Tappet for high-pressure fuel pump, having axial fastening for pin carrying cam follower roller thereof

Abstract

The invention relates to a tappet for a high-pressure fuel pump, comprising a hollow cylindrical housing (2) which, on the drive-side front surface (3) thereof, accommodates a cam follower roller (5) running on a bolt (4), the bolt (4) being arranged on the end side in a bore (6) of the housing (2) and being axially fixed in the housing via each retaining web (7) at the front edge of the respective end side (8) thereof, the housing (2) is axially penetrated by a bridge (9) under the cam follower roller (5), an end face (11) of the bridge facing an output-side front face (10) of the housing (2) has a bearing for a pump piston, two bores (6) of the housing (2) are located in a smooth cylindrical circumferential section (12) of an outer circumferential face (13) of the housing (2), and wherein the outer circumferential face (13) of the housing (2) is located in the smooth cylindrical circumferential section (12) of the outer circumferential face (13) of the housing (2). The pin (4) protrudes only into a partial depth of each hole (6) and the retaining webs (7) located in front of the pin (4) in each case are separate pins which settle securely in the associated hole (6) in front of the end face (8) of the pin (4) and extend diagonally therethrough.

Description

Technical Field

[0001] The invention relates to a tappet, in particular for a high-pressure fuel pump, comprising a hollow cylindrical housing which, on its front drive side, accommodates a cam follower roller running on a bolt, the bolt being arranged on the end side in a hole in the housing and being fixed axially in the hole in front of its respective end face via each retaining web, wherein the housing is axially penetrated below the cam follower roller by a bridge, the end face of the bridge facing the front drive side of the housing having a support portion for a pump piston. Background Art

[0002] DE 10 2009 013 131 A1 discloses a tappet whose bolt for a cam follower roller is received in a bore in diametrically opposed flattened portions of a housing. Two retaining tabs extend orthogonally from the edge of a separately constructed bridge in the direction of the front drive side. The retaining tabs extend through the underside of the flattened portion and terminate before the end face of the bolt, securing the bolt axially. Summary of the Invention

[0003] The aim is to create a tappet with a simple axial fixation for its peg.

[0004] According to the invention, this object is achieved in that the two holes of the housing are located in a smooth cylindrical circumferential section of the outer circumference of the housing without a key surface, wherein the bolt only extends into a part of the depth of each hole, and the retaining tabs respectively located in front of the bolt are separate pins, which are firmly seated in the relevant holes in front of the end face of the bolt and extend through the holes in the diametrical direction.

[0005] This results in a simple tappet with an improved bolt fastener. The "locking" pin, located axially in front of the bolt in the bolt hole, is preferably a standardized component such as a cylindrical pin or a clamping pin / clamping sleeve. The tappet, also known as a roller tappet, is intended to be installed in particular in the pump drive of a high-pressure fuel pump of an internal combustion engine. However, the tappet can also be used in the valve train of an internal combustion engine.

[0006] It is particularly preferred that the housing be designed as a substantially circumferentially smooth cylinder on its outer circumference and at the same time have no diameter steps. In addition to the two holes for the bolts, the smooth cylindrical circumference of the housing's outer circumference is interrupted only by a connection section for the anti-rotation element, which serves as an anti-rotation element for engagement with a pump-side guide of the housing. Such a housing can be easily machined on its outer circumference in a few manufacturing steps, for example by centerless grinding.

[0007] According to a further development of the invention, the bridge is integrally connected to the housing, and the housing is produced by extrusion. Optionally, the housing can also be deep-drawn from sheet steel or as a MIM or sintered component. Alternatively, the bridge can also be a separate, individual component.

[0008] According to a specific embodiment of the present invention, the housing is thickened in sections along its inner wall, starting from its front drive side, to accommodate the two pins. In this case, the two pins engage upside down, "from above," in the upper insertion holes in the housing. If necessary, the lower insertion holes can have a smaller diameter than the upper ones, allowing the use of pins with a stepped diameter. The two insertion holes can also extend transversely / tangentially, for example, rotated 90° within the holes. Importantly, the ends of the pins do not protrude into the outer circumference of the housing.

[0009] Another advantage is the ability to use bolts that are shorter than in the prior art. In this case, the insertion depth can range from 1 / 3 to 2 / 3 of the depth of the corresponding hole. This is advantageous with regard to the quality of the tappet. A particular advantage is that no anti-rotation means for the bolt are required in either hole. Furthermore, the bolt can be provided with a wear-resistant hard material layer.

