DE102023102788A1 - Assembly unit for a switchable valve train of a heavy-duty internal combustion engine with an axle piece and a rocker arm group - Google Patents

Abstract

What is proposed is a structural unit (1) for a switchable valve train of a heavy-duty internal combustion engine, with an axle piece (2) and a rocker arm group (3) thereon, which includes a cam rocker arm (4) and a valve rocker arm (5), the cam rocker arm (4) being on a Axle piece long side (6) has a cam contact surface (8) and the valve rocker arm (5) has a valve contact surface (11) on another axle piece long side (9), with longitudinal center planes of the two levers (4, 5) coinciding and the cam rocker arm (4) the valve rocker arm (5 ) in the area of the axle piece (6) with longitudinal walls (12) that run out towards the other longitudinal side of the axle piece (9) and runs at least indirectly on the axle piece (2) via eyes (13), which valve rocker arm (5) on one side Axle piece longitudinal side (6) ends with an extension (14) housed by the longitudinal walls (12) of the cam rocker arm (4), with coupling slide means (16) which can be displaced via an e-actuator (15) running in the rocker arm group (3) and whereby as a cam return spring ( 17) a helical compression spring is installed upright between the two levers (4, 5).

Description

The invention relates to a structural unit for a switchable valve train of a heavy-duty internal combustion engine, with an axle piece and at least one rocker arm group thereon, which comprises a cam rocker arm and a valve rocker arm, which can be pivoted relative to one another, each on the axle piece, the cam rocker arm being on a longitudinal side of the axle piece at its outer longitudinal end Cam contact surface and the valve rocker arm have an at least indirect valve contact surface on an opposite longitudinal side of the axle piece at its outer longitudinal end, a cam return spring being clamped between the levers and a coupling slide group running on one longitudinal side of the axle piece in the rocker arm group, which can be at least indirectly actuated by an e-actuator.

A “heavy-duty internal combustion engine” is a machine that is used in particular to drive a truck, transporter, light transporter, agricultural implement, ship, mining or construction site equipment, etc.

The DE 10 2020 113 219 A1 shows in 1 a valve train for a heavy-duty internal combustion engine with an axle piece and two groups of rocker arms on it. Each group has a cam rocker arm, to which a wall-to-wall valve rocker arm is assigned in sections. A torsion leg spring is provided as the cam return spring, which encloses the axle piece with its winding package and is directly adjacent to the cam rocker arm.

The task is to propose a structural unit that is simple and compact and has excellent rigidity.

This task is solved by the features of claim 1. What is therefore proposed is a structural unit for a switchable valve train of a heavy-duty internal combustion engine, with an axle piece and at least one rocker arm group thereon, which comprises a cam rocker arm and a valve rocker arm, which can be pivoted relative to one another, each on the axle piece, the cam rocker arm being on a longitudinal side of the axle piece at its outer longitudinal end Cam contact surface and the valve rocker arm on another longitudinal side of the axle piece have an at least indirect valve contact surface at its outer longitudinal end, with longitudinal center planes of the two levers coinciding and the cam rocker arm surrounds the valve rocker arm in the area of the axle piece with longitudinal walls that taper like a fork in the direction of the other longitudinal side of the axle piece and at least have eyes in these runs indirectly on the axle piece, which valve rocker arm ends on the one longitudinal side of the axle piece with an extension housed by the longitudinal walls of the cam rocker arm, with coupling slide means that can be displaced via an e-actuator running in the rocker arm group and at least one helical compression spring as the cam return spring between the two levers on the long side of the axle piece is installed upright, which is clamped between a lower face of the approach of the valve rocker arm and an upper face of a crossbar connecting the longitudinal walls of the cam rocker arm on the underside.

The nested structure of the two levers with an integrated cam return spring results in a rigid structural unit that requires comparatively few components, is tip-proof and light.

The at least one helical compression spring as a cam return spring is easy to install and does not require any external installation space. If necessary, the use of a helical compression spring package is also possible. A displacement of the coupling slide means is provided in at least one direction via the e-actuator, which can be installed, for example, on the cylinder head, the rocker arm group or a carrier for this purpose. The e-actuator can also only act indirectly and, for example, actuate a central push bar with spring tongues on it, one of which is assigned to a coupling slide means of a rocker arm group. It is also conceivable to install the upright helical compression spring on the other long side of the axle piece on the valve side.

A simple measure for holding and guiding the cam return spring, which is also referred to as a lost motion spring, is the subject of a dependent claim. Accordingly, this is guided in a pocket which, for example, starts from the top face of the crossbar of the cam rocker arm. This also makes the assembly process easier. The pocket is preferably connected in one piece to the crossbar, which in turn is preferably a one-piece component of the cam rocker arm.

According to a further specification of the invention, the longitudinal walls of the cam rocker arm are connected on their upper sides via a saddle (cross strut), which is preferably also connected in one piece. This measure stiffens the cam rocker arm. It is particularly preferred here if an underside of the saddle slides on an upper face of the extension of the valve rocker arm, which helps guide the levers relative to one another. At the same time, in this area, stop measures for the two levers in the direction of rotation relative to each other via communicating transverse faces are proposed.

