DE102018117338A1 - Module of a variable valve train of an internal combustion engine - Google Patents

Abstract

Proposed is a module (1) of a variable valve train of an internal combustion engine, with a push rod (3) mounted longitudinally in a cylinder head (2) of the internal combustion engine with adjusting fingers (4) depending thereon, to which push rod (3) a linear actuator (5) is assigned, the armature (6) of which contacts them for their displacement in a longitudinal direction (A), each switch finger (4) having a switchable rocker arm (7) with a coupling slide means (8) extending transversely to its longitudinal extension, of which coupling slide means (8) a slide part (9) protrudes laterally from the rocker arm (7) and a free end (10) of which the actuating finger (4) can be acted upon, and the kinetic energy of the push rod (3) in one longitudinal direction (A) and before its end position via separate damping means (11) is at least partially converted.

Description

The invention relates to a module of a variable valve train of an internal combustion engine, with a push rod mounted longitudinally in a cylinder head of the internal combustion engine with adjuster fingers depending thereon, to which push rod a linear actuator is assigned, the armature of which at least indirectly contacts them for their displacement in a longitudinal direction, with each actuating finger a switchable rocker arm with a coupling slide means running transversely to its longitudinal extent, of which coupling slide means a slide part protrudes laterally from the rocker arm and can be acted upon by a free end of its adjusting finger.

Such modules with actuator-actuated push rod, positioning fingers thereon and rocker arms are now also referred to as eRocker modules or systems. An example of this is given in the DE 10 2017 101 792 out. A push rod with a front-side actuator, here an e-actuator, is assigned to a row of equivalent gas exchange valves in a row of cylinders of an internal combustion engine in the cylinder head. Two equivalent gas exchange valves are provided for each cylinder. The push rod is reset when the actuator is not energized using the force of a servo, here a compression spring.

It is disadvantageous in the aforementioned design that the push rod emits structure-borne noise when one of its two end positions is suddenly reached. These frequencies can be in the audible and therefore in the comfort range. A "hard" stop of the cylinder head (body edge) can be used as the end point / reversal point for the push rod in the actuator extension direction. In their return direction, either a counter stop or a stop for the armature of the actuator in the latter is conceivable and provided. Depending on the design of the actuator armature and push rod assembly, the latter can briefly detach itself from the armature when it suddenly brakes at a stop and strike again with the emission of noise.

The task is to create a module of the aforementioned type, which can be operated with little noise.

According to the invention, this object is achieved in that the kinetic energy of the push rod, which can be a flat sheet, a tube or a solid cylinder, is at least partially converted in a longitudinal direction away from the linear actuator, before its end position, by means of a separate damping means, using as a damper According to a preferred development of the invention, in particular an elastic solid body (elastomer, plastic, rubber), a gas damper or a fluid damper is intended.

In the simplest variant, for example, a rubber piece is attached to the free end face of the push rod, by means of which the kinetic energy of the push rod is "destroyed" or, more precisely, converted in the case of extension and stop caused by the actuator, so that the push rod is comparatively " gently ”and without emitting audible noises, has reached an end position. The damper can also lie on the opposite contour of the cylinder head. Likewise, the other rear end point in the actuator can be provided with a mechanical damping means or this end position can also be “damped” by the aforementioned measures on the push rod or the cylinder head. Possibly. In one or both stop cases, damping means such as elastic solid bodies can also be attached to each of the contours (push rod and cylinder head).

Alternatively, a gas or fluid damper is envisaged. Both dampers can have a clearly progressive characteristic, so that it is also possible to have them permanently connected to the push rod, at least in the direction of extension. Fluid damper is also to be understood to mean, for example, a leakage gap element, as is known from valve train technology as a hydraulic lash adjuster element or is installed in chain or belt tensioners.

According to a further development of the invention, the push rod, with a push rod package always being considered, should be acted upon in its return direction by a mechanical spring means. Here, in particular, at least one helical compression spring is intended, which is supported at one end on the cylinder head. As an alternative to this, the push rod can also be acted upon in its return position by an actuator such as an e-actuator.

Instead of the free end face of the push rod for damper contact, an arm can also protrude from the push rod, which communicates with a damper of the cylinder head or itself has the damper for a “hard” cylinder head contact.

It is also advantageous to combine the damping and compression spring means in a preassembled module. In the case of installation space problems, for example, their separate application can also be considered.

The actuating fingers protruding from the push rod are in accordance with appropriate further training of the invention designed as leaf-like spring tongues, but u. May also be "stiff" fingers.

• • 1 zeigt eine erste Variante eines Moduls mit getrennt voneinander vorliegendem Dämpfungs- und Federmittel und
• • 2 eine Teilansicht wie vorgenannt, wobei Dämpfungs- und Federmittel eine Baueinheit bilden.

For drawing:

• • 1 shows a first variant of a module with separate damping and spring means and
• • 2 a partial view as mentioned above, wherein damping and spring means form a structural unit.

