DE102018115040A1 - Switchable rocker arm for a valve train of an internal combustion engine - Google Patents

Abstract

The invention relates to a switchable rocker arm for a valve train of an internal combustion engine with a primary lever (1) and a secondary lever (2) pivotally supported on the latter, the primary and secondary levers (1, 2) being shiftable for shifting through at least one in a bore (4) arranged coupling element (5) can be coupled, characterized in that a displaceably arranged actuating member (8) is provided in a transverse bore (7) intersecting the bore (4) and cooperates with the coupling element (5) for switching via a sliding guide (10) , The actuating member (8) being slidably guided through an opening (17) which is continuous in the transverse direction on the coupling element (6) and which forms at least one guide contour (33) on which the actuating member (8) is slidably guided

Description

Field of the Invention

The invention relates to a switchable rocker arm for a valve train of an internal combustion engine according to the kind defined in the preamble of claim 1.

Hydraulically switchable rocker arms or electromechanically switchable systems are known from the prior art. The latter are, for example, as in EP3149295 described, equipped with a rotating actuator shaft that interacts with the rocker arm for switching at the lever end on the support side.

Many engine manufacturers show little acceptance compared to purely hydraulically switchable valve train components and prefer mechanically switchable concepts. However, these are complex to build, in particular due to the large number of components, and require a large amount of installation space.

Summary of the invention

The invention is therefore based on the object of simplifying a switchable rocker arm of the aforementioned type with regard to its construction and making it inexpensive.

The object is achieved by the features of patent claim 1. Further advantageous embodiments result from the respective subclaims, the description and the drawings.

A switchable rocker arm for a valve train of an internal combustion engine with a primary lever and a secondary lever pivotally supported on it is proposed, primary and secondary levers for switching being connectable by at least one coupling element arranged displaceably in a bore. According to the invention, an actuating element is provided which is displaceably arranged in a transverse bore which intersects the bore and which cooperates with the coupling element for switching via a sliding guide. This enables the development of a locking mechanism which can be actuated by a linear actuator acting in the longitudinal direction of the cylinder head. This can act on the locking mechanism in the actuated state with as little friction as possible if the contact between the actuator and the locking mechanism is arranged as close as possible with respect to the pivot axis of the primary lever. The actuator is operatively connected to the actuator along its longitudinal axis parallel to the pivot axis. The coupling element arranged at an angle of 90 ° in the longitudinal direction of the lever can couple or decouple the primary and secondary levers by longitudinal displacement. In this way, a simply constructed locking mechanism for a switchable rocker arm, which is actuated transversely to the longitudinal axis of the lever, is made possible.

The power transmission between actuator and coupling element takes place via a sliding guide consisting of a link guide and / or control contours. The actuating element is reset by return spring means which comprise one or more return springs arranged inside the lever. In this way, the locking mechanism can be unlocked by the return spring means without force or locked in a kinematic reversal. In a particularly advantageous manner, the locking mechanism can be designed with the actuating element as the same part in both a powerlessly unlockable and a powerlessly lockable design.

It is furthermore particularly advantageous if the actuating member is slidably guided through an opening on the coupling element in the transverse direction which forms at least one guide contour on which the actuating member is slidably guided. In this way, in particular, the assembly of the actuator in the sliding guide with the coupling element can be made considerably easier.

list of figures

• 1 einen erfindungsgemäßen schaltbaren Schlepphebel für einen Ventiltrieb einer Brennkraftmaschine in einem ersten Ausführungsbeispiel,
• 2 eine geschnittene Teilansicht des Schlepphebels in einem ersten Betriebszustand,
• 3 eine perspektivisch geschnittene Teilansicht des Schlepphebels im ersten Betriebszustand,
• 4 bis 7 Einzelteilansichten des Verriegelungsmechanismus des Schlepphebels,
• 8 eine perspektivische Einzelansicht eines Verriegelungsmechanismus des Schlepphebels,
• 9 bis 12 geschnittene Teilansichten des Schlepphebels mit dem Verriegelungsmechanismus in verschiedenen Montagezuständen.

