DE102008031311A1 - Switchable bucket tappets for a valve train of an internal combustion engine - Google Patents

Abstract

Proposed is a switchable tappet (1) for a valve train of an internal combustion engine, with a ring-like Nockenanlaufboden (2) having housing (3), from the outer edge (4) a shirt (5) and from the inner edge (6) a hollow cylindrical projection (7 ) projects with a bore (8) in which a to the housing (3) relatively axially movable inner part (9), wherein in a bore (11) of the inner part (9) a coupling means (12) is applied, which for a full valve lift sections with a driver surface (13) of the housing (3) is engageable, wherein the inner part (9) is shown substantially as a thin-walled, open on both sides pipe section bridged by a transverse web (15) with the bore (11) is, is provided as a coupling means (12) only a non-rotating and in the coupling direction via at least one compression spring (17) and decoupling via hydraulic means lozierbarer piston, the starting v on its coupling-side end (18), on whose upper side (19) with a section-wise flattening (20) is provided, on which he in the coupling case under the end face of the ring (7) of the housing (3) formed driving surface (13) displaceable is.

Description

Field of the invention

The The invention relates to a switchable bucket tappet for a valve train of an internal combustion engine, with a a ring-like cam starting bottom housing, from the outer edge of a shirt and from its inner edge a hollow cylindrical projection protrudes with a bore in which a extends to the housing relatively axially movable inner part, the underside of a system for a gas exchange valve immanent, wherein in a bore of the inner part a coupling agent is applied, the sections for a full valve lift with a cam surface of the housing in engagement can be brought and wherein between the housing and the inner part a lost-motion spring is clamped.

Background of the invention

Such a tappet goes out of the regarded as generic DE 44 92 633 C1 out. Its coupling mechanism is located immediately below the floor area. The skilled artisan will recognize that the prior art ram is constructed relatively complicated and thus its production proves to be unnecessarily costly. For example, the outer part in the bottom area is not formed substantially symmetrical, since below the annular bottom guide holes for the coupling piston are applied. Also, the inner part is unnecessarily massive and complicated. Due to the aforementioned massive design, the oscillating valve train masses are disadvantageously increased.

moreover are from the older state of the art solutions previously known, in which the one or more coupling piston in the coupling case in a frontally adjacent, all-round annular groove of each retract another component. The ring groove weakens for a Material and increases the other hand, the production cost. Possibly. is also to rake with unnecessarily long oil routes, which can have an adverse effect on the switching times.

Object of the invention

task The invention is therefore a bucket tappet of the aforementioned type, in which the cited disadvantages eliminated with simple means.

Solution of the task

According to the invention This object is achieved in that the inner part substantially shown as thin-walled, open on both sides pipe section is, bridged by a crosspiece with the bore is, as coupling means only a rotationally secured and in the coupling direction via at least one compression spring and in Decoupling via hydraulic means lozierbarer piston is provided, which, starting from its coupling-side forehead, to its upper side provided with a section-wise flattening is about which he is in the coupling case among the end Ring end of the approach of the housing trained driving surface is displaceable.

in principle It is also conceivable and intended, the inventive Measures for additional switchable valve train links like roller tappets or support elements to apply.

Consequently the above disadvantages are eliminated. The invention relates a so-called "single-piston lock," which is relatively simple is constructed and only has a low component requirement. Furthermore are by the arrangement of the coupling piston in the inner part of the oscillating Valve drive masses lowered and there are also no complex Measures required to a driving surface to create for the coupling piston, since the already existing end annular end of the approach is used.

Especially it is preferred if the tappet according to the invention is designed as a "Ausschaltstößel". Thus, only the housing has the bottom side with appropriate Be provided cam starting measures. The starting bottom on the housing can, but does not necessarily, have a convex shape in the direction of cam migration be.

By the substantially thin-walled, tubular formation the inner part is another contribution to lowering the mass made the tappet.

Possibly. Solutions are also conceivable and intended, in which on Coupling agent is dispensed with the flattening or in which the flattening, for example, slightly convex contouring o. Like. Has. This can go along with the driver surface At the base also, for example, crown-like design.

