DE102016207503A1 - Variable valve train - Google Patents

Abstract

Valve train (1) of an internal combustion engine, with a longitudinally in a carrier head (2) axially displaceable sliding axis (3) on which each cylinder of the internal combustion engine at least one rotatable and axially secured rocker arm is arranged, wherein the rocker arm fixed to a camshaft (4 Seating cam group is associated with a Kleinhub- and a Großhubnocken, wherein means for axial displacement of the sliding axis (3) are arranged in a Vorstellposition and in a reset position, and the rocker arm for acting on an underlying gas exchange valve in the Vorstellposition under one of the Kleinhub - And Großhubnocken and in the reset position under the other of the small stroke and Großhubnocken is arranged, wherein the means for axial displacement of the sliding axis (3) a camshaft fixed groove piece (6) with an axial Verschiebenutprofil (7), one the sliding axis (3) transversely penetrating locking pin (8) for Eingri in the sliding groove profile (7), a holding block (10, 12), and an actuator (11) on the holding block, wherein an actuator pin (13) is in contact with another end (14) of the locking pin (8) for its optional Displacement in the Verschiebenutprofil (7), and wherein the holding block has a guide slot (22) for the locking pin (8), which provides the sliding axis (3) at the same time stops for compliance with the Vorstellposition and return position and an anti-rotation. It is further provided that a deflection device (15) is arranged between the actuator pin (13) and the locking pin (8), and that the deflecting end (19) of the actuator pin (13) with a first end (16) and the deflection end ( 14) of the locking pin (8) with a second end (17) of the deflecting device (15) are non-positively connected.

Description

The invention relates to a variable valve train for an internal combustion engine, with a longitudinally slidable in a carrier head sliding axis on which each cylinder of the internal combustion engine at least one rotatable and axially secured rocker arm is arranged, wherein the rocker arm fixed to a camshaft seated cam group with a Kleinhubnocken and a Großhubnocken is assigned, wherein means for axial displacement of the sliding axis are arranged in a Vorstellposition and in a reset position, and the rocker arm to act on an underlying gas exchange valve in the Vorstellposition under one of the small stroke cam and Großhubnocken and in the reset position among the other Kleinhubnocken and Großhubnocken is arranged, wherein the means for the axial displacement of the sliding axis a camshaft fixed groove piece with at least one axial Verschiebenutprofil, a transverse to the sliding axis An actuator pin of the actuator is in at least indirect contact with another end of the locking pin for its selective displacement in the Verschiebenutprofil of the Nutstücks, and wherein a locking pin for engagement of its free end in the Verschiebenutprofil, an internal combustion engine-fixed holding block, and an actuator on the holding block the holding block or another engine-resistant component has a guide slot for the locking pin, which offers the sliding axis at the same time stops for compliance with the Vorstellposition and the return position and an anti-rotation.

The not pre-published DE 10 2015 217 914 A1 the applicant shows such a valve train with a sliding axis with a rocker arm, which is partially covered by a cladding region of a holding block. The support block is integral with upstanding walls of a carrier head supporting a camshaft and the slide axis. The holding block is located diametrically opposite a camshaft-fixed groove piece, which has a sliding groove profile. A jacket region of the holding block has a slot extending parallel to the sliding axis as part of a guide slot, wherein a bore of diameter of a width of the slot originates as a further component of the guide slot from the base of the slot at each of its axial ends. The holes are cut at their bottoms by a common central recess into which an actuator pin of an actuator protrudes. The Aktorstift is in permanent contact with a plate-like widened end of a locking pin which penetrates the sliding axis perpendicular to engage in a Verschiebenutprofil the Nutstücks.

For fixing a first setting position of the sliding axis of the locking pin is on its widened end on the bottom of one of the holes of the holding block, wherein it is disengaged from the sliding groove. For fixing a second actuating position of the sliding axis of the locking pin by means of actuation of the actuator and displacement of the Aktorstifts against the force of a return spring with its Nutstück the end facing into the Verschiebenutprofil einspurbar and at the same time with a cladding region at its other end in the aforementioned slot raised, so in that the locking pin displaces the sliding axis with the oscillating lever during further rotation of the camshaft to the respective other axial end of the oblong hole. The displacement groove profile has an ejection contour, via which the locking pin can be pressed into the other bore down to the bottom thereof.

