WO2008122477A1

WO2008122477A1 - Switchable valve train part

Info

Publication number: WO2008122477A1
Application number: PCT/EP2008/052938
Authority: WO
Inventors: Calin Petru Itoafa
Original assignee: Schaeffler Kg
Priority date: 2007-04-05
Filing date: 2008-03-12
Publication date: 2008-10-16
Also published as: DE102007016739A1; KR101465280B1; KR20100015364A; ATE477402T1; DE502008001125D1; CN101680313A; EP2132419A1; WO2008122477A8; EP2132419B1

Abstract

The invention relates to a switchable valve train part (1) such as a bucket tappet, comprising a housing (2) in the bore (3) of which an inner element (4) runs that is axially movable relative to said bore, said inner element comprising a radially continuous bore (6) comprising two coupler pistons (7) located opposite one another that, in order to create a coupled state, may be brought into engagement in sections with a respective crescent-shaped material clearance (14) in the bore (3) of the housing (2).

Description

Name of the invention

Switchable valve drive part

description

Field of the invention

The invention relates to a switchable valve drive part, with a hollow cylindrical housing, in whose bore a relatively axially movable inner element extends with its outer jacket, wherein one of the components [inner element or housing] at least one bore with at least one in the decoupling case extending coupling piston is immanent which bore leads in the direction of the other component and leads to an annular surface between the components, which coupling piston for a coupling case in sections with a cam surface of the other component is engageable and wherein a lost-motion spring means is provided, which the components acted upon in the Ausschieberichtung each other away.

Background of the invention

Such a valve train part, designed here as a bucket tappet, is apparent from the considered as generic forming DE 44 92 633 C1. Its coupling mechanism is located directly below the floor area. The skilled artisan will recognize that the prior art ram is constructed relatively complicated and thus its production proves to be unnecessarily costly. For example, the outer part is not formed symmetrically in the bottom region, since guide bores for the coupling piston are applied below the annular bottom. Also, the inner part is unnecessarily massive and complicated. Due to the aforementioned massive design, the oscillating valve train masses are disadvantageously increased. The piston coupling to be recognized leads to a relatively large surface pressure in the coupling region, it can also lead to unnecessary edge wear in the retraction of the coupling piston.

In addition, prior art solutions are already known, in which the coupling pistons, in the coupling case, retract into an all-round annular groove of the respective other component which is adjacent to the end face. On the one hand, the annular groove weakens the material, so that possibly larger dimensions have to be applied in this area. On the other hand, because of the annular groove, through which the hydraulic fluid is conducted in front of the coupling piston or pistons, relatively long hydraulic fluid paths are present. This can lead to undesirably long switching times or faulty circuits within the available time window (base circle).

Object of the invention

The object of the invention is therefore to provide a switchable valve train part of the aforementioned type, in which the cited disadvantages are eliminated by simple means.

Solution of the task

According to the invention, this object is achieved in that the respective coupling piston, starting from the driver face facing end, is provided on one axial side with a section-wise flattening, wherein the other component, only in the peripheral portion of the adjacent bore with the coupling piston in a component in his Bore / is provided on its outer jacket, with a merely sickle-like material release, on which a flat Axialstirn the driver surface for engagement of the flattening of the coupling piston for the coupling case is shown and where on the one hand, the coupling piston against the bore and on the other hand the components to each other with a respectful rotation are provided. Thus, there is a switchable valve train part in which the cited disadvantages are effectively eliminated. The scope of the invention relates in particular to switchable valve train parts such as bucket tappets, but is not limited thereto. Likewise, switchable roller or flat tappets and switchable supporting elements are included in the scope of protection. All elements can be provided with hydraulic or mechanical clearance compensation.

The idea of the invention relates to solutions with at least one coupling piston, but preferably two diametrically opposed coupling pistons should be applied. However, solutions are also conceivable and provided with a coupling piston number> 2 (star-shaped arrangement).

In the decoupling case, the coupling pistons can sit in the housing and be displaced radially inwardly into their respective sickle-like material release on the outer jacket of the inner part for the coupling case (large cam lift). In addition, the coupling piston in the inner part, for example, in a radial bore, extend and be displaced for the coupling case radially outward in the adjacent sickle-like material release of the bore of the housing. It is expedient if the coupling pistons are provided with a flattening on their corresponding axial side (coupling region), but this is not a condition.

The proposed respective sickle-like Materialfreistellung can be generated in the case of their training in the bore of the housing, for example, by a simple Scheibenfräsvorgang. Also conceivable, however, are other machining operations such as screwing or a non-cutting introduction such as embossing, extrusion or picking.

It is particularly preferred if the switchable valve train part, as mentioned, is designed as a detachable or reversible tappet. As a bore for the preferably two coupling piston is especially thought of a radial bore, which can be easily displayed in one operation. Conceivable and However, it is also provided to apply a blind hole o. The like. For each coupling piston.

In the coupling direction, the coupling pistons are preferably acted upon by compression spring force radially outwards (in the case of their arrangement in the inner part). A shift back in Entkoppelrichtung is made possible in the sickle-like material release each conductive hydraulic fluid.

