Assembly for a switchable valve train of a heavy duty internal combustion engine with a shaft member and at least one rocker arm group

Abstract

The invention relates to an assembly (1) for a switchable valve train of a heavy duty internal combustion engine, having a shaft (2) and a rocker arm group (3) thereon, which comprises a cam rocker arm (4) and a valve rocker arm (5), wherein the longitudinal centre planes of the two rocker arms (4, 5) coincide. The valve rocker arm (5) ends in the longitudinal direction of the shaft (6) with an end extension (12) so as to be received between longitudinal walls (13) of the cam rocker arm (4), which longitudinal walls (13) are connected by a web (14) which rests on the end extension (12), wherein a coupling slide group (15) extends in the end extension (12). A first slide (17) is accommodated in its lateral bore (16), the outer side (18) of which can be acted upon at least indirectly by an electronic actuator, the lateral bore (16) being traversed by a bore (18) which runs in the upward direction of the valve rocker arm (5), a second slide (19) being present as a further component of the coupling slide group (15). It is in translational connection with the first slide (17) by means of a ramp device (20), which slide can be moved inwardly by the electronic actuator in the coupling mode, so that the latter engages the second slide (19) in segmental engagement with a drive surface (21) of the web (14) of the cam rocker arm (5).

Description

TECHNICAL FIELD

[0001] The invention relates to an assembly for a switchable valve drive of a heavy-duty internal combustion engine, having a shaft and at least one rocker set thereon, which rocker set comprises a cam rocker and a valve rocker, each of which is movable on the shaft relative to the other. Wherein the cam rocker has a cam contact surface at its outer longitudinal end on one longitudinal side of the shaft, and the valve rocker has at least one indirect valve contact surface at its outer longitudinal end on the other longitudinal side of the shaft, wherein a cam return spring is clamped between the rockers, and a coupling slider set extends in the rocker set on one longitudinal side of the shaft and can be indirectly driven at least by an electric push rod. BACKGROUND

[0002] By a so-called "heavy-duty internal combustion engine" is meant a machine which is used in particular to drive trucks, transporters, light transporters, agricultural tools, ships, mining or construction site tools, etc.

[0003] DE 10 2020 113 219 A1 shows in Figure 1 a valve train for a heavy-duty internal combustion engine, which has a shaft on which two rocker sets run. Each set has a cam rocker, to which a valve rocker is assigned on the part of the longitudinal wall. A torsion spring as a cam return spring surrounds the shaft with its coil. SUMMARY

[0004] It is an object of the invention to provide an assembly as described above, which is simple in construction and has a good rigidity.

[0005] According to the invention, this task is solved by arranging the rockers in such a way that their longitudinal center planes coincide, whereby the valve rocker ends at one longitudinal end of the shaft, has an end extension and is attached between the longitudinal walls of the cam rocker. Wherein the longitudinal walls are connected by a web which at least partially covers the end extension, wherein a coupling slider set runs in the end extension, comprising a first slider which is accommodated in a transverse bore of the end extension, the outside of which can be acted on at least indirectly by an electronic actuator. Wherein the transverse bore intersects a bore which extends in the upward direction of the valve rocker, a second slider as a further component of the coupling slider set, which is in translational connection with the first slider by means of a ramp device, can be moved inward by the electronic actuator in such a way as to achieve a coupling mode. Wherein for a decoupling mode, the first slider can be moved back by actuating means in the event of deactivation of the electronic actuator, so that the latter releases the second slider from the coupling mode.

[0006] Due to the nested structure of the rocker arm assembly, the rocker arms are arranged "one behind the other", so that a particularly robust structure is proposed, which is very suitable for high loads in heavy-duty internal combustion engine valve trains and is also comparatively simple. The webs bridging the longitudinal walls of the cam rockers can be joined in one or more parts, which also has a strengthening effect on the overall structure.

[0007] As a ramp means for the driving connection of the two sliders in the end connection, there is a coupling groove on one of the sliders, and a guide pin projects from the other slider. Alternatively, interacting wedge surfaces or the like are also possible. The second slider, which is intended to be actually connected to the web of the cam rocker, runs in its bore in the upward direction of the valve rocker. This bore can also have a slanted course in the rocker, so that it is not clearly vertical. It is preferred that the web is located above the rocker assembly. However, it is also possible to run along the bottom of the rocker. In the coupling, the coupling measures provide a uniform force input to the rocker assembly, so that it is not tilted.

[0008] The transverse bore and / or the bore extending upward at the end connection of the valve rocker are proposed as through bores, which simplifies their manufacture. However, at least the transverse bore can also be a blind bore, so that the actuator for the first slide, preferably in the form of a compression spring, is simply supported at one end.

[0009] Due to the further development according to the invention, the cam rocker is supported by a lateral tube on the shaft element, while reducing the surface load and achieving good support conditions during operation. In addition, at least one torsion spring with its coil combination, which advantageously comprises the respective shaft element, creates a simple installation possibility. The end feet of similar torsion springs can also be connected to each other, for example those acting on the valve rocker, so that we can speak of a torsion spring with two axially spaced coil packs. In addition, a return spring supported on the cylinder head can be applied on the cam rocker.

