DE102018113802A1 - Variable valve train of a combustion piston engine - Google Patents

Abstract

The invention relates to a variable valve train (2) of a combustion piston engine, with at least two gas exchange valves (8) having the same function per cylinder whose valve lift is predetermined by at least one cam (6) of a camshaft (4) and by means of a switchable cam follower (12, 12 '). ) by an axial displacement of a guided in a transverse bore and with an outer portion (22, 22 ') from this projecting switching pin (20, 20') selectively switched off or to another Hubverlauf is switchable, wherein the shift pin formed as spring plates connecting elements (44 ) are in actuating connection with an elongated switching means (56) which is arranged parallel to the camshaft (4) and by means of an actuator against the restoring force of a spring element from a rest position into a switching position is longitudinally displaceable. In addition, it is provided that the switching pins (20, 20 ') of at least two adjacent rocker arms (12, 12'), the functionally identical gas exchange valves (8) of the same cylinder are assigned to protrude on sides facing each other from the rocker arms and at their outer ends ( 24, 24 ') via an actuating connection (42, 76) are axially positively connected with each other and with a common spring plate (44).

Description

The invention relates to a variable valve train of a combustion piston engine, with at least two gas exchange valves the same function per cylinder, the valve lift each predetermined by at least one cam of a camshaft and by means of a switchable cam follower by an axial displacement of a guided in a transverse bore and with an outer portion of this projecting shift pin selectively switched off or switchable to another stroke course, the shift pin of the cam followers are formed as spring plates connecting elements with an elongated switching means in actuator connection, which is arranged parallel to the camshaft and longitudinally displaceable by means of an actuator against the restoring force of a spring element from a rest position to a switching position ,

Under the elongated switching means is preferably a, for example, by punching or laser cutting out of a steel plate separated flat sheet metal rail to be longitudinally movably guided in slot-shaped guide openings of the cylinder head.

If the valve lift of gas exchange valves of a Verbrennungskolbenmotors are selectively switched off or switched over switchable drag lever groupwise, so separate switching pressure lines with a respective switching valve and in an electromagnetic adjustment of the lever-internal coupling elements separate electrical switching lines are required for their hydraulic adjustment of the lever-internal coupling elements, the line branches each to are guided in the drag levers.

Since the arrangement of separate hydraulic switching pressure lines or electrical switching lines in a cylinder head of a combustion piston engine due to cramped space is relatively difficult and expensive, were by the applicant in the unpublished patent applications DE 10 2017 101 792 A1 and DE 10 2017 129 422 A1 already proposed several versions of a variable valve train in which the transferable valve lift of several functionally identical gas exchange valves can be switched off or switched by means of a single actuator. In these variable valve drives, the switchable drag lever on a purely mechanical switching operation and are each switched by an axial displacement of a guided in a transverse bore of the drag lever and with an outer portion of this projecting switching pin. The switching pin of the finger follower are formed as spring plates connecting elements with an elongated switching means in actuating connection, which is arranged parallel to the camshaft and longitudinally displaceable by means of a preferably designed as an electromagnet linear actuator against the restoring force of a spring element from a rest position to a switching position.

In the case of the valve drives mentioned above, a spring plate is provided between the elongated switching means and the switching pin of all switchable rocker arms, the arrangement of which, however, can be difficult and in some cases even impossible due to confined space conditions.

The present invention therefore an object of the invention to present a space-saving actuating connection between the elongated switching means and the respective switching pin of the switchable rocker arm for a variable valve train of a combustion piston engine of the type mentioned.

This object is achieved in conjunction with the features mentioned in the preamble of claim 1, characterized in that the switching pin of at least two adjacent rocker arms, the functionally identical gas exchange valves of the same cylinder are protruding on sides facing each other from the rocker arms and projecting at their outer ends over a Stellverbindung axially positively connected with each other and with a common spring plate.

