Assembly for a variable-lift valve train of an internal combustion engine with two intermediate levers and a carrier therefor

Abstract

A component for a variable-lift valve train of an internal combustion engine is proposed, having two intermediate levers and a common carrier therefor, the carrier serving to fasten the component to a cylinder head of the internal combustion engine, wherein each intermediate lever has a bore at its upper portion for rotatable movement on the carrier and a longitudinally intermediate section which carries a rolling mechanism for the counter-movement of a lifting cam, which longitudinally intermediate section transitions on the underside into a base which widens the intermediate lever in its pivoting direction with a base bulge and has on its underside a sliding slot track for contact with a valve opener. It is emphasized that the two intermediate levers enclose the carrier in its height at its upper portion between their mutually facing outer walls, the axially projecting shaft ends and each one of the intermediate levers which enclose the carrier thereon, wherein the bore of the respective intermediate lever widens via a flange projecting from its outer wall, and wherein each intermediate lever exists as a substantially flat plate.

Description

TECHNICAL FIELD

[0001] The invention relates to an assembly for a variable-lift valve train of an internal combustion engine, with two intermediate levers and a common carrier therefor, the carrier serving to fasten the assembly to a cylinder head of the internal combustion engine, wherein each intermediate lever has a bore at its upper part for rotatable movement on the carrier and a longitudinally intermediate section which carries a rolling mechanism for at least indirect counter-movement of a lifting cam, which longitudinally intermediate section transitions on the underside into a base which expands at least on one side in the pivot direction of the intermediate lever with a base projection and has on the underside of the base a slide track for contact with a valve opener, and wherein the intermediate lever has an abutment for a leg of a cam return spring. BACKGROUND

[0002] Such assemblies are known from CN 206889041 U with reference to Fig. 3 and Figure 1 , 2 resulting therefrom. The carrier there consists of a transverse bridge with forked end portions. Each end portion has a tube-like projection with a peg therein. On the projecting end of the peg, the intermediate lever is hingedly joined to the outer end side of the respective projection via the forked split end of its upper part.

[0003] Furthermore, the documents CN 206889038 U and DE 10 2018 132 561 A1 are referred to. From the documents respectively an intermediate lever is known which has spaced-apart side walls and a forked end portion for being arranged on a carrier. SUMMARY

[0004] It is an object to develop an assembly which is of simple construction and is particularly space-saving.

[0005] According to the invention, the object is achieved in that the two intermediate levers enclose the carrier in the height of their upper parts between their mutually facing outer walls, the axially projecting end portions on the one hand and the respective intermediate lever on the other hand shroud the carrier, wherein the bore of the respective intermediate lever is widened via a flange which projects from its outer wall on one or both sides in one piece, wherein each intermediate lever is present as a substantially flat plate, and wherein the rolling mechanism is two discs which respectively extend on the outer wall at the longitudinally intermediate section.

[0006] Due to the measures, assemblies are realized which are easily constructed and have a not complicated construction. It is determined, however, that by placing the carrier, for example only similar to a slider, "centrally" between two intermediate rods and its simple basic geometry as a flat plate, lateral construction space is gained in a conspicuous manner. In other words, the assemblies are very compactly constructed. Thus, the unit can be used well, for example, in a 3- or 4-cylinder engine arranged below, i.e. on the intake side thereof. At the same time, the tendency of the intermediate rods of narrow construction to invert is prevented by their widened bearing hole, which is preferably joined in one piece. In the case of an intermediate rod constructed in a stamped manner from a sheet metal plate, the widening of the hole seat is caused by a simple passage.

[0007] The intermediate rods can be moved in a pivoting manner independently of one another. Their actuation takes place, for example, indirectly via a corresponding lift cam, between which a suspended roller loaded by an eccentric is inserted. Alternatively, the lift cam can also change its axial position relative to the intermediate rod (start on its disc).

[0008] Alternatively to the particularly preferred sheet metal construction, the intermediate rods can also be manufactured in a MIM method, extruded or forged.

[0009] According to a further embodiment of the invention, the lower base is present widened with respect to the further rod region by means of a sliding groove track. This can be realized, for example, by stamping. The widening provides a good running track for the reverse movement at the valve opener, which can be, for example, a rod-shaped cam follower, such as a tappet or a rocker arm. Alternatively, a roller lifter is also considered.

[0010] Furthermore, a simple abutment and guidance of the end legs of the helical torsion spring on the respective intermediate rod is proposed. This is to be present as a one-piece, fork-shaped opening on the end side of the base. The protruding lateral guidance of the end legs takes place between the two prongs of the fork. Depending on its orientation with respect to the intermediate rod, the fork-shaped opening can here extend upright or transversely.

[0011] A further embodiment relates to the spacing of the flange-like elevations from the side wall of the intermediate rod. The spacing is thus at least half the thickness of the intermediate rod on each side. If necessary, a separate sleeve for widening the hole of the intermediate rod can also be inserted therein.

[0012] The preferably slider-like or beam-like simple carrier has, according to a further embodiment, a continuous shaft, which protrudes on both sides from the carrier by means of shaft ends. The intermediate rods can be fixed axially on the shaft ends, for example via a collar slot. A protrusion of the end side of the shaft end, for example by pressing, is also considered.

