Tappet for high-pressure fuel pump of heavy-duty internal combustion engine

Abstract

The invention relates to a tappet for a high-pressure fuel pump of a heavy-duty internal combustion engine, comprising a hollow cylindrical housing which accommodates a cam roller at the upper end thereof, which cam roller runs on a bolt via a sliding bearing lubricated by pressure oil, which bolt is arranged in a planar portion of the housing, a bridging part integrally connected with the inner circumferential face penetrates through the shell and extends below the cam roller, an independent bottom gasket is arranged on the lower surface of the bridging part, a concave notch located in the center is formed in the lower end face of the bottom gasket, and the bottom of the notch is used as a bearing face of the end face of a pump piston. The wall of the recess serves as a direct holding means for the circumferential section of the pump piston, the lower end face of the bottom gasket has an annular bearing at the edge thereof for supporting the pump piston spring, the upper end face of the bottom gasket rests on the lower surface of the bridge, and a pressure oil path supplied by a radial channel in the housing is provided in the upper end face. And the pressure oil path leads to an axial through hole which is formed in the bridging part and is directly opened at the inner end face of the plane part.

Description

Technical Field

[0001] This invention relates to a tappet for a high-pressure fuel pump in a heavy-duty internal combustion engine. The tappet has a hollow cylindrical housing, the upper end of which houses a cam roller. The cam roller rotates on a bolt via a sliding bearing lubricated by pressure oil. The bolt is disposed in a planar portion of the housing. The housing has a bridging portion connected to an inner circumferential surface. The bridging portion extends through the cam roller. In the region of the bridging portion, there is a pressure oil path supplied by a radial channel in the housing. This pressure oil path connects to an axial through hole formed directly at the inner end face of the planar portion. Background Technology

[0002] "Heavy-duty internal combustion engine" refers to engines, especially those used to power equipment such as trucks, transport vehicles, light transport vehicles, agricultural equipment, ships, mining or construction site equipment.

[0003] DE202024100850U1 discloses a tappet whose cam roller has a sliding bearing lubricated by pressurized oil. The tappet has a bridging portion separately assembled with a housing, the upper surface of which is provided with a cover plate. An oil passage for supplying pressurized oil to the sliding bearing of the cam roller is provided between the cover plate and the bridging portion. Summary of the Invention

[0004] The purpose of this invention is to design a tappet that has a simple structure, can withstand high loads in heavy-duty applications, and has improved functionality.

[0005] According to the present invention, this objective is achieved by the novel feature of claim 1. Accordingly, the bridging portion is integrally connected to the inner circumferential surface of the housing, and a separate bottom gasket is provided on the lower surface of the bridging portion. The bottom gasket includes a recessed central notch on its lower end face. The bottom of the notch serves as a support surface for the pump piston end face, and the wall of the notch serves as a direct holding device for the circumferential section of the pump piston. The lower end face of the bottom gasket is provided with an annular support portion extending at its edge for supporting the pump piston spring. The upper end face of the bottom gasket abuts against the lower surface of the bridging portion, and a pressure oil passage supplied by a radial channel in the housing is provided in the upper end face. This pressure oil passage communicates with an axial through hole formed directly on the inner end face of the planar portion in the bridging portion.

[0006] Therefore, it is worth emphasizing that the bottom gasket abutting the integrally connected bridging portion has multiple functions, and this bottom gasket is preferably a solid structure. On one hand, an oil passage for delivering pressurized oil to an axial through-hole in the bridging portion is formed within the bottom gasket, and this oil passage is defined and sealed by the bridging portion on its axial opposite side. On the other hand, an annular support and guide structure for the pump piston spring end face are provided in the lower end face of the bottom gasket. Furthermore, the lower end face of the bottom gasket, through a provided notch, provides a simple method for engaging, holding, and guiding the pump piston of the high-pressure fuel pump, wherein the pump piston has a certain angular movement space in the engaged state. A separate spring seat connected to the pump piston spring is not required.

[0007] According to an embodiment of the present invention, the pressure oil passage in the upper end face of the bottom gasket can be described as comprising two concentrically arranged annular grooves connected by at least one radial groove. The outer annular groove is in fluid communication with a radial channel in the housing. The inner annular groove is orthogonally connected to an axial through hole in the bridging portion. Alternatively, the oil passage can also be provided in the lower surface of the bridging portion and defined by the bottom gasket.

