CN112483213A

CN112483213A - Module for a variable valve drive of an internal combustion engine

Info

Publication number: CN112483213A
Application number: CN201910863504.9A
Authority: CN
Inventors: V·施密特; W·克里斯滕
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Holding China Co Ltd
Priority date: 2019-09-12
Filing date: 2019-09-12
Publication date: 2021-03-12

Abstract

The invention relates to a module (1) of a variable valve drive of an internal combustion engine, comprising a push rod (3) mounted in a cylinder head (2) of the internal combustion engine in the longitudinal direction, said push rod having actuating fingers (4) depending therefrom, the push rod (3) being assigned a linear actuator (5), the armature (6) of which is in contact with the push rod in order to displace the push rod in the longitudinal direction (A), wherein each actuating finger (4) is assigned a switchable valve rod (7) having a coupling slide (8) extending therein transversely to the longitudinal extension thereof, the slide (9) of the coupling slide (8) projecting laterally from the valve rod (7) and being acted upon by a free end (10) of the actuating finger (4) of the push rod, wherein the slide of the push rod (3) is at least partially converted in the longitudinal direction (A) and before the final position of the push rod by means (11) of a separate damping means Energy of motion.

Description

Module for a variable valve drive of an internal combustion engine

Technical Field

The invention relates to a module of a variable valve train of an internal combustion engine, comprising a push rod which is mounted in the cylinder head of the internal combustion engine in the longitudinal direction and has an actuating finger which projects therefrom, a linear actuator being associated with the push rod, the armature of which is at least indirectly in contact with the push rod in order to displace the push rod in one longitudinal direction, wherein a switchable valve push rod is associated with each actuating finger, the valve push rod having a coupling slide element which extends therein transversely to the longitudinal extension thereof, the slide element of the coupling slide element projecting laterally from the valve push rod and being acted upon by the free end of the actuating finger of the push rod.

Background

Such modules with actuator-loaded push rods, actuating fingers thereon and valve struts are also referred to as electric rocker modules (eRocker-Module) or rocker systems. An example of this is known from DE 102017101792. In this case, the gas exchange valves of the cylinder banks of the internal combustion engine, which are functionally identical in one bank of cylinder heads, are each assigned a tappet with an end-side actuator, in this case an electric actuator. Each cylinder is provided with two identically acting gas exchange valves. When the actuator is not energized, the tappet is reset by the force of the servo means, in this case a compression spring.

The disadvantage of the above-described configuration is that the tappet emits structure-borne sound when it suddenly reaches one of its two end positions. These frequencies may be in the audible range and thus in the comfort region. A "hard" stop (solid edge) of the cylinder head may be considered as an end/reversal point of the tappet in the direction of extension of the actuator. In the retraction direction of the actuator, either the same reverse stop can be considered and provided or a stop for the armature of the actuator can be considered and provided in the actuator. Depending on the configuration of the composite structure of the armature and the tappet of the actuator, the tappet may also be briefly released from the armature when it is suddenly braked at the stop and may again strike in the event of a noise.

Disclosure of Invention

The object of the invention is therefore to provide a module of the type mentioned above, which can be operated with low noise.

According to the invention, this object is achieved by: the kinetic energy of the tappet is at least partially converted by a separate damper element before the final position of the tappet, at least in the longitudinal direction away from the linear actuator, wherein, according to a preferred embodiment of the invention, elastic solids (elastomers, plastics, rubbers), gas dampers or fluid dampers are particularly considered as dampers.

In a simplest variant, a rubber element is therefore arranged on the plunger, for example on its free end face, by means of which the kinetic energy of the plunger is "cancelled" or, more precisely, converted in the event of an extension and stop caused by the actuator, so that the plunger reaches its end position more "softly" and without audible noise. The vibration damper can also be located on a mating contour (gegenkontru) of the cylinder head. Likewise, the other rearward end point in the actuator can be provided with mechanical damping means or the final position can also be "damped" by the aforementioned measures on the tappet or the cylinder head. If necessary, damping means, such as elastic solids, can also be arranged on each of these profiles (tappet and cylinder head) with one or two stops.

Alternatively, gas dampers or fluid dampers may be considered. Both dampers can have a clearly progressive characteristic curve, so that the damper can also be connected to the tappet continuously at least in the extension direction. A fluid damper can also be understood as a leakage play element, for example, as is known from the valve train technology as a hydraulic play compensation element or as installed in a chain or belt clamping device.

According to a further development of the invention, the plunger (wherein the plunger set can also always be considered) is to be loaded in its retraction direction by a mechanical spring means. In this case, at least one helical compression spring can be considered, which is supported at one end on the cylinder head. Alternatively, the push rod can also be acted upon by an actuator, for example an electric actuator, in its retracted position.

Instead of the free end of the tappet for contact with the damper, an arm can also project from the tappet, which arm is connected to the damper of the cylinder head or itself has the damper for "hard" cylinder head contact.

It is also advantageous to integrate the damping means and the pressure spring means in one preassembled assembly. However, their separate use is also conceivable, for example, in the case of installation space problems.

According to an expedient further development of the invention, the adjusting finger projecting from the tappet is designed as a leaf spring tongue (Federzunge), but in other cases it can also be a "rigid" finger.

Drawings

Figure 1 shows a first variant with damping means and spring means separated from each other,

fig. 2 shows a partial view as described above, wherein the damping means and the spring means form a structural unit.

