Bridge components for valve trains in heavy-duty internal combustion engines

Abstract

The present invention proposes a bridge component (1) for a valve mechanism of a heavy-duty internal combustion engine, the bridge component being used to transmit cam lift to two identically functioning gas exchange valves, the bridge component having a sliding surface (2) on the upper side (4) and two valve contact surfaces (3) on the lower side (5), the valve contact surfaces being located on each longitudinal end (6) of the bridge component and including a guide column (7) fixedly extending from the lower side (5) between the longitudinal ends, the guide column being a separate component relative to the bridge component, the bridge component being made of steel plate and having an inverted basin-shaped geometry having a bottom (8), the guide column including a head (11) and a rod portion (12) that is reduced in diameter relative to the head portion, the head being located on the outer side of the bottom of the bridge component and serving as a sliding surface, and the rod portion extending through a hole (14) in the bottom and beyond a lower edge (15) of the bridge component, the valve contact surfaces being located on the inner side of the bottom.

Description

Technical Field

[0001] The present invention relates to a beam-shaped bridge component for a valve mechanism of a heavy-duty internal combustion engine, wherein the bridge component is used to transmit cam lift to two exhaust valves with the same function, and the bridge component has a sliding surface for a lever-type cam follower on the upper side of the bridge component and two valve contact surfaces on the lower side, wherein the valve contact surface is located on each longitudinal end of the bridge component and includes a guide column fixedly extending from the lower side between the longitudinal ends, and the guide column is used to telescopically guide the bridge component on the cylinder head of the internal combustion engine. Background Art

[0002] A “heavy-duty internal combustion engine” is understood to mean a machine which is used, in particular, to drive trucks, large passenger cars, transport vehicles, light transport vehicles, agricultural equipment, ships, mining equipment or construction equipment.

[0003] This type of valve bridge components, particularly for large-volume, mass-controlled internal combustion engines, is commercially available from the Italian company "Gnutti Carlo SPA". Website link: http: / / www.gnutticarlo.com / en / products / valve-bridges.

[0004] It is important to emphasize that the guide pins of the forged or cast solid bridge component are constructed integrally with the bridge component base body. Subsequently, the guide pin bores for arranging the guide pins on the cylinder head pins must be machined, and the entire component is finished by hardening, coating, polishing, etc. The rod and valve contact surfaces are also remachined.

[0005] DE 10 2010 011 455 A1 discloses another bridge component for a valve train of a heavy-duty internal combustion engine, which is also of solid construction but is not guided telescopically relative to the cylinder head. Summary of the Invention

[0006] The object of the present invention is to provide a cost-effective bridge element which can be constructed in a simple manner and can be used variably.

[0007] According to the invention, this object is achieved in that the guide column is a separate component from the bridging part, the bridging part is composed of steel sheet and has an inverted basin-shaped geometry with a bottom and side walls depending from the bottom, the side walls being connected at the longitudinal ends by transverse walls, wherein the guide column comprises a head and a shank that is reduced in diameter relative to the head, the head being located on the outer side of the bottom of the bridging part and serving as a sliding surface, and the shank extending through a hole in the bottom and beyond the lower edge of the bridging part, and wherein the valve contact surface is located on the inner side of the bottom.

[0008] Thus, an assembly is provided which consists of an inverted, cup-shaped bridge element with separate guide posts and which can be produced cost-effectively. The bridge element, which has an inverted U-shaped cross section, itself consists of deformed sheet metal, preferably steel sheet metal, and in a suitable embodiment of the invention can also be formed from thick sheet metal with a wall thickness of approximately 3-6 mm. Depending on the load conditions, wall thicknesses of up to approximately 10 mm or less than 3 mm are also conceivable and can be provided.

[0009] It is particularly advantageous that the individual components can be individually finished before they are joined together, which reduces production costs and simplifies handling.

