Tappet

Abstract

A plunger (1) for a high-pressure fuel pump is proposed, having a housing (2) which is similar to a tube and in the drive-side annular face (3) of which two flats (5) lie diametrically opposite one another which are indented from an outer shell (4) of the housing (2) and in which a pin (7) is mounted which supports a roller, wherein an inner shell (8) of the housing (2) is penetrated axially below the roller by a separate bridge piece (9), the lower face (10) of which acts as a rest for a pump piston in the case of an output-side annular face (11) of the housing (2), wherein the bridge piece (9) is fixed against rotation about an axial line of the housing (2) and is configured as a thick-walled longitudinal beam, with the result that an area (13) in the manner of a cylindrical segment remains between the longitudinal walls (12) of said longitudinal beam and the inner shell (8) of the housing (2), wherein, in order to fix the bridge piece (9) against rotation about the axial line of the housing (2), in the circumferential section of the inner shell (8) of the housing (2), in a first transverse wall (14) of the bridge piece (9), at least one projection (15) protrudes from one of the components (8, 14), which projection (15) is seated in a respectively complementary recess (16) of the respective other one of the components (14, 8).

Claims

1. A tappet, comprising a tube-shaped housing defining an axis and comprising two flats which extend inward from the housing near a drive-side annular face of the housing and lie diametrically opposite each other, a pin for carrying a roller, the pin being mounted in said flats, a bridge member engaging the housing axially below the pin, a lower face of said bridge member configured to support a tappet follower member near a driven-side annular face of said housing, and said bridge member being fixed against rotation about the axis of the housing, wherein the bridge member is configured as a beam such that a pair of cylindrical segment-shaped spaces remain between longitudinal walls of the bridge member and the inner shell of the housing, wherein to fix the bridge member against rotation about the axial line of the housing, in a circumferential section of the inner shell of the housing, at least one projection protrudes from one of the inner shell or a first transverse wall of the bridge member, said projection is seated in a respective complementary recess of the respective other one of the first transverse wall or the inner shell, wherein undersides of the flats fix the bridge member in a direction of the drive-side annular face of the housing, and wherein at least one extension protrudes radially inwards from an upper annular wall of the housing near each of the flats, and said extensions limit an axial displacement of the pin.

2. The tappet according to claim 1, wherein for a further fixing of the bridge member against rotation about the axial line of the housing, the bridge member comprises in a region of a second transverse wall a lug that extends through a clearance of the housing.

3. The tappet according to claim 2, wherein for rotationally securing the tappet relative to a surrounding structure, the lug protrudes beyond the outer shell of the housing.

4. The tappet according to claim 1, wherein the at least one projection is in the housing, and wherein the first transverse wall of the bridge member comprises either a) said complementary recess located approximately in a central position, or b) two complementary recesses located near edge regions of the bridge member to the longitudinal walls.

5. The tappet according to claim 1, wherein the at least one projection is in the housing, and configured either a) as an embossing/material stamping starting from the outer shell of the housing, b) as rudimentary stampings on the inner shell of the housing, or c) as weld or solder spots on the inner shell of the housing.

6. The tappet according to claim 1, wherein the first transverse wall of the bridge member is approximately flat except for said projection or said recess.

7. The tappet according to claim 1, wherein the bridge member is fixed in a direction of the driven-side annular face of the housing through support on a securing ring that is fixed on the inner shell of the housing.

8. The tappet according to claim 1, wherein the bridge member is retained within the housing with a slight axial and radial lash.

9. A tappet for a pump or a compressor, comprising a tube-like housing longitudinally defining an axis, including: two diametrically opposed flats indented from the housing near a drive-side annular face of the housing, an inner surface, and at least one radial projection located above the flats; a bridge member mounted on a respective underside of each flat and having a generally rectangular cross-section, the bridge member including: a lower face configured to support a tappet follower member, a first transverse wall at a first end of the bridge member, the first transverse wall engaging the inner surface of the housing, a lug extending from a second transverse wall at a second end of the bridge member, the lug penetrating the inner surface of the housing; at least one projection protruding from the housing or the bridge member; at least one complementary recess formed in the housing or the bridge member for receiving the at least one projection and fixing the bridge member against rotation about the axis; and a pin mounted in receptions of each flat, the receptions being located on an opposite face of the flats from the undersides.

10. The tappet according to claim 9, wherein the bridge member, when assembled in the housing, has a consistent cross-section along an inner diameter of the housing.

11. The tapped according to claim 9, the bridge member including a lower face that is substantially flat, the lower face being situated near a driven side of the housing.

12. A tappet, comprising a tube-shaped housing defining an axis and comprising two flats which are indented from an outer shell of the housing near a drive-side annular face of the housing and lie diametrically opposite each other, a pin for carrying a roller, the pin being mounted in said flats, a bridge member engaging an inner shell of the housing axially below the pin, a lower face of said bridge member configured to support a tappet follower member near a driven-side annular face of said housing, and said bridge member being fixed against rotation about the axis of the housing, wherein the bridge member is configured as a beam such that a pair of cylindrical segment-shaped spaces remain between longitudinal walls of the bridge member and the inner shell of the housing, wherein to fix the bridge member against rotation about the axial line of the housing, in a circumferential section of the inner shell of the housing, at least one projection protrudes from one of the inner shell or the first transverse wall, said projection is seated in a respective complementary recess of the respective other one of the first transverse wall or the inner shell, and wherein at least one extension protrudes radially inwards from an upper annular wall of the housing near each of the flats, and said extensions limit an axial displacement of the pin.

