WO2009024390A1

WO2009024390A1 - Switchable tapper for a valve train of an internal combustion engine

Info

Publication number: WO2009024390A1
Application number: PCT/EP2008/058580
Authority: WO
Inventors: Mario Kuhl; Norbert Nitz; Sandra SCHÄFER; Lucia Hinkovska; Andreas Kufner
Original assignee: Schaeffler Kg
Priority date: 2007-07-20
Filing date: 2008-07-03
Publication date: 2009-02-26
Also published as: JP2010533819A; CN101755107B; DE102008031311A1; KR20100043186A; CN101755107A; KR101478860B1

Abstract

The invention relates to a switchable tappet (1) for a valve train of an internal combustion engine, with a housing (3), which has a ring-like cam stop bottom (2) and from the outer edge (4) of which a skirt(5) protrudes and from the inner wall (6) of which a hollow cylindrical shoulder (7) with a borehole (8) protrudes, in which an inner part (9), which can be moved axially relative to housing (3), extends, wherein, in a borehole (11) of the inner part (9), coupling means (12) are applied which, for a complete valve lift, can be brought sectionally into engagement with a dog surface (13) of the housing (3), wherein an inner part (9) is produced essentially as a thin-walled tube section, which is open at both ends and bridged by a transverse bridge (15) with the borehole (11), wherein, as coupling means (12), only a piston, secured against rotating, is provided, which can be located in the coupling direction over at least one compression spring (17) and, in the uncoupling direction, over hydraulic means, which piston, starting out from its face (18) on the coupling side, is provided at the upper side (19) with a sectional flattening (20), over which, in the coupling case, it can be shifted under the driver surface (13), which is constructed as an end side ring face of the shoulder (7).

Description

Name of the invention

Switchable bucket tappets for a valve train of an internal combustion engine

description

Field of the invention

The invention relates to a switchable bucket tappets for a valve train of an internal combustion engine, with a ring-like Nockenanlaufboden facing housing, from the outer edge of a shirt and from the inner edge of a hollow cylindrical projection protrudes with a bore in which a relatively axially movable to the housing inner part whose underside is a system for a gas exchange valve immanent, wherein in a bore of the inner part, a coupling agent is applied, which is partially engageable with a cam surface of the housing for a full valve lift and wherein between the housing and the inner part a Lost- Motion spring is clamped.

Background of the invention

Such a bucket tappet is apparent from the considered as generic forming DE 44 92 633 C1. 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 region is not formed substantially symmetrically, because below the annular shaped 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.

In addition, prior art solutions are previously known in which the one or more coupling pistons retract in a coupling case in a frontally adjacent, all-round annular groove of the other component. On the one hand, the annular groove weakens the material and on the other hand increases the production effort. Possibly. is also to rake with unnecessarily long oil paths, which can adversely affect the switching times.

Object of the invention

The object of the invention is therefore to provide a bucket tappet of the aforementioned type, in which the cited disadvantages are eliminated by simple means.

Solution of the task

According to the invention this object is achieved in that the inner part is substantially shown as a thin-walled, open on both sides pipe section which is bridged by a transverse web with the bore, wherein as a coupling means only a rotationally secured and in the coupling direction via at least one compression spring and decoupling via hydraulic means lozierbarer Piston is provided, which, starting from its coupling-side end, is provided on the upper side with a section-wise flattening over which it is displaceable in the coupling case under the end face as the annular end of the neck of the housing trained driving surface. In principle, it is also conceivable and intended to apply the measures according to the invention to further switchable valve train members such as roller tappets or support elements.

Thus, the above-described disadvantages are eliminated. The invention relates to a so-called "single-piston lock", which has a relatively simple construction and has only a low component requirement. [Os Außerdem] In addition, the arrangement of the coupling piston in the inner part lowers the oscillating valve train masses and no complicated measures are required to provide a driver surface for the coupling piston to create, since here the already existing end ring end of the approach is used.

It is particularly preferred for the tappet according to the invention to be designed as a "deactivating tappet." Thus, only the housing has to be provided with corresponding cam starting measures on the bottom side.

Due to the substantially thin-walled, tubular design of the inner part, a further contribution to lowering the mass of the tappet is made.

Possibly. Solutions are also conceivable and provided in which the flattening is dispensed with on the coupling means or in which the flattening has, for example, a slightly convex contouring or the like. This may be accompanied by the fact that the driver surface is formed on the neck, for example, crown-like.

Another essential component of the invention is that the piston is formed in two steps, wherein its first coupling-side longitudinal section has a smaller diameter than the second coupling-remote longitudinal section. Thus, it is also possible, an annular end on the coupling means between form its longitudinal sections as a pressure surface for hydraulic fluid, which is conductive in a pressure chamber formed there.

