Lever device for a valve train of an internal combustion engine

Abstract

The invention relates to a lever device for a valve train of an internal combustion engine, having at least one first lever (3) and at least one second lever (4), wherein the levers (3, 4) are arranged side by side on a common pivot axis (2) and are pivotably supported relative to one another and are couplable for switching, wherein at least one stop (1) is provided to limit the pivoting movement of the levers (3, 4), characterized in that the stop (1) is arranged in the region of the pivoting bearing faces (5, 6) of the levers (3, 4).

Description

Technical Field

[0001] This invention relates to a lever device for the valve train of an internal combustion engine. Background Technology

[0002] For example, a valve train for an internal combustion engine is known in DE 10 2006 034 951 A1, which has a switchable rocker arm structure with multiple rockers pivotally supported on a fixed rocker arm shaft. Multiple positioning aids ensure that the rocker arm for switching is oriented such that alternating locking or unlocking is possible. Here, the positioning aids provided on the rocker arm are configured as stops supported on the camshaft. Summary of the Invention

[0003] Therefore, the purpose of this invention is to simplify the structure and manufacture of the lever device of the above type and to design it at a low cost.

[0004] The stated objective is achieved through the features of the invention. Further advantageous and claimed designs arise in the corresponding description and drawings.

[0005] Therefore, a lever device for the valve train of an internal combustion engine is proposed, the lever device having at least one first lever and at least one second lever, wherein the levers are arranged side by side on a common pivot axis and are pivotally supported relative to each other and coupled for switching. At least one stop is provided to limit the pivoting movement of the levers. To keep the component tolerance chain on the stop about the support axis as small as possible, the stop is disposed in the region of the pivot support surface of the lever. Thus, a stop with a simple construction can be realized, which can be manufactured with high precision and low cost while reducing the component tolerance chain.

[0006] Therefore, it is essential to ensure the precise positioning of the lever and the accurate and trouble-free switching of the lever in its final position precisely defined on the stop, under the lever's basic state.

[0007] In a particularly simple and space-saving manner, the stop can be formed by a protrusion on the first lever and a recess on the second lever, such that the protrusion can pivotally engage with the recess and rest against the recess on the second lever.

[0008] Here, in a particularly advantageous manner, protrusions and gaps can be formed on the pivot support surface of the lever.

[0009] Furthermore, it is particularly advantageous that the protrusion forms an extension of the pivot support surface on the first lever. In this way, by providing the protrusion, the force introduced into the pivot support portion of the lever can be controlled, and the pivot support surface on the first lever can be enlarged, thus reducing surface pressure. The stop can therefore be provided at any location on the support diameter, and thus can be easily adapted to installation and operating conditions. At the same time, the tolerance chain of the components on the stop with respect to the pivot or support axis can be optimally reduced. In addition, the stop can be integrated into the pivot support portion of the lever in a particularly space-saving and compact manner.

[0010] Another simplified design of the invention can be achieved as follows: the protrusion on the first lever is formed in the form of a ring segment and forms an extension of the pivot support surface on the first lever in its inner diameter. Therefore, the protrusion can be claw-shaped on the first lever for engagement on the second lever. Preferably, the protrusion also forms a first stop surface on at least one end side oriented in the pivot direction for abutting against the second lever. Alternatively, to limit pivoting movement in both pivot directions, stop surfaces are provided on both end sides of the protrusion oriented in the pivot direction.

[0011] The empty portion can be simply configured as a groove on the pivot support surface of the second lever and can have at least one second stop surface formed at at least one end in at least one pivot direction for abutting the protrusion. It is also conceivable that correspondingly oriented stop surfaces are provided at both ends of the empty portion to restrict pivoting movement in both pivot directions.

[0012] In another particularly preferred embodiment of the invention, a first lever having a pivot support surface and an extension of the pivot support surface formed on the protrusion, and a second lever having a pivot support surface, are slidably supported on the outer diameter of the pivot support shaft, respectively. Therefore, in the stop member, the component tolerance chain with respect to the support axis, and thus the manufacturing cost, can be minimized and accuracy can be further improved.