Accordingly, the invention is based on a variable valve drive of a combustion piston engine, with at least two gas exchange valves of the same function per cylinder whose valve lift is predetermined by at least one cam of a camshaft and by means of a switchable cam follower by an axial displacement of a guided in a transverse bore and with an outer portion This projecting switching pin is selectively switched off or switchable to another Hubverlauf, the switching pin of the rocker arms are formed as spring plates connecting elements with an elongated switching means in actuator connection, which is arranged parallel to the camshaft and by means of an actuator against the restoring force of a spring element from a rest position into a Shift position is longitudinally displaceable.

The inventive combination of the switching pin of the two immediately adjacent rocker arms and their axial coupling with each other and with a common spring plate switching operation of the two Schlepphebei only via a single spring plate, whereby, especially when using several such adjusting compounds in the valve train of a Verbrennungskolbenmotors the number of the Components are reduced and space is saved. Since the drag levers are associated with the pairwise coupled shift pin gas exchange valves the same function of a cylinder, the relevant shift pins perform during operation of the internal combustion piston engine each simultaneous movements, so that the adjusting connections between the two switching pin and the associated spring plate can be made comparatively simple and inexpensive ,

As a basic principle of such a positioning connection is proposed that the switching pin are each provided at its axially outer end with an open end recess through which an end piece is formed, which is arranged with a center and with respect to the other switching pin arranged in each case rotated by 180 ° Inner side and a semicircular curved outside is reduced to half the cross section of the outer portion of the shift pin. In addition, the shift pins are arranged coaxially overlapping on the end pieces with adjoining inner walls and radially opposite each provided with a guide groove, via which the end pieces of the shift pin axially positively engage in at least one longitudinal guide opening in the lower end portion of the associated spring plate.

According to a further concretized first embodiment of this actuating connection is provided that the guide grooves of the two switching pins are each formed as arranged in the curved outer side of the end pieces half annular grooves, and that in the spring plate, a single guide opening is present, as a centrally disposed, longitudinal guide slot is formed, which engage on both sides adjacent edge webs each in an annular groove of an end piece of the shift pin.

By the engagement of the edge webs of the spring plate in the annular grooves of the end pieces of the shift pin on one hand, the shift pin of the drag lever axially positively connected to each other. On the other hand, thereby the spring plate axially fixed and longitudinally displaceable and hinged to the shift pin of the cam follower, whereby the occurring during operation of the internal combustion piston engine lifting and rotating movements of the shift pin can be easily compensated.

To facilitate assembly, it is preferably provided that the guide slot of the spring plate is provided at its lower end with a round mounting opening, which has a relation to the width of the guide slot enlarged diameter. As a result, the spring plate during assembly, for example, with the guide slot initially pushed axially beyond the tail in question on the shift pin of the first finger lever and withdrawn after assembly of the second finger lever until it engages in the annular grooves of both switching pin.

According to a second embodiment of the actuating connection according to the invention it is provided that the guide grooves of the two shift pins are each formed as arranged in the flat inner side of the end pieces radial grooves, and that in the spring plate two guide openings are provided, which are formed as parallel to each other and symmetrically arranged, longitudinal guide slots are, located between them center web engages on both sides in each case in a radial groove of an end piece of the shift pin.

By the engagement of the central web of the spring plate in the radial grooves of the end pieces of both switching pins, the switching pin of the rocker arms are axially positively connected with each other. In addition, thereby the spring plate axially fixed and longitudinally displaceable and hinged to the shift pin of the cam follower, whereby the occurring during operation of the internal combustion piston engine lifting and rotating movements of the shift pin can be easily compensated.

To facilitate assembly is preferably provided in this second embodiment that the guide slots of the spring plate are each provided at its lower end with a laterally Ausnehmenden semicircular mounting opening, which have a relation to the width of the guide slots enlarged radius. In this way, the spring plate can be pushed during assembly, for example, first with the associated first guide slot axially beyond the relevant end piece on the shift pin of the first drag lever and withdrawn after installation of the second drag lever until it engages in the radial grooves of the two shift pin.