The actuator is an electromagnetic linear actuator, wherein the actuator pin is aligned parallel to the locking pin in the sliding axis and in direct contact with the one end of the locking pin. In this known arrangement, the actuating direction of the actuator is perpendicular to the sliding axis and the camshaft. The position of the actuator is fixed and offers little adaptability to existing space conditions on the engine or on the carrier head. In addition, a relatively large Aktorhub for actuating the locking pin is required. The possible actuation path of the locking pin is rather small in comparison, whereby the outer diameter of the Nutstücks must be designed to be relatively large. Furthermore, it has been found that in this arrangement sealing problems can occur on the actuator.

The invention has for its object to improve a generic valve train for an internal combustion engine so that the disadvantages mentioned are eliminated and its design features lead to a reduction in manufacturing costs. In particular, a flexible arrangement of an actuator should be possible in the valve train.

The invention is based on the finding that a generic variable valve train can be installed more easily in an existing internal combustion engine if the installation location of individual components of the valve train is flexibly adaptable to the respective particular conditions. An actuator, which is used, according to an engine control, for shifting a sliding axle with rocker arms arranged thereon to provide a multi-stage valve lift variation of the intake valves and / or exhaust valves, is one such component essential to the adaptability of the valve train. Such a Actuator can be positioned differently than previously known, if the adjustment of the sliding axis by means of a Akthaneaufschlagung indirectly via a simple intermediate mechanism. Space problems can be avoided.

The invention is therefore based on a variable valve train for an internal combustion engine, with a longitudinally slidable in a carrier head sliding axis on which each cylinder of the internal combustion engine at least one rotatable and axially secured rocker arm is arranged, wherein the rocker arm fixed to a camshaft cam group associated with a small stroke cam and a Großhubnocken, wherein means for axial displacement of the sliding axis are arranged in a Vorstellposition and in a reset position, and the rocker arm to act on an underlying gas exchange valve in the Vorstellposition under one of the small stroke cam and Großhubnocken and in the reset position below the other of the small stroke cam and Großhubnocken is arranged, wherein the means for axial displacement of the sliding axis a camshaft fixed groove piece with at least one axial Verschiebenutprofil, the sliding axis transversely through an actuator pin of the actuator in at least indirect contact with another end of the locking pin for its selective displacement in the Verschiebenutprofil the Nutstücks, and wherein the holding block or another component fixed to a combustion engine has a guide slot for the locking pin, which at the same time offers stops for compliance with the advance position and the return position as well as an anti-rotation lock.

To achieve the object, it is provided in this variable valve train according to the invention that a deflecting device is arranged between the Aktorstift and the locking pin, and that the deflecting end of Aktorstiftes with a first end of the deflection and the deflection end of the locking pin with a second end the deflection are positively connected.

A carrier head is understood as meaning a cylinder head or a part of a cylinder head of an internal combustion engine.

By virtue of the described arrangement, the actuator for displacing the sliding axis can be positioned largely independently of the arrangement and orientation of the sliding axis with the oscillating lever or arms and the camshaft on the internal combustion engine. With a deflection device between the Aktorstift of the actuator and the locking pin for the sliding axis an extension of the design possibilities for positioning and orientation of the actuator to the internal combustion engine and the associated constructive degrees of freedom is achieved. The position of the actuator can be variably adapted to existing space conditions of a particular application. As a result, existing connection components on a carrier head of the internal combustion engine, such as intake ducts, cooling water pipes, mounting frame, etc., can be taken over unchanged or with slight changes, thereby reducing the manufacturing and assembly costs.

The actuator for acting on the locking pin can be designed as an electromagnetic actuator. Alternatively, the actuator can be actuated hydraulically or electrohydraulically.