One Another essential component of the invention is that the piston is formed zweigestuft, wherein the first, coupling side Longitudinal section has a smaller diameter than its second coupling remote longitudinal section. So it is possible, an annular end on the coupling means between the Longitudinal sections as a pressure surface for hydraulic fluid form, which can be conducted in a pressure chamber formed there is.

According to a further concretization of the invention, the aforementioned pressure chamber over a simple supply line be supplied, which intersects the bore for the coupling means orthogonal or wind skew and "smooth" emanating from the outer shell of the inner part.

According to one further expedient development of the invention can the hole in the inner part of the coupling agent as stepped through-hole to be formed. This is manufacturing technology relatively cheap. It is the one-end investment of the compression spring, which the coupling agent according to the invention in the coupling direction shift (pressureless locked) a thin-walled ring part provided as a stop element in the second section of the bore. This can itself, seen in the direction of drilling to the outside, at one snapped into the hole circlip / snap ring or the like support. At the other end, the compression spring sits in a recess a coupling remote forehead of the coupling agent.

to better guidance of the aforementioned compression spring has the stop element, starting from its inner edge, extending in the direction of the piston Ring collar around which the compression spring is placed one end. advantageously, the aforementioned assembly is designed so that the compression spring at their remote coupling stop position, which by the stop element is determined, not going to block.

A coupling-sided stop position is by planting the ring front between the longitudinal sections of the coupling means to a demgemäßen ring stage given the bore.

alternative It is suggested that the hole for the coupling agent represent as a simple and unestablished blind hole. For education it is the first section of the smaller diameter bore suggested here, in this a separate ring member, for example Press, through which the coupling agent with its first Longitudinal section of smaller diameter extends and on which ring part on the inside, the coupling agent in the coupling case a plant finds. In Entkoppelrichtung is the movement of the coupling agent limited by the plant whose coupling remote forehead at a bottom of the blind hole.

When simple anti-rotation device for the piston as a coupling agent a ring member is proposed, which in an annular groove in the outer jacket the inner part extends, which annular groove on a height section the flattening of the coupling agent is applied. In the thus open Hole area is the ring part on the flattening and prevents This in a simple manner a rotation of the coupling agent. Alternatively, it is also conceivable and provided, other anti-rotation measures to use for the coupling agent. For example, you can also from the bore for the coupling means outgoing pins or flats etc. may be provided.

Further Subclaims relate to simple Zuleitmaßnahmen of hydraulic fluid in the pressure chamber in the inner part.

Therefore inside the case runs a thin-walled Sheet metal part (optionally also a plastic training is conceivable), which essentially follows its contour. The sheet metal part, starting from a passage for the hydraulic medium in the shirt, molded channels (riser channel, bottom-side radial bead, Axial). As preferably on annular grooves for oil supply is omitted, the housing is compared to his Surround construction provided with a simple anti-rotation and also the inner part opposite the Housing such that a "directed" feeder the hydraulic means for supply in the inner part possible is.

alternative This can also on the outer coat of the shirt and on the outer jacket of the inner part or the bore of the approach the housing corresponding annular grooves for hydraulic fluid be applied, so waived against rotation can.

Especially it is preferred, the tappets as so-called Shutdown ram form. Alternatively, the Cup tappets also in the area of its inner part be provided with a cam starting floor (separate or one-piece), so that a Hubumschaltung is possible.

Short description of the drawing

The Invention is suitably with reference to the drawing explained in more detail. Show it:

1 a first longitudinal section through a tappet according to the invention with trained as a blind bore hole in the inner part;

2 a cut after 1 , but rotated 90 ° and the

3 a sectional view similar to in 1 shown, but with a continuous bore in the inner part.

Detailed description the drawing

The figures reveal a switchable bucket tappet 1 for a valve train of an internal combustion engine. This consists of a housing 3 with a ring-like cam starting floor 2 , From an outer edge 4 of the starting floor 2 stands in cam-off direction a shirt 5 off, about the Tas senstößel 1 in an unillustrated recording of the internal combustion engine oscillating feasible.