[0010] Another advantage of the proposed two-part design is that it allows for a high degree of standardization. This allows, for example, bridge elements of the same size to be paired with guide pins of different sizes and / or with different wear protection measures. It is also conceivable and possible to provide identically designed guide pins for groups of different bridge elements. Thus, the modular kit covers a wide range of applications with a relatively small number of pre-assembled modular components.

[0011] According to the invention, the side walls and transverse walls of the bridge element form a peripheral edge. If necessary, the bridge element can also be open or recessed at at least one longitudinal end. The bridge element can be guided onto the valve stem of the gas exchange valve via the inner surface of the transverse wall and via the adjacent side wall sections.

[0012] As described in a refinement of the present invention, the guide pin is produced by extrusion, for example, reverse extrusion, and has a preferably upset head. Alternatively, the guide pin can also be deep-drawn, forged, or machined. If necessary, standardized mass-produced parts with minor modifications are also conceivable. The guide pin is guided via the bore of its shank onto a corresponding mating contour, such as a pin, in the cylinder head. If necessary, the shank can also be guided via its outer surface in a bore in the cylinder head or another suitable surrounding structure.

[0013] It is particularly important to emphasize that the head of the separate guide pin here has a mating surface for the rocker arm (or lifting cam, etc.). Therefore, the head can be provided with a special wear protection structure as described above, in addition to the bridge element. This includes, for example, a DLC coating or a general ceramic layer. It is also conceivable to perform a separate heat treatment, for example, only in the head area, or to perform a special finishing of the sliding profile by introducing at least one targeted or random cavity (which can also be a groove) that can serve as a lubricant reservoir.

[0014] Another refinement of the present invention involves a suitable geometric design of the bridge element. On the one hand, the bridge element can be designed as a substantially flat basin, i.e., without a projection in the bottom. This design is particularly cost-effective to manufacture. If necessary, the required assembly dimensions between the lever slide and the gas exchange valve in the cylinder head can be achieved by maintaining a correspondingly thick head portion of the guide strut.

[0015] It is also conceivable and conceivable to simply put it in a way that the bridge element is raised in the middle, with the guide pin being arranged with its head in the central raised area of ​​the base. As mentioned above, the required assembly dimensions in the cylinder head can also be achieved by maintaining a correspondingly thick head of the guide pin. However, in both implementations, the general setting of the valve clearance can be conveniently performed at a conventional location in the valve train design, for example, via an adjusting screw on the rocker arm or a hydraulic clearance adjustment element. This arrangement can also be omitted in very low-cost variants. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Regarding the attached pictures:

[0017] Figure 1 The completed installed bridge member is shown in perspective view, and

[0018] Figure 2 Shown Figure 1 Longitudinal section of the bridging component. DETAILED DESCRIPTION

[0019] Figure 1 and Figure 2 A bridge element 1 made of sheet steel for a valve train of a heavy-duty internal combustion engine is shown. The bridge element 1 serves to transmit the cam lift to two identically acting gas exchange valves.

[0020] The bridge element 1 has an inverted cup-shaped geometry. Two side walls 9 extend from the bottom 8 of the geometry and are connected at the longitudinal ends 6 by a transverse wall 10. The valve contact surface 3 is formed on the inner side 16 of the bottom 8 at the longitudinal ends 6.

[0021] A separate guide pin 7 is fixedly accommodated in a longitudinally central hole 14 in the base 8. The guide pin serves to telescopically guide the bridge element 1 on the cylinder head of the internal combustion engine. The guide pin 7 can extend into the hole 14 in the base 8 with a press fit or a clearance fit. The guide pin has a head 11 and a shank 12 that is reduced in diameter relative to the head. The head is located on the outer side 13 of the base 8 of the bridge element 1 and serves as a sliding surface for a lever-like cam follower (rocker arm, swing link, or drawbar). The shank extends through the hole 14 in the base 8 and projects beyond the lower edge 15 of the bridge element 1.

[0022] like Figure 2As shown, the rod portion 12 of the guide column 7 has an open structure similar to a pipe so as to be arranged on the guide pin of the cylinder head.