• 1 einen Ventiltrieb eines Verbrennungskolbenmotors mit einer ersten Ausführungsform einer erfindungsgemäßen Stellverbindung in einer ausschnittsweisen perspektivischen Ansicht,
• 2 die Stellverbindung gemäß 1 in einer ausschnittsweisen perspektivischen Einzelteilansicht,
• 3 den weitgehend selben Ventiltrieb eines Verbrennungskolbenmotors mit einer zweiten Ausführungsform einer erfindungsgemäßen Stellverbindung in einer ausschnittsweisen perspektivischen Ansicht, und
• 4 die zweite Ausführungsform der Stellverbindung gemäß 3 in einer ausschnittsweisen perspektivischen Einzelteilansicht.

To further illustrate the invention, the drawing of an embodiment is attached. In this shows

• 1 a valve train of a combustion piston engine with a first embodiment of an inventive Stellverbindung in a fragmentary perspective view,
• 2 the actuator connection according to 1 in a fragmentary perspective item view,
• 3 the largely the same valve train of a combustion piston engine with a second embodiment of a control connection according to the invention in a fragmentary perspective view, and
• 4 the second embodiment of the actuator according to 3 in a fragmentary perspective item view.

In the perspective view of 1 is a variable valve train 2 a combustion piston engine having a plurality of cylinders arranged in series and at least two gas exchange valves 8th the same function per cylinder shown in detail, as far as it is necessary to explain the invention.

In the 1 illustrated two gas exchange valves 8th are assigned to a cylinder of the internal combustion piston engine and functionally identical, so that it can be either intake valves or exhaust valves. The two gas exchange valves 8th are together with functionally identical gas exchange valves another cylinder via associated switchable drag lever 12 . 12 ' in the present example, groups can be switched off. An associated camshaft 4 indicates the functionally identical gas exchange valves 8th each cylinder a cam 6 on, which have identical lifting heights and Hubverläufe.

With a rotation of the camshaft 4 become the Hubverläufe the cams 6 via the switchable drag levers 12 . 12 ' on the gas exchange valves 8th transfer. The switchable drag levers 12 . 12 ' are largely identical in construction and each comprise a frame-shaped outer lever 14 and a pivotally mounted in this arranged inner lever 16 , The outside levers 14 each have at one end a sliding surface for contact with the valve stem 10 the associated gas exchange valve 12 . 12 ' and at the other end a receptacle for the head of a housing side mounted support member 40 with integrated hydraulic lash adjuster.

The inner levers 16 are for tapping the associated cam 6 the camshaft 4 each with a designed as a rotatably mounted Abgriff tapping element 36 provided and two trained as a torsion springs pressure springs 38 . 38 ' towards the camshaft 4 loaded with a spring force. About one in a longitudinal bore 18 of the outer lever 14 mounted, spring-loaded coupling pin is the inner lever 16 each form-fitting with the associated outer lever 14 coupled. In the coupled state of the switchable rocker arms 12 . 12 ' is the stroke of the cam 6 the camshaft 4 on the gas exchange valves 8th transferred so that they are opened cyclically.

By an axial displacement in each case one in a transverse bore of the outer lever 14 guided and with an outer section 22 . 22 ' from this protruding shift pin 20 . 20 ' inwardly or outwardly, the respective coupling pin is pressed into a decoupling position, in which the respective inner lever 16 from the associated outer lever 14 is decoupled and when tapping the associated cam 6 in relation to the outer lever 14 compressed. In the decoupled state of the rocker arms 12 . 12 ' is the stroke of the cam 6 the camshaft 4 thus not on the gas exchange valves 8th transferred so that they remain closed. In the not pre-published DE 10 2017 129 423 A1 Such a switchable rocker arm is shown and described.

To initiate a force for switching the rocker arms 12 . 12 ' , by each of the inner lever 16 from the outside lever 14 decoupled and thus the stroke transmission of the associated cam 6 the camshaft 4 on the gas exchange valves 8th is interrupted, protrude the shift pin 20 . 20 ' on sides facing each other from the rocker arms 12 . 12 ' out and are at their outer ends 24 . 24 ' via a mechanical positioning connection 42 axially positive fit with each other and with a common spring plate 44 connected, which in turn with an elongated switching element 56 in a standby connection. In this elongated switching element 56 it is preferably a flat sheet metal rail, for example, cut out of a steel sheet by punching or laser cutting, which is longitudinally movably guided in slot-shaped guide openings of the cylinder head.