According to a further embodiment of the invention may be provided with respect to the deflection device, that the deflection device is designed as a lever which is rotatably mounted between its two ends, that the first end of the lever has a first spherical functional surface, which is in contact with a contact surface of one end located the Aktorstifts, and that the second end of the lever has a second spherical functional surface, which is in contact with a contact surface of one end of the locking pin.

Accordingly, by means of a lever, a frictional connection of the Aktorstifts is made to the recorded in the sliding axis locking pin. Such a lever arrangement enables a positioning of the actuator, in which actuator pin and locking pin no longer need to be arranged linearly one behind the other as before.

The lever may be received in the carrier head and there rotatably supported and fixed between the lever ends. The closure and sealing of the lever to the outside can be done for example via a simple cover on the carrier head. The carrier head can be adapted for receiving the lever and the lid with little effort.

The geometric shape and detailed design of the lever can be advantageously adapted to a particular application or to design specifications of the internal combustion engine. In particular, a force application angle of the actuator pin on the first functional surface of the associated lever end can be varied by a convex design of this functional surface. Likewise, a force application angle between the second functional surface on the other end of the lever and the locking pin by a likewise spherical training this functional area can be varied. This allows, for example, an oblique orientation of the actuator to the carrier head, wherein the arrangement angle is arbitrary in a wide range of angles.

By positioning a pivot point or bearing point on which the lever is rotatably mounted and thereby determined ratio of the lengths of the two outgoing from this pivot lever arms, as well as the choice of the absolute lengths of the two lever arms, according to the known lever law, the lever ratio and the Lever forces are adapted to the respective requirements with respect to a stroke of the actuator pin and a stroke of the locking pin and a required actuating force.

In particular, the actuator stroke required for actuating the locking pin can be reduced and the locking stroke required for engagement of the locking pin in the sliding groove profile of the groove piece can be increased by a suitable lever transmission. By a larger stroke of the locking pin, the outer diameter of the Nutstücks may optionally be reduced because the locking pin is a larger actuation path until it engages in the Verschiebenutprofil available. The Nutstück thus requires a smaller space and can be advantageously reduced in weight.

In order to achieve a particularly high wear resistance of the lever, the contact surfaces on the lever can additionally be treated, for example heat treated, hardened or coated. Also, the frictional forces between the surfaces in contact with each other can be reduced in this way.

According to a further embodiment of the invention it can be provided that the actuator is arranged laterally and vertically on the internal combustion engine.

By a vertical arrangement of the actuator laterally on the internal combustion engine, a sealing unit, for example in the case of an electromagnetic actuator for sealing the actuator or its switching part against an inadmissible oil inlet, be simplified or possibly omitted entirely. Due to a possible omission of a movement of the Aktorstifts inhibiting seal member, the Aktorstift may optionally achieve a higher adjustment speed, which advantageously reduces the switching time of the actuator and can increase the switching frequency.

Finally, the invention also relates to a vehicle, such as a motorcycle with a DOHC single-cylinder engine, with a valve train, which is constructed according to one of the device claims.

The increasingly stringent emission regulations and efforts for a low fuel consumption also require motorcycles or mopeds variable valve trains to demand variation of opening time, stroke length and opening and closing times of the gas exchange valves. The flexible arrangement of the actuator according to the invention allows such a valvetrain to be advantageously implemented in motorcycle engines or moped engines, even in very inexpensive variants. The internal combustion engine may in particular be a DOHC single-cylinder engine. Also, an OHC valve train or a 2V valve train can be formed according to the invention.

In a DOHC single-cylinder engine, for example, the inlet side of the valve train can be designed according to the invention in different variants. However, an outlet-side application or a two-sided application to both an intake camshaft and an exhaust camshaft is also possible. In internal combustion engines with multiple cylinders all cylinders can be supplied via a single sliding axle with a corresponding number of rocker arms. Alternatively, each cylinder can be assigned its own sliding axis.