From an inner edge 6 of the cam starting floor 2 goes a hollow cylindrical approach 7 out. This one has a hole 8th in which one opposite the housing 3 in the decoupling case relatively axially movable inner part 9 with his outer coat 38 is included. At a bottom 10 of the inner part 9 a gas exchange valve can be created.

As can also be seen, the inner part has 9 essentially a thin-walled and tubular design. It has a crossbar 15 in that after 1 a trained as a blind bore hole 11 is applied. Furthermore acts between the components 3 . 9 a not-to-describe Lost-motion spring 14 which a return / holding the housing 3 serves on the cam contour in the case of shutdown.

For coupling, a one-piston lock is used according to the invention. For this purpose is as a coupling agent 12 only a thick stepped piston provided. This consists, as well as from the 1 can be seen from a first longitudinal section 21 smaller diameter and a second longitudinal section 22 larger diameter. The coupling agent 12 is in the coupling direction via the force of a compression spring 17 displaceable, the one-sided against a reason 37 ( 1 ) of the bore 11 is supported. With its other end, the compression spring acts 17 against a reason of a recess 35 of the coupling agent 12 at the coupling remote forehead 30 ,

Furthermore, for the expert 1 to see that the first longitudinal section 21 of the coupling agent 12 through a hole of a separate ring part 36 is guided that over its outer jacket into the bore 11 for example, is pressed. The ring part 36 forms an "ring step" on its coupling remote side 27 , which is part of a pressure chamber 25 is, the coupling remote through the ring front 26 of the coupling agent 12 is limited.

Hydraulic fluid can be supplied via a supply line 41a which are roughly, as well as out 2 shows 90 ° to the hole 11 is employed. When pressure is applied to the pressure chamber 25 There is thus a shift of the coupling agent 12 in the Entkoppelrichtung (in the cam base circle), so that the housing 3 a Leerhubbewegung relative to the inner part 9 takes place and the gas exchange valve in question remains closed.

As shown, has the coupling agent 12 at the top 19 , starting from the coupling-side forehead 18 , a flattening 20 , Over this it engages under a driving surface 13 at the hollow cylindrical approach 7 of the housing 3 , This driver surface 13 is the end of the ring end of the approach 7 educated. Thus, separate measures to form a coupling surface for the coupling agent 12 be waived.

Furthermore, it is apparent from the drawing that the coupling agent 12 is provided with a simple anti-rotation. This is a ring element 40 applied at the height of the flattening 20 in an annular groove 39 in the outer jacket 38 of the inner part 9 runs.

To supply the hydraulic fluid: the shirt 5 has, how closer 2 shows a passage 42 , This communicates inside with a riser 43 , which in the aforementioned sheet metal part 41 on the inner jacket 44 of the shirt 5 is shaped. Bodenseitig goes the riser 43 in at least one radial bead 45 over, with the radial bead 45 radially inward with a downward axial channel 46 communicated. End is the axial channel 46 in fluid communication with a passage 48 in a hollow cylindrical approach 7 , Due to not shown nä forth rotation (pin longitudinal groove o. The like.) Between housing 3 and inner part 9 is the passage 48 always the supply line 41a across from. Thus, there is a relatively "direct" supply of hydraulic fluid, starting from the passage without production-technically elaborate annular grooves 42 in the shirt 5 to the supply line 41a in the inner part 9 ,

3 discloses an alternative embodiment of the bore 11 in the inner part 9 , This is shown here throughout and in turn has a coupling-side, first section 23 small diameter and a non-coupling second section 24 larger diameter. For one-end investment of the compression spring 17 is here in the second section 24 the bore 11 a funnel-like stop element 29 installed, which extends in borehfernferne direction over its outer edge area 31 on a circlip 32 supporting, in an annular groove 33 of the second section 24 runs.

Furthermore, it can be seen that from an inner edge of the stop element 29 a ring collar 34 goes out to the the compression spring 17 is placed in sections with their single-ended area for management purpose.