The elongated switching element 56 is parallel to the camshaft 4 arranged and by means of a preferably designed as an electromagnet linear actuator against the restoring force of a spring element by a switching movement in the in 1 by a directional arrow 64 specified switching direction from a rest position into a switching position longitudinally displaceable. The spring plate 44 is at its upper end section 46 rigidly on the elongated switching element 56 attached. For this purpose, the upper end portion 46 of the spring plate 44 right angle angled, and the spring plate 44 from above into a passage opening 60 in the elongated switching element 56 used. The angled end section 46 of the spring plate 44 lies on the upper outside 58 the elongate switching element 56 and is by means of a clinch connection 62 rigid with the switching element 56 connected.

From the detailed item view of the 2 in which the components shown there 20 . 20 ' . 44 are shown in the non-coupled state, go the structure and operation of the actuator connection 42 between the switching pins 20 . 20 ' the two rocker arms 12 . 12 ' and the spring plate 44 clearly visible. The shift bolts 20 . 20 ' have at their outer end 24 . 24 ' one end open recess 26 . 26 ' on, through each one tail 28 . 28 ' the shift pin 20 . 20 ' is formed, which with a centrally and with respect to the other switching pin 20 ' . 20 each turned by 180 ° trained flat inside 30 . 30 ' as well as a semicircular curved outside 32 . 32 ' on the half section of the outer section 22 . 22 ' the shift pin 20 . 20 ' is reduced. The shift bolts 20 . 20 ' are at their end pieces 28 . 28 ' with adjacent inner walls 30 . 30 ' arranged coaxially overlapping and in each case radially opposite one another with a guide groove 34 . 34 ' provided over which the tails 28 . 28 ' the shift pin 20 . 20 ' axially positive fit in a longitudinal guide opening 50 in the lower end portion 48 of the spring plate 44 intervention.

The guide grooves 34 . 34 ' the two switching pins 20 . 20 ' are present in each case as in the curved outer side 32 . 32 ' the tails 28 . 28 ' arranged circumferentially formed half-annular grooves. The guide opening 50 of the spring plate 44 is formed as a centrally disposed in the same, longitudinal guide slot, the adjacent edge webs on both sides 52 . 52 ' each in an annular groove 34 . 34 ' a tail 24 . 24 ' one of the two switching pins 24 . 24 ' intervention. Through this engagement of the edge webs 52 . 52 ' of the spring plate 44 in the annular grooves 34 . 34 ' the tails 28 . 28 ' the shift pin 20 . 20 ' are the shift pins 20 . 20 ' the rocker arm 12 . 12 ' axially positively connected with each other. In addition, this is the spring plate 44 axially fixed and longitudinally displaceable and articulated to the shift pin 20 . 20 ' the rocker arm 12 . 12 ' attached, whereby the occurring during operation of the internal combustion piston engine lifting and rotating movements of the shift pin 20 . 20 ' be easily balanced.

The guide slot 50 of the spring plate 44 is at its lower end with a round mounting hole 54 provided one opposite the width of the guide slot 50 having enlarged diameter. This allows the spring plate 44 during assembly, for example, with the guide slot 50 initially axially over the relevant tail 28 out on the shift pin 20 of the first rocker arm 12 deferred and after the installation of the second rocker arm 12 ' until it engages in the annular grooves 34 . 34 ' both switching pins 20 . 20 ' be withdrawn.

For switching the drag levers 12 . 12 ' becomes the elongated switching means 56 by means of the linear actuator in the switching direction 64 postponed. As a result, a corresponding force and the travel on the spring plate 44 on the shift pin 20 . 20 ' the rocker arm 12 . 12 ' transfer. If the inner lever 16 the rocker arm 12 . 12 ' are largely largely free of load, which when tapping the cams 6 through the tapping rollers 36 whose base circle is the case, the shift pin 20 of the first rocker arm 12 axially inward and at the same time the switching pin 20 ' of the second rocker arm 12 ' moved axially outwards. This will be the with the shift pin 20 . 20 ' in coupled connection coupling pin in each case by means of a suitable coupling mechanism (see DE 10 2017 129 423 A1 ) moved axially outward and as a result, the inner lever 16 from the outer levers 14 decoupled. If the inner lever 16 the rocker arm 12 . 12 ' are just loaded, the force and the travel are briefly by a resilient bending in the spring plate 44 saved, and the switching of the drag levers 12 . 12 ' takes place after further rotation of the camshaft 4 as soon as the inner lever 16 the rocker arm 12 . 12 ' are largely free of load.

