Rocker arms designed for overhead mounting in a valve train of an internal combustion engine

Abstract

A rocker arm (1) designed for overhead mounting in a valve train of an internal combustion engine, which rocker arm (1) has at one longitudinal end (2) a contact surface (3) for a periodic lifting mechanism, and, looking towards its other longitudinal end (4), a bearing eye (5) for pivoting support against an surrounding structure, and at the other longitudinal end (4) a receiving bore (7) extending from its underside (6) in the direction away from gravity, with a hydraulic support element (9) fixedly and uprightly installed therein via its housing (8), the axially movable pressure piston (10) of which with a ball head (11) projects beyond the receiving bore (7), wherein a high-pressure chamber (15) for hydraulic fluid is formed between a side (12) away from the head of the pressure piston (10) and a base (13) of the housing (8), the base (13) being located near a top surface (14) of the rocker arm (1) in the direction of gravity. is,wherein a pressure piece (16) is loosely placed on the ball head (11) of the pressure piston (10) via a ball socket (17), so that an elephant's foot joint (18) is formed, which pressure piece (16) has a contact surface (20) for a gas exchange valve (21) or a valve bridge on its free end face (19) and is pivotably held together with the ball head (11) of the pressure piston (10) of the support element (9) by means of a wire bracket (22, 23).

Description

[0001] The invention relates to a rocker arm intended for overhead mounting in a valve train of an internal combustion engine.

[0002] The invention is based on a standard rocker arm, as disclosed, for example, in document DE 20 2024 100 621 U1. Such a rocker arm has, at one longitudinal end, a contact surface designed as a roller for a periodic stroke generator, then, viewed towards its other longitudinal end, a bearing eye for pivoting support relative to a surrounding structure, and at the other longitudinal end, a receiving bore running from its underside with a hydraulic element installed therein, which is referred to as an insert element. The insert element has a pressure piston that is axially movable relative to the receiving bore and is plugged together with a housing that is fixedly arranged in the receiving bore. The pressure piston projects downwards beyond the receiving bore with a spherical head. A high-pressure chamber for hydraulic fluid is formed below between the pressure piston and the housing.A pressure piece is mounted on the ball head of the pressure piston, allowing for angular movement, via a ball socket, forming an elephant's foot joint. The pressure piece has an inwardly bent ring collar at the edge of its socket. The pressure piece is snapped / flanged to the ball head via the latter, allowing for angular movement.

[0003] The task is to propose a standard rocker arm that is suitable for overhead mounting and whose hydraulic element is leak-proof.

[0004] According to the invention, this object is achieved in that the overhead rocker arm accommodates a hydraulic support element in its receiving bore, which is now located in the direction of gravity (at the top), which support element sits stationary and upright in the receiving bore via its housing, wherein the pressure piston, which is axially movable in the housing, projects beyond the receiving bore with its ball head, wherein the high-pressure chamber for the hydraulic medium is formed between a side of the pressure piston remote from the head and a bottom of the housing near an upper side of the rocker arm lying in the direction of gravity, wherein the pressure piece sits loosely on the ball head of the pressure piston via its ball socket and which pressure piece is held together pivotably with the ball head of the pressure piston of the support element via a wire bracket.

[0005] Due to this design, which makes use of a standardized hydraulic support element from mass production, the rocker arm is suitable for overhead installation. The support element, which is pre-filled with hydraulic oil and preferably only inserted afterward, does not leak due to its enclosed high-pressure chamber underneath. Another outstanding feature is that the pressure piece, which is preferably only joined after the aforementioned insertion of the support element, sits loosely and unsnapped via its ball socket on the head of the pressure piston of the support element and is pivotally held there via the simple and extremely inexpensive wire bracket. An inwardly flanged collar or the like on the pressure piece is not provided. Hydraulic oil losses do not occur with this simple attachment to the support element.