Also revealed 3 a rotation lock shown schematically 49 in the shirt 5 for the tappet 1 ,

It should be emphasized that the inner part 9 is simply tubular and thus makes a contribution towards lightweight construction and reduction of manufacturing costs.

For an even investment of the pre called Lost Motion Pen 14 at the radial beads (or the radial bead) 45 of the sheet metal part 41 in the floor area (cam starting floor 2 ) a simple ring is provided as a compensation piece.

1

tappets

2

Cam nose Floor

3

casing

4

outer edge

5

shirt

6

inner edge

7

hollow cylindrical approach

8th

drilling approach

9

inner part

10

bottom

11

drilling inner part

12

coupling means

13

entraining

14

Lost-motion spring

15

crosspiece

16

Not forgive

17

compression spring

18

forehead

19

top

20

flattening

21

first longitudinal section

22

second longitudinal section

23

first Section hole

24

second Section hole

25

pressure chamber

26

annular end coupling means

27

annular step drilling

28

outer sheath

29

stop element

30

paddock distant forehead

31

Outer edge region

32

Circlip / snap ring

33

ring groove

 34

gorget

35

recess

36

ring part

37

reason

 38

outer sheath inner part

39

ring groove

40

ring element

41

sheet metal part

41a

supply

42

passage

43

rising channel

44

inner sheath shirt

45

radial corrugation

46

axial

 47

outer sheath approach

48

passage

49

twist

50

ring

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 4492633 C1 [0002]

Claims (16)