[0013] Preferably, the protrusion and the first lever are integrally formed, so that the extension of the pivot bearing surface formed by the protrusion is seamlessly connected to the pivot bearing surface.

[0014] Furthermore, the clearance on the second lever can be advantageously positioned in a region of the pivot bearing surface where a lower surface pressure occurs during operation.

[0015] Preferably, the lever is provided with a pivot support hole for supporting the lever on a pivot shaft, and a locking hole for forming a coupling mechanism for coupling the levers. Here, if a stop is formed on at least one first stop surface on the first lever and at least one second stop surface on the second lever, such that the stop surfaces are respectively in a plane with the central axis of the pivot support hole and the corresponding central axis of the locking hole, it is possible to further reduce the component tolerance chain at the stop, thereby further simplifying manufacturing and improving manufacturing accuracy.

[0016] In another particularly preferred embodiment of the invention, a first lever forms a rocker arm on the valve side having at least one valve contact section for operating at least one scavenging valve of the internal combustion engine, while a second lever forms a rocker arm on the cam side having at least one acquisition element for acquiring cam lift motion of the camshaft of the internal combustion engine. In this way, by providing a protrusion on the pivot support surface of the rocker arm on the valve side, the higher load generated in the pivot support surface of the rocker arm during valve operation can be better absorbed. Simultaneously, a clearance can be formed on the pivot support surface of the rocker arm on the cam side, which is subjected to a smaller load during operation. This allows for the realization of a low-cost, space-saving stop with high precision in a switchable rocker device, which can be driven by the camshaft of the internal combustion engine and has at least two rocker arms pivotally supported relative to each other on a common pivot axis for the valve train, wherein the rocker device has only one pivot axis.

[0017] The lever device can also include multiple groups arranged on a common pivot axis, each group having at least one first lever and at least one second lever, wherein the levers of each group are arranged side by side with each other and pivotally supported on the pivot axis relative to each other. Attached Figure Description

[0018] Other claimed features of the invention arise from the following description and the accompanying drawings, which illustrate several simplified embodiments of the invention. The drawings show:

[0019] Figure 1 A side view of the lever device of the valve train for an internal combustion engine according to the invention in a first operating state is shown.

[0020] Figure 2 A side view of the lever device in its second operating state is shown;

[0021] Figure 3 A perspective view of the lever device is shown;

[0022] Figure 4 A single, three-dimensional view of the first lever is shown;

[0023] Figure 5A single, three-dimensional view of the second lever is shown. Detailed Implementation

[0024] exist Figures 1 to 3 The lever device for a valve train of an internal combustion engine according to the invention, exemplarily shown in the figure, has a first lever 3 and a second lever 4, wherein levers 3 and 4 are arranged side by side on a common pivot axis 2 and are pivotally supported relative to each other. A stop 1 is used to limit the pivotal movement of levers 3 and 4 in a final position precisely defined on the stop 1 in a basic state, in which levers 3 and 4 can be coupled for switching. Levers 3 and 4 are slidably supported on the outer diameter of the common pivot axis 2 via pivot support surfaces 5 and 6 of pivot support portions, respectively, such that levers 3 and 4 are pivotable relative to each other in the plane of the figure. Pivot support surfaces 5 and 6 are formed on the inner diameter of pivot support holes 3a and 4a on levers 3 and 4, through which the common pivot axis 2 passes. Alternatively, pivot support surfaces 5 and 6 may also be part of rolling support portions of levers 3 and 4, respectively.

[0025] The first lever 3 is configured as a valve-side rocker arm, having a valve contact section 11 at its valve-side lever end for operating at least one scavenging valve (not shown) of the internal combustion engine. The second lever 4 serves as a cam-side rocker arm and has a receiving element 12 (here, a cam roller) at its cam-side lever end for receiving cam lift motion from the camshaft 13 of the internal combustion engine. In this way, the lever assembly forms a switchable rocker assembly. Figure 1 In the process, levers 3 and 4 switch to a decoupled state during the so-called lift-off period, wherein the second lever 4 is in an idle lift and cannot transmit valve lift to operate the valve. In order to return levers 3 and 4 to their basic state of not pivoting relative to each other during the idle lift period, a return spring mechanism (not shown) can be provided. Figure 2 The levers 3 and 4 are shown in their coupled basic state for operating the valves by transmitting valve lift.