The respective sickle-like material release weakens only slightly the wall thickness, so that it can be dispensed with necessary stiffening measures such as in a Ringnutkopplung in the prior art. The skilled artisan will recognize that due to the omission of the annular groove and shortened hydraulic fluid paths are present.

In order to ensure in particular a simple instruction of the hydraulic means in the sickle-like Materialfreistellungen the bucket tappet, it is proposed in concretization of the invention to create a thin-walled sheet metal part inside the housing, in the corresponding channels, starting from one or more passages in the shirt, are formed. Possibly. For example, the channels can also be applied to an inner wall of the housing, so that the thin-walled sheet-metal part can optionally also be represented with a smooth surface.

For circumferential positional assignment of the coupling piston to their sickle-like material exemptions, it is proposed to apply in a ring gap between the two valve train components a simple anti-rotation device such as a pin, a ball or the like.

Likewise, the coupling pistons, in the case of their formation with a flattening for a face-to-face contact with the corresponding counter surface of the sickle-like formation, must be secured against rotation with respect to their bore Optionally, the coupling pistons can also be secured against rotation by a pin projecting into their radial bore. Furthermore, it is provided in concretization of the invention, the inner part thin-walled / pipe-like form, the radial bore with the coupling piston is part of a simple crosspiece. Thus, there is a very inexpensive representable inner element.

Short description of the drawing

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

Figure 1 shows a longitudinal section through a tappet as a switchable valve drive part;

Figure 2 shows a cross section along the section line A-A of Figure 1 and

Figure 3 is rotated by 90 ° relative to Figure 1

Sectional view.

Detailed description of the drawing

Shown is a switchable valve drive part 1, designed here as a bucket tappet.

The valve train part 1 consists of a hollow cylindrical housing 2 which can be arranged in an oscillating manner via its thin-walled shirt 21 in a receptacle of the internal combustion engine. The shirt 21 extends from an outer edge 20 of a ring-like bottom 19 in cam-distant direction. From an inner edge 22 of the bottom 19, a projection 23 is gone. This has a bore 3, in which a contrast axially movable, thin-walled / tubular-like inner element 4 is added. The inner element 4 has no ckenkontakt, so that the switchable valve train part 1 is present as a shutdown.

In a transverse web 38 of the inner element 4 extends a bore 6, which is present here as a radial bore. In this bore 6 are located in the decoupling two coupling piston 7 diametrically opposite. These are urged radially outwards (coupling direction) via the force of a helical compression spring acting against their inner forehead 17 as spring means 18.

On an axial side 12 (here cam side), the coupling piston 7, starting from their radially outer foreheads 11, each provided with a section-wise flattening 13. Figure 1 discloses the coupling state of the valve train part 1, in which the coupling piston 7, partially extended radially outwardly, with a cam surface 9 in the bore 3 of the housing 2 are engaged. This driver surface 9 is represented by an upper flat axial end of a sickle-like material release 14 against which the respective flattening 13 of the coupling piston 7 rests in the coupling case. The material release 14 can be generated, for example, with a retractable into the bore 3 of the housing 2 simple disc milling cutter (see also Figure 2).

As can be seen, the bore 3 of the housing 2 is part of the hollow-cylindrical projection 23 extending from the inner edge 22 of the bottom 19 of the housing 2 in the direction away from the cam.

A return displacement of the coupling piston 7 in the decoupling via above the radially outer forks 11 in the material release 14 conductive hydraulic fluid. For this purpose, the housing 2 has in its interior a largely fitting, thin-walled element 25 as a sheet metal part.

Starting from a passage 26 in the shirt 21 (see Figure 3), the hydraulic fluid is further directed via a shirt side shaped in the element 25 riser 27 in the bottom direction. There is a forwarding radially inwardly via at least one radial passage 28 between the bottom 19 and Radially inside, the hydraulic fluid is further directed downwards via an axial channel 31, which runs between an outer jacket 30 of the attachment 23 and the region of the element 25 located there. In the element 25, a ring channel 32 is formed radially in front of the Materialfreistel- 14, which is in communication with the axial channel 31. Starting from this annular channel 32, a forwarding of the hydraulic fluid via respective crossings 33 takes place directly in the Materialfreistellungen 14 in front of the radially outer forehead 11 of the coupling piston. 7

An annular surface 8 between the components 2, 4 is overlapped by a rotation lock 16. This sits in a recess 34 in the outer jacket 5 of the inner member 4 and is formed as a rolling element. Radially outward, the anti-rotation device 16 (rolling elements) engages in a corresponding longitudinal groove 35 of the bore 3 of the projection 23.

This is designed as a simple securing element as a snap ring which extends in an annular groove 36 on the outer jacket 5 of the inner member 4 and in the region of the coupling piston 7 lies on the flattened portions 13.