Switchable bucket tappets ( 1 ) for a valve train of an internal combustion engine, with a ring-like cam starting floor ( 2 ) housing ( 3 ), from its outer edge ( 4 ) a shirt ( 5 ) and from its inner edge ( 6 ) a hollow cylindrical approach ( 7 ) with a bore ( 8th ) protrudes in the one to the housing ( 3 ) relatively axially movable inner part ( 9 ) whose underside ( 10 ) an installation for a gas exchange valve is intrinsic, wherein in a bore ( 11 ) of the inner part ( 9 ) a coupling agent ( 12 ) is applied, which for a full valve lift in sections with a driver surface ( 13 ) of the housing ( 3 ) is engageable and wherein between the housing ( 3 ) and the inner part ( 9 ) a lost-motion spring ( 14 ) is clamped, characterized in that the inner part ( 9 ) is shown substantially as a thin-walled, open on both sides pipe section of a transverse web ( 15 ) with the bore ( 11 ) is bridged, as a coupling agent ( 12 ) only a rotationally secured and in the coupling direction via at least one compression spring ( 17 ) and in Entkoppelrichtung via hydraulic means lozierbarer piston is provided, which, starting from its coupling-side end ( 18 ), at the top ( 19 ) with a section-wise flattening ( 20 ), over which he in the coupling case under the end of the annular end of the approach ( 7 ) of the housing ( 3 ) trained driving surface ( 13 ) is displaceable. Cup tappet according to claim 1, characterized in that the piston as coupling means ( 12 ) from a first, coupling-side longitudinal section ( 21 ) of a small diameter and a second, long distance section ( 22 ) of larger diameter, which longitudinal sections ( 21 . 22 ) in correspondingly complementary sections ( 23 . 24 ) of the bore ( 11 ), wherein the hydraulic fluid in a pressure chamber ( 25 ) in the hole ( 11 ) is guided axially between one of the longitudinal sections ( 21 . 22 ) of the coupling agent ( 12 ) connecting annular end ( 26 ) and an opposite annular step ( 27 ) between the respective sections ( 23 . 24 ) of the bore ( 11 ) and radially by an outer jacket ( 28 ) of the first longitudinal section ( 21 ) low diameter and the section ( 23 ) of the bore ( 11 ) is formed larger diameter. Cup tappet according to claim 2, characterized in that over abutment of the annular end ( 26 ) of the coupling agent ( 12 ) at the ring stage ( 27 ) of the bore ( 11 ) whose coupling position is determined. Cup tappet according to claim 2, characterized in that the bore ( 11 ) for the coupling agent ( 12 ) in the crosspiece ( 15 ) as a through hole with the two stepped sections ( 23 . 24 ) is executed ( 3 ). Cup tappet according to claim 4, characterized in that in the second section ( 24 ) of the bore ( 11 ) [larger diameter] a stop element ( 29 ) like a thin-walled ring part as a single-ended system for the compression spring ( 17 ), which at the other end against a remote forehead ( 30 ) of the coupling agent ( 12 ) acts. Cup tappet according to claim 5, characterized in that over abutment of the remote forehead ( 30 ) of the coupling agent ( 12 ) on the stop element ( 29 ) a decoupling position of the coupling agent ( 12 ). Cup tappet according to claim 5, characterized in that the ring part as a stop element ( 29 ) with its outer edge region remote from the coupling ( 31 ) on a retaining ring / snap ring ( 32 ) rests in an annular groove ( 33 ) of the second section ( 24 ) of the bore ( 11 ) with the larger diameter. Cup tappet according to claim 5, characterized in that the ring part as a stop element ( 29 ) with a collar extending from its inner edge ( 34 ) is provided which extends in the coupling direction and by the compression spring ( 17 ) is enclosed, wherein the remote forehead ( 30 ) of the coupling agent ( 12 ) with a recess ( 35 ) is provided, in which the compression spring ( 17 ) sitting at the other end. Cup tappet according to claim 2, characterized in that the bore ( 11 ) in the crosspiece ( 15 ) is designed as unestated blind bore, wherein the formation of the first section ( 23 ) of the bore ( 11 ) of smaller diameter a separate ring part ( 36 ) in the hole ( 11 ) is attached, through which the coupling agent ( 12 ) with its first longitudinal section ( 21 ) of smaller diameter ( 1 ). Cup tappet according to claim 9, characterized in that as a finite system for the compression spring ( 17 ) for shifting the coupling by means of ( 12 ) a reason ( 37 ) of the bore shown as a blind bore ( 11 ), wherein the compression spring ( 17 ) at the other end in a recess ( 35 ) in the remote forehead ( 30 ) of the coupling agent ( 12 ) runs. Cup tappet according to claim 1, characterized in that in the outer shell ( 38 ) of the inner part ( 9 ), on a height section of the flattening ( 20 ) of the coupling agent ( 12 ), an annular groove ( 39 ) with a ring element ( 40 ), which ring element ( 40 ) on the flattening ( 20 ) of the coupling agent ( 12 ) runs for anti-rotation purpose. Cup tappet according to claim 2, characterized in that the pressure chamber ( 25 ) from a direct supply line ( 41a ) through the crosspiece ( 15 ver which is roughly the bore ( 11 ) orthogonal cuts and "smooth" from the outer shell ( 38 ) of the inner part ( 9 ). Cup tappet according to claim 12, characterized in that inside the housing ( 3 ) a thin-walled sheet metal part ( 41 ), which essentially follows its contour, wherein the shirt ( 5 ) with a passage ( 42 ) is provided for the hydraulic means, with a riser channel ( 43 ) in the sheet metal part ( 41 ) on the inner shell ( 44 ) of the shirt ( 5 ) communicates which riser ( 43 ) with one or more bottom-side radial beads ( 45 ) in the sheet metal part ( 41 ), from which the hydraulic medium into an axial channel ( 46 ) in the sheet metal part ( 41 ) on the outer jacket ( 47 ) of the approach ( 7 ), which approach ( 7 ) at its bottom-removed section with a passage ( 48 ), to which the axial channel ( 46 ), which passage ( 48 ) radially inward directly of the supply line ( 41a ) is opposite. Cup tappet according to claim 1 or 13, characterized in that the inner part ( 9 ) opposite the housing ( 3 ) is secured against rotation. Cup tappet according to claim 1 or 13, characterized in that the tappet ( 1 ) with one of his shirt ( 5 ) protruding against rotation ( 49 ) is provided. Cup tappet according to claim 1, characterized in that the tappet ( 1 ) is shown as "Abschaltstößel" whose inner part ( 9 ) is available without cam contact.