Further features of the invention result from the following description and from the drawings, in which an embodiment of the invention is shown in simplified form. Show it:

• 1 a switchable rocker arm according to the invention for a valve train of an internal combustion engine in a first embodiment,
• 2 2 shows a sectional partial view of the rocker arm in a first operating state,
• 3 2 shows a perspective sectional view of the rocker arm in the first operating state,
• 4 to 7 Component views of the locking mechanism of the rocker arm,
• 8th a perspective view of a locking mechanism of the rocker arm,
• 9 to 12 sectional partial views of the rocker arm with the locking mechanism in different assembly states.

Detailed description of the drawings

In 1 to 3 a mechanically switchable rocker arm for a valve train of an internal combustion engine is shown as an example. The rocker arm consists of a so-called primary lever 1 and a so-called secondary lever which is pivotally supported on this 2 , The rocker arm is at a lever end region of the primary lever on the support side 1 on the underside of the lever with a spherical support surface 3 can be pivotally supported via a support element (not shown) on the internal combustion engine, in particular on a cylinder head thereof. At a valve-side lever end region, the rocker arm has at least one valve contact surface on the lever underside for actuating at least one gas exchange valve of the internal combustion engine. A locking mechanism is located in a housing-like section on the lever end area on the support side 4 integrated. This includes one in a hole 5 Coupling element arranged to slide in the longitudinal direction of the lever 6 that with a stepped coupling end 7 with the secondary lever 2 in the non-swung basic position of the primary and secondary lever 1 . 2 can be coupled ( 2 and 3 ). The switchable rocker arm is preferably constructed according to the so-called primary-in concept.

The hole in one 5 cross hole intersecting at an angle of 90 ° 8th is an actuator 9 against the spring force of spring means 10 slidably guided. The actuator 9 works via a sliding guide 11 with the coupling element 5 together. coupling element 6 and actuator 8th are designed in one piece as cylindrical bolts and can be moved along their respective longitudinal axes. Coupling element is also conceivable 6 and actuator 9 to be carried out in several parts. The actuator 9 is close to the pivot axis on the support surface 3 of the primary lever 1 or the rocker arm and axially parallel to the pivot axis. It is with the outside diameter at the inside diameter of the cross hole 8th led and protrudes with a stepped end 12 from the cross hole 8th out, on which an actuator, not shown, in particular electromechanical, can engage with an actuating force, as a result of which the actuating member 9 along its longitudinal axis in the cross hole 8th is slidable into it. The actuator works against the spring force of the other end 13 of the actuator 9 interacting spring means 10 , These are formed by a helical compression spring, which with the outer diameter on the inner diameter of the cross hole 8th led and with one end at the end 13 of the actuator 9 and with the other end at one in the cross hole 8th are secured in an annular groove on the inner diameter of the circlip.

The actuator 9 is on the outside diameter of an end section 14 on the top and bottom with oppositely aligned plane-parallel surfaces 15 . 16 flattened ( 4 and 5 ). On the coupling element 6 is a transverse opening 17 intended ( 6 and 7 ) in which the actuator 9 with the flattened end section 14 passed through and with the end 13 at the front through the spring means 10 in the cross hole 8th is supported in the direction of displacement ( 8th . 2 and 3 ). The opening 17 is designed like a window with a rectangular longitudinal profile and extends in the direction of displacement of the coupling element 6 over the entire displacement path. It is finished 7 of the coupling element 6 executed open. Corresponding to the plane-parallel surfaces 15 . 16 at the end section 14 of the actuator 9 are in the opening 17 of the coupling element 6 opposite plane-parallel surfaces on the top and bottom 18 . 19 educated ( 6 to 8th ). coupling element 6 and actuator 9 are in the opening 17 on the surfaces 18 . 19 or on the surfaces 15 . 16 guided against each other against rotation. The anti-rotation device ensures an exact position assignment or alignment of a coupling surface formed at the offset coupling end 20 of the coupling element 5 to a plant or driver area 21 at the free end of the secondary lever 2 guaranteed in the event of a coupling. At the same time, the alignment of attack surfaces as an assembly aid at the free end on the actuator side 12 of the actuator 9 ensured.

