CN113530630A

CN113530630A - Bridge piece for a valve gear of a heavy-duty internal combustion engine

Info

Publication number: CN113530630A
Application number: CN202110371677.6A
Authority: CN
Inventors: 达维德·朗; 帕特里克·西格尔; 米夏埃尔·舍韦; 罗伯特·卡姆
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Holding China Co Ltd
Priority date: 2020-04-21
Filing date: 2021-04-07
Publication date: 2021-10-22
Also published as: DE102020110750A1

Abstract

The invention relates to a bridge (1) for a valve gear of a heavy-duty internal combustion engine for transmitting a cam stroke to two gas exchange valves having the same function, wherein the bridge (1) is designed as a one-piece, inverted longitudinal bowl-shaped hollow body having two side walls (3) connected by a transverse wall (2), wherein the bridge is produced from a sheet-metal blank (17) by deep drawing, wherein the transverse wall (2) has a platform (5) at each longitudinal end (4) of the bridge (1), wherein the platform has a gas exchange valve contact surface (6) on the inner side (7), wherein the longitudinal central platform (5) of the bridge (1) continues in the manner of a projection (8), wherein a contact area (10) for a periodic stroke generator is present on the upper side (9) of the platform, and wherein the side walls (3) each have a window-shaped recess (11) in the longitudinal section of the projection, the indentations are caused by slot-shaped or hole-shaped punched-out sections (12) in the sheet metal blank.

Description

Bridge piece for a valve gear of a heavy-duty internal combustion engine

Technical Field

The invention relates to a bridge for a valve gear of a heavy-duty internal combustion engine for transmitting a cam path to two gas exchange valves having the same function, said bridge being designed as a one-piece, inverted longitudinal bowl-shaped hollow body having two side walls connected by a transverse wall and being produced from a sheet steel blank by deep drawing. The transverse wall has a platform on each longitudinal end of the bridge, which platform has gas exchange valve contact surfaces on its inner side, wherein the platforms continue in the manner of a projection in relation to the longitudinal middle of the bridge, at the upper side of which there is a contact region for the periodic stroke generator.

Background

DE 202019104421U 1 discloses an elongated steel plate bridge for a valve gear of a heavy-duty internal combustion engine, having a central extension, on the upper side of which contact regions for a periodic stroke generator are formed. For example, a swing arm or rocker arm of a cam drive is used as stroke generator or a cam/cam set is used directly as stroke generator.

DE 102010011455 a1 shows a further bridge. The further bridge is constructed as a solid piece in a casting or forging technique. Furthermore, reference is made to DE 102015211124 a 1. A bridge with a hydraulic play compensation element is disclosed.

By "heavy-duty internal combustion engine" is understood a machine, which is used, for example, for driving load-carrying vehicles, transport vehicles, light transport vehicles, agricultural work equipment, ships, mining or construction equipment, etc., among others.

Disclosure of Invention

The task is to create a bridge as described above, which can be deep drawn well.

According to the invention, this object is achieved in that the side walls in the longitudinal sections of the extension each have an opening in the form of a window, which is caused by a slot-like or hole-like punch-out in the blank.

Due to the two punches located in the section of the deep drawing radius of the side wall, a crack-free projection is formed during the modification in the die. Since no material is present, the material in the region of the side walls is not thinned with corresponding tensile stress. It has also been found by the applicant tests and calculations that there is no significant loss of rigidity due to the sufficiently high tab remaining under the respective window-shaped notch in the region of the projection (see dependent claim 3). The final shape of the bridge can be produced here in one or more stretching stages.

As a suitable shape for the respective punch-out, a longitudinal slot or a bore can be provided, wherein geometries differing from these are also conceivable and provided.

It is also clear that these two recesses also contribute to a reduction in the mass of the bridge, so that during operation, low friction can be expected, which has a positive effect on the fuel consumption. These indentations also facilitate handling of the bridge during transport and assembly if necessary, since it is possible to effect the tools to act laterally.

According to a development of the invention (dependent claim 2), the "finished" recess should occupy as large an area as possible in the region of the side wall at the projection. Advantageously, it should cover substantially exactly the area where otherwise thinning or even rupture of the material may occur/may occur. The minimum of 40% mentioned here relates to the projected side wall area of the projection, the bottom side of which is determined by a connecting line along a flat upper side, the upper side of which is determined by a line parallel to the contact area along the contact area. The trapezoid is also limited by the outer side of the roof-shaped rising side of the protruding portion. The indentations may have a rectangular-like or trapezoidal-like geometry. The aforementioned lines for measurement can in this case be evaluated in each case over half a radian of the edge radius.

As also suggested in the design, the bridge carrier is formed from a steel plate with a thickness of 2-10mm, wherein thick plate variants in the range of 3-6mm are preferred.