[0008] According to another embodiment of the invention, the bottom gasket has at least one sealing ring on its outer circumferential surface, and abuts against the inner circumferential surface of the housing through this sealing ring, thereby ensuring good leak-proof performance of the oil passage at this location. Alternatively, the sealing ring can also be installed on the inner circumferential surface of the housing. The connection between the bottom gasket and the housing is preferably designed such that, for example, during the transport of the tappet, the bottom gasket can be fixed inside the housing. Anti-rotation orientation of the bottom gasket is not required, which simplifies its assembly process.

[0009] Another dependent claim relates to a practical design for a recess in the bottom gasket for holding / guiding the pump piston. This recess can be designed as a keyhole-shaped channel, including an eccentric insertion opening and a centrally located, intersecting, fixing opening for securing the pump piston. Clearly, in this case, the pump piston can be secured, for example, by providing an annular groove in the insertion area, and by means of this annular groove, the pump piston can be ultimately engaged into the fixing opening. Alternatively, securing it can be achieved using a retaining ring or similar method.

[0010] The pump piston spring can be placed in the recessed annular step of the annular support of the bottom gasket on the end side, without the need for a separate spring seat, thus achieving good guidance.

[0011] The cam rollers run with a very small clearance in front of the inner end face of the planar portion via a sliding bearing (in which an intermediate ring may also be provided). A rising oil passage is formed in the inner end face, through which pressurized oil flowing from the axial through-hole in the bridging portion is guided to the sliding bearing. The axial through-hole can extend along the inner wall of the planar portion all the way to the upper end of the housing.

[0012] The push rod can be manufactured by extrusion molding or sheet metal stamping and bending processes. Attached Figure Description

[0013] The attached figures include:

[0014] Figure 1 This is a longitudinal sectional view of the tappet;

[0015] Figure 2 for Figure 1 Longitudinal sectional view of the middle tappet after rotating 90°;

[0016] Figure 3 A perspective view of the housing of the tappet with a partial cross-section, the tappet including the installed bottom gasket and the pump piston with pump piston spring;

[0017] Figure 4 A three-dimensional top view of a single bottom pad;

[0018] Figure 5 A three-dimensional bottom view of a single bottom pad. Detailed Implementation

[0019] Figure 1 and Figure 2 The tappet 1 in a high-pressure fuel pump specifically designed for heavy-duty internal combustion engines is shown.

[0020] The push rod 1 has a hollow cylindrical, extruded housing 2. A cam roller 4 is mounted at the upper end 3 of the housing 2, slightly extending beyond the end face. The cam roller 4 runs on a bolt 6 via a sliding bearing 5. The two ends of the bolt 6 are positioned in receiving portions 33 of two radially opposing planar portions 8 of the housing 2 (e.g., ...). Figure 3 As shown in the figure.

[0021] Below the axis of the cam roller 4, an integrally connected bridging portion 10 extends from the inner surface 9 of the housing 2, and the bridging portion 10 has a through hole in the middle (e.g., Figure 3 (As shown). A separate solid bottom gasket 12 is provided on the lower surface 11 of the bridging portion 10. The bottom gasket 12 has a recessed central notch 14 at its lower end face 13 (see also). Figure 5 The bottom 15 of the recess 14 is used to support the end face 16 of the pump piston 17. The wall 18 of the recess 14 is designed as a direct holding device for the circumferential section 19 of the pump piston 17 (see further description below).

[0022] like Figure 1 and Figure 2As shown, the lower end face 13 of the bottom gasket 12 has an annular support portion 21 extending at its edge 20 in the shape of a sunken annular step for supporting the pump piston spring 22. A sealing ring 32 is provided at the edge 20 of the bottom gasket 12, and the bottom gasket 12 abuts against the inner circumferential surface 9 of the housing 2 through the sealing ring 32.

[0023] like Figure 4 As shown, an oil passage 25 is provided in the upper end face 23 of the bottom gasket 12. This oil passage 25 is supplied with oil by the radial channel 24 in the housing 2, thereby delivering pressurized oil to the sliding bearing 5. The oil passage 25 includes an annular groove 28 located in the edge region between the outer peripheral surface 29 and the upper end face 23 of the bottom gasket 12. Two opposing radial grooves 30 branch inward from the annular groove 28, which are other components of the oil passage. The radial grooves 30 lead to another annular groove 31, which is also a component of the oil passage. The axial through hole 27 in the bridging portion 10 is located above the annular groove 31.

[0024] The delivery of pressurized oil from the axial through-hole 27 to the sliding bearing 5 is achieved through the axial rising oil passage 7 in the inner end face 26 of the flat part 8.