The actuator 9 has a larger outer diameter spring-side end portion 22 and an actuator-side end section having a smaller outer diameter 24 on. The actuator 9 is with the outer diameter of the spring-side end portion 22 on the inside diameter of the spring-side end section 23 the cross hole 8th guided. In contrast, it is with the actuator-side end section having the smaller outside diameter 24 with slight play compared to the inner diameter of the actuator-side end section 25 the cross hole 8th arranged. The spring-side end section 22 of the actuator 9 is through a ring heel 26 limited to which the actuator-side end section 24 immediately connects.

The sliding guide 11 has one at the flattened end portion 14 of the actuator 9 formed leadership backdrop 27 and one with the coupling element 6 associated leader 28 on that in the leadership backdrop 27 engages and slidable in this between an open end 34 and a closed end 30 the same is led. The leadership backdrop 27 is as one at the flattened end section 14 continuous slot between top and bottom and can alternatively be designed as a groove or as another depression. The slot 27 is on a flattened part of the spring-side end portion 22 executed and goes from the end of the ring heel 26 out. At the flattened end section 14 is through the slot 27 one with the coupling element 6 connected pin or a needle as a guide member 28 passed vertically ( 2 and 3 such as 6 to 8th ) The pencil 28 is the opening in one 17 and the areas 18 . 19 vertical cutting through hole 29 arranged and closes with its ends flush with the outer diameter of the coupling element 6 from. The power transmission between the actuator 9 and coupling element 6 is done via the pen 28 by the guide in the slot 27 the displacement movement of the actuator 9 in a displacement of the coupling element aligned by 90 ° to this 6 implemented for switching.

The slot 27 goes with the open end 34 from the ring heel 26 from the front and is at one end 30 closed. It runs in relation to the longitudinal axis 31 of the actuator 9 angled obliquely in the direction of the displacement axis of the coupling element 6 to the coupling end 7 inclined towards it. The slot 27 is with the closed end 30 to the spring end 13 back and forth with the open end 34 to the actuator end 12 aligned. When the actuator is moved 9 is the pen 28 with its outer diameter on the parallel opposite side walls of the slot 27 slidably guided.

At the closed end of the opening 17 is a flat side surface 32 executed, the plan-parallel on the top and bottom surfaces 18 . 19 combines. In the transition at the bottom between the side surface 32 and the area 19 is a guiding contour 33 intended. This is carried out in a particularly advantageous manner such that when the actuator is displaced 9 with the flattened section 36 of the spring end portion 22 into the opening 17 into it, this with the outer diameter on the guide contour 33 is led so that the leader 28 or the relevant pen automatically at the open end 34 the leadership backdrop 27 or automatically threading into the relevant slot. The guide contour 33 is designed as a chamfer here. As an alternative or in addition, it is also possible to use a guide contour of this type 33 at the transition at the top between the side surface 32 and the area 18 provided.

In the in 2 shown initial state is the pen 28 at the closed end 30 of the slot 27 , wherein the coupling element 6 with its coupling end 7 at the coupling end of the hole 5 is pushed out and with the coupling surface 20 on the system or driver surface 21 at the free end of the secondary lever 2 is applied. This makes the primary and secondary levers 1 . 2 coupled and the rocker arm is switched to the so-called locking state ( 3 ).

By actuating the actuator and moving the actuator 9 in the cross hole 8th against the spring force of the spring means 10 becomes the pen 28 to the open end 34 of the slot 24 on the paragraph 26 performed, which makes that with the pen 28 connected coupling element 6 with the coupling end 7 back into the hole 5 is moved into it. Thereby, primary and secondary levers 1 . 2 decouples and the rocker arm is switched to the so-called unlocked state.

