Tappet

Abstract

A tappet is proposed, for a fuel pump or for a valve timing gear, in each case of an internal combustion engine, comprising a hollow-cylindrical housing, which includes two separate portions lying in line one after the other, which are fitted together in a region of their facing inner faces and are permanently connected to one another by way of a joint. The tappet has a roller on its driving side and an abutment for a follower part on its driven side, which abutment is formed on a separate insert. The abutment is radially supported on the housing in the fitted-together region of the two portions, wherein the insert has a middle annular collar, from which on the one hand a sleeve portion protrudes in the direction of the driving side and on the other hand a dome-like attachment protrudes towards the driven side.

Claims

1. A tappet for a fuel pump or for a valve timing gear, in each case of an internal combustion engine, the tappet comprising: a hollow cylindrical housing having two separate portions which lie successively in alignment, the two portions joined together in a joined region of their facing inner faces and permanently connected together via a joint; a roller on a drive side of the cylindrical housing; an abutment configured for a follower part on an output side of the cylindrical housing, the abutment formed on a separate insert that is radially supported on the cylindrical housing in the joined region of the two portions, the insert having: a central annular collar including: a first side from which a sleeve portion protrudes in a direction of the drive side; and a second side from which a dome-like attachment protrudes towards the output side; wherein the insert is; radially supported at the joined region of the two portions by an outer ring of the annular collar; and axially supported by an outer face of the sleeve portion that rests on at least one radial indentation of a drive-side portion of the two portions; and an end face of the dome-like attachment has the abutment configured to engage the follower part.

2. The tappet as claimed in claim 1, wherein two indented, diametrically opposed flats start from a drive-side face of the housing and receive a bolt carrying the roller, and the at least one radial indentation is formed on undersides of the flats.

3. The tappet as claimed in claim 1, wherein the tappet has an installation height which corresponds to at least 1.8 times its outer diameter.

4. The tappet as claimed in claim 1, wherein a shroud of one of the two portions includes at least two annular stages, and one of the at least two annular stages with a smallest outer diameter runs in an axial portion of the joint with its outer casing joined to an inner casing portion at an inner face of the other portion.

5. The tappet as claimed in claim 4, wherein on an end side, a radially inwardly oriented stiffening collar starts from a free end of the one of the at least two annular stages with the smallest outer diameter.

6. The tappet as claimed in claim 1, wherein the two portions are joined together by welding, soldering or bonding.

7. The tappet as claimed in claim 6, wherein a welding joint or soldering joint formed by joining the two portions lies in a groove-shaped indentation on the inner faces of the two portions.

8. A tappet for a fuel pump or a valve timing gear, the tappet comprising: a hollow cylindrical housing having two separate portions which lie successively in alignment, the two portions joined together in a joined region and permanently connected together; a roller on a drive side of the cylindrical housing; an abutment arranged on an output side of the cylindrical housing and configured to engage a follower part, the abutment formed on a separate insert having: a central annular collar including: a first side from which a sleeve portion protrudes in a direction of the drive side of the cylindrical housing; and a second side from which a dome-like attachment protrudes towards the output side of the cylindrical housing; and the separate insert radially supported by the joined region of the cylindrical housing, and axially supported by a drive-side portion of the cylindrical housing.

9. The tappet of claim 8, wherein an end face of the dome-like attachment forms the abutment configured to engage the follower part.

10. A tappet for a fuel pump or a valve timing gear, the tappet comprising: a hollow cylindrical housing having two separate portions which lie successively in alignment, the two portions including an output side portion and a drive side portion that are joined together in a joined region; a roller arranged within the drive side portion; and an abutment formed on a separate insert and configured to engage a follower part, the abutment radially supported by an inner surface of the joined region and axially supported by the drive side portion.

11. The tappet of claim 10, wherein the joined region comprises facing end faces of the output side portion and the drive side portion.