Is shown in the 1 . 2 a module 1 of a variable valve train of an internal combustion engine. This module 1 is also referred to as an e-rocker module or system.

The module 1 consists of one in a cylinder head 2 the internal combustion engine thrust rod 3 , The switchable rocker arm to be activated depends on this 7 an adjusting finger designed as a leaf-like spring tongue 4 from. The push rod 3 is like 1 discloses a linear actuator designed here as an e-actuator (e-magnet) 5 on her forehead drawn here on the right 19 preceded in alignment. An anchor 6 of the linear actuator 5 acts directly on the aforementioned forehead 19 in the sense of a displacement of the push rod 3 in its one longitudinal direction A.

Every finger 4 cooperates with a switchable rocker arm 7 as a further module component. The rocker arm 7 consists of a box-like outer lever, which does not need to be explained further here 15 which has an inner lever 16 surrounds. The rocker arm 7 has a support on one underside (facing away from the camshaft) at one longitudinal end 17 for pivotable mounting on a support element and at another longitudinal end a valve contact 18 ,

From each rocker arm to be switched 7 protrudes laterally across a coupling slide means 8th which, in the simplest case, consists of exactly one slide part 9 exists, but preferably two or three slide parts are provided. The slide part 9 is, as can be seen from both figures, from a free end 10 his finger 4 applied. Here are the control fingers 4 in both figures out of contact from their slide parts 9 drawn what an unswitched state of the module 1 represents. Possibly. the latter components can also be in contact in this state.

To all rocker arms with the same effect 7 Coupling synchronously (or alternatively decoupling), the e-actuator 5 is energized, causing its armature 6 the push rod 3 in both figures here from right to left against the force of a pressure spring 13 relocated. The flexible control fingers 4 are on their slide parts 9 preloaded which slide parts 9 can then be abruptly shifted when the cam runs through the basic circuit. According to 1 experiences the push rod 3 a final limit on a "hard" stop 12 , The latter is a simple body edge on the cylinder head 2 ,

Spatially separated from the pressure spring means 13 is according to 1 a damping agent 11 on the module 1 intended. This is only shown as a symbol and in the simplest case consists of a simple elastic solid. From the push rod 3 which here is a unit with the anchor 6 represents, an arm connected to it protrudes 20 away, which when moving the anchor 6 with push rod 3 towards A in contact with the damping agent 11 comes or is in contact from the start.

The push rod experiences through this design 3 no jerky braking at one end position, accompanied by noise and increased wear. Rather, at least part of the kinetic energy of the push rod 3 in the damping agent 11 changed.

If the current supply to the e-actuator 5 is released, the push rod is moved back 3 in actuator B via the pressure spring means 13 with simultaneous "removal" of the positioning fingers 4 from their slide parts 9 , The latter are in their respective rocker arms 7 spring means (not shown) are applied in the extension direction (here to the right) and are suddenly shifted to the outside as shown in the cam base circuit.

According to 2 it is provided the damping and compression spring means 11 . 13 in one assembly 14 to unite.

LIST OF REFERENCE NUMBERS

1)

module

2)

cylinder head

3)

pushrod

4)

Deputy finger

5)

Linear actuator, e-actuator

6)

anchor

7)

cam follower

8th)

Coupling slide means

9)

slide part

10)

The End

11)

damping means

12)

attack

13)

Spring means

14)

module

15)

external lever

16)

internal lever

17)

support

18)

valve Contact

19)

forehead

20)

poor

A)

a longitudinal direction

B)

other longitudinal direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102017101792 [0002]

Claims (7)

Module (1) of a variable valve train of an internal combustion engine, with a push rod (3) mounted longitudinally in a cylinder head (2) of the internal combustion engine with actuating fingers (4) depending thereon, to which push rod (3) a linear actuator (5) is assigned, the armature ( 6) contacts them at least indirectly for their displacement in a longitudinal direction (A), with each actuating finger (4) having a switchable rocker arm (7) with a coupling slide means (8) running transversely to its longitudinal extension, of which a coupling slide means (8) Slide part (9) protrudes laterally from the rocker arm (7) and its free finger (4) can be acted upon by a free end (10), characterized in that the kinetic energy of the push rod (3), at least in one longitudinal direction (A) the end position of which is at least partially converted via a separate damping means (11). Module after Claim 1 , characterized in that an e-actuator is applied as the linear actuator (5). Module after Claim 1 , characterized in that the one end position is determined by a “hard” stop (12) on the cylinder head (2). Module after Claim 1 , characterized in that the push rod (3) is reset in its further longitudinal direction (B) by means of a pressure spring means (13) clamped between the latter and the cylinder head (2). Module after Claim 4 , characterized in that damping and compression spring means (11, 13) are either combined in one assembly (14) or are each spatially separate. Module after Claim 1 , characterized in that the damping means (11) is either a) an elastic solid, b) a gas damper or c) a fluid damper. Module after Claim 1 , characterized in that the adjusting fingers (4) are leaf-like spring tongues.

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