EP1472438B1 - Switch element for valve actuation in an internal combustion engine - Google Patents

Abstract

The invention proposes a switching element (1) for a valve train of an internal combustion engine, particularly for valve deactivation, with a simple-to-implement measure for adjusting the coupling lash of its coupling means (8) in a receptacle (6) using two retaining rings (19, 20), one of which is stocked in a variety of thicknesses.

Description

Field of the invention

The invention relates to a switching element for a valve train of an internal combustion engine, preferably for valve shutdown, with an outer part and a in the bore axially movable inner element, wherein the outer part and the Inner element in an achieved by a lost-motion spring axially removed relative position at least each have a mutually aligned recording, wherein in one of the recordings towards the other recording one or more displaceable Coupling means for coupling the inner member with the outer part at the relative position are applied to each other, wherein between the inner element and the outer part a first height stop for defining the relative position is applied and wherein in the inner element, a hydraulic clearance compensation element is installed with a pressure piston, which pressure piston axially this is fixed out by a second height stop.

Background of the invention

Such a switching element goes from the considered as generic forming DE 199 15 531. It is here as a switchable cam follower for a push rod drive shown. Here is a height stop for defining the relative position via a piston-like element arranged in the inner element produced. This protrudes radially outward into a longitudinal groove of the outer part. In the axial apart driven condition of the inner element strikes the outer part the element at one end of the longitudinal groove. Thus, an aligned assignment a positioned in the outer part coupling hole for a in the inner element arranged piston to be created for coupling.

It is disadvantageous in the aforementioned prior art that a setting the game of coupling is relatively complicated and expensive. It's clear, that the corresponding receptacle in the outer part (coupling hole here) for recording the piston slightly play with respect to an outer jacket of the piston must be formed. This game and a high altitude varies due to production of switching element to switching element. The relative wide variance of this mechanical void in the switching elements is however undesirable.

Therefore, to adjust the coupling play or its variance in a bearable To measure, the pistons are grouped to lock. This is Extremely complex in terms of production and metrology. For example Switching elements completely assembled, then the game is measured to then dismantle the switching element again and a corresponding Zuzupaaren piston for coupling. Likewise, it is conceivable, the height stop to group on the longitudinal groove of the outer element.

Another height stop is the o. G. Prior art for a pressure piston provided the lash adjuster and formed as a ring.

If two pistons are provided for coupling, as is known from DE 42 06 166 shows, the o. g. Impact measures virtually impossible. Here, the aligned position of the inner element is diametrically opposite lying coupling holes on conditioning of the two axially movable parts realized the switching element on the cam base circle. A setting of the Play the coupling takes place here manufacturing and metrology extremely complex via a pairing of corresponding switching elements (here bucket tappets) with cam pairs or shafts. Possibly. will be too big a game deviation must be approved.

Object of the invention

The object of the invention is therefore to a switching element of the aforementioned type in which eliminates the cited disadvantages with simple means are.

Summary of the invention

• dass die Höhenanschläge als jeweils mindestens ein ringartiges Element wie ein Sicherungsring ausgebildet und übereinander liegend in der Bohrung des Außenteils angeordnet sind, wobei in die Bohrung des Außenteils gesehen der untere Sicherungsring den zweiten Höhenanschlag und der darüberliegende erste Sicherungsring den ersten Höhenanschlag bildet, wobei bei Montage der Sicherungsringe dickenvariable erste und dickenkonstante zweite Sicherungsringe vorgesehen sind und wobei das Sicherungsringpaket über den ersten Sicherungsring aus der Bohrung heraus an einem Anschlag wie einem Ringabsatz der Bohrung anliegt.

According to the invention, this object is achieved by

• that the height stops are each formed as at least one ring-like element as a retaining ring and lying one above the other in the bore of the outer part, wherein seen in the bore of the outer part of the lower retaining ring the second height stop and the overlying first locking ring forms the first height stop, wherein during assembly the retaining rings are provided with thickness-variable first and thick-constant second securing rings, and wherein the securing ring package bears against a stop such as an annular shoulder of the bore via the first securing ring out of the bore.

