Bridge for valve drive of heavy duty internal combustion engine

Abstract

The invention proposes a bridge piece (1) for a valve drive of a heavy-duty internal combustion engine for transmitting a cam stroke to two identically acting gas exchange valves, which exists as a one-piece, inverted longitudinal bowl-shaped hollow body having two side walls (3) connected by a transverse wall (2), which is produced from a steel sheet blank (17) by deep-drawing technology, said transverse wall (2) having a platform (5) on each longitudinal end (4) of the bridge piece (1), which has a gas exchange valve contact surface (6) on its inner side (7), the platform (5) continuing in the manner of an overhang (8) in the longitudinal middle of the bridge piece (1), there being a contact area (10) for a periodic stroke generator present at the upper side (9) of the platform, the side walls (3) each having a window-shaped indentation (11) in the longitudinal section of the overhang, which is caused by a slit-shaped or hole-shaped punched-out portion (12) in the sheet blank.

Description

Technical Field

[0001] This invention relates to a bridging component for a valve drive mechanism in a heavy-duty internal combustion engine, used to transmit cam stroke to two identical shunting valves. The bridging component exists as a one-piece, inverted, longitudinally cup-shaped hollow body having two sidewalls connected by transverse walls, and is manufactured from a steel slab using a deep-drawing technique. Each transverse wall has a platform at each longitudinal end of the bridging component, with a shunting valve contact surface on its inner side. These platforms extend outwards with respect to the longitudinal center of the bridging component, and a contact area for a periodic stroke generator is located on their upper side. Background Technology

[0002] DE 20 2019 104 421 U1 discloses an elongated steel plate bridge for a valve drive in a heavy-duty internal combustion engine, having a central protrusion. A contact area for a periodic stroke generator is formed on the upper side of the protrusion. For example, a cam-driven rocker arm or rocker arm can be used as the stroke generator, or a cam / cam assembly can be used directly as the stroke generator.

[0003] DE 10 2010 011 455 A1 illustrates an additional bridging element. This additional bridging element is constructed as a solid part using casting or forging techniques. Furthermore, refer to DE 10 2015 211 124 A1. A bridging element with a hydraulically controlled clearance compensation element is disclosed therein.

[0004] "Heavy-duty internal combustion engine" should be understood as a machine, for example, that is used to drive heavy-duty vehicles, transport vehicles, light transport vehicles, agricultural operating equipment, ships, mining or construction equipment, etc. Summary of the Invention

[0005] The task is to create a bridging component as described above, which can be well-suited for deep drawing.

[0006] According to the present invention, this task is achieved by having the sidewalls inherently have window-shaped notches in the longitudinal sections of the corresponding protrusions, which are caused by slit-like or hole-like punches in the slab.

[0007] The two punches located in the deep-draw radius section of the sidewalls create crack-free protrusions during die modification. Because no material is present, the material in the sidewall region does not thin with the corresponding tensile stress. The tabs below the transverse walls at the lower part of the notches on each sidewall have a height greater than the depth of the sidewalls on their inner side in the vent valve contact surface. The applicant's tests and calculations also show that, due to the sufficiently high tabs retained below the respective window-shaped notches in the protrusion regions, there is no significant loss of rigidity. The final shape of the bridging member can be produced in one or more stretching stages.

[0008] Longitudinal slits or drill holes can be provided as suitable shapes for their respective punching parts, and different geometries can also be conceived and provided.

[0009] Furthermore, it is clear that these two notches also help reduce the mass of the bridging component, thus predictably resulting in less friction during operation, which has a positive impact on fuel consumption. When necessary, these notches also facilitate handling the bridging component during transport and assembly, as they allow for lateral tooling.

[0010] According to an improved embodiment of the invention, the "completed" notch should occupy as large an area as possible in the sidewall region of the protrusion. Advantageously, it should roughly and accurately cover the area where material thinning or even cracking might otherwise occur / will occur. The mentioned minimum of 40% here refers to the projected sidewall area of ​​the protrusion, the bottom side of which is determined by a connecting line along the flat upper side, and the upper side of which is determined by a line along the contact area parallel to the contact area. Furthermore, the trapezoid is limited by the outer side of the roof-like rising side of the protrusion. The notch may have a similar rectangular or trapezoidal geometry. The aforementioned lines used for measurement can be estimated here at half an arc of the edge radius, respectively.

[0011] As suggested in the design, the bridging frame is formed of steel plate with a thickness of 2-10mm, of which a variation of thick plate in the range of 3-6mm is preferred.

[0012] According to another specific embodiment of the invention, the sidewalls of the bridging member can be integrally connected at at least one longitudinal end by a transverse plate resembling a semi-ring. In this thus optional open-side design, tolerance compensation is well-suited, or it facilitates mounting the bridging member onto two valves, or adapting the bridging member to different valve spacings (for use on other types of internal combustion engines). Alternatively, the bridging member can also be connected at at least one longitudinal end by a flat transverse plate.

[0013] If the upper contact area is a convex spherical or cylindrical arched portion, then in the case of direct cam actuation, there is an increased cam actuation surface.

