Component unit for an OHV valve train of a heavy-duty internal combustion engine

Abstract

A component (1) for an OHV valve train of a heavy-duty internal combustion engine is proposed, which component (1) is assigned to a cylinder of the heavy-duty internal combustion engine and comprises a support arm (2) with two rocker arms (3, 4) made of sheet steel below it, wherein each rocker arm (3, 4) has two side walls (7, 8, 9, 10) connected by a crossbar (5, 6), wherein a lower surface (11, 12) of the crossbar (5, 6) forms at one end a pushrod contact surface (13, 14) and at the other end an at least indirect valve mounting surface (15, 16), wherein a projection (18) with a ball head end (20) extends from a lower surface (17) of the support arm (2) for each rocker arm (3, 4), on which the respective rocker arm (3, 4) is connected via a cap (19) in a top surface (21, 22) whose crossbeam (5, 6) pivotably rests against it and wherein the support arm (2) has two guide surfaces (23) extending transversely to it for each rocker arm (3, 4), which are connected to sections of the side walls (7, 8,9, 10) of the respective rocker arm (3, 4) comb to its aligned guide.

Description

[0001] The invention relates to a structural unit for an OHV valve train of a heavy-duty internal combustion engine, which structural unit is assigned to a cylinder of the heavy-duty internal combustion engine and comprises a support arm which can be joined to a cylinder head of the internal combustion engine and has exactly two rocker arms, wherein an underside of the respective rocker arm forms at one end a contact surface for a periodic stroke generator and at the other end an at least indirect valve contact surface and wherein each rocker arm is articulated on the support arm via bearing means.

[0002] A “heavy-duty internal combustion engine” is a machine used, in particular, to drive a truck, van, light transporter, agricultural implement, ship, mining or construction equipment, etc.

[0003] A similar assembly, here for an OHC valve train of a heavy-duty internal combustion engine, is described in DE 10 2011 106 395 A1. The two rocker arms (intake and exhaust) are solid. At one end, equipped with a roller, they are each acted upon by a camshaft lobe. At the other end, which has an adjusting screw, they each act on a valve bridge. The support arm consists of a solid bearing block with pivoting axles on which the two rocker arms are pivotably mounted.

[0004] DE 103 02 469 A1 discloses a rocker arm for an OHV valve train. The rocker arm is solid and sits on an axle piece of a bearing block.

[0005] The task is to propose a simple and weight-reduced unit for an OHV valve train of a heavy-duty internal combustion engine.

[0006] According to the invention, a structural unit with two rocker arms for an OHV valve train of a heavy-duty internal combustion engine is provided, wherein the respective rocker arm is made of sheet steel and runs under the support arm, which respective rocker arm has two side walls connected by a crossbar, wherein an underside of the crossbar (as such) forms a push rod contact surface at one end and an at least indirect valve contact surface at the other end, wherein an extension with a spherical head end protrudes from an underside of the support arm for each rocker arm, against which extension the respective rocker arm rests pivotably via a calotte in an upper side of its crossbar, and wherein the support arm has two guide surfaces for each rocker arm which run transversely to the rocker arm and which mesh with sections of the side walls of the respective rocker arm for the aligned guidance of the rocker arm.

[0007] This results in a lightweight and cost-effective assembly, specifically for the valve train of a heavy-duty internal combustion engine. A key feature is the suspended arrangement of the two rocker arms, stamped and bent from sheet steel, beneath the (short) support arm. The two rocker arms are also easily aligned and thus secured against tilting by the support arm's guide surfaces. There is no hydraulic or mechanical lash adjuster in the rocker arms or support arm. Another notable feature is that, apart from an optional retaining clip, each rocker arm requires no additional components. The crossbeam of each rocker arm, which is U-shaped or inverted U-shaped in cross-section, has a cap at one end for a pushrod (underneath camshaft) and a surface section at the other end for preferential action on a valve bridge.

[0008] The respective extension with the ball head end under the support arm can be formed integrally with the latter. However, it is preferably provided separately. It is particularly preferred to accommodate this extension in a one-piece projection on the underside of the support arm. The respective projection is enclosed by the side walls of the rocker arm. In other words, it protrudes into the interior of the respective rocker arm. The inner surfaces of the side walls of the rocker arm are guided along the transverse walls of the projection, which thus represent key surfaces. This allows for easy alignment of the respective rocker arm.

[0009] Alternatively, the underside of the support arm can also be slotted to allow engagement of the side walls of the respective rocker arm, or the outer surfaces of the respective rocker arm can interact with guide webs of the support arm.

[0010] According to a further development of the invention, the respective extension, designed as a separate plug-in element, is intended to be a "standardized" pressure piston of a hydraulic lash adjuster. This could be a pressure piston of a rocker arm plug-in element or a support element for a rocker arm. This measure saves costs because mass production is possible.