Due to the at least two or two retaining rings results in a simple, non-tilting and adjustable height stop as well as a captive safety device for the pressure piston of the hydraulic lash adjuster. Preferably two coupling means (piston) should be provided in the inner element. equally However, the scope of the invention also relates to a Embodiment with only one piston or with a plurality of pistons.

The subordinate claim 8 alternatively relates to a method for adjustment the coupling play in a switching element according to the features of Preamble of claim 1.

By the aforementioned measures are the disadvantages cited above simple means and effectively eliminated. For one thing, when mounting the Switching element guarantees that the pressure piston of the lash adjuster and Thus, the inner element is not lost (second height stop). To the Another results from the variable thickness held ready first retaining rings as the first height stops a very easy way, the free travel of the at least one coupling element (piston) with respect to its enclosing To stop recording. Preferably, this free travel is adjusted so that each Aufriahme the corresponding coupling means equidistant in both axial directions encloses. Should the receptacle be a hole and not an annular groove, so it is particularly advantageous if the bore the corresponding coupling agent concentrically.

Instead of the retaining rings will be apparent to the skilled person at this point even more easily mounted slings, such as discs, usable pins, Wedges, rings, etc. Also, these funds can of course be on another Height section can be arranged as the edge side of the switching element. Possibly. several circlips can be paired to each other to the coupling play or to realize the captive protection.

Thus, it is guaranteed that in the corresponding coupling case, the coupling agent in the them enclosing receiving the outer part, via a plurality of switching elements away, always traversing the same empty path.

Preferably, as mentioned, two pistons are provided as coupling means, which run in the formed as a radial bore receiving the inner element and there are diametrically opposite. This is a particularly tip over Mechanism that generates only a small component load when coupled. Instead of the radial bore in the inner element is also a blind hole or a similar embodiment conceivable.

In a further development of the invention, it is proposed to accommodate the outer part, as previously mentioned, to manufacture as an annular groove in the bore. this has in particular manufacturing advantages. In place of the annular groove can also Boreholes are arranged.

According to a further advantageous concretization of the invention, the inner element relative to the outer part, for example via a pin-like element against rotation. Thus, the coupling agents have in terms of their absorption over the same positioning over the entire operating period of the switching element as in the setting of the coupling game. As a result, tolerances, in the case of training the recording as a circumferential groove, not more out.

Likewise, it is suggested the annular groove, in the case of using two Piston as a coupling agent, of two diametrically opposite oil passages how to have holes cut. Are two supply lines in an oil gallery a surrounding structure such as a cylinder head or a provided with the internal combustion engine guide for the switching element, which are opposite, it does not matter which oil passage of the switching element with which supply line communicates. Important are the same length of oil routes to Achieving equal switching times. In the case of only one lead, however, is a directed Installation of the switching element necessary. Here can appropriate markings attached to this for ease of assembly. Of course the oil passages in the outer part also at another peripheral portion This should be arranged so that it does not reach the piston in the coupling case aligned.

In the event that the switching element as a cam follower in a push rod drive is made, as proposed in further expedient development of the invention is, and this cam follower has a role as a cam counter-rotor, and for the assignment of the supply lines from the surrounding construction to the Oil passages, it is necessary to twist the switching element. Here are appropriate anti-rotation measures such as flattening on the outer jacket of the outer part proposed.

Instead of the piston as a coupling agent, other elements such as pawls, Spheres, wedges and similar form-fitting generating elements used become. Possibly. is also a form-frictional conceivable.

The scope of this invention expressly relates to all types of Switching elements in valve trains, such as the aforementioned cam followers in pushrod drives, Cup tappets or support elements for drag levers etc ..

Short description of the drawing

Figur 1

einen Längsschnitt durch ein als Rollenstößel für einen Stößelstangentrieb ausgebildetes Schaltelement und

Figur 2

einen um 90° gedrehten Teillängsschnitt nach Figur 1.

The invention is suitably explained in more detail with reference to the drawing. Show it:

FIG. 1

a longitudinal section through a designed as a roller tappet for a push rod drive switching element and

FIG. 2

a rotated by 90 ° partial longitudinal section of Figure 1.