[0006] The wire clamp, which is preferably made of steel wire cut from a coil and bent, secures the thrust piece to the rocker arm during transport and facilitates its assembly. This clamp can also be used to prevent slipping during operation.

[0007] According to a particularly preferred development of the invention, the wire bracket consists of two superimposed, approximately horizontally running and unilaterally aligned loop-like surrounding arcs. The axially lower surrounding arc sits largely non-pivotably snapped into a complementary annular groove of the pressure piston below its ball head. The axially upper surrounding arc, in contrast, encloses a jacket section of the pressure piece in a relatively sliding manner. This means that the latter surrounding arc maintains its comparatively horizontal position during a pivoting movement of the pressure piece. The two circumferential arcs of the respective wire bracket are connected at one end via respective axial webs. To facilitate assembly, as further proposed, one of the surrounding arcs of the wire bracket is slotted. Alternatively, at least one of the surrounding arcs can also be designed as a serrated ring or the like.

[0008] According to a further refinement of the invention, the outer section of the thrust piece, which is wrapped around the axially upper arc of the wire bracket, tapers conically or spherically toward its free end, thus having a roof-like shape. This ensures good axial securing of the thrust piece.

[0009] Finally, it is proposed that the contact surface of the rocker arm be designed at one longitudinal end as a roller or sliding contact surface for direct cam counter-rotation. If necessary, a contact surface for a movable cam group or, for example, a push rod via a respective calotte could also be considered.

[0010] About the drawing: • Fig. 1 shows the rocker arm with support element and pressure piece fixed to it by a wire bracket; • Fig. 2 shows the support element with pressure piece and wire bracket and • the Fig. 3, Fig. 4 shows two variants of the wire bracket.

[0011] Fig. Figure 1 shows a rocker arm 1 in its final overhead installation position. At one longitudinal end 2, shown here on the left, the rocker arm 1 has a roller-shaped contact surface 3 for a lifting cam. Following this, toward its other longitudinal end 4, shown on the right, the rocker arm 1 has a bearing eye 5 for pivoting support relative to a surrounding structure.

[0012] At the other longitudinal end 4, the rocker arm 1 has a receiving bore 7 in its upper underside 6. A hydraulic support element 9, a standard part from mass production and typically used to support a rocker arm, is inserted upright therein. The support element 9 sits firmly in the receiving bore 7 via its pot-like housing 8. A pressure piston 10 is telescopically connected to the housing 8. This piston projects beyond the receiving bore 7 with its spherical head 11. It can be seen that a high-pressure chamber 15 for hydraulic fluid is formed between a lower side 12 of the pressure piston 10, remote from the head, and an underlying bottom 1 of the housing 8. The receiving bore 7 is a blind bore, with the latter bottom 13 of the housing 8 lying close to a top side 14 of the rocker arm 1, located below. The bottom 13 rests on a base 36 of the receiving bore 7.

[0013] A pressure piece 16 is loosely and angularly movable on the ball head 11 of the pressure piston 10 via its ball socket 17, forming an elephant foot joint 18. The pressure piece 16 has a contact surface 20 for a gas exchange valve 21 indicated here on its free end 19, which is largely flat or can also be slightly spherical. The pressure piece 16 is held together by a wire bracket 22 or 23 in a pivotable manner with the ball head 11 of the pressure piston 10 of the support element 9 (see also Fig. 2 - 4).

[0014] The respective wire bracket 22 (see Fig. 3) or 23 (see Fig. 4) is snapped / engaged into a complementary annular groove 26 of the pressure piston 10 by a first loop-like enclosing arc 24 or 25 shown below. The annular groove 26 is located below the ball head 11 of the pressure piston 10. With a second loop-like enclosing arc 27 or 28 shown above, the wire bracket 22 or 23 engages a casing section 29 of the pressure piece 16 in a relatively sliding manner. The casing section 29, as can be seen, runs roof-like and slightly curved towards the front 19 of the pressure piece 16. The two lower enclosing arcs 24, 25 are in both variants ( Fig. 3, Fig. 4) aligned in the same direction to the two upper surrounding arches 27, 28 and connected to each other at their ends 30, 31 remote from the arches via respective axial webs 32, 33.