[0010] In a further development of the invention, it is also proposed that the contact surface of the second slider with the driving surface of the rod on the cam rocker is in the form of a pawl or similar to a pawl. In the coupled state, the pawl thus engages with the flat on the complementary surface of the web. In this case, a lower component load is to be expected. If necessary, at least one contact element can also be chamfered in the "insert region", so that edge wear is minimized. The driving surface in the rod is formed at the window in the rod. Alternatively, a protrusion or the like can also be considered.

[0011] The proposed valve train can also be used in internal combustion engines in the passenger car sector, for example. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1is a perspective view of a rocker assembly according to the invention.

[0013] Figure 2 is a longitudinal section through the space portion of the rocker assembly in one longitudinal direction of the shaft member.

[0014] Figure 3 is a space cross-section through the rocker assembly in the longitudinal section of the lateral bore of the rocker arm end boss.

[0015] Figure 4 is a cross-section through the rocker assembly in the longitudinal direction of the shaft member. DETAILED DESCRIPTION

[0016] In the following, embodiments of the invention will be described with reference to the drawing. The following detailed description and drawings are used to illustrate the principles of the invention by way of example, the invention not being limited to the preferred embodiments described, the scope of the invention being defined by the claims. The invention will now be described in detail with reference to the exemplary embodiments, some of which are illustrated in the drawings. The following description refers to the accompanying drawings that show, by way of example, specific embodiments in which the principles of the invention are utilized. Like numbers in the figures refer to like elements or features. The schemes described in the following exemplary embodiments are not meant to represent all schemes in which the invention resides. Rather, these schemes are merely examples of systems and methods of various aspects of the invention involved in the claims appended hereto.

[0017] Figure 1 An assembly 1 for a switchable valve train of a heavy duty internal combustion engine is shown. The assembly 1 comprises a shaft member 2, in Figure 4 , and a rocker assembly 3 thereon. The latter consists of a cam rocker 4, shown on the left in Figure 1 , and a valve rocker 5, shown on the right. Both rockers 4, 5 run on the shaft member 2, so that they can be rotated relative to each other.

[0018] The cam rocker 4 has a cam contact face 8 in its outer longitudinal direction 7, which lies in the longitudinal direction 6 of the shaft member. The valve rocker 5 has a valve contact face 11 in its outer longitudinal direction 10, which lies in the other longitudinal direction 9 of the shaft member, here on the right side of the shaft member 2. This can be in the form of a hydraulic insert element, which acts on the valve bridge in the opening direction, for example by means of a so-called "elephant foot".

[0019] The rockers 4, 5 are arranged one behind the other. It can be seen (see Figure 1 , 2 ) that the valve rocker 5 ends in one longitudinal side of the shaft member 6 (left side) with an end extension 12. In this case, it is accommodated in sections by the longitudinal wall 13 of the cam rocker 4. Furthermore, it can be seen from Figures 1-3 that the longitudinal wall 13 of the cam rocker 4 is connected by a web 14, which covers the end extension 12.

[0020] A tubular projection 27 is connected to each longitudinal wall 13 of the cam follower 4 and projects outwardly. The cam follower 4 is slidably mounted on the shaft 2 by means of these tubular projections 27 (see Figure 1 , 4 ). Each tubular projection 27 is surrounded by a coil 28 of a cam return spring 29 in the form of a rotating leg spring. One end leg 31 is supported on the cam follower 4 and the other end leg 32 is supported on the valve rocker 5. Thus, two cam return springs 29 are mounted.

[0021] A coupling slider group 15 is guided in the end extension 12 of the valve rocker 5 (see Figure 2 , 3 ). A first slider 17 is located in a transverse bore 16 of the end extension 12, which slider projects into an arcuate slot 36 of the longitudinal walls 13 of the cam follower 4, one outer side 18 of which can be acted on directly or indirectly by an electronic actuator. The transverse bore 16 is penetrated by an upwardly extending bore 30 of the valve rocker 5, and a second slider 19 is the other component of the coupling slider group 15. Both bores 16, 30 are through bores.

[0022] The coupling slider group 15 is connected in translation by means of a ramp device 20. More precisely, the first slider 17 has a connecting slot 23 in the transverse bore, and a guide pin 24 of the second slider 19 engages in the upwardly extending bore 30.

[0023] As shown in Figure 2 , the web 14 of the cam follower 4 has a window 35, and the drive face 21 is a contact face 33 of the second slider 19. The contact face 33 here is a flat 34 on the claw-like end face of the second slider 19.