The in a perspective view in 3 pictured variable valve train 2 ' a combustion piston engine differs from the valve train with a largely identical structure and the same operation 2 according to 1 only by another embodiment of the actuating connection 76 between the switching pins 20 . 20 ' the two rocker arms 12 . 12 ' and the spring plate 44 ,

From the sectional view of parts of 4 in which the components concerned here 20 . 20 ' . 44 are shown in the uncoupled state, go the structure and operation of this Stellverbindung 76 clearly visible. The two switching pins 20 . 20 ' are as before at their outer end 24 . 24 ' each with an open end recess 26 . 26 ' provided by each one end piece 72 . 72 ' the shift pin 20 . 20 ' is formed, which with a centrally and with respect to the other switching pin 20 ' . 20 each rotated by 180 ° arranged flat inside 30 . 30 ' and a semi-circular arched outside 32 . 32 ' on the half section of the outer section 22 . 22 ' of the shift pin 20 . 20 ' is reduced. The shift bolts 20 . 20 ' are at their end pieces 72 . 72 ' again with the adjoining inner walls 30 . 30 ' arranged coaxially overlapping and in each case radially opposite to a guide groove 74 . 74 ' provided over which the tails 28 . 28 ' the shift pin 20 . 20 ' axially positively in each case one of two parallel longitudinal guide openings 80 . 80 ' in the lower end portion 78 of the spring plate 44 intervention.

The guide grooves 74 . 74 ' the shift pin 20 . 20 ' are in this embodiment each as in the flat inside 30 . 30 ' the tails 72 . 72 ' formed trained radial grooves. And the guide holes 80 . 80 ' of the spring plate 44 are as formed parallel and symmetrically arranged, longitudinal guide slots, located between them center bar 82 both sides each in a radial groove 74 . 74 ' a tail 72 . 72 ' one of the switching pins 20 . 20 ' intervenes. Through the engagement of the center bar 82 of the spring plate 44 in the radial grooves 74 . 74 ' the tails 72 . 72 ' are the shift pins 20 . 20 ' the rocker arm 12 . 12 ' axially positively connected with each other. In addition, this is the spring plate 44 axially fixed and longitudinally displaceable and articulated to the shift pin 20 . 20 ' the rocker arm 12 . 12 ' attached, whereby the occurring during operation of the internal combustion piston engine lifting and rotating movements of the shift pin 20 . 20 ' be easily balanced.

In the second embodiment of the actuating connection 76 according to the 3 and 4 are the contact surfaces between the flanks of the radial grooves 74 . 74 ' the shift pin 20 . 20 ' and the central pier 82 of the spring plate 44 for geometric reasons larger than the contact surfaces between the flanks of the annular grooves 34 . 34 ' the shift pin 20 . 20 ' and the side bars 52 . 52 ' of the spring plate 44 at the Stellverbindung 42 according to the 1 and 2 , This leads in the second embodiment of the actuating connection 76 to a lower load and a lower wear of the shift pin 20 . 20 ' and the spring plate 44 at the respective contact surfaces.

The guide slots 80 . 80 ' of the spring plate 44 in the second embodiment according to the 3 and 4 are at their lower end each with a laterally ausnehmenden semicircular mounting hole 84 . 84 ' provided one opposite the width of the guide slots 80 . 80 ' have enlarged radius. This allows the spring plate 44 during assembly, for example, first with the associated first guide slot 80 axially over the tail in question 72 out on the shift pin 20 of the first rocker arm 12 deferred and after the installation of the second rocker arm 12 ' until it engages in the radial grooves 74 . 74 ' both switching pins 20 . 20 ' be withdrawn.