[0015] It can be seen in Fig. 3, the first, lower surrounding arch 24 of the wire bracket 22 is slotted and formed from two separate arch sections 34 that converge toward each other in a clamp-like manner. The upper surrounding arch 27, on the other hand, is designed to be closed.

[0016] According to Fig. 4, the second, upper enclosing arch 28 of the wire bracket 23 is slotted and formed from two separate arch sections 35 that converge toward each other in a clamp-like manner. The lower enclosing arch 25, on the other hand, is again designed to be closed. List of reference numbers 1 rocker arm 2 Longitudinal end 3 Contact surface 4 Longitudinal end 5 bearing eye 6 Bottom 7 mounting hole 8 housings 9 Support element 10 pressure pistons 11 ball head 12 pages 13 Floor 14 Top 15 High-pressure room 16 Pressure piece 17 Ball socket 18 Elephant ankle 19 Forehead 20 contact surface 21 Gas exchange valve 22 wire hangers 23 wire hangers 24 enclosing arches 25 enclosing arches 26 ring groove 27 Enclosing arch 28 Enclosing arch 29 Sheath section 30 End 31 End 32 axial web 33 Axial web 34 arch section 35 arch section 36 Reason 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 20 2024 100 621 U1

[0002]

Claims

[1] Rocker arm (1) intended for overhead installation in a valve train of an internal combustion engine, which rocker arm (1) has at one longitudinal end (2) a contact surface (3) for a periodic stroke generator, then, viewed in the direction of its other longitudinal end (4), a bearing eye (5) for pivotally movable support relative to a surrounding structure, and at the other longitudinal end (4), a receiving bore (7) extending from its underside (6) lying in the direction away from the force of gravity, with a hydraulic support element (9) installed therein in a stationary and upright manner via its housing (8), the pressure piston (10) of which is axially movable therein and projects beyond the receiving bore (7) with a spherical head (11), wherein between a side (12) of the pressure piston (10) lying remote from the head and a bottom (13) of the housing (8), which bottom (13) runs close to an upper side (14) of the rocker arm (1) lying in the direction of gravity, a high-pressure chamber (15) for hydraulic fluid,wherein a pressure piece (16) is loosely placed on the ball head (11) of the pressure piston (10) via a ball socket (17), so that an elephant foot joint (18) is formed, which pressure piece (16) has a contact surface (20) for a gas exchange valve (21) or a valve bridge on its free end (19) and is held together by a wire bracket (22, 23) in a pivotable manner with the ball head (11) of the pressure piston (10) of the support element (9). [2] Rocker arm according to claim 1, wherein the wire bracket (22, 23) on the elephant foot joint (18) with a first loop-like surrounding arc (24, 25) is firmly snapped into a complementary annular groove (26) of the pressure piston (10) below its ball head (11) and with a second loop-like surrounding arc (27, 28) surrounds a casing section (29) of the pressure piece (16) in a relatively slidable manner, which first and second surrounding arcs ((24, 25), (27, 28)) are aligned in the same direction to one another and are connected to one another at their ends (30, 31) remote from the arc via axial webs (32, 33). [3] Rocker arm according to claim 1, wherein the first or the second enclosing arc ((24, 25), (27, 28)) of the wire bracket (22, 23) consists of two separate arc sections (34, 35) running towards each other in a clamp-like manner and the other of the two enclosing arcs ((24, 25), (27, 28)) is closed. [4] Rocker arm according to claim 1 or 2, wherein the casing section (29) of the pressure piece (16) tapers roof-like in the direction of its free end (19). [5] Rocker arm according to claim 1, wherein the contact surface (3) of the rocker arm (1) at one longitudinal end (2) is designed as a roller or sliding contact for direct cam counter-rotation.

Images