[0026] Stop 1 is provided in the region of pivot support surfaces 5 and 6 of levers 3 and 4 and is formed by a protrusion 7 on the first lever 3 and a recess 8 on the second lever 4. Figure 1 , 24 and 5). In this way, high precision and accurate positioning of levers 3 and 4 in their basic state are achieved at the stop 1 while reducing the component tolerance chain and manufacturing cost about the support axis 14, wherein the support axis simultaneously forms the central axis of the pivot support holes 3a and 4a. Therefore, operational failures during switching are reliably avoided, especially jamming of the coupling mechanism used to couple levers 3 and 4, particularly during coupling and also reliably avoiding operational failures when decoupling levers 3 and 4. This is because the protrusion 7 engages in the recess 8 in a pivotally movable manner ( Figure 1 This achieves a space-saving design for the stop member 1. To restrict pivoting movement, the protrusion 7 can rest against the second stop surface 10 in the open portion 8 via the first stop surface 9. Figure 2 The protrusion 7 and the empty portion 8 are respectively formed on the pivot support surfaces 5 and 6 of levers 3 and 4. Figure 4 and 5 This allows the stop 1 to be easily integrated into the pivot support of levers 3 and 4.

[0027] Here, according to Figure 4 A protrusion 7 is formed on the axial extension 7a of the pivot support surface 5 on the first lever 3 and is constructed as a single piece with the first lever. The protrusion extends axially in a claw-like shape at the edge of the pivot support surface 5 on the longitudinal side of the first lever 3. The protrusion 7 has the shape of an annular segment and forms the extension 7a of the pivot support surface 5 on its inner diameter. The extension 7a is seamlessly connected to the pivot support surface 5, thereby increasing the pivot support surface on the first lever 3. On the end side oriented along the first pivot direction, the protrusion 7 forms a first stop surface for abutting against the second lever 4. It is feasible, but not necessarily required, to provide a stop surface on the other end side of the protrusion 7 oriented along the second pivot direction to limit pivoting movement in the second pivot direction. The first lever 3 is slidably supported on the outer diameter of the pivot shaft 2 by means of the pivot support surface 5 and the extension 7a formed on the inner diameter of the protrusion 7 of the pivot support surface. Figure 2 and 3 ).

[0028] The protrusion 7 is pivotally engaged at the same height with the corresponding recess 8 on the pivot support surface 6 of the second lever 4 via the extension 7a of the pivot support surface 5 on the first lever 3. Figure 1 The recess 8 creates free space on the second lever 4, allowing the protrusion 7, which engages with the first lever 3, to pivot relative to the second lever 4. In this case, the protrusion 7 can rest against the second stop surface 10 in the recess 8 by means of the first stop surface 9, to limit the pivoting movement of levers 3 and 4 in their basic state. Figure 2 ).

[0029] according to Figure 5 and 1 The empty portion 8 is disposed on the second lever 4 corresponding to the protrusion 7, axially opposite to the protrusion, and starting from the axial edge of the pivot support surface 6. The empty portion is configured as a groove that extends axially through the lever 4, and the groove forms a second stop surface 10 at the first end along the first pivot direction for abutting against the protrusion 7 in the basic state of the levers 3 and 4.

[0030] In the second pivoting direction, the clearance 8 extends circumferentially or in the pivoting direction to the second end, such that, with levers 3 and 4 decoupled, the protrusion 7 and the first lever 3 are freely pivotable during the free-lift stroke. It is feasible, but not necessarily necessary, to restrict the pivoting movement in the second pivoting direction by a stop surface on the second end of the clearance 8.

[0031] The clearance 8 is provided in the region of the pivot support surface 6 facing the upper side of the second lever 4, the upper side of which, in the installation position, faces away from the scavenging valve or the cylinder head of the internal combustion engine. Figure 1 , 2 (and 5). At this point, the lowest surface pressure occurs on the pivot support surface 6 on the second lever 4 during operation.