[0011] A simple mounting of the respective rocker arm on the extension is achieved via a retaining clip connected to the extension. The clip is clipped / snapped onto the head of the extension. This allows the entire assembly with suspended rocker arms to be delivered externally pre-assembled to the engine for final assembly. Assembly work on the engine is eliminated. Alternatively, brackets or similar devices can be suspended from the support element to hold the two rocker arms.

[0012] In a more concrete implementation of the invention, a simple lubrication system for the bearing area of ​​each rocker arm on the plug-in element is proposed. A vertical channel is provided in each of the support arm and the plug-in element. The vertical channel in the support arm extends from the top of the support arm and conducts dripping oil. The vertical channel in the plug-in element extends through the top of the support arm to the cap in the crossbar of the rocker arm.

[0013] A further subclaim concerns practical measures for joining the assembly to the cylinder head via its support arm. Two or three guide columns, preferably one piece, are proposed, projecting from the support arm toward the cylinder head. These columns have holes for the passage of a screw, pin, or the like. Alternatively, webs can protrude from the cylinder head for connection to the support arm.

[0014] The two rocker arms of the assembly can also be designed to actuate, for example, two similarly acting or a group of similarly acting gas exchange valves.

[0015] About the drawing: • Fig. 1 shows a spatial view obliquely from above of the assembly unit, • Fig. 2 shows a longitudinal section through the first, in Fig. 1 left drawn rocker arm with support arm and • Fig. 3 shows a partial longitudinal section through the support arm with a cross-section of the first rocker arm in the area of ​​the attachment with plug-in element.

[0016] The figures show a component 1 for an OHV valve train of a heavy-duty internal combustion engine. Component 1 is assigned to exactly one cylinder of the heavy-duty internal combustion engine.

[0017] The structural unit 1 essentially consists of a support arm 2 which can be screwed to a cylinder head of the internal combustion engine and has two rocker arms 3, 4 made of sheet steel with a U-shaped cross section underneath.

[0018] The one in the foreground of Fig. The rocker arm 3 shown in Figure 1 acts on a first valve bridge 43, which actuates two intake valves 45 (or two exhaust valves). The other rocker arm 4, visible behind it, acts on a second valve bridge 44, which actuates two exhaust valves 45 (or two intake valves). Each rocker arm 3, 4 consists merely of two upright side walls 7, 8, 9, 10 connected by a crossbeam 5, 6. An underside 11, 12 of the crossbeam 5, 6 forms a domed push rod contact surface 13, 14 at one end and a bridge contact surface 15, 16 at the other end.

[0019] The support arm 2 is a short block, which essentially extends over the respective cylinder of the internal combustion engine and in its longitudinal direction, with a largely smooth-walled upper and lower surface 36, 17. A one-piece, dome-shaped projection 24 with a bore 32 protrudes from the lower surface 17 for each rocker arm 3, 4 (see Fig. 2, Fig. 3). An extension 18, designed as a separate plug-in element 30, is received in the bore 32 via its shaft 31. The extension 18 projects with its ball-head end 20 beyond a lower end 25 of the projection 24. The extension 18 is a standardized pressure piston of a hydraulic lash adjuster.

[0020] As can be seen from the Fig. 2, Fig. 3, the respective rocker arm 3, 4 rests pivotably on the ball head end 20 of the extension 18 via a cap 19 in an upper side 21, 22 of the crossbeam 5, 6 thereof. The upper side 21, 22 of the crossbeam 5, 6 of the respective rocker arm 3, 4 at the cap 19 is bridged by a retaining plate 33 with a window-like recess 34 fixed to the crossbeam 5, 6. The respective rocker arm 3, 4 is held by the engagement of the retaining plate 33 via its recess 34 in an undercut 35 in the extension 18 on the support arm 2 (transport, anti-skid protection during operation).

[0021] Furthermore, the Fig. 2, Fig. 3, that the respective extension 24 of the support arm 2 protrudes into an interior space 26, 27 of the associated rocker arm 3, 4 and is thus enclosed by its respective side walls 7, 8, 9, 10. Two flat, opposing transverse walls 28 of the respective extension 24 form guide surfaces 23 for each rocker arm 3, 4. These transverse walls 28 can thus also be referred to as key surfaces. A straight alignment of the rocker arms 3, 4 is achieved via contact between inner surfaces 29 of the side walls 7, 8, 9, 10 and the transverse walls 28 of the respective extension 24.

[0022] For lubrication of a contact area between the ball head end 20 of the extension 18 and the cap 19 of the respective rocker arm 3, 4, a first lubricating oil channel 37 leads from the upper side 36 to the lower side 36, 17 of the support arm 2. This is connected to a second lubricating oil channel 38, which is located below it as seen in the direction of gravity, through the extension 18 and its ball head end 20 (see Fig. 3). Dripping oil from the cylinder head area is collected and fed into the system.

