CN116658269A

CN116658269A - Combined unit for switchable valve actuation of a heavy-duty internal combustion engine

Info

Publication number: CN116658269A
Application number: CN202210152589.1A
Authority: CN
Inventors: 阳荣
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Holding China Co Ltd
Priority date: 2022-02-18
Filing date: 2022-02-18
Publication date: 2023-08-29

Abstract

The invention relates to a combined unit for a switchable valve train of a heavy-duty internal combustion engine, comprising a shaft and a rocker arm group thereon, which comprises a cam rocker arm and a valve rocker arm, each rocker arm being pivotally movable on the shaft relative to the other. The cam rocker arm has a cam contact surface on one shaft longitudinal side of its outer longitudinal end and a valve contact surface on the other shaft longitudinal side of its outer longitudinal end. Wherein the longitudinal centre planes of the two levers coincide, the cam rocker encloses the valve rocker in the region of the shaft element, and a tubular projection extends outwardly from each longitudinal wall. By means of these tubular projections, the cam rocker arm is mounted on the shaft. Wherein the valve rocker is located on one longitudinal side of the shaft element, and an extension is provided between the longitudinal walls of the cam rocker, wherein the laterally arranged coupling slide means are operated, which can be displaced in the longitudinal direction by means of an electromagnetic drive.

Description

Combined unit for switchable valve actuation of a heavy-duty internal combustion engine

Technical Field

The invention relates to the technical field of internal combustion engines. In particular, the invention relates to a combined unit for switchable valve actuation of a heavy-duty internal combustion engine.

Background

The term "heavy-duty internal combustion engine" is understood to mean a machine which is used in particular for driving trucks, transport vehicles, light transport vehicles, agricultural tools, ships, mining or construction tools and the like.

DE 10 2020 113 219 A1 shows a valve train for a heavy-duty internal combustion engine in fig. 1, which has a shaft element on which two rocker arm groups run. Each group has a cam rocker arm, one valve rocker arm being assigned to its wall-to-wall portion. The torsion bar spring as a cam return spring surrounds the shaft element with its coil pack and is directly adjacent to the cam rocker arm.

Disclosure of Invention

The technical problem to be solved by the present invention is therefore to provide a combined unit as described above, which is simple in structure and has good rigidity.

According to the invention, this object is achieved in that the longitudinal center planes of the levers coincide, the longitudinal cam arm walls enclosing the valve rocker in the region of the shaft element, wherein a tubular projection protrudes outwards from each longitudinal wall. The cam arm is mounted on the shaft member by tubular projections therein, at least one of which is enclosed by a coil of a rotary leg spring, and the valve arm is located in one longitudinal direction of the shaft member with its distal extension located between the longitudinal walls of the cam arm.

Because of the nested construction of the rocker arm set, the levers of which are "behind one another", a particularly strong construction is proposed which is capable of withstanding the high loads in a valve train of a heavy-duty internal combustion engine and which is relatively simple in construction. The surface load is also reduced by the bearings of the cam rocker arm extending through the lateral tube on the shaft element, good bearing conditions being achieved during operation. Furthermore, there is a simple possibility to mount at least one torsion bar spring together with its coil package, which advantageously comprises a shaft element. In the best case, the two levers of the rocker arm set can thus be connected to the shaft element with preloaded torsion bar springs.

It is obvious that the proposed valve train can also be used for internal combustion engines, for example in the field of passenger vehicles.

According to an advantageous further development of the invention, it is proposed that the longitudinal wall of the cam rocker is braced in the region of the shaft element by means of a stiffening rod. The reinforcing bars are advantageously located on the upper side of the rocker arm set and are connected in one piece or as separate connected parts. The reinforcement bar is composed of parts of the valve rocker together with parts of the longitudinal wall.

Further dependent claims define advantageous stops between the cam rocker arm and the valve rocker arm to achieve its disengaged mode (valve deactivation).

Thus, on the one hand, a laterally arranged stop profile is provided on the underside of the rocker arm assembly, such as a convex surface/die or the like, which communicate with one another. In the release mode, these ensure an aligned position of the coupling holes of the coupling slide, which is created by the force of the torsion leg springs.

On the other hand, a similar stop profile is also proposed on the upper side of the rocker arm set. This may prevent the cam rocker arm from overshooting in the unhooking mode, which may lead to overload of at least one torsion leg spring. Advantageously, a leg spring is operated on each tubular projection of the cam rocker arm as a cam return spring.

Another dependent claim relates to the practical design of the coupling slide to run transversely in one longitudinal direction of the shaft. The slider assembly comprises two pistons located in tandem in respective bores of the two rocker arms. The piston in the rocker arm hole on the cam side has a contact surface on the outside. The electronic actuator may act directly on this surface. In addition, an indirect contact, such as by an actuation finger, spring tongue or deflection mechanism, is also contemplated and provided. It is also possible to mount the electronic actuator directly on the longitudinal wall of the cam rocker arm.