13. The tappet according to claim 12, wherein for a further fixing of the bridge member against rotation about the axial line of the housing, the bridge member comprises in a region of a second transverse wall a lug that extends through a clearance of the housing.

14. The tappet according to claim 13, wherein for rotationally securing the tappet relative to a surrounding structure, the lug protrudes beyond the outer shell of the housing.

15. The tappet according to claim 12, wherein the at least one projection is in the housing, and wherein the first transverse wall of the bridge member comprises either a) said complementary recess located approximately in a central position, or b) two complementary recesses located near edge regions of the bridge member to the longitudinal walls.

16. The tappet according to claim 12, wherein the at least one projection is in the housing, and configured either a) as an embossing/material stamping starting from the outer shell of the housing, b) as rudimentary stampings on the inner shell of the housing, or c) as weld or solder spots on the inner shell of the housing.

17. The tappet according to claim 12, wherein the bridge member is fixed in a direction of the driven-side annular face of the housing through support on a securing ring that is fixed on the inner shell of the housing.

18. The tappet according to claim 12, wherein the bridge member is retained within the housing with a slight axial and radial lash.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described more closely with reference to the appended drawing.

(2) FIG. 1 shows a three dimensional view of the tappet seen from below, showing a first variation of a rotational fixing of the bride member;

(3) FIG. 2 shows a cross-section through the tappet according to FIG. 1, at the level of the bridge member;

(4) FIG. 3 shows the tappet according to FIG. 1, showing an alternative rotational fixing;

(5) FIG. 4 shows the cross-section corresponding to FIG. 3;

(6) FIG. 5 shows a longitudinal section through the tappet according to FIG. 3 in an upright position, taken in longitudinal direction through the bridge member, and

(7) FIG. 6 shows a view similar to FIG. 3, with a securing ring serving as an axial fixing for the bridge member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(8) FIGS. 1 and 2 disclose a tappet 1 for a high pressure fuel pump. This possesses a tube-like housing 2 made out of sheet steel. Near a drive-side annular face 3 of the housing 2 are arranged two diametrically opposing flats 5 that are indented from an outer shell 4 of the housing 2. A pin 7 carrying, through a needle roller bearing a roller, not shown, is received in receptions 25 of the flats 5 (see also FIG. 5).

(9) An inner shell 8 of the housing 2 is penetrated axially below the roller by a bridge member 9 that is configured as a longitudinal beam. In this way a cylindrical segment-like space 13 remains between each of the longitudinal walls 12 of the bridge member 9 and the inner shell 8 of the housing 2 for enabling a relatively unobstructed passage of the lubricant.

(10) A lower face 10 of the bridge member 9 situated near a driven-side annular face 11 of the housing 2 functions as a support for a piston pump that constitutes the tappet follower member.

(11) The bridge member 9 is fixed against rotation about an axial line of the housing 2. For this purpose, two integrally formed projections 15 protrude from the inner shell 8 of the housing 4 near a first, almost flat transverse wall 14 of the bridge member 9 and are situated in complementary recesses 16 in the edge region 20 of the transverse wall 14. The projections 15 are configured as material indentations starting from the outer shell 4 of the housing 2.

(12) It can be seen further that, in the region of its second transverse wall 17, the bridge member 9 possesses a lug 18 that extends through a clearance 19 of the housing 2. Through this integrally connected lug 18, the tappet is endowed with a rotational securing relative to its guide. The lug 18 serves at the same time as a further rotational fixing of the bridge member 9 about the axial line of the housing 2.

(13) FIGS. 3 to 5 disclose an alternative retention for the bridge member 9 in peripheral direction. In this case, the first transverse wall 14 of the bridge member 9 comprises only one central recess 16 in which a respective projection 15 of the housing 2 is seated.

(14) The respective recess 15 may comprise a step-like shoulder so that the bridge member 9 is prevented from falling out of the tappet. As disclosed in FIG. 6 in this context, a securing ring 22 is arranged on the inner shell 8 of the housing 2, and the bridge member 9 is retained on this securing ring at its transverse walls 14, 17.

(15) In the direction of the drive-side annular face 3 of the housing 2, the bridge member 9 bears against undersides 21 of the indented flats 5.

(16) Finally, as disclosed in FIGS. 1, 3 and 5, an extension 24 extends integrally, radially inwards from an upper annular wall 23 of the housing 2 near each flat 5 so that the two extensions 24 serve to limit the displacement of the pin 7 in axial direction. The extension 24 is made as a simple material incision.

LIST OF REFERENCE NUMERALS

(17) 1 Tappet 2 Housing 3 Drive-side annular face 4 Outer shell 5 Flat 6 Not used 7 Pin 8 Inner shell 9 Bridge member 10 Face 11 Driven-side annular face 12 Longitudinal wall 13 space 14 First transverse wall 15 Projection 16 Recess 17 Second transverse wall 18 Lug 19 Clearance 20 Edge region 21 Underside 22 Securing ring 23 Annular wall 24 Extension 25 Reception