upper annular end face (3), which bolt (5) sits in receptacles (7) of diametrically opposed, vertically recessed flanges (8) of the housing (2), which is axially penetrated below the flanges (8) by a separate bridge piece (9), on the upper end face (10) of which a cover plate (11) lies, on the upper surface (12) of which the flanges (8) with their lower beams (13) stand, wherein the bridge piece (9) bears against the inner shell (15) of the housing (2) at least in the circumferential region of the two flanges (8) with an edge segment (14),wherein a lower face (17) of the bridge piece (9) facing a lower ring face (16) of the housing (2) forms at least an indirect contact surface for a follower tappet member and the bridge piece (9) is fixed in the direction of the lower ring face (16) for example by using a retaining ring (36) on the inner shell (15) of the housing (2), wherein a targeted pressurization of the bearing (4) with lubricating oil is provided on both ends and the housing (2) for this purpose is cut by a passage (18) for the lubricating oil at only one of the edge segments (14) of the bridge piece (9), which leads to a radial channel (19) formed between the bridge piece (9) and the cover plate (11), wherein the cover plate (11) has a passage (20, 21) connected to the radial channel (19) on each flat side,which exits at an axial gap (22) between an inner wall (23) of the respective flat (8) and an adjacent end face (24) of the cam roller (6), wherein either the passage (21) furthest from the passage in the cover plate (11) has a larger diameter than the passage (20) closest to the passage and the radial channel (19) is formed continuously from edge segment (14) to edge segment (14) of the bridge piece, or wherein the passage (21) furthest from the passage and the passage (20) closest to the passage in the cover plate (11) have the same diameter and the radial channel (19), which does not extend completely, widens in a wedge- or cone-like manner from the passage (20) closest to the passage to the passage (21), or wherein the passage (21) furthest from the passage in the cover plate (11) has a larger diameter than the passage (20) closest to the passage. has,and the radial channel (19), which does not extend completely, widens in a wedge- or cone-like shape from the passage near the passage (20) to the passage furthest from the passage (21). Plunger according to claim 1, wherein one passage (18) through the housing (2) originates from a circumferential segment-like recess (25) in the outer shell (26) of the housing (2). Plunger according to claim 1, wherein the radial channel (19) between the bridge piece (9) and the cover plate (11) is formed as a molding / indentation in the upper face (10) of the bridge piece (9) and runs between its adjacent edge segments (14). Tappet according to claim 1, wherein the bearing (4) is a sliding bearing and the cam roller (6) with its inner sleeve (27) runs either directly or via an intermediate ring (28) on the bolt (5). Piston according to claim 1, wherein a rising channel (29) for the lubricating oil in the direction of the bearing (4) is formed in the inner wall (23) of each flax (8).

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