Detailed Description

Fig. 1 and 2 show a module 1 of a variable valve drive of an internal combustion engine. This module 1 is also referred to as an electric rocker module or an electric rocker system.

The module 1 consists of a tappet 3 supported along it in a cylinder head 2 of the internal combustion engine. From this push rod, in each case an actuating switchable valve push rod 7, an actuating finger 4 in the form of a leaf spring tongue is suspended. As is disclosed in fig. 1, a linear actuator 5, which is designed here as an electric actuator (electromagnet), is arranged in line on its end face 19, which is drawn here to the right, in front of the tappet 3. The armature 6 of the linear actuator 5 acts directly on the aforementioned end face 19 to displace the tappet 3 in its longitudinal direction a.

Each adjusting finger 4 cooperates with a switchable valve lever 7 which is a further module component. The valve struts 7 (which need not be explained further in this respect) each consist of a box-like outer rod 15 which encloses an inner rod 16. The valve plunger 7 has a support 17 on the lower side (facing away from the camshaft) at one longitudinal end for pivotable mounting on a support element and a valve contact 18 at the other longitudinal end.

A coupling slide 8, which in the simplest case consists of exactly one slide 9, extends laterally from the side of each valve plunger 7 to be switched, wherein, however, preferably two or three slides are provided. The slide 9 is acted upon by the free end 10 of its adjusting finger 4, as can be seen from the two drawings. In both figures, it is shown that the adjusting fingers 4 are not in contact with their slides 9, which is an unswitched state of the module 1. If necessary, the adjusting fingers can also be in contact with their sliding parts in this state.

In order to synchronously couple (or alternatively synchronously decouple) all identically acting valve struts 7, the electric actuator 5 is energized, as a result of which the armature 6 of the electric actuator displaces the tappet 3 in the two figures from right to left in this case against the force of the compression spring means 13. The bendable adjusting fingers 4 are pretensioned on their slides 9, which slides 9 can be suddenly displaced during a cam base circle rotation (nockengrundkreisdurchikuff). According to fig. 1, the push rod 3 undergoes a final limit of displacement at a "hard" stop 12. The latter is a simple solid edge on the cylinder head 2.

According to fig. 1, a damping means 11 is arranged on the module 1 spatially separated from the compression spring means 13. The damping means are drawn here only as symbols and consist in the simplest case of a single elastic solid. An arm 20 connected thereto projects from the tappet 3, which is a structural unit having an armature 6, which arm comes into contact with the damping means 11 when the armature 6 moves with the tappet 3 in the direction a or is in contact with the damping means from the beginning.

By this configuration, the tappet 3 does not experience sudden braking in its final position, which is accompanied by noise and increased wear. Instead, at least a part of the kinetic energy of the push rod 3 is converted in the damping means 11.

If the electrical actuator 5 is de-energized, the push rod 3 is displaced back in the actuator direction B via the pressure spring means 13 in a manner which accompanies the simultaneous "detachment" of the adjusting finger 4 from its slide 9. The latter is loaded in the direction of extension (to the right here) in its respective valve rod 7 by spring means, not shown, and is abruptly displaced outwards as drawn when the cam base circle rotates.

According to the arrangement of fig. 2, the damping means and the compression spring means 11,13 are integrated in one component 14.

List of reference numerals

1 Module

2 Cylinder cover

3 push rod

4 adjusting finger

5 Linear actuator, electric actuator

6 armature

7 air valve compression bar

8 coupling slip device

9 sliding part

10 end of

11 vibration damping device

12 stop

13 pressure spring device

14 assembly

15 outer rod

16 inner rod

17 support part

18 valve contact portion

19 end side

20 arm

A) Longitudinal direction

B) Another longitudinal direction

Claims

1. A module (1) of a variable valve train of an internal combustion engine, having a push rod (3) which is mounted in a cylinder head (2) of the internal combustion engine along the push rod and has actuating fingers (4) which project from the push rod, a linear actuator (5) being assigned to the push rod (3), the armature (6) of which comes into contact at least indirectly with the push rod in order to displace the push rod in a longitudinal direction (A), wherein a switchable valve stem (7) is assigned to each actuating finger (4), which valve stem has a coupling slide (8) which extends transversely to its longitudinal extension, the slide (9) of the coupling slide (8) projecting laterally from the valve stem (7) and being acted upon by a free end (10) of the actuating finger (4) of the push rod, characterized in that, the kinetic energy of the tappet (3) is at least partially converted by a separate damping means (11) before the final position of the tappet at least along the one longitudinal direction (A).

2. Module according to claim 1, characterized in that an electric actuator is applied as the linear actuator (5).

3. Module according to claim 1, characterized in that the final position is determined by a "hard" stop (12) on the head (2).

4. Module according to claim 1, characterized in that the return of the tappet (3) in its other longitudinal direction (B) is achieved by means of a pressure spring device (13) clamped between the tappet and the cylinder head (2).

5. Module according to claim 4, characterized in that the damping means and the pressure spring means (11,13) are either integrated in one component (14) or are present separately in space.

6. Module according to claim 1, characterized in that the damping means (11) is either a) an elastic solid, or b) a gas damper, or c) a fluid damper.

7. Module according to claim 1, characterized in that the adjusting finger (4) is a leaf spring tongue.