[0013] Finally, according to a further development of the application, the carrier is to be provided completely preassembled with the two intermediate rods thereon to the internal combustion engine and is to be installed there as an assembly. This saves installation effort at the engine manufacturer and can prevent incorrect installation. It is also proposed that the assembly is connected with other assemblies of the same kind, for example the number of cylinders to be assembled. BRIEF DESCRIPTION OF DRAWINGS

[0014] With regard to the drawings:

[0015] Figure 1 shows a front view of the complete assembly with the carrier and the two intermediate rods thereon, and

[0016] Figure 2 shows a perspective view of the intermediate rod. DETAILED DESCRIPTION

[0017] From Figure 1 an assembly 1 for a variable-lift valve train of an internal combustion engine is derived. As can be seen, the assembly 1 is composed of a central carrier 3, with one intermediate rod 2 placed on either side of the carrier. The carrier 3 has a continuous shaft 17 with two protruding shaft ends 14. On each of the shaft ends 14, an intermediate rod 2 is pivotably mounted. The assembly 1 can be provided preassembled to the cylinder head of the internal combustion engine, as shown, for final installation.

[0018] Each intermediate rod 2, which exists as a flat steel sheet, has a hole 5 at its upper portion 4 for rotatable mounting on the respective shaft end 14 of the shaft 17 mounted in the carrier 3 (see Figure 2 ). The hole 5 is widened on both sides by means of a respective flange 15. In the longitudinal middle section 6, the intermediate rod 2 has a rolling mechanism 7, which here exists as a disc. The disc 7 serves in a rolling bearing manner, also taking into account a sliding bearing, for the activation of a "flying" intermediate roller, which in turn is loaded by a lift cam and an eccentric (see introductory part of the description).

[0019] The intermediate rod 2 transitions below the disc 7 into a widened base 8, which is expanded on one side by means of a base protrusion 9 (see Figure 2 ). On the front side (end side 16), the base protrusion 9 has a fork-like abutment 12 for the end leg of a cam return spring, also called an idling spring. The end leg here acts upright. On the lower side 10, the base 8 has a slide rail 11 for contact with a valve opener, for example a tappet.

[0020] LIST OF REFERENCE NUMBERS:

[0021] 1) assembly

[0022] 2) intermediate rod

[0023] 3) carrier

[0024] 4) upper portion

[0025] 5) hole

[0026] 6) longitudinal middle section

[0027] 7) rolling mechanism, disc

[0028] 8) base

[0029] 9) base protrusion

[0030] 10) underside

[0031] 11) sliding groove track

[0032] 12) abutment

[0033] 13) outer wall

[0034] 14) shaft end

[0035] 15) flange

[0036] 16) end side

[0037] 17) shaft

Claims

1. An assembly (1) for a variable lift valve train for an internal combustion engine, having two intermediate rods (2) and a common support (3) thereto for securing the assembly to the cylinder head of the internal combustion engine, wherein each intermediate rod (2) has a hole (5) at its upper portion (4) for rotatably mounted on the support (3), and its longitudinal intermediate section (6) carries a rolling mechanism (7) for at least indirect reverse movement of a lifting cam, the longitudinal intermediate section (6) transitioning on its lower side. In the base (8), the intermediate rod (2) is widened at least on one side by a base protrusion (9) when viewed in its pivot direction and has a grooved track (11) on the lower side (10) of the base for contact with the valve opener, and wherein the intermediate rod (2) has abutment (12) for a leg of a cam return spring, wherein each intermediate rod (2) exists as a substantially flat plate, and wherein the rolling mechanism (7) consists of two discs extending on the outer wall (13) of the longitudinal intermediate section (6), respectively. Its features are, Two intermediate rods (2) enclose the support member (3) at the height of its upper portion (4) between its opposing outer walls (13), the support member (3) having a shaft end (14) extending on both sides, each shaft end having an intermediate rod (2), wherein the hole (5) of the corresponding intermediate rod (2) is widened by a flange (15) extending one piece from its outer wall (13) on one or both sides.

2. The component according to claim 1, Its features are, The base (8) below the disc (7) is a transversely thickened portion that is integrally joined to the longitudinal middle section (6).

3. The component according to claim 1 or 2, Its features are, The abutment (12) of the leg for the cam return spring is located on the end side (16) of the base (8) and is configured as a fork-shaped opening.

4. The component according to claim 1, Its features are, The corresponding flange (15) extends at the intermediate rod (2) at a distance from its outer wall (13), the distance being at least half the thickness of the intermediate rod (2).

5. The component according to claim 1, Its features are, The shaft end (14) of the bearing member (3) is either an end piece that extends laterally through the shaft (17) or exists as a shoulder of a one-piece joint.

6. The component according to claim 1, Its features are, The intermediate rod (2) is made of steel plate.

7. The component according to any one of the preceding claims, Its features are, The component (1) is provided externally to the internal combustion engine and is connected thereto to the cylinder head of the internal combustion engine.

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