According to a further concretization of the invention, the aforementioned pressure chamber to be supplied via a simple feed line which intersects the bore for the coupling means orthogonal or askew and "smooth" emanates from the outer shell of the inner part.

According to a further expedient development of the invention, the bore tion in the inner part of the coupling means may be formed as a stepped through hole. This is manufacturing technology relatively cheap. In this case, a thin-walled ring part is provided as a stop element in the second section of the bore for the single-end system of the compression spring which is intended to displace the coupling means in the coupling direction (locked without pressure). This can, seen in the direction of the bore outwards, be supported on a snapped into the bore circlip or the like. Otherwise, the compression spring is seated in a recess of a coupling remote end of the coupling means.

For better guidance of the abovementioned compression spring, the stop element, starting from its inner edge, has a ring collar extending in the piston direction, around which the compression spring is placed one end. Advantageously, the aforementioned assembly is designed so that the compression spring does not go to block in its coupling remote stop position, which is determined by the stop element.

A coupling-side stop position is given by conditioning the annular end between the longitudinal sections of the coupling means to a demgemäßen ring stage of the bore.

Alternatively, it is proposed to represent the bore for the coupling agent as a simple and unestimated blind bore. To form the first section The bore of smaller diameter, it is proposed here, for example, in this press a separate ring member, through which the coupling means extends pelmittel with its first longitudinal section of smaller diameter and on which ring part inside the coupling means in the coupling case an attachment. In Entkoppelrichtung the movement of the coupling agent is limited by conditioning the coupling remote forehead at a bottom of the blind hole.

As a simple rotation for the piston as a coupling means, a ring member is proposed, which runs in an annular groove in the outer shell of the inner part, which annular groove is applied to a height portion of the flattening of the coupling means. In the thus open bore area, the ring member rests on the flattening and thereby prevents in a simple manner a rotation of the coupling means. Alternatively, it is also conceivable and intended to use other anti-rotation measures for the coupling agent. For example, out of 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.

Accordingly, runs inside the housing, a thin-walled sheet metal part (optionally, a plastic training is conceivable), which essentially follows its contour. Here, the sheet metal part, starting from a passage for the hydraulic fluid in the shirt, molded channels (riser channel, bottom-side radial bead, axial channel). Since it is preferably dispensed with ring grooves for oil supply, the housing should be provided with respect to its surrounding structure with a simple rotation and also the inner part relative to the housing such that a "directed" supply of hydraulic fluid to the supply line in the inner part is possible. Alternatively, corresponding annular grooves for hydraulic fluid may also be applied to the outer jacket of the shirt and to the outer jacket of the inner part or the bore of the attachment of the housing, so that it is possible to dispense with anti-rotation devices.

It is particularly preferred to design the bucket tappet as a so-called shutdown tappet. Alternatively, the bucket tappet in the region of its inner part with a cam starting floor (separately or in one piece) be provided, so that a Hubumschaltung is possible.

Short description of the drawing

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

Figure 1 shows a first longitudinal section through a tappet according to the invention with a blind bore formed in the inner part;

Figure 2 is a section of Figure 1, but rotated by 90 ° and the

Figure 3 is a sectional view similar to that shown in Figure 1, but with a continuously formed bore in the inner part. Detailed description of the drawing

The figures disclose 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 bottom 2. From an outer edge 4 of the starting bottom 2 is in the direction away from the cam from a shirt 5, over which the tappet 1 in an intake, not shown, of the internal combustion engine is oscillating feasible.

From an inner edge 6 of the cam base 2 is a hollow cylindrical projection 7 goes out. This has a bore 8, in which a relative to the housing 3 in the decoupling case relatively axially movable inner part 9 is received with its outer shell 38. On an underside 10 of the inner part 9, a gas exchange valve can be applied.

As can also be seen, the inner part 9 has a substantially thin-walled and tube-like design. It has a transverse web 15, in which, as shown in FIG. 1, a bore 11 designed as a blind bore is applied. Furthermore acts between the components 3, 9 a not-to-describe Lost-motion spring 14, which serves a return / holding the housing 3 on the cam contour in the case of shutdown.

For coupling, a one-piston lock is used according to the invention. For this purpose, only a thickness-graduated piston is provided as the coupling means 12. This consists, as can be seen from the figure 1, of a first longitudinal section 21 of smaller diameter and a second longitudinal section 22 of larger diameter. The coupling means 12 is displaceable in the coupling direction by the force of a compression spring 17 which is supported at one end against a base 37 (FIG. 1) of the bore 11. With its other end, the compression spring 17 acts against a bottom of a recess 35 of the coupling means 12 at the coupling remote end 30th Furthermore, it can be seen by the person skilled in the art from FIG. 1 that the first longitudinal section 21 of the coupling means 12 is guided through a bore of a separate annular part 36, for example, being pressed into the bore 11 via its outer jacket. The ring member 36 thus forms an "annular step" 27 on the coupling-remote side thereof, which is part of a pressure chamber 25 which is bounded by the annular end 26 of the coupling means 12.