[0025] Figure 5 The structure of the wall portion 18 of the recess 14 in the bottom gasket 12 for securing the pump piston 17 is shown. The wall portion 18 is designed as a keyhole-shaped channel, including an off-center insertion opening 34 for the pump piston 17, which intersects with a centrally located securing opening 35 for the pump piston 17. Figure 1 and Figure 2 The final installed and fixed state of the pump piston 17 is shown. During the cam lift, the end face 16 of the pump piston 17 abuts against the bottom 15 of the recess 14 and is able to move slightly within it.

[0026] List of reference numerals

[0027] 1. Tappet

[0028] 2. Shell

[0029] 3. Top

[0030] 4 Cam Rollers

[0031] 5. Sliding bearings

[0032] 6 bolts

[0033] 7 Axial rising oil passage

[0034] 8. Planar section

[0035] 9. Inner circumferential surface

[0036] 10 Bridging section

[0037] 11 Lower surface

[0038] 12 Bottom gaskets

[0039] 13 Lower end face

[0040] 14 Notch

[0041] 15 Bottom

[0042] 16 End face

[0043] 17 Pump piston

[0044] 18. Wall section

[0045] 19th week section

[0046] 20 Edge

[0047] 21 Annular support section

[0048] 22 Pump piston spring

[0049] 23. Top surface

[0050] 24 Radial channels

[0051] 25. Oil circuit

[0052] 26 Inner end face

[0053] 27 Axial through hole

[0054] 28 Annular groove

[0055] 29. Outer circumference

[0056] 30 radial grooves

[0057] 31 Annular groove

[0058] 32 Sealing ring

[0059] 33. Reception Department

[0060] 34 Insert opening

[0061] 35 Fixed opening

Claims

1. A tappet (1) for a high-pressure fuel pump in a heavy-duty internal combustion engine, said tappet (1) comprising a hollow cylindrical housing (2), wherein, The upper end (3) of the housing (2) accommodates a cam roller (4), which operates on a bolt (6) via a sliding bearing (5) lubricated by pressure oil. The bolt (6) is located in the flat portion (8) of the housing (2). The housing (2) has a bridging portion (10) integrally connected to the inner circumferential surface (9) of the housing (2). The bridging portion extends through the cam roller (4) below. A separate bottom gasket (12) is provided on the lower surface (11) of the bridging portion (10). The lower end face (13) of the bottom gasket (12) includes a recessed central notch (14). The bottom (15) of the notch (14) serves as a support for the end face (16) of the pump piston (17). The wall portion (18) of the recess (14) serves as a direct holding device for the circumferential section (19) of the pump piston (17), wherein the lower end face (13) of the bottom gasket (12) has an annular support portion (21) extending at the edge (20) of the lower end face for supporting the pump piston spring (22), wherein the upper end face (23) of the bottom gasket (12) abuts against the lower surface (11) of the bridging portion (10), and the upper end face (23) is provided with a pressure oil passage (25) supplied by a radial channel (24) in the housing (2), the pressure oil passage (25) communicating with an axial through hole (27) formed directly at the inner end face (26) of the planar portion (8) in the bridging portion (10).

2. The tappet according to claim 1, wherein, The pressure oil passage (25) in the upper end face (23) of the bottom gasket (12) includes an annular groove (28), which is located in the edge region between the outer peripheral surface (29) of the bottom gasket (12) and the upper end face (23) of the bottom gasket. The annular groove is connected to the radial channel (24) in the housing (2). At least one radial groove (30) is branched from the annular groove (28). The radial groove (30) communicates with another annular groove (31) in the upper end face (23) that is connected to the axial through hole (27) in the bridging part (10).

3. The tappet according to claim 1, wherein, The bottom gasket (12) is placed within the inner circumferential surface (9) of the housing (2) by at least one sealing ring (32) fitted at the outer circumferential surface (29).

4. The tappet according to claim 1, wherein, The wall (18) of the recess (14) in the bottom gasket (12) for fixing the pump piston (17) is designed as a keyhole-shaped channel.

5. The tappet according to claim 1, wherein, The annular support (21) for the pump piston spring (22) in the lower end face (13) of the bottom gasket (12) is a sunken annular step.

6. The tappet according to claim 1, wherein, Each planar portion (8) has an axial upward path (33) in its inner end face (26) for guiding the pressure oil to the sliding bearing (5).

7. The tappet according to claim 1, wherein, The housing (2) is an extruded part or a metal sheet stamped part.

8. The tappet according to claim 1 or 3, wherein, The bottom pad (12) is axially fixed and placed in the inner circumferential surface (9) of the housing (2) without rotational orientation restriction.

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