[0014] For example, a rigid material layer (such as a DLC layer) can be considered as the applied wear protection layer. A separate rigid material plate can also be applied if necessary. Attached Figure Description

[0015] In the attached image:

[0016] · Figure 1 The bridging component is shown in a spatial view;

[0017] · Figure 2 This shows a slab that has been stamped before the deep drawing process; and

[0018] · Figure 3 A quarter section is shown across the space passing through the bridging member. Detailed Implementation

[0019] Depend on Figure 1 , 3 A bridging component 1 for a valve transmission device of a heavy-duty internal combustion engine is known. The bridging component 1 is a one-piece inverted longitudinal bowl-shaped hollow body with two side walls 3 connected by an upper transverse wall 2. The two side walls are connected at the longitudinal end 4 of the bridging component 1 by a transverse plate 16 that is arched out in a semi-circular shape.

[0020] Bridging element 1 is used to transmit cam travel to two identical vent valves. This bridging element is derived from, in this case, an elliptical steel slab blank 17 (see...). Figure 2 It is deep-drawn in one or more steps. Preferably, the steel plate has a thickness of 3-6 mm.

[0021] At each longitudinal end 4, the transverse wall 2 has a platform 5, on the inner side 7 of which a vent valve contact surface 6 is provided. These platforms 5 transition into protrusions 8 towards the longitudinal center of the bridging member 1. The upper side 9 of the protrusion 8, which is flat or largely flat, has a contact area 10 for a periodic stroke generator (e.g., a rocker arm or swing arm driven by a cam). Optionally, a layer of hard material for wear protection may also be applied to this area, which is not shown.

[0022] like Figure 1 , 3 As shown, the sidewall 3 has a window-shaped notch 11 below its platform 5 in the protrusion 8, the notch being based on... Figure 1 Roughly rectangular, and according to Figure 3It roughly resembles an isosceles trapezoid. As can be seen here, the notch 11 occupies almost half of the respective area of ​​the side wall 3 included by the protrusion 8. Here, each side wall 3 retains a relatively high connecting piece 13 below the lower transverse wall 14 of the notch 11, which provides good structural reinforcement.

[0023] Each notch 11 is caused by a slit-like punch 12 applied to the slab 17. This punch is located precisely in the region of the slightly later stretch radius of each sidewall 3. Therefore, a relatively high protrusion 8 is formed during deep drawing without cracking. As can be seen, the large distance (e.g., ≥20 mm) between the ends of the two valve stems and the periodic stroke generator can be overcome by using the bridging member 1.

[0024] List of reference numerals

[0025] 1) Bridging components

[0026] 2) Transverse wall

[0027] 3) Sidewall

[0028] 4) Longitudinal end

[0029] 5) Platform

[0030] 6) Air exchange valve contact surface

[0031] 7) Inner side

[0032] 8) Protruding part

[0033] 9) Upper side

[0034] 10) Contact area

[0035] 11) Gap

[0036] 12) Breakout section

[0037] 13) Bridging components

[0038] 14) Transverse wall

[0039] 15) Inner side

[0040] 16) Horizontal plate

[0041] 17) Steel slab billet

[0042] H) Height of the splice

[0043] T) Depth of the sidewall

Claims

1. Bridge (1) for a valve drive of a heavy-duty internal combustion engine, for transmitting a cam stroke to two equally acting gas exchange valves, which bridge (1) exists as a one-piece, inverted longitudinal bowl-shaped hollow body with two side walls (3) connected by a transverse wall (2), and which bridge is made from a sheet steel blank (17) by deep-drawing technology, the transverse wall (2) having a platform (5) on each longitudinal end (4) of the bridge (1), which platform has a gas exchange valve contact face (6) on its inner side (7), wherein For the platform (5) in the longitudinal middle of the bridge (1) the overhang (8) is continued, at the upper side (9) of which an area of contact (10) for a periodic stroke generator is present, characterized in that the side walls (3) in the longitudinal section corresponding to the overhang (8) each have a window-shaped indentation (11) intrinsically, which is caused by a slit-shaped or hole-shaped punched-out portion (12) in the sheet blank.

2. The bridge of claim 1, wherein, Each indentation (11) occupies an area of at least 40% of the total area of the area of the side wall (3) projected by the overhang (8).

3. Bridge according to claim 1 or 2, characterized in that The tab (13) of each side wall (3) below the lateral wall (14) of the lower part of the indentation (11) has a height (H) which is greater than the depth (T) which the side wall (3) has on its inner side (15) in the gas exchange valve contact surface.

4. The bridge of claim 1, wherein, The bridge (1) is composed of a steel sheet of 2 mm to 10 mm thickness.

5. The bridge of claim 1, wherein, The side walls (3) of the bridge (1) are connected on at least one longitudinal end (4) by a lateral plate (16) which is raised like a half ring.

6. The bridge of claim 1, wherein, The area of contact (10) is flat or raised, wherein the area of contact has a convex spherical or cylindrical shape in the case of a raised design.

7. Bridge according to claim 1 or 6, characterized in that The area of contact (10) is provided with an applied wear protection layer on the upper side (9) of the overhang (8).

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