Hydraulic means can be hauled through a supply line 41 a, which is approximately, as shown in Figure 2, 90 ° to the bore 11 employed. When pressurizing the pressure chamber 25 thus takes place a displacement of the coupling means 12 in the Entkoppelrichtung (in the cam base circle), so that the housing 3 performs a Leerhubbewegung relative to the inner part 9 and the gas exchange valve in question remains closed.

As shown, the coupling means 12 at its upper side 19, starting from the coupling-side end 18, a flattening 20. About this it engages under a driver surface 13 on the hollow cylindrical projection 7 of the housing 3. This driver surface 13 is formed as an end annular end of the projection 7. Thus, separate measures for forming a coupling surface for the coupling means 12 can be dispensed with.

Furthermore, it is apparent from the drawing that the coupling means 12 is provided with a simple rotation. For this purpose, a ring member 40 is applied, which extends at the level of the flattening 20 in an annular groove 39 in the outer casing 38 of the inner part 9.

For supplying the hydraulic means: The shirt 5 has, as shown in more detail in Figure 2, a passage 42. This communicates internally with a riser 43, which is formed in the above-mentioned sheet metal part 41 on the inner jacket 44 of the shirt 5. On the bottom side, the riser channel 43 merges into at least one radial groove 45, the radial bead 45 communicating radially inward with a downwardly leading axial channel 46. At the end, the axial channel 46 is in fluid Binding with a passage 48 in the hollow cylindrical projection 7. Due to the rotation not shown (pin longitudinal groove o. The like.) Between the housing 3 and inner part 9 of the passage 48 is always the supply line 41 a opposite. Thus, there is a relatively "direct" supply of hydraulic fluid, starting from the passage 42 in the shirt 5 to the supply line 41 a in the inner part 9 without manufacturing technically elaborate annular grooves.

Figure 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 portion 23 of small diameter and a second portion 24 of larger diameter remote from the coupling. For one-end investment of the compression spring 17 in this case in the second portion 24 of the bore 11, a funnel-like stop member 29 is installed, which is supported in borehungsferne direction over its outer edge portion 31 on a locking ring 32 which extends in an annular groove 33 of the second portion 24.

Furthermore, it can be seen that an annular collar 34 originates from an inner edge of the stop element 29, around which the compression spring 17 is laid in sections with its single-end region for the purpose of guiding.

In addition, Figure 3 discloses a rotation lock 49 shown schematically in the shirt 5 for the tappets. 1

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

For a uniform installation of the aforementioned lost motion spring 14 on the radial beads (or the radial bead) 45 of the sheet metal part 41 in the bottom area (cam start floor 2) a simple ring is provided as a compensation piece. List of reference numbers

1) Cup tappets

2) cam starting floor 3) housing

4) outer edge

5) shirt

6) inner edge

7) hollow cylindrical approach 8) bore approach

9) inner part

10) Base

11) bore inner part

12) coupling means 13) driving surface

14) Lost-motion spring

15) transverse web

16) not awarded

17) compression spring 18) forehead

19) top

20) Flattening

21) first longitudinal section

22) second longitudinal section 23) first section bore

24) second section hole

25) pressure chamber

26) Ring-end coupling agent

27) Ring step bore 28) Outer jacket

29) stop element

30) remote forehead 31) outer edge area

32) Circlip / snap ring

33) annular groove

34) ring collar 35) recess

36) annular part

37) Base

38) outer jacket inner part

39) annular groove 40) ring element

41) sheet metal part

41 a) Supply line

42) passage

43) Rising channel 44) Inner coat Shirt

45) radial bead

46) axial

47) Outer jacket approach

48) passage 49) anti-rotation

50) Ring

Claims

claims

1. Switchable tappet (1) for a valve train of an internal combustion engine, with a ring-like cam starting bottom (2) having housing (3), from the outer edge (4) a shirt (5) and of the inner edge (6) has a hollow cylindrical extension (7) with a hole

(8) projects, in which a to the housing (3) relatively axially movable inner part (9) extends, whose underside (10) immanent a system for a gas exchange valve, wherein in a bore (11) of the inner part

(9) a coupling means (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 which is bridged by a transverse web (15) with the bore (11), being used as coupling means ( 12) is provided only a non-rotating and in the coupling direction via at least one compression spring (17) and decoupling via hydraulic means zable piston which, starting from its coupling-side end (18), at the top (19) with a section-wise flattening (20) is provided, via which it is displaceable in the coupling case under the end face as the annular end of the projection (7) of the housing (3) formed Mitnehmer surface (13).