[0023] Regarding the geometry of the bridge element 1, it should be noted that the bridge element 1 has a longitudinal middle portion 17 that is raised like a roof, in which the opening 14 and the guide pin 7 located therein are located. The area of ​​the bottom 8 that adjoins the longitudinal ends 6 of the bridge element 1 is designed in a platform-like manner, so that a flat valve contact surface 3 is present on the inner side 5.

[0024] In addition, Figure 2 1 shows a cavity 18 (recess) in the center of the sliding surface 2 of the head 11 of the guide stud 7. The cavity serves as a lubricant reservoir.

[0025] The relatively large installation distances between the end faces of the valve stems of the two gas exchange valves and the contact surfaces of rocker arms or other types of cam followers can also be effectively bridged by the correspondingly thick heads 11 of the guide pins 7. As a result, the degree of deformation (keyword: drawing depth) of the bridging element 1 can be kept relatively small.

[0026] Reference Signs List

[0027] 1 Bridge component

[0028] 2 Sliding surface

[0029] 3 Valve contact surface

[0030] 4 upper side

[0031] 5 Lower side

[0032] 6 Longitudinal ends

[0033] 7 Guide column

[0034] 8 Bottom

[0035] 9 Sidewall

[0036] 10 horizontal walls

[0037] 11 Head

[0038] 12 Rod

[0039] 13 outside

[0040] 14 holes

[0041] 15 bottom edge

[0042] 16 Inside

[0043] 17 longitudinal middle part

[0044] 18 Concave cavity.

Claims

1. A beam-shaped bridge component (1) for a valve train of a heavy-duty internal combustion engine, the bridge component being used to transmit a cam lift to two identically acting gas exchange valves, the bridge component having a sliding surface (2) for a lever-type cam follower on the upper side (4) of the bridge component (1) and two valve contact surfaces (3) on the lower side (5), wherein: The valve contact surface (3) is located on each longitudinal end (6) of the bridge component (1) and includes a guide column (7) fixedly extending from the lower side (5) between the longitudinal ends, and the guide column is used to telescopically guide the bridge component (1) on the cylinder head of the internal combustion engine, characterized in that the guide column (7) is a separate component relative to the bridge component (1), and the bridge component (1) is composed of steel plate and has an inverted basin-shaped geometry, which has a bottom (8) and a side wall (9) cantilevered from the bottom, the side wall The guide column (7) is connected at the longitudinal end (6) by a transverse wall (10), wherein the guide column (7) comprises a head (11) and a stem (12) which is reduced in diameter relative to the head, the head (11) being located on the outer side (13) of the bottom (8) of the bridging part (1) and serving as the sliding surface (2), and the stem (12) extending through the hole (14) of the bottom (8) and beyond the lower edge (15) of the bridging part (1), and wherein the valve contact surface (3) is located on the inner side (16) of the bottom (8).

2. The bridge member according to claim 1, characterized in that The stem (12) of the guide column (7) is a thin-walled tube that is open at a position away from the head.

3. The bridge member according to claim 2, characterized in that The guide column (7) is formed by extrusion and its head (11) is realized by upset forging.

4. The bridge member according to claim 1, wherein: The bottom (8) of the bridge member (1) has a substantially planar profile on the inner side.

5. The bridge member according to claim 1, wherein: The bottom (8) of the bridge element (1) has a longitudinal middle portion (17) that rises like a roof, in which the hole (14) and the guide column (7) located therein are located.

6. The bridge member according to claim 1, wherein: The sliding surface (2) of the head (11) of the guide pin (7) has either a) a central recess (18) or b) a plurality of recesses, which serve as lubricant reservoirs.

7. The bridge member according to claim 1, 3 or 4, characterized in that Guide posts (7) with heads (11) grouped by thickness are pre-stored to match assembly dimensions of different heights.

8. The bridge member according to claim 1, wherein: The wall thickness of the bridge element (1) is in the range of 3 to 6 mm.

9. The bridge member according to claim 1, wherein: The guide pin (7) is a separate component which is joined to the bridge part (1) in the final processing state.

Images