The invention will be explained in more detail with reference to an embodiment shown in the accompanying drawing. In the drawing shows

1 a perspective view of a carrier head of an internal combustion engine with a valve drive built therein according to the invention, and

2 a longitudinal section through the carrier head with the valve train according to 1 ,

The 1 and 2 show a DOHC valve train 1 a one-cylinder 4V motorcycle internal combustion engine, in which an inlet side, that is two intake valves is designed to be variable in displacement by the use of different sized cam of a camshaft. Such a valve train 1 is in the aforementioned DE 10 2015 217 914 A1 described and must at this point will not be explained in detail. The disclosure of the DE 10 2015 217 914 A1 Rather, it also becomes the content of the following description. The description is therefore limited essentially to the further improvement of the known valve train with regard to an inventive positioning of an actuator in the carrier head 2 or cylinder head of the internal combustion engine.

Thus, in a carrier head 2 a longitudinally displaceable between an advance position and a return position sliding axis 3 arranged. According to the DE 10 2015 217 914 A1 are on the sliding axis 3 arranged two rocker arm, which are rotatable and axially fixed thereto. Each rocker arm is one fixed to a camshaft 4 seated cam group, each with a small stroke cam and a Großhubnocken assigned. The rocker arms are located, depending on the axial position of the sliding axis 3 below the high-lift cams or under the low-lift cams, and they act on the associated associated gas exchange valves to produce a long stroke or a small stroke of the gas exchange valves.

For shifting the sliding axis 3 in a Vorstellposition or in a reset position means are provided, which are described below. These include a camshaft-fixed, separate Nutstück 6 with an axial displacement groove profile 7 , which next to a drive wheel, not shown, on the camshaft 4 fixed or integrally formed with this. Furthermore, this includes the sliding axis 3 radially penetrating locking pin 8th to engage with its first end 9 in the move profile 7 , In 2 is the locking pin 8th out of engagement before the beginning of the Verschiebenutprofils 7 shown. In addition, one is the Nutstück 6 on the sliding axis 3 diametrically opposite holding block 10 present, one arm 12 has, at the free end of an electromagnetic actuator 11 is attached.

The actor 11 is not like that, though DE 10 2015 217 914 A1 known in back linear extension of the locking pin 8th arranged, but at the with the holding block 10 integrally connected, laterally outward on the carrier head 2 guided arm 12 so the actor 11 is arranged vertically aligned with respect to its actuating axis. For fixing the actuator 11 on the arm 12 holding block 10 here is a screw connection 5 intended.

The actor 11 has an axially movable actuator pin 13 on, which at energization of the actuator 11 out of this. The Aktorstift 13 is according to the arrangement and orientation of the actuator 13 in only indirect contact with a second, as a plate-like widening 23 executed end 14 of the locking pin 8th , For this purpose, according to the invention between the Aktorstift 13 and the locking pin 8th one here as a lever 15 trained deflection arranged. About the lever 15 is the Aktorstift 13 indirectly frictionally permanently with the locking pin 8th in contact.

The lever 15 is between its two axial ends 16 . 17 rotatable on the carrier head 2 stored. A first end of the lever 16 is here as a first spherical functional surface 18 formed and is in contact with a contact surface 19 the free end of the actuator pin 13 , A second end of the lever 17 is as a second, also convex functional surface 20 formed and is in contact with a contact surface 21 at the widened, lever-side end 14 of the locking pin 8th , When energizing the actuator 11 becomes the linear movement of the actuator pin 13 by means of the lever 15 deflected into a corresponding linear movement of the locking pin 8th into the sliding axis 3 ,

The axial displacement of the sliding axis 3 takes place by means of a forced operation of the locking pin 8th in the displacement profile 7 the Nutstücks 6 upon rotation of the camshaft 4 , With a shift of the sliding axis 3 from the pre-position to the return position and vice versa, the locking pin 8th taken accordingly and with the sliding axis 3 shifted axially. The axial displacement of the locking pin 8th takes place in a guide setting 22 for the locking pin 8th , where the actor 11 briefly energized to the locking pin 8th in the lead setting 22 lift and engaged with the sliding groove profile 7 bring to. At the respective end position of the locking pin spurt 8th from the sliding groove profile 7 and is doing in a hole in the guide slot 22 lowered again, such that the sliding axis 3 is secured in the longitudinal direction and in the circumferential direction in the respective end position. It is in each axial position of the locking pin 8th this one with its contact surface 21 at its widened end 14 in contact with the facing functional surface 20 at the second end of the lever 17 of the lever 15 ,

The exact design of the guide slot 22 for the locking pin 8th and their function is analogous to DE 10 2015 217 914 A1 and therefore need not be further illustrated here, which is not the subject of the present invention.