For example, a valve rocker arm may act on one bridge for simultaneously actuating two gas exchange valves that act in the same way. However, it is also possible to drive a gas exchange valve or a tappet directly. Furthermore, the valve rocker may be equipped with a hydraulic insert for adjusting the valve clearance at its contact point.

Drawings

The invention is further described below with reference to the accompanying drawings. Like reference numerals in the drawings denote functionally identical elements. Wherein:

figure 1 shows a three-dimensional view of the rocker arm set.

Figure 2 shows a longitudinal section through the rocker arm set.

Figure 3 shows a cross section through the rocker arm set in the coupling slide part, and

figure 4 shows a cross-section of the rocker arm set in the axial segment.

Detailed Description

Specific embodiments of a hydraulic lash adjuster according to the present invention will be described below with reference to the accompanying drawings. The following detailed description and the accompanying drawings are provided to illustrate the principles of the invention and not to limit the invention to the preferred embodiments described, the scope of which is defined by the claims.

According to an embodiment of the present invention, a combination unit for switchable valve actuation of a heavy duty internal combustion engine is provided. Fig. 1 and 2 show a combined unit 1 for a switchable valve train of a heavy-duty internal combustion engine. The combined unit 1 comprises a shaft element 2, as shown in fig. 1, on which a rocker arm set 3 is provided. The shaft element 2 may also be a shaft extending through the cylinder head, on which a plurality of rocker arm sets 3 are provided.

The rocker arm set 3 comprises a cam rocker arm 4, which is located substantially on a longitudinal side 6 of the shaft element. Also nested in sections with the cam rocker arm 4 is a valve rocker arm 5, which is located mainly on the other longitudinal side 9 of the shaft element 2. Both levers 4,5 can be moved relatively on the shaft 2 (see also fig. 4).

The cam rocker 4 has a cam contact surface 8 in the form of a roller mounted on a needle bearing at the outer longitudinal end 7 of the longitudinal side 6 of the shaft (see fig. 2). The valve rocker 5 has a valve contact surface 11 on the other longitudinal side 9 of the shaft element 2 at its outer longitudinal end 10. The valve contact surface 11 is not shown as being formed on an interposed hydraulic lash compensation element. The valve rocker 5 can, for example, act on a bridge for simultaneously actuating several gas exchange valves or directly on the gas exchange valves in the opening direction via the valve contact surface 11.

Briefly, the levers 4,5 "one behind the other". Their longitudinal central planes are aligned with each other. Fig. 1 shows that the cam rocker 4 encloses the valve rocker 5 in the region of the shaft element 2, the longitudinal wall 12 of which is integrally connected to the reinforcing rod 21 on the upper side 29 of the rocker group 3. A tubular projection 13 extends from the outside of each longitudinal wall 12 of the rocker arm 4. The cam rocker 4 is slidably mounted on the shaft 2 by means of these tubular projections 13. The valve rocker 5 is located on one longitudinal side 6 of the shaft, with its terminal extension 18 located between the longitudinal walls 12 of the cam rocker 4.

Both tubular projections 13 are respectively surrounded by coil packs 14 of a torsion leg spring 15 as a cam return spring (lost motion spring). One end leg 16 of which is supported on the cam rocker arm 4 and the other end leg 17 of which is supported on the valve rocker arm 5.

On one longitudinal side of the shaft element 2, a laterally arranged coupling slide 19 runs in a lateral bore 22, 23 of the rocker arm 4,5 (see fig. 3). The transverse bore 23 of the valve rocker 5 is located at its end extension 18. The coupling slide 19 is a piston 24, 25. The "inner" piston 25 passes completely through the transverse bore 23 of the valve rocker 5 in the shown separated mode (cam base circle passage) of the two levers 4, 5. The piston 24 in the transverse bore 22 of the longitudinal wall 12 of the cam rocker 4 shown on the left in fig. 3 is located in front of the end face 32 of the piston 25 in the valve rocker 5. Piston 24 has a sensing surface 34 on its outer side 33 for at least indirect engagement with an electronic actuator (see arrows in fig. 3, see fig. 1). Feedback of actuator force is achieved by unspecified pressure spring means.

In the split mode, the valve rocker 5 is "empty" on the stationary cam rocker 5 during the cam stroke after the passage of the cam base circle. An over-rotation protection is provided by which the maximally extended position of the rocker arms 4,5 is limited to each other against the force of the two leg-torsion springs 15. As shown in fig. 2, on the cam rocker arm 4, there is a lateral stop end 30 on the upper side 29 of the rocker arm set 3. In contrast, in the direction of rotation, the valve rocker 5 has a stop surface 31, which also extends transversely.