For coupling primary and secondary levers 1 . 2 the actuator is switched off and by the spring force of the preloaded spring means 10 the actuator 9 reset and with the actuator end again out of the cross hole 8th pushed out ( 2 and 3 ). This will make the pen 28 back to the closed end 29 of the slot 27 led, the coupling element 6 with the secondary lever 2 coupled and the rocker arm switched to the locked state. In this way, the rocker arm is the spring force of the spring means 10 Can be locked without power so to speak.

9 to 12 show the assembly of the locking mechanism 4 on the support-side lever end area of the primary lever 1 , According to 8th is the coupling element 6 in the hole 5 inserted so that the opening 17 with the cross hole 8th flees ( 9 ). The actuator can 9 with the actuator end 12 in the spring-side end section 23 the cross hole 8th inserted and with the actuator-side end section 24 through the opening 17 on the coupling element 6 be performed. Here the actuator dips 9 with the spring-side end section 22 in the spring-side end section 23 the cross hole 8th one and is with the outside diameter on the inside diameter of the latter in the cross hole 8th guided ( 10 ). The end section on the actuator side 24 of the actuator 9 is in the actuator end section 25 the cross hole 9 postponed. Moving the actuator further 9 with the leadership backdrop 27 or the slot on the flattened section 36 of the spring end portion 22 into the opening 17 ( 11 ). The actuator engages 9 with the outer diameter of the spring-side end section 22 on the guide contour 33 in the opening 17 of the coupling element 6 on. At this the actuator 9 guided in such a way that the guide member in the event of further displacement 28 or the pen at the open end 34 of the slot 27 is automatically threaded ( 11 and 12 ). In a particularly advantageous manner, the assembly of the actuator can 9 in the sliding guide 11 with the coupling element 6 be made considerably easier.

The primary lever 1 is designed here as an outer lever, which is the secondary lever 2 at least partially as an inner lever ( 1 ). Primary and secondary lever 1 . 2 each have, for example, side walls on the longitudinal sides, the side walls of the secondary lever being in the non-pivoted basic position 2 the side walls of the primary lever 1 lie parallel, at least in sections. Between the side walls of the secondary lever 1 . 2 a cam roller is arranged, by means of which a cam stroke movement can be tapped from a camshaft (not shown) on the upper side of the lever.

The cross hole 7 with the actuator arranged in it 8th are cylindrical housing sections arranged transversely to the longitudinal axis of the lever 35 on the support-side lever end area of the primary lever 1 integrated ( 1 to 4 and 6 to 14 ). On the outside diameter of the housing sections 35 is a torsion spring coaxially attached as return spring means, the primary and secondary levers 1 . 2 pretension to the non-swung basic position.

LIST OF REFERENCE NUMBERS

1

primary lever

2

secondary lever

3

bearing surface

4

locking mechanism

5

drilling

6

coupling element

7

The End

8th

cross hole

9

actuator

10

spring means

11

sliding guide

12

The End

13

The End

14

end

15

area

16

area

17

opening

18

area

19

area

20

coupling surface

21

entraining

22

end

23

end

24

end

25

end

26

annular shoulder

27

Leadership, slot

28

Leader, pen

29

Through Hole

30

The End

31

longitudinal axis

32

side surface

33

guide contour

34

The End

35

housing section

36

part Of

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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.

Patent literature cited

• EP 3149295 [0002]

Claims (1)

Switchable rocker arm for a valve train of an internal combustion engine with a primary lever (1) and a secondary lever (2) pivotally supported on it, primary and secondary levers (1, 2) for switching by at least one coupling element (5) slidably arranged in a bore (4) ) can be coupled, characterized in that a displaceably arranged actuating member (8) is provided in a transverse bore (7) intersecting the bore (4) and interacts via a sliding guide (10) with the coupling element (5) for switching, the actuating member (8) is slidably guided through an opening (17) which is continuous in the transverse direction on the coupling element (6) and which forms at least one guide contour (33) on which the actuating member (8) is slidably guided.

Images