Lightweight-construction roller tappet

Abstract

This disclosure relates to a roller tappet, in particular for a high-pressure fuel pump. The roller tappet is guided in a direction of a longitudinal axis thereof in a housing receptacle and is driven in the longitudinal direction by cams of a camshaft. The roller tappet has a tappet body. The tappet body has a tappet skirt, a pump piston contact seat, and a rotatably mounted roller, by means of which the roller tappet is supported on the camshaft. The tappet body has a guide cylinder, which is mounted in the housing receptacle and on which the roller is mounted, and a cup-shaped sleeve having the pump piston contact point, which cup-shaped sleeve is supported axially and radially in the guide cylinder.

Claims

1. A multi-part roller tappet for a high-pressure fuel pump, the roller tappet comprising: a tappet body including: a guide cylinder configured to rotatably support a roller, the guide cylinder having a cylindrical constriction groove; and, a cup-shaped sleeve arranged at least partially within the guide cylinder, the cup-shaped sleeve having: a pump piston contact seat; a radially outward-facing radial ring arranged between axial ends of the cup-shaped sleeve, the radial ring secured on an inner lateral surface of the constriction groove; and, an end ring with a radially projecting bead, the end ring located in a region of an axial end of the guide cylinder which is close to the roller.

2. The roller tappet as claimed in claim 1, wherein the guide cylinder is configured with a continuous opening.

3. The roller tappet as claimed in claim 1, wherein an equalizing opening is arranged in the cup-shaped sleeve.

4. The roller tappet as claimed in claim 1, wherein the cup-shaped sleeve has a dome-shaped support at the pump piston contact seat.

5. The roller tappet as claimed in claim 1, wherein the guide cylinder extends beyond the constriction groove at an end of the guide cylinder remote from the roller.

6. The roller tappet as claimed in claim 1, wherein the inner lateral surface of the constriction groove projects radially inward.

7. The multi-part roller tappet as claimed in claim 1, wherein the radial ring is secured on the inner lateral surface of the constriction groove by one of either a press-fit, adhesive bond, or a weld.

8. The multi-part roller tappet as claimed in claim 1, wherein the radially projecting bead rests axially against two supports arranged within the guide cylinder.

9. A multi-part roller tappet for a high-pressure fuel pump, the roller tappet comprising: a tappet body including: a guide cylinder configured to rotatably support a roller, the guide cylinder having a cylindrical constriction groove; and, a cup-shaped sleeve arranged at least partially within the guide cylinder, the cup-shaped sleeve having: a pump piston contact seat, the pump piston contact seat and the roller located at opposite ends of the roller tappet; and, a radially outward-facing radial ring arranged between axial ends of the cup-shaped sleeve, the radial ring secured on an inner lateral surface of the constriction groove.

10. The multi-part roller tappet as claimed in claim 9, wherein the guide cylinder further comprises two supports, each of the two supports having a hole that receives a pin which rotatably supports the roller.

11. The multi-part roller tappet as claimed in claim 9, wherein a lateral surface region of the guide cylinder extends beyond the constriction groove at an end remote from the roller.

12. The multi-part roller tappet as claimed in claim 11, wherein the lateral surface region of the guide cylinder extends beyond the pump piston contact seat.

13. A multi-part roller tappet for a high-pressure fuel pump, the roller tappet comprising: a tappet body including: a guide cylinder configured to rotatably support a roller, the guide cylinder having a cylindrical constriction groove; and, a cup-shaped sleeve arranged at least partially within the guide cylinder, the cup-shaped sleeve having: a pump piston contract seat; a radially outward-facing radial ring arranged between axial end of the cup-shaped sleeve, the radial ring secured on an inner lateral surface of the constriction groove; and, an equalizing opening arranged between the pump piston contact seat and the radial ring.

14. The multi-part roller tappet as claimed in claim 13, wherein the inner lateral surface of the constriction groove projects radially inward.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure is described in the drawings:

(2) FIG. 1 shows a perspective view of a roller tappet according to the disclosure,

(3) FIG. 2 shows the roller tappet according to FIG. 1 and the components thereof in an exploded illustration,

(4) FIGS. 3 and 4 show sections through the roller tappet according to FIG. 1, which are rotated through 90 relative to one another, and

(5) FIGS. 5 and 6 show sections through a roller tappet similar to those in FIGS. 3 and 4, but where the guide cylinder is extended at the end remote from the roller.

DETAILED DESCRIPTION

(6) In FIGS. 1 to 6, where illustrated in detail, 1 denotes a guide cylinder, which has supports 2 and 3, on which a pin 4, a bearing sleeve 5 and a roller 6 are mounted. At a distance from the roller 6, the guide cylinder 1 has a constriction groove 7. In the illustrative embodiments according to FIGS. 1 to 4, the guide cylinder 1 is of short design and ends at the end of the constriction groove 7. However, according to FIGS. 5 and 6, it is also possible for the guide cylinder 1 to be of extended design, there thus being a further lateral surface region adjoining the constriction groove 7. Inserted into the guide cylinder 1 is a cup-shaped sleeve denoted by 8, which has, at its upper end, that remote from the roller 6, a pump piston contact seat 9, which has a dome-shaped support 10 with a thick wall. The cup-shaped sleeve 8 is supported in the guide cylinder 1 by means of an end ring 11, wherein the end ring 11 has a radially projecting bead, which is matched to the supporting surface in the guide cylinder 1. A radial ring 12, which is designed to be an accurate fit with the inner wall of the constriction groove 7, is provided on the cup-shaped sleeve 8 at the level of the constriction groove 7. The radial ring 12 can be press-fitted, adhesively bonded, welded or connected in some similar way to the inner lateral surface of the constriction groove 7. In order to provide a pressure balance between the pump unit (not illustrated) and the camshaft chamber (not illustrated), an equalizing opening 13 is machined into the wall of the cup-shaped sleeve 8.

LIST OF REFERENCE CHARACTERS

(7) 1 guide cylinder 2, 3 supports 4 pin 5 bearing sleeve 6 roller 7 constriction groove 8 cup-shaped sleeve 9 pump piston contact seat 10 dome-shaped support 11 end ring 12 radial ring 13 equalizing opening