LIST OF REFERENCE NUMBERS

1

 valve train

2

 Carrier head, cylinder head

3

 sliding axis

4

 camshaft

5

 screw

6

 groove piece

7

Sliding groove profile of groove piece 6

8th

 locking pin

9

First end of locking pin 8th

10

 holding block

11

 actuator

12

Arm of holding block 10

13

 actuator pin

14

Second end of locking pin 8th

15

 Deflection device, lever

16

First lever end 15

17

 Second end of the lever

18

Functional surface of the lever end 16

19

Deflection-side end of the locking pin 13 , lever-side contact surface

20

Functional area from the second end of the lever 17

21

Contact surface of locking pin 8th

22

Guide slot of locking pin 8th

23

Deflection side widening of the end 14 from locking pin 8th

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The 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

• DE 102015217914 A1 [0002, 0027, 0027, 0028, 0030, 0034]

Claims (4)

Variable valve train ( 1 ) for an internal combustion engine, with a longitudinally in a carrier head ( 2 ) axially displaceable sliding axis ( 3 ), on the per cylinder of the internal combustion engine, at least one rotatable and axially secured rocker arm is arranged, wherein the rocker arm fixed on a camshaft ( 4 ) seated cam group is associated with a small stroke cam and a Großhubnocken, wherein means for axial displacement of the sliding axis ( 3 ) are arranged in a Vorstellposition and in a reset position, and the rocker arm is arranged to act on an underlying gas exchange valve in the Vorstellposition under one of Kleinhubnocken and Großhubnocken and in the reset position under the other of the small stroke cam and Großhubnocken, wherein the means for axial displacement the sliding axis ( 3 ) a camshaft-fixed groove piece ( 6 ) with at least one axial displacement groove profile ( 7 ), one the sliding axis ( 3 ) transversely penetrating locking pin ( 8th ) to engage its free end ( 9 ) into the displacement profile ( 7 ), a combustion engine fixed holding block ( 10 . 12 ), as well as an actuator ( 11 ) on the holding block ( 10 . 12 ), wherein an actuator pin ( 13 ) of the actuator ( 11 ) in at least indirect contact is with another end ( 14 ) of the locking pin ( 8th ) for its optional transfer to the shift profile ( 7 ) of the Nutstücks ( 6 ), and wherein the holding block ( 10 . 12 ) or another component fixed to a combustion engine, a guide slot ( 22 ) for the locking pin ( 8th ), which of the sliding axis ( 3 ) at the same time provides stops for compliance with the advance position and the return position and an anti-rotation, characterized in that between the Aktorstift ( 13 ) and the locking pin ( 8th ) a deflection device ( 15 ), and that the deflecting end ( 19 ) of the Aktorstiftes ( 13 ) with a first end ( 16 ) of the deflection device ( 15 ) and the deflecting end ( 14 ) of the locking pin ( 8th ) with a second end ( 17 ) of the deflection device ( 15 ) are positively connected. Valve gear according to claim 1, characterized in that the deflection device as a lever ( 15 ) formed between its two ends ( 16 . 17 ) is rotatably mounted, that the first lever end ( 16 ) a first spherical functional surface ( 18 ) which is in contact with a contact surface ( 19 ) of one end of the actuator pin ( 13 ), and that the second lever end ( 17 ) a second spherical functional surface ( 20 ) which is in contact with a contact surface ( 21 ) of an end ( 14 ) of the locking pin ( 8th ) is located. Valve gear according to claim 1 or 2, characterized in that the actuator ( 11 ) is arranged laterally and vertically aligned with the internal combustion engine. Vehicle, such as motorcycle with a DOHC single-cylinder engine, with a valvetrain ( 1 ), which is constructed according to one of the device claims.

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