Measures are also provided between the cam rocker arm 4 and the valve rocker arm 5 to limit the backward swing in the separation mode (see fig. 2). The rearward pivotal movement of the cam side down is accomplished by the force of the two torsion leg springs 15. In this position, the levers 4,5 have a maximum bending position with respect to each other and the transverse holes 22, 23 are aligned with each other so that the combination of pistons 24, 25 can be moved in segments at the interface between the levers 4,5 on the electronic actuator (coupling box). For this purpose, the valve rocker 5 has a laterally extending projection 27 on the bottom face 26 of the rocker arm assembly 3, the contour of which is opposite to the complementary contour 28 on the cam rocker 4.

While possible embodiments are exemplarily described in the above description, it should be understood that there are numerous variations of the embodiments still through all known and furthermore easily conceivable combinations of technical features and embodiments by the skilled person. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. The technical teaching for converting at least one exemplary embodiment is provided more in the foregoing description to the skilled person, wherein various changes may be made without departing from the scope of the claims, in particular with regard to the function and structure of the components.

Reference numeral table

1. Combined unit

2. Shaft element

3. Rocker arm group

4. Cam rocker arm, lever

5. Valve rocker, lever

6. Longitudinal side

7. Lateral longitudinal end

8. Cam contact surface

9. Longitudinal side

10. Lateral longitudinal end

11. Valve contact surface

12. Longitudinal wall

13. Tubular projection

14. Coil package

15. Torsion leg spring

16. End leg

17. End leg

18. Extension part

19. Coupling sliding device

21. Reinforcing rod

22. Transverse hole

23. Transverse hole

24. Piston

25. Piston

26. Bottom surface

27. Protruding part

28. Complementary profiles

29. Upper side of

30. Stop end

31. Stop surface

32. End face

33. Outside is provided with

34. Induction surface

Claims

1. A combined unit (1) for switchable valve actuation of a heavy-duty internal combustion engine, having a shaft (2) and at least one rocker arm group (3) thereon, which rocker arm group comprises a cam rocker arm (4) and a valve rocker arm (5), each rocker arm being pivotally movable on the shaft (2) relative to the other rocker arm, wherein the cam rocker arm (4) has a cam contact surface (8) on one shaft longitudinal side (6) of its outer longitudinal end (7), the valve rocker arm (5) has an at least indirect valve contact surface (11) on the other shaft longitudinal side (9) of its outer longitudinal end (10), characterized in that the longitudinal centre planes of the two rocker arms (4, 5) coincide, the cam rocker arm (4) encloses the valve rocker arm (5) with its longitudinal wall (12) in the region of the shaft (2) and protrudes outwards from each longitudinal wall (12) by means of a tubular projection (13), the cam rocker arm (4) being mounted on the shaft (2) with a cam contact surface (8), at least one leg (13) being surrounded by a tubular spring (15) on the other leg (15) which is surrounded by a rocker arm leg (15) as a return spring (17) on the other leg (15), the valve rocker (5) is located on a longitudinal side (6) of the shaft, an extension (18) is provided between the longitudinal walls (12) of the cam rocker (4), and a laterally arranged coupling slide (19) is operated in this case, which can be displaced at least indirectly in a longitudinal direction by means of an electromagnetic drive.

2. A combination unit according to claim 1, characterized in that the longitudinal inner end (20) of the longitudinal wall (12) of the cam rocker (4) at its shaft (2) is connected by a stiffening rod (21) which at least partly encloses the extension (18) of the valve rocker (5).

3. A combination unit according to claim 1, characterized in that in order to represent a rearward pivot position in the separation mode between the cam rocker (4) and the valve rocker (5), in which rearward pivot position a transverse bore (22, 23) is provided for the coupling element formed as at least one piston (24), said transverse bores (22, 23) being aligned with each other [ maximum folded position of the levers (4, 5) relative to each other ] in the rocker group (3), in the case of one rocker (4), a transversely extending projection (27) is seated on the bottom surface (26) of the rocker group (3) and matches a complementary contour (28).

4. A combination unit according to claim 1 or 3, characterized in that in order to represent over-rotation protection in the separated mode of the cam rocker arms (4) by the valve rocker arms (5) [ maximum open position of the rocker arms (4, 5) ] in the case of one rocker arm (4) a laterally extending stop end (30) is provided at the upper side (29) of the rocker arm set (3), which stop end (30) is opposite to the laterally extending stop surface (31) of the other rocker arm (5).

5. The combination unit according to claim 1, characterized in that the coupling slide (19) of the rocker arm set (3) consists of at least two pistons (25, 24), wherein the first piston (25) in the separated mode passes completely through the transverse bore (23) of the valve rocker arm (5), the second piston (24) is located in front of it and in front of an end face (32) in the transverse bore (22) of a longitudinal wall (12) of the cam rocker arm (4), the second piston (24) having on its outer side (33) an inductive surface (34) for at least indirect engagement with the transmission.