The cam rocker arm can run directly on the axle piece via eyes in its longitudinal walls. However, an expedient solution is proposed in which pipe extensions respectively protrude from both outer walls of the valve rocker arm, via which the valve rocker arm lies on the axle piece together with its bore between the pipe extensions and on which pipe extensions the cam rocker arm is slidably mounted via its eyes. Due to the bearing gap being on the larger diameter, the bearing load is reduced.

A further development of the invention relates to a design of the coupling slide means. These should therefore run transversely to the rocker arm group and consist of a package of a pusher in one of the longitudinal walls of the cam rocker arm and a continuous piston in the valve rocker arm. The pusher can be moved inwards by the e-actuator on its “free” outer face. Pushers and pistons can run in separate rings or the like, which are included in the levers. Another ring can sit in the further longitudinal wall of the cam rocker arm, which is opposite the longitudinal wall with the pusher. The further ring serves to engage the piston in sections when it is displaced in the coupling direction.

In general, the idea is to shift the coupling slide means in one direction (coupling or decoupling direction) via the e-actuator and to shift it back via compression spring force or also via an e-actuator. A possible at least indirect valve contact surface in the valve rocker arm is, for example, a hydraulic insert element or an adjusting screw. The valve rocker arm preferably acts on a bridge.

• • 1 zeigt eine räumliche Ansicht der Kipphebelgruppe;
• • 2 zeigt einen Längsschnitt durch die Kipphebelgruppe;
• • 3 zeigt die Kipphebelgruppe in einer Explosivdarstellung und
• • 4 zeigt als Einzelheit eine Ansicht der Koppelschiebermittel.

About the drawing:

• • 1 shows a spatial view of the rocker arm group;
• • 2 shows a longitudinal section through the rocker arm group;
• • 3 shows the rocker arm group in an exploded view and
• • 4 shows a view of the coupling slide means as a detail.

The 1 - 3 show a structural unit 1 for a switchable valve train of a heavy-duty internal combustion engine. The unit 1 includes, as well 1 shows, an axle piece 2 and a rocker arm group 3 on it. The latter consists of a cam rocker arm 4 visible on the right and a valve rocker arm 5 shown on the left. Both levers 4, 5 run on the axle piece 2 so that they can pivot relative to one another. Pipe extensions 29 protrude from the outer walls 28 of the valve rocker arm 5, over which it, together with its in between located hole 37, on which axle piece 2 is mounted. The cam rocker arm 4 is mounted on the pipe extensions 29 via bore-like eyes 13 in its longitudinal walls 12.

The cam rocker arm 4 has a cam contact surface 8 on a longitudinal side 6 of the axle piece shown here on the right, at its outer longitudinal end 7. The valve rocker arm 5 has an indirect valve contact surface 11 on another longitudinal side 9 of the axle piece, at its outer longitudinal end 10, which acts as a hydraulic play compensation element 36 ( Plug-in element). A contact is provided on a bridge for the simultaneous actuation of two gas exchange valves such as exhaust valves.

It is best recognized in 1 that the longitudinal center planes of the two levers 4, 5 coincide, the two levers 4, 5 are, so to speak, “plugged into one another” in sections. The cam rocker arm 4 encloses the valve rocker arm 5 on the axle piece 6 with its longitudinal walls 12, which extend like a fork in the direction of the other longitudinal side of the axle piece 9. At the same time, the valve rocker arm 5 ends on one of the longitudinal sides of the axle piece 6 with an extension 14 encompassed by the longitudinal walls 12 of the cam rocker arm 4, which also consists of the 2 , 3 emerges.

A cam return spring 17 in the form of a helical compression spring is installed between the levers 4, 5. This stands “upright” on one of the longitudinal sides 6 of the axle piece and is clamped between a lower end face 18 of the aforementioned extension 14 of the valve rocker arm 5 and an upper end face 19 of a crossbar 21 connecting the longitudinal walls 12 of the cam rocker arm 4 on the underside 20 of the latter. A pocket 22 extends from this crossbar 21 (see Fig. 2 ), in which the cam return spring 17 stands in sections.

The longitudinal walls 12 of the cam rocker arm 4 are connected on their upper sides 22a via a saddle 23, the underside 24 of which is guided on an upper face 25 of the extension 14 of the valve rocker arm 5. The contact surfaces are designed to be complementary. At the same time they reveal 1 , 2 that the saddle 23 has a transverse face 26 facing the valve rocker arm 5, which faces a transverse face 27 of the valve rocker arm 5. This creates a simple rotation stop of the two levers 4, 5 relative to each other in their decoupling mode produced via the coupling slide means 16.