12. The tappet of claim 11, wherein the output side portion comprises two annular stages including an upper annular stage and a lower annular stage, the lower annular stage: i) having a smaller outer diameter than the upper annular stage; and, ii) forming the joined region with the drive side portion.

13. The tappet of claim 11, wherein the output side portion and the drive side portion form a groove in the joined region, the groove configured to receive a weld to permanently connect the output side portion to the drive side portion.

14. The tappet of claim 10, wherein the separate insert comprises a central annular collar, the central annular collar including: a first side from which a sleeve portion protrudes in a direction of the drive side of the cylindrical housing; and a second side from which an attachment protrudes towards the output side of the cylindrical housing, an end face of the attachment has the abutment configured to engage the follower part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure is shown in the drawings. The drawings show:

(2) FIG. 1: a spatial, partly broken away view of the tappet, and

(3) FIG. 2: the above-mentioned tappet in longitudinal section.

DETAILED DESCRIPTION

(4) A tappet 1 for a high-pressure fuel pump of an internal combustion engine is shown. It comprises a two-piece, substantially hollow cylindrical housing 2.

(5) On its drive side 3, the tappet 1 has a roller 4 mounted on a bolt 27 for contact with a cam or a cam package on a crankshaft of the internal combustion engine. On its output side 5, the tappet 1 has an abutment 6 formed as part of a separate insert 29 which is supported radially and axially on the housing 2, for a follower part (pump piston).

(6) As the two figures clearly show, the housing 2 is constructed from two separate portions 7, 8 lying successively in alignment. These are joined together in the region of their facing end faces 9, 10, and connected together via a weld 11. The weld 11 lies in a groove-shaped indentation 28 axially between the portions 7, 8, and thus does not influence an outer casing of the housing 2.

(7) Two portions 7, 8 of the housing 2 consist of a thin-walled sheet steel. In contrast to metal tappets previously produced, because of the alignment of the two portions 7, 8, the tappet 1 has a length which is around twice as large as its diameter. It is therefore ideally suited but not exclusively designed for crankshaft-driven injection pumps with relatively large distances, imposed by the design, between the respective cams or eccentrics on the crankshaft and the pump piston of the injection pump to be driven.

(8) FIG. 2 shows that a shroud 12 of the output-side portion 8 consists substantially of two annular stages 13, 14. The lower annular stage 13 of smaller outer diameter runs in the axial portion of the joint 11, and on the end side has a radially inwardly oriented stiffening collar 17. Said stage lies with its outer casing 15 on an inner casing portion 16 at the inner face 9 of the other drive-side portion 7.

(9) The insert 29 mentioned above in the description of the figures has a central plate-like annular collar 18 which is radially supported in the joint region via its outer ring 19.

(10) On one side, a central sleeve portion 20 protrudes from the annular collar 18 in the direction towards the drive side 3. Its free outer face 21 is axially supported on two radial indentations 22 of the portion 7. More precisely, two flats 26 indented from the outer casing start from a drive-side face 25 of the housing 2 diametrically opposite each other. The bolt 27 carrying the roller 4 is mounted therein. The undersides of the flats 26 function as the radial indentations 22.

(11) Also, a dome-like attachment 23 protrudes from the annular collar 18 of the insert 29 through the output-side portion 8 of the housing 2. An end face 24 of the attachment 23 forms the abutment 6 for the pump piston.

LIST OF REFERENCE CHARACTERS

(12) 1) Tappet 2) Housing 3) Drive side 4) Roller 5) Output side 6) Abutment 7) Portion 8) Portion 9) Inner face 10) Inner face 11) Joint, weld 12) Shroud 13) Annular stage 14) Annular stage 15) Outer casing 16) Inner casing portion 17) Stiffening collar 18) Annular collar 19) Outer ring 20) Sleeve portion 21) Outer face 22) Radial indentation 23) Attachment 24) End face 25) Face 26) Flat 27) Bolt 28) Indentation 29) Insert