Detailed description of the drawing

Figures 1, 2 disclose a switching element 1 for a valve train a Internal combustion engine. This is here as a roller plunger for a pushrod shoot educated. It consists of an outer part 2, in the bore 3 a axially movable inner element 4 extends. The inner element 4 and the outer part 2 are separated by a not-to-explain Lost-motion spring 5 from each other acted upon.

In the illustrated axially spaced apart position of the Outer part 2 to the inner element 4 are aligned with their receptacles 6, 7 to each other. The receptacle 6 of the outer part 2 is made as a circumferential annular groove. The Recording 7 in the inner element 4, however, is as a radial through hole educated. In this are two diametrically opposite ones Coupling means 8 arranged, which are designed here as a piston. The Coupling means 8 are radially outward on the force of a compression spring means 10th acted upon (coupling direction). Radial inwards, d. H. in decoupling direction, the coupling means 8 can be displaced via hydraulic means. For this has the outer part 2 expediently two diametrically opposite Oil passages 11 (see Figure 1). These are made here as a bore and around Offset 90 ° to the coupling means 8 in the circumferential direction. Conveniently, communicate the oil passages 11 with two supply lines for hydraulic fluid from a non-descriptive surrounding construction.

Furthermore, the person skilled in the figures can be seen that on the outer jacket 12 of the outer part 2 means 13 are applied to prevent rotation. These are formed here as opposing flattenings. These Action proves to be necessary to the oil passages 11 with their to connect appropriate supply lines and, second, to a role 14 to align with a cam, not shown.

Furthermore, it can be seen that the inner element 4 with respect to the outer part 2 is also secured against rotation. For this purpose, in the outer part 2 a rotation 15 (designed here as a pin) attached, which radially into the bore 3 of the outer part 2 protrudes. The inner element 4 in turn has one of Anti-rotation 15 facing longitudinal recess 16, at the edges of the Anti-rotation 15 is guided.

The outer part 2 has in an area remote from the bore an annular groove 17 with a stop 18. In the annular groove 17, two retaining rings 19, 20 are snapped. These each form a second and first height stop 21, 22. The circlips 19, 20 total are at the stop 18. there serves the second, lower retaining ring 19 a captive of a pressure piston 23 of a hydraulic lash adjuster 24, which in the Interior element 4 is installed. About the first locking ring 20, which on the second locking ring 19 and kept available variable thickness during installation is done, there is an adjustment of the coupling play of the coupling means 8 in the surrounding recording 6.

It is clear that the pressure piston 23 with inner element 4 after mounting the second locking ring 19 is no longer out of the bore 3 of the outer part. 2 over the force of a compression spring 25 of the play compensation element 24 and the Lost motion spring 5 can be pushed. The pressure piston 23 is thus via its edge 26 in contact with the second retaining ring 19th

Before setting the coupling play of the coupling means 8 with respect to their recording 6 this must be determined. This is done with extended coupling agents 8. It is simply said their Leerweg in the receptacle 6 after loading of the inner element 4 and thus its displacement in the bore 3 to the Reaching a bottom 27 of the receptacle 6 measured. Then it is relatively easy for a person skilled in the art to calculate back, based on the measured idle travel, at which height a center position of the coupling means 8 in the Recording 6 is reached. After this value is determined, a corresponding thick first circlip 20 directly above the second circlip 19 snapped into the annular groove 17. The lost motion spring 5 thus suppresses the Inner element 4 with its edge 28 against the second retaining ring 19. In this position (coupling position) is the coupling game set; advantageously such that the coupling means 8 in the receptacle 6 in both axial directions has the same low travel paths.

Overall, therefore, a free path, the inner element 4 after Successful coupling with the outer part 2 and the beginning Nockenzubeaufschlagung relative to the outer part 2 with the coupling means 8 in the receptacles. 6 travels evenly over a series of switching elements 1 in Internal combustion engines of the same type are kept. Too big and unwanted Variance of the tax times is excluded.

reference numerals

1

switching element

2

outer part

3

drilling

4

inner element

5

Lost-motion spring

6

Recording outdoor part

7

Recording inner part

8th

coupling means

9

not forgiven

10

Spring means

11

oil passage

12

outer sheath

13

medium

14

role

15

twist

16

longitudinal recess

17

ring groove

18

attack

19

circlip

20

circlip

21

height stop

22

height stop

23

pressure piston

24

Lash adjuster

25

compression spring

26

Edge pressure piston

27

bottom

28

Edge interior element

Claims (8)