List of reference numbers

1) Valve drive part

2) housing 3) bore housing

4) Interior element

5) outer jacket

6) bore coupling piston

7) coupling piston 8) annular surface

9) driving surface

10) lost motion spring means

11) (outer) forehead

12) Axialseite 13) flattening

14) material exemption

15) antirotational

16) antirotational

17) (inner) end 18) spring means

19) Soil

20) outer edge

21) shirt

22) inner edge 23) approach

24) top

25) Element

26) passage

27) riser 28) radial passage

29) Bottom of the ground

30) outer shell

31) axial channel 32) annular channel

33) crossing

34) recess

35) longitudinal groove

36) annular groove

37) vent

38) transverse web

Claims

claims

1. Switchable valve drive part (1), with a hollow cylindrical housing (2), in whose bore (3) a relatively axially movable inner element (4) with its outer casing (5) runs, wherein one of the components [inner element (4) or housing (2)] at least one bore (6) with at least one in the decoupling case extending therein coupling piston (7) is immanent, which bore (6) in the direction of the other component (2, 4) and an annular surface (8) between The components (4, 2) opens, which coupling piston (7) for a coupling case in sections with a cam surface (9) of the other component (2, 4) is engageable and wherein a lost-motion spring means (10) provided is that the components (4, 2) acted on in their Ausschieberichtung away from each other, characterized in that the respective coupling piston (7), starting from the driver surface (9) facing the end (11) on an axial side (12) with a Sectional flattening ( 13), wherein the other component (2, 4), only in the peripheral portion of the adjacent bore (6) with the coupling piston (7) in a component (4, 2), in its bore (3) / on its outer shell ( 5), with a merely sickle-like Materialfreistel- ment (14) is provided, on whose flat Axialstirn the driver surface (9) for engagement of the flattening (13) of the coupling piston (7) is shown for the coupling case and on the one hand, the coupling piston ( 7) relative to the bore (6) and on the other hand, the components (4, 2) to each other with a respective rotation lock (15, 16) are provided.

2. Ventiltriebsteil according to claim 1, characterized in that exactly two coupling piston (7) are provided which extend in the bore formed as a radial bore (6) in the inner element (4) and are diametrically opposite, wherein the coupling piston (7) in their Coupling direction via the force of a spring means (18) acting against its inner forehead (17) how at least one helical compression spring are acted upon, wherein the displacement in decoupling over before their outer forehead (11) in the respective sickle-like material release (14) conductive hydraulic fluid is shown.

3. Valve drive part according to claim 2, characterized in that as switchable valve drive part (1) is provided a bucket tappet with which a ring-like bottom (19) as a cam contact surface having housing (2), over its from the outer edge (20) projecting shirt (21) in a bore of an internal combustion engine is feasible, which bottom (19) is contacted by at least one Großhubnocken, wherein from an inner edge (22) of the bottom (19) projects a hollow cylindrical projection (23), the bore (3) with the inner element (4) guided therein has in which bore (3) the two sickle-like, opposing material reliefs (14) are applied, on the upper sides (24) of which the flat axial bulbs extend as driver surfaces (9) and wherein the inner element (4) on the bottom side, either cam is formed without contact or is provided with a disk-like bottom for a start-up of a low or zero-lift cam.

4. Valve drive part according to claim 3, characterized in that in the interior of the housing (2) a thin-walled element (25) is applied as a sheet metal part, which essentially follows its inner contour, wherein, starting from at least one passage (26) in Shirt (21) of the housing (2), in the element (25) a riser channel (27) for the hydraulic medium is formed with one or more radial passages (28) between a bottom (29) of the bottom (19) and the element (25), wherein at least one axial channel (31) is formed in the element (25), on the outer casing (30) of the projection (23), which is connected to the at least one radial groove (31). passage (28) communicates and continues in the direction away from the floor, which axial channel (31) opens into an annular channel (32) or ring segment channel formed in the element (25) at a height in front of the material reliefs (14), from which one transition (33 ) through the projection (23) leads to the respective sickle-like material release (14).

5. Valve drive part according to claim 1, characterized in that the sickle-like Materialfreistellung (14) with the driver surface (9) by a milling process such as disk milling or by embossing / impressing or turning out is shown.

6. Valve drive part according to claim 1 or 2, characterized in that as rotational security (16) of the components (4, 2) to each other a body such as a ball / a pin is provided, in a recess (34) in the outer jacket (5) of the Inner element (4) or the bore (3) of the housing (2) sits and, the ring surface (8) partially overlapping, in a longitudinal groove (35) of the bore (3) of the housing (2) or the outer sheath (5) of the inside - Elements (4) learns a guide.

7. Valve drive part according to claim 2, characterized in that as a rotation lock (15) of the two coupling piston (7) relative to the bore (6) an annular part such as a snap ring is applied, which is arranged concentrically to the axis of the valve drive part (1) in one Ring groove (36) on the outer casing (5) of the inner element (4) and extends in the bore region on the flats (13) of the coupling piston (7).

8. Valve drive part according to claim 3, characterized in that the inner nenelement (4) is formed substantially thin-walled tube-like, wherein the radially continuous bore (6) for the coupling piston (7) in a dividing the inner member transverse web (38) ,