[0010] The pins can be prepared in groups of thickness according to their diameter. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 shows a perspective view of the tappet, and

[0012] Figure 2 A longitudinal section through the tappet through its pin is shown. DETAILED DESCRIPTION

[0013] The figure shows a tappet 1 for a high-pressure fuel pump. The tappet has a hollow cylindrical extruded housing 2, which is integrally connected to a bridge 9. The end face 11 of the bridge 9, which faces the driven-side front face 10 of the housing 2, serves as a support for the pump piston or as an intermediate element. Above the bridge 9, the housing 2 accommodates a cam follower roller 5, which protrudes slightly beyond the drive-side front face 3 of the housing 2. The cam follower roller 5 is mounted via a needle bearing 18 (see Figure 2 ) is supported on bolt 4.

[0014] The housing 2, which is smooth cylindrical and has no steps in diameter on its outer circumference 13, has two diametrically opposed holes 6 on its front side 3 on the drive side. The aforementioned bolt 4 is arranged in the hole 6 so that it can rotate freely on the end side, as shown in FIG. Figure 2 It is most clearly seen that the axial direction does not fully extend from the hole.

[0015] The bolt 4 is fixed axially in the two holes 6 via a retaining tab 7 in front of its respective end face 8, which retaining tab 7 is present as a separate pin. Figure 2 It can be seen in FIG that the respective pin 7 is a clamping sleeve and extends in the height direction of the tappet 1. Here, the pin 7 is placed in the respective insertion hole 14, 15 of the hole 6 via a press fit.

[0016] Depend on Figure 1 It can also be seen that the "upper" plug-in holes 14 intersect the drive-side front face 3 of the housing. The drive-side front face 3 is thickened radially inward in the form of a sheet metal in the circumferential region 16 where the holes 6 are located. The corresponding pin 7 engages via the "upper" plug-in hole 14.

[0017] at last Figure 1 The outer circumference 13 of the housing 2 is shown to have an engagement section 17 configured as a longitudinal groove for engaging an external anti-rotation member. In this case, the engagement section 17 starts from the drive side front 3 of the housing 2 and extends approximately half the height of the housing.

[0018] Reference Signs List

[0019] 1) Tappet

[0020] 2) Housing

[0021] 3) Front view of driving side

[0022] 4)bolt

[0023] 5) Cam follower roller

[0024] 6) Hole

[0025] 7) Keep the tabs and pins

[0026] 8) End side

[0027] 9) Bridge

[0028] 10) Driven side front

[0029] 11) End face

[0030] 12) Circumferential segment

[0031] 13) Outer surface

[0032] 14) Socket

[0033] 15) Socket

[0034] 16) Joint section

[0035] 17) Needle roller bearings

Claims

1. A tappet (1), in particular for a high-pressure fuel pump, comprising a hollow cylindrical housing (2) which accommodates a cam follower roller (5) running on a bolt (4) on its drive-side front side (3), the bolt (4) being arranged at its end side in a bore (6) of the housing (2) and being fixed axially in the bore via a respective retaining tab (7) in front of its respective end side (8), wherein: The housing (2) is axially passed through by a bridge piece (9) below the cam follower roller (5), and the end face (11) of the bridge piece facing the driven side front face (10) of the housing (2) has a support part for the pump piston, characterized in that the two holes (6) of the housing (2) are located in a smooth cylindrical keyless circumferential section (12) of the outer peripheral surface (13) of the housing (2), wherein the bolt (4) only extends into a partial depth of each hole (6), and the retaining tabs (7) respectively located in front of the bolt (4) are separate pins, which are firmly arranged in the relevant hole (6) in front of the end side (8) of the bolt (4) and pass through the hole in the diametrical direction.

2. The tappet according to claim 1, characterized in that Two diametrically opposed plug-in holes (14, 15) start from corresponding holes (6) in the housing (2), in which the corresponding pin (7) extends on the end side and is pressed in at least one of the plug-in holes, and the axial line of the pin (7) and the plug-in holes (14, 15) extend parallel to the axial line of the tappet (1).

3. The tappet according to claim 2, characterized in that A corresponding insertion hole (14) adjacent to the drive-side front face (3) of the housing (2) intersects the front face (3) and a corresponding pin (7) engages thereon.

4. The tappet according to claim 1 or 3, characterized in that: The circumferential region (16) of the drive-side front side (3) of the housing (2) is thickened in a plate-like manner radially inward at the opening (6).

5. The tappet according to claim 1, wherein: The pin (7) is a cylindrical pin or a clamping pin / clamping sleeve.

6. The tappet according to claim 1, wherein: The bolt (4) is freely rotatable in the hole (6) of the housing (2) and extends in the range of 1 / 3 to 2 / 3 of its depth.

7. The tappet according to claim 1, wherein: Except for the connection section (17) for the anti-rotation element and the two holes (6), the outer circumference (13) of the housing (2) is a smooth cylindrical shape without steps.

8. The tappet according to claim 1, wherein: The bridge (9) is formed integrally with the housing (2).

9. The tappet according to claim 1 or 8, characterized in that The tappet (1) is an extrusion component.

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