LIST OF REFERENCE NUMBERS

2, 2 '

Variable valve train

4

camshaft

6

cam

8th

Gas exchange valve

10

valve stem

12, 12 '

Switchable drag lever

14

external lever

16

internal lever

18

longitudinal bore

20, 20 '

switching pin

22, 22 '

Outer section

24, 24 '

Outer end

26, 26 '

recess

28, 28 '

tail

30, 30 '

inside

32, 32 '

outside

34, 34 '

Guide groove, ring groove

36

Tap element, grip roller

38, 38 '

Pressure spring, leg spring

40

supporting

42

adjustment link

44

Connecting element, spring plate

46

Top end

48

Lower end section

50

Guide opening, guide slot

52, 52 '

edge web

54

mounting hole

56

Switching means, sheet metal rail

58

Upper outside

60

Through opening

62

clinch connection

64

Directional arrow, switching direction

72, 72 '

tail

74, 74 '

Guide groove, radial groove

76

adjustment link

78

Lower end section

80, 80 '

Guide opening, guide slot

82

center web

84, 84 '

mounting hole

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 102017101792 A1 [0004]
• DE 102017129422 A1 [0004]
• DE 102017129423 A1 [0022, 0028]

Claims (4)

Variable valve train (2, 2 ') of a combustion piston engine, with at least two gas exchange valves (8) of the same function per cylinder whose valve lift is predetermined by at least one cam (6) of a camshaft (4) and by means of a switchable cam follower (12, 12') by an axial displacement of a guided in a transverse bore and with an outer portion (22, 22 ') from this projecting switching pin (20, 20') selectively switched off or switchable to another stroke course, the shift pin (20, 20 ') of the drag lever (12, 12 ') formed as spring plates connecting elements (44) with an elongated switching means (56) are in actuating connection, which is parallel to the camshaft (4) and longitudinally displaceable by means of an actuator against the restoring force of a spring element from a rest position to a switching position , characterized in that the switching pins (20, 20 ') of at least two adjacent rocker arms n (12, 12 '), the functionally identical gas exchange valves (8) are assigned to the same cylinder, protrude on sides facing each other from the finger levers (12, 12') and at their outer ends (24, 24 ') via a control connection (42; 76) are axially positively connected with each other and with a common spring plate (44). Variable valve train after Claim 1 , characterized in that the switching pins (20, 20 ') have at their respective outer end (24, 24') an open end recess (26, 26 '), through each of which an end piece (28, 28', 72, 72 ') is formed, which with a centrally and with respect to the other switching pin (20', 20) each rotated by 180 ° formed flat inner side (30, 30 ') and a semicircular curved outside (32, 32') on the half cross section of outer portion (22, 22 ') of the switching pin (20, 20') is reduced, and that the switching pins (20, 20) on the end pieces (28, 28 ', 72, 72') with abutting inner walls (30, 30 ') coaxially overlapping and each radially opposite to a guide groove (34, 34', 74, 74 ') are provided, with which the end pieces (28, 28', 72, 72 ') of the shift pin (20, 20') axially positively in at least one longitudinal guide opening (50; 80, 80 ') in the lower end portion (48, 78) of the spring plate (44) eingre ifen. Variable valve train after Claim 2 , characterized in that the guide grooves (34, 34 ') of the two switching pins (20, 20') in each case as in the curved outer side (32, 32 ') of the end pieces (24, 24') arranged half annular grooves are formed, and that in the spring plate (44) a single guide opening (50) is provided, which is formed as a centrally disposed, longitudinally oriented guide slot whose mutually adjacent edge webs (52, 52 ') respectively in an annular groove (34, 34') of an end piece (24 , 24 ') of one of the switching pins (24, 24') engage. Variable valve train after Claim 2 , characterized in that the guide grooves (74, 74 ') of the two switching pins (20, 20') in each case as in the flat inner side (30, 30 ') of the end pieces (72, 72') arranged radial grooves (74, 74 ') are formed, and that in the spring plate (44) has two guide openings (80, 80 ') which are formed as parallel to each other and symmetrically arranged, longitudinal guide slots whose located between them central web (82) on both sides in each case in a radial groove (74 , 74 ') of an end piece (72, 72') of one of the switching pins (20, 20 ') engages.

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