Furthermore, the rocker arm group 3 has the coupling slide means running transversely therein 16 on (see esp. 4 ). These consist of a piston 31, which is guided in a separate ring element 38, which sits in a transverse bore 30 in the shoulder 14 of the valve rocker arm 5. The piston 31 runs axially completely over the length of the transverse bore 30 and thus also of the ring element 38. In addition, a pusher 33 sits in a guide ring 39. The latter unit is accommodated in a transverse bore 32 of one of the longitudinal walls 12 of the cam rocker arm 4 and is aligned with the aforementioned unit consisting of ring element 38 and piston 31 when the cam base circle passes through. The pusher 33 is on its outer face 34 an e-actuator 15 can be acted upon, which is indicated by the arrow in 4 is indicated. In addition, another transverse hole is applied in the other longitudinal wall 12 of the cam rocker arm 4, which is not shown in the drawing. A further guide ring 40 sits in this transverse bore, into which the piston 31 moves in the coupling mode (coupling of the two levers 4, 5 with one another) with an area 35 remote from the actuator.

The piston 31 and thus also the pusher 33 are reset when the e-actuator 15 is deactivated or switched to low current, as is usual when the cam base circuit passes through, here via the force of a return spring 41 surrounding the piston 31 in the ring element 38 and acting on it.

List of reference numbers

1)

structural unit

2)

axle piece

3)

Rocker arm group

4)

Cam rocker arm, lever

5)

Valve rocker arm, lever

6)

Axle piece long side

7)

Longitudinal end

8th)

Cam contact surface

9)

Axle piece long side

10)

Longitudinal end

11)

Valve contact surface

12)

Longitudinal wall

13)

Eye

14)

Approach

15)

e-actuator

16)

Coupling slider medium

17)

Cam return spring

18)

Underforehead

19)

upper forehead

20)

bottom

21)

cross bar

22)

Bag

22a

Top

23)

saddle

24)

bottom

25)

upper forehead

26)

Transverse forehead

27)

Transverse forehead

28)

external wall

29)

pipe attachment

30)

Cross hole

31)

Pistons

32)

Cross hole

33)

Pusher

34)

Outer forehead

35)

Area

36)

Backlash compensation element

37)

drilling

38)

Ring element

39)

Guide ring

40)

Guide ring

41)

return spring

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely 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.

Cited patent literature

• DE 102020113219 A1 [0003]

Claims (7)

Structural unit (1) for a switchable valve train of a heavy-duty internal combustion engine, with an axle piece (2) and at least one rocker arm group (3) thereon, which has a cam rocker arm (4) and a valve rocker arm (5), which can be pivoted relative to one another, each on the axle piece (2). , wherein the cam rocker arm (4) on one axle piece longitudinal side (6) has a cam contact surface (8) at its outer longitudinal end (7) and the valve rocker arm (5) on another axle piece longitudinal side (9) has an at least indirect one at its outer longitudinal end (10). Have valve contact surface (11), the longitudinal center planes of the two levers (4, 5) coinciding and the cam rocker arm (4) the valve rocker arm (5) in the area of the axle piece (6) with longitudinal walls (12) tapering out like a fork in the direction of the other longitudinal side of the axle piece (9). and runs at least indirectly on the axle piece (2) via eyes (13), which valve rocker arm (5) on one longitudinal side (6) of the axle piece has an extension (14) housed by the longitudinal walls (12) of the cam rocker arm (4). ends, wherein in the rocker arm group (3) via an e-actuator (15) displaceable coupling slide means (16) run and at least one helical compression spring as a cam return spring (17) is upright between the two levers (4, 5) on one longitudinal side of the axle piece (6). is installed, which is clamped between a lower face (18) of the extension (14) of the valve rocker arm (5) and an upper face (19) of a crossbar (21) connecting the longitudinal walls (12) of the cam rocker arm (4) to the underside (20). . structural unit Claim 1 , wherein the cam return spring (17) is guided in a pocket (22) which extends from the lower face (18) of the extension (14) of the valve rocker arm (5) and / or the upper face (19) of the crossbar (21) of the cam rocker arm (4 ) goes out. structural unit Claim 1 , wherein the longitudinal walls (12) of the cam rocker arm (4) are connected on their upper sides (22a) via a saddle (23), the underside (24) of which lies directly above an upper face (25) of the extension (14) of the valve rocker arm (5). , whereby a rotation stop of the two levers (4, 5) in their decoupling mode established via the coupling slide means (16) [maximum spread position of the two levers (4 , 5) from each other]. structural unit Claim 1 , wherein the valve rocker arm (5) is mounted on the axle piece (2) via pipe extensions (29) projecting from its outer walls (28). structural unit Claim 4 , wherein the cam rocker arm (4) encompasses the tube extensions (29) of the valve rocker arm (4) with the eyes (13) of its longitudinal walls (12). structural unit Claim 1 , whereby the coupling slide means (16) run transversely to the rocker arm group (3). structural unit Claim 4 , whereby, to represent the coupling slide means (16), a continuous piston (31) sits at least indirectly in a transverse bore (30) of the extension (14) of the valve rocker arm (5), which in a transverse bore (32) of one of the longitudinal walls (12) of the cam rocker arm (4) is adjacent to a pusher (33) which is at least indirectly accommodated there and which can be acted upon by the e-actuator (15) on its outer face (34), with another one in the other longitudinal wall (12) of the cam rocker arm (4). , to which a transverse bore (32) of the longitudinal wall (12) is aligned for a sectional and at least indirect engagement of the piston (31) with its area (35) remote from the actuator.

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