[0032] During the air lift, Figure 1 In the decoupled state shown, levers 3 and 4 can pivot relative to each other in the plane of the figure. In the decoupled state of levers 3 and 4, protrusion 7 can pivot with the first lever 3 in the recess 8 until it reaches the basic state of levers 3 and 4 in the cam base circle phase (Nockengrundkreis phase) along the pivot direction, as shown in... Figure 2 As shown, the protrusion 7 with the first stop surface 9 reaches the end of the empty portion 8 to abut against the second stop surface 10.

[0033] In order to couple the levers in the final position defined at the stop 1 in the basic state of levers 3 and 4, the first locking hole 15 on the first lever 3 and the second locking hole 17 on the second lever 4 are aligned with each other. Figure 2 , 4 And 5). Therefore, in the cam base circle stage ( Figure 2 The coupling element 16, movably disposed in the second locking hole 17 and having a coupling end, can be displaced across a small axial air gap into the opposing first locking hole 15 on the first lever 3. Here, levers 3 and 4 are coupled, and during the illustrated cam lift phase, the cam lift motion obtained from the camshaft 13 on the second lever 4 can be transmitted on the first lever 3 to at least one scavenging valve. Figure 2To decouple levers 3 and 4 in their basic state, the coupling element 16, with its coupling side end, can be moved outward and then backward from the first locking hole 15 into the second locking hole 17 during the cam base circle stage. The locking holes 15 and 17 are respectively configured as through holes in levers 3 and 4 near the pivot support holes 3a and 4a, extending parallel to the support axis 14 or the central axis of the pivot support holes 3a and 4a. The coupling element 16, here a cylindrical coupling bolt, and the locking holes 15 and 17 are parts of the coupling mechanism (not shown) that can be switched by an actuator system (not shown), preferably by an electric actuator. The operation for coupling or decoupling can also be performed in combination with a pre-stressed spring mechanism. The described coupling mechanism enables so-called lateral locking of levers 3 and 4, i.e., lateral locking transverse to the longitudinal axis of the levers. The high precision of the stop 1 also enables the implementation of coupling mechanisms with low component tolerances, especially the locking holes 15 and 17, thereby optimizing the force acting on the coupling element 16 and minimizing wear during operation.

[0034] The stop 1 can be installed at any position on the circumference or diameter of the pivot bearing surfaces 5 and 6. Figure 2 The diagram shows two alternative possible configurations for the stop 1, where the tolerance accuracy of the stop 1 is further improved. The alternative configurations for stops 1' and 1" are indicated by dashed lines. In both alternative configurations, the flat stop surfaces 9', 10' or 9" and 10" provided at the final positions defined by the stops 1' and 1" of the levers 3 and 4 are respectively located in the plane indicated by the dashed lines, along with the support axis 14 or central axis of the pivot support holes 3a and 4a and the central axis 18 of the locking holes 15 and 17. Figure 1 , 2 (4 and 5). Here, in the basic state, it is feasible to position the stops 1' and 1" circumferentially or clockwise along the diameter of the pivot bearing surfaces 5 and 6, pointing to the 3 o'clock direction in the first variant and the 9 o'clock direction in the second variant. Figure 2 ).

[0035] The pivot shaft 2 is fixed to the bearing member 20 via a helical connector 21 by means of the shaft section 19 extending from the first lever 3. Figure 3The actuator system for switching the coupling mechanism is at least partially housed in the housing section 22 of the carrier 20. It is also conceivable that components of the coupling mechanism are housed there. In this way, the levers 3 and 4, the pivot shaft 2, the coupling mechanism, and the actuator system, together with the carrier 20, form a pre-installed, switchable rocker unit that can be easily fixed to the internal combustion engine via the carrier 20 by means of the screw connector 21, particularly to the cylinder head or other fixed components.