1. Switching element (1) for a valve train of an internal combustion engine, preferably for valve deactivation, comprising an outer part (2) and an inner element (4) that is axially displaceable in a bore (3) thereof, said outer part (2) and said inner element (4) comprising at least one reception (6, 7) each, which receptions (6, 7) are aligned to each other in an axially distant relative position effected by a lost motion spring (5), one or more coupling means (8) being arranged in one of the receptions for displacement towards the other reception for coupling the inner element (4) to the outer part (2) in said relative position, a first vertical stop (22) being arranged between the inner element (4) and the outer part (2) for defining said relative position, a hydraulic clearance compensation element (24) comprising a pressure piston (23) being installed in the inner element (4), which pressure piston (23) is fixed in a direction leading axially out of this by a second vertical stop (21), characterised in that each of the vertical stops (21, 22) is configured as at least one annular element such as a securing ring (19, 20) and the vertical stops (21, 22) are arranged on top of each other in the bore (3) of the outer part (2), as seen when looking into the bore (3) of the outer part (2), the lower securing ring (19) forms the second vertical stop (21) and the upper, first securing ring (20) forms the first vertical stop (22), variable-thickness first securing rings and constant-thickness second securing rings being provided for mounting as securing rings (20, 19), and, in a direction leading out of the bore (3), the securing ring stack (20, 19) bears through the first securing ring (20) against a stop (18) such as an annular shoulder of the bore (3).
2. Switching element according to claim 1, characterised in that two pistons are provided as coupling means (8) that extend in the reception (7) of the inner element (4) and are situated there diametrically opposite each other, said reception (7) being configured as a radial bore.
3. Switching element according to claim 2, characterised in that the reception (6) of the outer part (2) is made as an annular groove in the bore (3) thereof and the annular groove is intersected by two opposing oil passages (11) such as bores in the outer part (2), the inner element (4) being guided in the bore (3) of the outer part (2) by an anti-rotation device (15).
4. Switching element according to claim 3, characterised in that a radially protruding element such as a pin is arranged as an anti-rotation device (15) and is fixed in the outer part (2) or the inner element (4) while being guided in a longitudinal recess (16) of the opposing component (inner element (4) or outer part (2)).
5. Switching element according to claim 1, characterised in that the outer part (2) comprises means (13) for the rotation-proof guidance of the entire switching element (1) relative to a surrounding structure.
6. Switching element according to claim 5, characterised in that the means (13) for the rotation-proof guidance consists of one or more flattened portions on the outer peripheral surface (12) of the outer part (2).
7. Switching element according to claim 1, characterised in that the switching element (1) is made as a cam follower in a tappet push rod drive.
8. Method of adjusting the coupling clearance in a switching element (1) according to the features of the preamble of claim 1, each vertical stop (21, 22) being configured as at least one annular element such as a securing ring (19, 20), the bore (3) of the outer element (2) comprising a bore-distal stop (18) such as an annular shoulder, and at least one piston being provided as a coupling means (8) that extends in the reception (7) of the inner element (4), which reception (7) is made as a radial bore, said method comprising following steps between which further intermediate steps are possible:

   a) snapping-in the at least one second securing ring (19) into a region axially below the stop (18) in such a way that the pressure piston (23) of the clearance compensation element (24) is pressed with its bore-distal edge (26) by the force of a compression spring (25) of the clearance compensation element (24) against the second securing ring (19) and this is pressed against the stop (18);

   b) with the coupling means (8) extended into the reception (6) of the outer part (2), displacing the inner element (4) in bore direction till the coupling means (8) comes to bear against a lower surface (27) of the reception (6);

   c) measuring the idling path of the inner element (4) with the coupling means (8) till contact is made with the lower surface (27), and

   d) selecting the at least one first securing ring (20) with such a thickness that when it subsequently snaps into a region axially below the stop (18), and bears against the second securing ring (19), the inner element (4) is displaced by the second securing ring (19) in such a way that the coupling means (8) extends at an equal distance from the reception (6) at least in both axial directions.

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