[0024] Figures 1 to 3 The coupling mode [full cam lift transmission] of the rocker assembly 3 is shown. This mode is achieved by energizing the electronic actuator, which results in an inward displacement of the first slider 17. Here, the second slider 19 is engaged with its flat 34 on the claw-like end face in the window 35 in the web 14 with the complementary drive face 21. For the decoupling mode [zero valve lift], the electronic actuator, which acts at least indirectly on the first slider 17, is de-energized or de-energized, so that the first slider 17 is displaced outwardly by its actuating device 22 in the form of a helical compression spring, and the ramp device 20 thereby moves the second slider 19 from its coupling position back. One end of the helical compression spring as actuator 22 is supported on a ring-shaped area 25 of the first slider 17, which is remote from the outer side 18 of the slider. At its other end, the helical compression spring as positioning device 22 acts on a ring 26 as stop in the transverse bore 16.

[0025] While the application has been described with reference to the example embodiments thereof, it is to be understood that the application is not limited to the example embodiments described and / or illustrated. Rather, the application is intended to cover various modifications and equivalent arrangements. In addition, while the various elements and method steps have been shown with reference to a certain combination of elements, other combinations are within the scope of the application.

[0026] List of reference signs

[0027] 1 component

[0028] 2 shaft member

[0029] 3 rocker arm assembly

[0030] 4 cam rocker arm

[0031] 5 valve rocker arm

[0032] 6 shaft member longitudinal end

[0033] 7 outer longitudinal end

[0034] 8 cam contact surface

[0035] 9 shaft member opposite longitudinal end

[0036] 10 outer longitudinal end

[0037] 11 valve contact surface

[0038] 12 end extension

[0039] 13 longitudinal wall

[0040] 14 web

[0041] 15 link slider assembly

[0042] 16 transverse bore

[0043] 17 first slider

[0044] 18 outer side

[0045] 19 second slider

[0046] 20 ramp means

[0047] 21 drive surface

[0048] 22 adjustment means

[0049] 23 connecting slot

[0050] 24 guide pin

[0051] 25 annular region

[0052] 26 stop

[0053] 27 tubular projection

[0054] 28 coil pack

[0055] 29 cam return spring

[0056] 30 aperture

[0057] 31 end leg

[0058] 32 end leg

[0059] 33 contact face

[0060] 34 flat

[0061] 35 window

[0062] 36 arcuate slot

Claims

1. An assembly (1) for a heavy-duty internal combustion engine with switchable valve drive, 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 of which is pivotably movable on the shaft (2) relative to the other rocker arm, wherein Cam roller (4) has a cam contact surface (8) on the outer longitudinal end (7) of the longitudinal end (6) of the shaft, the valve roller (5) has at least an indirect valve contact surface (11) on the outer longitudinal end (10) of the opposite longitudinal end (9) of the shaft, wherein the longitudinal center planes of the two rollers (4, 5) coincide, wherein the valve roller (5) ends on the longitudinal end (6) of the shaft with an end extension (12) and is attached to the longitudinal walls (13) of the cam roller (4), which are connected by a web (14) that at least partially covers the end extension (12), wherein a cam return spring (29) is provided between the rollers (4, 5), wherein the cam return spring (29) is clamped between the rollers (4, 5), wherein a coupling slider group (15) extends in the end extension (12), comprising a first slider (17) that is received in a transverse bore (16) of the end extension (12), wherein an outer side (18) is at least indirectly accessible by an electronic actuator, the transverse bore (16) being traversed by a bore (30) that extends in the upward direction of the valve roller (5), a second slider (19) being a further component of the coupling slider group (15) and being in translational connection with the first slider (17) via a ramp device (20), in the coupled mode the first slider being movable inwardly by the electronic actuator in such a way that, for the decoupled mode, the first slider (17) is movable rearwardly by adjustment means (22) in the event of deactivation of the electronic actuator, thereby causing the second slider (19) to segmentally engage a drive surface (21) of the web (14) of the cam roller (4), which releases the second slider (19) from the coupled mode.

2. Assembly according to claim 1, wherein the ramp device (20) of the coupling slider group (15) comprises a coupling groove (23) formed on one of the sliders (17, 19), wherein a guide pin (24) located on the other slider (19, 17) engages therewith.

3. Assembly according to claim 1, wherein the adjustment means (22) for the return of the first slider (17) are at least one compression spring that is clamped between a further outer side of the first slider (17) or an annular region (25) adjacent thereto and a stop (26) in the transverse bore (16).

4. Assembly according to claim 1, wherein the transverse bore (16) and / or the bore (30) that extends upwardly in the end extension (12) of the valve roller (5) is a through-hole.

5. Assembly according to claim 1, wherein a tubular projection (27) extends outwardly from each longitudinal wall (13) of the cam roller (4), by which the cam roller (4) is mounted on the shaft (2).

6. The assembly of claim 5 wherein at least one of the tubular projections (27) is surrounded by a coil (28) of a cam return spring (29) configured as a rotating leg spring with one end leg (31) supported on the cam rocker arm (4) and the other end leg (32) supported on the valve rocker arm (5).

7. The assembly of claim 1 wherein the second slider (19) in the end extension (12) of the valve rocker arm (5) has a contact face (33) that is a pawl to a flat (34) of the drive surface (21) of the web (14) of the cam rocker arm (4) that it engages in the coupled mode.

8. The assembly of claim 7 wherein the drive surface (21) of the web (14) of the cam rocker arm (4) is part of a window (35).

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