[0036] List of reference numerals

[0037] 1. Stop component

[0038] 1' Stop component

[0039] 1” Stop

[0040] 2 Pivot axis

[0041] 3. Lever

[0042] 3a Pivot support hole

[0043] 4. Lever

[0044] 4a Pivot support hole

[0045] 5 Pivot support surface

[0046] 6 Pivot support surface

[0047] 7. Protrusion

[0048] 7a Extension

[0049] 8. Empty space

[0050] 9. Stop surface

[0051] 9' Stop surface

[0052] 9” stop surface

[0053] 10 Stop surfaces

[0054] 10' Stop surface

[0055] 10” stop surface

[0056] 11 Valve contact section

[0057] 12 Obtaining Components

[0058] 13 Camshaft

[0059] 14. Support axis, center axis

[0060] 15 Locking Holes

[0061] 16 Coupling Elements

[0062] 17 Locking Holes

[0063] 18. Central Axis

[0064] 19 Shaft Section

[0065] 20 Load-bearing components

[0066] 21. Spiral connector

[0067] 22 Shell Section

[0068] 23 Plane

Claims

1. A lever device for a valve train of an internal combustion engine, having at least one first lever (3) and at least one second lever (4), wherein the first lever (3) and the second lever (4) are arranged side by side on a common pivot axis (2) and are pivotally supported relative to each other and can be coupled for switching, wherein at least one stop (1) is provided to limit the pivoting movement of the first lever (3) and the second lever (4), characterized in that, The stop (1) is disposed in the region of the pivot support surface of the first lever (3) and the second lever (4).

2. The lever device according to claim 1, characterized in that, The stop (1) is formed by a protrusion (7) on the first lever (3) and a recess (8) on the second lever (4), such that the protrusion (7) is pivotally engaged in the recess (8) and can rest against the recess (8) on the second lever (4).

3. The lever device according to claim 2, characterized in that, The protrusion (7) is formed on the extension (7a) of the pivot support surface (5) on the first lever (3), while the empty portion (8) is formed on the pivot support surface (6) on the second lever (4).

4. The lever device according to claim 2 or 3, characterized in that, The protrusion (7) on the first lever (3) is formed in the form of a ring section and an extension (7a) of the pivot support surface (5) on the first lever (3) is formed on the inner diameter, and at least one first stop surface (9, 9', 9'') is formed on at least one end side oriented in the pivot direction for abutting against the empty portion (8).

5. The lever device according to claim 2 or 3, characterized in that, The empty portion (8) is configured as a groove on the pivot support surface (6) of the second lever (4) and forms at least one second stop surface (10, 10', 10'') at at least one end in at least one pivot direction for abutting the protrusion (7).

6. The lever device according to claim 3, characterized in that, The first lever (3) is slidably supported on the outer diameter of the pivot shaft (2) by the pivot support surface (5) on the first lever (3) and the extension (7a) formed on the protrusion of the pivot support surface, and the second lever (4) is slidably supported on the outer diameter of the pivot shaft by the pivot support surface (6) on the second lever (4).

7. The lever device according to claim 3, characterized in that, The protrusion (7) is integrally formed with the first lever (3) such that the extension (7a) of the pivot support surface (5) on the first lever (3) is seamlessly connected to the pivot support surface.

8. The lever device according to claim 2 or 3, characterized in that, The empty space (8) is located in the region of the pivot support surface (6) of the second lever (4) where a lower surface pressure occurs during operation.

9. The lever device according to any one of claims 1 to 3, characterized in that, Pivot support holes (3a, 4a) are provided on the first lever (3) and the second lever (4) for supporting the lever on the pivot shaft (2), and locking holes (15, 17) are provided for forming a coupling mechanism for coupling the first lever (3) and the second lever (4), wherein the stop (1) is formed on at least one first stop surface (9, 9', 9'') on the first lever (3) and at least one second stop surface (10, 10', 10'') on the second lever (4), such that the first stop surface (9, 9', 9'') and the second stop surface (10, 10', 10'') are respectively located in a plane (23) with the central axis (14) of the pivot support hole (3a, 4a) and the corresponding central axis (18a, 18b) of the locking hole (15, 17).

10. The lever device according to any one of claims 1 to 3, characterized in that, The first lever (3) is configured as a rocker arm on the valve side, the rocker arm having at least one valve contact section (11) for operating at least one scavenging valve of the internal combustion engine, while the second lever (4) is configured as a rocker arm on the cam side, the rocker arm having at least one acquisition element (12) for acquiring the cam lift motion of the camshaft (13) of the internal combustion engine.

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