2. Cup tappet according to claim 1, characterized in that the

Piston as a coupling means (12) from a first, coupling-side longitudinal section (21) of low diameter and a second, remote from the coupling

Longitudinal section (22) on the other hand of larger diameter, which longitudinal sections (21, 22) in correspondingly complementary Ab- cut (23, 24) of the bore (11) extend, wherein the hydraulic fluid in a pressure chamber (25) in the bore (11) can be conducted axially between a longitudinal sections (21, 22) of the coupling means (12) connecting annular end ( 26) and an opposing annular step (27) between the respective sections (23, 24) of the bore (11) and radially through an outer sheath (28) of the first longitudinal section (21) of low diameter and the section (23) of the bore (11 ) is formed larger diameter.

3. Cup tappet according to claim 2, characterized in that over conditioning of the annular end (26) of the coupling means (12) on the annular step (27) of the bore (11) whose coupling position is determined.

4. cup tappet according to claim 2, characterized in that the bore (11) for the coupling means (12) in the transverse web (15) as a through hole with the two stepped portions (23, 24) is executed (Fig. 3).

5. Cup tappet according to claim 4, characterized in that in the second portion (24) of the bore (11) [larger diameter] a stop member (29) as a thin-walled ring member as a terminal AnIa- ge for the compression spring (17) is attached, which at the other end against a remote forehead (30) of the coupling means (12) acts.

6. cup tappet according to claim 5, characterized in that on investment of the remote forehead (30) of the coupling means (12) on the

Stop element (29) has a decoupling position of the coupling means (12) is fixed.

7. cup tappet according to claim 5, characterized in that the ring part as a stop element (29) with its remote from the outer edge region (31) on a circlip / snap ring (32) rests in an annular groove (33) of the second portion (24) the bore (11) extends with the larger diameter.

8. cup tappet according to claim 5, characterized in that the ring part is provided as a stop element (29) with an outgoing from its inner edge ring collar (34) which extends in the coupling direction and of the compression spring (17) is enclosed, wherein the remote forehead ( 30) of the coupling means (12) is provided with a recess (35) in which the compression spring (17) sits at the other end.

9. cup tappet according to claim 2, characterized in that the bore (11) in the transverse web (15) is designed as ungestufte blind bore, wherein the formation of the first portion (23) of the bore (11) of smaller diameter, a separate ring member (36) in the bore (11) is fixed, through which the coupling means (12) with its first longitudinal portion (21) of smaller diameter extends (Fig. 1).

10. Cup tappet according to claim 9, characterized in that as a finite abutment for the compression spring (17) for displacement of the coupling means (12) has a bottom (37) of the bore (11) shown as a blind bore, wherein the compression spring (17) the other end in a recess (35) extends in the coupling remote end (30) of the coupling means (12).

11. Cup tappet according to claim 1, characterized in that in the outer ßenmantel (38) of the inner part (9), on a height portion of the flattening (20) of the coupling means (12), an annular groove (39) with a ring element (40) , Which ring element (40) extends on the flattening (20) of the coupling means (12) for the purpose of preventing rotation.

12. Cup tappet according to claim 2, characterized in that the pressure chamber (25) of a direct supply line (41 a) through the transverse web (15) is supplied, which approximately orthogonal the bore (11) intersects and "smooth" from Outer jacket (38) of the inner part (9) goes out.

13. Cup tappet according to claim 12, characterized in that in the interior of the housing (3) a thin-walled sheet metal part (41) extends substantially following its contour, wherein the shirt (5) with a passage (42) for the hydraulic means is provided, which communicates with a riser channel (43) in the sheet metal part (41) on the inner jacket (44) of the shirt (5), which riser (43) with one or more bottom-side radial beads (45) in the sheet metal part (41) in combination is, from which the hydraulic fluid in an axial channel (46) in the sheet metal part (41) on the outer jacket (47) of the projection (7) is conductive, which approach (7) is provided at its bottom portion remote with a passage (48) at the axial channel (46) opens, which passage (48) radially inwardly directly opposite the feed line (41 a).

14. Cup tappet according to claim 1 or 13, characterized in that the inner part (9) relative to the housing (3) is secured against rotation.

15. Cup tappet according to claim 1 or 13, characterized in that the tappet (1) with one of the shirt (5) projecting against rotation (49) is provided.

16. Cup tappet according to claim 1, characterized in that the tappet (1) is shown as "Abschaltstößel", the inner part (9) is present without cam contact.