According to a further embodiment of the invention, the side walls of the bridge can be connected in one piece at least one longitudinal end by a transverse plate like a half ring. In the case of a design which is therefore optionally open on one side, tolerance compensation can be carried out very well, or the bridge can be fitted to two gas exchange valves, or it can be adapted to different valve spacings (for use in other types of internal combustion engines). Alternatively, the bridge parts can also be connected at least one longitudinal end by a flat transverse plate.

If the upper contact region is a convex or cylindrical bulge, an increased cam run-on surface is present in the case of direct cam running-on.

For example, a hard material layer (e.g., a DLC layer) is conceivable as an applied wear protection layer. If necessary, separate plates of hard material may also be applied.

Drawings

In the drawings:

fig. 1 shows the bridge in a spatial view;

fig. 2 shows a blank that is finished before the deep-drawing process; and is

Fig. 3 shows a quarter section through the space of the bridge.

Detailed Description

Fig. 1 and 3 show a bridge 1 for a valve drive of a heavy-duty internal combustion engine. The bridge 1 is a one-piece, inverted longitudinal bowl-shaped hollow body with two side walls 3 connected by an upper transverse wall 2, which are connected at the longitudinal ends 4 of the bridge 1 by a transverse plate 16 that arches like a half ring.

The bridge 1 serves to transmit the cam path to two gas exchange valves acting in the same way. The bridge is deep-drawn in one or more steps from a steel sheet blank 17 (see fig. 2), here oval. Preferably, the steel plate has a thickness of preferably 3-6 mm.

At each longitudinal end 4, the transverse wall 2 has a platform 5 with a gas exchange valve contact surface 6 on its inner side 7. These platforms 5 transition into a projection 8 in the direction of the longitudinal middle of the bridge 1. The upper side 9 of the extension 8, which is flat or largely flat here, has a contact region 10 for a periodic stroke generator (for example a cam-driven rocker arm or a swing arm). Optionally, a hard material layer for wear protection can also be applied in this region, not shown.

As shown in fig. 1 and 3, the side walls 3 each have a window-shaped cutout 11 in the extension 8 below their platform 5, which cutout is substantially rectangular according to fig. 1 and substantially resembles an isosceles trapezoid according to fig. 3. It can be seen here that the indentation 11 occupies almost half of the respective area of the side wall 3 which is comprised by the projection 8. In this case, the respective side wall 3 has a relatively high, structurally well-reinforced web 13 remaining below the lower transverse wall 14 of the recess 11.

The respective recess 11 is caused by a slot-like punch-out 12 which is respectively provided in the blank 17. The punch-out is located in the region of the later drawing radius of the respective side wall 3. Thus, a relatively high extension 8 is formed without cracks during deep drawing (see also the claim for advantages). As can be seen, with the bridge 1, a large distance (e.g. > 20mm) between the ends of the two valve stems and the periodic stroke generator can be overcome.

List of reference numerals

1) Bridging piece

2) Transverse wall

3) Side wall

4) Longitudinal end part

5) Platform

6) Contact surface of gas exchange valve

7) Inner side

8) Extension part

9) Upper side

10) Contact zone

11) Gap

12) Punching part

13) Bridging piece

14) Transverse wall

15) Inner side

16) Transverse plate

17) Steel plate blank

H) Height of the tab

T) depth of the side wall.

Claims

1. Bridge (1) for a valve gear of a heavy-duty internal combustion engine for transmitting a cam stroke to two gas exchange valves having the same function, the bridge (1) being present as a one-piece, inverted longitudinal bowl-shaped hollow body having two side walls (3) connected by a transverse wall (2), and being produced from a steel plate blank (17) by deep drawing, 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 surface (6) on its inner side (7), wherein for a longitudinal middle of the bridge (1) the platform (5) continues in the manner of a projection (8) at its upper side (9) with a contact region (10) for a periodic stroke generator, characterized in that, the side walls (3) each have an aperture-shaped recess (11) in the longitudinal section of the extension (8), said recess being caused by a slot-shaped or hole-shaped punch-out (12) in the blank.

2. Bridge according to claim 1, characterized in that each notch (11) occupies an area of at least 40% of the total area of the side wall (3) comprised by the projection (8).

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

4. Bridge according to claim 1, characterized in that the bridge (1) consists of a steel plate 2 to 10mm thick.

5. Bridge according to claim 1, characterized in that the side walls (3) of the bridge (1) are connected on at least one longitudinal end (4) by a transversal plate (16) that bulges like a half ring.

6. Bridge according to claim 1, characterized in that the contact area (10) is flat or bulged, wherein the contact area has a convex spherical or cylindrical shape in the case of the bulged shape.

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