[0023] The support arm 2 has a total of three columns 40, 41, 42 protruding from its underside 17 for screwing to the cylinder head (see Fig. 1). Columns 40, 41 are located at its longitudinal transverse ends 39, and column 42 is positioned between the two projections 24.

[0024] As shown, the assembly unit 1 can be delivered externally pre-assembled to the cylinder head of the internal combustion engine. List of reference numbers 1 unit 2 support arms 3 rocker arms 4 rocker arms 5 crossbeams 6 crossbeams 7 Side wall 8 Side wall 9 Side wall 10 Side wall 11 Subpage 12 Bottom 13 Push rod contact surface 14 Push rod contact surface 15 Valve contact surface, bridge contact surface 16 Valve contact surface, bridge contact surface 17 Subpage 18 Extension 19 dome 20 ball head end 21 Top 22 Top 23 Guide surface 24 Approach 25 Lower forehead 26 Interior 27 Interior 28 Cross wall 29 inner surface 30 plug-in elements 31 shaft 32 bore 33 retaining plate 34 recess 35 undercut 36 Top 37 Lubricating oil channel 38 Lubricating oil channel 39 Transverse forehead 40 column 41 Column 42 Column 43 Valve bridge 44 Valve bridge 45 Inlet valve 46 Exhaust valve QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2011 106 395 A1

[0003] DE 103 02 469 A1

[0004]

Claims

[1] Construction unit (1) for an OHV valve train of a heavy-duty internal combustion engine, which construction unit (1) is assigned to a cylinder of the heavy-duty internal combustion engine and comprises a support arm (2) which can be joined to a cylinder head of the internal combustion engine and has exactly two rocker arms (3, 4) made of sheet steel underneath, wherein the respective rocker arm (3, 4) has two side walls (7, 8, 9, 10) connected by a crossbar (5, 6), wherein an underside (11, 12) of the crossbar (5, 6) forms at one end a push rod contact surface (13, 14) and at the other end an at least indirect valve contact surface (15, 16), wherein from an underside (17) of the support arm (2) for each rocker arm (3, 4) protrudes an extension (18) with a spherical head end (20), to which the respective rocker arm (3, 4) is connected via a calotte (19) in an upper side (21, 22) of the crossbar (5, 6) of which it rests in a pivotable manner, and wherein the support arm (2) has two guide surfaces (23) extending transversely thereto for each rocker arm (3, 4),which mesh with sections of the side walls (7, 8, 9, 10) of the respective rocker arm (3, 4) to guide it in an aligned manner. [2] Assembly according to claim 1, wherein a projection (24) is formed integrally on the underside (17) of the support arm (2) for each rocker arm (3, 4), from the lower end (25) of which projection the extension (18) with the ball head end (20) for the respective rocker arm (3, 4) protrudes, wherein the projection (24) projects into an interior space (26, 27) of the respective rocker arm (3, 4) and whose transverse walls (28) form the guide surfaces (23) of the support arm (2), which mesh with inner surfaces (29) of the side walls (7, 8, 9, 10) as the sections for the guide purpose. [3] Assembly according to claim 2, wherein the respective extension (18) with the ball head end (20) of the support arm (2) is a separate plug-in element (30) which is received via its shaft (31) in a bore (32) of the extension (24) of the support arm (2). [4] Assembly according to claim 3, wherein the respective plug-in element (30) is in the form of a standardized pressure piston of a hydraulic play compensation element. [5] Assembly according to one of claims 1-3, wherein the upper side (21, 22) of the crossbar (5, 6) of the respective rocker arm (3, 4) is bridged at the cap (19) by a rocker arm-fixed retaining plate (33), the window-like recess (34) of which is seated in an undercut (35) in the extension (18) for the purpose of retaining the respective rocker arm (3, 4). [6] Assembly according to one of claims 1-3, wherein for each rocker arm (3, 4) a first lubricating oil channel (37) leads from an upper side (36) to the underside (17) of the support arm (2), which first lubricating oil channel (37) is connected to a second lubricating oil channel (38) through the extension (18) and its ball head end (20) to the cap (19) in the crossbeam (5) of the rocker arm (3, 4). [7] Assembly according to claim 1, wherein the two rocker arms (3, 4) have an upright U-design in cross-section. [8] Assembly according to claim 1, wherein a screw connection / pin connection of the support arm (2) to the cylinder head is provided via a column (40, 41) projecting from the underside (17) of the support arm (2) at each of its transverse ends (39) and optionally via a column (42) located longitudinally centrally between the two rocker arms (3, 4). [9] Assembly according to claim 1, wherein one of the rocker arms (3, 4) is an inlet rocker arm and the other of the rocker arms (3, 4) is an outlet rocker arm, wherein their valve contact surfaces (15, 16) are provided for contacting a respective valve bridge. [10] Assembly according to claim 1, wherein the assembly (1) is installed externally pre-assembled on the cylinder head of the heavy-duty internal combustion engine.

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